Light source device and projector

Abstract

To provide a light source device and a projector capable of improving light use efficiency of fluorescence.SOLUTION: A light source device according to an aspect of the present disclosure includes a light source configured to emit first light, a wavelength conversion layer configured to convert first light incident from the light source into second light having a wavelength band different from that of the first light, a light-transmissive substrate having a first surface and a second surface opposite to the first surface, the wavelength conversion layer being provided on the first surface side, a dichroic film provided between the first surface of the light-transmissive substrate and the wavelength conversion layer and configured to transmit the first light and reflect the second light, and a concave-convex structure provided on the first surface side of the light-transmissive substrate.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Patent Document 1 below discloses a light source device that generates illumination light containing fluorescence and a portion of the excitation light by irradiating excitation light onto a phosphor layer formed on a transparent substrate. The excitation light emitted from the excitation light source sequentially passes through the substrate and a dichroic layer before entering the phosphor layer. Of the fluorescence emitted from the phosphor layer in all directions, the fluorescence that travels toward the substrate is reflected by the dichroic layer and extracted on the side opposite the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-3923 Summary of the Invention [Problem to be solved by the invention]

[0004] In the light source device of Patent Document 1, a dichroic layer that transmits excitation light and reflects fluorescent light is provided between the substrate and the phosphor layer in order to extract the fluorescent light in the desired direction, i.e., the side opposite the substrate. However, of the fluorescent light that enters the dichroic layer, the P-polarized component that is incident at the Brewster angle passes through the dichroic layer and leaks into the substrate. The fluorescent light that leaks into the substrate propagates through the substrate due to total internal reflection and is emitted to the outside from the side of the substrate, making it impossible to use as illumination light, resulting in a problem of reduced light utilization efficiency of the fluorescent light. [Means for solving the problem]

[0005] In order to solve the above problems, according to a first aspect of the present invention, there is provided a light source device comprising: a light source that emits first light; a wavelength conversion layer that converts the first light incident from the light source into second light of a wavelength band different from the first light; a light-transmitting substrate having a first surface and a second surface opposite to the first surface, with the wavelength conversion layer provided on the first surface side; a dichroic film 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; and a concavo-convex structure provided on the first surface side of the light-transmitting substrate.

[0006] According to a second aspect of the present invention, there is provided a projector comprising the light source device of the second aspect, a light modulation device that modulates light incident from the light source device, and a projection optical device that projects the light modulated by the light modulation device. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic configuration diagram illustrating a projector. [Figure 2] FIG. 2 is a schematic diagram illustrating the configuration of a light source device. [Figure 3] FIG. 1 is a cross-sectional view showing a configuration of a wavelength conversion device. [Figure 4] FIG. 1 is a plan view showing a configuration of a wavelength conversion device. [Figure 5] FIG. 10 is a cross-sectional view showing the configuration of a wavelength converter according to a first modified example. [Figure 6] FIG. 10 is a cross-sectional view showing the configuration of a wavelength converter according to a second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the drawings used in the following description may show characteristic portions enlarged for convenience in order to make the characteristics easier to understand, and the dimensional proportions of each component may not necessarily be the same as those in reality.

[0009] FIG. 1 is a schematic configuration diagram showing a projector according to the present embodiment. 1, the projector 1 of this embodiment is a projection-type image display device that displays an image on a screen SCR. The projector 1 includes a light source device 2, a color separation optical system 3, a light modulation device 4R, a light modulation device 4G, a light modulation device 4B, a combining optical system 5, and a projection optical device 6.

[0010] The light source device 2 emits white illumination light WL toward the color separation optical system 3. The configuration of the light source device 2 will be described in detail later.

[0011] The color separation optical system 3 separates the illumination light WL emitted from the light source device 2 into red light LR, green light LG, and blue light LB. The color separation optical system 3 includes a first dichroic mirror 7a, a second dichroic mirror 7b, a first total reflection mirror 8a, a second total reflection mirror 8b, a third total reflection mirror 8c, a first relay lens 9a, and a second relay lens 9b.

[0012] The first dichroic mirror 7a separates the illumination light WL from the light source device 2 into red light LR and light containing green light LG and blue light LB. The first dichroic mirror 7a transmits the red light LR and reflects the light containing green light LG and blue light LB. On the other hand, the second dichroic mirror 7b reflects the green light LG and transmits the blue light LB. In this way, the second dichroic mirror 7b separates the light containing green light LG and blue light LB into green light LG and blue light LB.

