Projection type image display device

Abstract

To provide a phosphor wheel in which imbalance in mass distribution is reduced.SOLUTION: A phosphor wheel 10 includes a disc-shaped substrate 20 having a first main surface 21, a second main surface 22 opposite to the first main surface 21, and an opening 23, and a phosphor layer that is provided on the first main surface 21 in a curved shape along the circumferential direction of the substrate 20, and is positioned in parallel to the opening 23 in the circumferential direction in a planar view. On the second main surface 22, a heat dissipation fin 25 and a protrusion 26 in a different form from the heat dissipation fin 25 are integrally formed with the substrate 20.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a phosphor wheel included in a field-sequential projection type image display device.

Background Art

[0002] A field-sequential projector including a wavelength conversion device called a phosphor wheel is known (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a phosphor wheel with reduced imbalance in mass distribution.

Means for Solving the Problems

[0005] A phosphor wheel according to an aspect of the present disclosure includes a disk-shaped substrate having a first main surface, a second main surface opposite to the first main surface, and an opening, and a phosphor layer provided in a curved shape along the circumferential direction of the substrate on the first main surface, the phosphor layer being positioned side by side with the opening in a plan view, and a heat dissipation fin and a convex portion having a different aspect from the heat dissipation fin are integrally formed with the substrate on the second main surface.

Effects of the Invention

[0006] According to the present disclosure, a phosphor wheel with reduced imbalance in mass distribution is realized.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

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Figure 5

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Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0008] [Findings on which the present disclosure is based] A field-sequential projection-type image display device that uses a digital micromirror device (DMD), an image display element capable of high-speed response, to sequentially switch the light of each of the RGB colors to achieve color display of an image has been put on the market.

[0009] Patent Document 1 discloses a field-sequential projection-type display device. The projection-type display device includes a color wheel (color filter) that sequentially and rapidly switches the color light of RGB. The color wheel is provided with a space portion without a color filter. In order to adjust the weight balance due to the formation of the space portion, a balance weight is provided on the central member of the color wheel.

[0010] Also, Patent Document 2 discloses a field-sequential projector. The projector includes a wavelength conversion device. The wavelength conversion device (hereinafter also referred to as a phosphor wheel) includes a disk having a first surface and a second surface, a wavelength conversion element provided on the first surface, and a heat sink provided on the second surface and separate from the base material. In such a wavelength conversion device, a balance adjustment member may be arranged to adjust the rotational balance of the disk.

[0011] By the way, when an opening is provided in the phosphor wheel, there is room for consideration regarding a method for reducing the imbalance in the mass distribution caused by the opening. The method of attaching a separate member as in Patent Documents 1 and 2 may be useful when finely adjusting the imbalance in the mass distribution, but it is not suitable when the opening is relatively large. In this specification, a phosphor wheel found in view of such problems is disclosed.

[0012] Hereinafter, embodiments will be specifically described with reference to the drawings. Note that all of the embodiments described below show comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps, order of steps, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. In addition, among the components in the following embodiments, the components not described in the independent claims are described as optional components.

[0013] Also, each figure is a schematic diagram and is not necessarily drawn precisely. In each figure, the same reference numerals are given to substantially the same configurations, and duplicate explanations may be omitted or simplified.

[0014] (Embodiment) [Configuration of Projection-Type Image Display Device] Hereinafter, a projection-type image display device according to an embodiment will be described. FIG. 1 is a diagram showing the configuration of the projection-type image display device according to the embodiment. In FIG. 1, the right direction is defined as the positive X-axis direction, the upward direction is defined as the positive Y-axis direction, and the direction toward the front side of the paper surface is defined as the positive Z-axis direction.

[0015] As shown in FIG. 1, the projection-type image display device 100 includes laser light sources 104a, 104b, 104c, condenser lenses 105, 106, a diffusion plate 107, a dichroic mirror 108, excitation lenses 109, 110, a phosphor wheel 10, a motor 113, relay lenses 132, 134, 136, 138, mirrors 133, 135, 137, a diffusion plate 139, a condenser lens 118, a color filter 119, a motor 120, a rod integrator 124, relay lenses 125, 126, folding mirrors 127, 128, a DMD 129, and a projection lens 130.

[0016] The laser light sources 104a, 104b, and 104c emit blue light for exciting the phosphor layer provided in the phosphor wheel 10. In other words, the laser light sources 104a, 104b, and 104c irradiate the phosphor layer with blue light. Note that the blue light is, for example, monochromatic light with a central wavelength of the emission spectrum of 455 nm. The laser light sources 104a, 104b, and 104c are realized by, for example, semiconductor lasers.

