CA2223526A1 - Diving mask with lenses and method of fabricating the same - Google Patents

Abstract

A diving mask (10) having hemispherically-shaped lenses (12) mounted on a flexible gasket or portion (14) and fitted to the contours of a user's face.
Laser scanning or topographic mapping is used to determine the contours of the user's face. Edges of the hemispherically-shaped lenses (12) are then shaped to fit the contours of the face. As a result, the spherical center of the lenses substantially coincides with the optical nodal point of the user's (24), or the center of rotation of the eyes. This virtually eliminates the phenomenon of underwater magnification-distortion caused by the difference in refractive indices of water and air.

Description

DI~ING NL~8R ~IT~ LEN~E5 ~D N~ET~OD OF FABRICA~ING T~E 8~E
"
CROSS-REFER~NCE TO RELA~ED APPLICATIONS
This application is a continuation-in-part of co-re~;n~ application, Serial No. 08/114,551, filed August 30, 1993, ~nd entitled "DnrING ~AS~ T-~ C~C AND
D OF FABRICATING THE SA~~," wh~ch is a continuation-in-part of co-pending International Application No. PCTtUS92/07321, filed ~ugust 28, 1992, entitled "D~ NG ~ S~ ~ITH ~ V LENSES AND ~ET~IOD OF
FABRICATING THE SA~E," which designated the U.S.; and which is a continuation-in-part of co-pending application,.Serial No. 07/750,988, filed August 28, 1991, and entitled "DIVING
MASR WITH ~ :~ LENSES AND ~ETHOD OF FABRICATING THE
SAME." This application relies on Disclosure Dor~ nt No.
3S1148, filed MArch 30, 1994.

BACKGROUND OF THE INVENTION
The present invention relates generally to underwater face masks and, more particularly, to underwater diving masks having eyepieces or lenses mounted on a flexible g~sket.
In the past, a V'A riety of underwater f A ce masks have 2S been used ~or sporting and other activities ~uch as skin and scu~a diving. Early underwater face masks typically had several co~mon features, including a contiguous air 6pace shared by the diver's nose and eyes, generally ~1at, glass or plastic windows, eyepieces or ports fixed approximately perpendicularly to the wearer'8 straight-ahead viewing axis, ~nd a flexible rubber or pl~stic ~u~o L structure for holding the ports in pos~tion and trapping an air pocket against the wearer's face. A contiguous air pocket over both the wearer'~ nose and eyes, as Opposed to a mask covering the eyes only, allow6 ~or equalizing pressure inside the mask with ambient water pressure as the wearer ascends and descends in the water. Such equal~za~ion is necessary to avoid injury to the wearer z Such conventional flat-window ~ace mask ~share a variety of shor~com;ngs. The windows or eyepieces of conventional flat-window masks must be supported out ~rom the face. Above ~nd below water, the we rer'~ horizontal and vertical fields of view ~re severely limited by the flexible rubber or plastic ~tructures pro~iding ~uch ~u~OL L, thereby creating a ~ense o~ "tunnel vision" and a closed-in, c~austrophobic feeling. Above water, convention-al flat-window masks pro~ide no more than a 140 degree horizontal by 90 degree vertic~l ~ield of view. Below water, because of the ref~action-induced magnification distortion of an air water viewing system, discussëd more fully hereinbelow, this field of view is effectively reduced to approximately 105 degrees horizontal by 67.5 ~egrees vertical.
Additionally, conventional flat-window r~sk~ ~uffer quite significant magnification-distortion problems from the difference in refractive indices between water and air.
Specifically, objects viewed on an axis perpendicular to the window appear approximately 33% larger and 25~ closer than they actually are. ~he magnification-distortion of objects viewed off-axis is even larger.
Further, conventional flat-window masks create a significant amount of hydrodynamic drag and present a significant risk of slipping off the wearer's face if hit by an unanticipated or oblique-angle wave or current.
These ~nd other fl~t-window mask problems h ve ~ttempt-ed to be overcome, with less than 5ati5factory results, by ~pherically-shaped eyepieces or lenses used for underwater masks. For example, U.S. Patent Nos. 3,899,244, issued to Mulder on August 12, 1975, and 3,672,750, issued to Hagen on June 27, 1972, disclose underwater masks that use built-in corrective lenses in addition to spherically-shaped lenses to improve viewing under water. ~s ~uch, these masks do not provide optimum viewing characteristics under water without the use of additional corrective lenses. Other single and ~ultiple lens systems used for underwater face WO 96/41229 PCT~US96/09389 masks that do not provide optimum viewing conditions are disclosed in U.S. Patent Nos. 3,944,345, issued to DecoratO
on March 16, 1976; 3,040,616, icsued to Simpson on June 26, 1962; 2,088,262, issued to Grano on July 27, 1937;

2,928,09~, issued to Neufeld on March 15, 1960; and 1,742,412, ~ssued to O'Flanagan on January 7, 1930.
~.S. Patent No. 4,607,398, ~c~ to Fa~ Qn~ on August 26, 1986, d~closes a ~Ir~p and ret~n~r used for a diver's ~ask. U.S. Patent No. 3,051,957, issUed to Chan on Sept~mh~ 4, 1962, descr~bes a diving m~sX hav~ng a support-ing device used to hold the eyeglasses of a diver. In addition, U.S. Patent No. 4,856,120, issued to ~art on August 15, 1989, describe5 a purge valve used for a div~ng mask and a deflector attached to the mask and used to channel air bubbles expelled during purging to the sides of the mask. Another purge valve used for a diver's mask is disclosed in U.S. Patent No. 4,241,898, issued to Segrest on D~er 30, 1980.

St~ A~Y OF THE INVENTION
Accordingly, it i5 an o~ject of this invention to provide a diving mask which furnishes improved viewing characteristics under water.
It is ~nother object of this invention to pro~ide a diving mask which furnishes improved viewing characteristics under water, and may be used under water by divers who do not have to wear contact lenses or eyeglasses to correct eyesight when not under water.
It is ~till another o~ject of this invention to pro~ide a diving ~ask which furnishes i~L~ved viewing characteris-tics under water, and may be used under water by divers while not wearing contact lenses which correct eyesight above water.
It i~ still another object of th~s inventiOn to provide a diving mask which furnishes improved viewing characteris-tics under water, and may be used under water ~y divers while wearing contact lenses which correct eyesight a~ove water.

W O 96/41229 PCT~US96/09389 It is still anothex object of this invention to prOVide a div~ng masX which may be used both above and under water.
It is still another ob~ect of this invention to prOVide a diving mask which ~ay be usea both above and under water w~th addit~on~l _G~ ive ~enses if desired.
It i6 still another ob~ect of ~ is invent~on to provide a diving mask which ~urn~he~ a secure seal between the mask ~nd a wearer' 5 f~ce.
It ~ 6till another ob~ect of this invention to provide a method of fabricating such a diving mask.
These and other objects and advantages are attained by a diving mask having hemispherically-shaped lenses mounted on a flexible gasket and fitted to the contours of a user'~
face. Laser sc~nn;ng or topographical mapping is used to determine the contours of a user's face. The perimeter edge~ of the hemispherically-shaPed lenses are then sized to fit the contours of the f~ce. As a re~ult, the spherical center of each of the hemi~pherically-shaped len~es substan-tially coincides with the optical nodAl point of one of the user's eyes. This ~mprovement virtually eliminates the phenomenon of underwater magnification-distortion caused by the difference in refr~ctive indices of water and air.
Improved horizontal and vertical fields of view are also provided by the hemispherically-shaped lenses. A secure se~l is provided between the diving mask and a user's face by the flexible gasket.
-Another embo~im~t of the diving m~sk i~ provided having a standard pair of hemispherically-shaped lenses mounted on a contoured portion of the mask which is fitted to the contours of ~ user'~ face. The contoured portion is ~ounted on a flexible gasket.
In still another embodiment of the diving mask, the hemispherically-s~aped lenses are designed so that the spherical center of curYature of each of the lenses substzn-3~ tially coincides with the center of rotation of one of auser' 5 eyes.

In still another embodiment of the diving mask, a shaft i6 mounted on the hemispher~cally-sh~ped lerlFieF. The shaft is coupled to a pair of retractable corrective lenses, and may be used to lower the corrective lPn~eF to a position in front of ~ user'~ eyes ~nd to raise the lenses to a position abo~e the eyes. The correct~ve lenses ~ay be used by near-and fAr-~ighted users.
Tn ~till nother embodiment of the d~v~ng mask, the hem~pherically-6haped lenses ~re mounted on a ~upport portion having a peripheral flange. The iupport portion, in turn, is mounted on a flexible gasket of selected size.
The diving mask may have at least one purge valve in the support portion.
In still another embodiment, a diving mask is provided having a purge valve in at least one of the hemispherically-shaped lenses. The purge valve i~ located at the ~ront and bottom of the lens and in an Area used to collect water which has leaked into the mask. The collecting ~rea ~s angled to facilitate expelling water from the diving mask through the purge valve io that exhaust bubbles pass toward the back of the mask, away from t~e field of vision of a diver.
In still another embodiment, the diving mask is provided with a bottom lens which facilitates drainage of water from the mask. The bottom lens may also be used for viewing both above and below the water. The diving mask may also have an additional lens mounted inside the mask which may be used by either nearsighted or farsighted divers. A
member may be ~oined to the additional lens in order to provide trapped dry-air volume inside the mask.
In still another emboAi~nt of the diving mask, a baffle may be used with textured or coated surfaces in order to pro~ide a translucent ~~m~r for the purpose of eliminat-ing double vision. Also, the ends of the lenses may be bent 3s or formed inwardly toward a diver's face in order to provide a reduced air volume inside the mask.

CA 02223~26 1997-12-04 In still another em~odiment of the mask, hemispherically-shaped meniscus lenses are used to provide reduced weight and a reduced air volume inside the mask The curvatures o~ the inner and outer surfaces of the meniscus lenses are chosen to produce an effective zero diopter value under water. The spherical centers of curvature of the ~ni ~CUS lenses ~re located h~ne~th the centers of a di~er's eye in order to reduce the weight of the mask and to i~ve drainage.
In still another ~ho~ ~t of the diving mask, a perimeter clamp is used to clamp a conventional face ~eal to a support portion of the mask. Integral housings may be formed in the support portion for purge valves. Integral housings for the purge valves may also be formed in the perimeter clamp. A purge valve is provided for each lens.
In still another embodiment, a diving mask is provided with a supplemental lens or lenses located in ~ront of the hemispherically-shaped lenses for the purpose of holding water therein. The supplemental lens configuration zO provides above-water corrective lenses and hence clear vision when the diver raises his or her head out of water.
The supplemental lens configuration comprises a thin-walled zero power transparent plastic or similar material member engaging the diving mask to form a water-tight seal. In the preferred embodiment, the cavity formed by the supplemental lens may be filled through an opening with clear water and the opening -sealed with a non-porous material. Additionally, the upper edge of-the supplemental lens may be open to permit water passage. The supplemental lens arrangement may also provide purge valves for dissipating water which collects in the mask.
In still another embodiment, the diving mask having hemispherically-shaped lenses is provided with side wall lenses continuing from the hemispherically-shaped lenses to provide an outermost horizontal field-of-view. The side wall lenses extend from the hemispherically-shaped lenses to a visual horizontal peripheral line approximatelY

CA 02223~26 1997-12-04 perpendicular to the optical nodal point of each corresponding eye of said user's face. Each of the side -wall lenses extend from approximately ten degrees to approY;m~tely zero degrees from the visual peripheral line.
The side wall lenses compri~e either an outer radius continuing the curvature of the outside of the hemispherically-~haped lenses, ~nd an inner edge extending from the inside of said inner lens ~nd substantially parallel to the outer radius so that the side wall lenses maintain generally uniform thickness, o~ ~n outer r~dius continuing the curvature of the outside of said hemispherically-shaped lenses and an inner edge ex*ending from the inside of the inner lens and away from the inside of the inner lens, providing a ~econdary meniscus lens thereby improving focusing characteristics at edges of the user's horizontal field of view.
The various features of the present invention will be best understood together with further o~jects and advantages by reference to the following description of the preferred embodiments taken in conjunction with the accompanying drawings.

