JPH052236B2 - - Google Patents
Info
- Publication number
- JPH052236B2 JPH052236B2 JP61220577A JP22057786A JPH052236B2 JP H052236 B2 JPH052236 B2 JP H052236B2 JP 61220577 A JP61220577 A JP 61220577A JP 22057786 A JP22057786 A JP 22057786A JP H052236 B2 JPH052236 B2 JP H052236B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- light source
- diffuser plate
- plate
- half mirror
- 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 - Lifetime
Links
- 238000005286 illumination Methods 0.000 claims description 6
- 230000007423 decrease Effects 0.000 description 7
- 238000009792 diffusion process Methods 0.000 description 5
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000002834 transmittance Methods 0.000 description 4
- 230000001678 irradiating effect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000011022 opal Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Landscapes
- Liquid Crystal (AREA)
- Devices For Indicating Variable Information By Combining Individual Elements (AREA)
Description
【発明の詳細な説明】
産業上の利用分野
本発明は透過形画像表示装置の背面に配置し、
画像表示素子の背面より均一に照明する照明装置
に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is arranged on the back side of a transmissive image display device,
The present invention relates to an illumination device that uniformly illuminates an image display element from the back side.
従来の技術
液晶などの画像表示素子を用いた透過形画像表
示装置には、その画像表示素子を背面から明るく
均一に照明するために、例えば第４図に示すよう
な照明装置が用いられている。BACKGROUND TECHNOLOGY Transmissive image display devices using image display elements such as liquid crystals use an illumination device as shown in FIG. 4, for example, in order to brightly and uniformly illuminate the image display elements from the back side. .
すなわち、線状の光源１の下部に、前記光源１
から照射される光を効率よく集光させるための断
面形状が放物線の樋形の反射板２を設け、光源１
からの直射光と反射板２からの反射光とを、光源
１の上部に設けた拡散板３に照射することによつ
て、前記拡散板３の上に平行に置かれた画像表示
素子４の背面を照明している。 That is, the light source 1 is placed below the linear light source 1.
A gutter-shaped reflector plate 2 with a parabolic cross section is provided to efficiently condense the light emitted from the light source 1.
By irradiating the diffuser plate 3 provided on the upper part of the light source 1 with the direct light from the source and the reflected light from the reflector plate 2, the image display element 4 placed parallel to the diffuser plate 3 is illuminated. The back is illuminated.
発明が解決しようとする問題点
このような従来の照明装置において、反射板２
の断面形状が放物線であることから、反射板２に
よつて反射した光源１からの光の一部は、拡散板
３に対してほぼ垂直に照射される。この反射板２
からの反射光のみが拡散板３に照射されるのであ
れば、拡散板３の輝度分布は均一に近い状態にな
る。しかし、拡散板３には前記反射光の他に光源
１からの直射光も照射されるため、その輝度分布
は第５図に示すように直射光と反射光が合成され
て、拡散板３の中央部すなわち光源１の近傍の輝
度が高く、拡散板３の端部すなわち光源から離れ
るにつれて輝度が低下するため、画像表示素子４
の明るさに不均一を生ずる。Problems to be Solved by the Invention In such a conventional lighting device, the reflector 2
Since the cross-sectional shape of is a parabola, a part of the light from the light source 1 reflected by the reflection plate 2 is irradiated onto the diffuser plate 3 almost perpendicularly. This reflector 2
If only the reflected light is irradiated onto the diffuser plate 3, the luminance distribution of the diffuser plate 3 will be nearly uniform. However, since the diffuser plate 3 is irradiated with direct light from the light source 1 in addition to the reflected light, the brightness distribution is such that the direct light and reflected light are combined as shown in FIG. The brightness is high at the center, that is, near the light source 1, and decreases as you move away from the ends of the diffuser plate 3, that is, the light source.
This causes uneven brightness.
拡散板３の輝度分布を均一にする方法として、
前記光源１からの直射光を遮光することや、拡散
板３を拡散特性の高い材質（できるだけ完全拡散
面に近似させたもの：たとえばオパールガラスな
ど）に変更することも考えられるが、いずれも光
源１の光の利用効率を低下させるため望ましくな
い。 As a method to make the brightness distribution of the diffuser plate 3 uniform,
It is conceivable to block the direct light from the light source 1 or to change the diffusion plate 3 to a material with high diffusion properties (one that approximates a perfect diffusion surface as much as possible: for example, opal glass), but in either case, the light source This is undesirable because it lowers the efficiency of using light in step 1.
そこで、本発明は光源の光の利用効率を低下さ
せることなく、拡散板の輝度分布を均一にするも
のである。 Therefore, the present invention makes the luminance distribution of the diffuser plate uniform without reducing the efficiency of using light from the light source.
