Light source device, projection type display device

Abstract

In the field of projection-type image display devices, which modulate and project laser light according to image signals, there has been a growing expectation for the realization of devices with less color unevenness. [Solution] The system comprises a first laser module having a plurality of first semiconductor laser elements, a second laser module having a plurality of second semiconductor laser elements, an integrator illumination system that superimposes a plurality of laser beams incident on the incident surface and emits them from the exit surface, and a correction optical system. Each of the plurality of first semiconductor laser elements has one light-emitting part and emits laser light of a first wavelength, and each of the plurality of second semiconductor laser elements has two light-emitting parts and emits laser light of a second wavelength. The correction optical system is an optical system that approximates the intensity distribution of the laser beam incident on the incident surface of the integrator illumination system from the first laser module to the intensity distribution of the laser beam incident on the incident surface of the integrator illumination system from the second laser module.

Description

Technical Field

[0001] The present invention relates to a light source device and a projection display device including the light source device.

Background Art

[0002] Conventionally, a projection display device using laser light has been known. Patent Document 1 discloses a projection display device including a laser light source, an acousto-optic modulator that modulates laser light according to a video signal, a polygonal mirror that horizontally scans the modulated laser light, and a galvanometer mirror that vertically scans the modulated laser light.

[0003] Patent Document 2 discloses a compact projection display device capable of projecting an image by irradiating a reflective light modulation element with laser light from three-color laser light sources through an integrator illumination system.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the projection display device described in Patent Document 1, although it includes optical scanning means that combines a polygonal mirror for horizontal scanning and a galvanometer mirror for vertical scanning, since both horizontal and vertical directions are optically scanned, a large optical path space is required, and there is a problem that the device becomes large.

[0006] While the projection display device described in Patent Document 2 can be configured as a compact device, achieving high brightness may result in uncontrolled color unevenness. This is because, generally, with blue (B) and green (G) semiconductor laser elements, the light emission intensity of the light-emitting part can be increased, so sufficient brightness can be obtained with one light-emitting part per element. On the other hand, with red (R) semiconductor laser elements, the light emission intensity of the light-emitting part is relatively smaller compared to blue (B) and green (G) semiconductor laser elements, making it difficult to obtain sufficient brightness with one light-emitting part per element.

[0007] Although not described in Patent Document 2, in order to ensure white balance when illuminating by synthesizing laser light of each color, semiconductor laser elements having one light-emitting part per element may be used for blue light (B) and green light (G), and semiconductor laser elements having two light-emitting parts per element may be used for red light (R).

[0008] The problems encountered when illuminating a reflective optical modulation element through an integrator illumination system using these three-color semiconductor laser elements will be explained with reference to Figures 10(a) to 11(b). For red light (R), as shown in Figure 10(a), a laser module consisting of 2 × 4 semiconductor lasers 11A, each having two light-emitting parts 12 per element, will be used. For blue light (B) and green light (G), as shown in Figure 10(b), a laser module consisting of 2 × 4 semiconductor lasers 11B, each having one light-emitting part 12 per element, will be used.

[0009] Figure 11(a) schematically shows how the laser beams emitted from each semiconductor laser 11A, which emits red light (R) from a laser module having two light-emitting parts, are focused near the incident surface INP of the integrator illumination system (e.g., rod 105). A collimating lens 101 is positioned corresponding to each semiconductor laser 11A, and the laser beam emitted from the laser module is focused near the incident surface INP by a focusing lens 103. A diffuser plate 104 is positioned near the incident surface INP. The lower part of Figure 11(a) schematically shows images of the two light-emitting parts focused on the incident surface INP.

[0010] Figure 11(b) schematically shows how laser beams emitted from blue (B) and green (G) laser modules, each having a single light-emitting unit, are focused near the incident surface INP of the integrator illumination system (e.g., rod 105). A collimating lens 101 is positioned corresponding to each semiconductor laser 11B, and the laser beam emitted from the laser module is focused near the incident surface INP by a focusing lens 103. A diffuser plate 104 is positioned near the incident surface INP. The lower part of Figure 11(b) schematically shows an image of a single light-emitting unit focused on the incident surface INP.

[0011] As can be seen from the figure, the brightness distribution and directivity of the laser light incident on the incident surface INP of the integrator illumination system differ between the red light (R) output from the semiconductor laser 11A having two light-emitting parts and the blue light (B) and green light (G) output from the semiconductor laser 11B having one light-emitting part. This difference in brightness distribution and directivity cannot be completely eliminated by providing a diffuser plate 104 near the incident surface INP.

[0012] The laser light incident on the incident surface INP is repeatedly reflected by the inner surface of the rod 105 of the integrator illumination system and emitted from the exit surface EXP. However, the in-plane distribution of emitted light intensity differs between red light (R), blue light (B), and green light (G). Figure 10(c) is a graph illustrating the light intensity distribution emitted from the exit surface EXP. The solid line graph shows the light intensity distribution of blue light (B) and green light (G), while the dotted line graph shows the light intensity distribution of red light (R).

[0013] Thus, if the in-plane intensity distribution of the illumination laser light differs for each color at the output surface EXP of the integrator illumination system, the intensity distribution of each color of light is directly transferred by the transfer optical system when illuminating the reflective optical modulation element, which can result in color unevenness in the displayed image.

