Illumination device and projector

Abstract

The invention provides an illumination device and a projector, which can reduce illumination unevenness caused by light interference. An illumination device is provided with: a first light source that emits first light of a first wavelength band; a second light source that emits second light of a second wavelength band; a light combining member that combines the first light and the second light and emits combined light; a diffusion device provided with a substrate having a diffusion surface that diffuses and emits the synthesized light, and a drive device that rotates the substrate; a light-condensing element that is disposed between the light-synthesizing member and the diffusion device and that condenses the synthesized light toward the diffusion device; a collimating element that parallelizes the combined light emitted from the diffusion device; a light uniformizing element having a first lens array surface on which the combined light from the collimator lens is incident and a second lens array surface from which the light incident from the first lens array surface is emitted, the first lens array surface and the second lens array surface being integrated; a swinging device that swings the light homogenizing element; and an overlapping lens that overlaps the light emitted from the light homogenizing element.

Description

Technical Field

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

[0002] For the purpose of high performance of a projector, a projector equipped with a lighting device using a laser light source, which is a wide color gamut and high-efficiency light source, has been proposed. A lighting device having 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 is disclosed in Patent Document 1 below.

[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-78906

[0004] In the above lighting device, since a plurality of lenses are regularly arranged in the multi-lens array, sometimes diffracted light generated between the lights extended in each lens or between adjacent lenses overlaps to cause interference. Therefore, in the projected image of the above projector, there is a problem of uneven illuminance due to light interference. Summary of the Invention

[0005] In order to solve the above problems, according to one aspect of the present invention, there is provided a lighting 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 synthesis component that synthesizes the first light and the second light and emits synthesized light; a light homogenizing element having a first lens array surface on which the synthesized light is incident and a second lens array surface that emits light after passing through the first lens array surface, the first lens array surface and the second lens array surface being integrated; a swing device that swings the light homogenizing element; and an overlapping lens that overlaps 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 lighting device according to the above aspect; a light modulation device that modulates the light emitted from the lighting device; and a projection optical device that projects the light modulated by the light modulation device. Brief Description of the Drawings

[0007] Figure 1 is a schematic structural diagram of a projector.

[0008] Figure 2 is a diagram showing a schematic structure of a lighting device.

[0009] Figure 3 is a diagram showing the structure of a light homogenizing element.

[0010] Figure 4 is a diagram showing the structure of a swing device.

[0011] Figure 5 This is a diagram showing the structure of the light homogenizing element according to the first modification example.

[0012] Figure 6 This is a diagram showing the schematic structure of the lighting device according to the second modification example.

[0013] Figure 7 This is a diagram showing the schematic structure of the lighting device according to the third modification example.

[0014] Reference Numeral Explanation

[0015] 1: Projector; 2, 2A, 2B: Lighting 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: Collimating element; 30: Swing device; 70: Polarization conversion element; 50, 150: Light homogenizing element; 51a, 153a: First lens array surface; 51b, 154a: Second lens array surface; 52: Overlapping lens; 151: First lens array (first optical component); 152: Second lens array (second optical component); 155: Holding member; ax1, ax2: Optical axis. Detailed Description of the Embodiment

[0016] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In addition, in the drawings used in the following description, in order to easily understand the features, the portions that become the features are sometimes enlarged for convenience, and the dimensional ratios of the respective components are not necessarily the same as the actual ones.

[0017] Hereinafter, an embodiment of the present invention will be described.

[0018] Figure 1 This is a schematic structural diagram of a projector according to an embodiment.

[0019] As Figure 1 shown, the projector 1 of the present embodiment is a projection type image display device that displays an image on the screen SCR. The projector 1 includes a lighting device 2, a color separation optical system 3, a light modulation device 4R, a light modulation device 4G, a light modulation device 4B, a combining optical system 5, and a projection optical device 6.

[0020] The lighting device 2 emits white illumination light WL toward the color separation optical system 3. The structure of the lighting device 2 will be described in detail later.

[0021] 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, a first relay lens 9a, and a second relay lens 9b. Hereinafter, red, green, and blue may also be collectively referred to as RGB colors.

[0022] 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.

[0023] The total reflection mirror 8a reflects the red illumination light R toward the light modulation device 4R. The total reflection mirror 8b and the total reflection mirror 8c guide the blue illumination light B to the light modulation device 4B. The green illumination light G is reflected from the dichroic mirror 7b toward the light modulation device 4G.

[0024] 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.

[0025] The light modulation device 4R modulates the red illumination light R according to the image information to form red image light. The light modulation device 4G modulates the green illumination light G according to the image information to form green image light. The light modulation device 4B modulates the blue illumination light B according to the image information to form blue image light.