[0017] Each of the laser light sources 104a, 104b, and 104c includes a collimating lens at the emission port and emits blue parallel light forward (in the +X-axis direction). The emitted blue parallel light enters the condenser lens 105, and the light condensed by the condenser lens 105 enters the condenser lens 106. The condenser lens 106 is a concave lens. The blue parallel light emitted from the laser light sources 104a, 104b, and 104c is converted into parallel light with a smaller diameter by the condenser lens 106 and then enters the diffusion plate 107.

[0018] The diffusion plate 107 improves the uniformity of the blue parallel light by diffusing the blue parallel light incident on the diffusion plate 107. The light transmitted through the diffusion plate 107 enters the dichroic mirror 108.

[0019] The dichroic mirror 108 has the property of transmitting blue light and reflecting visible light having an emission color other than blue light. Since the light transmitted through the diffusion plate 107 is blue light, it passes through the dichroic mirror 108, is condensed by the excitation lenses 109 and 110, and a condensing spot is formed on the phosphor wheel 10.

[0020] As will be described later, in the phosphor wheel 10, the red phosphor layer, the green phosphor layer, and the openings are located on the same circumference, and the above-mentioned condensing spot is formed on this circumference. The red phosphor layer emits red fluorescence when irradiated with blue light, and the green phosphor layer emits green fluorescence when irradiated with blue light. When the phosphor wheel 10 is rotated by the motor 113, the emission of red fluorescence to the dichroic mirror 108 side, the emission of green fluorescence to the dichroic mirror 108 side, and the passage of blue light to the relay lens 132 side are sequentially performed.

[0021] The red fluorescence and green fluorescence emitted from the phosphor wheel 10 are incident on the dichroic mirror 108 through the excitation lenses 109 and 110. Since the dichroic mirror 108 has the property of reflecting visible light other than blue light as described above, it reflects the red fluorescence and green fluorescence, and the reflected red fluorescence and green fluorescence are incident on the color filter 119 through the condenser lens 118.

[0022] On the other hand, the blue light that has passed through the aperture provided in the phosphor wheel 10 is diffused by the diffusion plate 139 through the relay optical path of the blue light composed of the relay lenses 132, 134, 136, 138 and the mirrors 133, 135, 137. The diffused blue light passes through the dichroic mirror 108 and is incident on the color filter 119 through the condenser lens 118.

[0023] In this way, red fluorescence, green fluorescence, and blue light are incident on the color filter 119 in this order. FIG. 2 is a view of the color filter 119 as seen from the light incident side. As shown in FIG. 2, the color filter 119 includes a red transmission filter 121 that selectively transmits only red light, a green transmission filter 122 that selectively transmits only green light, and a transparent glass 123 obtained by applying an antireflection treatment to transparent glass.

[0024] The central portion of the color filter 119 is fixed to the motor hub of the motor 120, and the color filter 119 rotates in synchronization with the phosphor wheel 10 by the motor 120. Specifically, synchronization is taken such that the red fluorescence is incident on the red transmission filter 121, the green fluorescence is incident on the green transmission filter 122, and the blue light is incident on the transparent glass 123. According to the red transmission filter 121, unnecessary wavelength components contained in the red fluorescence are removed, and according to the green transmission filter 122, unnecessary wavelength components contained in the green fluorescence are removed. Thereby, the desired color purity is realized.

[0025] In this way, red light, green light, and blue light are emitted from the color filter 119 in a time-division manner. The light emitted from the color filter 119 enters the rod integrator 124, and after repeating total internal reflection within the rod integrator 124, it is emitted from the rod integrator 124. The light emitted from the rod integrator 124 enters the DMD 129 via the relay lenses 125 and 126 and the folding mirrors 127 and 128.

[0026] The DMD 129 is an example of an image display element, and modulates the light emitted from the phosphor wheel 10 (phosphor layer) according to the laser light irradiated by the laser light sources 104a, 104b, and 104c based on an image signal. The DMD 129 includes a base portion and a plurality of micromirrors provided on the base portion.

[0027] The tilt angle of each of the plurality of micromirrors is selectively changed in an either-or manner based on an image signal. Specifically, the tilt angle of each of the plurality of micromirrors is selectively changed between a first tilt angle that emits the light incident on the micromirror toward the projection lens 130 and a second tilt angle that emits the light incident on the micromirror in a direction not toward the projection lens 130.

