Projector

Abstract

To provide a projector with reduced speckle noise.SOLUTION: A projector includes: a first laser light emitting element that emits first light; a second laser light emitting element that emits second light having the same peak wavelength as the first light; a diffusion member on which the first light and the second light are incident; a superimposition optical system on which the light emitted from the diffusion member is incident; a light modulation device that modulates the light incident from the superimposition optical system in accordance with image information; and a projection optical device that projects the light modulated by the light modulation device. The first laser light emitting element and the second laser light emitting element have oscillation states different from each other.SELECTED DRAWING: Figure 2B

Description

[Technical Field]

[0001] The present invention relates to a projector. [Background technology]

[0002] To improve the performance of projectors, projectors have been proposed that include an illumination device using a laser light source, which is a light source with a wide color gamut and high efficiency. Patent Document 1 listed below discloses an illumination device that includes a blue laser light source, a green laser light source, a red laser light source, multiple dichroic mirrors that combine the color lights emitted from the laser light sources, and a diffusion plate that diffuses the combined light combined by the multiple dichroic mirrors. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-40177 Summary of the Invention [Problem to be solved by the invention]

[0004] In the illumination device of Patent Document 1, the laser light source for each color has a configuration in which multiple semiconductor lasers are arranged two-dimensionally. However, since the light from each semiconductor laser arranged two-dimensionally in each laser light source interferes with each other, there was a problem in that it was difficult to sufficiently remove speckle noise when using a diffusion plate to diffuse the combined light. [Means for solving the problem]

[0005] In order to solve the above problem, one embodiment of the projector of the present invention comprises a first laser light-emitting element that emits a first light, a second laser light-emitting element that emits a second light having the same peak wavelength as the first light, a diffusion member onto which the first light and the second light are incident, a superimposing optical system onto which the light emitted from the diffusion member is incident, an optical modulation device that modulates the light incident from the superimposing optical system according to image information, and a projection optical device that projects the light modulated by the optical modulation device, wherein the first laser light-emitting element and the second laser light-emitting element have different oscillation states. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a projector 1 according to an embodiment. [Figure 2A] FIG. 2A is a schematic diagram of the illumination device 2. As shown in FIG. [Figure 2B] FIG. 2B is an enlarged view showing the main configuration of the lighting device 2. As shown in FIG. [Figure 3A] FIG. 10 is a diagram showing the duty ratio of the light emitting element of the first red light source package. [Figure 3B] FIG. 10 is a diagram showing the duty ratio of the light emitting element of the second red light source package. [Figure 3C] FIG. 10 is a diagram showing the duty ratio of the light emitting element of the third red light source package. [Figure 3D] FIG. 10 is a diagram showing the duty ratio of the light emitting element of the fourth red light source package. [Figure 4] FIG. 10 is a diagram showing the configuration of a main part of a red light source unit according to a third embodiment. [Figure 5] FIG. 10 is a diagram showing a schematic configuration of an illumination device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each drawing, the scale of the dimensions of some components may be changed to make each component easier to see.

[0008] [First embodiment] A projector according to a first embodiment of the present invention will be described. FIG. 1 is a schematic diagram showing the configuration of a projector 1 according to this embodiment. As shown in FIG. 1, the projector 1 according to this embodiment is a projection-type image display device that displays an image on a screen SCR. The projector 1 includes an illumination device 2, a color separation optical system 3, light modulation devices 4R, 4G, and 4B, a color synthesis optical system 5, and a projection optical device 6. The projector 1 is a three-plate projector having three light modulation devices.

[0009] The illumination device 2 emits white light WL toward the color separation optical system 3. The white light WL is illumination light in the projector 1, and includes red light RL, green light GL, and blue light BL. The configuration of the illumination device 2 will be described later.

[0010] The color separation optical system 3 separates the white light WL into red light RL, green light GL, and blue light BL. The color separation optical system 3 includes, for example, a first dichroic mirror 11, a second dichroic mirror 12, a first reflecting mirror 13, a second reflecting mirror 14, a third reflecting mirror 15, a first relay lens 16, and a second relay lens 17.

[0011] The first dichroic mirror 11 is disposed on the optical path of the white light WL emitted from the lighting device 2, and separates the incident white light WL into red light RL, green light GL, and blue light BL. The first dichroic mirror 11 transmits the red light RL and reflects the green light GL and blue light BL. The second dichroic mirror 12 is disposed on the common optical path of the green light GL and blue light BL emitted from the first dichroic mirror 11, and separates the green light GL from the blue light BL. The second dichroic mirror 12 transmits the blue light BL and reflects the green light GL.

[0012] The first reflecting mirror 13 reflects the red light RL toward the light modulation device 4R. The second reflecting mirror 14 and the third reflecting mirror 15 guide the blue light BL to the light modulation device 4B. The green light GL is reflected from the second dichroic mirror 12 toward the light modulation device 4G. The red light RL, green light GL, and blue light BL contained in the white light WL correspond to the light emitted from the illumination device 2.

[0013] The first relay lens 16 is disposed on the optical path of the blue light BL between the second dichroic mirror 12 and the second reflecting mirror 14. The second relay lens 17 is disposed on the optical path of the blue light BL between the second reflecting mirror 14 and the third reflecting mirror 15. By disposing the first relay lens 16 and the second relay lens 17 as described above, optical loss of the blue light BL is compensated for. The optical loss of the blue light BL occurs because the optical path length of the blue light BL from the first dichroic mirror 11 to the optical modulation device 4B is longer than the optical path length of the red light RL from the first dichroic mirror 11 to the optical modulation device 4R and the optical path length of the green light GL from the first dichroic mirror 11 to the optical modulation device 4G.

[0014] The light modulation device 4R is disposed on the optical path of the red light RL reflected by the first reflecting mirror 13 and emitted from the first reflecting mirror 13. The light modulation device 4R modulates the incident red light RL in accordance with image information input from an image input device (not shown), forms red image light, and emits the red image light. The light modulation device 4G is disposed on the optical path of the green light GL reflected by the second dichroic mirror 12 and emitted from the second dichroic mirror 12. The light modulation device 4G modulates the incident green light GL in accordance with image information input from an image input device (not shown), forms green image light, and emits the green image light. The light modulation device 4B is disposed on the optical path of the blue light BL reflected by the third reflecting mirror 15 and emitted from the third reflecting mirror 15. The light modulation device 4B modulates the incident blue light BL in accordance with image information input from an image input device (not shown), forms blue image light, and emits the blue image light. The image input device may be, for example, a personal computer or a portable terminal device.

[0015] Each of the light modulation devices 4R, 4G, and 4B uses, for example, a transmissive liquid crystal panel. Polarizing plates (not shown) are arranged on the incident and exit sides of the liquid crystal panel. A field lens 10R is arranged on the optical path of the red light RL between the first reflecting mirror 13 and the light modulation device 4R. A field lens 10G is arranged on the optical path of the green light GL between the second dichroic mirror 12 and the light modulation device 4G. A field lens 10B is arranged on the optical path of the blue light BL between the third reflecting mirror 15 and the light modulation device 4B.

[0016] The color combining optical system 5 is disposed across the optical path of the red image light emitted from the light modulation device 4R, the optical path of the green image light emitted from the light modulation device 4G, and the optical path of the blue image light emitted from the light modulation device 4B. When viewed from the top or side as shown in FIG. 1 , the combining position of the colored lights in the color combining optical system 5 overlaps with the intersection of the optical paths of the red image light, the green image light, and the blue image light. In the color combining optical system 5, the red image light, the green image light, and the blue image light are combined together to form colored image light. The color combining optical system 5 emits colored image light. For example, a cross dichroic prism is used for the color combining optical system 5.

[0017] The projection optical device 6 is disposed on the optical path of the color image light emitted from the color combining optical system 5. The color image light emitted from the color combining optical system 5 corresponds to light modulated by the light modulation devices 4R, 4G, and 4B. The projection optical device 6 enlarges and projects the color image light emitted from the color combining optical system 5 and incident thereon onto the screen SCR. The color image light enlarged and projected from the projection optical device 6 is displayed as a color image on the display surface of the screen SCR opposite the emission surface of the projection optical device 6.

[0018] The projection optical device 6 is configured, for example, by a plurality of optical lenses, but may also be configured by a single optical lens. Optical lenses include various lenses such as plano-convex lenses, biconvex lenses, meniscus lenses, aspherical lenses, rod lenses, and free-form lenses.

[0019] Next, a description will be given of the configuration of the lighting device 2. Fig. 2A is a schematic configuration diagram of the lighting device 2. Fig. 2B is an enlarged view showing the configuration of the main part of the lighting device 2. As shown in FIG. 2A, the illumination device 2 includes a red light source unit 21 that emits red illumination light LR, a green light source unit 22 that emits green illumination light LG, a blue light source unit 23 that emits blue illumination light LB, a light combining unit 24, a focusing optical system 25, a diffusion device 26, a collimating element 27, and a superimposing optical system 30.

[0020] In the following description, the arrangement of each component may be described using an XYZ coordinate system. In this specification, the axis parallel to the optical axis AX1 of the green illumination light LG emitted from the green light source unit 22 is defined as the X axis. The axis parallel to the optical axis AX2 of each of the illumination lights LR and LB emitted from the red light source unit 21 and the blue light source unit 23 and perpendicular to the X axis is defined as the Y axis. The axis perpendicular to the X axis and the Y axis is defined as the Z axis.

[0021] As shown in FIG. 2B, the red light source unit 21 has four light source packages arranged in one direction: a first red light source package (first light source package) 211, a second red light source package (second light source package) 212, a third red light source package 213, and a fourth red light source package 214.

[0022] First red light source package 211 has a plurality of first red laser light emitting elements (first laser light emitting elements) 40a. First red laser light emitting elements 40a are configured with semiconductor lasers that emit red light rays (first light) R1. Red light rays R1 are red laser light having a red wavelength band of 585 to 720 nm, for example. First red light source package 211 has a multi-emitter package structure in which substrate 41 supporting base member 44, on which four first red laser light emitting elements 40a are mounted along the Z-axis direction, is sealed with cover glass 43. Note that the number of first red laser light emitting elements 40a constituting first red light source package 211 is not limited to four.

[0023] In first red light source package 211, cover glass 43 is attached to substrate 41 via frame 42. Multiple collimator lenses 43a are integrally provided on cover glass 43. Collimator lenses 43a are configured as convex lenses. Collimator lenses 43a collimate red light beams R1 emitted from corresponding first red laser light emitting elements 40a. Collimator lenses 43a may be separate from cover glass 43. Hereinafter, multiple red light beams R1 emitted from multiple collimator lenses 43a will be collectively referred to as red light beam LR1. Based on this configuration, first red light source package 211 emits a red light beam LR1 consisting of multiple red light rays R1 as parallel light. Because first red light source package 211 has a multi-emitter package structure, it is possible to emit a high-intensity red light beam LR1 while miniaturizing the device configuration.

[0024] Second red light source package 212 has a plurality of second red laser light-emitting elements (second laser light-emitting elements) 40b arranged in an array. Second red laser light-emitting elements 40b are composed of semiconductor lasers that emit red light (second light) R2 having the same peak wavelength as red light R1. Here, "having the same peak wavelength as red light R1" does not necessarily mean that the peak wavelengths of red light R1 and R2 are completely the same, but also means that there is a difference of ±2 nm, more preferably ±1 nm.

[0025] Like the first red light source package 211, the second red light source package 212 has a multi-emitter package structure. Therefore, the second red light source package 212 is configured by sealing a substrate 41, on which four second red laser light emitting elements 40b are mounted along the Z-axis direction, with a cover glass 43. Based on this configuration, the second red light source package 212 emits a red light beam LR2 consisting of multiple red light rays R2 as parallel light. Because the second red light source package 212 has a multi-emitter package structure, it is possible to emit a high-intensity red light beam LR1 while miniaturizing the device configuration.

[0026] Third red light source package 213 has a plurality of third red laser light emitting elements 40c arranged in an array. Third red laser light emitting element 40c is composed of a semiconductor laser that emits red light R3 having the same peak wavelength as red light R1 and R2. Similar to the first red light source package 211 or the second red light source package 212, the third red light source package 213 has a multi-emitter package structure. Therefore, the third red light source package 213 is configured by sealing a substrate 41, on which four third red laser light emitting elements 40c are mounted along the Z-axis direction, with a cover glass 43. Based on this configuration, the third red light source package 213 emits a red light beam LR3 consisting of multiple red light rays R3 as parallel light. Because the third red light source package 213 has a multi-emitter package structure, it is possible to emit a high-intensity red light beam LR3 while miniaturizing the device configuration.

[0027] Fourth red light source package 214 has a plurality of fourth red laser light emitting elements 40d arranged in an array. Fourth red laser light emitting element 40d is composed of a semiconductor laser that emits red light R4 having the same peak wavelength as red light R1, R2, and R3. The fourth red light source package 214 has a multi-emitter package structure, similar to the first red light source package 211, the second red light source package 212, or the third red light source package 213. For this reason, the fourth red light source package 214 is configured by sealing a substrate 41, on which four fourth red laser light emitting elements 40d are mounted along the Z-axis direction, with a cover glass 43. Based on this configuration, the fourth red light source package 214 emits a red light beam LR4 consisting of multiple red light rays R4 as parallel light. Because the fourth red light source package 214 has a multi-emitter package structure, it is possible to emit a high-intensity red light beam LR4 while miniaturizing the device configuration.

[0028] In this way, red light source unit 21 emits red illumination light LR including red light beams LR1 to LR4 emitted from light source packages 211 to 214 along optical axis AX1, and makes it incident on light combining unit 24 located on the -Y side.

[0029] The oscillation states of the light source packages 211 to 214 of the red light source unit 21 are different from one another. In this embodiment, the light source packages 211 to 214 have different drive frequencies for driving their respective light emitting elements. Here, the drive frequency refers to the frequency at which a predetermined drive current is applied in pulses to the light emitting elements.

[0030] In the red light source unit 21, for example, the first drive frequency F1 of the first red laser light emitting element 40a of the first red light source package 211 is set to 120 Hz, the second drive frequency F2 of the second red laser light emitting element 40b of the second red light source package 212 is set to 160 Hz, the third drive frequency F3 of the third red laser light emitting element 40c of the third red light source package 213 is set to 180 Hz, and the fourth drive frequency F4 of the fourth red laser light emitting element 40d of the fourth red light source package 214 is set to 200 Hz. The drive frequencies of the light source packages 211 to 214 are not integer multiples of each other. The drive frequencies F1 to F4 are input to the light emitting elements 40a to 40d of the light source packages 211 to 214 via the control device CONT.

[0031] That is, in this embodiment, the first drive frequency F1 of the first red laser light emitting element 40a of the first red light source package 211 is different from the second drive frequency F2 of the second red laser light emitting element 40b of the second red light source package 212. The first drive frequency F1 and the second drive frequency F2 are not in an integer multiple relationship with each other.

[0032] Green light source section 22 has four light source packages, ie, first green light source package 221, second green light source package 222, third green light source package 223, and fourth green light source package 224, arranged in one direction.

[0033] First green light source package 221 has a plurality of first green laser light emitting elements (third laser light emitting elements) 50a. First green laser light emitting elements 50a are configured with semiconductor lasers that emit green light rays (third light) G1 in a wavelength band different from that of red light rays R1. Green light rays G1 are green laser light having a wavelength band of, for example, 495 nm to 585 nm. First green light source package 221 has a multi-emitter package structure in which substrate 51 supporting base member 54, on which four first green laser light emitting elements 50a are mounted along the Z-axis direction, is sealed with cover glass 53. Note that the number of first green laser light emitting elements 50a constituting first green light source package 221 is not limited to four.

