CA1321988C - Light fixture - Google Patents
Light fixtureInfo
- Publication number
- CA1321988C CA1321988C CA000612081A CA612081A CA1321988C CA 1321988 C CA1321988 C CA 1321988C CA 000612081 A CA000612081 A CA 000612081A CA 612081 A CA612081 A CA 612081A CA 1321988 C CA1321988 C CA 1321988C
- Authority
- CA
- Canada
- Prior art keywords
- light
- prisms
- light fixture
- collimation
- axis
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21V7/00—Reflectors for light sources
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
- F21Y2103/00—Elongate light sources, e.g. fluorescent tubes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
- F21Y2115/00—Light-generating elements of semiconductor light sources
- F21Y2115/10—Light-emitting diodes [LED]
Abstract
Abstract LIGHT FIXTURE
A light fixture has a source of partially collimated light for emitting light having an axis of collimation. A structured surface has a plurality of prisms that are rendered reflective for reflecting light from the light source out of the cavity. The peaks of the prisms define a surface at least a portion of which makes an acute angle with the axis of collimation.
A light fixture has a source of partially collimated light for emitting light having an axis of collimation. A structured surface has a plurality of prisms that are rendered reflective for reflecting light from the light source out of the cavity. The peaks of the prisms define a surface at least a portion of which makes an acute angle with the axis of collimation.
Description
132~
The present invention relates to thin light fixtures.
In various situations thin light fixtures are desirable.
For example, back-lit flat panel displays normally should he kept as thin as possible. When they are thinner they tend to be llghter in weight and more compact, both desirable properties when they are used in applications such as portable computers.
Automobile taillights and brake lights also should be kept compact where possible. This is because space used by such lights comes at the expense of luggage space in the vehicle's trunk.
Various designs for thin panel lighting have been proposed. For example, our United States Patent 4,789,921 describes a Fresnel-type reflector lying on a conic surface.
Typically the Fresnel-type structures of that refle~tor are designed to mimic the performance of a parabolic reflector. The conic Fresnel provides a hlghly efficient compact light source, but suffers from the same disadvantage as other parabolic reflectors. That disadvantage is a lack of uniformity in intensity of light output. As may be expected, regions closer to the light source will be more brightly illuminated than those more distant from the light source.
Other designs have been proposed for use when uniform illuminatlon is desirable. One such proposal ls described ln our copendlng Canadian Patent Appll~ation Serial No. 562,153, filed March 23, 1988. That design utilizes a film known as rlght angle fllm. The use of right angle film in a light flxture allows the outpuk optical window to be very evenly llluminated, but requlres the separate construction of the right angle film and the ,.
;' ~ ~ f ~ . -"
: , . , ' .
'~' ' , '~ ' 1~21~88 insertion of that film into the light fixture. In some situations it would be desirable to construct a light fixture having a performance similar to that of the fixture using right angle film, without the requirement of the insertion of a separate film into the fixture.
Summary of the Invention According to the invention a housing defines an optical cavity having an optical window. A source of partially collimated light having an axis of collimation is located inside the optical cavity. A structured surface having a plurality of prisms thereon is positioned within the optical cavity such that the prisms reflect light through the optical window. The peaks of the prisms define a surface at least a portion of which makes an acute angle with the axis of collimation.
Brief Description of the Drawinq~
Flgure 1 is a view of a first embodiment of a light fixture according to the invention;
Eigure 2 is a view of a second embodiment of a light fixture according to the invention;
Figure 3 is a view of a third embodiment of a light fixture according to the invention; and Figure 4 is a view of a light fixture according to the lnvention having two light sources.
.
.
. ~ ,.
:
' ' - 132~ 9~8 Detailed Description Figure 1 illustrates a first embodiment of the invention. In the embodiment of Figure l a housing including walls 10 and 12 defines an optical cavity. The optical ~avity has an optical window with a light transmitting member 14, therein. Light transmitting member 14 may be of a transparent or translucent material. If desired, light transmitting member 14 could include structures such as pillow optics or Fresnel prisms.
A source of partially collimated light 16 is positioned inside the optical cavity and adjacent side 10 of the housing. Light source 16 may be any source of partially collimated light such as a fluorescent tube or other gas discharge lighting element with an appropriate reflector or an incandescent light with a reflector.
Alternatively light source 16 could include a plurality of light emitting diodes (LEDs).
Side 22 of wall 12 is a structured surface having a plurality of, preferably triangular, prisms, 24, thereon.
In a preferred embodiment, prisms 24 are linear prisms.
