Projector

Abstract

To provide a projector capable of suppressing quality deterioration due to color mixture of a projection image.SOLUTION: A projector according to an aspect of the invention includes a light source section that outputs first light and second light in a time sequential manner, a light scanning section that scans light incident from the light source section, a light modulator that modulates the light incident from the light scanning section in accordance with image information, and a projection optical apparatus that projects the light incident from the light modulator. The light scanning part includes a transmissive optical element including a first incidence surface on which the first light is incident, a first exit surface which is parallel to the first incidence surface and from which the first light is emitted, a second incidence surface on which the second light is incident, and a second exit surface which is parallel to the second incidence surface and from which the second light is emitted, the projector includes a first filter that transmits the first light and blocks the second light and a second filter that is provided on at least one of the second incident surface and the second emission surface and transmits the second light and blocks the first light. The transmissive optical element scans the first light and the second light by rotation.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, there is a projector that illuminates a light modulation device such as a liquid crystal panel by scanning light emitted from a light-emitting element over time on the light modulation device. Patent Document 1 listed below discloses a projector that includes a light source device including a light source lamp, a liquid crystal light valve, a polygon mirror provided between the light source device and the liquid crystal light valve, and a projection lens. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-225956 Summary of the Invention [Problem to be solved by the invention]

[0004] When displaying an image using the sequential method in the projector of Patent Document 1, it is necessary to switch the color of light emitted from the light source device at timing corresponding to the vertices that form the corners of the polygon mirror. However, because it is difficult to switch the light incident from the light source device with high precision, there is a risk that color mixing will occur in the light incident on the liquid crystal light valve, degrading the quality of the projected image. [Means for solving the problem]

[0005] In order to solve the above problems, according to a first aspect of the present invention, there is provided an illumination system including: a light source unit that time-sequentially emits first light and second light of a wavelength band different from that of the first light; a light scanning unit that scans an illuminated area with the first light and the second light that are time-sequentially incident from the light source unit; a light modulation device that is disposed in the illuminated area and modulates the light incident from the light scanning unit in accordance with image information; and a projection optical device that projects the light modulated by the light modulation device, wherein the light scanning unit has a first incident surface on which the first light emitted from the light source unit is incident; a first exit surface that is parallel to the first incident surface and exits the first light that is incident from the first incident surface; a second incident surface on which the second light emitted from the light source unit is incident; Provided is a projector having a transmissive optical element including a second exit surface that is parallel to an incident surface and that exits the second light that is incident from the second incident surface; a first filter that is provided on at least one of the first incident surface and the first exit surface of the transmissive optical element and that transmits the first light and blocks the second light; and a second filter that is provided on at least one of the second incident surface and the second exit surface of the transmissive optical element and that transmits the second light and blocks the first light, wherein the first light and the second light are band-like lights that extend in a first direction, and the transmissive optical element rotates around a rotation axis to scan the first light and the second light in a second direction that intersects with the first direction.

[0006] According to a second aspect of the present invention, there is provided a projection optical system including: a light source unit that emits first light and second light in a time-sequential manner; a light scanning unit that scans an illuminated area with the first light and the second light that are time-sequentially incident from the light source unit; a light modulation device that is disposed in the illuminated area and modulates the light incident from the light scanning unit in accordance with image information; and a projection optical device that projects the light modulated by the light modulation device, wherein the light scanning unit has a transmissive optical element including a first incident surface on which the first light emitted from the light source unit is incident; a second incident surface that intersects with the first incident surface and on which the second light emitted from the light source unit is incident; and a first apex that is located at a boundary between the first incident surface and the second incident surface, and the first light and the second light are strip-shaped light extending in a first direction, A projector is provided in which the transmissive optical element rotates around a rotation axis to scan the first light and the second light in a second direction intersecting the first direction, and the first light and the second light are not incident on the first apex of the transmissive optical element.

