JP5311880B2 - Light source device and image display device using the same - Google Patents

Description

  The present invention relates to a light source device. In particular, the present invention relates to a light source device used for a projector or the like.

  In recent years, when a presentation or the like is performed, an opportunity to use a projector that enlarges and projects an image on a screen or the like is increasing.

  The light source device used for this projector is required to have high brightness and downsizing, and methods described in Patent Documents 1, 2, and 3 have been proposed to meet such demands.

  The light source devices of Patent Documents 1 and 2 are provided with an elliptical reflector on the upper side of the light emitting part, and a spherical reflector centered on the light emitting part of the lamp on the lower side, and a light beam that is output downward from the light emitting part Is output to the elliptical reflector through the light emitting unit.

The light source device of Patent Document 3 is intended to increase the brightness, and has a lamp core portion (glass tube) that includes a light emitting portion, and a semi-elliptical surface that reflects light emitted from the light emitting portion toward a subsequent optical system. doing. Here, the reflective layer is directly provided in the area | region on the opposite side to a semi-elliptical surface among the surfaces of a lamp core part. By comprising in this way, the light beam output toward the opposite side of the semi-elliptical surface can be reflected by the reflective layer and guided to the semi-elliptical surface.
JP 2001-109068 A (paragraph 0008, FIG. 1) Japanese Patent Laying-Open No. 2003-059303 (paragraph 0014, FIG. 1) JP 2006-253120 A (paragraph 0013, FIG. 3)

  As described in the above-mentioned patent documents, when the luminous flux emitted from the light emitting part is returned to the light emitting part or its vicinity again and the luminous intensity is increased by using those luminous fluxes, the glass tube covering the light emitting part is used. Optical characteristics greatly affect brightness.

  However, since Patent Documents 1 and 2 only provide a spherical reflecting surface centered on the light emitting part, the light returned to the light emitting part cannot be used efficiently. In addition, Patent Document 3 merely provides a reflection layer directly on the surface of the glass tube for miniaturization, and the light returning to the light emitting part is affected by the optical characteristics of the glass tube. Light cannot be used efficiently.

  Therefore, an object of the present invention is to provide a light source device capable of obtaining the effects of downsizing and high brightness in consideration of the optical characteristics of the glass tube.

In order to solve the above problems, in the light source device of the present invention, a first lamp that includes a pair of electrodes and a glass tube that covers a discharge space between the pair of electrodes, and emits light by discharge between the pair of electrodes; When the direction connecting the pair of electrodes is the X axis, the first lamp is disposed on one side across the X axis and reflects light emitted from the first lamp in a direction different from that of the first lamp. A light source device including a reflector and a first reflection surface disposed on the other side across the X axis and guiding light emitted from the first lamp to the first reflector via the first lamp; The first reflecting surface is a toric surface, and the shape in the first plane with the X axis as a normal is a circle,
The radius of curvature in the first plane is smaller than the radius of curvature in the second plane that is perpendicular to the first plane and includes the X axis, and the thickness of the glass tube in the second plane becomes thinner toward both ends. In the case where the curvature radius in the second plane is an aspherical shape that increases toward both ends, and the thickness of the glass tube in the second plane increases toward both ends, the second It is characterized by an aspherical shape in which the radius of curvature in the plane decreases toward both ends .

  According to the present invention, it is possible to provide a light source device that is small and has high light utilization efficiency.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  A light source device according to a first embodiment of the present invention will be described with reference to FIG.

  The light source device 1 of the present embodiment includes a light source lamp (lamp, first lamp, light source that emits light by discharge) 2, a reflector (first reflector) 5, and a sub-reflecting mirror (first reflecting surface) 6.

  In the present embodiment, the light source lamp 2 has a pair of electrodes 3 and a glass tube (a light emitting tube, a lamp tube) 4, and the glass tube 4 includes a pair of electrodes 3 and a high-pressure (pressure). A gas such as mercury or a rare gas is enclosed. Specifically, the light source lamp 2 is a metal halide lamp, a high-pressure mercury lamp, or the like. Here, a direction connecting the pair of electrodes 3 is defined as an X direction (X axis), and a direction orthogonal thereto is defined as a Y direction (Y axis). FIG. 1 is a cross-sectional view in a plane (XY cross section including X axis and Y axis, second plane) parallel to both the X direction (X axis) and the Y direction (Y axis).

