Wavelength conversion wheel, light source device, and projection image display device

Abstract

This wavelength conversion wheel converts incident light into light of a different wavelength. The wavelength conversion wheel comprises a substrate that can rotate around a rotational axis and one or more wavelength conversion elements that are provided on the substrate and include a wavelength conversion material that is excited by incident light and emits light of a different wavelength from the incident light. The wavelength conversion elements are formed from segments. The segments are demarcated by an inside arced edge, an outside arced edge, and end edges that connect endpoints of the inside arced edge and the outside arced edge on respective sides. The outside arced edge includes a first arc part that has the same shape and arc length as the inside arced edge. The one or more wavelength conversion elements are arranged such that the concave sides of the inside arced edges and the outside arced edges are directed toward the inside of the substrate.

Description

Technical Field

[0001] The present disclosure relates to, for example, a wavelength conversion wheel, a light source device, and a projection type video display device used in a light source device of a projection type video display device.

Background Art

[0002] A wavelength conversion wheel using a wavelength conversion element containing a phosphor has been used in a so-called mixed layer type wavelength conversion element in which phosphor particles are dispersed and applied in a resin paste, and a sintered body type wavelength conversion element composed of a sintered body of phosphor particles. For example, there is a wavelength conversion wheel using a sintered body type wavelength conversion element disclosed in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A wavelength conversion wheel using a sintered body type wavelength conversion element is superior in conversion efficiency and heat resistance to a wavelength conversion wheel using a mixed layer type wavelength conversion element, but the manufacturing cost of the wavelength conversion element is an issue.

[0005] In manufacturing a wavelength conversion wheel, in addition to a method of creating a phosphor ring of a sintered material and adhering it to a substrate, individual segments are cut off from a plate-shaped sintered body material along a cutting line on the surface of the plate-shaped sintered body material, for example, by laser scribing, to form a wavelength conversion element and constitute the wavelength conversion wheel. At this time, the yield and production efficiency of the wavelength conversion wheel depend greatly on the arrangement of the segments forming the wavelength conversion element on the plate-shaped sintered body material and the cutting distance when separating the individual segments.

[0006] Therefore, the purpose of this disclosure is to provide a wavelength conversion wheel that can improve production efficiency and yield. [Means for solving the problem]

[0007] To achieve the above objective, a wavelength conversion wheel according to one aspect of the present disclosure is a wavelength conversion wheel that converts incident light into light of a different wavelength, comprising: a substrate rotatable about a rotation axis; and one or more wavelength conversion elements disposed on the substrate and comprising a wavelength conversion material that is excited by incident light and emits light of a different wavelength from the wavelength of the incident light, wherein the wavelength conversion elements are composed of segments, each segment defined by an inner arc edge, an outer arc edge, and two side edges connecting the endpoints on both sides of the inner arc edge and the outer arc edge, the outer arc edge includes a first arc-shaped portion having the same shape and arc length as the inner arc edge, and the one or more wavelength conversion elements are arranged such that the concave sides of the inner arc edge and the outer arc edge face inward towards the substrate. [Effects of the Invention]

[0008] The wavelength conversion wheel described herein can improve production efficiency and yield. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram shows the annular segments that make up a conventional wavelength conversion element. [Figure 2] This is an image diagram and a magnified view of a partial region showing multiple annular segments from Figure 1 arranged on a plate-shaped sintered material. [Figure 3A] This figure shows an example of the configuration of segments constituting the wavelength conversion element according to Embodiment 1 of Embodiment 1. [Figure 3B] This figure shows an example of the configuration of segments constituting a wavelength conversion element according to Embodiment 2 of Embodiment 1. [Figure 4A] This is an illustrative diagram showing multiple segments, as shown in Figure 3A, arranged on a plate-shaped sintered material. [Figure 4B] This is an illustrative diagram showing multiple segments, as shown in Figure 3B, arranged on a plate-shaped sintered material. [Figure 5] This figure shows the outer arc edge end of a segment constituting a wavelength conversion element according to Embodiment 2 of the present disclosure. [Figure 6A] This figure shows an example of the configuration of the outer arc edge end of a segment according to Embodiment 1 of Embodiment 2. [Figure 6B] This figure shows an example of the configuration of the outer arc edge end of a segment according to Embodiment 2 of Embodiment 2. [Figure 6C] This figure shows an example of the configuration of the outer arc edge end of a segment according to Embodiment 3 of Embodiment 2. [Figure 6D] This figure shows an example of the configuration of the outer arc edge end of a segment according to Embodiment 4 of Embodiment 2. [Figure 7] This figure shows an example of the configuration of segments constituting the wavelength conversion element according to Embodiment 2. [Figure 8] This is a simplified diagram and an enlarged view of a partial region showing multiple segments according to Embodiment 2 arranged on a plate-shaped sintered material. [Figure 9] This is a side view showing an example of the configuration of a wavelength conversion wheel according to Embodiment 3 of the present disclosure. [Figure 10A] This is a schematic plan view showing an example of the planar configuration of the wavelength conversion wheel according to Embodiment 1 of Embodiment 3. [Figure 10A1] This is a schematic plan view showing an example of a planar configuration of a wavelength conversion wheel according to a modified example of Embodiment 1 shown in Figure 10A. [Figure 10B] This is a schematic plan view showing an example of the planar configuration of the wavelength conversion wheel according to Embodiment 2 of Embodiment 3. [Figure 10B1] This is a schematic plan view showing an example of a planar configuration of a wavelength conversion wheel according to a modified example of Embodiment 2 shown in Figure 10B. [Figure 10C] This is a schematic plan view showing an example of the planar configuration of the wavelength conversion wheel according to Embodiment 3 of Embodiment 3. [Figure 10D] This is a schematic plan view showing an example of the planar configuration of the wavelength conversion wheel according to Embodiment 4 of Embodiment 3. [Figure 11] This figure shows an example of the configuration of a light source device according to Embodiment 4 of the present disclosure. [Figure 12]FIG. 11 is a diagram showing a configuration example of a projection type video display device including a light source device shown in FIG. 11. [Figure 13] FIG. 3 is a diagram showing a configuration example of a light source device according to Embodiment 5 of the present disclosure. [Figure 14] FIG. 13 is a diagram showing a configuration example of a projection type video display device including a light source device shown in FIG. 13. [Figure 15] FIG. 6 is a diagram showing a configuration example of a light source device according to Embodiment 6 of the present disclosure. [Figure 16] FIG. 15 is a diagram showing a configuration example of a projection type video display device including a light source device shown in FIG. 15. [Figure 17] FIG. 7 is a diagram showing a configuration example of a light source device according to Embodiment 7 of the present disclosure. [Figure 18] FIG. 17 is a diagram showing a configuration example of a projection type video display device including a light source device shown in FIG. 17.

DETAILED DESCRIPTION OF THE INVENTION

[0010] According to the first aspect of the present disclosure, there is provided a wavelength conversion wheel that converts incident light into light of different wavelengths, including a substrate rotatable about a rotation axis, and one or more wavelength conversion elements disposed on the substrate, excited by the incident light, and emitting light having a wavelength different from the wavelength of the incident light. The wavelength conversion element is composed of segments, and each segment is defined by an inner arc edge, an outer arc edge, and both side edges connecting the endpoints on both sides of the inner arc edge and the outer arc edge. The outer arc edge includes a first arcuate portion having the same shape and arc length as the inner arc edge. The one or more wavelength conversion elements are arranged such that the concave sides of the inner arc edge and the outer arc edge face the inside of the substrate.

[0011] According to this aspect, it is possible to provide a wavelength conversion wheel capable of improving production efficiency and yield.

[0012] According to a second aspect of the present disclosure, the wavelength conversion wheel according to the first aspect is provided, wherein the outer arc edge has an inflection point near at least one end edge of the segment, between the endpoint of the outer arc edge on one side and the endpoint of the first arc shape, and the outer arc edge end containing the inflection point has a shape different from that of the inner arc edge.

[0013] According to a third aspect of the present disclosure, the wavelength conversion wheel described in the second aspect is provided, wherein the outer arc edge end is composed of a second arc shape and a third arc shape, the second arc shape and the third arc shape have opposite curvature directions and are in contact at an inflection point.

[0014] A fourth aspect of this disclosure provides a wavelength conversion wheel according to the third aspect, wherein the first and second arc-shaped portions lie on the circumference of a first circle, the third arc-shaped portion lies on the circumference of a second circle, and the first and second circles are circular circles that are circumscribed at an inflection point.

[0015] According to a fifth aspect of this disclosure, a wavelength conversion wheel according to the second aspect is provided, wherein the outer arc edge end is composed of a straight section passing through an inflection point.

[0016] A wavelength conversion wheel according to the fifth aspect of this disclosure is provided, wherein one endpoint of the first arc-shaped portion and one of the straight portions lie on the circumference of the first circle, one endpoint of the straight portion lies on the circumference of the second circle, and the first and second circles are circular circles that are circumscribed at the inflection point.

[0017] According to a seventh aspect of this disclosure, a wavelength conversion wheel according to any one of the first to sixth aspects is provided, wherein the endpoints on the same side of the first arc-shaped portion and the inner arc edge lie on a straight line perpendicular to the straight line connecting the two endpoints of the inner arc edge.

[0018] According to an eighth aspect of this disclosure, a wavelength conversion wheel according to the first aspect is provided, wherein the endpoints on the same side of the first arc-shaped portion and the inner arc edge are located on one of the end edges.

[0019] According to a ninth aspect of the present disclosure, a wavelength conversion wheel according to any one of the second to seventh aspects is provided, wherein the inflection point is located only near one end edge, and the endpoints on the same side of the first arc-shaped portion and the inner arc edge are located on the other end edge.

[0020] According to a tenth aspect of the present disclosure, a wavelength conversion wheel is provided according to any one of the first to ninth aspects, wherein the wavelength conversion element is arranged in a ring shape including a partially missing portion around a rotation axis, and the substrate has an opening at a position corresponding to the missing portion of the wavelength conversion element.

[0021] According to an eleventh aspect of this disclosure, a wavelength conversion wheel is provided according to any one of the first to ninth aspects, wherein the wavelength conversion element is arranged in a ring shape including a partially missing portion around a rotation axis, and the substrate has a reflective region at a position corresponding to the missing portion of the wavelength conversion element.

[0022] According to a twelfth aspect of this disclosure, a wavelength conversion wheel is provided according to any one of the first to ninth aspects, wherein the wavelength conversion element is arranged in a ring shape around a rotation axis, and a portion of the ring shape is a reflection region.

[0023] According to a thirteenth aspect of this disclosure, a wavelength conversion wheel is provided according to any one of the first to twelfth aspects, wherein the first arc-shaped portion of one or more wavelength conversion elements is arranged along a circumference centered on a rotation axis.

[0024] According to a fourteenth aspect of this disclosure, a wavelength conversion wheel is provided, comprising two or more wavelength conversion elements including wavelength conversion materials that emit light of different wavelengths, as described in any one of the first to thirteenth aspects.