問題点を解決するための手段
そして上記問題点を解決する本発明の技術的な
手段は、拡散板の輝度が低下する部分、すなわち
光源から離れた部分に、光源と拡散板との間に設
けたハーフミラーからの反射光を照射することに
より、拡散板の輝度分布を均一にしようとするも
のである。Means for Solving the Problems The technical means of the present invention for solving the above-mentioned problems is to provide a part between the light source and the diffuser plate in the part of the diffuser plate where the brightness decreases, that is, in the part away from the light source. By irradiating the diffuser with reflected light from a half mirror, the luminance distribution of the diffuser plate is made uniform.
作 用
この技術的手段による作用は次のようになる。
すなわち、光源と拡散板との間にハーフミラーを
設ける。そして前記光源から直接拡散板に照射す
る光の一部をこのハーフミラーに照射させる。こ
こでハーフミラーにより反射した光を、光源の下
部に設けた反射板（断面形状が放物線になつてい
る）に照射し、その反射光を拡散板の輝度が低下
する部分（光源から離れた部分）に照射する。ま
た、ハーフミラーを透過した光は、そのまま拡散
板の光源の近傍部分に照射する。そして、拡散板
の光源から離れた部分と光源の近傍部分とにそれ
ぞれ照射する光量が、均等になるようにハーフミ
ラーの反射率と透過率を設定することにより、拡
散板の輝度分布を均一にすることができるもので
ある。Effect The effect of this technical means is as follows.
That is, a half mirror is provided between the light source and the diffuser plate. A part of the light that is directly irradiated onto the diffuser plate from the light source is irradiated onto this half mirror. Here, the light reflected by the half mirror is irradiated onto a reflector plate (with a parabolic cross-section) installed at the bottom of the light source, and the reflected light is directed to the part of the diffuser plate where the brightness decreases (the part far from the light source). ). Further, the light transmitted through the half mirror directly irradiates the portion of the diffuser plate near the light source. By setting the reflectance and transmittance of the half mirror so that the amount of light irradiated to the part of the diffuser far from the light source and the part near the light source is equal, the brightness distribution of the diffuser is made uniform. It is something that can be done.
実施例
以下、本発明の実施例について、添付図面にも
とづいて説明する。Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings.
第１図において５は線状の光源（たとえば蛍光
ランプなど）で、この光源５の上部には、光源５
の管軸方向と平行に拡散板６が設けられている。
さらに拡散板６の上には拡散板６と平行に置かれ
た画像表示素子７があり、前記拡散板６と画像表
示素子７は、その間隔が数mmと近接して配置され
ている。 In FIG. 1, reference numeral 5 indicates a linear light source (for example, a fluorescent lamp, etc.).
A diffusion plate 6 is provided parallel to the tube axis direction.
Furthermore, there is an image display element 7 placed above the diffuser plate 6 in parallel with the diffuser plate 6, and the diffuser plate 6 and the image display element 7 are arranged close to each other with an interval of several mm.
一方、光源５の下部には、断面形状が放物線で
かつ全体の形状が樋形をした反射板８が設けられ
ており、この放物線の焦点の位置に光源５が配置
されている。前記反射板８の材質は鏡面性の高い
アルミニウム板であり、光源５からの光の一部は
反射板８により拡散板６の全域に対してほぼ垂直
に照射される。 On the other hand, a reflecting plate 8 having a parabolic cross-sectional shape and a gutter-like overall shape is provided below the light source 5, and the light source 5 is placed at the focal point of this parabola. The material of the reflector 8 is an aluminum plate with high specularity, and a portion of the light from the light source 5 is irradiated almost perpendicularly to the entire area of the diffuser plate 6 by the reflector 8.
また光源５と拡散板８との間には第２図に示す
ように、光源５の管軸方向と平行に２つの平面
（ハーフミラー）を開き角αに設定したハーフミ
ラー９が設けられている。光源５からの光の一部
は前記ハーフミラー９に照射され、ここで反射光
ａと透過光ｂとに分離される。そして反射光ａは
反射板８にいつたん戻され、反射板８から再び反
射光として拡散板６の端部、すなわち光源５から
離れて輝度が低下する部分に照射される。一方、
ハーフミラー９を透過した透過光ｂは拡散板６の
中央部分、すなわち光源の近傍部分に照射され
る。 Further, as shown in FIG. 2, a half mirror 9 is provided between the light source 5 and the diffuser plate 8, with two planes (half mirrors) parallel to the tube axis direction of the light source 5 set at an opening angle α. There is. A portion of the light from the light source 5 is irradiated onto the half mirror 9, where it is separated into reflected light a and transmitted light b. The reflected light a is then returned to the reflecting plate 8, and from the reflecting plate 8, it is again irradiated as reflected light to the end portion of the diffuser plate 6, that is, the portion where the luminance decreases as it moves away from the light source 5. on the other hand,
The transmitted light b that has passed through the half mirror 9 is irradiated onto the central portion of the diffuser plate 6, that is, the portion near the light source.