Prisms 24 are rendered specularly reflective, typically by aluminum vapor coating. It is only necessary that prisms 24 be specularly reflective on the side adjacent light source 16, but it is typically easier to vapor coat both sides. Such prisms reflect light from light source 16 in a predetermined direction. Typically the predetermined direction will be perpendicular to transparent or translucent material 14.
Light source 16 emits a beam of substantially collimated light having an axis of collimation 18. Line 20 is drawn parallel to collimation axis 18. As may be seen, the peaks of prisms 24 define a planar surface that makes an acute angle ~ with line 2~, and thus with collimation axis 18. As a result side 22 of wall 12 cuts through the beam of light emitted by light source 16. Because structured surface 22 so cuts through the beam of light ", ,: , 1321 ~
emitted by light source 16, the entire aperture of the optical window is illuminated.
The structure of the present invention may be advantageously formed directly on the rear wall of the light fixture. Such a structure could be formed by injection molding. Alternatively a separate film having the structured surface described above could be placed in the light fixture.
Figure 2 shows an alternative embodiment to that of Figure 1. In the embodiment of Figure 2 structured surface 22' is curved. Thus the surface defined by the peaks of prisms 24 is curved rather than planar. As a result, that surface is parallel or nearly parallel to the axis of collimation in the region closest to light source 16, but forms a variety of acute angles with it in regions more distant from light source 16. This has the effect of causing prisms more distant from light source 16 to intercept a greater portion of the beam than those closer to light source 16. ~ecause the light beam will naturally expand as it progresses to locations distant from the source, the curvature helps to maintain uniformity of illumination.
Figure 3 illustrates an alternative embodiment wherein a housing 30 including walls 32, 34, 36 and 38 defines an optical cavity having an optical window. ~
transparent or translucent cover 40 lies in the optical window. Light from two partially coIlimated light sources is directed from light sources 42 and 44 to structured surface 46. The peaks of the prisms of structured surface 46 may define a planar surface lying at an angle to the axis of collimation of the light sources, similar to the embodiment of Figure 1 or may define a curved surface cutting through the beams of light as in the embodiment of Figure 2.
Figure 4 illustrates another embodiment of the invention wherein light source 14' includes a light emitter 50 and a structured surface 52. Structured surface 52 acts : ' ~;. . ~ , -" ` ` 132 1 9~8 in a manner similar to structured surface 22 to take light from a compact source 50 and provide a linear beam. The embodiment of Figure 4 then acts similarly to the embodiment of Figure 1 with surface 52 acting as a light source for structured surface 54.
-: , , . :
.~
",
The present invention relates to thin light fixtures.
In various situations thin light fixtures are desirable.
For example, back-lit flat panel displays normally should he kept as thin as possible. When they are thinner they tend to be llghter in weight and more compact, both desirable properties when they are used in applications such as portable computers.
Automobile taillights and brake lights also should be kept compact where possible. This is because space used by such lights comes at the expense of luggage space in the vehicle's trunk.
Various designs for thin panel lighting have been proposed. For example, our United States Patent 4,789,921 describes a Fresnel-type reflector lying on a conic surface.
Typically the Fresnel-type structures of that refle~tor are designed to mimic the performance of a parabolic reflector. The conic Fresnel provides a hlghly efficient compact light source, but suffers from the same disadvantage as other parabolic reflectors. That disadvantage is a lack of uniformity in intensity of light output. As may be expected, regions closer to the light source will be more brightly illuminated than those more distant from the light source.
Other designs have been proposed for use when uniform illuminatlon is desirable. One such proposal ls described ln our copendlng Canadian Patent Appll~ation Serial No. 562,153, filed March 23, 1988. That design utilizes a film known as rlght angle fllm. The use of right angle film in a light flxture allows the outpuk optical window to be very evenly llluminated, but requlres the separate construction of the right angle film and the ,.
;' ~ ~ f ~ . -"
: , . , ' .
'~' ' , '~ ' 1~21~88 insertion of that film into the light fixture. In some situations it would be desirable to construct a light fixture having a performance similar to that of the fixture using right angle film, without the requirement of the insertion of a separate film into the fixture.
Summary of the Invention According to the invention a housing defines an optical cavity having an optical window. A source of partially collimated light having an axis of collimation is located inside the optical cavity. A structured surface having a plurality of prisms thereon is positioned within the optical cavity such that the prisms reflect light through the optical window. The peaks of the prisms define a surface at least a portion of which makes an acute angle with the axis of collimation.
Brief Description of the Drawinq~
Flgure 1 is a view of a first embodiment of a light fixture according to the invention;
Eigure 2 is a view of a second embodiment of a light fixture according to the invention;
Figure 3 is a view of a third embodiment of a light fixture according to the invention; and Figure 4 is a view of a light fixture according to the lnvention having two light sources.
.
.
. ~ ,.