[0028] During the period when red light is incident on the DMD 129, the DMD 129 emits a red image to the projection lens 130 based on the R signal of the image signal. During the period when green light is incident on the DMD 129, the DMD 129 emits a green image to the projection lens 130 based on the G signal of the image signal. During the period when blue light is incident on the DMD 129, the DMD 129 emits a blue image to the projection lens 130 based on the B signal of the image signal. That is, the operation of the DMD 129 is synchronized with the phosphor wheel 10 and the color filter 119, and the red image, green image, and blue image are switched at high speed.

[0029] The projection lens 130 projects the light (i.e., the image) modulated by the DMD 129. A color image is projected onto the screen by the projection lens 130.

[0030] Note that, instead of the DMD129, a reflective liquid crystal panel (LCOS: Liquid Crystal On Silicon) may be used as the image display element. Further, the projection type image display device 100 may include a transmissive image display element such as a transmissive liquid crystal panel, instead of the reflective image display element such as the DMD129 and the reflective liquid crystal panel.

[0031] As described above, the projection type image display device 100 can display a color image.

[0032] [Configuration of the phosphor wheel] Next, the structure of the phosphor wheel 10 will be described in detail. FIG. 3 is a plan view of the phosphor wheel according to the embodiment as viewed from the first main surface side. FIG. 4 is a plan view of the phosphor wheel according to the embodiment as viewed from the second main surface side. FIG. 5 is a perspective view of the phosphor wheel according to the embodiment as viewed from the second main surface side. Note that the first main surface is the main surface of the phosphor wheel 10 on the dichroic mirror 108 side, and the second main surface is the main surface on the side opposite to the first main surface. In the following embodiments, the radial direction of the circle centered on the virtual rotation axis J (illustrated in FIGS. 3 to 5) is denoted as the radial direction r (illustrated in FIGS. 3 and 4), and the circumferential direction of the circle centered on the rotation axis J is denoted as the circumferential direction θ (illustrated in FIG. 5).

[0033] As shown in FIGS. 3 to 5, the phosphor wheel 10 includes a substrate 20 and a phosphor layer 30. The phosphor wheel 10 is an optical member used in the projection type image display device 100. The phosphor layer 30 included in the phosphor wheel 10 emits light when irradiated with laser light. At this time, half of the energy becomes heat, but when the temperature of the phosphor particles included in the phosphor layer 30 exceeds a certain temperature, the conversion efficiency decreases and the amount of heat generation increases. When the amount of heat generation increases, concerns about reliability such as deterioration of the resin material included in the phosphor layer 30 arise.

[0034] Therefore, in order to avoid the laser light being intensively irradiated on a single point of the phosphor layer 30, while the phosphor layer 30 is irradiated with the laser light, the phosphor wheel 10 rotates about the rotation axis J by the motor 113. Thereby, it is suppressed that the laser light continues to irradiate the same location of the phosphor layer 30. That is, it is suppressed that the phosphor particles contained in the phosphor layer 30 are deteriorated due to heat generation. Further, the substrate 20 is formed of a heat conductive material such as aluminum, whereby the heat dissipation property of the phosphor layer 30 is enhanced.

[0035] The substrate 20 is a disk-shaped substrate centered on the rotation axis J. In other words, the shape of the substrate 20 in plan view is circular. Note that the shape in plan view is, in other words, the shape when viewed from a direction perpendicular to the first main surface 21 (or the second main surface 22) of the substrate 20. The substrate 20 has a first main surface 21, a second main surface 22 on the opposite side of the first main surface 21, and an opening 23.

[0036] Further, a main opening 24 is provided at the center of the substrate 20, and a rotor of a motor (not shown in FIGS. 3 to 5) is connected to the main opening 24. The rotation axis J passes through the center (center position) of the substrate 20, and the substrate 20 is rotated about the rotation axis J by the motor. The substrate 20 is formed of a metal having good thermal conductivity such as aluminum, an alloy containing aluminum, or copper, for example.

[0037] The phosphor layer 30 is provided on the first main surface 21 of the substrate 20. The phosphor layer 30 is curved along the circumferential direction θ of the substrate 20. That is, the phosphor layer 30 is arc-shaped. The phosphor layer 30 is positioned side by side with the opening 23 in the circumferential direction θ. That is, the phosphor layer 30 and the opening 23 are located on the same circumference. Further, in the phosphor wheel 10, the width of the phosphor layer 30 in the radial direction r is constant, and the width of the phosphor layer 30 in the radial direction r is the same as the width of the opening 23 in the radial direction r.

