Wavelength conversion device, light source device, and projection-type video display device

Abstract

This wavelength conversion device has a substrate, an adhesive layer provided on the substrate, and a wavelength conversion layer provided on the adhesive layer and configured to contain wavelength conversion particles. The wavelength conversion particles have a first length along a first direction and a second length that is shorter than the first length along a second direction, which is orthogonal to the first direction. The wavelength conversion particles are disposed in the wavelength conversion layer such that the first direction is orthogonal to the surface of the substrate.

Description

Wavelength conversion device, light source device, and projection-type image display device

[0001] The present disclosure relates to a wavelength conversion device, a light source device, and a projection-type image display device.

[0002] Conventionally, wavelength conversion devices arranged in an optical path have been used as components of projection-type image display devices such as projectors. To improve the performance of wavelength conversion devices, there has been a demand for improvements in the wavelength conversion efficiency of wavelength conversion particles contained in the wavelength conversion device, i.e., improved light emission efficiency, improved heat dissipation efficiency of heat generated during light emission, and improved utilization efficiency in optical systems downstream of the wavelength conversion device. For example, Patent Document 1 discloses a configuration for improving heat dissipation efficiency in a phosphor wheel serving as a wavelength conversion device by adhering a highly thermally conductive adhesive layer to wavelength conversion particles that generate heat during light emission.

[0003] Japanese Patent Application Laid-Open No. 2021-92728

[0004] The present disclosure has been devised in view of the above-mentioned conventional circumstances, and aims to improve the efficiency performance of wavelength conversion devices.

[0005] The present disclosure provides a wavelength converting device comprising a substrate, an adhesive layer provided on the substrate, and a wavelength converting layer provided on the adhesive layer and comprising wavelength converting particles, the wavelength converting particles having a first length along a first direction and a second length along a second direction perpendicular to the first direction, the second length being shorter than the first length, and the wavelength converting particles being arranged in the wavelength converting layer such that the first direction is perpendicular to the plane of the substrate.

[0006] The present disclosure also provides a light source device having a wavelength conversion device comprising: a substrate; an adhesive layer provided on the substrate; and a wavelength conversion layer provided on the adhesive layer and containing wavelength conversion particles, the wavelength conversion particles having a first length along a first direction and a second length along a second direction perpendicular to the first direction, the second length being shorter than the first length, and the wavelength conversion particles being arranged in the wavelength conversion layer such that the first direction is perpendicular to the surface of the substrate.

[0007] The present disclosure also provides a projection-type video display device having a light source device with a wavelength conversion device, the light source device having a wavelength conversion device comprising: a substrate; an adhesive layer provided on the substrate; and a wavelength conversion layer provided on the adhesive layer and containing wavelength conversion particles, the wavelength conversion particles having a first length along a first direction and a second length along a second direction perpendicular to the first direction, the second length being shorter than the first length, and the wavelength conversion particles being arranged in the wavelength conversion layer such that the first direction is perpendicular to the surface of the substrate.

[0008] Any combination of the above components and conversion of the expression of the present disclosure between methods, devices, systems, etc. are also valid aspects of the present disclosure.

[0009] According to the present disclosure, it is possible to improve the efficiency performance of wavelength conversion devices.

[0010] Schematic diagram showing an example of the configuration around a wavelength conversion particle according to embodiment 1. Schematic diagram showing an example of the configuration around a wavelength conversion particle according to variation 1 of embodiment 1. Schematic diagram showing an example of the configuration around a wavelength conversion particle according to variation 2 of embodiment 1. Schematic diagram showing an example of the configuration around a wavelength conversion particle according to variation 3 of embodiment 1. Schematic diagram showing an example of the configuration around a wavelength conversion particle according to variation 4 of embodiment 1. Schematic diagram showing an example of the configuration around a phosphor wheel according to embodiment 1. Schematic diagram showing an example of the configuration of a phosphor wheel according to variation 1 of embodiment 1. Schematic diagram showing an example of the configuration of a phosphor wheel according to variation 2 of embodiment 1. Schematic diagram showing an example of the configuration of a phosphor wheel according to variation 3 of embodiment 1. Schematic diagram showing an example of the configuration of a phosphor wheel according to variation 4 of embodiment 1. Schematic diagram showing an example of the configuration of a phosphor wheel according to variation 5 of embodiment 1. Schematic diagram showing a configuration example of a light source device according to Variation 1 of Embodiment 1 Schematic diagram showing a configuration example of a light source device according to Variation 2 of Embodiment 1 Schematic diagram showing a configuration example of a light source device according to Variation 3 of Embodiment 1 Schematic diagram showing a configuration example of a light source device according to Variation 4 of Embodiment 1 Schematic diagram showing a configuration example of a light source device according to Variation 5 of Embodiment 1 Schematic diagram showing a configuration example of a light source device according to Variation 6 of Embodiment 1 Schematic diagram showing a configuration example of a light source device according to Variation 7 of Embodiment 1 Schematic diagram showing a configuration example of a light source device according to Variation 8 of Embodiment 1 Schematic diagram showing a configuration example of a projection-type video display device according to Embodiment 1 Schematic diagram showing a configuration example of a projection-type video display device according to Variation 1 of Embodiment 1 Schematic diagram showing a configuration example of a projection-type video display device according to Variation 2 of Embodiment 1 Schematic diagram for explaining the light-emitting region of wavelength conversion particles according to embodiment 1

[0011] (Background to the present disclosure) Conventionally, various configurations have been considered for wavelength conversion devices used in projection-type image display devices such as projectors, taking into consideration factors such as the heat dissipation efficiency of heat generated when wavelength conversion particles emit light, the light emission efficiency of wavelength conversion particles, and the utilization efficiency in downstream optical systems. Hereinafter, for convenience, such efficiency-related performance will be collectively referred to as "efficiency performance." Because heat generated by wavelength conversion particles affects surrounding components, more efficient heat dissipation and heat generation suppression are required. Generally, heat generated by wavelength conversion particles is dissipated by contacting them with a heat dissipation member with higher thermal conductivity. Furthermore, in order to suppress heat generation and improve utilization efficiency in downstream optical systems, it is required to increase efficiency by limiting the emission of light from the multiple wavelength conversion particles constituting a wavelength conversion device to an appropriate position or range.

[0012] Hereinafter, with reference to the accompanying drawings as appropriate, detailed descriptions of embodiments specifically disclosing a wavelength conversion device, a light source device, and a projection-type image display device according to the present disclosure will be provided. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters or redundant descriptions of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0013] In the drawings, equivalent components are designated by the same reference numerals. When describing the various aspects of the present specification, if the components included in each aspect need to be individually described, a suffix (a, b, ...) is added to the reference numeral. On the other hand, when the components are commonly described, the suffix is ​​omitted from the reference numeral.

[0014] Furthermore, in this specification, terms such as "first" and "second" are used merely to distinguish between components for the convenience of description, and are not intended to limit interpretation to specific components. Therefore, it will be understood that these expressions should be interpreted appropriately depending on the configuration to which the invention according to the present disclosure is applied.

[0015] Each figure shows a three-dimensional coordinate system consisting of an X-axis, a Y-axis, and a Z-axis, and the directions of each axis are described as corresponding to each other. Here, the X-Y plane in the figure is described as the horizontal direction, and the Z-axis direction is described as the height direction. Note that the settings of the directions of each axis are merely examples, and are not intended to be interpreted in a restrictive manner. Furthermore, the dimensions and arrangement of each layer in each figure described below are shown in a simplified manner for the purpose of explanation, and are not intended to be interpreted in a restrictive manner unless otherwise specified.

[0016] <First Embodiment> A wavelength conversion device according to one embodiment of the present disclosure is, for example, a phosphor wheel used in a projection-type image display device such as a projector. Known methods may be used to control the wavelength conversion device and the light source device in the projection-type image display device, and detailed description thereof will be omitted here.

[0017] In the following description, various exemplary embodiments of the wavelength conversion particles contained in a phosphor wheel will be described using FIGS. 1A to 1E. Various exemplary embodiments of the phosphor wheel will be described using FIGS. 2A to 2F. Various exemplary embodiments of a light source device including a phosphor wheel will be described using FIGS. 3A to 3H. Finally, exemplary embodiments of a projection-type image display device including a light source device will be described using FIGS. 4A to 4C. Any combination of a phosphor wheel, a light source device, and a projection-type image display device may be used, unless otherwise specified below. Therefore, the configurations and combinations described below are merely examples and are not intended to be limiting.

[0018] [Configuration example around wavelength conversion particles] Fig. 1A is a diagram showing a configuration example around wavelength conversion particles 4 that constitute a phosphor wheel according to this embodiment. The configuration example shown in Fig. 1A is a reflective configuration in which excitation light is incident from the upper side of the drawing, and the fluorescence as reflected light is emitted toward the outside of the upper side of the drawing. In order from the excitation light incident side, a wavelength conversion layer 3, an adhesive layer 2, and a substrate 1 form a layer structure.

[0019] The wavelength conversion layer 3 is formed by a binder 5 containing wavelength conversion particles 4. The binder 5 is made of a material such as silicone or silsesquioxane. The wavelength conversion particles 4 are excited by excitation light, e.g., laser light, from a light source (not shown) to emit fluorescence. In this embodiment, the wavelength conversion layer 4 is described using a fluorescent material that emits fluorescence as an example, but this is not limited to this. Other types of materials that perform wavelength conversion may also be used as wavelength conversion particles. The wavelength conversion particles 4 have an ellipsoidal shape with a minor axis and a major axis. The ellipsoidal shape here may include shapes such as a cylindrical, needle-like, or polygonal prism-like shape. The wavelength conversion particles 4 are arranged so that their major axis lies along the propagation direction of the excitation light (the Z-axis direction in the example of FIG. 1A ) and a direction perpendicular to the propagation direction (the X-axis or Y-axis direction in the example of FIG. 1A ) and their minor axis lies perpendicular to the propagation direction.

