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Publication numberUS1259493 A
Publication typeGrant
Publication dateMar 19, 1918
Filing dateAug 7, 1917
Priority dateAug 7, 1917
Publication numberUS 1259493 A, US 1259493A, US-A-1259493, US1259493 A, US1259493A
InventorsWilliam A Dorey
Original AssigneeHolophane Glass Company Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Illuminating appliance.
US 1259493 A
Abstract  available in
Images(2)
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Claims  available in
Description  (OCR text may contain errors)

W. A. DOREY.

ILLUMINATING APPLIANCE.

APPLICATION FILED AUGJ. 1917.

l w iw, Emma Mar. 19, 1918 2 SHEETS-SHEET 2.

A TTOR/V E Y w. A. DOREY.

ILLUMINATING APPLIANCE.

APPLICATION FILED AUGJ. I9I7.

1,259,498. Patented Mar. 19, 1918.

2 SHEETS-SHEET l.

H/d/MW, dw aw A TTOfl/VEV WILLIAM A. DOEEY, 0F NEWARK, OHIO, ASSIG-NOB T0 HOLOPHANE GLASS COMPANY, me, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

ILLUMINATING AIPPLIANCE.

Specification of Letters Batent.

Patented Mar. 19, 191%..

To all whom it may concern:

Be it known that 1, WILLIAM A. Donny, a citizen of the United States, residing at Newark, in the county of Licking, State of Ohio, have invented certain new and useful Improvements in Illuminating Appliances, of which the following is a specification.

The object of my invention is to construct an illuminating appliance which shall produce eflicient illumination on the working plane and at the same time reduce the glare to a minimum. It is accomplished by reducing the amount of light emitted in certain zones, and preventing undiflused light from being emitted in said zones. Eficient combinations of this sort are formed in the known forms of open mouth prismatic reflector, but a portion of the light striking the surface of such a reflector is transmitted giving the appearance of a bright spot on the outside of the reflector, which is in line with the light source, and the eye of the observer. Under certain conditions where the reflector is close to the observer or mounted low, this bright spot may become troublesome. In the present invention, the reflector portion stops at such an angle that such bright spots are not visible at any ordinary point of view. At this point, the transmitting part of the appliance begins and extends to an angle equivalent to that of the ordinary form of rismatic reflector. With the concentrated light sources, now in use, the refracting construction used on this transmitting portion can be made so as to permit little or no undiflused light to lee-emitted at troublesome angles.

Figure 1 is an elevation of a shade-reflector made according to my invention, with a portion cut away to show the vertical section. Figs. 2 and 3 are vertical sections of further modifications of my invention.

The device is compound; one portion, generally'the upper being formed as a reflector, and the lower portion as a transmitting shade. The device is shown of crystal glass, but tinted, colored, acid etched, or sand blasted glass can be used; or the reflector portion may be made of opaque material.

In the preferred form, the reflector is formed of crystal glass which has on its outer surface radial double reflecting prisms adapted to reflect li ht rays from the source within, through an out of the open mouth of the appliance. Between the reflector and the refracting portion is a band-like portion joining the reflector to the refractor. The only mechanical reason for using this is to secure good manufacturing conditions. The refractor portion consists of a band of refracting prisms, the lower portion of this band being of smaller diameter than the upper fpart thereof. In fact, the opening of the re 'racting portion need only be of such width as to permit the removal of the lamp.

The reflector is designed so that practically no light rays from the source are reflected from it to the inner surface of the transmitting shade portion, as such light would be more scattered than light rays directly incident on the shade portion, and would not pass out in such angles as to pro duce the desired definite cutofli' or diminution above the angle of maximum light intensity. The contour of the upper reflector is substantiallv elliptical, that is, of such outline that if the light source is placed in one focus the reflected rays will tend to pass through the other focus. In actual design, in order to get difference in distribution, we are only limited to the requirements of getting the reflected rays through the open mouth. As this is of somewhat restricted area, however, the reflector can always be considered as a combination of elliptical and parabolic constructions, if not as a simple ellipse.

The mouth of the transmittin portion is of such size that the reflected lig t from the reflector portion may be made to pass through it at such angles as to give desirable distribution without loss by impinging on the transmitting portion. The shape of the transmitting portion and its relation to the light source are such that the light rays striking it are refracted efliciently into the useful zones.

In the figures, B is the upper reflector portion having on its outer surface double reflecting prisms. The neck portion A in each case is of conventional form. G is the light source of which E is the center and taken as the light source for the purpose of showing the action of typical light rays.

