Light source device and projector

Abstract

To provide a light source device and a projector that can improve luminous efficacy.SOLUTION: A light source device comprises: a first laser light-emitting element that emits first light in a first wavelength range; a wavelength conversion element that converts the first light into second light in a second wavelength range; a substrate that has a first support part supporting the first laser light-emitting element, and a second support part supporting the wavelength conversion element; and a first optical element that is arranged between the first laser light-emitting element and the wavelength conversion element, and guides the first light emitted from the first laser light-emitting device to the wavelength conversion element. The first optical element has a first incident surface which faces the first laser light-emitting element and on which the first light emitted from the first laser light-emitting element is incident, a first reflection surface that reflects the first light incident from the first incident surface to bend a light path of the first light, and a first emission surface that faces the wavelength conversion element and emits the first light reflected on the first reflection surface toward the wavelength conversion element. The first incident surface, first reflection surface, and first emission surface intersect one another.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] Patent Document 1 below discloses a light source device having a phosphor provided on a support surface of a substrate and an excitation light source, causing excitation light emitted from the excitation light source parallel to the support surface to enter the phosphor, and taking out fluorescence emitted from the phosphor through a translucent window.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above light source device, since the phosphor is excited by the excitation light emitted from the excitation light source along the support surface of the base material, the excitation light cannot efficiently enter the phosphor, and there is a problem that bright fluorescence cannot be generated due to a decrease in the fluorescence conversion efficiency.

Means for Solving the Problems

[0005] To solve the above problems, according to one aspect of the present invention, a light source device is provided comprising: a substrate having a first laser light-emitting element that emits first light in a first wavelength band; a wavelength conversion element that converts the first light into second light in a second wavelength band different from the first wavelength band; a first support portion that supports the first laser light-emitting element; and a second support portion that supports the wavelength conversion element; and a first optical element disposed on the optical path of the first light between the first laser light-emitting element and the wavelength conversion element, which guides the first light emitted from the first laser light-emitting element to the wavelength conversion element, wherein the first optical element has a first incident surface facing the first laser light-emitting element and into which the first light emitted from the first laser light-emitting element is incident; a first reflective surface that reflects the first light incident from the first incident surface and bends the optical path of the first light; and a first output surface facing the wavelength conversion element and emitting the first light reflected by the first reflective surface toward the wavelength conversion element, wherein the first incident surface, the first reflective surface, and the first output surface intersect with each other.

[0006] A second aspect of the present invention provides a projector comprising a light source device according to the first aspect of the present invention, an optical modulator for modulating light from the light source device, and a projection optical device for projecting light modulated by the optical modulator. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows a schematic configuration of a projector according to the embodiment. [Figure 2] This is a schematic diagram of the lighting system. [Figure 3] This is a plan view of the light source device. [Figure 4] This is a cross-section taken along the line IV-IV in Figure 3. [Figure 5] This is a plan view of the prism member according to the first modified example. [Figure 6] This is a plan view of the prism member according to the second modified example. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Please note that the drawings used in the following explanation may be enlarged for convenience to make the features easier to understand, and the dimensional ratios of each component may not be the same as in reality.

[0009] An example of a projector according to this embodiment will be described. Figure 1 shows a schematic configuration of the projector according to this embodiment. As shown in Figure 1, the projector 1 of this embodiment is a projection-type image display device that displays a color image on a screen SCR. The projector 1 comprises a color separation optical system 3, optical modulators 4R, 4G, and 4B, a combining optical system 5, a projection optical system 6, and an illumination device 2.

[0010] The color separation optical system 3 separates the white illumination light WL from the illumination device 2 into red light LR, green light LG, and blue light LB. The color separation optical system 3 comprises a first dichroic mirror 7a and a second dichroic mirror 7b, a first reflective mirror 8a, a second reflective mirror 8b, and a third reflective mirror 8c, and a first relay lens 9a and a second relay lens 9b.

[0011] The first dichroic mirror 7a separates the illumination light WL from the illumination device 2 into red light LR and other light, namely green light LG and blue light LB. The first dichroic mirror 7a transmits the separated red light LR and reflects the other light. The second dichroic mirror 7b reflects the green light LG and transmits the blue light LB.

[0012] The first reflective mirror 8a reflects the red light LR toward the optical modulator 4R. The second reflective mirror 8b and the third reflective mirror 8c guide the blue light LB toward the optical modulator 4B. The green light LG is reflected from the second dichroic mirror 7b toward the optical modulator 4G.

[0013] The first relay lens 9a is disposed downstream of the second dichroic mirror 7b in the optical path of the blue light LB. The second relay lens 9b is disposed downstream of the second reflection mirror 8b in the optical path of the blue light LB.

[0014] The light modulation device 4R modulates the red light LR according to the image information and forms image light corresponding to the red light LR. The light modulation device 4G modulates the green light LG according to the image information and forms image light corresponding to the green light LG. The light modulation device 4B modulates the blue light LB according to the image information and forms image light corresponding to the blue light LB.

[0015] For example, transmissive liquid crystal panels are used for the light modulation devices 4R, 4G, and 4B. Polarizing plates (not shown) are respectively disposed on the incident side and the emission side of the liquid crystal panel, and are configured to allow only linearly polarized light in a specific direction to pass through.

[0016] Field lenses 10R, 10G, and 10B are respectively disposed on the incident sides of the light modulation devices 4R, 4G, and 4B. The field lenses 10R, 10G, and 10B collimate the principal rays of the red light LR, green light LG, and blue light LB incident on the respective light modulation devices 4R, 4G, and 4B.

[0017] The combining optical system 5 combines the image light corresponding to the red light LR, green light LG, and blue light LB when the image light emitted from the light modulation devices 4R, 4G, and 4B is incident, and emits the combined image light toward the projection optical device 6. For example, a cross dichroic prism is used for the combining optical system 5.

[0018] The projection optical device 6 is composed of a plurality of lenses. The projection optical device 6 enlarges and projects the image light combined by the combining optical system 5 toward the screen SCR. Thereby, an image is displayed on the screen SCR.

[0019] Figure 2 is a schematic configuration diagram of the lighting device 2. As shown in FIG. 2, the lighting device 2 includes a light source device 20, a pickup optical system 34, an integrator optical system 35, a polarization conversion element 36, and a superimposing lens 37.

[0020] The light source device 20 emits white illumination light WL toward the pickup optical system 34.

[0021] The illumination light WL parallelized by the pickup optical system 34 enters the integrator optical system 35. The integrator optical system 35 is composed of, for example, a first lens array 35a and a second lens array 35b. The first lens array 35a includes a plurality of first small lenses 35am, and the second lens array 35b includes a plurality of second small lenses 35bm.

[0022] The first lens array 35a separates the illumination light WL into a plurality of small light beams. The first small lens 35am forms an image of the small light beam on the corresponding second small lens 35bm. The integrator optical system 35 cooperates with the superimposing lens 37 described later to uniformize the illuminance distribution in the image formation regions of the optical modulation devices 4R, 4G, and 4B shown in FIG. 1, which are the illuminated regions.

[0023] The illumination light WL that has passed through the integrator optical system 35 enters the polarization conversion element 36. The polarization conversion element 36 is composed of, for example, a polarization separation film and a retardation plate (1 / 2 wavelength plate). The polarization conversion element 36 converts the polarization direction of the fluorescence YL into one polarization component.

[0024] The illumination light WL that has passed through the polarization conversion element 36 enters the superimposing lens 37. The illumination light WL emitted from the superimposing lens 37 enters the color separation optical system 3. The superimposing lens 37 uniformly illuminates by superimposing the plurality of small light beams constituting the illumination light WL on each other in the illuminated regions of the optical modulation devices 4R and 4G, that is, the image formation regions.

[0025] Hereinafter, the configuration of the light source device 20 will be described in detail. Figure 3 is a plan view of the light source device 20. Figure 3 is a view of the light source device 20 from a direction along the optical axis ax (Z-axis direction). In the following drawings, the various components of the light source device 20 will be explained using the XYZ coordinate system as needed. The Z-axis is an axis parallel to the optical axis ax of the light source device 20, the X-axis is perpendicular to the optical axis ax and parallel to the normal of the substrate 21 that constitutes the light source device 20, and the Y-axis and Z-axis are perpendicular to each other and are also perpendicular to the X-axis. Note that the optical axis ax of the light source device 20 coincides with the illumination optical axis ax1 of the illumination device 2 shown in Figure 2.

[0026] As shown in Figure 3, the light source device 20 comprises a substrate 21, a plurality of laser light-emitting elements 22, a wavelength conversion element 24, a prism member 25, and a reflective member 30 (see Figure 4, described later).

[0027] The substrate 21 supports multiple laser light-emitting elements 22 and wavelength conversion elements 24. The substrate 21 is, for example, a metal plate with excellent heat dissipation properties, such as aluminum or copper.

[0028] When viewed from a plan view (hereinafter simply referred to as a plan view) from the Z-axis direction along the optical axis ax, the multiple laser light-emitting elements 22 are arranged around the prism member 25. The multiple laser light-emitting elements 22 are arranged to extend radially around the prism member 25. The multiple laser light-emitting elements 22 are arranged so that pairs of elements face each other across the optical axis ax.

[0029] In this embodiment, the plurality of laser light-emitting elements 22 include a first laser light-emitting element 22a and a second laser light-emitting element 22b. The first laser light-emitting element 22a and the second laser light-emitting element 22b are arranged on the substrate 21 so as to face each other across the optical axis ax. The first laser light-emitting element 22a is positioned on the -Y side with respect to the optical axis ax, and the second laser light-emitting element 22b is positioned on the +Y side with respect to the optical axis ax.

[0030] Figure 4 is a cross-sectional view of the light source device 20. Figure 4 is a cross-section taken along the line IV-IV in Figure 3, and is a cross-sectional view of the light source device 20 taken from a plane that includes the optical axis ax and is perpendicular to the XY plane. Note that Figure 4 is a cross-sectional view including the first laser light source 22a and the second laser light source 22b among the multiple laser light source 22.

[0031] The base material 21 is a plate material having a surface 210 and a back surface 211, and supports a plurality of laser light-emitting elements 22, wavelength conversion elements 24 and a prism member 25 on the surface 210 side. The base material 21 has a first support portion 21a that supports the plurality of laser light-emitting elements 22, a second support portion 21b that supports the wavelength conversion elements 24, a third support portion 21c that supports the prism member 25, and a recess 213 that accommodates the wavelength conversion elements 24. The substrate 21 functions as a heat dissipation member that releases heat from the multiple laser light-emitting elements 22, wavelength conversion elements 24, and prism members 25.

[0032] The third support portion 21c is provided in the center of the surface 210 of the base material 21. The first support portion 21a is provided around the third support portion 21c on the surface 210 of the base material 21.

[0033] As shown in Figure 3, the second support portion 21b is provided in a position that overlaps with the third support portion 21c when viewed from above. The second support portion 21b is a recess 213 in which the wavelength conversion element 24 is housed. That is, the recess 213 is formed in a position that overlaps with a part of the third support portion 21c in the base material 21 when viewed from above.

[0034] The first support portion 21a has a first support surface 21a1 that supports a plurality of laser light-emitting elements 22. The third support portion 21c has a third support surface 21c1 that supports a prism member 25. In this embodiment, the first support surface 21a1 and the third support surface 21c1 are composed of a part of the surface 210 of the base material 21. That is, the first support surface 21a1 and the third support surface 21c1 are on the same plane. However, the first support surface 21a1 and the third support surface 21c1 may be on different planes in the Z-axis direction. For example, the third support surface 21c1 may be recessed relative to the first support surface 21a1. In this case, it becomes easier to position the prism member 25 within the recessed third support surface 21c1 relative to the first support surface 21a1.

[0035] In this embodiment, since the first support surface 21a1 supporting each laser light-emitting element 22 is a flat surface, the process of mounting each laser light-emitting element 22 onto the substrate 21 is simplified. As a result, each laser light-emitting element 22 can be mounted on the substrate 21 with high precision, making it easier to align the excitation light E emitted from each laser light-emitting element 22 with the prism member 25. Therefore, the positional accuracy of the irradiation spot of the excitation light E formed on the wavelength conversion element 24 can be improved.

[0036] The second support portion 21b has a second support surface 21b1 that supports the wavelength conversion element 24. The second support surface 21b1 is the bottom surface of a recess 213 formed on the surface 210 of the base material 21. Therefore, the second support surface 21b1 is located on the back surface 211 side of the base material 21 relative to the first support surface 21a1 and the third support surface 21c1. In other words, the second support surface 21b1 is a recessed surface relative to the surface 210 of the base material 21.

[0037] In this embodiment, the prism member 25 is fixed to the third support portion 21c via a reflective member 30. The reflective member 30 reflects the excitation light E and the fluorescence YL described later, and is composed of, for example, an Ag paste film. The reflective member 30 is provided in a region of the first emission surface 28A that does not face the wavelength conversion element 24.

[0038] In this embodiment, a gap S is provided between the wavelength conversion element 24 supported by the second support portion 21b and the prism member 25 supported by the third support portion 21c. In other words, the wavelength conversion element 24 and the prism member 25 are not in contact, and an air layer A is provided in the gap S between the wavelength conversion element 24 and the prism member 25.

[0039] Next, the configuration of the laser light-emitting element 22 will be described. Each laser light-emitting element 22 has the same configuration. Each laser light-emitting element 22 includes a light-emitting section 220 and a submount 221. The light-emitting section 220 emits excitation light (first light) E in the first wavelength band. The first wavelength band is, for example, a wavelength band from blue to violet, ranging from 400 nm to 480 nm, with a peak wavelength of, for example, 455 nm.

[0040] The submount 221 is made of a ceramic material such as aluminum nitride or alumina. The submount 221 relieves thermal stress caused by the difference in the coefficient of linear expansion between the base material 21 and the light-emitting part 220. The submount 221 is joined to the first support part 21a of the base material 21 by a bonding material such as silver solder or gold-tin solder.

[0041] Each of the laser light-emitting elements 22 is supported on a first support portion 21a of the substrate 21 so as to emit excitation light E along the surface 210 of the substrate 21. The excitation light E emitted from each laser light-emitting element 22 is incident on the prism member 25.

[0042] The prism member 25 is positioned in the optical path of the excitation light E between each laser light-emitting element 22 and the wavelength conversion element 24, and guides the excitation light E emitted from each laser light-emitting element 22 to the wavelength conversion element 24.

[0043] The wavelength conversion element 24 includes a wavelength conversion layer 240 and a reflective layer 241 provided on the side opposite to the prism member 25 relative to the wavelength conversion layer 240. The wavelength conversion layer 240 has a front surface 240a and a back surface 240b. The reflective layer 241 is provided on the back surface 240b of the wavelength conversion layer 240.

[0044] The wavelength conversion layer 240 contains a phosphor that converts excitation light E into fluorescence (second light) YL in a second wavelength band different from the first wavelength band. The second wavelength band is, for example, the yellow wavelength band of 550 to 640 nm. As such a phosphor, for example, a YAG (yttrium aluminum garnet) phosphor can be used. The phosphor-forming material may be one type, or a mixture of particles formed using two or more types of materials may be used as the phosphor.

[0045] The surface 240a of the wavelength conversion layer 240 corresponds to the light incident surface in the wavelength conversion element 24. The wavelength conversion layer 240 emits fluorescent YL from its surface 240a by wavelength conversion of the excitation light E incident on its surface 240a. In addition, a portion of the excitation light E is scattered on or within the surface 240a of the wavelength conversion layer 240 and emitted from the surface 240a without being converted into fluorescent YL. Therefore, the surface 240a of the wavelength conversion layer 240 also corresponds to the light emission surface in the wavelength conversion element 24.

[0046] A portion of the fluorescent yellow light (YL) travels toward the back surface 240b of the wavelength conversion layer 240. In this embodiment, the fluorescent yellow light (YL) can be reflected toward the front surface 240a by the reflective layer 241 provided on the back surface 240b of the wavelength conversion layer 240. The wavelength conversion element 24 in this embodiment is a reflective type wavelength conversion element that emits fluorescent YL from the surface 240a into which the excitation light E is incident.

[0047] As shown in Figure 3, the prism member 25 has a circular shape and an appearance in which the upper surface of a frustocone has been removed in a conical shape. The prism member 25 is made of optical glass such as quartz or BK7. The central axis 25C of the prism member 25 coincides with the optical axis ax of the light source device 20. As shown in Figure 4, the prism member 25 is supported by the third support portion 21c of the base material 21 so as to cover the wavelength conversion element 24 which is located in the recess 213 of the base material 21.

[0048] The prism member 25 has an incident surface (first surface) 26, a reflective surface (second surface) 27, an exit surface (third surface) 28, a first optical layer 31, and a second optical layer 32. The incident surface 26, the reflective surface 27, and the exit surface 28 are surfaces that intersect each other.

[0049] As shown in Figure 3, the incident surface 26 includes a first conical surface M1 whose apex is on the opposite side (+Z side) from the wavelength conversion element 24 relative to the prism member 25. The incident surface 26 is the surface that faces each laser light-emitting element 22 and is incident on by the excitation light E emitted from each laser light-emitting element 22.

[0050] As shown in Figure 3, the reflective surface 27 is located inside the first conical surface M1 and includes a second conical surface M2 whose apex is on the substrate 21 side. The reflective surface 27 is the surface that reflects the excitation light E incident from the incident surface 26 and bends the optical path of the excitation light E toward the wavelength conversion element 24 side.

[0051] The emission surface 28 faces the wavelength conversion element 24 and is the surface that emits the excitation light E, which is reflected by the reflection surface 27 and faces the wavelength conversion element 24, toward the wavelength conversion element 24.

[0052] The prism member 25 in this embodiment is composed of multiple parts 125, each corresponding to a plurality of laser light-emitting elements 22. In this embodiment, each part 125 is integrally molded. In other words, the prism member 25 in this embodiment is a single prism member.

[0053] The multiple parts 125 include a first part (first optical element) 125A corresponding to the first laser light-emitting element 22a, and a second part (second optical element) 125B corresponding to the second laser light-emitting element 22b.

[0054] The first part 125A has a first incident surface 26A, a first reflection surface 27A, and a first emission surface 28A. The first incident surface 26A is the surface facing the first laser light-emitting element 22a and is the surface to which the excitation light E emitted from the first laser light-emitting element 22a is incident. The first reflection surface 27A is the surface that reflects the excitation light E incident from the first incident surface 26A and bends the optical path of the excitation light E. The first emission surface 28A is the surface facing the wavelength conversion element 24 and is the surface that emits the excitation light E reflected by the first reflection surface 27A toward the wavelength conversion element 24.

[0055] The second part 125B has a second incident surface 26B, a second reflection surface 27B, and a second emission surface 28B. The second incident surface 26B is the surface facing the second laser light-emitting element 22b and is the surface to which the excitation light E emitted from the second laser light-emitting element 22b is incident. The second reflection surface 27B is the surface that reflects the excitation light E incident from the second incident surface 26B and bends the optical path of the excitation light E. The second emission surface 28B is the surface facing the wavelength conversion element 24 and is the surface that emits the excitation light E reflected by the second reflection surface 27B toward the wavelength conversion element 24.

[0056] In this embodiment, the first portion 125A and the second portion 125B are molded integrally as described above. Therefore, the first incident surface 26A and the second incident surface 26B are each made up of a part of the incident surface 26, the first reflective surface 27A and the second reflective surface 27B are each made up of a part of the reflective surface 27, and the first injection surface 28A and the second injection surface 28B are each made up of a part of the injection surface 28.

[0057] In this embodiment, the angle of the reflective surface 27 with respect to the incident surface 26 is set such that it totally reflects the excitation light E incident from the incident surface 26. For example, assuming that the maximum emission angle of the excitation light E emitted from each laser light-emitting element 22 is approximately 70°, the first angle formed by the incident surface 26 and the emission surface 28 is set to, for example, 60°, and the second angle formed by the reflective surface 27 and the emission surface 28 is set to, for example, 40°. In other words, in the prism member 25, both the first and second angles are acute angles. Here, the first angle and the second angle are defined as the angles at which the incident surface 26 and the exit surface 28 intersect in a cross-section of the prism member 25 with respect to the central axis 25C, as shown in Figure 4, and the angles at which the incident surface 26 and the exit surface 28 intersect.

[0058] In this embodiment, the prism member 25 has an incident surface 26 including a first conical surface M1 and a reflective surface 27 including a second conical surface M2. As shown in Figure 3, the incident surface 26 and the reflective surface 27 are continuous in the circumferential direction of the central axis 25C.

[0059] The first optical layer 31 is provided on the incident surface 26. The first optical layer 31 is composed of, for example, a dichroic mirror, which transmits the excitation light E and reflects the fluorescence YL. The second optical layer 32 is provided on the ejection surface 28. The second optical layer 32 is composed of, for example, an AR coating film, and suppresses the reflection of light incident on the ejection surface 28.

[0060] The following describes the process by which the excitation light E emitted from each laser light-emitting element 22 is incident on the wavelength conversion element 24 via the prism member 25. Since the excitation light E emitted from each laser light-emitting element 22 behaves the same way, the following explanation will use the behavior of the excitation light E emitted from the first laser light-emitting element 22a as an example.

[0061] The first laser light-emitting element 22a emits excitation light E toward the first incident surface 26A of the prism member 25. The first laser light-emitting element 22a emits excitation light E along the surface 210 of the substrate 21. The first laser light-emitting element 22a emits excitation light E along the surface 240a of the wavelength conversion element 24 which is parallel to the surface 210 of the substrate 21.

[0062] The excitation light E passes through the first optical layer 31 provided on the first incident surface 26A and enters the interior of the prism member 25 from the first incident surface 26A. As the excitation light E enters from the first incident surface 26A, it is refracted, and its radiation angle is narrowed. Therefore, the prism member 25 can efficiently capture the excitation light E emitted from the first laser light-emitting element 22a at a large radiation angle.

[0063] The excitation light E that enters the interior of the prism member 25 from the first incident surface 26A enters the first reflection surface 27A. The optical path of the excitation light E reflected by the first reflection surface 27A is bent toward the first exit surface 28A and enters the first exit surface 28A. In addition, some of the excitation light E that enters the interior of the prism member 25 from the first incident surface 26A may be emitted directly from the first emission surface 28A without passing through the first reflection surface 27A and incident on the wavelength conversion element 24.

[0064] Furthermore, some of the excitation light E that enters the interior of the prism member 25 from the first incident surface 26A may enter a region of the first exit surface 28A that does not face the wavelength conversion element 24. If this region does not face the wavelength conversion element 24, it will absorb light, and a portion of the excitation light E will be lost. In contrast, in this embodiment, the utilization efficiency of the excitation light E can be increased by returning the excitation light E to the inside of the prism member 25 using a reflective member 30 provided in a region of the first emission surface 28A that does not face the wavelength conversion element 24.

[0065] In this embodiment, an air layer A is provided in the gap S between the wavelength conversion element 24 and the prism member 25. In other words, an air layer A is provided between the first emission surface 28A of the prism member 25 and the wavelength conversion element 24. Therefore, when the excitation light E is emitted from the first emission surface 28A, there is a risk that some components will be totally reflected and will not enter the wavelength conversion element 24.

[0066] In contrast, the prism member 25 of this embodiment suppresses the reflection of excitation light E at the interface between the first emission surface 28A and the air layer A by providing a second optical layer 32 on the first emission surface 28A. As a result, in the prism member 25, the first emission surface 28A can efficiently emit excitation light E toward the wavelength conversion element 24.

[0067] In this way, the prism member 25 reflects the excitation light E incident on the first incident surface 26A at the first reflection surface 27A toward the first emission surface 28A, and emits the excitation light E toward the wavelength conversion element 24 from the first emission surface 28A which intersects the first incident surface 26A and the first reflection surface 27A. In other words, the prism member 25 can cause the excitation light E to be incident on the wavelength conversion element 24 at a small incident angle by changing the optical path of the excitation light E emitted from the first laser light-emitting element 22a along the surface 240a of the wavelength conversion element 24.

[0068] The wavelength conversion element 24 emits fluorescent yellow light (YL), which is obtained by wavelength conversion of the excitation light E, and a portion of the excitation light E from the surface 240a of the wavelength conversion layer 240. The fluorescent yellow light (YL) and a portion of the excitation light E emitted from the wavelength conversion element 24 are incident on at least the first emission surface 28A of the prism member 25. Since the Lambert-emitting fluorescent yellow light (YL) has a larger radiation angle than the excitation light E, it is incident not only on the first emission surface 28A but on the entire emission surface 28.

[0069] In this embodiment, since an air layer A is provided between the wavelength conversion element 24 and the emission surface 28 of the prism member 25, the Lambert-emitting fluorescent YL is refracted at the interface between the air layer A and the emission surface 28, narrowing its radiation angle and allowing it to pass through the prism member 25. In addition, a portion of the excitation light E emitted from the surface 240a of the wavelength conversion layer 240 is also refracted at the interface between the air layer A and the emission surface 28, narrowing its radiation angle and allowing it to pass through the prism member 25.

[0070] In this embodiment, the second optical layer 32 provided on the ejection surface 28 suppresses the reflection of fluorescent YL and excitation light E at the interface between the ejection surface 28 and the air layer A. As a result, the prism member 25 can efficiently capture a portion of the fluorescent YL and excitation light E emitted from the wavelength conversion element 24 through the ejection surface 28.

[0071] In this way, a portion of the fluorescent YL and excitation light E taken into the prism member 25 is incident on the reflective surface 27. A portion of the fluorescent YL and excitation light E passes through the reflective surface 27 and is emitted from the prism member 25 as white illumination light WL.

[0072] Of the fluorescent YL captured within the prism member 25, the components emitted at a large radiation angle are incident on the incident surface 26. At this time, the fluorescent YL is reflected by the first optical layer 31 provided on the incident surface 26, returned to the prism member 25, and emitted from the prism member 25 after passing through the reflective surface 27.

[0073] Thus, according to the prism member 25 of this embodiment, the fluorescent YL emitted from the wavelength conversion element 24 can be extracted from the reflective surface 27. In other words, when viewed from above, the prism member 25 can emit fluorescent YL from the region where the reflective surface 27 is provided.

[0074] The light source device 20 of this embodiment can emit fluorescent yellow light (YL) with its radiation angle limited by the prism member 25. Therefore, the fluorescent yellow light emitted from the light source device 20 is well captured by the pickup optical system 34.

[0075] The light source device 20 according to this embodiment described above provides the following effects. The light source device 20 of this embodiment comprises a substrate 21 having a first laser light-emitting element 22a that emits excitation light E, a wavelength conversion element 24 that converts the excitation light E into a yellow wavelength fluorescent element YL, a first support part 21a that supports the first laser light-emitting element 22a, and a second support part 21b that supports the wavelength conversion element 24, and a prism member 25 that is arranged in the optical path of the excitation light E between the first laser light-emitting element 22a and the wavelength conversion element 24 and guides the excitation light E emitted from the first laser light-emitting element 22a to the wavelength conversion element 24. The prism member 25 has a first incident surface 26A facing the first laser light-emitting element 22a and into which the excitation light E emitted from the first laser light-emitting element 22a is incident, a first reflective surface 27A that reflects the excitation light E incident from the first incident surface 26A and bends the optical path of the excitation light E, and a first emission surface 28A facing the wavelength conversion element 24 and that emits the excitation light E reflected by the first reflective surface 27A toward the wavelength conversion element 24. The first incident surface 26A, the first reflective surface 27A, and the first emission surface 28A intersect with each other.

[0076] According to the light source device 20 of this embodiment, by changing the optical path of the excitation light E emitted from the first laser light-emitting element 22a with the prism member 25, the excitation light E can be incident on the wavelength conversion element 24 at a small incident angle.

[0077] The inventors conducted a simulation to verify the effect of the prism member 25. In this simulation, the incident angle of the excitation light E on the surface 240a of the wavelength conversion element 24 (wavelength conversion layer 240) was verified for the light source device 20 of this embodiment with the prism member 25 and for the light source device without the prism member 25.

[0078] From the simulation results, it was confirmed that in the case of the light source device 20 of this embodiment, the incident angle of the excitation light E on the surface 240a of the wavelength conversion element 24 is in the range of 0° to 50°. An incident angle of 0° means that the excitation light E is incident on the surface 240a from a direction perpendicular to it.

[0079] Furthermore, in the case of the comparative example light source device without the prism member 25, it was confirmed that the incident angle of the excitation light E on the surface 240a of the wavelength conversion element 24 was in the range of 50° to 80°. In addition, it was confirmed that when the prism member 25 is absent, the excitation light E is incident on the surface 240a of the wavelength conversion element 24 from an oblique direction, and the incident angle of the excitation light E on the wavelength conversion element 24 becomes larger.

[0080] As the incident angle of excitation light E on the wavelength conversion element 24 increases, the excitation light E is reflected by the surface 240a of the wavelength conversion element 24, making it difficult for it to enter the wavelength conversion element 24, thus reducing the fluorescence conversion efficiency of the wavelength conversion element 24. Furthermore, when the incident angle is large, it is difficult to design an anti-reflective coating such as an AR coating, making it difficult to improve the fluorescence conversion efficiency using an anti-reflective coating. Therefore, in the comparative example light source device, the component of excitation light E reflected from the surface 240a of the wavelength conversion element 24 increases, reducing the fluorescence conversion efficiency and making it impossible to generate bright fluorescence YL.

[0081] In contrast, with the light source device 20 of this embodiment, the incident angle of the excitation light E to the wavelength conversion element 24 can be reduced by the prism member 25, so that the excitation light E can be efficiently incident on the wavelength conversion element 24. Simulations have shown that the light source device 20 of this embodiment can increase the amount of excitation light E incident on the wavelength conversion element 24 by approximately 3.5 times compared to the light source device of the comparative example that does not use the prism member 25. Therefore, according to the light source device 20 of this embodiment, by changing the optical path of the excitation light E emitted from the first laser light-emitting element 22a with the prism member 25, the excitation light E can be efficiently incident on the wavelength conversion element 24, thereby generating bright fluorescence YL as illumination light WL.

[0082] In the light source device 20 of this embodiment, the angle between the first incident surface 26A and the first emission surface 28A is acute.

[0083] With a prism member 25 having such an angular relationship, the optical path of the excitation light E can be changed as described above and efficiently incident onto the wavelength conversion element 24.

[0084] In the light source device 20 of this embodiment, the wavelength conversion element 24 has a wavelength conversion layer 240 that converts the excitation light E to fluorescence YL, and a reflection layer 241 provided on the side opposite to the prism member 25 relative to the wavelength conversion layer 240, and emits fluorescence YL toward the prism member 25.

[0085] With this configuration, the fluorescent YL emitted from the reflective wavelength conversion element 24 can be incident on the prism member 25.

[0086] In the light source device 20 of this embodiment, the prism member 25 further has a first optical layer 31 provided on the first incident surface 26A that transmits excitation light E and reflects fluorescence YL.

[0087] With this configuration, the fluorescent YL emitted from the wavelength conversion element 24 and incident on the first incident surface 26A can be returned to the prism member 25. As a result, the prism member 25 emits the fluorescent YL from the region where the reflective surface 27 is provided, allowing the emission angle of the fluorescent YL to be limited.

[0088] In the light source device 20 of this embodiment, an air layer A is provided between the first emission surface 28A and the wavelength conversion element 24. In this embodiment, the prism member 25 further has a second optical layer 32 provided on the first emission surface 28A that suppresses the reflection of incident light.

[0089] With this configuration, the fluorescent YL emitted by Lambert at the interface between the air layer A and the emission surface 28 is refracted, allowing the fluorescent YL to be captured by the prism member 25 with a narrowed emission angle. Furthermore, the inclusion of the second optical layer 32 suppresses the reflection of the excitation light E at the interface between the first emission surface 28A and the air layer A, allowing the first emission surface 28A to efficiently emit the excitation light E towards the wavelength conversion element 24.

[0090] In the light source device 20 of this embodiment, the base material 21 further has a third support portion 21c that supports the prism member 25, the prism member 25 is fixed to the third support portion 21c via a reflective member 30, and the reflective member 30 is provided in a region of the first emission surface 28A that does not face the wavelength conversion element 24.

[0091] With this configuration, the reflective member 30 returns the excitation light E to the inside of the prism member 25, thereby increasing the utilization efficiency of the excitation light E.

[0092] In the light source device 20 of this embodiment, the second support portion 21b is a recess 213 formed in a position that overlaps with a part of the third support portion 21c on the base material 21 in a plan view.

[0093] With this configuration, the prism member 25, each laser light-emitting element 22, and the wavelength conversion element 24 can be supported in a predetermined positional relationship on the substrate 21.

[0094] In the light source device 20 of this embodiment, the first laser light-emitting element 22a emits excitation light E along the surface 240a into which the excitation light E is incident at the wavelength conversion element 24.

[0095] When the excitation light E is emitted along the surface 240a, the fluorescence conversion efficiency is most likely to decrease. Therefore, according to this embodiment, the effect of changing the optical path of the excitation light E by using the prism member 25 can be made more pronounced.

[0096] In the light source device 20 of this embodiment, the prism member 25 is a single member formed by integrally molding a first portion 125A corresponding to the first laser light-emitting element 22a and a second portion 125B corresponding to the second laser light-emitting element 22b.

[0097] This configuration facilitates alignment between the prism member 25 and each laser light-emitting element 22.

[0098] In the light source device 20 of this embodiment, the prism member 25 includes an incident surface 26 that includes a first conical surface M1 having its apex on the side opposite to the wavelength conversion element 24 relative to the prism member 25, a reflective surface 27 that includes a second conical surface M2 located inside the first conical surface M1 and having its apex on the substrate 21 side, and an exit surface 28 facing the wavelength conversion element 24. The first incident surface 26A and the second incident surface 26B are part of the incident surface 26, the first reflective surface 27A and the second reflective surface 27B are part of the reflective surface 27, and the first exit surface 28A and the second exit surface 28B are part of the exit surface 28.

[0099] With this configuration, since a prism member 25 is used in which the incident surface 26 and the reflective surface 27 are continuous in the circumferential direction of the central axis 25C, it is not necessary to evenly arrange each laser light-emitting element 22 in the circumferential direction of the central axis 25C of the prism member 25. Therefore, alignment between the prism member 25 and the laser light-emitting elements 22 becomes easier.

[0100] The projector 1 according to this embodiment described above provides the following effects. The projector 1 of this embodiment comprises a light source device 20, light modulators 4B, 4G, and 4R that form image light by modulating blue light LB, green light LG, and red light LR from the light source device 20, and a projection optical device 6 that projects the aforementioned image light.

[0101] According to the projector 1 of this embodiment, since it is equipped with a light source device 20 that generates bright fluorescent yellow light (YL), it is possible to form and project a high-brightness image.

[0102] Although one embodiment of the present invention has been described as an example, the present invention is not necessarily limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0103] For example, in the light source device 20 of the above embodiment, the case in which the incident surface 26 and the exit surface 28 of the prism member 25 are composed of a part of a conical surface was given as an example. In other words, the case in which the incident surface 26 and the exit surface 28 are composed of curved surfaces was given as an example, but the shape of the prism member 25 is not limited to this.

[0104] (First variation) Figure 5 is a plan view of the prism member 250 according to the first modified example. As shown in Figure 5, the prism member 250 may be constructed by integrally molding a plurality of square pyramidal parts 251 provided opposite each laser light-emitting element 22. The prism member 250 in this modified example has a planar shape consisting of polygons. With the prism member 250 in this modified example, since the incident surface 260 is composed of a plurality of planes, the formation of the first optical layer 31 on the incident surface 260 becomes easier. Furthermore, the planar shape of the prism member 250 may be adjusted to correspond to the number of laser light-emitting elements 22. For example, if there are six laser light-emitting elements 22, the planar shape of the prism member 250 will be hexagonal.

[0105] Furthermore, in the above embodiment of the light source device 20, an example was given in which an air layer A is provided in the gap S between the wavelength conversion element 24 and the prism member 25, but the emission surface 28 of the prism member 25 and the wavelength conversion element 24 may be in contact.

[0106] (Second variation) Figure 6 is a plan view of the prism member 350 according to the second modified example. As shown in Figure 6, the prism member 25 and the wavelength conversion element 24 are in contact in the prism member 350. With this configuration, total internal reflection does not occur at the interface with the air layer when the excitation light E is emitted from the emission surface 28 of the prism member 25, so more excitation light E can be incident on the wavelength conversion element 24.

[0107] Furthermore, although the above embodiment uses a single prism member 25 formed by integrally molding multiple parts 125 corresponding to each laser light-emitting element 22, the multiple parts 125, including the first part 125A and the second part 125B, may each be composed of separate parts.

[0108] Furthermore, although the above embodiment and modified light source devices were given as examples of having multiple laser light-emitting elements 22, the number of laser light-emitting elements 22 is not limited, and may consist only of the first laser light-emitting element 22a.

[0109] Furthermore, although the above embodiment illustrates a projector 1 equipped with three optical modulators 4R, 4G, and 4B, it is also possible to apply this to a projector that displays color images with a single optical modulator. Moreover, the optical modulator is not limited to the liquid crystal panel described above; for example, a digital mirror device can also be used.

[0110] Furthermore, while the above embodiment shows an example of applying the light source device according to the present invention to a projector, it is not limited to this. The light source device according to the present invention can also be applied to lighting fixtures such as automobile headlights.

[0111] A light source device according to an embodiment of the present invention may have the following configuration. A light source device according to one aspect of the present invention comprises a substrate having: a first laser light-emitting element that emits first light in a first wavelength band; a wavelength conversion element that converts the first light into second light in a second wavelength band different from the first wavelength band; a first support part that supports the first laser light-emitting element; and a second support part that supports the wavelength conversion element; and a first optical element disposed on the optical path of the first light between the first laser light-emitting element and the wavelength conversion element, which guides the first light emitted from the first laser light-emitting element to the wavelength conversion element, wherein the first optical element has: a first incident surface facing the first laser light-emitting element and into which the first light emitted from the first laser light-emitting element is incident; a first reflective surface that reflects the first light incident from the first incident surface and bends the optical path of the first light; and a first output surface facing the wavelength conversion element and emitting the first light reflected by the first reflective surface toward the wavelength conversion element, wherein the first incident surface, the first reflective surface, and the first output surface intersect each other.

[0112] In one embodiment of the present invention, the angle between the first incident surface and the first emission surface may be an acute angle.

[0113] In a light source device according to one aspect of the present invention, the wavelength conversion element may have a wavelength conversion layer that converts first light into second light, and a reflective layer provided on the side opposite to the first optical element with respect to the wavelength conversion layer, and emit the second light toward the first optical element.

[0114] In a light source device according to one aspect of the present invention, the first optical element may further have a first optical layer provided on the first incident surface that transmits first light and reflects second light.

[0115] In one embodiment of the present invention, the first emission surface and the wavelength conversion element may be in contact with each other.

[0116] In one embodiment of the present invention, a light source device may be configured such that an air layer is provided between the first emission surface and the wavelength conversion element.

[0117] In a light source device according to one aspect of the present invention, the first optical element may further have a second optical layer provided on the first emission surface that suppresses the reflection of incident light.

[0118] In one embodiment of the present invention, a light source device further comprises a reflective member that reflects first light and second light, the substrate further has a third support portion that supports a first optical element, the first optical element is fixed to the third support portion via the reflective member, and the reflective member is provided in a region of the first emission surface that does not face the wavelength conversion element.

[0119] In a light source device according to one aspect of the present invention, the second support portion may be a recess in which a wavelength conversion element is housed, and the recess may be formed in a position that overlaps with a part of the third support portion on the substrate in a plan view.

[0120] In one embodiment of the present invention, the light source device may be configured such that the wavelength conversion element has an incident light surface to which the first light is incident, and the first laser light-emitting element emits the first light along the incident light surface of the wavelength conversion element.

[0121] In one embodiment of the present invention, the light source device further comprises a second laser light-emitting element that emits first light, and a second optical element arranged on the optical path of the first light between the second laser light-emitting element and a wavelength conversion element, which guides the first light emitted from the second laser light-emitting element to the wavelength conversion element, wherein the first optical element and the second optical element are composed of a single prism member.

[0122] In a light source device according to one aspect of the present invention, the second optical element has a second incident surface, a second reflective surface, and a second exit surface that intersect each other, and the prism member has a first surface including a first conical surface having its apex on the side opposite to the wavelength conversion element with respect to the prism member, a second surface including a second conical surface located inside the first conical surface and having its apex on the substrate side, and a third surface facing the wavelength conversion element, wherein the first incident surface and the second incident surface are part of the first surface, the first reflective surface and the second reflective surface are part of the second surface, and the first exit surface and the second exit surface are part of the third surface.

[0123] A projector according to one aspect of the present invention may have the following configuration. A projector according to one aspect of the present invention comprises a light source device according to the above aspect of the present invention, an optical modulator for modulating light from the light source device, and a projection optical device for projecting light modulated by the optical modulator. [Explanation of symbols]

[0124] 1…Projector, 4B,4G,4R…Optical Modulator, 6…Projection Optical Device, 20…Light Source Device, 21…Substrate, 21a…First Support, 21b…Second Support, 21c…Third Support, 22…Laser Light-Emitting Device, 22a…First Laser Light-Emitting Device, 22b…Second Laser Light-Emitting Device, 24…Wavelength Conversion Element, 25,250,350…Prism Member, 26,260…Incident Surface, 26A…First Incident Surface, 26B…Second Incident Surface, 27…Reflecting Surface, 27A… 1st reflective surface, 27B...2nd reflective surface, 28...Ejection surface, 28A...1st ejection surface, 28B...2nd ejection surface, 30...Reflective member, 31...1st optical layer, 32...2nd optical layer, 125A...1st part (1st optical element), 125B...2nd part (2nd optical element), 213...Recess, 240...Wavelength conversion layer, 240a...Surface (light incident surface), 241...Reflective layer, A...Air layer, E...Excitation light (1st light), M1...1st conical surface, M2...2nd conical surface, YL...Fluorescence (2nd light).

