Light source device and projector

Abstract

To provide a light source device with high light utilization efficiency. [Solution] The light source device of the present invention comprises a light source unit that emits first light in a first wavelength band, a wavelength conversion layer that converts the first light into second light in a second wavelength band, and a translucent substrate having a first surface and a second surface, with the wavelength conversion layer provided on the first surface. The first light emitted from the light source unit is incident on the translucent substrate from the second surface, passes through the translucent substrate, and is incident on the wavelength conversion layer from the first surface. A portion of the second light converted in the wavelength conversion layer is incident on the translucent substrate from the first surface. The light source device has a first reflective surface that intersects the first and second surfaces of the translucent substrate and reflects the second light.

Description

Technical Field

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

Background Art

[0002] As a light source device used in a projector, a light source device that uses fluorescence emitted when excitation light emitted from a light-emitting element irradiates a phosphor has been proposed. Patent Document 1 below discloses a light source device that generates illumination light including fluorescence and a part of the excitation light by making the excitation light enter a phosphor layer formed on a transparent substrate. In this light source device, the excitation light emitted from the excitation light source sequentially passes through the transparent substrate and the dichroic layer and then enters the phosphor layer. Among the fluorescence emitted from the phosphor layer in all directions, the fluorescence traveling toward the transparent substrate side is reflected by the dichroic layer and taken out to the side opposite to the transparent substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the light source device of Patent Document 1, in order to take out fluorescence in a desired direction, that is, to the side opposite to the transparent substrate, a dichroic layer that transmits excitation light and reflects fluorescence is provided between the transparent substrate and the phosphor layer. However, due to the optical characteristics of the dichroic layer, among the fluorescence incident on the dichroic layer, a part of the fluorescence passes through the dichroic layer and leaks into the transparent substrate. The fluorescence leaked into the transparent substrate may be emitted to the outside from the side surface of the transparent substrate after propagating while undergoing total reflection inside the transparent substrate. This fluorescence is difficult to be used as illumination light, resulting in a problem that the utilization efficiency of the fluorescence decreases.

Means for Solving the Problems

[0005] To solve the above problems, a light source device according to one aspect of the present invention comprises a light source unit that emits first light in a first wavelength band, a wavelength conversion layer that converts the first light into second light in a second wavelength band different from the first wavelength band, and a translucent substrate having a first surface and a second surface opposite to the first surface, with the wavelength conversion layer provided on the first surface. The first light emitted from the light source unit is incident on the translucent substrate from the second surface, passes through the translucent substrate, and is incident on the wavelength conversion layer from the first surface. A portion of the second light converted in the wavelength conversion layer is incident on the translucent substrate from the first surface. The light source device has a first reflective surface that intersects the first surface and the second surface of the translucent substrate and reflects the second light.

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

[0007] [Figure 1] This is a schematic diagram of the projector according to the first embodiment. [Figure 2] This is a schematic diagram of the light source device according to the first embodiment. [Figure 3] This is a front view of the wavelength conversion device. [Figure 4] This is a cross-sectional view of the wavelength conversion section along the IV-IV line in Figure 3. [Figure 5] This diagram shows the problems with conventional light source devices. [Figure 6] This is a cross-sectional view of the wavelength conversion section in the light source device of the second embodiment. [Figure 7] This is a cross-sectional view of the wavelength conversion section in the light source device of the third embodiment. [Modes for carrying out the invention]

[0008] [First Embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. Please note that the drawings used in the following explanation may be enlarged for convenience to clearly illustrate the features, and the dimensional ratios of each component may be modified as appropriate.

[0009] Figure 1 is a schematic diagram of the projector according to this embodiment. As shown in Figure 1, the projector 10 of this embodiment is a projection-type image display device that displays images on a screen SCR. The projector 10 comprises a light source device 100, a color separation optical system 200, an optical modulator 400R, an optical modulator 400G, an optical modulator 400B, a composite optical system 500, and a projection optical device 600. In the following description, the axis along the left-right direction of the projector is defined as the X-axis, the axis along the front-back direction of the projector is defined as the Y-axis, and the axis along the up-down direction of the projector, perpendicular to the X-axis and Y-axis, is defined as the Z-axis.

[0010] The light source device 100 emits white illumination light LW toward the color separation optical system 200. The configuration of the light source device 100 will be described in detail later.

[0011] The color separation optical system 200 separates the illumination light LW emitted from the light source device 100 into red light LR, green light LG, and blue light LB. The color separation optical system 200 includes a first dichroic mirror 210, a second dichroic mirror 220, a first reflective mirror 230, a second reflective mirror 240, a third reflective mirror 250, a first relay lens 260, and a second relay lens 270.

[0012] The first dichroic mirror 210 transmits red light LR and reflects light including green light LG and blue light LB. Thus, the first dichroic mirror 210 separates the illumination light LW emitted from the light source device 100 into red light LR and light including green light LG and blue light LB. The second dichroic mirror 220 reflects green light LG and transmits blue light LB. Thus, the second dichroic mirror 220 separates the light including green light LG and blue light LB emitted from the first dichroic mirror 210 into green light LG and blue light LB.

[0013] The first reflective mirror 230 is positioned in the optical path of red light LR and reflects the red light LR that has passed through the first dichroic mirror 210 toward the optical modulator 400R. The second reflective mirror 240 and the third reflective mirror 250 are positioned in the optical path of blue light LB and guide the blue light LB that has passed through the second dichroic mirror 220 toward the optical modulator 400B. The green light LG is reflected from the second dichroic mirror 220 toward the optical modulator 400G.