[0026] The light modulation device 4R, the light modulation device 4G, and the light modulation device 4B use, for example, transmissive liquid crystal panels. In addition, polarizing plates (not shown) are respectively arranged on the incident side and the emission side of the liquid crystal panel.

[0027] And field lenses 10R, 10G, and 10B are respectively arranged on the incident sides of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B.

[0028] The respective image lights from the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B are incident on the synthesis optical system 5. The synthesis optical system 5 synthesizes the respective image lights and emits the synthesized image light toward the projection optical device 6. The synthesis optical system 5 uses, for example, a cross dichroic prism.

[0029] The projection optical device 6 is composed of a projection lens group and magnifies and projects the image light synthesized by the synthesis optical system 5 onto the screen SCR. Thus, an enlarged color image is displayed on the screen SCR.

[0030] Next, the illumination device 2 according to an embodiment of the present invention will be described. Figure 2This is a diagram showing the schematic structure of the lighting device 2.

[0031] As Figure 2 shown, the lighting device 2 includes a light source device 20, a condenser element 26, a rotary diffusion device 23, a collimating element 25, a light homogenizing element 50, an overlapping lens 52, and a swing device 30.

[0032] The light source device 20 includes a red light source (first light source) 20R for red, a green light source (second light source) 20G for green, a blue light source (third light source) 20B for blue, and a light combining member 24.

[0033] In the present embodiment, the red light source 20R, the light combining member 24, and the blue light source 20B are disposed 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 disposed on the optical axis ax2 of the green light source 20G. In addition, the rotary diffusion device 23, the collimating element 25, the light homogenizing element 50, and the overlapping lens 52 are disposed on the illumination optical axis AX of the lighting device 2. Further, 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. And, 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.

[0034] Hereinafter, when describing the shape and arrangement of the components of the lighting device 2, an XYZ coordinate system may also 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.

[0035] The red light source 20R includes a plurality of red semiconductor lasers 21R and a plurality of collimating lenses 22R. The green light source 20G includes a plurality of green semiconductor lasers 21G and a plurality of collimating lenses 22G. The blue light source 20B includes a plurality of blue semiconductor lasers 21B and a plurality of collimating lenses 22B.

[0036] That is, each of the light sources 20R, 20G, 20B is a laser light source.

[0037] 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 red light Br in a first wavelength band of, for example, 585 nm to 720 nm. The plurality of collimating lenses 22R are respectively arranged corresponding to the plurality of red semiconductor lasers 21R, and convert the red light Br emitted from the corresponding laser into parallel light.

[0038] Based on such a structure, a red light source 20R emits a red light LR containing a plurality of red light rays Br formed by parallel light beams toward the photosynthesis component 24.

[0039] A 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 green light rays Bg in a second wavelength band different from the first wavelength band, for example, in the range of 495 nm to 585 nm. A plurality of collimating lenses 22G are respectively arranged corresponding to the plurality of green semiconductor lasers 21G, and convert the green light rays Bg emitted from the corresponding lasers into parallel light.

[0040] Based on such a structure, a green light source 20G emits a green light LG containing a plurality of green light rays Bg formed by parallel light beams toward the photosynthesis component 24.

[0041] A 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 blue light rays Bb in a third wavelength band different from the first and second wavelength bands, for example, in the range of 380 nm to 495 nm. A plurality of collimating lenses 22B are respectively arranged corresponding to the plurality of blue semiconductor lasers 21B, and convert the blue light rays Bb emitted from the corresponding lasers into parallel light.

[0042] Based on such a structure, a blue light source 20B emits a blue light LB containing a plurality of blue light rays Bb formed by parallel light beams toward the photosynthesis component 24.

[0043] The photosynthesis component 24 emits white illumination light WL obtained by synthesizing RGB-colored lights (red light LR, green light LG, and blue light LB) emitted from the light source device 20 in one direction, and makes it incident on the condenser element 26. The condenser element 26 converges the illumination light WL at a predetermined position.

[0044] The photosynthesis component 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 arranged to cross each other at 45° with respect to the optical axis ax1 and the optical axis ax2, respectively. In addition, the first dichroic mirror 24a and the second dichroic mirror 24b cross each other at an angle of 45°.

[0045] The first dichroic mirror 24a has an optical characteristic of reflecting the blue light LB and transmitting the green light LG and the red light LR. The second dichroic mirror 24b has an optical characteristic of reflecting the red light LR and transmitting the blue light LB and the green light LG.

