Light source device and projection-type video display device

Abstract

This light source device comprises: a plurality of light source units; a phosphor wheel having an annular phosphor layer for wavelength-converting light from the plurality of light source units into light in a different wavelength region; and an excitation light guide system for guiding the light from the plurality of light source units as an excitation light spot onto the phosphor layer. The excitation light spot has an anisotropic shape with respect to the geometric center of the excitation light spot, the anisotropic shape having, on a first axis and a second axis that are orthogonal to each other and that pass through the geometric center, a length in the direction of the first axis that is greater than the length in the direction of the second axis. The excitation light guide system guides the excitation light spot onto the phosphor layer such that the first axis is inclined with respect to a straight line connecting the rotation center of the phosphor wheel and the geometric center of the excitation light spot.

Description

Light source device and projection-type image display device

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

[0002] A projection-type image display device is known that includes a phosphor wheel having a phosphor layer that converts the wavelength of laser light output from a light source into a different wavelength range. When the phosphor layer is heated by the laser light, the luminous efficiency of the phosphor layer decreases as the temperature rises. Patent Document 1 discloses a display device that includes a rotating disk having a phosphor layer and a light source that irradiates the phosphor layer with laser light, and that displays using the laser light and fluorescence wavelength-converted by the phosphor, where the rotation direction of the rotating disk is configured to be approximately perpendicular to the longitudinal direction of the laser light spot. Patent Document 1 also discloses that when the laser light is an elliptical spot, the widest effective irradiation area can be obtained, thereby suppressing temperature rise of the phosphor.

[0003] Japanese Patent Application Laid-Open No. 2023-156615

[0004] However, Patent Document 1 only takes into consideration the magnitude of the spot projection amount in the direction of the rotation radius of the phosphor layer, and in reality, the shape and light amount distribution of the irradiated laser light spot differ in the direction of the rotation radius, so the temperature rise of the phosphor layer is not uniform in the direction of the rotation radius. Therefore, the concept of this document may not be applicable to actual cases.

[0005] Therefore, an object of the present disclosure is to provide a technology that takes into consideration the shape of the laser light spot and the distribution of the light intensity in the direction of the radius of rotation, and suppresses the temperature rise of the phosphor layer that is affected by these factors.

[0006] A light source device according to one aspect of the present disclosure includes a plurality of light source units, a phosphor wheel having an annular phosphor layer that wavelength-converts light from the plurality of light source units into light of different wavelength ranges, and an excitation light guide system that guides the light from the plurality of light source units as an excitation light spot on the phosphor layer. The excitation light spot has an anisotropic shape with respect to its geometric center, with a length in the direction of the first axis being longer than a length in the direction of the second axis, the first axis being orthogonal to a first axis and a second axis that pass through the geometric center of the excitation light spot. The excitation light guide system guides the excitation light spot onto the phosphor layer so that the first axis is inclined with respect to a line connecting the center of rotation of the phosphor wheel and the geometric center of the excitation light spot.

[0007] One aspect of the present disclosure provides a projection-type image display device including the above light source device.

[0008] According to the present disclosure, it is possible to derive a spot arrangement that suppresses a temperature rise in the phosphor layer by taking into consideration the influence of the spot shape and light amount distribution.

[0009] FIG. 1 shows a first example of the positional relationship between the excitation light guide system and the phosphor wheel. FIG. 2 shows a first example of the positional relationship between the excitation light spot and the phosphor wheel. FIG. 3 shows a second example of the positional relationship between the excitation light guide system and the phosphor wheel. FIG. 4 shows a third example of the positional relationship between the excitation light guide system and the phosphor wheel. FIG. 5 shows a third example of the positional relationship between the excitation light spot and the phosphor wheel. FIG. 6 shows a shape at the spot position in the first example of the positional relationship between the excitation light guide system and the phosphor wheel. FIG. 7 shows the distance from the center of rotation at the spot position in the first example of the positional relationship between the excitation light guide system and the phosphor wheel, and the integrated amount of excitation light in one rotation. FIG. 8 shows the positional relationship between the excitation light guide system and the phosphor wheel in an embodiment. (a) A diagram showing the light intensity distribution in the y'-axis direction of the excitation light spot in an embodiment, (b) A diagram showing the light intensity distribution in the x'-axis direction of the excitation light spot in an embodiment. FIG. 9 shows the shape of the first light intensity portion of the excitation light spot. FIG. 1 shows the maximum integrated amount of light. FIG. 2 shows the shape of the second light amount portion of the excitation light spot. FIG. 3 shows the maximum integrated amount of excitation light when one of the second light amount portions of the excitation light spot makes one rotation when the angle between the rotation center of the phosphor and the center of the excitation light spot is changed. FIG. 4 shows the positional relationship between the second light amount portions of the excitation light spot. FIG. 5 shows the maximum integrated amount of excitation light when the excitation light spot of Example 1 makes one rotation when the angle between the rotation center of the phosphor and the center of the excitation light spot is changed. FIG. 6 shows the light source device of the first embodiment. FIG. 7 shows the light source device of the second embodiment. FIG. 8 shows the light source device of the third embodiment. FIG. 9 shows the phosphor wheel used in the light source device of the third embodiment. FIG. 10 shows the light source device of the fourth embodiment. FIG. 11 shows the phosphor wheel used in the light source device of the fourth embodiment. FIG. 12 shows the projection type image display device using the light source device of the first embodiment. FIG. 13 shows the projection type image display device using the light source device of the second embodiment. FIG. 14 shows the projection type image display device using the light source device of the third embodiment.

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with appropriate reference to the drawings. However, more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure and are not intended to limit the subject matter described in the claims. Furthermore, the function of one configuration shown in the present embodiment may be realized by two or more physical configurations, or the functions of two or more configurations may be realized by, for example, one physical configuration.

[0011] A light source device for a projection type image display device provides an emitted light beam having a shape that takes into consideration the aspect ratio (width-to-height ratio) of a display element used in the projection type image display device.

[0012] In a light source device having a light source and a phosphor layer that converts the wavelength of light emitted from the light source as excitation light and emits fluorescence, the shape of the emitted light flux from the light source device is determined by the shape of the excitation light spot on the phosphor layer, which is formed by an excitation light guide system that guides the light emitted from the light source to the phosphor layer. For this reason, the shape of the excitation light spot is often determined taking into account the aspect ratio of the display element, and is usually approximately rectangular. Note that the approximately rectangular shape here refers to a shape defined by the long axis direction of the spot and the short axis direction perpendicular to the long axis direction.