照明装置を上記のように構成したのち、ハーフ
ミラー９の開き角αを適切な設定し、かつハーフ
ミラー９からの反射光ａと透過光ｂとの光量比が
拡散板６において均等になるように、ハーフミラ
ー９の反射率と透過率を適切な値に設定する（た
とえば、ハーフミラーを金属蒸着して、この蒸着
膜の膜厚をコントロールする）。この場合は拡散
板６の端部の輝度が中央部分より低下することか
ら、反射光Ａを増加させ透過光ｂを減少させるよ
うに、ハーフミラー９の反射率と透過率を設定す
る。 After configuring the illumination device as described above, the aperture angle α of the half mirror 9 is set appropriately, and the light amount ratio of the reflected light a and the transmitted light b from the half mirror 9 is made equal on the diffuser plate 6. First, the reflectance and transmittance of the half mirror 9 are set to appropriate values (for example, the half mirror is deposited with metal and the thickness of the deposited film is controlled). In this case, since the brightness at the ends of the diffuser plate 6 is lower than that at the center, the reflectance and transmittance of the half mirror 9 are set so as to increase reflected light A and decrease transmitted light B.
以上のことから拡散板６には第１図に示すよう
に、光源５から照射される光のうち、直接照射さ
れる光［直射光ｃ］と、反射板８によつて反射す
る光［反射光ｄ］、および前記ハーフミラー９か
らの反射光ａと透過光ｂとを合成した光がバラン
スよく照射されることになり、拡散板６における
輝度分布は第３図のようになる。 As shown in FIG. The light d] and the combined light of the reflected light a and the transmitted light b from the half mirror 9 are irradiated in a well-balanced manner, and the luminance distribution on the diffuser plate 6 becomes as shown in FIG.
第３図において、イは光源５からの直射光によ
る輝度分布、ロは反射板８から反射光による輝度
分布、ハはハーフミラー９の反射光による輝度分
布、ニは同じくハーフミラー９の透過光ｂによる
輝度分布であり、イ，ロ，ハ，ニを合成すると目
標とする輝度分布ホが得られる。 In FIG. 3, A is the brightness distribution due to the direct light from the light source 5, B is the brightness distribution due to the reflected light from the reflection plate 8, C is the brightness distribution due to the reflected light from the half mirror 9, and D is the transmitted light from the half mirror 9. This is the brightness distribution according to b, and by combining A, B, C, and D, the target brightness distribution E can be obtained.
なお、前記反射板８には、鏡面性の高いアルミ
ニウム板を用いたが、アルミニウム板の代わりに
アクリル樹脂などにアルミニウムを蒸着した反射
板を用いても、同様の効果を奏する。 Although an aluminum plate with high specularity is used as the reflecting plate 8, a similar effect can be obtained by using a reflecting plate made of acrylic resin or the like with aluminum vapor-deposited instead of the aluminum plate.
また、本実施例において、光源５には直管形の
蛍光ランプを用いたが、冷陰極放電ランプ、セグ
メント形ハロゲン電球などの線状源源、さらには
タンングステンランプやLEDなどを複数個、線
状につないだものを用いてもよい。 In this embodiment, a straight tube fluorescent lamp is used as the light source 5, but a linear source such as a cold cathode discharge lamp or a segmented halogen bulb, or even a plurality of tungsten lamps or LEDs may be used. You may also use one connected in a shape.
発明の効果
本発明は、光源から直接拡散板に照射される光
の一部を、光源と拡散板との間に設けたハーフミ
ラーによつて反射光と透過光とに分離し、拡散板
の輝度が低下する部分、すなわち光源から離れた
部分に前記ハーフミラーからの反射光を、また拡
散板の中央部分、すなわち光源の近傍部分に前記
ハーフミラーからの透過光をそれぞれ照射し、両
者の光量比をハーフミラーの反射率と透過率のコ
ントロールによつて設定するため、従来の照明装
置で問題となつていた拡散板の両端部の輝度の低
下を防止でき、均一な輝度分布を実現できる。Effects of the Invention The present invention separates a part of the light directly irradiated from the light source onto the diffuser plate into reflected light and transmitted light by a half mirror provided between the light source and the diffuser plate. The part where the brightness decreases, that is, the part far from the light source, is irradiated with the reflected light from the half mirror, and the central part of the diffuser plate, that is, the part near the light source, is irradiated with the transmitted light from the half mirror. Since the ratio is set by controlling the reflectance and transmittance of the half mirror, it is possible to prevent a decrease in brightness at both ends of the diffuser plate, which was a problem with conventional lighting devices, and achieve a uniform brightness distribution.