BRIEF DESCRIP~ION OF TH~ DRAWINGS
FIG. 1 is a front elevational view of a diving mask with two generally hemispherically-shaped lenses mounted on a flexi~le gasket or portion and fitted to the face of a user, illustrating the principles of the present invention;
FIG. 2 is a side elevational view of the diving mask of FIG. 1 shown worn on the head of the user;
30FIG. 3 is a partial cross-sectional view of the diving mask taken in the direction of arrows 3-3 shown in FIG. 1, illustrating how the spherical center of curvature of one of the hemispherically-shaped lenses ~ubstantially coincides with the optical nodal point of one of the user's eyes;
FIG. 4 is a cross-sectional view of the diving mask taken in the direction of arrows 4-4 shown in FIG. 2 also ~howing how the ~pherical center of curYature ~ubstantially coincides with the optical ~o~l point;
FIG. 5 i~ an enlarged detailed crosS-sect~on~l ~iew of a skirt portion of the flexible gasket of the diving ~ask of FIG. l;
FIG. 6 is an enlarged detailed cross-cection~l ~iew of the ~k~rt portion ~howing how one of the hemispheric~lly-~haped lenses is mounted on the skirt portion, ~nd how apertures are provided ~n the skirt portion to allow water to fill a cavity in the skirt portion, helping to provide a cushioning effect against the user'~ face;
FIG. 7 is a partial cross-sectional ~iew of another em~odiment of the diving mask having ~ turn~ng ~haft mounted on the hemispherically-chaped lenses, which may be used to lower retractable corrective lenses in front of a user's eyes;
FIG. 8 is a ~artial cross-5ection~1 view of the turn~ng Ghaft and hemispherically-shaped lenses taken in the direction of arrows 8-8 ~hown in FIG. 7;
FIG. 9 is a partial cross-sectional view of the diving mask, taken like ~IG. 7, illustrating how the turning shaft ~ay ~e used to raise the retractable corrective lenses from ~ position in front of the user'5 eyes, as ~hown in PIG. 7, to a position above the eyes;
FIG. 10 is an exploded view of another embodiment of the diving mask having ~ standard pair of hemispherically-shaped lenses mounted on a contoured portion of the mask which is fitted to the contours of a user's face, and mounted on the flexible gasket;
FIG. 11 is an exploded, enlarged~.detailed cross-~ectional view of the skirt portion of the flex~ble g~sket, the contoured portion of the m~sk and one of the hemispherically-shaped lenses, showing the contoured portion attached to the gasket;

W O 96/41229 PCT~US96/09389 FIG. 12 i~ an enlarged detailed cross-sect~nAl view, taken liXe F~G. 11, showing the hemisphericallY-8haPed lens attached to the contoured portion;
FIG. 13 is a ~ront ele~a~o~l ~iew of another ~ho~_ ment o~ the diving m~sk shown worn on the head of A user, having a pair o f hemispherically-~h~r~ n~ with purge ~valves therein ~o~.Led on the fl eY~ ~l ~ gacket;
FIG. 14 is ~ ~ide elev~tion~l!v~ew of the diving ~sk of FIG. 13;
FIG. 15 is a partial cross-sectional view of the diving mask taken in the direction of arrows 15-15 ~hown in FIG.
13, illustrating how the hemispherically-shaped lenses may be ~n~cted to ~traps and the flexible ga~ket by a clamp ~nd flange;
FIG. 16 is a ~chematic ~e~ ~entation illustrat~ng how the spherical center of curvature of each of the hemispheri-cally-shaped lenses of FIG. 13 substantially co;nci~eC or aligns with the center of rotation of one of a user's eyes and falls within a predetermined acceptable zone of mis-alignment;
FIG. 17 is a perspective view of ~nother emboA~nt o~
the diving mask having a p~ir of he~;~pherically-shaped lenses mounted on a peripheral flange of a support portion of the mask;
2s FIG. 18 i5 a partial cross--sectional view of- another embodiment of a shaft shown mounted on the hemispherically-shaped lenses which may be used to raise and lower correc-tive lenses in front of A user'~ eyes;
FIG. 19 is an enlarged cross-section~l view taken in the direction of arrows 19-19 shown in FIG. 18;
FIG. 20 i~ a partial cross-5ectional view of another embodiment of the diving ma~k taken in the direction of FIG.

4, ~howing a hemi~pheric~llY-sh~ped lens having a ~ottom lens at the bottom of the hemispherically-shaped lens;
FIG. 21 is an enlarged detailed view taken as indicated by arrows 21-21 shown in FIG. 20, showing how an O-ring may be used to provide a seal between the bo~tom lens and a peripheral ~lange o~ a support portion of the mask;
FIG. 22 i8 an enlarged det~;le~ ~iew taken like FIG.
21 ~howing snother way of using ~n o-ring to pro~ide ~ seal;
SFIG. 23 i~ a partial cro5s-sectional v~ew of another embo~ nt o~ the di~g 2ask t~ken l~ke FIG. 20, showing a hemispherically-shaped lens with a bottom lens ~nd ~nother lens mounted inside the mask;
FIG. 24 i~ a partial cross-sectional view taken like FIG. 20 showing a ~nvexo-concave bottom lens;
FIG. 25 is a partial cross-sectional ~iew taken like FIG. 20 ~howinq a plano-concave lens mounted inside a bottom lens;
FIG. 26 i~ a partial cross-sectional view taken in the direction of FIG. 3, showing how an end portion o~ one of the hemispherically-shaped lenses may be contoured inwardly toward a diver's face in order to re~c~ the ~ize of the diving maFk and the tra~ped air ~pace or volume within the mask;
20FIG. 27 is a partial cross-sectional view taken in the direction of FIG. 3, ~howing how a central translucent member may be attached to the hemispherically-shaped lenses where the lenses are joined together in order to prevent double ~ision;
25F~:G. 28 i5 a parti.al cross-sectional view of another embodiment of the diving ma~k taken like FIG. 20, ~howing a hemispherically-shaPed lens with a bottom lens, And another lens of uniform thickness m3unted inside the mask in order to provide a trappea dry-air ~pace or ~olume inside the mask;
FIG. 29 is a partial cross-sectional view o f another embodiment o~ the diving mask taken like.FIG. 20, showing hemispherically-shaped len5 with A bottom lens, and another convexo-concave len8 ~ounted inside the mask in order to provide a trapped dry-air ~pace or volume inside the mask;

~ 11 FIG. 30 is an enlarged detailed view of the bottom - lens, with ~ plano-conc~ve lens mounted therein, ~nd o~ a peripheral flange and support portion of the ma5k, 8howing how O-rings may be used to mount the plano-concave ~ens inside the bottom lens;
FIG. 31 is a ~chematic representation of two hemis-pherically-shaped m~ tl~ lense~ of another ~h~A~ment of the diving mask having different outer and ~nner curvatures, each lens having ~pherical centers of cuLv~LuLe of its outer and inner surfaces that are coplanar, or that fall on a plane pas~ing through the center of the eye of a user;
FIG. 32 ic a ~chematic representation of two hemi~phe-.
rically-shaped ~n~ficus lenses of another em~o~imPnt of the diving mask having different outer And inner curvatures, each lens having ~pherical centers of curvature of its outer and inner surfaces that are not coplanar;
FIG. 33 is a schematic representation of a hemispheric-ally-shaped meniscus lens having a bottom lens, which illu-strates how changes in the ef~ective diopter:vAlue o~ the meni~cus lens can be matched with the type of bottom lens used for the diving mask, ana illustrates how the cpherical centers of curvature of the outer and inner surfaces of the meniscus lenses are located ~elow the center of a diverls eye;
FIG. 34 ic a ~chematic representation of two different hemispherically-shaped meniscus lenses, illustrating the differences between a lens having spherical center~ of curvature that Are coplAnar and a lens having spherical centers of curvature that are not coplAnar;
FIG. 35 ~ n ~ide elevAtion~l view of a support por-tion, perimeter clamp and conventionA 1 f lexible face seal of another embodiment of the diving mask, the Cupport portion having a peripheral flange for mounting a pair of hemispherically-shaped lenses, _nd two integral housings for mounting purge valves;

FIG. 36 is a front elevational view, 8howing the support portion and flexible face seal of FIG. 35;
FIG. 37 is a bottom plan ~iew of the 8upport portion~
perimeter clamp and flexible face ~eal of FIG. 35;
5FIG. 38 is an enlarged cross-sectional Yiew of a part of the ~upport portion of FIG. 5 and of one of the housings of the support portion, ~howing a purge valve mounted in the housing, and a hemispherically-shaped lens mounted on the ~upport portion;
10FIG. 39 is a front elevational vie~ of two generally hemispherically-shaped meniscus lenses of the diving mask;
FIG. 40 is a rear elevational view of the meniscus lenses of FIG. 39;
FIG. 41 is a rear perspective view of the meniscus lenses of FIG. 39;
FIG. 42 is a top plan view of the meniscus lenses of FIG. 30;
FIG. 43 is a bottom plan view of the meniscus lenses of FIG. 39;
20FIG. 44 is a cross-sectional view taken in the direction of arrows 44-44 6hown in FIG. 42;
FIG. 45 is an exploded cross-sectional view of another embodiment of the diving mask taken across a perimeter clamp, flexible face seal, support portion and bottom lens, showing a housing in the clamp for mounting a purge valve;
FIG. 46 is a top schematic plan view of a supplemental lens arrangement used in conjunction with two hemispherically-shaped meniscus lenses of an embodiment of the diviny mask h.aving different outer and inner curvatures, the supplemental lens arrangement providing a zero power lens and clear vision for a diver raising his or her head out of water;
FIG. 47 illustrates a schematic side view of the supplemental lens arrangement;
35FIG. 48 is a top schematic plan view of the two hemispherically-shaped meniscus lenses of an embodiment of W O 96/41229 PCT~US96/09389 the diving mask having different outer and inner curvatureS
of the current invention;
FIG. 49 is a top schematic plan view of the meniscus lenses of the current invention having an added pair of uniform thickness side wall lenses; and FIG. 50 is a top schematic plan view of the meniscus lenses of the current invention having an ~P~ pair of sidewalls providing formed to i~e focusiny characteristics at the most extreme edges of the field of view.

PESCRIPTION OF THE PREFERRED EMBODIMENTS
The following specification taken in conjunction with the drawings sets forth the preferred em~o~iments of the present invention in such a manner that any person skilled in the art can make or use the invention. The embodiments of _he invention disclosed herein ~re the best modes contemplated ~y the inventor for carrying out his invention in a commercial environment, although it should be understood that various modifications can be accomplished within the parameters of the present invention.

FIGS. 1 and 2 ~how a preferred embodiment of the diving mask 10 of the present invention. The diving mask 10 has two eyepieces, or generally h~m i~pherically-shaPed lenses 12, ~ounted on a flexible gasket or portion 14 of the mask 10. Each lens 12 may be a ~egment or portion of a ~phere.
It is ~portant to note that each lens 12 may be smaller or larger than a h~m;~phere or may be only a r?~r~~t or portion of A h~sphere. Therefore, "generally hem~pherical-ly-shaped lenses" or "hemispherically-~hAre~ lenses, n AS
used herein, refers to lenros that are shaped like he~phe-rically-shaped lens, or a portion thereof, or each such lens may be a segment or a portion of ~ ~pher~cally-chaped lens that is maller or larger than one half of a sphere, or smaller or larger than a hemi~phere.
The lenses 12 are preferably made o~ plastic, glass, or the like. However, any transparent, optically clear material may be used for the lenses 12. The th~ckness of the lenses 12 preferably has A r~nge of appr~m~tely from about 1/20-inch to about 1/2-inch. However, any thickness may be used. It is i~portant to note that ~ny in~
thickness that provides structural integrity may be used for the lenses 12. The diving mask 10 is ~ecured to the face 16 of a user by straps 18 that are preferably fused or otherwise attached to the lenses 12 by, for example, members 17, or the like. As ~hown in FIGS. 1 and 3, the lenses 12 are preferably fused together at edge 20 Adj~cent the bridge o~ ~ user~ 6 nose. However, t21e lenses 12 may be ceparated by part of the flexible portion 14 running along the bridge of the user'~ nose (not shown), if desired.
The flexible g~sket or portion 14 i~ preferably made out of a flexible or elastic plastic or rubber material such as silicone, neoprene, or the like. However, any other flexi~le material may be used for portion 14. A nose portio~ 22 of flexible portion 14 is also provided so that a seal is furnished ~etween the user's face 16 and the diving ~ask 10, and an air space is provided between the W O 96/41229 PCTrUS96/09389 1~

lenses 12 and the user's eyes 24 and face 16 under the lenses 12. The air ~pace provides air pressure insid e the d~ving ma~k 10 which counteract~ the ambient water pressure that exists outside the mask 10 when the u~er i8 under water and protects the user'~ eyes 24.
As ~ c~ced below, the contour~ of the user's face are s~ne~ or topogrAphically ~rr~ and the lenses 12 are ~haped to closely fit the contours of the user'q fAce 16.
In order to provide optimum Yiewing characteristics under water, the edges or ends 42 of the lenses 12 (Gee FIG.
6) must closely fit the contours of a user's face 16 ~o that the spherical center of cur~ature of the hemispherically-6haped lenses 12 substantially coincides with the optical nodal point 26 of the user' 5 eye~ 24 a~ illustrated by arrows 28 and 30 in FIGS. 3 and 4, respectively. When the ~pherical center of curvature and optical nodal point ~ubstantially coincide, thi~ results in virtually ~l~m~At-ing the phenomenon of underwater magni f ication-di~tortion caused by the difference in refractive ~ndices of water and air wh~ch causes objects to appear About 33~ larger and about 25% closer than they actually are. In addition, such coinciding o~ the spherical center of curvature and optical nodal point pro~ides hemispherically-shaped lenses 12 that have a horizontal field of view of about 180 degrees and a 2S vertical field of view of about 150 degrees.
The outside ~m~ter of the hemispherically-shaped le~ses 12 also determines the distance ~rom the lenses 12 that a user's eye 24 must focus in order to see ~n image formed by an o~ject under water. The theoretical basi~ for thi~ ~8 Snell' F Law of Refraction, which for a basic hemispherical lens and paraxial light rays nay be expressed as:
n nl nl _ n s sl R
where W O 96/41229 PCT~US96/09389 n = the index of refraction of the medium in which the o~ject is located;
nl = the index of refraction of the lens;
~ c the di~tance of the ob~ect from the S outer ~urface of the lens;
= the location of the image formed from the outer surface of the lens; ~nd R = the radius o~ cur~ature of the lens.
Using n=1.34, the index of refraction of salt water, and nte1.49, the index of refraction of plexiglass, the following table indicates the distances from the front ~:urface (cornea) of a user' 5 eye 24 that the eye 24 must focus for different diameter hemispherically-shaped lenses having a lens thickness of .25 inches to clearly see the apparent image of an object located at different distances from the lenses. All dimensions are presented in ~nch~s.
The chzrt assumes a distance from a center of rotation 150 of a person's eye to the outer surface of the cornea to be .5 inch. The importance of the center of rotation 150 is discussed later in connection with FIGS. 15 and 16.

E~x ~of~fiomTokc~omTofx~om Tobc~ ~ ~of~*o~

3.0 ~R S.f~ ~.t90 ~.. ~2 ~.19S
~ ~ 3.m ~ .n3 4-~9 s.ln 4.0 ~,:~1 5.0~/ 5~565~6~ 6.151 4.~U 5.n~ 6.~t 7.UI

5.0 5.~ 6S~ .113 S.6tf ~.991 7.9~ ~~ 9~S

6.0 5.~U ~5n ~n ~n ~o.cn 6~ 6.u~ ~ 0;~-.0 ~.672 ~.6't5 lO.~Ji2 tl.l39 12.t~U
~ 6.9U ~.~91 I0.n~ . Il.nl 13.cn ~.o ~;~s 9.~5 11~912.1~ 1~.0~1 t~ ~9 10.161 ~.1~ U.~- 1~.~5 9.0 7.U~ 10.617 n.m 1~.~53 ~s.~

Taking an example where n=1.34, the index of refr~ction of salt water; n~=1.49, the index of refraction of plexi-glass; R=2.75 inches, the radius of curvature of a ~.5 inch diameter dome lens; and s=22.75 inches, the distance fro~
the lens' outer surface of an object 25 inches from an eye's corneal ~urface, the ~olution for ~l is -342.085 inches;
25i.e., the image is formed 342.085 i~hes from the dome lens' outer surface on the opposite side relative to the o~ject.
The above equation is then s01ved for this image using the inside surface of the dome lens in which s, the object distance, i8 now -342.335 inches (comr ncating for the .25 inch thicknes~ of the dome lens), n=1.49 (for the plexi-glass), n~=l (for air), and R=2.5 inches (compensating for the .25 inch thickness of the dome lens). This results in a value for sl of -4.991 inches, i.e., the image seen by the user is 4.991 inches from the inside surface of the dome lens toward the ob;ect. Add to this 2.5 inches for the inside radius of the dome lens, less the .5 inch for the distance from the center of rotation of the eyeball to the outer corneal surface, to arrive at 6.991 inches, as indicated in the chart for a 5.5 inch diameter dome and a 25 inch object distance.
The exterior diameter of the hemispherically-6haped lenses 12 preferably has a range of from about 4.25 ~nches to about 9 inches. Kowever, ~ny size diameter ~ay be used = ==-for the lenses 12 depending on the wearer's vision, e.g., myopic wearers may opt for smaller sized domes.
Referring now to ~IGS. S and 6, a skirt portion 32 of the ~lexible portion 14 i~ shown having a ~ody portion 35 S with ~n elongated ca~ity 37 ~-nn i ~ the length thereof, flexible curved extension~ 34 and edgeG 36 that contAct the contours of a user'~ S~ce 16 (see FI~. 3), ~nd cle~s ~rms 38 that extend ~way from the f~ce 16. The clevi~ ~rms 38 form a ~h ~nne1 40 which engages the ends or edges 42 of the lenses 12 (see FIG. 6). The lenses 12 may be attached to c~nn~l 40 using any desirable method ~uch as by force fitting, using adhesi~e, by fusion of the parts, w~l~;n~, or by any ~uitable fastening or clamping means. The edges 42 of the lenses 12 are formed to match the contours of a user'~ face 16 (see FIG. 3) which ~re me~sured by scanning or topographical mapping as ~c~s-~ed below.
A secure seal is pro~ided between the flexible gasket 14 and the user's face 16. The skirt portion 32 of the g~sket 14 has a plurality of apertures 44 passing through body portion 3s And into elongated ca~ity 37. The apertures 44 preferably are spaced about 0.5 inch apart along cavity 3~ and cause the cavity 37 to fill with water when a user is under water, so that pressure inside the cavity 37 is equal to ambient water pressure, which provides a ~hioning effect against the user's face 16.
In order to fit the perimeter edges 42 of the lenses 12 to the contours of ~ user's ~ace 16, 1A ser scanning or topographical mapping may be used to accurately determine the contour~ of the face 16. Apparatu~ ~nd te~;que which may be used for laser ccanning a user's face are disclosed, for example, in U.S. P~tent No. 3,636,250, issued to Haeff on January 18, 1972, the di5closure of which is hereby incorporated by reference. However, any a~ailable tech-ni~ue, including any high-speed, optical sc~nning technigue or topographical mapping technique, may be used to determine the contours of a user's face 16.