[0013] Furthermore, even if the shape of the excitation light spot is the same, the effect of the excitation light on the phosphor layer of the phosphor wheel varies depending on the positional relationship between the excitation light guide system and the phosphor wheel.

[0014] 1A is a diagram showing a first example of the positional relationship between the excitation light guide system and the phosphor wheel. The positional relationship between the phosphor wheel and the excitation light guide system and the shape of the excitation light spot will be described using FIG. 1A. In FIG. 1A, the rotating substrate of the phosphor wheel 20 is the xy plane, and the normal direction to this plane is the z axis.

[0015] The excitation light guide system 10 includes a light source unit 11 , a convex lens 12 , a concave lens 13 , a diffusion plate 14 , a dichroic mirror 15 , a convex lens 16 , and a convex lens 17 .

[0016] The light source unit 11 includes a heat sink 111 to which a plurality of laser light sources 112 are attached, and collimator lenses 113 that are provided corresponding to each of the laser light sources 112 and collimate the light from the laser light sources 112. Although two light source units are shown in Fig. 1A, the number of light source units is not limited to two and may be one or three or more.

[0017] Laser light emitted from light source unit 11 enters convex lens 12, and the emitted light converges and enters concave lens 13. The laser light that enters concave lens 13 is collimated and enters diffuser plate 14. The diffuser plate 14 diffuses the incident laser light to make it uniform, and the laser light then enters dichroic mirror 15, which is positioned so that it forms a 45-degree angle with the z-axis.

[0018] Dichroic mirror 15 has optical properties that allow light in the wavelength range of the laser light emitted from laser light source 112 to pass through and reflect light in the wavelength range of the fluorescence obtained by wavelength conversion of the laser light in phosphor wheel 20, which will be described later. The laser light that has entered dichroic mirror 15 passes through dichroic mirror 15 having the optical properties described above and enters convex lens 16. The laser light that has entered convex lens 16 is converged by an optical system that is combined with convex lens 17 in the subsequent stage, and is collected as excitation light spot 18a on phosphor layer 22 of phosphor wheel 20, which will be described later.

[0019] The diffusion plate 14 may have different diffusion amounts in the x-axis and y-axis directions, or may have the same diffusion amount.

[0020] FIG. 1B shows a first example of the positional relationship between the excitation light spot and the phosphor wheel. The phosphor wheel 20 will be described using FIG. 1B . As shown in the coordinate system shown in the upper right of FIG. 1B , a rotatable substrate 21 is disposed on an xy plane with the center of rotation O of the phosphor wheel 20 as the origin. A motor 23 is provided to rotate around the center of rotation O of the rotatable substrate 21, and the phosphor layer 22 is provided on the rotatable substrate 21 in the shape of a ring at the same distance from the center of rotation O. The ring-shaped phosphor layer is rotated by the motor. The excitation light spot 18a is focused on the phosphor layer 22 at an angle θ with respect to the x-axis shown in the figure, forming a rectangle with the x-axis as its major axis and the y-axis as its minor axis.

[0021] In FIG. 1B, the geometric center of the excitation light spot 18a is Q, the line connecting the rotation center of the phosphor wheel is the x'-axis, and the axis passing through the rotation center O and perpendicular to the x'-axis is the y'-axis.

[0022] The fluorescence excited by the laser light focused as excitation light spot 18a on phosphor wheel 20 and subjected to wavelength conversion changes its direction of travel and enters dichroic mirror 15. As described above, dichroic mirror 15 has the property of reflecting wavelength-converted fluorescence, and by reflecting the light, changes the direction of travel of the light by 90 degrees and causes it to enter convex lens 31. The fluorescence that enters convex lens 31 and is focused enters rod integrator 32, whose entrance surface is located near the focusing position, where it is homogenized and emitted.

[0023] Fig. 2A is a diagram showing a second example of the positional relationship between the excitation light guide system and the phosphor wheel. Fig. 2B is a diagram showing a second example of the positional relationship between the excitation light spot and the phosphor wheel. Fig. 3A is a diagram showing a third example of the positional relationship between the excitation light guide system and the phosphor wheel. Fig. 3B is a diagram showing a third example of the positional relationship between the excitation light spot and the phosphor wheel.

[0024] 2A and 2B show the case where θ is 0° in FIGS. 1A and 1B, and FIGS. 3A and 3B show the case where θ is 90° in FIGS. 1A and 1B. The only difference is the relative positions of the excitation light guide system 10 and the phosphor wheel; the behavior of the light remains the same, so detailed explanations will be omitted here.

[0025] Also, in FIGS. 2B and 3B, the x' and y' axes can be set in the same way as in FIG. 1B.

[0026] Furthermore, the positional relationship between the excitation light spot 18 and the phosphor wheel 20 can be represented by moving θ in Figures 1A and 1B in the range from 0° to 90° by taking into account the symmetry of the x-axis, y-axis, and rotation center O, and the following explanation will be given assuming that θ is in the range of 0° or more and 90° or less.

[0027] 4A is a diagram showing the shape of the excitation light spot at the position in a first example of the positional relationship between the excitation light guide system and the phosphor wheel. Fig. 4A shows the excitation light spot 18a shown in Figs. 1A and 1B on the x' and y' axes. The points of the approximately rectangular excitation light spot 18a are designated as ABCD. When the approximately rectangular excitation light spot ABCD and the geometric center Q of the excitation light spot are arranged in ascending order of distance from the center of rotation O, the order is DAQCB, and the distances from the center of rotation O to each point are designated as r1, r2, r0, r3, and r4.

[0028] 4B is a diagram showing the distance from the center of rotation to the excitation light spot position and the integrated amount of excitation light per one rotation in a first example of the positional relationship between the excitation light guide system and the phosphor wheel. Fig. 4B also shows the integrated amount of excitation light when the excitation light spot 18a shown in Fig. 4A rotates once around O. The integrated amount of excitation light can be determined by the angle of the arc where the excitation light spot 18a overlaps with a circle of radius r from the center of rotation O. In other words, circles with a radius of r1 or less or circles with a radius of r4 or more do not overlap with the excitation light spot 18a, so the angle of the arc is 0° and the integrated amount of excitation light is 0.

[0029] The arcs where the circles of radii r2, r0, and r3 overlap with the excitation light spot 18a are AA', Q'Q", and C'C, respectively, and have approximately the same value (length), but the angle becomes larger as the radius becomes smaller. Figure 4B is a graph showing this with the horizontal axis representing the distance from the center of rotation and the vertical axis representing the integrated amount of excitation light per one rotation, and in this case, the integrated amount of excitation light reaches its maximum when the distance from the center of rotation is r2, as represented by point P on Figure 4B.

