Phosphor wheel, light source device, and projection image display device

Abstract

To improve cooling performance at a low cost. [Solution] The phosphor wheel of the present disclosure comprises a first substrate made of a metallic material having a first main surface and a second main surface opposite to the first main surface; a phosphor ring provided on the first main surface of the first substrate; a second substrate made of a metallic material having a third main surface disposed on the second main surface of the first substrate and a fourth main surface opposite to the third main surface; and a plurality of heat dissipation fins formed on the fourth main surface of the second substrate, wherein the second main surface of the first substrate and the third main surface of the second substrate are joined by brazing.

Description

Technical Field

[0001] The present disclosure relates to a phosphor wheel, a light source device, and a projection type video display device.

Background Art

[0002] Patent Document 1 discloses a phosphor wheel that effectively cools a phosphor layer. The phosphor wheel described in Patent Document 1 includes a substrate having a first main surface, a second main surface, and an opening, a phosphor layer provided on the first main surface, and fins provided on the second main surface. The fins are located closer to the center of the substrate than the phosphor layer, and the opening is located between the phosphor layer and the fins in a direction from the center of the substrate toward the outer periphery of the substrate.

[0003] Patent Document 2 discloses a light source device provided with a phosphor device. The light source device described in Patent Document 2 includes an excitation light source that emits excitation light in a predetermined wavelength band, an inorganic binder phosphor layer that emits fluorescence upon receiving the excitation light, and a thin film that reflects light of a desired wavelength formed on the inorganic binder phosphor layer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Documents 1 and 2, there is still room for improvement in terms of improving the cooling performance at a low cost.

[0006] An object of the present disclosure is to provide a phosphor wheel, a light source device, and a projection type video display device capable of improving the cooling performance at a low cost. [Means for solving the problem]

[0007] A phosphor wheel according to one aspect of the present disclosure comprises a first substrate made of a metallic material having a first main surface and a second main surface opposite to the first main surface; a phosphor ring provided on the first main surface of the first substrate; a second substrate made of a metallic material having a third main surface disposed on the second main surface of the first substrate and a fourth main surface opposite to the third main surface; and a plurality of heat dissipation fins formed on the fourth main surface of the second substrate, wherein the second main surface of the first substrate and the third main surface of the second substrate are joined by brazing.

[0008] A light source device according to one aspect of the present disclosure comprises a phosphor wheel according to the said aspect.

[0009] A projection-type image display device according to one aspect of the present disclosure comprises a light source device according to the aforementioned aspect. [Effects of the Invention]

[0010] This disclosure provides a phosphor wheel, a light source device, and a projection-type image display device that can improve cooling performance at low cost. [Brief explanation of the drawing]

[0011] [Figure 1] Schematic diagram of an example of a projection-type video display device according to Embodiment 1 [Figure 2A] Schematic diagram of an example laser diode unit [Figure 2B] Schematic diagram of an example laser diode unit [Figure 3] A schematic diagram showing an example of a partial reflection mirror. [Figure 4] Schematic diagram illustrating the optical path of the emitted light from a laser diode unit. [Figure 5A] Schematic diagram of the phosphor wheel as seen from the first substrate side. [Figure 5B] Schematic diagram of the phosphor wheel viewed from the second substrate side. [Figure 6] Schematic partial cross-section of a phosphor wheel [Figure 7]Schematic perspective view of the phosphor wheel as seen from the second substrate side [Figure 8] Schematic diagram showing the configuration of the phosphor wheel on the second substrate side [Figure 9] Schematic perspective view of the phosphor wheel of the modified example as seen from the second substrate side [Figure 10] Schematic perspective view of the phosphor wheel of the modified example as seen from the second substrate side [Figure 11A] Schematic diagram for explaining the attachment of the first substrate and the motor [Figure 11B] Schematic diagram for explaining the attachment of the first substrate and the motor

Mode for Carrying Out the Invention

[0012] (Background Leading to the Present Disclosure) The light source of a projection type video display device is shifting from a conventional discharge lamp to an LED or a laser in terms of lifespan and environmental issues. In the case of an LED, the emission angle is large, and the spread of light becomes larger as the size of the light emitting part increases. Therefore, for a projection type video display device, there are limitations on the size of the light emitting part and the spread angle of light, and it is not possible to obtain a high light output with an LED. On the other hand, a laser has a small light spread, and it is possible to increase the output by combining a number of lasers. Therefore, it has become mainstream to use a laser as the light source of a projection type video display device. Also, when using a high-output blue wavelength laser as the light source, in order to obtain white light, a phosphor that emits yellow light with the laser as excitation light is used.

[0013] In the case of a phosphor, heat is generated by the energy of the excitation light. Due to this heat, the temperature of the phosphor rises, and temperature quenching occurs where the fluorescence efficiency decreases. To solve this, an annular phosphor is provided on a metal disk, and the temperature is reduced by rotating the metal disk.

[0014] On the one hand, in order to achieve further higher brightness, an increase in the output power of the laser is required. Along with this, a structure for improving the cooling performance for cooling the phosphor is being studied. For example, attempts are being made to improve the cooling performance by introducing cooling fins into a metal disk provided with a phosphor, or by integrating cutting member fins with the metal disk.

