JP2010140745A - Illuminating device and projection type image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device that efficiently uses a light beam emitted from a light source having an area.
When a light source that emits light, a light beam separating unit, a first condensing optical system, and a second condensing optical system are provided, and a normal passing through the light emitting surface center of the light source is an optical axis The light beam separating means is an optical element that transmits a light beam having a small angle with respect to the optical axis among light beams incident from the light source and totally reflects a light beam with a large angle with respect to the optical axis at least once, The first condensing optical system has a function of condensing the light beam that has passed through the light beam separating means at one point, and the second light collecting optical system is operated at least once by the light beam separating means. It has the effect | action which condenses the reflected light beam to one point.
[Selection] Figure 1

Description

  The present invention relates to an illumination optical system using a surface light source and a projection display device.

  In recent years, as a light source of an illuminating device, a solid light emitting element light source such as an LED or an organic EL, in particular, a surface emitting light source that emits light from a planar light emitting region is increasing. The amount of light emitted by these surface-emitting light sources has been remarkably improved, and it is also considered to use a surface-emitting light source for the light source device of the projection type image display device. In this case, it is necessary to consider not only the light emission efficiency of the light source but also the light use efficiency in the optical system including the spatial light modulator and the projection lens. In an optical system including a light source and a liquid crystal light valve, a spatial spread in which a light beam that can be effectively handled exists can be expressed as a product of an area and a solid angle (etendue). The etendue tends to be stored before and after transmission through the illumination optical system. In general, a spatial light modulator has a limited light capture angle that can be effectively modulated. Therefore, when illuminating this, it is necessary to illuminate with a light beam having a small solid angle. That is, it is desirable that the etendue on the spatial modulation device is small.

  However, the light emitted from the surface light source generally emits light with a large diffusion angle and has a large light emitting area, so that the etendue of the emitted light beam tends to increase. As described above, since the etendue is generally stored before and after the illumination optical system, when a surface emitting light source is used, the etendue on the spatial light modulation device to be illuminated becomes large. That is, the light that illuminates the spatial light modulation device has a larger solid angle of the light beam or an increased illumination area. In the former case, waste is generated with respect to the effective light taking-in angle characteristic of the spatial light modulator, and in the latter case, the light that protrudes from the effective display area of the spatial light modulator is increased, resulting in waste. However, it turns out that illumination efficiency falls.

  Therefore, improvement of illumination efficiency when a large area light source is used becomes a problem.

  A solution corresponding to this problem has been proposed.

  A method of collimating all the light from the surface light source at once is well known. Patent Document 1 proposes a method of parallelization using a meniscus lens and an aspheric lens. In addition, a method of parallelization using a concave mirror called CPC has been proposed as in Patent Document 2. The CPC concave mirror has a focus locus in a ring shape. In Patent Document 2, the end surface of the surface light source is matched. Thereby, all the points on the surface light source, in particular, the peripheral portion are approximated so that light is emitted from the focal point, and the light from the light source is made parallel. However, because of the etendue relationship, the size and parallelism of the light source device are a trade-off, so that if the directivity is improved, the beam diameter is increased accordingly. Conversely, if you try to make it smaller, the directivity will worsen. Therefore, it is difficult to improve the light utilization efficiency of the illumination system when a large area light source is used. Furthermore, in the method of Patent Document 2, the amount of positional deviation from the focal point becomes larger toward the center of the light source. For this reason, the larger the light source, the greater the amount of deviation from the focal point at the center and the worse the parallelism.

  As another method, there is an optical system that collimates light from a surface light source using a concave mirror and a lens simultaneously. (Patent Document 3) By distributing a light beam from a light source to two elements, etendue of a light beam incident on each optical system can be suppressed.

  In the configuration example of Patent Document 3, a concave mirror and a lens are used.

  The concave mirror is a parabolic mirror that takes in a light beam emitted at a large angle with respect to the normal of the surface light source, and is arranged so that the center point of the surface light source coincides with the focal point of the parabolic mirror. .

  On the other hand, the lens takes in a light beam emitted at a small angle with respect to the normal of the surface light source, and is arranged so that the focal point of the light collecting element coincides with the center of the surface light source. As described above, in Patent Document 3, the condensing optical system is changed in accordance with the divergence angle of the light beam emitted from the light source to suppress the etendue of the light beam incident on each optical system.