[0030] On the other hand, ideally, it is desirable that the light intensity distribution within the excitation light spot 18 be uniform, but in reality, it often becomes non-uniform. The following description will be made with reference to Figures 5A and 5B. Figure 5A is a diagram showing the positional relationship between the excitation light guide system and the phosphor wheel in this embodiment. Figure 5B(a) is a diagram showing the light intensity distribution of the excitation light spot in the y'-axis direction in this embodiment, and Figure 5B(b) is a diagram showing the light intensity distribution of the excitation light spot in the x'-axis direction in this embodiment.

[0031] Specifically, to make the excitation light spot approximately rectangular to match the shape of the display element of the projection-type video display device, multiple light source units 11 are often positioned farther away from the optical axis of the excitation light guide system in the long axis direction (x axis direction in the figure) than in the short axis direction (y axis direction in the figure) of the excitation light spot. In this case, light from light source units 11 that are farther away from the optical axis cannot be fully focused, resulting in uniformity in the y" axis direction but non-uniformity in the x" axis direction, as shown in Figures 5B(a) and 5B(b). Here, the y" axis is an axis that passes through the geometric center Q of the excitation light spot and is parallel to the y axis, and the x" axis is an axis that passes through the geometric center Q of the excitation light spot and is parallel to the x axis. The non-uniformity in the x" direction is symmetrical with respect to the y" axis, resulting in a configuration with a concave center and convex portions on both sides. Here, the portion up to the central concave portion is referred to as a first light intensity region 18d, and the convex portions on both sides are referred to as a second light intensity region 18e. Here, for convenience, the height h in the y"-axis direction is 1 / e when the maximum value of the light intensity distribution in the y"-axis direction is 1. ２ This is represented by the distance to the area.

[0032] Similarly, the width w of the x″ axis direction is 1 / e ２ This width w is represented as the width of the first light intensity region.

[0033] Next, if the minimum value of the concave portion at the center of the light intensity distribution in the x″-axis direction is A, then 1 / e ２ (specifically, (1-A) / e ２ The width w2 of the second light intensity distribution is represented as the width of the second light intensity region. The distance between the centers of the two second light intensity distributions is represented as c.

[0034] The following description will be made using the above-defined values ​​of h, w1, w2, and c.

[0035] Fig. 6A is a diagram showing the shape of the first light intensity portion of the excitation light spot. Fig. 6B is a diagram showing the maximum integrated amount of excitation light when the first light intensity portion of the excitation light spot rotates once when the angle between the rotation center of the phosphor wheel and the center of the excitation light spot is changed. First, using Fig. 6A and Fig. 6B, the relationship between the shape of the first light intensity region 18d, the angle θ between the x-axis and the line connecting the rotation center of the phosphor wheel and the center of the excitation light spot, and the maximum integrated amount of excitation light intensity will be described.

[0036] First, as shown in FIG. 6A, the diagonal of the substantially rectangular first light intensity region 18d is defined as Φ, and Φ can be expressed by the following formula: tan Φ=h / w1

[0037] Using the above-defined Φ, the relationship between the angle θ between the x-axis and the line connecting the center of rotation of the phosphor wheel and the center of the excitation light spot and the maximum value of the integrated amount of excitation light intensity is shown as a graph in Figure 6B, where the maximum value is reached when the angle θ is Φ.

[0038] 7A is a diagram showing the shape of the second light intensity portion of the excitation light spot. Fig. 7B is a diagram showing the maximum integrated amount of excitation light when one of the second light intensity portions of the excitation light spot rotates once when the angle between the rotation center of the phosphor wheel and the center of the excitation light spot is changed. Next, using Fig. 7A and Fig. 7B, we will explain the relationship between the angle θ between the x-axis and the line connecting the rotation center of the phosphor wheel and the center of the excitation light spot when only one second light intensity region 18e is present, and the maximum integrated amount of excitation light intensity.

[0039] First, as shown in FIG. 7A, when the diagonal of the substantially rectangular second light intensity region 18e is ω, Φ can be expressed by the following formula: tan ω=h / w2

[0040] Using the above-defined ω, the relationship between the angle θ between the x-axis and the line connecting the center of rotation of the phosphor wheel and the center of the excitation light spot and the maximum value of the integrated amount of excitation light intensity is shown as a graph in Figure 7B, where the maximum value is reached when the angle θ is ω.

[0041] 8 is a diagram showing the positional relationship between the second light intensity portions of the excitation light spot. In reality, there are two second light intensity regions, so the angles α and β shown in FIG. 8 must also be taken into consideration. α and β are expressed by the following equations: tan α=h / (c-w2) tan β=h / (c+w2)

[0042] FIG. 9 is a diagram showing the maximum integrated amount of excitation light when the excitation light spot of Example 1 makes one rotation when the angle formed between the center of rotation of the phosphor and the center of the excitation light spot is changed.

[0043] 6 to 8, the relationship between the angle θ between the x-axis and the line connecting the center of rotation of the phosphor wheel and the center of the excitation light spot and the maximum value of the integrated amount of excitation light intensity for the excitation light spot 18 having the non-uniform light intensity distribution shown in Figures 5B(a) and 5B(b) is as shown in Figure 9, which has a minimum portion surrounded by dotted line E1 in the figure. Furthermore, by arranging the excitation light guide system and phosphor wheel so as to realize the angle of this minimum portion, the thermal load on the phosphor layer from the excitation light spot can be minimized, and burnout can be avoided, thereby improving reliability.

[0044] The conditions for minimizing the above-mentioned heat load are summarized below, focusing on the positional relationship between the excitation light guide system and the phosphor wheel and the relationship between the excitation light spot and the phosphor wheel. (1) The long axis of the excitation light spot is not parallel to the line connecting the geometric center of the excitation light spot and the center of rotation of the phosphor wheel. (2) The long axis of the first light intensity region is approximately perpendicular to the long axis of the second light intensity region. (3) The angle between the long axis of the excitation light spot and the line connecting the geometric center of the excitation light spot and the center of rotation of the phosphor wheel is smaller than the angle (Φ) between the long axis of the second light intensity region and the diagonal. (4) The angle between the long axis of the excitation light spot and the line connecting the geometric center of the excitation light spot and the center of rotation of the phosphor wheel is larger than the angle (ω) between the short axis of the first light intensity region and the diagonal. (5) The angle formed by the line connecting the geometric center of the excitation light spot and the center of rotation of the phosphor wheel and the long axis of the excitation light spot is smaller than the angle (β) formed by the line connecting the center of the excitation light spot and the outer vertex of the short axis of the second light intensity region and the short axis of the excitation light spot.