[0020] The adhesive layer 2 contains a reflective filler material to increase the reflectance of light from the wavelength conversion layer 3, and reflects external excitation light and fluorescence emitted from the wavelength conversion particles 4. In other words, the adhesive layer 2 functions as a reflective layer. Therefore, the adhesive layer 2 is made of a material that has a high reflectance for each type of light. The adhesive layer 2 is made of, for example, titanium oxide (TiO ２ Furthermore, adhesive layer 2 has the role of conducting heat generated when wavelength converting particles 4 emit light to substrate 1 side.

[0021] The substrate 1 is made of a material such as aluminum (Al) or copper (Cu). The substrate 1 may be made of a material other than a metal as long as it has a higher thermal conductivity than the wavelength conversion layer 3 and the adhesive layer 2.

[0022] 1A , excitation light incident from outside is absorbed by the wavelength-converting particles 4 and wavelength-converted to fluorescence. Excitation light that is not absorbed by the wavelength-converting particles 4 reaches the adhesive layer 2, where it is reflected by the adhesive layer 2, which functions as a reflective layer, and changes its traveling direction. The reflected excitation light is again incident on the wavelength-converting particles 4, where it is absorbed by them, and some or all of it is wavelength-converted to fluorescence. Again, excitation light that is not wavelength-converted is emitted to the outside at the upper side of the drawing.

[0023] The wavelength-converted fluorescence is completely diffused and emitted in all directions. Fluorescence emitted in the direction of the incident excitation light is emitted directly to the outside. Fluorescence emitted in the direction of the adhesive layer 2 reaches the adhesive layer 2 and is reflected by the adhesive layer 2, which acts as a reflective layer, changing its direction of travel. The reflected fluorescence is emitted to the outside in the direction of the incident excitation light.

[0024] (Variation 1) Fig. 1B is a diagram showing Variation 1 around wavelength conversion particles 4 included in a phosphor wheel according to the present embodiment. The difference in configuration from Fig. 1A is that the embodiment of Fig. 1B has a two-layer structure in which the reflective layer 6 and adhesive layer 7 are separately configured. That is, in the example of Fig. 1B, the layer structure is made up of wavelength conversion layer 3, reflective layer 6, adhesive layer 7, and substrate 1, in that order from the excitation light incident side.

[0025] The reflective layer 6 contains, for example, a reflective filler material to increase the reflectance of light from the wavelength conversion layer 3, and reflects external excitation light and fluorescence emitted from the wavelength conversion particles 4. The reflective layer 6 is made of a material with high reflectance for each type of light. The adhesive layer 7 is made of, for example, titanium oxide (TiO ２ The adhesive layer 7 is configured by encapsulating a material such as a silicone or silsesquioxane in a binder made of a material such as silicone or silsesquioxane, and by encapsulating highly thermally conductive particles (not shown) in the binder to improve heat dissipation efficiency.

[0026] In the configuration example of Fig. 1B, the optical behavior is the same as in the configuration example of Fig. 1A. On the other hand, in the configuration example of Fig. 1B, the reflective layer 6 and the adhesive layer 7 are configured separately. In this configuration, the adhesive layer 7 does not include components necessary for the reflective function, and can be configured only from a material with a higher thermal conductivity, making it possible to efficiently dissipate heat generated during wavelength conversion by the wavelength converting particles 4 toward the substrate 1. Therefore, in the configuration example of Fig. 1B, it is possible to further improve heat dissipation efficiency.

[0027] (Variation 2) Fig. 1C is a diagram showing Variation 2 around wavelength conversion particles 4 included in a phosphor wheel according to the present embodiment. The difference in configuration from Fig. 1B is that the arrangement of the reflective layer 6 and adhesive layer 7 is reversed in the embodiment shown in Fig. 1C. That is, in the example shown in Fig. 1C, the wavelength conversion layer 3, adhesive layer 7, reflective layer 6, and substrate 1 form a layer structure in this order from the excitation light incident side.

[0028] The reflective layer 6 has the same configuration as that of the first modification shown in FIG. 1B and reflects external excitation light and fluorescence emitted from the wavelength converting particles 4. The reflective layer 6 may be a highly reflective layer formed by laminating a dielectric multilayer film or a metal film on the surface of the substrate 1. The adhesive layer 7 may be made of, for example, titanium oxide (TiO ２ The adhesive layer 7 is made of a material that has high transmittance to light in the wavelength range of the excitation light or fluorescence, such as silicone or silsesquioxane.

[0029] In the configuration example of FIG. 1C, the optical behavior is similar to the configuration example of FIG. 1B.

[0030] (Variation 3) Figures 1A to 1C show examples of a reflective type configuration. Figure 1D explains an example of a transmissive type configuration. In the example configuration shown in Figure 1D, excitation light is incident from the upper side of the drawing, and fluorescence is emitted outward from the lower side of the drawing. In order from the excitation light incident side, a layer structure is formed of a wavelength conversion layer 3, an adhesive layer 7, a reflective layer 6, and a transmissive substrate 8.

[0031] The wavelength conversion layer 3 and the adhesive layer 7 may have the same configurations as those shown in Fig. 1C. The reflective layer 6 is made of a laminated dielectric multilayer film, and has the properties of reflecting excitation light and transmitting fluorescence whose wavelength has been converted by the wavelength converting particles 4.

[0032] The transmission substrate 8 has the property of transmitting the excitation light and light in the wavelength range of the light, and may be made of a material such as glass or sapphire.

[0033] In terms of optical behavior in the configuration of Figure 1D, excitation light incident from outside is absorbed by the wavelength-converting particles 4 and wavelength-converted to fluorescence. Excitation light that is not absorbed by the wavelength-converting particles 4 passes through the adhesive layer 7 and reaches the reflective layer 6. Because the reflective layer 6 has the property of reflecting excitation light and transmitting fluorescence, excitation light that was not absorbed by the wavelength-converting particles 4 is reflected by the reflective layer 6. The reflected excitation light is again incident on the wavelength-converting particles 4 and absorbed by them, with some or all of it being wavelength-converted to fluorescence. Again, excitation light that has not been wavelength-converted is emitted to the outside at the upper side of the drawing.

[0034] The wavelength-converted fluorescence is completely diffused and emitted in all directions. Fluorescence emitted toward the side where the excitation light was incident is emitted directly to the outside. Fluorescence emitted toward the transparent substrate 8 passes through the adhesive layer 7, the reflective layer 6, and the transparent substrate 8, and is emitted to the outside at the bottom of the drawing.

[0035] (Variation 4) Fig. 1E is a diagram showing Variation 4 of the wavelength conversion particles 4 included in the phosphor wheel according to the present embodiment, illustrating another example of a transmissive configuration. In the example configuration shown in Fig. 1E, excitation light is incident from the upper side of the drawing, and fluorescence is emitted outward from the lower side of the drawing. In order from the excitation light incident side, a transmissive substrate 8, a reflective layer 6, an adhesive layer 7, and a wavelength conversion layer 3 form a layer structure.

[0036] The transparent substrate 8, adhesive layer 7, and wavelength conversion layer 3 may have the same configurations as those shown in Fig. 1D. The reflective layer 6 is made of a laminated dielectric multilayer film, and has the properties of transmitting excitation light and reflecting fluorescence whose wavelength has been converted by the wavelength converting particles 4.

[0037] In the optical behavior of the configuration of Figure 1E, excitation light incident from the outside passes through the transparent substrate 8, the reflective layer 6, and the adhesive layer 7, and reaches the wavelength conversion layer 3. The excitation light is absorbed by the wavelength conversion particles 4 and wavelength-converted to fluorescence. The wavelength-converted fluorescence is emitted in all directions. Fluorescence emitted in the downward direction of the drawing is emitted to the outside below the drawing. Fluorescence emitted toward the transparent substrate 8 reaches the reflective layer 6. The reflective layer 6 has the property of transmitting excitation light and reflecting fluorescence, so the fluorescence is reflected by the reflective layer 6, travels in the downward direction of the drawing, and is emitted to the outside. Excitation light that could not be absorbed by the wavelength conversion particles 4 is emitted below the drawing.

[0038] [Configuration Examples of Phosphor Wheel] The above describes five configuration examples (three reflective and two transmissive) around the wavelength conversion particles 4. Below, configuration examples of phosphor wheel 10 including these configuration examples will be described.

[0039] 2A is a schematic diagram showing an example of the configuration of phosphor wheel 10a according to this embodiment, where the upper side of the drawing is a view from above along the Z axis, and the lower side of the drawing is a cross-sectional view from the side along the Y axis. Phosphor wheel 10a is a rotary wavelength conversion device. Phosphor wheel 10a is configured to be rotatable, with motor 19 provided at the center of circular substrate 11.

[0040] An adhesive layer 12 is provided on one side of the substrate 11 (the upper surface in the case of the cross-sectional view of FIG. 2A ) in the shape of a ring at the same distance from the center of the substrate 11. Furthermore, a wavelength conversion layer 13 is provided on the adhesive layer 12 in the shape of a ring at the same distance from the center of rotation of the substrate 11.

[0041] The configuration example of the phosphor wheel 10a in Fig. 2A is applicable to the layer structures of the reflective embodiments shown in Fig. 1A to Fig. 1C. Therefore, the wavelength conversion layer 13 corresponds to the wavelength conversion layer 3 shown in Fig. 1A to Fig. 1C. The adhesive layer 12 corresponds to the adhesive layer 2 in Fig. 1A or the reflective layer 6 and adhesive layer 7 in Fig. 1B and Fig. 1C.

