JP2011119118A - Lighting device and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device easily parallelizing and thinning luminous flux, and also to provide a projector using the lighting device. <P>SOLUTION: In the lighting device 10, the luminous flux is converted into parallel light since a shape of a horizontal cross section HS of a concave mirror 22b is a parabolic arc, and the luminous flux is converted into convergent light since a shape of a vertical cross section PS of the concave mirror 22b is an ellipse-like arc. Thickness dimensions D of the concave mirror 22b is shortened in this case. Thus, thinning of the lighting device 10 is easily performed. A parallelizing lens 21b is relatively inexpensive since the parallelizing lens 21b at a latter stage becomes a cylindrical shape by parallelizing the luminous flux in the horizontal direction. Thinning of the projector using the lighting device 10 is attained easily. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an illumination device having a reflecting mirror that reflects light from an arc tube and a projector using the same.

  As an illumination device for a projector, it has an ellipsoidal reflector (reflecting mirror), and has a rotationally asymmetric reflection in which the shape of a vertical section including the central axis of the reflector and the shape of a horizontal section are different from each other. It has been known to reduce the thickness of an apparatus by using a surface (see Patent Document 1).

JP 2009-54340 A

  However, in the case of Patent Document 1, for example, in the collimation of the light beam to be suitable for the illumination light of the projector, it is possible to correspond to both the curvature of the shape of the vertical section of the reflector and the curvature of the shape of the horizontal section. Necessary. In this case, for example, in order to collimate the light beam using a concave lens, the curved surface shape of the concave lens must be made quite complicated.

  SUMMARY An advantage of some aspects of the invention is that it provides an illuminating device capable of easily collimating and thinning a light beam and a projector using the same.

  In order to solve the above-described problems, a first lighting device according to the present invention includes (a) a light emitting tube that generates light, and (b1) a shape that is cut by two planes that perpendicularly intersect each other including the system optical axis. The shape cut by one plane draws a parabolic arc whose focal point is the center between the electrodes of the arc tube, and the shape cut by the other plane has the focal point of the parabolic arc as the first focal point. A reflecting surface having a non-rotationally symmetric shape that draws an elliptical arc, and (b2) an anamorphic reflecting mirror that reflects light from the arc tube by the reflecting surface and emits illumination light. .

  In the first lighting device, on the reflecting surface of the anamorphic reflector, the shape cut out on the one plane draws a parabolic arc, and the shape cut off on the other plane draws an elliptical arc. ing. Thereby, about said one plane, a light beam can be collimated beforehand by the shape which draws a parabolic arc. That is, with respect to the one plane, it is possible to configure the latter optical component used for collimating the light beam with a relatively inexpensive one. In addition, since the other plane has a shape that draws an elliptical arc, the dimension in the direction perpendicular to the system optical axis can be made relatively short to reduce the thickness of the lighting device.

  Further, according to a specific aspect or side surface of the present invention, the non-rotationally symmetric shape of the reflecting surface gradually changes from a parabolic shape to an elliptical shape from the one plane toward the other plane. Shape. In this case, the continuous curved surface shape gradually changes without a step, so that the uniformity of the light flux related to the angular distribution can be improved, and a light flux suitable for forming illumination light is emitted.

  According to another aspect of the present invention, the illuminating device includes a collimating lens that is arranged on the downstream side of the light path of the arc tube and the anamorphic reflector and has a cylindrical aspherical surface to collimate light passing therethrough. Further prepare. In this case, the passing light beam can be collimated by a collimating lens having a relatively simple shape.

  According to another aspect of the present invention, in the collimating lens, the generating line of the cylindrical aspheric surface extends in a direction parallel to the plane perpendicular to the system optical axis and parallel to the one plane. In this case, when the light beam passes through the collimating lens, the parallelism of the light beam can be maintained with respect to the plane parallel to the one plane.

  According to another aspect of the present invention, the collimating lens has a hyperboloid on the light incident side as a cylindrical aspherical surface. In this case, when the light beam passes through the collimating lens, the light beam can be accurately collimated with respect to a plane parallel to the other plane.

  According to another aspect of the present invention, the collimating lens has either a flat surface or a cylindrical spherical surface on the light exit side. In this case, the collimating lens can collimate the light beam by the refractive power only on the light incident side or the refractive power obtained by combining the light incident side and the light exit side.

  According to another aspect of the present invention, the arc tube has an auxiliary reflector that reflects light emitted from the center between the electrodes of the arc tube to the opposite side of the anamorphic reflector in the reverse direction. In this case, it is possible to effectively recover the light beam directly emitted to the downstream side of the optical path, and it is possible to improve the light utilization efficiency.

