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Publication numberUS3609340 A
Publication typeGrant
Publication dateSep 28, 1971
Filing dateApr 17, 1969
Priority dateApr 23, 1968
Also published asDE1919199A1, DE1919199B2
Publication numberUS 3609340 A, US 3609340A, US-A-3609340, US3609340 A, US3609340A
InventorsHabro Lars Bertil
Original AssigneeVagbellysning Ab
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Improvements in lighting units
US 3609340 A
Abstract  available in
Images(1)
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Claims  available in
Description  (OCR text may contain errors)

United States Patent [7 2] Inventor Lars Bertil Habro Lidingo, Sweden [21] Appl. No. 816,963

[22] Filed Apr. 17, 1969 [45] Patented Sept. 28, 1971 [73] Assignee AB Vagbellysning Stockholm, Sweden [32] Priority Apr. 23, 1968 [33] Sweden [54] IMPROVEMENTS IN LIGHTING UNITS 3 Claims, 1 Drawing Fig.

[52] US. Cl. 240/41.1, 240/25, 240/4135 C [51] Int. Cl F2lm 3/04 [50] Field of Search 240/4l.l

[56] References Cited UNITED STATES PATENTS 2,647,203 7/ 1953 Smith 240/4l.l

Primary Examiner-Samuel S. Matthews Assistant Examiner-Richard L. Moses Attorney-Waters, Roditi, Schwartz & Nissen ABSTRACT: A lighting unit consists of an elliptic rotational reflector having the light source positioned in one focal point, and a convex reflector facing the elliptic rotational reflector and serving for polydirectionally radiating the light rays which are emitted by the light source and pass through the other focal point of the elliptic rotational reflector. The convex reflector has at least one cup-shaped inwardly bulging recess which reflects the light rays impinging thereon at least essentially parallel.

IMPROVEMENTS IN LIGHTING UNITS This invention relates to a lighting unit of the type comprising an elliptic rotational reflector having the light source positioned in one focal point thereof, and a convex reflector facing the elliptic rotational reflector and preferably formed as a segment of a sphere for polydirectionally radiating the light rays which are emitted by the light source and pass through the other focal point of the elliptic rotational reflector. The characteristic feature of the lighting unit resides in that the convex reflector hm at least one cup-shaped inwardly bulging recess which reflects the light rays impinging thereon at least essentially parallel.

When devoid of a cup-shaped inwardly bulging recess, the lighting unit presents the same character of radiation in all directions. A lighting unit having in accordance with the invention a cup-shaped inwardly bulging recess provides a certain directional effect on the light, and this effect can be exploited for illumination of a roadway laterally of the lighting unit.

The invention will now be more fully described in the following, reference being made to the accompanying drawing which in cross section illustrates the reflectors of the lighting unit in a preferred embodiment thereof.

1 designates an elliptic rotational reflector having the light source positioned in one focal point Fl thereof. The reflector 1 shall be of such a size as to entirely conceal the light source. Mounted above the reflector l is a convex reflector 2 with the reflecting surface facing downwardly. More precisely, the reflector 2 is formed as a segment of a sphere.

The light rays emitted by the light source are reflected by the reflector 1 through the other focal point F2 thereof towards the reflector 2 so that a polydirectional radiation is obtained within the area A-B.

The lighting unit presents rotation symmetry around a vertical axis drawn through the focal points F1 and F2, the lighting unit being carried by a post, mast or like element so as to be adapted for use as a stationary lamp, as for example, a stationary roadside lamp for illuminating a highway. A clear cover of glass or plastics shall preferably be arranged between the outer peripheries of the two reflectors 1 and 2.

In accordance with the invention, the reflector 2 has at least one cup-shaped inwardly bulging recess 3 which reflects the light rays impinging thereon at least essentially parallel, thereby providing a certain directional effect on the light.

As will appear from the drawing, the focal point P2 of the ellipse is the focus of a curve y=f(x), for instance, a parabola. When caused to rotate about the O-X-axis, this curve will generate the inwardly bulging recess 3 in the reflector 2. The light rays impinging on this section of the reflector 2 will thus emerge from the lighting unit in parallel relationship. The size of the recess 3 is determined by the amount of light to be reflected by the recess. Normally, the recess 3 is given the size shown in the drawing so as to extend from the reflector center to the periphery of the reflector 2, thereby forming an annular recess reflecting a peripheral array of essentially parallel light rays.

The angle a by which the O-X-axis is inclined in relation to the horizontal plane H is determinative of the direction in which the light emerges from the cup-shaped inwardly bulging recess 3. By changing the angle a it is thus possible to attain the desired angle of radiation of the lighting unit.