[0045] Hereinafter, a light source device and a projection-type image display device that actually include an excitation optical system and a phosphor wheel in the positional relationship that satisfies the above conditions will be specifically described.

[0046] (Light source device of first embodiment utilizing the positional relationship between the excitation light guide system and the phosphor wheel) Fig. 10 is a diagram showing a light source device of the first embodiment. A light source device 1100 of the first embodiment utilizing the positional relationship between the excitation light guide system and the phosphor wheel of the present disclosure will be described in detail below with reference to Fig. 10 .

[0047] This device uses the phosphor wheel shown in Fig. 1B. Details of the phosphor wheel shown in Fig. 1B have been described above, so a detailed description will not be given here. Similarly, details of the excitation light guide system 10 and illumination optical system 30 shown in Fig. 1A have also been described above, so a detailed description will not be given here.

[0048] The light source device 1100 is provided with a new blue optical system 40 in addition to the excitation light guide system 10, phosphor wheel 20, and illumination optical system 30 described above.

[0049] The blue optical system 40 is composed of a light source unit 41, a convex lens 42, a concave lens 43, and a diffuser plate 44, and is arranged so that its optical axis is perpendicular to that of the excitation light guide system 10, and the dichroic mirror 15 forms an angle of 45° with respect to each optical axis.

[0050] The light source unit 41 includes a heat sink 411 to which a plurality of laser light sources 412 are attached, and collimator lenses 413 that collimate light from the laser light sources 112 provided corresponding to each of the laser light sources 412. Although two light source units are shown in Fig. 1A, the number of light source units is not limited to two and may be one or three or more.

[0051] The laser light emitted from the light source unit 41 enters the convex lens 42, and the emitted light is converged and enters the concave lens 43. The laser light that enters the concave lens 43 is collimated and enters the diffusion plate 14. The diffusion plate 44 diffuses the incident laser light to make it uniform, and then the laser light enters the dichroic mirror 15.

[0052] The dichroic mirror 15 has the property of transmitting light in the wavelength range of the laser light emitted from the laser light source 412. The laser light incident on the dichroic mirror 15 passes through the dichroic mirror 15 having the optical properties described above, and enters the illumination optical system 30.

[0053] Separately, the excitation light from the excitation light guide system 10 is wavelength-converted by the phosphor wheel 20 to produce fluorescence, and the laser light emitted from the blue optical system 40 are combined to become white light, which passes through the convex lens 31 and the rod integrator 32 and is emitted.

[0054] (Light source device of second embodiment utilizing the positional relationship between the excitation light guide system and the phosphor wheel) Fig. 11 is a diagram showing a light source device of the second embodiment. A light source device 1200 of the second embodiment utilizing the positional relationship between the excitation light guide system and the phosphor wheel of the present disclosure will be described in detail below with reference to Fig. 11 .

[0055] This device uses a phosphor wheel shown in Fig. 1B. Details of the phosphor wheel shown in Fig. 1B have been described above, so a detailed description will be omitted here. In addition, the configuration up to the diffuser plate 14 of the excitation light guide system 10 shown in Fig. 1A is the same, so that description will be omitted, and the portion after the diffuser plate 14 will be described using Fig. 11.

[0056] The laser light that has passed through the diffuser plate 14 is incident on the subsequent retardation plate 51. The retardation plate 51 is arranged so that its optical axis is in the normal direction and is rotatable about the optical axis, and this rotation adjusts the ratio of P-polarized light to S-polarized light in the outgoing laser light to a predetermined ratio.

[0057] The laser light, the ratio of P-polarized light to S-polarized light of which has been adjusted by the phase difference plate 51, is incident on a dichroic mirror 54 with a polarization separation function.

[0058] The dichroic mirror 54 with polarization separation function has the property of transmitting P-polarized light in the blue wavelength range of laser light, and reflecting fluorescence wavelength-converted when light in the blue wavelength range of laser light is irradiated onto the phosphor wheel 20, and S-polarized light in the blue wavelength range of laser light.

[0059] The P-polarized component of the laser light, the ratio of P-polarized light to S-polarized light of which has been adjusted by the phase difference plate 51, passes through the polarization separation dichroic mirror 54, which has the characteristics described above. The behavior of light at the subsequent convex lenses 16 and 17 and the phosphor wheel 20 has already been explained, so details will be omitted, but the fluorescence from the phosphor wheel 20 is incident on the polarization separation dichroic mirror 54 from the opposite direction to the excitation light guide system 10.

[0060] The S-polarized component of the laser light, the ratio of P-polarized light to S-polarized light adjusted by the retardation plate 51, is reflected by a dichroic mirror 54 with polarization separation function and the characteristics described above. The S-polarized component of the laser light, whose direction of propagation has been changed by 90° upon reflection, enters the downstream λ / 4 plate 52. The λ / 4 plate 52 has a slow axis oriented at 45° around the optical axis relative to the direction of vibration of the polarization of the laser light, and rotates the polarization direction of the S-polarized component of the laser light from the linear direction to become circularly polarized light. The laser light that entered the λ / 4 plate 52 then enters the downstream total reflection mirror 53. The total reflection mirror is positioned so that the incident optical axis is normal to the mirror. The incident circularly polarized laser light changes its direction of propagation by 180° while maintaining its polarization direction, and then enters the λ / 4 plate 52 again. Because the λ / 4 plate 52 has the slow axis described above, the incident circularly polarized laser light is rotated, and its polarization direction becomes P-polarized.

[0061] The P-polarized laser light that has passed through the λ / 4 plate 52 twice and is emitted is incident on a dichroic mirror 54 with a polarization separation function from a direction that is 90° different from the direction of the fluorescent light.

[0062] Since the dichroic mirror 54 with polarization separation function has the above-mentioned characteristics, it transmits the laser light from the total reflection mirror 53 and reflects and combines the fluorescent light from the phosphor wheel 20 to become white light. The white light enters the concave lens 55 to widen the beam width, and then enters the convex lens 56 to be collimated.

[0063] The white light collimated by the convex lens 56 is incident on one of a pair of fly-eye lenses 57, which are made up of an array of multiple convex lenses. The light that has exited one of the fly-eye lenses 57 has its direction of travel changed by 90° by a total reflection mirror 58 and is incident on the other fly-eye lens 57. The pair of fly-eye lenses 57 homogenize the light beam.

[0064] The light emitted from the pair of fly-eye lenses 57 is unified in polarization by a polarization conversion array 59 in which polarizing beam splitters (PBS) are arranged in an array, and then emitted.