また、光源から照射される光のうち、その直射
光と反射板からの反射光、さらにはハーフミラー
からの反射光と透過光をすべて拡散板に照射でき
るため、光源の光の利用効率がすぐれている。 In addition, of the light emitted from the light source, the direct light, the reflected light from the reflector, and the reflected light and transmitted light from the half mirror can all be irradiated onto the diffuser plate, which improves the efficiency of using the light from the light source. ing.
第１図は本発明の実施例である透過形画像表示
装置の照明装置の断面図、第２図は同照明装置に
おけるハーフミラーの斜視図、第３図は同照明装
置における拡散板の輝度分布特性図、第４図は従
来の照明装置の断面図、第５図は従来の照明装置
における拡散板の輝度分布特性図である。
５……光源、６……拡散板、７……画像表示素
子、８……反射板、９……ハーフミラー。
FIG. 1 is a sectional view of a lighting device of a transmissive image display device according to an embodiment of the present invention, FIG. 2 is a perspective view of a half mirror in the lighting device, and FIG. 3 is a luminance distribution of a diffuser plate in the lighting device. FIG. 4 is a sectional view of a conventional illumination device, and FIG. 5 is a characteristic diagram of the luminance distribution of a diffuser plate in the conventional illumination device. 5... Light source, 6... Diffusion plate, 7... Image display element, 8... Reflection plate, 9... Half mirror.
Claims (1)
光源からの光の一部を反射させ、この反射光を拡
散板に照射させる反射板と、前記光源と拡散板の
間に設けられて光源からの光の一部を反射させて
前記反射板に返すとともに、透過する光を拡散板
に照射させるハーフミラーと、前記ハーフミラー
の上部に設けられて、前記光源からの直射光の一
部および前記反射板からの反射光と、前記ハーフ
ミラーからの反射光と透過光とが照射される拡散
板とを備えた透過形画像表示装置の照明装置。1. A linear light source, a reflector plate provided below the light source to reflect a portion of the light from the light source and irradiate the reflected light to the diffuser plate, and a reflector plate provided between the light source and the diffuser plate to reflect a portion of the light from the light source. a half mirror that reflects a part of the light from the light source and returns it to the reflection plate, and irradiates the transmitted light to the diffuser plate; An illumination device for a transmissive image display device, comprising a diffuser plate that is irradiated with reflected light from a reflecting plate, and reflected light and transmitted light from the half mirror.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61220577A JPS6374087A (en) | 1986-09-17 | 1986-09-17 | Lighting apparatus for transmission type image display device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61220577A JPS6374087A (en) | 1986-09-17 | 1986-09-17 | Lighting apparatus for transmission type image display device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6374087A JPS6374087A (en) | 1988-04-04 |
| JPH052236B2 true JPH052236B2 (en) | 1993-01-12 |
Family
ID=16753160
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61220577A Granted JPS6374087A (en) | 1986-09-17 | 1986-09-17 | Lighting apparatus for transmission type image display device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6374087A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2515634Y2 (en) * | 1989-02-14 | 1996-10-30 | 株式会社ゼニライトブイ | Waterside target light |
| JP5486275B2 (en) * | 2009-11-25 | 2014-05-07 | パナソニック液晶ディスプレイ株式会社 | Liquid crystal display |
-
1986
- 1986-09-17 JP JP61220577A patent/JPS6374087A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6374087A (en) | 1988-04-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6280052B1 (en) | Light diffuser | |
| JP2511148B2 (en) | Liquid crystal device | |
| US7213949B2 (en) | Four segment reflector | |
| JPS5826405A (en) | Lighting apparatus with opal plate | |
| JPH052236B2 (en) | ||
| US4833575A (en) | Brightness equalizing light filter system | |
| JP3346094B2 (en) | Elevator ceiling lighting system | |
| JPH041350B2 (en) | ||
| JPH05281540A (en) | Lighting system and liquid crystal display device | |
| JPH052237B2 (en) | ||
| JP2874418B2 (en) | Lighting equipment | |
| JPH0515241B2 (en) | ||
| JPS6368815A (en) | Backlighting structure for liquid crystal display device | |
| JP2940241B2 (en) | Lighting equipment | |
| JPH0676614A (en) | Luminaire | |
| JPH0617154Y2 (en) | Liquid crystal display | |
| JPH052165A (en) | Lighting device | |
| JPH03126982A (en) | Display device | |
| JPH08293205A (en) | Light source device, and its lighting device, back light, and liquid-crystal display | |
| JPH0721962B2 (en) | lighting equipment | |
| JP2603885Y2 (en) | Lighting equipment | |
| JPH01253711A (en) | Lighting device for transmission type image display device | |
| JPH05150238A (en) | Illumination device and liquid crystal display device | |
| JPH02148606A (en) | Lighting apparatus | |
| JP2000123619A (en) | Illumination lamp unit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |