Light source device and projection-type video display device

Abstract

A light-source device according to the present invention includes: a light source; a wavelength conversion element that converts excitation light from the light source into light of a different wavelength range; a wavelength selection element that reflects light of a specific wavelength range from among the light from the wavelength conversion element; and a light separation means that is disposed on an optical path of the wavelength-converted light from the wavelength conversion element to the wavelength selection element, and that separates light of a specific wavelength range from the wavelength-converted light from the wavelength conversion element and guides said light to outside of the optical path.

Description

Light source device and projection type video display device

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

[0002] Conventionally, as a component of a projection type video display device such as a projector, a phosphor wheel provided with a phosphor that is excited by light from a light source and emits fluorescence has been used. For example, Patent Document 1 discloses a light source device including a light source that emits light, a phosphor wheel, a wavelength selective wheel, and a phase adjustment unit that adjusts the phase between the phosphor wheel and the wavelength selective wheel. The phosphor wheel is provided rotatably, and a phosphor that is excited by light from the light source and emits fluorescence is arranged. Further, the wavelength selective wheel is provided rotatably and has a region that removes a part of the wavelength band of the fluorescence and transmits the light from the light source.

[0003] Japanese Patent Application Laid-Open No. 2014-186081

[0004] The present disclosure has been devised in view of the above-described conventional circumstances, and an object thereof is to suppress the temperature rise of the wavelength conversion element.

[0005] The present disclosure provides a light source device including a light source, a wavelength conversion element that wavelength-converts excitation light from the light source into light in a different wavelength range, a wavelength selection element that reflects light in a specific wavelength range among the light from the wavelength conversion element, and a light separation unit that is disposed on an optical path of the wavelength-converted light from the wavelength conversion element to the wavelength selection element, separates light in a specific wavelength range from the wavelength-converted light from the wavelength conversion element, and guides it outside the optical path.

[0006] Further, the present disclosure provides a projection type video display device including a light source device including a light source, a wavelength conversion element that wavelength-converts excitation light from the light source into light in a different wavelength range, a wavelength selection element that reflects light in a specific wavelength range among the light from the wavelength conversion element, and a light separation unit that is disposed on an optical path of the wavelength-converted light from the wavelength conversion element to the wavelength selection element, separates light in a specific wavelength range from the wavelength-converted light from the wavelength conversion element, and guides it outside the optical path.

[0007] Furthermore, any combination of the above components, as well as any conversion of the expressions of this disclosure between methods, apparatus, systems, etc., are also valid as aspects of this disclosure.

[0008] According to this disclosure, it is possible to suppress the temperature rise of the wavelength conversion element.

[0009] Schematic diagram showing an example configuration of the light source device according to Embodiment 1 Front view showing an example configuration of the phosphor wheel according to Embodiment 1 Cross-sectional diagram showing the AA cross-section of the phosphor wheel according to Embodiment 1 Cross-sectional diagram showing the BB cross-section of the phosphor wheel according to Embodiment 1 Front view showing an example configuration of the color wheel according to Embodiment 1 Cross-sectional diagram showing the cross-section of the phosphor wheel according to Modification 1 of Embodiment 1 Schematic diagram showing an example configuration of the light source device according to Modification 2 of Embodiment 1 Front view showing an example configuration of the phosphor wheel according to Modification 2 of Embodiment 1 Front view showing an example configuration of the color wheel according to Modification 2 of Embodiment 1 Cross-sectional diagram showing the CC cross-section of the color wheel according to Modification 2 of Embodiment 1 Schematic diagram showing the time-series light emission sequence of the light source device according to Modification 2 of Embodiment 1 Front view showing an example configuration of the color wheel according to Modification 2 of Embodiment 1 Schematic diagram showing the time-series light emission sequence of the light source device according to Modification 2 of Embodiment 1 Schematic diagram showing an example configuration of the light source device according to Modification 3 of Embodiment 1 Schematic diagram showing an example configuration of the light source device according to Embodiment 2 Schematic diagram showing an example configuration of the light source device according to Modification 1 of Embodiment 2 Schematic diagram showing an example configuration of the light source device according to Embodiment 3 Front view showing an example of the configuration of the color wheel Front view showing an example of the configuration of the phosphor wheel according to Embodiment 3 Schematic diagram showing the time-series light emission sequence of the light source device according to Embodiment 3 Front view showing an example of the configuration of the phosphor wheel according to Embodiment 3 Schematic diagram showing the time-series light emission sequence of the light source device according to Embodiment 3 Schematic diagram showing an example of the configuration of the light source device according to Modification 1 of Embodiment 3 Schematic diagram showing an example of the configuration of the light source device according to Modification 2 of Embodiment 3 Schematic diagram showing an example of the configuration of the light source device according to Embodiment 4 Front view showing an example of the configuration of the phosphor wheel according to Embodiment 4 Schematic diagram showing an example of the configuration of the light source device according to Modification 1 of Embodiment 4 Schematic diagram showing an example of the configuration of the light source device according to Modification 2 of Embodiment 4 Schematic diagram showing an example of the configuration of the light source device according to Modification 2 of Embodiment 4 Schematic diagram showing an example of the configuration of the light source device according to Embodiment 5 Schematic diagram showing an example of the configuration of the light source device according to Modification 1 of Embodiment 5 Schematic diagram showing an example of the configuration of the light source device according to Modification 2 of Embodiment 5 Schematic diagram showing an example of the configuration of a projection-type video display device including a light source device according to Modification 3 of Embodiment 1 Schematic diagram showing an example of the configuration of a projection-type video display device including a light source device according to Modification 2 of Embodiment 4 Schematic diagram showing an example of the configuration of a projection-type video display device including a light source device according to Modification 2 of Embodiment 5

[0010] (Background to this Disclosure) The luminous efficiency of wavelength conversion elements used in projection-type image display devices such as projectors decreases with increasing temperature. Furthermore, if the temperature of the wavelength conversion element exceeds an upper limit, or more specifically, if the temperature of the phosphor layer of the wavelength conversion element exceeds an upper limit, burnout may occur. Therefore, it is necessary to suppress the temperature rise of the wavelength conversion element. However, in the projection-type image display device of Patent Document 1, when red light is emitted from the color trim wheel, the red light emitted from the wavelength conversion element (phosphor wheel) is obtained by removing the green fluorescence region from the yellow fluorescence emitted. At this time, the green fluorescence removed from the yellow fluorescence is reflected by the color trim wheel and guided to the wavelength conversion element, and the temperature of the wavelength conversion element may rise due to the concentration of green fluorescence. Therefore, in the following embodiment, a technique for suppressing the temperature rise of the wavelength conversion element will be described even when light in a specific wavelength range from the light emitted from the wavelength conversion element is guided to the wavelength conversion element.

[0011] Hereinafter, embodiments specifically disclosing the light source device and projection-type image display device according to this disclosure will be described in detail, with appropriate reference to the attached drawings. However, unnecessarily detailed explanations may be omitted. For example, detailed explanations of already well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding by those skilled in the art. The attached drawings and the following explanation are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter described in the claims.

[0012] In the drawings, equivalent components are indicated by the same reference numeral. When describing the various embodiments shown in this specification, if a component included in each embodiment requires individual explanation, a subscript (a, b, ...) is added to the reference numeral. On the other hand, when a component is described in common, the subscript is omitted from the reference numeral.

[0013] Furthermore, in this specification, terms such as "first" and "second" are used merely to distinguish components for explanatory purposes and are not intended to be interpreted as limiting to any particular component. Therefore, these expressions should be understood to be appropriately reinterpreted depending on the configuration to which the invention relating to this disclosure applies.

[0014] Furthermore, each figure shows a three-dimensional coordinate system consisting of the x, y, and z axes, and the orientation of each axis is assumed to correspond to that of the other. In addition, the dimensions and arrangement of each layer in the figures described below are simplified for illustrative purposes and are not intended to be interpreted restrictively unless otherwise specified.

[0015] One embodiment of the light source device according to this disclosure is used, for example, in a projection-type image display device such as a projector. The control method for the light source device within the projection-type image display device may be a known method, and a detailed explanation is omitted here.

[0016] The following description will explain a light source device relating to Embodiment 1 and its modified form using Figures 1 to 13. Furthermore, a light source device relating to Embodiment 2 and its modified form will be explained using Figures 14 and 15. A light source device relating to Embodiment 3 and its modified form will be explained using Figures 16 to 23. A light source device relating to Embodiment 4 and its modified form will be explained using Figures 24 to 27. A light source device relating to Embodiment 5 will be explained using Figures 28 to 30. Finally, various examples of projection-type image display devices including a light source device will be explained using Figures 31 to 33. Note that the combination of the light source device and the projection-type image display device may be arbitrary unless otherwise specified below. Therefore, the configuration examples and combinations described below are merely examples and are not limiting. Note that a light source device according to one embodiment of this disclosure includes a phosphor wheel as a wavelength conversion element. However, in this disclosure, the wavelength conversion element is not limited to a phosphor wheel. For example, a light source device according to one embodiment of this disclosure may include a fixed-type wavelength conversion element. Also, a light source device according to one embodiment of this disclosure may include a color wheel, which is a time-division wavelength selector, as a wavelength selector element. However, in this disclosure, the wavelength-selective element is not limited to a color wheel. For example, a light source device according to one embodiment of this disclosure may include a fixed wavelength-selective element.

[0017] [Light Source Device] <Embodiment 1> Figure 1 is a schematic diagram showing an example of the configuration of a light source device 10a according to Embodiment 1.

[0018] The light source device 10a includes an optical system in which light emitted from the laser diode light source 11 loops, and is configured to emit light of different wavelengths such as blue, green, and red in a time series. The light source device 10a is a light source device suitable for projection-type image display devices that use a single-panel Digital Mirror Device (hereinafter referred to as "DMD"), which will be described later.

[0019] The light source device 10a is composed of an excitation light optical system, a blue loop optical system, a fluorescence illumination system, an InfraRed (hereinafter referred to as "IR") separated illumination system, and a time-series integrator illumination system.

[0020] The excitation light optical system of the light source device 10a consists of multiple laser diode light sources 11, multiple collimator lenses 12, a convex lens 13, a diffuser plate 14, a concave lens 15, a dichroic mirror 16a, a convex lens 17, and a convex lens 18.

[0021] The blue loop optical system of the light source device 10a consists of a phosphor wheel 19a, a convex lens 20, a convex lens 21, a total reflection mirror 22, a convex lens 23, a total reflection mirror 24, a convex lens 25, a total reflection mirror 26, a convex lens 27, a dichroic mirror 16a, an IR-separating dichroic mirror 28a, and a convex lens 30.

[0022] The fluorescent illumination system of the light source device 10a consists of a convex lens 18, a convex lens 17, a dichroic mirror 16a, an IR-separating dichroic mirror 28a, and a convex lens 30.

[0023] The IR-separated illumination system of the light source device 10a consists of an IR-separated dichroic mirror 28a and a heat sink 29.

[0024] The time-series integrator illumination system of the light source device 10a consists of a color wheel 31a and a rod integrator 32.

[0025] First, the excitation light optics of the light source device 10a will be described. The blue wavelength excitation light emitted from each of the multiple laser diode light sources 11 is collimated by multiple collimator lenses 12, each of which is provided in relation to each of the multiple laser diode light sources 11. The collimated blue light is incident on a subsequent convex lens 13 to reduce its beam width, and is then incident on a subsequent diffuser plate 14 to diffuse it, improving the uniformity of the light. The blue light that has been incident on the diffuser plate 14 and diffused is then incident on a subsequent concave lens 15 to be made into a parallel beam. The blue light made into a parallel beam by the concave lens 15 is then incident on a dichroic mirror 16a, which is positioned at an angle of approximately 45 degrees with respect to the optical axis.

[0026] The dichroic mirror 16a reflects excitation light in the blue wavelength range from the laser diode light source 11 and transmits fluorescence emitted by the phosphor wheel 19a, which will be described later, after wavelength conversion of the excitation light from the laser diode light source 11.

[0027] Light from the laser diode light source 11, incident on the dichroic mirror 16a, changes its direction of propagation by 90 degrees and is incident on the convex lens 17. The light from the laser diode light source 11, incident on the convex lens 17, is focused by the optical system of the convex lens 17 and the subsequent convex lens 18, and is concentrated onto the phosphor layer on the phosphor wheel 19a.

[0028] Next, the phosphor wheel 19a will be described with reference to Figures 2 to 3B. Figure 2 is a front view showing an example of the configuration of the phosphor wheel 19a according to Embodiment 1.

[0029] The phosphor wheel 19a is composed of a substrate 100a to which the motor 106 is attached, a plurality of phosphor layers, a reflective layer 104, and an opening 105.

[0030] The reflective layer 104 is provided on one side of the substrate 100a in an annular shape at the same distance from the pivot center of the substrate 100a. However, two openings 105 are provided in a part of the annular shape. Therefore, more precisely, the reflective layer 104 is provided in a substantially fan shape that forms a part of the annular shape.

[0031] On the reflective layer 104, phosphor layers are provided in divided regions. In the example shown in Figure 2, three types of phosphor layers 101, 102, and 103 are provided on the reflective layer 104. The multiple phosphor layers are arranged in a roughly fan-shaped form that forms part of a ring, similar to the reflective layer 104.

[0032] The substrate 100a may be made of a material such as aluminum, which has excellent heat dissipation properties. The substrate 100a is not limited to aluminum and may be made of other metals. Furthermore, the substrate 100a may be a transmissive substrate such as glass or sapphire, or a transmissive substrate such as glass or sapphire with a reflective region provided. In the case of a transmissive substrate 100a, the substrate itself may be configured to transmit light without providing any openings.

[0033] The phosphor layer 101 is a mixed layer in which a phosphor that emits yellow fluorescence, excited and wavelength-converted by blue light from the laser diode light source 11, is filled into a heat-resistant resin such as silicone or silsesquioxane. Specific examples of phosphors include yttrium (Y) and aluminum (Al) composite oxide phosphors, YAG, and Y ３ Al ５ O １２ These are some examples.

[0034] The phosphor layer 102 is a mixed layer provided on top of the phosphor layer 101, in which a phosphor that is excited by light in the green wavelength range of the yellow fluorescence converted in the phosphor layer 101 and emits infrared fluorescence is filled into a heat-resistant resin such as silicone or silsesquioxane. A specific example of a phosphor is Cr ３＋ Examples include composite oxide phosphors.

[0035] The phosphor layer 103 is a mixed layer in which a phosphor that emits green fluorescence, excited by blue light from the laser diode light source 11 and wavelength-converted, is filled into a heat-resistant resin such as silicone or silsesquioxane. Specific examples of phosphors include ruthenium (Lu) and aluminum (Al) composite oxide phosphors, LuAG, and Lu ３ AL ５ O １２ These are some examples.

[0036] The phosphor layers 101, 102, and 103 may be composed of sintered phosphor particles forming a part of a ring shape, or they may be a combination of sintered particles and mixed layers.

[0037] In the description here, an example where the phosphor layer 102 is excited by light in the green wavelength range has been described. However, the present invention is not limited to this, and the phosphor layer 102 may be excited by light in other wavelength ranges such as red light. Further, although a configuration in which the phosphor layer 102 is provided on the phosphor layer 101 has been illustrated, the present invention is not limited to this. As shown in Modification 1 described later, a phosphor layer that is excited by green light or red light among the fluorescence wavelength-converted by the phosphor layer 101 and emits infrared fluorescence may be provided under the phosphor layer 101. Further, a phosphor layer capable of emitting infrared fluorescence may be provided on both the phosphor layer 101 and the phosphor layer 103.

[0038] Hereinafter, a phosphor layer that is excited by light in a specific wavelength range among the fluorescence wavelength-converted by another phosphor layer such as the phosphor layer 102 and emits fluorescence in the infrared wavelength range may be referred to as a second phosphor layer. And, for example, under the second phosphor layer, in other words, on the substrate 100a side, a phosphor layer that is excited by excitation light corresponding to the other phosphor layer and emits fluorescence in a different wavelength range may be referred to as a first phosphor layer. The first phosphor layer may be, for example, the phosphor layer 101 or the like. <(

[0039] Further, the phosphor layer 102 may be a mixed layer in which phosphors contained in the phosphor layer 101 and phosphors contained in the phosphor layer 102 are mixed and filled in a heat-resistant resin such as silicone or silsesquioxane.

[0040] The infrared light wavelength-converted and emitted by the phosphor layer 102 is converted into heat and is not used as the emitted light of the light source device 10a. Since the temperature of the phosphor layer increases as the thickness of the phosphor layer increases, it is desirable that the thickness of the phosphor layer 102 is thinner than the thickness of the phosphor layer 101.

[0041] The reflective layer 104 is, for example, a mixed layer in which heat-resistant resin such as silicone or silsesquioxane is filled with high-reflectivity particles. The particles filled in the reflective layer 104 are not limited to high-reflectivity particles, and high thermal conductivity particles may also be filled. The reflective layer 104 may be a mixed layer in which not only the reflectivity but also the thermal conductivity is improved.

