JPH055952A - Lighting device and projection type display device - Google Patents

Abstract

PURPOSE:To display an image with high brightness and high quality by constituting this projection type display device of a reflector having a shape obtained by rotating an elliptic curve in which a light source like a point and a major axis are inclined from an optical axis around the optical axis and setting up the reflector so that all light beams reflected by the reflector are made incident upon a face to be irradiated. CONSTITUTION:One of the cross sections of the reflector 12 is a curve on an ellipse 15 set up so that a point arranged in the vicinity of the light source on the optical axis 14 is the 1st focus 16 and an end point on the face 13 to be irradiated is the 2nd focus 17a. The other cross section is also a curve on an ellipse 15 constituted of the 1st focus 16 and the 2nd focus 17b to be the end point of the face 13 to be irradiated. Light flux reflected by a fine reflecting face contacting with a point (a) plots an image 18a of a discharge arc on the face 13, contacts with the frame of the face 13, plots the images 18b, 18c of discharge arcs reflected by a fine reflecting face contacting with points (b), (c), and then contacts with the frame of the face 13. Thereby all light beams reflected by the reflector 12 are made incident upon the inside of the face 13 to be irradiated and illuminance around the frame becomes the highest available illuminance.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、店舗照明等に用いる照
明装置と投射型表示装置の構成に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a configuration of a lighting device and a projection type display device used for shop lighting or the like.

【０００２】[0002]

【従来の技術】ライトバルブの映像を拡大表示する投射
型表示装置には、ほぼ平行な白色光束を出射する照明装
置を用いる。従来、この照明装置では、光源ランプの放
射光束を回転放物鏡により平行化するというものが一般
的である。この照明装置の構成を図２（Ａ）に示す。点
光源に近い光源ランプ２１から放射される光束は、光源
位置を焦点とする回転放物鏡２２により反射されて、ほ
ぼ平行な反射光束２３となる。この反射光束２３は集光
レンズ２４を経て液晶ライトバルブ２５で変調され投射
レンズ２６に効率よく入射する。2. Description of the Related Art A projection type display device for enlarging and displaying an image of a light valve uses an illuminating device for emitting a substantially parallel white light flux. Conventionally, in this illuminating device, it is general that the radiation flux of the light source lamp is collimated by a rotating parabolic mirror. The structure of this lighting device is shown in FIG. The light flux emitted from the light source lamp 21 close to the point light source is reflected by the rotating parabolic mirror 22 whose focal point is the light source position, and becomes a substantially parallel reflected light flux 23. The reflected light flux 23 is modulated by the liquid crystal light valve 25 via the condenser lens 24 and efficiently enters the projection lens 26.

【０００３】[0003]

【発明が解決しようとする課題】しかし前述の従来技術
では、ライトバルブ２５上の照度分布が図２（Ｂ）に示
すように、中心ほど高照度となり、従って、図２（Ａ）
のスクリーン２７上においても中心が明るく周辺が暗い
映像となり、不自然な感じになる。また、ライトバルブ
の端部照度と中心照度の比（以下、照度比と略す）を１
に近づけようとするとライトバルブから外れる光束が増
し、利用効率が低くなる。However, in the above-mentioned conventional technique, the illuminance distribution on the light valve 25 becomes higher toward the center, as shown in FIG.
An image with a bright center and a dark periphery is also displayed on the screen 27, which gives an unnatural feeling. Also, the ratio of the edge illuminance to the central illuminance of the light valve (hereinafter, abbreviated as illuminance ratio) is 1
If you try to get closer to, the luminous flux out of the light valve will increase and the utilization efficiency will decrease.

【０００４】そこで、本発明はこのような問題点を解決
するもので、その目的とするところは、ライトバルブに
できるだけ高照度比で光束を入射させ、しかも利用効率
の高い照明装置を提供することにある。Therefore, the present invention solves such a problem, and an object of the present invention is to provide a lighting device which allows a light beam to enter a light valve at a high illuminance ratio as high as possible and has high utilization efficiency. It is in.