FIGS. 10 through 12 show another embo~;~e~t o~ the - diving mask 10 having a ~t~n~d pair of hemi~pherically-shaped lenses 12 mounted on a contoured portion 46 of the mask 12. The contoured portion 46 is attached to the skirt S portion 32 o~ the ~lexible gasket 14, as shown ~n FIGS. 11 ~nd 12, with exten~ion 48 of portion 46 engaging channel 58 formed by cle~is ~rms 56 of the skirt portion 32 ~nd edges or surfaces 50 ~nd S2 of portion 46 being in contact with edges or surfaces 60 and 61 of skirt portion 32. The contoured portion 46 may be ~ttached to the skirt portion 32 by force fitting, using adhesive, by fusion of the parts, or the like.
Edges or surfaces 50 and 52 of ~he contoured portion 46 are shaped to closely fit the contours of a user' 6 face 16 using laser scAnnin~ or topographical mapping as dis-cussed above. Contoured portion 46 may be made out of plastic, or any desirable material, and edges 50 and 52 may be cut, shaped, molded or otherwise formed to fit the contours of the user's face 16.
It is important to note that edges 50 and 52 and exten-cion 48 of the contoured por~ion 46 may have ~ny de~irable configurations or shapes, and the configuration ~nd shape of clevis arms 56 and channel 58 of the skirt portion 32 ~ay also be varied or designed to provide any desirable joint between portions 32 and 46. The skirt portion 32 preferably has the elongated cavity 37, apertures 44 and flexible curved extensions 34 discussed aboye.
The standard pair of lenses 12 may be attached to the contoured portion 46 by engaging end or perimeter edge 62 of the lenses 12 in groove S4 provided in portion 46 by force fitting, using ndhesive 64, by fusion of the parts, welding, or by any suitable fast~nin~ or clamping means.
Also, the configuration or shape of end 62 and groove 54 may be varied to provide any desirable joint.
A majority of divers may use the above described diving mask 10 because the preferred exterior diameter of the W O 96/41229 PCTrUS96/09389 lenses 12 has a range of from about 4.25 inches to about s.o inches, resulting in focusing di~tances of from about 4.5 ~nr7-~C to about 16. o in~-h~: in front of the diving mask.
Most diver~ will be able to focus their eyes within these distances. Therefore, ~ost di~er5 will be able to use the di~ing mask 10 without the need to use correcti~e lenses.
The dif~erent sizes of hemi~pherically-~haped lenses 12 yield di~ferent effective diopter values under water.
Diopter, as is wetl known in the ~rt, is a unit of measure-ment of the refraCti~e power of lenses equal to the recipro-cal of the focal length ~easured in meters. The following table lists the effective diopter values under water ~or different sizes o~ hemispherically-shaped lenses. For purposes o~ calculatin~ the diopter ~alues, the distance from the center of rotation 150 of a person's eye to the outer ~urface of the cornea was assumed to be 0.5 inch, the wall thickness of the lens 12 was assu~ed to be 0.075 inch, 1.34 was used for the index of refraction of salt water, and 1.586 was used for the index o~ refraction ~or the polycarbonate material which forms lenses 12.

Exler~o~ ~ffect~v~
Dom~ D~opter D~ameter ~luc~
~ndes Water 3.0 -7.934 3.5 -6.628 4.0 -5.690 4.5 -4.985 5.0 -4.4~5 S.5 -3.995 6.0 -3.634 6.S -3.333 .7.0 -3.077 7.5 -2.8 8.0 -2.669 8.5 -2.503 9.0 -2.356 As indicated in the above table, the preferred exterior diameter range of the lens 12 from about 4.25 inches to about 9.0 inches results in an effective negative diopter range under water o~ from about -5.3 to ~bout -2.4.
Effective negative diopter values for lenses with exterior diameter sizes below 4.25 increase significantly and at a much faster r2te as the lenses get smaller. Therefore, most divers will not be able to use the smaller size of lenses (i.e., ~elow 4.25 inches) without corrective lenses, because of the iarger effective ne~ative diopter values yielded by these smaller lenses under water.
A majority o~ divers are represented by individuals who are under ~bout 30 year5 of age ~nd either have 20-20 vision or are near-sighted. These di~ers under 30 years of age - have the ability to accommodate excessive negative diopter values because of the elasticity of the focusing parts (muscle, etc.) of their eyes. Therefore, a majority of 3~ divers will be able to accommodate the negative diopter range o~ lenses 12 having an exterior diameter range of from W O 96/41229 PCT~US96/09389 ~bout 4.25 inches to about 9.0 inches. ~lthough the elasticity of the focusing part~ of ~n eye decreases with ~ge, ~ome older divers will also be a~le to A~o~mo~te ~re6cive negative diop er ~alues.
FIGS. 7 through 9 ~how yet ~nother e~ho~ent of the di~ng mask 10 for use w~th corrective l~r~c having a turning sha~t 66 which ~lidably and rot~ta~ly engages a ~leeve 68 mounted to the hemispherically-shaped lenses 12.
The sleeve 68 engages a gaske~ 70 made out of a flexible 10 ~naterial ~uch ~5 rubber,, or the like, which i5 mounted in an ape~L~e 72 in the lenses 72. Flanges 74 of the gasket 70 engage the lenses 12 providing a seal between the gasket 70 and lenses 12.
Flanges 76 of an upper portion 78 of the sleeve 68 bear lS against the gasket 70 helping to provide a ~eal. In addition, an o-ring seal 77 is provided in upper portion 78 as shown in FIG. 8. Also, an A~n~l A~ portion 80 at the inside cylindrical surface of the g~sket 70 engages ~n annular groove 82 in the outer cylindrical surface of the sleeve, providing a further seal.
The rotating shaft 66 has a pin 84 attached to an upper portion 86 thereof which ~lidably engages ~n elongated slot 87 in the sleeve 68 so that the shaft 66 may be grasped by a knob 88 at the top of the shaft 66 and pulled upward. The shaft 66 also has a lower portion 90 which is connected to the upper portion 86 by a connecting member 92 having upper and lower balls 94 and 96, respectively, ~ttached thereto.
Upper ball 94 rotatably engages a spherically-shaped cavity 98 in the upper portion 86 of the shaft 66 GO that a universal joint i5 provided and upper portion 86 is free to rotate about its longitudinal axis. ~nother pin 100 is attached to the lower portion 90 of the shaft 66. This pin 100 also slidably engages elongated slot 87 in the sleeve 68 which also allows the lower portion 90 of the shaft 66 to be moved upward by pulling upward on the knob 88.

W O 96/41229 PCT~US96/09389 Pin 100 ~lso slidably engages elongated slot6 102 in slotted ar~s 104. The slotted ~rms 104 are pivot~lly engaged at one end of each arm to pins 106 att~ched to lugs 108 ~t opposite slides of the ~leeve 68. Elongated members 110 att~ched to ~ pair of retr~ctable ~o~ Live len~e~ 112 are att~ch~ to the other ends of the slotted ~rms 104.
In order to po~tion the ~Gr~-live l~r~ 112 in position in front of ~ user' 8 eyes 24 ~s shown in ~IG. 7, the lower port$on 90 is allowed to drop toward the bottom 10 of the sleeve 68 until the ~ottom surface 114 of the knob 88 comes $nto contact with the top 116 of upper portion 78 of the sleeve 68. Alternatively, the different part~ may be sized so that downward movement of the 6haft 66 is stopped when pin 100 comes into contact with the lower end 118 of ~lot 87 in the sleeve 68.
As the shaft 66 moves downward, the corrective len~es 112 rotate as indicated by ~rrow 120 in FIG. 7 ~s arms 104 pivot about pins 106 until the lenses 112 re~ch ~ posit~on in front of a user's eyes as shown. If the user wi~hes to 20 move the lenses 112 away from hi~ or her eyes 24, thiG i5 accomplished by pulling upward on knob 88 wh$ch c~uses sh~ft 66 to move upward and the lenses lS2 to rotate ~5 arms 104 pivot about pins 106 as illustrated by Arrow 122 shown in FIG. 9. When pin 84 reaches the top end 124 of slot 87, the user may simply rotate the upper portion 86 of shaft 66 by turning knob 88 until pin 84 engages horizontal slot 89 at the.top end 124 of slot 87. The shaft 66 will then be held in place by pin 84 engaging slot 89 and the lenses 112 will be moved to ~ position above the u6er's eyes 24.
If the user wishes to lower the len~es 112 ~Aga$n to A
position in front of his or her eyes 24, then knob 88 may be rotated so that pin 84 disengages from slot 89, and the lenses 112 may be lowered as described above.
Another embodiment of a shaft 182 is shown in FIGS. 18 and-19. The shaft 182 slidably engages a sleeve 178 mounted on the hemispherically-shaped lenses 12. The sleeve 178 engages gasket 70, which i6 ~ounted in a~ Lule 72 in the lensec 12, a~ discussed above for the ~hoA~nt shown in FIGS. 7-9.
An elongated ~mher lll, ~t~rhe~ to ~ pair of retr~ct-S ~ble corrective lenses 112, pA~r~~ through ~n a~eLLu~e 188in the ~h~t 82, near the lower end of the ~haSt 182.
~ h.~- 111 may be welded to the chaft 182, or otherwise attached to ~haft 182 by adhes~ve, or the like.
~he Gleeve 178 has an elongAted slot 180 pas~ing there-through, which ~llows the correcti~e lense~ 112 to ~e raisedand lowered, by gr2sping knob 88 at the top of the ~haft 182, and ~y pulling upward or p--~h~ downward on the~ knob 88. Downward movement of the lenses 112 mAy be Gtopped by ~izing the ~haft 182 and ~leeve 178 ~o thAt elongated member lS 111 comes ~nto contact with lower end 186 of the ~lot 180, or bottom ~urface 114 of the knob 88 comes into contact with the top 116 of upper portion 78 of the sleeve 178.
The o-ring seal 77 holds the shaft 182 in place when the corrective lenses 112 ~re in an upward position, as illustrated by dashed lines in FIG. 18. Any other desirable means may be used to hold the shaft 178 in the upward position.
FIGS. 13 through lS ~how another embodiment of the diving ma~k 10 having a pair of hemispherical}y-6haped 2S lenses 12 with purge valves 12'6 therein mounted on the flexible gasket 14. A diver or user may expel or force ~ny water inside the mask 10 through the purge v~lves 126 by exhaling through hi~ or her nose. The purge valves 126 are designed to permit air or fluid to flow from inside the diving mask lO to outside the mask 10, but do not permit such flow into the mask 10. Thus, water may be purged from inside the diving mask 10 through the valves 126 without allowing leakage into the mask 10. Any suitable purge valve 126 may be used ~uch as the purge valve described in U.S.
3~ Patent No. 4,856,120, issued to Hart on August 15, 1989, the .