  However, in the above configuration example, the design is performed with the center of the surface light source as a reference, so that performance actually deteriorates. FIG. 18 is an explanatory diagram of this. Since the light emitted from the center of the surface light source 101 is emitted from the focal position of the condenser lens 102, it is parallel to the optical axis when entering the lens. At this time, light having an angle of θ1 or less with respect to the optical axis is incident on the condenser lens 102 from light emitted from the center of the surface light source 101. On the other hand, regarding the light emitted from the periphery of the light source, light having an angle formed with the optical axis having an angle θ2 larger than θ1 also enters the condenser lens 102. Thereby, the maximum value of the angle formed with the optical axis of the light incident on the condenser lens 102 is θ2 (> θ1). Therefore, the light beam cannot be parallel to the optical axis. In Patent Document 2, the light transmitted through the condenser lens has poor parallelism for the above reasons.

  A method of separating light emitted from a light source by a divergence angle using a refractive optical system has been proposed. (Patent Document 4) The refractive optical system has a conical or pyramidal shape, and takes in all the light from the light source from the bottom surface. The light beam is divided into light that is totally reflected and light that is transmitted. The transmitted light is deflected when it exits the refractive optical system, and is reflected to the front surface by a reflection unit installed around the refractive optical system. The totally reflected light repeats total reflection, and increases with every divergence angle total reflection with respect to the optical axis direction. And when the angle with respect to a side surface becomes smaller than a critical angle, light radiate | emits from the side surface of a refractive element. Therefore, the emission angle of the light at the time of emission is substantially the same angle. Since the inclination angle with respect to the optical axis of the concave mirror arranged outside the refractive optical system is adjusted with respect to the divergence angle shown on the left, when this light hits the concave mirror, the light beam is made parallel to the optical axis.

  However, the region where light is emitted from the refractive optical system tends to be large, and the size of the light source is not substantially reduced. As the light source area increases, it becomes difficult to suppress the subsequent divergence angle, and the light utilization efficiency decreases.

Thus, when a surface light source having a large area is used as the light source of the illumination optical system, there is a problem that it is difficult to use light effectively. The present invention provides means for solving the above problems, and provides an illumination device that can obtain high illumination efficiency even when, for example, a large area surface light source is used.
JP 2005-208571 A JP 2006-128041 A JP 2004-259541 A JP 2005-292283 A

  In order to solve the above-described problem, a light source device of the present invention includes a light source that emits light, a light beam separating unit, a first light collecting optical system, and a second light collecting optical system, When the normal passing through the center of the light emitting surface of the light source is the optical axis, the light beam separating means transmits a light beam having a small angle with respect to the optical axis and a light beam having a large angle with respect to the optical axis. The first condensing optical system has a function of condensing the light beam that has passed through the light beam separating means at one point, and the second condensing optical system. The optical system has a function of condensing a light beam totally reflected at least once by the light beam separating means at one point.

  By implementing the present invention, even if a large area light source is used, the light emitted from the light source can be collimated with less angular dispersion, and as a result, high illumination efficiency can be obtained when used in a projector illumination device. Can do.

  Next, details of the present invention will be described in accordance with the description of the embodiments.

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

  FIG. 1 shows a configuration example of a light source device according to the present invention. Reference numeral 1 denotes a surface light source, and all the light emitted from the surface light source is taken into the light beam separating means 2. As the surface light source 1, a light emitting diode, an organic EL, or a semiconductor laser, which is a so-called solid light emitting element, can be used. A one-dot chain line in FIG. 1 is a straight line passing through the center of the surface light source 1 and perpendicular to the light emitting surface, and this is defined as an optical axis. Reference numeral 5 denotes a condensing lens that collimates light having a small angle with the optical axis, and 4 is a concave mirror that collimates light having a large angle with the optical axis. Details of the beam separation means 2 will be described with reference to FIG. The light beam separating means 2 has two bottom surfaces parallel to the light source, and has a shape obtained by hollowing out a cone from a cylindrical body whose rotation center axis coincides with the optical axis. This cone is a cone having a bottom surface disposed on the top surface of the cylinder and having a vertex in a region between the two bottom surfaces of the cylinder on the optical axis. When this cone is cut out from the cylinder, FIG. It becomes a shape like 2 of. At this time, the surface constituting the light beam separating means 2 is a first surface directly facing the light emitting surface of the surface light source 1, a second surface far from the light source surface, and a side surface adjacent to both surfaces (surface indicated by a dotted line in the figure). ).