  According to another aspect of the present invention, the auxiliary reflecting mirror has a reflecting surface that is wider in a region corresponding to the one plane than in a region corresponding to the other plane. In this case, it is possible to preferentially increase the utilization efficiency of light incident on a parabolic arc-shaped surface that tends to have a relatively low light uptake rate or on a peripheral surface thereof.

  According to another aspect of the present invention, the auxiliary reflecting mirror is formed by directly coating a part of the light transmitting portion of the arc tube. In this case, the auxiliary reflecting mirror can be manufactured relatively easily.

  In order to solve the above-described problem, a second lighting device according to the present invention includes (a) an arc tube that generates light, and (b) one of two planes that include the system optical axis and perpendicularly intersect each other. A reflecting surface that reflects the light beam from the arc tube as parallel light when viewed from the direction perpendicular to the light source and reflects the light beam from the arc tube as convergent light when viewed from the direction perpendicular to the other plane. And a reflecting mirror.

  In the second illumination device, the anamorphic reflecting surface reflects the light beam from the arc tube as parallel light when viewed from the direction perpendicular to the one plane, and from the direction perpendicular to the other plane. When viewed, the light beam from the arc tube is reflected so as to be convergent light. Thereby, the dimension of the apparatus in said other plane can be shortened, and thickness reduction of an illuminating device can be achieved. At this time, since the one plane is already parallelized, the optical component on the downstream side of the optical path can be configured with a relatively inexpensive one.

  In order to solve the above-described problems, a projector according to the present invention includes (a) any one of the above illumination devices, (b) a light modulation device that is illuminated by a light beam emitted from the illumination device, and (c) a light modulation. A projection optical system that projects a light beam emitted from the apparatus. In this case, by using any one of the above illumination devices, the projector as a whole can be easily reduced in thickness.

It is a top view which shows notionally the projector incorporating the illuminating device which concerns on 1st Embodiment. (A), (B) is the horizontal sectional view and vertical sectional view of the illuminating device which concern on 1st Embodiment. (A), (B) is a figure which shows the mode of the light beam in the horizontal cross section and vertical cross section of an illuminating device. It is a perspective view which shows the reflective mirror of an illuminating device. It is a front view which shows typically the lens array of an illuminating device. It is a figure of the light beam cross-section inject | emitted from an illuminating device. (A), (B) is a figure which shows the modification of the parallelizing lens of an illuminating device. (A), (B) is sectional drawing for demonstrating an example of the illuminating device which concerns on 2nd Embodiment. (A), (B) is sectional drawing for demonstrating an example of the illuminating device which concerns on 3rd Embodiment. (A), (B) is sectional drawing for demonstrating another example of the illuminating device which concerns on 3rd Embodiment.

[First Embodiment]
Hereinafter, with reference to FIG. 1 etc., the illuminating device which concerns on 1st Embodiment of this invention, and a projector using the same are demonstrated.

  As shown in FIG. 1, a projector 100 incorporating the illumination device 10 according to the present embodiment includes, in addition to the illumination device 10, a color separation light guide unit 40, a light modulation unit 50, a color synthesis unit 60, and a projection optical system. 70.

  First, the illumination device 10 is an illumination optical system including a light source lamp unit 20 and a uniformizing optical system 30. The light source lamp unit 20 includes a lamp unit 21a and a collimating lens 21b which is a concave cylindrical lens as a light source. The lamp unit 21a includes an arc tube 22a, a concave mirror 22b, and a sub mirror 23a.

  As shown in FIG. 2 (A) and the like, in the light source lamp unit 20, the arc tube 22a includes a tube portion PB made of translucent quartz glass having a spherical central portion, and a tube portion PB of the tube portion PB. Mercury, a rare gas, and a small amount of halogen are sealed inside the tube portion PB having first and second sealing portions 24a and 24b extending on both end sides and sealed by the sealing portions 24a and 24b. ing. The center between the electrodes of a pair of electrodes (not shown) arranged in the tube portion PB serves as a light emission point EP to generate light radially. Various arc tubes can be adopted as the arc tube 22a, for example, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, or the like.