[0014] Therefore, in the field of projection-type image display devices that modulate and project laser light according to an image signal, there was a desire to realize a device with less color unevenness. [Means for solving the problem]

[0015] One aspect of the present invention is a light source device comprising: a first laser module having a plurality of first semiconductor laser elements; a second laser module having a plurality of second semiconductor laser elements; an integrator illumination system that superimposes a plurality of laser beams incident on an incident surface and emits them from an exit surface; and a correction optical system, wherein each of the plurality of first semiconductor laser elements has one light-emitting part per element and emits laser light of a first wavelength; each of the plurality of second semiconductor laser elements has two light-emitting parts per element and emits laser light of a second wavelength; the intensity distribution of the laser beam incident on the incident surface of the integrator illumination system from the second laser module has two peaks aligned along one side of the incident surface; at the position of the peaks, the laser beam has a spot shape with its longitudinal direction aligned along the one side of the incident surface; and the correction optical system is an optical system that approximates the intensity distribution of the laser beam incident on the incident surface of the integrator illumination system from the first laser module to the intensity distribution of the laser beam incident on the incident surface of the integrator illumination system from the second laser module. [Effects of the Invention]

[0016] According to the present invention, in the field of projection-type image display devices that modulate and project laser light according to an image signal, it is possible to realize a device with less color unevenness. [Brief explanation of the drawing]

[0017] [Figure 1] A schematic diagram showing the optical path from the blue light (B) and green light (G) laser modules to the rod of the integrator illumination system, as viewed from the Y direction, in the illumination device according to Embodiment 1. [Figure 2](a) A schematic diagram of the optical path from the L-row semiconductor laser 11B of the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system, as viewed from the X direction, in Embodiment 1. (b) A schematic diagram of the optical path from the R-row semiconductor laser 11B of the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system, as viewed from the X direction, in Embodiment 1. (c) A schematic diagram showing how the laser beam is focused onto the incident surface INP of the integrator illumination system, in Embodiment 1. [Figure 3] This figure shows the light intensity distribution of the laser beam emitted from the exit surface EXP of rod 105 of the integrator illumination system. [Figure 4] (a) A schematic diagram of the optical path from the L-row semiconductor laser 11B of the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system, as viewed from the X direction, in Embodiment 2. (b) A schematic diagram of the optical path from the R-row semiconductor laser 11B of the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system, as viewed from the X direction, in Embodiment 2. (c) A schematic diagram showing how the laser beam is focused onto the incident surface INP of the integrator illumination system, in Embodiment 2. [Figure 5] (a) A schematic diagram of the optical path from the L-row semiconductor laser 11B of the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system, as viewed from the X direction, in Embodiment 3. (b) A schematic diagram of the optical path from the R-row semiconductor laser 11B of the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system, as viewed from the X direction, in Embodiment 3. (c) A schematic diagram showing how the laser beam is focused onto the incident surface INP of the integrator illumination system, in Embodiment 3. [Figure 6](a) In Embodiment 4, a schematic diagram of the optical path from the semiconductor laser 11B in the L column of the laser modules for blue light (B) and green light (G) to the rod 105 of the integrator illumination system, as viewed from the X direction. (b) In Embodiment 4, a schematic diagram of the optical path from the semiconductor laser 11B in the R column of the laser modules for blue light (B) and green light (G) to the rod 105 of the integrator illumination system, as viewed from the X direction. (c) In Embodiment 4, a diagram schematically showing that the laser beam is focused on the incident surface INP of the integrator illumination system. [Figure 7] (a) A diagram showing a bulk rod used in the integrator illumination system. (b) A diagram showing a hollow rod used in the integrator illumination system. [Figure 8] A diagram showing a schematic configuration of an optical system of a projection display device according to Embodiment 5. [Figure 9] A diagram showing a schematic configuration of an optical system of a projection display device according to Embodiment 6. [Figure 10] (a) A diagram showing a laser module for red light (R). (b) A diagram showing laser modules for blue light (B) and green light (G). (c) A graph illustrating the light intensity distribution emitted from the exit surface EXP of a conventional integrator illumination system. [Figure 11] (a) A diagram showing an illumination system for red light (R). (b) A diagram showing conventional illumination systems for blue light (B) and green light (G).

Embodiments for Carrying Out the Invention

[0018] Referring to the drawings, a light source device and a projection display device, which are embodiments of the present invention, will be described. Note that the embodiments shown below are examples, and for example, regarding the detailed configuration, those skilled in the art can appropriately modify and implement it within the scope not departing from the gist of the present invention. In the drawings referred to in the following description, unless otherwise specified, elements denoted by the same reference numerals have the same functions. Note that since the optical elements in the drawings are schematically represented, the actual shape and configuration are not necessarily faithfully represented. For example, even if it is drawn as a single lens in the drawing, unless otherwise specified, it may be composed of a plurality of lenses.

[0019] In the following explanation, for example, when we refer to the "X-plus direction," it refers to the same direction as the X-axis arrow in the illustrated coordinate system, and when we refer to the "X-minus direction," it refers to the direction 180 degrees opposite to the direction the X-axis arrow in the illustrated coordinate system points to. Furthermore, when we simply refer to the "X direction," it refers to the direction parallel to the X-axis, regardless of whether it is the same as or different from the direction the X-axis arrow points to in the illustrated coordinate system. The same applies to directions other than X.

[0020] Furthermore, in the following explanation, red may be referred to as "R," green as "G," and blue as "B." Therefore, for example, R light is synonymous with red light, G light source with green light source, and B laser with blue laser. Also, when describing optical elements corresponding to a specific color, letters to specify the color may be added, for example, B light source 100B, B deflector 210B. On the other hand, when describing common aspects for each color, the colors may be described collectively without distinction, for example, light source 100, deflector 210.

[0021] In the embodiments of the present invention described below, a laser module is used as an illumination light source, comprising a plurality of first semiconductor laser elements, each having one light-emitting part and emitting light at a first wavelength (e.g., B or G), and a plurality of second semiconductor laser elements, each having two light-emitting parts and emitting light at a second wavelength (e.g., R).