[0007] According to a third aspect of the present invention, there is provided a projection optical system including: a light source unit that time-sequentially emits first light and second light having a wavelength band different from that of the first light; a light scanning unit that scans an illuminated area with the first light and the second light that are time-sequentially incident from the light source unit; a light modulation device that is disposed in the illuminated area and modulates the light incident from the light scanning unit in accordance with image information; and a projection optical device that projects the light modulated by the light modulation device, wherein the light scanning unit includes a first incident surface on which the first light emitted from the light source unit is incident; a second incident surface that intersects with the first incident surface and on which the second light emitted from the light source unit is incident; and a first apex that is located at a boundary between the first incident surface and the second incident surface. a transmission optical element including a first light source and a second light source, the first light and the second light being band-shaped light extending in a first direction, the transmission optical element rotating around a rotation axis to scan the first light incident on a first portion of the first incident surface and the second light incident on a second portion of the second incident surface in a second direction intersecting the first direction on a light modulation area of ​​the light modulation device, and to scan the first light incident on a third portion of the first incident surface that is closer to the first apex than the first portion and the first apex, and the second light incident on a fourth portion of the second incident surface that is closer to the first apex than the second portion and the first apex in the second direction outside the light modulation area. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view showing a schematic configuration of a projector according to a first embodiment. [Figure 2A] 10A and 10B are schematic diagrams illustrating the behavior of red light when a transmissive optical element rotates. [Figure 2B] 10A and 10B are schematic diagrams illustrating the behavior of red light when a transmissive optical element rotates. [Figure 2C]10A and 10B are schematic diagrams illustrating the behavior of red light when a transmissive optical element rotates. [Figure 2D] 10A and 10B are schematic diagrams illustrating the behavior of red light when a transmissive optical element rotates. [Figure 2E] 10A and 10B are schematic diagrams illustrating the behavior of red light when a transmissive optical element rotates. [Figure 3] 10A and 10B are diagrams illustrating the behavior of light passing through a transmissive optical element when color light is switched. [Figure 4] 10A and 10B are diagrams illustrating behavior of light when switching color light in a comparative example. [Figure 5] FIG. 10 is a diagram showing a configuration of a main part of a light scanning unit of a first modified example. [Figure 6] 10A and 10B are diagrams illustrating the behavior of light passing through a transmissive optical element of a first modified example. [Figure 7] FIG. 10 is a diagram showing the configuration of a main part of a light scanning unit according to a second modified example. [Figure 8] 10A and 10B are diagrams illustrating behavior of illumination light from a light source device according to a second embodiment. [Figure 9] FIG. 10 is a diagram showing the configuration of a main part of an optical scanning unit according to a third embodiment. [Figure 10A] 13A and 13B are diagrams illustrating behavior of red light by a light scanning unit according to a fourth embodiment. [Figure 10B] 13A and 13B are diagrams illustrating behavior of red light by a light scanning unit according to a fourth embodiment. [Figure 10C] 13A and 13B are diagrams illustrating behavior of red light by a light scanning unit according to a fourth embodiment. [Figure 10D] 13A and 13B are diagrams illustrating behavior of red light by a light scanning unit according to a fourth embodiment. [Figure 10E] 13A and 13B are diagrams illustrating behavior of red light by a light scanning unit according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) A first embodiment of the present invention will be described below with reference to the drawings. The projector of this embodiment is an example of a liquid crystal projector that uses a liquid crystal panel as a light modulation device. In the drawings below, the dimensions of some components may be shown on different scales to make them easier to see.

[0010] FIG. 1 is a plan view showing a schematic configuration of a projector according to this embodiment. 1, a projector 100 of this embodiment includes a light source device 1, a light modulation device 2, an exit-side polarizing plate 3, and a projection optical device 4. The light source device 1 includes a light source section 10 and a light scanning section 12.