[0042] The plurality of phosphor layers, the reflective layer 104, and the opening 105 are arranged so as to form an annulus at the same distance (on the same radius) from the rotation center of the substrate 100a of the phosphor wheel 19a. In FIG. 2, an example of an arrangement in which there are two opening portions 105 and a plurality of phosphor layers respectively forming a pair is illustrated, but the arrangement is not limited thereto. Further, in FIG. 2, an example in which the angles between the paired opening portions 105 and the phosphor layers are the same (for example, the angles between the opening portion 105 and the phosphor layer 103 are the same for each of the two) is illustrated, but they may be different angles.

[0043] The light from the laser diode light source 11 guided by the excitation light optical system is condensed in the regions of the opening 105 and the plurality of phosphor layers formed on the same radius from the rotation center of the phosphor wheel 19a. Since the phosphor wheel 19a is rotating, the light guided to the phosphor wheel 19a is condensed in the opening 105 and the plurality of phosphor layers in order. Hereinafter, the behavior of light in the opening 105 and the plurality of phosphor layers will be described.

[0044] First, the light from the laser diode light source 11 condensed in the opening 105 passes through the opening 105 as it is and is guided to the blue loop optical system. The behavior of light in the blue loop optical system will be described later.

[0045] Next, the behavior of the light condensed in the phosphor layer 102 will be described with reference to FIG. 3A. FIG. 3A is a cross-sectional view showing the AA cross-section of the phosphor wheel 19a according to Embodiment 1.

[0046] As shown in FIG. 3A, the phosphor layer 101 and the phosphor layer 102 are formed on the reflective layer 104 formed on the surface of the substrate 100a. As described above, it is desirable that the thickness t2 of the phosphor layer 102 is thinner than the thickness t1 of the phosphor layer 101.

[0047] Light from the laser diode light source 11 first enters the phosphor layer 102. It is desirable that the phosphor layer 102 is not excited by the light from the laser diode light source 11, but this does not exclude the case in which the phosphor layer 102 is excited by the light from the laser diode light source 11. In other words, the light from the laser diode light source 11 passes directly through the phosphor layer 102 and enters the phosphor layer 101. The light from the laser diode light source 11 that enters the phosphor layer 101 is wavelength-converted and emitted as yellow fluorescence, which is a mixture of green and red light. Due to complete diffusion, the wavelength-converted yellow fluorescence is emitted both on the substrate 100a side and on the phosphor layer 102 side.

[0048] Of the light from the laser diode light source 11, the light that is not wavelength-converted by either the phosphor layer 101 or the phosphor layer 102, and the fluorescence that is wavelength-converted by the phosphor layer 101 and emitted towards the substrate 100a, are reflected by the reflective layer 104, change direction of propagation, and emitted towards the phosphor layer 101.

[0049] Light from the laser diode light source 11, reflected by the reflective layer 104, is wavelength-converted by the phosphor layer 101 and emitted as yellow fluorescence, which is a mixture of green and red light. Due to complete diffusion, the fluorescence is emitted both towards the substrate 100a and the phosphor layer 102. Of this fluorescence, the fluorescence emitted towards the substrate 100a is reflected back to the phosphor layer 101, so the following explanation will focus on the light from the laser diode light source 11 and the fluorescence emitted towards the phosphor layer 102.

[0050] The phosphor layer 102 is excited by green light from fluorescence and has the property of wavelength-converting green light to infrared light. Therefore, light from the laser diode light source 11 emitted from the phosphor layer 101 that has not undergone wavelength conversion passes directly through the phosphor layer 102. Similarly, light in the red wavelength range from fluorescence emitted from the phosphor layer 101 also passes directly through the phosphor layer 102. Light in the green wavelength range from fluorescence emitted from the phosphor layer 101 is wavelength-converted to infrared light. The fluorescence wavelength-converted in the phosphor layer 102 is emitted towards the substrate 100a side due to complete diffusion, but passes through the phosphor layer 101 without wavelength conversion, is reflected by the reflective layer 104, and then transmits back through the phosphor layer 101. As a result, the fluorescence wavelength-converted in the phosphor layer 102 is emitted from the phosphor layer 102 towards the surface (positive z-axis direction). The behavior of light from the laser diode light source 11 that has not been wavelength-converted after being emitted from the phosphor layer 102, the infrared and red light that has been transmitted directly through the phosphor layer 102, and the green light that has not been wavelength-converted by the phosphor layer 102 will be described later in the explanation of the fluorescent illumination system.

[0051] Next, the behavior of the light focused on the phosphor layer 101 will be explained with reference to Figure 3B. Figure 3B is a cross-sectional view showing the BB cross section of the phosphor wheel 19a according to Embodiment 1.

[0052] A reflective layer 104 is formed on the substrate 100a, and a phosphor layer 101 is formed on the reflective layer 104.

[0053] Light from the laser diode light source 11 first enters the phosphor layer 101 from the positive z-axis direction. The phosphor layer 101 is excited by the light from the laser diode light source 11 and emits yellow fluorescence containing green and red light, which are wavelength-converted from the light from the laser diode light source 11. Due to complete diffusion, the wavelength-converted yellow fluorescence is emitted on both the substrate 100a side and the surface side (positive z-axis direction).

[0054] Light from the laser diode light source 11 that has not undergone wavelength conversion and fluorescence that has undergone wavelength conversion by the phosphor layer 101 and is emitted towards the substrate 100a are reflected by the reflective layer 104 formed between the substrate 100a and the phosphor layer 101, changing their direction of propagation and being emitted towards the phosphor layer 101 (positive z-axis direction).

[0055] Of the light from the laser diode light source 11 reflected by the reflective layer 104, some passes through the phosphor layer 101 without wavelength conversion, while the remainder is wavelength converted in the phosphor layer 101 and emitted from the phosphor layer 101 as yellow fluorescence containing green and red. Due to complete diffusion, some fluorescence is also emitted towards the reflective layer 104, but as explained with reference to Figure 3A, it is emitted again towards the phosphor layer 101. The subsequent behavior is the same as explained with reference to Figure 3A, so the explanation will be omitted. Fluorescence incident on the phosphor layer 101 passes through it and is emitted from the surface of the phosphor layer 101. The subsequent behavior will be described later, along with the fluorescence emitted from the phosphor layer 102.

[0056] The structure and behavior of the phosphor layer 103 are the same as those of the phosphor layer 101, except that it converts the light from the laser diode light source 11 into green fluorescence; therefore, a detailed explanation will be omitted.

[0057] Returning to Figure 1, we will now explain the behavior of light in the blue loop optical system after it has passed through the aperture 105 of the phosphor wheel 19a.

[0058] The blue loop optical system consists of a relay optical system comprising two convex lenses (convex lens 20, convex lens 21) immediately behind the phosphor wheel 19a, three total reflection mirrors (total reflection mirror 22, total reflection mirror 24, total reflection mirror 26) and three convex lenses (convex lens 23, convex lens 25, convex lens 27), a dichroic mirror 16a shared with the excitation light optical system described above, an IR separation dichroic mirror 28a, and a convex lens 30.

[0059] Light from the laser diode light source 11 that has passed through the aperture 105 of the phosphor wheel 19a is made into parallel light by passing through two convex lenses (convex lens 20, convex lens 21) immediately after the phosphor wheel 19a. The parallelized light has its direction of propagation changed by a relay optical system consisting of three total reflection mirrors and three convex lenses, and is incident on the dichroic mirror 16a from a direction 180 degrees opposite to the direction in which the light from the laser diode light source 11 enters the excitation light optical system, specifically from the negative x-axis direction.

[0060] As described above, the dichroic mirror 16a has the characteristic of reflecting blue wavelength light from the laser diode light source 11 and transmitting fluorescence from the phosphor wheel 19a. Therefore, the light from the laser diode light source 11 that has passed through the opening 105 of the phosphor wheel 19a is reflected by the dichroic mirror 16a and changes its direction of travel toward the direction of the IR separation dichroic mirror 28a (positive z-axis direction).

[0061] The IR-separated dichroic mirror 28a has the characteristic of reflecting light in the infrared wavelength range and transmitting other light from the fluorescence excited and wavelength-converted by light from the laser diode light source 11 in the phosphor wheel 19a. Specifically, the light other than the infrared wavelength range is blue light, green light, and red light. The blue light is, for example, the light from the laser diode light source 11. The red light is, for example, the light in the red wavelength range from the fluorescence excited and wavelength-converted by light from the laser diode light source 11 in the phosphor wheel 19a.

[0062] Light from the laser diode light source 11, after passing through the IR-separated dichroic mirror 28a, passes through the subsequent convex lens 30 and is focused onto the color wheel 31a.

[0063] The behavior of light from the laser diode light source 11 after it is incident on the color wheel 31a will be described later in the explanation of the time-series integrator illumination system.

[0064] Next, the behavior of fluorescence emitted after wavelength conversion, which is excited by light from the laser diode light source 11 when light is incident on the phosphor layer of the phosphor wheel 19a in a fluorescent lighting system, will be explained with reference to Figure 1.

[0065] The fluorescent illumination system consists of two convex lenses (convex lens 18 and convex lens 17) directly in front of the phosphor wheel 19a, a dichroic mirror 16a, an IR-separating dichroic mirror 28a, and a convex lens 30. The fluorescent illumination system shares the two convex lenses directly in front of the phosphor wheel 19a and the dichroic mirror 16a as the excitation light optical system, and the dichroic mirror 16a, the IR-separating dichroic mirror 28a, and the convex lens 30 as the blue loop optical system.

[0066] From the phosphor layers 101, 102, and 103 on the phosphor wheel 19a, yellow (green and red) fluorescence and light from the laser diode light source 11 that has not been wavelength-converted, yellow (green and red) and infrared fluorescence and light from the laser diode light source 11 that has not been wavelength-converted, and green fluorescence and light from the laser diode light source 11 that has not been wavelength-converted are emitted in a time series, respectively. The light emitted from the phosphor wheel 19a is incident on two convex lenses (convex lens 18, convex lens 17) and is made into parallel light. The parallelized light is then incident on the dichroic mirror 16a.

[0067] The dichroic mirror 16a reflects blue wavelength light from the laser diode light source 11 and transmits the fluorescence excited by the light from the laser diode light source 11 and the fluorescence that has been wavelength-converted by the phosphor wheel 19a. Therefore, of the fluorescence emitted from the phosphor wheel 19a and the light from the laser diode light source 11 that has not been wavelength-converted, only the fluorescence passes through the dichroic mirror 16a and proceeds to the IR separation dichroic mirror 28a.

[0068] As described above, the IR separation dichroic mirror 28a has the characteristic of reflecting light in the infrared region of the wavelength-converted fluorescence emitted from the phosphor wheel 19a, and transmitting other light.

[0069] Therefore, of the fluorescence from the phosphor wheel 19a, the yellow fluorescence, including green and red light other than infrared light, passes through the IR-separated dichroic mirror 28a, then through the subsequent convex lens 30, and is focused onto the color wheel 31a. Considering the arrangement of each component, the IR-separated dichroic mirror 28a is located on the optical path extending from the phosphor wheel 19a to the color wheel 31a. Thus, the IR-separated dichroic mirror 28a branches off the infrared fluorescence from the optical path toward the color wheel 31a and guides it in a direction different from the optical path toward the color wheel 31a. In other words, the IR-separated dichroic mirror 28a guides the infrared fluorescence outside the optical path toward the color wheel 31a, that is, outside the blue loop optical system, the fluorescence illumination system, and the time-series integrator illumination system. As a result, it is possible to suppress the use of infrared fluorescence as the emitted light of the light source device 10a.

[0070] The fluorescence behavior after incidence onto the color wheel 31a will be described later in the explanation of the time-series integrator illumination system.

[0071] Next, regarding the behavior of light after it has been reflected and separated by the IR-separated dichroic mirror 28a in the fluorescent lighting system, or in other words, the behavior of light in the IR-separated lighting system, we will explain with reference to Figure 1.

[0072] The IR separation illumination system consists of an IR separation dichroic mirror 28a and a heat sink 29. Of the fluorescence from the phosphor wheel 19a, the infrared light reflected by the IR separation dichroic mirror 28a and separated is incident on the heat sink 29. The heat sink 29 may be provided with cooling means such as a cooling fan (not shown). As a result, the heat of the separated infrared light is cooled by the heat sink 29. Hereinafter, the IR separation dichroic mirror may be referred to as the light separation means.

[0073] Next, the behavior in the time-series integrator illumination system after light from the laser diode light source 11 from the blue loop optical system, i.e., blue light, and fluorescence from the fluorescent illumination system, i.e., green light and yellow light including green and red light, are incident on the color wheel 31a will be described with reference to Figures 1 and 4. Figure 4 is a front view showing an example of the configuration of the color wheel 31a according to Embodiment 1.

[0074] The time-series integrator illumination system consists of a color wheel 31a and a rod integrator 32.

[0075] The color wheel 31a is constructed by attaching a holding part 200 provided on the motor 206 to a transparent substrate 220 (see Figure 9), where multiple regions having predetermined properties are formed by, for example, applying a dielectric multilayer film to the surface of the transparent substrate 220 (see Figure 9). The transparent substrate 220 may be made of, for example, a glass plate or a sapphire substrate.

[0076] Each region of the color wheel 31a is configured in a roughly fan-shaped form. Region 201 has the property of transmitting light in the blue, green, and red wavelength ranges. Region 202 has the property of reflecting light in the red wavelength range and transmitting light in wavelength ranges other than the red wavelength range. Region 203 has the property of transmitting light in the blue, green, and red wavelength ranges. Region 204 has the property of reflecting light in the green wavelength range and transmitting light in wavelength ranges other than the green wavelength range.

[0077] A synchronization circuit (not shown) synchronizes the rotational positions of the color wheel 31a and the phosphor wheel 19a. Hereinafter, synchronization between the phosphor wheel and the color wheel is described as being able to rotate with a specific region of the phosphor wheel and a specific region of the color wheel facing each other. In other words, the phosphor wheel and the color wheel are adjusted so that the same phenomenon repeats regularly over time. Note that the "facing each other" state may include a predetermined corresponding positional relationship between a specific region of the phosphor wheel and a specific region of the color wheel, and is not limited to, for example, a state in which these specific regions almost completely overlap when viewed in the direction of the optical axis.

[0078] Furthermore, as an example, in the light source device or projection-type image display device related to this disclosure, a configuration may be adopted in which the color wheel rotates N times (N: a natural number) while the phosphor wheel rotates once, or in which the phosphor wheel rotates N times while the color wheel rotates once. Therefore, synchronization between the phosphor wheel and the color wheel may include the state of the phosphor wheel and the color wheel in these configurations (i.e., the color wheel rotates N times while the phosphor wheel rotates once, or the phosphor wheel rotates N times while the color wheel rotates once). Note that the relationship between the rotation speeds of the phosphor wheel and the color wheel is not limited to these.

[0079] The phosphor wheel 19a shown in Figure 2 and the color wheel 31a shown in Figure 4 are illustrated in synchronized positions. Hereafter, the phosphor wheel 19a shown in Figure 2 will be described as rotating clockwise, and the color wheel 31a shown in Figure 4 will be described as rotating counterclockwise.

[0080] In the color wheel 31a, regions 201 and a portion of region 202 are located at the position corresponding to the opening 105 of the phosphor wheel 19a. As described above, regions 201 and 202 of the color wheel 31a have the characteristic of transmitting light in the blue wavelength range. Therefore, the blue light from the laser diode light source 11 that passes through the opening 105 of the phosphor wheel 19a passes through the color wheel 31a as is and is incident on the rod integrator 32.

[0081] In the color wheel 31a, region 202 is located at the position corresponding to the phosphor layer 103 of the phosphor wheel 19a. As described above, region 202 of the color wheel 31a has the characteristic of reflecting light in the red wavelength range and transmitting light in wavelength ranges other than the red wavelength range. Therefore, the green light excited and wavelength-converted in the phosphor layer 103 is transmitted through the color wheel 31a as is.

[0082] In the color wheel 31a, regions 203 and 204 are located at positions corresponding to the phosphor layer 101 of the phosphor wheel 19a. As described above, region 203 of the color wheel 31a has the property of transmitting light in the respective wavelength ranges of blue, green, and red. Therefore, yellow light including green and red, which has been excited and wavelength-converted in the phosphor layer 101 and reached the region corresponding to region 203, is transmitted through the color wheel 31a as is.

[0083] Furthermore, as described above, region 204 of the color wheel 31a has the characteristic of reflecting light in the green wavelength range and transmitting light in wavelength ranges other than the green wavelength range. Therefore, the red light, which is the yellow light containing green and red that has been excited and wavelength-converted in the phosphor layer 101 and has had the green light removed, passes through the color wheel 31a.