  The concave mirror 22b is an anamorphic reflecting mirror that reflects the light beam emitted from the arc tube 22a and emits it forward. The reflecting surface RF of the concave mirror 22b is about one of the two planes perpendicular to each other including the system optical axis SA, that is, the first plane (XZ plane including the system optical axis SA) shown in FIG. The horizontal section HS cut out and the vertical section PS cut out about the other plane shown in FIG. 2B, that is, the second plane (YZ plane including the system optical axis SA) have different curved shapes. . More specifically, first, the shape of the reflecting surface RFa of the concave mirror 22b in the horizontal section HS is a parabolic shape with the light emitting point EP as a focal point. On the other hand, the shape of the reflection surface RFb of the concave mirror 22b in the vertical section PS is an elliptical shape having the light emission point EP on the system optical axis SA as the first focal point. As a result, as shown in FIG. 3A, on the XZ plane including the system optical axis SA, the light beam emitted from the light emitting point EP toward the reflecting surface RFa is reflected by the reflecting surface RFa and then collimated. It is injected in the state made. On the other hand, as shown in FIG. 3B, on the YZ plane including the system optical axis SA, the light beam emitted from the light emitting point EP toward the reflective surface RFb is reflected by the reflective surface RFb and then the system optical axis. The light is emitted so as to converge to the second focal point F2 on the SA. Furthermore, the light beam emitted from the light emitting point EP is also reflected at the corresponding portion of the reflecting surface RF at an intermediate location other than the horizontal section HS and the vertical section PS of the concave mirror 22b, and is reflected on the XZ plane including the system optical axis SA. When projected, the light beam is parallel to the system optical axis SA, and when projected onto the YZ plane including the system optical axis SA, the light beam exits in a state of being converged to the second focal point F2 on the system optical axis SA. Is done. That is, the concave shape of the reflection surface RF of the concave mirror 22b is continuously changed from the parabolic reflection surface RFa to the elliptical reflection surface RFb. That is, the reflection surface RF is a curved surface that changes continuously without a step, and has a non-rotationally symmetric shape as a whole.

  As shown in FIG. 2A and the like, the secondary mirror 23a is inserted and fixed to the second sealing portion 24b on the opposite side of the concave mirror 22b so as to face the concave mirror 22b. The part PB covers substantially half of the opposite side of the concave mirror 22b. The secondary mirror 23a has a spherical reflecting surface RR, and among the light radiated from the arc tube 22a, the light beam directly directed to the parallel collimating lens 21b, that is, the light that does not go to the concave mirror 22b, Then, the light-emitting point EP or its periphery is allowed to pass through and is incident on the reflecting surface RF of the concave mirror 22b. That is, the sub mirror 23a functions as an auxiliary reflecting mirror that reflects the light emitted from the arc tube 22a to the side opposite to the concave mirror 22b so as to reversely travel, thereby increasing the light use efficiency.

  The collimating lens 21b is a lens that is disposed in the illuminated region on the downstream side of the optical path of the lamp unit 21a, and has a role of making the light beam from the lamp unit 21a a light beam substantially parallel to the system optical axis SA, that is, the illumination optical axis. is there. For this reason, the focal point of the collimating lens 21b coincides with the second focal point F2 of the reflecting surface RF. The light incident surface IS of the collimating lens 21b is a cylindrical aspherical surface, and is linear in the horizontal direction, that is, the X direction, as shown in FIG. 2A, and as shown in FIG. It is a hyperbolic shape corresponding to the shape of the reflecting surface RFb in the vertical direction, that is, the Y direction. That is, the generatrix of the light incident surface IS extends in a direction parallel to the XY plane perpendicular to the system optical axis SA and parallel to the first plane, that is, the XZ plane including the system optical axis (that is, the X direction). . The light exit surface ES of the collimating lens 21b is a plane extending in parallel to the XY plane perpendicular to the system optical axis SA. Since the collimating lens 21b has the above-described surface shape, as shown in FIGS. 3 (A) and 3 (B), the total luminous flux emitted from the lamp unit 21a is aligned along the direction of the system optical axis SA. And inject in a substantially parallel state.

  Returning to FIG. 1, the homogenizing optical system 30 includes first and second lens arrays 31 and 32, a polarization conversion member 34, and a superimposing lens 35. The first and second lens arrays 31 and 32 are, for example, fly-eye lenses each composed of a plurality of element lenses arranged in a matrix. Among these, the luminous flux emitted from the light source lamp unit 20 is divided into a plurality of partial luminous fluxes by the element lenses constituting the first lens array 31. Further, the partial lenses from the first lens array 31 are emitted at an appropriate divergence angle by the element lenses constituting the second lens array 32. The polarization conversion member 34 is configured by a prism array or the like in which prism elements PE made of PBS, retardation plates, etc. extending in the X direction are arranged in the Y direction, and the light beam emitted from the lens array 32 is converted to only linearly polarized light in a specific direction. Converted and supplied to the next stage optical system. The superimposing lens 35 appropriately superimposes the illumination light emitted from the second lens array 32 and passing through the polarization conversion member 34 as a whole, thereby superimposing illumination on the liquid crystal light valves 50a, 50b, and 50c of each color provided in the light modulation unit 50. Enable. As described above, the illumination device 10 emits illumination light in a state suitable for projection image formation by the projector 100.