[0015] In the phosphor wheel described in Patent Document 1, a phosphor layer is provided on the first main surface of a substrate, and a fan member is attached to the second main surface of the substrate. The fan member is composed of a separate member from the substrate and has a plurality of fins. The fan member is rotated integrally with the substrate by a motor, and each of the plurality of fins blows air outward (in the centrifugal direction) with respect to the fin according to the rotation of the substrate. The air generated outward by the plurality of fins flows toward the phosphor layer through a plurality of openings penetrating the first main surface and the second main surface of the substrate, and cools the phosphor layer. However, the phosphor wheel described in Patent Document 1 still has room for improvement in terms of improving the cooling performance.

[0016] In the light source device described in Patent Document 2, a radiator, a heat sink, etc. are used as cooling means for radiating the heat of the phosphor layer. However, in the light source device described in Patent Document 2, since the weight increases by attaching a radiator or a heat sink, a motor having sufficient driving force is required. For this reason, problems such as an increase in cost associated with the enlargement of components such as a motor and / or the generation of noise occur. Also, when a heat conductive material such as grease is applied between the substrate and the heat sink, the grease softens or scatters due to use at high temperatures or high-speed rotation, and reliability cannot be guaranteed.

[0017] Therefore, in order to solve these problems, the present inventors have studied a phosphor wheel that can improve the cooling performance at a low cost. Then, the present inventors have found a phosphor wheel in which a first substrate provided with a phosphor ring and a second substrate provided with a plurality of radiation fins are joined by brazing, and have arrived at the present disclosure.

[0018] The embodiments will be described in detail below, with reference to the drawings as appropriate. However, unnecessarily detailed explanations may be omitted. For example, detailed explanations of already well-known matters and redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding for those skilled in the art.

[0019] The attached drawings and the following description are provided to enable a person skilled in the art to fully understand this disclosure, and are not intended to limit the subject matter described in the claims.

[0020] (Embodiment 1) [1-1. Configuration of a projection-type image display device] Figure 1 is a schematic diagram showing an example of a projection-type image display device 100 according to Embodiment 1. As shown in Figure 1, the projection-type image display device 100 comprises a light source device 200 and an illumination optical system 300.

[0021] In this embodiment, the light source device 200 includes laser diode units 101a, 101b, a partial reflection mirror 102, lenses 103, 108, 110, 112, 113, mirrors 104, 109, 114, diffusers 105, 115, condenser lenses 106, 116, 117, a dichroic mirror 107, a phosphor wheel 118, and a motor 119. The illumination optical system 300 includes a rod integrator 111, relay lenses 120, 121, a mirror 122, a field lens 123, a total reflection prism 124, a color prism unit 129, digital micromirror devices (DMDs) 135R, 135G, 135B, and a projection lens 136. Note that the configurations of the light source device 200 and illumination optical system 300 shown herein are illustrative and not limited to these elements.

[0022] First, let me explain the light source device 200.

[0023] In the light source device 200, laser diode units 101a and 101b are used as light sources. Figures 2A and 2B are schematic diagrams of examples of laser diode units 101a and 101b, respectively. As shown in Figures 2A and 2B, the device includes multiple laser light sources 10A and 10B. Each of the multiple laser light sources 10A and 10B includes multiple blue laser diodes (not shown) and multiple collimating lenses 11 arranged on the emission side of the multiple blue laser diodes. The multiple collimating lenses 11 are arranged on the optical axis of the light emitted by the multiple blue laser diodes. In this embodiment, three laser light sources 10A are arranged side by side in the laser diode unit 101a, and three laser light sources 10B are arranged side by side in the laser diode unit 101b.

[0024] The laser diode units 101a and 101b emit blue light with a central wavelength of, for example, 456 nm. The light emitted by the laser diode units 101a and 101b is incident on the partial reflection mirror 102. The partial reflection mirror 102 is a mirror that partially reflects a certain amount of blue wavelength light.

[0025] Figure 3 is a schematic diagram of an example of a partial reflection mirror 102. As shown in Figure 3, the partial reflection mirror 102 has a plurality of reflective parts 12 that reflect blue light and a plurality of transmissive parts 13 that transmit blue light. Each of the plurality of reflective parts 12 and the plurality of transmissive parts 13 has a rectangular shape with a longitudinal direction. The plurality of reflective parts 12 and the plurality of transmissive parts 13 are arranged alternately. Each of the plurality of reflective parts 12 has the characteristic of reflecting a certain amount of blue wavelength. That is, in the plurality of reflective parts 12, a portion of the incident blue light is reflected and a portion of the incident blue light is transmitted.

[0026] The blue light emitted from the laser diode units 101a and 101b is incident on the partial reflection mirror 102. The partial reflection mirror 102 selectively reflects and transmits the blue light.

[0027] Figure 4 is a schematic diagram illustrating the optical path of the light emitted from laser diode units 101a and 101b. As shown in Figure 4, the light emitted from laser diode unit 101a travels in the +X direction and is incident on multiple reflective sections 12 of the partial reflection mirror 102. At the multiple reflective sections 12, a portion of the light emitted from laser diode unit 101a is reflected in the +Y direction, and the remaining light is transmitted in the +X direction. The light emitted from laser diode unit 101b travels in the +Y direction and is incident on multiple transmissive sections 13 of the partial reflection mirror 102. At the multiple transmissive sections 13, all the light emitted from laser diode unit 101b is transmitted in the +Y direction. In this way, a large amount of light is guided in the +Y direction.

[0028] Returning to Figure 1, in the partial reflection mirror 102, the blue light emitted in the +X direction is focused by the lens 103, reflected by the mirror 104, and then focused by the diffuser plate 105. The blue light focused by the diffuser plate 105 is incident on the condenser lens 106, becoming approximately parallel light and then incident on the dichroic mirror 107. The dichroic mirror 107 has the characteristic of transmitting blue light and reflecting other colored light. The blue light that has passed through the dichroic mirror 107 passes through the lens 108, mirror 109 and lens 110, and is focused on the incident surface of the rod integrator 111 of the illumination optical system 300.