[0034] In first green light source package 221, cover glass 53 is attached to substrate 51 via frame 52. Multiple collimator lenses 53a are integrally provided on cover glass 53. Collimator lenses 53a are configured as convex lenses. Collimator lenses 53a collimate green light beams G1 emitted from corresponding first green laser light emitting elements 50a. Collimator lenses 53a may be separate from cover glass 53. Hereinafter, multiple green light beams G1 emitted from multiple collimator lenses 53a will be collectively referred to as green light beam LG1. Based on this configuration, first green light source package 221 emits green light beam LG1 consisting of multiple green light rays G1 as parallel light. Because first green light source package 221 has a multi-emitter package structure, it is possible to emit high-intensity green light beam LG1 while miniaturizing the device configuration.

[0035] Second green light source package 222 has a plurality of second green laser light-emitting elements (fourth laser light-emitting elements) 50b arranged in an array. Second green laser light-emitting element 50b is composed of a semiconductor laser that emits green light (fourth light) G2 having the same peak wavelength as green light G1. Here, "having the same peak wavelength as green light G1" does not necessarily mean that the peak wavelengths of green light G1 and G2 are completely the same, but also means that there is a difference of ±2 nm, more preferably ±1 nm.

[0036] Like first green light source package 221, second green light source package 222 has a multi-emitter package structure. Therefore, second green light source package 222 is configured by sealing substrate 51, on which four second green laser light emitting elements 50b are mounted along the Z-axis direction, with cover glass 53. Based on this configuration, second green light source package 222 emits green light beam LG2 consisting of multiple green light rays G2 as parallel light. Because second green light source package 222 has a multi-emitter package structure, it is possible to emit high-intensity green light beam LG2 while miniaturizing the device configuration.

[0037] Third green light source package 223 has a plurality of third green laser light emitting elements 50c arranged in an array. Third green laser light emitting element 50c is composed of a semiconductor laser that emits green light G3 having the same peak wavelength as green light G1 and G2. Similar to first green light source package 221 or second green light source package 222, third green light source package 223 has a multi-emitter package structure. Therefore, third green light source package 223 is configured by sealing substrate 51, on which four third green laser light emitting elements 50c are mounted along the Z-axis direction, with cover glass 53. Based on this configuration, third green light source package 223 emits green light beam LG3 consisting of multiple green light rays G3 as parallel light. Because third green light source package 223 has a multi-emitter package structure, it is possible to emit a high-intensity green light beam LG3 while miniaturizing the device configuration.

[0038] Fourth green light source package 224 has a plurality of fourth green laser light emitting elements 50d arranged in an array. Fourth green laser light emitting element 50d is composed of a semiconductor laser that emits green light G4 having the same peak wavelength as green light G1, G2, and G3. Fourth green light source package 224 has a multi-emitter package structure, similar to first green light source package 221, second green light source package 222, or third green light source package 223. For this reason, fourth green light source package 224 is configured by sealing substrate 51, on which four fourth green laser light emitting elements 50d are mounted along the Z-axis direction, with cover glass 53. Based on this configuration, fourth green light source package 224 emits green light beam LG4 consisting of multiple green light rays G4 as parallel light. Because fourth green light source package 224 has a multi-emitter package structure, it is possible to emit a high-intensity green light beam LG4 while miniaturizing the device configuration.

[0039] In this way, green light source unit 22 emits green illumination light LG including green light beams LG1 to LG4 emitted from light source packages 221 to 224 along optical axis AX2, and makes it incident on light combining unit 24 located on the +X side.

[0040] Similar to the red light source unit 21, the light source packages 221-224 of the green light source unit 22 have mutually different oscillation states. That is, in this embodiment, the first green laser light emitting element 50a and the second green laser light emitting element 50b have mutually different oscillation states. In this embodiment, the light source packages 221-224 have different drive frequencies for driving the light emitting elements 50a-50d. Note that the drive frequencies of the light source packages 221-224 are not integer multiples of each other.

[0041] Blue light source unit 23 has four light source packages, namely, first blue light source package 231, second blue light source package 232, third blue light source package 233, and fourth blue light source package 234, arranged in one direction.

[0042] First blue light source package 231 has a plurality of first blue laser light-emitting elements (fifth laser light-emitting elements) 60a. First blue laser light-emitting elements 60a are configured with semiconductor lasers that emit blue light (fifth light) B1 in a wavelength band different from the red light R1 and green light G1. Blue light B1 is, for example, blue laser light in a wavelength band of 380 nm to 495 nm. First blue light source package 231 has a multi-emitter package structure in which substrate 61 supporting base member 64 on which four first blue laser light emitting elements 60a are mounted along the Z-axis direction is sealed with cover glass 63. Note that the number of first blue laser light emitting elements 60a constituting first blue light source package 231 is not limited to four.

[0043] In first blue light source package 231, cover glass 63 is attached to substrate 61 via frame 62. Multiple collimator lenses 63a are integrally provided on cover glass 63. Collimator lenses 63a are configured as convex lenses. Collimator lenses 63a collimate blue light beams B1 emitted from corresponding first blue laser light emitting elements 60a. Collimator lenses 63a may be separate from cover glass 63. Hereinafter, multiple blue light beams B1 emitted from multiple collimator lenses 63a will be collectively referred to as blue light beam LB1. Based on this configuration, first blue light source package 231 emits a blue light beam LB1 consisting of a plurality of blue light rays B1 as parallel light.

[0044] Second blue light source package 232 has a plurality of second blue laser light-emitting elements (sixth laser light-emitting elements) 60b arranged in an array. Second blue laser light-emitting element 60b is composed of a semiconductor laser that emits blue light (sixth light) B2 having the same peak wavelength as blue light B1. Here, "having the same peak wavelength as blue light B1" does not necessarily mean that the peak wavelengths of blue light B1 and B2 completely match, but also means that there is a difference of ±2 nm, more preferably ±1 nm.

[0045] Second blue light source package 232 has a multi-emitter package structure, similar to first blue light source package 231. Therefore, second blue light source package 232 is configured by sealing substrate 61, on which four second blue laser light emitting elements 60b are mounted along the Z-axis direction, with cover glass 63. Based on this configuration, second blue light source package 232 emits blue light beam LB2 consisting of multiple blue light rays B2 as parallel light.

[0046] Third blue light source package 233 has a plurality of third blue laser light emitting elements 60c arranged in an array. Third blue laser light emitting element 60c is composed of a semiconductor laser that emits blue light B3 having the same peak wavelength as blue light B1 and B2. Similar to first blue light source package 231 or second blue light source package 232, third blue light source package 233 has a multi-emitter package structure. Therefore, third blue light source package 233 is configured by sealing substrate 61, on which four third blue laser light emitting elements 60c are mounted along the Z-axis direction, with cover glass 63. Based on this configuration, third blue light source package 233 emits blue light beam LB3 consisting of multiple blue light rays B3 as parallel light.

[0047] Fourth blue light source package 234 has a plurality of fourth blue laser light emitting elements 60d arranged in an array. Fourth blue laser light emitting element 60d is composed of a semiconductor laser that emits blue light B4, which has the same peak wavelength as blue light B1, B2, and B3. Fourth blue light source package 234 has a multi-emitter package structure, similar to first blue light source package 231, second blue light source package 232, or third blue light source package 233. For this reason, fourth blue light source package 234 is configured by sealing substrate 61, on which four fourth blue laser light emitting elements 60d are mounted along the Z-axis direction, with cover glass 63. Based on this configuration, fourth blue light source package 234 emits blue light beam LB4 consisting of multiple blue light rays B4 as parallel light.

[0048] In this way, blue light source unit 23 emits blue illumination light LB including blue light beams LB1 to LB4 emitted from light source packages 231 to 234 along optical axis AX1, and makes it incident on light combining unit 24 located on the +Y side.

[0049] Similar to the red light source unit 21 and the green light source unit 22, the oscillation states of the light source packages 231-234 of the blue light source unit 23 are different from one another. That is, in this embodiment, the first blue laser light emitting element 60a and the second blue laser light emitting element 60b are different from one another in oscillation states. In this embodiment, the light source packages 231-234 have different drive frequencies for driving the light emitting elements 60a-60d. Note that the drive frequencies of the light source packages 231-234 are not integer multiples of one another.