[0013] The first total reflection mirror 8a is disposed in the optical path of the red light LR and reflects the red light LR that has passed through the first dichroic mirror 7a toward the optical modulation device 4R. On the other hand, the second total reflection mirror 8b and the third total reflection mirror 8c are disposed in the optical path of the blue light LB and guide the blue light LB that has passed through the second dichroic mirror 7b toward the optical modulation device 4B. The green light LG is reflected from the second dichroic mirror 7b toward the optical modulation device 4G.

[0014] The first relay lens 9a is disposed between the second dichroic mirror 7b and the second total reflection mirror 8b in the optical path of the blue light LB. The second relay lens 9b is disposed between the second total reflection mirror 8b and the third total reflection mirror 8c in the optical path of the blue light LB. The first relay lens 9a and the second relay lens 9b compensate for optical loss of the blue light LB caused by the optical path length of the blue light LB being longer than the optical path lengths of the red light LR and the green light LG.

[0015] The light modulation device 4R modulates the red light LR according to image information to form image light corresponding to the red light LR. The light modulation device 4G modulates the green light LG according to image information to form image light corresponding to the green light LG. The light modulation device 4B modulates the blue light LB according to image information to form image light corresponding to the blue light LB.

[0016] Each of the light modulation devices 4R, 4G, and 4B uses, for example, a transmissive liquid crystal panel. Polarizing plates (not shown) are arranged on the incident side and the exit side of the liquid crystal panel.

[0017] A field lens 10R is disposed on the incident side of the optical modulation device 4R. The field lens 10R collimates the red light LR incident on the optical modulation device 4R. A field lens 10G is disposed on the incident side of the optical modulation device 4G. The field lens 10G collimates the green light LG incident on the optical modulation device 4G. A field lens 10B is disposed on the incident side of the optical modulation device 4B. The field lens 10B collimates the blue light LB incident on the optical modulation device 4B.

[0018] The image light emitted from the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B is incident on the combining optical system 5. The combining optical system 5 combines the image light corresponding to the red light LR, the green light LG, and the blue light LB, respectively, and emits the combined image light toward the projection optical device 6. The combining optical system 5 uses, for example, a cross dichroic prism.

[0019] The projection optical device 6 has a plurality of projection lenses. The projection optical device 6 enlarges and projects the image light combined by the combining optical system 5 onto the screen SCR. As a result, an enlarged image is displayed on the screen SCR.

[0020] The configuration of the light source device 2 will be described below with reference to Fig. 2. Fig. 2 is a schematic diagram showing the configuration of the light source device 2 of this embodiment. As shown in FIG. 2, the light source device 2 includes a light source 10, an afocal optical system 11, a homogenizer optical system 12, a focusing optical system 13, a wavelength conversion device 20, a pickup optical system 30, and a uniform illumination optical system 40.

[0021] The light source 10 is composed of multiple semiconductor lasers 10a that emit blue excitation light E composed of laser light, and multiple collimator lenses 10b. The multiple semiconductor lasers 10a are arranged in an array in a plane perpendicular to the illumination optical axis 100ax. The collimator lenses 10b are arranged in an array in a plane perpendicular to the illumination optical axis 100ax so as to correspond to each semiconductor laser 10a. The collimator lenses 10b convert the excitation light E emitted from the semiconductor lasers 10a corresponding to the collimator lenses 10b into parallel light. The excitation light E in this embodiment corresponds to an example of the "first light" in the present invention.

[0022] The afocal optical system 11 includes, for example, a convex lens 11a and a concave lens 11b. The afocal optical system 11 reduces the beam diameter of the excitation light E emitted from the light source 10 and consisting of a parallel beam.

[0023] The homogenizer optical system 12 includes, for example, a first multi-lens array 12a and a second multi-lens array 12b. The homogenizer optical system 12 uniformly distributes the light intensity of the excitation light on the phosphor layer 21 of the wavelength converter 20, i.e., forms a so-called top-hat distribution. The homogenizer optical system 12, together with the focusing optical system 13, superimposes the multiple small beams emitted from the multiple lenses of the first multi-lens array 12a and the second multi-lens array 12b on the phosphor layer 21 of the wavelength converter 20. This uniformly distributes the light intensity of the excitation light E irradiated onto the phosphor layer 21.

[0024] The focusing optical system 13 includes, for example, a first lens 13a and a second lens 13b. In this embodiment, the first lens 13a and the second lens 13b are each formed of a convex lens. The focusing optical system 13 is disposed in the optical path from the homogenizer optical system 12 to the wavelength converter 20, and focuses the excitation light E to make it incident on the phosphor layer 21 of the wavelength converter 20.

[0025] Next, the configuration of the wavelength converter 20 will be described. Fig. 3 is a cross-sectional view showing the configuration of the wavelength converter 20. Fig. 3 corresponds to a cross section of the wavelength converter 20 cut along a plane including the illumination optical axis 100ax in Fig. 2. Fig. 4 is a plan view showing the configuration of the wavelength converter 20. Fig. 4 is a view of the wavelength converter 20 viewed from a direction perpendicular to the illumination optical axis 100ax in Fig. 2.

[0026] 3, a wavelength conversion device 20 of this embodiment includes a phosphor layer 21, a light-transmitting substrate 22, a dichroic film 23, an anti-reflection film 24, a concave-convex structure 25, and a rotation driver 29. In this embodiment, the phosphor layer 21 corresponds to an example of the "wavelength conversion layer" of the present invention.

[0027] The rotation drive unit 29 is composed of a motor. The rotation drive unit 29 has a rotation shaft 29a that can rotate around a rotation axis O, which is an imaginary axis. The rotation shaft 29a supports the light-transmitting substrate 22 so that the substrate 22 can rotate. 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 approaching the rotation axis O is referred to as the "radially inner side," and the side of the radial direction away from the rotation axis O is referred to as the "radially outer side."

[0028] The light-transmitting substrate 22 has a first surface 22a on which the phosphor layer 21 is provided, and a second surface 22b opposite to the first surface 22a. The light-transmitting substrate 22 is made of a light-transmitting disk-shaped base material such as alumina, sapphire, or glass.

[0029] The phosphor layer 21 converts the excitation light E that passes through the light-transmitting substrate 22 and enters it into fluorescence Y in a yellow wavelength band that is different from the blue wavelength band. The phosphor layer 21 of this embodiment is formed in a ring shape around the rotation axis O on the first surface 22a of the disc-shaped light-transmitting substrate 22. In other words, the phosphor layer 21 is provided in an annular shape around the rotation axis O. The fluorescence Y of this embodiment corresponds to an example of the "second light" of the present invention.

[0030] The phosphor layer 21 generates heat when emitting the fluorescence Y. If the temperature of the phosphor layer 21 becomes too high, the wavelength conversion efficiency of the fluorescence Y may decrease, and the amount of emitted fluorescence Y may decrease. In the wavelength converter 20 of this embodiment, the phosphor layer 21 rotates together with the light-transmitting substrate 22, so that the incident position of the excitation light E on the phosphor layer 21 can be moved over time. This improves the cooling performance of the phosphor layer 21, thereby suppressing a decrease in the fluorescence conversion efficiency that accompanies an increase in the temperature of the phosphor layer 21.

[0031] The excitation light E is incident on the phosphor layer 21 from the back surface 21a facing the light-transmitting substrate 22, and the phosphor layer 21 emits the fluorescence Y from the front surface 21b. The wavelength converter 20 of this embodiment is a transmissive wavelength converter that emits the illumination light WL containing the fluorescence Y from the front surface 21b opposite to the back surface 21a of the phosphor layer 21 where the excitation light E is incident.

[0032] The phosphor layer 21 is a wavelength conversion member containing a ceramic phosphor made of a polycrystalline phosphor. The wavelength band of the fluorescence Y is, for example, a yellow wavelength band of 490 to 750 nm. In other words, the fluorescence Y is yellow fluorescence containing a red light component and a green light component.

[0033] Phosphor layer 21 may contain a single crystal phosphor instead of a polycrystalline phosphor, or may be made of a material in which a large number of phosphor particles are dispersed in a binder made of glass or resin.

[0034] Specifically, the material of the phosphor layer 21 in this embodiment includes, for example, an yttrium-aluminum-garnet (YAG) phosphor. Taking YAG:Ce, which contains cerium (Ce) as an activator, as an example, the material of the phosphor layer 21 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.

