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Publication numberUS3702930 A
Publication typeGrant
Publication dateNov 14, 1972
Filing dateMar 12, 1971
Priority dateMar 12, 1971
Also published asDE2212438A1
Publication numberUS 3702930 A, US 3702930A, US-A-3702930, US3702930 A, US3702930A
InventorsJoel Henry G
Original AssigneeOlivetti & Co Spa
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Remote illuminating apparatus
US 3702930 A
Abstract
A system for efficiently projecting the light from a point or line light source to a specified area in a remote object plane. Two separate families of concentrically disposed ellipses are positioned to share a common focus and to have the other focus of each ellipse family disposed on the remote object plane, so that the distance between the two focuses on the object plane defines the area on the plane to be illuminated. The light source is placed at the common focus of the two families of ellipses, and elliptical reflecting segments from the two families of ellipses are disposed about the light source to direct the light from the light source to the defined area on the object plane. Proper orientation of the elliptical reflecting segments allows for all of the light from the light source to pass to the designated area on the object plane in one or less reflections against the elliptical reflecting segments.
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Description  (OCR text may contain errors)

Joel

REMOTE ILLUMINATING APPARATUS [72] Inventor: Henry G. Joel, New York, NY.

[73] Assignee: Ing. C. Olivetti & C., S.p.A., Ivrea,

' Italy 221 Filed: March 12, 1971 [21 Appl. No.: 123,504

[52] US. Cl. ..240/4L35 R, 240/103 R [51] Int. Cl ..F2lv 7/00 [58] Field of Search ..240/41.35 R, 41.36, 41.37, 240/41.35 C, 41.35 F, 78 LD, 103 R;

[56] References Cited 7 UNITED STATES PATENTS 2,297,124 9/1942 Anderson et al. .....240/78 LD 2,673,288 3/1954 Stevens et a] ..240/41.36

3,283,142 11/1966 Freeman ..240/4l.35 R

3,449,561 6/1969 Basil et a1 ..240/4l.35 R

1,757,527 5/1930 Henningsen ..240/103 R 1,679,108 7/1928 Wood ..240/41.37

3,112,893 12/1963 Crosby et al ..240/41.36

FOREIGN PATENTS OR APPLICATIONS 703,009 2/1931 France ..240/41.35 C

[ Nov. 14, 1972 265,177 12/1927 Great Britain ..240/4136 404,540 1/1934 Great Britain ..240/41.35 533,135 11/1954 Belgium ..240/4l.36

Primary Examiner-Samuel S. Matthews Assistant Examiner-Alan A. Mathews Attorney-Kevin McMahon ABSTRACT A system for efficiently projecting the light from a point or line light source to a specified area in a remote object plane. Two separate families of concentrically disposed ellipses are positioned to share a common focus and to have the other focus of each ellipse family disposed on the remote object plane, so that the distance between the two focuses on the object plane defines the area on the plane to be illuminated. The light source is placed at the common focus of the two families of ellipses, and elliptical reflecting segments from the two families of ellipses are disposed about the light source to direct the light from the light source to the defined area on the object plane. Proper orientation of the elliptical reflecting segments allows for all of the light from the light source to pass to the designated area on the object plane in one or less reflections against the elliptical reflecting segments.

10 Claim, 7 Drawing Figures PAIENTEMM 14 m2 3.702.930

' SHEET 3 HF 4 I 84 I if Q4 0 INVENTOR s/vey Ja'zz.

ATTORNEY REMOTE ILLUMINATING APPARATUS BACKGROUND OF THE INVENTION 1'. Field of the Invention This invention relates to illuminating systems and, more particularly, to a system to collect the maximum amount of available light from alight source and efficiently direct this light on a remote object plane with a minimum number of reflectionsfrom the light source 1 light source and the illuminated object plane increases.

This is due to the inherent reflectivity characteristics of the reflecting surfaces and, additionally, to dirt which is bound to lodge or accumulate on the reflecting surfaces.