[0011] The following description will be given using an XYZ Cartesian coordinate system in the drawings as necessary. The X axis is an axis parallel to the illumination optical axis AX of the light source device 1. The illumination optical axis AX of the light source device 1 is defined as an axis along the chief ray of the illumination light L emitted from the light source unit 10. The Y axis is an axis perpendicular to the X axis and is an axis along the rotation axis O of the transmissive optical element 13 of the optical scanning unit 12. The Z axis is an axis perpendicular to the X axis and Y axis.

[0012] Light source unit 10 is disposed on the -X side of optical scanning unit 12. Light source unit 10 includes red light emitting unit 10R, green light emitting unit 10G, blue light emitting unit 10B, and optical path conversion optical system 11. Light source unit 10 causes red light emitting unit 10R, green light emitting unit 10G, and blue light emitting unit 10B to emit light at different timings.

[0013] The optical axis AX1 of the red light-emitting unit 10R coincides with the illumination optical axis AX of the light source device 1. The red light-emitting unit 10R is disposed so that the optical axis AX1 of the red light-emitting unit 10R is perpendicular to the optical axis AX2 of the green light-emitting unit 10G. The blue light-emitting unit 10B is disposed so that the optical axis AX3 of the blue light-emitting unit 10B is perpendicular to the optical axis AX1 of the red light-emitting unit 10R. The red light-emitting unit 10R emits red light LR toward the +X side. The green light-emitting unit 10G emits green light LG toward the -Z side. The blue light-emitting unit 10B emits blue light LB toward the -Z side.

[0014] The red light-emitting unit 10R is composed of multiple light-emitting elements 10R1, each of which is a laser diode, that emits light in a first wavelength band. Therefore, the light emitted from the red light-emitting unit 10R is linearly polarized light with coherence, a narrow beam width, and high parallelism. The first wavelength band is, for example, a red wavelength band of 650 nm ± 5 nm. That is, the red light-emitting unit 10R emits red light LR. The multiple light-emitting elements 10R1 are arranged in a row along the Y-axis direction at predetermined intervals. The red light-emitting unit 10R of this embodiment emits red light LR that includes light rays from each of the light-emitting elements 10R1 aligned in the Y-axis direction. Therefore, the cross-sectional shape of the red light LR emitted by the red light-emitting unit 10R, taken perpendicular to the principal ray, is a strip shape with a major axis extending along the Y-axis direction.

[0015] The green light-emitting unit 10G is composed of a plurality of light-emitting elements 10G1, each of which is a laser diode, that emits light in a second wavelength band. The second wavelength band is, for example, a green wavelength band of 530 nm±5 nm. That is, the green light-emitting unit 10G emits green light LG. The plurality of light-emitting elements 10G1 are arranged in a row along the Y-axis direction at predetermined intervals. The green light-emitting unit 10G of this embodiment emits green light LG that includes light rays from each of the light-emitting elements 10G1 that are aligned along the Y-axis direction. Therefore, the cross-sectional shape perpendicular to the principal ray of the green light LG emitted by the green light-emitting unit 10G is a strip shape with a major axis extending along the Y-axis direction.

[0016] The blue light-emitting unit 10B is composed of a plurality of light-emitting elements 10B1, each of which is a laser diode, that emits light in a third wavelength band. The third wavelength band is, for example, a blue wavelength band of 450 nm±5 nm. That is, the blue light-emitting unit 10B emits blue light LB. The plurality of light-emitting elements 10B1 are arranged in a row along the Y-axis direction at predetermined intervals. The blue light-emitting unit 10B of this embodiment emits blue light LB that includes light rays from each of the light-emitting elements 10B1 that are aligned along the Y-axis direction. Therefore, the cross-sectional shape perpendicular to the principal ray of the blue light LB emitted by the blue light-emitting unit 10B is a strip shape with a major axis extending along the Y-axis direction.

[0017] In this embodiment, the red light LR corresponds to an example of the "first light" of the present invention, the green light LG corresponds to an example of the "second light of a different wavelength band from the first light" of the present invention, and the blue light LB corresponds to an example of the "third light of a different wavelength band from the first light and the second light" of the present invention.