[0046] The condenser element 26 condenses and makes the illumination light WL incident on the rotary diffusion device 23. The rotary diffusion device 23 diffuses the illumination light WL to equalize the illuminance distribution of the illumination light WL. The rotary diffusion device 23 includes a diffusion plate 231 that can rotate about a specified rotation axis and a drive device 232 composed of a motor. The diffusion plate 231 is formed, for example, by forming an uneven structure on the surface of a circular plate made of a metal such as aluminum by using an etching process, a sandblasting process, or the like. The rotary diffusion device 23 is arranged to intersect the optical axis ax2 and the illumination optical axis AX at 45°.

[0047] The collimating element 25 collimates the illumination light WL emitted from the rotary diffusion device 23 and emits it toward the light equalizing element 50. In the case of the present embodiment, the collimating element 25 is composed of a single convex lens. Alternatively, the collimating element 25 may be composed of a plurality of lenses.

[0048] The light equalizing element 50, together with the overlapping lens 52, equalizes the illuminance distribution of the illumination light WL emitted from the collimating element 25 in the image generation regions of the light modulation devices 4R, 4G, and 4B.

[0049] The light equalizing element 50 of the present embodiment is composed of a double-sided multi-lens array in which a first lens array surface 51a and a second lens array surface 51b are integrated. That is, the light equalizing element 50 of the present embodiment is composed of a single optical component in which the first lens array surface 51a and the second lens array surface 51b are integrally formed.

[0050] In addition, the pitch of the multi-lens array constituting the light equalizing element 50 of the present embodiment is preferably set, for example, to 0.1 mm or more and 1 mm or less. Thereby, the light equalizing element 50 is composed of a narrow-pitch micro-lens array unit, and by increasing the number of light source images overlapping the illuminated region, the light equalizing performance can be improved.

[0051] The first lens array surface 51a is the surface on which the illumination light WL emitted from the collimating 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.

[0052] The second lens array surface 51b is a surface that emits a plurality of partial light beams divided by 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 and the subsequent overlapping lens 52 image the images of the respective first small lenses 53 of the first lens array surface 51a in or near the image generation regions of the light modulation devices 4R, 4G, and 4B. The plurality of second small lenses 54 are arranged in a matrix in a plane orthogonal to the illumination optical axis AX.

[0053] The overlapping lens 52 converges the plurality of partial light beams emitted from the light homogenizing element 50 and overlaps them with each other in or near the image generation regions of the light modulation devices 4R, 4G, and 4B.

[0054] The light homogenizing element 50 is accommodated in the 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 swing device 30 is configured to be in contact with the holder 55 and swing the light homogenizing element 50 via the holder 55. The holder 55 of the present embodiment holds the light homogenizing element 50 in a state where rotation of the light homogenizing element 50 about the Z axis or about the X axis is restricted.

[0055] The swing device 30 swings the first lens array surface 51a and the second lens array surface 51b integrally in a direction orthogonal to the optical axis of the light homogenizing element 50. Here, the integral swing of the first lens array surface 51a and the second lens array surface 51b 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 swing device 30.

[0056] More specifically, the swing device 30 swings the first lens array surface 51a and the second lens array surface 51b integrally in the X direction (first direction) orthogonal to the optical axis of the light homogenizing element 50 and in the Z direction (second direction) orthogonal to the optical axis and the X direction. The light homogenizing element 50 swings in a state where rotation about the Z axis or about the X axis is suppressed by the holder 55.

[0057] Here, in the projector 1 of the present embodiment, the first lens array surface 51a of the light homogenizing element 50 and the image generation regions where images are generated in the respective light modulation devices 4R, 4G, and 4B are in an optically conjugate relationship. Therefore, the shapes of the respective first small lenses 53 of the first lens array surface 51a have a rectangular shape that is substantially similar to the shapes of the image generation regions of the light modulation devices 4R, 4G, and 4B.

[0058] On the other hand, the screen surface that projects the image light generated by each image generation region of the light modulation devices 4R, 4G, and 4B and the respective image generation regions of the light modulation devices 4R, 4G, and 4B have an optically conjugate relationship. That is, it can be said that the first lens array surface 51a having a conjugate relationship with the image generation region is indirectly conjugate to the screen surface.

[0059] In the projector 1 of the present embodiment, by swinging the first lens array surface 51a of the light homogenizing element 50 that is conjugate to the screen surface, it is possible to make it difficult to visually recognize the uneven illuminance of the projected image as will be described later.

[0060] The frequency of the swing generated by the swing device 30 is preferably 60 Hz or more and 500 Hz or less.