[0014] The first relay lens 260 is positioned between the second dichroic mirror 220 and the second reflective mirror 240 in the optical path of the blue light LB. The second relay lens 270 is positioned between the second reflective mirror 240 and the third reflective mirror 250 in the optical path of the blue light LB. The first relay lens 260 and the second relay lens 270 compensate for the optical loss of the blue light LB, which is caused by the blue light LB's optical path length being longer than that of the red light LR and green light LG.

[0015] The light modulation device 400R modulates the red light LR according to the image information and forms image light corresponding to the red light LR. The light modulation device 400G modulates the green light LG according to the image information and forms image light corresponding to the green light LG. The light modulation device 400B modulates the blue light LB according to the image information and forms image light corresponding to the blue light LB. For each of the light modulation devices 400R, 400G, and 400B, for example, a transmissive liquid crystal panel is used. In addition, polarizing plates (not shown) are arranged on each of the incident side and the emission side of each liquid crystal panel.

[0016] A field lens 300R is arranged on the incident side of the light modulation device 400R. The field lens 300R collimates the red light LR incident on the light modulation device 400R. A field lens 300G is arranged on the incident side of the light modulation device 400G. The field lens 300G collimates the green light LG incident on the light modulation device 400G. A field lens 300B is arranged on the incident side of the light modulation device 400B. The field lens 300B collimates the blue light LB incident on the light modulation device 400B. <{

[0017] The image light emitted from the light modulation devices 400R, 400G, and 400B is incident on the combining optical system 500. The combining optical system 500 combines the image light corresponding to each of the red light LR, green light LG, and blue light LB, and emits the combined image light toward the projection optical device 600. For example, a cross dichroic prism is used for the combining optical system 500.

[0018] The projection optical device 600 has a plurality of projection lenses. The projection optical device 600 enlarges and projects the image light combined by the combining optical system 500 toward the screen SCR. As a result, an enlarged video is displayed on the screen SCR.

[0019] Hereinafter, the configuration of the light source device 100 will be described using FIG. 2. FIG. 2 is a schematic configuration diagram showing the light source device 100 of the present embodiment. As shown in FIG. 2, the light source device 100 includes a light source unit 11, an afocal optical system 12, a homogenizer optical system 13, a condenser optical system 14, a wavelength conversion device 20, a pickup optical system 30, and a uniform illumination optical system 40.

[0020] The light source unit 11 is composed of a plurality of semiconductor lasers 11A and a plurality of collimator lenses 11B. Each of the plurality of semiconductor lasers 11A emits excitation light E in a blue wavelength band composed of laser light. The plurality of semiconductor lasers 11A are arranged in an array in a plane orthogonal to the illumination optical axis 100ax. The illumination optical axis 100ax is an optical axis parallel to the Y-axis and is defined as the central axis of a light beam including a plurality of excitation lights E emitted from the plurality of semiconductor lasers 11A. The excitation light E in the present embodiment corresponds to the first light in the claims.

[0021] The collimator lenses 11B are arranged in an array in a plane orthogonal to the illumination optical axis 100ax corresponding to each semiconductor laser 11A. The collimator lens 11B converts the excitation light E emitted from the semiconductor laser 11A corresponding to the collimator lens 11B at a predetermined divergence angle into parallel light. The number of the semiconductor lasers 11A and the collimator lenses 11B constituting the light source unit 11 is not particularly limited and may be one each.

[0022] The afocal optical system 12 includes a convex lens 12A and a concave lens 12B. The afocal optical system 12 reduces the beam diameter of the excitation light E composed of a parallel light beam emitted from the light source unit 11. As the afocal optical system 12, instead of the configuration composed of the above two lenses, for example, a light beam width reduction optical system combined with a polarization beam splitter mirror, a total reflection mirror, etc. may be used.

[0023] The homogenizer optical system 13 comprises a first multi-lens array 13A and a second multi-lens array 13B. The homogenizer optical system 13 converts the intensity distribution of the excitation light E into a uniform distribution, a so-called top-hat distribution, on the wavelength conversion layer 24 of the wavelength conversion device 20. The homogenizer optical system 13, together with the focusing optical system 14, superimposes multiple small beams of light emitted from multiple lenses of the first multi-lens array 13A and the second multi-lens array 13B onto the wavelength conversion layer 24 of the wavelength conversion device 20. This makes the intensity distribution of the excitation light E irradiated onto the wavelength conversion layer 24 uniform.

[0024] The focusing optical system 14 comprises a first lens 14A and a second lens 14B. The number of lenses constituting the focusing optical system 14 is not particularly limited. Each of the first lens 14A and the second lens 14B is made of a convex lens. The focusing optical system 14 is positioned in the optical path of the excitation light E between the homogenizer optical system 13 and the wavelength conversion device 20. The focusing optical system 14 focuses the excitation light E and directs it into the wavelength conversion layer 24 of the wavelength conversion device 20.

[0025] Next, the configuration of the wavelength conversion device 20 will be described. Figure 3 is a front view of the wavelength conversion device 20. As shown in Figure 3, the wavelength conversion device 20 of this embodiment comprises a wavelength conversion unit 21 and a rotation drive unit 22. The wavelength conversion unit 21 is a disc-shaped member that converts excitation light E emitted from the light source unit 11 into fluorescence Y. The rotation drive unit 22 consists of a motor that rotates the wavelength conversion unit 21 around a rotation axis O. In the following description, the direction perpendicular to the rotation axis O is referred to as the radial direction, the side of the radial direction that approaches the rotation axis O is referred to as the radially inward direction, and the side of the radial direction that moves away from the rotation axis O is referred to as the radially outward direction.