【０００５】[0005]

【課題を解決するための手段】本発明の照明装置は、点
光源に近い光源ランプと該光源ランプからの放射光束を
被照射面へ反射する反射鏡を備えてなる照明装置であ
り、前記被照射面はその中心と光源の中心を結ぶ光軸に
対し垂直な円形被照射面であって、前記反射鏡が、光源
近傍にある光軸上の点を第１焦点とし円形被照射面上の
任意の端点を第２焦点とする楕円曲線を光軸の回りに回
転させた形状の、回転傾楕円鏡であることを特徴とす
る。An illuminating device of the present invention is a illuminating device comprising a light source lamp close to a point light source and a reflecting mirror for reflecting a light beam emitted from the light source lamp to an illuminated surface. The irradiation surface is a circular irradiation surface that is perpendicular to the optical axis connecting the center of the irradiation surface to the center of the light source, and the reflecting mirror has a point on the optical axis near the light source as the first focal point on the circular irradiation surface. It is characterized in that the elliptic curve having an arbitrary end point as the second focal point is rotated around the optical axis to form a rotationally tilted elliptical mirror.

【０００６】また前記光源ランプと前記被照射面の間に
光束を透過散乱させる板状部材を配していることを特徴
とする。この実施例として、透過散乱性の板状部材が高
分子分散型液晶であることを特徴とする。Further, a plate-like member which transmits and scatters a light beam is arranged between the light source lamp and the illuminated surface. This embodiment is characterized in that the transmission-scattering plate-like member is a polymer-dispersed liquid crystal.

【０００７】また前記光源ランプと前記被照射面の間に
非球面レンズを配していることを特徴とする。An aspherical lens is arranged between the light source lamp and the illuminated surface.

【０００８】本発明による投射型表示装置は、白色光源
を含む照明装置と、該照明装置からの光束を変調するラ
イトバルブと、変調光束を投射する投射レンズにより構
成され、前記照明装置が上に述べた照明装置であって、
また前記ライトバルブが円形被照射面に内接する様に配
されていることを特徴とする。The projection type display device according to the present invention comprises an illuminating device including a white light source, a light valve for modulating a light beam from the illuminating device, and a projection lens for projecting the modulated light beam. A lighting device as described above,
Further, the light valve is arranged so as to be inscribed on the circular irradiation surface.

【０００９】[0009]

【実施例】以下、本発明による照明装置について、図面
に基づき詳細に説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An illumination device according to the present invention will be described below in detail with reference to the drawings.

【００１０】図１（Ａ）は、本発明の照明装置に用いる
反射鏡の形状を示す断面模式図である。反射鏡１２の断
面のうちの一方、例えば本図における上側の断面は、光
源１１の近傍にある光軸１４上の点を第１焦点１６と
し、被照射面１３上の端点を第２焦点１７ａとする楕円
１５上の曲線となっている。またもう一方の断面も同様
に同じ第１焦点１６と被照射面の端点を第２焦点１７ｂ
とする楕円１５上の曲線である。即ち本反射鏡は、長軸
が光軸１４に対して傾いた楕円１５の一部を光軸１４の
回りに回転させた形状（以下、この形状を回転傾楕円面
と呼ぶ）をもっている。FIG. 1A is a schematic sectional view showing the shape of a reflecting mirror used in the illuminating device of the present invention. One of the cross sections of the reflecting mirror 12, for example, the cross section on the upper side in this figure, has a point on the optical axis 14 near the light source 11 as the first focus 16 and an end point on the illuminated surface 13 as the second focus 17a. Is a curve on the ellipse 15. Similarly, for the other cross-section, the same first focal point 16 and the end point of the illuminated surface are set to the second focal point 17b.
Is a curve on the ellipse 15. That is, the present reflecting mirror has a shape in which a part of the ellipse 15 whose major axis is tilted with respect to the optical axis 14 is rotated around the optical axis 14 (hereinafter, this shape is referred to as a rotational tilt ellipsoidal surface).

【００１１】この様な反射鏡１２に対して光源１１はそ
の端部が第１焦点１６にほぼ接する様に被照射面側に配
置される。光源１１としては、キセノンランプ，メタル
ハライドランプ，ハロゲンランプなどが用いられ、例え
ばメタルハライドランプではその放電アークの形状が円
筒形状で近似されるので、その底面の中心をほぼ第１焦
点１６に接する様に、また光軸に対して対称に配置す
る。With respect to such a reflecting mirror 12, the light source 11 is arranged on the irradiated surface side so that its end portion is substantially in contact with the first focal point 16. As the light source 11, a xenon lamp, a metal halide lamp, a halogen lamp, or the like is used. For example, in a metal halide lamp, the shape of the discharge arc is approximated by a cylindrical shape, so that the center of the bottom surface of the lamp is in contact with the first focal point 16. , And are arranged symmetrically with respect to the optical axis.