[0084] In the color wheel 31a, region 204 is located at the position corresponding to the phosphor layer 102 of the phosphor wheel 19a. As described above, region 204 of the color wheel 31a has the characteristic of reflecting light in the green wavelength range and transmitting light in wavelength ranges other than the green wavelength range. Here, since phosphor layer 101 is formed below phosphor layer 102, green light, red light, and infrared light are emitted from phosphor layer 102 as fluorescence. Then, green light and red light, excluding the infrared light removed by the IR separation dichroic mirror 28a, reach the color wheel 31a. Therefore, in region 204, light in the green wavelength range is reflected and light in the red wavelength range is transmitted.

[0085] In this way, the light emitted from the color wheel 31a in a time series according to the positions of the phosphor wheel 19a and the color wheel 31a is incident on the rod integrator 32. The rod integrator 32 emits uniform light through multiple reflections within the rod integrator 32.

[0086] Furthermore, the green light reflected in region 204 of the color wheel 31a passes through the convex lens 30, the IR-separating dichroic mirror 28a, the dichroic mirror 16a, the convex lens 17, and the convex lens 18, and is focused onto the phosphor layer 102 of the phosphor wheel 19a. A portion of the focused green light is converted to infrared light, and the rest is absorbed, causing the temperature of the phosphor wheel 19a to rise. However, since the green light ultimately absorbed by the phosphor wheel 19a does not contain light in the infrared wavelength range that is removed by the IR separation means, the temperature rise of the phosphor wheel 19a is slower compared to a case where there is no wavelength conversion layer to convert green fluorescence to infrared light. Also, because the separated light is infrared light, separation by the IR-separating dichroic mirror 28a is possible without affecting the projected image. Furthermore, even if the excitation light and the combination of fluorescence converted from the excitation light by the phosphor differ from those in this embodiment, if the separated light is infrared light, it is possible to suppress the temperature rise of the phosphor wheel 19a with a similar configuration.

[0087] In the light source device 10a according to Embodiment 1, the phosphor layer 102 is excited by green light wavelength-converted by the phosphor layer 101 and emits infrared light wavelength-converted. The infrared light is guided to the heat sink 29 by the IR separation dichroic mirror 28a and converted into heat. As a result, the light source device 10a can suppress the temperature rise of the phosphor wheel 19a compared to a case where the phosphor layer 102 is not provided. Furthermore, since infrared light is invisible light, it is possible to suppress the temperature rise of the phosphor wheel 19a while avoiding affecting the projected light emitted from the light source device 10a (for example, deterioration of the quality of the projected image). As a result, the light source device 10a can suppress the occurrence of efficiency reduction and reliability problems.

[0088] As described above, the light source device according to this embodiment (for example, light source device 10a) includes a light source (for example, a laser diode light source 11), a wavelength conversion element (for example, a phosphor wheel 19a) that converts excitation light from the light source to light in different wavelength ranges, a wavelength selection element (for example, a color wheel 31a) that reflects light in a specific wavelength range from the light from the wavelength conversion element, and an optical separation means (for example, an IR separation dichroic mirror 28a) that is arranged on the optical path of the light from the wavelength conversion element and separates light in a specific wavelength range from the light from the wavelength conversion element. With this configuration, for example, even if the light reflected by the color wheel is focused on a wavelength conversion element such as a phosphor wheel, and the temperature of the wavelength conversion element rises, the temperature rise of the wavelength conversion element is suppressed compared to when the light in a specific wavelength range is not separated, because light in a specific wavelength range is separated from the light.

[0089] Furthermore, in the light source device according to this embodiment, the wavelength conversion element has a first phosphor layer (for example, phosphor layer 101) and a second phosphor layer (for example, phosphor layer 102), wherein the first phosphor layer is configured to include a first phosphor that wavelength-converts excitation light to fluorescence in a different wavelength range, and the second phosphor layer is configured to include a second phosphor that wavelength-converts light in a specific wavelength range from fluorescence to infrared light. With this configuration, for example, excitation light incident on the first phosphor layer of a wavelength conversion element such as a phosphor wheel is wavelength-converted. When the wavelength-converted fluorescence is incident on the second phosphor layer, light in a specific wavelength range from the fluorescence is wavelength-converted to infrared light and emitted from the second phosphor layer.

[0090] Furthermore, in the light source device according to this embodiment, the light separation means separates infrared light from the light from the wavelength conversion element. With this configuration, for example, when light from a wavelength conversion element such as a phosphor wheel is incident on a light separation means such as an IR separation dichroic mirror, the infrared wavelength range of the light can be separated by the light separation means.

[0091] Furthermore, in the light source device according to this embodiment, the second phosphor converts the green wavelength light of the fluorescence into infrared light. With this configuration, when excitation light from the light source is incident on the first phosphor layer and wavelength converted, and then incident on the second phosphor layer as fluorescence, the green wavelength light of the fluorescence can be converted into infrared light.

[0092] Furthermore, in the light source device according to this embodiment, the second phosphor layer is provided on the first phosphor layer and is arranged so that reflected light from the wavelength-selecting element is incident on it. With this configuration, the light emitted from the second phosphor layer has its infrared light separated along its optical path, and then is incident on the color wheel and reflected. The reflected light from the color wheel is then focused onto the second phosphor layer. Here, since the reflected light from the color wheel does not contain light in the infrared wavelength range, the temperature rise of the wavelength conversion element, such as the phosphor wheel including the second phosphor layer, due to the focus onto the second phosphor layer is suppressed.

[0093] Furthermore, in the light source device according to this embodiment, the thickness of the second phosphor layer (for example, thickness t2) is thinner than the thickness of the first phosphor layer (for example, thickness t1). With this configuration, the temperature rise of the second phosphor layer is suppressed, and consequently, the temperature rise of wavelength conversion elements such as phosphor wheels is suppressed.

[0094] Furthermore, as will be described in detail in Embodiment 3, by changing the relative position between the phosphor wheel and the color wheel, the ratio of red to green in the emitted light can be changed, making it possible to realize multiple color modes.

[0095] <Modification 1 of Embodiment 1> Figure 5 is a cross-sectional view showing a cross-section of the phosphor wheel 19a-0 according to Modification 1 of Embodiment 1. The phosphor wheel 19a-0 according to Modification 1 of Embodiment 1 differs from the phosphor wheel 19a according to Embodiment 1 in the arrangement of the phosphor layers 101 and 102, but is otherwise common to the original configuration. The explanation will focus on the changes from the phosphor wheel 19a according to Embodiment 1. Note that the phosphor wheel 19a-0 may be applied in place of a phosphor wheel in other embodiments and modifications in which the phosphor layer 102 is provided on top of the phosphor layer 101.

[0096] As shown in Figure 5, the phosphor layer 102 is provided below the phosphor layer 101. Specifically, the phosphor layer 102 is provided between the phosphor layer 101 and the reflective layer 104. That is, the phosphor layer 101 is the uppermost layer that forms the surface. In modification 1 of Embodiment 1, the phosphor layer 102 is in contact with the phosphor layer 101 and the reflective layer 104.

[0097] In the manufacture of the phosphor wheel 19a-0, the phosphor layer 102 and the phosphor layer 101 may be laminated in order on the reflective layer 104.

[0098] The following describes the behavior of light in multiple phosphor layers.

[0099] Light from the laser diode light source 11 first enters the phosphor layer 101 from the positive z-axis direction. The light from the laser diode light source 11 that enters the phosphor layer 101 is wavelength-converted and emitted from the phosphor layer 101 as yellow fluorescence containing green and red. Due to complete diffusion, the wavelength-converted yellow fluorescence is emitted on both the substrate 100a side and the surface side (positive z-axis direction).

[0100] The fluorescence emitted from the substrate 100a then enters the phosphor layer 102. Of the fluorescence that enters the phosphor layer 102, the green light is wavelength-converted and emitted from the phosphor layer 102 as infrared light. On the other hand, the red light of the fluorescence that enters the phosphor layer 102 passes straight through the phosphor layer 102, is reflected by the reflective layer 104, changes direction of propagation, passes through the phosphor layers 102 and 101, and is emitted from the phosphor layer 101 towards the surface (positive z-axis direction).

[0101] Infrared light emitted from the phosphor layer 102 is emitted on both the substrate 100a side and the surface side (positive z-axis direction) due to complete diffusion. Infrared light emitted on the surface side passes through the phosphor layer 101 and is emitted from the phosphor layer 101 to the surface (positive z-axis direction). Fluorescence that has been wavelength-converted by the phosphor layer 102 and emitted on the substrate 100a side is reflected by the reflective layer 104, changes direction of propagation, passes through the phosphor layers 102 and 101, and is emitted from the phosphor layer 101 to the surface (positive z-axis direction). Note that the phosphor layer 101 is not easily excited by infrared light and is not excited by infrared light.

[0102] Furthermore, the yellow light that is wavelength-converted by the phosphor layer 101 and emitted to the surface is emitted from the phosphor layer 101 to the surface (positive z-direction). In addition, light that is not wavelength-converted by either the phosphor layer 101 or the phosphor layer 102 may be reflected by the reflective layer 104, transmitted through the phosphor layers 102 and 101, and emitted from the phosphor layer 101 to the surface (positive z-direction), or it may be wavelength-converted when it is re-incident to the phosphor layer 101.

[0103] As described above, green light, red light, and infrared light are emitted as fluorescence from the phosphor layer 102 and the phosphor layer 101 above it. Green light and red light, excluding the infrared light removed by the IR separation dichroic mirror 28a, reach the corresponding region 204 of the color wheel 31a. As described above, region 204 has the characteristic of reflecting green light and transmitting light in wavelength ranges other than the green wavelength range (for example, red light). The reflected green light returns to the phosphor wheel 19a-0, enters and is transmitted through the phosphor layer 101 above the phosphor layer 102, and excites the phosphor layer 102. The excited phosphor layer 102 emits infrared light, which is removed by the IR separation dichroic mirror 28a.

[0104] By placing the phosphor layer 101 on top of the phosphor layer 102, the excitation light from the laser diode light source 11 reaches the phosphor layer 101 first. Compared to the case where the phosphor layer 102 is placed on top of the phosphor layer 101, the excitation of the phosphor layer 102 by the excitation light from the laser diode light source 11 can be suppressed. As a result, more excitation light reaches the phosphor layer 101 and undergoes wavelength conversion there. Consequently, the wavelength conversion efficiency of the excitation light in the phosphor wheel 19a-0 is improved.

[0105] Furthermore, similar to the phosphor wheel 19a according to Embodiment 1, it is desirable that the thickness t2 of the phosphor layer 102 is thinner than the thickness t1 of the phosphor layer 101. This configuration makes it possible to suppress the temperature rise of the phosphor layer 102.

[0106] The phosphor layer 102 in the modified example 1 of Embodiment 1 converts green light to infrared light, but is not limited to this. The phosphor layer 102 may also convert the red light from the yellow fluorescence converted by the phosphor layer 101 to infrared light. The phosphor layer 102 is a layer that converts light in a specific wavelength range from the fluorescence converted by the phosphor layer 101 to light in a second wavelength range different from the first wavelength range.

[0107] <Modification 2 of Embodiment 1> Figure 6 is a schematic diagram showing an example of the configuration of a light source device 10a-1 according to Modification 2 of Embodiment 1. In the light source device 10a-1 according to Modification 2 of Embodiment 1, the position of the heat sink 29 and the configuration of the phosphor wheel and color wheel are different from those of the light source device 10a according to Embodiment 1. There are no other changes, so we will explain by focusing on the changes.

[0108] Figure 7 is a front view showing an example configuration of a phosphor wheel 19a-1 according to a modification 2 of Embodiment 1. The phosphor wheel 19a-1 differs from the phosphor wheel 19a shown in Figure 2 in that the phosphor layer 102 on the phosphor layer 101, which was provided in the phosphor wheel 19a-1, is not provided in the phosphor wheel 19a-1. Therefore, the excitation light from the laser diode light source 11 causes yellow (green and red) light, whose wavelength has been converted by the phosphor layer 101, and green light, whose wavelength has been converted by the phosphor layer 103, to be emitted from the phosphor wheel 19a-1 in a time series. Note that the phosphor wheel 19a-1 shown in Figure 7 rotates clockwise in the same way as the phosphor wheel 19a shown in Figure 2.

[0109] Figure 8 is a front view showing an example of the configuration of a color wheel 31a-1 according to modification 2 of Embodiment 1. Figure 9 is a cross-sectional view showing the CC cross section of the color wheel 31a-1 according to modification 2 of Embodiment 1. The difference between the color wheel 31a-1 and the color wheel 31a shown in Figure 4 is that a region 205 with only different reflection characteristics is provided at a position corresponding to region 204 of the color wheel 31a, and a phosphor layer 210 is provided in the region through which the incident light from the convex lens 30 passes, as shown in the cross-sectional view in Figure 9.

[0110] Region 205 transmits red light and reflects blue, green, and infrared light, whereas region 204 transmits red light and reflects blue and green light. Region 205 is synchronized to the position corresponding to the phosphor layer 101 of the phosphor wheel 19a-1.

[0111] The phosphor layer 210 has the characteristic of converting the green light from the yellow (green and red) light, which is excited by the excitation light from the laser diode light source 11 and wavelength-converted by the phosphor layer 101 on the phosphor wheel 19a-1, into infrared light.

[0112] The behavior of green and red (i.e., yellow) light from the phosphor layer 101 of the phosphor wheel 19a-1, emitted from the convex lens 30 and incident on the phosphor layer 210 of the color wheel 31a-1, will be described in detail below with reference to Figure 9.

[0113] Of the yellow fluorescence incident on the phosphor layer 210 from the negative z-axis direction, the red light passes through the phosphor layer 210, then through the region 205 which has the characteristic of transmitting red light as described above, then through the transparent substrate 220, and is incident on the subsequent rod integrator 32.

[0114] Of the yellow fluorescence incident on the phosphor layer 210 from the negative z-axis direction, the green light is wavelength-converted to infrared fluorescence in the phosphor layer 210. The green light that is not wavelength-converted in the phosphor layer 210 is reflected by region 205, and a portion of it is further wavelength-converted to infrared light in the phosphor layer 210. The infrared light generated by the wavelength conversion is emitted towards region 205 due to complete diffusion, but since region 205 has the property of reflecting infrared light, its direction of propagation is changed by 180 degrees. Therefore, the phosphor layer 210 emits both infrared light generated by the wavelength conversion of green light and the green light that remains unconverted.

[0115] The behavior of infrared and green light emitted from the phosphor layer 210 of the color wheel 31a-1 will be described below. The infrared and green light emitted from the phosphor layer 210 are incident on the convex lens 30, parallelized, and then incident on the IR-separated dichroic mirror 28a. As mentioned above, the IR-separated dichroic mirror 28a has the characteristic of reflecting infrared light and transmitting blue, green, and red light. Therefore, the infrared light changes its direction of propagation by 90 degrees and is incident on the heat sink 29, where it is heat-treated.

[0116] Green light that was not wavelength-converted in the phosphor layer 210 passes through the IR separation dichroic mirror 28a, then sequentially through the dichroic mirror 16a, the convex lens 17, and the convex lens 18, before reaching the phosphor wheel 19a-1.

[0117] In this embodiment, a portion of the light emitted from the color wheel 31a-1 to the phosphor wheel 19a-1 is heat-treated by the heat sink 29, thereby suppressing the temperature rise of the phosphor wheel 19a-1.

[0118] Next, in this embodiment, by shifting the phase of the color wheel 31a-1 relative to the phosphor wheel 19a-1, the proportion of colors contained in the light emitted from the light source device 10a-1 can be changed, thereby enabling the light source device 10a-1 to have multiple color modes. Hereafter, the change in the proportion of colors will be explained using the color wheel 31a-1 shown in Figure 8 and the color wheel 31a-1 shown in Figure 11, which is shifted in phase by 22.5 degrees relative to the phosphor wheel 19a-1. For the sake of ease of explanation, the angles (central angles) of the opening 105 of the phosphor wheel 19a-1, each phosphor layer, each region of the color wheel 31a-1, and each phosphor layer with respect to the wheel center are shown as multiples of 22.5 degrees, but in practice, they do not need to be multiples of 22.5 degrees.

[0119] In the combination of the phosphor wheel 19a-1 shown in Figure 7 and the color wheel 31a-1 shown in Figure 8, light is emitted in the sequence shown in Figure 10, and the proportion of each color is as shown in Table 1 below. Figure 10 is a schematic diagram showing the time-series light emission sequence of the light source device 10a-1 according to Modification 2 of Embodiment 1. Here, "B" represents blue, "R" represents red, "Ye" represents yellow, and "G" represents green.

[0120]

[0121] Figure 11 is a front view showing an example of the configuration of a color wheel 31a-1 according to a modification 2 of Embodiment 1. The color wheel 31a-1 shown in Figure 11 is in a state where its phase is shifted by 22.5 degrees from the state shown in Figure 8 relative to the phosphor wheel 19a-1.

[0122] In the combination of the phosphor wheel 19a-1 shown in Figure 7 and the color wheel 31a-1 shown in Figure 11, light is emitted in the sequence shown in Figure 12, and the proportion of each color is as shown in Table 2 below. Figure 12 is a schematic diagram showing the time-series light emission sequence of the light source device 10a-1 according to a modified example 2 of Embodiment 1.

[0123]

[0124] As shown in Table 1, when the phase of the color wheel 31a-1 is as shown in Figure 8, more red light is emitted, and as shown in Table 2, when the phase of the color wheel 31a-1 is as shown in Figure 11, more green light is emitted. In this way, the color mode of the light source device 10a-1 can be easily changed by changing the phase of the color wheel 31a-1. Thus, the phosphor wheel 19a-1 and the color wheel 31a-1 can be rotated in multiple (two in the modified example 2 of Embodiment 1) different relative phases.

[0125] In summary, in the modified example 2 of Embodiment 1, it is possible to suppress the temperature rise of the phosphor wheel 19a-1 and to realize multiple color modes simultaneously.

[0126] Conventionally, switching between multiple color modes has the problem that the temperature of at least a portion of the phosphor wheel rises depending on the selected color mode. This is because the reflected light from the color wheel to the phosphor wheel is, for example, green light or red light, depending on the selected color mode, and furthermore, this reflected light is absorbed by at least a portion of the phosphor wheel. Therefore, by using a configuration that can separate light in a specific wavelength range (e.g., infrared light) from the reflected light from the color wheel, as in this configuration, it becomes possible to suppress the temperature rise of the phosphor wheel and realize multiple color modes at the same time.

[0127] <Modification 3 of Embodiment 1> Figure 13 is a schematic diagram showing an example of the configuration of a light source device 10a-2 according to Modification 3 of Embodiment 1. The light source device 10a-2 has a configuration that combines the features of both the light source device 10a according to Embodiment 1 and the light source device 10a-1 according to Modification 2 of Embodiment 1, and a detailed explanation will be omitted as it would be redundant.

[0128] The light source device 10a-2 according to the third modification of Embodiment 1 suppresses the temperature rise in the phosphor wheel 19a-1 more effectively than Embodiment 1 and the second modification of Embodiment 1 by heat-treating the infrared light with two heat sinks 29, and also enables easy switching between multiple color modes.

[0129] <Embodiment 2> Figure 14 is a schematic diagram showing an example of the configuration of the light source device 10b according to Embodiment 2.

[0130] In the configuration example shown in Figure 14, the components are the same as those in the configuration example shown in Figure 1. However, in Embodiment 1, the IR-separating dichroic mirror 28a and the heat sink 29 were arranged between the dichroic mirror 16a and the convex lens 30 directly in front of the rod integrator 32. In contrast, in Embodiment 2, the IR-separating dichroic mirror 28b and the heat sink 29 are arranged between the concave lens 15 of the excitation light optical system and the dichroic mirror 16b. The light source device 10b includes an optical system in which light emitted from the laser diode light source 11 loops, and is configured to emit light of different wavelength ranges such as blue, green, and red in a time series. The light source device 10b is a light source device suitable for projection-type image display devices using a single-board DMD, which will be described later.

[0131] Furthermore, the IR-separated dichroic mirror 28b is similar to the IR-separated dichroic mirror 28a in the following respects. That is, the IR-separated dichroic mirror 28b transmits light in the blue wavelength range, which is light from the laser diode light source 11. Also, the IR-separated dichroic mirror 28b has the characteristic of reflecting infrared light that has been excited and wavelength-converted in the phosphor layer 102 of the phosphor wheel 19a. However, the IR-separated dichroic mirror 28b differs from the IR-separated dichroic mirror 28a in that its characteristics for light in wavelength ranges other than both the blue wavelength range and the infrared wavelength range, specifically green wavelength range light and red wavelength range light, are not limited to either transmission or reflection.

[0132] Furthermore, the dichroic mirror 16b is similar to the dichroic mirror 16a in that it reflects blue wavelength light from the laser diode light source 11 and transmits green and red wavelength light from the fluorescence emitted from the phosphor wheel 19a. However, the dichroic mirror 16b differs from the dichroic mirror 16a in that it has the characteristic of reflecting infrared wavelength light from the fluorescence emitted from the phosphor wheel 19a.

[0133] In the following description of Embodiment 2, we will explain the differences from Embodiment 1, and may omit detailed explanations of overlapping parts.

[0134] The excitation light optical system of the light source device 10b consists of a plurality of laser diode light sources 11, a plurality of collimator lenses 12, a convex lens 13, a diffuser plate 14, a concave lens 15, an IR separation dichroic mirror 28b, a dichroic mirror 16b, a convex lens 17, and a convex lens 18.

[0135] The process from the emission of blue wavelength light from the laser diode light source 11 to the emission of light from the concave lens 15 is the same as in Embodiment 1, so the explanation is omitted here.

[0136] The light, which has been parallelized by the concave lens 15, is incident on the IR-separating dichroic mirror 28b, which is positioned at an angle of approximately 45 degrees with respect to the optical axis. The IR-separating dichroic mirror 28b has the characteristic of transmitting light in the blue wavelength range, which is light from the laser diode light source 11. Therefore, the IR-separating dichroic mirror 28b transmits the light from the laser diode light source 11 as is.

[0137] Light from the laser diode light source 11, having passed through the IR-separated dichroic mirror 28b, is incident on a dichroic mirror 16b, which is positioned at an angle of approximately 45 degrees with respect to the optical axis. The dichroic mirror 16b has the characteristic of reflecting light in the blue wavelength range, which is light from the laser diode light source 11. Therefore, the light from the laser diode light source 11 changes its direction of travel by 90 degrees and is incident on the subsequent convex lens 17. The behavior of the light after it is incident on the convex lens 17 is the same as in Embodiment 1, so a detailed explanation is omitted here.

[0138] In the phosphor wheel 19a, similar to Embodiment 1, light in each wavelength range is emitted from the opening 105, the phosphor layer 101, the phosphor layer 103, and the layer in which the phosphor layer 101 and the phosphor layer 102 are stacked.

[0139] The blue loop optical system after light from the laser diode light source 11 passes through the aperture 105 of the phosphor wheel 19a will be described. The blue loop optical system of light source device 10a included an IR-separated dichroic mirror 28a. On the other hand, the blue loop optical system of light source device 10b does not include an IR-separated dichroic mirror 28b. Furthermore, the dichroic mirror 16b of light source device 10b has the characteristic of reflecting blue wavelength light from the laser diode light source 11, transmitting green and red light from the fluorescence emitted from the phosphor wheel 19a, and reflecting infrared light.

[0140] Light passing through the aperture 105 of the phosphor wheel 19a is parallelized by two convex lenses (convex lens 20, convex lens 21). The parallelized light then changes direction in a relay optical system consisting of three total reflection mirrors (total reflection mirror 22, total reflection mirror 24, total reflection mirror 26) and three convex lenses (convex lens 23, convex lens 25, convex lens 27), and enters the dichroic mirror 16b from a direction 180 degrees opposite to the direction in which light enters from the laser diode light source 11 in the excitation light optical system, specifically from the negative x-axis direction.

[0141] As described above, the dichroic mirror 16b has the characteristic of reflecting light in the blue wavelength range, which is light from the laser diode light source 11. Therefore, light incident on the dichroic mirror 16b is reflected, changes its direction of propagation by 90 degrees, passes through the convex lens 30, and is focused onto the color wheel 31a.

[0142] Next, the fluorescent illumination system of the light source device 10b will be described. The fluorescent illumination system of the light source device 10b differs from the fluorescent illumination system of the light source device 10a according to Embodiment 1 in the following two points. That is, the fluorescent illumination system of the light source device 10a includes an IR-separated dichroic mirror 28a, but the fluorescent illumination system of the light source device 10b does not include an IR-separated dichroic mirror 28b. Also, the characteristics of the dichroic mirror 16b differ from those of the dichroic mirror 16a.

[0143] The green fluorescence and yellow (green and red) fluorescence emitted after wavelength conversion in the respective regions of phosphor layer 101 and phosphor layer 103 are parallelized by passing through convex lenses 18 and 17 and incident on the dichroic mirror 16b. The dichroic mirror 16b has the characteristic of transmitting green and red light and reflecting infrared light from the fluorescence emitted from the phosphor wheel 19a. Therefore, the green fluorescence and yellow (green and red) fluorescence pass directly through the dichroic mirror 16b, incident on the subsequent convex lens 30, and are further focused on the subsequent color wheel 31a.

[0144] As described in Embodiment 1, the phosphor layer 102 is laminated on top of the phosphor layer 101, and therefore emits yellow (green and red) fluorescence and infrared fluorescence. The fluorescence emitted from the phosphor layer 102 is parallelized by passing through the convex lens 18 and the convex lens 17 and incident on the dichroic mirror 16b. The dichroic mirror 16b has the characteristic of transmitting green and red light from the fluorescence emitted from the phosphor wheel 19a and reflecting infrared light. Therefore, of the fluorescence emitted from the phosphor layer 102 and incident on the dichroic mirror 16b, the yellow (green and red) fluorescence passes through as is, but the infrared light is reflected and its direction of propagation is changed by 90 degrees towards the laser diode light source 11 (positive x-axis direction). The yellow fluorescence that has passed through the dichroic mirror 16b is incident on the subsequent convex lens 30 and further focused on the subsequent color wheel 31a. The behavior of infrared light reflected by the dichroic mirror 16b will be described later in the explanation of the IR separation illumination system of the light source device 10b below.

[0145] The IR separation illumination system of the light source device 10b consists of a convex lens 18, a convex lens 17, a dichroic mirror 16b, an IR separation dichroic mirror 28b, and a heat sink 29. In Embodiment 2, the arrangement of the IR separation dichroic mirror 28b and the heat sink 29 differs from the arrangement of the IR separation dichroic mirror 28a and the heat sink 29 in Embodiment 1. Also, in Embodiment 2, the characteristics of the dichroic mirror 16b and the IR separation dichroic mirror 28b differ from the characteristics of the dichroic mirror 16a and the IR separation dichroic mirror 28a in Embodiment 1.

[0146] As described in the explanation of the fluorescence illumination system of the light source device 10b, infrared light emitted after wavelength conversion by the phosphor layer 102 of the phosphor wheel 19a is reflected by the dichroic mirror 16b, changes direction of travel toward the IR separation dichroic mirror 28b, and enters the IR separation dichroic mirror 28b. The IR separation dichroic mirror 28b has the characteristic of transmitting light in the blue wavelength range, which is light from the laser diode light source 11, and reflecting infrared light emitted from the phosphor layer 102 of the phosphor wheel 19a. Therefore, the infrared light incident on the IR separation dichroic mirror 28b is reflected, changes direction of travel by 90 degrees, and enters the heat sink 29. The infrared light incident on the heat sink 29 is converted into heat and processed by cooling with a fan (not shown).

[0147] A description of the time-series integrator illumination system of the light source device 10b will be omitted. This is because the behavior of the light beyond the color wheel 31a, which is guided to the color wheel 31a by the blue loop optical system and the fluorescent illumination system of the light source device 10b, is the same as in Embodiment 1.

[0148] In the light source device 10b according to Embodiment 2, the phosphor layer 102 is excited by green light wavelength-converted by the phosphor layer 101 and emits infrared light wavelength-converted. The infrared light is guided to the heat sink 29 by the IR separation dichroic mirror 28b and converted into heat. As a result, the light source device 10b can suppress the temperature rise of the phosphor wheel 19a compared to when the phosphor layer 102 is not provided. As a result, the light source device 10b can suppress the occurrence of efficiency reduction and reliability problems.

[0149] <Modification 1 of Embodiment 2> Figure 15 is a schematic diagram showing an example of the configuration of the light source device 10b-1 according to Modification 1 of Embodiment 2.

[0150] The configuration of the phosphor wheel 19a-1 and the color wheel 31a-1, as well as the characteristics and position of the additional heat sink 29 and IR separation dichroic mirror 28a, and the behavior of light are the same as in the modified example 2 of Embodiment 1, so a detailed explanation is omitted.

[0151] With this configuration, the temperature rise of the phosphor wheel 19a-1 is suppressed, and by shifting the phase of the color wheel 31a-1, multiple color modes can be easily realized with the light source device 10b-1.

[0152] <Embodiment 3> Figure 16 is a schematic diagram showing an example of the configuration of the light source device 10c according to Embodiment 3.

[0153] The light source device 10c does not include an optical system that loops the light from the laser diode light source 11. The light source device 10c is configured to emit light of different wavelength ranges, such as blue, green, and red, in a time series. The light source device 10c is a light source device suitable for projection-type image display devices that use a single-panel DMD, which will be described later. The light source device 10c is composed of a plurality of laser diode light sources 11, a collimator lens 12 corresponding to each of the plurality of laser diode light sources 11, a composite mirror 40 with a blue light reflection region, a convex lens 13, a diffuser plate 14, a concave lens 15, a dichroic mirror 41 with a blue light reflection region, a convex lens 30, a color wheel 31c, a convex lens 17, a convex lens 18, a phosphor wheel 19c, a heat sink 29, and a rod integrator 32.

[0154] First, the excitation light optical system of the light source device 10c will be described. The excitation light optical system of the light source device 10c is composed of a plurality of laser diode light sources 11, a collimator lens 12 corresponding to each of the plurality of laser diode light sources 11, a composite mirror with a blue light reflection region 40, a convex lens 13, a diffuser plate 14, a concave lens 15, a dichroic mirror with a blue light reflection region 41, a convex lens 30, a color wheel 31c, a convex lens 17, and a convex lens 18.

[0155] Light emitted from each of the multiple laser diode light sources 11 is collimated by a collimator lens 12 corresponding to each laser diode light source 11. The laser diode light source 11 and collimator lens 12 set is positioned in locations corresponding to the reflection region and transmission region of the composite mirror 40 with a blue light reflection region. The transmission region of the composite mirror 40 with a blue light reflection region is located on the surface of the composite mirror 40 to which light from the laser diode light source 11 from the positive x-axis direction is incident. The reflection region of the composite mirror 40 with a blue light reflection region is located on the surface of the composite mirror 40 to which light from the laser diode light source 11 from the positive z-axis direction is incident.

[0156] Light from the laser diode light source 11 and collimator lens 12 corresponding to the reflection region of the composite mirror 40 with a blue light reflection region (i.e., the laser diode light source 11 and collimator lens 12 located in the positive z-axis direction relative to the composite mirror 40 with a blue light reflection region) is reflected by the composite mirror 40 with a blue light reflection region and travels with a 90-degree change in direction. Light from the laser diode light source 11 and collimator lens 12 corresponding to the transmission region of the composite mirror 40 with a blue light reflection region (i.e., the laser diode light source 11 and collimator lens 12 located in the positive x-axis direction relative to the composite mirror 40 with a blue light reflection region) passes through the composite mirror 40 with a blue light reflection region as is. As a result, light from multiple laser diode light sources 11 is combined by the composite mirror 40 with a blue light reflection region and incident on the subsequent convex lens 13.

[0157] Light from the laser diode light source 11, incident on the convex lens 13, is focused, reducing the beam width, and then incident on the subsequent diffuser plate 14. The light diffused by the diffuser plate 14 is incident on the subsequent concave lens 15, where it is made into a parallel beam. The light made into a parallel beam by the concave lens is then incident on a dichroic mirror 41 with a blue light reflecting region, which is positioned at an angle of approximately 45 degrees with respect to the optical axis.

[0158] The dichroic mirror 41 with a blue light reflective region transmits light from the laser diode light source 11. Furthermore, the dichroic mirror 41 with a blue light reflective region reflects infrared wavelength light from the fluorescence emitted from the phosphor wheel 19c after the light from the laser diode light source 11 has undergone wavelength conversion by the phosphor wheel 19c (described later), while transmitting green and red wavelength light. On the surface of the dichroic mirror 41 to which light from the laser diode light source 11 is incident immediately after passing through the concave lens 15, a blue light reflective region 42 is provided only in the region where light from the laser diode light source 11 is incident. This region is made of a dielectric multilayer film that reflects blue wavelength light and transmits light in other wavelength ranges. The components of the light source device 10c are arranged and formed such that blue wavelength light reflected by the color wheel 31c (described later) is incident on the region of the dichroic mirror 41 to which the blue light reflective region 42 is not provided.

[0159] The blue wavelength light from the laser diode light source 11, which is parallelized by the concave lens 15 and incident on the blue light reflection region 42 of the dichroic mirror 41 with a blue light reflection region, is reflected, its direction of propagation is changed by 90 degrees, and it is incident on the subsequent convex lens 30, and then focused on the subsequent color wheel 31c.

[0160] Figure 17 is a front view showing an example of the configuration of the color wheel 31c according to Embodiment 3.

[0161] The color wheel 31c is constructed by attaching multiple regions having predetermined properties, for example, by applying a dielectric multilayer film to the surface of a transparent substrate, to a holding portion 300 provided on the motor 306. The transparent substrate may be made of, for example, a glass plate or a sapphire substrate.

[0162] Each region of the color wheel 31c is configured in a roughly fan-shaped form. Region 301 has the property of passing through light in the blue, green, and red wavelength ranges. Region 302 has the property of reflecting light in the blue and red wavelength ranges and transmitting light in the green wavelength range. Region 303 has the property of reflecting light in the blue wavelength range and transmitting light in the green and red wavelength ranges. Region 304 has the property of reflecting light in the blue and green wavelength ranges and transmitting light in the red wavelength range.

[0163] The behavior of light from the laser diode light source 11 will be described below. Light from the laser diode light source 11 that enters region 301 of the color wheel 31c passes through the color wheel 31c and enters the subsequent rod integrator 32. The behavior of the light after it leaves the color wheel 31c will be described later in the explanation of the time-series integrator illumination system of the light source device 10c.

[0164] Light from the laser diode light source 11 that enters region 302, region 303, or region 304 of the color wheel 31c is reflected, changes direction by 180 degrees, and enters the convex lens 30 again.

[0165] The blue wavelength light from the laser diode light source 11, which is again incident on the convex lens 30, is made into parallel light and incident on the portion of the dichroic mirror 41 with a blue light reflection region other than the blue light reflection region 42.

[0166] The portion of the dichroic mirror 41 with a blue light reflective region other than the blue light reflective region 42 reflects infrared light from the fluorescence emitted from the phosphor wheel 19c after the light from the laser diode light source 11 has been wavelength-converted by the phosphor wheel 19c. Furthermore, the portion of the dichroic mirror 41 with a blue light reflective region other than the blue light reflective region 42 transmits fluorescence other than infrared light from the fluorescence emitted from the phosphor wheel 19c and blue wavelength light from the laser diode light source 11. Therefore, blue wavelength light from the laser diode light source 11 that is incident on the portion of the dichroic mirror 41 with a blue light reflective region other than the blue light reflective region 42 passes directly through the dichroic mirror 41 with a blue light reflective region 41 and is incident on the convex lens 17.

[0167] The blue wavelength light from the laser diode light source 11 that is incident on the convex lens 17 is focused by a combined optical system consisting of the convex lens 17 and the subsequent convex lens 18, and concentrated onto the phosphor layer of the phosphor wheel 19c, which will be described later.

[0168] Referring to Figure 18, the phosphor wheel 19c according to Embodiment 3 will be described. Figure 18 is a front view showing an example of the configuration of the phosphor wheel 19c according to Embodiment 3.

[0169] Unlike the phosphor wheel 19a according to Embodiments 1 and 2 shown in Figure 2, the substrate 100c of the phosphor wheel 19c does not have an opening. On the substrate 100c, there is a substantially fan-shaped layer forming a part of a ring at the same distance (on the same radius) from the rotation center of the substrate 100c, consisting of a phosphor layer 104, a phosphor layer 101, a phosphor layer 103, and a layer in which phosphor layer 101 and phosphor layer 102 are stacked. Each layer emits light in the respective wavelength ranges as fluorescence, as described in Embodiment 1.

[0170] In Embodiments 1 and 2, the phosphor wheel 19a shown in Figure 2 and the color wheel 31a shown in Figure 4 were synchronized by a synchronization circuit (not shown). Similarly, in Embodiment 3, the phosphor wheel 19c shown in Figure 18 and the color wheel 31c shown in Figure 17 were synchronized by a synchronization circuit (not shown). The phosphor wheel 19c shown in Figure 18 and the color wheel 31c shown in Figure 17 are shown in the synchronized position.

[0171] Next, the fluorescent illumination system of the light source device 10c will be described. The fluorescent illumination system consists of a convex lens 18, a convex lens 17, a dichroic mirror 41 with a blue light reflection region, and a convex lens 30, and all components are shared with the excitation light optical system.

[0172] The fluorescence (green light, red light, or infrared light) emitted from each phosphor layer of the phosphor wheel 19c is incident on two convex lenses 18 and 17, where it is made into parallel light. The parallelized fluorescence is then incident on a dichroic mirror 41 with a blue light reflecting region.

[0173] As described above, the dichroic mirror 41 with a blue light reflective region transmits light from the laser diode light source 11 and transmits light in wavelengths other than infrared light from the fluorescence emitted from the phosphor wheel 19c. The dichroic mirror 41 with a blue light reflective region is provided with a blue light reflective region 42 made of a dielectric multilayer film that reflects only blue wavelength light from the laser diode light source 11 and transmits light in other wavelengths.

[0174] Infrared light from the phosphor wheel 19c, which is incident on the dichroic mirror 41 with a blue light reflecting region, is reflected, changes direction by 90 degrees, and enters the heat sink 29. Fluorescence other than infrared light from the phosphor wheel 19c, i.e., light in the green wavelength range and light in the red wavelength range, which is incident on the dichroic mirror 41 with a blue light reflecting region, passes through the dichroic mirror 41 with a blue light reflecting region, enters the subsequent convex lens 30, and is further focused onto the subsequent color wheel 31c.

[0175] The IR-separated illumination system of the light source device 10c consists of a dichroic mirror 41 with a blue light reflection area and a heat sink 29.

[0176] As described above, the infrared light from the phosphor wheel 19c that is incident on the dichroic mirror 41 with a blue light reflecting region is reflected, changes direction by 90 degrees, and is incident on the heat sink 29. The infrared light incident on the heat sink 29 is converted into heat and cooled by a fan (not shown) or the like for processing.

[0177] Next, we will describe the behavior of light in the time-series integrator illumination system of the light source device 10c. More specifically, we will describe the behavior of light with different wavelengths over time that is guided to the color wheel 31c by the excitation light optical system and the fluorescence illumination system of the light source device 10c. The characteristics of each region of the color wheel 31c have been explained with reference to Figure 17, so we will omit the explanation here.

[0178] As described in the explanation of the behavior of light in the excitation light optical system of the light source device 10c, light from the laser diode light source 11 incident on region 301 of the color wheel 31c passes straight through the color wheel 31c.

[0179] The phosphor layer 103 of the phosphor wheel 19c corresponds to the region 302 of the color wheel 31c. Green fluorescence is emitted from the phosphor layer 103 of the phosphor wheel 19c, which is excited and wavelength-converted by blue wavelength light from the laser diode light source 11. The green fluorescence is focused onto the color wheel 31c by the fluorescence illumination system. The green fluorescence from the phosphor wheel 19c that enters region 302 of the color wheel passes through the color wheel 31c and enters the subsequent rod integrator 32.

[0180] The phosphor layers 101 and 102 of the phosphor wheel 19c correspond to the region 303 of the color wheel 31c. Yellow (green and red) fluorescence, excited and wavelength-converted by blue wavelength light from the laser diode light source 11 emitted from the phosphor layer 101 of the phosphor wheel 19c, reaches the region corresponding to the phosphor layer 101 of the phosphor wheel 19c. The yellow (green and red) fluorescence is focused onto the color wheel 31c by the fluorescence illumination system. The yellow (green and red) fluorescence from the phosphor wheel 19c that enters region 303 of the color wheel 31c passes through the color wheel 31c and enters the subsequent rod integrator 32.

[0181] In the region corresponding to the phosphor layer 102 of the phosphor wheel 19c, yellow (green and red) fluorescence and infrared fluorescence are emitted, excited and wavelength-converted by blue wavelength light from the laser diode light source 11 emitted from the phosphor layer 102 of the phosphor wheel 19c. The IR separation illumination system and the fluorescence illumination system focus the yellow (green and red) fluorescence onto the color wheel 31c. The yellow (green and red) fluorescence from the phosphor wheel 19c that enters region 303 of the color wheel 31c passes through the color wheel 31c and enters the subsequent rod integrator 32.

[0182] The phosphor layer 102 of the phosphor wheel 19c corresponds to the region 304 of the color wheel 31c. From the phosphor layer 102 of the phosphor wheel 19c, yellow (green and red) fluorescence and infrared fluorescence are emitted, which are excited and wavelength-converted by blue wavelength light from the laser diode light source 11. The IR separation illumination system and the fluorescence illumination system focus the yellow (green and red) fluorescence onto the color wheel 31c. Of the yellow fluorescence from the phosphor wheel 19c that enters region 304 of the color wheel, the light in the green wavelength range is reflected and travels in the direction of the convex lens 30 (negative z-axis direction), while the light in the red wavelength range enters the subsequent rod integrator 32.

[0183] In this embodiment, multiple color modes of the light source device 10c can be easily realized by shifting the phase of the phosphor wheel 19c relative to the color wheel 31c.

[0184] In the combination of the color wheel 31c shown in Figure 17 and the phosphor wheel 19c shown in Figure 18, light is emitted in the sequence shown in Figure 19, and the proportion of each color is as shown in Table 3 below. Figure 19 is a schematic diagram showing the time-series light emission sequence of the light source device 10c according to Embodiment 3.

[0185]

[0186] Figure 20 is a front view showing an example configuration of the phosphor wheel 19c according to Embodiment 3. The phosphor wheel 19c shown in Figure 20 has a phase shift of 22.5 degrees compared to the phosphor wheel 19c shown in Figure 18. In the combination of the color wheel 31c shown in Figure 17 and the phosphor wheel 19c shown in Figure 20, light is emitted in the sequence shown in Figure 21, and the proportion of each color is as shown in Table 4 below. Figure 21 is a schematic diagram showing the time-series light emission sequence of the light source device 10c according to Embodiment 3.

[0187]

[0188] As shown in Table 3, the combination of the color wheel 31c shown in Figure 17 and the phosphor wheel 19c shown in Figure 18 emits a large amount of red light, and as shown in Table 4, the combination of the color wheel 31c shown in Figure 17 and the phosphor wheel 19c shown in Figure 20 emits a large amount of green light. In this way, the color mode of the light source device 10c can be easily changed by changing the phase of the phosphor wheel 19c.

[0189] As described above, the light emitted from the color wheel 31c in a time series according to the positions of the phosphor wheel 19c and the color wheel 31c is incident on the rod integrator 32. The rod integrator 32 emits uniform light through multiple reflections within the rod integrator 32.

[0190] Furthermore, the green light reflected in region 304 of the color wheel 31c passes through the convex lens 30, the dichroic mirror 41 with a blue light reflection region, the convex lens 17, and the convex lens 18, and is focused onto the phosphor layer 102 on the phosphor wheel 19c. Some of the focused green light is converted back to infrared light, but the remaining green light is absorbed, causing the temperature of the phosphor wheel 19c to rise. However, because the phosphor layer 102 does not contain the energy of the infrared wavelength light that has been converted, the temperature rise of the phosphor wheel 19c is more gradual compared to when the phosphor layer 102 is not provided.

[0191] In the light source device 10c according to Embodiment 3, the phosphor layer 102 is excited by the green light wavelength-converted by the phosphor layer 101 and emits wavelength-converted infrared light. The infrared light is guided to the heat sink 29 by the dichroic mirror 41 with a blue light reflection region and converted into heat. As a result, the light source device 10c can suppress the temperature rise of the phosphor wheel 19c compared to when the phosphor layer 102 is not provided. This makes it possible for the light source device 10c to suppress the occurrence of efficiency reduction and reliability problems. Furthermore, the light source device 10c can easily realize multiple color modes by changing the phase of the phosphor wheel 19c.

[0192] <Modification 1 of Embodiment 3> Figure 22 is a schematic diagram showing an example of the configuration of a light source device 10c-1 according to Modification 1 of Embodiment 3. In the example of Figure 22, the color wheel 31c-1 has a phosphor layer (for example, a phosphor layer 210) that converts light in a specific wavelength range to infrared light. Also, the phosphor wheel 19c-1 of the light source device 10c-1 is composed of a phosphor layer 101 and a phosphor layer 103, without a phosphor layer 102 from the phosphor wheel 19c. Furthermore, the dichroic mirror 41a with a blue light reflective region of the light source device 10c-1 differs from the dichroic mirror 41 with a blue light reflective region of Embodiment 3 only in that it has the characteristic of transmitting infrared light. The characteristics of each component, the behavior of light, and the effects are the same as in Modification 2 of Embodiment 1, so a detailed explanation is omitted.

[0193] <Modification 2 of Embodiment 3> Figure 23 is a schematic diagram showing an example of the configuration of the light source device 10c-2 according to Modification 2 of Embodiment 3. In the example of Figure 23, the characteristics of each component, the behavior of light, and the effects are the same as in Modification 3 of Embodiment 1, so a detailed explanation is omitted.

[0194] <Embodiment 4> Figure 24 is a schematic diagram showing an example of the configuration of the light source device 10d according to Embodiment 4.

[0195] The light source device 10d is configured to continuously emit blue, green, and red light. The light source device 10d is a light source device suitable for projection-type image display devices that use a three-panel DMD, which will be described later.

[0196] The light source device 10d is composed of an excitation light optical system, a fluorescence illumination system, a blue light optical system, an integrator illumination system, and an IR separation illumination system.

[0197] The excitation light optical system of the light source device 10d is composed of a plurality of laser diode light sources 11, a plurality of collimator lenses 12 corresponding to each of the plurality of laser diode light sources 11, a convex lens 13, a diffuser plate 14, a concave lens 15, a dichroic mirror 16d, a convex lens 17, and a convex lens 18.

[0198] The fluorescent illumination system of the light source device 10d is composed of a phosphor wheel 19d, a convex lens 18, a convex lens 17, a dichroic mirror 16d, an IR-separating dichroic mirror 28d, and a convex lens 30.

[0199] The blue optical system of the light source device 10d is composed of a plurality of laser diode light sources 50, a plurality of collimator lenses 51 corresponding to each of the plurality of laser diode light sources 50, a convex lens 52, a diffuser plate 53, a concave lens 54, a dichroic mirror 16d, an IR-separating dichroic mirror 28d, and a convex lens 30.

[0200] The integrator illumination system of the light source device 10d is configured to include a rod integrator 32.

[0201] The IR separation illumination system of the light source device 10d consists of a convex lens 18, a convex lens 17, a dichroic mirror 16d, an IR separation dichroic mirror 28d, and a heat sink 29.

[0202] First, the excitation light optical system of the light source device 10d will be described. The excitation light optical system of the light source device 10d is identical to that of the light source device 10a according to Embodiment 1, except that the characteristics of the dichroic mirror and the direction of light propagation after the dichroic mirror are different. Here, the differences from the excitation light optical system of the light source device 10a according to Embodiment 1 will be described.

[0203] The dichroic mirror 16d transmits light in the blue wavelength range and reflects fluorescence, specifically green light, red light, or infrared light, which is excited by light from the laser diode light source 11 and wavelength-converted in the phosphor wheel 19d described later.

[0204] The parallel beams of light from multiple laser diode light sources 11, emitted from the concave lens 15, are incident on a dichroic mirror 16d, which is positioned at an angle of approximately 45 degrees with respect to the optical axis. The blue wavelength light from the laser diode light sources 11 that is incident on the dichroic mirror 16d passes straight through the dichroic mirror 16d and is focused onto the phosphor wheel 19d by passing through the subsequent convex lenses 17 and 18.

[0205] Next, the phosphor wheel 19d according to Embodiment 4 will be described with reference to Figures 25 and 3A. Figure 25 is a front view showing an example of the configuration of the phosphor wheel 19d according to Embodiment 4. The cross-sectional view of the AA section of the phosphor wheel 19d shown in Figure 25 is the same as the cross-sectional view shown in Figure 3A.

[0206] Unlike the phosphor wheel 19a of Embodiment 1, the phosphor wheel 19d of Embodiment 4 does not have an opening 105 and a phosphor layer 103. Furthermore, a phosphor layer 102 is provided on top of the phosphor layer 101, and there is no portion of the phosphor layer 101 that is exposed in the z-axis direction as in Embodiment 1. The cross-section of the phosphor wheel 19d is as shown in Figure 3A, and the behavior of light incident on the phosphor wheel 19d was explained in Embodiment 1, so it will not be explained here.

[0207] Furthermore, the phosphor layer 102 has the characteristic of emitting infrared fluorescence, which is excited and wavelength-converted in the phosphor layer 101 by light from the laser diode light source 11, for example, by light in the wavelength range at the boundary between the green wavelength range and the red wavelength range. Therefore, the fluorescence emitted from the phosphor wheel 19d is fluorescence in the green, red, or infrared wavelength range.

[0208] Next, the behavior of the light whose wavelength has been converted by the phosphor wheel 19d in a fluorescent illumination system will be explained with reference to Figure 24.

[0209] The fluorescence in the green, red, or infrared wavelength range, which has been wavelength-converted by the phosphor wheel 19d, is made into parallel light by the convex lenses 18 and 17 and incident on the dichroic mirror 16d, which is positioned at an angle of approximately 45 degrees with respect to the optical axis.

[0210] The dichroic mirror 16d transmits light in the blue wavelength range and reflects fluorescence, specifically green, red, or infrared light, that has been excited and wavelength-converted by light from the laser diode light source 11 in the phosphor wheel 19d. Therefore, fluorescence incident on the dichroic mirror 16d is reflected, changes its direction of propagation by 90 degrees, and incident on the IR-separated dichroic mirror 28d, which is positioned at an angle of approximately 45 degrees with respect to the optical axis.