[0065] (Light source device of third embodiment utilizing the positional relationship between the excitation light guide system and the phosphor wheel) Fig. 12 is a diagram showing a light source device of a third embodiment. A light source device 1300 of a third example utilizing the positional relationship between the excitation light guide system and the phosphor wheel of the present disclosure will be described in detail below with reference to Fig. 12 .

[0066] In this device, the configuration up to the diffusion plate 14 of the excitation light guide system 10 shown in FIG. 1A is the same as that shown in FIG. 1A, so that description will be omitted and the portion after the diffusion plate 14 will be described with reference to FIG.

[0067] The laser light from the excitation light guide system 10 is incident on a dichroic mirror 69 .

[0068] The dichroic mirror 69 has the property of reflecting light in the blue wavelength range of the laser light from the excitation light guide system 10 and transmitting light in the fluorescent wavelength range to which the laser light from the excitation light guide system 10 is wavelength converted by the phosphor wheel 210 described below.

[0069] The laser light from the excitation light guide system 10 that has entered the dichroic mirror 69 changes its traveling direction by 90°, and is then focused by the convex lenses 16 and 17 at approximately the position of the rotating substrate of the phosphor wheel 210 .

[0070] 13 is a diagram showing a phosphor wheel used in the light source device of the third embodiment. Details of the phosphor wheel 210 will be described below with reference to FIG.

[0071] The phosphor wheel 210 has phosphor layers 212 and 214, which emit fluorescent light of different wavelengths that are wavelength-converted by the laser light from the excitation light guide system described above, provided on a rotating substrate 211 provided with a motor 213, in a portion of the annular shape at the same distance from the center of rotation. An opening 215 is provided in a portion of the annular shape on the rotating substrate 211 other than the phosphor layers 212 and 214, which emit fluorescent light of different wavelengths that are wavelength-converted by the laser light from the excitation light guide system described above, in a portion of the annular shape at the same distance from the center of rotation.

[0072] The following description will be given of the case where light is focused on the opening 215 on the phosphor wheel 210 and the phosphor layers 212 and 214 .

[0073] The light from excitation light guide system 10, which is condensed at opening 215 on phosphor wheel 210, passes through opening 215 and is collimated by subsequent convex lenses 61 and 62. The laser light, which has been collimated by subsequent convex lenses 61 and 62, has its traveling direction changed by a relay system made up of total reflection mirrors 63, 65, and 67 and convex lenses 64, 66, and 68, and is incident on dichroic mirror 69 described above from a direction 180° opposite to that of excitation light guide system 10.

[0074] The dichroic mirror 69 has the above-mentioned property of reflecting the laser light, so that the laser light changes its traveling direction by 90° and enters the convex lens 31 at the subsequent stage.

[0075] The fluorescence, which is wavelength-converted light from the excitation light guide system 10 that is focused on the phosphor layers 212, 214 on the phosphor wheel 210, changes its direction of travel by 180° and enters the convex lenses 17, 16 again, where it is collimated and enters the dichroic mirror 69.

[0076] The dichroic mirror 69 has the property of transmitting the aforementioned fluorescent light, so the fluorescent light maintains its direction of travel and enters the subsequent convex lens 31 .

[0077] As the phosphor wheel rotates, the laser light and fluorescent light combined by the dichroic mirror 69 are switched in a time-division manner. The light of different wavelengths collected by the convex lens 31 in a time series is incident on the color wheel 33 located approximately at the collecting point.

[0078] The color wheel 33 is composed of a combination of dichroic mirrors that have different characteristics in the wavelength range of light that they transmit or reflect, and the combination of the phosphor wheel 210 and the color wheel 33 causes light that constitutes the desired white light in a time series to exit the color wheel 33.

[0079] The light emitted from color wheel 33 is homogenized by passing through the subsequent rod integrator 32 before being emitted. In the above description, color wheel 33 is disposed on the incident side of rod integrator 32, but it may also be disposed on the exit side of rod integrator 32.

[0080] (Light source device of fourth embodiment utilizing the positional relationship between the excitation light guide system and the phosphor wheel) Fig. 14 is a diagram showing a light source device of a fourth embodiment. A light source device 1400 of a fourth example utilizing the positional relationship between the excitation light guide system and the phosphor wheel of the present disclosure will be described in detail below with reference to Fig. 14 .

[0081] In this device, the configuration up to the diffuser plate 14 of the excitation light guide system 10 shown in FIG. 1A is the same as the light in the illumination optical system 30 after the convex lens 31, so we will omit that description and instead explain the behavior of light between the diffuser plate 14 and the convex lens 31 using FIG. 14.

[0082] The laser light from the excitation light guide system 10 that has exited the diffusion plate 14 passes through a phase difference plate 71, where the polarization direction of the light is unified to S-polarized light, and then enters a dichroic mirror 72 with a polarization separation function.

[0083] The dichroic mirror 72 with polarization separation function has the property of reflecting S-polarized light in the blue wavelength range of the laser light from the excitation light guide system 10, and transmitting light in the fluorescent wavelength range to which the laser light from the excitation light guide system 10 is wavelength converted by the phosphor wheel 220 described below, and P-polarized light in the blue wavelength range of the laser light from the excitation light guide system 10.

[0084] The laser light emitted from the phase difference plate 71 has its polarization direction adjusted to S-polarized light, and is reflected by the dichroic mirror 72 with polarization separation function, changing the traveling direction of the light by 90°. The S-polarized component of the laser light whose traveling direction has been changed by 90° is incident on the subsequent λ / 4 plate 52. The λ / 4 plate 73 has a slow axis in a direction at an angle of 45° around the optical axis with respect to the vibration direction of the polarization of the laser light, and the S-polarized component of the laser light is rotated from its linear polarization direction to become circularly polarized light, and is then focused by the convex lenses 16 and 17 approximately onto the substrate on the phosphor wheel 220.

[0085] 15 is a diagram showing a phosphor wheel used in the light source device of the fourth embodiment. Details of the phosphor wheel 220 will be described below with reference to FIG.

[0086] Phosphor wheel 220 has phosphor layers 222 and 224, which emit fluorescent light of different wavelengths that are wavelength-converted by laser light from the excitation light guide system, provided on a rotating substrate 221 provided with a motor 223, in a portion of the annular shape at the same distance from the center of rotation. Phosphor wheel 20 also has a reflective layer 225 provided on a portion of the annular shape at the same distance from the center of rotation, other than phosphor layers 222 and 224, on rotating substrate 221.

[0087] The following description will be given of the case where light is focused on the reflective layer 225 and the phosphor layers 222 and 224 on the phosphor wheel 220 .