[0029] In the partial reflection mirror 102, blue light emitted in the +Y direction is focused by lenses 112 and 113 that form an afocal system with the mirror 114 in between, and incident on the diffuser plate 115. After being diffused by the diffuser plate 115, the blue light passes through the dichroic mirror 107. The blue light that has passed through the dichroic mirror 107 passes through condenser lenses 116 and 117 and incident on the phosphor wheel 118.

[0030] The phosphor wheel 118 is constructed by providing a phosphor layer. The phosphor wheel 118 has a motor 119. The phosphor wheel 118 rotates by the motor 119. The phosphor layer is formed by coating, for example, a YAG phosphor that is excited by blue light and emits yellow light containing green and red wavelength components. Light substantially imaged by the phosphor layer of the phosphor wheel 118 is reflected as yellow light. The detailed configuration of the phosphor wheel 118 will be described later.

[0031] The yellow light (fluorescent light) reflected by the phosphor wheel 118 passes through the condenser lenses 117 and 116 and enters the dichroic mirror 107. The yellow light is reflected by the dichroic mirror 107 and, like the blue light, passes through lens 108, mirror 109, and lens 110, and is focused onto the incident surface of the rod integrator 111 of the illumination optical system 300.

[0032] In the light source device 200, when blue light and yellow light are focused onto the incident surface of the rod integrator 111, the blue light and yellow light (fluorescent light) are superimposed. This creates white light.

[0033] Next, the illumination optical system 300 will be described.

[0034] In the illumination optical system 300, the rod integrator 111 is made of a transparent material such as glass. The rod integrator 111 generates light with a uniform intensity distribution by reflecting the incident light multiple times inside. The rod integrator 111 may be a solid rod, or it may be a hollow rod whose inner wall is made of a mirror surface.

[0035] Light (white light) emitted from the rod integrator 111 passes through relay lenses 120 and 121, is reflected by the folding mirror 122, then passes through the field lens 123, and enters the total internal reflection prism 124. The total internal reflection prism 124 has a first prism 125 and a second prism 126. A gap is provided between the first prism 125 and the second prism 126. The first prism 125 and the second prism 126 have, for example, a roughly triangular prism shape. The total internal reflection prism 124 causes the incident white light to undergo total internal reflection and emits it toward the color prism unit 129. Specifically, light incident on the total internal reflection prism 124 undergoes total internal reflection at the first surface 127, then passes through the second surface 128 and enters the color prism unit 129.

[0036] The color prism unit 129 comprises a first prism 131 having a first dichroic mirror surface 130 with the property of reflecting blue light, a second prism 133 having a second dichroic mirror surface 132 with the property of reflecting red light, and a third prism 134. The first prism 131, the second prism 133, and the third prism 134 are bonded together. Image forming elements (DMDs: Digital Micromirror Devices) 135R, 135G, and 135B are arranged on the end faces of each prism. The DMDs 135R, 135G, and 135B are composed of multiple micro-mirrors arranged two-dimensionally, and their tilt direction is controlled in two directions according to an external video signal. When the signal is ON, the reflected light returns to the color prism unit 129 at an incident angle of 0°, and when the signal is OFF, it is incident again at a larger angle. The DMD135B is for blue light modulation, the DMD135R is for red light modulation, and the DMD135G is for green light modulation.

[0037] Each of the minute mirrors in the DMD135R, 135G, and 135B essentially corresponds to one pixel. Based on various control signals, the DMD135R, 135G, and 135B change the angle of each minute mirror, thereby switching whether or not the light reflected by the DMD135R, 135G, and 135B is directed towards the projection lens 136. Specifically, the light in white display mode at each pixel in the DMD135R, 135G, and 135B returns to the color prism unit 129, passes through the first prism 125 and the second prism 126 of the total internal reflection prism 124, enters the projection lens 136, and is projected onto the screen. This is how color display is achieved. Details of the light path of the OFF light in the DMD135R, 135G, and 135B are omitted here, but since it is controlled so that it does not enter the projection lens 136, it is displayed as black on the screen.

[0038] [1-2. Configuration of the phosphor wheel] Figure 5A is a schematic diagram of the phosphor wheel 118 viewed from the first substrate 14 side, and Figure 5B is a schematic diagram of the phosphor wheel 118 viewed from the second substrate 16 side. Figure 6 is a schematic partial cross-sectional view of the phosphor wheel 118. As shown in Figures 5A-6, the phosphor wheel 118 comprises a first substrate 14, a phosphor ring 15, a second substrate 16, and a plurality of heat dissipation fins 17. In the phosphor wheel 118, the phosphor ring 15 is provided on the first substrate 14, and the plurality of heat dissipation fins 17 are provided on the second substrate 16. The first substrate 14 and the second substrate 16 are joined by brazing.

[0039] Furthermore, the phosphor wheel 118 is equipped with a motor 119 and is rotated by the motor 119. When a phosphor receives excitation light, it emits fluorescence, but in the process, approximately half of the energy is converted into heat. To suppress burnout due to rapid heat generation, the phosphor wheel 118 is rotated, which suppresses the temperature rise even when receiving concentrated excitation light, enabling efficient conversion to fluorescence (yellow light in this example) over a long period of time.