[0026] Figure 4 is a cross-sectional view of the wavelength conversion unit 21 along the IV-IV line in Figure 3. As shown in Figure 4, the wavelength conversion unit 21 is composed of a light-transmitting substrate 23, a wavelength conversion layer 24, a first support substrate 25, a second support substrate 26, a first reflective layer 27, a second reflective layer 28, and a dichroic layer 29.

[0027] The translucent substrate 23 is made of an annular plate material, for example, a transparent yttrium aluminum garnet (YAG) crystal. The translucent substrate 23 has a first surface 23a and a second surface 23b opposite to the first surface 23a. In this embodiment, of the two surfaces of the translucent substrate 23, the surface facing the pickup optical system 30 shown in Figure 2 is designated as the first surface 23a, and the surface facing the focusing optical system 14 is designated as the second surface 23b. The wavelength conversion layer 24 is provided on the first surface 23a. Furthermore, of the two sides of the translucent substrate 23 that intersect the first surface 23a and the second surface 23b, the side located radially inward is designated as the first side surface 23c, and the side located radially outward is designated as the second side surface 23d.

[0028] The material of the translucent substrate 23 is not limited to transparent YAG, as long as it is a translucent material, for example, silicon carbide, sapphire, alumina, glass, etc. may be used. It is desirable that the material of the translucent substrate 23 be a material with high thermal conductivity. When transparent YAG is used as the material of the translucent substrate 23, the thermal conductivity of the translucent substrate 23 is higher than that of, for example, glass material, so that the heat from the wavelength conversion layer 24 is easily transferred to the translucent substrate 23, and the heat dissipation of the wavelength conversion layer 24 can be improved. Transparent YAG is a material obtained by removing the cerium activator from YAG (YAG:Ce) that constitutes the wavelength conversion layer 24.

[0029] The wavelength conversion layer 24 converts the excitation light E that passes through the translucent substrate 23 into fluorescence Y in the yellow wavelength band, which is different from the blue wavelength band. In this embodiment, the wavelength conversion layer 24 is formed in an annular shape on the first surface 23a of the annular translucent substrate 23. That is, as shown in Figure 3, the wavelength conversion layer 24 is provided in an annular shape around the rotation axis O. Of the two surfaces of the wavelength conversion layer 24, the surface facing the pickup optical system 30 shown in Figure 2 is designated as the first surface 24a, and the surface facing the translucent substrate 23 is designated as the second surface 24b. The fluorescence Y in this embodiment corresponds to the second light in the claims.

[0030] The wavelength conversion layer 24 generates heat in conjunction with the emission of fluorescence Y. If the temperature of the wavelength conversion layer 24 exceeds a predetermined temperature, the wavelength conversion efficiency may decrease significantly, potentially reducing the amount of fluorescence Y emitted. In the wavelength conversion device 20 of this embodiment, the wavelength conversion layer 24 rotates together with the translucent substrate 23, so the incident position of the excitation light E on the wavelength conversion layer 24 moves over time. This makes it easier to cool the wavelength conversion layer 24, and suppresses the decrease in wavelength conversion efficiency due to the temperature rise of the wavelength conversion layer 24.

[0031] The wavelength conversion layer 24 receives excitation light E from its second surface 24b, which faces the translucent substrate 23, and emits fluorescence Y from its first surface 24a. Therefore, the wavelength conversion device 20 of this embodiment is a transmissive type wavelength conversion device that emits illumination light LW containing fluorescence Y from the first surface 24a, which is opposite to the second surface 24b of the wavelength conversion layer 24 into which the excitation light E is incident.

[0032] The wavelength conversion layer 24 is composed of a wavelength conversion material containing a ceramic phosphor made of a polycrystalline phosphor. The wavelength band of fluorescence Y is, for example, the yellow wavelength band of 490 to 750 nm. That is, fluorescence Y is yellow fluorescence containing red and green light components. The wavelength conversion layer 24 may contain a single-crystal phosphor instead of a polycrystalline phosphor. Alternatively, the wavelength conversion layer 24 may be composed of a material in which a large number of phosphor particles are dispersed in a binder made of glass or resin.

[0033] Specifically, the material of the wavelength conversion layer 24 in this embodiment includes, for example, a yttrium aluminum garnet (YAG) phosphor. Taking YAG:Ce containing cerium (Ce) as an activator as an example, the material used for the wavelength conversion layer 24 may be a material obtained by mixing raw material powders containing constituent elements such as Y2O3, Al2O3, and CeO3 and performing a solid-phase reaction; Y-Al-O amorphous particles obtained by wet methods such as the coprecipitation method and the sol-gel method; or YAG particles obtained by gas-phase methods such as the spray drying method, flame decomposition method, and thermal plasma method.

[0034] The first support substrate 25 is made of a disc-shaped plate material, for example, made of transparent YAG crystal. The outer diameter of the first support substrate 25 is smaller than the inner diameter of the translucent substrate 23. Therefore, the first support substrate 25 is positioned radially inward of the translucent substrate 23 and is bonded to the first side surface 23c of the translucent substrate 23 with an adhesive or the like. The material of the first support substrate 25 is not particularly limited to transparent YAG, and for example, silicon carbide, sapphire, alumina, glass, etc. may be used. It is desirable that the material of the first support substrate 25 be a material with high thermal conductivity.

[0035] The second support substrate 26 is made of an annular plate material, for example, made of transparent YAG crystal. The inner diameter of the second support substrate 26 is larger than the outer diameter of the translucent substrate 23. Therefore, the second support substrate 26 is positioned radially outside the translucent substrate 23 and is bonded to the second side surface 23d of the translucent substrate 23 by an adhesive or the like. The material of the second support substrate 26 is not particularly limited to transparent YAG, and for example, silicon carbide, sapphire, alumina, glass, etc. may be used. It is desirable that the material of the second support substrate 26 be made of a material with high thermal conductivity.