[0022] In this embodiment, a corrective optical system is used to adjust the optical path of the laser beam emitted from the first wavelength laser module, so that the intensity distribution (or incident angle distribution) of the laser beam incident on the incident surface INP of the integrator illumination system approximates the intensity distribution (or incident angle distribution) of the laser beam incident on the incident surface INP from the second wavelength laser module.

[0023] In other words, the optical path of the laser light emitted from a laser module equipped with multiple first semiconductor laser elements, each having one light-emitting element, is adjusted to approximate the intensity distribution (or incident angle distribution) of the laser light incident on the incident surface INP of the integrator illumination system to the intensity distribution (or incident angle distribution) of the laser light incident on the incident surface INP from a laser module equipped with multiple second semiconductor laser elements, each having two light-emitting elements.

[0024] This makes it possible to suppress differences in the light intensity distribution within the screen between the second wavelength (e.g., R) laser light and the first wavelength (e.g., B or G) laser light that illuminate the optical modulation element, thereby realizing a projection display device with less color unevenness.

[0025] Furthermore, for details regarding the configuration and operation of the integrator illumination system / optical superposition means, refer to, for example, Japanese Patent Publication No. 2023-143587 mentioned above, or other documents.

[0026] [Embodiment 1] In the light source device according to this embodiment, for red light (R), a laser module is used in which 2 × 4 semiconductor lasers 11A, each having two light-emitting units 12 per element, are arranged, as shown in Figure 10(a). For blue light (B) and green light (G), a laser module is used in which 2 × 4 semiconductor lasers 11B, each having one light-emitting unit 12 per element, are arranged, as shown in Figure 10(b). The light-emitting units 12 of each color semiconductor laser are not point sources, but are essentially linear light sources with their longitudinal direction in the Y direction, and the length in the longitudinal direction is Hy1. In the semiconductor laser 11A having two light-emitting units 12, the two light-emitting units 12 are arranged along the longitudinal direction of the light-emitting unit 12 (longitudinal direction of light-emitting unit = Y direction). For convenience of explanation, a row of four semiconductor lasers arranged along the Y direction within the laser module is treated as a group, and when distinguishing between the groups, they may be called L-row and R-row as shown in the figure. Each of the L-row and R-row consists of a group of semiconductor lasers arranged along the longitudinal direction of the light-emitting unit 12.

[0027] In this embodiment, the optical paths of the laser beams output from blue (B) and green (G) laser modules, each equipped with a semiconductor laser 11B having one light-emitting element 12 per element, are adjusted using wedge prisms. Wedge prisms are positioned in different orientations corresponding to the L and R rows of the semiconductor laser. No wedge prisms are placed in the optical path of the laser beams output from the red (R) laser module, which is equipped with a semiconductor laser 11A having two light-emitting elements 12 per element, and the configuration is as shown in Figure 11(a).

[0028] Figure 1 is a schematic diagram of the optical path from the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system in the illumination device according to Embodiment 1, as viewed from the Y direction. The two spots of the laser beam focused on the incident surface INP of the integrator illumination system are schematically shown at the bottom of the optical path diagram.

[0029] Figure 2(a) is a schematic diagram of the optical path from the L-row semiconductor lasers 11B of the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system, as viewed from the X direction. A wedge prism WPL, which deflects the laser beam in the Y-positive direction, is positioned between the collimating lens 101 and the focusing lens 103 in the optical path of the laser light output from the L-row semiconductor lasers 11B.

[0030] Figure 2(b) is a schematic diagram of the optical path from the R-row semiconductor laser 11B of the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system, viewed from the X direction. A wedge prism WPR, which deflects the laser beam in the Y-minus direction, is positioned between the collimating lens 101 and the focusing lens 103 in the optical path of the laser light output from the R-row semiconductor laser 11B.

[0031] Figure 2(c) schematically shows how the L-row laser beams, deflected by a wedge prism (WPL), are focused to the Y-positive side at the incident surface INP of the integrator illumination system, and how the R-row laser beams, deflected by a wedge prism (WPR), are focused to the Y-negative side at the incident surface INP of the integrator illumination system. For blue light (B) and green light (G), as shown in Figure 2(c), the irradiation positions of the L-row and R-row laser beams can be moved in opposite directions along one side (e.g., the longer side) of the incident surface INP to focus them to completely separate positions. However, in some cases, the irradiation positions of the L-row and R-row laser beams may not be completely separated, and they may be focused so that parts of their irradiation spots overlap. In other words, the intensity distribution of the laser beam incident on the incident surface INP of the integrator illumination system from the second laser module (G or B) has two peaks aligned along one side (e.g., the long side) of the incident surface INP, and the spot shape of the laser beam constituting each peak has its longitudinal direction aligned with one side (e.g., the long side) of the incident surface INP.

[0032] As can be seen from these figures, according to this embodiment, a wedge prism is placed in the optical path of the laser light emitted from a laser module equipped with multiple semiconductor lasers (B or G) each having one light-emitting element, thereby adjusting the optical path to approximate the intensity distribution (or incident angle distribution) of the laser light incident on the incident surface INP by a laser module equipped with multiple semiconductor lasers (R) each having two light-emitting elements.

[0033] As a result, as shown in Figure 3, the light intensity distribution of the laser light emitted from the exit surface EXP of the rod 105 of the integrator illumination system is extremely similar between the blue light (B) or green light (G) emitted from a semiconductor laser having one light-emitting part per element and the red light (R) emitted from a semiconductor laser having two light-emitting parts per element. In other words, the light source device according to this embodiment can provide illumination light in which the light intensity distribution of each color component is extremely similar on the screen of the reflective optical modulation element.