  As shown in FIGS. 2A and 2B, the lens arrays 31 and 32, the polarization conversion member 34, and the superimposing lens 35 all match the cross-sectional shape of the light beam emitted from the collimating lens 21b. It has a horizontally long flat shape that is short in the Y direction and long in the X direction.

ｋ_ｘ，ｋ_ｙ：コーニック定数、ｃ_ｘ，ｃ_ｙ：半径の逆数、
Ａ_２ｎ：対称係数、Ｂ_２ｎ：非対称係数
に基づいて、上記焦点距離を実現するように各係数等を選定することで決定される。ここで、各コーニック定数ｋ_ｘ，ｋ_ｙは、−１＜ｋ_ｘ＜０の範囲内にあり、ｋ_ｙ＝−１（固定）である。また、ｃ_ｘ，ｃ_ｙに対応する半径は、第1焦点が一致するように調整する必要がある。上記アナモフィック非球面のシミュレーションに際して、反射面ＲＦｃの曲面形状に関する各係数は、ＸＺ面に垂直なＹ方向から見た場合には反射光が平行光となり、ＹＺ面に垂直なＸ方向から見た場合には反射光が収束光となるように定められている。なお、反射面ＲＦｃの曲面形状は、反射面ＲＦａ，ＲＦｂの焦点距離等の条件を前提としており、反射面ＲＦｃは、反射面ＲＦａ，ＲＦｂと滑らかにつながる。以上のようにして、反射面ＲＦａ，ＲＦｂ及び反射面ＲＦｃを設定することにより、図２（Ａ）等に示す発光点ＥＰから射出された光束は、反射面ＲＦａ，ＲＦｂ上で反射されるものに限らず反射面ＲＦｃまで含めた反射面ＲＦ上全体において、Ｙ方向から見ると平行光となり、Ｘ方向から見ると第２焦点Ｆ２に向かう収束光となるようにランプ部２１ａから射出される。凹面鏡２２ｂの具体的な作製方法については、上記のようなシミュレーション結果を基にして反転した形状の金型を作製する。この金型を利用して加熱したガラス材料等をプレス加工し、反射膜を形成することにより、上記のような特殊な形状の反射面ＲＦを有する凹面鏡２２ｂが作製される。なお、±Ｘ方向と±Ｙ方向との中間を含む反射面ＲＦａ，ＲＦｂ，ＲＦｃの形状は、全体として円形の輪郭を有する滑らかな連続曲面であるため、後述する液晶パネル５１ａ，５１ｂ，５１ｃ（図１参照）に入射する光は、入射角度の方位依存性を抑えた一様性の高いものであり、プロジェクター１００による画像投影に適したものとなっている。 Hereinafter, main components of the illumination device 10 will be described in detail. As shown in FIG. 4, the reflecting surface RF of the concave mirror 22b has a step gradually from a parabolic shape to an elliptical shape from the horizontal section HS to the vertical section PS on the reflecting surface RFc other than the reflecting surfaces RFa and RFb. It has changed without having a smooth continuous curved surface as a whole. Here, the shapes of the reflection surfaces RFa and RFb in the cross sections HS and PS are, for example, a parabolic focal length f = 12 on the reflection surface RFa, an elliptical first focal length f1 = 12, and a second focal length on the reflection surface RFb. It is set so that f2 = 60. Further, the specific curved surface shape of the reflecting surface RFc other than the reflecting surfaces RFa and RFb is the following sag amount expression of the anamorphic aspheric surface.

k _x , k _y : conic constant, c _x , c _y : reciprocal of radius,
A _2n is determined by selecting each coefficient or the like so as to realize the focal length based on a symmetric coefficient and B _2n : an asymmetric coefficient. Here, each of the conic constants k _x and k _y is in the range of −1 <k _x <0, and k _y = −1 (fixed). Further, a radius corresponding to the c _x, c _y must be adjusted such that the first focal point is coincident. In the simulation of the anamorphic aspherical surface, each coefficient relating to the curved surface shape of the reflective surface RFc is obtained when the reflected light becomes parallel light when viewed from the Y direction perpendicular to the XZ plane and when viewed from the X direction perpendicular to the YZ plane. Is defined so that the reflected light becomes convergent light. The curved surface shape of the reflection surface RFc is based on conditions such as the focal length of the reflection surfaces RFa and RFb, and the reflection surface RFc is smoothly connected to the reflection surfaces RFa and RFb. By setting the reflection surfaces RFa and RFb and the reflection surface RFc as described above, the light beam emitted from the light emission point EP shown in FIG. 2A and the like is reflected on the reflection surfaces RFa and RFb. In addition, the entire reflecting surface RF including the reflecting surface RFc is emitted from the lamp unit 21a so as to be parallel light when viewed from the Y direction and convergent light toward the second focal point F2 when viewed from the X direction. As for a specific method of manufacturing the concave mirror 22b, a mold having an inverted shape is manufactured based on the simulation result as described above. A concave mirror 22b having the reflection surface RF having a special shape as described above is manufactured by pressing a heated glass material or the like using this mold to form a reflection film. Note that the shapes of the reflection surfaces RFa, RFb, and RFc including the middle between the ± X direction and the ± Y direction are smooth continuous curved surfaces having a circular outline as a whole. The light incident on (see FIG. 1) is highly uniform with the azimuth dependency of the incident angle suppressed, and is suitable for image projection by the projector 100.