  The light guide 3 is disposed adjacent to the light beam separating means 2 as shown in FIG. The surface that is in close contact with the side surface 2 is a light incident end surface 3a, and the light incident from the incident end surface is guided to the light emitting end surface 3b that is further away from the optical axis. At this time, the area of the light emitting end face 3b is smaller than the area of the light incident end face 3a. Further, when the area of the light emitting end face 3b is compared with the area of the light source 1, the latter is smaller. Of the surfaces constituting the light guide 3, surfaces other than the light incident end surface 3 a and the light emitting end surface 3 b act as light guide surfaces that reflect and guide the internal light. The light guide 3 and the light beam separating means 2 may be integrated or separated. When integrated, there is an advantage that the manufacturing process of the element is shortened and the cost is reduced, and when separated, there is an advantage that the coating process on the surface can be individually optimized. The behavior of light emitted from the surface light source 1 in the light beam separating means 2 and the light guide 3 will be described with reference to FIGS. 3 and 4.

  In FIG. 3, only the light having a large incident angle is totally reflected by 2. Here, the light transmitted without being totally reflected is referred to as a light beam (A), and the light that is totally reflected is referred to as a light beam (B). Whether the light is in the light beam (A) or enters (B) depends on only the angle formed with the optical axis of the light, regardless of the light emitting point of the light source 1. Light having a small angle with the optical axis is (A), and light having a large angle is (B). As shown in FIG. 4, the light beam (B) is incident on the light incident end face 3a and is emitted from the light exit end face 3b. 3 compresses the light beam in the optical axis direction. The light emitted from 3 b is collimated by the concave mirror 4. Next, the relationship between the light guide 3 and the concave mirror 4 will be described with reference to FIGS. 5 and 6. FIG. 5 is a sectional view taken along a plane including the optical axis. The light emitting end face 3b of the light guide 3 is smaller than the light source, and light is emitted therefrom. Here, when a parabola whose focal point is the center position of 3b is considered, the light emitted from 3b is collimated in the optical axis direction by the parabola. Here, when a rotating body in which a parabola is rotated around the optical axis is considered, FIG. 6 is obtained. At this time, the focal points are distributed in a ring shape as indicated by 4a in the figure. Then, all the light emitted from the light emitting end face 3b is made parallel to the optical axis by the concave mirror 4. At this time, the concave mirror 4 in FIG. 6 is a reflector having a compound quadratic curved surface shape called CPC disclosed in Patent Document 2. In the present embodiment, the light emitting end surface portion 3b of the light beam separating means 2 is a ring-shaped secondary light source and spatially coincides with the focal point 4a. Furthermore, by making the area of the light emitting end face 3b smaller than the surface light source 1, the amount of deviation from the focal position of the concave mirror 4 is reduced, and the parallelism by the concave mirror 4 is improved. The light guide 3 can be made of a transparent optical material or the like. However, if light is guided to 3b only by total reflection in the light guide, the light may leak to the outside. It is desirable to form a reflective film.

  On the other hand, the light beam (A) transmitted through the light beam separating means 2 is collimated by using the condensing lens 5 of FIG. 1 (the optical main plane of the condensing lens 5 and the light emitting surface of the surface light source 1 are the condensing lens 5). The focal length of At this time, light having a large angle with the optical axis does not enter the lens due to the above-described action of the light beam separating means 2, so that the solid angle of the incident light is suppressed to be small. This reduces etendue and improves the parallelism of the light flux by the lens.

  In this embodiment, the light emitted from the light source emits a light beam regardless of the position of the light emitting point of the surface light source 1 based on the two parameters of the angle formed by the two surfaces of the light beam separating means 2a and the refractive index of the light beam separating means 2. Separation is possible at the angle between the optical axis Therefore, the light exceeding the collimating ability is not incident on the collimating means. Therefore, the parallelism of the light flux is improved and the efficiency of the illumination system is improved.

  With the configuration described above, in this embodiment, light from a surface light source can be converted into parallel light with little angular dispersion.

  Moreover, according to the desirable form of this invention, it is desirable to form a reflective Fresnel structure on the three wall surfaces. FIG. 7 is a cross-sectional view of 3 on a plane including the optical axis, and a dotted line L in the drawing is a normal line passing through the center of the emission end face 3b and lowered to the optical axis. In general, when the width of the light guide portion is narrowed, the divergence angle increases every time the light guide portion is reflected on the wall. When the divergence angle exceeds 90 °, the light travels backward through the light guide and returns to the light source direction. Therefore, a reflective Fresnel structure such as 3c is formed on the wall surface 2b as a local structure. The surface that reflects the light beam 3c is inclined so as to spread toward the light emission side. For this reason, a light beam incident at an angle of θ3 with respect to the optical axis becomes θ3 ′ (<θ3) after being reflected by the reflecting surface. Accordingly, it is desirable to prevent the light from returning by making the divergence angle smaller than the reflection angle of light when there is no reflective Fresnel structure. Further, a diffusion surface is provided at the exit port 3b. This has the effect of preventing the light beam from returning when the light beam enters the exit port at an angle greater than the critical angle.