[0211] The IR separation dichroic mirror 28d transmits light in the blue wavelength range and has the characteristic of passing through green and red light and reflecting infrared light, which are excited and wavelength-converted by light from the laser diode light source 11 and a portion of the fluorescence that has been wavelength-converted by light from the laser diode light source 11 in the phosphor wheel 19d, specifically green, red, or infrared light.

[0212] Of the green, red, and infrared light from the phosphor wheel 19d that is incident on the IR separation dichroic mirror 28d, the green and red light pass through and are incident on the subsequent convex lens 30, and are focused on the rod integrator 32.

[0213] The behavior of infrared light reflected by the IR-separated dichroic mirror 28d will be described later in the following explanation of the IR-separated illumination system.

[0214] The IR separation illumination system consists of an IR separation dichroic mirror 28d and a heat sink 29. The infrared light reflected and separated by the IR separation dichroic mirror 28d is incident on the heat sink 29. The heat sink 29 is provided with cooling means such as a cooling fan (not shown) to cool the heat generated when the infrared light is converted.

[0215] The blue optical system of the light source device 10d is composed of a plurality of laser diode light sources 50, a plurality of collimator lenses 51 corresponding to the plurality of laser diode light sources 50, a convex lens 52, a diffuser plate 53, a concave lens 54, a dichroic mirror 16d, an IR-separating dichroic mirror 28d, and a convex lens 30.

[0216] Light emitted from each of the multiple laser diode light sources 50 is collimated by a collimator lens 51 corresponding to each laser diode light source 50 and incident on a subsequent convex lens 52. The light from the laser diode light sources 50 incident on the convex lens 52 is focused to reduce the beam width and incident on a subsequent diffuser plate 53. The light that is incident on the diffuser plate 53 and diffused is incident on a subsequent concave lens 54 and parallelized. The light that is parallelized by the concave lens 54 is incident on a dichroic mirror 16d which is positioned at an angle of approximately 45 degrees with respect to the optical axis.

[0217] Since the dichroic mirror 16d transmits light in the blue wavelength range, the light from the laser diode light source 50 that is incident on the dichroic mirror 16d passes straight through the dichroic mirror 16d. The light from the laser diode light source 50 that has passed through the dichroic mirror 16d is incident on the IR-separated dichroic mirror 28d. Since the IR-separated dichroic mirror 28d transmits light in the blue wavelength range, the light from the laser diode light source 50 that is incident on the IR-separated dichroic mirror 28d passes straight through the IR-separated dichroic mirror 28d. The light from the laser diode light source 50 that has passed through the IR-separated dichroic mirror 28d is incident on the convex lens 30 and focused on the rod integrator 32.

[0218] The integrator illumination system of Embodiment 4 is composed of a rod integrator 32. The rod integrator 32 emits uniform light as blue light, green light, and red light, which have been focused near the rod integrator 32 by a convex lens 30, undergo multiple reflections inside the rod integrator 32.

[0219] Thus, even for a light source device 10d that is configured to constantly emit blue, green, and red light, the configuration for separating infrared light can be applied. Furthermore, according to a configuration such as Modification 1 or Modification 2 of Embodiment 4 described later, multiple color modes can be easily realized, and the temperature rise of the phosphor wheel 19d can also be suppressed.

[0220] <Modification 1 of Embodiment 4> Figure 26 is a schematic diagram showing an example of the configuration of a light source device 10d-1 according to Modification 1 of Embodiment 4. The light source device 10d-1 has a movable dichroic mirror 55 with a phosphor layer and wavelength conversion layer, instead of a color wheel.

[0221] The wavelength-converting dichroic mirror 55 is positioned between the IR-separated dichroic mirror 28d and the convex lens 30. The cross-section of the wavelength-converting dichroic mirror 55 is the same as the cross-section of the color wheel 31a-1 shown in Figure 9, with a wavelength-selective dichroic mirror layer provided on a transparent substrate. On the light incident side (the negative x-axis side in the example of Figure 26), there is a phosphor layer (for example, a phosphor layer 210) which is the wavelength-converting layer.

[0222] The dichroic mirror 55 with a wavelength conversion layer has a movement function realized by a control device (not shown). This movement function enables two modes depending on the selected color mode: one in which the dichroic mirror 55 with a wavelength conversion layer is positioned in the optical path and light rays pass through the dichroic mirror 55 with a wavelength conversion layer, and another in which the dichroic mirror 55 with a wavelength conversion layer is removed from the optical path and light rays do not pass through the dichroic mirror 55 with a wavelength conversion layer.

[0223] The mode in which light rays pass through the dichroic mirror 55 with a wavelength conversion layer is a mode that prioritizes color over brightness by removing light in a specific wavelength range from the light emitted from the light source device 10d-1. The behavior of light when the dichroic mirror 55 with a wavelength conversion layer is located in the optical path will be described below.

[0224] The dichroic mirror of the dichroic mirror with wavelength conversion layer 55 has the characteristic of reflecting light in the wavelength range to be removed and light in the infrared region, while transmitting light in the remaining wavelength range. Furthermore, the wavelength conversion layer of the dichroic mirror with wavelength conversion layer 55 has the characteristic of wavelength conversion of the light reflected by the dichroic mirror of the dichroic mirror with wavelength conversion layer 55 as excitation light, and emitting infrared fluorescence. For the sake of simplicity, the light in the wavelength range reflected by the dichroic mirror of the dichroic mirror with wavelength conversion layer 55 and the excitation light of the wavelength conversion layer will be described as light in the wavelength range between green and red. However, light in the wavelength range between green and red is only an example of the light in the wavelength range reflected by the dichroic mirror of the dichroic mirror with wavelength conversion layer 55 and the excitation light of the wavelength conversion layer, and is not limited to this.

[0225] Light from a blue optical system or fluorescent illumination system that has passed through the IR-separated dichroic mirror 28d is incident on the dichroic mirror 55 with a wavelength conversion layer. Since the wavelength conversion layer of the dichroic mirror 55 has the characteristics described above, it is excited by light in the wavelength range between green and red and emits infrared fluorescence. Due to complete diffusion, the fluorescence is also emitted on the IR-separated dichroic mirror 28d side, but the behavior of that light will be described later. First, the behavior of the light emitted on the dichroic mirror side of the dichroic mirror 55 with a wavelength conversion layer and the behavior of blue light, green light, red light, and light in the wavelength range between green and red that is transmitted to the dichroic mirror side without wavelength conversion will be explained.

[0226] The infrared light emitted after wavelength conversion in the wavelength conversion layer of the dichroic mirror 55 with wavelength conversion layer, the light in the wavelength range between green and red that was not wavelength converted, the blue light, the green light, and the red light all enter the dichroic mirror of the dichroic mirror 55 with wavelength conversion layer. Because the dichroic mirror of the dichroic mirror 55 with wavelength conversion layer has the characteristics described above, the infrared light and the light in the wavelength range between green and red are reflected, changing their direction of propagation by 180 degrees and returning to the wavelength conversion layer of the dichroic mirror 55 with wavelength conversion layer. On the other hand, the blue light, green light, and red light that have passed through the dichroic mirror of the dichroic mirror 55 with wavelength conversion layer are emitted towards the convex lens 30. The behavior of the light after it enters the convex lens 30 is the same as the behavior described in the description of Embodiment 4, so a detailed explanation is omitted.

[0227] The infrared light that returns to the wavelength conversion layer of the wavelength conversion layer-equipped dichroic mirror 55 passes through the wavelength conversion layer without wavelength conversion and is incident on the IR separation dichroic mirror 28d. The subsequent behavior of this infrared light is the same as that described in the IR separation illumination system described above, so a detailed explanation is omitted.

[0228] A portion of the light in the wavelength range between green and red that returns to the wavelength conversion layer of the dichroic mirror 55 with a wavelength conversion layer is wavelength-converted into infrared light, while the remaining light in the wavelength range between green and red that is not wavelength-converted is incident on the IR-separated dichroic mirror 28d. Strictly speaking, the infrared light produced by wavelength conversion also emits to the dichroic mirror side of the dichroic mirror 55 with a wavelength conversion layer, but as described above, it returns to the IR-separated dichroic mirror 28d side, so here we will consider it to emit to the IR-separated dichroic mirror 28d side.

[0229] The behavior of infrared light incident on the IR separation dichroic mirror 28d is similar to that of light in the IR separation illumination system described above; light in the wavelength range between green and red passes through the IR separation dichroic mirror 28d and reaches the phosphor wheel 19d.

[0230] With this configuration, infrared light can be separated and heat-treated by the wavelength conversion layer-equipped dichroic mirror 55, the IR separation dichroic mirror 28d, and the heat sink 29. Therefore, it is possible to suppress the temperature rise in the phosphor wheel 19d, and furthermore, it is possible to easily change between multiple color modes.

[0231] <Modification 2 of Embodiment 4> Figure 27 is a schematic diagram showing an example of the configuration of the light source device 10d-2 according to Modification 2 of Embodiment 3. With this configuration, by heat-treating the infrared light with two heat sinks 29, it is possible to suppress the temperature rise in the phosphor wheel 19d more than in Modification 1 of Embodiment 4, and furthermore, it is possible to easily change between multiple color modes.

[0232] <Embodiment 5> Figure 28 is a schematic diagram showing an example of the configuration of the light source device 10e according to Embodiment 5.

[0233] The light source device 10e is configured to continuously emit blue, green, and red light. The light source device 10e is a light source device suitable for projection-type image display devices that use a three-panel liquid crystal panel, as described later.

[0234] The light source device 10e is composed of an excitation light optical system, a fluorescence illumination system, a blue light optical system, an integrator illumination system, and an IR separation illumination system.

[0235] The excitation light optical system of the light source device 10e includes a plurality of laser diode light sources 11, a plurality of collimator lenses 12 corresponding to each of the plurality of laser diode light sources 11, a convex lens 13, a diffuser plate 14, a concave lens 15, a λ / 2 phase difference plate 60, an IR-separated dichroic mirror 28b, a dichroic mirror with polarization separation function 61, a convex lens 17, and a convex lens 18. λ represents the wavelength of light.

[0236] The fluorescent illumination system of the light source device 10e is comprised of a phosphor wheel 19b, a convex lens 18, a convex lens 17, a dichroic mirror 61 with polarization separation function, an IR separation dichroic mirror 28b, and a heat sink 29.

[0237] The blue optical system of the light source device 10e is composed of a plurality of laser diode light sources 11, a plurality of collimator lenses 12 corresponding to each of the plurality of laser diode light sources 11, a convex lens 13, a diffuser plate 14, a concave lens 15, a λ / 2 phase difference plate 60, an IR-separated dichroic mirror 28b, a dichroic mirror with polarization separation function 61, a λ / 4 phase difference plate 62, and a total reflection mirror 63.

[0238] The integrator illumination system of the light source device 10e is composed of a pair of fly-eye integrators 64 and a Polarization Beam Splitter (hereinafter referred to as "PBS") array 65.

[0239] The IR-separated illumination system of the light source device 10e is composed of a convex lens 18, a convex lens 17, a dichroic mirror 61 with polarization separation function, an IR-separated dichroic mirror 28b, and a heat sink 29.

[0240] The excitation light optical system of the light source device 10e differs from the excitation light optical system of the light source device 10b according to Embodiment 2 in the following respects. In the excitation light optical system of the light source device 10e, a λ / 2 phase difference plate 60 is provided between the concave lens 15 and the IR-separating dichroic mirror 28b. Furthermore, in the excitation light optical system of the light source device 10e, the blue light emitted from multiple laser diode light sources 11 is arranged so that the polarization directions are aligned. The dichroic mirror 61 with polarization separation function transmits P-polarized light and reflects S-polarized light from the blue wavelength range of light from the laser diode light sources 11, and transmits green and red light from the fluorescence from the phosphor wheel 19d, while reflecting infrared light.

[0241] As described above, the light emitted from each of the multiple laser diode light sources 11, whose polarization directions are aligned, is made into parallel light by reducing the beam width through the collimator lens 12, convex lens 13, diffuser plate 14, and concave lens 15 corresponding to each light source, and then incident on the subsequent λ / 2 phase difference plate 60.

[0242] The λ / 2 phase difference plate 60 is held rotatably with respect to the optical axis by a holding mechanism (not shown). The λ / 2 phase difference plate 60 also has the function of delaying the phase of the polarization vibration direction in the slow phase axis direction by λ / 2, corresponding to the wavelength of light from the laser diode light source 11, and can rotate the polarization direction of the light from the laser diode light source 11. By changing the rotation direction of the λ / 2 phase difference plate 60, the ratio of P-polarized light transmitted through the dichroic mirror 61 with polarization separation function to S-polarized light reflected can be changed, and ultimately it is possible to optimize the ratio of blue, green, and red light emitted from the light source device 10e.

[0243] Light from the laser diode light source 11, whose polarization direction is optimized by the λ / 2 phase difference plate 60, is incident on the IR-separated dichroic mirror 28b. The IR-separated dichroic mirror 28b has the characteristic of transmitting light in the blue wavelength range from the laser diode light source 11 and reflecting infrared light from the fluorescence excited by the light from the laser diode light source 11 and wavelength converted in the phosphor wheel 19d. The light from the laser diode light source 11 that is incident on the IR-separated dichroic mirror 28b passes through the IR-separated dichroic mirror 28b as is and is incident on the dichroic mirror 61 with polarization separation function.

[0244] The dichroic mirror 61 with polarization separation function transmits P-polarized light from the blue wavelength range of the laser diode light source 11 and reflects S-polarized light. It also transmits green and red light from the fluorescence excited by the light from the laser diode light source 11 and wavelength-converted in the phosphor wheel 19d, and reflects infrared light. Of the light from the laser diode light source 11 incident on the dichroic mirror 61 with polarization separation function, S-polarized light is reflected and incident on the subsequent convex lens 17. The S-polarized light from the laser diode light source 11 incident on the convex lens 17 is focused onto the phosphor layer of the phosphor wheel 19d. The behavior of P-polarized light from the laser diode light source 11 incident on the dichroic mirror 61 with polarization separation function will be described later in the explanation of the blue optical system.

[0245] The phosphor wheel 19d of the light source device 10e in Embodiment 5 has the same configuration, function, and light behavior as the phosphor wheel 19d of the light source device 10d in Embodiment 4, so its description is omitted here. The fluorescence emitted from the phosphor wheel 19d is green, red, or infrared fluorescence.

[0246] The green, red, or infrared fluorescence emitted after wavelength conversion by the phosphor wheel 19d passes through the convex lenses 18 and 17 to become parallel light, and is incident on a dichroic mirror 61 with polarization separation function, which is positioned at an angle of approximately 45 degrees with respect to the optical axis.

[0247] Of the fluorescence incident on the dichroic mirror 61 with polarization separation function, the green and red light passes directly through the dichroic mirror 61 with polarization separation function and is incident on the integrator illumination system described later.

[0248] Furthermore, infrared light from the fluorescence incident on the dichroic mirror 61 with polarization separation function is reflected by the dichroic mirror 61 with polarization separation function, changes its direction of propagation by 90 degrees, and then incident on the IR separation dichroic mirror 28b.

[0249] In the IR separation illumination system, infrared light incident on the IR separation dichroic mirror 28b is reflected by the IR separation dichroic mirror 28b, changes its direction of travel by 90 degrees, and then incident on the heat sink 29. The heat sink 29 is provided with cooling means such as a cooling fan (not shown), which cools the heat generated by the conversion of infrared light.

[0250] The blue optical system of the light source device 10e, consisting of multiple laser diode light sources 11, multiple collimator lenses 12, a convex lens 13, a diffuser plate 14, a concave lens 15, a λ / 2 phase difference plate 60, an IR-separated dichroic mirror 28b, and a dichroic mirror 61 with polarization separation function, is shared with the excitation light optical system.

[0251] Of the light from the laser diode light source 11 that has passed through the dichroic mirror 61 with polarization separation function, the P-polarized light is incident on the subsequent λ / 4 phase difference plate 62.

[0252] The λ / 4 phase difference plate 62 has the function of delaying the phase of the polarization vibration direction in the slow phase axis direction by λ / 4, corresponding to the wavelength of light from the laser diode light source 11. The slow phase axis of the λ / 4 phase difference plate 62 is positioned rotated 45 degrees around the optical axis with respect to the vibration direction of P-polarized light from the laser diode light source 11 that has passed through the dichroic mirror 61 with polarization separation function. As a result, the P-polarized light from the laser diode light source 11 is changed to circularly polarized light.

[0253] The light, which has become circularly polarized after passing through the λ / 4 phase difference plate 62, is incident on the subsequent total internal reflection mirror 63, is reflected, changes direction by 180 degrees, and is then incident on the λ / 4 phase difference plate 62 again.