[0025] According to a 15th aspect of this disclosure, a light source device is provided, comprising a light source that emits incident light and a wavelength conversion wheel as described in any one of the 1st to 14th aspects.

[0026] According to the sixteenth aspect of this disclosure, a projection-type image display device is provided, comprising: a light source device as described in the fifteenth aspect; an optical modulation element that modulates incident light according to an image signal; an illumination optical system that guides illumination light emitted from the light source device to the optical modulation element; and a projection optical system that magnifies and projects the emitted light from the optical modulation element to display an image.

[0027] Furthermore, by appropriately combining any of the above various embodiments, the effects of each can be achieved.

[0028] <The process leading to the present invention> First, the process leading to the present invention will be explained with reference to Figures 1 and 2.

[0029] Figure 1 shows a conventional annular segment 31 constituting a wavelength conversion element. Figure 2 shows an image and a magnified view of a partial region in which multiple annular segments of Figure 1 are arranged on a plate-shaped sintered material 30. A wavelength conversion wheel is used, for example, in a projection-type image display device to convert incident light into light of one or more different wavelengths. Generally, a wavelength conversion wheel used in a projection-type image display device is constructed by attaching a wavelength conversion element, which includes a wavelength conversion material that emits light of a different wavelength from the wavelength of the incident light when excited by the incident light, to a rotatable disc-shaped substrate in a ring shape. The wavelength conversion material is not limited to this, but includes, for example, various phosphors that are excited by incident light and generate fluorescence of various wavelengths.

[0030] Conventional wavelength conversion elements generally consist of an annular segment 31 as shown in Figure 1. As shown in the figure, the annular segment 31 has an annular region enclosed by an outer arc 31a and an inner arc 31b having the same central angle Φ, and edges 31c and 31d on both sides. The outer arc 31a lies on the circumference C31a with a radius of curvature r31a, and the inner arc 31b lies on the circumference C31b with a different radius of curvature r31b than the circular C31a. A wavelength conversion element composed of such an annular segment can be fixed on a substrate so that the outer arc forms a circumference, thereby forming a wavelength conversion wheel with a ring-shaped planar shape.

[0031] The annular segment 31 shown in Figure 1 is formed by cutting a plate-shaped sintered material to create individual parts. In order to increase the utilization rate of the plate-shaped sintered material, as shown in Figure 2, it is conceivable to form segments 31A, 32A, and 33A with aligned edges in the plate-shaped sintered material 30, where annular segments of the same shape are aligned. Furthermore, adjacent segments can be arranged in opposite directions with their edges touching each other. In this specification, "segment" refers to a portion of a sintered material having a predetermined shape for constituting a wavelength conversion element, which has been individually manufactured from a plate-shaped sintered material.

[0032] However, in the arrangement shown in Figure 2, for example, in the central region S1 of the same segment row, the inner arc 311b of the annular segment 311 and the outer arc 312a of the vertically adjacent annular segment 312 do not overlap. Therefore, in order to separate the annular segment 311 and the annular segment 312, it is necessary to cut along the respective cutting lines of arc 311b and arc 312a. Also, as shown in the enlarged view, in the end region S2 where adjacent segment rows meet, for example, the outer arc 312a of the annular segment 312 and the outer arc 322a of the annular segment 322 that meets at the end do not overlap. Therefore, in order to separate the respective adjacent arcs in the end region S2, cutting along their respective cutting lines is required.

[0033] Therefore, the present inventors investigated a wavelength conversion wheel that shortens the cutting distance when separating individual segments from a plate-shaped sintered material, enabling easy and efficient separation of segments constituting a wavelength conversion element, and arrived at the following invention.

[0034] The embodiments will be described in detail below, with reference to the drawings as appropriate. However, unnecessarily detailed explanations may be omitted. For example, detailed explanations of already well-known matters and redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding for those skilled in the art.

[0035] A light source device according to Embodiment 1 of this disclosure, and a projection display device equipped with such a light source device, will be described with reference to Figures 3A to 17. The accompanying drawings and the following description 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. In addition, elements are exaggerated in each figure for the sake of clarity. Substantially identical components in the drawings are denoted by the same reference numerals.

[0036] <Segments that make up the wavelength conversion element> (Embodiment 1) The segments constituting the wavelength conversion element according to Embodiment 1 of this disclosure will be described with reference to Figures 3A to 4B. Figure 3A is a diagram showing an example of the configuration of segment 10A constituting the wavelength conversion element according to Example 1 of Embodiment 1. Figure 3B is a diagram showing an example of the configuration of segment 10B constituting the wavelength conversion element according to Example 2 of Embodiment 1. Figure 4A is an image diagram showing multiple segments of Figure 3A arranged on a plate-shaped sintered material 30A. Figure 4B is an image diagram showing multiple segments of Figure 3B arranged on a plate-shaped sintered material 30B. In this specification, the length of the radius used to determine the geometric shape of a circle is expressed as the "radius of curvature," and the line connecting the center of the circle and a point on the circumference is expressed as the "radius" to distinguish between the two.

[0037] The segment 10A shown in Figure 3A has an arched shape defined by an outer arc edge Aab, an inner arc edge Bab, and two edge points 10c and 10d that connect the endpoints A1a and A1b of the outer arc edge Aab to the endpoints B1a and B1b of the inner arc edge Bab, respectively. The outer arc edge Aab of segment 10A includes a first arc-shaped section 10a between endpoints A2a and A2b. In this embodiment, endpoint A2a of the first arc-shaped section 10a and endpoint B1a of the inner arc edge Bab lie on a straight line n1 perpendicular to the straight line m connecting the two endpoints of the inner arc edge Bab, and endpoint A2b of the first arc-shaped section 10a and endpoint B1b of the inner arc edge Bab lie on a straight line n2 perpendicular to the straight line m connecting the two endpoints of the inner arc edge Bab. Thus, the first arc-shaped section 10a has substantially the same shape and arc length as the inner arc edge Bab.

[0038] In this embodiment, the first arc-shaped portion 10a lies on the circumference of a circle C10a with a radius of curvature r10 centered at O1, and the endpoints A1a and A1b of the outer arc edge Aab are on the circumference of circle C10a and lie on a pair of radii R10a and R10b, respectively, forming a central angle θ1. The inner arc edge Bab lies on the circumference of circle C10b, and its endpoints B1a and B1b lie on radii R10a and R10b, respectively. Circles C10a and C10b have the same radius of curvature r10 but different centers. However, this disclosure is not limited thereto. The first arc-shaped portion 10a and the inner arc edge Bab may each have an arc shape and are not limited to circular arcs. Also, in this embodiment, as shown in the figure, the segment 10A is configured symmetrically with respect to the center line n, and the first arc-shaped portion 10a and the inner arc edge Bab are configured symmetrically with respect to the center line n. However, this disclosure is not limited thereto. For example, the first arc-shaped section 10a may be configured asymmetrically with respect to the center line n, and the segment 10A may have a configuration asymmetrically with respect to the center line n. For the convenience of explanation in the following description, the segment 10A in Figure 3A will be referred to as the "arch-shaped segment".

[0039] Furthermore, in this specification, "same shape and arc length" does not mean completely identical shape and arc length, but rather may include, in practice, tolerances in manufacturing, such as an error of approximately ±5 degrees or an error of approximately ±0.5 mm, but still be substantially the same shape and arc length.

[0040] In Figure 3A, segment 10A is shown to have a central angle θ1 of approximately 120 degrees. However, the disclosure is not limited thereto. Depending on the application, the segment may be configured to have any central angle less than 360 degrees, preferably 180 degrees or less.

[0041] Furthermore, in this embodiment, both end edges 10c and 10d are configured to lie on radii R10a and R10b, respectively. However, the disclosure is not limited thereto. The end edges of the segment may have any length and, depending on the application, may be composed of, for example, straight lines or curves that do not lie on the radii.

[0042] The partial arched segment 10B shown in Figure 3B has an asymmetrical configuration and can be formed to be substantially a part of the arched segment 10A shown in Figure 3A. For convenience of explanation, in the following description, segment 10B in Figure 3B will be referred to as the "partial arched segment".

[0043] As shown in Figure 3B, the partially arched segment 10B has a shape defined by Aab1, which is a part of the outer arc edge Aab of segment 10A; Bab1, which is a part of the inner arc edge Bab; and the end edges 10e and 10d on both sides. The outer arc edge Aab1 also includes a first arc-shaped portion 10a1 between the endpoints A2a1 and A2b. In this embodiment, the first arc-shaped portion 10a1 and the inner arc edge Bab1 are arcs on circles C10a and C10b, respectively, and circles C10a and C10b have the same radius of curvature r10.

[0044] In this embodiment, the endpoint A2a1 of the first arc-shaped portion 10a1 of the outer arc edge Aab1 and the endpoint B2a of the inner arc edge Bab lie on the edge 10e of the partial arch-shaped segment 10B. The first arc-shaped portion 10a1 between endpoints A2a1 and A2b has substantially the same shape and arc length as the inner arc edge Bab1.

[0045] As shown in the figure, in this embodiment, the partial arch-shaped segment 10B can be formed by cutting it with a secant line n perpendicular to the straight line m connecting the two ends of the inner arc edge Bab of the arch-shaped segment 10A. The wavelength conversion element composed of the partial arch-shaped segment cut with a secant line perpendicular to the straight line connecting the two ends of the inner arc edge can be easily arranged rotationally symmetrically on the disc-shaped substrate of the wavelength conversion wheel.

[0046] In this embodiment, the partial arched segment 10B shown in Figure 3B is half of the arched segment cut by a secant line which is the center line n. Therefore, the central angle θ2 of the partial arched segment 10B is half of the central angle θ1 of the arched segment 10A, which is about 60 degrees. However, the disclosure is not limited thereto. The partial arched segment may also be a part of an arched segment cut by another secant line, and can be configured to have any central angle less than 360 degrees, for example. Furthermore, the partial arched segment is preferably configured to have a central angle of 180 degrees or less, and more preferably to have a central angle of 90 degrees or less.

[0047] In the plate-shaped sintered material 30A shown in Figure 4A, multiple arch-shaped segments of the same shape form segment rows 110A, 120A, and 130A with aligned edges, and adjacent segment rows are arranged in opposite directions with their edges touching each other. Compared to the annular segment shown in Figure 2, in the arch-shaped segments, for example, in the central region S1 of the same segment row, the inner arc edge 111b of arch-shaped segment 111A and the first arc-shaped portion 112a of the outer arc edge of the vertically adjacent arch-shaped segment 112A overlap each other. This allows vertically adjacent arch-shaped segments to be separated along a common cutting line, and the cutting distance when separating individual segments can be shortened.