[0034] The above description illustrates a light source device in which laser light of each color forms two bright spots aligned along the Y direction (i.e., the longitudinal direction of the light-emitting unit 12) on the incident surface INP of the integrator illumination system. When such a light source device is used as an illumination source for a display device, the illumination optical system can be configured such that the direction in which the two bright spots are aligned on the incident surface INP of the integrator illumination system corresponds to the longitudinal direction (generally the horizontal direction H) of the rectangular display screen (or the rectangular screen of the reflective optical modulation element).

[0035] Furthermore, the rod 105 exemplified as an optical element for the integrator illumination system can be any optical element capable of totally reflecting incident light on its side surface, for example, those shown in Figure 7(a) or Figure 7(b) can be used. Preferably, the rod 105 is configured such that the shape of the incident surface INP, the shape of the exit surface EXP, and the cross-sectional shape of the rod portion are the same.

[0036] The rod 105 shown in Figure 7(a) is a solid rectangular prism-shaped element made of an optical material such as optical glass or a translucent resin, and the end faces, the incident surface INP and the exit surface EXP, are rectangles with the long side H0 and the short side V0. It is desirable to apply an anti-reflective coating (AR coating) to the incident surface INP and the exit surface EXP.

[0037] Furthermore, the rod 105 shown in Figure 7(b) is a hollow rectangular prism, i.e., a cylindrical element, and a reflective surface made of, for example, aluminum, is formed on the inner surface of the cylinder. The shape of the incident surface INP and the exit surface EXP, which are the openings of the cylinder, is a rectangle with the long side H0 and the short side V0. For example, it can be manufactured relatively inexpensively by depositing a reflective film such as an aluminum film onto a glass or metallic plate-shaped substrate, and then assembling the substrate into a cylindrical shape by bonding the substrates together.

[0038] As described above, the shapes of the inlet surface INP and outlet surface EXP of the rod 105 are rectangles with the long side H0 and the short side V0. However, for example, the shapes of the inlet surface INP and outlet surface EXP of the rod 105 can be rectangles with the X direction (short side V0) being 0.33 mm and the Y direction (long side H0) being 1.67 mm.

[0039] [Embodiment 2] In Embodiment 1, a wedge prism WPL is placed on the optical path of the laser beam output from the L-row semiconductor laser 11B to deflect the laser beam in the Y-positive direction, and a wedge prism WPR is placed on the optical path of the laser beam output from the R-row semiconductor laser 11B to deflect the laser beam in the Y-minus direction. However, the means of approximating the intensity distribution (or incident angle distribution) of the blue light (B) and green light (G) incident on the incident surface INP of the integrator illumination system to that of the red light (R) is not limited to the wedge prisms of the form exemplified in Embodiment 1.

[0040] Embodiment 2 will be described with reference to Figures 4(a) to 4(c). The explanation of matters common to Embodiment 1 will be simplified or omitted.

[0041] Figure 4(a) is a schematic diagram of the optical path from the L-row semiconductor lasers 11B of the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system, as viewed from the X direction. Between the collimating lens 101 and the focusing lens 103, a prism array PAL is positioned in the optical path of the laser light output from the L-row semiconductor lasers 11B. When viewed in the Y-minus direction, the odd-numbered laser beams are deflected in the Y-plus direction, and the even-numbered laser beams are deflected in the Y-minus direction.

[0042] Figure 4(b) is a schematic diagram of the optical path from the R-row semiconductor lasers 11B of the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system, as viewed from the X direction. A prism array PAR is positioned between the collimating lens 101 and the focusing lens 103 on the optical path of the laser light output from the R-row semiconductor lasers 11B. When viewed in the Y-minus direction, the odd-numbered laser beams are deflected in the Y-minus direction, and the even-numbered laser beams are deflected in the Y-plus direction.

[0043] Figure 4(c) schematically shows how the laser beams deflected by the prism array PAL and prism array PAR are focused at two locations on the incident surface INP of the integrator illumination system, on the Y-positive and Y-negative sides. The intensity distribution of the laser beam incident on the incident surface INP of the integrator illumination system from the second laser module (G or B) has two peaks aligned along one side (e.g., the long side) of the incident surface INP, and at the position of each peak, the laser beam has a spot shape with its longitudinal direction aligned along one side (e.g., the long side) of the incident surface INP.

[0044] In this embodiment, a prism array is placed on the optical path of laser light emitted from a laser module equipped with multiple semiconductor lasers (B or G) each having one light-emitting element, thereby adjusting the optical path to approximate the intensity distribution (or incident angle distribution) of laser light incident on the incident surface INP by a laser module equipped with multiple semiconductor lasers (R) each having two light-emitting elements.

[0045] As a result, similar to Embodiment 1, the light intensity distribution of the laser light emitted from the exit surface EXP of the rod 105 of the integrator illumination system is extremely similar for the blue light (B) and green light (G) irradiated from a semiconductor laser having one light-emitting part per element, and the red light (R) irradiated from a semiconductor laser having two light-emitting parts per element. In other words, the light source device according to this embodiment can provide illumination light in which the light intensity distribution of each color component is extremely similar on the screen of the reflective optical modulation element.

[0046] In addition, while the example shown for the prism array is one in which microprisms are arranged to deflect odd-numbered and even-numbered laser beams in opposite directions when viewed in the Y-minus direction, the configuration of the prism array is not limited to this example. For example, a predetermined number of laser beams aligned in the Y direction may be grouped together, and each group may be configured to deflect the laser beams in opposite directions. Alternatively, prism arrays of the same configuration may be installed in the L and R columns. The point is that the deflection direction is set corresponding to each semiconductor laser, each having one light-emitting element, and the intensity distribution (or incident angle distribution) of the laser light is concentrated in two places along one side (e.g., the long side) of the incident surface INP of the integrator illumination system.

