Lighting device and projector

Abstract

To provide a lighting device and a projector capable of reducing an uneven illumination due to interferences of light.SOLUTION: A lighting device according to the present invention comprises: a first light source for emitting first light of a first wavelength band; a second light source for emitting second light of a second wavelength band; a light synthesizing member for synthesizing the first light and the second light and emitting synthesized light; a diffusion device including a base plate having a diffusion surface for diffusing and emitting the synthesized light and a drive device for rotating the base plate; a condensing element for condensing the synthesized light toward the diffusion device, being located between the light synthesizing member and the diffusion device; a collimator element for parallelizing the synthesized light emitted from the diffusion device; a light uniformizing element having a first lens array surface which the synthesized light from a collimator lens enters and a second lens array surface for emitting light having entered from the first lens array surface, with the first lens array surface and the second lens array surface being integrated; a swing device for swinging the light uniformizing element; and a superposition lens for superposing the light emitted from the light uniformizing element.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a lighting device and a projector.

Background Art

[0002] For the purpose of improving the performance of projectors, projectors equipped with lighting devices using laser light sources, which are light sources with a wide color gamut and high efficiency, have been proposed. Patent Document 1 below discloses a lighting device including a blue light source array, a red light source array, a green light source array, a color synthesis optical system, a condenser lens, a diffusion plate, and a multi-lens array.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above lighting device, since a plurality of lenses are regularly arranged in the multi-lens array, light spread by each lens or diffracted light generated between adjacent lenses may overlap and cause interference. For this reason, there has been a problem that uneven illuminance due to light interference occurs in the projected image by the above projector.

Means for Solving the Problems

[0005] In order to solve the above problems, according to one aspect of the present invention, there is provided an illumination device including: a first light source that emits first light in a first wavelength band; a second light source that emits second light in a second wavelength band different from the first wavelength band; a light combining member that combines the first light and the second light to emit combined light; a light homogenizing element having a first lens array surface on which the combined light is incident and a second lens array surface that emits light passing through the first lens array surface, the first lens array surface and the second lens array surface being integrated; a swinging device that swings the light homogenizing element; and a superimposing lens that superimposes the light emitted from the light homogenizing element.

[0006] Further, according to another aspect of the present invention, there is provided a projector including: the illumination device according to the above aspect; a light modulation device that modulates the light emitted from the illumination device; and a projection optical device that projects the light modulated by the light modulation device.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0008] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the drawings used in the following description may show the characteristic parts enlarged for easy understanding of the characteristics, and the dimensional ratios of the respective components are not necessarily the same as the actual ones.

[0009] Hereinafter, an embodiment of the present invention will be described. FIG. 1 is a schematic configuration diagram showing a projector according to an embodiment. As shown in FIG. 1, the projector 1 of the present 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, a light modulation device 4R, a light modulation device 4G, a light modulation device 4B, a synthesis optical system 5, and a projection optical device 6.

[0010] The illumination device 2 emits white illumination light WL toward the color separation optical system 3. The configuration of the illumination device 2 will be described in detail later.

[0011] The color separation optical system 3 separates the illumination light WL into red illumination light R, green illumination light G, and blue illumination light B. The color separation optical system 3 includes a dichroic mirror 7a and a dichroic mirror 7b, a total reflection mirror 8a, a total reflection mirror 8b, and a total reflection mirror 8c, and a first relay lens 9a and a second relay lens 9b. Hereinafter, red, green, and blue may be collectively referred to as RGB colors.

[0012] The dichroic mirror 7a separates the illumination light WL from the illumination device 2 into red illumination light R and other light (green illumination light G and blue illumination light B). The dichroic mirror 7a transmits the red illumination light R and reflects the other light. The dichroic mirror 7b reflects the green illumination light G and transmits the blue illumination light B.

[0013] The total reflection mirror 8a reflects the red illumination light R toward the optical modulation device 4R. The total reflection mirrors 8b and 8c guide the blue illumination light B to the optical modulation device 4B. The green illumination light G is reflected from the dichroic mirror 7b toward the optical modulation device 4G.

[0014] The first relay lens 9a and the second relay lens 9b are arranged at the subsequent stage of the dichroic mirror 7b in the optical path of the blue illumination light B.

[0015] The optical modulation device 4R modulates the red illumination light R according to the image information to form red image light. The optical modulation device 4G modulates the green illumination light G according to the image information to form green image light. The optical modulation device 4B modulates the blue illumination light B according to the image information to form blue image light.

[0016] For the optical modulation devices 4R, 4G, and 4B, for example, transmissive liquid crystal panels are used. Also, polarizing plates (not shown) are arranged on each of the incident side and the emission side of the liquid crystal panel.

[0017] Also, field lenses 10R, 10G, and 10B are arranged on the incident sides of the optical modulation devices 4R, 4G, and 4B, respectively.

[0018] Each image light from the optical modulation devices 4R, 4G, and 4B is incident on the synthesis optical system 5. The synthesis optical system 5 synthesizes each image light and emits the synthesized image light toward the projection optical device 6. For example, a cross dichroic prism is used for the synthesis optical system 5.

[0019] The projection optical device 6 consists of a projection lens group and enlarges and projects the image light synthesized by the synthesis optical system 5 toward the screen SCR. Thereby, an enlarged color video is displayed on the screen SCR.