:
' ' - 132~ 9~8 Detailed Description Figure 1 illustrates a first embodiment of the invention. In the embodiment of Figure l a housing including walls 10 and 12 defines an optical cavity. The optical ~avity has an optical window with a light transmitting member 14, therein. Light transmitting member 14 may be of a transparent or translucent material. If desired, light transmitting member 14 could include structures such as pillow optics or Fresnel prisms.
A source of partially collimated light 16 is positioned inside the optical cavity and adjacent side 10 of the housing. Light source 16 may be any source of partially collimated light such as a fluorescent tube or other gas discharge lighting element with an appropriate reflector or an incandescent light with a reflector.
Alternatively light source 16 could include a plurality of light emitting diodes (LEDs).
Side 22 of wall 12 is a structured surface having a plurality of, preferably triangular, prisms, 24, thereon.
In a preferred embodiment, prisms 24 are linear prisms.
Prisms 24 are rendered specularly reflective, typically by aluminum vapor coating. It is only necessary that prisms 24 be specularly reflective on the side adjacent light source 16, but it is typically easier to vapor coat both sides. Such prisms reflect light from light source 16 in a predetermined direction. Typically the predetermined direction will be perpendicular to transparent or translucent material 14.
Light source 16 emits a beam of substantially collimated light having an axis of collimation 18. Line 20 is drawn parallel to collimation axis 18. As may be seen, the peaks of prisms 24 define a planar surface that makes an acute angle ~ with line 2~, and thus with collimation axis 18. As a result side 22 of wall 12 cuts through the beam of light emitted by light source 16. Because structured surface 22 so cuts through the beam of light ", ,: , 1321 ~
emitted by light source 16, the entire aperture of the optical window is illuminated.
The structure of the present invention may be advantageously formed directly on the rear wall of the light fixture. Such a structure could be formed by injection molding. Alternatively a separate film having the structured surface described above could be placed in the light fixture.
Figure 2 shows an alternative embodiment to that of Figure 1. In the embodiment of Figure 2 structured surface 22' is curved. Thus the surface defined by the peaks of prisms 24 is curved rather than planar. As a result, that surface is parallel or nearly parallel to the axis of collimation in the region closest to light source 16, but forms a variety of acute angles with it in regions more distant from light source 16. This has the effect of causing prisms more distant from light source 16 to intercept a greater portion of the beam than those closer to light source 16. ~ecause the light beam will naturally expand as it progresses to locations distant from the source, the curvature helps to maintain uniformity of illumination.
Figure 3 illustrates an alternative embodiment wherein a housing 30 including walls 32, 34, 36 and 38 defines an optical cavity having an optical window. ~
transparent or translucent cover 40 lies in the optical window. Light from two partially coIlimated light sources is directed from light sources 42 and 44 to structured surface 46. The peaks of the prisms of structured surface 46 may define a planar surface lying at an angle to the axis of collimation of the light sources, similar to the embodiment of Figure 1 or may define a curved surface cutting through the beams of light as in the embodiment of Figure 2.
Figure 4 illustrates another embodiment of the invention wherein light source 14' includes a light emitter 50 and a structured surface 52. Structured surface 52 acts : ' ~;. . ~ , -" ` ` 132 1 9~8 in a manner similar to structured surface 22 to take light from a compact source 50 and provide a linear beam. The embodiment of Figure 4 then acts similarly to the embodiment of Figure 1 with surface 52 acting as a light source for structured surface 54.
-: , , . :
.~
",
Claims (6)
1. A light fixture comprising:
a housing defining an optical cavity having an optical window, said housing having a inner surface on a side opposite said optical window;
light emitting means in said housing for emitting a partially collimated beam of light having an axis of collimation;
a plurality of prisms on said inner surface, each of said prisms having a specularly reflective surface on a side adjacent said light emitting means for reflecting light from said light emitting means out of said optical cavity through said optical window, the peaks of said prisms defining a surface, at least a portion of said surface forming an acute angle with said axis of collimation.
a housing defining an optical cavity having an optical window, said housing having a inner surface on a side opposite said optical window;
light emitting means in said housing for emitting a partially collimated beam of light having an axis of collimation;
a plurality of prisms on said inner surface, each of said prisms having a specularly reflective surface on a side adjacent said light emitting means for reflecting light from said light emitting means out of said optical cavity through said optical window, the peaks of said prisms defining a surface, at least a portion of said surface forming an acute angle with said axis of collimation.
2. The light fixture of Claim 1 wherein said surface defined by said peaks is smoothly curving.
3. The light fixture of Claim 1 further comprising a light transmitting member in said optical window.
4. The light fixture of Claim 3 wherein said prisms reflect light from said light emitting means in a direction substantially perpendicular to said light transmitting member.