[0036] In this embodiment, the radial width W1 of the translucent substrate 23 is smaller than the radial width W2 of the wavelength conversion layer 24. That is, the radial ends of the wavelength conversion layer 24 protrude outside the translucent substrate 23. Therefore, of the second surface 24b of the wavelength conversion layer 24, the central part is in contact with the translucent substrate 23 via the dichroic layer 9, the radially inner end is in contact with the first support substrate 25 via the dichroic layer 9, and the radially outer end is in contact with the second support substrate 26 via the dichroic layer 9. In this configuration, the translucent substrate 23, the first support substrate 25, and the second support substrate 26 are all made of YAG-based material, so their thermal conductivity is higher than that of general glass materials. As a result, heat from the wavelength conversion layer 24 is easily transferred not only to the translucent substrate 23 but also to the first support substrate 25 and the second support substrate 26, further improving the heat dissipation of the wavelength conversion layer 24.

[0037] The first reflective layer 27 is provided between the first side surface 23c of the translucent substrate 23 and the side surface 25c of the first support substrate 25. The first reflective layer 27 is composed of, for example, a dielectric multilayer film, a highly reflective metal film such as silver or aluminum, or a highly reflective adhesive. This allows for the formation of a first reflective layer 27 with excellent reflectivity. When forming the first reflective layer 27, the dielectric multilayer film, metal film, adhesive, etc., can be formed on either the first side surface 23c of the translucent substrate 23 or the side surface 25c of the first support substrate 25 before joining the translucent substrate 23 and the first support substrate 25. The surface of the first reflective layer 27 facing the first side surface 23c of the translucent substrate 23 is the first reflective surface 27a that reflects fluorescence Y. The first reflective surface 27a is perpendicular to the first surface 23a and the second surface 23b of the translucent substrate 23.

[0038] The second reflective layer 28 is provided between the second side surface 23d of the translucent substrate 23 and the side surface 26d of the second support substrate 26. Similar to the first reflective layer 27, the second reflective layer 28 is composed of, for example, a dielectric multilayer film, a highly reflective metal film such as silver or aluminum, or a highly reflective adhesive. This allows for the formation of a second reflective layer 28 with excellent reflectivity. When forming the second reflective layer 28, the dielectric multilayer film, metal film, adhesive, etc., can be formed on either the second side surface 23d of the translucent substrate 23 or the side surface 26d of the second support substrate 26 before joining the translucent substrate 23 and the second support substrate 26. The surface of the second reflective layer 28 facing the second side surface 23d of the translucent substrate 23 is the second reflective surface 28a that reflects fluorescence. The second reflective surface 28a is perpendicular to the first surface 23a and the second surface 23b of the translucent substrate 23.

[0039] The dichroic layer 29 is provided between the first surface 23a of the translucent substrate 23 and the second surface 24b of the wavelength conversion layer 24. In this embodiment, the dichroic layer 29 is provided not only between the first surface 23a of the translucent substrate 23 and the second surface 24b of the wavelength conversion layer 24, but also across the first surface 25a of the first support substrate 25 and the first surface 26a of the second support substrate 26, however, it is sufficient that it is provided at least between the first surface 23a of the translucent substrate 23 and the second surface 24b of the wavelength conversion layer 24. The dichroic layer 29 transmits excitation light E and reflects fluorescence Y. The dichroic layer 29 is composed of, for example, a dielectric multilayer film.

[0040] The excitation light E emitted from the light source unit 11 enters the translucent substrate 23 from its second surface 23b, passes through the translucent substrate 23, and enters the wavelength conversion layer 24 from its second surface 24b. Therefore, the second surface 23b of the translucent substrate 23 may be provided with an anti-reflective coating to suppress the reflection of the excitation light E. The anti-reflective coating is, for example, made of an AR coating. This can increase the utilization efficiency of the excitation light E. Since the excitation light E is focused by the focusing optical system 14, the width W3 of the irradiation area of ​​the excitation light E on the wavelength conversion layer 24 is smaller than the width W2 of the wavelength conversion layer 24.

[0041] The thickness of the wavelength conversion layer 24 is set such that not all of the excitation light E is wavelength-converted as it travels through the inside of the wavelength conversion layer 24. Therefore, the wavelength conversion layer 24 emits not only the yellow fluorescence Y generated by wavelength conversion, but also the unconverted blue excitation light E1 from its first surface 24a. As a result, the wavelength conversion device 20 emits white illumination light LW containing the excitation light E1 and fluorescence Y from the first surface 24a of the wavelength conversion layer 24 towards the focusing optical system 14.

[0042] A portion of the fluorescence Y generated in the wavelength conversion layer 24 travels toward the second surface 24b, i.e., toward the translucent substrate 23, and is incident on the dichroic layer 29 provided on the first surface 23a of the translucent substrate 23. Most of the fluorescence Y incident on the dichroic layer 29 is reflected toward the opposite side of the translucent substrate 23 and emitted from the first surface 24a of the wavelength conversion layer 24. On the other hand, because fluorescence Y is unpolarized light, a portion of the fluorescence Y incident on the dichroic layer 29 passes through the dichroic layer 29 due to the optical properties of the dichroic layer and is incident on the translucent substrate 23.

[0043] Figure 5 shows the problems with conventional light source devices. As shown in Figure 5, in a conventional light source device, fluorescence Y incident on the translucent substrate 123 from the wavelength conversion layer 24 via the dichroic layer 29 propagates through the interior of the translucent substrate 123 while undergoing total internal reflection. At this time, some of the fluorescence Yp Yp1 propagating through the interior of the translucent substrate 123 may be incident on the first surface 123a or the second surface 123b of the translucent substrate 123 at an incident angle less than the critical angle, and may leak to the outside. Such fluorescence is difficult to use as illumination light, and there is a risk that the utilization efficiency of fluorescence will decrease.

[0044] In contrast, in the light source device 100 of this embodiment, as shown in Figure 4, a first reflective surface 27a and a second reflective surface 28a are provided that are orthogonal to the first surface 23a and the second surface 23b of the translucent substrate 23. Therefore, the fluorescent Y incident on the translucent substrate 23 from the wavelength conversion layer 24 via the dichroic layer 29 is trapped inside the translucent substrate 23 while repeatedly being reflected by the first reflective surface 27a and the second reflective surface 28a, and propagation to the first support substrate 25 or the second support substrate 26 is suppressed. The fluorescent Y trapped inside the translucent substrate 23 is then incident on the wavelength conversion layer 24 again via the dichroic layer 29 while repeatedly being reflected, and is then emitted from the first surface 24a of the wavelength conversion layer 24, as shown by the fluorescent Yp2. In this way, with the light source device 100 of this embodiment, leakage of fluorescent Y from the translucent substrate 23 is suppressed, and the utilization efficiency of fluorescent Y can be increased compared to conventional methods.

[0045] According to the inventor's simulations, it was confirmed that when reflective surfaces are formed on two sides of a translucent substrate, the amount of fluorescence emitted from the first surface of the wavelength conversion layer increases by more than 10% under specific simulation conditions compared to when no reflective surfaces are formed.

[0046] In this embodiment, since the radial width W1 of the translucent substrate 23 is smaller than the radial width W2 of the wavelength conversion layer 24, the first reflective layer 27 and the second reflective layer 28 are located inside the two sides 24c and 24d of the wavelength conversion layer 24. In other words, when viewed from a direction perpendicular to the first surface 23a of the translucent substrate 23, the first reflective layer 27 and the second reflective layer 28 are provided in a position that overlaps with the wavelength conversion layer 24. Alternatively, the first reflective layer 27 and the second reflective layer 28 may be located outside the two sides 24c and 24d of the wavelength conversion layer 24. That is, when viewed from a direction perpendicular to the first surface 23a of the translucent substrate 23, the first reflective layer 27 and the second reflective layer 28 may be provided in a position that does not overlap with the wavelength conversion layer 24. However, according to the configuration of this embodiment, the fluorescent Yp trapped in the translucent substrate 23 is more easily re-incidentated into the wavelength conversion layer 24, and the leakage of fluorescent Yp can be further reduced.

[0047] As shown in Figure 2, the illumination light LW emitted from the wavelength converter 20 is incident on the pickup optical system 30. The pickup optical system 30 comprises a first collimating lens 31 and a second collimating lens 32. The number of lenses constituting the pickup optical system 30 is not particularly limited. The pickup optical system 30 substantially parallelizes the illumination light LW emitted from the wavelength converter 20. The first collimating lens 31 and the second collimating lens 32 are each made of a convex lens. The illumination light LW parallelized by the pickup optical system 30 is incident on the uniform illumination optical system 40.

[0048] The uniform illumination optical system 40 includes a first lens array 41, a second lens array 42, a polarization conversion element 43, and a superimposed lens 44.

[0049] The first lens array 41 has a plurality of first lenses 41a for dividing the illumination light LW from the light source device 100 into a plurality of partial luminous beams. The plurality of first lenses 41a are arranged in a matrix in a plane perpendicular to the illumination optical axis 100ax.

[0050] The second lens array 42 has a plurality of second lenses 42a corresponding to a plurality of first lenses 41a of the first lens array 41. The plurality of second lenses 42a are arranged in a matrix in a plane perpendicular to the illumination optical axis 100ax. Together with the superimposed lens 44, the second lens array 42 images the images of each first lens 41a of the first lens array 41 near the image forming areas of the optical modulator 400R, optical modulator 400G, and optical modulator 400B, respectively.

[0051] The polarization conversion element 43 converts the illumination light LW emitted from the second lens array 42 into linearly polarized light having a predetermined polarization direction. The polarization conversion element 43 includes a polarization separation film and a phase difference plate (not shown).

[0052] The superimposing lens 44 focuses each partial light beam emitted from the polarization conversion element 43 and superimposes it near the image forming areas of the optical modulator 400R, optical modulator 400G, and optical modulator 400B, respectively.

[0053] [Effects of the First Embodiment] The light source device 100 of this embodiment includes a light source unit 11 that emits excitation light E, a wavelength conversion layer 24 that converts the excitation light E into fluorescence Y, and a translucent substrate 23 having a first surface 23a and a second surface 23b, with the wavelength conversion layer 24 provided on the first surface 23a. The excitation light E emitted from the light source unit 11 enters the translucent substrate 23 from the second surface 23b, passes through the translucent substrate 23, and enters the wavelength conversion layer 24 from the first surface 23a. A portion of the fluorescence Y Yp converted in the wavelength conversion layer 24 enters the translucent substrate 23 from the first surface 23a. The light source device 100 has a first reflective surface 27a and a second reflective surface 28a that intersect the first surface 23a and the second surface 23b of the translucent substrate 23 and reflect fluorescence Y.