[0038] The phosphor layer 30 specifically includes a red phosphor layer 30r and a green phosphor layer 30g. The red phosphor layer 30r is formed of a resin material containing a large number of red phosphor particles. The red phosphor particles are specifically CaAlSiN 3 :Eu 2+ or (Sr,Ca)AlSiN 3 :Eu 2+ and the like. Note that the red phosphor layer 30r may contain phosphor particles that emit fluorescence of colors other than red.

[0039] The green phosphor layer 30g is formed of a resin material containing a large number of green phosphor particles. The green phosphor particles are specifically Y 3 (Al,Ga) 5 O 12 :Ce 3+ or Lu 3 Al 5 O 12 :Ce 3+ and the like. Note that the green phosphor layer 30g may contain phosphor particles that emit fluorescence of colors other than green.

[0040] The base material of the resin material is, for example, a silicone resin having translucency and thermosetting properties. The phosphor layer 30 is formed, for example, by adhering a cured resin material containing separately generated phosphor particles to the substrate 20 with an adhesive having light reflectivity. The adhesive is formed of, for example, a resin binder containing titanium oxide and also functions as a light reflection layer. Note that the phosphor layer 30 may be formed by screen-printing a resin material containing phosphor particles on the first main surface 21 of the substrate 20 and then heat-curing it in a heating furnace. Although not shown in FIGS. 3 to 5, a light reflection film may be provided between the first main surface 21 of the substrate 20 and the phosphor layer 30.

[0041] Each of the red phosphor layer 30r and the green phosphor layer 30g is curved along the circumferential direction θ, and one end portions in the circumferential direction θ are connected to each other. Further, in a plan view, an opening 23 is located between the other end portion of the red phosphor layer 30r and the other end portion of the green phosphor layer 30g, and the opening 23 is also curved along the circumferential direction θ. Note that the opening 23 is a through hole for transmitting laser light (blue light).

[0042] With such a configuration, the phosphor wheel 10 can incident red, green, and blue light on the DMD 129 in a time-division manner.

[0043] Note that it is not essential for the phosphor layer 30 to include the red phosphor layer 30r and the green phosphor layer 30g, and the phosphor layer 30 may be a single yellow phosphor layer formed of a resin material containing a large number of yellow phosphor particles. The yellow phosphor particles are, for example, YAG-based yellow phosphor particles. Even such a phosphor layer 30 can incident red, green, and blue light on the DMD 129 in a time-division manner by using the color filter 119 in combination.

[0044] In order to enhance the heat dissipation property of the phosphor layer 30, a plurality of heat radiation fins 25 are provided on the second main surface 22 of the substrate 20. The plurality of heat radiation fins 25 are provided over substantially the entire second main surface 22 of the substrate 20. In a plan view, each of the plurality of heat radiation fins 25 is in an arc shape not centered on the rotation axis J, and the plurality of heat radiation fins 25 form a spiral shape as a whole. Note that it is not essential for the plurality of heat radiation fins 25 to form a spiral shape. The plurality of heat radiation fins 25 may be arranged in any manner, such as being arranged radially. The arrangement of the plurality of heat radiation fins 25 may be appropriately determined empirically or experimentally.

[0045] The plurality of heat radiation fins 25 are formed integrally with the substrate 20 (more specifically, the main body of the substrate 20), for example, by cutting the base material of the substrate 20. The cutting is performed by a tool such as an end mill, for example, but may also be performed by a laser. The plurality of heat radiation fins 25 have cutting marks.

[0046] On the second main surface 22 of the substrate 20, convex portions 26 are provided in a manner different from that of the heat radiation fins 25. While the plurality of heat radiation fins 25 are in a spiral shape as a whole, the convex portions 26 are in a curved shape along the circumferential direction θ (in other words, in an arc shape centered on the rotation axis J). Similar to the plurality of heat radiation fins 25, the convex portions 26 are integrally formed with the substrate 20 by machining the base material of the substrate 20. The convex portions 26 have cutting marks.

[0047] The convex portions 26 are provided to reduce the imbalance (moment imbalance) of the mass distribution of the phosphor wheel 10 due to the provision of the openings 23. In other words, the convex portions 26 are provided at positions such that the imbalance of the mass distribution of the phosphor wheel 10 due to the provision of the openings 23 is reduced.