[0050] Light combining unit 24 is disposed across the optical path of red illumination light LR emitted from red light source unit 21, the optical path of green illumination light LG emitted from green light source unit 22, and the optical path of blue illumination light LB emitted from blue light source unit 23. When viewed from the top or side as shown in Fig. 2A, the position where the colored lights are combined in light combining unit 24 overlaps with the intersection of the optical path of red illumination light LR, the optical path of green illumination light LG, and the optical path of blue illumination light LB, i.e., the intersection of optical axis AX1 and optical axis AX2.

[0051] In the light combining unit 24, the incident red illumination light LR, green illumination light LG, and blue illumination light LB are combined together to generate white light WL. The white light WL corresponds to the combined light. The light combining unit 24 emits the white light WL along an optical axis AX2. The optical axis AX2 of the white light WL is collinear with the optical axis AX2 of the green illumination light LG. The optical axis AX2 of the white light WL is an axis that extends from the optical axis AX2 of the green illumination light LG toward the light combining unit 24 so as to pass through the combination position of the colored lights in the light combining unit 24, and further extends in the opposite direction from the green light source unit 22 relative to the light combining unit 24.

[0052] The light combining unit 24 uses, for example, a cross dichroic prism 240. The cross dichroic prism 240 has a first dichroic mirror 241 and a second dichroic mirror 242. In a plan view or a side view in which the optical axes AX1 and AX2 are perpendicular to each other, the reflective surfaces of the first dichroic mirror 241 and the second dichroic mirror 242 are inclined with respect to the optical axes AX1 and AX2. In a plan view or a side view in which the optical axes AX1 and AX2 are perpendicular to each other, the reflective surfaces of the first dichroic mirror 241 and the second dichroic mirror 242 form angles of 45° with the optical axes AX1 and AX2. In a plan view or a side view in which the optical axes AX1 and AX2 are perpendicular to each other, the reflective surfaces of the first dichroic mirror 241 and the second dichroic mirror 242 are perpendicular to each other.

[0053] The first dichroic mirror 241 reflects the blue illumination light LB and transmits the green illumination light LG and the red illumination light LR. The second dichroic mirror 242 reflects the red illumination light LR and transmits the blue illumination light LB and the green illumination light LG. The red illumination light LR emitted from the red light source unit 21 is incident on the second dichroic mirror 242 along the optical axis AX1, reflected by the second dichroic mirror 242, and emitted along the optical axis AX2 to the side opposite the green light source unit 22 and transmitted through the first dichroic mirror 241. The green illumination light LG emitted from the green light source unit 22 is incident on the first dichroic mirror 241 along the optical axis AX2, travels straight, and transmits through the first dichroic mirror 241 and the second dichroic mirror 242. The blue illumination light LB emitted from the blue light source unit 23 enters the first dichroic mirror 241 along the optical axis AX1, is reflected by the first dichroic mirror 241, and is emitted along the optical axis AX2 to the opposite side from the green light source unit 22, and passes through the second dichroic mirror 242.

[0054] As described above, the red illumination light LR, the green illumination light LG, and the blue illumination light LB emitted from the first dichroic mirror 241 and the second dichroic mirror 242 are combined to generate white light WL. The white light WL is emitted along the optical axis AX2 from the side of the cross dichroic prism 240 opposite to the side facing the green light source unit 22.

[0055] The focusing optical system 25 is disposed on the optical path of the white light WL between the light combining unit 24 and the diffusing device 26. The focusing optical system 25 focuses the white light WL, which has been emitted from the light combining unit 24 and has been collimated, toward the diffusing member 28 of the diffusing device 26. The center of the diffusing member 28 in a direction perpendicular to the optical axis AX2 substantially overlaps with the optical axis AX2. The focusing optical system 25 is, for example, a biconvex lens, but may be an optical element having a focusing function other than a biconvex lens, may be a plano-convex lens, or may be composed of multiple optical lenses.

[0056] The diffusion device 26 is disposed on the optical path of the white light WL emitted from the focusing optical system 25. The diffusion device 26 diffuses and emits the incident white light WL while being focused by the focusing optical system 25. The diffusion device 26 is, for example, a reflective diffusion device, and diffuses and reflects the incident white light WL.

[0057] Diffusion device 26 has diffusion member 28 made of a diffusion plate, and drive device 29. Diffusion member 28 has incident surface 28a onto which white light WL collected by collecting optical system 25 is irradiated, and a back surface 28b opposite incident surface 28a. Diffusion member 28 is disposed with incident surface 28a facing collecting optical system 25. In a plan view or side view in which optical axes AX1 and AX2 are perpendicular to each other, the angle formed by incident surface 28a and optical axis AX2 is 45°.

[0058] The diffusion member 28 is attached to the drive device 29 in a state in which it can rotate about a rotation axis OX1. The drive device 29 rotates the diffusion member 28 about the rotation axis OX1. The drive device 29 is, for example, a motor. Note that the drive device 29 is not limited to a motor and may be any device that can rotate the diffusion member 28 as described above.

[0059] In the diffusion device 26, a focused spot SP of the white light WL is formed on the incident surface 28a of the diffusion member 28. The incident surface 28a has a scattering surface formed of an uneven structure that scatters the white light WL. The white light WL diffused by the diffusion member 28 is emitted as diffused light from the focused spot SP along the illumination optical axis AX and enters the collimating element 27. The illumination optical axis AX passes through the center of the illumination area of ​​the focused spot SP on the incident surface 28a of the diffusion member 28 and is parallel to the optical axis AX1.

[0060] The collimating element 27 collimates the divergent and diffused white light WL emitted from the diffusing member 28. The center of the collimating element 27 in a direction perpendicular to the illumination optical axis AX substantially overlaps with the illumination optical axis AX. The collimating element 27 is, for example, a biconvex lens, but may be an optical element other than a biconvex lens that has a light-collecting function, a plano-convex lens, or may be composed of multiple optical lenses. Note that when the collimating element 27 is composed of a single optical lens, the accuracy of collimation can be further improved by using an aspherical lens.

[0061] The white light WL diffused by the diffusing member 28 of the diffusion device 26 enters the superimposing optical system 30. The superimposing optical system 30 has a multi-lens array 31 and a superimposing lens 32. The superimposing optical system 30 homogenizes the illuminance distribution of the white light WL emitted from the collimating element 27 in the image forming regions of the light modulation devices 4R, 4G, and 4B arranged downstream.

[0062] The multilens array 31 is disposed on the optical path of the white light WL emitted from the collimating element 27 and collimated. The multilens array 31 is, for example, a double-sided multilens array. The double-sided multilens includes a plurality of first microlenses 33 for dividing the white light WL emitted from the collimating element 27 into a plurality of small beams. The first microlenses 33 are arranged adjacent to one another in a matrix along a plane perpendicular to the illumination optical axis AX. The first microlenses 33 are, for example, plano-convex lenses that are convex toward the incident side. The multilens array 31 has a first multilens surface 31a provided on the incident side in accordance with the shape of the plano-convex lens that constitutes the first microlenses 33. The double-sided multilens includes a plurality of second microlenses 34, the same number as the plurality of first microlenses 33, on a plane perpendicular to the illumination optical axis AX. The second microlenses 34 are arranged adjacent to one another in a matrix along a plane perpendicular to the illumination optical axis AX and overlap with each first microlens 33. The second microlenses 34 are, for example, plano-convex lenses that are convex on the exit side. The exit-side flat surface of each of the second microlenses 34 is common to the incident-side flat surface of each of the first microlenses 33. The multi-lens array 31 has a second multi-lens surface 31b that is provided on the exit side along the shape of the plano-convex lenses that form the second microlenses 34.