  Further, the collimating lens 21b shown in FIG. 2B and the like has a hyperbolic curved surface corresponding to the shape of the vertical section PS of the concave mirror 22b. That is, in FIG. 3B and the like, the incident surface IS of the collimating lens 21b is a hyperbola corresponding to the shape of the reflecting surface RFb, and the collimating lens 21b has a refractive power at the incident surface IS. Therefore, the second focal point F2 has a common focal point with the second focal point F2. The numerical value that can be specifically applied to the hyperbola in the Y direction (vertical direction) of the collimating lens 21b is, for example, a conical constant value ranging from −1.5 to −4.0 depending on the installation position. The conical constant K = −2.5 and the paraxial radius of curvature r = 8 can correspond to the concave mirror 22b having the above shape. The refractive index of the collimating lens 21b is determined so that the focal point of the collimating lens 21b coincides with the focal point of the second focal point F2 of the concave mirror 22b due to refraction at the entrance surface IS or the like. The collimating lens 21b is a cylindrical lens, and has no refractive power in the X direction (horizontal direction). The collimating lens 21b having the light incident surface IS as described above can collimate the light beam that converges on the second focal point F2. Here, as described above, since the collimating lens 21b has a uniform cylindrical shape in the X direction, the processing of the lens surface, that is, the incident surface IS is relatively easy. The lens 21b can be manufactured at a very low cost compared to, for example, manufacturing an aspheric lens.

  Further, as shown in FIG. 5, the first lens array 31 has a configuration in which twelve element lenses 31a are arranged in a matrix in which four element lenses 31a are arranged in the X direction and three in the Y direction. That is, the first lens array 31 divides the incident light flux into four parts in the X direction and three parts in the Y direction by the element lenses 31a. Each element lens 31a has a rectangular outline (for example, an aspect ratio of 16: 9) substantially similar to the effective area of the liquid crystal panels 51a, 51b, and 51c, that is, the shape of the projected image. At this time, as shown in FIG. 6, the shape of the light beam cross-section FF when entering the collimating lens 21b or the first lens array 31 is an extremely horizontally long flat shape having an aspect ratio of 2: 1 or more (that is, depending on the X direction). Long rectangle). Here, it is necessary for the element lens 31a of the first lens array 31 to match the number of divisions in the X direction with the prism elements PE constituting the prism array of the polarization conversion member 34. There is no need. If the number of divisions is large, the light use efficiency may be reduced. In the case of the present embodiment, by making the shape of the light beam cross-section FF flat, the number of divisions (3) in the Y direction of the element lens 31a may be less than the number of divisions in the X direction (4). it can. Thereby, the fall of the utilization efficiency of light can be suppressed.

  The shape (aspect ratio) of the light beam cross section FF can be appropriately adjusted depending on the distance from the light source unit and the like. In the case shown in FIG. 6, due to the presence of the arc tube 22a and the secondary mirror 23a, a shadow SD is formed somewhat in the central portion of the light beam section FF. You may arrange | position by the positional relationship which collimates with a cylindrical lens and injects into the 1st lens array 31. FIG. In this case, the shadow SD at the center of the light beam section FF can be weakened as compared with the case shown in FIG.

  Further, as shown in FIGS. 7A and 7B as modifications, the shape of the collimating lens 21b is a hyperbolic cylindrical aspheric surface on the light incident surface IS side, and a cylindrical shape on the light exit surface ES side. By adopting a cylindrical spherical surface, the light beam may be made parallel by the refractive power of both surfaces. That is, the refractive power at the collimating lens 21b may be dispersed between the light incident surface IS and the light exit surface ES.