[0042] In the configuration example of Fig. 2A, in the cross-sectional view at the bottom of the drawing, excitation light enters the wavelength conversion layer 13 from above, and fluorescence is emitted upward. The excitation light and fluorescence are combined to form light in a predetermined wavelength range. For example, if the light in the predetermined wavelength range is white light, the wavelength conversion particles 4 contained in the wavelength conversion layer 13 may be YAG, which converts the wavelength of blue excitation light into yellow fluorescence.

[0043] (Variation 1) Fig. 2B is a schematic diagram showing an example of the configuration of phosphor wheel 10b as Variation 1 according to the present embodiment. The upper side of the drawing is a cross-sectional view seen from the side along the Y axis, and the lower side of the drawing is a view seen from below along the Z axis. Phosphor wheel 10b is a rotary wavelength conversion device. A motor 19 is provided at the center of circular substrate 11, making it rotatable.

[0044] An adhesive layer 12 is provided on one side of the substrate 11 (the bottom surface in the case of the cross-sectional view of FIG. 2B ) in the shape of a ring at the same distance from the center of the substrate 11. Furthermore, a wavelength conversion layer 13 is provided on the adhesive layer 12 in the shape of a ring at the same distance from the center of rotation of the substrate 11.

[0045] The configuration example of the phosphor wheel 10b in Fig. 2B is applicable to the layer structures of the transmissive embodiments shown in Fig. 1D to Fig. 1E. Therefore, the wavelength conversion layer 13 corresponds to the wavelength conversion layer 3 shown in Fig. 1D to Fig. 1E. The adhesive layer 12 corresponds to the reflective layer 6 and adhesive layer 7 shown in Fig. 1D and Fig. 1E. The substrate 11 corresponds to the transmissive substrate 8.

[0046] In the configuration example of Fig. 2B, in the cross-sectional view at the top of the drawing, excitation light is incident from above and fluorescence is emitted downward (when the configuration example shown in Fig. 1E is applied), or excitation light is incident from below and fluorescence is emitted upward (when the configuration example shown in Fig. 1D is applied).

[0047] (Variation 2) Fig. 2C is a schematic diagram showing an example of the configuration of phosphor wheel 10c as variation 2 according to the present embodiment. The upper side of the drawing is a view seen from above along the Z axis, and the lower side of the drawing is a cross-sectional view seen from the side along the Y axis. Phosphor wheel 10c is a rotary wavelength conversion device. A motor 19 is provided at the center of circular substrate 11, making it rotatable.

[0048] An adhesive layer 12 is provided on one side of the substrate 11 (the upper side in the cross-sectional view of FIG. 2C ) in the shape of a ring at the same distance from the center of the substrate 11. Furthermore, wavelength conversion layers 14 and 15 are provided on the adhesive layer 12 in the shape of a ring at the same distance from the center of rotation of the substrate 11. The difference from FIG. 2A is that in the configuration of FIG. 2C , part of the ring of the adhesive layer 12 and the wavelength conversion layers 14 and 15 is an empty space. In the configuration of FIG. 2C , two empty spaces are provided in part of the ring. Two regions formed by the adhesive layer 12 and the wavelength conversion layers 14 and 15 are provided as a pair. Note that the number and arrangement of these regions are merely examples, and three or more regions may be arranged in an annular shape.

[0049] The wavelength conversion layers 14 and 15 convert the wavelength of the same excitation light into light of different wavelength ranges and emit fluorescence. The wavelength conversion particles contained therein may be, for example, a combination of YAG, which converts the wavelength of blue excitation light into yellow fluorescence, LuAG, which converts the wavelength into green fluorescence, and LYSN, which converts the wavelength into red fluorescence. The types and combinations of wavelength conversion particles are not limited to those described above, and any material that achieves the desired wavelength conversion may be used.

[0050] The configuration example of the phosphor wheel 10c in Fig. 2C is applicable to the layer structures of the reflective embodiments shown in Fig. 1A to Fig. 1C. Therefore, the wavelength conversion layers 14 and 15 correspond to the wavelength conversion layer 3 in Fig. 1A to Fig. 1C. The adhesive layer 12 corresponds to the adhesive layer 2 in Fig. 1A or the reflective layer 6 and adhesive layer 7 in Fig. 1B and Fig. 1C.

[0051] In the configuration example of FIG. 2C, in the cross-sectional view at the bottom of the drawing, excitation light enters from above, and fluorescence is emitted toward the top.

[0052] (Variation 3) Fig. 2D is a schematic diagram showing a configuration example of a phosphor wheel 10d as Variation 3 according to the present embodiment. The upper side of the drawing is a view seen from above along the Z axis, and the lower side of the drawing is a cross-sectional view seen from the side along the Y axis. The phosphor wheel 10d is a rotary wavelength conversion device. A motor 19 is provided at the center of a circular substrate 11, making it rotatable.

[0053] An adhesive layer 12 is provided on one side of the substrate 11 (the top surface in the cross-sectional view of FIG. 2D ) in the shape of a ring at the same distance from the center of the substrate 11. Furthermore, wavelength conversion layers 14 and 15 are provided on the adhesive layer 12 in the shape of a ring at the same distance from the center of rotation of the substrate 11. The difference from FIG. 2C is that in the configuration of FIG. 2D , a portion of the rings of the adhesive layer 12 and the wavelength conversion layers 14 and 15 is formed by a reflective layer 16. In the configuration of FIG. 2D , two reflective layer 16 regions are provided. Two regions formed by the adhesive layer 12 and the wavelength conversion layers 14 and 15 are provided as a pair. The number and arrangement of these regions are merely examples, and three or more reflective layer regions may be arranged in a ring shape. The wavelength conversion layers 14 and 15 may have a configuration similar to that of FIG. 2C .

[0054] The configuration example of phosphor wheel 10d in Fig. 2D is applicable to the layer structures of the reflective embodiments shown in Fig. 1A to Fig. 1C. Therefore, wavelength conversion layers 14 and 15 correspond to wavelength conversion layer 3 in Fig. 1A to Fig. 1C. Also, adhesive layer 12 corresponds to adhesive layer 2 in Fig. 1A or reflective layer 6 and adhesive layer 7 in Fig. 1B and Fig. 1C.

[0055] In the configuration example of Fig. 2D, in the cross-sectional view at the bottom of the drawing, excitation light is incident from above and fluorescence is emitted toward the top. In the configuration of Fig. 2D, it is possible to switch between reflection of excitation light by the reflective layer 16 and reflection of light of a predetermined wavelength by the adhesive layer 12.

[0056] (Variation 4) Fig. 2E is a schematic diagram showing an example of the configuration of a phosphor wheel 10e as Variation 4 according to the present embodiment. The upper side of the drawing is a view seen from above along the Z axis, and the lower side of the drawing is a cross-sectional view seen from the side along the Y axis. The phosphor wheel 10e is a rotary wavelength conversion device. A motor 19 is provided at the center of a circular substrate 11, making it rotatable.

[0057] An adhesive layer 12 is provided on one side of the substrate 11 (the upper surface in the cross-sectional view of FIG. 2E ) in the shape of a ring at the same distance from the center of the substrate 11. Furthermore, wavelength conversion layers 14 and 15 are provided on the adhesive layer 12 in the shape of rings at the same distance from the center of rotation of the substrate 11. The difference from FIG. 2C is that the configuration of FIG. 2E has openings 17 in parts of the rings of the adhesive layer 12 and the wavelength conversion layers 14 and 15. In the configuration of FIG. 2E , two opening 17 regions are provided. Two regions formed by the adhesive layer 12 and the wavelength conversion layers 14 and 15 are provided as a pair. The number and arrangement of these regions are merely examples, and three or more openings 17 may be arranged in a ring shape.

[0058] The configuration example of the phosphor wheel 10e in Fig. 2E is applicable to the layer structures of the reflective embodiments shown in Fig. 1A to Fig. 1C. Therefore, the wavelength conversion layers 14 and 15 correspond to the wavelength conversion layer 3 in Fig. 1A to Fig. 1C. The adhesive layer 12 corresponds to the adhesive layer 2 in Fig. 1A or the reflective layer 6 and adhesive layer 7 in Fig. 1B and Fig. 1C.

[0059] In the configuration example of Fig. 2E, in the cross-sectional view at the bottom of the drawing, excitation light enters from above and fluorescence is emitted toward the top. The wavelength conversion layers 14 and 15 may have a configuration similar to that of Fig. 2C. In the configuration of Fig. 2E, the opening 17 can be configured to allow passage of excitation light and the adhesive layer 12 can be configured to reflect light of a predetermined wavelength.

[0060] (Variation 5) Fig. 2F is a schematic diagram showing an example of the configuration of a phosphor wheel 10f as Variation 5 according to the present embodiment. The upper side of the drawing is a view seen from above along the Z axis, and the lower side of the drawing is a cross-sectional view seen from the side along the Y axis. The phosphor wheel 10f is a rotary wavelength conversion device. A motor 19 is provided at the center of a circular substrate 11, making it rotatable.

[0061] An adhesive layer 12 is provided on one side of the substrate 18 (the upper side in the case of the cross-sectional view of FIG. 2F) in the shape of a ring at the same distance from the center of the substrate 18. Furthermore, wavelength conversion layers 14 and 15 are provided on the adhesive layer 12 in the shape of rings at the same distance from the center of rotation of the substrate 18. The difference from FIG. 2C is that the configuration of FIG. 2F is that the substrate 18 is a transmissive substrate. That is, the phosphor wheel 10f corresponds to a transmissive phosphor wheel.

[0062] The configuration example of the phosphor wheel 10f in Figure 2F is applicable to the layer structures of the transmissive embodiments shown in Figures 1D to 1E. Therefore, the wavelength conversion layers 14 and 15 correspond to the wavelength conversion layer 3 in Figures 1A to 1E. The adhesive layer 12 corresponds to the reflective layer 6 and adhesive layer 7 in Figures 1D and 1E. The substrate 18 corresponds to the transmissive substrate 8.

[0063] In the configuration example of Figure 2F, in the cross-sectional view at the top of the drawing, excitation light enters from above and fluorescence is emitted downward (when the configuration example shown in Figure 1D is applied). Alternatively, excitation light enters from below and fluorescence is emitted upward (when the configuration example shown in Figure 1E is applied). The wavelength conversion layers 14 and 15 may have a configuration similar to that of Figure 2C. In the configuration of Figure 2F, excitation light irradiated on areas other than the wavelength conversion layers 14 and 15 and the adhesive layer 12 is transmitted through the substrate 18.

[0064] [Light Source Device] The above has been described with reference to six exemplary configurations of the phosphor wheel 10. Below, an example of a light source device 100 including these exemplary configurations of the phosphor wheel 10 will be described.

[0065] 3A is a schematic diagram showing a configuration example of a light source device 100a including phosphor wheel 10 according to the present embodiment. In this example, the phosphor wheel 131 included in light source device 100a is the reflective phosphor wheel 10a shown in FIG. 2A.

[0066] Laser light in the blue wavelength range emitted from multiple laser light sources 101 is collimated by multiple collimator lenses 102 provided corresponding to each of the multiple laser light sources 101. The collimated blue light is incident on a subsequent convex lens 103, where its beam width is reduced, and then incident on a subsequent diffuser plate 104, where it is diffused, improving the uniformity of the light. The blue light, whose uniformity has been improved, is incident on a subsequent concave lens 105, where it is converted into a parallel beam, and then incident on a dichroic mirror 107.

[0067] Dichroic mirror 107 has the property of transmitting only blue light and reflecting fluorescent light. Blue light from laser light source 101 is incident on dichroic mirror 107, which has the property of transmitting blue light, and passes through it as is, and then enters convex lens 141.

[0068] Furthermore, laser light in the blue wavelength range emitted from the multiple laser light sources 111 is collimated by multiple collimator lenses 112 provided corresponding to each of the multiple laser light sources 111. The collimated blue light is incident on the subsequent convex lens 113, where its beam width is reduced, and then incident on the subsequent diffuser plate 114, where it is diffused, improving the uniformity of the light. The blue light, whose uniformity has been improved, is incident on the subsequent concave lens 115, where it is converted into a parallel beam, and then incident on the dichroic mirror 107. Because dichroic mirror 107 has the property of transmitting blue light, the incident blue light is transmitted as is and enters convex lenses 121 and 122, and is then condensed on the wavelength conversion layer of phosphor wheel 131 (in this example, wavelength conversion layer 13 of phosphor wheel 10a).

[0069] The blue light collected on wavelength conversion layer 13 is wavelength-converted to become fluorescent light, which changes its traveling direction by 180 degrees and enters convex lenses 122 and 121 again to be collimated. The collimated light then enters dichroic mirror 107, which has the above-mentioned property of reflecting fluorescent light, and its traveling direction is changed by 90 degrees.

[0070] The blue light that has passed through dichroic mirror 107 and the reflected fluorescent light are combined to form white light. The white light enters convex lens 141 and then enters rod integrator 142, which is disposed near the light-collecting position. Rod integrator 142 irradiates the light onto a desired area outside light source device 100a.

[0071] 3B is a schematic diagram showing an example of a light source device 100b as a first modification of the present embodiment. In this example, the phosphor wheel 231 included in the light source device 100b is the reflective phosphor wheel 10a shown in FIG. 2A.

[0072] Laser light in the blue wavelength range emitted from multiple laser light sources 101 is collimated by multiple collimator lenses 102 provided corresponding to each of the multiple laser light sources 101. The collimated blue light is incident on a subsequent convex lens 103, where its beam width is reduced, and then incident on a subsequent diffuser plate 104, where it is diffused, improving the uniformity of the light. The blue light, whose uniformity has been improved, is incident on a subsequent concave lens 105, where it is converted into a parallel beam, and then incident on a phase difference plate 106.

[0073] The retardation plate 106 rotates the polarization direction of the blue light by delaying the phase by 1 / 2λ. The slow axis of this polarizer is optimized according to the ratio of S-polarized light and P-polarized light, depending on the ratio of blue light and fluorescent light. The dichroic mirror 207 has the property of reflecting S-polarized blue light and transmitting P-polarized light and fluorescent light.

[0074] The S-polarized light that has exited phase difference plate 106 is incident on and reflected by dichroic mirror 207, which has the property of reflecting S-polarized blue light, and its traveling direction is changed by 90 degrees. The reflected S-polarized light is incident on convex lenses 121 and 122 and concentrated, and then incident on the wavelength conversion layer of phosphor wheel 231 (in this example, wavelength conversion layer 13 of phosphor wheel 10a).

[0075] The blue light incident on wavelength conversion layer 13 of phosphor wheel 231 is wavelength-converted to become fluorescent light, which then changes its traveling direction by 180 degrees before being emitted. The fluorescent light then enters convex lenses 122 and 121, where it is converted into a parallel beam, and enters dichroic mirror 207. Dichroic mirror 207 has the property of transmitting fluorescent light, so the incident fluorescent light continues to travel as is.

[0076] Furthermore, the P-polarized light that has exited phase difference plate 106 is incident on dichroic mirror 207 that has the property of transmitting P-polarized blue light, and then travels directly to be incident on phase difference plate 208 .

[0077] Retardation plate 208 has the property of delaying the phase by 1 / 4λ and converting the polarization direction of blue light from P-polarized light to circularly polarized light. The P-polarized blue light incident on retardation plate 208 is converted to circularly polarized light, and is reflected by total reflection mirror 241, changing its traveling direction by 180 degrees. The P-polarized blue light then enters retardation plate 208 and is converted from circularly polarized light to S-polarized light.

[0078] The S-polarized blue light that has exited phase difference plate 208 is reflected by dichroic mirror 207, which has the property of reflecting S-polarized blue light, and is emitted with the traveling direction of the light changed by 90 degrees.

[0079] The combined light of the blue light and the fluorescence emitted from the dichroic mirror 207 is homogenized by a pair of fly-eye lenses 242 and 244 sandwiching a total reflection mirror 243 therebetween. The homogenized combined light then has its polarization unified by a polarization conversion array 245 on the exit side of the fly-eye lens 244, and is emitted to the outside of the light source device 100b. Note that further modifications may be made, such as changing the positions of the phosphor wheel 231 and the total reflection mirror 241 to change the characteristics of the dichroic mirror 207.

[0080] 3C is a schematic diagram showing an example of a light source device 100c as Modification 2 of the present embodiment. In this example, the light source device 100c will be described using the transmissive phosphor wheel 10b shown in FIG. 2B as the phosphor wheel 331 included in the light source device 100c.

[0081] Laser light in the blue wavelength range emitted from multiple laser light sources 101 is collimated by multiple collimator lenses 102 provided corresponding to each of the multiple laser light sources 101. The collimated blue light enters subsequent convex lens 103, where its beam width is reduced, and then enters subsequent diffuser plate 104 where it is diffused, improving the uniformity of the light. The blue light with improved uniformity enters subsequent concave lens 105, and is then focused by convex lenses 121 and 122 on the wavelength conversion layer of phosphor wheel 331 (in this example, wavelength conversion layer 13 of phosphor wheel 10b).

[0082] A portion of the blue light incident on the wavelength conversion layer 13 of the phosphor wheel 331 is wavelength converted to fluorescence, and is combined with the blue light that has not been wavelength converted. The combined light then enters the rod integrator 142, is homogenized, and is emitted from the rod integrator 142 to the outside of the light source device 100c.

[0083] 3D is a schematic diagram showing an example of a light source device 100d as a modification 3 of the present embodiment. In this example, the light source device 100d will be described using the transmissive phosphor wheel 10b shown in FIG. 2B as the phosphor wheel 431 included in the light source device 100d.

[0084] Laser light in the blue wavelength range emitted from multiple laser light sources 101 is collimated by multiple collimator lenses 102 provided corresponding to each of the multiple laser light sources 101. The collimated blue light enters subsequent convex lens 103, where its beam width is reduced, and then enters subsequent diffuser plate 104 where it is diffused, improving the uniformity of the light. The blue light with improved uniformity enters subsequent concave lens 105, and is then focused by convex lenses 121 and 122 on the wavelength conversion layer of phosphor wheel 331 (in this example, wavelength conversion layer 13 of phosphor wheel 10b).

[0085] A portion of the blue light incident on the wavelength conversion layer 13 of the phosphor wheel 331 is wavelength converted to fluorescence, which is then combined with the blue light that has not been wavelength converted and incident on the convex lenses 412 and 411 to be collimated.

[0086] The combined light of the blue light and the fluorescent light that has been emitted from the convex lenses 412 and 411 and converted into parallel light is homogenized by a pair of fly-eye lenses 242 and 244 sandwiching a total reflection mirror 243 therebetween. The combined light then has its polarization unified by a polarization conversion array 245 on the emission side of the fly-eye lens 244, and is emitted to the outside of the light source device 100d.

[0087] 3E is a schematic diagram showing an example of a light source device 100e as a fourth modification of the present embodiment. In this example, the light source device 100e will be described using the reflective phosphor wheel 10c shown in FIG. 2C as the phosphor wheel 531 included in the light source device 100e.

[0088] Laser light in the blue wavelength range emitted from the multiple laser light sources 101 is collimated by multiple collimator lenses 102 provided corresponding to each of the multiple laser light sources 101. The collimated blue light is incident on the subsequent diffuser plate 104 and diffused, improving the uniformity of the light. The blue light with improved uniformity is incident on the subsequent dichroic mirror 507.

[0089] Dichroic mirror 507 has a reflecting surface 508 that reflects the blue light from laser light source 101 and a transmitting area, and has the property of transmitting fluorescence resulting from wavelength conversion of light from laser light source 101 by phosphor wheel 531, which will be described later. Excitation light incident on dichroic mirror 507 is incident on reflecting surface 508 provided on a part of the surface, and its traveling direction is changed by 90 degrees.