[0020] Next, the lighting device 2 according to an embodiment of the present invention will be described. FIG. 2 is a diagram showing a schematic configuration of the lighting device 2. As shown in FIG. 2, the lighting device 2 includes a light source device 20, a condenser element 26, a rotary diffusion device 23, a collimator element 25, a light homogenizing element 50, a superimposing lens 52, and a swinging device 30.

[0021] The light source device 20 includes a red light source (first light source) 20R, a green light source (second light source) 20G, a blue light source (third light source) 20B, and a light combining member 24. In the present embodiment, the red light source 20R, the light combining member 24, and the blue light source 20B are provided on the optical axis ax1 of the red light source 20R. The green light source 20G, the light combining member 24, the condenser element 26, and the rotary diffusion device 23 are provided on the optical axis ax2 of the green light source 20G. Further, the rotary diffusion device 23, the collimator element 25, the light homogenizing element 50, and the superimposing lens 52 are provided on the illumination optical axis AX of the lighting device 2. Note that the optical axis of the blue light source 20B coincides with the optical axis ax1 of the red light source 20R, and the optical axis of the green light source 20G coincides with the illumination optical axis AX. Also, the optical axis ax1 and the optical axis ax2 are orthogonal to each other, and the optical axis ax1 and the illumination optical axis AX are parallel to each other.

[0022] Hereinafter, when describing the shape and arrangement of the constituent members of the lighting device 2, an XYZ coordinate system may be used. In this specification, the direction in which green light LG is emitted from the green light source 20G and along the optical axis ax2 is defined as the X direction, the direction along the illumination optical axis AX of the lighting device 2 is defined as the Y direction, and the direction perpendicular to the X direction and the Y direction is defined as the Z direction for explanation.

[0023] The red light source 20R includes a plurality of red semiconductor lasers 21R and a plurality of collimator lenses 22R. The green light source 20G includes a plurality of green semiconductor lasers 21G and a plurality of collimator lenses 22G. The blue light source 20B includes a plurality of blue semiconductor lasers 21B and a plurality of collimator lenses 22B. That is, each of the light sources 20R, 20G, and 20B is a laser light source.

[0024] The plurality of red semiconductor lasers 21R are arranged in an array in a plane orthogonal to the optical axis ax1. Each red semiconductor laser 21R emits a red light beam Br in a first wavelength band of, for example, 585 nm to 720 nm. The plurality of collimator lenses 22R are respectively arranged corresponding to the plurality of red semiconductor lasers 21R, and convert the red light beam Br emitted from the corresponding laser into parallel light. Based on such a configuration, the red light source 20R emits a red light LR including a plurality of red light beams Br formed of parallel light beams toward the light combining member 24.

[0025] The plurality of green semiconductor lasers 21G are arranged in an array in a plane orthogonal to the illumination optical axis AX. Each green semiconductor laser 21G emits a green light beam Bg in a second wavelength band different from the first wavelength band of, for example, 495 nm to 585 nm. The plurality of collimator lenses 22G are respectively arranged corresponding to the plurality of green semiconductor lasers 21G, and convert the green light beam Bg emitted from the corresponding laser into parallel light. Based on such a configuration, the green light source 20G emits a green light LG including a plurality of green light beams Bg formed of parallel light beams toward the light combining member 24.

[0026] The plurality of blue semiconductor lasers 21B are arranged in an array in a plane orthogonal to the optical axis ax2. Each blue semiconductor laser 21B emits a blue light beam Bb in a third wavelength band different from the first and second wavelength bands of, for example, 380 nm to 495 nm. The plurality of collimator lenses 22B are respectively arranged corresponding to the plurality of blue semiconductor lasers 21B, and convert the blue light beam Bb emitted from the corresponding laser into parallel light. Based on such a configuration, the blue light source 20B emits a blue light LB including a plurality of blue light beams Bb formed of parallel light beams toward the light combining member 24.

[0027] The photosynthetic member 24 synthesizes white illumination light WL composed of RGB lights of respective colors (red light LR, green light LG, and blue light LB) emitted from the light source device 20, and emits the white illumination light WL in one direction and makes it incident on the condenser element 26. The condenser element 26 condenses the illumination light WL at a predetermined position.

[0028] The photosynthetic member 24 is composed of a cross dichroic prism. The cross dichroic prism has a first dichroic mirror 24a and a second dichroic mirror 24b. The first dichroic mirror 24a and the second dichroic mirror 24b are each arranged so as to intersect the optical axis ax1 and the optical axis ax2 at 45°. Further, the first dichroic mirror 24a and the second dichroic mirror 24b intersect at an angle of 45° with each other.

[0029] The first dichroic mirror 24a has optical characteristics of reflecting the blue light LB and transmitting the green light LG and the red light LR. The second dichroic mirror 24b has optical characteristics of reflecting the red light LR and transmitting the blue light LB and the green light LG.

[0030] The condenser element 26 makes the illumination light WL incident on the rotary diffusion device 23 while condensing the illumination light WL. The rotary diffusion device 23 equalizes the illuminance distribution of the illumination light WL by diffusing the illumination light WL. The rotary diffusion device 23 has a diffusion plate 231 rotatable about a predetermined rotation axis and a drive device 232 composed of a motor. The diffusion plate 231 is configured, for example, by forming an uneven structure on the surface of a disk made of a metal such as aluminum by, for example, an etching process or a blasting process. The rotary diffusion device 23 is arranged so as to intersect the optical axis ax2 and the illumination optical axis AX at 45°.