  The reflecting surface of the reflector 5 is a parabolic mirror or an elliptical mirror (based on an aspherical surface) having a focal point (one of the focal points) between the pair of electrodes 3. This reflection surface is a (aspheric) reflection surface having a rotationally symmetric shape with the X direction (X axis) as a rotational symmetry axis. The reflector 5 does not actually have a rotationally symmetric shape, but has a shape in which substantially half of the rotationally symmetric shape is cut out. (Reflection surface) 6 is arranged.

  In such a configuration, the light source lamp 2 causes a discharge phenomenon when a high voltage is applied between the pair of electrodes 3, and forms a light source arc (light emitting point, light emitting region, discharge space, discharge region) between the electrodes. Light emitted from the light source arc is emitted toward the surroundings. Light emitted from the light source arc travels through the glass tube 4 to the reflector 5 and the sub-reflecting mirror 6. Since the light source arc is arranged in the vicinity of the focal point of the reflector 5, the light beam (normal optical path) directed toward the reflector 5 is reflected by the reflector 5, and an optical system (not shown) in the rear stage (in the X direction in the upper part of FIG. 1). ). At this time, if the reflecting surface of the reflector 5 is a paraboloid, it is emitted from the reflector 5 as substantially parallel light, and if it is an elliptical surface, it is emitted as convergent light. On the other hand, of the light beams that have passed through the glass tube 4, the light beam (recursive light path) directed to the sub-reflecting mirror 6 is reflected by the reflecting surface 7 and forms an image of the light source arc near the light source position. Light from the image of the light source arc enters the reflector 5, is reflected by the reflector 5 in the same manner as the light described above, and is guided to the subsequent optical system as parallel light or convergent light. However, if the imaging performance of the light source arc image is poor (it is very large compared to the original light source arc, or the image is formed at a position different from the original light source arc), the light from the light source arc image is optically downstream. It is vignetting in the system, and can not contribute much to high brightness.

  This is due to the following reasons. When the light source arc is an ideal point and the inner wall and the outer wall of the glass tube 4 have an ideal spherical surface (sphere) centered on the point of the light source arc, the reflecting surface 7 of the sub-reflector is used. If it is also spherical, the image of the light source arc also becomes a point, which contributes to higher brightness. However, the light source arc is not an ideal point light source. Furthermore, the inner wall and the outer wall of the glass tube 4 often have different non-spherical shapes for manufacturing reasons. In particular, for manufacturing reasons, the glass tube shape is substantially circular in the section A (first plane) having the X axis as a normal, but is aspherical in the section B (second plane) including the X axis. In many cases, the cross section A and the cross section B have different curvatures. That is, the glass tube has a so-called toric shape (toric surface) in which the radius of curvature is different between the cross-section A and the cross-section B (the shape of the reflecting surface is different). Since the light is refracted, the imaging performance of the image of the light source arc in the cross section B is deteriorated. In particular, since the light path reflected by the sub-reflecting mirror passes through the glass tube twice, the influence of refraction by the glass tube becomes very large.

  In the prior art, each of the sub-reflecting mirrors is a simple spherical mirror with the light source (light source arc) position as the center of the sphere. It will collapse. FIG. 7 shows a light beam simulation result using a spherical mirror and a toric glass tube using a conventional technique, a light source arc intensity distribution (light intensity distribution in a light emitting region), and a re-imaging arc intensity distribution according to the conventional technique. It can be seen that the re-imaging arc is larger than the original light source arc, and its intensity distribution is significantly different from that of the original light source arc. As a result, much of the light reflected by the sub-reflecting mirror is reflected or scattered by the electrode 3 or is vignetted (lost) by the subsequent optical system (illumination optical system). The utilization efficiency of was hardly improved.

  Therefore, the sub-reflecting mirror 6 of the present embodiment has a toric concave reflecting surface 7 disposed so as to face the reflector 5 with the light source lamp 2 interposed therebetween. The reflection surface 7 has a substantially circular shape in a cross section A (cross section A in FIG. 1) whose normal direction is the X direction, and a cross section in an XY cross section (paper surface in FIG. 1) orthogonal thereto. The shape is different from the shape in A. Specifically, in the XY cross section, a circle having a different curvature from the circle in the cross section A (or an aspheric surface based thereon) or an aspheric surface based on a circle having the same curvature as the circle in the cross section A is formed. In the present invention, these are called toric surfaces. Here, the shape of the reflecting surface 7 of the sub-reflecting mirror in the XY cross section (that is, the plane including the X-axis connecting both electrodes and the direction in which the reflecting mirror and the sub-reflecting mirror are arranged) has a curvature as it goes to both ends in the X-axis direction. It is desirable that the aspherical shape has a shape in which the radius is increased (curvature is reduced). The shape of the reflecting surface 7 is a suitable shape according to the change in the thickness of the glass tube. In this embodiment, since it is assumed that the thickness of the glass tube becomes thinner toward the periphery, the radius of curvature of the reflecting surface 7 is configured to become larger (relaxed) toward the periphery. On the other hand, when the thickness of the glass tube increases toward the peripheral portion, it is desirable that the radius of curvature of the reflecting surface 7 be made smaller (tighter) toward the peripheral portion.