  As described above, in the illuminating device 10 of the present embodiment, with respect to the reflection surface RF of the concave mirror 22b, the cross-sectional shape of the horizontal cross-section HS draws a parabolic arc, so that the light beam becomes parallel light with respect to the XZ plane. be able to. Furthermore, since the vertical cross section PS has an elliptical arc shape, the light beam can be converged with respect to the YZ plane. In addition to the sections HS and PS, the shape obtained by projecting the light beam on the XZ plane including the system optical axis SA becomes parallel light, and the shape obtained by projecting the light beam on the YZ surface including the system optical axis SA becomes convergent light. Designed to. At this time, the vertical direction, that is, the Y direction has an elliptical shape that tends to have relatively high light utilization efficiency, and therefore, both ends are cut to obtain the thickness dimension D of the concave mirror 22b (FIGS. 2B and 3B). )) Can be shortened. Thereby, the light source lamp unit 20 and the illuminating device 10 can be easily thinned. Further, in the horizontal direction, that is, in the X direction, since the light beam is collimated, the width of the light beam can be kept constant. Therefore, the illumination device 10 can adjust the aspect ratio of the cross-sectional shape of the light beam only by adjusting the elliptical arc, etc., and optical design can be performed relatively easily in making the device thin as described above. . Further, since the light beams are parallelized in the horizontal direction, that is, in the X direction, the parallelizing lens 21b in the subsequent stage can be formed into a cylindrical shape as described above, and thus can be easily manufactured and relatively inexpensive. .

  Hereinafter, the configuration and operation of the entire projector 100 will be described with reference to FIG. The color separation light guide 40 located on the downstream side of the optical path of the illumination device 10 includes first and second dichroic mirrors 41a, 41b, reflection mirrors 42a, 42b, 42c, three field lenses 43a, 43b, 43c, Relay lenses 44a and 44b, and separates the illumination light emitted from the illumination device 10 into three colors of red (R), green (G), and blue (B), and separates each color light in the subsequent stage. Guide to the liquid crystal light valves 50a, 50b, 50c. More specifically, first, the first dichroic mirror 41a reflects the R illumination light LR out of the three RGB colors and transmits the G and B illumination lights LG and LB. The second dichroic mirror 41b reflects the G illumination light LG of the two colors GB and transmits the B illumination light LB. That is, the red light LR reflected by the first dichroic mirror 41a is guided to the red optical path OP1 with the field lens 43a, and the green light LG transmitted through the first dichroic mirror 41a and reflected by the second dichroic mirror 41b is The blue light LB guided to the green light path OP2 having the field lens 43b and passing through the second dichroic mirror 41b is guided to the blue light path OP3 having the field lens 43c. The field lenses 43a, 43b, and 43c for the respective colors allow the partial light beams that are emitted from the second lens array 32, pass through the superimposing lens 35, and enter the light modulation unit 50 to be covered by the liquid crystal light valves 50a, 50b, and 50c. On the irradiation area, the incident angle is adjusted so as to have an appropriate convergence or divergence with respect to the system optical axis SA.

  The light modulation unit 50 includes three liquid crystal light valves 50a, 50b, and 50c into which the three colors of illumination lights LR, LG, and LB are respectively incident. Each of the liquid crystal light valves 50a, 50b, and 50c includes a liquid crystal panel 51a, 51b, and 51c disposed in the center, an incident-side polarization filter 52a, 52b, and 52c disposed on the upstream side of the optical path, and a downstream of the optical path. Side exit side polarization filters 53a, 53b, and 53c, respectively. Each color light LR, LG, LB incident on each of the liquid crystal light valves 50a, 50b, 50c is a pixel unit in accordance with a drive signal or a control signal input as an electrical signal to each of the liquid crystal light valves 50a, 50b, 50c. The intensity is modulated with. Each of the liquid crystal panels 51a, 51b, and 51c is a transmissive liquid crystal panel, and a description thereof is omitted. However, a light transmissive incident side substrate having a transparent electrode or the like, and a light having a pixel electrode or the like. A transparent driving substrate; and a liquid crystal layer hermetically sealed between the incident side substrate and the driving substrate.

  The color synthesizing unit 60 is a cross dichroic prism for synthesizing a color image, and includes a first dichroic film 61 for reflecting R light and a second dichroic film 62 for reflecting B light in a plane. It is arranged in a visual X shape. The color composition unit 60 reflects the red light LR from the liquid crystal light valve 50a by the first dichroic film 61 and emits the green light LG from the liquid crystal light valve 50b to the dichroic films 61 and 62. The blue light LB from the liquid crystal light valve 50c is reflected by the second dichroic film 62 and emitted to the left in the traveling direction.

  The projection optical system 70 projects the image light combined by the color combining unit 60 as a projection lens as a color image on a screen (not shown).

  The projector 100 according to the present embodiment has a reflecting surface RF having a horizontal section HS of a parabolic shape and a vertical section PS of an elliptical shape, and can be reduced in thickness while ensuring the parallelism of illumination light. By using this, the overall thickness can be reduced. That is, as described above, the illumination device 10 can easily reduce the thickness of the concave mirror 22b in the Y direction corresponding to the vertical direction, so that the projector 100 as a whole can be thinned in the Y direction.