In order to minimize the reflectivity losses, many devices have minimized the number of reflections in the light path from the light source to the object plane by providing reflective housings about the light source which extend close to or even contact the object plane to be illuminated by the light. While these types of devices do allow for a minimum of reflections in the light path, their usefulness is limited because of the close proximity of the apparatus to the object plane to be illuminated.

Additionally, many of the prior art illuminating devices require large numbers of reflecting surfaces which are either intricately shaped or which must be carefully assembled and aligned, or both, in order to effectively function. These devices are, therefore, rela tively costly and fairly delicate.

SUMMARY'OF THE INVENTION In order to overcome the problems set forth in the prior art, the present invention sets forth an apparatus for capturing and projecting light from a point or line light source to a remote object plane. Elliptical reflecting segments which are disposed about the light source and are disposed remotely from the object plane direct the light from the light source to the object plane with one or less reflections in the light path. The elliptical reflecting segments are from two or more separate families of concentric ellipses which families are positioned with relation to each other so as to share a common focus. The other focus of each of the elliptical families is disposed on the object plane, and the maximum distance between these two focuses defines the area on the object plane to be illuminated. Elliptical reflecting segments from each family of ellipses are used in alternate sections about the light source to avoid interference between the reflecting segments of one quadrant and the light paths reflected from reflecting segments in an adjacent quadrant.

Accordingly, in view of the above, it is an object of the present invention to set forth a system for efficiently directing the maximum available light from a light source to an object plane to be illuminated.

Another object of the present invention is to provide a system for efficiently directing light from a source to an object plane to be illuminated which plane is remote from the light source. I

It is still another object of the present invention to provide a system for directing the light from a light 0 source to a remote object plane to be illuminated which system requires one or less reflections in the light path.

Yet another object of the present invention is to provide a system for directing the light from a light source to a remote object plane to be illuminated which system can be cheaply and easily fabricated.

It is a further object of the present invention to provide a system for directing the light from a light source to a remote object plane to be illuminated. which system is reliable in operation.

Another object of the present. invention is to provide a system for directing the light from a light source to a remote object plane to be illuminated which does not require delicate adjustment.

It is still another object of the present invention to provide a system for efficiently directing the light from a light source to a pre-defined area on a remote object v plane.

Other objects and advantages will be apparent from the following description of an embodiment of the invention and the novel features will be particularly pointed out hereinafter in connection with the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a family of concentrically disposed ellipses illustrating the various reflective paths from one common focus of the ellipses to the other common focus of the ellipses.

FIG. 2 is a schematic view showing two separate ellipses sharing a common focus and having the other focus of each ellipse in spaced relation to each other.

FIG. 3 is a schematic representationof elliptical reflecting segments disposed about a light source to direct light to a remote object plane, in accordance with the teachings of thepresent invention.

FIG. 4 is an enlarged view of a section of FIG. 3 showing the reflection of the light path against the reflecting segments as the light travels from the source to the remote object.

FIG. 5 is an embodiment of the invention in which the elliptical reflecting segments are connected to form a closed structure.

FIG. 6 is an enlarged view of a portion of FIG. 5 showing the light path within the structure.

FIG. 7 isanother embodiment of the invention showing the elliptical reflecting segments positioned in a mounting device.

. DESCRIPTION OF THE PREFERRED EIVIBODIMENT:

FIG. '1 shows a family of three concentrically disposed ellipses, generally indicated at l0, l2 and 14 respectively for the thinner to wider ellipses, having lower and upper common focuses l6 and 18. It is well known that within any given closed ellipse, all lines radiating from one focus will reflect off the walls of the ellipse and converge at the other focus of the ellipse. Therefore, if the lower focus 16 were a light source, then within any of the concentric ellipses, all of the light from focus source 16 would be received at the upper receiving focus 18.

It is not practical to use a single, simple ellipse to direct all the light from a source to a receptacle, because it would be necessary to enclose both the source and the receptacle within the closed ellipse. However, it is-possible to arrange various segments of concentric ellipses to catch the light fromthe common focus light source 16 and reflect it back to the common receiving focus 18.