[0090] The light from laser light source 101, whose direction of travel has been changed by 90 degrees, enters convex lens 141 and is focused on the surface of color wheel 581. Color wheel 581 has a layer that transmits the blue light from laser light source 101, and optical properties that reflect the blue light and transmit some or all of the fluorescence wavelength-converted by phosphor wheel 531. Color wheel 581 is synchronized with phosphor wheel 531 using a synchronization circuit (not shown), and is controlled to emit light of different wavelengths in a time series according to predetermined specifications.

[0091] First, the light that passes through the layer that transmits blue light of the color wheel 581 is incident on the rod integrator 142 at the subsequent stage, where it is homogenized, and is emitted to the subsequent stage of the light source device 100e.

[0092] Subsequently, the light incident on the layer of color wheel 581 that reflects blue light from laser light source 101 changes its traveling direction by 180 degrees and passes through a portion of dichroic mirror 507 that does not have reflective surface 508. As a result, the light is incident on subsequent convex lenses 121 and 122, where it is condensed, and then incident on the wavelength conversion layers of phosphor wheel 531 (in this example, wavelength conversion layers 14 and 15 of phosphor wheel 10c). The blue light from laser light source 101 that has entered wavelength conversion layers 14 and 15 is wavelength-converted to fluorescence, which then changes its traveling direction by 180 degrees and is emitted.

[0093] The fluorescence emitted from phosphor wheel 531 passes through convex lenses 122 and 121, is converted into parallel light, and is incident on dichroic mirror 507. Since dichroic mirror 507 has the property of transmitting fluorescence, the fluorescence passes through as is, is incident on convex lens 141, and is incident on color wheel 581.

[0094] As described above, color wheel 581 has the property of transmitting some or all of the fluorescence wavelength-converted by phosphor wheel 531. Color wheel 581 is synchronized using a synchronization circuit (not shown), and emits light of a predetermined wavelength range from the incident light in a time-series manner. The light is then homogenized by rod integrator 142 and emitted.

[0095] As a result, in the light source device 100e, the rod integrator 142 emits blue light and fluorescent light from the laser light source 101 in a predetermined wavelength range to the outside in a time series manner.

[0096] 3F is a schematic diagram showing an example of a light source device 100f as Modification 5 according to the present embodiment. In this example, the reflective phosphor wheel 10d shown in FIG. 2D will be used for explanation.

[0097] Laser light in the blue wavelength range emitted from multiple laser light sources 101 is collimated by multiple collimator lenses 102 provided corresponding to each of the multiple laser light sources 101. The collimated blue light enters the subsequent convex lens 103, where its beam width is reduced, and then enters the subsequent diffuser plate 104 where it is diffused and the uniformity of the light is improved. The blue light with the improved uniformity of the light enters the subsequent concave lens 105 and is converted into a parallel beam.

[0098] The blue light collimated by the concave lens 105 enters the retardation plate 106. The retardation plate 106 has the function of rotating the polarization axis of the linearly polarized light by delaying the phase by ½λ. By optimally adjusting the direction of the slow axis of the retardation plate 106, the polarization direction of the excitation light emitted from the laser light source 101 is aligned with the S-polarization direction. The S-polarized excitation light then enters the dichroic mirror 607, which is tilted at approximately 45 degrees with respect to the optical axis.

[0099] The dichroic mirror 607 has the property of reflecting blue S-polarized light, which is the excitation light aligned by the phase difference plate 106, and transmitting blue P-polarized light and light in the wavelength range of the fluorescence wavelength-converted by the phosphor wheel 631.

[0100] The excitation light from the laser light source 101, which has been aligned to S-polarized light, enters the dichroic mirror 607, which changes the direction of travel of the light by 90 degrees, and then enters the retardation plate 608. The retardation plate 608 has the property of converting linearly polarized light into circularly polarized light by delaying the polarization direction of the excitation light by ¼λ. The excitation light, whose polarization direction has been converted into circularly polarized light after passing through the retardation plate 608, is focused in time series by a focusing system consisting of two convex lenses 121 and 122 onto a wavelength conversion layer and a reflective layer, which are provided at the same distance from the center of rotation on the phosphor wheel 631.

[0101] Below, we will provide a detailed explanation of the behavior of light when it enters the wavelength conversion layer (in this example, wavelength conversion layers 14 and 15 of phosphor wheel 10d) and when it enters the reflective layer (in this example, reflective layer 16 of phosphor wheel 10d) in phosphor wheel 631 (phosphor wheel 10d).

[0102] The excitation light incident on the wavelength conversion layers 14 and 15 of the phosphor wheel 631 undergoes wavelength conversion, and fluorescent light having different wavelength ranges is emitted by changing the traveling direction of the light by 180 degrees.

[0103] The fluorescence emitted from the phosphor wheel 631 is again incident on the two convex lenses 122 and 121 to be converted into parallel light, then incident on the phase difference plate 608 to rotate the polarization direction, and then incident on the dichroic mirror 607 .

[0104] As described above, dichroic mirror 607 has the property of transmitting fluorescence, so the incident fluorescence passes through as is and enters convex lens 141. Furthermore, excitation light incident on reflective layer 16 of phosphor wheel 631 is reflected as is, and then emitted after changing the traveling direction of the light by 180 degrees.

[0105] The excitation light reflected by the phosphor wheel 631 is again incident on the two convex lenses 122 and 121, where it is converted into parallel light, and then incident on the phase difference plate 608. The phase difference plate 608 retards the polarization direction of the light by ¼λ, thereby rotating the polarization direction from circularly polarized light to P-polarized light, and the light then enters the dichroic mirror 607.

[0106] As described above, dichroic mirror 607 has the property of transmitting P-polarized excitation light, and therefore the incident excitation light passes through as is and enters convex lens 141. The fluorescence and excitation light incident on convex lens 141 are condensed, pass through color wheel 581, and are condensed near the entrance end of rod integrator 142, which will be described later.

[0107] The color wheel 581 is synchronized with the phosphor wheel 631 using a synchronization circuit (not shown). The color wheel 581 is configured with multiple filters having spectral characteristics that transmit some or all wavelengths of blue light and fluorescent light in accordance with the characteristics of the optical system. Specifically, the color wheel 581 is configured with multiple filters that transmit yellow, green, and red by transmitting all of the fluorescent light from the phosphor wheel 631 or by reflecting some of the light and transmitting the rest, as well as an area that transmits blue light unchanged. The configuration of the color filter wheel is not limited to the configuration described above and may be modified as appropriate to suit the specifications of the phosphor wheel, light source device, and projection-type image display device.

[0108] The light beams having different wavelength bands incident on rod integrator 142 in a time-division manner are homogenized by rod integrator 142 and emitted from the emission end to a subsequent stage. In this example, color wheel 581 is disposed near the entrance side of rod integrator 142, but it may also be disposed near the emission side.

[0109] 3G is a schematic diagram showing an example of a light source device 100g as a sixth modification of the present embodiment. In this example, the reflective phosphor wheel 10d shown in FIG. 2D is used as the phosphor wheel 731 included in the light source device 100g.

[0110] Laser light in the blue wavelength range emitted from the multiple laser light sources 101 is collimated by multiple collimator lenses 102 provided corresponding to each of the multiple laser light sources 101. The collimated blue light is incident on the subsequent diffuser plate 104 and diffused, improving the uniformity of the light. The blue light with improved uniformity is incident on the subsequent dichroic mirror 707.

[0111] Dichroic mirror 707 has a reflective surface 708 that reflects blue light from laser light source 101 and a transmissive area, and has the property of transmitting fluorescence obtained by wavelength-converting light from laser light source 101 by phosphor wheel 731 (described later). Light incident on dichroic mirror 707 is incident on reflective surface 708 provided on a portion of its surface, and its traveling direction is changed by 90 degrees. The light then enters convex lenses 121 and 122, where it is condensed, and then enters the wavelength conversion layers of phosphor wheel 731 (wavelength conversion layers 14 and 15 of phosphor wheel 10d in this example) and the reflective layer (reflective layer 16 of phosphor wheel 10d in this example).

[0112] The behavior of light when it is incident on the wavelength conversion layers 14 and 15 and when it is incident on the reflective layer 16 in the phosphor wheel 731 (phosphor wheel 10d) will be described in detail below.

[0113] The excitation light incident on the wavelength conversion layers 14 and 15 of the phosphor wheel 731 is wavelength-converted into fluorescence having different wavelength ranges, and the fluorescence is emitted after changing its direction of travel by 180 degrees. The fluorescence emitted from the phosphor wheel 731 is again incident on the two convex lenses 122 and 121, where it is converted into parallel light, and then enters the dichroic mirror 707.

[0114] As described above, dichroic mirror 707 has the property of transmitting fluorescence, so the incident fluorescence passes through it as is and enters convex lens 141. Furthermore, excitation light that enters reflective layer 16 of phosphor wheel 731 is reflected as is, and the light's direction of travel is changed by 180 degrees before it is emitted. The excitation light reflected by phosphor wheel 731 enters two convex lenses 122 and 121 again, where it is converted into parallel light, and then enters dichroic mirror 707.

[0115] As described above, dichroic mirror 707 has the property of transmitting blue light in a region other than blue light reflecting surface 708, and therefore blue light incident on this transmission region passes through as is and enters convex lens 141. The fluorescence and excitation light incident on convex lens 141 are condensed, pass through color wheel 581, and are condensed near the entrance end of rod integrator 142.

[0116] The light beams having different wavelength bands incident on rod integrator 142 in a time-division manner are homogenized by rod integrator 142 and emitted from the emission end. In this description, color wheel 581 is placed near the entrance side of rod integrator 142, but it may also be placed near the emission side.

[0117] 3H is a schematic diagram showing an example of a light source device 100h as Modification 7 according to the present embodiment. In this example, the reflective phosphor wheel 10e shown in FIG. 2E is used as the phosphor wheel 831 included in the light source device 100h.

[0118] Laser light in the blue wavelength range emitted from the multiple laser light sources 101 is collimated by multiple collimator lenses 102 provided corresponding to each of the multiple laser light sources 101. The collimated blue light enters the subsequent convex lens 103, where its beam width is reduced, and then enters the subsequent diffuser plate 104 where it is diffused and the uniformity of the light is improved. The blue light with improved uniformity enters the subsequent concave lens 105 and is made into a parallel beam. The parallelized blue light from the laser light sources 101 enters the dichroic mirror 807.

[0119] Dichroic mirror 807 has the property of reflecting blue light from laser light source 101 and transmitting fluorescence obtained by wavelength-converting the blue light from laser light source 101 by phosphor wheel 831, which will be described later. Light from laser light source 101 that is incident on dichroic mirror 807 is reflected, changes its traveling direction by 90 degrees, and enters convex lenses 121 and 122, and is focused on the wavelength conversion layer of phosphor wheel 831 (wavelength conversion layers 14 and 15 of phosphor wheel 10e in this example) and an opening (opening 17 of phosphor wheel 10e in this example).

[0120] Hereinafter, the behavior of light collected on the wavelength conversion layers 14 and 15 and the opening 17 of the phosphor wheel 831 (phosphor wheel 10e) will be described in detail.

[0121] The blue light from laser light source 101 that is focused on wavelength conversion layers 14 and 15 is wavelength-converted to become fluorescent light, and the light's direction of travel is changed by 180 degrees before it is incident on convex lenses 122 and 121 again and converted into parallel light. The fluorescent light then again enters dichroic mirror 807. As described above, dichroic mirror 807 has the property of transmitting fluorescent light, so the fluorescent light continues traveling as is, entering convex lens 141 and then entering color wheel 581.

[0122] Furthermore, the blue light from laser light source 101 that is condensed at aperture 17 passes directly through phosphor wheel 831 and then passes through convex lenses 812 and 811 to be collimated. Thereafter, the light's direction of travel is changed by 270 degrees by a relay system made up of total reflection mirrors 813, 815, and 817 and convex lenses 814, 816, and 818, and the light is incident on dichroic mirror 807 from a direction 180 degrees opposite to the light incident from laser light source 101 described above. As described above, dichroic mirror 807 has the property of reflecting the blue light from laser light source 101, so the light's direction of travel is changed by 90 degrees, and the blue light is incident on convex lens 141 and then on color wheel 581.

[0123] Color wheel 581 is synchronized with phosphor wheel 831 by a synchronization circuit (not shown). Color wheel 581 is composed of regions that transmit blue light and regions that transmit the entire wavelength range of fluorescent light and a portion of the wavelength range, and emits light of different wavelengths in a time series according to predetermined specifications. The light emitted from color wheel 581 enters rod integrator 142 in the subsequent stage, where it is homogenized and emitted.

[0124] 3I is a schematic diagram showing another example of light source device 100i as Modification 8 of the present embodiment. In this example, the light source device 100i will be described using the transmissive phosphor wheel 10f shown in FIG. 2F as the phosphor wheel 931 included in the light source device 100i.

[0125] Laser light in the blue wavelength range emitted from multiple laser light sources 101 is collimated by multiple collimator lenses 102 provided corresponding to each of the multiple laser light sources 101. The collimated blue light enters the subsequent convex lens 103, where its beam width is reduced, and then enters the subsequent diffuser plate 104, where it is diffused and the uniformity of the light is improved. The blue light, whose uniformity has been improved, enters the subsequent concave lens 105, where it is converted into a parallel beam. The blue light emitted from concave lens 105 is concentrated by convex lenses 121 and 122 and concentrated on the wavelength conversion layer of phosphor wheel 931 (in this example, wavelength conversion layers 14 and 15 of phosphor wheel 10f) and on the substrate without a wavelength conversion layer (in this example, substrate 18 of phosphor wheel 10f).

[0126] Hereinafter, the behavior of light focused on the wavelength conversion layers 14 and 15 and the substrate 18 of the phosphor wheel 931 (phosphor wheel 10f) will be described in detail.

[0127] The blue light from the laser light source 101 that is focused on the wavelength conversion layers 14 and 15 is wavelength converted, and the wavelength-converted fluorescence travels as is, passing through and exiting the phosphor wheel 931. The blue light from the laser light source 101 that is focused on the region of the substrate 18 other than the wavelength conversion layers 14 and 15 travels as is, passing through and exiting the phosphor wheel 931. The blue light and fluorescence that have exited the phosphor wheel 931 are focused by a relay system made up of convex lenses 911, 912, and 913, and are focused on and incident on the color wheel 581.

[0128] The color wheel 581 is synchronized with the phosphor wheel 10f by a synchronization circuit (not shown), and is configured with an area that transmits blue light and an area that transmits the entire wavelength range of fluorescent light and some of the wavelengths. The color wheel 581 emits light of different wavelengths in a time series according to predetermined specifications. The light that has exited the color wheel 581 enters the rod integrator 142 in the subsequent stage, where it is homogenized and output to the subsequent stage.

[0129] [Projection-Type Image Display Device] The above has been described with reference to nine configuration examples of the light source device 100. Below, an example of a projection-type image display device 200 that includes these configuration examples will be described.

[0130] 4A is a schematic diagram showing an example of the configuration of a projection-type image display device 200a including a light source device 100 according to the present embodiment. In this example, the light source device included in the projection-type image display device 200a will be described using the light source device 100a shown in FIG. 3A.

[0131] Light that has exited rod integrator 142, which is the final stage of light source device 100a, then enters a relay lens system made up of three convex lenses 143, 144, and 145. The light that has exited the relay lens system made up of convex lenses 143, 144, and 145 enters total reflection prism 151. Total reflection prism 151 is made up of two prisms and a tiny gap, and the tiny gap forms total reflection surface 152 that reflects light that is incident at a specific angle or greater. Light that has entered total reflection prism 151 from the relay lens system made up of convex lenses 143, 144, and 145 at an angle greater than the total reflection angle is totally reflected and enters color prism 161.

[0132] Color prism 161 is arranged with a minute gap between it and total reflection prism 151, and is composed of three glass blocks with a minute gap between the second and third glass blocks. It also has a blue-reflecting dichroic mirror on the first glass block side between the first and second glass blocks, and a red-reflecting dichroic mirror between the second and third glass blocks.

[0133] Light of all wavelength ranges that enters color prism 161 passes through the first glass block. Of the light of all wavelength ranges that enters the first glass block, blue light is reflected by a blue-reflecting dichroic mirror formed between the second glass block, changes its direction of travel, and enters and is reflected at an angle equal to or greater than the total reflection angle into a minute gap provided between total reflection prism 151 and color prism 161, and is then guided to digital mirror device (hereinafter referred to as "DMD") 171.

[0134] Of the light of all wavelengths incident on the first glass block, red light passes through the blue-reflecting dichroic mirror formed between the first and second glass blocks, passes through the minute gap between the first and second glass blocks, and enters the second glass block. The red light incident on the second glass block is reflected by the red-reflecting dichroic mirror formed between the second glass block and the third glass block, and is reflected by the minute gap between the first and second glass blocks at an angle greater than the total reflection angle, and is then guided to the DMD 172.

[0135] Of the light of all wavelengths incident on the first glass block, green light passes through a blue-reflecting dichroic mirror formed between the first and second glass blocks, passes through a minute gap between the first and second glass blocks, and enters the second glass block. The green light incident on the second glass block passes through a red-reflecting dichroic mirror formed between the second glass block and the third glass block, passes through the third glass block, and is guided to the DMD 173.

[0136] DMDs 171, 172, and 173 are composed of multiple micromirrors corresponding to pixels, and the direction of travel of light is changed by changing the tilt direction of the micromirrors in response to a video signal from a video circuit (not shown). The green light whose direction has been changed by DMD 173 in response to the video signal reaches the third glass block, passes through a red-reflecting dichroic mirror provided between the third and second glass blocks, the second glass block, a microgap provided between the second and first glass blocks, a blue-reflecting dichroic mirror, and the first glass block, and is then incident on total reflection prism 151.

[0137] Next, the red light, which has changed direction by DMD 172 in response to the video signal, reaches the second glass block, where it is incident on the minute gap between the first and second glass blocks at an angle greater than the total reflection angle, where it is reflected, and then changes direction toward the third glass block. The light traveling toward the third glass block is reflected by the red-reflecting dichroic mirror provided between the second and third glass blocks, where it changes direction, and then passes through the second glass block. At this time, the light passes through the minute gap between the second and first glass blocks at an angle less than the total reflection angle, passes through the blue-reflecting dichroic mirror and the first glass block, and then enters the total reflection prism 151.

[0138] Furthermore, the blue light that has changed its traveling direction by DMD 171 in accordance with the video signal enters the first glass block, enters the minute gap between color prism 161 and total reflection prism 151 at an angle greater than the total reflection angle, and is reflected. The blue light then travels toward the second glass block, where it is reflected by the blue-reflecting dichroic mirror provided between the first and second glass blocks. The blue light then passes through the first glass block, enters and passes through the minute gap between color prism 161 and total reflection prism 151 at an angle less than the total reflection angle, and enters total reflection prism 151.

[0139] As described above, light of all wavelengths whose traveling direction has been changed by DMDs 171, 171, and 173 in response to a video signal is incident on total reflection prism 151 and passes through total reflection surface 152 by being incident at an angle equal to or smaller than the total reflection angle. The light then exits total reflection prism 151 and enters projection lens 191, and is then projected onto a screen (not shown).