[0040] The first substrate 14 has a first main surface PS1 and a second main surface PS2 opposite to the first main surface PS1, and is made of a metallic material. The first substrate 14 is a circular metal disc with an outer diameter D1 when viewed from the first main surface PS1 side. "When viewed from the first main surface PS1 side" means looking in the thickness direction of the first substrate 14, that is, in the direction from the first main surface PS1 to the second main surface PS2. Specifically, the metallic material constituting the first substrate 14 is a metallic material with excellent heat dissipation properties. For example, aluminum material (such as pure aluminum) can be used as the metallic material constituting the first substrate 14.

[0041] Viewed from the first main surface PS1 side, a first hole 15a is provided in the center of the first substrate 14. The first hole 15a is a circular hole with a diameter D2 when viewed from the first main surface PS1 side. The center of the first hole 15a coincides with the center of the first substrate 14. A motor 119 is mounted in the first hole 15a. The motor 119 has a mounting portion 18. The mounting portion 18 has a cylindrical shape and also functions as a rotation axis. The motor 119 is mounted to the first substrate 14 by inserting the mounting portion 18 into the first hole 15a.

[0042] Furthermore, an annular fixing flange 19 is provided on the first main surface PS1 of the first substrate 14. The fixing flange 19 and the motor 119 are fixed together, for example, by screws. Specifically, the motor 119 has a motor flange 21 located on the second main surface PS2 of the first substrate 14. The first substrate 14 is sandwiched between the fixing flange 19 and the motor flange 21. Through holes are provided in the fixing flange 19 and the first substrate 14, and screw holes are provided in the motor flange 21. Fixing screws pass through the through holes in the fixing flange 19 and the first substrate 14 and are screwed into the screw holes in the motor flange 21. In this way, the motor 119 is attached to the first substrate 14.

[0043] The outer circumference of the mounting portion 18 of the motor 119, the inner circumference of the fixing flange 19, and the inner circumference 22 of the first substrate 14 have small mechanical tolerances and are in contact with almost no gaps. The inner circumference 22 of the first substrate 14 refers to the inner wall that defines the first hole 15a. In other words, the outer diameter of the mounting portion 18, the inner diameter of the fixing flange 19, and the inner diameter of the first substrate 14 (the diameter D2 of the first hole 15a) have fit dimensions with small mechanical tolerances.

[0044] The phosphor ring 15 is provided on the first main surface PS1 of the first substrate 14. The phosphor ring 15 is made of a YAG phosphor that, for example, is excited by blue light and emits yellow light containing green and red wavelength components. For example, the phosphor ring 15 is fixed to the first substrate 14 with an adhesive containing a material having reflective properties (for example, titanium oxide). When the first substrate 14 is viewed from the first main surface PS1 side, the phosphor ring 15 has an annular shape. When viewed from the first main surface PS1 side, the center of the phosphor ring 15 and the center of the first substrate 14 are approximately coincident. When viewed from the first main surface PS1 side, the phosphor ring 15 is formed on the outer periphery of the first substrate 14 rather than the center. Specifically, the phosphor ring 15 is formed along the outer periphery of the first substrate 14. In this embodiment, the phosphor ring 15 is formed slightly inward from the outer periphery of the first substrate 14.

[0045] The second substrate 16 has a third main surface PS3 and a fourth main surface PS4 opposite to the third main surface PS3, and is made of a metallic material. The second substrate 16 is placed on top of the first substrate 14. The third main surface PS3 is located on the second main surface PS2 of the first substrate 14. The second substrate 16 is a metal plate-like member having a circular shape with an outer diameter D3 when viewed from the fourth main surface PS4 side. "When viewed from the fourth main surface PS4 side" means viewing in the thickness direction of the second substrate 16, that is, in the direction from the fourth main surface PS4 toward the third main surface PS3. Specifically, the second substrate 16 is a disc made of a metallic material with excellent heat dissipation properties. The outer diameter D3 of the second substrate 16 is equal to the outer diameter D1 of the first substrate 14.

[0046] Preferably, the thermal expansion coefficient of the metal material constituting the second substrate 16 is equal to that of the metal material constituting the first substrate 14. More preferably, the metal material constituting the second substrate 16 is the same as the metal material constituting the first substrate 14. This configuration facilitates the transfer of heat from the first substrate 14 to the second substrate 16.

[0047] Viewed from the fourth main surface PS4 side, a second hole 16a is provided in the center of the second substrate 16. The second hole 16a is a circular hole with a diameter D4 when viewed from the fourth main surface PS4 side. The center of the second hole 16a coincides with the center of the second substrate 16. The diameter D4 of the second hole 16a is larger than the diameter D2 of the first hole 15a. Also, when viewed from the fourth main surface PS4 side, the diameter D4 of the second hole 16a is larger than the outer dimensions of the motor 119 on the third main surface PS3.

[0048] The diameter D4 of the second hole 16a is larger than the outer diameter of the motor flange 21 of the motor 119. As a result, the outer circumference 21a of the motor flange 21 and the inner circumference 23 of the second substrate 16 are separated, and the second substrate 16 does not come into contact with the motor 119. Since the motor 119 is connected to the first substrate 14 without coming into contact with the second substrate 16, the rotation of the motor 119 can be efficiently transmitted to the first substrate 14. In addition, if the brazing material 20 overflows from between the first substrate 14 and the second substrate 16 during brazing, the gap between the inner circumference 23 of the second substrate 16 and the outer circumference 21a of the motor flange 21 provides space for the overflowing brazing material 20 to flow into. This prevents the brazing material 20 from affecting the mounting of the motor 119.