As shown in FIG. 1, elliptical segments 20, 22 and 24 respectively of ellipses 10, 12 and 14, are positioned with relation to each other so that no light from source 16 passes between the elliptical segments, and they reflect all of the light back to receiving focus 18 without blocking the light reflected from each other. Reflector element 20 will reflect all of thelight in angle 26 from source 16, while elements 22 and 24 will likewise respectively reflect thelight in angles 28 and 30 to source 16. Thus, it can be seen that by properly arranging additional elliptical segments from other concentric ellipses (not shown), all of the light radiating forward from source focus 16 could be reflected back to receiving focus 18. i

This same principle of coacting elliptical segments also applies for reflecting the light radiating rearwardly from source focus 16. Since all of the figures are symmetrical about a center line, for purposes of simplicity, itemsto the left of the center line will be distinguished from similar items to the right of the center line by using a prime symbol with the designating numbers.

As seen in FIG. 1, elliptical segments 32 and 34 on ellipses 12 and'14 respectively reflect the light radiating rearwardly from source 16 in angles 36' and 38' respectively, to receiving focus 18. Therefore, as was the case previously, by arranging additional elliptical segments from other concentric ellipses, all of the light radiating rearward from source focus 16 would be reflected back to receiving focus 18.

Unfortunately, in a single family of concentrically disposed ellipses, the elliptical segments reflecting rearward radiating light cannot be combined with the elliptical segments reflecting forward radiating light to project all of the light from the common source focus to the common receiving'focus. The elliptical segments reflecting the forward radiating light would interfere with the elliptical segments reflecting the rearward radiating light. For example, as seen in FIG. 1, the light path from elliptical segment 34 would be at least partially blocked by elliptical segment 20.

The problem of interference between the elliptical reflecting segments for forward and rearward radiating light can be overcome by using two or more separate concentric families of ellipses which are disposed with relation to each other with a common source focus for all families of ellipses and separate receiving focuses for separate families of ellipses as, for example, in the manner shown in FIG. 2.

FIG. 2 shows two identical ellipses 40 and 42 which are disposed with relation to each other so that the lower focus 16 of each family of ellipses coincide and so that the upper focuses 18 and 18' of ellipses 40 and 42 respectively are in spaced relation to each other. Ellipses 40 and 42 can be classified as right and left ellipses respectively. Because all lines emanating from the one focus of an ellipse will reflect against the walls of the ellipse and pass through the other focus of the ellipse, as previously mentioned, elliptical segment 44 of ellipse 42 will reflect light from source focus 16 to lefthand receiving focus 18, while elliptical segment 46 on righthand ellipse 40 will reflect light from source focus 16 to righthand receiving focus l8.

Because of the relative orientation of the right and left hand ellipses 40 and 42, the upper elliptical segments of one ellipse reflecting forward radiating light from the common source would tend to provide less of an interfering surface to the pathway of light reflected from the lower elliptical segments of the other ellipses which reflect the rearward radiating light from the common source. Proper orientation of the ellipses and the elliptical segments can, therefore, reduce and even eliminate the interference between the rearward light reflecting segments and the forward light reflecting segments, as shown in FIGS. 3 and 4.

' ing focus 18', while rearward light reflecting elliptical segments 49, 51, 53, 55, 57 and 59 are segments of a righthand family of ellipses and reflect light to receiving focus 18. Similarly, elliptical segments 48', 50', 52', 54', 56, 58' and 60' will reflect light to focus 18 while elliptical segments 49, 51', 53', 55', 57' and 59' reflect light to focus 18'. Section 62 directly behind source 16, extends on either side of the center line. It can be formed from two elliptical segments focusing on 18 and 18 or it can be a circular section which would reflect light to the area between the two focuses. Elliptical sections 59 and 60 and their corresponding prime sections are shown as being formed from a single. member, although this need not be the case for proper functioning of the invention. 3 v

In FIG. 4, we see right focus rear elliptical segments 49, 50, 53 and 55 and left focus front elliptical segments 48, 50, 52, 54 and 56. As a typical example of the interaction between the forward and rearward elliptical segments, we see that all the forward radiating light in angles 64, 66, 68 and 70 will be reflected by segments 50, 52, 54 and 56 respectively to receiving focus 18'. Similarly, all the rearward radiating light in angles 63, 65, 67 and 69 will be reflected by segments 49, 51, 53 and 55 respectively to receiving focus 18; Note that angles of light 71, 73, and 77 reflected by elliptical segments 49, 51, 53 and 55 respectively do not contact the back surfaces or the front edges of the forward elliptical segments, but instead have clear pathways through the adjacent upper elliptical segments to the right receiving focus 18. The same would be true for the angles of reflection 71, 73, 75, 77 (not shown) which are the symmetrical counterparts of angles of reflection shown in FIG. 4.

From the above discussion, it should be apparent that the arrangement of elliptical reflecting segments provides an extremely efficient method for capturing and directing all of the light from a point or a line source to a remote object plane to be illuminated. This device can be effectively used in many various applications. For example, as shown in FIG. 5, an entire unit can be manufactured for use as a directional light source. Forward reflecting elliptical segments 76, 78, 80, 82, 84, 86 and 88 and rearward light reflecting elliptical segments 90, 92, 94, 96 and 98, and the corresponding prime elements to the left of the center line, can be enveloped in a clear plastic or glass material 100 which connects the various elliptical segments. I

As shown in FIG. 6, this apparatus would work exactly as that described previously with the possibleexception that there may be slight changes in the direction of the light as the light leaves the clear transparent areas 100, which connect the elliptical reflecting surfaces. However, depending upon the material used, the index of refraction and various other factors, the required positioning of the elements for proper functioning of the apparatus can be determined.

FIG. 7 shows another embodiment of the illuminating system. The system consists essentially of a line source light bulb indicated at 102 which is mounted into an end plate 104. Grooves which correspond to the elliptical segments shown in FIGS. 3 and 4 are machined in the end plate. Thin sheets of reflecting material, such as thin aluminum sheets, etc., are then placed into the grooves in end block 104 to act as reflectors. The flexibility of the thin sheets allows each of them to fit into the designated elliptical groove and conform to the shape of the groove, thereby forming the elliptical segment desired for proper operation of the system. These segments are identified inFlG. 7 similarly to the elliptical segments shown in FIG. 5. The light emanating from focal source 16 will then be directed with one or less reflections to the area 106 to be illuminated on a remotely disposed object plane 108, which area is designated by receiving focuses 18, and 18.

If necessary, a second end plate (not shown) can be used with corresponding elliptical grooves machined in the plate to provide support for the free end of the elliptical sections extending from base plate 104 to insure greater dimensional conformity for the elliptical segments.

It should be noted that the apparatus can be built relatively inexpensively, since there is a minimum of assembly, alignment and fastening required. All that is necessary is for the grooves to be machined into the end block which can be done by any convenient method, even, for example, by means of a standard pantograph type of device. If two end blocks are used,

. they can be fastened together by means of any convenient spacing members or they can be fastened to an intermediate housing.

It should also be noted that the materials are extremely cheap, easily replaceable and the entire system can be assembled and maintained with a minimum of precision work.

The embodiments of the illuminating systems discussed have included elliptical reflecting elements formed from two families of ellipses, with elements from each of the families being placed in alternating quadrants about the light source-However, it should be pointed out that the invention is in no means limited in the number of separate elliptical families which can be used, nor is the invention limited in the angular position or arc about the light source which the elements from each elliptical family can occupy.

. It will be understood that various changes in the details, materials and arrangements of parts which have been herein described and illustrated in order to explain the nature of the invention may be made by those 5 skilled in the art within the principle and scope of the invention as expressed in the appended claims.

What is claimed is:

1. Apparatus for directing with one or fewer reflections light from a light source to a portion of ,an object plane disposed remotely from said source comprising:

a plurality of elliptical reflectingsegments disposed between said source and said object plane, said segments being portions of a first series of concentric elliptical curves having one focus at said light source and a second focus on said object plane, and second plurality of elliptical reflecting segments disposed on the opposite side of said light source from said object plane, said second plurality of segments being portions of a second series of concentric elliptical curves having one focus at said light source and a second focus on said object plane spaced from said second focus of said first series of elliptical curves, said first and second plurality of elliptical reflecting segments being disposed so that light reflected by said second plurality of elliptical segments from said source passes between adjacent segments of said first plurality of elliptical reflecting segments to said second focus of said second plurality of elliptical reflecting segments.

2. The apparatus of claim 1 wherein said second focus of said first plurality of elliptical reflecting seg ments lies on the opposite side of a plane containing said light source and intersecting said object plane orthogonally from said first plurality of elliptical reflecting segments and wherein said second focus of said second plurality of elliptical reflecting segments lies on the same side of said plane containing said light source and intersecting said object plant orthogonally as said second plurality of elliptical reflecting segments.

3. The apparatusof claim 1 further including third and fourth pluralities of elliptical reflecting segments, said third and fourth pluralities of elliptical reflecting segments being portions of third and fourth series of concentric elliptical curves having one focus at said light source and second foci spaced from one another on said object plane.

4. The apparatus of claim .3 wherein said first, second, third and fourth pluralities of elliptical reflecting segments are arranged in first, second, third and fourth successive quadrants about said light source respectively.

5. The apparatus of claim 4 characterized in that said second foci of said first and third series of elliptical curves are coincident and said second foci of said second and fourth series of elliptical curves are coincident.

6. The apparatus of claim 4 wherein the elliptical reflecting segments of the two pluralities of elliptical reflecting segments closer to said object plane are disposed so that light rays reflected by them from said source cross each other before striking said object plane.

7. The apparatus of claim 1 said first and second plurality of elliptical reflecting segments each include:

an end block;

10. Apparatus for reflecting, with one or fewer reflections, light from a source to an area of an object plane disposed remotely from said source comprising:

-a first plurality of elliptical reflecting segments, said segments being portions of a plurality of concentric elliptical curves one focus at said light source and a second focus on said object plane; and

a second plurality of elliptical reflecting segments,

said second plurality of segments being portions of a second set of concentric elliptical curves having one focus at said light source and a second focus on said object plane, the focus on said object plane of said first series of elliptical curves being spaced from the focus on said object plane of said second series of elliptical curves; and

the elliptical segments of said first and second pluralities being disposed in alternate quadrant arcs about said light source.

I! i i

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1679108 *Nov 3, 1925Jul 31, 1928American Woodlite CorpCondensing reflector
US1757527 *Nov 13, 1926May 6, 1930Messrs Louis Poulsen & CompanyReflector for incandescent lamps
US2297124 *Mar 29, 1940Sep 29, 1942Rambusch Decorating CompanyLighting fixture
US2673288 *Oct 12, 1949Mar 23, 1954Westinghouse Brake & SignalReflector for the production of light beams
US3112893 *Aug 11, 1961Dec 3, 1963Corning Glass WorksReflector
US3283142 *Jul 1, 1963Nov 1, 1966Miller L FreemanLight reflectors
US3449561 *Jul 3, 1967Jun 10, 1969Textron Electronics IncAconic collector
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FR703009A * Title not available
GB265177A * Title not available
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4190355 *May 3, 1978Feb 26, 1980Xerox CorporationFacetted reflector
US4351019 *Jun 29, 1981Sep 21, 1982Xerox CorporationFacetted reflector
US4367946 *Jan 29, 1981Jan 11, 1983Eastman Kodak CompanyLight valve imaging apparatus having improved optical configuration
US7178947 *Jun 4, 2004Feb 20, 2007Dale MarksLighting device with elliptical fresnel mirror
Classifications
U.S. Classification362/291, 362/16, 362/346, 355/67
International ClassificationG03B27/02, G03B27/54, G03B27/16
Cooperative ClassificationG03B27/54, G03B27/16
European ClassificationG03B27/54, G03B27/16