[0254] The circularly polarized light that is again incident on the λ / 4 phase difference plate 62 has its phase in the direction of polarization vibration delayed by λ / 4, which changes it from circularly polarized to S-polarized, and it is then incident on the dichroic mirror 61 with polarization separation function again.

[0255] S-polarized light incident on the dichroic mirror 61 with polarization separation function is reflected, changes its direction of propagation by 90 degrees, and then incident on the integrator illumination system described later.

[0256] Next, we will explain the behavior of the green and red light from the phosphor wheel 19d of the fluorescent lighting system and the blue light from the laser diode light source 11 of the blue optical system in the integrator lighting system of the light source device 10e after they are emitted from the dichroic mirror 61 with polarization separation function.

[0257] The green and red light from the phosphor wheel 19d of the fluorescent illumination system, and the blue light from the laser diode light source 11 of the blue optical system, are homogenized by a pair of fly-eye integrators 64, and the polarization direction of the light in all wavelength ranges is unified by the PBS array 65 before emission.

[0258] Thus, even for a light source device 10e that is configured to constantly emit blue, green, and red light, the configuration for separating infrared light can be applied. Furthermore, according to a configuration such as Modification 1 or Modification 2 of Embodiment 5 described later, multiple color modes can be easily realized, and the temperature rise of the phosphor wheel 19d can also be suppressed.

[0259] <Modification 1 of Embodiment 5> Figure 29 is a schematic diagram showing an example of the configuration of a light source device 10e-1 according to Modification 1 of Embodiment 5. The light source device 10e-1 does not have a color wheel, but rather a movable dichroic mirror 55 with a wavelength conversion layer equipped with a phosphor layer. The dichroic mirror 55 with a wavelength conversion layer was described above in the description of Modification 1 of Embodiment 4, so its description is omitted here. In addition, the phosphor wheel 19d-1 of the light source device 10e-1 is a phosphor wheel that does not have a phosphor layer 102, but is composed of a phosphor layer 101 all around. With this configuration, infrared light can be separated and heat-treated by the dichroic mirror 55 with a wavelength conversion layer, the IR separation dichroic mirror 28b, and the heat sink 29. Therefore, it is possible to suppress the temperature rise in the phosphor wheel 19d, and furthermore, it is possible to easily change between multiple color modes.

[0260] <Modification 2 of Embodiment 5> Figure 30 is a schematic diagram showing an example of the configuration of the light source device 10e-2 according to Modification 2 of Embodiment 5. With this configuration, by heat-treating the infrared light with two heat sinks 29, it is possible to suppress the temperature rise in the phosphor wheel 19d more than in Modification 1 of Embodiment 5, and furthermore, it is possible to easily change between multiple color modes.

[0261] [Projection-type Image Display Device] Next, a projection-type image display device 400a having a light source device 10a-2 according to modification 3 of Embodiment 1 will be described with reference to Figure 31. Figure 31 is a schematic diagram showing an example configuration of a projection-type image display device 400a including a light source device 10a-2 according to modification 3 of Embodiment 1. The projection-type image display device 400a uses a single-board DMD (DMD 404). Note that the projection-type image display device 400a may have a light source device 10a according to Embodiment 1, a light source device 10a-1 according to modification 2 of Embodiment 1, a light source device 10b according to Embodiment 2, a light source device 10b-1 according to Embodiment 2, a light source device 10c according to Embodiment 3, a light source device 10c-1 according to modification 1 of Embodiment 3, or a light source device 10c-2 according to modification 2 of Embodiment 3 instead of the light source device 10a-2 according to modification 3 of Embodiment 1. Here, an example in which the projection-type image display device 400a has a light source device 10a-2 will be described.

[0262] The projection-type image display device 400a comprises a light source device 10a-2, a convex lens 401, a convex lens 402, a convex lens 403, a DMD 404, a total internal reflection prism 406, and a projection lens 407.

[0263] The description of the configuration and behavior of the light source device 10a-2 will be omitted, and the behavior of the light emitted from the rod integrator 32, whose wavelength changes over time, will be described.

[0264] The optical system consisting of convex lens 401, convex lens 402, convex lens 403, DMD 404, and total internal reflection prism 406 is sometimes referred to as the relay lens optical system of the projection-type image display device 400a. Furthermore, the three convex lenses 401, 402, and 403 are sometimes collectively referred to as the relay lens. The relay lens may be designed so that light with different wavelengths over time, emitted from the aperture of the rod integrator 32 of the light source device 10a-2, is guided to the DMD 404, which will be described later.

[0265] The total internal reflection prism 406 is composed of two prisms with a small gap 405 in between. Light emitted from the relay lens and incident on the total internal reflection prism 406 is reflected by the small gap 405 at an angle greater than the total internal reflection angle, changing the direction of light propagation and guiding it to the DMD 404.

[0266] The DMD 404 is composed of multiple minute mirrors corresponding to pixels, and a video circuit (not shown) changes the tilt direction of each of the multiple minute mirrors in accordance with the video signal, thereby changing the direction of light propagation. The light from the light source device 10a-2, whose wavelength range changes over time and whose direction of propagation has been changed by the DMD 404, is incident on the total internal reflection prism 406 as video light.

[0267] The projection optical system of the projection-type image display device 400a consists of a DMD 404, a total internal reflection prism 406, and a projection lens 407. Image light, whose wavelength range changes over time, is emitted from the DMD 404 and enters the total internal reflection prism 406. Here, the image light enters the minute gap 405 at an angle less than or equal to the total internal reflection angle, thereby passing through the total internal reflection prism 406 without changing the direction of light propagation. The image light then exits the total internal reflection prism 406, enters the projection lens 407, and is subsequently projected onto a screen (not shown).

[0268] Thus, the projection-type image display device 400a may be configured to include a light source device (light source device 10a-2 in the example of Figure 31) that has the effect of suppressing the temperature rise of the phosphor wheel (phosphor wheel 19a-1 in the example of Figure 31). This makes it possible to suppress the occurrence of efficiency reduction and reliability problems in the projection-type image display device 400a, and also makes it possible to easily change between multiple color modes.

[0269] Next, a projection-type image display device 400d having a light source device 10d-2 according to a modification 2 of Embodiment 4 will be described with reference to Figure 32. Figure 32 is a schematic diagram showing an example configuration of a projection-type image display device 400d including a light source device 10d-2 according to a modification 2 of Embodiment 4. The projection-type image display device 400d uses a three-panel DMD (DMD509, DMD510, and DMD511).

[0270] The projection-type image display device 400d comprises a light source device 10d-2, a convex lens 501, a convex lens 502, a convex lens 503, a total internal reflection prism 507, a dichroic prism (described later), three DMDs (DMD 509, DMD 510, and DMD 511), and a projection lens 508.

[0271] The configuration and behavior of the light source device 10d-2 will be omitted, and the behavior of the blue light, green light, and red light emitted from the rod integrator 32 will be described.

[0272] The optical system consisting of convex lens 501, convex lens 502, convex lens 503, total internal reflection prism 507, dichroic prism (described later), and three DMDs (DMD 509, DMD 510, and DMD 511) is sometimes referred to as the relay lens optical system of the projection-type image display device 400d. The three convex lenses 501, 502, and 503 are sometimes collectively referred to as the relay lens. The relay lens may be designed so that light of different wavelengths, i.e., blue light, green light, and red light, emitted from the aperture of the rod integrator 32 of the light source device 10d-2, is guided to each of the three DMDs described later.

[0273] The total internal reflection prism 507 is composed of two prisms with a small gap 512 in between. Light emitted from the relay lens and incident on the total internal reflection prism 507 is reflected by the small gap 512 at an angle greater than the total internal reflection angle, changing the direction of light propagation and guiding it to the dichroic prism.

[0274] The dichroic prism is composed of three glass blocks 504, 505, and 506. A small gap 514 is provided between the first glass block 504 and the second glass block 506 from the light incident side. Furthermore, the total internal reflection prism 507 and the dichroic prism are arranged so that a small gap 513 is provided between them.

[0275] The behavior of blue, red, and green light emitted from the total internal reflection prism 507 will be explained in order.

[0276] Blue light emitted from the total internal reflection prism 507 and incident on the first glass block 504 of the dichroic prism is reflected by a dichroic reflective layer (not shown) formed between the glass block 504 and the second glass block 506 of the dichroic prism, which has the property of reflecting blue light. The reflected blue light is then incident on a minute gap 513 provided between the first glass block 504 of the dichroic prism and the total internal reflection prism 507 at an angle greater than the total internal reflection angle, reflected, changes direction of propagation, and is guided to the blue light DMD 509 positioned on the surface of the glass block 504. The dichroic reflective layer may be made of, for example, a dielectric multilayer film.

[0277] Red light emitted from the total internal reflection prism 507 and incident on the first glass block 504 of the dichroic prism passes through the dichroic reflective layer that reflects blue light between the glass block 504 and the second glass block 506 of the dichroic prism, and is incident on the second glass block 506. The red light incident on the second glass block 506 is reflected by a dichroic reflective layer (not shown) that has the property of reflecting red light and is provided between the glass block 506 and the third glass block 505 of the dichroic prism. The reflected red light is incident on the minute gap 514 between the glass block 504 and the glass block 506 at an angle greater than the total internal reflection angle, is reflected again, changes direction of propagation, and is guided to the red DMD 511 positioned on the surface of the glass block 506.

[0278] Green light emitted from the total internal reflection prism 507 and incident on the first glass block 504 of the dichroic prism passes through the dichroic reflective layer that reflects blue light between glass block 504 and the second glass block 506 of the dichroic prism, and incident on the second glass block 506. The green light incident on the second glass block 506 passes through the dichroic reflective layer that reflects red light, which is provided between glass block 506 and the third glass block 505 of the dichroic prism, and incident on the third glass block 505. The green light incident on glass block 505 is guided to the green DMD 510 positioned on the surface of glass block 505.

[0279] Each DMD (DMD509, DMD510, and DMD511) for blue, green, and red light is composed of multiple micro-mirrors corresponding to pixels. An image circuit (not shown) changes the tilt direction of each of the micro-mirrors in each DMD in response to the image signal, thereby changing the direction of light propagation. The red, blue, and green light, whose direction of propagation has been changed by each DMD, is then incident on a dichroic prism.

[0280] The projection optical system of the projection-type image display device 400d consists of three DMDs (DMD 509, DMD 510, and DMD 511), a total internal reflection prism 507, and a projection lens 508. The behavior of green light, red light, and blue light, whose direction of propagation is changed according to the video signal by each of the green, red, and blue DMDs will be described in order below.

[0281] The green light emitted from the green DMD 510 and incident on the glass block 505 passes through the dichroic reflective layer that reflects red light, which is provided between the glass block 505 and the glass block 506. The green light then passes through the minute gap 514 provided between the glass block 504 and the glass block 506 by being incident at an angle less than or equal to the angle of total internal reflection. The green light then passes through the dichroic reflective layer that reflects blue light, which is provided between the glass block 504 and the glass block 506, and is incident on the glass block 504. The green light incident on the glass block 504 passes through the minute gap 513 between the glass block 504 and the total internal reflection prism 507 by being incident at an angle less than or equal to the angle of total internal reflection, and is incident on the total internal reflection prism 507.

[0282] Red light emitted from the red DMD 511 and incident on the glass block 506 is reflected when it is incident on the minute gap 514 provided between glass block 504 and glass block 506 at an angle greater than or equal to the total internal reflection angle. The reflected red light changes direction of travel towards the dichroic reflective layer that reflects red light, provided between glass block 505 and glass block 506. Red light incident on the dichroic reflective layer that reflects red light is reflected and changes direction of travel towards the minute gap 514 provided between glass block 504 and glass block 506. Then, the red light passes through the minute gap 514 provided between glass block 504 and glass block 506 by being incident on at an angle less than or equal to the total internal reflection angle. The red light further passes through the dichroic reflective layer that reflects blue light, provided between glass block 504 and glass block 506, and is incident on glass block 504. The red light incident on the glass block 504 passes through the minute gap 513 between the glass block 504 and the total internal reflection prism 507 at an angle less than or equal to the total internal reflection angle, and then enters the total internal reflection prism 507.

[0283] The blue light emitted from the blue-emitting DMD 509 and incident on the glass block 504 is reflected when it is incident on the minute gap 513 between the glass block 504 and the total internal reflection prism 507 at an angle greater than or equal to the total internal reflection angle. The reflected blue light changes its direction of travel towards the dichroic reflective layer that reflects blue light, which is provided between the glass block 504 and the glass block 506, and continues to travel. The blue light then incident on the dichroic reflective layer that reflects blue light, which is provided between the glass block 504 and the glass block 506, is reflected, and is transmitted through the minute gap 513 between the glass block 504 and the total internal reflection prism 507 at an angle less than or equal to the total internal reflection angle, and then incident on the total internal reflection prism 507.

[0284] Blue, red, and green light incident on the total internal reflection prism 507 pass straight through the prism 507 by entering the minute gap 512 of the prism 507 at an angle less than or equal to the total internal reflection angle. The light of each color emitted from the total internal reflection prism 507 enters the projection lens 508 and is then projected onto a screen (not shown).

[0285] Thus, the projection-type image display device 400d may be configured to have a light source device (light source device 10d-2 in the example of Figure 32) that can separate infrared light from the optical path and can easily change between multiple color modes. This makes it possible to separate infrared light from the optical path in the projection-type image display device 400d as well. Furthermore, it becomes possible to easily change between multiple color modes in the projection-type image display device 400d, and at the same time, it becomes possible to suppress the temperature rise of the phosphor wheel 19d.

[0286] Next, a projection-type image display device 400e having a light source device 10e-2 according to a modification 2 of Embodiment 5 will be described with reference to Figure 33. Figure 33 is a schematic diagram showing an example configuration of a projection-type image display device 400e including a light source device 10e-2 according to a modification 2 of Embodiment 5. The projection-type image display device 400e uses a three-panel liquid crystal panel (liquid crystal panel 605, liquid crystal panel 610, and liquid crystal panel 618).

[0287] The projection-type image display device 400e consists of a light source device 10e-2, a red illumination system, a green illumination system, a blue illumination system, three sets of liquid crystal panels equipped with polarizing plates, and a projection optical system.

[0288] The description of the configuration and behavior of the light source device 10e-2 will be omitted, and the behavior of the blue light, green light, and red light emitted from the PBS array 65 will be described.

[0289] The red illumination system of the projection-type image display device 400e comprises a convex lens 601, a dichroic mirror 602, a total reflection mirror 603, and a convex lens 604. The red illumination system is designed so that the red light emitted from the PBS array 65 of the light source device 10e is superimposed onto the red liquid crystal panel 605, which will be described later, by the two convex lenses.

[0290] Red light emitted from the light source device 10e-2 and passing through the convex lens 601 is incident on a dichroic mirror 602, which is positioned at an angle of approximately 45 degrees to the optical axis. The dichroic mirror 602 has the characteristic of reflecting light in the red wavelength range and transmitting light in the green wavelength range and blue wavelength range. The red light incident on the dichroic mirror 602 is reflected by the dichroic mirror 602, changes its direction of travel by 90 degrees, and is incident on the subsequent total internal reflection mirror 603. The red light is reflected by the total internal reflection mirror 603, changes its direction of travel by 90 degrees, and is incident on the convex lens 604. The red light then passes through the polarizing plate 606, which will be described later, and is superimposed onto the red liquid crystal panel 605.

[0291] The green illumination system of the projection-type image display device 400e comprises a convex lens 601, a dichroic mirror 602, a dichroic mirror 608, and a convex lens 609. The green illumination system is designed so that the green light emitted from the PBS array 65 of the light source device 10e is superimposed onto the green liquid crystal panel 610, which will be described later, by the two convex lenses. The convex lens 601 and dichroic mirror 602 of the green illumination system are also shared with the red illumination system.

[0292] Green light emitted from the light source device 10e-2 and passing through the convex lens 601 is incident on a dichroic mirror 602, which is positioned at an angle of approximately 45 degrees with respect to the optical axis. The dichroic mirror 602 has the characteristic of reflecting light in the red wavelength range and transmitting light in the green wavelength range and light in the blue wavelength range. The green light incident on the dichroic mirror 602 passes straight through the dichroic mirror 602 and is incident on a subsequent dichroic mirror 608, which is positioned at an angle of approximately 45 degrees with respect to the optical axis.

[0293] The dichroic mirror 608 has the property of reflecting light in the green wavelength range and transmitting light in the blue wavelength range. Green light incident on the dichroic mirror 608 is reflected, changes its direction of propagation by 90 degrees, and then incident on the convex lens 609. The green light then passes through the polarizing plate 611, which will be described later, and is superimposed onto the green liquid crystal panel 610.

[0294] The blue illumination system of the projection-type image display device 400e includes a convex lens 601, a dichroic mirror 602, a dichroic mirror 608, a convex lens 613, a total reflection mirror 614, a convex lens 615, a total reflection mirror 616, and a convex lens 617. The blue illumination system is designed so that the blue light emitted from the PBS array 65 of the light source device 10e is superimposed onto the blue liquid crystal panel 618, which will be described later, by the convex lens 601 and a relay system composed of three convex lenses. In addition, the convex lens 601, dichroic mirror 602, and dichroic mirror 608 of the blue illumination system are shared with the green illumination system.