[0049] Multiple heat dissipation fins 17 are formed on the fourth main surface PS4 of the second substrate 16. The multiple heat dissipation fins 17 are formed integrally with the second substrate 16 and are bent in a direction intersecting the fourth main surface PS4. Specifically, the multiple heat dissipation fins 17 are formed by cutting and bending the second substrate 16. Each of the multiple heat dissipation fins 17 is a plate-shaped member formed in a direction intersecting the fourth main surface PS4. In this embodiment, each of the multiple heat dissipation fins 17 is formed as a substantially rectangular plate-shaped member extending in a direction perpendicular to the fourth main surface PS4. Furthermore, the multiple heat dissipation fins 17 are arranged at equal intervals inside the outer circumference of the second substrate 16.

[0050] Multiple heat dissipation fins 17 are formed by cutting and bending the second substrate 16, and a rectangular opening 17a is provided adjacent to the multiple heat dissipation fins 17. The second main surface PS2 of the first substrate 14 is exposed through the opening 17a.

[0051] Multiple heat dissipation fins 17 generate airflow as the second substrate 16 rotates together with the first substrate 14 due to the rotation of the motor 119, thereby dissipating the heat generated in the phosphor ring 15. Specifically, the heat generated in the phosphor ring 15 is conducted to the second substrate 16 via the first substrate 14. The multiple heat dissipation fins 17 dissipate the heat generated in the phosphor ring 15 by dissipating the heat from the second substrate 16 with airflow.

[0052] Figure 7 is a schematic perspective view of the phosphor wheel 118 as seen from the second substrate 16 side. As shown in Figure 7, at least a portion of the multiple heat dissipation fins 17 are formed in a position that overlaps with the phosphor ring 15 when viewed from the fourth main surface PS4 side of the second substrate 16. Specifically, when viewed from the fourth main surface PS4 side, the multiple heat dissipation fins 17 are arranged in a ring shape along the outer circumference of the second substrate 16. This makes it easier to dissipate the heat generated from the phosphor ring 15. Specifically, the heat from the phosphor ring 15 is transferred to the multiple heat dissipation fins 17 at a high temperature, and the heat dissipation performance is improved by increasing the temperature difference with the coolant air.

[0053] Furthermore, when viewed from the fourth main surface PS4 side, the multiple openings 17a are formed in positions that overlap with the phosphor ring 15. As a result, the second main surface PS2 of the first substrate 14, opposite to the first main surface PS1 on which the phosphor ring 15 is located, is exposed through the multiple openings 17a. Heat generated by the phosphor ring 15 can be dissipated from the second main surface PS2 of the first substrate 14 exposed through the multiple openings 17a. This improves the heat dissipation performance compared to the area where the second substrate 16 is located.

[0054] The first substrate 14 and the second substrate 16 are joined by brazing. Specifically, the second main surface PS2 of the first substrate 14 and the third main surface PS3 of the second substrate 16 are joined by brazing. "Brazing" means joining multiple components by melting a brazing material with a lower melting point than the components to be joined and using it as an adhesive. Because the first substrate 14 and the second substrate 16 are brazed in this way, when the first substrate 14 is rotated by the motor 119, the second substrate 16 also rotates.

[0055] The second main surface PS2 of the first substrate 14 and the third main surface PS3 of the second substrate 16 are joined by a brazing material 20. The brazing material 20 is a metal material that has a lower melting point and higher thermal conductivity than the metal materials constituting the first substrate 14 and the second substrate 16. An AL-Si alloy can be used as the brazing material 20. The cladding material is specified as a brazing sheet in JIS Z 3263:2002, etc.

[0056] At least one of the first substrate 14 and the second substrate 16 may be made of clad material. The clad material has a plate-shaped base material made of a metal material and a brazing layer formed on at least one main surface of the base material. In this embodiment, the second substrate 16 is made of clad material. Specifically, the second substrate 16 has a third main surface PS3 and a fourth main surface PS4 opposite to the third main surface PS3, and has a base material made of a metal material and a brazing layer formed on the third main surface PS3.

[0057] By forming the second substrate 16 from a clad material with a thin brazing layer on the surface of the base material by rolling, the first substrate 14 and the second substrate 16 can be easily brazed by pressing them together and heating them in a furnace.

[0058] In this way, the first substrate 14 and the second substrate 16 are brazed together with brazing material 20. This makes it easier to conduct heat from the first substrate 14 to the second substrate 16 via the brazing material 20, thereby improving heat dissipation performance.

[0059] In this embodiment, the first substrate 14 has a circular shape when viewed from the first main surface PS1 side, and the second substrate 16 has a circular shape when viewed from the fourth main surface PS4 side, and the outer diameter D1 of the first substrate 14 and the outer diameter D3 of the second substrate 16 are equal. When brazing the first substrate 14 and the second substrate 16, the first substrate 14 and the second substrate 16 are positioned so that, when viewed from the first main surface PS1 side, the outer circumference of the first substrate 14 and the outer circumference of the second substrate 16 overlap. This makes it easy to center the first substrate 14 and the second substrate 16. Specifically, when brazing, it is easy to achieve a state where the center of the first substrate 14 and the center of the second substrate 16 overlap when viewed from the first main surface PS1 side of the first substrate 14.

[0060] Figure 8 is a schematic diagram showing the configuration of the phosphor wheel 118 on the second substrate 16 side. In Figure 8, for ease of explanation, the first annular flat portion 24 and the second annular flat portion 25 are shown with diagonal hatching. The second substrate 16 has the first annular flat portion 24 and the second annular flat portion 25.