[0061] This is because if the frequency is less than 60 Hz, the projected image flickers. In addition, if the frequency is higher than 500 Hz, it is necessary to further improve the firmness of the swing device 30 itself and the device main body of the illumination device that houses the swing device 30, which causes an increase in cost.

[0062] 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, it is possible to achieve a structure that suppresses flicker and reduces uneven illuminance at low cost.

[0063] In addition, the amplitude of the light homogenizing element 50 caused by the swing device 30 is, for example, 150 μm. Furthermore, the amplitude of the light homogenizing element 50 is not limited to the above value and can be appropriately adjusted according to the pitch of the lens array surface and the period of the interference fringes that cause uneven illuminance.

[0064] Figure 3 It is a diagram showing the structure of the light homogenizing element 50.

[0065] As Figure 3 shown, the foci P1 of the respective second small lenses 54 in the second lens array surface 51b are arranged on the light incident surfaces 53a of the corresponding first small lenses 53 among the plurality of first small lenses 53. Therefore, 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.

[0066] In addition, the foci P2 of the respective first small lenses 53 on the first lens array surface 51a are arranged on the light emission surfaces 54a of the corresponding second small lenses 54 among the plurality of second small lenses 54. Therefore, the partial light beams divided by the first small lens 53 converge on the light emission surfaces 54a of the respective second small lenses 54. Therefore, the second small lens 54 can efficiently take in the light from the first small lens 53 and emit it. Therefore, the light loss in the light homogenizing element 50 can be reduced.

[0067] Figure 4 This is a diagram showing an example of the structure of the swing device 30.

[0068] As Figure 4 shown, the swing device 30 includes: a housing main body 31 that includes a contact portion 36 that contacts the light homogenizing element 50; a motor 32 that includes a shaft portion 33 that rotates about a rotation axis O; a rotating member 34 that is provided on the shaft portion 33 of the motor 32; and a bearing 37 that supports the rotating member 34 so as to be rotatable. Further, the rotation axis O is an imaginary axis that passes through the center of the shaft portion 33.

[0069] The housing main 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 a weight 35 that is eccentric with respect to the rotation axis O is included in the central portion. Here, the weight 35 that is eccentric with respect to the rotation axis O means a state in which the center of gravity of the weight 35 is offset in a direction orthogonal to the rotation axis O.

[0070] The swing device 30 rotates the rotating member 34 together with the shaft portion 33 of the motor 32. At this time, since the center of gravity of the weight 35 rotates while being offset from the rotation axis O, the motor 32 itself is swung by the weight 35 and vibrates. The vibration of the motor 32 is transmitted to the housing main body 31, and the light homogenizing element 50 is swung via the contact portion 36.

[0071] According to the swing device 30 of the present embodiment, by means of a simple structure in which a weight 35 that is eccentric with respect to the rotation axis O is provided on the rotating member 34 that rotates together with the shaft portion 33 of the motor 32, it is possible to realize a structure in which the light homogenizing element 50 is swung at low cost without increasing the size of the device structure.

[0072] 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 component 24 that combines the red light LR, the green light LG, and the blue light LB and emits 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 component 24 and the rotary diffusing device 23 and converges the illumination light WL toward the rotary diffusing device 23; a collimating element 25 that collimates the illumination light WL emitted from the rotary diffusing device 23; a light homogenizing element 50 that has a first lens array surface 51a on which the illumination light WL emitted from the collimating element 25 is incident and a second lens array surface 51b that emits the light after passing through the first lens array surface 51a, and the first lens array surface 51a and the second lens array surface 51b are integrated; a swinging device 30 that swings the light homogenizing element 50; and an overlapping lens 52 that overlaps the light emitted from the light homogenizing element 50.

[0073] Here, the first lens array surface 51a of the light homogenizing element 50 has a structure in which a plurality of first microlenses 53 are regularly arranged as described above. Therefore, in the first lens array surface 51a, the light divided by the plurality of first microlenses 53 or the diffracted light generated between the ridges between adjacent first microlenses 53 may overlap with each other and cause interference.

[0074] In the case of the present embodiment, the colored lights LR, LG, LB included in the illumination light WL are coherent lights, so 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 linear or striped illuminance unevenness due to light interference in each image generation region of the light modulation devices 4R, 4G, 4B in an optically conjugate relationship and on the screen surface. Such illuminance unevenness may cause a reduction in the visibility of the projected image. In addition, the shape and interval of the stripes or unevenness caused by light interference vary depending on, for example, the shape of the first microlens 53 or the interval of the ridges.