[0295] Blue light emitted from the light source device 10e-2 and passing through the convex lens 601 is incident on a dichroic mirror 602, which is positioned at an angle of approximately 45 degrees with respect to the optical axis. The dichroic mirror 602 has the characteristic of reflecting light in the red wavelength range and transmitting light in the green wavelength range and blue wavelength range. The blue light incident on the dichroic mirror 602 passes straight through the dichroic mirror 602 and is incident on a subsequent dichroic mirror 608, which is positioned at an angle of approximately 45 degrees with respect to the optical axis.

[0296] The dichroic mirror 608 has the property of reflecting light in the green wavelength range and transmitting light in the blue wavelength range. Blue light incident on the dichroic mirror 608 passes straight through the dichroic mirror 608 and is incident on the subsequent convex lens 613.

[0297] The blue light is relayed and its direction of travel is changed by three convex lenses (convex lens 613, convex lens 615, and convex lens 617) and two total reflection mirrors (total reflection mirror 614 and total reflection mirror 616). The blue light then passes through a polarizing plate 619, which will be described later, and is superimposed onto the blue liquid crystal panel 618.

[0298] Each of the red liquid crystal panel 605, green liquid crystal panel 610, and blue liquid crystal panel 618 is provided with polarizing plates on both the light-incident and light-emitting sides. The red liquid crystal panel 605 has a polarizing plate 606 on the light-incident side and a polarizing plate 607 on the light-emitting side. The green liquid crystal panel 610 has a polarizing plate 611 on the light-incident side and a polarizing plate 612 on the light-emitting side. The blue liquid crystal panel 618 has a polarizing plate 619 on the light-incident side and a polarizing plate 620 on the light-emitting side. Since the behavior of each color liquid crystal panel is similar, the following explanation will describe the light incident on the liquid crystal panel without limiting it to a specific color.

[0299] The red, green, and blue light, whose polarization directions are unified by the PBS array 65 of the light source device 10e-2, are incident on the polarizing plates positioned on the incident side of each liquid crystal panel without changing the polarization direction in each of the red, green, and blue illumination systems. Since the polarization direction of the light emitted from the PBS array 65 matches the polarization direction transmitted through the polarizing plates, the light from the light source device 10e-2 emitted from the PBS array 65 passes through the polarizing plates.

[0300] The liquid crystal panel, using an image circuit (not shown), changes the polarization direction of a minute area corresponding to a pixel in response to the image signal, and emits light incident on the liquid crystal panel. The light emitted from the liquid crystal panel passes through a polarizing plate located on the output side of the liquid crystal panel, and is emitted as image light of each pixel with different intensities corresponding to the image signal.

[0301] The projection optical system of the projection-type image display device 400e comprises three sets of liquid crystal panels, each equipped with a polarizing plate on the light incident side and the light exit side, a cross-cube prism 621, and a projection lens 622.

[0302] As shown in Figure 33, the four faces of the cross-cube prism 621 are each facing a red liquid crystal panel 605 equipped with a polarizer, a green liquid crystal panel 610 equipped with a polarizer, a blue liquid crystal panel 618 equipped with a polarizer, and a projection lens 622, respectively. In the example in Figure 33, the green liquid crystal panel 610 is positioned directly facing the projection lens 622. The cross-cube prism 621 also has a dichroic mirror reflective layer that reflects red light and transmits green and blue light, and a dichroic mirror reflective layer that reflects blue light and transmits green and red light.

[0303] The red light emitted from the red liquid crystal panel 605 enters a dichroic mirror reflective layer located inside the cross-cube prism 621, which reflects red light and transmits green and blue light, and is reflected. The reflected red light changes direction by 90 degrees and is emitted from the cross-cube prism 621, entering the projection lens 622.

[0304] The blue light emitted from the blue liquid crystal panel 618 enters a dichroic mirror reflective layer located inside the cross-cube prism 621, which reflects blue light and transmits green and red light, and is reflected. The reflected blue light changes direction by 90 degrees and is emitted from the cross-cube prism 621, entering the projection lens 622.

[0305] The green light emitted from the green liquid crystal panel 610 passes through a dichroic mirror reflective layer inside the cross cube prism 621 that reflects red light and transmits green and blue light, and another dichroic mirror reflective layer that reflects blue light and transmits green and red light. The green light is then emitted from the cross cube prism 621 and incident on the projection lens 622.

[0306] The red, green, and blue light combined by the cross-cube prism 621 are then incident on the projection lens 622 and projected onto a screen (not shown).

[0307] In the example shown in Figure 33, a relay system is used in a blue lighting system; however, a relay system may also be used in a green lighting system or a red lighting system.

[0308] Thus, the projection-type image display device 400e may be configured to have a light source device (light source device 10e-2 in the example of Figure 33) that can separate infrared light from the optical path and can easily change between multiple color modes. This makes it possible to separate infrared light from the optical path in the projection-type image display device 400e as well. Furthermore, it becomes possible to easily change between multiple color modes in the projection-type image display device 400e, and at the same time, it becomes possible to suppress the temperature rise of the phosphor wheel 19d.

[0309] (Summary of Embodiments) The following technologies are disclosed based on the descriptions of the various embodiments above. The components etc. in the above embodiments are examples, but are not limited to these.

[0310] (Technical 1) The light source device (for example, light source device 10a) includes a light source (for example, a laser diode light source 11), a wavelength conversion element (for example, a phosphor wheel 19a) that converts excitation light from the light source to light in different wavelength ranges, a wavelength selection element (for example, a color wheel 31a) that reflects light in a specific wavelength range from the light from the wavelength conversion element, and an optical separation means (for example, an IR separation dichroic mirror 28a) that is arranged on the optical path of the light from the wavelength conversion element and separates light in a specific wavelength range from the light from the wavelength conversion element.

[0311] As a result, even when light reflected by a wavelength-selective element, such as a color wheel, is focused by a wavelength-converting element, such as a phosphor wheel, causing the temperature of the wavelength-converting element to rise, the temperature rise of the wavelength-converting element is suppressed compared to when the light in that specific wavelength range is not separated, because light in that specific wavelength range is separated from the reflected light.

[0312] (Technology 2) In the light source device described in Technology 1, the wavelength conversion element comprises a first phosphor layer (e.g., phosphor layer 101) and a second phosphor layer (e.g., phosphor layer 102), wherein the first phosphor layer is configured to include a first phosphor that wavelength-converts excitation light to fluorescence in a different first wavelength range, and the second phosphor layer is configured to include a second phosphor that wavelength-converts light in a specific wavelength range from fluorescence to light in a second wavelength range different from the first wavelength range (e.g., infrared light).

[0313] As a result, excitation light incident on the first phosphor layer of a wavelength conversion element, such as a phosphor wheel, is wavelength-converted. Then, when the wavelength-converted fluorescence is incident on the second phosphor layer, light in a specific wavelength range from that fluorescence is wavelength-converted to infrared light and emitted from the second phosphor layer.

[0314] (Technology 3) In the light source device described in Technology 1 or 2, the light separation means separates infrared light from the light from the wavelength conversion element.

[0315] As a result, when light from a wavelength conversion element, such as a phosphor wheel, is incident on an optical separation means, such as an IR separation dichroic mirror, the infrared wavelength range of the light can be separated by the optical separation means.

[0316] (Technology 4) In the light source device described in Technology 2 or 3, the second phosphor converts the light in the green wavelength range of the fluorescence into infrared light.

[0317] As a result, when excitation light from a light source is incident on the first phosphor layer, its wavelength is converted, and then the resulting fluorescence is incident on the second phosphor layer, the light in the green wavelength range of that fluorescence can be converted to infrared light.

[0318] (Technology 5) In the light source device described in any one of Techniques 2 to 4, the second phosphor layer is provided on the first phosphor layer and is arranged so that reflected light from the wavelength-selective element is incident on it.

[0319] As a result, the light emitted from the second phosphor layer is separated from the infrared light along its optical path, then incident on the color wheel and reflected. The reflected light from the color wheel is then focused onto the second phosphor layer. Here, since the reflected light from the color wheel does not contain light in the infrared wavelength range, the temperature rise of the wavelength conversion element, such as the phosphor wheel containing the second phosphor layer, due to the focus onto the second phosphor layer is suppressed.

[0320] (Technology 6) In the light source device described in any one of Techniques 2 to 5, the thickness of the second phosphor layer (e.g., thickness t2) is thinner than the thickness of the first phosphor layer (e.g., thickness t1).

[0321] This suppresses the temperature rise of the second phosphor layer, and consequently, the temperature rise of wavelength conversion elements such as phosphor wheels.

[0322] (Technology 7) In a light source device (e.g., light source device 10a-1) described in any one of Techniques 1 to 6, the wavelength conversion element (e.g., phosphor wheel 19a-1) has a first wavelength conversion layer that converts excitation light into a first fluorescence, and the wavelength selection element (e.g., color wheel 31a-1) has a transmission layer (e.g., region 205) that transmits a second fluorescence which is a part of the first fluorescence, and a second wavelength conversion layer (e.g., phosphor layer 210) that is arranged to cover at least a part of the surface of the transmission layer on the side where light is incident when viewed from the optical axis direction, the second wavelength conversion layer converts a third fluorescence which is light in a different wavelength range from the second fluorescence of the first fluorescence into a fourth fluorescence, and the light separation means separates the fourth fluorescence from the light from the wavelength selection element.

[0323] As a result, when yellow light, for example, is emitted from the wavelength conversion element as the first fluorescence and incident on the wavelength selection element, a second fluorescence, such as red light, which is part of the yellow light, can pass through the transmission layer. In addition, a third fluorescence, such as green light, which is light in a different wavelength range from the second fluorescence (in this case, red light) of the yellow light, is converted into a fourth fluorescence by the second wavelength conversion layer. The fourth fluorescence may be, for example, infrared light. The light separation means can separate the fourth fluorescence (in this case, infrared light) from the light from the wavelength selection element (for example, infrared light and green light that has not been wavelength converted). This suppresses the incidence of the fourth fluorescence on the wavelength conversion element and suppresses the temperature rise of the wavelength conversion element.

[0324] The specific colored lights listed as examples of fluorescence are merely illustrative and do not limit the wavelength range of fluorescence.

[0325] (Technology 8) In the light source device described in any one of Technology 1 to 7, the wavelength conversion element and the wavelength selection element are each rotatable.

[0326] As a result, the wavelength conversion element and the wavelength selection element are configured to be rotatable.

[0327] (Technology 9) In the light source device described in any one of Techniques 1 to 8, the wavelength conversion element and the wavelength selection element are rotatable in synchronization.

[0328] As a result, the wavelength conversion element and the wavelength selection element are configured to rotate in sync with each other.

[0329] (Technology 10) In the light source device described in any one of Technologies 1 to 9, the wavelength conversion element and the wavelength selection element are rotatable in a plurality of different relative phases.

[0330] This allows the light source device to achieve multiple color modes by shifting the phase between the wavelength conversion element and the wavelength selection element.

[0331] (Technology 11) In the light source device described in any one of Techniques 1 to 10, the light separation means is arranged between the wavelength conversion element and the wavelength selection element.

[0332] As a result, the light separation means can separate light in a specific wavelength range from, for example, light traveling from a wavelength-selective element to a wavelength-converting element.

[0333] (Technical 12) In the light source device described in Technical 7, the fourth fluorescence is light in the infrared wavelength range.

[0334] This allows the light separation means to separate infrared light.

[0335] (Technical 13) A projection-type image display device (for example, a projection-type image display device 400a) has a light source device as described in any one of Technical 1 to 12.

[0336] As a result, the projection-type image display device can obtain the same effect as the light source device described in any one of the technologies 1 to 12.

[0337] Although various embodiments have been described above with reference to the drawings, it goes without saying that this disclosure is not limited to these examples. It will be clear to those skilled in the art that various modifications, alterations, substitutions, additions, deletions, and equivalents can occur within the scope of the claims, and these will naturally fall within the technical scope of this disclosure. Furthermore, the components of the various embodiments described above can be combined arbitrarily without departing from the spirit of the invention.

[0338] This disclosure is useful as a light source device and a projection-type image display device.

[0339] 10a, 10a-1, 10a-2, 10b, 10b-1, 10c, 10c-1, 10c-2, 10d, 10d-1, 10d-2, 10e, 10e-1, 10e-2 Light source device 11, 50 Laser diode light source 12, 51 Collimator lens 13, 17, 18, 20, 21, 23, 25, 27, 30, 52, 401, 402, 403, 501, 502, 503, 601, 604, 609, 613, 615, 617 Convex lens 14, 53 Diffuser plate 15, 54 Dichroic mirror with concave lens wavelength conversion layer 55 16a, 16b, 16d, 602, 608 Dichroic mirror 19a, 19a-1, 19b, 19c, 19d Phosphor wheel 22, 24, 26, 63, 603, 614, 616 Total reflection mirror 28a, 28b, 28d IR-separated dichroic mirror 29 Heat sink 31a, 31a-1, 31c, 31c-1 Color wheel 32 Rod integrator 40 Composite mirror with blue light reflection region 41 Dichroic mirror with blue light reflection region 42 Blue light reflection region 60 λ / 2 phase difference plate 62 λ / 4 phase difference plate 64 Fly-eye integrator 65 PBS array 100a, 100c Substrate 101, 102, 103, 210 Phosphor layer 104 Reflection layer 105 Aperture 106, 206, 306 Motor 200 Holding part 201, 202, 203, 204, 205, 301, 302, 303, 304 Area 220 Transparent substrate 300 Holding part 400a, 400d, 400e Projection type image display device 404, 509, 510, 511 DMD 405, 512, 513, 514 Microgap 406, 507 Total internal reflection prism 407, 508, 622 Projection lens 504, 505, 506 Glass block 605 Red liquid crystal panel 606, 607, 611, 612, 619, 620 Polarizing plate 610 Green liquid crystal panel 618 Blue liquid crystal panel 621 Cross cube prism

Claims

1. A light source device comprising: a light source; a wavelength conversion element that converts excitation light from the light source into light of a different wavelength range; a wavelength selection element that reflects light of a specific wavelength range from the light from the wavelength conversion element; and a light separation means arranged on the optical path of the wavelength-converted light from the wavelength conversion element to the wavelength selection element, which separates light of a specific wavelength range from the wavelength-converted light from the wavelength conversion element and guides it out of the optical path.

2. The light source device according to claim 1, wherein the wavelength conversion element comprises a first phosphor layer and a second phosphor layer, the first phosphor layer comprising a first phosphor that wavelength-converts the excitation light to fluorescence in a different first wavelength range, and the second phosphor layer comprising a second phosphor that wavelength-converts light in a specific wavelength range from the fluorescence to light in a second wavelength range different from the first wavelength range.

3. The light source device according to claim 2, wherein the second phosphor converts light in a specific wavelength range from the fluorescence to infrared light.

4. The light source device according to claim 3, wherein the light separation means separates the infrared light from the light from the wavelength conversion element.

5. The light source device according to claim 4, wherein the second phosphor converts the wavelength of light in the green wavelength range of the fluorescence to infrared light.

6. The light source device according to claim 5, wherein the second phosphor layer is provided on the first phosphor layer and is arranged so that reflected light from the wavelength-selecting element is incident on it.

7. The light source device according to claim 5, wherein the first phosphor layer is provided on the second phosphor layer and is arranged so that reflected light from the wavelength-selecting element is incident on it.

8. The light source device according to claim 3, wherein the thickness of the second phosphor layer is thinner than the thickness of the first phosphor layer.

9. The light source device according to claim 1, wherein the wavelength conversion element has a first wavelength conversion layer that converts the excitation light into a first fluorescence, the wavelength selection element has a transmission layer that transmits a second fluorescence which is a part of the first fluorescence, and a second wavelength conversion layer that is arranged to cover at least a part of the surface of the transmission layer on the side where light is incident when viewed from the optical axis direction, the second wavelength conversion layer converts a third fluorescence which is light in a different wavelength range from the second fluorescence of the first fluorescence into a fourth fluorescence, and the light separation means separates the fourth fluorescence from the light from the wavelength selection element.

10. The light source device according to claim 9, wherein the wavelength conversion element and the wavelength selection element are each rotatable.

11. The light source device according to claim 10, wherein the wavelength conversion element and the wavelength selection element are rotatable in synchronization.

12. The light source device according to claim 11, wherein the wavelength conversion element and the wavelength selection element are rotatable in a plurality of different relative phases.

13. The light source device according to claim 9, wherein the light separation means is disposed between the wavelength conversion element and the wavelength selection element.

14. The light source device according to claim 9, wherein the fourth fluorescence is light in the infrared wavelength range.

15. A projection-type image display device having a light source device according to any one of claims 1 to 14.

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