[0061] The first annular flat portion 24 is formed inward from the plurality of heat dissipation fins 17 when viewed from the fourth main surface PS4 side. The first annular flat portion 24 has a continuous flat annular shape when viewed from the fourth main surface PS4 side. Here, "continuous" means that it is connected without interruption. When viewed from the fourth main surface PS4 side, the first annular flat portion 24 is formed inward from the innermost part of the plurality of heat dissipation fins 17 in the radial direction of the second substrate 16.

[0062] The second annular flat portion 25 is formed outside the plurality of heat dissipation fins when viewed from the fourth main surface PS4 side. When viewed from the fourth main surface PS4 side, the second annular flat portion 25 has a continuous flat annular shape and is formed along the outer circumference of the second substrate. When viewed from the fourth main surface PS4 side, the second annular flat portion 25 is formed outside the outermost portion of the plurality of heat dissipation fins 17 in the radial direction of the second substrate 16. When viewed from the fourth main surface PS4 side, the inner diameter of the second annular flat portion 25 is larger than the outer diameter of the first annular flat portion 24. The outer diameter of the second annular flat portion 25 is equal to the outer diameter of the second substrate 16.

[0063] Thus, the second substrate 16 has a first annular flat portion 24 and a second annular flat portion 25, and a plurality of heat dissipation fins 17 are arranged between the first annular flat portion 24 and the second annular flat portion 25. This increases the rigidity of the second substrate 16 and prevents the plurality of heat dissipation fins 17 from floating away from the second substrate 16.

[0064] [1-3. Effects] The phosphor wheel 118 of this disclosure comprises a first substrate 14, a phosphor ring 15, a second substrate 16, and a plurality of heat dissipation fins 17. The first substrate 14 has a first main surface PS1 and a second main surface PS2 opposite to the first main surface PS1, and is made of a metallic material. The phosphor ring 15 is provided on the first main surface PS1 of the first substrate 14. The second substrate 16 has a third main surface PS3 located on the second main surface PS2 of the first substrate 14, and a fourth main surface PS4 opposite to the third main surface PS3, and is made of a metallic material. The plurality of heat dissipation fins 17 are formed on the fourth main surface PS4 of the second substrate 16. The second main surface PS2 of the first substrate 14 and the third main surface PS3 of the second substrate 16 are joined by brazing.

[0065] This configuration allows for inexpensive improvement of cooling performance. Specifically, by joining the first substrate 14 and the second substrate 16 by brazing, the thermal conductivity between the first substrate 14 and the second substrate 16 can be improved. As a result, heat dissipation performance can be improved, thus improving cooling performance. Furthermore, brazing can be performed relatively easily and inexpensively.

[0066] The first substrate 14 has a circular shape when viewed from the first main surface PS1 side, and the second substrate 16 has a circular shape when viewed from the fourth main surface PS4 side, and the outer diameter D1 of the first substrate 14 and the outer diameter D3 of the second substrate 16 are equal. When viewed from the first main surface PS1 side of the first substrate 14, the outer circumference of the first substrate 14 and the outer circumference of the second substrate 16 overlap. With this configuration, positioning when brazing the first substrate 14 and the second substrate 16 becomes easier, and centering the first substrate 14 and the second substrate 16 becomes easier.

[0067] The phosphor wheel 118 further includes a motor 119 attached to the first substrate 14. Viewed from the first main surface PS1 side of the first substrate 14, a first hole 15a for mounting the motor is provided in the center of the first substrate 14. Viewed from the fourth main surface PS4 side of the second substrate 16, a second hole 16a, larger than the first hole 15a, is provided in the center of the second substrate 16. This configuration allows the motor 119 to be attached to the first substrate 14 without contacting the second substrate 16. This eliminates the influence of the brazing condition between the substrates on the attachment. By minimizing factors such as tilt between the motor and the phosphor, stable rotation without tilting or twisting is achieved. This maintains the positional relationship between the optical component and the phosphor, resulting in stable optical properties.

[0068] At least a portion of the multiple heat dissipation fins 17 are formed in a position that overlaps with the phosphor ring 15 when viewed from the fourth main surface PS4 side of the second substrate 16. This configuration shortens the heat transfer distance between the phosphor ring 15 and the multiple heat dissipation fins 17, thereby improving heat dissipation performance. This improves cooling performance.

[0069] The second substrate 16 has a first annular flat portion 24 and a second annular flat portion 25. The first annular flat portion 24 is formed inward from the plurality of heat dissipation fins 17 when viewed from the fourth main surface PS4 side. The second annular flat portion 25 is formed outward from the plurality of heat dissipation fins 17 when viewed from the fourth main surface PS4 side. The first annular flat portion 24 has a continuous flat annular shape. The second annular flat portion 25 has a continuous flat annular shape and is formed along the outer circumference of the second substrate 16. With this configuration, the rigidity of the second substrate 16 can be improved, and thus the lifting of the plurality of heat dissipation fins 17 can be suppressed.

[0070] Multiple heat dissipation fins 17 are formed integrally with the second substrate 16 and are bent in a direction intersecting the fourth main surface PS4. This configuration facilitates heat transfer from the second substrate 16 to the multiple heat dissipation fins 17, further improving heat dissipation performance.

[0071] At least one of the first substrate 14 and the second substrate 16 is made of clad material. The clad material has a plate-shaped base material made of a metal material and a brazing layer formed on the main surface of at least one of the base materials. This configuration makes brazing easy. For example, the first substrate 14 and the second substrate 16 can be pressed together and brazed by heating in a furnace. In addition, the second substrate 16 does not have the motor 119 attached or the phosphor ring 15 fixed to it like the first substrate 14, so there is less concern about performance impact. Therefore, it is preferable that the second substrate 16 is made of clad material.