[0075] In contrast, the lighting device 2 of the present embodiment swings the first lens array surface 51a conjugate to the screen SCR by using the swinging device 30, and can achieve the same effect as swinging the screen SCR on which an image is projected in appearance. That is, similarly to the case of swinging the screen SCR, the illuminance unevenness of the projected images based on the colored lights LR, LG, LB changes over time on the screen SCR. As a result, the viewer of the projector 1 visually confirms the lines and stripes after time averaging, so that the viewer can hardly visually confirm the illuminance unevenness.

[0076] In addition, in the lighting device 2 of the present embodiment, since the respective color lights LR, LG, and LB included in the illumination light WL are coherent lights, speckle may be generated in the projected image. In contrast, in the lighting device 2 of the present embodiment, by swinging the first lens array surface 51a conjugate to the screen SCR using the swinging device 30, it is also possible to reduce the speckle noise of the projected image.

[0077] In addition, in the lighting device 2 of the present embodiment, as described above, the focal point P1 of the second small lens 54 is located on the light incident surface 53a of the first small lens 53. Therefore, 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 overlapping lens 52.

[0078] In addition, in the case of the present embodiment, when the light homogenizing element 50 is swung, rotation of the light homogenizing element 50 about the Z axis or about the Y axis is restricted. Therefore, the light emitted as parallel light from the second lens array surface 51b is incident on the overlapping lens 52 at a predetermined angle.

[0079] In this way, in the lighting device 2 of the present embodiment, even when the light homogenizing element 50 is swung, the incident angle of the light from the light homogenizing element 50 in the overlapping lens 52 does not change. Therefore, the illumination area of the overlapping lens 52, that is, the illumination area on the image generation area of each of the light modulation devices 4R, 4G, and 4B does not move.

[0080] Therefore, according to the lighting device 2 of the present embodiment, even when the light homogenizing element 50 is swung, the position of the illumination area on the image generation area of each of the light modulation devices 4R, 4G, and 4B serving as the illuminated area does not shift.

[0081] Therefore, according to the projector 1 of the present embodiment having the lighting device 2, the quality of the projected image is not degraded, and by swinging the first lens array surface 51a conjugate to the screen surface, it is possible to display a high-quality image with less noticeable illuminance unevenness.

[0082] In the lighting device 2 of the present embodiment, by adopting the reflection structure as the diffusion plate 231 of the rotational diffusion device 23 as described above, it is possible to suppress the disturbance of polarization generated in the diffused illumination light WL. Therefore, by reducing the disturbance of polarization of the diffused illumination light WL, it is possible to efficiently make the respective color lights obtained by separating the illumination light WL 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 the present embodiment, by efficiently using the illumination light WL from the lighting device 2, it is possible to project a bright and high-quality image.

[0083] In addition, in the lighting device 2 of the above-described embodiment, the light homogenizing element 50 is constituted by one optical component integrally formed by the first lens array surface 51a and the second lens array surface 51b. However, the light homogenizing element may also be constituted by two optical components, namely, an optical component including the first multi-lens surface and another optical component including the second multi-lens surface.

[0084] First Modification

[0085] Hereinafter, as a modification, other embodiments of the light homogenizing element will be described. The difference between this modification and the above-described embodiment is that the first multi-lens surface and the second multi-lens surface of the light homogenizing element are constituted by two optical components. Therefore, the same reference numerals are assigned to the same structures as those in the above-described embodiment, and detailed descriptions thereof are omitted.

[0086] Figure 5 FIG. is a diagram showing the structure of the light homogenizing element of the modification.

[0087] As Figure 5 shown, the light homogenizing element 150 of this modification includes a first lens array (first optical component) 151, a second lens array (second optical component) 152, and a holding member 155 that holds the first lens array 151 and the second lens array 152.

[0088] 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.

[0089] 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 such that the optical axes of the corresponding first small lenses 153 and second small lenses 154 are aligned.

[0090] In addition, in the light homogenizing element 150 of this modification, 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 in the above-described embodiment.

[0091] In the case of this modification example, the swing device 30 is arranged in a state of being in contact with the holding member 155, and causes the light homogenizing element 150 to swing via the holding member 155. The holding member 155 holds the light homogenizing element 150 in a state where rotation of the light homogenizing element 150 about the Z axis or about the Y axis is restricted.

[0092] In the light homogenizing element 150 of this modification example, the first lens array surface 153a and the second lens array surface 154a can also be integrally swung in the X direction and the Z direction orthogonal to the optical axis of the light homogenizing element 150 by the swing device 30.

[0093] 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 exemplified, but the illumination device of the present invention can also be applied to an illumination device in which the light transmitted through the diffusion plate is incident on the light homogenizing element.

[0094] Second Modification Example

[0095] Hereinafter, as the second modification example, another mode of the illumination device will be described.