【００１２】この時、被照射面がどの様に照明されるか
を図１（Ｂ）で説明する。図１（Ａ）に示したａ点に接
する微小反射面で反射された光束は、被照射面１３上に
放電アークの像１８ａを描き、被照射面１３の枠に接し
ている。同様にｂ点，ｃ点に接する微小反射面による放
電アークの像１８ｂ，１８ｃを描き、やはり被照射面１
３の枠に接する。従って放射光束のうち反射鏡１２で反
射された光束は特別な場合を除いてすべて被照射面内に
入射し、枠付近の照度は可能な中では最も高照度であ
る。被照射面１３内での照度分布は、光源１１の形状，
反射鏡１２の開口径，楕円曲線１５の長軸長と短軸長，
被照射面１３までの距離，被照射面の半径など、多くの
パラメータによって変化する。そこで各パラメータを適
当に変化させることによって、照度分布をほぼ一定に選
ぶことが出来るので、この様な照明系では、高利用率で
ほぼ均一な理想照明を実現できる。At this time, how the illuminated surface is illuminated will be described with reference to FIG. The light flux reflected by the minute reflecting surface in contact with the point a shown in FIG. 1A draws an image 18 a of the discharge arc on the illuminated surface 13 and is in contact with the frame of the illuminated surface 13. Similarly, images 18b and 18c of the discharge arc by the minute reflecting surfaces in contact with the points b and c are drawn, and the irradiated surface 1 is also shown.
Touch the frame of 3. Therefore, of the radiated luminous flux, all the luminous flux reflected by the reflecting mirror 12 is incident on the surface to be illuminated except for a special case, and the illuminance near the frame is the highest illuminance possible. The illuminance distribution within the illuminated surface 13 is determined by the shape of the light source 11,
The aperture diameter of the reflecting mirror 12, the major axis length and the minor axis length of the elliptic curve 15,
It depends on many parameters such as the distance to the irradiated surface 13 and the radius of the irradiated surface. Therefore, by appropriately changing each parameter, the illuminance distribution can be selected to be almost constant, and thus such an illumination system can realize ideal illumination with high utilization.

【００１３】ところが、投射型表示装置に応用しようと
すると、各パラメータは自ずと決まる場合が多く、被照
射面の中心照度が最も高くなりやすい。一般に照度比が
４０％程度であれば、さほど表示品質を悪化させないと
言われるが、許容範囲を超えて中心照度が高い場合にお
いては、図３に示すように、反射鏡１２と液晶ライトバ
ルブ２５の間に、光束を透過散乱させる板状部材３１を
配すればよい。この板状部材３１には、例えば中心部を
梨地状にしたガラス板を用いる。そうすると液晶ライト
バルブ２５の周辺部に向かう光束はそのまま透過し、中
心部に向かう光束は透過散乱部３２によって、ガラス板
の凹凸度合に応じた散乱状態となって透過する。したが
って、中心部へ向かう光束の一部は周辺に振り分けら
れ、あるいは投射レンズに呑込まれないほど角度がつい
てしまうので、結果として照度比が高くなる。However, when it is applied to a projection type display device, each parameter is often determined by itself, and the central illuminance of the illuminated surface tends to be the highest. Generally, if the illuminance ratio is about 40%, it is said that the display quality is not so deteriorated. However, when the illuminance ratio exceeds the allowable range and the central illuminance is high, as shown in FIG. A plate-like member 31 that transmits and scatters the light flux may be disposed between the two. The plate-shaped member 31 is, for example, a glass plate having a satin-finished central portion. Then, the light flux toward the peripheral portion of the liquid crystal light valve 25 is transmitted as it is, and the light flux toward the center portion is transmitted by the transmission / scattering unit 32 in a scattering state according to the degree of unevenness of the glass plate. Therefore, a part of the light flux heading to the central portion is distributed to the periphery or is angled so as not to be swallowed by the projection lens, resulting in a high illuminance ratio.

【００１４】照度比を可変とするには、光束を透過散乱
させる板状部材３１として、高分子分散型液晶（以下、
ＰＤＬＣと略す）を用いればよい。ＰＤＬＣを用いれ
ば、その透過散乱度合を、電圧によって変化させること
が出来るので、それに伴って照度比が変化する。In order to make the illuminance ratio variable, a polymer dispersion type liquid crystal (hereinafter
(Abbreviated as PDLC) may be used. If PDLC is used, the degree of transmission and scattering can be changed by the voltage, so that the illuminance ratio changes accordingly.