[0072] The thermal expansion coefficients of the metal material constituting the first substrate 14 and the metal material constituting the second substrate 16 are equal. Preferably, the metal material constituting the first substrate 14 and the metal material constituting the second substrate 16 are the same. This configuration improves heat dissipation performance and further enhances cooling performance. Furthermore, even if the brazing temperature differs from the actual operating temperature, the occurrence of warping and cracking can be suppressed.

[0073] The light source device 200 includes the phosphor wheel 118 described above. With this configuration, the light source device 200 can achieve the same effects as the phosphor wheel 118 described above.

[0074] The projection-type image display device 100 includes a light source device 200 having the phosphor wheel 118 described above. With this configuration, the projection-type image display device 100 can also achieve the same effects as the phosphor wheel 118 described above.

[0075] In Embodiment 1, an example of the light source device 200 and illumination optical system 300 was described, but the invention is not limited thereto. For example, the light source device 200 and illumination optical system 300 may include additional and / or alternative elements, or some elements may be omitted.

[0076] In Embodiment 1, an example was described in which the phosphor ring 15 has an annular shape, but the invention is not limited to this. For example, the phosphor ring 15 may have a portion missing.

[0077] Embodiment 1 describes an example in which a plurality of heat dissipation fins 17 are formed by cutting and bending a second substrate 16, but the invention is not limited to this. For example, the plurality of heat dissipation fins 17 may be formed from a separate material from the second substrate 16. In this case, the second substrate 16 does not need to have an opening 17a.

[0078] In Embodiment 1, the shape and arrangement of the multiple heat dissipation fins 17 were described as an example shown in Figure 7, but the invention is not limited thereto. Figures 9 and 10 are schematic perspective views of a modified phosphor wheel 118 as seen from the second substrate 16 side. As shown in Figure 9, the length of the multiple heat dissipation fins 17 may be increased. Alternatively, as shown in Figure 10, the multiple heat dissipation fins 17 may be arranged further away from the center of the second substrate 16. In this case, the diameter of the second hole 16a may be further increased. This can reduce the rotational load.

[0079] In Embodiment 1, an example was described in which the motor 119 and the first substrate 14 are fixed to the fixing flange 19 and the motor flange 21 with screws, but the invention is not limited to this. For example, as shown in Figure 11A, the motor 119 may have a length in the thrust direction to increase the degree of freedom in setting the adjustment surface for balance adjustment. Alternatively, as shown in Figure 11B, the motor 119 may be directly fixed to the first substrate 14 without using a fixing flange.

[0080] In Embodiment 1, the projection-type image display device 100 is configured to use three DMDs, but it is not limited to this. The projection-type image display device 100 may also be configured to use three liquid crystal panels. Other configurations that require continuous fluorescent light are also well known to those in the industry as common technology. Furthermore, in a one-chip system that obtains color display by sequentially displaying colored light at high speed with a single DMD, it is necessary to obtain fluorescent light intermittently. Although details will be omitted here, if the wavelength of blue light is the same as the excitation light, a partial opening window may be provided in the phosphor portion of the phosphor wheel 118 to provide a separate optical path for blue light. In this case, the method can be directly applied as described in this disclosure by providing holes that penetrate the phosphor ring 15, the first substrate 14, and the second substrate 16. Also, if the opening is large, the distance from the phosphor to the outer circumference may be increased to improve the strength.

[0081] As described above, embodiments have been explained as examples of the technology in this disclosure. For this purpose, attached drawings and a detailed description have been provided. Therefore, among the components described in the attached drawings and detailed description, there may be not only components that are essential for solving the problem, but also components that are not essential for solving the problem, in order to illustrate the above technology. Therefore, the mere fact that these non-essential components are described in the attached drawings and detailed description should not be immediately assumed to mean that these non-essential components are essential.

[0082] Furthermore, since the embodiments described above are for illustrative purposes of the technology described herein, various modifications, substitutions, additions, omissions, etc., can be made within the claims or their equivalents.

[0083] (Summary of the embodiment) (1) The phosphor wheel of the present disclosure comprises a first substrate made of a metallic material having a first main surface and a second main surface opposite to the first main surface; a phosphor ring provided on the first main surface of the first substrate; a second substrate made of a metallic material having a third main surface disposed on the second main surface of the first substrate and a fourth main surface opposite to the third main surface; and a plurality of heat dissipation fins formed on the fourth main surface of the second substrate, wherein the second main surface of the first substrate and the third main surface of the second substrate are joined by brazing.

[0084] (2) In the phosphor wheel of (1), the first substrate has a circular shape when viewed from the first main surface side, and the second substrate has a circular shape when viewed from the fourth main surface side, the outer diameter of the first substrate and the outer diameter of the second substrate are equal, and the outer circumference of the first substrate and the outer circumference of the second substrate may overlap when viewed from the first main surface side of the first substrate.

[0085] (3) The phosphor wheel according to (1) or (2) further comprises a motor attached to a first substrate, wherein, when viewed from the first main surface side of the first substrate, a first hole is provided in the center of the first substrate for mounting the motor, and when viewed from the fourth main surface side of the second substrate, a second hole larger than the first hole is provided in the center of the second substrate.

[0086] (4) In any one of the phosphor wheels described in (1) to (3), at least a portion of the plurality of heat dissipation fins may be formed in a position that overlaps with the phosphor ring when viewed from the fourth main surface side of the second substrate.