  As described above, the reflecting surface 7 has different shapes for the cross section A and the cross section B, and has a toric surface shape with the X axis as a rotationally symmetric axis. Considering the influence of refraction (occurrence of aberration) caused by passing the glass tube 4 twice in a reciprocating manner, the shape of the reflecting surface 7 in the cross section B reduces the above-described influence of refraction (reduces and corrects aberration). Shape. In other words, the shape of the reflecting surface 7 of the sub-reflecting mirror is such that the light transmitted through the glass tube 4 is returned to the light source arc (light emitting point), that is, an aberration generated in the glass tube 4 (having the glass tube). The shape is such that light emitted from the glass tube 4 is returned to the light source arc while reducing (local power). Specifically, the reflecting surface 7 is configured so that light transmitted through the glass tube 4 can pass through a plane including the arrangement direction of the light source lamp and the sub-reflecting surface (or a reflector) and the optical axis direction of the illumination optical system. Any shape that is incident at an incident angle of substantially 90 degrees (85 degrees or more, preferably 88 degrees or more) may be used. In other words, the reflecting surface 7 moves from the central portion toward the peripheral portion in a plane including the arrangement direction of the light source lamps and the sub-reflecting surface (may be a reflector) and the optical axis direction of the illumination optical system. As long as the radius of curvature becomes large (curvature becomes gentle), it is sufficient.

  FIG. 2 shows a ray diagram and a re-imaging arc intensity distribution when the toric reflecting surface 7 of this embodiment is used as a sub-reflecting mirror. Compared with the conventional re-imaging arc shape shown in FIG. 7, the re-imaging arc image having almost the same intensity distribution as the original light source arc intensity distribution is formed (the image of the light source arc with almost no aberration). Is connected).

  As described above, according to this embodiment, an image of a re-imaging arc having the same intensity distribution as that of the light source arc can be formed in the vicinity of the light source arc. As a result, the light from the image of the re-imaging arc is guided to the subsequent optical system with the same efficiency (illumination efficiency) as the light from the original light source arc, so that the light utilization efficiency can be improved. It leads to high brightness.

  In the present embodiment, the reflecting surface 7 is a toric surface with the X axis as a rotational symmetry axis, but it is not necessarily required to be rotationally symmetric and may have a non-rotationally symmetric shape from the viewpoint of aberration correction.

  An illumination optical system according to the second embodiment of the present invention will be described with reference to FIG.

  The illumination optical system of this embodiment is obtained by applying the light source device 1 of the first embodiment to a projector using a reflective liquid crystal panel. Although this embodiment has a single-panel projector configuration for simplicity, it can be similarly applied to a projector including a color separation / synthesis system using a plurality of liquid crystal panels for each primary color. The present invention can also be applied to an illumination optical system using a transmissive liquid crystal panel.

  The light beam emitted from the light source device 1 is a reflective liquid crystal panel (image display element, image forming element, liquid crystal panel, light) which is a surface to be illuminated by the first fly-eye lens 8, the second fly-eye lens 9, and the condenser lens 11. The modulation element 13 is illuminated. A polarization conversion element 10 is disposed between the second fly-eye lens 9 and the condenser lens 11, whereby a non-polarized light beam after exiting the light source device 1 is converted into p-polarized light (a straight line that vibrates in the paper surface). Polarized light, of course, s-polarized light). A polarizing beam splitter (PBS) 12 is disposed between the condenser lens 11 and the reflective liquid crystal panel 13. Of the light modulated by the reflective liquid crystal panel 13, the image light becomes s-polarized light and is reflected by the polarizing beam splitter 12, and the unwanted light passes through the polarizing beam splitter 12 while remaining p-polarized light toward the projection lens 14 side. 11 side. Finally, the image light is imaged on a screen (projected surface, not shown) by the projection lens 14, and an image is displayed on the screen.

  The advantage of this embodiment over the conventional illumination optical system is that both brightness and contrast can be achieved. The polarization beam splitter has an angular sensitivity (of the p-polarized reflection characteristic) in the cross-section (incident surface, in the plane of FIG. 3) including the normal of the polarization separation surface and the incident light direction (optical axis of the illumination optical system). High, greatly affects the overall contrast performance of the projector (image contrast on the screen). In other words, in an illumination optical system using a reflective liquid crystal panel and a polarizing beam splitter, the narrower the angular distribution in the direction of the incident surface (including the normal of the polarization separation surface of PBS and the optical axis of the illumination optical system), the more the contrast It becomes easy to raise. In the conventional illumination optical system, the angle width in the incident surface direction (incident angle) is obtained by cutting the light in the incident surface direction with a diaphragm or by arranging an afocal system that compresses the light beam in the incident surface direction after exiting the light source device. The width of the incident angle of light) was reduced. In such a conventional technique, light is lost and the number of parts increases, and as a result, even if the contrast is increased, it is avoided that the brightness is reduced and the assembly is troublesome. I couldn't.

  However, in the present embodiment, the above-described method is not used, and the light beam emitted from the light source device 1 has a narrow cross section (in the plane of FIG. 3, the direction in which the reflector and the sub-reflecting mirror 6a are arranged) And the plane defined by the optical axis of the illumination optical system are matched (parallel). As a result, the angle distribution in the direction of the incident surface of the polarizing beam splitter 12 can be narrowed, so that the contrast can be improved. That is, according to the present embodiment, both brightness and contrast can be achieved.

  This concept can be applied to all elements using not only a polarizing beam splitter but also a high angle sensitivity characteristic. That is, compared with the prior art, the light beam exit of the light source device 1 of the present invention is approximately halved in one direction, so that the angular distribution in one direction can be halved even though the light amount is the same. Therefore, by matching this cross section with a cross section having high sensitivity of the angle characteristics of the optical element, it is possible to greatly improve the performance of the projector as compared with the prior art. For example, when applied to a dichroic mirror, performance such as color unevenness can be improved.

  Here, the light source device 1 (the direction connecting the pair of electrodes and the arrangement direction of the lamp tube 4 and the sub-reflecting mirror 6a) and the direction of the polarization separation surface of the polarization beam splitter 12 are in the positional relationship of FIG. There are the following reasons. Due to the film characteristics of the polarizing beam splitter, the polarization separation performance of p-polarized light (transmission characteristics of p-polarized light) improves as the incident angle on the film becomes larger than 45 °. The intensity gravity center of the light beam emitted from the light source device 1 is on the light source lamp side. In view of these, the positional relationship of FIG. 3 makes it possible for more light to be incident on the polarization separation surface on the side with high polarization separation performance (side with a large incident angle), so that the contrast can be further increased. That is, of the light reflected by the reflector 5 of the light source device 1, the incident angle of the light reflected at a position far from the light source lamp 2 (electrode 3) to the polarization separation surface is close to that of the light source lamp 2 (electrode 3). It is preferable to arrange the light reflected at the position to be smaller than the incident angle to the polarization separation surface. In other words, the plane (third plane) defined by the optical axis of the illumination optical system and the normal of the polarization separation surface of the polarization beam splitter is the X axis (the arrangement direction of both electrodes, the optical axis of the illumination optical system). ) In parallel.

  This embodiment relates to a so-called two-lamp type projector using two light source devices (lamps) according to the first embodiment (a method using two lamps of a first lamp and a second lamp). Here, the light from the first lamp is reflected by the first reflector (first main reflecting mirror), the light from the second lamp is reflected by the second reflector (second main reflecting mirror), and these two reflectors are reflected. Are synthesized by using an optical path synthesis element 15 described later. Although this embodiment will be described in detail with reference to FIG. 4, the points not particularly described are the same as those of the second embodiment.

  The light beams emitted from the respective light source devices 1 are deflected in the same direction (the left side in FIG. 4, that is, the direction along the optical axis of the condenser lens of the illumination optical system) by the optical path synthesis element 15. In this embodiment, the optical path is synthesized by an element having a mirror vapor deposition (reflection film vapor deposition) on the prism. Of course, the optical path synthesis method is not limited to this, and can be realized by various methods such as an afocal system using a convex / concave lens, a triangular prism, and a concave lens. It can also be realized by combining the optical paths by bending only the light emitted from one light source device (without bending the light emitted from the other light source device).