【００１５】また図４の様に、反射鏡１２と液晶ライト
バルブ２５の間に非球面レンズ４１を配してもよい。こ
の場合は液晶ライトバルブ２５の中心部に入射しようと
する光束が周辺部に広げられるので、最適な形状にすれ
ば照度分布をかなり均一にすることが出来る。本発明に
おける回転傾楕円鏡の形状を数式を用いて定義してお
く。図５に示すように、第１焦点１６と被照射面１３間
の距離をｌ、被照射面の半径をｄ、楕円１５の長軸長を
２ａ、短軸長を２ｂ、長軸と光軸１４間の角度をθとす
るとき、ｘｙｚ座標系（ｚ軸は第１焦点１６を通り紙面
に垂直）において、反射鏡１２上の任意の点（ｘ₁，
ｙ₁，ｚ₁）は、 Ｆ（ｘ，ｙ，ｚ） ≡ｂ²｛ｘｃｏｓθ＋√（ｙ²＋ｚ²）ｓｉｎθ−ｃ｝ ＋ａ²（−ｘｓｉｎθ＋√（ｙ²＋ｚ²）ｃｏｓθ｝²−ａ²ｂ² ＝０ を満たしている。ここで、ｃは第１焦点１６と第２焦点
１７ａの距離の１／２で、 ｃ＝０．５√（ｌ²＋ｄ²）＝√（ａ²−ｂ²） と表わせる。また、 ｓｉｎθ＝ｄ／√（ｌ²＋ｄ²） ｃｏｓθ＝ｌ／√（ｌ²＋ｄ²） である。As shown in FIG. 4, an aspherical lens 41 may be arranged between the reflecting mirror 12 and the liquid crystal light valve 25. In this case, since the light flux that is about to enter the central portion of the liquid crystal light valve 25 is spread to the peripheral portion, it is possible to make the illuminance distribution fairly uniform by using an optimum shape. The shape of the rotary ellipsoidal mirror in the present invention is defined by using mathematical expressions. As shown in FIG. 5, the distance between the first focus 16 and the illuminated surface 13 is 1, the radius of the illuminated surface is d, the major axis length of the ellipse 15 is 2a, the minor axis length is 2b, and the major axis and the optical axis. When the angle between 14 is θ, in the xyz coordinate system (the z-axis passes through the first focal point 16 and is perpendicular to the paper surface), an arbitrary point (x ₁ ,
y ₁ , z ₁ ) is F (x, y, z) ≡b ² {xcos θ + √ (y ² + z ² ) sin θ−c} + a ² (−xsin θ + √ (y ² + z ² ) cos θ} ² −a ² b ² = 0 is satisfied, where c is ½ of the distance between the first focus 16 and the second focus 17a, and c = 0.5√ (l ² + d ² ) = √ (a ² −b ² ) and sin θ = d / √ (l ² + d ² ) cos θ = l / √ (l ² + d ² ).

【００１６】[0016]

【発明の効果】以上述べたように本発明によれば、回転
傾楕円鏡を用いてライトバルブを照射するので、ライト
バルブの四隅が可能な限り高照度で照明され、しかも光
束の利用効率が極めて高い。従って、映像が隅々まで明
るく高品位な投射型表示装置を実現できる。As described above, according to the present invention, since the light valve is illuminated by using the rotary ellipsoidal mirror, the four corners of the light valve are illuminated with the highest possible illuminance, and the utilization efficiency of the luminous flux is improved. Extremely high. Therefore, it is possible to realize a high-quality projection display device in which the image is bright in every corner.

【図面の簡単な説明】[Brief description of drawings]

【図１】（Ａ）本発明の照明装置における反射鏡の形状
を示す断面模式図。 （Ｂ）本発明による反射鏡の照明原理を示した図。FIG. 1A is a schematic cross-sectional view showing the shape of a reflecting mirror in a lighting device of the present invention. (B) The figure which showed the illumination principle of the reflecting mirror by this invention.

【図２】（Ａ）従来の投射型表示装置に用いられた照明
装置の構成を示す図。 （Ｂ）従来構成における、ライトバルブ上の照度分布を
示す図。FIG. 2A is a diagram showing a configuration of an illumination device used in a conventional projection display device. (B) A diagram showing an illuminance distribution on a light valve in a conventional configuration.