5. The light fixture of Claim 4 wherein each of said specularly reflective surfaces makes an angle substantially equal to forty-five degrees with said axis of collimation.
6. The light fixture of Claim 1 wherein said prisms are linear prisms.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US25578488A | 1988-10-11 | 1988-10-11 | |
| US255,784 | 1988-10-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1321988C true CA1321988C (en) | 1993-09-07 |
Family
ID=22969851
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000612081A Expired - Fee Related CA1321988C (en) | 1988-10-11 | 1989-09-20 | Light fixture |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0364228A3 (en) |
| JP (1) | JPH02176692A (en) |
| AU (1) | AU633845B2 (en) |
| CA (1) | CA1321988C (en) |
| MX (1) | MX173264B (en) |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5365412A (en) * | 1993-01-07 | 1994-11-15 | Ford Motor Company | Low profile illuminator |
| US5434754A (en) * | 1993-12-27 | 1995-07-18 | Ford Motor Company | Light manifold |
| IT1281366B1 (en) * | 1995-09-27 | 1998-02-18 | Carello Spa | LIGHTING DEVICE POSSIBLE WITH REDUCED THICKNESS, IN PARTICULAR HEADLAMP OR HEADLIGHT FOR VEHICLES |
| JP3574365B2 (en) | 1999-05-28 | 2004-10-06 | ユニベルシテ・ド・リエージュ | Illumination device, its use and manufacturing method |
| JP2001345008A (en) * | 2000-05-31 | 2001-12-14 | Nippon Leiz Co Ltd | Surface light source device |
| DE10064703B4 (en) * | 2000-12-22 | 2012-04-12 | Koninklijke Philips Electronics N.V. | Sandwich-type plate element |
| JP3803062B2 (en) * | 2001-12-27 | 2006-08-02 | 矢崎総業株式会社 | Vehicle indicating device |
| US7473019B2 (en) * | 2005-09-29 | 2009-01-06 | Osram Opto Semiconductors Gmbh | Lighting apparatus |
| NL1030161C2 (en) | 2005-10-11 | 2007-04-12 | Matthijs Dirk Meulenbelt | Presentation device. |
| WO2008050783A1 (en) * | 2006-10-19 | 2008-05-02 | Panasonic Corporation | Light-emitting device and display unit and lighting unit using the same |
| JP2012501001A (en) * | 2008-08-26 | 2012-01-12 | 潘定国 | Directional circular reflector with equilateral triangular prism and disk-shaped light having the same |
| CN102859272B (en) * | 2010-04-30 | 2014-01-08 | 潘定国 | Light guide plate with micro prisms, manufacture methode thereof and plate-shape lamp and plate-shape lamp fixture made thereby |
| JP4865082B1 (en) * | 2010-11-16 | 2012-02-01 | 株式会社東芝 | Liquid crystal display device and backlight module |
| DE102012012649A1 (en) * | 2012-06-26 | 2014-01-16 | Bartenbach Holding Gmbh | lighting device |
| DE102012012621A1 (en) * | 2012-06-26 | 2014-01-02 | Bartenbach Holding Gmbh | lighting device |
| WO2014155281A1 (en) * | 2013-03-26 | 2014-10-02 | Koninklijke Philips N.V. | Lighting device and luminaire |
| DE102016117685A1 (en) * | 2016-09-20 | 2018-03-22 | HELLA GmbH & Co. KGaA | Lighting device for vehicles |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1580461A (en) * | 1968-07-11 | 1969-09-05 | ||
| JPS57174803A (en) * | 1981-04-20 | 1982-10-27 | Masayasu Negishi | Surface light source device |
| DE3605000A1 (en) * | 1985-02-22 | 1986-09-04 | Sharp Kk | LIGHTING DEVICE |
| US4799137A (en) * | 1987-03-24 | 1989-01-17 | Minnesota Mining And Manufacturing Company | Reflective film |
-
1989
- 1989-09-20 CA CA000612081A patent/CA1321988C/en not_active Expired - Fee Related
- 1989-09-20 AU AU41588/89A patent/AU633845B2/en not_active Ceased
- 1989-10-02 MX MX017791A patent/MX173264B/en unknown
- 1989-10-09 JP JP1263779A patent/JPH02176692A/en active Pending
- 1989-10-11 EP EP89310375A patent/EP0364228A3/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02176692A (en) | 1990-07-09 |
| MX173264B (en) | 1994-02-14 |
| AU4158889A (en) | 1990-04-26 |
| AU633845B2 (en) | 1993-02-11 |
| EP0364228A3 (en) | 1990-07-18 |
| EP0364228A2 (en) | 1990-04-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |