Light source device and projector

Abstract

To provide a light source device excellent in light utilization efficiency.SOLUTION: The light source apparatus according to the present disclosure includes a first light source that outputs first light, a wavelength converter that converts the first light into second light, a first optical layer that transmits the first light and reflects the second light, a second light source that outputs third light, a light guide section that guides the second light and the third light, a parallelizing system that parallelizes the third light, and a second optical layer that transmits the third light and reflects the second light. The wavelength conversion element has a first surface and a second surface facing opposite to each other, and a third surface crossing the first surface and the second surface. The first light enters the third surface of the wavelength conversion element via the first optical layer. The second light travels through the light guide portion and is emitted from a region on the first surface side of the light guide portion. The third light is collimated by the collimating optical system, then enters the area located on the second surface side of the light guide section via the second optical layer, then proceeds through the light guide section in a direction parallel to the third surface, and is then emitted from the area located on the first surface side of the light guide section.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a light source device and a projector. [Background technology]

[0002] As a light source device for use in a projector, a light source device that utilizes fluorescence emitted from a phosphor when the phosphor is irradiated with excitation light emitted from a light-emitting element has been proposed. Patent Document 1 listed below discloses a light source device that includes a first light source that emits excitation light, a phosphor rod that wavelength-converts the excitation light to yellow light, a second light source that emits blue light, and a transparent rod that transmits yellow light and blue light. Patent Document 1 describes that in this light source device, white light, which is a combination of yellow light and blue light, can be extracted from the transparent rod by turning on the first light source and the second light source. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-9981 Summary of the Invention [Problem to be solved by the invention]

[0004] The light source device of Patent Document 1 has a blue light-emitting diode (LED) constituting a second light source, which is arranged facing the side surface of a transparent rod. Blue light is incident on the side surface of the transparent rod and emitted from the end surface. However, with this configuration, the blue light has many angular components, and many angular components are incident on the side surface of the transparent rod at angles of incidence smaller than the critical angle before reaching the end surface of the transparent rod. This causes a problem in that much of the blue light leaks out from the side surface of the transparent rod, reducing the utilization efficiency of the blue light. Furthermore, the leakage of blue light causes an imbalance between the amount of yellow light and the amount of blue light, making it difficult to obtain the desired white light. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, a light source device according to one embodiment of the present invention includes: a first light source that emits first light in a first wavelength band; a wavelength conversion element that converts the first light into second light in a second wavelength band different from the first wavelength band; a first optical layer that is disposed between the first light source and the wavelength conversion element and that transmits the first light and reflects the second light; a second light source that emits third light in a third wavelength band different from the second wavelength band; a light guide that is disposed between the first optical layer and the wavelength conversion element and that guides the second light converted by the wavelength conversion element and the third light emitted from the second light source; a collimating optical system that is disposed between the second light source and the light guide and that collimates the third light to make it incident on the light guide; and a second optical layer that is disposed between the collimating optical system and the light guide and that transmits the third light and reflects the second light. The wavelength conversion element has first and second surfaces that face opposite each other and a third surface that intersects the first and second surfaces. The first light emitted from the first light source is incident on the third surface of the wavelength conversion element through the first optical layer. The second light converted by the wavelength conversion element travels through the light guiding unit and is emitted from the region on the first surface side of the light guiding unit. The third light emitted from the second light source is collimated by the collimating optical system, is incident on the region on the second surface side of the light guiding unit through the second optical layer, travels through the light guiding unit in a direction parallel to the third surface, and is emitted from the region on the first surface side of the light guiding unit.

[0006] A projector according to one aspect of the present invention comprises a light source device according to one aspect of the present invention, an optical modulation device that modulates light emitted from the light source device, and a projection optical device that projects the light modulated by the optical modulation device. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic configuration diagram of a projector according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the light source device of the first embodiment. [Figure 3]3 is a cross-sectional view of the light source device taken along line III-III in FIG. 2. FIG. [Figure 4] FIG. 10 is a cross-sectional view of a light source device according to a second embodiment. [Figure 5] 5A and 5B are schematic diagrams showing the intensity distribution of blue light in a wavelength conversion element and a light guide section. [Figure 6] FIG. 10 is a cross-sectional view of a light source device according to a third embodiment. [Figure 7] 5A and 5B are schematic diagrams showing the intensity distribution of blue light in a wavelength conversion element and a light guide section. [Figure 8] FIG. 10 is a cross-sectional view of a light source device according to a fourth embodiment. [Figure 9] 5A and 5B are schematic diagrams showing the intensity distribution of blue light in a wavelength conversion element and a light guide section. [Figure 10] FIG. 10 is a cross-sectional view of a light source device according to a fifth embodiment. [Figure 11] FIG. 10 is a cross-sectional view of a light source device according to a sixth embodiment. [Figure 12] FIG. 13 is a cross-sectional view of a light source device according to a seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] [First embodiment] A first embodiment of the present invention will be described below with reference to the drawings. The projector of this embodiment is an example of a projector that uses a liquid crystal panel as a light modulation device. In the drawings below, the dimensions of some components may be shown on different scales to make them easier to see.

[0009] FIG. 1 is a schematic configuration diagram of a projector 10 according to the present embodiment. 1, the projector 10 of this embodiment is a projection-type image display device that displays a color image on a screen SCR, which is a projection surface. The projector 10 is equipped with three light modulation devices corresponding to red light LR, green light LG, and blue light LB.

[0010] The projector 10 includes an illumination device 20, a color separation light-guiding optical system 200, a red light optical modulation device 400R, a green light optical modulation device 400G, a blue light optical modulation device 400B, a light combining element 500, and a projection optical device 600.

[0011] The illumination device 20 includes a light source device 30A, an integrator optical system 90, a polarization conversion element 93, and a superimposing optical system 94. The illumination device 20 emits white light LW containing red light LR, green light LG, and blue light LB. The specific configuration of the illumination device 20 will be described later.

[0012] In the following drawings, an XYZ Cartesian coordinate system will be used as necessary. The X axis is an axis parallel to the optical axis AX1 of the lighting device 20 and extends along the front-to-rear direction of the projector 10. The Y axis is an axis perpendicular to the X axis and extends along the up-down direction of the projector 10. The Z axis is an axis perpendicular to the X and Y axes and extends along the left-to-right direction of the projector 10. These notations are used to explain the positional relationship of the components of the projector 10 and do not limit the installation posture or direction of the projector 10. The optical axis AX1 of the lighting device 20 is the central axis of the white light LW emitted from the lighting device 20.

[0013] In the following explanation, one of the two directions along the X axis will be referred to as the +X direction, and the opposite direction will be referred to as the -X direction. One of the two directions along the Y axis will be referred to as the +Y direction, and the opposite direction will be referred to as the -Y direction. One of the two directions along the Z axis will be referred to as the +Z direction, and the opposite direction will be referred to as the -Z direction. When referring to two directions along the X axis collectively without distinction, they will be referred to as the X-axis direction. When referring to two directions along the Y axis collectively without distinction, they will be referred to as the Y-axis direction. When referring to two directions along the Z axis collectively without distinction, they will be referred to as the Z-axis direction.

[0014] The color separation and light-guiding optical system 200 includes a first dichroic mirror 210, a second dichroic mirror 220, a first reflecting mirror 230, a second reflecting mirror 240, a third reflecting mirror 250, a first relay lens 260, and a second relay lens 270. The color separation and light-guiding optical system 200 separates white light LW emitted from the illumination device 20 into red light LR, green light LG, and blue light LB, and guides the red light LR to a red light optical modulation device 400R, the green light LG to a green light optical modulation device 400G, and the blue light LB to a blue light optical modulation device 400B.

[0015] A field lens 300R is disposed between the color separation and light-guiding optical system 200 and the red light optical modulator 400R. A field lens 300G is disposed between the color separation and light-guiding optical system 200 and the green light optical modulator 400G. A field lens 300B is disposed between the color separation and light-guiding optical system 200 and the blue light optical modulator 400B. The field lens 300R collimates the chief ray of the red light LR incident on the red light optical modulator 400R. The field lens 300G collimates the chief ray of the green light LG incident on the green light optical modulator 400G. The field lens 300B collimates the chief ray of the blue light LB incident on the blue light optical modulator 400B.

[0016] The first dichroic mirror 210 transmits the red light LR and reflects the green light LG and blue light LB. The second dichroic mirror 220 reflects the green light LG and transmits the blue light LB. The first reflecting mirror 230 reflects the red light LR. The second reflecting mirror 240 and the third reflecting mirror 250 each reflect the blue light LB.

[0017] The red light optical modulator 400R, the green light optical modulator 400G, and the blue light optical modulator 400B each modulate the color light incident thereon in accordance with image information to generate image light. Each of the red light optical modulator 400R, the green light optical modulator 400G, and the blue light optical modulator 400B is composed of a liquid crystal panel.

[0018] Although not shown in the figure, incident-side polarizing plates are arranged between field lens 300R and red light optical modulator 400R, between field lens 300G and green light optical modulator 400G, and between field lens 300B and blue light optical modulator 400B. In addition, exit-side polarizing plates are arranged between red light optical modulator 400R and light combining element 500, between green light optical modulator 400G and light combining element 500, and between blue light optical modulator 400B and light combining element 500. The incident-side polarizing plate and the exit-side polarizing plate only transmit light linearly polarized in a specific direction.

[0019] The light combining element 500 receives the image lights emitted from the red light optical modulation device 400R, the green light optical modulation device 400G, and the blue light optical modulation device 400B, combines the image lights corresponding to the red light LR, the green light LG, and the blue light LB, and emits the combined image light toward the projection optical device 600. The light combining element 500 may be, for example, a cross dichroic prism.

[0020] The projection optical device 600 is composed of a plurality of projection lenses. The projection optical device 600 enlarges and projects the image light combined by the light combining element 500 onto the screen SCR, thereby displaying an image on the screen SCR.

[0021] The configurations of the light source device 30A and the illumination device 20 will be described below. Fig. 2 is a cross-sectional view of the light source device 30A of this embodiment, Fig. 3 is a cross-sectional view of the light source device 30A taken along line III-III in Fig. 2.

[0022] As shown in Figures 2 and 3, the light source device 30A of this embodiment includes a first light source 41, a wavelength conversion element 51, a first light guiding section 71, a second light guiding section 72, a first optical layer 61, a second light source 42, a collimating optical system 47, a second optical layer 62, and a reflective layer 65.

[0023] The first light source 41 has a third light source 43 and a fourth light source 44. The third light source 43 and the fourth light source 44 have the same configuration. Each of the third light source 43 and the fourth light source 44 has a plurality of light-emitting elements 411. The plurality of light-emitting elements 411 are mounted on a substrate 412. Note that the number of light-emitting elements 411 included in the first light source 41 is not particularly limited.

[0024] The light emitting element 411 emits excitation light rays in a first wavelength band. The light emitting element 411 is composed of a light emitting diode (LED). By configuring the light emitting element 411 with an LED, it is possible to reduce the cost of the light source device 30A and improve the light emitting efficiency. The light emitting element 411 is arranged opposite the wavelength conversion element 51 and emits excitation light rays toward the wavelength conversion element 51. The first wavelength band is, for example, a wavelength band from purple to blue of 400 nm to 480 nm. The center wavelength of the first wavelength band is, for example, 455 nm. The multiple light emitting elements 411 are arranged along the X-axis direction, which is the longitudinal direction of the wavelength conversion element 51.

[0025] The third light source 43 emits a plurality of blue excitation light beams toward the wavelength conversion element 51 via the first light guiding section 71. The fourth light source 44 is disposed opposite the third light source 43 across the wavelength conversion element 51, and emits a plurality of blue excitation light beams toward the wavelength conversion element 51 via the second light guiding section 72. In this way, the first light source 41 causes excitation light E of a first wavelength band consisting of a plurality of blue excitation light beams to be incident on the wavelength conversion element 51. The excitation light E in this embodiment corresponds to the first light in the claims.

[0026] The wavelength conversion element 51 has a plate-like shape extending along the X-axis and has six faces. The sides of the wavelength conversion element 51 extending along the X-axis are longer than the sides extending along the Y-axis and the Z-axis. The X-axis direction corresponds to the longitudinal direction of the wavelength conversion element 51. The Y-axis direction is a direction parallel to the shortest side of the wavelength conversion element 51. The length of the sides along the Y-axis is shorter than the length of the sides along the Z-axis. That is, the cross-sectional shape of the wavelength conversion element 51 cut along a plane along the YZ plane is rectangular, as shown in FIG. 3.

[0027] The wavelength conversion element 51 has a first end face 51a and a second end face 51b, a first side face 51c and a second side face 51d, a third side face 51e and a fourth side face 51f. The first end face 51a and the second end face 51b face opposite each other in the X-axis direction along the longitudinal direction of the wavelength conversion element 51. In this embodiment, the first end face 51a is located on the +X side, which is one side in the X-axis direction. The second end face 51b is located on the -X side, which is the other side in the X-axis direction. The first end face 51a of this embodiment corresponds to face 1 in the claims. The second end face 51b of this embodiment corresponds to face 2 in the claims.

[0028] The first side surface 51c and the second side surface 51d intersect the first end surface 51a and the second end surface 51b and face opposite each other along the Y axis. In this embodiment, the first side surface 51c is located on the +Y side, which is one side in the Y axis direction. The second side surface 51d is located on the -Y side, which is the other side in the Y axis direction. Excitation light E is incident on the first side surface 51c from the third light source 43 via the first light guiding section 71. Excitation light E is incident on the second side surface 51d from the fourth light source 44 via the second light guiding section 72. The first side surface 51c and the second side surface 51d in this embodiment correspond to the third side of the claims.

[0029] 3, the third side surface 51e and the fourth side surface 51f intersect with the first end surface 51a and the second end surface 51b, and with the first side surface 51c and the second side surface 51d, and face opposite each other in the Z axis direction. The third side surface 51e is located on one side, the +Z side, in the Z axis direction. The fourth side surface 51f is located on the other side, the -Z side, in the Z axis direction.

[0030] The wavelength conversion element 51 contains at least a yellow phosphor and converts the excitation light E in a first wavelength band emitted from the first light source 41 into yellow fluorescence Y in a second wavelength band different from the first wavelength band. As will be described in detail later, a portion of the yellow fluorescence Y generated inside the wavelength conversion element 51 is emitted from the first side surface 51c to the first light guiding section 71, and another portion of the yellow fluorescence Y is emitted from the second side surface 51d to the second light guiding section 72.

[0031] The wavelength conversion element 51 includes a ceramic phosphor made of a polycrystalline phosphor that converts the wavelength of the excitation light E into yellow fluorescence Y. The wavelength conversion element 51 of this embodiment is made of a phosphor with light scattering properties, a so-called scattering phosphor. The second wavelength band of the yellow fluorescence Y is, for example, a yellow wavelength band of 490 to 750 nm. The center wavelength of the second wavelength band is, for example, 550 nm. In other words, the fluorescence Y is yellow fluorescence containing a red light component and a green light component. The yellow fluorescence Y of this embodiment corresponds to the second light in the claims.

[0032] The wavelength conversion element 51 may contain a single crystal phosphor instead of a polycrystalline phosphor. Alternatively, the wavelength conversion element 51 may be made of fluorescent glass. Alternatively, the wavelength conversion element 51 may be made of a material in which a large number of phosphor particles are dispersed in a binder made of glass or resin. A wavelength conversion element 51 made of such a material converts blue excitation light E into yellow fluorescence Y.

[0033] Specifically, the material of the wavelength conversion element 51 includes, for example, an yttrium-aluminum-garnet (YAG) phosphor. Taking YAG:Ce containing cerium (Ce) as an activator as an example, the material of the wavelength conversion element 51 may be a material obtained by mixing raw material powders containing constituent elements such as Y2O3, Al2O3, and CeO3 and causing a solid-phase reaction, Y-Al-O amorphous particles obtained by a wet method such as a coprecipitation method or a sol-gel method, or YAG particles obtained by a gas-phase method such as a spray-drying method, a flame pyrolysis method, or a thermal plasma method.

[0034] The first optical layer 61 is disposed between the first light source 41 and the wavelength conversion element 51. That is, the first optical layer 61 is disposed between the third light source 43 and the wavelength conversion element 51, and between the fourth light source 44 and the wavelength conversion element 51. The first optical layer 61 has optical properties of transmitting the excitation light E and reflecting the yellow fluorescence Y. The first optical layer 61 is formed of, for example, a dielectric multilayer film. The first optical layer 61 is disposed on a second side surface 73d of a translucent member 73, which will be described later, facing the first light source 41.

[0035] The first light guiding section 71 and the second light guiding section 72 are disposed between the first optical layer 61 and the wavelength conversion element 51. That is, the first light guiding section 71 is disposed between the first optical layer 61 facing the third light source 43 and the first side surface 51c of the wavelength conversion element 51. The second light guiding section 72 is disposed between the first optical layer 61 facing the fourth light source 44 and the second side surface 51d of the wavelength conversion element 51. The first light guiding section 71 and the second light guiding section 72 have the same configuration.

[0036] The first light guiding section 71 and the second light guiding section 72 each guide the yellow fluorescence Y converted by the wavelength conversion element 51 and the blue light B emitted from the second light source 42. In this embodiment, the first light guiding section 71 and the second light guiding section 72 each include a light-transmitting member 73 that transmits the excitation light E, the yellow fluorescence Y, and the blue light B. The light-transmitting member 73 is a plate-shaped member, and is bonded to the first side surface 51c and the second side surface 51d of the wavelength conversion element 51 with an optical adhesive (not shown). The first light guiding section 71 and the second light guiding section 72 in this embodiment correspond to the light guiding section in the claims.

[0037] The light-transmitting member 73 is made of a light-transmitting material such as borosilicate glass (e.g., BK7), quartz, synthetic quartz, crystal, SiC, GaN, MgO, YAG, sapphire, or diamond. As described above, the light-transmitting member 73 must be made of a material that can transmit the excitation light E, yellow fluorescence Y, and blue light B. The light-transmitting member 73 has a plate-like shape extending along the X-axis. As shown in FIG. 3, the light-transmitting member 73 has a rectangular cross-section cut along the YZ plane and extends elongatedly in the X-axis direction. As shown in FIG. 2, of the two end faces of the light-transmitting member 73 that intersect with the X-axis, the end face on the side of the first end face 51a of the wavelength conversion element 51 is referred to as the first end face 73a, and the end face on the side of the second end face 51b of the wavelength conversion element 51 is referred to as the second end face 73b. Of the side surfaces of the light-transmitting member 73, the side surfaces in contact with the first side surface 51c and the second side surface 51d of the wavelength conversion element 51 are referred to as first side surfaces 73c, and the side surface opposite to the first side surface 73c is referred to as second side surface 73d. Note that the light-transmitting member 73 may have a shape other than a plate shape (rectangular parallelepiped).

[0038] It is desirable that the thermal conductivity of the light-transmitting member 73 be greater than that of the wavelength conversion element 51. Materials for the light-transmitting member 73 that satisfy this relationship include, for example, SiC, GaN, MgO, YAG, sapphire, and diamond. With this configuration, heat from the wavelength conversion element 51 is efficiently transferred to the light-transmitting member 73, thereby suppressing a temperature rise in the wavelength conversion element 51. This makes it possible to suppress a decrease in conversion efficiency due to a temperature rise in the wavelength conversion element 51.

[0039] The second light source 42 has a light-emitting element 421. The number of light-emitting elements 421 included in the second light source 42 is not particularly limited. The light-emitting element 421 emits blue light B in a third wavelength band different from the second wavelength band. The light-emitting element 421 is configured, for example, from a chip-shaped laser diode (LD). By configuring the light-emitting element 421 as an LD, which is a point light source, collimated light can be obtained using the collimating optical system 47. In this embodiment, the light-emitting element 421 is disposed opposite the second end surface 73b of the light-transmitting member 73 that configures the first light-guiding section 71.

[0040] The light-emitting element 421 emits blue light B in the third wavelength band toward at least the light-transmissive member 73. That is, the blue light B emitted from the light-emitting element 421 may be incident only on the light-transmissive member 73, or may be incident on both the light-transmissive member 73 and the wavelength conversion element 51. However, in this embodiment, for a simple explanation of the operation of the present invention, it is assumed that the blue light B emitted from the light-emitting element 421 is incident only on the light-transmissive member 73 of the first light guiding section 71. The ellipse indicated by the symbol B in FIG. 3 schematically shows the intensity distribution of the blue light B. Therefore, as shown in FIG. 2, the central axis B0 of the blue light B emitted from the light-emitting element 421 is shifted toward the +Y side with respect to the optical axis AX1. The third wavelength band is, for example, a blue wavelength band of 440 nm to 450 nm. The central wavelength of the third wavelength band is, for example, 445 nm.

[0041] Light-emitting element 421 is arranged so that the light-emitting surface of the laser diode chip faces the +X side, the longer side of the rectangular light-emitting surface faces the Y-axis direction, and the shorter side of the light-emitting surface faces the Z-axis direction. The central axis B0 of blue light B emitted from light-emitting element 421 is parallel to the X-axis. The divergence angle of blue light B differs in the Y-axis and Z-axis directions, with the divergence angle in the Z-axis direction being sufficiently larger than the divergence angle in the Y-axis direction. Therefore, the cross-sectional shape perpendicular to the central axis B0 of blue light B emitted from light-emitting element 421 is an elongated ellipse, with the major axis of the ellipse facing the Z-axis direction and the minor axis of the ellipse facing the Y-axis direction.

[0042] The collimating optical system 47 is disposed between the second light source 42 and the first light guiding unit 71. The collimating optical system 47 collimates the blue light B emitted from the second light source 42 and causes the light to enter the first light guiding unit 71. The collimating optical system 47 is composed of a collimator lens. The number of lenses constituting the collimating optical system 47 is not particularly limited, and the collimating optical system 47 may be composed of a plurality of lenses.

[0043] The second optical layer 62 is disposed on the −X side of the wavelength conversion element 51, the first light guiding section 71, and the second light guiding section 72. Specifically, the second optical layer 62 is disposed opposite the second end surface 51b of the wavelength conversion element 51 and the second end surface 73b of the light-transmitting member 73. The second optical layer 62 is composed of a dielectric multilayer film that transmits blue light and reflects yellow light. Therefore, the blue light B emitted from the second light source 42 passes through the collimating optical system 47, then passes through the second optical layer 62 and enters the first light guiding section 71. The yellow fluorescence Y, whose wavelength has been converted by the wavelength conversion element 51, propagates through the first light guiding section 71 and the second light guiding section 72 toward the −X side, and upon entering the second optical layer 62, is reflected by the second optical layer 62 and propagates through the first light guiding section 71 and the second light guiding section 72 toward the +X side.

[0044] As shown in FIG. 3 , the reflective layer 65 is disposed on both sides of the first light guiding section 71, the second light guiding section 72, and the wavelength conversion element 51 in the Z-axis direction. The reflective layer 65 reflects the excitation light E, the yellow fluorescence Y, and the blue light B. Therefore, the reflective layer 65 does not directly enter the wavelength conversion element 51, but reflects the excitation light E that enters the reflective layer 65 and makes it enter the wavelength conversion element 51. This improves the conversion efficiency of the excitation light E to the yellow fluorescence Y. The reflective layer 65 also reflects the yellow fluorescence Y and the blue light B that propagate through the first light guiding section 71 and the second light guiding section 72. This reduces the loss of the yellow fluorescence Y and the blue light B. The reflective layer 65 is formed of, for example, a metal film, a dielectric multilayer film, a scattering layer, or the like.

[0045] 1, an integrator optical system 90 is provided on the light emission side of the light source device 30A. The integrator optical system 90 has a first lens array 91 and a second lens array 92. The integrator optical system 90, together with a superimposing optical system 94, functions as a uniform illumination optical system that uniformizes the intensity distribution of the white light LW emitted from the light source device 30A in each of the light modulation devices 400R, 400G, and 400B, which are the illuminated areas. The white light LW emitted from the light source device 30A is incident on the first lens array 91.

[0046] The first lens array 91 has a plurality of first lenses 91a. The plurality of first lenses 91a are arranged in a matrix in a plane parallel to the YZ plane orthogonal to the optical axis AX1 of the illumination device 20. The plurality of first lenses 91a split the white light LW emitted from the light source device 30A into a plurality of partial light beams. The shape of each of the first lenses 91a is rectangular, which is approximately similar to the shape of the image formation areas of the light modulation devices 400R, 400G, and 400B. This allows each of the partial light beams emitted from the first lens array 91 to efficiently enter the image formation areas of the light modulation devices 400R, 400G, and 400B.

[0047] The white light LW emitted from the first lens array 91 travels toward the second lens array 92. The second lens array 92 is disposed opposite the first lens array 91. The second lens array 92 has a plurality of second lenses 92a corresponding to the plurality of first lenses 91a of the first lens array 91. The second lens array 92, together with the superimposing optical system 94, forms each of the images of the plurality of first lenses 91a of the first lens array 91 near the image forming areas of the light modulation devices 400R, 400G, and 400B. The plurality of second lenses 92a are arranged in a matrix in a plane parallel to the YZ plane that is perpendicular to the optical axis AX1 of the illumination device 20. The superimposing optical system 94 is composed of a single convex lens.

[0048] In this embodiment, the first lenses 91a of the first lens array 91 and the second lenses 92a of the second lens array 92 have the same size, but may have different sizes. Also, in this embodiment, the first lenses 91a of the first lens array 91 and the second lenses 92a of the second lens array 92 are arranged so that their optical axes coincide with each other, but they may be arranged eccentrically with each other.

[0049] The polarization conversion element 93 converts the polarization direction of the white light LW emitted from the second lens array 92. Specifically, the polarization conversion element 93 converts each partial beam of the white light LW split by the first lens array 91 and emitted from the second lens array 92 into linearly polarized light. The polarization conversion element 93 has a polarization separation layer (not shown), a reflection layer (not shown), and a phase difference layer (not shown). The polarization separation layer transmits one linearly polarized component of the polarization components contained in the white light LW emitted from the light source device 30A as is, and reflects the other linearly polarized component in a direction perpendicular to the optical axis AX1. The reflection layer reflects the other linearly polarized component reflected by the polarization separation layer in a direction parallel to the optical axis AX1. The phase difference layer converts the other linearly polarized component reflected by the reflection layer into one linearly polarized component.

[0050] The behavior of light in the light source device 30A of this embodiment will be described below. As shown in FIG. 2, in the light source device 30A, the excitation light E emitted from the first light source 41 passes through the first optical layer 61 and the light-transmitting member 73 and enters the wavelength conversion element 51.

[0051] When excitation light E is incident on the wavelength conversion element 51, the phosphor contained in the wavelength conversion element 51 is excited, and yellow fluorescence Y is emitted from any light-emitting point. At this time, the excitation light E incident on the phosphor is diffused and propagates over an area wider than the incident area, thereby expanding the width of the emission area of ​​the yellow fluorescence Y, resulting in so-called bleeding of the yellow fluorescence Y.

[0052] The yellow fluorescence Y that is incident from the light-emitting point of the wavelength conversion element 51 onto the first side surface 51c and the second side surface 51d at an incident angle less than the critical angle is emitted from the wavelength conversion element 51, enters the light-transmitting member 73, and propagates inside the light-transmitting member 73. At this time, the fluorescence Y traveling toward the +X side is reflected by the first optical layer 61 and re-enters the wavelength conversion element 51. In the present embodiment, since the wavelength conversion element 51 is made of a scattering phosphor, the yellow fluorescence Y is scattered inside the wavelength conversion element 51, is emitted again from the wavelength conversion element 51 to the light-transmitting member 73, propagates through the light-transmitting member 73, and then emitted to the outside from the first end surface 73a of the light-transmitting member 73.

[0053] Yellow fluorescence generated inside the wavelength conversion element 51 and incident on the first side surface 51c and the second side surface 51d of the wavelength conversion element 51 at an incident angle equal to or greater than the critical angle is once totally reflected by the first side surface 51c and the second side surface 51d of the wavelength conversion element 51. However, in the present embodiment, because the wavelength conversion element 51 is made of a scattering phosphor, the traveling direction of the yellow fluorescence Y changes inside the wavelength conversion element 51, and the incident angle of the yellow fluorescence Y on the first side surface 51c and the second side surface 51d of the wavelength conversion element 51 also changes. As a result, the yellow fluorescence Y is emitted from the wavelength conversion element 51 to the light-transmitting member 73, propagates through the light-transmitting member 73, and then emitted to the outside from the first end surface 73a of the light-transmitting member 73.

[0054] On the other hand, the yellow fluorescence Y that travels through the light-transmitting member 73 toward the -X side and reaches the second optical layer 62 is reflected by the second optical layer 62, travels toward the +X side, and follows the same path as the above-mentioned yellow fluorescence Y. That is, the yellow fluorescence Y propagates inside the light-transmitting member 73 or the wavelength conversion element 51 while repeatedly reflecting between the first optical layer 61 and the first side surface 51c or the second side surface 51d of the wavelength conversion element 51, and is emitted to the outside from the first end surface 73a of the light-transmitting member 73 or the first end surface 51a of the wavelength conversion element 51.

[0055] In contrast, blue light B emitted from the second light source 42 and collimated by the collimating optical system 47 passes through the second optical layer 62 and enters the light-transmitting member 73 of the first light guiding unit 71. At this time, the blue light B enters the second end face 73b of the light-transmitting member 73 perpendicularly, and therefore travels inside the light-transmitting member 73 in a direction parallel to the first side face 51c of the wavelength conversion element 51. Therefore, almost no blue light B enters the first side face 73c and the second side face 73d of the light-transmitting member 73, and is emitted to the outside from the first end face 73a of the light-transmitting member 73.

[0056] In this way, the light source device 30A can emit to the outside white light LW that is a combination of the yellow fluorescence Y emitted from the first end face 51a of the wavelength conversion element 51 and the first end face 73a of the light-transmitting member 73 and the blue light B emitted from the first end face 73a of the light-transmitting member 73. This makes it possible for the light source device 30A to reduce the etendue of the white light LW, thereby reducing loss of the white light LW in optical members such as the integrator optical system 90 that are arranged downstream of the light source device 30A. As a result, the utilization efficiency of the white light LW in the light source device 30A can be improved.

[0057] (Effects of the first embodiment) The light source device 30A of this embodiment includes: a first light source 41 that emits excitation light E; a wavelength conversion element 51 that converts the excitation light E into yellow fluorescence Y; a first optical layer 61 that is disposed between the first light source 41 and the wavelength conversion element 51 and that transmits the excitation light E and reflects the yellow fluorescence Y; a second light source 42 that emits blue light B; a first light guiding section 71 and a second light guiding section 72 that are disposed between the first optical layer 61 and the wavelength conversion element 51 and that guide the yellow fluorescence Y converted by the wavelength conversion element 51 and the blue light B emitted from the second light source 42; a collimating optical system 47 that is disposed between the second light source 42 and the first light guiding section 71 and that collimates the blue light B to cause it to enter the first light guiding section 71; and a second optical layer 62 that is disposed between the collimating optical system 47 and the first light guiding section 71 and that transmits the blue light B and reflects the yellow fluorescence Y. The wavelength conversion element 51 has a first end face 51a and a second end face 51b facing opposite to each other, and a first side face 51c and a second side face 51d intersecting the first end face 51a and the second end face 51b. Excitation light E emitted from the first light source 41 is incident on the first side face 51c and the second side face 51d of the wavelength conversion element 51 via the first optical layer 61. Yellow fluorescence Y converted by the wavelength conversion element 51 travels through the first light guiding section 71 and the second light guiding section 72 and is emitted from the first end faces 73a of the first light guiding section 71 and the second light guiding section 72. The blue light B emitted from the second light source 42 is collimated by the collimating optical system 47, passes through the second optical layer 62, and enters the second end face 73b of the first light guiding section 71, travels through the first light guiding section 71 in a direction parallel to the first side surface 51c, and is emitted from the first end face 73a of the first light guiding section 71.

[0058] In conventional light source devices, the blue LED constituting the second light source is positioned opposite the side of the transparent rod, and blue light enters from the side of the transparent rod. Therefore, most of the blue light enters the side of the transparent rod multiple times at angles of incidence smaller than the critical angle before reaching the end face of the transparent rod. This causes a problem of much of the blue light leaking out from the side of the transparent rod, reducing the efficiency of blue light utilization. Furthermore, the leakage of blue light causes an imbalance between the amount of yellow light and the amount of blue light, making it difficult to obtain the desired white light.

[0059] To address this issue, in the light source device 30A of the present embodiment, the blue light B emitted from the second light source 42 is collimated by the collimating optical system 47 and enters the second end surface 73b of the first light guiding unit 71. The blue light B then travels through the first light guiding unit 71 in a direction parallel to the first side surface 51c of the wavelength conversion element 51, and does not enter the second side surface 73d of the first light guiding unit 71, i.e., the side surface opposite to the side surface in contact with the wavelength conversion element 51. This prevents leakage of the blue light B from the first light guiding unit 71 and reduces a decrease in the utilization efficiency of the blue light B. Furthermore, the light source device 30A of the present embodiment can maintain a good balance between the amount of yellow fluorescence Y and the amount of blue light B, thereby obtaining the desired white light LW.

[0060] In the light source device 30A of this embodiment, the wavelength conversion element 51 has a first side surface 51c and a second side surface 51d facing opposite to each other, the light guiding section has a first light guiding section 71 arranged opposite to the first side surface 51c and a second light guiding section 72 arranged opposite to the second side surface 51d, and the first light source 41 has a third light source 43 that causes excitation light E to be incident on the wavelength conversion element 51 via the first light guiding section 71, and a fourth light source 44 that causes excitation light E to be incident on the wavelength conversion element 51 via the second light guiding section 72.

[0061] According to this configuration, the first side surface 51c and the second side surface 51d of the wavelength conversion element 51 are in contact with the light-transmitting member 73, so that heat from the wavelength conversion element 51 is efficiently transferred to the light-transmitting member 73, and a temperature rise in the wavelength conversion element 51 is suppressed. This makes it possible to suppress a decrease in wavelength conversion efficiency that accompanies a temperature rise in the wavelength conversion element 51. Furthermore, because the excitation light E emitted from each of the third light source 43 and the fourth light source 44 is incident on the wavelength conversion element 51 from the two side surfaces 51c, 51d, it is possible to ensure the amount of excitation light E and the amount of yellow fluorescence Y.

[0062] The projector 10 of this embodiment includes a light source device 30A, light modulation devices 400R, 400G, and 400B that modulate the light emitted from the light source device 30A, and a projection optical device 600 that projects the light modulated by the light modulation devices 400R, 400G, and 400B. According to this configuration, since the light source device 30A emits white light LW, there is no need to prepare a light source device that emits blue light separately from a light source device that emits yellow fluorescent light, and a projector 10 with a highly efficient and simple configuration can be realized.

[0063] [Second embodiment] A second embodiment of the present invention will be described below with reference to FIGS. The basic configuration of the light source device of the second embodiment is the same as that of the first embodiment, but the optical system at the front stage that causes blue light to enter the light guide section is different from that of the first embodiment, so a description of the basic configuration of the light source device will be omitted. Fig. 4 is a cross-sectional view of the light source device 30B of the second embodiment cut along the XY plane. Fig. 5 is a cross-sectional view of the wavelength conversion element and the light guide section cut along the YZ plane. In Fig. 4 and Fig. 5, the same reference numerals are used to designate components common to the drawings used in the first embodiment, and their description will be omitted.

[0064] As shown in Figures 4 and 5, the light source device 30B of this embodiment includes a first light source 41, a wavelength conversion element 51, a first light guiding section 71, a second light guiding section 72, a first optical layer 61, a second light source 82, a collimating optical system 83, a light combining element 84, the second optical layer 62, and a reflective layer 65.

[0065] In the light source device 30B of this embodiment, the second light source 82 has a first light emitting element 821 and a second light emitting element 822. The first light emitting element 821 and the second light emitting element 822 are configured with the same LD that emits blue light B. However, the polarization direction of the blue light B emitted from the first light emitting element 821 is different from the polarization direction of the blue light B emitted from the second light emitting element 822. Specifically, the blue light B emitted from the first light emitting element 821 is P-polarized with respect to a polarization separation film 842, which will be described later. The blue light B emitted from the second light emitting element 822 is S-polarized with respect to a polarization separation film 842, which will be described later. Therefore, when the chip orientations of the first light emitting element 821 and the second light emitting element 822 are the same, a half-wave plate (not shown) is provided on the light emission side of either the first light emitting element 821 or the second light emitting element 822. Alternatively, when no half-wave plate is provided, the first light-emitting element 821 and the second light-emitting element 822 are arranged such that the orientation of the chips is rotated 90 degrees around an axis perpendicular to the light-emitting surface.

[0066] The collimating optical system 83 is disposed on the light emission side of the second light source 82. The collimating optical system 83 has a first collimating element 831 and a second collimating element 832. Each of the first collimating element 831 and the second collimating element 832 is composed of a collimator lens. The first collimating element 831 is disposed on the light emission side of the first light-emitting element 821 and collimates the blue light B emitted from the first light-emitting element 821. The second collimating element 832 is disposed on the light emission side of the second light-emitting element 822 and collimates the blue light B emitted from the second light-emitting element 822.

[0067] The light combining element 84 is disposed on the light emission side of the collimating optical system 83. The light combining element 84 is composed of a polarization separation element (PBS) having a reflective film 841 and a polarization separation film 842. The P-polarized blue light B emitted from the first light-emitting element 821 is collimated by the first collimating element 831, then passes through the polarization separation film 842, and travels toward the second optical layer 62. The S-polarized blue light B emitted from the second light-emitting element 822 is collimated by the second collimating element 832, then reflected by the reflective film 841 and the polarization separation film 842, and travels toward the second optical layer 62. In this way, the light combining element 84 combines the P-polarized blue light B emitted from the first collimating element 831 and the S-polarized blue light B emitted from the second collimating element 832, and emits blue light B resulting from the combination of the P-polarized and S-polarized light. The blue light B combined by the light combining element 84 is also a parallel light.

[0068] 4, in this embodiment, the central axis of the blue light B emitted from the light combining element 84 is positioned on the optical axis AX1. Therefore, as shown in FIG. 5, the blue light B emitted from the light combining element 84 is incident on the light-transmissive member 73 of the first light guiding unit 71, the wavelength conversion element 51, and the light-transmissive member 73 of the second light guiding unit 72. The other configurations of the light source device 30B are similar to those of the light source device 30A of the first embodiment.

[0069] (Effects of the second embodiment) In the present embodiment, the collimated blue light B also propagates through the first light guiding section 71 and the second light guiding section 72 in a direction parallel to the first side surface 51c and the second side surface 51d of the wavelength conversion element 51. This provides the same effect as in the first embodiment, that is, it is possible to realize a light source device 30B that has high utilization efficiency of the blue light B and can efficiently emit desired white light LW.

[0070] In this embodiment, the second light source 82 has a first light-emitting element 821 and a second light-emitting element 822. The collimating optical system 83 has a first collimating element 831 that collimates the blue light B emitted from the first light-emitting element 821, and a second collimating element 832 that collimates the blue light B emitted from the second light-emitting element 822. The light source device 30B further includes a light combining element 84 that combines the blue light B emitted from the first collimating element 831 and the blue light B emitted from the second collimating element 832.

[0071] According to this configuration, the number of light-emitting elements constituting the second light source 82 is greater than in the first embodiment, and therefore the amount of blue light B can be increased. However, unlike the first embodiment, part of the blue light B emitted from the second light source 82 is incident on the wavelength conversion element 51 in addition to the first light guiding section 71 and the second light guiding section 72, and functions as excitation light. Therefore, the amount of yellow fluorescence Y can also be increased compared to the first embodiment. As a result, the overall amount of white light LW can be increased.

[0072] [Third embodiment] A third embodiment of the present invention will be described below with reference to FIGS. The basic configuration of the light source device of the third embodiment is the same as that of the first embodiment, but the upstream optical system that causes blue light to enter the light guide section is different from that of the first embodiment, so a description of the basic configuration of the light source device will be omitted. Fig. 6 is a cross-sectional view of a light source device 30C of the third embodiment cut along the XY plane. Fig. 7 is a cross-sectional view of a wavelength conversion element and a light guiding unit cut along the YZ plane. In Fig. 6 and Fig. 7, components common to those in the first embodiment are designated by the same reference numerals, and their description will be omitted.

[0073] As shown in Figures 6 and 7, the light source device 30C of this embodiment includes a first light source 41, a wavelength conversion element 51, a first light guiding section 71, a second light guiding section 72, a first optical layer 61, a second light source 82, a collimating optical system 83, an optical axis shift element 85, the second optical layer 62, and a reflective layer 65.

[0074] The configurations of the second light source 82 and the collimating optical system 83 are the same as those in the second embodiment. However, in this embodiment, the polarization direction of the blue light B emitted from the first light-emitting element 821 constituting the second light source 82 and the polarization direction of the blue light B emitted from the second light-emitting element 822 do not have to be different from each other.

[0075] The optical axis shift element 85 is provided on the light emission side of the second collimating element 832. The optical axis shift element 85 has a first mirror 851 and a second mirror 852. The first mirror 851 and the second mirror 852 each reflect the blue light B emitted from the second collimating element 832. The first mirror 851 is disposed on the +X side of the central axis of the blue light B emitted from the second collimating element 832. The second mirror 852 is disposed on the -Y side of the central axis of the blue light B emitted from the first mirror 851. Therefore, the blue light B emitted from the second collimating element 832 is reflected by the first mirror 851 and travels in the -Y side, and is reflected by the second mirror 852 and travels in the +X side toward the second optical layer 62.

[0076] The optical axis shift element 85 may be provided on the light emission side of the first collimating element 831 and shift the optical axis of the blue light B emitted from the first collimating element 831. In this way, the optical axis shift element 85 shifts the optical axis of at least one of the blue light B emitted from the first collimating element 831 and the blue light B emitted from the second collimating element 832 in a direction perpendicular to the first side surface 51c of the wavelength conversion element 51 (the Y-axis direction) and causes the light to be incident on the second end surfaces 73b of the first light guiding unit 71 and the second light guiding unit 72. In this embodiment, the optical axis of the blue light B emitted from the second collimating element 832 shifts to the -Y side along the Y-axis direction.

[0077] Furthermore, the second mirror 852 is movable in a direction (Y-axis direction) along the central axis of the blue light B emitted from the first mirror 851. This makes it possible to adjust the shift amount along the Y-axis direction of the optical axis of the blue light B emitted from the second collimating element 832. Therefore, by changing the position of the second mirror 852 in the Y-axis direction, it is possible to appropriately adjust the ratio between the blue light B incident on the first light guiding unit 71 and the blue light B incident on the wavelength conversion element 51, of the blue light B emitted from the second collimating element 832, as shown in FIG. The other configurations of the light source device 30C are similar to those of the light source device 30A of the first embodiment.

[0078] (Effects of the third embodiment) In the present embodiment as well, the collimated blue light B propagates through the first light guiding part 71 in a direction parallel to the first side surface 51c of the wavelength conversion element 51. This provides the same effect as in the first embodiment, that is, it is possible to realize a light source device 30C that has high utilization efficiency of the blue light B and can efficiently emit the desired white light LW.

[0079] The inventors' investigations revealed that when the light source device of this embodiment is realized using commercially available light-emitting elements such as LDs and LEDs, the amount of blue light becomes too large relative to the amount of yellow light, resulting in the emission of bluish white light. To address this issue, this embodiment, as described above, adjusts the position of the second mirror 852 of the optical axis shift element 85 to appropriately adjust the ratio of the blue light B incident on the first light guide unit 71 to the blue light B incident on the wavelength conversion element 51, among the blue light B emitted from the second collimating element 832. This optimizes the ratio between the amount of blue light B and the amount of yellow fluorescence Y, thereby enabling the production of desired white light LW. While the power supplied to the blue LD can be reduced to adjust the ratio between the amount of blue light B and the amount of yellow fluorescence Y, this method presents the problem of insufficient output from the blue LD. This embodiment eliminates the above problem by enabling the blue LD to be used at full power.

[0080] [Fourth embodiment] A fourth embodiment of the present invention will be described below with reference to FIGS. The basic configuration of the light source device of the fourth embodiment is the same as that of the first embodiment, but the upstream optical system that causes blue light to enter the light guide section is different from that of the first embodiment, so a description of the basic configuration of the light source device will be omitted. Fig. 8 is a cross-sectional view of a light source device 30D of the fourth embodiment cut along the XY plane. Fig. 9 is a cross-sectional view of a wavelength conversion element and a light guiding unit cut along the YZ plane. In Fig. 8 and Fig. 9, components common to those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0081] As shown in Figures 8 and 9, the light source device 30D of this embodiment includes a first light source 41, a wavelength conversion element 51, a first light guiding section 71, a second light guiding section 72, a first optical layer 61, a second light source 82, a collimating optical system 83, a light combining element 84, the second optical layer 62, and a reflective layer 65.

[0082] The configurations of the second light source 82, the collimating optical system 83, and the light combining element 84 are the same as those in the second embodiment. However, in the case of the present embodiment, the second light source 82, the collimating optical system 83, and the light combining element 84 are rotatable by a predetermined angle around a virtual axis extending in a direction (X-axis direction) perpendicular to the first end face 51a and the second end face 51b of the wavelength conversion element 51. In the present embodiment, the second light source 82 may have one or more light-emitting elements.

[0083] 9, it is possible to appropriately adjust the ratio of the blue light B incident on the first light guiding section 71 and the second light guiding section 72 (light-transmitting member 73) to the blue light B incident on the wavelength conversion element 51. That is, if the angle α formed by the Z axis and the major axis of an ellipse, which is the cross-sectional shape of the blue light B perpendicular to the central axis, is defined as the rotation angle, the larger the rotation angle α, the more blue light B incident on the light-transmitting member 73 becomes, and the more blue light B incident on the wavelength conversion element 51 becomes. The smaller the rotation angle α, the more blue light B incident on the light-transmitting member 73 becomes, and the more blue light B incident on the wavelength conversion element 51 becomes. The other configurations of the light source device 30D are similar to those of the light source device 30A of the first embodiment.

[0084] (Effects of the fourth embodiment) In the present embodiment as well, the collimated blue light B propagates through the first light guiding section 71 and the second light guiding section 72 in a direction parallel to the first side surface 51c and the second side surface 51d of the wavelength conversion element 51. This provides the same effect as in the first embodiment, that is, it is possible to realize a light source device 30D that has high utilization efficiency of the blue light B and can efficiently emit desired white light LW.

[0085] According to this embodiment, as described above, by changing the rotation angle α of the second light source 82, the collimating optical system 83, and the light combining element 84, it is possible to appropriately adjust the ratio of the blue light B incident on the first light guiding unit 71 and the second light guiding unit 72 to the blue light B incident on the wavelength conversion element 51. This makes it possible to optimize the ratio between the amount of blue light B and the amount of yellow fluorescence Y, thereby obtaining the desired white light LW.

[0086] [Fifth embodiment] Hereinafter, a fifth embodiment of the present invention will be described with reference to FIG. The basic configuration of the light source device of the fifth embodiment is the same as that of the first embodiment, but the configuration of the light guide section is different from that of the first embodiment, so a description of the basic configuration of the light source device will be omitted. Fig. 10 is a cross-sectional view of a light source device 30E of the fifth embodiment cut along the XY plane. In Fig. 10, components common to those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0087] As shown in FIG. 10, the light source device 30E of this embodiment includes a first light source 41, a wavelength conversion element 51, a first light guiding section 75, a second light guiding section 76, a first optical layer 61, a second light source 42, a collimating optical system 47, a second optical layer 62, and a reflective layer (not shown).

[0088] In the light source device 30A of the first embodiment, the first light guiding section 71 and the second light guiding section 72 are formed of a light-transmitting member 73. In contrast, in the light source device 30E of the present embodiment, the first light guiding section 75 and the second light guiding section 76 are formed of an air layer 77. That is, the first optical layer 61 and the wavelength conversion element 51 are disposed apart from each other, and air exists between the first optical layer 61 and the wavelength conversion element 51. Therefore, the yellow fluorescence Y converted by the wavelength conversion element 51 and the blue light B emitted from the second light source 42 are emitted from the region of the air layer 77 on the first end surface 51 a side. The other configurations of the light source device 30E are similar to those of the light source device 30A of the first embodiment.

[0089] (Effects of the fifth embodiment) In the present embodiment as well, the collimated blue light B propagates through the first light guiding part 75 in a direction parallel to the first side surface 51c of the wavelength conversion element 51. This provides the same effect as in the first embodiment, that is, it is possible to realize a light source device 30E that has high utilization efficiency of the blue light B and can efficiently emit the desired white light LW.

[0090] In this embodiment, the first light guiding section 75 and the second light guiding section 76 are formed with an air layer 77. This increases the difference in refractive index between the wavelength conversion element 51 and each light guiding section 75, 76 compared to when the first light guiding section and the second light guiding section are formed with a translucent material such as quartz. Therefore, the refraction angle of the fluorescence Y when it is emitted from the wavelength conversion element 51 to each light guiding section 75, 76 increases, and the fluorescence Y travels in a direction that forms a small angle with respect to the first side surface 51c and the second side surface 51d of the wavelength conversion element 51, i.e., a small angle with respect to the X-axis. Furthermore, because the regions of the first end surfaces 51a of each light guiding section 75, 76 are open to the external space and do not have a refractive index interface, the fluorescence Y that reaches the regions of the first end surfaces 51a of each light guiding section 75, 76 is emitted directly into the external space without reflection or refraction. As a result, the light source device 30E of this embodiment can improve the extraction efficiency of yellow fluorescence Y compared to the first embodiment.

[0091] [Sixth embodiment] A sixth embodiment of the present invention will be described below with reference to FIG. The basic configuration of the light source device of the sixth embodiment is the same as that of the first embodiment, but the arrangement of the light guide section and the wavelength conversion element is different from that of the first embodiment, so a description of the basic configuration of the light source device will be omitted. 11 is a cross-sectional view of a light source device 30F of the sixth embodiment cut along the XY plane. In Fig. 11, components common to those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0092] As shown in FIG. 11, the light source device 30F of this embodiment includes a first light source 41, a first wavelength conversion element 511, a second wavelength conversion element 512, a light guide section 70, a first optical layer 61, a second light source 42, a collimating optical system 47, a second optical layer 62, and a reflective layer (not shown).

[0093] The light source device 30F of this embodiment includes two wavelength conversion elements: a first wavelength conversion element 511 and a second wavelength conversion element 512. The first wavelength conversion element 511 and the second wavelength conversion element 512 have the same configuration and are arranged spaced apart from each other in the Y-axis direction. The first wavelength conversion element 511 and the second wavelength conversion element 512 each convert the excitation light E emitted from the first light source 41 into yellow fluorescence Y. The excitation light E emitted from the third light source 43 is incident on the first wavelength conversion element 511. The excitation light E emitted from the fourth light source 44 is incident on the second wavelength conversion element 512.

[0094] The light guiding unit 70 is composed of a plate-shaped light-transmitting member 73 made of quartz or the like. The first wavelength conversion element 511 and the second wavelength conversion element 512 are bonded to two side surfaces 73c, 73d of the light-transmitting member 73 with an optical adhesive. The yellow fluorescence Y converted by the first wavelength conversion element 511 and the second wavelength conversion element 512 is emitted from each wavelength conversion element 511, 512, travels inside the light guiding unit 70, and is emitted to the outside from a first end surface 70a of the light guiding unit 70. The other configurations of the light source device 30F are similar to those of the light source device 30A of the first embodiment.

[0095] (Effects of the sixth embodiment) In the present embodiment as well, the collimated blue light B propagates through the light-guiding unit 70 in a direction parallel to each side surface of each of the wavelength conversion elements 511 and 512. This provides the same effect as in the first embodiment, that is, it is possible to realize a light source device 30F that has high utilization efficiency of the blue light B and can efficiently emit desired white light LW.

[0096] [Seventh embodiment] The seventh embodiment of the present invention will be described below with reference to FIG. The basic configuration of the light source device of the seventh embodiment is the same as that of the first embodiment, but differs from the first embodiment in that a light diffusion element is added, so a description of the basic configuration of the light source device will be omitted. Fig. 12 is a cross-sectional view of a light source device 30G of the seventh embodiment cut along the XY plane. In Fig. 12, components common to those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0097] As shown in Figure 12, the light source device 30G of this embodiment includes a first light source 41, a wavelength conversion element 51, a first light guiding section 71, a second light guiding section 72, a first optical layer 61, a second light source 42, a collimating optical system 47, a second optical layer 62, a light diffusing element 89, and a reflective layer (not shown).

[0098] The light diffusion element 89 is disposed on the first end surface 73a of the light-transmitting member 73 that constitutes the first light guide section 71 and the second light guide section 72. Specifically, the light diffusion element 89 is bonded to the first end surface 73a of the light-transmitting member 73 with an optical adhesive. The light diffusion element 89 may be made of frosted glass having a random uneven structure. Alternatively, the light diffusion element 89 may be made of a microlens array diffuser plate having a regular uneven structure. The light diffusion element 89 diffuses blue light B emitted from the first end surface 73a of the light-transmitting member 73. The light diffusion element 89 of this embodiment corresponds to the light diffusion portion in the claims. Note that the light diffusion portion may be formed by directly unevenly processing the first end surface 73a of the light-transmitting member 73. The other configurations of the light source device 30G are similar to those of the light source device 30A of the first embodiment.

[0099] (Effects of the Seventh Embodiment) In the present embodiment as well, the collimated blue light B propagates through the first light guiding part 71 in a direction parallel to the first side surface 51c of the wavelength conversion element 51. This provides the same effect as in the first embodiment, that is, it is possible to realize a light source device 30G that has high utilization efficiency of the blue light B and can efficiently emit the desired white light LW.

[0100] Because the blue light B propagating through the first light guide unit 71 is collimated light from the LD point light source, it has a narrow divergence angle and a narrow peak when it exits the first end surface 73a of the translucent member 73. On the other hand, the fluorescence Y exiting the wavelength conversion element 51 has a wide divergence angle and a Lambertian luminous intensity distribution. Therefore, the white light LW obtained by combining the blue light B and the yellow fluorescence Y may cause color unevenness in the downstream optical system due to the difference in the luminous intensity distribution between the blue light and the yellow light. In contrast, the light source device 30G of this embodiment includes a light diffusion element 89 on the first end surface 73a of the translucent member 73. The blue light B is diffused by the light diffusion element 89 and exits the light source. This allows the luminous intensity distribution of the blue light B to approach that of the yellow fluorescence Y, thereby reducing color unevenness in the downstream optical system.

[0101] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, the first light source is disposed facing both the first side surface and the second side surface of the wavelength conversion element, and excitation light is incident from both the first side surface and the second side surface. However, instead of this configuration, the first light source may be disposed facing only one of the first side surface and the second side surface of the wavelength conversion element, and excitation light may be incident from one side surface. In this case, a heat conductive member such as a housing may be brought into contact with the side surface on which the excitation light is not incident. This allows heat from the wavelength conversion element to be efficiently dissipated.

[0102] In addition, the specific descriptions of the shape, number, arrangement, materials, etc. of each component of the light source device and the projector are not limited to the above-described embodiments and can be modified as appropriate. Furthermore, in the above-described embodiments, an example was shown in which the light source device according to the present invention was mounted in a projector using a liquid crystal panel, but this is not limiting. The light source device according to the present invention may also be applied to a projector using a digital micromirror device as a light modulation device. Furthermore, the projector does not need to have multiple light modulation devices, and may have only one light modulation device.

[0103] In the above embodiment, the light source device of the present invention is applied to a projector, but the present invention is not limited to this. The light source device of the present invention can also be applied to lighting fixtures, automobile headlights, and the like.

[0104] Summary of this disclosure A summary of this disclosure is provided below.

[0105] (Appendix 1) a first light source that emits first light in a first wavelength band; a wavelength conversion element that converts the first light into second light in a second wavelength band different from the first wavelength band; a first optical layer disposed between the first light source and the wavelength conversion element, the first optical layer transmitting the first light and reflecting the second light; a second light source that emits third light in a third wavelength band different from the second wavelength band; a light guiding section disposed between the first optical layer and the wavelength conversion element, which guides the second light converted by the wavelength conversion element and the third light emitted from the second light source; a collimating optical system disposed between the second light source and the light guiding unit, which collimates the third light and causes the third light to enter the light guiding unit; a second optical layer disposed between the collimating optical system and the light guiding unit, the second optical layer transmitting the third light and reflecting the second light; Equipped with the wavelength conversion element has a first surface and a second surface facing opposite to each other, and a third surface intersecting the first surface and the second surface; the first light emitted from the first light source is incident on the third surface of the wavelength conversion element via the first optical layer, the second light converted by the wavelength conversion element travels through the light guiding section and is emitted from a region on the first surface side of the light guiding section, the third light emitted from the second light source is collimated by the collimating optical system, enters the region on the second surface side of the light guiding section through the second optical layer, travels through the light guiding section in a direction parallel to the third surface, and is emitted from the region on the first surface side of the light guiding section.

[0106] According to the configuration of Supplementary Note 1, the third light collimated by the collimating optical system travels inside the light guiding unit in a direction parallel to the third surface of the wavelength conversion element, thereby suppressing leakage of the third light from the light guiding unit and realizing a light source device with high utilization efficiency of the third light.

[0107] (Appendix 2) the light guide portion has a light-transmitting member that transmits the first light, the second light, and the third light, The light source device according to claim 1, wherein the second light converted by the wavelength conversion element and the third light emitted from the second light source are emitted from an end face of the translucent member on the first surface side.

[0108] According to the configuration of Supplementary Note 2, the combined light of the second light and the third light can be extracted to the outside through the light-transmitting member constituting the light-guiding section. In addition, since the heat of the wavelength conversion element is transferred to the light-transmitting member, it is possible to suppress a temperature rise of the wavelength conversion element and a decrease in wavelength conversion efficiency.

[0109] (Appendix 3) the light guide portion has an air layer, 2. The light source device according to claim 1, wherein the second light converted by the wavelength conversion element and the third light emitted from the second light source are emitted from a region on the first surface side of the air layer.

[0110] According to the configuration of Supplementary Note 3, the combined light of the second light and the third light can be extracted to the outside through the air layer that constitutes the light-guiding section. In addition, since the area on the first surface side of the air layer is open to the outside space, there is no refraction or reflection at the end face, and the extraction efficiency of the combined light can be increased.

[0111] (Appendix 4) the third surface of the wavelength conversion element has a first side surface and a second side surface facing in opposite directions, the light guiding section includes a first light guiding section disposed opposite the first side surface and a second light guiding section disposed opposite the second side surface, The light source device according to any one of Supplementary Note 1 to Supplementary Note 3, wherein the first light source includes a third light source that causes the first light to be incident on the wavelength conversion element via the first light guiding section, and a fourth light source that causes the first light to be incident on the wavelength conversion element via the second light guiding section.

[0112] According to the configuration of Supplementary Note 4, the amount of the first light incident on the wavelength conversion element can be increased, and therefore the amount of the second light can be increased.

[0113] (Appendix 5) the wavelength conversion element includes a first wavelength conversion element that converts the first light into the second light, and a second wavelength conversion element that converts the first light into the second light, the light guiding portion is disposed between the first wavelength conversion element and the second wavelength conversion element, The light source device according to any one of claims 1 to 3, wherein the first light source includes a third light source that causes the first light to be incident on the first wavelength conversion element and a fourth light source that causes the first light to be incident on the second wavelength conversion element.

[0114] According to the configuration of Supplementary Note 5, the amount of the first light incident on the wavelength conversion element can be increased, and therefore the amount of the second light can be increased.

[0115] (Appendix 6) the first light is blue light; the second light is yellow light containing a green light component and a red light component, 6. The light source device according to claim 1, wherein the third light is blue light.

[0116] According to the configuration of Supplementary Note 6, a light source device capable of efficiently emitting white light can be realized.

[0117] (Appendix 7) 7. The light source device according to claim 1, wherein the second light source has a laser diode that emits the third light.

[0118] According to the configuration of Supplementary Note 7, by configuring the light emitting element as a laser diode, which is a point light source, it is possible to obtain parallel light using a collimating optical system.

[0119] (Appendix 8) 8. The light source device according to claim 7, further comprising a light diffusion section disposed in a region on the first surface side of the light guide section, the light diffusion section diffusing the third light.