[0063] The superimposing lens 32 collects each of the multiple small beams of white light WL emitted from the multi-lens array 31, and superimposes the collected beams on each other in the image forming area of ​​each of the light modulation devices 4R, 4G, and 4B or in the vicinity of the image forming area in cooperation with the multiple second microlenses 34 of the multi-lens array 31. The superimposing lens 32 is, for example, a plano-convex lens, but may also be an optical element having a light collecting function other than a plano-convex lens, may be a biconvex lens, or may be composed of multiple optical lenses.

[0064] Here, since the color illumination lights LR, LG, and LB contained in the white light WL are coherent lights, there is a risk of optical interference. The illumination device 2 of this embodiment can reduce speckle noise caused by the white light WL by diffusing the white light WL using the diffusing member 28 of the diffusing device 26.

[0065] The projector 1 of this embodiment further enhances the speckle noise reduction effect of the diffusion member 28 by making the oscillation states of the light-emitting elements of the red light source section 21, the green light source section 22, and the blue light source section 23 different from one another.

[0066] The projector 1 of this embodiment is configured to suppress mutual interference between the red light beams LR1 to LR4 emitted from the light source packages 211 to 214 by varying the drive frequencies of the light emitting elements 40a to 40d of the light source packages 211 to 214 in the red light source section 21. In this case, the drive frequencies of the light source packages 211 to 214 are not integer multiples of each other, so that one drive frequency is not included in the other drive frequencies. This makes it possible to more effectively suppress mutual interference between the red light beams LR1 to LR4.

[0067] Furthermore, the projector 1 of this embodiment is configured to suppress mutual interference between the green light beams LG1 to LG4 emitted from the light source packages 221 to 224 by varying the drive frequencies of the light emitting elements 50a to 50d of the light source packages 221 to 224 in the green light source section 22. In this case, the drive frequencies of the light source packages 221 to 224 are not integer multiples of each other, so that mutual interference between the green light beams LG1 to LG4 can be effectively suppressed.

[0068] Furthermore, the projector 1 of this embodiment is configured to suppress mutual interference between the blue light beams LB1 to LB4 emitted from the light source packages 231 to 234 by varying the drive frequencies of the light emitting elements 60a to 60d of the light source packages 231 to 234 in the blue light source section 23. In this case, the drive frequencies of the light source packages 231 to 234 are not integer multiples of each other, so that mutual interference between the blue light beams LB1 to LB4 can be effectively suppressed.

[0069] In this way, in the projector 1 of this embodiment, the red light beams LR1 to LR4 contained in the red illumination light LR, the green light beams LG1 to LG4 contained in the green illumination light LG, and the blue light beams LB1 to LB4 contained in the blue illumination light LB can each be superimposed onto the screen, which is the projection surface, to form multiple speckle patterns that do not interfere with each other. Therefore, according to the projector 1 of this embodiment, it is possible to display a high-quality image with reduced speckle noise in the illumination lights of the respective colors LR, LG, and LB.

[0070] [Second embodiment] Next, a second embodiment of the present invention will be described. The projector 1 of the first embodiment was exemplified as a case in which the driving frequencies of the light-emitting elements of the red light source section 21, the green light source section 22, and the blue light source section 23 are made different to make the oscillation states of the light-emitting elements different from each other, but in this embodiment, the oscillation states of the light-emitting elements are made different in a different way.

[0071] In this embodiment, the brightness of the light emitted from each of the light-emitting elements of the red light source unit 21, the green light source unit 22, and the blue light source unit 23 is adjusted by controlling them using pulse width modulation (PWM). In PWM control, the brightness is adjusted by periodically switching on and off each light-emitting element and changing the ratio between the on time (ON time) and the off time (OFF time). Hereinafter, the ratio between the on time and the off time of each light-emitting element is referred to as the duty ratio.

[0072] 3A to 3D are diagrams showing the duty ratios of the light emitting elements 40a to 40d of the light source packages 211 to 214. The horizontal axis of each graph shown in FIGS. 3A to 3D, the red light source unit 21 of this embodiment is set to a first duty ratio D1 for the first red laser light emitting element 40a of the first red light source package 211, a second duty ratio D2 for the second red laser light emitting element 40b of the second red light source package 212, a third duty ratio D3 for the third red laser light emitting element 40c of the third red light source package 213, and a fourth duty ratio D4 for the fourth red laser light emitting element 40d of the fourth red light source package 214. The first duty ratio D1 is set to ON: 90%, OFF: 10%, the second duty ratio D2 is set to ON: 80%, OFF: 20%, the third duty ratio D3 is set to ON: 70%, OFF: 30%, and the fourth duty ratio D4 is set to ON: 60%, OFF: 40%, respectively.

[0073] In this way, red light source unit 21 differentiates duty ratios D1 to D4 of light emitting elements 40a to 40d from one another when PWM controlling light emitting elements 40a to 40d of light source packages 211 to 214. As a result, red light source unit 21 differentiates the oscillation states of red light beams LR1 to LR4 emitted from light source packages 211 to 214, thereby suppressing mutual interference between red light beams LR1 to LR4.

[0074] Furthermore, when green light source unit 22 PWM controls each of light emitting elements 50a-50d of each of light source packages 221-224, green light source unit 22 makes the duty ratios of each of light emitting elements 50a-50d different from one another, similar to red light source unit 21. This allows green light source unit 22 to suppress mutual interference between each of green light beams LG1-LG4 emitted from each of light source packages 221-224.

[0075] Furthermore, when blue light source unit 23 PWM controls each of light emitting elements 60a-60d of each of light source packages 231-234, blue light source unit 23 makes the duty ratios of each of light emitting elements 60a-60d different from one another, similar to red light source unit 21. This allows blue light source unit 23 to suppress mutual interference between each of blue light beams LB1-LB4 emitted from each of light source packages 231-234.

[0076] As described above, according to the configuration of this embodiment, the red light beams LR1 to LR4 contained in the red illumination light LR, the green light beams LG1 to LG4 contained in the green illumination light LG, and the blue light beams LB1 to LB4 contained in the blue illumination light LB can be superimposed onto the screen, which is the projection surface, to form multiple speckle patterns that do not interfere with each other. Therefore, the projector of this embodiment can also display a high-quality image with reduced speckle noise of the color illumination lights LR, LG, and LB.

[0077] [Third embodiment] Next, a third embodiment of the present invention will be described. The basic configuration of the projector of the third embodiment is the same as that of the first embodiment, but the configuration of the illumination device is different from that of the first embodiment, so a description of the basic configuration of the projector will be omitted.

[0078] FIG. 4 is a diagram showing the main configuration of red light source section 121 of this embodiment. 4, in the red light source unit 121, the light source packages 211-214 have light-emitting elements 40a-40d that are different in size. Each of the light-emitting elements 40a-40d has a light-emitting surface that emits red light beams R1-R4. Here, the light-emitting surface of the first red laser light-emitting element 40a is referred to as the first light-emitting surface 45a, the light-emitting surface of the second red laser light-emitting element 40b is referred to as the second light-emitting surface 45b, the light-emitting surface of the third red laser light-emitting element 40c is referred to as the third light-emitting surface 45c, and the light-emitting surface of the fourth red laser light-emitting element 40d is referred to as the fourth light-emitting surface 45d. The ratio of the width of the light-emitting surface 45a in the Y-axis direction to the width in the X-axis direction is referred to as the aspect ratio.

[0079] In this embodiment, the light-emitting surfaces 45a to 45d have different aspect ratios and different dimensions in the Y-axis direction. The number of modes of multimode oscillation in a laser light-emitting element changes depending on the aspect ratio of the light-emitting surface. Therefore, the light-emitting elements 40a to 40d have different oscillation states.

[0080] In this way, by varying the aspect ratios of the light-emitting surfaces 45a to 45d of the light-emitting elements 40a to 40d of the light source packages 211 to 214, the red light source unit 121 can suppress mutual interference between the red light beams LR1 to LR4 emitted from the light source packages 211 to 214.