  Further, when the area of the side surface of the light beam separating means 2 is sufficiently smaller than the area of the light source 1, the parallelism of the light collimated by the concave mirror 4 can be obtained without the light guide 3 as shown in FIG. Compared to when the focus is on. Therefore, the parallelism can be designed to be improved without the light guide 3. In this case, when considering a cross section of the light beam separating means 2 on the plane including the optical axis, the paraboloid focusing on the position that bisects the side farthest from the optical axis is rotated around the optical axis to form the concave mirror 4. Determine the shape.

  In addition, although the present Example has described the structural example of the light source device which collimates the light emitted from the light source 1, according to the situation where this light source device is applied, it emits light beams other than a parallel light beam. A light source device can also be configured.

  For example, instead of using the concave mirror 4 having a parabolic cross section, if an elliptical cross section is used and one of its focal points is arranged to coincide with the light emitting end surface portion 3b, the light emitting end surface portion 3b. The divergent light beam emitted from can be converged to the other focal position of the elliptical mirror. The same applies to the condensing lens 5. In the above configuration example, the light beam emitted from the center point of the light source 1 is arranged to be parallel, but the optical principal plane of the condensing lens 5 and the light emission of the surface light source 1 are arranged. By adjusting the distance to the surface, it is possible to generate a light beam that converges at a point away from the condenser lens 5 by a finite distance.

  A second embodiment will be described with reference to FIGS.

In this embodiment, as shown in FIG. 9, the side surface of the light beam separating means 2 is divided into six equal parts around the optical axis. For each equally divided side surface, a tapered rod lens-shaped light guide 3 is attached in which the distance between the facing surfaces decreases monotonically as the distance from the optical axis increases. By using such a light guide 3, the light source image formed on the light emitting end face is compressed not only in the optical axis direction but also in a direction perpendicular to the optical axis. A reflection Fresnel structure is formed on the light guide surface of the light guide 3 so that the light incident from the center of the light beam separating means 2 does not return to 2 as in the first embodiment. By forming the Fresnel structure, most of the energy is collected on the light emitting end face 3b (FIG. 10). At this time, the light emitting end face 3b is made smaller than 1/6 of the area of the light source 1. A concave mirror 4 is used as means for collimating the light emitted from the light emitting end face 3b. FIG. 11 shows a method for installing the light guide 3 and the concave mirror 4. The concave mirror 4 of this embodiment has a parabolic shape. The focal point 4a of the concave mirror 4 and the center of the light emitting end face 3b are made to coincide. As a result, the secondary light source is installed in the vicinity of the focal point. Furthermore, by making the area of the secondary light source smaller than one sixth of the area of the light source 1, the amount of positional deviation from the focal position is reduced, and the parallelism is improved as compared with when the light source 1 is in focus. In the first embodiment, the light source image is compressed only in the optical axis direction, but in the present embodiment, the light source image is also compressed in the direction perpendicular thereto. Thereby, the amount of deviation from the focal point is further reduced as compared with the first embodiment, and the parallelism of the light beam with respect to the optical axis is also improved. Further, the light guide 3 and the concave mirror 4 are similarly installed on the other five side surfaces divided into six equal parts. (Fig. 12)
By adopting the above structure, the parallelism of the light flux is improved, and the light utilization efficiency of the illumination system is improved.

  Also in the present embodiment, the light emitted from the light source 1 may be provided with a function of condensing at a point in the positive direction of the optical axis as well as parallelizing the light.

  The detailed implementation method of Example 3 is demonstrated using FIGS. 13-14. As shown in FIG. 13, the light transmitted through the light beam separation unit 2 of the first and second embodiments is transmitted through the surface of the light beam separation unit 2, so that the emission angle θ <b> 4 ′ is larger than the incident angle θ <b> 4 to 2. This is because the light beam separating means 2 has a negative refractive power with respect to the light incident from the light source. Therefore, as shown in FIG. 14, the correction element 6 that makes the emission angle equal to θ4 is aligned with the center line in the positive direction of the optical axis of the light beam separating means 2. Further, an air layer is placed between the light beam separating means 2 and the correction element 6 so as to be installed in the positive direction of the second optical axis. The correction element 6 has a conical shape in which the surface facing 2 is parallel and the apex is in the direction of the negative optical axis. When the material of the correction element 6 is the same as 2, when the bottom surface of the cone, which is the exit surface, is parallel to the surface facing the light source of the light beam separating means 2, the angular distribution returns to the distribution when emitted from the light source. . Therefore, the incident angle of the light transmitted through the light beam separating means 2 to the condensing lens 5 becomes smaller than when the correction element 6 is not provided. When the light transmitted through the correction element 6 is collimated by the same condenser lens as in the first embodiment, the parallelism is improved.

  Incidentally, in the present embodiment, it is assumed that the first surface facing the surface light source of the light beam separating means 2 is a flat surface. (Here, the first surface is the surface closest to the surface light source in the light beam separating means 2 of the surface light source.) However, since this surface does not participate in the light beam separation, it needs to be a plane parallel to the light emitting surface. Alternatively, a curved surface may be used as long as all or most of the light emitted from the light source 1 can be captured. An example is shown in FIG. The light beam separating means 2 has the smallest distance between the center of the irradiated surface and the second surface on the side far from the light reduction / exemption, and is inclined in the negative direction of the optical axis as the distance from the optical axis increases. By doing so, light emitted from the surface light source 1 can be captured more reliably. Further, since the light beam receives a negative refractive index by the first surface, the incident angle to the total reflection surface becomes larger than that when the first surface is a flat surface, and the amount of the light beam totally reflected increases. Conversely, if the shape is inclined in the positive direction of the optical axis as it goes away from the optical axis as shown in FIG. 16, the amount of the totally reflected light beam can be reduced. Therefore, it is effective to change the shape of the first surface of the second in order to control the ratio of the light beam directed to the concave mirror 4 and the light beam directed to the lens. Such control should be optimized in consideration of the balance with the performance of the concave mirror 4 and the lens 5.

  FIG. 17 shows an example in which a projection-type image display device (projector) is configured by using the light source device 7 configured by using the surface light source 1, the light beam separating means 2, the concave mirror 4 and the condenser lens 5 as described above. Show. This image display device illuminates a light valve capable of displaying desired image information as optical intensity information, and performs enlarged projection using a projection optical system. In this embodiment, a transmissive liquid crystal display device 8 is used as a light valve. The liquid crystal display device 8 is illuminated by the light source device 7 and the image information displayed on the transmissive liquid crystal display device 8 is enlarged and projected by the projection optical system 10 to allow the observer to observe a good image. be able to. When the liquid crystal display device 8 is used as described above, generally, when the liquid crystal display device is illuminated, the contrast of the image has a smaller angle variation of the illumination light and becomes higher near the vertical incidence. Also, the characteristics of other optical elements that make up the projector are often optimized to maximize efficiency when light is incident at an angle. Since the light source device 7 that we configured can obtain parallel light with little angular dispersion of light rays even when a large area surface light source is used as described above, the above projection type image display device (projection type image) When used as a light source device for a display device, a bright image with high contrast can be obtained.

Conceptual diagram of Example 1 Shape of parallel separation element 2 in embodiment 1 Behavior of light in the light beam separation means 2 used in the first embodiment Optical path diagram in the light beam separation means 2 used in Example 1 Positional relationship between the concave mirror and the light beam separating means in the first embodiment (plan view) Positional relationship between the concave mirror and the light beam separating means in the first embodiment (perspective view) Fresnel structure inside the light guide of the light beam separating means of embodiment 1 Variation without light guide Positional relationship between the light guide and the light beam separating means in the second embodiment FIG. 7 is an optical path diagram inside the light guide according to the second embodiment. Positional relationship between light guide and reflector in Example 2 The optical path figure when attaching a Fresnel to the light guide of Example 2. FIG. Behavior of light immediately after passing through the light beam separating means of the first embodiment Behavior of light when the light flux correction element of Example 3 is used Variation 1 of beam separation means Variation 2 of beam separation means Projection type image display device application example Conceptual diagram of conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface light source 2 Light beam separation means 3 Light guide 3a Light incident end surface 3b Light output end surface 3c Reflective Fresnel 4 Concave mirror 4a Focus 5 Condensing lens 6 Correction optical element 7 Light source device 8 Transmission type liquid crystal display device 10 Projection optical system 101 Surface light source 102 Condensing lens