【図３】本発明を投射型表示装置に用いた場合の構成例
を示す図。FIG. 3 is a diagram showing a configuration example when the present invention is applied to a projection type display device.

【図４】本発明を投射型表示装置に用いた場合の構成例
を示す図。FIG. 4 is a diagram showing a configuration example when the present invention is applied to a projection type display device.

【図５】本発明における反射鏡の形状を数式で定義する
ための図。FIG. 5 is a diagram for defining the shape of a reflecting mirror in the present invention by a mathematical expression.

【符号の説明】[Explanation of symbols]

１１ 光源 １２ 反射鏡 １３ 被照射面 １４ 光軸 １５ 楕円 １６ 第１焦点 １７ａ，１７ｂ 第２焦点 １８ａ，１８ｂ，１８ｃ 微小反射面による放電アーク
の像 ２１ 光源ランプ ２２ 回転放物鏡 ２３ 反射光束 ２４ 集光レンズ ２５ 液晶ライトバルブ ２６ 投射レンズ ２７ スクリーン ３１ 透過散乱性板状部材 ３２ 透過散乱部 ４１ 非球面レンズ11 Light Source 12 Reflecting Mirror 13 Irradiated Surface 14 Optical Axis 15 Ellipse 16 First Focus 17a, 17b Second Focus 18a, 18b, 18c Image of Discharge Arc by Micro Reflecting Surface 21 Light Source Lamp 22 Rotating Parabolic Mirror 23 Reflected Luminous Flux 24 Focused Lens 25 Liquid crystal light valve 26 Projection lens 27 Screen 31 Transmission / scattering plate member 32 Transmission / scattering part 41 Aspherical lens

Claims (1)

【特許請求の範囲】 【請求項１】 点光源に近い光源ランプと該光源ランプ
からの放射光束を被照射面へ反射する反射鏡を備えてな
る照明装置において、前記被照射面はその中心と光源の
中心を結ぶ光軸に対し垂直な円形被照射面であり、前記
反射鏡が、光源近傍にある光軸上の点を第１焦点とし円
形被照射面上の任意の端点を第２焦点とする楕円曲線を
光軸の回りに回転させた形状の、回転傾楕円鏡であるこ
とを特徴とする照明装置。 【請求項２】 前記光源ランプと前記被照射面の間に光
束を透過散乱させる板状部材を配していることを特徴と
する請求項１に記載の照明装置。 【請求項３】 前記光束を透過散乱させる板状部材が高
分子分散型液晶であることを特徴とする請求項２に記載
の照明装置。 【請求項４】 前記光源ランプと前記被照射面の間に非
球面レンズを配していることを特徴とする請求項１に記
載の照明装置。 【請求項５】 白色光源を含む照明装置と、該照明装置
からの光束を変調するライトバルブと、変調光束を投射
する投射レンズにより構成される投射型表示装置におい
て、前記照明装置が、請求項１，２，３または４に記載
の照明装置であり、また前記ライトバルブが前記円形被
照射面に内接する様に配されていることを特徴とする投
射型表示装置。Claim: What is claimed is: 1. An illumination device comprising a light source lamp close to a point light source and a reflecting mirror for reflecting a luminous flux emitted from the light source lamp to a surface to be irradiated, wherein the surface to be irradiated is the center thereof. A circular illuminated surface that is perpendicular to the optical axis connecting the centers of the light sources, and the reflecting mirror has a point on the optical axis near the light source as a first focal point and an arbitrary end point on the circular illuminated surface as a second focal point. An illuminating device characterized by being a rotating tilt ellipsoidal mirror having a shape obtained by rotating an elliptic curve around the optical axis. 2. The illumination device according to claim 1, further comprising a plate-shaped member that transmits and scatters a light flux between the light source lamp and the illuminated surface. 3. The illumination device according to claim 2, wherein the plate-shaped member that transmits and scatters the light flux is a polymer-dispersed liquid crystal. 4. The illuminating device according to claim 1, further comprising an aspherical lens disposed between the light source lamp and the illuminated surface. 5. A projection type display device comprising a lighting device including a white light source, a light valve for modulating a light flux from the lighting device, and a projection lens for projecting the modulated light flux, wherein the lighting device comprises: 5. The projection display device according to any one of 1, 2, 3 and 4, wherein the light valve is arranged so as to be inscribed in the circular illuminated surface.