This point E is taken as one focus of the various ellipses and as the focus of the pa rabola forming the contour of the upper reflector part. The lower refractin portion D of the appliance is shown as wel ed to the reflector by means of band C, which has reflecting prisms upon it. Portion D has an open mouth F large enough to permit passage of the lamp G, and has horizontal refracting prisms upon its outer, surface. The light rays incident from the light source on the reflector 13, above point 2, are for all practical purposes negligible.

In the modification shown in Fig. 1, the contour of the reflector from 2 to 5 and from 7 to 10 is elliptical, while that from 5 to 7 is parabolic. Rays from 2 to 5 pass through point 18, placed close enough to the edge of the mouth part to ermit a Wide distribution of the light an yet not close enough to cause the rays from the extreme edge of the sourceto be reflected on the inner surface of the transmitting portion. The ray point 5 coincides with the axis of the ellipse. Point 18 forms a secondary light focus for all rays incident on the elliptical portion 2 to 5 of the reflector. Rays incident on points from 7 to 10 pass through point 19. This point is so placed that practically all light reflected from extreme portions of the light source will miss the adjacent side of the transmitting portion. This point 19 forms the secondary focus of rays incident on the second elliptical portion of the reflector. Portion 5 to 7 on'the reflector is parabolic in contour and. all the rays from the source E reflected by it will be parallel to rays 4: and '8. The refracting transmitting part extends from about -90 degrees With the vertical axis to about '55 degrees with the vertical axis and is designed to emit through its open month all direct light from the source emitted at angles less than 55 degrees to 60 degrees. The refractor portion is here shown as concave and provided with horizontal refracting prisms which inthis case depress the major portion of the light striking the in her surface to about 45 degrees and permit very little light to pass out above an angle of 60 degrees. Typical light ray 16 from the light source is incident on such refracting prisms, and refracted and transmitted in direction 17 as shown. Light rays 12 incident on the connecting band at point 13 are reflected and transmitted in typical light rays 14 and15.

Fig. 2 is the vertical cross section of a modification in which the contour of the reflector from 20 to 21 andfrom 22 to 23 is elliptical, While that from 21 to 22 is parabolic. The light rays incident from the light source on the reflector B, above point 20, are for all practical purposes neg-v ligible. Rays from 20 to 21 pass through point 24, so placed that the reflected rays are at angles from perpendicular to 33 degrees with the perpendicular. Point 24 forms a secondary light focus for all rays incident on the elliptical portion 20 to 21 of the reflector. Rays incident on points from 22 to 23 pass through point 25. This point is so placed that practically all light reflected from extreme portions of the light source will pass out through the open mouth at angles less than degrees and very little of the light will strike the adjacent side of the transmitting portion. This point forms the secondary focus of rays incident on the second elliptical portion of the reflector. Portion 21 to 22 on the reflector is parabolic in contour and all the rays from the source E reflected by it will be parallel to rays 26 and 27.

The refracting transmitting part extends from. about 85 degrees With the vertical axis to about degrees With the vertical axis and is designed to emit through its open mouth all direct light from the sources emitted at angles less than 55 degrees to 60 degrees. The refractor portion is here shown as concave and provided with horizontal refracting prisms which in this case depress the major portion of the light striking the inner surface to about 33 degrees .and permit very little light to pass out above an angle of 60 degrees. Typical .light ray 28 from the light source is ncident on such refracting prisms, and refracted and transmitted in direction 29 as shown.

Light rays 30 incident on the connecting band at point 31 are refracted and transmitted in typical light rays 32 and 33.

In Fig. 3, a vertical cross section of a further modification of my invention is shown. In this modification the light rays incident from the light source on the reflector B, above point 34, are for all practical purposes negligible. Rays from 34 to 35 pass through point 37, placed at the edge of the mouth part. In this case rays from theextreme edge of the light source are reflected on the opposite side of the transmitting portion because the prisms at the lower edge are so shallow that they will not direct this light disadvantageously and a wide angle of maximum intensity is desired Without increase in' the size of the mouth F. Point 37 forms a secondary light focus for all rays incident on the elliptical portion 34 to 35 of the reflector. Portion 35 to 36 on the reflector is parabolic in contour and all the rays from the source E reflected by it will be parallel to rays 38 to 39.