[0088] The circularly polarized light of the laser light from the excitation light guide system 10 that is focused on the reflective layer 225 on the phosphor wheel 220 is reflected by the reflective layer 225, changing the traveling direction of the light by 180°, and is then collimated by the subsequent convex lenses 16 and 17. The circularly polarized light of the laser light that has been collimated by the convex lenses 16 and 17 is again incident on the λ / 4 plate 73, where its polarization direction is rotated to become P-polarized light.

[0089] The P-polarized laser light emitted from the λ / 4 plate 73 is incident on the dichroic mirror with polarization separation function 72. Since the dichroic mirror with polarization separation function 72 has the property of transmitting P-polarized light in the blue wavelength range of laser light, the laser light passes through as is and enters the convex lens 31.

[0090] The fluorescence obtained by wavelength conversion of light from excitation light guide system 10 that has been focused on phosphor layers 222, 224 on phosphor wheel 220 changes its traveling direction by 180° and enters convex lenses 17, 16 again, where it is collimated and enters dichroic mirror 72 with polarization separation function. Dichroic mirror 72 with polarization separation function has the property of transmitting fluorescence, so the fluorescence passes through as is and enters convex lens 31.

[0091] In addition, since the dichroic mirror 72 with polarization separation function has the ability to transmit P-polarized and S-polarized fluorescent light, the behavior of the light is not affected even when the light passes through the λ / 4 plate 73 (phase difference plate).

[0092] The behavior of light after the convex lens 31 is the same as that of the light source device 1300, and therefore, as described above, further description will be omitted.

[0093] (Projection-type image display device employing the light source device of the first embodiment utilizing the positional relationship between the excitation light guide system and the phosphor wheel) Fig. 16 is a diagram showing a projection-type image display device employing the light source device of the first embodiment. Next, Fig. 16 shows a projection-type image display device 1600 employing the light source device 1100 of the first embodiment utilizing the positional relationship between the excitation light guide system and the phosphor wheel of the present disclosure. Note that the behavior of light up to the rod integrator 32 has already been explained for the light source device 1100, so a detailed explanation will be omitted.

[0094] The light emitted from the rod integrator 32 then enters a relay lens system made up of three convex lenses 801 , 802 , and 803 .

[0095] Light that exits the relay lens system made up of convex lenses 801, 802, and 803 enters total reflection prism 811. Total reflection prism 811 is made up of two prisms and a tiny gap, and the tiny gap serves as total reflection surface 812 that reflects light that is incident at a specific angle or greater. Light that enters total reflection prism 811 from the relay lens system made up of convex lenses 801, 802, and 803 at an angle greater than the total reflection angle is totally reflected and enters color prism 821.

[0096] The color prism 821 is composed of three glass blocks arranged with a small gap between the first and second prisms, and a small gap between the second and third glass blocks. The first glass block between the first and second blocks has a blue-reflecting dichroic mirror layer, and the second and third glass blocks have a red-reflecting dichroic mirror layer.

[0097] Light of all wavelength ranges that enters color prism 821 passes through the first glass block. Of the light of all wavelength ranges that enters the first glass block, blue light is reflected by a blue-reflecting dichroic mirror layer formed between the second glass block, changes its direction of travel, and enters and is reflected at an angle greater than the total reflection angle into a minute gap provided between total reflection prism 811 and color prism 8211, and is then guided to DMD 831.

[0098] Of the light of all wavelengths incident on the first glass block, red light passes through the blue-reflecting dichroic mirror layer formed between the first and second glass blocks, passes through the minute gap between the first and second glass blocks, and enters the second glass block. The red light incident on the second glass block is reflected by the red-reflecting dichroic mirror layer formed between the second glass block and the third glass block, and is reflected at an angle greater than the total reflection angle into the minute gap between the first and second glass blocks, and is then guided to the DMD 832.

[0099] Of the light of all wavelengths incident on the first glass block, green light passes through a blue-reflecting dichroic mirror layer formed between the first and second glass blocks, passes through the minute gap between the first and second glass blocks, and enters the second glass block. The green light incident on the second glass block passes through a red-reflecting dichroic mirror layer formed between the second glass block and the third glass block, passes through the third glass block, and is guided to the DMD 833.

[0100] The DMDs 831, 832, and 833 are each made up of a plurality of micromirrors that correspond to pixels, and change the direction of light travel by changing the tilt direction of the micromirrors in response to a video signal in a video circuit (not shown).

[0101] The green light, whose direction of travel is changed by DMD 833 in accordance with the video signal, reaches the third glass block, passes through the red-reflecting dichroic mirror layer provided between the third and second glass blocks, the second glass block, the minute gap provided between the second and first glass blocks, the blue-reflecting dichroic mirror layer, and the first glass block, and is then incident on the total reflection prism 811.

[0102] Next, the red light, which has changed its direction of travel by DMD 831 in response to the video signal, reaches the second glass block, enters the minute gap provided between the first and second glass blocks at an angle greater than the total reflection angle, and changes its direction of travel toward the third glass block. The light traveling toward the third glass block is reflected by the red-reflecting dichroic mirror layer provided between the second and third glass blocks, changes its direction of travel, and then passes through the second glass block, the minute gap and blue-reflecting dichroic mirror layer provided between the second and first glass blocks, and the first glass block, before entering total reflection prism 811.

[0103] In addition, the blue light that has changed its direction of travel by DMD 832 in accordance with the video signal enters the first glass block, enters the tiny gap between color prism 821 and total reflection prism 811 at an angle greater than the total reflection angle, is totally reflected, travels toward the second glass block, is reflected by the blue-reflecting dichroic mirror layer provided between the first and second glass blocks, passes through the first glass block, and enters total reflection prism 811.

[0104] The light whose direction of travel has been changed in accordance with the video signal by DMDs 831, 832, and 833 enters total reflection prism 811 as described above, passes through by entering total reflection surface 812 at an angle less than the total reflection angle, exits total reflection prism 811, enters projection lens 841, and is then projected onto a screen not shown.

[0105] (Projection-type image display device employing a light source device of a second embodiment utilizing the positional relationship between an excitation light guide system and a phosphor wheel) Fig. 17 is a diagram showing a projection-type image display device employing a light source device of a second embodiment. Next, Fig. 17 shows a projection-type image display device 1700 employing a light source device 1200 of a second embodiment utilizing the positional relationship between an excitation light guide system and a phosphor wheel of the present disclosure. Note that the behavior of light up to the polarization conversion array 59 has already been explained for the light source device 1200, so a detailed explanation will be omitted.

[0106] The light having the same polarization direction over the entire wavelength range that has exited the polarization conversion array 59 is incident on a convex lens 901 .