[0048] Specifically, the convex portions 26 are located on the outer peripheral side of the openings 23 and are aligned with the openings 23 in the radial direction r. In this way, if the convex portions 26 are located in the region on the outer peripheral side of the openings 23, the imbalance of the mass distribution caused by the openings 23 can be reduced by the convex portions 26 having a mass smaller than the mass reduced by the provision of the openings 23. That is, it is possible to reduce the imbalance of the mass distribution while suppressing an increase in the overall weight. Further, if the convex portions 26 are in a curved shape along the openings 23, the periphery of the openings 23 can be structurally reinforced. The mass of the convex portions 26 is determined by the height of the convex portions 26, the length of the convex portions 26 in the circumferential direction θ, and the width of the convex portions 26 in the radial direction r. The height of the convex portions 26 is, in other words, the length of the convex portions 26 in the direction perpendicular to the second main surface 22.

[0049] By adjusting the positions and masses of the convex portions 26, the residual imbalance of the phosphor wheel 10 is equal to or less than the allowable residual imbalance. It is possible to set the design residual imbalance to 0.

[0050] Incidentally, in the phosphor wheel 10, the region 27 around the opening 23 in the second main surface 22 is flat, and no heat dissipation fins 25 and convex portions 26 are provided in the peripheral region 27. As a result, the laser light passing through the opening 23 hits the plurality of heat dissipation fins 25 and convex portions 26, and it is suppressed that stray light (unnecessary light) or a heat generation source is generated. Note that the maximum dimension of the width of the convex portion 26 in the radial direction r is limited so that the laser light passing through the opening 23 does not hit it. When the laser light does not hit the plurality of heat dissipation fins 25 and convex portions 26, the plurality of heat dissipation fins 25 and convex portions 26 may reach the vicinity of the end face of the opening 23.

[0051] Further, the height of the convex portion 26 may be different from the height of the heat dissipation fin 25, but in the phosphor wheel 10, the height of the convex portion 26 is the same as the height of the heat dissipation fin 25. If the height of the convex portion 26 is the same as the height of the heat dissipation fin 25, the plurality of heat dissipation fins 25 and convex portions 26 can be formed in the same cutting process. That is, the manufacturing process of the phosphor wheel 10 (substrate 20) can be simplified, and cost reduction can be achieved. When the height of the convex portion 26 and the height of the heat dissipation fin 25 are the same, the mass of the convex portion 26 may be adjusted mainly by the length in the circumferential direction θ.

[0052] Hereinafter, the merits obtained by the phosphor wheel 10 will be described based on a comparison with the phosphor wheel according to the comparative example. FIG. 6 is a plan view when the phosphor wheel according to the comparative example is viewed from the first main surface side, and FIG. 7 is a plan view when the phosphor wheel according to the comparative example is viewed from the second main surface side.

[0053] The phosphor wheel 10h shown in FIGS. 6 and 7 includes a substrate 20h provided with a phosphor layer 30 on the first main surface 21h and a plurality of heat dissipation fins 25h on the second main surface 22h. Further, an opening 23h is provided in the substrate 20h. In order to reduce the imbalance in the mass distribution of the phosphor wheel 10h due to the provision of the opening 23h in the substrate 20h, an opening 26h is provided.

[0054] Thus, in order to reduce the imbalance in the mass distribution by the opening 26h, the opening 26h needs to be provided on the opposite side across the opening 23h and the rotation axis J and not to overlap with the phosphor layer 30. Then, due to space constraints, the opening 26h is provided on the inner circumferential side of the phosphor layer 30. In order to eliminate the imbalance in the mass distribution, the opening 26h needs to be formed larger than the opening 23h. When the opening 26h is large, there are demerits such as deterioration of the flatness of the region where the phosphor layer 30 of the first main surface 21h is provided, or deterioration of the heat dissipation due to a decrease in the heat capacity of the substrate 20h.

[0055] On the other hand, in the phosphor wheel 10, by reducing the imbalance in the mass distribution of the phosphor wheel 10 by the convex portion 26, it is possible to suppress deterioration of the flatness of the first main surface 21 and deterioration of the heat dissipation.