[Second Embodiment]
Hereinafter, with reference to FIG. 8 (A) and 8 (B), the illuminating device etc. which concern on 2nd Embodiment of this invention are demonstrated. The illumination device according to the present embodiment is a modification of the illumination device 10 shown in FIG. 1 and is the same except for the structure of the secondary mirror. Unless otherwise explained, it has the same function as in the case of the lighting device 10, and illustration and description thereof will be omitted.

  As shown in FIGS. 8A and 8B, in the illumination device 110 according to the present embodiment, the secondary mirror 123a extends from the + Z direction to the + X direction on the side surface around the Y axis of the tube portion PB. A first portion 28a covering the region and a second portion 28b covering the region from the + Z direction to the -X direction among the side surfaces, and each portion 28a, 28b has a spherical reflection surface RR on the inside. Yes. The first portion 28a is disposed so as to face the -X side reflection surface RFa of the horizontal section HS and the surrounding reflection surface with the tube portion PB interposed therebetween, and the second portion 28b has the tube portion PB interposed therebetween. In the horizontal cross section HS, the reflective surface RFa on the + X side and the reflective surface in the vicinity thereof are arranged. As a result, the secondary mirror 123a does not cover the tube portion PB from the + Z direction to the ± Y direction, and a region corresponding to the reflecting surface RFb of the vertical section PS and the surrounding reflecting surface is substantially formed. There will be no. That is, the secondary mirror 123a has a reflecting surface that is wider in a region corresponding to the XZ plane including the system optical axis SA than in a region corresponding to the YZ plane including the system optical axis SA. As a result, the secondary mirror 123a prioritizes the light use efficiency on the reflection surface RFa of the horizontal section HS and the surrounding reflection surface over the light use efficiency on the reflection surface RFb of the vertical section PS and the surrounding reflection surface. It is something that enhances. In the reflecting surface RFa side of the horizontal section HS that draws a parabolic arc, the light uptake rate tends to be relatively lower than the reflecting surface RFb side of the vertical section PS that draws an elliptical arc. Further, the reflection of the secondary mirror 123a is increased to improve the uniformity of the illumination light.

  Note that the illumination device 110 can be assembled to the projector 100 in the same manner as the illumination device 10. Since the illumination device 110 can be thinned similarly to the illumination device 10, the projector 100 in which the illumination device 110 is assembled can also be thinned.

[Third Embodiment]
Hereinafter, with reference to FIG. 9 (A) and 9 (B), the illuminating device etc. which concern on 3rd Embodiment of this invention are demonstrated. The illumination device according to the present embodiment is a modification of the illumination device 10 shown in FIG. 1 and is the same except for the structure of the secondary mirror. Therefore, only the lamp portion of the illumination device is illustrated and other optical elements are illustrated. Unless otherwise specified, it is assumed that the lighting device 10 has the same function as that of the lighting device 10, and illustration and description thereof are omitted.

  As shown in FIGS. 9A and 9B, in the illumination device 210 according to the present embodiment, the secondary mirror 223a directly coats a part of the bulb portion PB that is a light transmission portion of the arc tube 22a. It is formed by. That is, the secondary mirror 223a is formed by forming a reflection surface by vapor deposition of a dielectric multilayer film or the like on approximately half of the surface of the tube portion PB opposite to the concave mirror 22b. In this case, the secondary mirror 123a can be manufactured relatively easily.

  Further, as another example, as in the lighting device 310 shown in FIGS. 10A and 10B, a relatively large amount of light is taken in when the secondary mirror 323a is formed by directly coating a part of the tube portion PB. You may coat corresponding to reflective surface RFa of horizontal section HS which draws a parabolic arc with a low rate, and the reflective surface of the circumference. That is, as in the case of FIGS. 8A and 8B, the secondary mirror 323a is formed so as to face the reflective surface RFa and the surrounding reflective surface, thereby forming a parabolic shape. It is good also as what can improve the utilization efficiency of the light in a surface preferentially.

  The lighting devices 210 and 310 can be assembled to the projector 100 in the same manner as the lighting device 10. Since the illumination devices 210 and 310 can be thinned similarly to the illumination device 10 and the like, the projector 100 in which the illumination devices 210 and 310 are assembled can also be thinned.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments.

  First, in the case of this embodiment, a light beam having an extremely flat light beam cross section FF, that is, a sheet light beam can be relatively easily produced. For example, the sheet light beam can have an aspect ratio of 1: 3 (or higher). It is.