[0107] The blue light emitted from the convex lens 901 is incident on the dichroic mirror layer 911 .

[0108] The dichroic mirror layer 911 has the property of reflecting blue light and transmitting other light (green light and red light).

[0109] The blue light incident on the dichroic mirror layer 911 is reflected, changing its direction of travel by 90 degrees, reflected by the total reflection mirror 913 arranged in the subsequent stage, changing its direction of travel by 90 degrees, passes through the convex lens 904 and the polarizing plate 921, and is guided to the LCD 931.

[0110] Next, the green light that has exited convex lens 901 is incident on dichroic mirror layer 911. As described above, dichroic mirror layer 911 has the property of transmitting green light, so the green light passes through dichroic mirror layer 911 and is incident on dichroic mirror layer 912.

[0111] Dichroic mirror layer 912 has the property of reflecting green light and transmitting red light. Green light incident on dichroic mirror layer 912 is reflected, changes its traveling direction by 90 degrees, passes through convex lens 905 and polarizing plate 923 arranged downstream, and is guided to LCD 932.

[0112] Finally, the red light that has exited convex lens 901 is incident on dichroic mirror layer 911. As described above, dichroic mirror layer 911 has the property of transmitting red light, so the red light passes through dichroic mirror layer 911 and is incident on dichroic mirror layer 912. As described above, dichroic mirror layer 912 has the property of transmitting red light, so the red light passes through dichroic mirror layer 912.

[0113] The red light passing through the dichroic mirror layer 912 has its traveling direction changed by 180 degrees by a relay lens system consisting of convex lenses 902 , 903 , and 906 and total reflection mirrors 914 and 915 , passes through a polarizing plate 925 , and is guided to an LCD 933 .

[0114] In these optical systems, the three LCDs 931, 932, and 933 are composed of multiple tiny pixels that rotate the polarization direction, and a video circuit (not shown) rotates the polarization vibration direction by 90 degrees in response to a video signal. Red light incident on LCD 933 passes through a polarizing plate 926 located downstream and is modulated in response to the video signal. Green light incident on LCD 932 passes through a polarizing plate 924 located downstream and is modulated in response to the video signal. Blue light incident on LCD 931 passes through a polarizing plate 922 located downstream and is modulated in response to the video signal.

[0115] The light transmitted through polarizing plates 922, 924, and 926 enters dichroic prism 270 from three surfaces. Dichroic prism 941 is made up of four glass blocks on which a dichroic mirror layer that reflects only blue light and a dichroic mirror layer that reflects only red light are applied, and has the property of combining the blue, green, and red light that enter from the three surfaces and outputting the combined light from the other surface.

[0116] The blue, green, and red light incident on the dichroic prism 941 are combined by the dichroic prism having the characteristics described above, exit the dichroic prism 941, enter the projection lens 951, and then projected onto a screen not shown.

[0117] (Projection-type image display device employing a light source device of a third embodiment utilizing the positional relationship between an excitation light guide system and a phosphor wheel) Fig. 18 is a diagram showing a projection-type image display device employing a light source device of a third embodiment. Next, Fig. 18 shows a projection-type image display device 1800 employing a light source device 1300 of a third embodiment utilizing the positional relationship between an excitation light guide system and a phosphor wheel of the present disclosure. Note that the behavior of light up to the rod integrator 32 has already been explained for the light source device 1300, so a detailed explanation will be omitted.

[0118] The light beams having different wavelength bands emitted from the rod integrator 32 in a time-division manner are then incident on a relay lens system consisting of three convex lenses 1001 , 1002 , and 1003 .

[0119] Light emitted from the relay lens system composed of convex lenses 1001, 1002, and 1003 enters total reflection prism 1011. Total reflection prism 1011 is composed of two prisms and a tiny gap, and the tiny gap serves as total reflection surface 1012 that reflects light that is incident at a specific angle or greater. Light that enters total reflection prism 1011 from the relay lens system composed of convex lenses 1001, 1002, and 1003 at an angle greater than the total reflection angle is totally reflected and guided to DMD 1021.

[0120] The DMD 1021 is composed of a plurality of micromirrors that correspond to pixels, and changes the direction of light travel by changing the tilt direction of the micromirrors in response to a video signal in a video circuit (not shown).

[0121] The light, whose direction of travel has changed in response to the video signal, passes through total reflection surface 1012, exits total reflection prism 1011, enters projection lens 1031, and is then projected onto a screen (not shown).

[0122] (Projection-type image display device employing a light source device of a fourth embodiment utilizing the positional relationship between an excitation light guide system and a phosphor wheel) Fig. 19 is a diagram showing a projection-type image display device employing a light source device of the fourth embodiment. Next, Fig. 19 shows a projection-type image display device 1900 employing a light source device 1400 of a fourth embodiment utilizing the positional relationship between an excitation light guide system and a phosphor wheel of the present disclosure. Note that the behavior of light up to rod integrator 32 has already been explained in light source device 1400, and the behavior after rod integrator 32 has already been explained in projection-type image display device 1800, so detailed explanations will be omitted.

[0123] (Summary of the present disclosure) Based on the above description of the present disclosure, the following techniques are disclosed.

[0124] <Technology 1> A light source device according to one aspect includes a plurality of light source units; a phosphor wheel having an annular phosphor layer that wavelength-converts light from the plurality of light source units into light of different wavelength ranges; and an excitation light guide system that guides the light from the plurality of light source units onto the phosphor layer as excitation light spots (18, 18a, 18b, 18c) that are anisotropic with respect to a geometric center and have a first axis that passes through the geometric center (Q) and is long; and a second axis that passes through the geometric center, is perpendicular to the first axis, and is shorter than the first axis. The first axis is configured to be inclined with respect to a line connecting the rotation center (C) of the phosphor wheel and the center (Q) of the excitation light spot. This configuration can reduce the integrated light intensity of the excitation light spot, even in a configuration with a plurality of light source units. Therefore, the temperature rise of the phosphor layer can be suppressed. The excitation light spot may have a rectangular shape with a long side extending in the direction of the first axis and a short side extending in the direction of the second axis. The excitation light spot may have an elliptical shape with the first axis as the major axis and the second axis as the minor axis. The excitation spot may have an intermediate shape between a rectangular shape and an elliptical shape, or may have a shape that is approximate to a rectangular shape or an elliptical shape.

[0125] <Technology 2> In the light source device described in Technology 1, the excitation light spot includes a first light intensity region (18d) and a second light intensity region (18e) that is a region with a light intensity higher than that of the first light intensity region. This makes it possible to suppress the integrated amount of light intensity of the optical excitation spot that includes the first light intensity region and the second light intensity region with a light intensity higher than that of the first light intensity region. Therefore, it is possible to suppress a temperature rise of the phosphor layer.