WO 96/41229 PCTAJS96/09389 2~

disclosure of which is hereby ~ncorporated by reference thereto.
One or more purge valves 126 m~y be used for the diving mask 10. For example, one valve 126 may be u8ed for e~ch S lens 12. AlL~o, only one purge ~alve 126 ~ay be ul;ed for the diving ~ask 10, nd ~ d~ver mAy tilt his or her heAd b~c3c ~nd forth to move w~ter from the lens 12 without t~e vAlve 126 to the len~; 12 wi'ch the ~ralve i26 prior to purging the water ~rom the mask 10.
EAch o~ the lensel; 12 h~ving one of the purge ~rAlves 126 preferably has a collecting rrea 128 near the front and bottom of ~uch lens 12 as e:hown in FIG. 14. The collecting area 128 i8 preferably formed as ~hown in ~IG. 14, at nngles 130 and 132 as measured from horizontal and vertical l~nes, respectively. Angle 130 preferably has a range of from about 30 degrees to About 90 degrees, ~nd ~ngle 132 may be ~ny size up to about 60 degrees. However, angles 130 ~nd 132 may ~rary ~s desired.
Water that has entered the lens 12 of the diving mask lo past the flexible g~sket 14 will move toward the bottom of the lens 12 and into the collecting area 128. ~ngles 130 and 132, help to prevent collected water from ~ h~l~g out of the collecting area 128. Also, the location of the purge valve 126 at the }~ottom of the collecting area 128 and angles 130 and 132 help to direct bubbles formed when water i5 exhausted out the valve 126 toward the back of the diving mask 10, away from the field of vision of a diver.
Angles 130 and 132 help to prevent water ~rom sloching or moving out of the collecting area 128 when a diver'~; head i5 ~n a ~rertical position aE; shown in FIG. 14, and when the diver i5 in a prone E;wimming position under water with his or her neck bent upward at approximately a 45 degree angle.
If water trickles into the diving mask 10 while the diver is in a prone swimming position And looking downward, the diver may purge water trapped inside the mask 10 through valve 126 by moving his or her head and/or neck upward at approximately a 45 ~egree ~ngle, and then exhaling through his or her no~e to ~orce water out of the mask 10 throu~h ~lve 126.
FIG. 15 shows how the hemispherically-sh~ped len~C 12 may be connected to ~tr~ps 18 ~nd the ~lexible g~sket 14 by a cl~p 134 ~nd ~ mpnt fl~nge 136. ~he ~l~nge 136 may be ~olded or formed ~8 an ~ntegr~l part of the len5es 12, or att~ched to ends or edges 138 of the lenses 12, which engage channel 137, as ~hown in FIG. 15, by adhesive, fusion, welding, or any ~uitable fast~n~ mean~. The alignment flange 136 has extension 140. However, any suitable ~hape or configuration may be used for the flange 136. End portion 142 of the flexible gasket 14 is disposed in channel 144 of the clamp 134, ~olds around the extension 140, and is clamped between the flange 136 and extension 140. Clamp 134 may be attached to flange 136 by adhesive, welding, fasteners, or ~ny suitable means. The straps 18 are atta~hed to extensions 146 of the clamp 134.
As illustrated in F~G. 15, the lenses 12 ~re sized And mounted on the flexible gasket 14 so that the spherical center of curvature of each of the lenses 12 with a radius 148 substantially falls on, or coincides with, the center of rotation 150 of the corresponding eye 24 of a diver surrounded by the lens 12. The center of rotation 150 of a person~s eye 24 i~ from about 0.5 inch to about 0.65 inch behind the front surface of the cornea. If the center of curvature of the lenses 12 substantially coincides with the center of rotation 150 of a diver'~ eyes 24, ~iewing distortion will be minimized when ~ diver's eyes 24 pan, tilt or rotate in their corresponding eye sockets.
It is the intention of this invention that any suitable means may be used to mount the lenses 12 on the flexible gasket 14 so that the center of curvature of the lenses 12 su~stantially coincides with the center of rotation 150 of the eyes 24 of a di~erl As such, alignment o~ the centers of curvature and rotation may be achieved by fitting or forming the lenses 12 to match the contours of a diver ' s face 16, or a f:t~ d pair of lenses 12 may be mounted on a contoured portion of the mask 10 fitted or formed to match the contours of the diver'~ ~ace 16, all ~s descr~bed ~n the above ~cl~c~on. In a~dit~on, predeter~ne~ 8iZes may be ~elected for the flex~ble gAsket 14, clamp 134 .~nd fl~nge 136 ln order to mount different ~zes o~ lenses 12 on the div~ng ~ask 10 o that the centers of curvature ~nd rotat~on ~re ~ ne~ within An ~cceptable zone of m~ gnment, AS
discussed below.
FIG. 16 is a schematic represent~tion illustrAting how the spherical center of curvature of each of the he~~he~i-cally-shaped lenses 12 of the present invention i~ ~ntended to substantially coincide or align with the center of rotation 150 of a diver' 5 eye 24, and fall~: within a predetermined acceptable zone of misalignment illustrated by region 152, which represents both horizontal and vertical misalignment.
The optical nodal point 26 of a diver's eyes 24 is the point at which the spherical center o~ curvature of the lenses 12 ~hould align or coincide with if the eyes 24 do not pan, tilt or rotate in their eye ~ocket6. The optical nodal point 26 is about 7 mm behind the front surface of the cornea of an eye. However, because a diver's eyes 24 move 2S in their sockets, the spherical center of curvature o~ the lenses 12 ~hould align or coincide with the center of rotation lsa of the di~er's eyes 24 to Achieve optimum ~ision through the lenses 12.
It is the intention of the present invention to substantially align the centers o~ curv~ture ~nd rotation in order to achieve improved vi~ion through the he~ispherically-shaped lenses 12 of the di~ing mask 10.
Radius 154 shown in FIG. 16 represents ~ particular size ~ lens 12 having a spherical center o~ curvature that coin-cides with the center of rotation lS0 of an eye 24. Radii 156 and 160 represent two other sizes of lenses 12 having centers o~ curvature 158 and 162, respectively, that do not coincide exactly with the center of rotation of the eye 24.
However,.the centers o~ curvature 158 and 162 fall Within the prede~r~e~ ept~ble zone of ~ m~nt of the present i"~"Lion represented in ~IG. 16 by the three di~ensional region 152. nSubstantially~ co~n~ F or ~ligns ~with, ~ u~ed herein, ~eans thAt the spherical center o~
curvature o~ a lens 12 f~lls within the predeterm~n~
~ccept~ble zone of misalignment represented by region 152 80 that i.. ~ ed vi6ion i8 provided by the lens 12.
The two hPmispherically-shaped lenses 12 are joined along edge 20. AS a re ult, the distance 164 between edge 20 and the bridge 166 of a diver's nose 168 sho.uld be m~ nim~ zed to prevent vision distortion through the lenses 12 due to edge 20. Preferably, distance 164 has a range of from about 1 cm to ~bout 50 cm.
The present invention will allow ~ ma;ority o~ divers to use standard lenses 12 mounted on the diving mask 10 that have centers of ~pherical curvature that fall within the predetermined accepta~le zone of ~i~ gnment or within region 152. However, larger diameter lenses 12 wil} provide a larger predetermined acceptable zone of misali~ent than smaller diameter lenses 12. Therefore, for ~u~ses o~ the present invention, the exterior diameter of the lenses 12 preferably has a range of ~rom about 4.25 inches to ~bout 9 inches.
FIG. 17 shows another embodiment of the diviny mask 10 having a pair o~ hemispherically-shaped lenses 12 mounted on a peripheral flange 174 of a support portion 169 of the mask 10. The ~upport portion 169 has a portion 170 that is clamped (by, e.g., clamp 134), or is otherwi~e fastened to the flexible gasket 14. Portion 169 also has another portion 171 which covers nose portion 22 of gasket 14 that fits around a user's nose, an upward nose portion 176 3s connected to portion 171, and portion 172 which connects peripheral flange 174 to portions 170 and 176.

The ~upport portion 169 shown in FTG. 17 may be fa~ri-cated ~s an integr~l piece, ~uch ~16 by u ing molding teGhn~ues ~nd plastic or other ~uit~ble ~ateri~l, or the various parts of portion 169 may be att~ched together. The ~upport portion 14 may be u~ed with celected sizes of lenses 12 ~nd ~lexible g~sket~ 14, ~nd de~igned ~o that the spherical center of curv~ture of e~ch lens 12 6ubstanti~11y coincides with the optical nodal point of ~ u6er'6 eye, or with the center of rotation of a user'~ eye, or ~all6 within a predetermined llcceptable zone of micalignment, ~6 de-scribed ~bove. Also, purge valve~ 126 may be u~ed in the 6upport portion 169 of FIG. 17 and portion 169 may ~ave a collecting area 128, li~e area 128 shown in FIG. 14.
It is intended that different sizes (or standard ~izes) of flexi~le ga~kets 14 may be ~elected ~nd used with the lenses 12 and support 169, and different ~izes (or ~t~ d sizes) of flexi~le g~kets 14 may be selected and used with the lenses 12 ~nd ~upport 169, so th~t the spherical center of c~r~ature of each lens 12 ~ubstantially coincides with the optical nodal point of a user's eye, or with the center of rotation of a user's eye, or falls within ~ predeter~ined accept~ble zone of ~i~lignment~ as described above.
It is important to note that the sizes of the flexible gasket 14, clamp 134 and fl~nge 136 may be chosen to fit or accommoA~te any desirable size lens 12. Nearsighted diver~
may use smaller size lenses 12. If desired, the diving mask 10 of FIGS. 13 through 17 may ~e used with the corrective lenses of FIGS. 7 through 9, and 18. ~ny combination of features disclosed in this application may be used for the diving ma~k 10. The hemispherically-shaped lenses 12 of the diving mask lo may be used with z full face mask, or a helmet which coverG the head of a diver. Al~o, ezlch lens of a diving mask may comprise only a small portion or segment of the hemispheriCallY-shaped lens 12. Therefore, the lenses of a conventional mask may be replaced by such small portion of lens 12.

FIG. 20 ~hows ~ti~l another e~bodiment o~ the diving mask 10 hav~ng hemisp~erically-~h~re~ ~n~e~ 12 mounted on the peripheral ~lange 174 of the ~upport portion 169 of the ma~k 10. Preferably, each one o~ ~he lenGe6 12 ha6 ~ bottom len~ 190 ~t t~e ~ottom of the lens 12. Ihe bottom lens 190 prefer~bly i~ integrally fo~med (~1~P~) ~c part of the lens 12. Alternatively, the ~v~ng m~c~ 10 may be m~nufactured with only one of $tc two l~nC~ 12 having the ~ottom lens 19~ . .
The lens 190 chown in FIG. 20 is a ~lat or plano-pl~no lens 192. ~ ~l~nge portion 194 ~ttaches the lens 190 to the larger lens 12, ~o that the flat ~urfaces of the lens 190 are perpendicular to a diver'~ line of ~ight represented by line 196 in FIG. 20. The lens 190 may extend ~ny des~rable distance or length along the bottom of the hemispherically-shaped lens 12. Al~o, if desired, the lens l90 ~ay conform with the contour or shape of lens 12. For example, lens 190 may ~e a portion or ~e~tion of A larger hemispherically-shaped lens.
The plano-plano flat lens 192 of FIG. 20 would provide a magnif ied image, or an image larger than the image ~een through the hemispherically-Rhaped lens 12. As a reRult, pres~yopic, or far~ighted diver~, who h~ve difficul~y focusing their eyes 24 close to the mask 10, may use the bottom lens l90 to inspect small object~ held close to the mask 10 under water, which will magnify the -cize of the objects.
Locating the bottom lenses 190 at the bottom of the hemispherically-shaped lense5 12 forms a collecting area 198, which aids in draining water toward the purge ~alvec 126. Furthermore, the collecting ~rea ~98 keeps water from flowing into the lenses 12 when a diver tilts his or her head in a downward direction in order to look straight down.
FIGS. 21 and 22 show how the bottom lens l90 may be mounted on the peripheral flange 174 using an O-ring seal 200 between the lens l90 and flan~e 174. An 0-ring seal 200 . 31 may ~150 be used at the top of the lens 12 ~etween the lens 12 and flAnge 174. However, any type of 6u~t~1e seAl may be used ~n place of the O-ring ~eal 200. rh~nnels or grooves 202 and 204 may be used in the lens 192 and flange 174, respectively, ~or ~he O-ring seal 200. If desired, ch~nPl 206 may be used in the flange 174 a~ ~hown in ~IG.
22. ~he lens 12 and bottom lens l90 may be ~ounted to the peripheral ~lange 174 using any ~uita~le clamping or fAstening means. Alternatively, O-ring ~e~ls 200 ~ay be omitted, and the lenses 12 and l90 may be attached to the flange 174 by adhesive, fusion of the partc, welding, or by any suitable means. Channels or grooves 202 ~nd 204 ~ay have any desirable ~hape or configuration such as rectangu-lar, concave, etc.
The diving mask 10 may ~150 be manu~Actured with bottom lenses lgO which may be used by nearsighted divers. Three ~uch bottom lenses 190 ~re shown in FIGS. 24, 25 and 30.
In FIG. 24, a convexo-concave lens 208 has ~n inside concave ~urface 212 and an outside convex surface 210, which yield a negative diopter value. The lens 208 may be used by nearsighted divers to see clearly when in or out of the water. The lens 208 may be ~astened to the lens 12 ~nd peripheral flange 174 by adhesive, fusion of the parts, welding, clamping, or by any suitable fastening means.
Alternatively, lens 208 may be integrally molded as part of lens 12.
The bottom lens 190 of FIG. 25 has-a pl~no-plano flat lens 192 and a plano-concave lens 214 (having an inside concave ~urface 216) fastened to the flat lens lg2. Any suitable means may be used to fasten the lenses 192 and 214 together, such as adhesive, fusion of the partc, welding, or the like. The combination of lenses 192 and 214 yields a negative diopter value, which allows nearsighted divers to see clearly throuyh the lens 190 of FIG. 25 when the di~ing mask 10 is being worn abo~e or below water.