[0018] The optical path conversion optical system 11 includes a first dichroic mirror 11a and a second dichroic mirror 11b. The first dichroic mirror 11a is provided at a position where the optical axes AX1 and AX2 intersect. The first dichroic mirror 11a transmits the red light LR and reflects the green light LG. The second dichroic mirror 11b is provided at a position where the optical axes AX2 and AX3 intersect. The second dichroic mirror 11b transmits the red light LR and the green light LG and reflects the blue light LB. In this way, the optical path conversion optical system 11 converts the optical paths of the red light LR, the green light LG, and the blue light LB, which are sequentially emitted from the red light emitter 10R, the green light emitter 10G, and the blue light emitter 10B, respectively, in directions along the illumination optical axis AX.

[0019] Based on this configuration, the light source unit 10 of this embodiment is capable of time-sequentially emitting red light LR, green light LG, and blue light LB as illumination light L toward the optical scanning unit 12. The red light LR, green light LG, and blue light LB that are time-sequentially incident on the optical scanning unit 12 all have a strip shape elongated in the Y-axis direction. In this embodiment, the Y-axis direction along the longitudinal direction of the red light LR, green light LG, and blue light LB corresponds to an example of the "first direction" of the present invention.

[0020] The optical scanning unit 12 is provided on the illumination optical axis AX between the light source unit 10 and the optical modulation device 2. The optical scanning unit 12 scans the illuminated area with red light LR, green light LG, and blue light LB that are incident in time sequential order from the light source unit 10. Specifically, the optical scanning unit 12 scans the color lights LR, LG, and LB in the Z-axis direction at the optical modulation device 2 arranged in the illuminated area. In this embodiment, the Z-axis direction along which the red light LR, green light LG, and blue light LB are scanned corresponds to an example of the "second direction" of the present invention.

[0021] The light modulation device 2 is provided on the light emission side of the light source device 1 on the illumination optical axis AX. The light modulation device 2 modulates the color lights LR, LG, and LB emitted from the light source device 1 according to image information to form image light. A transmissive liquid crystal panel is used for the light modulation device 2. The liquid crystal panel may or may not include a color filter. The liquid crystal panel may be driven by any method, including twisted nematic (TN), vertical alignment (VA), or in-plane switching (IPS) methods, without any particular limitation.

[0022] The light modulation device 2 has a light modulation region 2c and a light-shielding region 2d. The light modulation region 2c is a region in which a plurality of pixels are arranged in a matrix, and modulates and outputs the color light beams LR, LG, and LB incident on the light modulation device 2. The light-shielding region 2d is located around the light modulation region 2c and blocks light beams LR, LG, and LB incident on the light modulation device 2 that do not contribute to modulation. The illuminated region Q, where the color light beams LR, LG, and LB emitted from the light scanning unit 12 of the light source device 1 are scanned, corresponds to the light modulation region 2c. The size and aspect ratio of the light modulation region 2c are designed to match parameters such as the size and refractive index of the transmissive optical element 13 of the light scanning unit 12, which will be described later.

[0023] The exit-side polarizing plate 3 is provided on the illumination optical axis AX between the light modulation device 2 and the projection optical device 4. The exit-side polarizing plate 3 transmits linearly polarized light in a specific direction that is emitted from the light modulation device 2 toward the projection optical device 4. In the present embodiment, laser diodes are used for the light-emitting elements 10R1, 10G1, and 10B1 of the light source section 10, and therefore linearly polarized light is emitted from the light source device 1. Therefore, an entrance-side polarizing plate that is provided on the light entrance side of the light modulation device 2 can be omitted.

[0024] The projection optical device 4 is composed of multiple projection lenses. The projection optical device 4 enlarges and projects the image light modulated by the light modulation device 2 onto a projection surface such as a screen, thereby displaying an image on the projection surface.