[0096] The difference between this modification example and the above-described embodiment lies in the peripheral structure of the diffusion plate in the illumination device, and the other structures are the same. Therefore, the same reference numerals are given to the same structures as those in the above-described embodiment, and the detailed description thereof is omitted.

[0097] Figure 6 It is a diagram showing a schematic structure of the illumination device of this modification example.

[0098] As Figure 6 shown, the illumination device 2A of this modification example includes a light source device 20, a condenser element 26, a diffusion plate 61, a collimating element 25, a light homogenizing element 50, an overlapping lens 52, and a swing device 30.

[0099] In this modification example, the green light source 20G, the photosynthetic member 24, the condenser element 26, the diffusion plate 61, the collimating element 25, the light homogenizing element 50, and the overlapping lens 52 are provided on the optical axis ax2 of the green light source 20G. In this modification example, the optical axis ax2 is parallel to the illumination optical axis AX.

[0100] In this modification example, the condenser element 26 converges 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 diffuses the illumination light WL to make the illuminance distribution of the illumination light WL uniform.

[0101] In addition, as the diffusion plate 61, a known diffusion plate can be used, such as frosted glass, a holographic diffuser, a diffusion plate obtained by subjecting the surface of a transparent substrate to sandblasting, a diffusion plate in which scattering materials such as microbeads are dispersed inside a transparent substrate and light is scattered by the scattering materials, and the like.

[0102] In the lighting device 2A of this modification, by swinging the light homogenizing element 50 using the swinging device 30, it is also possible to reduce the uneven illuminance caused by light interference.

[0103] Third modification

[0104] Hereinafter, as a third modification, another mode of the lighting device will be described.

[0105] The difference between this modification and the above-described embodiment lies in the structure in the lighting device, and the other structures are the same. Therefore, the same reference numerals are assigned to the same structures as those in the above-described embodiment, and detailed descriptions thereof are omitted.

[0106] Figure 7 It is a diagram showing a schematic structure of the lighting device of this modification.

[0107] As Figure 7 shown, the lighting device 2B of this modification includes a light source device 20, a condensing element 26, a diffusion plate 61, a collimating element 25, a light homogenizing element 50, an overlapping lens 52, a swinging device 30, and a polarization conversion element 70. That is, the difference between the lighting device 2B of this modification and the lighting device 2 of the above-described embodiment is that a polarization conversion element 70 is provided between the light homogenizing element 50 and the overlapping lens 52.

[0108] The polarization conversion element 70 is an element that makes the light emitted from the light homogenizing element 50 coincide with a specified polarization direction. The polarization conversion element 70 includes 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.

[0109] The retardation layer 73 is provided on the light emitting side of the polarization conversion element 70. The polarization conversion element 70 includes a plurality of incident openings 70K through which the light emitted from the light homogenizing element 50 passes. In the Y direction, each incident opening 70K is provided corresponding to each second small lens 54 in the second lens array surface 51b of the light homogenizing element 50. Each incident opening 70K is formed by an opening formed in the light shielding film 74 disposed on the light incident surface side of the polarization conversion element 70.

[0110] In this modification, the polarization conversion element 70 and the light homogenizing element 50 are housed together in a holding member 55. The swinging device 30 is arranged in contact with the holding member 55, and swings the polarization conversion element 70 and the light homogenizing element 50 together via the holding member 55.

[0111] In the lighting device 2B according to this modification example, by swinging the light homogenizing element 50 using the swinging device 30, it is possible to reduce the uneven illuminance caused by the interference of light. In the case of this modification example, when the light homogenizing element 50 is swung by the swinging device 30, the polarization conversion element 70 swings together with the light homogenizing element 50. Therefore, the positional relationship between each second microlens 54 of the second lens array surface 51b and each incident opening 70K of the polarization conversion element 70 can be made constant.

[0112] Therefore, in the lighting device 2B of this modification example, when the polarization conversion element 70 and the light homogenizing element 50 are swung together by the swinging device 30, by making the polarization direction of the illumination light WL uniform in one direction, it is also possible to efficiently transmit the red illumination light R, green illumination light G, and blue illumination light B separated from the illumination light WL through the polarizing plates arranged on the incident sides of the respective light modulation devices 4R, 4G, 4B. Therefore, the lighting device 2B of this modification example can further improve the light utilization efficiency of the illumination light WL.