  In each of the above embodiments, the secondary mirror is used, but a configuration without the secondary mirror is also possible. In this case, it is desirable to make the reflecting surface RFa large in the horizontal direction. Note that even if the reflecting surface RFa is large in the horizontal direction, it does not directly affect the thinning of the device, so that the thinning of the lighting device and the projector is not hindered.

  In each of the above embodiments, the horizontal section HS has a parabolic shape and the vertical section PS has an elliptical shape. Conversely, the horizontal section HS has an elliptical shape, and the vertical section PS has a vertical shape. May be parabolic. For example, for a vertical projector, the horizontal section HS can be made elliptical, and the vertical section PS can be made parabolic.

  In addition, the projector 100 illustrated in the first embodiment has a configuration using a pair of lens arrays 31 and 32 as an integrator optical system. However, the illumination device according to the present invention is also a projector using a rod integrator. In the same manner, the entire projector can be reduced in thickness.

  In the above embodiment, an example in which the present invention is applied to a projector including the transmissive liquid crystal light valves 50a, 50b, and 50c has been described. However, the present invention also applies to a projector including a reflective liquid crystal light valve. It is possible to apply. Here, “transmission type” means that the liquid crystal light valve is a type that transmits light, and “reflection type” means that the liquid crystal light valve is a type that reflects light. ing.

  Moreover, as a projector, there are a front projection type projector that projects an image from the direction of observing the projection surface and a rear projection type projector that projects an image from the side opposite to the direction of observing the projection surface. The configuration of the projector shown in 1 etc. can be applied to any of them.

  DESCRIPTION OF SYMBOLS 10,110,210,310 ... Illuminating device 20 ... Light source lamp unit 21a ... Lamp part 21b ... Parallelizing lens 22a ... Arc tube, 22b ... Concave mirror, RF, RFa, RFb, RFc ... Reflective surface, 23a ... Sub-mirror, 30 ... homogenizing optical system, 40 ... color separation light guide unit, 50 ... light modulation unit, 50a, 50b, 50c ... liquid crystal light valve, 51a, 51b, 51c ... liquid crystal panel, 60 ... color composition unit, 70 ... Projection optical system, 100 ... Projector, HS ... Horizontal section, PS ... Vertical section, SA ... System optical axis

Claims (11)

An arc tube for generating light;
Of the shapes cut by two planes perpendicular to each other including the system optical axis, the shape cut by one plane draws a parabolic arc focusing on the center between the electrodes of the arc tube and the other plane. A reflecting surface having a non-rotationally symmetric shape that draws an elliptical arc whose first focal point is the focal point of the parabolic arc, and reflects light from the arc tube on the reflecting surface. An anamorphic reflector that emits illumination light;
A lighting device comprising:   The lighting device according to claim 1, wherein the non-rotationally symmetric shape of the reflecting surface is a continuous curved surface shape that gradually changes from a parabolic shape to an elliptical shape from the one plane toward the other plane.   3. The apparatus according to claim 1, further comprising a collimating lens that is disposed on the downstream side of the optical path of the arc tube and the anamorphic reflector and that collimates light passing therethrough by having a cylindrical aspheric surface. The lighting device according to item.   4. The illumination device according to claim 3, wherein in the collimating lens, the cylindrical aspherical generatrix extends in a direction parallel to a plane perpendicular to the system optical axis and parallel to the one plane.   5. The illumination device according to claim 3, wherein the collimating lens has a hyperboloid on the light incident side as the cylindrical aspheric surface. 6.   The illuminating device according to any one of claims 3 to 5, wherein the collimating lens has a flat surface or a cylindrical spherical surface on a light emission side.   The said arc tube has any auxiliary reflector which reflects the light inject | emitted in the reverse direction from the center between the electrodes of the said arc tube on the opposite side to the said anamorphic-type reflector. The lighting device according to claim 1.   The lighting device according to claim 7, wherein the auxiliary reflecting mirror has a reflecting surface that is wider in a region corresponding to the one plane than in a region corresponding to the other plane.   The projector according to any one of claims 7 and 8, wherein the auxiliary reflecting mirror is formed by directly coating a part of a light transmission portion of the arc tube. An arc tube for generating light;
Of the two planes perpendicular to each other including the system optical axis, the luminous flux from the arc tube is reflected as parallel light when viewed from the direction perpendicular to one plane, and viewed from the direction perpendicular to the other plane. A reflecting mirror having a reflecting surface for reflecting the luminous flux from the arc tube as convergent light;
A lighting device comprising: The lighting device according to any one of claims 1 to 10,
A light modulation device illuminated by a light beam emitted from the illumination device;
A projection optical system for projecting a light beam emitted from the light modulation device;
A projector comprising:

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