[0056] [Modification Example 1] When there is concern about a decrease in the strength of the substrate 20 due to the long length of the opening 23 in the circumferential direction θ, by providing openings at two or more locations, the length of one opening in the circumferential direction θ can be shortened. FIG. 8 is a plan view when the phosphor wheel according to such a modification example 1 is viewed from the first main surface side. FIG. 9 is a plan view when the phosphor wheel according to the modification example 1 is viewed from the second main surface side. In the modification example 1, descriptions of the same matters as those of the phosphor wheel 10 are appropriately omitted, and the description is centered on the differences from the phosphor wheel 10.

[0057] The phosphor wheel 10a shown in FIGS. 8 and 9 includes a substrate 20a provided with a phosphor layer 30a on the first main surface 21a and a plurality of heat dissipation fins 25a on the second main surface 22a. Further, two openings 23a are provided in the substrate 20a.

[0058] The red phosphor layer 30r and the green phosphor layer 30g included in the phosphor layer 30a are located side by side with the two openings 23a in the circumferential direction θ. That is, the red phosphor layer 30r, the green phosphor layer 30g, and the two openings 23a are located on the same circumference.

[0059] On the second main surface 22a, two convex portions 26a corresponding to the two openings 23a are provided. Each of the two convex portions 26a is curved along the circumferential direction θ, is located on the outer peripheral side of the corresponding opening 23a, and is arranged side by side with the corresponding opening 23a in the radial direction r.

[0060] Thus, when two openings 23a are provided in the substrate 20a, by providing the convex portions 26 on the outer peripheral side of each of the two openings 23a, the imbalance of the mass distribution of the phosphor wheel 10a can be reduced.

[0061] [Modification 2] Further, when two openings 23a are provided in the substrate 20a like the phosphor wheel 10a, it is not essential to provide two convex portions 26a. That is, the number of openings 23a and the number of convex portions do not have to match. FIG. 10 is a plan view of the phosphor wheel according to Modification 2 as viewed from the second main surface side. FIG. 11 is a perspective view of the phosphor wheel according to Modification 2 as viewed from the second main surface side. In Modification 2, descriptions of the same matters as those of the phosphor wheels 10 and 10a are appropriately omitted, and the description is centered on the differences from the phosphor wheel 10.

[0062] The plan view of the phosphor wheel 10b shown in FIGS. 10 and 11 as viewed from the first main surface 21b side is the same as FIG. 8. That is, the configuration on the first main surface 21b side of the phosphor wheel 10b is the same as that of the phosphor wheel 10a. A plurality of heat dissipation fins 25b are provided on the second main surface 22b of the substrate 20b included in the phosphor wheel 10b. Further, two openings 23b are provided in the substrate 20b.

[0063] On the second main surface 22b, one convex portion 26b is provided for the two openings 23b. The convex portion 26b is curved along the circumferential direction θ and is located in the region between the two openings 23b on the outer peripheral side of the two openings 23b.

[0064] As described above, when two openings 23b are provided in the substrate 20b, the unbalance of the mass distribution of the phosphor wheel 10b can also be reduced by providing one convex portion 26b in the region between the two openings 23b. If the convex portion 26b is arranged avoiding the vicinity of the opening 23b, it is possible to suppress the laser light transmitted through the opening 23b from hitting the convex portion 26b and becoming stray light (unnecessary light) or a heat generation source.

[0065] [Modification 3] In the phosphor wheels 10, 10a, and 10b, the shape of the convex portion was a curved shape (in other words, an arc shape) along the circumferential direction θ, but the shape of the convex portion is not particularly limited. FIG. 12 is a perspective view of the phosphor wheel according to Modification 3 as viewed from the second main surface side. In Modification 3, descriptions of the same matters as those of the phosphor wheel 10 are appropriately omitted, and the description will be centered on the differences from the phosphor wheel 10.

[0066] A plan view of the phosphor wheel 10c according to Modification 3 as viewed from the first main surface 21c side is the same as FIG. 5, and thus the illustration and description thereof are omitted. An opening 23c is provided in the substrate 20c included in the phosphor wheel 10c. A plurality of heat radiation fins 25c are provided on the second main surface 22c of the substrate 20c.

[0067] In addition, a plurality of convex portions 26c are provided on the second main surface 22c of the substrate 20 in a different manner from the heat radiation fins 25c. Each of the plurality of convex portions 26c is dot-shaped. The plurality of convex portions 26 are located on the outer peripheral side of the opening 23, and each of the plurality of convex portions 26c is positioned side by side with the opening 23c in the radial direction r. Further, the plurality of convex portions 26c are arranged side by side along the circumferential direction θ.