[0140] 4B is a schematic diagram showing an example of a projection-type image display device 200b as a modification 1 of the present embodiment. In this example, the light source device included in the projection-type image display device 200b is the light source device 100b shown in FIG. 3B.

[0141] The light with the same polarization direction over the entire wavelength range that has been emitted from the polarization conversion array 245, which is the final stage of the light source device 100b, is incident on the convex lens 246. The blue light that has been emitted to the convex lens 246 is incident on the dichroic mirror 247.

[0142] Dichroic mirror 247 has the property of reflecting blue light and transmitting other light (green and red). Blue light incident on dichroic mirror 247 is reflected, changing its direction of travel by 90 degrees, and then reflected by total reflection mirror 248 located downstream, changing its direction of travel by 90 degrees. Furthermore, the blue light passes through convex lens 256 and polarizing plate 263, and is guided to liquid crystal display (hereinafter referred to as "LCD") 266.

[0143] Next, the green light that has exited convex lens 246 is incident on dichroic mirror 247. As described above, dichroic mirror 247 has the property of transmitting green light, so the green light passes through dichroic mirror 247 and is incident on dichroic mirror 249.

[0144] Dichroic mirror 249 has the property of reflecting green light and transmitting red light. Blue light incident on dichroic mirror 249 is reflected, changes its direction of travel by 90 degrees, passes through convex lens 255 and polarizing plate 262 arranged downstream, and is guided to LCD 265.

[0145] Finally, the red light that has exited convex lens 246 is incident on dichroic mirror 247. As described above, dichroic mirror 247 has the property of transmitting red light, so the incident red light passes through dichroic mirror 247 and then enters dichroic mirror 249. As described above, dichroic mirror 249 has the property of transmitting red light, so the incident red light passes through dichroic mirror 249.

[0146] The red light passing through the dichroic mirror 249 has its direction of travel changed by 180 degrees by a relay lens system consisting of convex lenses 250, 252, and 254 and total reflection mirrors 251 and 253, passes through the convex lens 254 and the polarizing plate 261, and is guided to the LCD 264.

[0147] The three LCDs 264, 265, and 266 are each composed of a plurality of tiny pixels that rotate the polarization direction, and the polarization rotation direction is changed by 90 degrees in accordance with a video signal by a video circuit (not shown). Red light incident on LCD 264 passes through a polarizing plate 267 located downstream thereof and is modulated in accordance with the video signal. Green light incident on LCD 265 passes through a polarizing plate 268 located downstream thereof and is modulated in accordance with the video signal. Blue light incident on LCD 266 passes through a polarizing plate 269 located downstream thereof and is modulated in accordance with the video signal.

[0148] The light transmitted through polarizing plates 267, 268, and 269 enters dichroic prism 270 from three surfaces. Dichroic prism 270 is made up of four glass blocks with dichroic mirrors that reflect only blue and red, and has the property of combining the blue, green, and red light incident from the three surfaces and outputting the combined light from the other surface.

[0149] The blue, green, and red light beams incident on the dichroic prism 270 are combined according to the characteristics described above and then emitted. The emitted light beams enter the projection lens 191 and are then projected onto a screen (not shown). The arrangement of the LCDs corresponding to each light beam is not limited to the above and may be arbitrarily changed.

[0150] 4C is a schematic diagram showing an example of a projection-type image display device 200c as a modification 2 of the present embodiment. In this example, the light source device included in the projection-type image display device 200c will be described using the light source device 100e shown in FIG. 3E.

[0151] The light beams with different wavelength bands emitted from rod integrator 142, which is the final stage of light source device 100e, are then incident on a relay lens system made up of three convex lenses 143, 144, and 145. The light beams that have exited the relay lens system made up of convex lenses 143, 144, and 145 are incident on total reflection prism 151. Total reflection prism 151 is made up of two prisms and a minute gap, and the minute gap serves as total reflection surface 152 that reflects light that is incident at a specific angle or greater. The light that has entered total reflection prism 151 from the relay lens system made up of convex lenses 143, 144, and 145 is totally reflected when it is incident at an angle greater than the total reflection angle, and is then guided to DMD 571.

[0152] DMD 571 is composed of a plurality of micromirrors corresponding to pixels, and changes the direction of travel of light by changing the tilt direction of the micromirrors in response to a video signal in a video circuit (not shown). The light, whose direction of travel has been changed in response to the video signal, passes through total reflection surface 152 and exits total reflection prism 151. The light then enters projection lens 191 and is then projected onto a screen (not shown).

[0153] As mentioned above, the combination of the wavelength conversion particle peripheral configuration, phosphor wheel, light source device, and projection-type image display device is not limited to the above configuration example, and may be changed as appropriate depending on the application, function, required specifications, etc. of the device.

[0154] [Light-emitting region of wavelength-converting particles] Fig. 5 is a diagram illustrating the light-emitting region of wavelength-converting particles 4. Here, the description focuses on the multiple wavelength-converting particles 4 that make up the wavelength-converting layer 3. The wavelength-converting particles 4 have an ellipsoidal shape and have a major axis and a minor axis. Here, for convenience, the length of the major axis of the wavelength-converting particles 4 is indicated by Ll, and the length of the minor axis is indicated by Ls (Ll > Ls).

[0155] Note that if the shape of the wavelength conversion particles 4 is other than an ellipsoid, the shape of the wavelength conversion particles 4 may be treated in the same manner by defining a first length and a second length that is shorter than the first length. In this case, the direction of the first length and the direction of the second length are considered to be perpendicular to each other.

[0156] First, in wavelength conversion particles, fluorescence is emitted due to wavelength conversion in the area through which the excitation light passes. For example, as shown in the center column of Figure 5, wavelength conversion occurs in the area through which the excitation light passes. Furthermore, in wavelength conversion particles, the energy that cannot be fully converted during wavelength conversion is converted into heat, generating heat in the area through which the excitation light passes.

[0157] The fluorescence wavelength-converted by the wavelength-converting particles is completely diffused, and the light travels in all directions around it. Here, because the wavelength-converting particles have a higher refractive index than their surroundings, light at angles greater than the total reflection angle is reflected at the interface between the particles and travels inside the wavelength-converting particles. Then, light that has become smaller than the total reflection angle is emitted from the wavelength-converting particles.

[0158] On the other hand, heat generated in the wavelength conversion particles is mainly transferred from the wavelength conversion layer to the substrate side by thermal conduction. In heat transfer by thermal conduction, heat is transferred more easily through a substance with a lower thermal resistance value. Therefore, when the same amount of heat is generated in substances with different thermal resistance values, the substance with the lower thermal resistance value will have a lower temperature. When the substrate is placed below the direction of propagation of the excitation light as shown in Figure 5, heat transfer by thermal conduction mainly occurs toward the lower substrate side.

[0159] The upper part of Figure 5 shows an example in which the wavelength conversion particles 4 are stacked with their minor axes aligned along the height direction (Z axis) relative to the horizontal direction (X-Y plane). In this configuration, when excitation light is incident from above, as shown in the center of the upper part, wavelength-converted fluorescence and heat loss are generated at the point where the excitation light passes, as shown in the right part of the upper part. The fluorescence is completely diffused as described above, and is emitted when its angle of total reflection becomes smaller as a result of traveling as shown in the right part of the upper part. Meanwhile, heat is conducted from the area where the excitation light passes to the surrounding area.

[0160] The middle section of Figure 5 shows an example in which the long axes of the wavelength conversion particles 4 are arranged along the height direction (Z axis) with respect to the horizontal direction (X-Y plane). In this configuration, when excitation light is incident from above as shown in the center of the middle section, wavelength-converted fluorescence and heat loss are generated at the point where the excitation light passes, as shown in the center of the middle section. The fluorescence is completely diffused as described above, and is emitted when its angle of total reflection becomes smaller as a result of traveling as shown on the right of the middle section. Meanwhile, heat is conducted from the area where the excitation light passes to the surrounding area.

[0161] The bottom row of Figure 5 shows an example of a wavelength conversion layer formed by stacking spherical wavelength conversion particles 4a. In this configuration, when excitation light is incident from above as shown in the center of the bottom row, wavelength-converted fluorescence and heat loss are generated at the location where the excitation light passes, as shown in the center of the bottom row. The fluorescence is completely diffused as described above, and is emitted when the angle of total reflection becomes smaller as a result of traveling as shown on the right side of the bottom row. Meanwhile, heat is conducted from the area where the excitation light passes to the surrounding area.

[0162] According to the above-mentioned principle, the configuration in the upper part of FIG. 5 has the largest light-emitting area, and the configuration in the lower part of FIG. 5 has the smallest light-emitting area.

[0163] In addition, the interfaces of wavelength-converting particles and the binders constituting the wavelength-converting layer generally have higher thermal resistance than the wavelength-converting particles. Therefore, to improve heat dissipation efficiency, it is preferable to suppress the presence of the interfaces of wavelength-converting particles and the binders constituting the wavelength-converting layer. Assuming that heat transfer occurs toward the substrate located at the bottom of the drawing as described above, comparing the configurations in the upper row, middle row (corresponding to the configuration example of the present disclosure), and lower row of Figure 5, the configuration in the middle row has the lowest thermal resistance. In other words, in the configuration example of the present disclosure, the number of interfaces and the presence of binders on the heat transfer path can be reduced, thereby making it possible to reduce the thermal resistance of the wavelength-converting layer.

[0164] In the present disclosure, wavelength conversion particles are arranged to improve the wavelength conversion efficiency of the wavelength conversion layer, thereby suppressing heat generation. Furthermore, by reducing the etendue of the light-emitting region in the wavelength conversion layer, the utilization efficiency of the optical system downstream of the wavelength conversion layer is improved. Note that etendue is the product of the volume of the wavelength conversion layer (i.e., wavelength conversion particles), which is the light-emitting portion, and the emitted light (i.e., the solid angle). Because the solid angle of the fluorescence from the wavelength conversion particles is completely diffused, the utilization efficiency is improved by reducing the emission size of the wavelength conversion layer.