  Here, the light beam combined in the optical path is guided to the liquid crystal panel surface as in the second embodiment. The difference from the second embodiment is the relationship between the polarization separation surface of the polarization beam splitter and the direction of the light source device 1. In Example 3, a plane (longitudinal section in FIG. 4) including the normal line of the incident surface of the polarization separation surface and the optical axis of the illumination optical system (the optical axis of the condenser lens or the normal line of the illuminated surface). Is orthogonal to the direction in which the width of the emitted light beam of the light source device 1 is narrow (the horizontal direction in FIG. 4, the direction in which the reflector and the sub-reflecting mirror 6b are arranged). In addition, the description to the effect of orthogonality mentioned here is a description about the case where the optical path of an illumination optical system is developed. In other words, in other words, the above-described content is such that the plane including the normal line of the incident surface of the polarization splitting surface and the optical axis of the illumination optical system has a direction in which the width of the light beam emitted from the light source device is narrow (transverse in FIG. 4). It can also be said that the horizontal direction of the surface view is orthogonal to the direction bent by the optical path combining element 15 (the vertical direction of the cross-sectional view of FIG. 4).

  This is because, since two light source devices (lamps) are arranged in parallel in the cross section of FIG. 4, the light flux width in the cross section (parallel direction) becomes relatively wide (contrast decreases). In addition, the vertical cross section with a narrow beam width, the normal line of the polarization separation plane, and the plane formed by the optical axis are parallel.

  That is, the direction in which the first lamp and the second lamp are arranged is defined as the arrangement direction (the vertical direction in the cross-sectional view in FIG. 4 and the direction perpendicular to the paper surface in the vertical cross-sectional view in FIG. 4). At this time, it is desirable that the plane (third plane) defined by the optical axis of the illumination optical system and the normal line of the polarization separation plane of the polarization beam splitter is perpendicular to the arrangement direction. With this configuration, highly efficient illumination can be performed in the two-lamp illumination optical system using the first lamp, the second lamp, the first reflector, the second reflector, and the optical path synthesis element.

  According to the configuration of the third embodiment described above, the illumination efficiency can be significantly increased as compared with the conventional two-lamp type. In the conventional two-lamp type, the light source devices are arranged in parallel as they are and the overall size of the light source device becomes large. Therefore, the focal length of the illumination optical system is extended, and as a result, the illumination efficiency is greatly reduced. On the other hand, the illumination optical system of the third embodiment can arrange two light source devices so as to have almost the same size as one conventional light source device. It can be as high as one-lamp type). Furthermore, by using the optical path synthesis method of the present embodiment, the two light source devices do not physically interfere with each other, and the interval between the two light source devices is reduced in a pseudo manner, so that the illumination efficiency is easily increased.

  A fourth embodiment of the present invention will be described in detail with reference to FIG. The points not particularly described are the same as those in the third embodiment.

  The light source device 17 according to the present embodiment has a configuration in which two light source devices described in the first embodiment are arranged adjacent to each other (in the opposite direction) in parallel. The sub-reflecting mirror disposed between the two light source devices is a double-sided reflecting mirror (a member having a first reflecting surface and a second reflecting surface facing in opposite directions) 16. The two reflecting surfaces are toric surfaces (reflecting surfaces having a toric surface shape). In this way, the number of parts can be reduced by providing a configuration in which the second reflecting surface is provided on the back side of the first reflecting surface (two reflecting surfaces facing in opposite directions are provided on one member). In addition, space saving and cost reduction can be realized.

  Except for the points described above, the third embodiment is the same as the third embodiment. FIG. 6 shows the arrangement of an illumination optical system using the light source device 17. Here, as in the third embodiment, a plane (in FIG. 6) includes the normal line of the incident surface of the polarization separation surface and the optical axis of the illumination optical system (the optical axis of the condenser lens or the normal line of the illuminated surface). The vertical cross section is orthogonal to the cross section of the light source device 1 where the width of the emitted light beam is narrow (the cross section in FIG. 6, the direction in which the reflector and the sub-reflecting mirror are arranged).

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist. In these drawings, only basic components of the projector optical system are drawn for ease of explanation, but other configurations such as an optical path folding mirror, a heat ray cut filter, a polarizing plate, etc. The same applies to systems using a plurality of liquid crystal panels. Further, the present invention can be applied to a projector using other display elements such as a transmissive liquid crystal panel and a micromirror device.