[0048] In the arrangement shown in Figure 4A, during the process of individualizing the segments, the cutting process, for example, starting from the end region S3 of the plate-shaped sintered material 30A, proceeds by repeatedly cutting along the edge of the segment row using sawtooth cutting lines. Therefore, for example, the partially arched segment 10B shown in Figure 3B can be separated from the plate-shaped sintered material 30B shown in Figure 4B, which is obtained by cutting the plate-shaped sintered material 30A along the cutting lines P1 and P2 shown in Figure 4A. As shown, the plate-shaped sintered material 30B does not have an end region S3 that includes sawtooth cutting lines, and the rows of partially arched segments 110B and 130B can be easily separated from the end of the plate-shaped sintered material 30B. Furthermore, for example, by further cutting along the cutting line P3 shown in Figure 4B, the partially arched segment can be easily separated from the central part of the plate-shaped sintered material 30B. Thus, the partially arched segment simplifies and improves the efficiency of the cutting process.

[0049] Thus, the arched segment or partially arched segment according to Embodiment 1 is configured to have a curvature that coincides with the first arced portion of the outer arc edge and the inner arc edge, allowing segments within a segment row to be separated along a common cutting line. By shortening the cutting distance when separating individual segments, production efficiency and yield can be improved.

[0050] (Embodiment 2) The segments constituting the wavelength conversion element according to Embodiment 2 of this disclosure will be described with reference to Figures 5 to 8. Figure 5 is a diagram showing the outer arc edge end of the segment constituting the wavelength conversion element according to Embodiment 2 of this disclosure. Figures 6A to 6D are diagrams showing examples of the configuration of the outer arc edge end of the segment according to each of Examples 1 to 4 of Embodiment 2. Figure 7 is a diagram showing an example of the configuration of segment 10A5 constituting the wavelength conversion element according to Embodiment 2 of this disclosure. Figure 8 is a simplified image diagram and an enlarged view of a partial region S2 showing the segment according to Embodiment 2 of this disclosure arranged on a plate-shaped sintered material 30. It should be understood that the configuration of the outer arc edge end of the segment according to this disclosure is not limited to the configuration examples shown in Figures 5 to 7.

[0051] The segment constituting the wavelength conversion element according to Embodiment 2 of this disclosure has a basic shape based on the arch-shaped segment 10A shown in Figure 3A, or the partially arch-shaped segment 10B shown in Figure 3B. That is, the outer arc edge end of the segment shown in Figures 5 to 7 may be applied to the arch-shaped segment or to the partially arch-shaped segment, for example. In the following description, "arch-shaped segment" and "partially arch-shaped segment" will be collectively referred to as "segment".

[0052] As shown in Figure 5, the outer arc edge Aab (only a portion is shown) of segment 10A having the basic shape shown in Figure 3A or Figure 3B has an outer arc edge end near the end edge 10d. This outer arc edge end has an inflection point F between the endpoint A1 of the outer arc edge Aab and the endpoint A2 of the first arc-shaped portion 10a, and may have a different shape from the inner arc edge Bab. Here, an "inflection point" refers to a point at which the arc changes from concave to convex or vice versa.

[0053] Figures 5 to 7 show the outer arc edges of adjacent segments. In the embodiment shown in Figure 5, segment 10A and segment 20A adjacent to segment 10A have the basic shape shown in Figure 3A or Figure 3B. The first arc shape 10a of the outer arc edge Aab of segment 10A (only a portion is shown) and the first arc shape 20a of the outer arc edge Cab of segment 20A (only a portion is shown) lie on circles C10a and C20a, respectively, and circles C10a and C20a are externally tangent at the inflection point F. Note that the radius of curvature r20 of circle C20a and the radius of curvature r10 of circle C10a may be the same or different.

[0054] In this embodiment, near the edge 10d of segment 10A, the outer arc edge end of the outer arc edge Aab, which includes an inflection point F, is formed, and the inflection point F is located between the outer arc edge Aab endpoint A1 and the first arc shape 10a endpoint A2. Furthermore, by forming the outer arc edge end of the outer arc edge Aab to have an arc shape including the inflection point F or a straight section passing through the inflection point F, a common outer arc edge end between adjacent segments 10A and 20A can be formed. In this case, the common outer arc edge end between adjacent segments 10A and 20A can be defined by the inflection point F, the endpoints A1 and A2 on the outer arc edge Aab of segment 10A, and the endpoints C1 and C2 on the outer arc edge Cab of segment 20A. Furthermore, in this embodiment, the inflection point F and the endpoints C1 and C2 are positioned by the radius of curvature r10 of circle C10a, the radius of curvature r20 of circle C20a, and the central angles θ1 of segment 10A and θ3 of segment 20A. In this embodiment, θ1 and θ3 are the same angle.

[0055] For example, in this embodiment, endpoint C2 is defined as the intersection of a straight line h1 containing radius R10b having endpoint B1 of segment 10A and circle C20a, and endpoint C1 is defined as the intersection of a straight line h2 parallel to the straight line h1 and passing through endpoint A2 and circle C20a. In this case, as shown in the figure, inflection point F is substantially the intersection of the diagonals of a parallelogram formed by endpoints A2 and B1 in segment 10A and endpoints C2 and D1 in segment 20A. Note that the configuration of the segments, or the positioning of endpoints A1, A2, C1, C2 and inflection point F, takes into account manufacturing tolerances. For example, in this specification, the "intersection" of a straight line and a straight line, or a straight line and a circle, may include an error of, for example, ±0.5 mm, and the orientation of the arc may include an error of, for example, ±5 degrees.

[0056] In Embodiment 1 shown in Figure 6A, a common outer arc edge end is formed between adjacent segments 10A1 and 20A1. Segment 10A1 includes endpoint C2 in segment 20A1, and segment 20A1 may include endpoint A2 in segment 10A1. Segment 10A1 has an edge 10d1 defined by endpoints B1 and C2, and segment 20A1 has an edge 20d1 defined by endpoints D1 and A2. In this case, segments 10A1 and 20A1 have a common inflectional arc edge AC1a. The inflectional arc edge AC1a is formed by a second arc shape 10i on the circumference of circle C10a and a third arc shape 20i on the circumference of circle C20a, and the second arc shape 10i and the third arc shape 20i are in contact at the inflection point F. In other words, the inflected arc edge AC1a is defined by a curve connecting endpoints A2 and C2, and this curve changes direction at the inflection point F. As shown in the figure, the second arc shape 10i between endpoint A2 and the inflection point F and the third arc shape 20i between the inflection point F and endpoint C2 have opposite curvature directions. Here, "curvature direction" means an increase or decrease in the slope of the tangent to the arc when moving along the shape of the arc, and "opposite curvature direction" means that the slope of the tangent to the arc changes from an increase to a decrease or from a decrease to an increase. For example, in the second arc shape 10i and the third arc shape 20i shown in Figure 6A, the way the arc bends changes at the inflection point F, from a decreasing slope to an increasing slope.

[0057] Next, in Embodiment 2 shown in Figure 6B, similar to Embodiment 1, a common outer arc edge end is formed for adjacent segments 10A2 and 20A2. Segment 10A2 includes endpoint C2 in segment 20A2, and segment 20A2 includes endpoint A2 in segment 10A2. Furthermore, segment 10A2 has an edge 10d2 defined by endpoints B1 and C2, and segment 20A2 has an edge 20d2 defined by endpoints D1 and A2. However, in this case, segments 10A2 and 20A2 have a common straight section AC1b. The straight section AC1b is formed by a straight line 10f connecting endpoints A2 and C2, and the straight line 10f substantially passes through an inflection point F.

[0058] Next, in Embodiment 3 shown in Figure 6C, a common outer arc edge end is formed between adjacent segments 10A3 and 20A3. Segment 10A3 includes endpoint C1 in segment 20A3, and segment 20A3 includes endpoint A1 in segment 10A3. Furthermore, segment 10A3 has an edge 10d3 defined by endpoints B1 and A1, and segment 20A3 has an edge 20d3 defined by endpoints D1 and C1. In this case, segments 10A3 and 20A3 have a common inflectional arc edge AC1c. The inflectional arc edge AC1c is formed by a second arc shape 10k on the circumference of circle C10a and a third arc shape 20k on the circumference of circle C20a, and the second arc shape 10k and the third arc shape 20k are in contact at the inflection point F. In other words, the inflection arc edge AC1c is defined by a curve connecting endpoints C1 and A1, and this curve changes direction at the inflection point F. As shown in the figure, the third arc shape 20k between endpoint C1 and inflection point F and the second arc shape 10k between inflection point F and endpoint A1 have opposite curvature directions.

[0059] Next, in Embodiment 4 shown in Figure 6D, similar to Embodiment 3, a common outer arc edge end is formed for adjacent segments 10A4 and 20A4. Segment 10A4 includes endpoint C1 in segment 20A4, and segment 20A4 includes endpoint A1 in segment 10A4. Furthermore, segment 10A4 has an edge 10d4 defined by endpoints B1 and A1, and segment 20A4 has an edge 20d4 defined by endpoints D1 and C1. However, in this case, segments 10A4 and 20A4 have a common straight section AC1d. The straight section AC1d is formed by a straight line 20f connecting endpoint C1 and endpoint A1, and the straight line 20f substantially passes through an inflection point F.

[0060] The aforementioned curved arc edges AC1a, AC1c, or straight sections AC1b, AC1d can be applied, for example, to the outer arc edge Aab near one or both of the edges 10c, 10d of the arch-shaped segment 10A shown in Figure 3A, and to the outer arc edge Aab1 near the edge 10d of the partial arch-shaped segment 10B shown in Figure 3B. Furthermore, similar curved arc edges or straight sections may be applied to the outer arc edges Aab near both edges of the arch-shaped segment 10A, or any two different curved arc edges or straight sections may be applied.

[0061] Figure 7 shows an example of the configuration of segment 10A5 having different inflectional arc edges near both ends. As shown in the figure, the curvature circle C10a5 of the first arc shape 10a5 of segment 10A5 is externally tangent to circle C30a with radius of curvature r30A at inflection point Fa near the end edge 10c5 of segment 10A5, and externally tangent to circle C30b with radius of curvature r30A at inflection point Fb near the end edge 10d5. The outer arc edge Aab5 of segment 10A5 is configured to have an inflectional arc edge ACa near the end edge 10c5 that includes the endpoint C2a on circle C30a, and an inflectional arc edge ACb near the end edge 10d5 that includes the endpoint C1b on circle C30b. Here, the curved arc edge ACa can be formed in the same way as the curved arc edge AC1a shown in Figure 6A, and the curved arc edge ACb can be formed in the same way as the curved arc edge AC1c shown in Figure 6C. The segment 10A5 configured in this way has an outer arc edge that is slightly asymmetrical with respect to the center line n. Note that the outer arc edge of the arched segment according to this disclosure is not limited to the configuration example shown in Figure 7. For example, the outer arc edges near the end edges on both sides of the arched segment can be formed by any two combination of the curved arc edges AC1a, AC1c, or the straight sections AC1b, AC1d.