Another bottom lens 190 used for the diving ~ask 10 ~s ~hown in FIG. 30 which allows di~ferent corrective lenses 216 with positive or negative diopter value~ to be ~e~o~bly Installed ln the bottom len~; 190. Flat len5 192 ~l~ 6 posi--tioning portions 218 ~t ~t8 inside flat 8urf~ce 220. Por-tions 218 ~ay be molded a~ part of lens 192, or ~ay be ~ttached to 6urface 220. A~ ~uch, portion~ 218 ~y be made out o~ a ~aterial ~uch as plast~c or gl2~5~, or ~ resilient material ~uch ~ rubber, neoprene, ~ilicone, or the like.
~ortions 218 ~re ~zed so that a gap or d~tance 226 will be maintained between ~urface 220 ~nd fl~t 6urface 222 of lens 216, resulting in a trapped space 226 when lens 216 is installed in bottom lens 190. In order to allow ~Yc~6~
fluid to e~cape as lens 216 i5 ~ns~alled, portionL~ 218 do not extend completely around or along ~h~n~ 198.
Correcti~e lens 216 has a groove 228 which extends around the periphery or perimeter of the lens 216. Corre-sponding grooves 230 and 232 exist in flange portion 194 and peripheral flange 174, respectively. A seal 234 fits in grooves 228, 232 ~nd 234, and is used to keep ~luid in trapped space 226, when lens 216 is installed in bottom lens 19, as descri~ed below.
The bottom lens 190 design of FIG. 30 allows a diver to conveniently and quickly install lens 216 in order to yield a desirable positive or negati~e diopter value for the lens 190. A plano-concave lens 216 with concave ~urface 224 i5 shown in FTG. 30. However, any desirA~le type len~; may be used for lens 216, ~uch as plano ovnvex lens, etc.
Space 226 i5 filled with fluid prior to installation of lens 2~6 in order to avoid a trapped air space between lenses 192 and 216. Snapping lens 216 into place in bottom lens 190 with a trapped air space will cause problems, because air compresses as a diver descends under water, and expands as the diver ascends. As the air ~Yr~n~, this may cause lens 216 to unseat or come loosr ~rom botto~ lens 190.
Also, trapped air may condense during di~ing, causing moisture ~ t-~ on lenses 192 and 216, which may result in ~ogging. Also, Newton r$ngs--or di~~raction line~ o~
interference--~ay occur due to d~fferences in pres~ure~
which could cause lenses 192 ~nd 216 to contact each other, making it di~ficult to see .through the bottom lens l90.
The above problems ~ay be ~olved by ~n~t~ n~ the lens 216, for example, in a bucket of di~t~ wAter. A d~er may ~imply u~e his or her finger~ to pu~h the correcti~e lens 216 into place in the bottom lens 190 ~o that seal 234 i8 engaged in groove6 228, 230 and 232, and t~e di~:tilled water fills the ~pace 226. Other ~uitable fluid may be used instead of the distilled water. The lens 216 may be r~moved from the bottom lens 190 using a suction-cup tool, .and replaced with another lens 216.
FIG. 23 6hows another ~o~ t of the di~ing m~sk 10, which may be used for farsighted or presbyopic di~ers. A
convexo-concave lens 236 with a positive diopter value is mounted inside the mask 10 for each lens 12 to either the peripheral flange 174 or support portion 169, or to ~oth these parts. Any ~uitable means may ~e used to mount the lens 236, such as adhesive, welding, fusion of the parts, clamping of the parts, etc. ~he lens 236 ha~ con~ex and concave ~urfaces 238 and 240, respectively, and may have any desirable positive diopter value to meet the needs of a diver. A bottom lens 190 may be used with the mask 10. The bottom of lens 236 i8 cut off, molded, or formed at 244, as chown in FIG. 23, so that a di~er's line of sight 196 throuyh the bottom lens 190 is not obstructed by the lens 236.
A diver cannot ~ee clearly above water t~rough lenses 12 when wearing the diving mask lo of FIG. 23 with positive diopter value lens 236. However, the plano-plano lens 192 or bottom lens 190 is a zero diopter lens abo~e water, which allows a diver to see clearly through lens 190 above water.
Locating the bottom lenses 190 ~t the bottom of the hemispherically-shaped lens 12 provides significant advan-t~ges. Prior to jumping into the water from a boat, ~ diver must be ~ble to glance down to ensure that no o~stacles or other di~ers ~re in the way. ~ wearing the diving ~ask 10, ~ diver m~y eA~ily look downward through the bottom 1~?nC~ l9O prior to ~umping into the water. Al~:o, while floating upright in the water ~nd 1Oo~n~ toward a boat or the ~hore, ~ diver typically tilts h~ or her heAd ~n backward direction to keep w~ter out of his or her mouth.
~ Clear ~ision ic provided through the bottom lense~ 190 of the d~ing mask 10 while the di~er tilts his or her head backward.
Water which has ~eeped into the diving mask -10 may enter air space 246 between convex surface 238 of lens 236 and inside ~urface 242 of the hemispherically-shaped lens 12. ~s a result, w~ter droplet~ may form on ~urfaces 238 and 242, causing optical di~tortion through the lenses 12 and 236.
~hi~; problem i5 ~;olved by the embodiment of~ the diving mask 10 shown in FIG. 29, having a m~mher 252 attached to each lens 236 near end 244 And to the lens 12 near fl~nge portion 194, 80 as to not obstruct a diver'~ line of ~:ight through bottom lens 190. Mem~ 252, lens 236 and lens 12 form a trapped dry-air space 248 inside the diving mask 10.
As a result, water is not Allowed to enter space 248, preventing moisture droplets from forming on ~ur~aces 238 and 242 and distorting the diver' 5 vision.
The trapped dry-Air space 248 provides important advantages. Space 248 causas the diving m~sk 10 to float, aiding retrieval of the masX when dropped or separated from a diver. As a result of the trapped dry-air space 248, the internal air volume of the diving mask lo is reduced, making it easier for a diver to clear the mask 10 of water ~hat has seeped into the mask 10. Also, dry-air space 248 reduces the amount of air volume required to compensate for hyper-baric pressure when descending under water.

~ IG. 28 shows yet another embodiment of the diving mask 10 having a transparent wall 250 of uniform thicknesl;, which forms trapped dry-a~r ~:pace 248. M~ ~ 252 i8 ~Ittached to merber 250 and to lens 12 neAr flA~nge portion 194. Wall 250 ~6 used for each lens 12, ~nd may be u5ed to ~y~OL L a positi~e diopter lens ~not shown), which ~y be ~tt~ched to wall 250 using ~ny ~uitable meAns such ~s adhesive~ fusion of part8, ~l~ring, welding, or the l~ke.
Note that the bottom len~es 190 of ~IGS. 23 through 25 ~nd 28 through 30 have collecting AreAs 198.
As chown in FIG. 26, the ends 253 of the hemispherically-shaped lenses 12 may be formed or curved toward a diver's head. Ends 253 decrease the external dimensions of the diving mask 10, r~ c;~ the inte~nal trapped-air volume of the mask 10. FGr~ed ends 253 w~ll only create minor distortion of vision in the most extreme 10 degree angle of view.
Another embodiment of the diving mask 10 i~ ~hown in FIG. 27. This em~odiment has a translucent baffle 251 attached near edge 20 where the hemispherically-shaped lenses 12 are joined. The baffle 2Sl is positioned ~arallel to a straight-ahead ~ield-of-view through ~he mask 10. The sides of the baffle 251 may be textured as represented by numeral 254, or may be coated by any ~uitable ~aterial, which will provide a translucent baffle that allows light to pass through the baffle, but not the detail of an image.
The translucent baffle 251 prevents double vi~ion ~-hic~;
occurG in the centermost stereoscopic field of view when large ~ize lenses 12 are used, and when t~e left eye 24 sees through the right lens 12, and the right eye 24 cees through the left lens 12.
A vast majority of di~ers currently wear contact lenses when u~ing their diving masks under water. There is a need for a diving mask lo that can be used to provide imp-oved viewing characteristics under water, and may be used by divers under water wh~le wearing contact lenses which correct eyesight ~bove water. Such a mask 10 could be U5ed by b~th a diver who does not need contacts or eyeglas~es, or by a diver who need6 corrective ~ ~c to see clearly ab3ve water.
S FIG. 31 schema~c~ y represents t~o generally r~lly-ch~rt~ c~ F-~ 256 used for ~nother ~rho~ent of the di~ing ~k 10, which would allow diverG
with 20-20 vision ~nd divers we~ring contact len5es to ~ee clearly under water. E~ch lens 256 has outer ~nd inner surfaces 258 and 260~ respectively, having different curvatures. A ~chematic repre~ent~tion of two other generally hpm~cpherica~ly-~h~rt~ meniscus lenses 262 uSed for still another embodiment of the diving mask 10 i5 shown in FIG. 32. Each lens 2G2 also has outer and inner ~urfaces 258 and 266, respectively, having di~ferent curvatures.
Note that lenses 256 and 262 have the ~ame out~ide ~urfaces 258. The lenses 262 may also be used in a diving mask 10, which can be used under water by divers with 20-20 vision and divers wearing contact lenses.
The curvatures of outer surface 258 and inner surf~ces 260 and 266 of the lenses 256 and 262 are sized to yield an effective zero diopter value under water. As a result, a diver with 20-20 vision, or vision corrected by contact lenses, may then use the diving mask 10 to ~ee clearly under water. Lenses 256 and 262 are designed hy first selecting an outer surface 258 o~ a particular curvature, and then varying the curvature of the inner surfaces 260 ~nd 266 to yield lenses 256 and 26Z having a zero diopter value under water.
FIG. 34 is a schematic representation of meniscus lenses 256 and 262. The 5pherical centers of curvature 268 and 270 of the outer and inner ~urfaces 258 and 260, respectively, of lens 256 ~re coplanar, or fall on a plane 271 passing through the center 272 of a diver'c eye 24. For practical purposes, the center of an eye 24 may be consid-ered to ~e the center of rotation 150 of the eye 24. Also, .