[0035] The dichroic film 23 is provided on the first surface 22a of the light-transmitting substrate 22. Specifically, the dichroic film 23 is provided between the light-transmitting substrate 22 and the phosphor layer 21. The dichroic film 23 has a size that overlaps with the phosphor layer 21 in a planar view. Therefore, the dichroic film 23 is formed in a position on the first surface 22a of the light-transmitting substrate 22 that corresponds to the region where the phosphor layer 21 is disposed, and is not formed in a region where the phosphor layer 21 is not disposed.

[0036] The dichroic film 23 has optical properties of transmitting the excitation light E and reflecting the fluorescence Y. The dichroic film 23 is formed, for example, of a dielectric multilayer film. That is, the phosphor layer 21 is provided on the first surface 22a side of the light-transmitting substrate 22 with the dichroic film 23 interposed therebetween.

[0037] The excitation light E is incident on the second surface 22b of the light-transmitting substrate 22, which is opposite to the dichroic film 23. The anti-reflection film 24 is provided on the second surface 22b of the light-transmitting substrate 22. The anti-reflection film 24 is formed of, for example, an AR coating. The anti-reflection film 24 suppresses reflection of the excitation light E at the interface between the second surface 22b of the light-transmitting substrate 22 and the air layer. This allows the excitation light E to efficiently enter the light-transmitting substrate 22 from the second surface 22b via the anti-reflection film 24. Note that the anti-reflection film 24 is not an essential component of the wavelength conversion device 20, and may be omitted as necessary.

[0038] The uneven structure 25 is provided on the first surface 22a side of the light-transmitting substrate 22. The uneven structure 25 is provided in an area of ​​the first surface 22a that does not overlap with the phosphor layer 21. In the present embodiment, the uneven structure 25 is disposed in an area of ​​the first surface 22a where the dichroic film 23 is not provided. This configuration allows the fluorescence Y to be efficiently incident on the uneven structure 25 from the first surface 22a.

[0039] The concave-convex structure 25 of this embodiment is a rough surface formed by roughening a portion of the first surface 22a. With this configuration, the concave-convex structure 25 can be easily formed at a desired position on the first surface 22a by processing the first surface 22a. The surface roughness of the rough surface that constitutes the concave-convex structure 25 is preferably, for example, 0.0059 μm or more, and more preferably 0.0096 μm or more, in arithmetic mean roughness (Ra).

[0040] In the present embodiment, excitation light E is incident on the phosphor layer 21 from the back surface 21a facing the light-transmitting substrate 22, and fluorescence Y is emitted from the front surface 21b. The phosphor layer 21 converts the excitation light E in the blue wavelength band into fluorescence Y in a yellow wavelength band different from the blue wavelength band. The phosphor layer 21 transmits and emits a portion of the excitation light E1 that has not been wavelength-converted, in addition to the fluorescence Y. As a result, the wavelength conversion device 20 emits white illumination light WL containing the excitation light E1 and the fluorescence Y from the surface 21b of the phosphor layer 21.

[0041] A portion of the fluorescence Y generated in the phosphor layer 21 travels toward the light-transmitting substrate 22 and is incident on the dichroic film 23 provided on the first surface 22a. The fluorescence Y incident on the dichroic film 23 is mostly reflected in the direction opposite to the light-transmitting substrate 22 and is emitted from the surface 21b of the phosphor layer 21.

[0042] On the other hand, because the fluorescence Y is unpolarized light, the P-polarized component of the fluorescence Y incident on the dichroic film 23 that is incident at an angle close to the Brewster angle passes through the dichroic film 23 and enters the light-transmitting substrate 22. The leaked fluorescence that has entered the light-transmitting substrate 22 in this way propagates within the light-transmitting substrate 22 by total reflection and may be emitted to the outside from the side surface of the light-transmitting substrate 22, causing a loss.

[0043] In contrast, the wavelength converter 20 of the present embodiment includes the uneven structure 25 provided on the first surface 22a side of the light-transmitting substrate 22, and therefore the leaking fluorescence Y1 propagating within the light-transmitting substrate 22 is incident on the uneven structure 25. Because the uneven structure 25 is a rough surface facing in various directions different from the first surface 22a, the leaking fluorescence Y1 incident on the uneven structure 25 is incident on the surface of the uneven structure 25 at an angle smaller than the critical angle, and is therefore emitted to the outside without being totally reflected at the interface with the air layer.