[0047] The above description illustrates a light source device in which laser light of each color forms two bright spots aligned along the Y direction (i.e., the longitudinal direction of the light-emitting unit 12) on the incident surface INP of the integrator illumination system. When such a light source device is used as an illumination source for a display device, the illumination optical system can be configured such that the direction in which the two bright spots are aligned on the incident surface INP of the integrator illumination system corresponds to the longitudinal direction (generally the horizontal direction H) of the rectangular display screen (or the rectangular screen of the reflective optical modulation element).

[0048] [Embodiment 3] Further means may be used to approximate the intensity distribution (or incident angle distribution) of the blue light (B) and green light (G) incident on the incident surface INP of the integrator illumination system to that of the red light (R). Embodiment 3 will be described with reference to Figures 5(a) to 5(c). Matters common to Embodiment 1 will be simplified or omitted from the explanation.

[0049] In this embodiment, instead of focusing the laser beams output from the semiconductor lasers in rows L and R near the incident surface INP of the integrator illumination system using a common focusing lens 103, the laser beam from row L is focused with focusing lens 103L, and the laser beam from row R is focused with focusing lens 103R. Focusing lenses 103L and 103R are positioned shifted relative to each other in the Y direction.

[0050] Figure 5(a) is a schematic diagram of the optical path from the L-row semiconductor lasers 11B of the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system, as viewed from the X direction. A focusing lens 103L is provided on the optical path of the laser light output from the L-row semiconductor lasers 11B at a position shifted to the Y-positive side compared to the focusing lens 103 of Embodiment 1.

[0051] Furthermore, Figure 5(b) is a schematic diagram of the optical path from the R-row semiconductor laser 11B of the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system, as viewed from the X direction. A focusing lens 103R is provided on the optical path of the laser light output from the R-row semiconductor laser 11B at a position shifted to the Y-minus side compared to the focusing lens 103 of Embodiment 1.

[0052] Figure 5(c) schematically shows how the laser beams that have passed through the focusing lenses 103L and 103R are focused at two locations on the incident surface INP of the integrator illumination system, on the Y-positive and Y-negative sides. The intensity distribution of the laser beam incident on the incident surface INP of the integrator illumination system from the second laser module (G or B) has two peaks aligned along one side (e.g., the long side) of the incident surface INP, and at the peak positions, the laser beam has a spot shape with its longitudinal direction aligned with one side (e.g., the long side) of the incident surface INP.

[0053] In this embodiment, a divided focusing lens is placed on the optical path of laser light emitted from a laser module equipped with multiple semiconductor lasers (B or G) each having one light-emitting element, thereby adjusting the optical path to approximate the intensity distribution (or incident angle distribution) of laser light incident on the incident surface INP by a laser module equipped with multiple semiconductor lasers (R) each having two light-emitting elements.

[0054] As a result, similar to Embodiment 1, the light intensity distribution of the laser light emitted from the exit surface EXP of the rod 105 of the integrator illumination system is extremely similar for the blue light (B) and green light (G) irradiated from a semiconductor laser having one light-emitting part per element, and the red light (R) irradiated from a semiconductor laser having two light-emitting parts per element. In other words, the light source device according to this embodiment can provide illumination light in which the light intensity distribution of each color component is extremely similar on the screen of the reflective optical modulation element.

[0055] The above description illustrates a light source device in which laser light of each color forms two bright spots aligned along the Y direction (i.e., the longitudinal direction of the light-emitting unit 12) on the incident surface INP of the integrator illumination system. When such a light source device is used as an illumination source for a display device, the illumination optical system can be configured such that the direction in which the two bright spots are aligned on the incident surface INP of the integrator illumination system corresponds to the longitudinal direction (generally the horizontal direction H) of the rectangular display screen (or the rectangular screen of the reflective optical modulation element).

[0056] [Embodiment 4] Further means may be used to approximate the intensity distribution (or incident angle distribution) of blue light (B) and green light (G) incident on the incident surface INP of the integrator illumination system to that of red light (R). Embodiment 4 will be described with reference to Figures 6(a) to 6(c). Matters common to Embodiment 1 will be simplified or omitted from the explanation.

[0057] This embodiment includes fixing means for fixing the semiconductor laser modules in column L and the laser modules in column R at an angle to each other.

[0058] Figure 6(a) is a schematic diagram of the optical path from the semiconductor laser 11B in row L of the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system, as viewed from the X direction. In row L, the laser module LML is tilted and fixed so that the laser beam does not travel parallel to the Z direction, but rather travels with a Y-positive component.

[0059] Figure 6(b) is a schematic diagram of the optical path from the semiconductor laser 11B in the R column of the blue light (B) and green light (G) laser modules to the rod 105 of the integrator illumination system, as viewed from the X direction. In the R column, the laser module LMR is tilted and fixed so that the laser beam does not travel parallel to the Z direction, but rather travels with a component in the Y-negative direction.

[0060] Figure 6(c) schematically shows how the laser beams emitted from the laser module LML and the laser module LMR are focused by the focusing lens 103 to two locations on the incident surface INP of the integrator illumination system, one on the Y-positive side and the other on the Y-minus side. The intensity distribution of the laser beam incident on the incident surface INP of the integrator illumination system from the second laser module (G or B) has two peaks aligned along one side (e.g., the long side) of the incident surface INP, and at the position of the peaks, the laser beam has a spot shape with its longitudinal direction aligned with one side (e.g., the long side) of the incident surface INP.