[0068] In this way, the unbalance of the mass distribution of the phosphor wheel 10c can also be reduced by the plurality of dot-shaped convex portions 26c.

[0069] [Effects, etc.] As described above, the phosphor wheel 10 includes a disk-shaped substrate 20 having a first main surface 21, a second main surface 22 opposite to the first main surface 21, and an opening 23, and a phosphor layer 30 provided in a curved shape along the circumferential direction θ of the substrate 20 on the first main surface 21, the phosphor layer 30 being positioned side by side with the opening 23 in a plan view. On the second main surface 22, a heat dissipation fin 25 and a convex portion 26 having a different form from the heat dissipation fin 25 are integrally formed with the substrate 20.

[0070] Thereby, the imbalance of the mass distribution of the phosphor wheel 10 can be reduced by the convex portion 26. That is, it can be said that the phosphor wheel 10 is a phosphor wheel in which the imbalance of the mass distribution is reduced by the convex portion 26.

[0071] Also, for example, the convex portion 26 is located in a region on the outer peripheral side of the opening 23 in the second main surface 22.

[0072] Thereby, the imbalance of the mass distribution caused by the opening 23 can be reduced by the convex portion 26 having a mass smaller than the mass reduced by the provision of the opening 23.

[0073] Also, for example, the convex portion 26 is positioned side by side with the opening 23 in the radial direction of the substrate 20.

[0074] Thereby, the periphery of the opening 23 can be structurally reinforced by the convex portion 26.

[0075] Also, for example, the convex portion 26 is formed in a curved shape along the circumferential direction θ.

[0076] Thereby, the periphery of the opening 23 can be structurally reinforced by the convex portion 26.

[0077] Also, for example, the height of the convex portion 26 is the same as the height of the heat dissipation fin 25.

[0078] Thereby, the plurality of heat dissipation fins 25 and the convex portions 26 can be formed in the same cutting process.

[0079] Further, for example, the convex portion 26 is formed at a position where the imbalance of the mass distribution of the phosphor wheel 10 caused by the opening 23 is reduced.

[0080] Thereby, the imbalance of the mass distribution of the phosphor wheel 10 can be reduced by the convex portion 26.

[0081] Further, for example, the residual unbalance of the phosphor wheel 10 is equal to or less than the allowable residual unbalance.

[0082] Thereby, a phosphor wheel 10 in which the residual unbalance is equal to or less than the allowable residual unbalance is realized.

[0083] Further, for example, a region 27 around the opening 23 in the second main surface 22 is flat.

[0084] Thereby, the laser light passing through the opening 23 hits the plurality of heat dissipation fins 25 and the convex portion 26, and it is suppressed that the laser light becomes stray light (unnecessary light) or a heat generation source.

[0085] Further, for example, the heat dissipation fins 25 and the convex portion 26 are formed by cutting.

[0086] Thereby, the heat dissipation fins 25 and the convex portion 26 can be formed by cutting.

[0087] Further, in the phosphor wheel 10b, the substrate 20b has a plurality of openings 23b, and one convex portion 26b is provided for the plurality of openings 23b, so that the imbalance of the mass distribution of the phosphor wheel 10b is reduced.

[0088] Thereby, the convex portion 26b can be arranged at a position away from the plurality of openings 23b, and it is suppressed that the laser light passing through the openings 23b hits the convex portion 26b and becomes stray light (unnecessary light) or a heat generation source.

[0089] In the phosphor wheel 10c, a plurality of convex portions 26c are formed in a dot shape along the circumferential direction θ.

[0090] As a result, the imbalance in the mass distribution of the phosphor wheel 10c can be reduced by the plurality of convex portions 26c each in a dot shape.

[0091] The projection type image display device 100 includes a phosphor wheel 10, a motor 113 that rotates the phosphor wheel 10, laser light sources 104a, 104b, 104c that irradiate the phosphor layer 30 with laser light, a DMD 129 that modulates the light emitted from the phosphor layer 30 according to the laser light irradiated by the laser light sources 104a, 104b, 104c based on an image signal, and a projection lens 130 that projects the light modulated by the DMD 129. The DMD 129 is an example of an image display element. The projection type image display device 100 may include phosphor wheels 10a, 10b, 10c instead of the phosphor wheel 10.

[0092] Such a projection type image display device 100 has improved reliability by including a phosphor wheel 10 with a reduced imbalance in mass distribution.

[0093] (Other Embodiments) Although the embodiments have been described above, the present disclosure is not limited to the above embodiments.