[0044] 4, the concave-convex structure 25 is provided on both the radially inner side and the radially outer side of the annular phosphor layer 21 in the radial direction of the first surface. That is, the concave-convex structure 25 is disposed on both sides of the phosphor layer 21 in the radial direction of the first surface 22a of the disc-shaped light-transmitting substrate 22. The leaked fluorescence Y1 that has leaked into the light-transmitting substrate 22 propagates in all directions within the light-transmitting substrate 22. With this configuration, the concave-convex structure 25 can efficiently emit the leaked component of the fluorescence Y propagating radially within the light-transmitting substrate 22 to the outside of the light-transmitting substrate 22.

[0045] As shown in FIG. 2, the illumination light WL emitted from the wavelength conversion device 20 enters the pickup optical system 30. The pickup optical system 30 includes, for example, a first collimating lens 31 and a second collimating lens 32. The pickup optical system 30 is a collimating optical system that approximately collimates the illumination light WL emitted from the wavelength conversion device 20. The first collimating lens 31 and the second collimating lens 32 are each composed of a convex lens. The light collimated by the pickup optical system 30 enters the uniform illumination optical system 40.

[0046] The uniform illumination optical system 40 includes a first lens array 41, a second lens array 42, a polarization conversion element 43, and a superimposing lens 44.

[0047] The first lens array 41 has a plurality of first lenses 41a for dividing the illumination light WL from the light source device 2 into a plurality of partial light beams. The plurality of first lenses 41a are arranged in a matrix in a plane perpendicular to the illumination optical axis 100ax.

[0048] The second lens array 42 has a plurality of second lenses 42a corresponding to the 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.

[0049] The second lens array 42, together with the superimposing lens 44, forms images of the first lenses 41a of the first lens array 41 near the image forming areas of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, respectively.

[0050] The polarization conversion element 43 converts the light emitted from the second lens array 42 into one type of linearly polarized light. The polarization conversion element 43 includes, for example, a polarization separation film and a phase difference plate (not shown).

[0051] The superimposing lens 44 condenses the partial light beams emitted from the polarization conversion element 43 and superimposes them near the image forming areas of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B.

[0052] As described above, the light source device 2 of this embodiment includes: a light source 10 that emits excitation light E; a phosphor layer 21 that converts the excitation light E incident from the light source 10 into fluorescence Y of a yellow wavelength band different from the excitation light E; a light-transmitting substrate 22 that has a first surface 22a and a second surface 22b opposite to the first surface 22a and on which the phosphor layer 21 is provided on the first surface 22a side; a dichroic film 23 that is provided between the first surface 22a of the light-transmitting substrate 22 and the phosphor layer 21 and that transmits the excitation light E and reflects the fluorescence Y; and an uneven structure 25 that is provided on the first surface 22a side of the light-transmitting substrate 22.

[0053] According to the light source device 2 of the present embodiment, even if part of the fluorescence Y passes through the dichroic film 23 and leaks into the light-transmitting substrate 22, the leaking fluorescence Y1 that has leaked into the light-transmitting substrate 22 can be extracted as part of the illumination light WL from the first surface 22a side of the light-transmitting substrate 22 by the concavo-convex structure 25. Therefore, the light source device 2 of the present embodiment can increase the amount of fluorescence Y that can be used as illumination light WL, and can generate bright illumination light WL by improving the light utilization efficiency of the fluorescence Y.

[0054] The projector 1 of this embodiment includes a light source device 2, light modulation devices 4R, 4G, and 4B that modulate the light incident from the light source device 2, and a projection optical device 6 that projects the light modulated by the light modulation devices 4R, 4G, and 4B.

[0055] According to the projector 1 of this embodiment, by modulating the bright illumination light WL incident from the light source device 2, it is possible to project a bright image.

[0056] (First Modification) Next, a first modified example of the present invention will be described. In this modified example, the configuration of the concave-convex structure of the wavelength conversion device is different from that of the above embodiment, but the other configurations are the same. Therefore, the configuration of the concave-convex structure will be mainly described below, and a description of the other configurations will be omitted.

[0057] 5 is a cross-sectional view showing the configuration of a wavelength converter 120 of this modified example. FIG. 5 is a cross-sectional view corresponding to FIG. As shown in FIG. 5, a wavelength converter 120 of this modified example includes a phosphor layer 21, a light-transmitting substrate 22, a dichroic film 23, an anti-reflection film 24, a concave-convex structure 125, and a rotation driver 29.

[0058] The concave-convex structure 125 of this modification is configured by a first optical member 130 having a light incident surface 131, a reflecting surface 132, and a light exit surface 133. The first optical member 130 is, for example, a compound parabolic concentrator (CPC). In this modification, the first optical members 130 are provided on the radially inner and outer sides of the first surface 22a of the light-transmitting substrate 22, respectively.

[0059] The light incident surface 131 is a portion onto which the fluorescence Y propagating within the light-transmitting substrate 22 is incident. Because the uneven structure 125 of this modified example is formed separately from the light-transmitting substrate 22, the light incident surface 131 abuts against the first surface 22a. If the uneven structure 125 is formed integrally with the light-transmitting substrate 22, the light incident surface 131 is formed by a part of the first surface 22a. The reflecting surface 132 is a surface that reflects the fluorescence Y incident from the light incident surface 131, and is formed by a plurality of side surfaces that are in contact with the surface that forms the light incident surface 131 and the light exit surface 133, respectively. The light exit surface 133 is a surface that exits the fluorescence Y reflected by the reflecting surface 132.

[0060] The cross-sectional area of ​​the first optical member 130 perpendicular to the optical axis 130J that passes through the center of the first optical member 130 gradually increases from the light incident surface 131 toward the light exit surface 133. Therefore, the area of ​​the light exit surface 133 is larger than the area of ​​the light incident surface 131. Furthermore, the width of the reflecting surface 132 in the direction perpendicular to the optical axis 130J gradually increases from the light incident surface 131 toward the light exit surface 133. When the first optical member 130 is viewed from the direction perpendicular to the optical axis 130J, the shape of the reflecting surface 132 is parabolic.

[0061] Instead of a CPC, the first optical member 130 may be a tapered rod in the shape of a truncated quadrangular pyramid, the area of ​​the exit end face of which is larger than the area of ​​the entrance end face.

[0062] In this modification, the leaked fluorescence Y1 that has entered the first optical member 130 having the concave-convex structure 125 changes direction each time it is totally reflected by the reflecting surface 132 while traveling inside the first optical member 130, so that it approaches a direction parallel to the optical axis 130J. In this way, the first optical member 130 converts the emission angle distribution of the leaked fluorescence Y1 that is emitted from the first surface 22a of the light-transmitting substrate 22. Specifically, the first optical member 130 has an angle conversion function that makes the maximum emission angle of the leaked fluorescence Y1 on the light emission surface 133 smaller than the maximum incident angle of the leaked fluorescence Y1 on the light incidence surface 131.

[0063] As described above, according to the wavelength converter 120 of this modified example, the CPC-shaped uneven structure 125 makes it possible to suppress the emission angle of the leaking fluorescence Y1 that has leaked into the light-transmitting substrate 22 and extract it to the outside of the light-transmitting substrate 22. Therefore, suppressing the spread of the leaking fluorescence Y1 allows the fluorescence Y1 to efficiently enter the optical system at the subsequent stage, thereby further improving the light utilization efficiency of the fluorescence Y.

[0064] (Second Modification) Next, a second modified example of the light source device will be described. In this modified example, the configuration of the concave-convex structure of the wavelength conversion device is different from that of the above embodiment, but the other configurations are the same. Therefore, the configuration of the concave-convex structure will be mainly described below, and a description of the other configurations will be omitted.

[0065] 6 is a cross-sectional view showing the configuration of a wavelength converter 220 of this modified example. FIG. 6 is a cross-sectional view corresponding to FIG. As shown in FIG. 6, a wavelength converter 220 of this modified example includes a phosphor layer 21, a light-transmitting substrate 22, a dichroic film 23, an anti-reflection film 24, a concave-convex structure 225, and a rotation driver 29.

[0066] The concave-convex structure 225 of this modified example is configured by a Fresnel lens-shaped second optical member 230 including a plurality of lens surfaces 230a that refract and emit leaked fluorescence Y1, which is a portion of the incident fluorescence Y that has propagated within the light-transmitting substrate 22. The plurality of lens surfaces 230a are arranged concentrically around the rotation axis O of the light-transmitting substrate 22, and have a sawtooth cross-sectional shape. In this modified example, the second optical member 230 is provided radially outward of the first surface 22a of the light-transmitting substrate 22.

[0067] In this modification, the leaking fluorescence Y1 incident on the second optical member 230 having the concave-convex structure 225 is focused by the multiple lens surfaces 230a while traveling inside the second optical member 230, and changes its direction so as to approach a direction parallel to the rotation axis O. In this way, the second optical member 230 can reduce the divergence angle of the leaking fluorescence Y1 emitted from the first surface 22a of the light-transmitting substrate 22.

[0068] As described above, according to the wavelength converter 220 of this modified example, the Fresnel lens-shaped concave-convex structure 225 can suppress the spread of the leaking fluorescence Y1 that has leaked into the light-transmitting substrate 22 and extract the leaking fluorescence Y1 to the outside of the light-transmitting substrate 22. Therefore, similar to the configuration of the first modified example, suppressing the spread of the leaking fluorescence Y1 allows the fluorescence Y to be efficiently incident on the optical system at the subsequent stage, thereby improving the light utilization efficiency of the fluorescence Y.

[0069] Furthermore, because a Fresnel lens-shaped member is used as the second optical member 230, it is possible to prevent an increase in size in the direction along the illumination optical axis 100ax compared to a configuration in which a plano-convex lens-shaped member is disposed on the first surface 22a of the light-transmitting substrate 22. Therefore, it is possible to improve the light utilization efficiency of the fluorescence Y while preventing an increase in size of the device configuration.

[0070] Note that a second optical member 230 may be further provided radially inward of the first surface 22a of the light-transmitting substrate 22. In this case, the orientation of the multiple lens surfaces (sawtooth) of the second optical member 230 disposed radially inward of the light-transmitting substrate 22 is provided symmetrically with respect to the multiple lens surfaces 230a of the second optical member 230 disposed radially outward, with the phosphor layer 21 as the reference. This allows the leaked fluorescence that has leaked from the phosphor layer 21 to the radially inward side of the light-transmitting substrate 22 to be efficiently emitted from the first surface 22a.

[0071] 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, although the wavelength converters of the above embodiments and modifications employ a rotation type in which the light-transmitting substrate 22 rotates, the present invention is also applicable to a fixed type wavelength converter in which the light-transmitting substrate 22 does not rotate.

[0072] Furthermore, in the wavelength conversion devices of the above-described embodiment and modified examples, an uneven structure is disposed in an area of ​​the first surface 22a where the dichroic film 23 is not provided. However, the dichroic film 23 may cover the entire first surface 22a, and the uneven structure may be provided on the first surface 22a via the dichroic film. That is, the uneven structure does not have to be formed directly on the first surface 22a. Furthermore, the dichroic film 23 may be provided so as to cover the uneven structure 25 shown in FIG. 3.

[0073] In addition, the specific descriptions of the shape, number, arrangement, material, etc. of each component of the light source device and the projector are not limited to the above-described embodiments and can be changed as appropriate.

[0074] A summary of this disclosure is provided below.

[0075] (Appendix 1) a light source that emits a first light; a wavelength conversion layer that converts the first light incident from the light source into second light having a wavelength band different from that of the first light; a light-transmitting substrate having a first surface and a second surface opposite to the first surface, the wavelength conversion layer being provided on the first surface side; a dichroic film provided between the first surface of the light-transmitting substrate and the wavelength conversion layer, the dichroic film transmitting the first light and reflecting the second light; a concave-convex structure provided on the first surface side of the light-transmitting substrate, Light source device.

[0076] With this light source device, by satisfying the Brewster angle, a portion of the second light that has passed through the dichroic film and leaked into the light-transmitting substrate can be extracted as part of the illumination light from the first surface side of the light-transmitting substrate 22 by the concavo-convex structure. Therefore, the light source device with this configuration can increase the amount of second light that can be used as illumination light, and can generate bright illumination light by improving the utilization efficiency of the second light.

[0077] (Appendix 2) The uneven structure is a rough surface formed by roughening a part of the first surface. 10. The light source device of claim 1.

[0078] According to this configuration, the concave-convex structure can be easily formed at a desired position on the first surface by processing the first surface.

[0079] (Appendix 3) the concavo-convex structure is composed of a first optical member having a light incident surface on which the second light propagated within the light-transmitting substrate is incident, a reflecting surface that reflects the second light incident from the light incident surface, and a light exit surface that exits the second light reflected by the reflecting surface. 10. The light source device according to claim 1 or 2.