[0031] The collimator element 25 collimates the illumination light WL emitted from the rotary diffusion device 23 and emits it toward the light homogenizing element 50. In the case of the present embodiment, the collimator element 25 is composed of one convex lens. Note that the collimator element 25 may be composed of a plurality of lenses.

[0032] The light homogenizing element 50, together with the superimposed lens 52, homogenizes the illuminance distribution of the illumination light WL emitted from the collimator element 25 in each image generation region of the light modulation devices 4R, 4G, and 4B.

[0033] The light homogenizing element 50 of the present embodiment is composed of a double-sided multi-lens array in which the first lens array surface 51a and the second lens array surface 51b are integrated. That is, the light homogenizing element 50 of the present embodiment is composed of one optical member in which the first lens array surface 51a and the second lens array surface 51b are integrally formed. Note that the pitch of the multi-lens array constituting the light homogenizing element 50 of the present embodiment is preferably set to, for example, 0.1 mm or more and 1 mm or less. Thereby, the light homogenizing element 50 is composed of a narrow pitch microlens array unit, and the light homogenizing performance can be enhanced by increasing the number of light source images superimposed on the illuminated region.

[0034] The first lens array surface 51a is a surface on which the illumination light WL emitted from the collimator element 25 is incident. The first lens array surface 51a includes a plurality of first small lenses 53 for dividing the illumination light WL into a plurality of partial light beams. The plurality of first small lenses 53 are arranged in a matrix in a plane orthogonal to the illumination optical axis AX.

[0035] The second lens array surface 51b is a surface that emits the plurality of partial light beams divided via the first lens array surface 51a. The second lens array surface 51b includes a plurality of second small lenses 54 corresponding to the respective first small lenses 53 of the first lens array surface 51a. The second lens array surface 51b, together with the superimposed lens 52 in the subsequent stage, forms an image of each first small lens 53 of the first lens array surface 51a in or near each image generation region of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B. The plurality of second small lenses 54 are arranged in a matrix in a plane orthogonal to the illumination optical axis AX.

[0036] The superimposing lens 52 condenses each of the plurality of partial light beams emitted from the light homogenizing element 50 and superimposes them on each other in or near the image generation regions of the light modulation devices 4R, 4G, and 4B.

[0037] The light homogenizing element 50 is housed in a holder 55. The holder 55 is a rubber-like member that surrounds the outer peripheral portion 510 of the light homogenizing element 50 in a frame shape. The swinging device 30 is arranged in contact with the holder 55 and swings the light homogenizing element 50 via the holder 55. The holder 55 of the present embodiment holds the light homogenizing element 50 while restricting the rotation of the light homogenizing element 50 around the Z-axis or the X-axis.

[0038] The swinging device 30 integrally swings the first lens array surface 51a and the second lens array surface 51b along a direction orthogonal to the optical axis of the light homogenizing element 50. Here, the fact that the first lens array surface 51a and the second lens array surface 51b swing integrally means that the positional relationship between the first lens array surface 51a and the second lens array surface 51b does not change even when the light homogenizing element 50 is swung by the swinging device 30.

[0039] More specifically, the swinging device 30 integrally swings the first lens array surface 51a and the second lens array surface 51b along the X direction (first direction) orthogonal to the optical axis of the light homogenizing element 50 and the Z direction (second direction) orthogonal to the optical axis and the X direction. The light homogenizing element 50 swings while the rotation around the Z-axis or the X-axis is suppressed by the holder 55.

[0040] Here, in the projector 1 of the present embodiment, the first lens array surface 51a of the light homogenizing element 50 is in an optically conjugate relationship with the image generation regions that generate images in the light modulation devices 4R, 4G, and 4B. Therefore, each of the first small lenses 53 on the first lens array surface 51a has a rectangular shape that is substantially similar to the shape of the image generation regions of the light modulation devices 4R, 4G, and 4B.

[0041] On one hand, the screen surface that projects the image light generated in each image generation area of the optical modulation devices 4R, 4G, and 4B and each image generation area of the optical modulation devices 4R, 4G, and 4B are in an optically conjugate relationship. That is to say, it can be said that the first lens array surface 51a that is in a conjugate relationship with the image generation area is indirectly in a conjugate relationship with the screen surface.

[0042] In the projector 1 of the present embodiment, by swinging the first lens array surface 51a of the light homogenizing element 50 that is in a conjugate relationship with the screen surface, it is possible to make it difficult to visually recognize the uneven illuminance of the projected image as described later.

[0043] The frequency of the swing generated by the swing device 30 is preferably 60 Hz or more and 500 Hz or less. This is because if the frequency is less than 60 Hz, flicker will occur in the projected image. Also, if the frequency is higher than 500 Hz, it is necessary to further enhance the robustness of the swing device 30 itself and the device body of the lighting device that houses the swing device 30, which becomes a factor in cost increase. Therefore, in the projector 1 of the present embodiment, by setting the frequency of the swing of the swing device 30 to 60 Hz or more and 500 Hz or less, a configuration for reducing uneven illuminance while suppressing flicker can be realized at low cost. Also, the amplitude of the light homogenizing element 50 by the swing device 30 is, for example, 150 μm. Note that the amplitude of the light homogenizing element 50 is not limited to the above value and is appropriately adjusted according to the pitch of the lens array surface and the period of the interference fringes that cause uneven illuminance.