[0054] As described above, according to the light source device 100 of this embodiment, some of the fluorescent Y incident on the translucent substrate 23 is trapped inside the translucent substrate 23 by the first reflective surface 27a and the second reflective surface 28a, then incident on the wavelength conversion layer 24 again, and emitted to the outside from the first surface 24a of the wavelength conversion layer 24. In this way, leakage of fluorescent Y from the translucent substrate 23 is suppressed, and the utilization efficiency of fluorescent Y can be increased compared to conventional methods. As a result, the light source device 100 of this embodiment can increase the amount of fluorescent Y that can be used as illumination light LW, and can generate bright illumination light LW.

[0055] The projector 10 of this embodiment includes a light source device 100, optical modulators 400R, 400G, and 400B that modulate illumination light LW incident from the light source device 100, and a projection optical device 600 that projects the light modulated by the optical modulators 400R, 400G, and 400B.

[0056] According to the projector 10 of this embodiment, a bright image can be projected by modulating the bright illumination light LW incident from the light source device 100.

[0057] [Second Embodiment] A second embodiment of the present invention will be described below with reference to Figure 6. The basic configuration of the projector and light source device in the second embodiment is the same as in the first embodiment, but the configuration of the wavelength conversion device differs from that of the first embodiment. Therefore, a description of the basic configuration of the projector and light source device will be omitted.

[0058] Figure 6 is a cross-sectional view of the wavelength conversion unit 51 in the light source device of the second embodiment. In Figure 6, components common to both Figure 4 and the first embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0059] As shown in Figure 6, the wavelength conversion unit 51 of this embodiment is composed of a light-transmitting substrate 23, a wavelength conversion layer 24, a first support substrate 55, a second support substrate 56, a first reflective layer 27, a second reflective layer 28, and a dichroic layer 29.

[0060] In the wavelength conversion unit 21 of the first embodiment, the first support substrate 25 and the second support substrate 26 were each made of a light-transmitting material such as transparent YAG. In contrast, in the wavelength conversion unit 51 of this embodiment, the first support substrate 55 and the second support substrate 56 are each made of a metal material with high thermal conductivity such as aluminum or copper. The dichroic layer 29 is provided between the first surface 23a of the light-transmitting substrate 23 and the second surface 24b of the wavelength conversion layer 24, and across the first surface 55a of the first support substrate 55 and the first surface 56a of the second support substrate 56.

[0061] The first reflective layer 27 and the second reflective layer 28 each have the same configuration as in the first embodiment. That is, the first reflective layer 27 is provided between the first side surface 23c of the translucent substrate 23 and the side surface 55c of the first support substrate 55. The second reflective layer 28 is provided between the second side surface 23d of the translucent substrate 23 and the side surface 56d of the second support substrate 56. The first reflective layer 27 and the second reflective layer 28 are composed of, for example, a dielectric multilayer film, a highly reflective metal film such as silver or aluminum, or a highly reflective adhesive. The other components of the light source device are the same as those of the light source device in the first embodiment.

[0062] Furthermore, if the first support substrate 55 is made of a highly reflective metal material such as aluminum, the first reflective layer 27 does not necessarily have to be provided. In that case, it is desirable that the side surface 55c of the first support substrate 55 be mirror-finished. As a result, the side surface 55c of the first support substrate 55 functions as a first reflective surface. Similarly, if the second support substrate 56 is made of a highly reflective metal material, the second reflective layer 28 does not necessarily have to be provided. In that case, it is desirable that the side surface 56d of the second support substrate 56 be mirror-finished. As a result, the side surface 56d of the second support substrate 56 functions as a second reflective surface.

[0063] [Effects of the second embodiment] In this embodiment as well, the same effects as in the first embodiment can be obtained, such as the ability to increase the utilization efficiency of fluorescent Y, because the leakage of fluorescent Y from the translucent substrate 23 is suppressed by the action of the first reflective surface 27a and the second reflective surface 28a.

[0064] In this embodiment, since the first support substrate 55 and the second support substrate 56 are each made of a metal with high thermal conductivity, heat from the wavelength conversion layer 24 is easily transferred to the first support substrate 55 and the second support substrate 56, thereby improving the heat dissipation of the wavelength conversion layer 24. This makes it possible to suppress the decrease in wavelength conversion efficiency that occurs with a rise in the temperature of the wavelength conversion layer 24.

[0065] [Third Embodiment] A third embodiment of the present invention will be described below with reference to Figure 7. The basic configuration of the projector and light source device in the third embodiment is the same as in the first embodiment, but the configuration of the wavelength converter differs from that of the first embodiment. Therefore, a description of the basic configuration of the projector and light source device will be omitted.

[0066] Figure 7 is a cross-sectional view of the wavelength conversion unit 61 in the light source device of the third embodiment. In Figure 7, components common to both Figure 6 and the second embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0067] As shown in Figure 7, the wavelength conversion unit 61 of this embodiment is composed of a translucent substrate 23, a wavelength conversion layer 24, a first support substrate 55, a first reflective layer 27, a second reflective layer 28, and a dichroic layer 29. The wavelength conversion unit 61 of this embodiment has a configuration that omits the second support substrate 56 from the wavelength conversion unit 51 of the second embodiment. The first support substrate 55 is made of a metal material with high thermal conductivity, such as aluminum or copper, similar to the second embodiment. The first reflective layer 27 is provided between the first side surface 23c of the translucent substrate 23 and the side surface 55c of the first support substrate 55. The second reflective layer 28 is provided on the second side surface 23d of the translucent substrate 23. The other components of the light source device are the same as those of the light source device in the first embodiment.

[0068] [Effects of the third embodiment] In this embodiment as well, the same effects as in the first embodiment can be obtained, such as the ability to increase the utilization efficiency of fluorescent Y, because the leakage of fluorescent Y from the translucent substrate 23 is suppressed by the action of the first reflective surface 27a and the second reflective surface 28a.