[0062] To reduce surface reflection to light of a given wavelength, wavelength conversion elements often have an anti-reflective coating applied to one surface of the segments constituting the element. By configuring the outer arc edge of the segment with a slightly asymmetrical shape, the surface with the anti-reflective coating can be easily identified, which is convenient when constructing a wavelength conversion wheel.

[0063] Figure 8 shows a simplified representation of adjacent segment rows 110B, 120B, and 130B in a plate-shaped sintered material 30. As shown in the figure, the arch-shaped segment rows 110B, 120B, and 130B, which are arranged in opposite directions with their edges touching each other, have generally similar shapes but are configured to differ in size. Furthermore, as shown in the enlarged view, in the end region S2 where adjacent segment rows touch, the outer arc edge 122a of arch-shaped segment 122B and the outer arc edge 132a of the adjacent arch-shaped segment 132B have overlapping common outer arc edge ends, which include a curved arc edge portion or a straight portion (not shown) at the outer arc edge ends that touch each other. This allows segments of adjacent segment rows to be separated along a common cutting line, thereby shortening the cutting distance when separating individual segments.

[0064] In this way, by configuring arched segments or partially arched segments with a common outer arc edge end that includes a curved arc edge or a straight section, segments of adjacent segment rows can be separated along a common cutting line, and the cutting distance when separating individual segments can be shortened, thereby improving production efficiency and yield. Furthermore, it becomes possible to simultaneously manufacture segments of similar shape but different sizes on a single plate-shaped sintered material, improving productivity and enabling flexible production of various light sources or projector devices.

[0065] The arch-shaped segment or partial arch-shaped segment of this disclosure can be used to configure, for example, a wavelength conversion wheel for a projection-type image display device. The configuration of the wavelength conversion wheel 1 according to Embodiment 3 will be described below with reference to Figures 9-10D.

[0066] <Configuration of the wavelength conversion wheel> (Embodiment 2) Figure 9 is a side view showing an example of the configuration of the wavelength conversion wheel 1 according to Embodiment 3 of this disclosure. Figures 10A to 10D are schematic plan views showing example planar configurations of the wavelength conversion wheels 1A-1D according to Examples 1 to 4 of Embodiment 3, and a modified example of Example 1 and Example 2 (Figures 10A1 and 10B1). In each figure, the plane on which the wavelength conversion wheel receives excitation light is defined as the XY plane, and the direction perpendicular to the XY plane is defined as the Z direction. Furthermore, in Figure 9, the configuration of the wavelength conversion wheels 1A-1D shown in Figures 10A to 10D in the common YZ plane will be described as the wavelength conversion wheel 1.

[0067] As shown in Figure 9, the wavelength conversion wheel 1 comprises a substrate 11, a wavelength conversion element 12 arranged on the substrate 11, and a motor 5 that rotates the substrate 11. The wavelength conversion wheel 1 of this embodiment can be used, for example, as a wavelength conversion wheel for a projection-type image display device.

[0068] The substrate 11 is made of aluminum, for example, and has a first main surface 11a and a second main surface 11b. The substrate 11 has a disc shape that can be rotated with respect to the central axis 11c of the substrate 11. A wavelength conversion element 12 is arranged on the first main surface 11a of the substrate 11. For example, a motor 5 is attached to the second main surface 11b of the substrate 11. Furthermore, a reflective film can be formed on the first main surface 11a of the substrate 11, and this reflective film can have the property of reflecting light in the wavelength band of the excitation light and light in the wavelength band of the wavelength conversion light generated by the excitation light.

[0069] The motor 5 rotates the disc-shaped substrate 11 around the central axis 11c, thereby suppressing the temperature rise of the wavelength conversion element 12 due to excitation light and stably maintaining the wavelength conversion efficiency.

[0070] The wavelength conversion element 12 includes a wavelength conversion material, such as a phosphor, which is excited by incident light and emits light of a different wavelength from the wavelength of the incident light. In this embodiment, inorganic phosphor particles can be used as the wavelength conversion material. Furthermore, the phosphor used as the wavelength conversion material is not particularly limited as long as it emits fluorescence in response to irradiation with excitation light. For example, oxide phosphors, nitride phosphors, oxynitride phosphors, sulfide phosphors, garnet-based compound phosphors, etc., can be used.

[0071] The wavelength conversion element 12 is fixed onto the first main surface 11a of the substrate 11 by an adhesive layer 13. The adhesive layer may be a mixed layer of a heat-resistant resin such as silicone or silsesquioxane filled with highly reflective particles. In this case, it will also function as a reflective layer. Alternatively, it may be a mixed layer of a heat-resistant resin such as silicone or silsesquioxane filled with highly thermally conductive particles. In this case, it will also function as a heat transfer layer. In this case, it has the effect of suppressing the temperature rise of the wavelength conversion material such as a phosphor. Furthermore, both highly reflective and highly thermally conductive particles may be mixed, or a heat-resistant resin such as silicone or silsesquioxane without any particles may be used.

[0072] In this embodiment, the wavelength conversion element 12 is composed of either an arch-shaped segment or a partially arch-shaped segment according to Embodiment 1 or Embodiment 2 described above. The wavelength conversion wheel 1 may include a plurality of wavelength conversion elements, and the plurality of wavelength conversion elements may include a wavelength conversion material that is excited by incident light and emits light of different wavelengths. In this embodiment, as shown in Figures 10A to 10D, the plurality of arch-shaped or partially arch-shaped wavelength conversion elements are arranged around the rotation axis of the substrate 11, in this embodiment, around the central axis 11c, with the concave side facing inward towards the substrate 11. Note that the wavelength conversion elements can be composed of segments of different shapes or central angles, and the number of wavelength conversion elements used can be changed depending on the application.

[0073] The wavelength conversion wheel 1A of Embodiment 1 shown in Figure 10A has wavelength conversion elements 12A1, 12A2, and 12A3, which are composed of arch-shaped segments. The first arc-shaped portions 10A1, 10A2, and 10A3 of the arch-shaped segments are arranged along a circumference 11A that is the same distance from the rotation axis of the substrate 11, and the wavelength conversion elements 12A1, 12A2, and 12A3 are arranged in a ring shape as a whole. The circumference that is the same distance from the rotation axis of the substrate 11 passes through the ends of the wavelength conversion elements, and adjacent wavelength conversion elements are arranged to be in contact with each other at their ends. The ring-shaped arrangement of wavelength conversion elements 12A1, 12A2, and 12A3 forms an annular excitation light irradiation region.

[0074] In a projection-type image display device, multiple wavelength conversion elements are arranged axially in a ring shape along the circumference where the first arc-shaped portion is the same distance from the rotation axis of the substrate. This arrangement suppresses vibrations of the wheel during rotation due to unbalance and stabilizes the wavelength conversion wheel. This disclosure is not limited to the boundary lines of the ends where adjacent wavelength conversion elements touch each other; the touching ends of adjacent wavelength conversion elements may have linear or curved boundaries.

[0075] In Figure 10A, the arch-shaped segments constituting the wavelength conversion elements 12A1, 12A2, and 12A3 are shown as the basic shape arch-shaped segment 10A according to Embodiment 1 of this disclosure (Figure 3A), but this disclosure is not limited thereto. For example, Figure 10A1 is a schematic plan view showing an example of a planar configuration of a wavelength conversion wheel 1Aa according to a modified example of Embodiment 1 shown in Figure 10A. The wavelength conversion elements 12Aa1, 12Aa2, and 12Aa3 of the wavelength conversion wheel 1Aa in Figure 10A1 can be composed of, for example, any of the arch-shaped segments 10A1 to 10A5, each having an outer arc edge end including a curved arc edge or a straight section according to Embodiment 2 of this disclosure (Figures 6A to 7). As shown in the figure, the wavelength conversion elements 12Aa1, 12Aa2, and 12Aa3 are arranged in a ring shape overall, with the first arc-shaped portions 10Aa1, 10Aa2, and 10Aa3 arranged along the circumference 11A which is the same distance from the rotation axis of the substrate 11. However, the endpoint C1A at the outer arc edge end, which includes the inflected arc edge portion or the straight portion, protrudes slightly from the circumference 11A. Furthermore, the wavelength conversion elements 12Aa1, 12Aa2, and 12Aa3, which thus have an endpoint C1A that protrudes slightly from the circumference 11A, can constitute a wavelength conversion wheel 1Aa with overall rotational symmetry.

[0076] The wavelength conversion wheel 1B of Embodiment 2 shown in Figure 10B has wavelength conversion elements 12B1-12B6, which are composed of partial arched segments. The partial arched segments are arranged in a ring shape overall, with first arc-shaped portions 10B1-10B6 along a circumference 11B that is the same distance from the rotation axis of the substrate 11. The circumference that is the same distance from the rotation axis of the substrate 11 passes through the ends of the wavelength conversion elements, and adjacent wavelength conversion elements are arranged to be in contact with each other at their ends. The ring-shaped arrangement of wavelength conversion elements 12B1-12B6 forms an annular excitation light irradiation region. In this embodiment, the partial arched segments constituting adjacent wavelength conversion elements are arranged to be in contact at ends with different radial widths of the circumference 11B, but the disclosure is not limited thereto. The partial arched segments constituting adjacent wavelength conversion elements may be in contact at ends with different radial widths, or they may be arranged to be in contact at ends with substantially the same radial width. Furthermore, the edges where adjacent wavelength conversion elements meet may have a linear boundary or a curved boundary.

[0077] In Figure 10B, the partial arched segments constituting the wavelength conversion elements 12B1-12B6 are shown as the basic shape partial arched segments 10B according to Embodiment 1 of this disclosure (Figure 3B), but this disclosure is not limited thereto. For example, Figure 10B1 is a schematic plan view showing an example of a planar configuration of a wavelength conversion wheel 1Ba according to a modification of Embodiment 2 shown in Figure 10B. The wavelength conversion elements 12Ba1-12Ba6 of the wavelength conversion wheel 1Ba in Figure 10B1 can be composed of, for example, any of the partial arched segments 10A1-10A5, each having an outer arc edge end including a curved arc edge or a straight section according to Embodiment 2 of this disclosure (Figures 6A-7). As shown in the figure, the wavelength conversion elements 12Ba1-12Ba6 are arranged in a ring shape overall, with the first arc-shaped portions 10Ba1-10Ba6 arranged along the circumference 11A at the same distance from the rotation axis of the substrate 11. However, the endpoint C1B at the outer arc edge end, which includes the inflected arc edge or the straight portion, protrudes slightly from the circumference 11A. Furthermore, the wavelength conversion elements 12Ba1-12Ba6, having endpoint C1B that protrudes slightly from the circumference 11A in this way, can constitute a wavelength conversion wheel 1Ba with overall rotational symmetry.

[0078] The wavelength conversion wheel shown in Figures 10A, 10A1 or 10B, 10B1 has multiple wavelength conversion elements arranged adjacent to each other in a ring shape, thereby enabling the continuous production of wavelength-converted light upon irradiation with incident excitation light. The multiple wavelength conversion elements of the wavelength conversion wheel can also be configured by a combination of arch-shaped segments and partial arch-shaped segments (not shown) according to this disclosure.