[0081] Although not shown in the drawings in this embodiment, the green light source section and the blue light source section have the same configuration as the red light source section 121. That is, the green light source unit makes the oscillation states of the first to fourth green laser light emitting elements different from one another by making the aspect ratios of the light emitting surfaces of the first to fourth green laser light emitting elements different from one another, thereby enabling the green light source unit to suppress mutual interference between the green light beams LG1 to LG4 emitted from the first to fourth green light source packages. In addition, the blue light source unit differentiates the aspect ratios of the light-emitting surfaces of the first to fourth blue laser light-emitting elements, thereby differentiating the oscillation states of the first to fourth blue laser light-emitting elements, which allows the red light source unit to suppress mutual interference between the red light beams LR1 to LR4 emitted from the first to fourth red light source packages.

[0082] As described above, according to the configuration of this embodiment, the red light beams LR1 to LR4 contained in the red illumination light LR, the green light beams LG1 to LG4 contained in the green illumination light LG, and the blue light beams LB1 to LB4 contained in the blue illumination light LB can be superimposed onto the screen, which is the projection surface, to form multiple speckle patterns that do not interfere with each other. Therefore, the projector of this embodiment can also display a high-quality image with reduced speckle noise of the color illumination lights LR, LG, and LB.

[0083] [Fourth embodiment] Next, a fourth embodiment of the present invention will be described. The projector of the fourth embodiment differs from that of the first embodiment in the configuration of the illumination device. The following mainly describes the configuration of the illumination device. Note that the same reference numerals are used for components common to the first embodiment, and detailed descriptions are omitted.

[0084] FIG. 5 is a diagram showing a schematic configuration of the lighting device 102 of this embodiment. As shown in FIG. 5, the illumination device 102 includes an excitation light source unit 103, a first phase difference plate 73, a homogenizer optical system 74, a polarization separation element (light separation / combination element) 75, a first focusing optical system 76, a wavelength conversion element 70, a second phase difference plate 78, a second focusing optical system 79, a diffusion device 26, and a superposition optical system 90.

[0085] Of these components, the excitation light source unit 103, the first phase difference plate 73, the homogenizer optical system 74, the polarization separation element 75, the second phase difference plate 78, the second focusing optical system 79, and the diffusion device 26 are arranged in sequence on the optical axis ax1.

[0086] On the other hand, the wavelength conversion element 70, the first focusing optical system 76, and the polarization separation element 75 are arranged in sequence on the illumination optical axis AX3 of the illumination device 102. The optical axis ax1 and the illumination optical axis AX3 are in the same plane and are positioned so as to be perpendicular to each other.

[0087] The excitation light source section 103 of this embodiment has the same configuration as the blue light source section 23 in the illumination device 2 of the first embodiment. The optical axis ax1 of the excitation light source section 103 is perpendicular to the illumination optical axis AX3 of the illumination device 102. 2B , excitation light source unit 103 has four light source packages arranged in one direction: first blue light source package 231, second blue light source package 232, third blue light source package 233, and fourth blue light source package 234. In the present embodiment, first blue laser light emitting element 60a of first blue light source package 231 corresponds to the "first laser light emitting element" in the claims, and second blue laser light emitting element 60b of second blue light source package 232 corresponds to the "second laser light emitting element" in the claims.

[0088] Based on this configuration, the excitation light source unit 103 of this embodiment can emit excitation light BL, which is made up of a plurality of blue light beams as parallel light, with mutual interference suppressed by making the oscillation states of the laser light emitting elements different from each other.

[0089] The excitation light BL emitted from the excitation light source unit 103 is incident on the first retardation plate 73. The first retardation plate 73 is, for example, a rotatable half-wave plate. The excitation light BL emitted from the excitation light source unit 103 is linearly polarized light. Therefore, by appropriately setting the rotation angle of the first retardation plate 73 made of a half-wave plate, the excitation light BL transmitted through the first retardation plate 73 can be converted into light containing a predetermined ratio of light beams BLs, which are S-polarized components relative to the polarization separation element 75, and light beams BLp, which are P-polarized components.

[0090] The light including the light beams BLs and BLp enters the homogenizer optical system 74 . The homogenizer optical system 74 cooperates with the first focusing optical system 76 to homogenize the illuminance distribution of the light beam BLs on the wavelength conversion element 70. The homogenizer optical system 74 also cooperates with the second focusing optical system 79 to homogenize the illuminance distribution of blue light BLc1 (described later) on the diffusion device 26.

[0091] The homogenizer optical system 74 is composed of, for example, a first multi-lens array 74a and a second multi-lens array 74b. The first multi-lens array 74a includes a plurality of first lenses 74am, and the second multi-lens array 74b includes a plurality of second lenses 74bm. The second lenses 74bm correspond to the first lenses 74am, respectively.

[0092] The wavelength conversion element 70 and the diffusion device 26 are each disposed at a position optically conjugate with the first multi-lens array 74a (first lens 74am). Also, the light emission region of the excitation light source unit 103 is disposed at a position optically conjugate with the second multi-lens array 74b.

[0093] The polarization separation element 75 is disposed at the intersection of the optical axis ax1 and the illumination optical axis AX3, which are orthogonal to each other. The polarization separation element 75 has a polarization separation function that separates the light that has passed through the first retardation plate 73 into an S-polarized component and a P-polarized component relative to the polarization separation element 75. Specifically, the polarization separation element 75 reflects a light ray BLs that is an S-polarized component of the incident light, and transmits a light ray BLp that is a P-polarized component of the incident light.

[0094] The light ray BLs, which is an S-polarized component, is reflected by the polarization separation element 75 and proceeds toward the wavelength conversion element 70. The light ray BLp, which is a P-polarized component, is transmitted through the polarization separation element 75 and proceeds toward the diffusion device 26. In other words, the polarization separation element 75 causes the light ray BLs, which is a part of the excitation light BL incident from the excitation light source unit 103, to be incident on the wavelength conversion element 70, and causes the light ray BLp, which is the other part of the excitation light BL, to be incident on the diffusion member 28 of the diffusion device 26.

[0095] The polarization separation element 75 also has a color separation function of transmitting fluorescence YL, which will be described later and which has a wavelength band different from that of the excitation light BL from the excitation light source unit 103, regardless of its polarization state.

[0096] The S-polarized light beam BLs emitted from the polarization separation element 75 is incident on the first focusing optical system 76. The first focusing optical system 76 focuses the light beam BLs toward the wavelength conversion element 70. The first focusing optical system 76 is composed of, for example, pickup lenses 76a and 76b. The light beam BLs emitted from the first focusing optical system 76 is incident on the wavelength conversion element 70.

[0097] The wavelength conversion element 70 converts the incident light beam BLs into fluorescent light (converted light) YL of a different wavelength band. The wavelength conversion element 70 is excited by the light beam BLs incident thereon as excitation light, and emits yellow fluorescence YL containing red and green light from its surface. 12 cerium ions (e.g., Ce) are added to the garnet crystal (YAG) of 3+ ) is used. The wavelength conversion element 70 may include an appropriate scattering element (not shown). The fluorescence YL emitted from the wavelength conversion element 70 is collimated by the first light-collecting optical system 76 and passes through the polarization separation element 75 .

[0098] On the other hand, the P-polarized light ray BLp emitted from the polarization separation element 75 is incident on the second retardation plate 78. The second retardation plate 78 is composed of a quarter-wave plate (λ / 4 plate) arranged in the optical path between the polarization separation element 75 and the diffuser 26. By transmitting through the second retardation plate 78, the light ray BLp is converted into, for example, right-handed circularly polarized blue light BLc1. The blue light BLc1 transmitted through the second retardation plate 78 is incident on the second light-collecting optical system 79.

[0099] The second light-collecting optical system 79 collects the blue light BLc1 toward the diffusion device 26. The second light-collecting optical system 79 is made up of, for example, a pickup lens 79a and a pickup lens 79b.

[0100] The diffusion device 26 diffuses and reflects the blue light BLc1 emitted from the second light collecting optical system 79 toward the polarization separation element 75. In the present embodiment, the diffusion device 26 is disposed such that the diffusion member 28 is oriented perpendicular to the incident direction of the light.