[0069] In this embodiment, the second support substrate 56 of the second embodiment is unnecessary, thus reducing the number of components in the light source device.

[0070] It should be noted that the technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. Furthermore, one aspect of the present invention can be a configuration that appropriately combines the characteristic features of each of the embodiments described above.

[0071] The light source device in the above embodiment has both a first reflective surface and a second reflective surface, but it may also have only one of the first or second reflective surface. In that case, it is desirable that the light source device has only the first reflective surface. This is because having the first reflective surface suppresses the propagation of fluorescence to the first support substrate, which has a larger area than the second support substrate, and reduces fluorescence leakage compared to the case where only the second reflective surface is present.

[0072] In the above embodiment, the first and second reflective surfaces were provided perpendicular to the first and second surfaces of the translucent substrate, but they may be inclined with respect to the first and second surfaces of the translucent substrate. That is, the first and second sides of the translucent substrate may be tapered surfaces. However, if the first and second reflective surfaces are perpendicular to the first and second surfaces of the translucent substrate, the angle of the fluorescence propagation direction will not change even if the fluorescence is reflected multiple times by each reflective surface. Therefore, the fluorescence is easily trapped inside the translucent substrate, and fluorescence leakage can be effectively suppressed.

[0073] The light source device of this embodiment has a rotation drive unit for rotating the wavelength conversion unit, but it does not necessarily have to have a rotation drive unit. That is, the wavelength conversion unit, which includes the wavelength conversion layer and the translucent substrate, does not necessarily have to be rotatable and may be fixed. Also, in the above embodiment, the wavelength conversion layer had an annular shape, but it does not necessarily have to be a continuous annular shape, and may be, for example, interrupted in the middle. In that case, yellow light and blue light will be emitted alternately, and it is possible to generate pseudo-white illumination light.

[0074] Furthermore, the specific details regarding the shape, number, arrangement, materials, and other characteristics of each component of the light source device and projector are not limited to the embodiments described above and can be modified as appropriate. Also, while the above embodiments show an example where the light source device according to the present invention is mounted on a projector using a liquid crystal panel, the invention is not limited to this. The light source device of the present invention may also be applied to a projector using a digital micromirror device as an optical modulator. Moreover, the projector does not necessarily have multiple optical modulators; it may be a single-chip projector having only one optical modulator.

[0075] The above embodiment shows an example of applying the light source device of the present invention to a projector, but it 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.

[0076] [Summary of this disclosure] A summary of this disclosure is provided below.

[0077] (Note 1) A light source unit that emits first light in the first wavelength band, A wavelength conversion layer that converts the first light into a second light in a second wavelength band different from the first wavelength band, A translucent substrate having a first surface and a second surface opposite to the first surface, wherein the wavelength conversion layer is provided on the first surface, Equipped with, The first light emitted from the light source unit enters the translucent substrate from the second surface, passes through the translucent substrate, and enters the wavelength conversion layer from the first surface. A portion of the second light converted in the wavelength conversion layer is incident on the translucent substrate from the first surface. A light source device having a first reflective surface that intersects the first and second surfaces of the light-transmitting substrate and reflects the second light.

[0078] According to the configuration described in Appendix 1, when a portion of the second light converted in the wavelength conversion layer is incident on the translucent substrate, the second light is reflected by the first reflective surface, which suppresses its propagation over long distances within the translucent substrate. This suppresses leakage of the second light from the translucent substrate and improves the utilization efficiency of the second light.

[0079] (Note 2) The light source device according to Appendix 1, wherein the first reflective surface is perpendicular to the first surface and the second surface.

[0080] According to the configuration described in Appendix 2, the angle of the direction of propagation of the second light does not change when the second light is reflected by the first reflective surface, thus effectively suppressing leakage of the second light.

[0081] (Note 3) The light source device according to Appendix 1 or Appendix 2, wherein, when viewed from a direction perpendicular to the first surface, the first reflective surface is provided in a position that overlaps with the wavelength conversion layer.

[0082] According to the configuration described in Appendix 3, the second light propagating through the translucent substrate is easily re-incident to the wavelength conversion layer, and the second light can be efficiently emitted from the wavelength conversion layer.

[0083] (Note 4) The system further comprises a first support substrate that supports the light-transmitting substrate, The first support substrate is rotatable about a rotation axis extending in the direction normal to the first surface. The light source device according to any one of the appendices 1 to 3, wherein the first reflective surface is provided at the interface between the translucent substrate and the first support substrate.

[0084] According to the configuration described in Appendix 4, the incident position of the first light in the wavelength conversion layer can be moved over time by rotating the first support substrate. This makes it possible to suppress the decrease in wavelength conversion efficiency that occurs with the temperature rise of the wavelength conversion layer.

[0085] (Note 5) The first support substrate is made of a metal material, as described in Appendix 4, for the light source device.

[0086] According to the configuration described in Appendix 5, the temperature rise of the wavelength conversion layer can be efficiently suppressed by using a metal material with high thermal conductivity. Furthermore, the reflective layer can be eliminated by using a metal material with high reflectivity.

[0087] (Note 6) The light source device as described in Appendix 4, wherein the first support substrate is made of the same material as the light-transmitting substrate.

[0088] According to the configuration described in Appendix 6, heat generated in the wavelength conversion layer can be easily transferred from the translucent substrate to the first support substrate, thereby suppressing a decrease in wavelength conversion efficiency.

[0089] (Note 7) A light source device according to any one of appendices 4 to 6, further comprising a second reflective surface provided on the surface of the translucent substrate opposite to the interface, which reflects the second light.