[0044] FIG. 3 is a diagram showing the configuration of the light homogenizing element 50. As shown in FIG. 3, the focal point P1 of each of the plurality of second small lenses 54 on the second lens array surface 51b is arranged on the light incident surface 53a of the corresponding first small lens 53 among the plurality of first small lenses 53. For this reason, the light incident from the light incident surface 53a of each first small lens 53 is emitted as parallel light from the corresponding second small lens 54.

[0045] In addition, the focal point P2 of each of the plurality of first small lenses 53 on the first lens array surface 51a is disposed on the light emitting surface 54a of the corresponding second small lens 54 among the plurality of second small lenses 54. Therefore, since the partial light beam split by the first small lens 53 is focused on the light emitting surface 54a of each second small lens 54, the second small lens 54 can efficiently capture and emit the light from the first small lens 53. Thus, the light loss in the light homogenizing element 50 can be reduced.

[0046] FIG. 4 is a diagram showing an example of the configuration of the swing device 30. As shown in FIG. 4, the swing device 30 includes a case body 31 including a contact portion 36 that contacts the light homogenizing element 50, a motor 32 including a shaft portion 33 that rotates about a rotation axis O, a rotating member 34 provided on the shaft portion 33 of the motor 32, and a bearing 37 that rotatably supports the rotating member 34. The rotation axis O is an imaginary axis passing through the center of the shaft portion 33.

[0047] The case body 31 houses the motor 32, the rotating member 34, and the bearing 37 inside. One end side of the rotating member 34 in the direction along the rotation axis O is connected to the shaft portion 33, the other end side in the direction along the rotation axis O is held by the bearing 37, and the rotating member 34 includes a weight 35 that is eccentric with respect to the rotation axis O at the central portion. Here, the weight 35 eccentric with respect to the rotation axis O means a state in which the center of gravity of the weight 35 is displaced in a direction orthogonal to the rotation axis O.

[0048] In the swing device 30, when the shaft portion 33 of the motor 32 rotates, the rotating member 34 rotates together with the shaft portion 33. At this time, since the center of gravity of the weight 35 rotates while being displaced from the rotation axis O, the motor 32 itself vibrates as it is swung by the weight 35. The vibration of the motor 32 is transmitted to the case body 31, and the light homogenizing element 50 is swung via the contact portion 36.

[0049] According to the swing device 30 of the present embodiment, with a simple configuration in which a weight 35 eccentric with respect to the rotation axis O is provided on a rotating member 34 that rotates together with the shaft portion 33 of the motor 32, it is possible to realize a configuration for swinging the light homogenizing element 50 at low cost without increasing the size of the device configuration.

[0050] Thus, the lighting device 2 of the present embodiment includes a red light source 20R that emits red light LR, a green light source 20G that emits green light LG, a blue light source 20B that emits blue light LB, a light combining member 24 that combines the red light LR, the green light LG, and the blue light LB to emit illumination light WL, a rotary diffusing device 23 that diffuses the illumination light WL, a condensing element 26 that is disposed between the light combining member 24 and the rotary diffusing device 23 and condenses the illumination light WL toward the rotary diffusing device 23, a collimator element 25 that collimates the illumination light WL emitted from the rotary diffusing device 23, a light homogenizing element 50 having a first lens array surface 51a into which the illumination light WL emitted from the collimator element 25 is incident and a second lens array surface 51b that emits the light that has passed through the first lens array surface 51a, and in which the first lens array surface 51a and the second lens array surface 51b are integrated, a swing device 30 that swings the light homogenizing element 50, and a superimposing lens 52 that superimposes the light emitted from the light homogenizing element 50.

[0051] Here, the first lens array surface 51a of the light homogenizing element 50 has a structure in which a plurality of first small lenses 53 are regularly arranged as described above. For this reason, there is a possibility that the lights divided by the plurality of first small lenses 53 on the first lens array surface 51a, or the diffracted lights generated between the ridge lines between adjacent first small lenses 53 overlap and interfere with each other.

[0052] In the case of this embodiment, since the respective color lights LR, LG, and LB included in the illumination light WL are coherent lights, light interference is likely to occur. Therefore, the light emitted from the first lens array surface 51a of the light homogenizing element 50 may cause streak-like or striped illuminance unevenness due to light interference on each image generation region of the light modulation devices 4R, 4G, and 4B and on the screen surface that are optically conjugate. Such illuminance unevenness can be a factor in reducing the visibility of the projected image. Note that the shape and interval of streaks and unevenness caused by light interference vary, for example, according to the shape of the first small lens 53 and the interval between ridge lines and the like.

[0053] On the other hand, the illumination device 2 of this embodiment can achieve the same effect as when the screen SCR is apparently swung by swinging the first lens array surface 51a, which is a conjugate surface with the screen SCR, by the swinging device 30. That is, similar to the case where the screen SCR is swung, the illuminance unevenness of the projected image by the respective color lights LR, LG, and LB is changed temporally on the screen SCR. As a result, the viewer of the projector 1 visually recognizes streaks and stripes averaged over time, making it difficult for the viewer to visually recognize the illuminance unevenness.