[0061] In this embodiment, a laser module having a semiconductor laser (B or G) with one light-emitting element per element is divided, and the divided laser modules are tilted relative to each other to adjust the direction of laser beam emission, thereby approximating the intensity distribution (or incident angle distribution) of laser beam incident on the incident surface INP by a laser module equipped with multiple semiconductor lasers (R) having two light-emitting elements per element.

[0062] As a result, similar to Embodiment 1, the light intensity distribution of the laser light emitted from the exit surface EXP of the rod 105 of the integrator illumination system is extremely similar for the blue light (B) and green light (G) irradiated from a semiconductor laser having one light-emitting part per element, and the red light (R) irradiated from a semiconductor laser having two light-emitting parts per element. In other words, the light source device according to this embodiment can provide illumination light in which the light intensity distribution of each color component is extremely similar on the screen of the reflective optical modulation element.

[0063] The above description illustrates a light source device in which laser light of each color forms two bright spots aligned along the Y direction (i.e., the longitudinal direction of the light-emitting unit 12) on the incident surface INP of the integrator illumination system. When such a light source device is used as an illumination source for a display device, the illumination optical system can be configured such that the direction in which the two bright spots are aligned on the incident surface INP of the integrator illumination system corresponds to the longitudinal direction (generally the horizontal direction H) of the rectangular display screen (or the rectangular screen of the reflective optical modulation element).

[0064] [Embodiment 5] A projection-type image display device equipped with the light source device according to the above-described embodiment will now be explained. Here, a projection-type image display device equipped with the light source device according to Embodiment 1 will be given as an example, but it goes without saying that a light source device according to any of Embodiments 2 to 4 may be used instead of Embodiment 1. Regarding the light source device, matters that have already been explained will be simplified or omitted.

[0065] Figure 8 shows a schematic configuration of the optical system of the projection display device 1000 according to Embodiment 5. For the sake of clarity, the figure omits mechanical mechanisms for mounting the optical elements, as well as the housing and electrical wiring.

[0066] The projection display device 1000 includes a B light source, a G light source, an R light source, a dichroic mirror 221, a dichroic mirror 222, a focusing lens 103, a diffuser plate 104, a rod 105 of the integrator illumination system, a front transfer lens 201 and a rear transfer lens 202 constituting the transfer optical system, an optical path conversion mirror 330, a TIR prism 350, a reflective light modulation element 340, and a projection lens 360. The projection display device 1000 may optionally include a projection screen 190.

[0067] As described in Embodiment 1, the B light source and the G light source use semiconductor lasers having one light-emitting element 12 per element, while the R light source uses a semiconductor laser having two light-emitting elements 12 per element. The laser module LM-B of the B light source and the laser module LM-B of the G light source are each provided with a wedge prism WPR and a wedge prism WPL, as described in Embodiment 1. The laser module LM-R of the R light source is not provided with a wedge prism.

[0068] To miniaturize the device and reduce the number of parts, the optical paths of the B light source, G light source, and R light source are combined using dichroic mirrors 221 and 222, and the focusing lens, diffuser plate 104, and rod 105 are shared for each color. The dichroic mirror 221 has optical properties that transmit G light and reflect R light, while the dichroic mirror 222 has optical properties that transmit G and R light and reflect B light.

[0069] The optical image from the exit surface EXP of the integrator illumination system (rod 105) is magnified and transferred onto the screen of the reflective optical modulator 340 by the front transfer lens 201 and rear transfer lens 202, which constitute the transfer optical system. The magnification of the transfer is, for example, about 6 times. The front transfer lens 201 and the rear transfer lens 202 are convex lenses with positive power.

[0070] To miniaturize the device, the illumination light's path is changed by the optical path conversion mirror 330 and then incident on the TIR prism 350. The TIR prism 350 is an internal total internal reflection prism, for example, composed of two prisms combined together, which causes the illumination light (B light, G light, R light) to undergo total internal reflection at the air gap surface and incident on the reflective optical modulation element 340 at a predetermined angle.

[0071] For the reflective optical modulation element 340, a DMD (Direct-Modulated Display) is used, for example, which has an array of micromirror devices. Each micromirror corresponding to a display pixel is driven so that its reflection direction is changed by pulse width modulation according to the brightness level of the video signal. However, it is also possible to use a different type of reflective optical modulation device, such as a reflective liquid crystal device.

[0072] The image light passes through the TIR prism 350 and is guided to the projection lens 360 for projection. The projection lens 360 consists of one or more lenses and may also have autofocus and zoom functions.

[0073] The projection screen 190 is used when configuring a rear projection type display device. It is also often installed in front projection type displays, but it is not always necessary to install it when the user projects onto a wall or other surface of their choice.

[0074] When displaying a monochrome (black and white) image with the projection display device 1000, the G light source, B light source, and R light source are simultaneously lit to illuminate the reflective light modulation element 340 with white light, thereby enabling the projection of a display image with high brightness and minimal coloration.

[0075] Furthermore, when displaying a color image with the projection display device 1000, the G light source, B light source, and R light source are sequentially lit in a time-division manner to illuminate the reflective light modulation element 340. The reflective light modulation element 340 modulates according to the brightness levels of the G, B, and R components of the video signal in synchronization with the switching of the illumination light color, thereby enabling the projection of a display image with high brightness and minimal color unevenness.