Claims

1. A first laser light-emitting element that emits first light in the first wavelength band, A wavelength conversion element that converts the first light into a second light in a second wavelength band different from the first wavelength band, A substrate having a first support portion for supporting the first laser light-emitting element and a second support portion for supporting the wavelength conversion element, The system comprises a first optical element positioned on the optical path of the first light between the first laser light-emitting element and the wavelength conversion element, which guides the first light emitted from the first laser light-emitting element to the wavelength conversion element, The first optical element is, A first incident surface facing the first laser light-emitting element and into which the first light emitted from the first laser light-emitting element is incident, A first reflecting surface that reflects the first light incident from the first incident surface and bends the optical path of the first light, It has a first emission surface that faces the wavelength conversion element and emits the first light reflected by the first reflective surface toward the wavelength conversion element, The first incident surface, the first reflective surface, and the first ejection surface intersect each other, An air layer is provided between the first emission surface and the wavelength conversion element. The first optical element further comprises a second optical layer provided on the first emission surface for suppressing the reflection of incident light. A light source device characterized by the following features.

2. A first laser light-emitting element that emits first light in the first wavelength band, A wavelength conversion element that converts the first light into a second light in a second wavelength band different from the first wavelength band, A substrate having a first support portion for supporting the first laser light-emitting element and a second support portion for supporting the wavelength conversion element, The system comprises a first optical element positioned on the optical path of the first light between the first laser light-emitting element and the wavelength conversion element, which guides the first light emitted from the first laser light-emitting element to the wavelength conversion element, The first optical element is, A first incident surface facing the first laser light-emitting element and into which the first light emitted from the first laser light-emitting element is incident, A first reflecting surface that reflects the first light incident from the first incident surface and bends the optical path of the first light, It has a first emission surface that faces the wavelength conversion element and emits the first light reflected by the first reflective surface toward the wavelength conversion element, The first incident surface, the first reflective surface, and the first ejection surface intersect each other, The device further comprises a reflective member that reflects the first light and the second light, The substrate further has a third support portion that supports the first optical element, The first optical element is fixed to the third support portion via the reflective member, The reflective member is provided in a region of the first emission surface that does not face the wavelength conversion element. A light source device characterized by the following features.

3. A first laser light-emitting element that emits first light in the first wavelength band, A wavelength conversion element that converts the first light into a second light in a second wavelength band different from the first wavelength band, A substrate having a first support portion for supporting the first laser light-emitting element and a second support portion for supporting the wavelength conversion element, A first optical element is positioned on the optical path of the first light between the first laser light-emitting element and the wavelength conversion element, and guides the first light emitted from the first laser light-emitting element to the wavelength conversion element. The second laser light-emitting element that emits the first light, The system comprises a second optical element positioned on the optical path of the first light between the second laser light-emitting element and the wavelength conversion element, which guides the first light emitted from the second laser light-emitting element to the wavelength conversion element, The first optical element is, A first incident surface facing the first laser light-emitting element and into which the first light emitted from the first laser light-emitting element is incident, A first reflecting surface that reflects the first light incident from the first incident surface and bends the optical path of the first light, It has a first emission surface that faces the wavelength conversion element and emits the first light reflected by the first reflective surface toward the wavelength conversion element, The first incident surface, the first reflective surface, and the first ejection surface intersect each other, The first optical element and the second optical element are composed of a single prism member. The second optical element has a second incident surface, a second reflective surface, and a second exit surface that intersect each other. The prism member is The prism member has a first surface including a first conical surface having its vertex on the side opposite to the wavelength conversion element, A second surface including a second conical surface located inside the first conical surface and having its apex on the substrate side, It has a third surface facing the wavelength conversion element, The first incident surface and the second incident surface are composed of a part of the first surface. The first reflective surface and the second reflective surface are composed of a part of the second surface. The first injection surface and the second injection surface are formed from a part of the third surface. A light source device characterized by the following features.

4. The second support portion is a recess in which the wavelength conversion element is housed, The recess is formed in a position that overlaps with a part of the third support portion on the substrate in a plan view. The light source device according to claim 2.

5. The second laser light-emitting element that emits the first light, The system further comprises a second optical element positioned on the optical path of the first light between the second laser light-emitting element and the wavelength conversion element, which guides the first light emitted from the second laser light-emitting element to the wavelength conversion element, The first optical element and the second optical element are composed of a single prism member. A light source device according to any one of claims 1, 2, or 4.

6. The second optical element has a second incident surface, a second reflective surface, and a second exit surface that intersect each other. The prism member is The prism member has a first surface including a first conical surface having its vertex on the side opposite to the wavelength conversion element, A second surface including a second conical surface located inside the first conical surface and having its apex on the substrate side, It has a third surface facing the wavelength conversion element, The first incident surface and the second incident surface are composed of a part of the first surface. The first reflective surface and the second reflective surface are composed of a part of the second surface. The first injection surface and the second injection surface are formed from a part of the third surface. The light source device according to claim 5.

7. The first emission surface and the wavelength conversion element are in contact. A light source device according to any one of claims 2 to 4.

8. An air layer is provided between the first emission surface and the wavelength conversion element. A light source device according to any one of claims 2 to 4.

9. The first optical element further comprises a second optical layer provided on the first emission surface for suppressing the reflection of incident light. The light source device according to feature 8.

10. The device further comprises a reflective member that reflects the first light and the second light, The substrate further has a third support portion that supports the first optical element, The first optical element is fixed to the third support portion via the reflective member, The reflective member is provided in a region of the first emission surface that does not face the wavelength conversion element. A light source device according to claim 1 or 3.

11. The second support portion is a recess in which the wavelength conversion element is housed, The recess is formed in a position that overlaps with a part of the third support portion on the substrate in a plan view. The light source device according to feature 10.

12. The angle between the first incident surface and the first exit surface is acute. A light source device according to any one of claims 1 to 11, characterized by the features described above.

13. The wavelength conversion element comprises a wavelength conversion layer that converts the first light into the second light, and a reflective layer provided on the side opposite to the first optical element relative to the wavelength conversion layer, and emits the second light toward the first optical element. A light source device according to any one of claims 1 to 12, characterized by the features described herein.

14. The first optical element further comprises a first optical layer provided on the first incident surface that transmits first light and reflects second light. A light source device according to any one of claims 1 to 13.

15. The wavelength conversion element has an incident light surface to which the first light is incident, The first laser light-emitting element emits the first light along the light incident surface of the wavelength conversion element. A light source device according to any one of claims 1 to 14.

16. A light source device according to any one of claims 1 to 15, A light modulator that modulates the light from the aforementioned light source device, The system comprises a projection optical device that projects light modulated by the aforementioned optical modulation device, A projector characterized by the following features.

Images