[0087] (5) In any one of the phosphor wheels of (1) to (4), the second substrate has, when viewed from the fourth main surface side, a first annular flat portion formed inside the plurality of heat dissipation fins and a second annular flat portion formed outside the plurality of heat dissipation fins, wherein the first annular flat portion has a continuous flat annular shape, and the second annular flat portion has a continuous flat annular shape and may be formed along the outer circumference of the second substrate.

[0088] (6) In any one of the phosphor wheels described in (1) to (5), the multiple heat dissipation fins are formed integrally with the second substrate and may be bent in a direction intersecting the fourth main surface.

[0089] (7) In any one of the phosphor wheels described in (1) to (6), at least one of the first substrate and the second substrate is made of a clad material, and the clad material may have a plate-shaped base material made of a metal material and a brazing layer formed on at least one main surface of the base material.

[0090] In the phosphor wheel of (8)(7), the second substrate may be formed of a cladding material.

[0091] (9) In any one of the phosphor wheels described in (1) to (8), the thermal expansion coefficient of the metal material constituting the first substrate and the thermal expansion coefficient of the metal material constituting the second substrate may be equal.

[0092] (10) In any one of the phosphor wheels described in (1) to (9), the metal material constituting the first substrate and the metal material constituting the second substrate may be the same.

[0093] (11) The light source device of the present disclosure comprises one phosphor wheel from (1) to (10).

[0094] (12) The projection image display device of the present disclosure comprises the light source device of (11). [Industrial applicability]

[0095] This disclosure is applicable to phosphor wheels, light source devices, and projection image display devices. [Explanation of symbols]

[0096] 10A, 10B laser light source 11. Collimating lenses 12 Reflector 13 Transparent part 14. First substrate 14a First hole 15. Phosphor rings 16. Second substrate 16a Second hole 17 heat dissipation fins 17a aperture 18 Mounting part 19 Fixed flange 20 wax 21 Motor Flange 21a outer circumference 22 Inner circumference 23 Inner circumference 24 First annular flat section 25 Second annular flat section 100 Projection-type image display device 101a, 101b Laser Diode Unit 102 Partial Reflection Mirror 103, 108, 110, 112, 113 lenses 104, 109, 114, 122 Mirror 105, 115 Diffuser 106, 116, 117 Condenser lenses 107 Dichroic Mirror 111 Rod Integrator 118 Phosphor Wheel 119 Motor 120, 121 Relay Lens 123 Field Lens 124 Total Internal Reflection Prism 125 The First Prism 126 The Second Prism 127, 128 Prismatic plane 129 Color Prism Unit 130, 132 Dichroic mirror surface 131 The First Prism 133 The Second Prism 134 The Third Prism 135R, 135G, 135B Image Processing Unit (DMD) 136 projection lens

Claims

1. A first substrate made of a metallic material has a first main surface and a second main surface opposite to the first main surface, A phosphor ring provided on the first main surface of the first substrate, A second substrate made of a metal material, having a third main surface positioned on the second main surface of the first substrate, and a fourth main surface opposite to the third main surface, A plurality of heat dissipation fins formed on the fourth main surface of the second substrate, Equipped with, The second main surface of the first substrate and the third main surface of the second substrate are joined by brazing. Phosphor wheel.

2. The first substrate has a circular shape when viewed from the first main surface side, The second substrate has a circular shape when viewed from the fourth main surface side. The outer diameter of the first substrate and the outer diameter of the second substrate are equal. When viewed from the first main surface side of the first substrate, the outer periphery of the first substrate and the outer periphery of the second substrate overlap. The phosphor wheel according to claim 1.

3. The first substrate further comprises a motor mounted on it, Viewed from the first main surface side of the first substrate, a first hole is provided in the center of the first substrate for mounting the motor. When viewed from the fourth main surface side of the second substrate, a second hole larger than the first hole is provided in the center of the second substrate. The phosphor wheel according to claim 1 or 2.

4. At least a portion of the plurality of heat dissipation fins is formed in a position that overlaps with the phosphor ring when viewed from the fourth main surface side of the second substrate. A phosphor wheel according to any one of claims 1 to 3.

5. The second substrate, when viewed from the fourth main surface side, A first annular flat portion formed inside the plurality of heat dissipation fins, A second annular flat portion formed outside the plurality of heat dissipation fins, It has, The first annular flat portion has a continuous flat annular shape, The second annular flat portion has a continuous flat ring shape and is formed along the outer circumference of the second substrate. A phosphor wheel according to any one of claims 1 to 4.

6. The plurality of heat dissipation fins are formed integrally with the second substrate and are bent in a direction intersecting the fourth main surface. A phosphor wheel according to any one of claims 1 to 5.

7. At least one of the first substrate and the second substrate is formed of a clad material. The clad material comprises a plate-shaped base material made of a metal material and a brazing layer formed on at least one main surface of the base material. A phosphor wheel according to any one of claims 1 to 6.

8. The second substrate is formed of the cladding material. The phosphor wheel according to claim 7.

9. The thermal expansion coefficient of the metal material constituting the first substrate is equal to the thermal expansion coefficient of the metal material constituting the second substrate. A phosphor wheel according to any one of claims 1 to 8.

10. The metal material constituting the first substrate and the metal material constituting the second substrate are the same. A phosphor wheel according to any one of claims 1 to 9.

11. A light source device comprising a phosphor wheel according to any one of claims 1 to 10.

12. A projection-type image display device comprising the light source device described in claim 11.

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