Claims (20)

A light source that emits light, a beam separation means,
Having a first condensing optical system and a second condensing optical system;
When the normal line passing through the center of the light emitting surface of the light source is the optical axis,
The luminous flux separating means is a luminous flux incident from the light source,
Transmits a light beam having a small angle with respect to the optical axis,
An optical element that totally reflects a light beam having a large angle with respect to the optical axis at least once,
The first condensing optical system has a function of condensing the light beam transmitted through the light beam separating unit at one point, and the second condensing optical system is performed at least once by the light beam separating unit. A light source device having a function of condensing a totally reflected light beam at one point. The light beam separating means is made of an optically transparent optical material,
A first surface that transmits light from the light source; a second surface that selectively reflects or transmits light transmitted through the first surface according to an incident angle thereof;
Having three kinds of surfaces, side surfaces adjacent to both the first surface and the second surface;
The second surface is closest to the light emitting surface of the light source at the intersection with the optical axis;
The light source device according to claim 1, wherein the light source device has an inclination that is farthest from the light emitting surface at a position of a line of intersection with the side surface. The light beam separating means is made of an optically transparent optical material,
A first surface that transmits light from the light source; two surfaces that selectively or totally reflect light transmitted through the first surface according to an incident angle; and the first surface and the second surface. It has three types of side surfaces adjacent to both sides,
The second surface is closest to the first surface at the intersection with the optical axis;
2. The light source device according to claim 1, wherein the light source device has an inclination that is farthest from the first surface at a position of a line of intersection with the side surface. The light source device according to claim 1, wherein the light beam separating unit has a rotationally symmetric shape about the optical axis. The light beam separating means includes
From a cylinder having a bottom surface parallel to the light emitting surface of the light source,
Having a vertex in a region sandwiched between two bottom surfaces of the cylindrical body on the optical axis;
5. The light source device according to claim 4, wherein the light source device has a shape in which a conical portion having a bottom surface disposed on a bottom surface far from the light source of the cylindrical body is hollowed out. A light guide having a light incident end face, a light exit end face, and a light guide face adjacent to these two faces,
The side surface of the light beam separating means is coincident with the light incident end surface,
The light exit end face is located farther from the optical axis than the light incident end face;
The light source device according to claim 1, further comprising a light guide having a total area of the light emitting end surface smaller than a total area of the light incident end surface. The light source device according to claim 6, wherein a total area of the light emitting end surface is smaller than a total area of a light emitting surface of the light source.   The light source device according to claim 6, wherein the light guide has a rotationally symmetric shape with the optical axis as an axis. The light source device according to claim 6, wherein a length of the light emitting end face in a direction parallel to the optical axis is smaller than a length of the light incident end face in a direction parallel to the optical axis. The light guide is divided into a plurality of parts,
The light source device according to claim 6, wherein an area of each light emitting end face of the plurality of light guides is smaller than an area of each light incident end face of the plurality of light guides. The second condensing optical system is a concave mirror,
A cross-sectional shape by a plane including the optical axis is a parabola,
The light source device according to claim 6, wherein a focal position of the parabola coincides with a center point of a light emitting surface of the light guide. The light source device according to claim 11, wherein the second condensing optical system has a rotationally symmetric shape with the optical axis as an axis. The second condensing optical system is the same number of concave mirrors as the plurality of light guides,
The cross-sectional shape by the plane including the center point of the light emitting end face of the optical axis and the light guides is a parabola,
The light source device according to claim 10, wherein a focal position of each parabola coincides with a center point of a light emitting surface of each of the plurality of light guides. The second condensing optical system has a rotationally symmetric shape about a straight line passing through each center point of the light emitting end faces of the plurality of light guides parallel to the optical axis. The light source device described.   The light source device according to claim 6, wherein a light reflection film is formed on the light guide surface of the light guide.   The light source device according to claim 6, wherein the light guide is integrated with the light beam separating unit.   The light source device according to claim 1, wherein the first condensing optical system includes a lens having a positive refractive power.   The light source device according to claim 1, wherein the second condensing optical system includes a concave mirror.   The light source device according to claim 1, wherein the light source is a solid light emitting element. The light source device according to any one of claims 1 to 19,
A light valve irradiated with illumination light emitted from the light source device;
A projection type image display apparatus comprising: a projection optical system that enlarges and projects an image formed on the light valve onto a screen.

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