[0113] In this modification example, the case where the polarization conversion element 70 swings together with the light homogenizing element 50 is cited as an example, but a structure in which the polarization conversion element does not swing and only the light homogenizing element 50 swings can also be adopted. In the case where only the light homogenizing element 50 swings, as the polarization conversion element, a configuration in which each incident opening corresponds to a plurality of second microlenses 54 in the light homogenizing element 50 is preferably used. If a polarization conversion element having such a configuration is used, even when only the light homogenizing element 50 swings, the light emitted from the second microlenses 54 of the light homogenizing element 50 can be well taken into the polarization conversion element.

[0114] In addition, 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 gist of the present invention.

[0115] 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-described embodiments are not limited to the above-described embodiments, and can be appropriately changed.

[0116] For example, in the lighting devices of the above-described embodiments and modification examples, the case where the light obtained by synthesizing three color lights is emitted as the illumination light is cited as an example, but the present invention can also be applied to a lighting device that emits monochromatic illumination light. In a monochromatic lighting device, by swinging the light homogenizing element into which the light emitted from one light source is incident, it is possible to reduce the uneven illuminance of the illumination light emitted from the light homogenizing element via the overlapping lens. In addition, such a monochromatic lighting device can also be applied to a projector that uses only one light modulation device.

[0117] In addition, in the lighting devices of the above-described embodiments and modifications, the case of using a diffusion plate has been cited as an example. However, a structure in which a light homogenizing element is swung without using a diffusion plate may also be adopted. Considering this structure, since there is no light scattering effect of the diffusion plate, unevenness of illuminance in the illuminated area is likely to become apparent. However, according to the present invention, by swinging the light homogenizing element, unevenness of illuminance can be made less apparent. That is, by omitting the diffusion plate, the effects of the present invention can be made more remarkable.

[0118] In addition, in the above-described embodiments and modifications, an example in which the light source device of the present invention is mounted on a projector using a liquid crystal panel has been shown. However, the present invention is not limited thereto. The light source device of the present invention can also be applied to a projector using a digital micromirror device as a light modulation device.

[0119] In addition, in the above-described embodiment, an example in which the lighting device of the present invention is applied to a projector has been shown. However, the present invention is not limited thereto. The lighting device of the present invention can also be applied to lighting fixtures, headlamps of automobiles, and the like.

[0120] Hereinafter, a summary of the present disclosure is noted.

[0121] Note 1

[0122] A lighting device, characterized in that the lighting device includes: 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 component that combines the first light and the second light and emits combined light; a light homogenizing element that has 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, the first lens array surface and the second lens array surface being integrated; a swinging device that swings the light homogenizing element; and an overlapping lens that overlaps the light emitted from the light homogenizing element.

[0123] In the lighting device having this structure, the first lens array surface and the second lens array surface are integrally swung by the swinging device. As a result, unevenness of illuminance of the illumination light that illuminates the illuminated area is difficult to be visually recognized, in the same way as when the illuminated area of the lighting device is swung in appearance.

[0124] Note 2

[0125] The lighting device according to Note 1, characterized in that the swinging device swings the first lens array surface and the second lens array surface integrally in a direction orthogonal to the optical axis of the light homogenizing element.

[0126] With this structure, the swinging device swings the first lens array surface and the second lens array surface integrally in a direction orthogonal to the optical axis, whereby unevenness of illuminance can be made less apparent.

[0127] Supplementary Note 3

[0128] The lighting device according to Supplementary Note 1 or 2, characterized in that the swinging device swings the first lens array surface and the second lens array surface integrally 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.

[0129] According to this structure, the swinging device swings the first lens array surface and the second lens array surface integrally in two directions, thereby making the illuminance unevenness less obvious.

[0130] Supplementary Note 4

[0131] The lighting device according to any one of Supplementary Notes 1 to 3, characterized in that the first lens array surface and the second lens array surface are an optical component integrally formed, and the swinging device swings the optical component.

[0132] According to this structure, by swinging the light homogenizing element composed of an optical component integrally formed with the first lens array surface and the second lens array surface, the illuminance unevenness of the combined light can be reduced.

[0133] Supplementary Note 5

[0134] The lighting device according to any one of Supplementary Notes 1 to 4, characterized in that it further comprises a holding member that integrally holds a first optical component including the first lens array surface and a second optical component 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, and the swinging device swings the holding member.

[0135] According to this structure, by swinging the light homogenizing element in which the first lens array surface and the second lens array surface are composed of separate optical components, the illuminance unevenness of the combined light can be reduced.

[0136] Supplementary Note 6

[0137] The lighting device according to any one of Supplementary Notes 1 to 5, characterized in that the lighting device further has a polarization conversion element, which is arranged between the light homogenizing element and the overlapping lens, and makes the light emitted from the light homogenizing element coincide with a specified polarization direction.