When it is desired to throw the light along a roadway in both directions as measured from the lighting unit, the reflector 2 is provided with two cup-shaped inwardly bulging recesses 3 of the above-mentioned design rather than a single annular recess 3. When the lighting unit is to be placed laterally adjacent to the roadway to be illuminated, the light should be directed slightly obliquely forwardly to cover the roadway. This is attained by causing the longitudinal axes of the two recesses 3 to be axially offset relative to each other so as to be displaced at an angle of more or less than with one another. The same effect can be attained by asymmetrically inclining the reflector 2 from a horizontal plane so that the reflector edge closest to the edge of the roadway is at a greater hei ht over the ground.

e reflector 2 may very well have more than two cupshaped inwardly bulging recesses 3. For instance, with four cup-shaped inwardly bulging recesses 3 uniformly distributed over the circumference, an approximately square lighted area will be obtained on the ground.

The invention is not limited to the embodiment described above and shown in the drawing but can be modified within the scope of the appended claims.

What I claim and desire to secure by Letters Patent is:

l. A lighting unit of the type comprising an elliptic rotational reflector having a light source positioned in one focal point thereof; and a convex reflector facing the elliptic rotational reflector and preferably fonned as a segment of a sphere for polydirectionally radiating the light rays which are emitted by the light source and which pass through the other focal point of the elliptic rotational reflector, said convex reflector having at least one cup-shaped inwardly bulging recess which reflects the light rays impinging thereon at least essentially parallel, said cup-shaped inwardly bulging recess being defined by a generated curve yflx) the focus of which is situated in the other focal point (F2) of the elliptic rotational reflector, said curve having been caused to rotate about its axis (O-X) through the focus.

2. A lighting unit as claimed in claim 1, wherein the convex reflector has two substantially diametrically opposed, cupshaped, inwardly bulging recesses.

3. A lighting unit is claimed in claim 1, wherein the axis (O-X) of the curve y=f(x) through the focus is inclined in relation to the horizontal plane.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3983039 *Mar 3, 1975Sep 28, 1976Fusion Systems CorporationNon-symmetrical reflector for ultraviolet curing
US4075471 *Oct 8, 1975Feb 21, 1978Lucas Electrical Company LimitedLamp assembly
US4112483 *Dec 5, 1977Sep 5, 1978Optical Coating Laboratory, Inc.Lighting fixture and method using multiple reflections
US4174533 *Oct 3, 1977Nov 13, 1979Compagnie Des Lampes, Societe AnonymeWaveflux concentration reflector
US4194234 *Sep 6, 1978Mar 18, 1980Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen MbhSimultaneous multi directional single source multiple reflector electronic photo flash unit
US4298909 *Jun 13, 1979Nov 3, 1981Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen MbhPhotoflash reflector configuration
US4310876 *Mar 17, 1980Jan 12, 1982Small Jr Edward ALighting fixture and method using multiple reflections
US4583528 *Nov 8, 1984Apr 22, 1986Jack BaumanExamining device with improved optical coupling between the light source and light conductor
US4669449 *Feb 18, 1986Jun 2, 1987Jack BaumanSubmergible laryngoscope metallic housing for fiber optics power source
US4679547 *Feb 19, 1986Jul 14, 1987Jack BaumanFluid submersible laryngoscope
US4694822 *Apr 1, 1986Sep 22, 1987Jack BaumanSubmergible laryngoscope battery housing
US4709312 *Jun 24, 1986Nov 24, 1987Ruud Lighting, Inc.Floodlight with improved reflector system
US4729367 *Jan 27, 1987Mar 8, 1988Jack BaumanSubmergible laryngoscope with handle fluid sealing means
US4809147 *Apr 25, 1988Feb 28, 1989Masataka NegishiLighting device
US4974138 *Nov 18, 1988Nov 27, 1990Masataka NegishiLighting device
US5199782 *Jan 21, 1992Apr 6, 1993Glen Co. Breda & Associates, Inc.Illumination system for vanity or the like
US5501651 *Jun 13, 1994Mar 26, 1996Bauman; JackFluid submersible laryngoscope preventing electrolytic current flow
US5873646 *Mar 20, 1997Feb 23, 1999Aktiebolaget ElectroluxLighting arrangement at a refrigerator or freezer cabinet
US6431737 *Mar 24, 2000Aug 13, 2002Stanley Electric Co., Ltd.Vehicle headlamp having multi-reflex optical system
US6439745Jan 12, 2001Aug 27, 2002Stanley Electric Co., Ltd.Light composition for vehicle light
US8506128 *May 27, 2010Aug 13, 2013Seiko Epson CorporationLight source device, illumination system, and projector
US20100302510 *Dec 2, 2010Seiko Epson CorporationLight source device, illumination system, and projector
EP2295852A2 *Aug 27, 2010Mar 16, 2011Münz, ChristophReflector arrangement
Classifications
U.S. Classification362/303, 362/347, 362/346
International ClassificationF21V7/00, F21V7/04, F21V7/09
Cooperative ClassificationF21V7/0008, F21V7/09
European ClassificationF21V7/09, F21V7/00A