the ~pherical centers of curvature 268 ~nd 270 are located - diRtances 274 and 276, respectlvely, ~h~nd the center 272 of eye 24. A~; a result, lens 256 i5 loc~ted closer to a diver' 6 face 16. Th~R effecti~ely r~ G~ the tr~pped air S volu~e inside the diving mas~ 10 And the ~ize of the mask 10 .
The spherical center~ of curvature 268 and 2~8 of the outer and inner Rurface6 258 ~nd 266, respectively, of ienR
262 ~re not coplanar, or do not fall on a plane 271 passing through the center 272 of a diver'~ eye 24. The ~pherical center of curvature 278 of ~nner surface 266 i6 located a distance 180 behind the center 272 of eye 24. Al~o, note that spherical center of curvature 278 of inner surface 266 i6 off~et a distance 281 from center of curvature 270 of the inner surface 260, such that line 283, passing through center6 268 and 278 forms an angle 285 with line 271.
Preferably, angle 285 has a range of from ~bout zero degrees to about 15 degrees. However, angle 285 may have any desired value.
Surfaces 284 and 286 o~ lenses 256 and 262, re~pective-ly, may ~e textured or coated with any suitable material to provide a translucent effect in order to prevent double vision, ~s explained above.
Meniscus lens 256 has a thickness 264 that is larger than the ~x;mum thickness 282 of ~eniscus lens 262. As a result, lens 262 is lighter than lens 256. The curvature of insi~e ~urface 266 of lens 262 c~uses a ~light degree of coma, or a sliyht distortion where ~ fringe is ~,~duced, for perip~eral vision. However, such coma effect is so minim~l to almost be imperceptible.
For an outer ~urface 258 diameter of 5.5 inches, the thickness 264 of lens 256 is about 20 mm, and the thickness of lens 262 is about 16.3 mm. The radius of inner surface 260 is about 120 ~m, ~nd the r~dius of inner surface 266 is ab~ut 126 mm.

The main curvatures of surfaces 260 ~nd 266 ~re ~1FO
chosen (desi~ned) so t~at the lenses 256 And 262 prOV~de increased peripheral ~sion. Note in FIG. 34 that the intersection o~ outer ~urfAce 258 And ~nner ~urfAce 260 of S lens 256 at 288 ~8 ~lightly above a line 292 pa5s~ng in front o~ the eyes 24 ~or cornea~) of ~ di~er. Al~o, the inter~ection of outer ~urface 258 and ~nner ~ur~ace 266 of lens 262 At 290 Approximately f~lls on line 290, providing opt~mal peripher~ ion. It i~ the intention of the invention to provide increased peripheral vi5ion for the diving mask 10. The lenses 256 and 262 preferably provide in-focus peripheral vision in a range of from about 90 degrees to about 180 degre~s.
It is the intention of thi~ invention to provide a diving mask 10 using the meniscus lens 2S6 or 262, which ~urnishes optimal peripheral vision and decreased trapped air space inside the ~ask, while ~till furn~hing clearances for a diver'~ face. The meni~cus ~enses 256 and 262 des~ribed above, having an outside surface 258 with a 5.5 inch diameter furnishes the above-mentioned advantages.
FIG. 33 ~chematically illus~rates how changes in the effective diopter value of the meniscus lens 256 tor 262) can be matched with the type of bottom lens 190 used for the diving mask lo. For a meniscus lens 256 yielding a zero diopter value under water, a plano-plano bottom lens 290 would be needed. For ~ meniscus lens 256 having ~ positive diopter value under water, a plano-convex bottom lens 190 would be used ~or the diving mask 10. A plano-concave bottom lens 190 would be required for a meniscus lens 256 yielding a negative diopter value under water.
The lenses 256 and 262 are designed so that the centers of spherical curvature 294 of the outside and inside surfaces 258, 260 and 266 of the lenses are located ~elow the centers 272 of a diver's eye 24, when the lenses are viewed vertically as sh~wn in FIG. 33. Center 294 repre-sents either of the centers 268, 270 and 2~8 shown in FIG.

34. ~ocating center 294 below center 272 o~ the eye results in reduced weight for the lense~ 256 ~nd 262 becau5e the thicker port~ on of the l~nr?~ i8 located near the bottom lens 190, ~nd i~ reduced ~n size to form bottom lens 190.
A160, ~C di~cussed below, dr~inage iE; im~-~ve~ due to loc~ting center 294 below the center 272 of the eye 24.
F:~GS. 3~ through 38 ~how a ~G~ L portion 169, perimeter clamp 296 and c~"~ l flexible face ceai 298 of ~not}~er em}:odiment of the di~ring mask 1Ø ~ e ~ OLL
portion has a peripheral ~lange 174 for ~ounting ~ pair of hemispherically-shaped lenses 12 (which may be meniscus lenses), ~nd two integral housings 300 used for mo~nting purge valve 126 (see FIG. 38).
Ac best shcwn in FIGS. 36 and 38, ~n opening 302 is ~ormed in support portion 169 which allows water to drain from inside the mask 10 through purge valve 126. A diver may exhale, forcing the water through opening 302 and out of the mask through purge valve 126. The purge valve 126 i5 angled to direct air bubbles away from the diver's field of view toward the back of the mack lo. The support portion 169 has one integral housing 300 for each lens 12, i.e., two pur~e valves are used with the mask 25 shown in FIGS. 36 and 37.
FIG. 45 shows another embodiment of the diving mas~ 10 using a peri~eter clamp 304 having integral housings 306 formed in the clamp for the purpose of mounting purge valves 126. The perimeter clamp 296 serves the dual functions of mounting the ~ace seal 298 to the ~upport portion 169, and mounting the lenses 12, including the bottom lenses 190, to the support portion.
- The perimeter clamp 296 ~ay be a ~ezel clamp and is used to clamp the face seal 298 to the support portion 169.
~he perimeter clamp 304 and support portion 169 have grooves 308 and 310, respectively, which engage extensions 312 integrally formed in the face seal 298. As shown in FIG.
4~, the support portion 169, face seal 298, and peri~eter W O 96/41229 PCT~US96/09389 clamp 304 are generally formed to engage each other. These parts can be ~ormed in any des~rable manner in order to engage each other. Preferably, clamp 304 has a flange portion 314 which engages a fl~nge portion 316 of the bottom lens 190.
Pre~erably, one of the hou~inys 306 ~s used for each lens 12 of the mask. ~ described above, the housings are ~ngled to direct air bubbles ~way from the diver's field of - view toward the back of the mask 10.
FIGS. 39 through 44 ~:how two generally hemi~pherically-shaped ~en;C~ lenses 262 of the diving mask 10. Note that each lens 262 has an integrally formed bottom lens 190. Bottom lens 190 may be a portion or segment of a larger hemispherically-shaped lens. However, lens 190 may have any other desirable shape, as explained above, e.g., plano-plano, plano-convexo, etc. Note that the top 318 of the pair of lenses 262 is formed to fit the support portion 169 of the mask 10. ~owever, top portion 318 may have any desirable shape. The bottom lenses 190 are formed to provide collectiny areas 198 for draining water inside the mask.
As di~cussed above in connection with FIG. 33, the spherical centers of cur~ature 268 ~nd 278 of the lenses 262 are located below the centers 272 of a diver's eyes. As best ill~strated in FIG. 44, this locates the thicker portions of the lenses 262 near the collecting areas 198, and helps to reduce the weight of the lenses. Also, because the thicker portions of t~e lenses 262 are located near areas 198, thiG facilitates drainage into the collecting areas.
As explained above, surfaces 2~6 may be textured or coated to provide translucent surfaces in order to prevent double ~ision.