[0126] <Technology 3> In the light source device described in Technology 2, the major axis of the first light intensity region and the major axis of the second light intensity region are substantially perpendicular to each other. This makes it possible to suppress the integrated amount of light intensity of the optical excitation spot where the major axis of the first light intensity region and the major axis of the second light intensity region are substantially perpendicular to each other. This makes it possible to suppress the temperature rise of the phosphor layer.

[0127] <Technology 4> In the light source device described in Technology 3, the angle formed by the major axis of the second light intensity region and a diagonal line is defined as a first angle (Φ), and the angle (θ) formed by the first axis and a line connecting the rotation center of the phosphor wheel and the center of the excitation light spot is larger than the first angle (Φ). This makes it possible to suppress the integrated light intensity of an excitation light spot in which the major axis of the first light intensity region and the major axis of the second light intensity region are substantially perpendicular to each other and the angle formed by the major axis of the second light intensity region and the diagonal line is the first angle. This makes it possible to suppress a temperature rise in the phosphor layer.

[0128] <Technical Technique 5> In the light source device described in Technical Technique 4, the angle formed by the major axis of the first light intensity region and the diagonal is defined as a second angle (ω), and the angle formed by the first axis and a line connecting the rotation center of the phosphor wheel and the center of the excitation light spot is larger than the second angle (ω). This makes it possible to suppress the integrated light intensity of the optical excitation spot in which the major axis of the first light intensity region and the major axis of the second light intensity region are substantially perpendicular to each other, the angle formed by the major axis of the second light intensity region and the diagonal is a first angle, and the angle formed by the major axis of the first light intensity region and the diagonal is a second angle. This makes it possible to suppress a temperature rise in the phosphor layer.

[0129] <Technology 6> In the light source device described in any one of Techniques 3 to 5, the second light intensity regions are present at both longitudinal ends of the first light intensity region, the angle formed by the first axis and a line connecting the center (Q) of the excitation light spot and the outer vertex of the minor axis of the second light intensity region is defined as a third angle (β), and the angle formed by the first axis and a line connecting the center of rotation of the phosphor wheel and the center of the excitation light spot is smaller than the third angle (β). This makes it possible to suppress or avoid two second light intensity regions from both passing through a common region of the phosphor layer, thereby suppressing the integrated amount of light intensity of the two second light intensity regions. This therefore makes it possible to suppress a temperature rise in the phosphor layer.

[0130] <Technology 7> A projection-type image display device (for example, projector 10B) includes the light source device according to any one of technologies 1 to 6. This makes it possible to suppress a rise in temperature of the phosphor layer of the phosphor wheel in the projection-type image display device.

[0131] Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications, alterations, substitutions, additions, deletions, and equivalents within the scope of the claims, and it is understood that these also fall within the technical scope of the present disclosure. Furthermore, the components in the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0132] The technology of the present disclosure is useful for light source devices and display devices that have a phosphor wheel.

[0133] 10 Excitation light guide system 11, 41 Light source unit 111, 411 Heat sink 112, 412 Laser light source 113, 413 Collimator lens 12, 16, 17, 31, 42, 56, 61, 62, 64, 66, 68, 801, 802, 803, 901, 902, 903, 904, 905, 906, 1001, 1002, 1003 Convex lens 13, 43, 55 Concave lens 14, 44 Diffuser 15, 69 Dichroic mirror 911, 912 Dichroic mirror layer 18, 18a, 18b, 18c Excitation light spot 18d First light intensity region 18e Second light intensity region 20, 210, 220 Phosphor wheel 21, 211, 221 Rotating substrate 22, 212, 214, 222, 224 Phosphor layer 23, 213, 223 Motor 215 Opening 225 Reflective layer 30 Illumination optical system 32 Rod integrator 40 Blue optical system 54, 72 Dichroic mirror with polarization separation function 51, 71 Phase difference plate 52, 73 λ / 4 plate 53, 58, 63, 65, 67, 913, 914, 915 Total reflection mirror 57 Fly's eye lens 59 Polarization conversion array 811, 1011 Total reflection prism 812, 1012 Total reflection surface 821 Color prism 831, 832, 833, 1021 DMD 841, 951, 1031 Projection lens 921, 922, 923, 924, 925, 926 Polarizing plate 931, 932, 933 Liquid crystal panel 941 Dichroic prism 1100, 1200, 1300, 1400 Light source device 1600, 1700, 1800, 1900 Projection type image display device

Claims

A plurality of light source units; a phosphor wheel having an annular phosphor layer that converts the wavelength of light from the plurality of light source units into light of different wavelength ranges; an excitation light guide system that guides light from the plurality of light source units onto the phosphor layer as excitation light spots, the excitation light spot has a shape that is anisotropic with respect to the geometric center, in which a length in a direction of the first axis is longer than a length in a direction of the second axis, the first axis and the second axis passing through the geometric center of the excitation light spot and being orthogonal to each other; the excitation light guide system guides the excitation light spot onto the phosphor layer such that the first axis is inclined with respect to a line connecting the rotation center of the phosphor wheel and the geometric center of the excitation light spot. Light source device. 　 the excitation light spot has a rectangular shape having a long side extending in the direction of the first axis and a short side extending in the direction of the second axis; The light source device according to claim 1 . 　 the excitation light spot includes a first light intensity region and a second light intensity region that is a region having a light intensity higher than that of the first light intensity region; The light source device according to claim 2 . 　 a major axis of the first light intensity region and a major axis of the second light intensity region are substantially perpendicular to each other; The light source device according to claim 3 . 　 an angle formed by a major axis of the second light intensity region and a diagonal line is defined as a first angle; an angle formed by a line connecting the rotation center of the phosphor wheel and the center of the excitation light spot with the first axis is larger than the first angle; The light source device according to claim 4 . 　 an angle formed by a minor axis of the first light intensity region and a diagonal line is defined as a second angle; an angle formed by a line connecting the rotation center of the phosphor wheel and the center of the excitation light spot with the first axis is larger than the second angle; The light source device according to claim 5 . 　 the second light intensity region is present at both ends of the first light intensity region in the longitudinal direction, a third angle is an angle formed by a line connecting the center of the excitation light spot and an outer vertex of the minor axis of the second light intensity region and the first axis; an angle formed by a line connecting the rotation center of the phosphor wheel and the center of the excitation light spot with the first axis is smaller than the third angle; The light source device according to claim 4 . 　 A light source device comprising: a light source device according to any one of claims 1 to 7; Projection-type image display device.

Images