[0079] Multiple wavelength conversion elements arranged in a ring shape as a whole can include a missing portion where part of the ring is missing. For example, in a single-chip DLP projector, RGB color light is used in a time-division manner. In this type of projector, it is not necessary to constantly emit wavelength-converted light; the excitation light, which is blue light, can sometimes be used directly as illumination light. In this case, a wavelength conversion wheel composed of wavelength conversion elements arranged in a ring shape with a missing portion can be used.

[0080] The wavelength conversion wheel 1C of Embodiment 3 shown in Figure 10C is configured to have first wavelength conversion elements 12C1a, 12C1b and second wavelength conversion elements 12C2a, 12C2b. The first wavelength conversion elements 12C1a, 12C1b and the second wavelength conversion elements 12C2a, 12C2b are arranged in a ring shape overall, with the first arc-shaped portions 10C1a, 10C1b, 10C2a, 10C2b of their respective arch-shaped segments arranged along a circumference 11C that is the same distance from the rotation axis of the substrate 11. Furthermore, the first wavelength conversion elements 12C1a, 12C1b include a first wavelength conversion material that converts excitation light to light of a first wavelength, and the second wavelength conversion elements 12C2a, 12C2b may include a second wavelength conversion material that converts excitation light to light of a second wavelength.

[0081] In this embodiment, as shown in the figure, the first wavelength conversion element 12C1a and the second wavelength conversion element 12C2a are arranged so that they are in contact with each other at one end, and the first wavelength conversion element 12C1b and the second wavelength conversion element 12C2b are arranged so that they are in contact with each other at one end. At the other end of the first wavelength conversion element 12C1a and the second wavelength conversion element 12C2b, and at the other end of the second wavelength conversion element 12C2a and the first wavelength conversion element 12C1b, they are not in contact with each other, and a ring-shaped gap is formed. The substrate 11 is provided with openings 15a and 15b corresponding to the gaps of the wavelength conversion elements. As shown in Figure 10C, the wavelength conversion elements 12C1a, 12C1b, 12C2a, and 12C2b, which are arranged in a ring shape with a portion missing, and the openings 15a and 15b together form an annular excitation light irradiation region, and excitation light can be transmitted through the openings 15a and 15b.

[0082] In the configuration example shown in Figure 10C, two openings are provided, but the disclosure is not limited thereto. There may be one opening or two or more openings. Furthermore, the first wavelength conversion elements 12C1a, 12C1b and the second wavelength conversion elements 12C2a, 12C2b can be composed of either arch-shaped segments or partially arch-shaped segments according to Embodiment 1 or Embodiment 2 described above. In addition, each wavelength conversion element may be composed of segments with similar shapes or central angles, or it may be composed of segments with different shapes or central angles.

[0083] The wavelength conversion wheel 1D of Embodiment 4 shown in Figure 10D is configured to have first wavelength conversion elements 12D1a and 12D1b and second wavelength conversion elements 12D2a and 12D2b. The first wavelength conversion elements 12D1a and 12D1b include a first wavelength conversion material that converts excitation light to light of a first wavelength, and the second wavelength conversion elements 12D2a and 12D2b may include a second wavelength conversion material that converts excitation light to light of a second wavelength.

[0084] As shown in Figure 10D, the wavelength conversion wheel 1D differs from the wavelength conversion wheel 1C of the previously described embodiment 3 in that it has reflective regions 16a and 16b instead of the apertures 15a and 15b of the wavelength conversion wheel 1C. As shown in the figure, the wavelength conversion elements 12D1a, 12D2a, 12D1b, and 12D2b are arranged adjacent to each other in a ring shape. A reflective film is applied to a part of the ring-shaped wavelength conversion elements 12D1a and 12D1b, forming reflective regions 16a and 16b. Excitation light can be reflected in the reflective regions 16a and 16b.

[0085] The first wavelength conversion elements 12D1a, 12D1b constituting the wavelength conversion wheel 1D include a first wavelength conversion material that converts excitation light to light of a first wavelength, and the second wavelength conversion elements 12D2a, 12D2b may include a second wavelength conversion material that converts excitation light to light of a second wavelength. In addition, although the configuration example shown in Figure 10D has two reflection regions, this disclosure is not limited thereto. There may be one reflection region or two or more. Furthermore, the first wavelength conversion elements 12D1a, 12D1b and the second wavelength conversion elements 12D2a, 12D2b can be composed of either an arch-shaped segment or a partially arch-shaped segment according to Embodiment 1 or Embodiment 2 described above. Furthermore, each wavelength conversion element may be composed of segments with similar shapes or central angles, or of different shapes or central angles.

[0086] Furthermore, although not shown in Figure 10D, the multiple wavelength conversion elements constituting the wavelength conversion wheel 1D can be arranged in a ring shape with a portion missing. In this case, reflective regions 16a and 16b can be formed by applying a reflective film to the first main surface 11a of the substrate 11 at positions corresponding to the missing portion in the ring shape.

[0087] In Figure 10D, the reflection regions 16a and 16b are shown to be located in approximately the same positions as the apertures 15a and 15b of the wavelength conversion wheel 1C in Embodiment 3, but this is not limited to this. Also, the reflection regions 16a and 16b are not limited to two; there may be only one, or there may be two or more. Furthermore, the first wavelength conversion elements 12D1a and 12D1b and the second wavelength conversion elements 12D2a and 12D2b can be composed of either arch-shaped segments or partially arch-shaped segments according to Embodiment 1 or Embodiment 2 described above. Each wavelength conversion element may be composed of segments with similar shapes or central angles, or it may be composed of segments with different shapes or central angles.

[0088] According to the wavelength conversion wheels 1A-1D in the embodiment of Embodiment 3, and the wavelength conversion wheels 1Aa,1Ba in the modified embodiment, by using a wavelength conversion element composed of an arch-shaped segment or a partially arch-shaped segment according to Embodiment 1 or Embodiment 2, it is possible to improve production efficiency and yield.

[0089] <Configuration of the light source device and projection-type image display device> (Embodiment 4) The configuration of the light source device and projection-type image display device according to Embodiment 4 will be described below with reference to Figures 11 and 12. Figure 11 is a diagram showing an example configuration of the light source device 51A according to Embodiment 4 of this disclosure. Figure 12 is a diagram showing an example configuration of the projection-type image display device 101A equipped with the light source device 51A shown in Figure 11.

[0090] Embodiment 4 is a light source device 51A using the wavelength conversion wheels 1A, 1Aa or 1B, 1Ba of Embodiment 3, and a projection-type image display device 101A using the light source device 51A. In the following description, the wavelength conversion wheel of the light source device 51A will be referred to as wavelength conversion wheel 1. A detailed explanation of wavelength conversion wheel 1 will be omitted.

[0091] The light source device 51A of Embodiment 4 can be used, for example, in a 3-chip projection-type image display device. As shown in Figure 11, blue wavelength laser light emitted from multiple laser light sources 901 is collimated by multiple collimator lenses 902 provided corresponding to each of the laser light sources 901. The collimated blue light is incident on a subsequent convex lens 903, reducing its beam width, and then incident on a subsequent diffuser plate 904 where it is diffused and the uniformity of the light is improved. The blue light with improved uniformity is then incident on a subsequent concave lens 905 and is made into a parallel beam.

[0092] The blue light, parallelized by the concave lens 905, is incident on the spectrally characteristic mirror 906, which is positioned at approximately 45 degrees with respect to the optical axis, and continues to be incident on the subsequent convex lens 907 without changing the direction of light propagation. The spectrally characteristic mirror 906 has spectral properties that allow light in the wavelength range of blue light emitted from the laser light source 901 and the laser light source 921 to pass through, and reflect light in the wavelength range of wavelength-converted light that is wavelength-converted by the wavelength-converting wheel 1 using the blue light from the laser light source 901 as excitation light.

[0093] Here, the spectrally characteristic mirror 906 is assumed to have spectral characteristics that focus on the wavelength characteristics of the blue light from the laser light source and the wavelength-converted light. However, by focusing on the polarization direction of the laser light source and adjusting the polarization direction of the blue light from the laser light source to the same direction, the mirror may be made to have spectral characteristics that focus on the wavelength characteristics of the wavelength-converted light that passes through the blue light in a specific polarization direction from the laser light source and is wavelength-converted.

[0094] The blue light incident on the convex lens 907, in combination with the subsequent convex lens 908, is incident on the annular excitation light irradiation region (see Figures 10A and 10B) formed by the wavelength conversion element 12 in the subsequent wavelength conversion wheel 1. The wavelength conversion wheel 1 is fitted with a motor 5, and the blue excitation light focused by the convex lenses 907 and 908 is arranged to be incident on the wavelength conversion element 12, which is arranged in a ring shape around the rotation axis of the wavelength conversion wheel 1.

[0095] The blue light focused onto the wavelength conversion element 12 of the wavelength conversion wheel 1 by the convex lenses 907 and 908 undergoes wavelength conversion and changes its direction of propagation by 180 degrees. It then enters the convex lenses 908 and 907 in that order again, becoming parallel light. The wavelength range of the light converted here is optimized so that it can be combined with the blue light emitted from the laser light source 921 (described later) to form, for example, white light.

[0096] The wavelength-converted light, which is emitted from the convex lens 907 and made into parallel light, is incident on the spectral mirror 906 from the opposite direction. As mentioned above, the spectral mirror 906 has the property of reflecting light in the wavelength range of the wavelength-converted light, so it changes the direction of propagation of the light by 90 degrees. The wavelength-converted light, whose direction of propagation has been changed by 90 degrees by the spectral mirror 906, is then incident on the subsequent convex lens 909.

[0097] Furthermore, the blue wavelength laser light emitted from the multiple laser light sources 921 is collimated by multiple collimator lenses 922, which are arranged corresponding to each of the laser light sources 921. The collimated blue light is incident on the subsequent convex lens 923, reducing its beam width, and then incident on the subsequent diffuser plate 924, where it is diffused and the uniformity of the light is improved. The blue light with improved uniformity is then incident on the subsequent concave lens 925, where it is made into a parallel beam.

[0098] The blue light parallelized by the concave lens 925 has the characteristic of passing through light in the wavelength range of blue light emitted from the laser light source 921. It is incident on the spectrally characteristic mirror 906, which is positioned at approximately 45 degrees with respect to the optical axis, and is incident on the subsequent convex lens 909 without changing the direction of light propagation.

[0099] The wavelength-converted light from the wavelength-converting wheel 1 and the blue light from the laser light source 921, which are incident on the convex lens 909, are focused and incident on the rod integrator 910, whose incident end is positioned approximately at the focal point of the convex lens 909. The light beam, which has been made uniform in the rod integrator 910, is emitted from the exit end of the rod integrator 910.

