Light source optical system, light source unit, light source device and image display device

Abstract

To provide a light source optical system which improves illuminance distribution using a simple configuration.SOLUTION: A light source optical system is provided, comprising a first optical system (22, 23, 24, 25, 30, 31, 32, 33) for guiding a first luminous flux emitted from a light source (20) to a wavelength conversion element (26), and a second optical system (23, 24, 25, 27, 30, 31, 32, 33) for a second luminous flux (LF) wavelength-converted by the wavelength conversion element to pass, the second optical system having light guide members (23, 30, 31, 32, 33) for separating a portion of the second luminous flux in the second optical system.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a light source optical system, a light source unit, a light source device, and an image display device. [Background technology]

[0002] Projectors (image display devices, image projection devices) that enlarge and project images are now widely used. A projector focuses light emitted from a light source onto an image display element (spatial light modulator) such as a digital micromirror device (DMD) or liquid crystal display element, and the light emitted from the image display element is modulated by a video signal and displayed as a color image on a screen, which is the projection surface.

[0003] Traditionally, high-intensity ultra-high pressure mercury lamps have been used as the light source for projectors, but they have a short lifespan and require frequent maintenance. For this reason, in recent years, an increasing number of projectors have been using lasers or LEDs as light sources instead of ultra-high pressure mercury lamps. Lasers and LEDs have the advantage of a longer lifespan than ultra-high pressure mercury lamps, and their monochromaticity allows for better color reproduction.

[0004] For example, when forming an image by irradiating an image display element with the three primary colors of red, green, and blue, it is possible to generate all three colors using a laser light source, but there is a problem that the light emission efficiency of green and red lasers is lower than that of blue lasers. For this reason, a method is used in which a blue laser is used as excitation light to irradiate a phosphor, and red light and green light are generated from the fluorescent light that is wavelength-converted by the phosphor. Light source devices using such laser light sources and phosphors are disclosed in Patent Documents 1 and 2, etc. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6090875 [Patent Document 2] Patent No. 6364916 Summary of the Invention [Problem to be solved by the invention]

[0006] This type of light source device is required to have as uniform an illuminance distribution on the irradiation surface as possible, and the light source optical system in the conventional light source device has room for improvement in terms of unevenness in the illuminance distribution on the irradiation surface.

[0007] In particular, in projectors, the illuminance distribution on the image display element, which is the surface illuminated by light from the light source optical system, can affect the illuminance distribution on the screen. Furthermore, in addition to the light source optical system, the projection optical system and other components also affect the illuminance distribution. In other words, the illuminance unevenness on the screen, which is a problem for projectors, can be caused either by the light source device or by the projection optical system and other components that precede the light source device. For example, in an ultra-short focus projector that includes a folding mirror in the projection optical system, the angle of incidence of the projected light on the screen varies greatly depending on the vertical height, which makes it easy for illuminance unevenness to occur above and below the screen.

[0008] The present invention has been made based on the above-mentioned awareness of the problems, and has an object to provide a light source optical system, a light source unit, a light source device, and an image display device that can improve the illuminance distribution with a simple configuration. [Means for solving the problem]

[0009] An aspect of the light source optical system of the present invention includes a first optical system that causes a first light flux emitted from a light source to be incident on a wavelength conversion element; The aforementioned a second optical system through which the second light flux wavelength-converted by the wavelength conversion element passes, The aforementioned In the second optical system, The aforementioned A part of the second beam The aforementioned The second optical system includes a separate light guide member. The light-guiding member has a parallel plane plate shape, and when viewed from the wavelength conversion element side along the optical axis of the second optical system, has a first surface with a large projected area, a second surface with a small projected area, a third surface opposite the first surface, and a fourth surface opposite the second surface, and a part of the separated second light beam enters the second surface, is totally reflected multiple times by the first surface and the third surface inside the light-guiding member, and is emitted from the fourth surface, and when viewed along the optical axis of the second optical system, both the second surface and the fourth surface are located within the range of the optical path through which the second light beam passes.

[0010] In one aspect of the light source unit of the present invention, a first light flux emitted from a light source is incident on a wavelength conversion element by a first optical system; The aforementioned The second light beam whose wavelength has been converted by the wavelength conversion element is emitted through a second optical system, The aforementioned In the second optical system, The aforementioned A part of the second beam The aforementioned The second optical system includes a separate light guide member. The light-guiding member has a parallel plane plate shape, and when viewed from the wavelength conversion element side along the optical axis of the second optical system, has a first surface with a large projected area, a second surface with a small projected area, a third surface opposite the first surface, and a fourth surface opposite the second surface, and a part of the separated second light beam enters the second surface, is totally reflected multiple times by the first surface and the third surface inside the light-guiding member, and is emitted from the fourth surface, and when viewed along the optical axis of the second optical system, both the second surface and the fourth surface are located within the range of the optical path through which the second light beam passes.

[0011] An aspect of the light source device of the present invention includes a light source and The aforementioned a first optical system that causes a first light flux emitted from the light source to be incident on a wavelength conversion element; The aforementioned a second optical system through which the second light flux wavelength-converted by the wavelength conversion element passes, The aforementioned In the second optical system, The aforementioned A part of the second beam The aforementioned The second optical system includes a separate light guide member. The light-guiding member has a parallel plane plate shape, and when viewed from the wavelength conversion element side along the optical axis of the second optical system, has a first surface with a large projected area, a second surface with a small projected area, a third surface opposite the first surface, and a fourth surface opposite the second surface, and a part of the separated second light beam enters the second surface, is totally reflected multiple times by the first surface and the third surface inside the light-guiding member, and is emitted from the fourth surface, and when viewed along the optical axis of the second optical system, both the second surface and the fourth surface are located within the range of the optical path through which the second light beam passes.

[0012] An aspect of the image display device of the present invention includes a first optical system that forms an optical path along which a first light flux passes from a light source to a wavelength conversion element; The aforementioned a light source device including a second optical system that forms an optical path through which a second light flux that has been wavelength-converted by the wavelength conversion element passes; The aforementioned an image display element that forms an image by modulating light from a light source device; The aforementioned a projection optical system that projects an image onto a projection surface; The aforementioned In the second optical system, The aforementioned A part of the second beam The aforementioned The second optical system includes a separate light guide member. The light-guiding member has a parallel plane plate shape, and when viewed from the wavelength conversion element side along the optical axis of the second optical system, has a first surface with a large projected area, a second surface with a small projected area, a third surface opposite the first surface, and a fourth surface opposite the second surface, and a part of the separated second light beam enters the second surface, is totally reflected multiple times by the first surface and the third surface inside the light-guiding member, and is emitted from the fourth surface, and when viewed along the optical axis of the second optical system, both the second surface and the fourth surface are located within the range of the optical path through which the second light beam passes. [Effects of the Invention]

[0013] According to the light source optical system, light source unit, light source device, and image display device of the present invention, it is possible to improve the illuminance distribution with a simple configuration. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram illustrating the configuration of a projector (image display device). [Figure 2] 1 is a schematic configuration diagram showing a light source device according to a first embodiment. [Figure 3] 1A and 1B are diagrams showing the structure of a phosphor wheel that constitutes a light source device, in which (A) is a front view and (B) is a cross-sectional view. [Figure 4] 3 is a side cross-sectional view showing the arrangement and function of the light guide member of the first embodiment. FIG. [Figure 5] FIG. 2 is a front view showing the arrangement of the light guide member according to the first embodiment. [Figure 6] 5A and 5B are diagrams illustrating the results of improving the illuminance distribution by the light source device of the first embodiment. [Figure 7] FIG. 10 is a schematic configuration diagram showing a light source device according to a second embodiment. [Figure 8] 10 is a side cross-sectional view showing the arrangement and function of a light guide member according to a second embodiment. FIG. [Figure 9] FIG. 10 is a front view showing the arrangement of the light guide member according to the second embodiment. [Figure 10] 10A and 10B are diagrams illustrating the results of improving the illuminance distribution by the light source device of the second embodiment. [Figure 11] FIG. 10 is a front view showing the arrangement of light guide members in a light source device according to a third embodiment. [Figure 12] FIG. 10 is a schematic configuration diagram showing a light source device according to a fourth embodiment. [Figure 13] 10 is a side cross-sectional view showing the arrangement and function of a light guide member according to a fourth embodiment. FIG. [Figure 14] FIG. 10 is a front view showing the arrangement of light guide members according to a fourth embodiment. [Figure 15] 10A and 10B are diagrams illustrating the results of improving the illuminance distribution by the light source device of the fourth embodiment. [Figure 16] FIG. 10 is a schematic configuration diagram showing a light source device according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 shows the overall structure of a projector, which is an example of an image display device. Fig. 2 and subsequent figures show embodiments of a light source device (light source optical system) that constitutes the projector, with Figs. 2 to 6 showing a first embodiment, Figs. 7 to 10 showing a second embodiment, Fig. 11 showing a third embodiment, Figs. 12 to 15 showing a fourth embodiment, and Fig. 16 showing a fifth embodiment.

[0016] 1 includes a housing 11, a light source device (light source unit) 12, a light uniformizing element 13, an illumination optical system 14, an image display element 15, and a projection optical system 16. Each of the components from the light source device 12 to the projection optical system 16 is housed inside the housing 11.

[0017] The light source device 12 emits light containing wavelengths corresponding to the colors red (R), green (G), and blue (B), for example. The internal configuration of the light source device 12 will be described in detail later.

[0018] The light homogenizing element 13 homogenizes the light emitted from the light source device 12 by mixing the light. As the light homogenizing element 13, for example, a light tunnel made up of a combination of four mirrors, a rod integrator made of cylindrical glass or the like, or a fly's eye lens in which multiple lenses are arranged in a matrix, etc., can be used.

[0019] The illumination optical system 14 substantially uniformly illuminates the image display element 15 with the light homogenized by the light homogenizing element 13. The illumination optical system 14 has, for example, one or more lenses and one or more reflecting surfaces.

[0020] The image display element 15 has a light valve such as a digital micromirror device (DMD), a transmissive liquid crystal panel, a reflective liquid crystal panel, etc. The image display element 15 forms an image by modulating the light illuminated by the illumination optical system 14 (light from the light source device 12).

[0021] The projection optical system 16 enlarges and projects the image formed by the image display element 15 onto a screen (projection surface) 17 outside the projector 10. The projection optical system 16 has, for example, one or more lenses.

[0022] 2 is a schematic diagram showing the configuration of light source device 12 according to the first embodiment. Light source device 12 has, arranged in this order in the light propagation direction, a laser light source (light source) 20, a collimator lens 21, a first lens group 22, a light-guiding member 23, a quarter-wave plate 24, a second lens group 25, a phosphor wheel (wavelength conversion element) 26, a third lens group 27, and a color wheel 28. For example, a light source optical system is configured by the components (optical elements) of light source device 12 excluding laser light source 20.

[0023] The laser light source 20 has multiple light sources (solid-state light sources). In FIG. 2, six light sources are drawn lined up in the vertical direction of the drawing, but in reality, six light sources are lined up in n rows (n is a number equal to or greater than 2) in the direction perpendicular to the paper surface (depth direction), and 6 × n light sources are arranged in a two-dimensional array. The number of multiple laser light sources 20 can be set arbitrarily. Also, instead of multiple laser light sources 20, a single high-output laser light source can be used.

[0024] The multiple laser light sources 20 can be configured as a light source unit in which multiple light sources are arranged in an array on a substrate, for example, but there is a degree of freedom in the specific form. Hereinafter, multiple light sources arranged in a two-dimensional array may be referred to as "multiple laser light sources 20."

[0025] The multiple laser light sources 20 emit, for example, light in the blue band (blue laser light) with a central wavelength of 455 nm in emission intensity as excitation light BL (first colored light) that excites phosphors provided in fluorescent region 26d (FIG. 3), which is a wavelength conversion region of phosphor wheel 26. The blue laser light emitted from the multiple laser light sources 20 is linearly polarized light with a constant polarization state, and is arranged so as to be S-polarized with respect to the incident surface (surface 23a, described later) of light-guiding member 23. The blue laser light emitted from the multiple laser light sources 20 is coherent light. Note that the excitation light BL emitted from the multiple laser light sources 20 may be light with a wavelength that can excite the phosphors in fluorescent region 26d of phosphor wheel 26, and is not limited to light in the blue band.

[0026] A plurality of collimator lenses 21 are arranged in a two-dimensional array corresponding to the plurality of laser light sources 20. The plurality of collimator lenses 21 adjust the light beams (excitation light BL) emitted from the plurality of laser light sources 20 to become parallel light or convergent light. The number of collimator lenses 21 only needs to correspond to the number of light sources of the laser light source 20, and can be increased or decreased according to an increase or decrease in the number of light sources of the laser light source 20.

[0027] The first lens group 22 has positive power as a whole, and includes a positive lens 22a and a negative lens 22b in that order in the propagation direction of light from the laser light source 20 toward the phosphor wheel 26. The first lens group 22 converges the excitation light BL that has entered as parallel light or convergent light from the collimator lens 21, and guides the convergent light to the light-guiding member 23. The first lens group 22 may have negative power instead of positive power.

[0028] The light-guiding member 23 is located on the optical path between the first lens group 22 and the second lens group 25. The light-guiding member 23 is a flat (plate-type) polarized beam splitter, and is coated so as to reflect S-polarized light (first polarized component) in the wavelength band of the excitation light BL guided from the first lens group 22, while transmitting P-polarized light (second polarized component) in the wavelength band of the excitation light BL and the fluorescent light YL (second colored light) from the phosphor wheel 26.

[0029] In this embodiment, the light-guiding member 23 reflects S-polarized light in the wavelength band of the excitation light BL and transmits P-polarized light, but conversely, it may be configured to reflect P-polarized light in the wavelength band of the excitation light BL and transmit S-polarized light.

[0030] The quarter-wave plate 24 is disposed with its optical axis tilted by 45 degrees with respect to the linearly polarized light of the excitation light BL reflected by the light-guiding member 23. The quarter-wave plate 24 converts the linearly polarized light of the excitation light BL reflected by the light-guiding member 23 into circularly polarized light.

[0031] The second lens group 25 has positive power overall, and includes a positive lens 25a and a positive lens 25b in that order in the propagation direction of light from the laser light source 20 toward the phosphor wheel 26. The second lens group 25 converges and guides the excitation light BL, which has been converted into circularly polarized light by the quarter-wave plate 24 and is incident thereon, to the phosphor wheel 26.

[0032] Excitation light BL guided from second lens group 25 is incident on phosphor wheel 26. Fig. 3 is a diagram showing the detailed structure of phosphor wheel 26. Phosphor wheel 26 has disk member 26a and drive motor 26c that drives disk member 26a to rotate around rotation axis 26b. Disk member 26a can be, for example, a transparent substrate or a metal substrate (aluminum substrate, etc.), but is not limited to these.

[0033] The disk member 26a of the phosphor wheel 26 is partitioned into a fluorescent region 26d over a large portion of its circumferential direction (an angular range greater than 270° in this embodiment), and a portion of its circumferential direction excluding the range of the fluorescent region 26d (an angular range less than 90° in this embodiment) is partitioned into an excitation light reflection region 26e.

[0034] The fluorescent region 26d is configured by laminating, from the bottom to the top, a reflective coating 26d1, a phosphor layer 26d2, and an anti-reflection coating 26d3.

[0035] The reflective coating 26d1 has the property of reflecting light in the wavelength region of the fluorescent light YL emitted by the phosphor layer 26d2. If the disk member 26a is made of a metal substrate with high reflectivity, it is possible to omit the reflective coating 26d1 (to give the disk member 26a the function of the reflective coating 26d1).

[0036] The phosphor layer 26d2 may be, for example, a phosphor material dispersed in an organic or inorganic binder, a phosphor material crystallized directly, or a rare earth phosphor such as Ce:YAG. The wavelength band of the fluorescent light YL emitted by the phosphor layer 26dd2 may be, for example, yellow, blue, green, or red. In this embodiment, however, a case where fluorescent light YL having a yellow wavelength band is used is illustrated. Furthermore, although a phosphor is used as the wavelength conversion element in this embodiment, a phosphor, a nonlinear optical crystal, or the like may also be used.

[0037] The anti-reflection coating 26d3 has the property of preventing light from being reflected on the surface of the phosphor layer 26d2.

[0038] A reflective coating 26e1 having a property of reflecting light in the wavelength region of the excitation light BL guided from the second lens group 25 is laminated on the excitation light reflection region 26e. If the disk member 26a is made of a metal substrate with high reflectivity, it is possible to omit the reflective coating 26e1 (to give the disk member 26a the function of the reflective coating 26e1).

[0039] By rotating disk member 26a using drive motor 26c, the irradiation position of excitation light BL moves over time on phosphor wheel 26. As a result, the excitation light BL incident on phosphor wheel 26 is time-shared between a state in which it is converted into fluorescent light YL having a different wavelength from the excitation light BL in fluorescent region 26d and emitted, and a state in which it is reflected as excitation light BL by excitation light reflecting region 26e and emitted.

[0040] The number and range of fluorescent regions 26d and excitation light reflecting regions 26e can be freely determined, and various design modifications are possible. For example, two fluorescent regions and two excitation light reflecting regions may be alternately arranged at 90° intervals in the circumferential direction.

[0041] The light source device 12 will be described again with reference to Figure 2. The excitation light BL reflected by the excitation light reflecting region 26e of the phosphor wheel 26 becomes circularly polarized light in the reverse direction and travels from the phosphor wheel 26 toward the light-guiding member 23. The second lens group 25 converts the diffused light beam into a substantially parallel light beam, and the quarter-wave plate 24 converts the P-polarized light into P-polarized light. The excitation light BL converted into P-polarized light passes through the light-guiding member 23 and enters the color wheel 28 through the third lens group 27, which has a light-collecting effect. In this embodiment, the third lens group 27 is composed of a single lens.

[0042] The excitation light BL incident on the fluorescent region 26d of the phosphor wheel 26 is converted into fluorescent light YL and emitted. This fluorescent light YL is converted from a diffused light beam into a substantially parallel light beam by the second lens group 25, passes through the quarter-wave plate 24 and the light-guiding member 23, and enters the color wheel 28 through the third lens group 27.

[0043] The color wheel 28 includes a disk member 28a and a drive motor 28c that rotates the disk member 28a around a rotation axis 28b. Although not shown, the disk member 28a has blue, yellow, red, and green regions that are partitioned circumferentially. The blue region corresponds to the excitation light reflection region 26e of the phosphor wheel 26, while the yellow, red, and green regions are synchronized to correspond to the fluorescent region 26d of the phosphor wheel 26. The yellow region transmits light in the yellow wavelength range emitted from the phosphor wheel 26 as is. The red and green regions each use a dichroic mirror to reflect light in the yellow wavelength range and other unnecessary wavelengths, thereby obtaining light of a high purity color.

[0044] 1, light of each color generated in a time-division manner by color wheel 28 is guided (irradiated) from light uniformizing element 13 through illumination optical system 14 to image display element 15, where it forms an image corresponding to each color. A color image is obtained by projecting the image onto screen 17 in an enlarged form by projection optical system 16. That is, image display element 15 modulates light from light source device 12 to form an image, and projection optical system 16 projects the image formed by image display element 15 onto screen 17 in an enlarged form.

[0045] In the light source optical system of the light source device 12 constituting the above projector 10, the first lens group 22 to the second lens group 25 form a first optical system for making the first light flux emitted from the laser light source 20 incident on the phosphor wheel 26 (forming an optical path through which the first light flux passes). Note that the collimator lens 21 may be included in the first optical system.

[0046] In the light source optical system of light source device 12, second lens group 25 to third lens group 27 form a second optical system through which the second light flux whose wavelength has been converted by phosphor wheel 26 passes (forming an optical path through which the second light flux passes). The optical axis LX of the second optical system and second light flux LF are shown in Figures 2, 4, and 5. Figure 5 is a front view of light-guiding member 23 as viewed along the optical axis LX from the phosphor wheel 26 side.

[0047] In the first optical system, the light-guiding member 23 functions as a reflecting element that reflects the first light flux incident from the first lens group 22 side toward the phosphor wheel 26 side. In the second optical system, the light-guiding member 23 functions as a light-guiding element that guides a part of the second light flux traveling from the second lens group 25 toward the third lens group 27 and separates it within the second optical system. The configuration and function of the light-guiding member 23 will be described below.

[0048] The light-guiding member 23 has a plane-parallel plate shape made of glass, transparent resin, or the like, and has a front surface 23a and a back surface 23b, which are planes parallel to each other, on the front and back sides. In order for the light-guiding member 23 to function as a polarizing beam splitter, a coating is formed on the front surface 23a side so as to reflect S-polarized light in the wavelength band of the excitation light BL and transmit P-polarized light in the wavelength band of the excitation light BL and the fluorescent light YL.

[0049] The peripheral portion of the light guide member 23 is constituted by a pair of parallel long-side end faces (first end faces) 23c and 23d extending in the longitudinal direction of the light guide member 23, and a pair of parallel short-side end faces 23e and 23f extending in the lateral direction of the light guide member 23. The long-side end faces 23c and 23d, and the short-side end faces 23e and 23f are surfaces that are approximately perpendicular to the front surface 23a and the back surface 23b, respectively. The long-side end faces 23c and 23d are also surfaces that are approximately perpendicular to the short-side end faces 23e and 23f. The light guide member 23 is supported and fixed near the short-side end faces 23e and 23f by support means (not shown) outside the second light flux LF.

[0050] The direction in which the optical axis of the first lens group 22 extends is defined as the M1 direction. The M1 direction is perpendicular to the optical axis LX of the second optical system. The light guide member 23 is disposed with its longitudinal direction facing the M2 direction, which is perpendicular to the M1 direction and the optical axis LX.

[0051] 4, light-guiding member 23 is disposed so that front surface 23a and back surface 23b form an intersection angle of approximately 45 degrees with respect to optical axis LX when viewed from the side in direction M2 (the side of short side end surface 23e or short side end surface 23f). In the direction along optical axis LX, front surface 23a is located on the phosphor wheel 26 (second lens group 25) side, and back surface 23b is located on the color wheel 28 (third lens group 27) side.

[0052] 5, in a front view of light guide member 23 along optical axis LX, surface 23a and long side end face 23c face toward phosphor wheel 26. Surface 23a, which has a larger projected area in this front view, is a first surface, and long side end face 23c, which has a smaller projected area, is a second surface. The back surface 23b opposite to the front surface 23a is the third surface, and the long side end surface 23d opposite to the long side end surface 23c is the fourth surface. The first light beam is reflected toward the phosphor wheel 26 by the surface 23a, which is the first surface.

[0053] 5, the rear surface 23b and the long side end surface 23d face toward the third lens group 27 (color wheel 28). The projected area of ​​the rear surface 23b is larger than that of the long side end surface 23d.

[0054] The light-guiding member 23 is disposed such that the optical axis LX passes through the center of its outer shape in the front and rear views. More specifically, in the front view of the light-guiding member 23 shown in Fig. 5, the optical axis LX is located at the center of the short-side dimension from the long-side end face 23c to the long-side end face 23d, and the optical axis LX is located at the center of the long-side dimension from the short-side end face 23e to the short-side end face 23f. As shown in Fig. 5, when an imaginary plane S1 that includes the optical axis LX and extends along the M1 direction and an imaginary plane S2 that includes the optical axis LX and extends along the M2 direction are set, the light-guiding member 23 in the front and rear views has a symmetrical shape with respect to both the imaginary plane S1 and the imaginary plane S2 (the imaginary plane S1 passes through the center of the light-guiding member 23 in the long direction, and the imaginary plane S2 passes through the center of the light-guiding member 23 in the short direction).

[0055] In the M1 direction, the entire short-side dimension of the light-guiding member 23 in a front view is within the range of the second light flux LF. That is, in the M1 direction, both the long-side end surface 23c and the long-side end surface 23d are located within the range of the optical path through which the second light flux LF passes.

[0056] In the M2 direction, the longitudinal dimension of the light guide member 23 is slightly larger than the beam diameter of the second beam LF, and parts of the light guide member 23 near both ends in the longitudinal direction are located outside the range of the second beam LF.

[0057] Therefore, the front surface 23a and the back surface 23b and the long side end surfaces 23c and 23d of the light guide member 23 are located within the range of the second light flux LF, except for parts near both ends in the M2 direction (longitudinal direction). In contrast, the short side end surfaces 23e and 23f are located outside the range of the second light flux LF.

[0058] The second light beam LF, which is composed of fluorescent light YL wavelength-converted in fluorescent region 26d of phosphor wheel 26 and excitation light BL reflected by excitation light reflecting region 26e, is converted from a diffused light beam into a substantially parallel light beam by second lens group 25 and reaches light-guiding member 23. As shown in FIG. 5, the majority of the area of ​​light-guiding member 23 that is located on second light beam LF is front surface 23a and back surface 23b, and in this area, light-guiding member 23 transmits second light beam LF as is toward third lens group 27. Light-guiding member 23 further has long side end surface 23c at a position where a portion of second light beam LF is incident from the phosphor wheel 26 side.

[0059] As shown in FIG. 4 , a portion of the second light beam LF enters the light-guiding member 23 from the long side end surface 23c, propagates within the light-guiding member 23 while undergoing multiple total reflections, and is emitted from the long side end surface 23d. Specifically, the light that enters the light-guiding member 23 from the long side end surface 23c is reflected multiple times by the front surface 23a and the back surface 23b, and is guided to the long side end surface 23d. In this way, the light-guiding member 23 not only transmits the second light beam LF directly through the front surface 23a and the back surface 23b, but also separates a portion of the second light beam LF within the second optical system. As a result, in the second optical system, the light amount distribution of the second light beam LF differs before and after the light-guiding member 23.

[0060] More specifically, the light-guiding member 23 has the incident-side long-side end face 23c located in one region in the M1 direction divided by the imaginary plane S2 shown in Fig. 5, and the exit-side long-side end face 23d located in the other region in the M1 direction. Therefore, the light-guiding member 23 guides a part of the second light flux LF from one region to the other region across the imaginary plane S2.

[0061] By providing the light-guiding member 23 functioning as described above in the second optical system, it is possible to change the illuminance distribution on the irradiation surface (image display element 15) of the illumination light emitted from the light source device 12. Then, by appropriately managing the direction and degree of light guiding by the light-guiding member 23, it is possible to improve the illuminance distribution on the irradiation surface (image display element 15).

[0062] The light guide member 23 reflects the first light beam emitted from the laser light source 20 in the first optical system toward the phosphor wheel 26, and is provided in the second optical system to separate a part of the second light beam LF. Therefore, an improvement in illuminance distribution can be achieved with a simple configuration with a small number of parts.

[0063] The light-guiding member 23 guides a portion of the second light beam LF within the optical path of the second optical system (inside the beam diameter of the second light beam LF). This prevents a loss of light intensity caused by the light-guiding member 23, and improves the illuminance distribution without reducing the light utilization efficiency of the light source device 12.

[0064] Furthermore, by causing the light to be totally reflected multiple times when guided by the light guide member 23, it is possible to obtain the effect of increasing the range of variation in the illuminance distribution.

[0065] 5, the light-guiding member 23 has a size in the longitudinal direction that crosses the beam diameter of the second light beam LF. Therefore, in the longitudinal direction (direction M2) of the light-guiding member 23, the effect of the light-guiding member 23 can be obtained for the entire second light beam LF.

[0066] In projector 10, there is a correlation between the illuminance distribution of illumination light at image display element 15 and the illuminance distribution on screen 17. By setting the light separation action of light guide member 23 in the second optical system in consideration of the influence of projection optical system 16 and the like on the illuminance distribution, it is possible to improve the light distribution characteristics of not only light source device 12 but also projector 10 as a whole, and reduce uneven illuminance on screen 17.

[0067] FIG. 6 shows the results of experiments and measurements demonstrating the effect of the light-guiding member 23. FIG. 6 shows the illuminance distributions on the screen 17 for an example in which the light-guiding member 23 is used to separate (guide) a portion of the second light flux LF, and a comparative example in which the light-guiding member 23 is not used to separate (guide) the second light flux LF. In the example, the long-side end faces 23c and 23d of the light-guiding member 23 are configured as light-transmitting surfaces, allowing light to enter the light-guiding member 23 from the long-side end face 23c and exit from the long-side end face 23d. In the comparative example, the long-side end faces 23c and 23d of the light-guiding member 23 are configured as light-absorbing surfaces, preventing light from entering the light-guiding member 23 from the long-side end face 23c and light from exiting from the long-side end face 23d. Projection onto the screen 17 was performed under the same conditions except for the above, resulting in the illuminance distribution shown in FIG. 6.

[0068] 6, the variation in illuminance distribution is smaller in the example than in the comparative example, and the illuminance unevenness on the screen 17 is improved. In particular, in the region from the center to the upper left part of the screen 17, the lack of light amount that occurred in the comparative example is improved in the example.

[0069] As an example, the illuminance distribution on screen 17 is evaluated as follows. First, the maximum value of the illuminance on screen 17 is normalized to 100%. Then, the area on screen 17 onto which projection is performed by projector 10 is equally divided into nine rectangular regions, and the average value of the illuminance is calculated for each region. Furthermore, the average value of the illuminance of the nine regions is calculated. By referring to the values ​​calculated in this way, the unevenness of the illuminance on screen 17 can be quantitatively evaluated.

[0070] 6 shows the average illuminance values ​​for each of the nine regions on the screen 17 in the example, and Table 2 shows the average illuminance values ​​for each of the nine regions on the screen 17 in the comparative example. The average illuminance values ​​calculated based on the data in Tables 1 and 2 were 88.0% for the example and 86.9% for the comparative example, which means that the unevenness of the illuminance distribution on the screen 17 in the example is reduced compared to the comparative example.

[0071] In this embodiment, the angle between the normal to the second surface (long side end surface 23c) of light guiding member 23 and the optical axis LX of the second optical system is 45 degrees, the average length W3 of the second surface (long side end surface 23c) in a direction perpendicular to the ridge line between the first surface (surface 23a) and the second surface (long side end surface 23c) of light guiding member 23 is 0.9 mm, and the diameter φ of the second luminous flux LF at the position of the ridge line between the first surface (surface 23a) and the second surface (long side end surface 23c) of light guiding member 23 of the second optical system is 0.9 mm. L The diameter of the second beam LF is 20 mm. L is the diameter (beam diameter) of the second beam LF in a plane perpendicular to the optical axis LX at the end position of the light-guiding member 23 on the phosphor wheel 26 (wavelength conversion element) side. where: When the light guide member is projected onto a plane perpendicular to the optical axis of the second optical system, the average length of the second surface in a direction perpendicular to the ridge line between the first surface and the second surface is defined as W2, The diameter of the second light beam on the optical surface immediately before the light guide member of the second optical system is φ L , The distance between the optical axis of the second optical system and the center line of the long side of the incident side surface (23c) of the long side end surface of the light guide member is H i , The distance between the optical axis of the second optical system and the center line of the long side of the light-guiding member on the exit side (23d) is defined as H o , When W2=0.64mm φ L =20mm H i =7.07mm H o =7.07mm Therefore, W2 / φ L =0.032 This becomes:

[0072] W2 / φ L is a measure of the amount of light guided by the light guide member, and it is desirable that the following conditional expression (1) be satisfied. (1) 0.018 <W2 / φ L <0.035

[0073] W2 / φ L If W2 / φ is less than 0.018, the amount of light guided will be too small to obtain the desired effect. L If is greater than 0.032, the amount of light guided becomes too large, which may adversely affect the luminous flux.

[0074] It is more preferable to satisfy the following conditional expression (2): (2) 0.022 <W2 / φ L <0.033

[0075] It should be noted that the evaluation of the illuminance distribution on the screen 17 may be performed using a method different from that described above. For example, the number of regions on the screen 17 from which the average illuminance value is obtained may be set to a number other than nine. Furthermore, the shape of each region on the screen 17 may be a shape other than an equally divided rectangle.

[0076] 7 is a schematic diagram showing the configuration of a light source device 12 according to the second embodiment. The light source device 12 of the second embodiment includes a light guide member 30 instead of the light guide member 23 of the first embodiment.

[0077] The light-guiding member 30 is disposed eccentrically with respect to the optical axis LX in the traveling direction (M1 direction) of the first light flux from the laser light source 20 toward the light-guiding member 30. The light-guiding member 30 is not a polarizing beam splitter like the light-guiding member 23, but is a dichroic mirror that reflects light in the wavelength band of the excitation light BL and transmits light in the wavelength band of the fluorescent light YL. No quarter-wave plate is provided between the light-guiding member 30 and the second lens group 25. These are the differences between the first embodiment and the second embodiment. The rest of the configuration is the same as that of the light source device 12 of the first embodiment, and a description of the common parts will be omitted.

[0078] The light-guiding member 30 is a plane-parallel plate made of glass, transparent resin, or the like, and has a front surface 30a and a back surface 30b, which are planes parallel to each other, on the front and back sides. To enable the light-guiding member 30 to function as a dichroic mirror, the front surface 30a side is coated with a coating that reflects light in the wavelength band of the excitation light BL and transmits light in the wavelength band of the fluorescent light YL.

[0079] 9, when an imaginary plane S1 that includes the optical axis LX and extends along the M1 direction and an imaginary plane S2 that includes the optical axis LX and extends along the M2 direction are set, the light-guiding member 30 in a front view and a rear view along the optical axis LX has a shape that is symmetrical with respect to the imaginary plane S1 (the imaginary plane S1 passes through the center of the light-guiding member 30 in the longitudinal direction). On the other hand, the light-guiding member 30 in a front view and a rear view does not overlap with the imaginary plane S2 and is positioned offset from the optical axis LX in the M1 direction.

[0080] A first light beam emitted from the laser light source 20 is incident on the phosphor wheel 26 via a first optical system including the first lens group 22 to the second lens group 25. A second light beam having a wavelength converted by the phosphor wheel 26 is incident on the color wheel 28 through a second optical system including the second lens group 25 to the third lens group 27. In the second optical system, only the fluorescent light YL passes through the light guiding member 30 in the region where the light guiding member 30 is disposed, whereas both the fluorescent light YL and the excitation light BL reach the color wheel 28 in the region where the light guiding member 30 is not disposed. Because the light guiding member 30 is disposed eccentrically in the M1 direction with respect to the optical axis LX, the excitation light BL can pass through a wide region of the second optical system, including the vicinity of the optical axis LX.

[0081] 8 and 9, the peripheral portion of the light guide member 30 is configured with a pair of parallel long-side end faces (first end faces) 30c and 30d extending in the longitudinal direction, and a pair of parallel short-side end faces 30e and 30f extending in the lateral direction. The long-side end faces 30c and 30d, and the short-side end faces 30e and 30f are surfaces that are approximately perpendicular to the front surface 30a and the back surface 30b, respectively. The long-side end faces 30c and 30d are also surfaces that are approximately perpendicular to the short-side end faces 30e and 30f. The light guide member 30 is supported and fixed near the short-side end faces 30e and 30f by support means (not shown) outside the second light flux LF.

[0082] 8, light guide member 30 is disposed so that front surface 30a and back surface 30b form an angle of approximately 45 degrees with respect to optical axis LX when viewed from the side in direction M2 (the side of short side end surface 30e or short side end surface 30f). In the direction along optical axis LX, front surface 30a is positioned on the phosphor wheel 26 (second lens group 25) side, and back surface 30b faces the color wheel 28 (third lens group 27) side.

[0083] 9, in a front view of the light guide member 30 along the optical axis LX, the surface 30a and the long side end face 30c face the phosphor wheel 26. The surface 30a, which has a larger projected area in this front view, is the first surface, and the long side end face 30c, which has a smaller projected area, is the second surface. The back surface 30b opposite to the front surface 30a is the third surface, and the long side end surface 30d opposite to the long side end surface 30c is the fourth surface. The first light beam is reflected toward the phosphor wheel 26 by the surface 30a, which is the first surface.

[0084] 9, the rear surface 30b and the long side end surface 30d face the third lens group 27 (color wheel 28). The rear surface 30b has a larger projected area than the long side end surface 30d.

[0085] In the M1 direction, the entire short-side dimension of the light-guiding member 30 in a front view is within the range of the second light flux LF. That is, in the M1 direction, both the long-side end face 30c and the long-side end face 30d are located within the range of the optical path through which the second light flux LF passes.

[0086] In the M2 direction, the longitudinal dimension of the light guide member 30 is slightly larger than the beam diameter of the second beam LF, and parts of the light guide member 30 near both ends in the longitudinal direction are located outside the range of the second beam LF.

[0087] Therefore, the front surface 30a, the back surface 30b, and the long side end surfaces 30c, 30d of the light guide member 30 are located within the range of the second light flux LF, except for parts near both ends in the M2 direction (longitudinal direction). In contrast, the short side end surfaces 30e, 30f are located outside the range of the second light flux LF.

[0088] 8, a portion of the second light flux LF enters the light-guiding member 30 from the long side end face 30c, propagates within the light-guiding member 30 while undergoing multiple total reflections, and is emitted from the long side end face 30d. That is, the light-guiding member 30 separates a portion of the second light flux LF within the second optical system. As a result, in the second optical system, the light amount distribution of the second light flux LF differs before and after the light-guiding member 30.

[0089] Unlike the light-guiding member 23 of the first embodiment, the light-guiding member 30 is disposed eccentrically in the direction M1 without intersecting with the optical axis LX. The long-side end surface 30c, onto which a portion of the second light flux LF is incident, is located closer to the periphery of the second light flux LF. The long-side end surface 30d, from which the light propagating through the light-guiding member 30 emerges, is located closer to the center and closer to the optical axis LX. Therefore, the light-guiding member 30 functions to move the portion of the second light flux LF that passes through the periphery closer to the optical axis LX in the direction M1. In other words, the light-guiding member 30 in the second optical system adjusts the illuminance distribution so as to brighten the central areas of the image display element 15 and the screen 17.

[0090] The light-guiding member 30 has a size in the longitudinal direction that crosses the beam diameter of the second light beam LF. Therefore, in the longitudinal direction (direction M2) of the light-guiding member 30, the effect of the light-guiding member 30 can be obtained for the entire second light beam LF.

[0091] FIG. 10 shows the results of experiments and measurements demonstrating the effect of the light-guiding member 30. FIG. 10 shows the illuminance distribution on the screen 17 for an example in which a portion of the second light flux LF is separated (guided) using the light-guiding member 30, and a comparative example in which the image display element 15 is not separated (guided) by the light-guiding member 30. In the example, the long side end faces 30c and 30d of the light-guiding member 30 are configured as light-transmitting surfaces, allowing light to enter the light-guiding member 30 from the long side end face 30c and exit from the long side end face 30d. In the comparative example, the long side end faces 30c and 30d of the light-guiding member 30 are configured as light-absorbing surfaces, preventing light from entering the light-guiding member 30 from the long side end face 30c and light from exiting from the long side end face 30d. Projection onto the screen 17 was performed under the same conditions except for the above, resulting in the illuminance distribution shown in FIG. 10.

[0092] 10, the variation in illuminance distribution is smaller in the Example than in the Comparative Example, and the illuminance unevenness on the screen 17 is improved. In particular, in the region near the upper center of the screen 17, the Example has a wider range where a higher light intensity can be obtained than the Comparative Example.

[0093] The unevenness of the illuminance on the screen 17 was evaluated using the same evaluation criteria as in the first embodiment. Table 3 in FIG. 10 shows the average value of the illuminance in each of the nine regions on the screen 17 in the example, and Table 4 shows the average value of the illuminance in each of the nine regions on the screen 17 in the comparative example. In the second embodiment, the average value of the illuminance calculated based on the data in Tables 3 and 4 was 90.8% in the example and 90.0% in the comparative example, and the unevenness of the illuminance distribution on the screen 17 was reduced in the example compared to the comparative example.

[0094] In this embodiment, the angle between the normal to the second surface (long side end surface 30c) of the light guiding member 30 and the optical axis LX is 45 degrees, the average length W3 of the second surface (long side end surface 30c) in a direction perpendicular to the ridge line between the first surface (surface 30a) and the second surface (long side end surface 30c) of the light guiding member 30 is 0.7 mm, and the diameter φ of the second light flux LF at the position of the ridge line between the first surface (surface 30a) and the second surface (long side end surface 30c) of the light guiding member 30 of the second optical system is 0.7 mm. L The diameter of the second beam LF is 20 mm. L is the diameter (beam diameter) of the second beam LF in a plane perpendicular to the optical axis LX at the end position of the light-guiding member 30 on the phosphor wheel 26 (wavelength conversion element) side. Therefore, W2=0.49mm φ L =20mm H i =8.04mm H o =0.96mm Therefore, W2 / φ L =0.025 and satisfies the above conditional expressions (1) and (2).

[0095] 11 shows only the arrangement of the light guide member 31 in a front view (and a rear view) along the optical axis LX of the third embodiment of the light source device 12. The configuration other than the light guide member 31 is the same as that of the second embodiment, and illustration and description of common parts are omitted.

[0096] The light guide member 31 is a parallel flat plate made of glass, transparent resin, or the like, and its surface 31a (First page) , back side 31b (Third side) , long side end face ( The second aspect, First end surface) 31c, long side end surface ( The fourth aspect, Second end face 31d, short side end face 31e, and short side end face 31f correspond to faces 30a to 30f of light guide member 30 of the second embodiment, respectively.

[0097] The light-guiding member 31 has an asymmetric shape with respect to both an imaginary plane S1 that includes the optical axis LX and extends along the M1 direction, and an imaginary plane S2 that includes the optical axis LX and extends along the M2 direction. More specifically, like the light-guiding member 30 of the second embodiment, the light-guiding member 31 is disposed eccentrically with respect to the optical axis LX in the M1 direction (without overlapping with the imaginary plane S2). Furthermore, the short-side end face 31e of the light-guiding member 31 is positioned closer to the imaginary plane S2 than the short-side end face 31f, and the short-side end face 31e is positioned within the range of the second light flux LF. In other words, the light-guiding member 31 has an asymmetric shape with respect to the position of the optical axis LX of the second optical system (imaginary plane S1) in the direction (M2 direction) in which the long-side end faces 31c and 31d extend. In the M2 direction, there are regions where the light guiding member 31 is located within the second light flux LF and can guide light, and regions where the light guiding member 31 does not overlap with the second light flux LF and does not guide light. The light guiding member 31 is supported and fixed near a short side end surface 31f that is outside the range of the second light flux LF by a support means (not shown).

[0098] The imaginary plane S1 is a plane (longitudinal to both the long side end surface 31c and the long side end surface 31d) that includes the optical axis LX of the second optical system and also includes the light fluxes before and after being separated (guided) by the light-guiding member 31. By including such asymmetry with respect to the imaginary plane S1 (asymmetry with respect to the optical axis LX in the M2 direction) in the requirements for setting the position of the light-guiding member 31, the degree of freedom in changing the illuminance distribution on the image display element 15 and the screen 17 is improved.

[0099] Although the light-guiding member 31 shown in FIG. 11 has an asymmetric shape with respect to both the imaginary plane S1 and the imaginary plane S2, it is also possible to use a light-guiding member that is symmetric with respect to the imaginary plane S2 and asymmetric with respect to only the imaginary plane S1.

[0100] 12 is a schematic diagram showing the configuration of a light source device 12 according to a fourth embodiment. The light source device 12 of the fourth embodiment differs from the third embodiment only in the arrangement of the light guide member 32. Other than the arrangement of the light guide member 32, the light source device 12 is the same as the third embodiment, and a description of the common parts will be omitted.

[0101] 13 and 14 are diagrams illustrating the arrangement of the light guide member 32 according to the fourth embodiment. (First page) , back side 32b (Third side) , long side end surface 32c (Second surface, first end surface) , long side end face 32d (4th surface, 2nd end surface) , short-side end surface 32e, and short-side end surface 32f are surfaces corresponding to the surfaces 31a to 31f of light-guiding member 31, respectively. The arrangement of light-guiding member 32 in the fourth embodiment differs from that in the third embodiment in that light-guiding member 32 is arranged closer to the first optical system than imaginary plane S2 that includes optical axis LX and extends along direction M2. The rest of the configuration is the same as that of light source device 12 in the third embodiment, and a description of common parts will be omitted. Note that light-guiding member 32 is supported and fixed by support means (not shown) near short-side end surface 32f, which is outside the range of second light flux LF.

[0102] 13, a portion of the second light flux LF enters the light-guiding member 32 from the long side end face 32c, propagates within the light-guiding member 32 while undergoing multiple total reflections, and is emitted from the long side end face 32d. That is, the light-guiding member 32 separates a portion of the second light flux LF within the second optical system. As a result, in the second optical system, the light amount distribution of the second light flux LF differs before and after the light-guiding member 32.

[0103] 13, in the light-guiding member 32, the long side end surface 32c, onto which a portion of the second light flux LF is incident, is located toward the center and close to the optical axis LX. Furthermore, the long side end surface 32d, from which the light propagating through the light-guiding member 32 emerges, is located toward the periphery of the second light flux LF. Therefore, the light-guiding member 32 functions to redirect a portion of the second light flux LF that passes through the center away from the optical axis LX in the direction M1. In other words, the light-guiding member 32 in the second optical system adjusts the illuminance distribution so as to brighten the peripheries of the image display element 15 and the screen 17.

[0104] FIG. 15 shows the results of experiments and measurements demonstrating the effect of the light-guiding member 32 of the fourth embodiment. FIG. 15 shows the illuminance distribution on the screen 17 for an example in which a portion of the second light flux LF is separated (guided) using the light-guiding member 32, and a comparative example in which the image display element 15 is not separated (guided) by the light-guiding member 32. In the example, the long-side end faces 32c and 32d of the light-guiding member 32 are configured as light-transmitting surfaces, allowing light to enter the light-guiding member 32 from the long-side end face 32c and exit from the long-side end face 32d. In the comparative example, the long-side end faces 32c and 32d of the light-guiding member 32 are configured as light-absorbing surfaces, preventing light from entering the light-guiding member 32 from the long-side end face 32c and from exiting from the long-side end face 32d. Projection onto the screen 17 was performed under the same conditions except for the above, resulting in the illuminance distribution shown in FIG. 15.

[0105] 15, the variation in illuminance distribution is smaller in the Example than in the Comparative Example, and the illuminance unevenness on the screen 17 is improved. In particular, in the region near the upper center of the screen 17, the Example has a wider range where a higher light intensity can be obtained than the Comparative Example.

[0106] The unevenness of the illuminance on the screen 17 was evaluated using the same evaluation criteria as in the first embodiment. Table 5 in Fig. 15 shows the average value of the illuminance in each of the nine regions on the screen 17 in the example, and Table 6 shows the average value of the illuminance in each of the nine regions on the screen 17 in the comparative example. In the fourth embodiment, the average value of the illuminance calculated based on the data in Tables 5 and 6 was 89.4% in the example and 89.1% in the comparative example, and the unevenness of the illuminance distribution on the screen 17 was reduced in the example compared to the comparative example.

[0107] In this embodiment, the angle between the normal to the second surface (long side end surface 32c) of the light guiding member 32 and the optical axis (LX) of the second optical system is 45 degrees, the average length W3 of the second surface (long side end surface 32c) in a direction perpendicular to the ridge line between the first surface (surface 32a) and the second surface (long side end surface 32c) of the light guiding member 32 is 0.7 mm, and the diameter φ of the second light flux (LF) at the position of the ridge line between the first surface (surface 32a) and the second surface (long side end surface 32c) of the light guiding member 32 of the second optical system is 0.7 mm. L The diameter of the second beam LF is 21 mm. L is the diameter (beam diameter) of the second beam LF in a plane perpendicular to the optical axis LX at the end position of the light-guiding member 32 on the phosphor wheel 26 (wavelength conversion element) side. Therefore, W2=0.49mm φ L =21mm H i =0.96mm H o =8.04mm Therefore, W2 / φ L =0.024 and satisfies the above conditional expressions (1) and (2). Also, H i / φ L =0.046 This becomes:

[0108] H i / φ L is an index representing the position in the light beam through which the region separated in the second light beam by the light-guiding member passes, and when the light is guided by the light-guiding member so as to move away from the optical axis, it is desirable to satisfy the following conditional expression (3): (3) H i / φ L <0.1

[0109] Generally, the amount of light in the second light flux LF is large near the optical axis LX, so when guiding the light away from the optical axis LX using a light-guiding member, guiding the light from near the optical axis LX is easier to adjust in order to reduce illuminance unevenness. If the ratio is greater than 0.1, the light will be farther away from the optical axis LX, making it difficult to reduce illuminance unevenness.

[0110] In the fourth embodiment, the arrangement of the light-guiding member 32 guides the light from the central portion (the portion close to the optical axis LX) of the second luminous flux LF to the peripheral portion (the portion far from the optical axis LX), so that the distribution of the luminous flux LF can be adjusted when the amount of light in the central portion of the luminous flux LF is strong. This makes it possible to adjust the illuminance distribution of the image display element 15 and the screen 17 to be uniform.

[0111] 16 is a schematic diagram showing a light source device 12 according to a fifth embodiment. The light source device 12 of the fifth embodiment is similar to that of the fourth embodiment in that the arrangement of the light guide member 33 guides the light from the central portion (the portion close to the optical axis LX) of the second light beam LF to the peripheral portion (the portion far from the optical axis LX). (First page) , back side 33b (Third side) , long side end surface 33c (Second surface, first end surface) , long side end face 33d (4th surface, 2nd end surface) are surfaces corresponding to the surfaces 32a to 32d of the light guide member 32, respectively.

[0112] The fifth embodiment differs from the fourth embodiment in that the angle between the optical axis LX and the normal to the second surface (long side end surface 33c) of the light-guiding member 33 is set to 35 degrees, and the optical axis of the first optical system is tilted by 20 degrees (the angle of incidence of the first surface (surface 33a) of the light-guiding member 33 is tilted to 55 degrees) so that the first light flux reflected by the first surface (surface 33a) of the light-guiding member 33 is incident on the wavelength conversion element (phosphor wheel 26). That is, the normal to the second surface (long side end surface 33c) of the light-guiding member 33 is closer to the direction of the optical axis LX of the second optical system than in the fourth embodiment. Also, the normal to the first surface (surface 33a) of the light-guiding member 33 is farther from the direction of the optical axis LX of the second optical system. That is, the angle between the normal to the second surface (long side end surface 33c) and the optical axis LX of the second optical system is 35 degrees, and the angle between the normal to the first surface (surface 33a) and the second optical axis LX is 55 degrees. Therefore, the angle between the normal to the second surface (long side end surface 33c) and the optical axis LX of the second optical system is smaller than the angle between the normal to the first surface (surface 33a) and the optical axis LX of the second optical system. The rest of the configuration is the same as that of light source device 12 of the fourth embodiment, and a description of the common parts will be omitted.

[0113] 16, the arrangements of the laser light source 20, the collimator lens 21, and the first lens group 22 are adjusted to match the arrangement of the light-guiding member 33. The excitation light BL emitted from the first lens group 22 is reflected by the first surface (surface 33a) of the light-guiding member 33, and enters the second lens group 25 along the optical axis LX.

[0114] In the light source device 12 of the fifth embodiment, the angle between the normal to the second surface (long side end surface 33c) of the light guide member 33 and the optical axis LX is 35 degrees, the average length W3 of the second surface (long side end surface 33c) in a direction perpendicular to the ridge line between the first surface (surface 33a) and the second surface (long side end surface 33c) of the light guide member 33 is 0.7 mm, and the diameter φ of the second light flux LF at the position of the ridge line between the first surface (surface 33a) and the second surface (long side end surface 33c) of the light guide member 33 of the second optical system is L The diameter of the second beam LF is φ Lis the diameter (beam diameter) of the second beam LF in a plane perpendicular to the optical axis LX at the end position of the light-guiding member 33 on the phosphor wheel 26 (wavelength conversion element) side. Therefore, W2=0.57mm φ L =20mm H i =1.63mm H o =7.37mm Therefore, W2 / φ L =0.029 and satisfies the above conditional expressions (1) and (2).

[0115] Also, H i / φ L =0.082 This satisfies the above conditional expression (3).

[0116] In the light source device 12 of the fifth embodiment, the angle between the normal to the second surface (long side end surface 33c) of the light guide member 33 and the optical axis LX of the second optical system is made smaller than the angle between the normal to the first surface (surface 33a) and the optical axis LX of the second optical system, thereby increasing the amount of light that is incident on the second surface (long side end surface 33c) and guided by the light guide member 33 out of the total amount of light of the second light beam LF. L Therefore, the light source device 12 of the fifth embodiment can adjust the light amount distribution of the light flux LF more efficiently by the light guide member 33.

[0117] In each of the above embodiments, the long side end faces 23c (30c, 31c, 32c, 33c) and the long side end faces 23d (30d, 31d, 32d, 33d) of the light guide members 23 (30, 31, 32, 33) are parallel to each other. This configuration is preferable because the incident and exit directions of the light separated by the light guide members 23 (30, 31, 32, 33) in the second optical system are aligned. However, the first end faces corresponding to the long side end faces 23c (30c, 31c, 32c, 33c) are parallel to each other. (Second side) and a second end face corresponding to the long side end face 23d (30d, 31d, 32d, 33d). (Fourth side)It is also possible to have a non-parallel relationship.

[0118] In each of the above-described embodiments, the long-side end faces 23c (30c, 31c, 32c, 33c) and the long-side end faces 23d (30d, 31d, 32d, 33d) of the light-guiding member 23 (30, 31, 32, 33) are surfaces perpendicular to the front surface 23a (30a, 31a, 32a, 33a) and the back surface 23b (30b, 31b, 32b, 33b). In the first to fourth embodiments, the long-side end faces 23c (30c, 31c, 32c) and the long-side end faces 23d (30d, 31d, 32d) are disposed at an angle of approximately 45 degrees with respect to the optical axis LX of the second optical system. In contrast to this, the first end faces of the light-guiding member (Second side) and the second end face (Fourth side) For example, as in the fifth embodiment, the angle of the first end face with respect to the optical axis LX may be set to an angle other than 45 degrees. (Second side) and the second end face (Fourth side) By setting the angle to be greater than 45 degrees (a steeper angle), the projected area when viewed along the optical axis LX becomes larger, and the proportion of the second light beam LF that is separated by the light-guiding member can be increased.