[0054] Further, in the illumination device 2 of this embodiment, since the respective color lights LR, LG, and LB included in the illumination light WL are coherent lights, there is a possibility of generating speckles in the projected image. On the other hand, the illumination device 2 of this embodiment can also reduce the speckle noise of the projected image by swinging the first lens array surface 51a, which is a conjugate surface with the screen SCR, by the swinging device 30.

[0055] Also, in the illumination device 2 of this embodiment, since the focal point P1 of the second small lens 54 is located on the light incident surface 53a of the first small lens 53 as described above, even when the light homogenizing element 50 swings, parallel light can be emitted from the second small lens 54. Therefore, it is possible to suppress a change in the incident angle of the light emitted from the second lens array surface 51b of the light homogenizing element 50 with respect to the superimposing lens 52.

[0056] In addition, in the case of this embodiment, when the light homogenizing element 50 is swung, in order to restrict the rotation of the light homogenizing element 50 around the Z-axis or the Y-axis, the light emitted as parallel light from the second lens array surface 51b enters the superimposing lens 52 at a predetermined angle.

[0057] Thus, even when the light homogenizing element 50 of the lighting device 2 of this embodiment is swung, the incident angle of the light from the light homogenizing element 50 in the superimposing lens 52 does not change. Therefore, the lighting area by the superimposing lens 52, that is, the lighting area on each image generation area of the light modulation devices 4R, 4G, and 4B does not move. Therefore, according to the lighting device 2 of this embodiment, even when the light homogenizing element 50 is swung, the position of the lighting area on each image generation area of the light modulation devices 4R, 4G, and 4B, which is the illuminated area, does not shift. Therefore, according to the projector 1 of this embodiment provided with the lighting device 2, by swinging the first lens array surface 51a conjugate with the screen surface, a high-quality image with less noticeable uneven illuminance can be displayed without degrading the quality of the projected image.

[0058] In the lighting device 2 of this embodiment, by adopting a reflection structure as the diffusion plate 231 of the rotation diffusion device 23 as described above, the polarization disturbance generated in the diffused illumination light WL can be suppressed. Therefore, by reducing the polarization disturbance of the illumination light WL after diffusion, each color light separated from the illumination light WL can be efficiently incident on the image formation areas of the light modulation devices 4R, 4G, and 4B. Therefore, according to the projector 1 using the lighting device 2 of this embodiment, a bright and high-quality image can be projected by efficiently using the illumination light WL from the lighting device 2.

[0059] Note that in the lighting device 2 of the above embodiment, the light homogenizing element 50 is configured by one optical component in which the first lens array surface 51a and the second lens array surface 51b are integrally formed. However, the light homogenizing element may be configured by two optical components, an optical member including a first multi-lens surface and another optical member including a second multi-lens surface.

[0060] (First Modified Example) Hereinafter, as a modified example, another form of the light homogenizing element will be described. The difference between this modified example and the above-described embodiment is that the first multi-lens surface and the second multi-lens surface of the light homogenizing element are composed of two optical members. Therefore, the same reference numerals are given to the configurations common to the above-described embodiment, and the detailed description thereof is omitted.

[0061] FIG. 5 is a diagram showing the configuration of the light homogenizing element of the modified example. As shown in FIG. 5, the light homogenizing element 150 of this modified example includes a first lens array (first optical member) 151, a second lens array (second optical member) 152, and a holding member 155 that holds the first lens array 151 and the second lens array 152.

[0062] The first lens array 151 includes a first lens array surface 153a. The first lens array surface 153a includes a plurality of first small lenses 153 for dividing the illumination light WL into a plurality of partial light beams. The second lens array 152 includes a second lens array surface 154a. The second lens array surface 154a includes a plurality of second small lenses 154 corresponding to the respective first small lenses 153 of the first lens array surface 153a.

[0063] The holding member 155 integrally holds the first lens array 151 and the second lens array 152, and fixes the relative position of the first lens array surface 153a with respect to the second lens array surface 154a. Specifically, the holding member 155 integrally holds the first lens array 151 and the second lens array 152 so that the optical axes of the corresponding first small lenses 153 and second small lenses 154 coincide with each other. Note that, in the light homogenizing element 150 of this modified example, the shapes or the positional relationship between the first lens array surface 153a and the second lens array surface 154a are the same as those of the first lens array surface 51a and the second lens array surface 51b of the light homogenizing element 50 of the above-described embodiment.

[0064] In the case of this modification example, the rocking device 30 is arranged in contact with the holding member 155, and the light homogenizing element 150 is rocked via the holding member 155. The holding member 155 holds the light homogenizing element 150 while restricting the rotation of the light homogenizing element 150 around the Z-axis or the Y-axis.

[0065] Also in the light homogenizing element 150 of this modification example, the rocking device 30 can integrally rock the first lens array surface 153a and the second lens array surface 154a along the X direction and the Z direction orthogonal to the optical axis of the light homogenizing element 150.

[0066] In the above-described embodiment and the first modification example, the illumination device 2 in which the diffused light reflected by the rotation diffusion device 23 is incident on the light homogenizing element 50 is taken as an example. However, the illumination device of the present invention is also applicable to an illumination device in which the light transmitted through the diffusion plate is incident on the light homogenizing element.