[0100] In Embodiment 4 shown in Figure 11, the spectral characteristic mirror 906 is positioned at an angle of approximately 45 degrees to the optical axis. However, in order to maximize its spectral characteristics, the angle of the spectral characteristic mirror 906 with respect to the optical axis may be different from approximately 45 degrees, in which case other components may be positioned to match that angle.

[0101] Furthermore, although Figure 11 describes the spectrally characteristic mirror 906 as having the characteristic of transmitting light in the wavelength range of blue light and reflecting light in the wavelength range of wavelength-converted light, the arrangement of other components may be optimized as appropriate to have the characteristic of reflecting light in the wavelength range of blue light and transmitting light in the wavelength range of wavelength-converted light.

[0102] Furthermore, the laser light from the laser light source 901 may be in the ultraviolet region, rather than being in the blue light wavelength range. In that case, the characteristics of the spectrally characteristic mirror 906 and the arrangement of other components should be optimized to match the wavelength range of the laser light from the laser light source 901.

[0103] Next, with reference to Figure 12, the configuration of the projection-type image display device 101A using the light source device 51A with the wavelength conversion wheel 1 will be described. The projection-type image display device 101A in this embodiment is a so-called 3-chip type projection-type image display device.

[0104] The light emitted from the rod integrator 910 is mapped to the DMD (Digital Micromirror Device) 1041, 1042, and 1043, which act as light modulation units, by a relay lens system consisting of convex lenses 1031, 1032, and 1033.

[0105] Light emitted from the relay lens system, composed of convex lenses 1031, 1032, and 1033, enters a total internal reflection prism 1034 with a small gap 1035. Light emitted from the relay lens system and incident on the total internal reflection prism 1034 at an angle greater than or equal to the total internal reflection angle is reflected by the small gap 1035, changing the direction of light propagation, and enters a color prism 1036 composed of three glass blocks with a small gap 1037.

[0106] The blue light from the total internal reflection prism 1034 and the wavelength-converted light incident on the first glass block of the color prism 1036 is first reflected by a spectrally characteristic reflective film having blue reflection properties, which is provided in front of the minute gap 1037. This changes its direction of propagation, and it proceeds to the total internal reflection prism, where it is incident on the minute gap between the total internal reflection prism 1034 and the color prism 1036 at an angle greater than the total internal reflection angle, and then incident on the DMD 1043 which displays a blue image.

[0107] Next, the red light from the wavelength-converted light that has passed through the minute gap is reflected by a spectrally reflective film located between the second and third glass blocks of the color prism 1036, which has spectral properties that reflect light in the red wavelength region and allow green light to pass through, and changes its direction of propagation toward the first glass block.

[0108] The red light, whose direction of propagation has been changed, is reflected again by a small gap 1037 between the first and second glass blocks of the color prism 1036, and its direction of propagation is changed before it enters the red DMD 1042.

[0109] Furthermore, the green light from the wavelength-converted light that passes through the minute gap reflects the red wavelength light provided between the second and third glass blocks of the color prism, passes through a spectrally characteristic reflective film that has spectral properties that allow green light to pass through, proceeds directly to the third glass block, and then enters the green DMD1041.

[0110] DMD1041, 1042, and 1043 change the direction of light propagation by changing the direction of the mirror for each pixel according to the video signal of each color, from a video circuit (not shown).

[0111] The green light, whose direction of propagation has been changed according to the video signal by the green DMD1041, enters the third glass block of the color prism 1036 and passes through a spectrally characteristic reflective film provided between the third and second glass blocks of the color prism 1036.

[0112] The red light, whose direction of propagation has been changed according to the video signal by the red DMD1042, enters the second glass block of the color prism 1036 and is reflected by entering the minute gap 1037 provided between the second and first glass blocks of the color prism 1036 at an angle greater than the total reflection angle. Subsequently, the red light changes direction of propagation to the third glass block of the color prism, is reflected by a spectrally characteristic reflective film provided between the second and third glass blocks of the color prism 1036, changes direction of propagation of that light, and is combined with green light.

[0113] Light synthesized by the spectrally characteristic reflective film travels towards the first glass block side of the color prism 1036 and is transmitted by being incident at an angle less than or equal to the total reflection angle into the minute gap 1037 provided between the second and first glass blocks of the color prism 1036.

[0114] Furthermore, the blue light, whose direction of propagation has been changed according to the video signal by the blue DMD1043, enters the first glass block of the color prism 1036, travels towards the total internal reflection prism 1034, and enters the gap between the total internal reflection prism 1034 and the color prism 1036 at an angle greater than the total internal reflection angle, thereby traveling towards the second glass block of the color prism 1036. Subsequently, the blue light is reflected by the spectrally characteristic reflective film provided on the first glass block side in front of the minute gap 1037 provided between the first and second glass blocks of the color prism 1036, changing its direction of propagation towards the total internal reflection prism 1034, where it is combined with the light from the green DMD1041 and the red DMD1042, and enters the total internal reflection prism 1034.

[0115] Light from DMDs 1041, 1042, and 1043, incident on the total internal reflection prism 1034, passes through the prism 1034, enters the projection lens 1051 which is part of the projection optical system, and illuminates an object (not shown) to be projected.

[0116] According to the light source device 51A and projection-type image display device 101A of Embodiment 4, by using wavelength conversion wheels 1A, 1Aa (see Figures 10A and 10A1) composed of arch-shaped segments, or wavelength conversion wheels 1B, 1Ba (see Figures 10B and 10B1) composed of partial arch-shaped segments, production efficiency and yield can be improved.

[0117] (Embodiment 5) The configuration of the light source device and projection-type image display device according to Embodiment 5 will be described below with reference to Figures 13 and 14. Figure 13 is a diagram showing an example configuration of the light source device 51B according to Embodiment 5 of this disclosure. Figure 14 is a diagram showing an example configuration of the projection-type image display device 101B equipped with the light source device 51B shown in Figure 13.

[0118] Embodiment 5 is a light source device 51B using the wavelength conversion wheel 1A or wavelength conversion wheel 1B of Embodiment 3, and a projection-type image display device 101B using the light source device 51B. In the following description, the wavelength conversion wheel of the light source device 51B will be described as wavelength conversion wheel 1. A detailed description of wavelength conversion wheel 1 will be omitted.

[0119] Embodiment 5, the projection-type image display device 101B, uses an active-matrix transmissive liquid crystal panel as an image forming means, in either TN (Twisted Nematic) mode or VA (Vertical Alignment) mode, in which thin-film transistors are formed in the pixel region.

[0120] As shown in Figure 13, the light source device 51B consists of a blue semiconductor laser 116, a blue solid-state light source unit 119, lenses 126 and 127, a first diffuser plate 128, a first phase difference plate 129, a polarization separation and color separation mirror 130, convex lenses 131 and 132, a quarter-wave plate 137 which is a second phase difference plate, a condenser lens 138, a second diffuser plate 139, a mirror 140, and a wavelength conversion wheel 1.

[0121] Blue light emitted from a blue solid-state light source unit 119, which consists of multiple sets of blue semiconductor lasers 116 and corresponding collimator lenses, has its beam width reduced by a convex lens 126, then parallelized by a concave lens 127, and finally homogenized by a first diffuser plate 128. Subsequently, a first phase difference plate 129 rotates the polarization direction of the blue light emitted from the aforementioned blue solid-state light source unit 119, thereby adjusting the ratio of blue light to fluorescent light in the white light realized by the subsequent optical system. The light emitted from the aforementioned first phase difference plate 129 is incident on a polarization separation and color separation mirror 130, which is positioned at approximately 45 degrees with respect to the optical axis.

[0122] The polarization-separating and color-separating mirror 130 has the characteristic of transmitting the P-polarized light of the aforementioned blue semiconductor laser 116 and the wavelength-converted light emitted by the wavelength conversion wheel 1 described later, which converts the light in the wavelength range of the blue semiconductor laser 116, and reflecting the S-polarized light of the aforementioned blue semiconductor laser 116.

[0123] Of the light emitted from the blue solid-state light source unit 119 that is incident on the polarization and color separation mirror 130, the S-polarized blue light is reflected, changes its direction of propagation, and is incident on the convex lens 131. The incident blue light, in combination with the convex lens 131 and the subsequent convex lens 132, is incident on the annular excitation light irradiation region (see Figures 10A and 10B) formed by the wavelength conversion element 12 in the subsequent wavelength conversion wheel 1. The wavelength conversion wheel 1 is fitted with a motor 5, and the blue excitation light focused by the convex lenses 131 and 132 is arranged to be incident on the wavelength conversion element 12 which is arranged in a ring shape around the rotation axis of the wavelength conversion wheel 1.

[0124] The blue light focused onto the wavelength conversion element 12 of the wavelength conversion wheel 1 by the convex lenses 131 and 132 undergoes wavelength conversion and changes its direction of propagation by 180 degrees. It then enters the convex lenses 132 and 131 in that order, becomes parallel light, and enters the polarization separation and color separation mirror 130.

[0125] Furthermore, of the light emitted from the blue solid-state light source unit 119 that is incident on the polarization and color separation mirror 130, the P-polarized light passes through the polarization and color separation mirror 130 and is incident on the quarter phase difference plate 137, where the linearly polarized light is converted to circularly polarized light. Subsequently, the circularly polarized blue light passes through the convex lens 138 and the diffuser plate 139 and is focused onto the mirror 140. The light reflected by the mirror 140 passes through the diffuser plate 139 and is incident on the convex lens 138, where it is converted to parallel light. The light emitted from the convex lens 138 is incident on the quarter phase difference plate 137 again and is converted from circularly polarized light to S-polarized light.

[0126] The S-polarized blue laser light emitted from the 1 / 4 phase difference plate 137 enters the polarization separation and color separation mirror, changing its direction of travel by 90 degrees, and combines with the wavelength-converted light from the aforementioned wavelength conversion wheel 1 to emit white light.

[0127] Light emitted from the light source device 51B is incident on the projection lens 224 via an optical system consisting of a first lens array plate 200, a second lens array plate 201, a polarization conversion element 202, a superposition lens 203, a blue-reflecting dichroic mirror 204, a green-reflecting dichroic mirror 205, reflective mirrors 206, 207, 208, relay lenses 209, 210, field lenses 211, 212, 213, incident polarizers 214, 215, 216, liquid crystal panels 217, 218, 219, outgoing polarizers 220, 221, 222, and a color-combining prism 223 composed of a red-reflecting dichroic mirror and a blue-reflecting dichroic mirror.

[0128] White light from the light source device 51B is incident on a first lens array plate 200, which is composed of multiple lens elements. The light beam incident on the first lens array plate 200 is divided into many light beams. The divided many light beams converge on a second lens array plate 201, which is composed of multiple lenses. The lens elements of the first lens array plate 200 have aperture shapes similar to those of the liquid crystal panels 217, 218, and 219. The focal lengths of the lens elements of the second lens array plate 201 are determined so that they are approximately conjugate to those of the first lens array plate 200 and the liquid crystal panels 217, 218, and 219. The light emitted from the second lens array plate 201 is incident on a polarization conversion element 202.