[0101] Hereinafter, the blue light BLc1 diffusely reflected by the diffuser 26 will be referred to as blue light BLc2. According to this embodiment, blue light BLc2 with a substantially uniform illuminance distribution is obtained by diffusing and reflecting the blue light BLc1. For example, right-handed circularly polarized blue light BLc1 is reflected as left-handed circularly polarized blue light BLc2.

[0102] The blue light BLc2 is converted into parallel light by the second focusing optical system 79 and then enters the second retardation plate 78 again. The left-handed circularly polarized blue light BLc2 is converted into S-polarized blue light BLs1 by the second retardation plate 78. The S-polarized blue light BLs1 is reflected by the polarization separation element 75 toward the superimposing optical system 90.

[0103] The polarization separation element 75 combines the fluorescence YL, which is the converted light emitted from the wavelength conversion element 70, with the blue light BLs1, which is the diffused light diffused by the diffusion member 28 of the diffusion device 26, to generate white light (composite light) WL1, and emits the white light WL1 toward the superimposition optical system 90.

[0104] The superimposing optical system 90 includes an integrator optical system 91, a polarization conversion element 92, and a superimposing lens 93. The superimposing optical system 90 homogenizes the intensity distribution of the white light WL1 in the illuminated area. The white light WL1 emitted from the superimposing optical system 90 enters the color separation optical system 3.

[0105] Specifically, the integrator optical system 91 is made up of, for example, a lens array 91a and a lens array 91b. The lens arrays 91a and 91b are made up of a plurality of lenses arranged in an array.

[0106] The lens array 91b, together with the superimposing lens 93, forms images of the lenses of the lens array 91a near the image forming areas of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, respectively.

[0107] The white light WL1 that has passed through the integrator optical system 91 is incident on a polarization conversion element 92. The polarization conversion element 92 is composed of, for example, a polarization separation film and a retardation plate, and converts the white light WL1 into linearly polarized light. Note that the polarization conversion element 92 may be omitted if necessary.

[0108] The white light WL1 that has passed through the polarization conversion element 92 is incident on the superimposing lens 93. The superimposing lens 93 collects the partial light beams emitted from the polarization conversion element 92 and superimposes them near the image formation areas of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B. In this embodiment, the integrator optical system 91 and the superimposing lens 93 homogenize the illuminance distribution in the illuminated area.

[0109] The blue light BLs1 contained in the white light WL1 is laser light, and is incident on the light modulation device 4B as blue light BL to generate a blue image in the projected image, which may cause speckle noise. In contrast, according to the illumination device 102 of the present embodiment, the excitation light BL consisting of a plurality of blue light beams in which mutual interference is suppressed is emitted by varying the oscillation states of the light emitting elements 60a-60d of the light source packages 231-234 in the excitation light source section 103, and the blue light BLs1 is diffused by the diffusion member 28 of the diffusion device 26. As a result, the blue light BLs1 superimposes a plurality of speckle patterns on the screen that do not interfere with each other, making it possible to display a high-quality image with reduced speckle noise of the blue light BL.

[0110] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0111] In the above embodiment, examples of configurations for making the oscillation states of each light-emitting element different from one another include making the drive frequencies of the laser light-emitting elements different, making the duty ratios of the PWM control of the laser light-emitting elements different, or making the aspect ratios of the light-emitting surfaces of the laser light-emitting elements different, but the present invention is not limited to this.

[0112] For example, the red light source unit 21 may employ light source packages 211-214 manufactured by different manufacturers. Generally, packages manufactured by different manufacturers have different constituent materials or composition ratios of the light emitting elements, or even if the constituent materials are the same, the composition ratios are different. Here, the composition ratio means, for example, differences in the types and proportions of impurities contained in the cladding layer.

[0113] In this way, light emitting elements with different constituent materials or composition ratios will have different oscillation states. In other words, by configuring each light source package 211 to 214 using packages from different manufacturers, it is possible to reduce speckle noise in the red illumination light LR.

[0114] The same can be said about the green light source unit 22 or the blue light source unit 23 as about the red light source unit 21. That is, by using packages from different manufacturers for the light source packages 221 to 224 of the green light source unit 22, it is possible to reduce speckle noise in the green illumination light LG. Also, by using packages from different manufacturers for the light source packages 231 to 234 of the blue light source unit 23, it is possible to reduce speckle noise in the blue illumination light LB.

[0115] Furthermore, although the above-described embodiments have been described with reference to an example in which each of the light source units 21, 22, and 23 includes a plurality of light source packages, each of the light source units 21, 22, and 23 may include one light source package. For example, taking the red light source unit 21 as an example, the red light source unit 21 is composed of only a first red light source package 211, and the oscillation states of the plurality of first red laser light emitting elements 40a in the first red light source package 211 are different from one another. In this configuration, one of the plurality of first red laser light emitting elements 40a corresponds to the "first laser light emitting element" in the claims, and another of the plurality of first red laser light emitting elements 40a corresponds to the "second laser light emitting element" in the claims. Similarly, the green light source unit 22 may be composed of only a first green light source package 221, and the oscillation states of the plurality of first green laser light emitting elements 50a in the first green light source package 221 may be made different from one another. The blue light source unit 23 may be composed of only a first blue light source package 231, and the oscillation states of the plurality of first blue laser light emitting elements 60a in the first blue light source package 231 may be made different from one another.

[0116] Furthermore, in the above embodiment, an example has been given in which the oscillation states of the light-emitting elements in each of the light source units 21, 22, and 23 are different from one another, but speckle noise may be reduced by differentiating the oscillation states of at least one of the light-emitting elements in each of the light source units 21, 22, and 23. Note that when the present invention is applied to only one of the light source units 21, 22, and 23, it is desirable to apply the present invention to the red light source unit 21 that emits red illumination light LR in which speckle noise is easily noticeable.

[0117] Although the lighting device in the above embodiment includes a rotatable diffuser, the diffuser does not necessarily have to be rotatable and may be fixed.

[0118] In addition, the specific descriptions of the shape, number, arrangement, materials, etc. of each component of the lighting device and the projector are not limited to the above embodiments and can be modified as appropriate. Furthermore, in the above embodiments, an example was shown in which the lighting device of the present invention is mounted on a projector using a liquid crystal panel, but this is not limiting. The lighting device of the present invention may also be applied to a projector that uses a digital micromirror device as a light modulation device. Furthermore, the projector does not need to have multiple light modulation devices, and may be a single-panel projector that has only one light modulation device.

[0119] In the above embodiment, the illumination device of the present invention is applied to a projector, but the present invention is not limited to this. The illumination device of the present invention can also be applied to lighting fixtures, automobile headlights, and the like.

[0120] Summary of this disclosure A summary of this disclosure is provided below.

[0121] (Appendix 1) a first laser light emitting element that emits a first light; a second laser light emitting element that emits a second light having the same peak wavelength as the first light; a diffusing member onto which the first light and the second light are incident; a superimposing optical system into which the light emitted from the diffusing member is incident; a light modulation device that modulates the light incident from the superimposing optical system in accordance with image information; a projection optical device that projects the light modulated by the light modulation device; Equipped with The first laser light-emitting element and the second laser light-emitting element have different oscillation states. projector.

[0122] With this configuration of the projector, mutual interference between the first light and the second light emitted from each laser light-emitting element can be suppressed by varying the oscillation state of each laser light-emitting element, which allows the first light and the second light to be superimposed on the projection surface to form speckle patterns that do not interfere with each other. Therefore, a projector with this configuration can display a high-quality image with reduced speckle noise.

[0123] (Appendix 2) a first light source package having a package structure in which a plurality of the first laser light emitting elements are mounted; a second light source package having a package structure in which a plurality of the second laser light emitting elements are mounted; Equipped with 1. The projector according to claim 1.

[0124] According to this configuration, since the first light source package and the second light source package are provided with a so-called multi-emitter package structure, it is possible to generate high-brightness light with reduced speckle noise while miniaturizing the device configuration. can.