[0067] (Second Modification Example) Hereinafter, as a second modification example, another form of the illumination device will be described. The difference between this modification example and the above-described embodiment lies in the peripheral configuration of the diffusion plate in the illumination device, and the other configurations are common. For this reason, the same reference numerals are given to the configurations common to the above-described embodiment, and the detailed description thereof is omitted.

[0068] FIG. 6 is a diagram showing a schematic configuration of the illumination device of this modification example. As shown in FIG. 6, the illumination device 2A of this modification example includes a light source device 20, a condensing element 26, a diffusion plate 61, a collimator element 25, a light homogenizing element 50, a superimposing lens 52, and a rocking device 30.

[0069] In this modification example, the green light source 20G, the photosynthetic member 24, the condensing element 26, the diffusion plate 61, the collimator element 25, the light homogenizing element 50, and the superimposing lens 52 are provided on the optical axis ax2 of the green light source 20G. In this modification example, the optical axis ax2 and the illumination optical axis AX are parallel to each other.

[0070] In this modified example, the condenser element 26 condenses the illumination light WL and makes it incident on the diffusion plate 61. The diffusion plate 61 is disposed on the emission side (+X side) of the condenser element 26. The diffusion plate 61 equalizes the illuminance distribution of the illumination light WL by diffusing the illumination light WL.

[0071] Note that as the diffusion plate 61, a known diffusion plate can be used, for example, ground glass, a holographic diffuser, a transparent substrate with a surface subjected to a blasting process, a transparent substrate with a scattering material such as beads dispersed therein to scatter light by the scattering material, or the like.

[0072] Also in the lighting device 2A of this modified example, unevenness in illuminance due to light interference can be reduced by oscillating the light uniformity element 50 with the oscillating device 30.

[0073] (Third Modified Example) Hereinafter, as a third modified example, another form of the lighting device will be described. The difference between this modified example and the above-described embodiment lies in the configuration of the lighting device, and the other configurations are common. For this reason, the same reference numerals are given to the configurations common to the above-described embodiment, and the detailed description thereof is omitted.

[0074] FIG. 7 is a diagram showing a schematic configuration of the lighting device of this modified example. As shown in FIG. 7, the lighting device 2B of this modified example includes a light source device 20, a condenser element 26, a diffusion plate 61, a collimator element 25, a light uniformity element 50, a superimposing lens 52, an oscillating device 30, and a polarization conversion element 70. That is, the lighting device 2B of this modified example is different from the lighting device 2 of the above-described embodiment in that it includes a polarization conversion element 70 disposed between the light uniformity element 50 and the superimposing lens 52.

[0075] The polarization conversion element 70 is an element that aligns the light emitted from the light uniformity element 50 in a predetermined polarization direction. The polarization conversion element 70 has a plurality of polarization separation layers 71, a plurality of reflection layers 72, a plurality of retardation layers 73, and a light shielding film 74. The phase difference layer 73 is provided on the light emission side of the polarization conversion element 70. The polarization conversion element 70 includes a plurality of incident apertures 70K through which the light emitted from the light homogenizing element 50 passes. In the Y direction, each incident aperture 70K is provided corresponding to each second small lens 54 on the second lens array surface 51b of the light homogenizing element 50. Each incident aperture 70K is constituted by an aperture formed in a light shielding film 74 disposed on the light incident surface side of the polarization conversion element 70.

[0076] In this modified example, the polarization conversion element 70 and the light homogenizing element 50 are housed in a holder 55. The swinging device 30 is disposed in contact with the holder 55 and swings the polarization conversion element 70 together with the light homogenizing element 50 via the holder 55.

[0077] According to the lighting device 2B of this modified example, unevenness in illuminance due to light interference can be reduced by swinging the light homogenizing element 50 by the swinging device 30. In the case of this modified example, when the light homogenizing element 50 is swung by the swinging device 30, since the polarization conversion element 70 swings together with the light homogenizing element 50, the positional relationship between each second small lens 54 on the second lens array surface 51b and each incident aperture 70K of the polarization conversion element 70 can be made constant.

[0078] Therefore, even when the swinging device 30 swings the polarization conversion element 70 together with the light homogenizing element 50, the lighting device 2B of this modified example can efficiently transmit the red illumination light R, the green illumination light G, and the blue illumination light B separated from the illumination light WL through the polarizing plates disposed on the incident sides of the respective light modulation devices 4R, 4G, 4B by aligning the polarization direction of the illumination light WL in one direction. Thus, the lighting device 2B of this modified example can further improve the light utilization efficiency of the illumination light WL.

[0079] In this modified example, the case where the polarization conversion element 70 is swung together with the light homogenizing element 50 has been taken as an example. However, a configuration may be adopted in which only the light homogenizing element 50 is swung without swinging the polarization conversion element. When only the light homogenizing element 50 is swung, as the polarization conversion element, it is preferable to use a structure in which each incident aperture corresponds to a plurality of second small lenses 54 in the light homogenizing element 50. By using a polarization conversion element having such a structure, even when only the light homogenizing element 50 is swung, the light emitted from the second small lenses 54 of the light homogenizing element 50 can be satisfactorily taken into the polarization conversion element.