[0129] The polarization conversion element 202 is composed of a polarization separation prism and a half-wave plate, and converts natural light from a light source into light with a single polarization direction. Since the wavelength-converted light is natural light, it is polarized in a single polarization direction, but blue light is incident as S-polarized light and is therefore converted to P-polarized light. The light from the polarization conversion element 202 is incident on the superposition lens 203. The superposition lens 203 is a lens for superimposing illumination onto the liquid crystal panels 217, 218, and 219 with light emitted from each lens element of the second lens array plate 201. The first lens array plate 200, the second lens array plate 201, the polarization conversion element 202, and the superposition lens 203 constitute the illumination optical system.

[0130] Light from the superimposing lens 203 is separated into blue, green, and red light by the blue-reflecting dichroic mirror 204 and the green-reflecting dichroic mirror 205, which are color separation means. The green light passes through the field lens 211 and the incident polarizer 214 and enters the liquid crystal panel 217. The blue light is reflected by the reflective mirror 206, then passes through the field lens 212 and the incident polarizer 215 and enters the liquid crystal panel 218. The red light is transmitted, refracted, and reflected by the relay lenses 209 and 210 and the reflective mirrors 207 and 208, then passes through the field lens 213 and the incident polarizer 216 and enters the liquid crystal panel 219.

[0131] Three liquid crystal panels 217, 218, and 219 change the polarization state of incident light by controlling the voltage applied to the pixels according to the video signal. By combining the incident polarizers 214, 215, and 216 and the exit polarizers 220, 221, and 222, which are arranged on both sides of each liquid crystal panel 217, 218, and 219 with their transmission axes perpendicular to each other, the light is modulated to form green, blue, and red images. The light of each color that has passed through the exit polarizers 220, 221, and 222 is reflected by a color combining prism 223, where the red and blue light are reflected by a red-reflecting dichroic mirror and a blue-reflecting dichroic mirror, respectively, and combined with the green light before entering the projection lens 224. The light that enters the projection lens 224 is magnified and projected onto a projection target such as a screen (not shown).

[0132] According to the light source device 51B and projection-type image display device 101B of Embodiment 5, by using a wavelength conversion wheel 1A (see Figure 10A) composed of arch-shaped segments, or a wavelength conversion wheel 1B (see Figure 10B) composed of partially arch-shaped segments, production efficiency and yield can be improved.

[0133] (Embodiment 6) The configuration of the light source device and projection-type image display device according to Embodiment 6 will be described below with reference to Figures 15 and 16. Figure 15 is a diagram showing an example configuration of the light source device 51C according to Embodiment 6 of this disclosure. Figure 16 is a diagram showing an example configuration of the projection-type image display device 101C equipped with the light source device 51C shown in Figure 15.

[0134] Embodiment 6 is a light source device 51C using the wavelength conversion wheel 1C of Embodiment 3, and a projection-type image display device 101C using the light source device 51C. In the following description, a detailed explanation of the wavelength conversion wheel 1C will be omitted.

[0135] The light source device 51C of Embodiment 6 is, for example, a light source device for a single-chip projection-type image display device. As shown in Figure 15, blue wavelength laser light emitted from a plurality of laser light sources 1101 is collimated by a plurality of collimator lenses 1102 provided corresponding to each of the laser light sources 1101. The collimated blue light is incident on a subsequent convex lens 1103, where its beam width is reduced, and then incident on a subsequent diffuser plate 1104, where it is diffused to improve the uniformity of the light. The blue light with improved uniformity is then incident on a subsequent concave lens 1105, where it is made into a parallel beam.

[0136] The blue light, parallelized by the concave lens 1105, is incident on the spectrally characteristic mirror 1106, which is positioned at approximately 45 degrees with respect to the optical axis. The direction of light propagation is then changed by 90 degrees, and it is incident on the subsequent convex lens 1107. The spectrally characteristic mirror 1106 has spectral properties that reflect light in the wavelength range of blue light emitted from the laser light source 1101, and allow light in the wavelength range of light that is wavelength-converted using the blue light from the laser light source 1101 as excitation light by the wavelength conversion wheel 1C to pass through.

[0137] In this document, the spectrally characteristic mirror 1106 is assumed to have spectral characteristics that focus on the wavelength characteristics of the blue light from the laser light source and the wavelength-converted light. However, by focusing on the polarization direction of the laser light source and adjusting the polarization direction of the blue light from the laser light source to the same direction, the mirror may be made to have spectral characteristics that focus on the wavelength characteristics of the wavelength-converted light that passes through the light in the wavelength range and polarization direction of the blue light from the laser light source.

[0138] The blue light incident on the convex lens 1107, in combination with the subsequent convex lens 1108, is incident on an annular excitation light irradiation region (see Figure 10C) formed by the wavelength conversion element and aperture of the subsequent wavelength conversion wheel 1C. Since the wavelength conversion wheel 1C rotates around its axis of rotation, the blue excitation light focused by the convex lenses 1107 and 1108 can alternately be incident on the wavelength conversion element and aperture.

[0139] The blue light focused onto the wavelength conversion element of the wavelength conversion wheel 1C by the convex lenses 1107 and 1108 is wavelength-converted into wavelength-converted light, and its direction of propagation is changed by 180 degrees. It is then incident on the convex lenses 1108 and 1107 in that order again, and is made into parallel light. The wavelength-converted light here is combined with the blue light emitted from the laser light source 1101 to optimize its wavelength range so that it forms, for example, white light.

[0140] The wavelength-converted light, which is emitted from the convex lens 1107 and made into parallel light, is then incident again on the spectrally characteristic mirror 1106. As mentioned above, the spectrally characteristic mirror 1106 has the property of transmitting light in the wavelength range of the wavelength-converted light, so the light passes through without changing its direction.

[0141] Next, the blue light from the laser light source 1101, focused at the aperture of the wavelength conversion wheel 1C, passes through the wavelength conversion wheel 1C and is then parallelized by the subsequent convex lenses 1121 and 1122. Subsequently, a relay lens system consisting of three reflective mirrors 1123, 1125, and 1127 and three convex lenses 1124, 1126, and 1128 guides the light to the spectrally characteristic mirror 1106 so that it is parallelized and incident from a direction 180 degrees opposite to the direction in which the light from the laser light source 1101 is incident. Note that while a relay optical system is configured with three mirrors and three convex lenses here, other configurations are acceptable as long as they have similar performance.

[0142] Blue light entering the spectrally characteristic mirror 1106 from the convex lens 1128 is reflected after its direction of propagation is changed by 90 degrees.

[0143] With the above configuration, the wavelength-converted light and blue light combined by the spectrally characteristic mirror 1106 are time-resolved and incident on the convex lens 1109.

[0144] The wavelength-converted light and blue light, which are split when incident from the spectrally characteristic mirror 1106 to the convex lens 1109, are focused by the subsequent convex lens 1109 and incident on the subsequent color-filtered wheel 1110. The color-filtered wheel 1110 is synchronized with the wavelength-converting wheel 1C using a synchronization circuit (not shown), and is composed of multiple filters that transmit a portion or all of the wavelength range of the blue light and wavelength-converted light, in accordance with the characteristics of the optical system.

[0145] For example, during the period when yellow wavelength-converted light is emitted from the wavelength-converting wheel 1C, the wheel 1110 with a color filter rotates synchronously, having at least one region among those that transmit the wavelength range of the wavelength-converted light as is, a region that reflects the red portion of the wavelength-converted light and transmits green light, and a region that reflects the green portion of the wavelength-converted light and transmits red light. Furthermore, the region that transmits the wavelength range of the wavelength-converted light as is corresponds to the blue light that has passed through the aperture of the wavelength-converting wheel 1C, so that colored light with different wavelength ranges of light is focused in a time series near the incident end of the rod integrator 1111.

[0146] Light incident on the rod integrator 1111 is homogenized by the rod integrator 1111, and the homogenized light is emitted from its output end.

[0147] In Embodiment 6, the wheel with color filter 1110 is positioned in front of the rod integrator 1111, but it may also be positioned after the rod integrator 1111.

[0148] The projection-type image display device 101C of Embodiment 6 is, for example, a single-chip projection-type image display device, as shown in Figure 16. The projection-type image display device 101C includes a light source device 51C.

[0149] The light emitted from the rod integrator 1111 is mapped to the DMD 1241, which will be described later, by a relay lens system consisting of convex lenses 1231, 1232, and 1233.

[0150] Light that passes through convex lenses 1231, 1232, and 1233 and enters the total internal reflection prism 1234 enters the minute gap 1235 of the total internal reflection prism 1234 at an angle greater than the total internal reflection angle, and is reflected, changing the direction of light propagation before entering the DMD 1241.

[0151] The DMD1241 changes the direction of light propagation by changing the direction of a minute mirror in response to a signal from an image circuit (not shown) that is synchronized with the color light emitted by the combination of the wavelength conversion wheel 1C and the color filter wheel 1110, and then emits the light.

[0152] The light whose direction of propagation has been changed in response to the video signal in the DMD1241 enters the total internal reflection prism 1234, and enters the minute gap 1235 of the total internal reflection prism 1234 at an angle less than or equal to the total internal reflection angle. Thereafter, the light is transmitted directly to the projection lens 1251 and projected onto an object (not shown).

[0153] According to the light source device 51C and projection-type image display device 101C of Embodiment 6, by using a wavelength conversion wheel 1C (see Figure 10C) composed of arch-shaped segments or partially arch-shaped segments, it is possible to improve production efficiency and yield.

[0154] (Embodiment 7) The configuration of the light source device and projection-type image display device according to Embodiment 7 will be described below with reference to Figures 17 and 18. Figure 17 is a diagram showing an example configuration of the light source device 51D according to Embodiment 7 of this disclosure. Figure 18 is a diagram showing an example configuration of the projection-type image display device 101D equipped with the light source device 51D shown in Figure 17.

[0155] Embodiment 7 is a light source device 51D using the wavelength conversion wheel 1D of Embodiment 3, and a projection-type image display device 101D using the light source device 51D. In the following description, a detailed explanation of the wavelength conversion wheel 1D will be omitted.

[0156] The light source device 51D of Embodiment 7 is, for example, a light source device for a single-chip projection-type image display device. As shown in Figure 17, blue wavelength laser light emitted from multiple laser light sources 1201 is collimated by multiple collimator lenses 1202 provided corresponding to each of the laser light sources 1201. The collimated blue light is incident on a subsequent convex lens 1203, reducing its beam width, and then incident on a subsequent diffuser plate 1204 where it is diffused, improving the uniformity of the light. The blue light whose uniformity has been improved by the diffuser plate 1204 is incident on a subsequent concave lens 1205, where it is made into a parallel beam.