[0090] According to the configuration described in Appendix 7, the second light incident on the translucent substrate can be confined to the region between the first and second reflective surfaces, thereby more effectively suppressing leakage of the second light.

[0091] (Note 8) The light source device according to Appendix 7, wherein the second reflective surface is perpendicular to the first and second surfaces.

[0092] According to the configuration described in Appendix 8, the angle of the direction of propagation of the second light does not change when the second light is reflected by the second reflective surface, thus effectively suppressing leakage of the second light.

[0093] (Note 9) The light source device according to Appendix 7 or Appendix 8, wherein, when viewed from a direction perpendicular to the first surface, the second reflective surface is provided in a position that overlaps with the wavelength conversion layer.

[0094] According to the configuration described in Appendix 9, the second light propagating through the translucent substrate is easily re-incident to the wavelength conversion layer, and the second light can be efficiently emitted from the wavelength conversion layer.

[0095] (Note 10) The light-transmitting substrate is further provided on the side opposite to the first support substrate, and includes a second support substrate that supports the light-transmitting substrate. The light source device according to Appendix 9, wherein the second reflective surface is provided at the interface between the translucent substrate and the second support substrate.

[0096] According to the configuration described in Appendix 10, a second reflective surface can be reliably formed between the translucent substrate and the second support substrate.

[0097] (Note 11) The light source device according to any one of the appendices 7 to 10, wherein each of the first reflective surface and the second reflective surface is composed of a reflective layer made of a dielectric multilayer film, a metal film, or an adhesive layer containing metal.

[0098] According to the configuration described in Appendix 11, a reflective surface with excellent reflectivity can be formed.

[0099] (Note 12) The light source device according to any one of the appendices 1 to 11, further comprising a dichroic layer provided between the first surface of the light-transmitting substrate and the wavelength conversion layer, which transmits the first light and reflects the second light.

[0100] According to the configuration described in Appendix 12, the first light emitted from the light source is incident on the wavelength conversion layer, while the incidence of the second light generated in the wavelength conversion layer onto the translucent substrate is minimized, thereby ensuring sufficient light intensity of the second light emitted from the wavelength conversion layer.

[0101] (Note 13) A light source device described in any one of the appendices 1 through 12, A light modulator that modulates the light emitted from the light source device according to image information, A projection optical device that projects light modulated by the aforementioned optical modulation device, A projector equipped with [a specific feature].

[0102] According to the configuration described in Appendix 13, a projector capable of projecting bright images can be realized. [Explanation of Symbols]

[0103] 10...Projector, 11...Light source, 23...Translucent substrate, 23a...First surface, 23b...Second surface, 24...Wavelength conversion layer, 25, 55...First support substrate, 26, 56...Second support substrate, 27...First reflective layer, 27a...First reflective surface, 28...Second reflective layer, 28a...Second reflective surface, 29...Dichroic layer, 100...Light source device, 400R, 400G, 400B...Optical modulation device, 600...Projection optics device, E...Excitation light (first light), Y...Fluorescence (second light).

Claims

1. A light source unit that emits first light in the first wavelength band, A wavelength conversion layer that converts the first light into a second light in a second wavelength band different from the first wavelength band, A translucent substrate having a first surface and a second surface opposite to the first surface, wherein the wavelength conversion layer is provided on the first surface, Equipped with, The first light emitted from the light source unit enters the translucent substrate from the second surface, passes through the translucent substrate, and enters the wavelength conversion layer from the first surface. A portion of the second light converted in the wavelength conversion layer is incident on the translucent substrate from the first surface. A light source device having a first reflective surface that intersects the first and second surfaces of the light-transmitting substrate and reflects the second light.

2. The light source device according to claim 1, wherein the first reflective surface is perpendicular to the first surface and the second surface.

3. The light source device according to claim 1 or claim 2, wherein, when viewed from a direction perpendicular to the first surface, the first reflective surface is provided in a position that overlaps with the wavelength conversion layer.

4. The system further comprises a first support substrate that supports the light-transmitting substrate, The first support substrate is rotatable about a rotation axis extending in the direction normal to the first surface. The light source device according to claim 1 or claim 2, wherein the first reflective surface is provided at the interface between the light-transmitting substrate and the first support substrate.

5. The light source device according to claim 4, wherein the first support substrate is made of a metal material.

6. The light source device according to claim 4, wherein the first support substrate is made of the same material as the light-transmitting substrate.

7. The light source device according to claim 4, further comprising a second reflective surface provided on the surface of the translucent substrate opposite to the interface, which reflects the second light.

8. The light source device according to claim 7, wherein the second reflective surface is perpendicular to the first surface and the second surface.

9. The light source device according to claim 7, wherein, when viewed from a direction perpendicular to the first surface, the second reflective surface is provided in a position that overlaps with the wavelength conversion layer.

10. The light-transmitting substrate is further provided on the side opposite to the first support substrate, and includes a second support substrate that supports the light-transmitting substrate. The light source device according to claim 9, wherein the second reflective surface is provided at the interface between the light-transmitting substrate and the second support substrate.

11. The light source device according to claim 7, wherein each of the first reflective surface and the second reflective surface is composed of a reflective layer made of a dielectric multilayer film, a metal film, and an adhesive layer containing metal.

12. The light source device according to claim 1 or claim 2, further comprising a dichroic layer provided between the first surface of the light-transmitting substrate and the wavelength conversion layer, which transmits the first light and reflects the second light.

13. A light source device according to claim 1 or claim 2, A light modulator that modulates the light emitted from the light source device according to image information, A projection optical device that projects light modulated by the aforementioned optical modulation device, A projector equipped with [a specific feature].

Images