[0080] Note that the technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Regarding the specific descriptions of the shapes, numbers, arrangements, materials, etc. of the respective components of the lighting device and the projector shown in the above embodiments, the descriptions are not limited to the above embodiments, and can be appropriately changed.

[0081] For example, in the lighting devices of the above embodiments and modified examples, the case where light synthesized from three color lights is emitted as illumination light has been taken as an example. However, the present invention may be applied to a lighting device that emits monochromatic illumination light. In a monochromatic lighting device, the light homogenizing element into which the light emitted from one light source is incident is swung, and it is possible to reduce the unevenness of the illuminance of the illumination light emitted from the light homogenizing element via the superimposing lens. Further, such a monochromatic lighting device may be applied to a projector that uses only one light modulation device. Also, in the lighting devices of the above embodiments and modified examples, the case where a diffusion plate is used has been taken as an example. However, a configuration may be adopted in which the light homogenizing element is swung without using a diffusion plate. According to this configuration, it is conceivable that the unevenness of the illuminance in the illuminated area becomes more prominent because the light scattering effect by the diffusion plate is eliminated. However, according to the present invention, the unevenness of the illuminance can be made less prominent by swinging the light homogenizing element. That is, the effect of the present invention can be made more remarkable by omitting the diffusion plate. In the above-described embodiments and modifications, an example in which the light source device according to the present invention is mounted on a projector using a liquid crystal panel has been shown, but the present invention is not limited to this. The light source device according to the present invention may be applied to a projector using a digital micromirror device as a light modulation device.

[0082] In the above-described embodiment, an example in which the lighting device of the present invention is applied to a projector has been shown, but the present invention is not limited to this. The lighting device of the present invention can also be applied to lighting fixtures, headlamps of automobiles, and the like.

[0083] Hereinafter, a summary of the present disclosure will be appended. (Appendix 1) A first light source that emits first light in a first wavelength band, A second light source that emits second light in a second wavelength band different from the first wavelength band, A light combining member that combines the first light and the second light to emit combined light, A light homogenizing element having a first lens array surface on which the combined light is incident and a second lens array surface that emits light that has passed through the first lens array surface, and the first lens array surface and the second lens array surface are integrated, A swinging device that swings the light homogenizing element, A superimposing lens that superimposes the light emitted from the light homogenizing element, Comprising A lighting device characterized by the above.

[0084] According to the lighting device having this configuration, by integrally swinging the first lens array surface and the second lens array surface by the swinging device, it is possible to make it difficult to recognize unevenness in the illuminance of the illumination light that illuminates the illuminated area, as if the illuminated area of the lighting device is swung.

[0085] (Appendix 2) The swinging device integrally swings the first lens array surface and the second lens array surface along a direction orthogonal to the optical axis of the light homogenizing element. The lighting device according to Appendix 1, characterized by the above.

[0086] According to this configuration, by integrally swinging the swing device in a direction perpendicular to the optical axis of the first lens array surface and the second lens array surface, unevenness in illuminance can be made less noticeable.

[0087] (Appendix 3) The swing device integrally swings the first lens array surface and the second lens array surface along a first direction perpendicular to the optical axis of the light homogenizing element and a second direction perpendicular to the optical axis and the first direction. The lighting device according to Appendix 1 or Appendix 2, characterized in that.

[0088] According to this configuration, by integrally swinging the swing device in two directions for the first lens array surface and the second lens array surface, unevenness in illuminance can be made even less noticeable.

[0089] (Appendix 4) The first lens array surface and the second lens array surface are one optical component integrally formed, The swing device swings the optical component. The lighting device according to any one of Appendices 1 to 3, characterized in that.

[0090] According to this configuration, by swinging a light homogenizing element composed of one optical member in which the first lens array surface and the second lens array surface are integrally formed, unevenness in illuminance of the combined light can be reduced.

[0091] (Appendix 5) Further provided is a holding member that integrally holds a first optical member including the first lens array surface and a second optical member including the second lens array surface, and fixes the relative position of the first lens array surface with respect to the second lens array surface. The swing device swings the holding member. The lighting device according to any one of Appendices 1 to 4, characterized in that.

[0092] According to this configuration, by oscillating a light homogenizing element in which the first lens array surface and the second lens array surface are formed of separate optical members, it is possible to reduce the illuminance unevenness of the combined light.

[0093] (Appendix 6) Further comprising a polarization conversion element disposed between the light homogenizing element and the superimposing lens, for aligning the light emitted from the light homogenizing element in a predetermined polarization direction. The lighting device according to any one of Appendices 1 to 5, characterized in that.

[0094] According to this configuration, the polarization direction of the combined light can be aligned in a predetermined polarization direction.

[0095] (Appendix 7) The oscillating device oscillates the polarization conversion element together with the light homogenizing element. The lighting device according to Appendix 6, characterized in that.

[0096] According to this configuration, since the light homogenizing element and the polarization conversion element oscillate integrally, the light emitted from the light homogenizing element can be efficiently incident on the polarization conversion element.

[0097] (Appendix 8) A diffusion plate for diffusing the combined light incident from the light synthesizing member, Further comprising a collimator element for collimating the combined light emitted from the diffusion plate. The lighting device according to any one of Appendices 1 to 7, characterized in that.