[0076] According to this embodiment, the optical path of the laser light emitted from a laser module equipped with multiple semiconductor lasers, each having one light-emitting element, is adjusted to approximate the intensity distribution (or incident angle distribution) of the laser light incident on the incident surface INP of the integrator illumination system to the intensity distribution (or incident angle distribution) of the laser light incident on the incident surface INP from a laser module equipped with multiple semiconductor lasers, each having two light-emitting elements. As a result, the light intensity distribution of the laser light emitted from the exit surface EXP of the rod 105 of the integrator illumination system becomes extremely similar between the blue light (B) and green light (G) irradiated from the semiconductor lasers, each having one light-emitting element, and the red light (R) irradiated from the semiconductor lasers, each having two light-emitting elements. This suppresses differences in the light intensity distribution within the screen between the first wavelength (e.g., R) laser light and the second wavelength (e.g., B or G) laser light illuminating the optical modulation element, enabling the realization of a projection display device with less color unevenness.

[0077] [Embodiment 6] Another embodiment of the projection-type image display device equipped with the light source device according to the above-described embodiment will now be explained. Here, a projection-type image display device equipped with the light source device according to Embodiment 1 will be given as an example, but it goes without saying that a light source device according to any of Embodiments 2 to 4 may be used instead of Embodiment 1. Regarding the light source device, matters that have already been explained will be simplified or omitted.

[0078] Figure 9 shows a schematic configuration of the optical system of the projection-type display device 2000 according to Embodiment 6. For the sake of clarity, the figure omits mechanical mechanisms for mounting the optical elements, as well as the housing and electrical wiring.

[0079] The projection-type display device 2000 comprises a B light source 100B, a G light source 100G, an R light source 100R, a B deflector 210B, a G deflector 210G, an R deflector 210R, a photosynthesis unit 220, an optical path conversion mirror 330, a TIR prism 350, a reflective optical modulation element 340, and a projection lens 360. A front transfer lens 201 is positioned between each color light source and each color deflector, and a rear transfer lens 202 is positioned between the photosynthesis unit 220 and the optical path conversion mirror 330. The photosynthesis unit 220 includes a dichroic mirror 221 and a dichroic mirror 222. The projection-type display device 2000 can optionally include a projection screen 190.

[0080] The basic configuration and operation of the projection display device 2000, including the deflector, can be easily understood by referring to the information described in Japanese Patent Publication No. 2023-143587.

[0081] However, in the projection display device 2000 of this embodiment, the laser module LM-B for the B light source and the laser module LM-B for the G light source are each provided with a wedge prism WPR and a wedge prism WPL, as described in Embodiment 1. The laser module LM-R for the R light source is not provided with a wedge prism.

[0082] According to this embodiment, the optical path of the laser light emitted from a laser module equipped with multiple semiconductor lasers, each having one light-emitting element, is adjusted to approximate the intensity distribution (or incident angle distribution) of the laser light incident on the incident surface INP of the integrator illumination system to the intensity distribution (or incident angle distribution) of the laser light incident on the incident surface INP from a laser module equipped with multiple semiconductor lasers, each having two light-emitting elements.

[0083] As a result, the light intensity distribution of the laser light emitted from the exit surface EXP of the rod 105 of the integrator illumination system is extremely similar between the blue light (B) and green light (G) emitted from a semiconductor laser having one light-emitting part per element, and the red light (R) emitted from a semiconductor laser having two light-emitting parts per element. This suppresses differences in light intensity distribution within the screen between the first wavelength (e.g., R) laser light and the second wavelength (e.g., B or G) laser light illuminating the optical modulation element, enabling the realization of a projection display device with less color unevenness.

[0084] [Other embodiments] It should be noted that the present invention is not limited to the embodiments described above, and many modifications are possible within the technical concept of the present invention. For example, all or part of the different embodiments described above may be combined and implemented.

[0085] For example, the rod of the integrator lighting system was given as an example in which the shape of the incident surface INP, the shape of the exit surface EXP, and the cross-sectional shape of the rod portion are the same. However, a rod in which the shape of the incident surface INP and the shape of the exit surface EXP are different, such as a so-called tapered rod, may also be used.

[0086] This specification discloses at least the following: [Item 1] A first laser module having multiple first semiconductor laser elements, A second laser module having multiple second semiconductor laser elements, An integrator illumination system that superimposes multiple laser beams incident on the incident surface and emits them from the exit surface, Equipped with a corrective optical system, Each of the plurality of first semiconductor laser elements is equipped with one light-emitting unit per element and emits laser light of a first wavelength. Each of the plurality of second semiconductor laser elements is equipped with two light-emitting units and emits laser light of a second wavelength. The intensity distribution of the laser beam incident on the incident surface of the integrator illumination system from the second laser module has two peaks aligned along one side of the incident surface, and at the position of the peaks, the laser beam has a spot shape whose longitudinal direction is aligned along the one side of the incident surface. The correction optical system is an optical system that approximates the intensity distribution of the laser beam incident on the incident surface of the integrator illumination system from the first laser module to the intensity distribution of the laser beam incident on the incident surface of the integrator illumination system from the second laser module. A light source device characterized by the following features. [Matter 2] In the first laser module, the longitudinal directions of the light-emitting portions of each of the plurality of first semiconductor laser elements are oriented in the same direction. In the second laser module, the longitudinal direction of the light-emitting portion of each of the plurality of second semiconductor laser elements is oriented in the same direction. The aforementioned corrective optical system is The optical path of the laser beam emitted from the first laser module is corrected so that the intensity distribution of the laser beam incident on the incident surface from the first laser module has two peaks aligned along one side of the incident surface. A light source device as described in item 1, characterized by the features described above. [Matter 3] The aforementioned corrective optical system is The irradiation position of the laser beam emitted from some of the multiple first semiconductor laser elements and the irradiation position of the laser beam emitted from the remaining first semiconductor laser elements are moved in opposite directions along one side of the incident surface of the integrator illumination system. The light source device according to item 2, characterized by the features described above. [Matter 4] The aforementioned corrective optical system is A first prism is positioned between the first laser module and the incident surface to deflect the laser beam emitted from some of the first semiconductor laser elements, The system comprises a second prism positioned between the first laser module and the incident surface, which deflects the laser beam emitted from the remaining first semiconductor laser elements in a direction different from that of the first prism, A light source device as described in item 3, characterized by the features described herein. [Matter 5] A first lens is positioned between the first laser module and the incident surface, and focuses the laser beam emitted from a portion of the first semiconductor laser elements to a first position on the incident surface. The system includes a second lens positioned between the first laser module and the incident surface, which focuses the laser beam emitted from the remaining first semiconductor laser elements to a second position different from the first position on the incident surface. A light source device as described in item 3, characterized by the features described herein. [Matter 6] The aforementioned corrective optical system is The device has fixing means for tilting and fixing the portion of the first semiconductor laser elements and the remaining first semiconductor laser elements so that the emission direction of the portion of the first semiconductor laser elements and the emission direction of the remaining first semiconductor laser elements are different. A light source device as described in item 3, characterized by the features described herein. [Matter 7] The laser light of the first wavelength is blue or green, and the laser light of the second wavelength is red. A light source device according to any one of items 1 to 6, characterized by the features described herein. [Matter 8] A light source device as described in any one of items 1 to 7, A reflective optical modulator and A transfer optical system for transferring laser light emitted from the output surface of the integrator illumination system to the reflective optical modulation element, The system comprises a projection lens that projects the image light output by the reflective optical modulation element, A projection-type display device characterized by the following features. [Explanation of symbols]