[0125] (Appendix 3) a first driving frequency of the first laser light emitting element of the first light source package and a second driving frequency of the second laser light emitting element of the second light source package are different from each other; 2. The projector according to claim 1,

[0126] According to this configuration, by varying the duty ratio by pulse width modulation control, it is possible to easily realize a configuration in which the oscillation states of the first laser light-emitting element and the second laser light-emitting element are made different from each other.

[0127] (Appendix 4) the first drive frequency and the second drive frequency are not integer multiples of each other; 2. The projector according to claim 1, wherein the projector is a

[0128] According to this configuration, one of the drive frequencies of the first light source package and the second light source package is not included in the other, which makes it possible to more effectively suppress mutual interference between the first light and the second light.

[0129] (Appendix 5) When driving the first laser light emitting element of the first light source package and the second laser light emitting element of the second light source package is controlled by pulse width modulation, a first duty ratio for controlling the first laser light-emitting element and a second duty ratio for controlling the second laser light-emitting element are different from each other; 2. The projector according to claim 1,

[0130] According to this configuration, by varying the duty ratio by pulse width modulation control, it is possible to easily realize a configuration in which the oscillation states of the first laser light-emitting element and the second laser light-emitting element are made different from each other.

[0131] (Appendix 6) a first aspect ratio of the first light-emitting surface of the first laser light-emitting element and a second aspect ratio of the second light-emitting surface of the second laser light-emitting element are different from each other; 1. The projector according to claim 1 or 2.

[0132] According to this configuration, by making the aspect ratios of the light-emitting surfaces different, it is possible to easily realize a configuration in which the oscillation states of the first laser light-emitting element and the second laser light-emitting element are made different from each other.

[0133] (Appendix 7) The first laser light-emitting element and the second laser light-emitting element are made of different materials or have different composition ratios. 1. The projector according to claim 1 or 2.

[0134] According to this configuration, by varying the constituent materials or composition ratio of the light emitting elements, it is possible to easily realize a configuration in which the oscillation states of the first laser light emitting element and the second laser light emitting element are made different from each other.

[0135] (Appendix 8) a wavelength conversion element that converts incident light into converted light of a different wavelength band; a light separating / combining element to which the first light and the second light are incident, causing a portion of the first light and the second light to be incident on the wavelength conversion element, and causing another portion of the first light and the second light to be incident on the diffusion member; Furthermore, the light separation / combination element combines the converted light emitted from the wavelength conversion element and the diffused light diffused by the diffusing member, and emits the combined illumination light toward the superimposing optical system. 8. The projector according to claim 1, wherein the projector is a

[0136] According to this configuration, when light is generated by combining light wavelength-converted by a wavelength conversion element with light diffused by a diffusing member, speckle noise caused by diffused light can be suppressed.

[0137] (Appendix 9) the first light and the second light are red light; 9. The projector according to any one of claims 1 to 8.

[0138] This configuration can reduce speckle noise in red light, which is highly visible to humans, and therefore can efficiently achieve the effect of reducing speckle noise.

[0139] (Appendix 10) a third laser light emitting element that emits a third light having a wavelength band different from that of the first light; a fourth laser light emitting element that emits a fourth light having the same peak wavelength as the third light; a fifth laser light emitting element that emits fifth light having a wavelength band different from that of the first light and the third light; a sixth laser light emitting element that emits sixth light having the same peak wavelength as the fifth light; a light combining unit that combines the first light, the second light, the third light, the fourth light, the fifth light, and the sixth light and emits a combined light; Furthermore, the third light and the fourth light are blue light, and the fifth light and the sixth light are green light; the third laser light-emitting element and the fourth laser light-emitting element have different oscillation states, the fifth laser light-emitting element and the sixth laser light-emitting element have different oscillation states, The combined light emitted from the light combining unit is incident on the diffusing member. 10. The projector according to claim 9.

[0140] This configuration makes it possible to reduce speckle noise in white light made up of laser light containing red, green, and blue light, thereby providing a projector that projects full-color images with reduced speckle noise. [Explanation of symbols]

[0141] 1...projector, 4B, 4G, 4R...light modulation device, 6...projection optical device, 24...light combining section, 28...diffusion member, 30, 90...superimposing optical system, 40a...first red laser light emitting element (first laser light emitting element), 40b...second red laser light emitting element (second laser light emitting element), 45a...first light emitting surface, 45b...second light emitting surface, 50a...first green laser light emitting element (third laser light emitting element), 50b...second green laser light emitting element (fourth laser light emitting element), 60a...first blue laser light emitting element (fifth laser light emitting element), 60b...second blue laser light emitting element (sixth laser light emitting element) optical element), 70...wavelength conversion element, 75...polarization separation element (light separation / synthesis element), 211...first red light source package (first light source package), 212...second red light source package (second light source package), B1...blue light ray (fifth light), B2...blue light ray (sixth light), D1...first duty ratio, D2...second duty ratio, F1...first drive frequency, F2...second drive frequency, G1...green light ray (third light), G2...green light (fourth light), GL...green light, R1...red light ray (first light), R2...red light (second light), RL...red light, WL1...white light (synthesized light), YL...fluorescence (converted light).

Claims

1. a first laser light emitting element that emits a first light; a second laser light emitting element that emits a second light having the same peak wavelength as the first light; a diffusing member onto which the first light and the second light are incident; a superimposing optical system into which the light emitted from the diffusing member is incident; a light modulation device that modulates the light incident from the superimposing optical system in accordance with image information; a projection optical device that projects the light modulated by the light modulation device; Equipped with The first laser light-emitting element and the second laser light-emitting element have different oscillation states. projector.

2. a first light source package having a package structure in which a plurality of the first laser light emitting elements are mounted; a second light source package having a package structure in which a plurality of the second laser light emitting elements are mounted; Equipped with The projector according to claim 1 .

3. a first driving frequency of the first laser light-emitting element of the first light source package and a second driving frequency of the second laser light-emitting element of the second light source package are different from each other; The projector according to claim 2 .

4. the first drive frequency and the second drive frequency are not integer multiples of each other; The projector according to claim 3 .

5. When driving the first laser light emitting element of the first light source package and the second laser light emitting element of the second light source package is controlled by pulse width modulation, a first duty ratio for controlling the first laser light-emitting element and a second duty ratio for controlling the second laser light-emitting element are different from each other; The projector according to claim 2 .

6. a first aspect ratio of the first light-emitting surface of the first laser light-emitting element and a second aspect ratio of the second light-emitting surface of the second laser light-emitting element are different from each other; 3. The projector according to claim 1.

7. the first laser light-emitting element and the second laser light-emitting element are different from each other in terms of constituent materials or constituent ratios; 3. The projector according to claim 1.

8. a wavelength conversion element that converts incident light into converted light of a different wavelength band; a light separating / combining element to which the first light and the second light are incident, causing a portion of the first light and the second light to be incident on the wavelength conversion element, and causing another portion of the first light and the second light to be incident on the diffusion member; Furthermore, the light separation / combination element combines the converted light emitted from the wavelength conversion element and the diffused light diffused by the diffusing member, and emits the combined illumination light toward the superimposing optical system.

3. The projector according to claim 1.

9. the first light and the second light are red light; 3. The projector according to claim 1.

10. a third laser light emitting element that emits a third light having a wavelength band different from that of the first light; a fourth laser light emitting element that emits fourth light having the same peak wavelength as the third light; a fifth laser light-emitting element that emits fifth light having a wavelength band different from that of the first light and the third light; a sixth laser light emitting element that emits sixth light having the same peak wavelength as the fifth light; a light combining unit that combines the first light, the second light, the third light, the fourth light, the fifth light, and the sixth light and emits a combined light; Furthermore, the third light and the fourth light are blue light, and the fifth light and the sixth light are green light; the third laser light-emitting element and the fourth laser light-emitting element have different oscillation states, the fifth laser light-emitting element and the sixth laser light-emitting element have different oscillation states, The combined light emitted from the light combining unit is incident on the diffusing member. The projector according to claim 9.

Images