CA 02223~26 1997-12-04 wo 96/41229 pcT/uss6/os38s Meniscus lenses may be used for the di~ring mask instead of lenses 262, described above.
When the user is under water, the diving mask lO
described herF;nAho~re provides optimum ~riewiny 5 characteristics underwater. Eowever, when the user raises hi~; or her head ~nd the diving mask lO above water, the primary meniscus lenses described her~ hove yield ~ very ~L~v~y positive diopter effect, which inhibits Yision beyond a range of approximately eighteen ~nches. ~IG. 46 10 presents a top plan view of a ~;ingle ~upplemental lens 300 which attaches to the diving mask lO for purposes of providing the user with clear ~rision when the user raises his or her head above water. The two hemispherically-shaped meniscus lenses 301 having different inner and outer 15 radii of cur~rature are described herei~Phove in reference to FIGS. 23-44. The supplemental lens 300 is formed of a thin--walled transparent material having zero power. once the diver enters the water, the cavity 304 fills with water and provides the diver with the beneficial aspects of the 20 diving mask lO described hereinabove, specifically the elimination of underwater magnification--distortion caused by the differences in refractive indices of water and air.
The diver views an image through the hemisptlerically-~h~re~
lenses 301, the water filled ca~rity 304, and the 25 supplemental lens 300, and the ambient water outside the supplemental lens 300. As the supplemental lens 300 is constructed of a transparent material providing zero power, no optical distortion occurs. When under water, the thin walls of the transparent supplemental lens 300 are 30 effectively invisible, yielding no power and no distortion.
The supplemental lens 300 may be constructed o~ a different glass or plastic material than the hemispherically--shaped lenses 301 so that the supplemental lenses 300 may be replaced when scratches or other abrasions occur. The 35 preferred material for the supplemental lens 300 is acrylic, but any material which is relatively transparent in water may be used. Acrylic provides the additional W O 96/41229 PCT~US96/09389 benefit of being transparent to scratches and abrasions when underwater, as such imperfections tend to fill with water and become practically imperceptible.
The ~upplemental lens may be joined to the diving mask 10 by any conventional engagement means, sUCh as clips, a ridge ~,o~ n~ the supplemental lens and a cOrresponding receiving channel within the di~ing mask 10, or any other suitable m~n~ for joining plastic ~mhe~ ~nd concurrently providing a water tight ~eal. The ~upplemental lens 300 may al~o be permanently affixed to the diving mask 10 by epoxy or other permanent adhesive, a molded bar surrounding the periphery of the supplemental lens, or some other commonly known permanent joining methods.
When the supple~ental lens 300 is joined to the mask 10, cavity 304 is formed and water may be stored therein.
Storage of water in cavity 304 provides the beneficial dioptric effect missing when the diver 5urfaces and uses the diving mask 10 out of water.
Both left supplemental lens 305 and right supplemental lens 303 are formed to approximately conform with the curvature of the left and riyht portions of the outer radius of both hemispherically-~haped lenses 301, respectively. This curvature of the supplemental lens -300 preserves the hydrodynamic shape of the diving mask lo.
Center ~uppleme~tal lenses 302 are curved to provide zero power in conjunction with water filling the cavity 304 and dependant on the refraction of water, the thickness of the center supplemental lenses 302, the radii of the outer edge of the hemispherically-shaped lenses 301 and the inner edge of center supplemental lenses 302, which relate to the size of cavity 304. The curvature of the center supplemental lenses is determined by the standard len~m~ker formula. To produce the required dioptric effect above water using this standard lensmaker formula, the center supplemental lenses 302 are tilted slightly inward.
Cavity 304 may be filled using various means. As shown in FIG. 46, the preferred embodiment consists of a CA 02223~26 1997-12-04 water-tight cork 306 used in connection with hole 307 in supplemental lens 300. Any co~mnnly known flexi~le water_ tight material may ~e used ~or cork 306. The user initially removes cork 306 from hole 307 and fill5 cavity 304 with water through hole 307. Alternately, a hole and cork may be located within hemi~pherically-shaped lenses 301 and the cavity 304 filled from the inside of the diving mask 10.
FIG. 47 ~hows the ~upplemental lens 300 having a curved upper portion 308 ~nd a curved l~wer portion 309 substantially parallel to the cur~ature of the outer edge of hemispherically-shaped lens 301, again to provide a beneficial hydrodynamic effect. An alternate means for filling cavity 304 is to provide an opening between curved upper portion 308 and hemispherically-shaped lens 301.
Such an arrangement provides a cupping effect for a user raising his or her head above water, but may serve to collect turbid water in cavity 304 and obstruct both underwater and above water vision.
FIG. 48 illustrates a pair of hemispherically-shaped meniscus lenses 301 having visual gaps 320 and 321. The visual gaps 320 and 321 typically consist of ~ections of contoured portion 46 of diving mask 10, inhibiting the peripheral vision of the diver and providing an approximately 160 degree horizontal field of view. The division between the visual horizontal peripheral line 325 perpendicular to the optical nodal point of each corresponding eye 24 of the user is appr~ximately ten degrees on each side. In order to provide 180 degree visibility to the user, additional side lenses are incorporated into diving mask 10.
FIG. 49 illustrates two side wall lenses 351 and 355.
Outer side w211 lens edge 352 continues the curvature of - the outer edge of hemispherically-shaped lenses 301 and inner side wall lens 353 runs substantially parallel to outer side wall lens 352 and adjoins hemispherically-shaped lenses 301 at first joint 354. These side wall lenses 353 and 35~ provide a zero power wall within ten degree Visual gaps 320 and 321. A user viewing an object through the lens configuration shown in FIG. 49 would 5ee a 180 degree field of view, however the outermo~t field-of-view through S the ~ide wall lenses 353 and 355 would be out of focus, since underwater this lens configuration would yield a negative dioptric effect. ~lthough the configuration is out of focus, the lens con~iguration produces no fragmentation of objects viewed through the ~ide wall lenses 353 and 35~.
FIG. 50 illustrates an alternate em~o~iment of the meniscus lens and ~ide wall lens configuration ~hown in FIG. 49. The hemispherically-shaped lenses 301 have affixed thereto a pair of ~nh~n~ focus ~ide wall lenses 1~ 356 and 360. The enhanced focus side wall lenses have an outer surface 357 and an inner surface 358 formed to constitute a secondary meniscus lens which i~ G~es focusing at the outermost point~i of the user's field of vision. The inner surface 358 adjoins the hemispherically shaped lenses 301 at edge 359.
Any suitable optical material may be used for the lenses 12, 256, 262, and 301, such as polycarbonate, glass, or any other refractive material. Any parts or features of the diving mask 10 described above may be used in combination with any other parts.
The above description discloses the preferred embodiments of the present invention. However, persons of ordinary skill in the art are capable of numerous modifications once taught these principles. Accordingly, it will be understood by those 5killed in the art that changes in form and details may be made to the above-detailed embodiments without departing from the spirit and scope of the invention.

Claims (37)

I CLAIM:

1. A method of fabricating a diving mask comprising the steps of:
forming two hemispherically-shaped lenses;
mounting said lenses on a flexible portion; and forming at least one supplemental lens to engage said diving mask and form a cavity between said diving mask and each supplemental lens, wherein said cavity may be filled with and hold liquid.

2. [CANCELLED]

3. An underwater diving mask comprising:
a flexible gasket;
two generally hemispherically-shaped lenses mounted on said flexible gasket;
means for releasably securing said diving mask to a face of a user, said hemispherically-shaped lenses being mounted on said flexible gasket; and side walls continuing from said hemispherically-shaped lenses, said side walls extending from said hemispherically-shaped lenses to a visual horizontal peripheral line approximately perpendicular to the optical nodal point of each corresponding eye of said user's face.

4. The diving mask of Claim 3 further comprising retractable corrective lenses mounted to said diving mask.

5. The diving mask of Claim 3 further comprising a supplemental lens that engages said diving mask forming a cavity between said diving mask and said supplemental lens.

6. The diving mask of Claim 5 further comprising a hole and stopping mechanism located in said hemispherically-shaped lenses.

7. The diving mask of Claim 5 further comprising a hole and stopping mechanism located in said supplemental lens.

8. [CANCELLED]

9. The diving mask of Claim 3 wherein each of said side wall lenses extend from approximately ten degrees to approximately zero degrees from said visual peripheral line.

10. The diving mask of Claim 3 wherein said side wall lenses comprise:
an outer radius continuing the curvature of the outside of said hemispherically-shaped lenses; and an inner edge extending from the inside of said inner lens and substantially parallel to said outer radius, wherein said side wall lenses maintain generally uniform thickness.

11. The diving mask of Claim 10 wherein said side wall lenses and hemispherically-shaped lenses are shaped to substantially fit said contours of said user's face using laser scanning techniques.

12. The diving mask of Claim 3 wherein said side wall lenses comprise:
an outer radius continuing the curvature of the outside of said hemispherically-shaped lenses; and an inner edge extending from the inside of said inner lens and away from the inside of the inner lens, wherein said side wall lenses provide a secondary meniscus lens thereby improving focusing characteristics at edges of the user's horizontal field of view.

13. The diving mask of Claim 12 wherein said side wall lenses and hemispherically-shaped lenses are shaped to substantially fit said contours of said user's face using laser scanning techniques.

14. The diving mask of Claim 3 further comprising at least one purge valve located in said diving mask.

15. An underwater diving mask comprising:
a lens;
means for mounting said lens on a face of a user;
and a supplemental lens mounted proximate said lens forming a cavity between said lens and said supplemental lens.

16. The diving mask of Claim 15 further comprising retractable corrective lenses mounted to said diving mask.

17. [CANCELLED]

18. The diving mask of Claim 15 further comprising side wall lenses continuing from said hemispherically-shaped lenses, said side wall lenses extending from said hemispherically-shaped lenses to a visual horizontal peripheral line approximately perpendicular to the optical nodal point of each corresponding eye of said user's face.

19. The diving mask of Claim 18 wherein each of said side wall lenses extend from approximately ten degrees to approximately zero degrees from said visual peripheral line.

20. An underwater diving mask comprising:
a flexible gasket;
two generally hemispherically-shaped lenses mounted on said flexible gasket;
means for releasably securing said diving mask to a face of a user; and at least one purge valve located in said diving mask so that bubbles formed when water is expelled from said mask pass away from a field of vision of said user.

21. The diving mask of Claim 20 further comprising retractable corrective lenses mounted to said diving mask.

22. The diving mask of Claim 20 further comprising a supplemental lens that engages said diving mask forming a cavity between said diving mask and said supplemental lens.

23. The diving mask of Claim 20 further comprising side wall lenses continuing from said hemispherically-shaped lenses, said side wall lenses extending from said hemispherically-shaped lenses to a visual horizontal peripheral line approximately perpendicular to the optical nodal point of each corresponding eye of said user's face.

24. The diving mask of Claim 23 wherein each of said side wall lenses extend from approximately ten degrees to approximately zero degrees from said visual peripheral line.

25. The diving mask of Claim 23 wherein one of said lenses has a collecting area, said at least one purge valve being located in said collecting area.

26. A method of fabricating a diving mask comprising the steps of:
selecting two hemispherically-shaped lenses of a predetermined size;
selecting a flexible gasket of a predetermined size to fit a user's face;
selecting a support portion of a predetermined size;
attaching said support portion to said flexible gasket;
mounting said lenses on said support portion;
selecting at least one supplemental lens to engage said diving mask and form a cavity between said diving mask and each supplemental lens; and mounting said supplemental lens on said diving mask so that liquid may be situated within said cavity.

27. [CANCELLED]

28. An underwater diving mask comprising:
two generally hemispherically-shaped lenses;
a translucent baffle attached to said lenses; and means for mounting said lenses on a face of a user so that a spherical center of curvature of each of said lenses substantially coincides with a corresponding eye of said user.

29. The diving mask of Claim 28 further comprising a supplemental lens that engages said diving mask forming a cavity between said diving mask and said supplemental lens.

30. The diving mask of Claim 28 further comprising side wall lenses continuing from said hemispherically-shaped lenses, said side wall lenses extending from said hemispherically-shaped lenses to a visual horizontal peripheral line approximately perpendicular to the optical nodal point of each corresponding eye of said user's face.

31. An underwater diving mask comprising:
two generally hemispherically-shaped meniscus lenses designed to provide a zero diopter value under water, each of said lenses providing an in-focus peripheral vision of more than 90 degrees;
means for mounting said lenses on a face of a user;
and side wall lenses continuing from said hemispherically-shaped lenses, said side walls extending from said hemispherically-shaped lenses to a visual horizontal peripheral line approximately perpendicular to the optical nodal point of each corresponding eye of said user's face.

32. The diving mask of Claim 31 further comprising a supplemental lens that engages said diving mask forming a cavity between said diving mask and said supplemental lens.

33. [CANCELLED]

34. The diving mask of Claim 31 wherein each of said lenses has inner and outer surfaces of different curvature.

35. An underwater dive mask comprising:
a lens arrangement comprising at least one lens having a viewing area including a lower edge;
at least one offcenter mounted purge valve affixed adjacent the viewing area of said lens arrangement; and means for mounting said lens arrangement on a face of a user.

36. The diving mask of Claim 35 wherein said lens arrangement comprises at least one hemispherically-shaped lens.

37. The diving mask of Claim 35 wherein said mask comprises two purge valves, with one purge valve located in each lens.