[0087] 11A, 11B... Semiconductor laser / 12... Light-emitting part / 100B... Blue light source / 100G... Green light source / 100R... Red light source / 101... Collimating lens / 103... Focusing lens / 103L, 103R... Focusing lens / 104... Diffuser plate / 105... Rod / 190... Projection screen / 201... Front transfer lens / 202... Rear transfer lens / 210B... Deflector for B / 210G... Deflector for G / 210R... Deflector for R / 220... Photosynthesis section / 221, 222... Dichroic mirror / 330... Optical path conversion mirror / 340... Reflective optical modulator / 350... TIR prism / 360... Projection lens / 1000, 2000... Projection display device / EXP... Output surface / INP... Incident surface / LML, LMR... Laser module / PAL, PAR... Prism array / WPL, WPR... Wedge prism

Claims

1. A first laser module having multiple first semiconductor laser elements, A second laser module having multiple second semiconductor laser elements, An integrator illumination system that superimposes multiple laser beams incident on the incident surface and emits them from the exit surface, Equipped with a corrective optical system, Each of the plurality of first semiconductor laser elements is equipped with one light-emitting section and emits laser light of a first wavelength. Each of the plurality of second semiconductor laser elements is equipped with two light-emitting units and emits laser light of a second wavelength. The intensity distribution of the laser beam incident on the incident surface of the integrator illumination system from the second laser module has two peaks aligned along one side of the incident surface, and at the position of the peaks, the laser beam has a spot shape whose longitudinal direction is aligned along the one side of the incident surface. The correction optical system is an optical system that approximates the intensity distribution of the laser beam incident on the incident surface of the integrator illumination system from the first laser module to the intensity distribution of the laser beam incident on the incident surface of the integrator illumination system from the second laser module. A light source device characterized by the following features.

2. In the first laser module, the longitudinal directions of the light-emitting portions of each of the plurality of first semiconductor laser elements are oriented in the same direction. In the second laser module, the longitudinal directions of the light-emitting portions of each of the plurality of second semiconductor laser elements are oriented in the same direction. The aforementioned corrective optical system is The optical path of the laser beam emitted from the first laser module is corrected so that the intensity distribution of the laser beam incident on the incident surface from the first laser module has two peaks aligned along one side of the incident surface. The light source device according to feature 1.

3. The aforementioned corrective optical system is The irradiation position of the laser beam emitted from some of the multiple first semiconductor laser elements and the irradiation position of the laser beam emitted from the remaining first semiconductor laser elements are moved in opposite directions along one side of the incident surface of the integrator illumination system. The light source device according to claim 2.

4. The aforementioned corrective optical system is A first prism is positioned between the first laser module and the incident surface to deflect the laser beam emitted from some of the first semiconductor laser elements, The system comprises a second prism positioned between the first laser module and the incident surface, which deflects the laser beam emitted from the remaining first semiconductor laser elements in a direction different from that of the first prism. The light source device according to feature 3.

5. A first lens is positioned between the first laser module and the incident surface, and focuses the laser beam emitted from a portion of the first semiconductor laser elements to a first position on the incident surface. The system includes a second lens positioned between the first laser module and the incident surface, which focuses the laser beam emitted from the remaining first semiconductor laser elements to a second position different from the first position on the incident surface. The light source device according to feature 3.

6. The aforementioned corrective optical system is The device has fixing means for tilting and fixing the portion of the first semiconductor laser elements and the remaining first semiconductor laser elements so that the emission direction of the portion of the first semiconductor laser elements and the emission direction of the remaining first semiconductor laser elements are different. The light source device according to feature 3.

7. The first wavelength laser light is blue or green, and the second wavelength laser light is red. The light source device according to feature 1.

8. A light source device according to any one of claims 1 to 7, A reflective optical modulator and A transfer optical system for transferring laser light emitted from the output surface of the integrator illumination system to the reflective optical modulation element, The system comprises a projection lens that projects the image light output by the reflective optical modulation element, A projection-type display device characterized by the following features.

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