[0157] Furthermore, with the concave lens 1205 emitted, the optical system up to the concave lens 1205 is adjusted so that the polarization direction of the laser light becomes S-polarization with respect to the polarization and color separation / combination mirror 1206, which will be described later.

[0158] The blue light, which has been parallelized by the concave lens 1205, is incident on the polarization and color separation and synthesis mirror 1206, which is positioned at approximately 45 degrees with respect to the optical axis, changing the direction of light propagation by 90 degrees, and then incident on the subsequent λ / 4 wave plate 1207. The polarization and color separation and synthesis mirror 1206 has spectral characteristics that reflect S-polarized light in the blue wavelength range emitted from the laser light source 1201, and also passes P-polarized light in the blue wavelength range emitted from the laser light source 1201, as well as light in the wavelength range of the light whose wavelength has been converted by the excitation light from the laser light source 1201 using the wavelength conversion wheel 1D.

[0159] The polarization direction of the blue light from the laser light source 1201 incident on the λ / 4 wave plate 1207 is rotated to change it to circularly polarized light.

[0160] Light emitted from the λ / 4 wave plate 1207 enters the convex lens 1208 and, in combination with the subsequent convex lens 1209, enters the annular excitation light irradiation region (see Figure 10D) formed by the wavelength conversion element and reflection region of the subsequent wavelength conversion wheel 1D. Because the wavelength conversion wheel 1D rotates around its axis of rotation, the blue excitation light focused by the convex lenses 1208 and 1209 can alternately enter the wavelength conversion element and reflection region.

[0161] The blue light focused by the convex lenses 1208 and 1209 onto the wavelength conversion element of the wavelength conversion wheel 1D (see Figure 10D) is converted into wavelength-converted light, and its direction of propagation is changed by 180 degrees before it is incident on the convex lenses 1209 and 1208 again in that order, resulting in a parallel beam. The light whose wavelength is converted by the wavelength conversion wheel 1D is optimized in its respective wavelength range so that it is combined with the blue light emitted from the laser light source 1201 to form white light.

[0162] The wavelength-converted light, parallelized by the convex lens 1208 and emitted, passes through the λ / 4 wave plate 1207 and is again incident on the polarization and color separation and synthesis mirror 1206, which is positioned at a 45-degree angle to the optical axis. As mentioned above, the polarization and color separation and synthesis mirror 1206 has the characteristic of transmitting light in the wavelength range of the wavelength-converted light, so it passes the wavelength-converted light without changing the direction of the light, and the wavelength-converted light is incident on the subsequent convex lens 1210.

[0163] On the other hand, the blue light from the laser light source 1201, which is focused into the reflection region of the wavelength conversion wheel 1D (see Figure 10D), is reflected by the reflection region of the wavelength conversion wheel 1D, changes its direction of propagation by 180 degrees, and is incident on the convex lenses 1209 and 1208 in that order, becoming a parallel beam.

[0164] The blue light, which has been parallelized by the convex lenses 1209 and 1208, is incident on the subsequent λ / 4 wave plate 1207, where its polarization direction is rotated, and it is converted to P-polarized light before being emitted.

[0165] P-polarized light in the blue wavelength range emitted from the λ / 4 wave plate 1207 is incident on the polarization and color separation and synthesis mirror 1206, which is positioned at approximately a 45-degree angle to the optical axis. The polarization and color separation and synthesis mirror 1206 has the characteristic of reflecting S-polarized light in the blue wavelength range emitted from the laser light source 1201, and transmitting P-polarized light in the blue wavelength range emitted from the laser light source 1201 and light in the wavelength range of the light converted by the wavelength conversion wheel 1D. Therefore, the P-polarized light in the blue wavelength range emitted from the λ / 4 wave plate 1207 passes through without changing the direction of light propagation and is incident on the subsequent convex lens 1210.

[0166] As the wavelength conversion wheel 1D rotates, wavelength-converted light and blue light are incident on the convex lens 1210 in a time series and are focused near the incident end of the rod integrator 1212, which will be described later. The light focused by the convex lens 1210 is then incident on the color-filtered wheel 1211. The color-filtered wheel 1211 has the same configuration as the color-filtered wheel 1110 used in the light source device 51C employing the wavelength conversion wheel 1C according to Embodiment 6 shown in Figure 15. As the wavelength conversion wheel 1D and the color-filtered wheel 1211 rotate synchronously, light with different wavelength ranges is focused in a time series near the incident end of the rod integrator 1212.

[0167] Light of different wavelengths, incident on the rod integrator 1212, is homogenized by the rod integrator and emitted from the output end. In this embodiment, the wheel with a color filter 1211 is placed near the incident side of the rod integrator, but it may also be placed near the output side.

[0168] The projection-type image display device 101D of Embodiment 7 is, for example, a one-chip type projection-type image display device, as shown in Figure 18. The projection-type image display device 101D includes a light source device 51D. In the projection-type image display device 101D, the behavior of light after emission from the rod integrator 1212 is substantially the same as the behavior of light after emission from the rod integrator 1111, as described for the projection-type image display device 101C shown in Figure 16, so a detailed explanation is omitted here.

[0169] According to the light source device 51D and projection-type image display device 101D of Embodiment 7, by using a wavelength conversion wheel 1D (see Figure 10C) composed of arch-shaped segments or partially arch-shaped segments, production efficiency and yield can be improved.

[0170] (Other embodiments) As described above, the above embodiments have been explained as examples of the technology disclosed in this application. However, the technology relating to this disclosure is not limited to these embodiments and can also be applied to embodiments that have been modified, replaced, added, or omitted. Furthermore, it is possible to create new embodiments by combining the components described in the above embodiments. Embodiments obtained by such modifications and by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure.

[0171] As described above, embodiments have been explained as examples of the technology in this disclosure. For this purpose, attached drawings and a detailed description have been provided. Therefore, among the components described in the attached drawings and detailed description, there may be not only components that are essential for solving the problem, but also components that are not essential for solving the problem, in order to illustrate the above technology. Therefore, the mere fact that these non-essential components are described in the attached drawings and detailed description should not be immediately assumed to mean that these non-essential components are essential. [Industrial applicability]

[0172] This disclosure is applicable to a wavelength conversion element that irradiates illumination light to convert the wavelength of light, a wavelength conversion wheel, a light source device that uses light whose wavelength has been converted by the wavelength conversion wheel, and a projection-type image display device equipped with these light source devices. [Explanation of symbols]

[0173] 1, 1A, 1B, 1C, 1D Wavelength conversion wheel 10A, 10B, 20A segments Aab, Aab1 outer arc edge Bab, Bab1 Inner arc edge 10a, 20a 1st arc section 10c, 10d, 10e edge C10a, C10b, C20a, C30a, C30b yen R10a, R10b radius r10, r20, r30a, r30b radius of curvature θ1, θ2, θ3 central angle 30 Plate-shaped sintered material A1, A2, B1, C1, C2 end points F inflection point 5 Motors 11 circuit boards 11a 1st main surface 11b 2nd principal surface 11c center axis 12 wavelength conversion elements 15a, 15b opening 16a, 16b reflective area 51A, 51B, 51C, 51D light source device 101A, 101B, 101C, 101D Projection-type video display device

Claims

1. A wavelength conversion wheel that converts incident light into light of a different wavelength, A circuit board that can rotate around a rotation axis, One or more wavelength conversion elements are arranged on the substrate and include a wavelength conversion material that is excited by incident light and emits light of a different wavelength from the wavelength of the incident light, Equipped with, The wavelength conversion element is composed of segments, The segment is defined by an inner arc edge, an outer arc edge, and two side edges that connect the endpoints on both sides of the inner arc edge and the outer arc edge, The outer arc edge includes a first arc-shaped portion having the same shape and arc length as the inner arc edge, One or more of the wavelength conversion elements are arranged such that the concave sides of the inner and outer arc edges face inward towards the substrate. Wavelength conversion wheel.

2. The outer arc edge has an inflection point near the end edge of at least one side of the segment, between the endpoint of the outer arc edge on one side and the endpoint of the first arc-shaped portion. The outer arc edge end containing the inflection point includes a shape different from the shape of the inner arc edge. The wavelength conversion wheel according to claim 1.

3. The outer arc edge end is composed of a second arc-shaped portion and a third arc-shaped portion. The second arc-shaped portion and the third arc-shaped portion have opposite curvature directions and are in contact at the inflection point. The wavelength conversion wheel according to claim 2.

4. The first arc-shaped portion and the second arc-shaped portion are located on the circumference of the first circle, The third arc-shaped portion lies on the circumference of the second circle, The first circle and the second circle are circular circles that are circumscribed at the inflection point. The wavelength conversion wheel according to claim 3.

5. The outer arc edge end is composed of a straight section that passes through the inflection point. The wavelength conversion wheel according to claim 2.

6. The first arc-shaped portion and one of the endpoints of the straight portion lie on the circumference of the first circle. The other endpoint of the aforementioned straight section lies on the circumference of the second circle. The first circle and the second circle are circular circles that are circumscribed at the inflection point. The wavelength conversion wheel according to claim 5.

7. The endpoints on the same side of the first arc-shaped portion and the inner arc edge lie on a straight line perpendicular to the straight line connecting the two endpoints of the inner arc edge. The wavelength conversion wheel according to claim 1 or 2.

8. The endpoints on the same side of the first arc-shaped portion and the inner arc edge are located on the edge on one side. The wavelength conversion wheel according to claim 1.

9. The inflection point is located only near the aforementioned edge on one side, The endpoint on the same side of the first arc-shaped portion and the inner arc edge lies on the other end edge, The wavelength conversion wheel according to claim 2.

10. The wavelength conversion element is arranged in a ring shape including a partially missing portion around the rotation axis. The substrate has an opening at a position corresponding to the missing portion of the wavelength conversion element. The wavelength conversion wheel according to claim 1 or 2.

11. The wavelength conversion element is arranged in a ring shape including a partially missing portion around the rotation axis. The substrate has a reflection region at a position corresponding to the missing portion of the wavelength conversion element. The wavelength conversion wheel according to claim 1 or 2.

12. The wavelength conversion elements are arranged in a ring shape around the rotation axis, The aforementioned ring-shaped portion is a reflection region. The wavelength conversion wheel according to claim 1 or 2.

13. The first arc-shaped portion of one or more of the wavelength conversion elements is configured to be arranged along the circumference of a circle centered on the rotation axis. The wavelength conversion wheel according to claim 1 or 2.

14. The device comprises two or more wavelength conversion elements, each containing a wavelength conversion material that emits light of different wavelengths. The wavelength conversion wheel according to claim 1 or 2.

15. A light source that emits the incident light, The wavelength conversion wheel according to claim 1 or 2, comprising: Light source device.

16. The light source device according to claim 15, A light modulation element that spatially modulates incident light according to a video signal, An illumination optical system that guides the illumination light emitted from the light source device to the light modulation element, A projection optical system that magnifies and projects the light emitted from the aforementioned optical modulation element to display an image, Equipped with, Projection-type image display device.

Images