The refracting transmitting part extends from about 85 degrees with the vertical axis to about 55 degrees with the vertical axis and is designed to emit through its open mouth all direct light from the sources emitted at angles less than 55 degrees to 60 degrees. The refractor portion is here shown as concave and provided With hori zontal refracting prisms which in this case depress the major portion of the light striking the inner surface to about 55 degrees and permit very little light to pass out above an angle of 60 degrees. Typical light ray 40 from the light source is incident on such refracting prisms, and refracted and transmitted in direction41 as shown. Light rays 42 incident on the connecting band at point 45 are refracted and transmitted in typical light rays 43 and 44.

Great variety of distribution is obtainable by this invention. Figs. 1, 2 and 3 show three distinct types in which variations are produced by dlflerent ellipsoidal combinations in the reflector together with difierence of curvature of the transmittin part. For instance, in Fig. 1 a broad distri ution is given inv which an area is lighted, the diameter of which is twice the distance of the light source above the plane lighted. The area of distribution of Fig. 2is smaller but more concentrated, being 14 times the distance of the light'source above the plane lighted. The broadest area of distribution is obtained by the modification shown in Fig. 3, in which the diameter of the area lighted is 2% times the distance of the light source above the plane lighted.

The appliance 1s shown in pendent position but it can be used upright or pendent; any light source can be used but accuracy of position is necessary to secure good results.

Having described my invention, what I claim is:

1. An illuminating appliance consisting of an upper reflector, a lower light transmitting shade, having an open mouth the reflector being substantially ellipsoidal in contour and adapted to throw the majority of light rays incident on its surface directly through and out of the open mouth and the shade transmitting and directing incident light rays at angles to roduce a relatively sudden diminution in light intensity above the angle of maximum light intensity.

2. An illuminating appliance consisting of a light transmitting shade having an open mouth and an upper reflector substantially ellipsoidal in contour and provided on its outer surface with radial reflecting prisms adapted to throw the majority of light rays incident on its surface directly through and out of the open mouth and the shade which has upon its surface prisms adapted to transmit and direct incident light rays at angles to produce a relatively sudden diminution in light intensity above the angle of maximum light intensity.

3. An illuminating appliance consisting of a light source and surroundin the same, a reflector and an open mouthed light transmitting shade, the reflector being uppermost and having its rim substantially on a line with a lower edge of the light source and being adapted to throw the majority of light rays incident on its surface directly throu h and out of the open mouth of the shade, which shade transmits and directs light rays incident thereon at angles to produce a relatively sudden diminution in light intensity above the angle of maximum light intensity.

4. An illuminating appliance consisting of a light source and surrounding the same, a glass reflector and anopen mouthed light transmitting shade, the reflector being uppermost and having its lower rim substantially On a line with the lower edge of the light source and being rovided with reflecting prisms adapted to t row the majority of light rays incident on its surface directly through and out of the open mouth of the shade, which shade transmits and directs light rays incident thereon at angles to produce a relatively sudden diminution in light intensity above the angle of maximum light intensity.

5. An illuminating appliance consisting of a light source and surroundin the same, an upper reflector, and a lower ight transmitting open mouthed shade, the reflector being substantially ellipsoidal in contour and having its lower rim substantially on a line with the lower edge of the light source and being provided on its outer surface with radial reflecting prisms adapted to throw the majority of light rays incident on its surface directly through and out of the open WILLIAM A. DOREY.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2818500 *Jul 3, 1953Dec 31, 1957Holophane Co IncPrismatic reflectors
US3062953 *May 5, 1959Nov 6, 1962Mc Graw Edison CoLuminaire and refractor therefor
US4903180 *Dec 7, 1988Feb 20, 1990General Electric CompanyLuminaire with protected prismatic reflector
US5036445 *Feb 20, 1990Jul 30, 1991General Electric CompanyMeans and method for controlling the uplighting properties of a luminaire having a reflector of substantially transparent material with a prismatic outer surface
US6027231 *Dec 24, 1997Feb 22, 2000Holophane CorporationLuminaire assembly
US6575601Mar 15, 2002Jun 10, 2003Lexalite International CorporationLighting fixture optical assembly including relector/refractor and shroud
US7866855Dec 2, 2005Jan 11, 2011ABL IP Holding LLC.Luminaire reflector having improved prism transition
EP1828674A2 *Dec 2, 2005Sep 5, 2007Acuity Brands, Inc.Luminaire reflector having improved prism transition
WO2006060642A2 *Dec 2, 2005Jun 8, 2006Yaser S AbdelsamedLuminaire reflector having improved prism transition
Classifications
U.S. Classification362/309, D26/26
Cooperative ClassificationF21V5/00