[0165] Furthermore, in the present disclosure, instead of a layer structure of wavelength-converting particles 4a in the wavelength-converting layer as shown in the lower part of Fig. 5, a single layer of wavelength-converting particles 4 is formed. This reduces the number of interfaces and the presence of binders on the heat conduction path, thereby reducing the thermal resistance value of the wavelength-converting layer. As a result, it is possible to improve heat dissipation efficiency. This effect can be obtained not only when only one wavelength-converting particle 4 is stacked throughout the entire wavelength-converting layer, but also as long as the wavelength-converting layer includes a region where only one wavelength-converting particle 4 is stacked.

[0166] As described above, a wavelength conversion device (e.g., 10) according to this embodiment includes a substrate (e.g., 1, 8, 11, 18), an adhesive layer (e.g., 2, 12) provided on the substrate, and a wavelength conversion layer (e.g., 3) provided on the adhesive layer and including wavelength conversion particles (e.g., 4). The wavelength conversion particles have a first length (e.g., Ll) along a first direction and a second length (e.g., Ls) along a second direction perpendicular to the first direction that is shorter than the first length. The wavelength conversion particles are arranged in the wavelength conversion layer so that the first direction is perpendicular to the surface of the substrate. This configuration makes it possible to improve the efficiency performance of the wavelength conversion device. In particular, it is possible to emit light by the wavelength conversion particles within a range corresponding to the irradiation spot of the excitation light, thereby improving the luminous efficiency. Furthermore, improving the luminous efficiency can suppress unnecessary heat generation and temperature rise.

[0167] In the wavelength conversion device according to the present embodiment, the wavelength conversion particles have an ellipsoidal shape, the first length is the length of the major axis, and the second length is the length of the minor axis. This configuration makes it possible to configure a wavelength conversion device using a wavelength conversion layer that includes ellipsoidal wavelength conversion particles.

[0168] In addition, in the wavelength conversion device according to this embodiment, the wavelength conversion layer has one wavelength conversion particle stacked in a direction perpendicular to the surface of the substrate. This configuration reduces the number of interfaces and the presence of binders on the thermal conduction path of heat generated by the wavelength conversion particles, thereby reducing the thermal resistance of the wavelength conversion layer. As a result, the heat dissipation efficiency can be improved. Furthermore, the structure of the wavelength conversion layer can be simplified, which can improve, for example, the strength.

[0169] In the wavelength conversion device according to the present embodiment, the adhesive layer (e.g., 2) contains a material that reflects light. With this configuration, the wavelength conversion device can be configured using an adhesive layer that integrates a reflective function and an adhesive function, and the thickness of the wavelength conversion device can be reduced.

[0170] In the wavelength conversion device according to the present embodiment, the adhesive layer is composed of a first layer (e.g., 6) for reflecting light and a second layer (e.g., 7) having higher thermal conductivity than the first layer. With this configuration, the layer with the reflection function and the layer with the heat dissipation function are separately constructed, thereby making it possible to improve the performance of each function.

[0171] Furthermore, a light source device (e.g., 100) according to this embodiment includes the above-described wavelength conversion device (e.g., 10). With this configuration, it is possible to provide a light source device with improved efficiency performance. In particular, it is possible to provide an optical device with improved light utilization efficiency.

[0172] Furthermore, a projection-type image display device (e.g., 200) according to this embodiment includes the above-described light source device (e.g., 100). This configuration makes it possible to provide a projection-type image display device with improved efficiency. In particular, it makes it possible to provide a projection-type image display device with improved light utilization efficiency.

[0173] <Other Embodiments> In the above embodiment, the wavelength conversion device has been described as an example of a component of a projection-type image display device such as a projector. However, the use of the wavelength conversion device is not limited to this, and the wavelength conversion device may be used in other types of devices as long as it is used in devices with similar problems.

[0174] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to these examples. It is clear to those skilled in the art that various modifications, alterations, substitutions, additions, deletions, and equivalents may be made within the scope of the claims, and it is understood that these also fall within the technical scope of the present disclosure. Furthermore, the components of the various embodiments described above may be combined in any manner without departing from the spirit of the invention.

[0175] (Additional Notes) The above embodiments disclose the following techniques. (Technology 1) A wavelength conversion device comprising: a substrate; an adhesive layer provided on the substrate; and a wavelength conversion layer provided on the adhesive layer and containing wavelength conversion particles, wherein the wavelength conversion particles have a first length along a first direction and a second length along a second direction perpendicular to the first direction that is shorter than the first length, and the wavelength conversion particles are arranged in the wavelength conversion layer so that the first direction is perpendicular to the surface of the substrate. This configuration makes it possible to improve the luminous efficiency and heat dissipation efficiency of the wavelength conversion device. In particular, it is possible to emit light by the wavelength conversion particles within a range corresponding to the irradiation spot of the excitation light, thereby improving the luminous efficiency. Furthermore, improving the luminous efficiency can suppress unnecessary heat generation and temperature rise.

[0176] (Technology 2) The wavelength conversion device according to Technology 1, wherein the wavelength conversion particles have an ellipsoidal shape, the first length is a length of a major axis, and the second length is a length of a minor axis. This configuration makes it possible to configure a wavelength conversion device using a wavelength conversion layer that includes ellipsoidal wavelength conversion particles.

[0177] (Technology 3) The wavelength conversion device according to Technology 1 or Technology 2, wherein the wavelength conversion layer includes a region where only one wavelength conversion particle is stacked in a direction perpendicular to the surface of the substrate. This configuration reduces the number of interfaces and the presence of binders on the thermal conduction path of heat generated by the wavelength conversion particles, thereby reducing the thermal resistance of the wavelength conversion layer. As a result, it is possible to improve heat dissipation efficiency. Furthermore, the structure of the wavelength conversion layer can be simplified, thereby improving, for example, its strength.

[0178] (Technology 4) The wavelength conversion device according to any one of Technology 1 to Technology 3, wherein the adhesive layer includes a material that reflects light. According to this configuration, the wavelength conversion device can be configured using an adhesive layer that integrates a reflective function and an adhesive function, and the thickness of the wavelength conversion device can be reduced.

[0179] (Technology 5) The wavelength conversion device according to any one of Technology 1 to Technology 3, wherein the adhesive layer is composed of a first layer for reflecting light and a second layer having higher thermal conductivity than the first layer. According to this configuration, by separately configuring the layer with the reflective function and the layer with the heat dissipation function, it is possible to improve the performance of each function.

[0180] (Technology 6) A light source device including the wavelength conversion device according to any one of Technology 1 to Technology 5. According to this configuration, it is possible to provide a light source device with improved efficiency performance. In particular, it is possible to provide an optical device with improved light utilization efficiency.

[0181] (Technology 7) A projection-type image display device having the light source device according to Technology 6. This configuration makes it possible to provide a projection-type image display device with improved efficiency, particularly with improved light utilization efficiency.

[0182] The present disclosure is useful as a wavelength conversion device, a light source device, and a projection-type image display device.

[0183] DESCRIPTION OF SYMBOLS 1, 11, 18 Substrate 2, 12 Adhesive layer 3, 13 to 15 Wavelength conversion layer 4, 4a Wavelength conversion particles 5 Binder 6, 16 Reflective layer 7 Adhesive layer 8 Transmittance substrate 10 (10a to 10f) Phosphor wheel 17 Opening 19 Motor 100 (100a to 100i) Light source device 101, 111 Laser light source 102, 112 Collimator lens 103, 113, 121, 122, 141, 143 to 145, 246, 250, 252, 254 to 256, 411, 412, 811, 812, 814, 816, 818, 911 to 913 Convex lens 104, 114 Diffuser 105, 115 Concave lens 106, 208 Retardation plate 107, 207, 247, 249, 507, 607, 707, 807 Dichroic mirror 131, 231, 331, 431, 531, 631, 731, 831, 931 Phosphor wheel 142 Rod integrator 151 Total reflection prism 161 Color prism 171 DMD (Digital Mirror Device) 191 Projection lens 200 (200a to 200c) Projection type image display device 241, 243, 248, 251, 253, 813, 815, 817 Total reflection mirror 242, 244 Fly's eye lens 245 Polarization conversion array 261 to 263, 267 to 269 Polarizing plate 266 LCD (Liquid Crystal Display) 270 Dichroic prism 581 Color wheel 608 Retardation plate

Claims

1. A wavelength conversion device comprising: a substrate; an adhesive layer provided on the substrate; and a wavelength conversion layer provided on the adhesive layer and comprising wavelength conversion particles, wherein the wavelength conversion particles have a first length along a first direction and a second length along a second direction perpendicular to the first direction that is shorter than the first length, and the wavelength conversion particles are arranged in the wavelength conversion layer so that the first direction is perpendicular to the surface of the substrate.

2. The wavelength converting device of claim 1, wherein the wavelength converting particles are ellipsoidal in shape, the first length is the length of a major axis, and the second length is the length of a minor axis.

3. The wavelength conversion device according to claim 1, wherein the wavelength conversion layer includes an area where only one wavelength conversion particle is stacked in a direction perpendicular to the surface of the substrate.

4. The wavelength conversion device according to claim 1, wherein the adhesive layer includes a material that reflects light.

5. The wavelength conversion device according to claim 1, wherein the adhesive layer is composed of a first layer for reflecting light and a second layer having higher thermal conductivity than the first layer.

6. The wavelength-converting device of claim 1, wherein at least two of the wavelength-converting particles are arranged adjacent to each other in the second direction.

7. A light source device comprising a wavelength conversion device according to any one of claims 1 to 6.

8. A projection type image display device having the light source device according to claim 7.

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