[0120] According to the configuration of Supplementary Note 8, even when a laser diode is used, the light distribution of the third light can be widened and made closer to the light distribution of the second light, thereby reducing color unevenness in the downstream optical system.

[0121] (Appendix 9) 9. The light source device according to claim 7, wherein the first light source has a light emitting diode that emits the first light.

[0122] According to the configuration of Supplementary Note 9, it is possible to reduce the cost of the light source device and improve the light emission efficiency.

[0123] (Appendix 10) the second light source includes a first light-emitting element that emits the third light and a second light-emitting element that emits the third light, the collimating optical system includes a first collimating element that collimates the third light emitted from the first light-emitting element, and a second collimating element that collimates the third light emitted from the second light-emitting element, The light source device according to any one of claims 1 to 9, further comprising a light combining element that combines the third light emitted from the first parallelizing element and the third light emitted from the second parallelizing element.

[0124] According to the configuration of Supplementary Note 10, the amount of the third light can be increased, and the amount of the combined light of the second light and the third light can be increased as a whole.

[0125] (Appendix 11) the second light source includes a first light-emitting element that emits the third light and a second light-emitting element that emits the third light; the collimating optical system includes a first collimating element that collimates the third light emitted from the first light-emitting element and a second collimating element that collimates the third light emitted from the second light-emitting element; and the light source device further includes an optical axis shift element that shifts the optical axis of at least one of the third light emitted from the first collimating element and the third light emitted from the second collimating element in a direction perpendicular to the third surface to cause the third light to enter a region on the second surface side of the light-guiding section; and a portion of the third light emitted from the first light-emitting element and the second light-emitting element is incident on the wavelength conversion element and converted into the second light.

[0126] According to the configuration of Supplementary Note 11, by changing the shift amount of the optical axis by the optical axis shift element, it is possible to appropriately adjust the ratio of the third light emitted from the second light source, which is incident on the light guiding section, to the third light which is incident on the wavelength conversion element, thereby making it possible to adjust the color of the combined light of the second light and the third light.

[0127] (Appendix 12) The light source device of any one of Supplementary Note 1 to Supplementary Note 9, wherein the second light source has a first light-emitting element that emits the third light, the collimating optical system has a first collimating element that collimates the third light emitted from the first light-emitting element, the second light source and the collimating optical system are rotatable around a virtual axis extending in a direction perpendicular to the first surface, and a portion of the third light emitted from the first light-emitting element is incident on the wavelength conversion element and converted into the second light.

[0128] According to the configuration of Supplementary Note 12, by changing the rotation angles of the second light source and the collimating optical system, it is possible to appropriately adjust the ratio of the third light incident on the light guide section and the third light incident on the wavelength conversion element, among the third light emitted from the second light source, thereby adjusting the color of the combined light of the second light and the third light.

[0129] (Appendix 13) A light source device according to any one of Supplementary Note 1 to Supplementary Note 12; a light modulation device that modulates the light emitted from the light source device; a projection optical device that projects the light modulated by the light modulation device; A projector equipped with

[0130] According to the configuration of Appendix 13, the light source device emits a combined light that is a combination of the second light and the third light, so that only one light source device is required, making it possible to realize a projector that is highly efficient and has a simple configuration. [Explanation of symbols]

[0131] 10...Projector, 30A, 30B, 30C, 30D, 30E, 30F, 30G...Light source device, 41...First light source, 42, 82...Second light source, 43...Third light source, 44...Fourth light source, 47, 83...Collimation optical system, 51...Wavelength conversion element, 51a...First end face (first surface), 51b...Second end face (second surface), 51c...First side face (third surface), 51d...Second side face (third surface), 61...First optical layer, 62...Second optical layer, 70...Light guide section, 71, 75...First Light guiding section, 72, 76...second light guiding section, 73...light-transmitting member, 77...air layer, 84...light combining element, 85...optical axis shift element, 511...first wavelength conversion element, 512...second wavelength conversion element, 821...first light-emitting element, 822...second light-emitting element, 831...first parallelizing element, 832...second parallelizing element, 400B, 400G, 400R...light modulation device, 600...projection optical device, E...excitation light (first light), Y...yellow fluorescence (second light), B...blue light (third light).

Claims

1. a first light source that emits first light in a first wavelength band; a wavelength conversion element that converts the first light into second light in a second wavelength band different from the first wavelength band; a first optical layer disposed between the first light source and the wavelength conversion element, the first optical layer transmitting the first light and reflecting the second light; a second light source that emits third light in a third wavelength band different from the second wavelength band; a light guiding section disposed between the first optical layer and the wavelength conversion element, which guides the second light converted by the wavelength conversion element and the third light emitted from the second light source; a collimating optical system disposed between the second light source and the light guiding unit, which collimates the third light and causes the third light to enter the light guiding unit; a second optical layer disposed between the collimating optical system and the light guiding unit, the second optical layer transmitting the third light and reflecting the second light; Equipped with the wavelength conversion element has a first surface and a second surface facing opposite to each other, and a third surface intersecting the first surface and the second surface; the first light emitted from the first light source is incident on the third surface of the wavelength conversion element via the first optical layer, the second light converted by the wavelength conversion element travels through the light guiding section and is emitted from a region on the first surface side of the light guiding section, the third light emitted from the second light source is collimated by the collimating optical system, enters the region on the second surface side of the light guiding section through the second optical layer, travels through the light guiding section in a direction parallel to the third surface, and is emitted from the region on the first surface side of the light guiding section.

2. the light guide portion has a light-transmitting member that transmits the first light, the second light, and the third light, The light source device according to claim 1 , wherein the second light converted by the wavelength conversion element and the third light emitted from the second light source are emitted from an end face of the translucent member on the first surface side.

3. the light guide portion has an air layer, The light source device according to claim 1 , wherein the second light converted by the wavelength conversion element and the third light emitted from the second light source are emitted from a region of the air layer on the first surface side.

4. the third surface of the wavelength conversion element has a first side surface and a second side surface facing opposite to each other, the light guiding section includes a first light guiding section disposed opposite the first side surface and a second light guiding section disposed opposite the second side surface, 3. The light source device according to claim 1, wherein the first light source includes a third light source that causes the first light to be incident on the wavelength conversion element via the first light guiding section, and a fourth light source that causes the first light to be incident on the wavelength conversion element via the second light guiding section.

5. the wavelength conversion element includes a first wavelength conversion element that converts the first light into the second light, and a second wavelength conversion element that converts the first light into the second light, the light guiding portion is disposed between the first wavelength conversion element and the second wavelength conversion element, 3. The light source device according to claim 1, wherein the first light source includes a third light source that causes the first light to be incident on the first wavelength conversion element, and a fourth light source that causes the first light to be incident on the second wavelength conversion element.

6. the first light is blue light, the second light is yellow light containing a green light component and a red light component, The light source device according to claim 1 , wherein the third light is blue light.

7. 3. The light source device according to claim 1, wherein the second light source has a laser diode that emits the third light.

8. The light source device according to claim 7 , further comprising a light diffusion section arranged in a region on the first surface side of the light guide section, the light diffusion section diffusing the third light.

9. The light source device according to claim 7 , wherein the first light source has a light emitting diode that emits the first light.

10. the second light source includes a first light-emitting element that emits the third light and a second light-emitting element that emits the third light, the collimating optical system includes a first collimating element that collimates the third light emitted from the first light-emitting element and a second collimating element that collimates the third light emitted from the second light-emitting element, 3. The light source device according to claim 1, further comprising a light combining element that combines the third light emitted from the first collimating element and the third light emitted from the second collimating element.

11. the second light source includes a first light-emitting element that emits the third light and a second light-emitting element that emits the third light, the collimating optical system includes a first collimating element that collimates the third light emitted from the first light-emitting element and a second collimating element that collimates the third light emitted from the second light-emitting element, an optical axis shift element that shifts an optical axis of at least one of the third light emitted from the first collimating element and the third light emitted from the second collimating element in a direction perpendicular to the third surface and causes the third light to enter a region on the second surface side of the light guiding unit, 3. The light source device according to claim 1, wherein a part of the third light emitted from the first light emitting element and the second light emitting element is incident on the wavelength conversion element and converted into the second light.

12. the second light source has a first light-emitting element that emits the third light, the collimating optical system includes a first collimating element that collimates the third light emitted from the first light-emitting element, the second light source and the collimating optical system are rotatable about a virtual axis extending in a direction perpendicular to the first surface, 3. The light source device according to claim 1, wherein a part of the third light emitted from the first light emitting element is incident on the wavelength conversion element and converted into the second light.

13. The light source device according to claim 1 or 2; a light modulation device that modulates the light emitted from the light source device; a projection optical device that projects the light modulated by the light modulation device; A projector equipped with

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