1 is a configuration diagram of a light source device according to a first embodiment of the present invention. Explanatory drawing of light source re-imaging by the toric reflector of the present invention Configuration diagram of illumination optical system according to second embodiment of the present invention FIG. 6 is a configuration diagram of an illumination optical system that is a third embodiment of the present invention. Block diagram of a light source device used in the fourth embodiment of the present invention FIG. 6 is a configuration diagram of an illumination optical system that is a fourth embodiment of the present invention. Explanatory drawing of light source re-imaging by conventional technology

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source device 2 Light source lamp 3 Electrode 4 Glass tube 5 Reflector 6 Subreflective mirror 7 Toric mirror surface 8 1st fly eye lens 9 2nd fly eye lens 10 Polarization conversion element 11 Condenser lens 12 Polarization beam splitter 13 Reflection type liquid crystal panel DESCRIPTION OF SYMBOLS 14 Projection lens 15 Optical path composition element 16 Biconcave reflection mirror 17 Light source device 18 Spherical mirror

Claims (8)

A first lamp that includes a pair of electrodes and a glass tube that covers a discharge space between the pair of electrodes, and emits light by discharge between the pair of electrodes;
When the direction connecting the pair of electrodes is the X axis,
A first reflector disposed on one side across the X axis and reflecting light emitted from the first lamp in a direction different from the first lamp;
A light source device having a first reflecting surface arranged on the other side across the X axis and guiding light emitted from the first lamp to the first reflector via the first lamp;
The first reflecting surface,
Toric surface Der is,
The shape in the first plane with the X axis as a normal is a circle,
A radius of curvature in the first plane is smaller than a radius of curvature in a second plane perpendicular to the first plane and including the X axis;
When the thickness of the glass tube in the second plane becomes thinner toward both ends, the radius of curvature in the second plane is an aspherical shape that increases toward the both ends,
The light source device according to claim 1, wherein when the thickness of the glass tube in the second plane increases toward both ends, the light source device has an aspherical shape such that the radius of curvature in the second plane decreases toward the both ends. A second lamp that includes a pair of electrodes and a glass tube that covers a discharge space between the pair of electrodes, and emits light by discharge between the pair of electrodes;
A second reflector that reflects light emitted from the second lamp in a direction different from that of the second lamp;
2. The light source device according to claim 1 , further comprising: an optical path combining element that combines light reflected by the first reflector of the first lamp and light reflected by the second reflector of the second lamp. A second lamp that includes a pair of electrodes and a glass tube that covers a discharge space between the pair of electrodes, and emits light by discharge between the pair of electrodes;
A second reflector that reflects light emitted from the second lamp in a direction different from that of the second lamp;
A second reflecting surface for guiding light emitted from the second lamp to the second reflector through the second lamp;
The light source device according to claim 1, characterized in that the member on which the first reflecting surface is formed, the second reflecting surface on the back side of the first reflecting surface is arranged. The light source device according to any one of claims 1 to 3 ,
An illumination device comprising an illumination optical system that guides light from the light source device to a surface to be illuminated through a polarization beam splitter. A light source device according to claim 1;
An illumination optical system that guides light from the light source device to an illuminated surface via a polarization beam splitter;
Having only one first lamp,
Lighting device before Symbol third plane parallel to the optical axis of the illumination optical system and the normal to the polarization separation surface of the polarization beam splitter, characterized in that it is parallel to the X axis. The light source device according to claim 2 or 3 ,
An illumination optical system that guides light from the light source device to an illuminated surface via a polarization beam splitter;
When the direction in which the first lamp and the second lamp are arranged is an arrangement direction,
An illumination device, wherein a third plane parallel to an optical axis of the illumination optical system and a normal line of a polarization separation surface of the polarization beam splitter is perpendicular to the arrangement direction. The illuminated surface is an image display element,
In order from the first lamp toward the image display element,
A first lens array;
A second lens array;
A polarization conversion element having a plurality of polarization separation surfaces arranged along a direction perpendicular to the optical axis of the illumination optical system, and aligning the polarization direction of incident light;
A condenser lens,
Having the polarization beam splitter;
The illumination device according to claim 5 or 6, wherein an arrangement direction of a plurality of polarization separation surfaces of the polarization conversion element is a direction perpendicular to the third plane. An image display element;
Illuminating the image display device, image display device, characterized in that it comprises a lighting device according to any one of claims 4 to 7.

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