[0098] According to this configuration, by diffusing the combined light, it is possible to enhance the uniformity of the illuminance distribution and make the illuminance unevenness less noticeable. Also, by collimating the light diffused by the diffusion plate, it is possible to suppress an increase in the size of the light homogenizing element.

[0099] (Appendix 9) The frequency of the oscillation generated by the oscillating device is 60 Hz or more and 500 Hz or less. The lighting device according to any one of Appendices 1 to 8, characterized in that...

[0100] According to this configuration, it is possible to efficiently reduce the illuminance unevenness while suppressing the cost of the swinging device.

[0101] (Appendix 10) Further comprising a third light source that emits third light in a third wavelength band different from the first wavelength band and the second wavelength band, The photosynthetic member emits the combined light obtained by combining the third light with the first light and the second light, The lighting device according to any one of Appendices 1 to 9, characterized in that...

[0102] According to this configuration, it is possible to reduce the speckle noise of the combined light including three color lights.

[0103] (Appendix 11) The first light source and the second light source are laser light sources, The lighting device according to any one of Appendices 1 to 10, characterized in that...

[0104] According to this configuration, since interference of light is likely to occur by using laser light as illumination light, the effect of reducing the illuminance unevenness due to the interference of light according to the present invention can be obtained more remarkably.

[0105] (Appendix 12) A lighting device according to any one of Appendices 1 to 11, An optical modulation device that modulates the light emitted from the lighting device, A projection optical device that projects the light modulated by the optical modulation device, comprising: The first lens array surface is optically conjugate to an image generation region that generates an image in the optical modulation device, A projector characterized in that...

[0106] According to the projector of this configuration, by swinging the first lens array surface conjugate with the projection surface, a high-quality image with suppressed illuminance unevenness and speckle noise can be displayed without degrading the quality of the projected image.

Explanation of Signs

[0107] 1…Projector, 2, 2A, 2B…Illumination device, 4B, 4G, 4R…Light modulation device, 6…Projection optical device, 20B…Blue light source (third light source), 20G…Green light source (second light source), 20R…Red light source (first light source), 61, 231…Diffusion plate, 24…Light combining member, 25…Collimator element, 30…Swinging device, 70…Polarization conversion element, 50, 150…Light homogenizing element, 51a, 153a…First lens array surface, 51b, 154a…Second lens array surface, 52…Superposition lens, 151…First lens array (first optical member), 152…Second lens array (second optical member), 155…Holding member, ax1, ax2…Optical axis.

Claims

1. A first light source that emits first light in a first wavelength band, A second light source that emits second light in a second wavelength band different from the first wavelength band, A light combining member that combines the first light and the second light to emit combined light, A light homogenizing element having a first lens array surface on which the combined light is incident and a second lens array surface that emits light that has passed through the first lens array surface, and the first lens array surface and the second lens array surface are integrated, A rocking device that rocks the light homogenizing element, A superimposing lens that superimposes the light emitted from the light homogenizing element, Comprising: An illumination device characterized by the above.

2. The rocking device integrally rocks the first lens array surface and the second lens array surface along a direction orthogonal to the optical axis of the light homogenizing element. The illumination device according to claim 1, characterized by the above.

3. The rocking device integrally rocks the first lens array surface and the second lens array surface along a first direction orthogonal to the optical axis of the light homogenizing element and a second direction orthogonal to the optical axis and the first direction. The illumination device according to claim 1, characterized by the above.

4. The first lens array surface and the second lens array surface are one optical component integrally formed, The rocking device rocks the optical component. The illumination device according to any one of claims 1 to 3, characterized by the above.

5. Further comprising a holding member that integrally holds a first optical member including the first lens array surface and a second optical member including the second lens array surface, and fixes the relative position of the first lens array surface with respect to the second lens array surface, The rocking device rocks the holding member. The illumination device according to any one of claims 1 to 3, characterized by the above.

6. Further comprising a polarization conversion element disposed between the light homogenizing element and the superimposing lens, and aligning the light emitted from the light homogenizing element in a predetermined polarization direction. The illumination device according to any one of claims 1 to 3, characterized by the above.

7. The rocking device rocks the polarization conversion element together with the light homogenizing element. The illumination device according to claim 6, characterized by the above.

8. A diffuser plate that diffuses the combined light incident from the light combining member, Further comprising a collimator element that collimates the combined light emitted from the diffuser plate. The lighting device according to any one of claims 1 to 3, characterized in that...

9. The frequency of the oscillation generated by the oscillation device is 60 Hz or more and 500 Hz or less. The lighting device according to any one of claims 1 to 3, characterized in that...

10. The lighting device further comprises a third light source that emits third light in a third wavelength band different from the first wavelength band and the second wavelength band. The photosynthetic member emits the combined light obtained by combining the third light with the first light and the second light. The lighting device according to any one of claims 1 to 3, characterized in that...

11. The first light source and the second light source are laser light sources. The lighting device according to any one of claims 1 to 3, characterized in that...

12. A lighting device according to any one of claims 1 to 3, An optical modulation device that modulates the light emitted from the lighting device, A projection optical device that projects the light modulated by the optical modulation device, and comprises: The first lens array surface is in an optically conjugate relationship with an image generation region that generates an image in the optical modulation device. A projector, characterized in that...

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