[0094] For example, in the above embodiment, the convex portion is disposed on the outer peripheral side of the substrate rather than the opening, but it may be disposed on the inner peripheral side of the substrate rather than the opening.

[0095] Although the embodiments have been described above, the present invention is not limited to the above embodiments.

[0096] Also, in the above embodiment, the laser light source was described as a semiconductor laser, but it may be a laser other than a semiconductor laser. The laser light source may be, for example, a solid-state laser such as a YAG laser, a liquid laser such as a dye laser, or a gas laser such as an Ar ion laser, a He-Cd laser, a nitrogen laser, or an excimer laser.

[0097] Furthermore, the overall or specific aspects of the present disclosure may be implemented by any of a system, an apparatus, and a method. For example, the present disclosure may be implemented as a method for manufacturing a phosphor wheel. Such a manufacturing method includes a step of creating a substrate by cutting and a step of forming a phosphor layer on the created substrate.

[0098] In addition, forms obtained by applying various modifications conceivable by those skilled in the art to each of the embodiments and modification examples, and forms realized by arbitrarily combining the components and functions in the embodiments without departing from the gist of the present invention are also included in the present invention.

Industrial Applicability

[0099] The present disclosure is useful as a phosphor wheel used in a field-sequential projection-type image display device.

Explanation of Signs

[0100] 10, 10a, 10b, 10c, 10h Phosphor wheel 20, 20a, 20b, 20c, 20h Substrate 21, 21a, 21b, 21c, 21h First main surface 22, 22a, 22b, 22c, 22h Second main surface 23, 23a, 23b, 23c, 23h, 26h Opening 24 Main opening 25, 25a, 25b, 25c, 25h Heat dissipation fin 26, 26a, 26b, 26c Protrusion 27 Region 30, 30a Phosphor layer 30g Green phosphor layer 30r Red phosphor layer 100 Projection type image display device 104a, 104b, 104c Laser light source 105, 106, 118 Condensing lens 107, 139 Diffusion plate 108 Dichroic mirror 109, 110 Excitation lens 113, 120 Motor 119 Color filter 121 Red transmission filter 122 Green transmission filter 123 Transparent glass 124 Rod integrator 125, 126, 132, 134, 136, 138 Relay lens 127, 128, 133, 135, 137 Mirror 130 Projection lens J Axis of rotation r Radial direction θ Circumferential direction

Claims

1. a disk-shaped substrate having a first main surface, a second main surface opposite the first main surface, and an opening; a phosphor layer provided on the first main surface in a curved shape along a circumferential direction of the substrate, the phosphor layer being aligned with the opening in the circumferential direction in a plan view; The second main surface is provided with a heat dissipation fin and a protrusion having a different configuration from the heat dissipation fin, the protrusion being integrally formed with the substrate. Phosphor wheel.

2. The protrusion is located in a region of the second main surface that is on the outer circumferential side of the opening. The phosphor wheel of claim 1 .

3. The protrusion is positioned alongside the opening in the radial direction of the substrate. The phosphor wheel according to claim 1 .

4. The protruding portion is formed in a curved shape along the circumferential direction. The phosphor wheel according to any one of claims 1 to 3.

5. The protrusions are formed in a dot pattern along the circumferential direction. The phosphor wheel according to any one of claims 1 to 3.

6. The height of the protrusion is the same as the height of the heat dissipation fin. The phosphor wheel according to any one of claims 1 to 5.

7. The convex portion is formed at a position that reduces an imbalance in the mass distribution of the phosphor wheel caused by the opening. The phosphor wheel according to any one of claims 1 to 6.

8. The residual imbalance of the phosphor wheel is less than or equal to the allowable residual imbalance. The phosphor wheel of claim 7 .

9. the substrate has a plurality of the openings; By providing one protrusion for a plurality of the openings, imbalance in mass distribution of the phosphor wheel is reduced. The phosphor wheel according to claim 1 .

10. The second main surface has a flat area around the opening. The phosphor wheel according to any one of claims 1 to 9.

11. The heat dissipation fins and the protrusions are formed by cutting. The phosphor wheel according to any one of claims 1 to 10.

12. A phosphor wheel according to any one of claims 1 to 11, a motor for rotating the phosphor wheel; a laser light source that irradiates the phosphor layer with laser light; an image display element that modulates light emitted from the phosphor layer in response to the laser light irradiated by the laser light source based on an image signal; a projection lens that projects the light modulated by the image display element. Projection type image display device.

Images