[0080] According to this configuration, the second light leaking into the light-transmitting substrate can be extracted to the outside of the light-transmitting substrate with a reduced exit angle due to the concavo-convex structure. Therefore, by reducing the spread of the second light, the second light can efficiently enter the optical system at the subsequent stage, thereby further increasing the utilization efficiency of the second light.

[0081] (Appendix 4) the concave-convex structure is composed of a second optical member having a Fresnel lens shape including a plurality of lens surfaces that refract and emit the second light that propagates through the light-transmitting substrate and is incident thereon. 10. The light source device according to claim 1 or 2.

[0082] According to this configuration, the second light leaking into the light-transmitting substrate can be extracted to the outside of the light-transmitting substrate while suppressing the spread of the second light due to the Fresnel lens-shaped concave-convex structure. Therefore, suppressing the spread of the second light allows the second light to efficiently enter the downstream optical system, thereby improving the light utilization efficiency of the second light. Furthermore, because a Fresnel lens-shaped second optical member is used, the size in the direction along the illumination optical axis can be reduced compared to when a plano-convex lens-shaped member is used. Therefore, the light utilization efficiency of the second light can be improved while suppressing the size of the device configuration.

[0083] (Appendix 5) the concave-convex structure is disposed in an area of ​​the first surface where the dichroic film is not provided. 5. A light source device according to any one of claims 1 to 4.

[0084] According to this configuration, the second light can be efficiently incident on the concave-convex structure from the first surface.

[0085] (Appendix 6) the light-transmitting substrate is disk-shaped; the wavelength conversion layer is annular; the concave-convex structure is provided on a radial inner side and a radial outer side of the wavelength conversion layer in a radial direction of the first surface, 6. A light source device according to any one of claims 1 to 5.

[0086] According to this configuration, the concave-convex structure can efficiently emit the leaking component of the second light propagating in the radial direction within the light-transmitting substrate to the outside of the light-transmitting substrate.

[0087] (Appendix 7) a light source device according to any one of Supplementary Note 1 to Supplementary Note 6; a light modulation device that modulates light incident from the light source device; a projection optical device that projects the light modulated by the light modulation device; Equipped with projector.

[0088] According to a projector having this configuration, it is possible to project a bright image by modulating the bright illumination light incident from the light source device. [Explanation of symbols]

[0089] 1...projector, 2...light source device, 4B, 4G, 4R...light modulation device, 6...projection optical device, 10...light source, 22...light-transmitting substrate, 22a...first surface, 22b...second surface, 23...dichroic film, 25, 125, 225...concave-convex structure, 130...first optical member, 131...light incident surface, 132...reflecting surface, 133...light exit surface, 230...second optical member, 230a...lens surface, E...excitation light (first light), Y...fluorescence (second light).

Claims

1. a light source that emits a first light; a wavelength conversion layer that converts the first light incident from the light source into second light having a wavelength band different from that of the first light; a light-transmitting substrate having a first surface and a second surface opposite to the first surface, the wavelength conversion layer being provided on the first surface side; a dichroic film provided between the first surface of the light-transmitting substrate and the wavelength conversion layer, the dichroic film transmitting the first light and reflecting the second light; a concave-convex structure provided on the first surface side of the light-transmitting substrate, Light source device.

2. The uneven structure is a rough surface formed by roughening a part of the first surface. The light source device according to claim 1 .

3. the concavo-convex structure is composed of a first optical member having a light incident surface on which the second light propagated within the light-transmitting substrate is incident, a reflecting surface that reflects the second light incident from the light incident surface, and a light exit surface that exits the second light reflected by the reflecting surface. The light source device according to claim 1 .

4. the concave-convex structure is formed by a second optical member having a Fresnel lens shape including a plurality of lens surfaces that refract and emit the second light that propagates through the light-transmitting substrate and is incident thereon; The light source device according to claim 1 .

5. the concave-convex structure is disposed in a region of the first surface where the dichroic film is not provided; The light source device according to claim 1 .

6. the light-transmitting substrate is disk-shaped; the wavelength conversion layer is annular; the concave-convex structure is provided on a radially inner side and a radially outer side of the wavelength conversion layer in a radial direction of the first surface, The light source device according to claim 1 .

7. The light source device according to any one of claims 1 to 6, a light modulation device that modulates light incident from the light source device; a projection optical device that projects the light modulated by the light modulation device; Equipped with projector.

Images