[0119] The present invention is particularly useful in image display devices (projectors) that project an image onto a projection surface, but can also be applied to devices other than image display devices as long as an improvement in illuminance distribution is required. In other words, the present invention can be applied to light source optical systems, light source units, light source devices, etc. that do not include a projection optical system or the like as a component. Furthermore, in the light source optical system, light source unit, and light source device of the present invention, the light emitted from the light source may be used for purposes other than image projection.

[0120] Although the above-described embodiments are examples of application to a projector, and the evaluation criteria are the illuminance distribution on a screen onto which an image is projected by the projector as shown in Figures 6 and 10, improvement in illuminance distribution may also be determined at a location other than the screen. For example, performance evaluation of the light source optical system, light source unit, and light source device can also be performed by measuring the illuminance distribution at the location of the image display element 15 (the irradiation surface irradiated with light from the light source device 12) in the above-described embodiments.

[0121] Although the light source device 12 of the above embodiment emits light of multiple colors in a time-division manner, the light source device and light source unit of the present invention are not limited to the type that emits light of multiple colors in a time-division manner.

[0122] The present invention has been described above using embodiments and modifications based on the accompanying drawings, but the present invention is not limited to the above-described embodiments and modifications, and various modifications and applications can be made without departing from the spirit of the present invention. In the above-described embodiments, the configurations illustrated in the accompanying drawings are not limited to these, and can be modified as appropriate within the scope of the effects of the present invention. In addition, the present invention can be modified as appropriate without departing from the spirit of the present invention. [Explanation of symbols]

[0123] 10 Projector (image display device) 12 Light source device (light source unit) 13 Light uniformizing element 14 Illumination optical system 15 Image display element 16 Projection optical system 17 Screen (projection surface) 20 Laser light source (light source) 21 Collimator lens 22 First lens group (first optical system) 23 Light guide member (first optical system, second optical system) 23a Surface (first surface) 23b Back side (Third side) 23c Long side end face (second face, first end face) 23d Long side end face ( The fourth aspect, Second end face) 24 1 / 4 wave plate (first optical system, second optical system) 25 Second lens group (first optical system, second optical system) 26 Phosphor wheel (wavelength conversion element) 27 Third lens group (second optical system) 28 Color Wheel 30 Light guide member (first optical system, second optical system) 30a Surface (first surface) 30b back side (Third side) 30c Long side end face (second face, first end face) 30d Long side end face ( The fourth aspect, Second end face) 31 Light guide member (first optical system, second optical system) 31a Surface (first surface) 31b back side (Third side) 31c Long side end face (second face, first end face) 31d Long side end face ( The fourth aspect, Second end face) 32 Light guide member (first optical system, second optical system) 32a Surface (first surface) 32b back side (Third side) 32c Long side end face (second face, first end face) 32d Long side end face ( The fourth aspect, Second end face) 33 Light guide member (first optical system, second optical system) 33a Surface (first surface) 33b back side (Third side) 33c Long side end face (second face, first end face) 33d Long side end face ( The fourth aspect, Second end face) LF Second beam LX Optical axis of the second optical system

Claims

1. a first optical system that causes a first light flux emitted from the light source to be incident on a wavelength conversion element; a second optical system through which the second light flux wavelength-converted by the wavelength conversion element passes; A light source optical system having: a light guiding member that separates a part of the second light flux within the second optical system is provided in the second optical system; the light guiding member has a parallel plane plate shape, and when the light guiding member is viewed from the wavelength conversion element side along the optical axis of the second optical system, the light guiding member has a first surface having a large projected area, a second surface having a small projected area, a third surface opposite to the first surface, and a fourth surface opposite to the second surface; a part of the separated second light flux is incident on the second surface, is totally reflected by the first surface and the third surface inside the light-guiding member multiple times, and is emitted from the fourth surface; a light source optical system, characterized in that, when viewed along an optical axis of the second optical system, the second surface and the fourth surface are both located within a range of an optical path through which the second light flux passes.

2. 2. The light source optical system according to claim 1, wherein the following condition is satisfied: 0.018<W ２ / φ Ｌ <0.035 where: W ２ represents an average value of the length of the second surface in a direction perpendicular to the ridge line between the first surface and the second surface when the light guiding member is projected onto a plane perpendicular to the optical axis of the second optical system, φ Ｌ represents the beam diameter of the second beam on a plane perpendicular to the optical axis of the second optical system at the end position of the light guiding member on the wavelength conversion element side.

3. 3. The light-source optical system according to claim 1, wherein the first surface of the light-guiding member reflects the first light flux toward the wavelength conversion element.

4. 4. The light source optical system according to claim 1, wherein the light guiding member is arranged at a position intersecting an optical axis of the second optical system, and guides a portion of the second light flux from one region to another region on either side of a plane including the optical axis.

5. 4. The light-source optical system according to claim 1, wherein the light guide member directs a part of the second light beam toward an optical axis of the second optical system.

6. 4. The light-source optical system according to claim 1, wherein the light-guiding member directs a part of the second light beam away from the optical axis of the second optical system.

7. The light source optical system according to claim 1 , wherein the light guide member has an asymmetric shape with respect to the position of the optical axis of the second optical system in the direction in which the second surface and the fourth surface extend.

8. The angle between the normal to the second surface and the optical axis of the second optical system is 2. The light source optical system according to claim 1, wherein the angle is smaller than the angle formed between the normal to the first surface and the optical axis of the second optical system.

9. A light source unit that causes a first light beam emitted from a light source to be incident on a wavelength conversion element by a first optical system, and emits a second light beam that has been wavelength-converted by the wavelength conversion element through a second optical system, a light guiding member that separates a part of the second light flux within the second optical system is provided in the second optical system; the light guiding member has a parallel plane plate shape, and when the light guiding member is viewed from the wavelength conversion element side along the optical axis of the second optical system, the light guiding member has a first surface having a large projected area, a second surface having a small projected area, a third surface opposite to the first surface, and a fourth surface opposite to the second surface; a part of the separated second light flux is incident on the second surface, is totally reflected by the first surface and the third surface inside the light-guiding member multiple times, and is emitted from the fourth surface; A light source unit characterized in that, when viewed along the optical axis of the second optical system, both the second surface and the fourth surface are located within a range of an optical path through which the second light beam passes.

10. A light source and a first optical system that causes a first light flux emitted from the light source to be incident on a wavelength conversion element; a second optical system through which the second light flux wavelength-converted by the wavelength conversion element passes; A light source device having a light guiding member that separates a part of the second light flux within the second optical system is provided in the second optical system; the light guiding member has a parallel plane plate shape, and when the light guiding member is viewed from the wavelength conversion element side along the optical axis of the second optical system, the light guiding member has a first surface having a large projected area, a second surface having a small projected area, a third surface opposite to the first surface, and a fourth surface opposite to the second surface; a part of the separated second light flux is incident on the second surface, is totally reflected by the first surface and the third surface inside the light-guiding member multiple times, and is emitted from the fourth surface; a light source device characterized in that, when viewed along the optical axis of the second optical system, the second surface and the fourth surface are both located within a range of an optical path through which the second light beam passes.

11. a light source device including a first optical system that forms an optical path along which a first light beam passes from a light source to a wavelength conversion element, and a second optical system that forms an optical path along which a second light beam that has been wavelength-converted by the wavelength conversion element passes; an image display element that modulates the light from the light source device to form an image; a projection optical system that projects the image onto a projection surface; An image display device having a light guiding member that separates a part of the second light flux within the second optical system is provided in the second optical system; the light guiding member has a parallel plane plate shape, and when the light guiding member is viewed from the wavelength conversion element side along the optical axis of the second optical system, the light guiding member has a first surface having a large projected area, a second surface having a small projected area, a third surface opposite to the first surface, and a fourth surface opposite to the second surface; a part of the separated second light flux is incident on the second surface, is totally reflected by the first surface and the third surface inside the light-guiding member multiple times, and is emitted from the fourth surface; an optical axis of the second optical system, the second surface and the fourth surface being located within a range of an optical path through which the second light beam passes.

Images