[0138] According to this structure, the polarization direction of the combined light can be made to coincide with the specified polarization direction.

[0139] Supplementary Note 7

[0140] The lighting device according to Note 6 is characterized in that the swinging device swings the polarization conversion element together with the light homogenizing element.

[0141] According to this structure, since the light homogenizing element and the polarization conversion element swing integrally, the light emitted from the light homogenizing element can be efficiently incident on the polarization conversion element.

[0142] Note 8

[0143] The lighting device according to any one of Notes 1-7 is characterized in that the lighting device further includes: a diffusion plate that diffuses the combined light incident from the light combining component; and a collimating element that collimates the combined light emitted from the diffusion plate.

[0144] According to this structure, by diffusing the combined light, the uniformity of the illuminance distribution can be improved, making the illuminance unevenness less obvious. In addition, by collimating the light diffused by the diffusion plate, the enlargement of the size of the light homogenizing element can be suppressed.

[0145] Note 9

[0146] The lighting device according to any one of Notes 1-8 is characterized in that the frequency of the swing generated by the swinging device is 60 Hz or more and 500 Hz or less.

[0147] According to this structure, the cost of the swinging device can be suppressed and the illuminance unevenness can be efficiently reduced.

[0148] Note 10

[0149] The lighting device according to any one of Notes 1-9 is characterized in that the lighting device further includes a third light source that emits third light in a third band different from the first band and the second band, and the light combining component emits the combined light obtained by combining the third light with the first light and the second light.

[0150] According to this structure, the speckle noise of the combined light including three kinds of colored lights can be reduced.

[0151] Note 11

[0152] The lighting device according to any one of Notes 1-10 is characterized in that the first light source and the second light source are laser light sources.

[0153] According to this structure, by using laser as the illumination light, light interference is likely to occur, so the effect of reducing the illuminance unevenness caused by light interference of the present invention can be obtained more significantly.

[0154] Note 12

[0155] A projector, characterized in that the projector has: a lighting device according to any one of Appendices 1 to 11; a light modulation device that modulates light emitted from the lighting device; and a projection optical device that projects the light modulated by the light modulation device, and the first lens array surface is optically conjugate to an image generation region where an image is generated in the light modulation device.

[0156] In the projector according to this structure, by swinging the first lens array surface conjugate to the projection surface, it is possible to display a high-quality image with suppressed illuminance unevenness and speckle noise without degrading the quality of the projected image.

Claims

1. A lighting device, characterized in that: The lighting device has: a first light source emitting a first light in a first wavelength band; a second light source that emits a second light in a second wavelength band different from the first wavelength band; a light combining member for combining the first light and the second light to emit combined light; a light homogenizing element having a first lens array surface on which the synthesized light is incident and a second lens array surface from which the light passing through the first lens array surface is emitted, wherein the first lens array surface and the second lens array surface are integrated; a swing device for swinging the light uniformizing element; and The overlapping lens overlaps the light emitted from the light uniformizing element.

2. The lighting device according to claim 1, characterized in that: The swing device swings the first lens array surface and the second lens array surface integrally in a direction orthogonal to the optical axis of the light uniformizing element.

3. The lighting device according to claim 1, characterized in that: The swing device swings the first lens array surface and the second lens array surface integrally along a first direction orthogonal to an optical axis of the light uniformizing element and a second direction orthogonal to the optical axis and the first direction.

4. The lighting device according to any one of claims 1 to 3, characterized in that: The first lens array surface and the second lens array surface are an optical component formed integrally. The swing device swings the optical component.

5. The lighting device according to any one of claims 1 to 3, characterized in that: The lighting device further comprises a holding member, which 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 a relative position of the first lens array surface with respect to the second lens array surface. The swing device swings the holding member.

6. The lighting device according to any one of claims 1 to 3, characterized in that: The illumination device further includes a polarization conversion element disposed between the light uniformizing element and the superimposing lens and configured to align the light emitted from the light uniformizing element with a predetermined polarization direction.

7. The lighting device according to claim 6, characterized in that: The swing device swings the polarization conversion element together with the light uniformizing element.

8. The lighting device according to any one of claims 1 to 3, characterized in that: The lighting device further comprises: a diffusion plate that diffuses the synthesized light incident from the light synthesizing member; and A collimating element is provided to collimate the synthesized light emitted from the diffusion plate.

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

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

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

12. A projector, characterized in that: The projector features: The lighting device according to any one of claims 1 to 3; a light modulation device for modulating light emitted from the lighting device; as well as a projection optical device for projecting the light modulated by the light modulation device, The first lens array surface is optically in a conjugate relationship with an image generation region in the light modulator that generates an image.

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