[0025] The optical scanning unit 12 includes a transmissive optical element 13, a rotary drive device 14, a first filter 5, a second filter 6, and a third filter . The transmitting optical element 13 is composed of a rotatably supported light-transmitting member. The transmitting optical element 13 is rotatable about a rotation axis O extending along the Y-axis direction. The transmitting optical element 13 is connected to a rotation drive device 14 formed of a motor or the like. The transmitting optical element 13 rotates about the rotation axis O by being driven by the rotation drive device 14.

[0026] The transmissive optical element 13 is made of a transmissive material such as optical glass (e.g., BK7), quartz, or resin. The transmissive optical element 13 has a rectangular prism shape extending along the rotation axis O. The transmissive optical element 13 of this embodiment has a first surface 13a and a second surface 13b that intersect with the rotation axis O, and six side surfaces 13c1, 13c2, 13c3, 13c4, 13c5, and 13c6 that are perpendicular to the first surface 13a and the second surface 13b. That is, the shape of the transmissive optical element 13 is a regular hexagonal prism having eight flat surfaces including the first surface 13a, the second surface 13b, and the six side surfaces 13c1, 13c2, 13c3, 13c4, 13c5, and 13c6. The cross-sectional shape of the transmissive optical element 13 taken along a plane perpendicular to the rotation axis O is a regular hexagon. That is, the six side surfaces 13c1, 13c2, 13c3, 13c4, 13c5, and 13c6 have the same area, and two side surfaces facing each other are parallel to each other.

[0027] In this specification, when two surfaces of the transmissive optical element 13 are said to be parallel to each other, the angle between the two surfaces is said to be in the range of 0±5 degrees, taking into consideration the processing accuracy of the glass material that makes up the translucent member, the allowable range of parallelism of light, etc.

[0028] The light source unit 10 emits red light LR at a timing when the side surfaces 13c1 and 13c4 of the six side surfaces 13c1, 13c2, 13c3, 13c4, 13c5, and 13c6 of the transmissive optical element 13 rotating about the rotation axis O overlap with the illumination optical axis AX. Here, in the transmissive optical element 13, a side surface onto which the red light LR emitted from the light source unit 10 is incident is referred to as a first incident surface, and a side surface parallel to the first incident surface and from which the red light LR incident from the first incident surface is emitted is referred to as a first exit surface. In this embodiment, the first incident surface and the first exit surface are any two parallel side surfaces 13c1 and 13c4 among the six side surfaces 13c1, 13c2, 13c3, 13c4, 13c5, and 13c6. More specifically, the first incident surface and the first exit surface alternate between the side surfaces 13c1 and 13c4 every time the transmissive optical element 13 rotates 180 degrees. In this embodiment, the side surfaces 13c1 and 13c4 correspond to an example of the "two first side surfaces parallel to each other" in the present invention.

[0029] The light source unit 10 emits green light LG at a timing when the side surfaces 13c2 and 13c5 of the six side surfaces 13c1, 13c2, 13c3, 13c4, 13c5, and 13c6 of the transmissive optical element 13 rotating about the rotation axis O overlap with the illumination optical axis AX. Here, in the transmissive optical element 13, the side surface onto which the green light LG emitted from the light source unit 10 is incident is referred to as the second incident surface, and the side surface parallel to the second incident surface and from which the green light LG incident from the second incident surface is emitted is referred to as the second exit surface. In this embodiment, the second incident surface and the second exit surface are two parallel side surfaces 13c2 and 13c5 among the six side surfaces 13c1, 13c2, 13c3, 13c4, 13c5, and 13c6. More specifically, the second incident surface and the second exit surface alternate between the side surfaces 13c2 and 13c5 every time the transmissive optical element 13 rotates 180 degrees. In this embodiment, the side surfaces 13c2 and 13c5 correspond to an example of the "two parallel second side surfaces" of the present invention.

[0030] The light source unit 10 emits blue light LB at a timing when the side surfaces 13c3 and 13c6 of the six side surfaces 13c1, 13c2, 13c3, 13c4, 13c5, and 13c6 of the transmissive optical element 13 rotating about the rotation axis O overlap with the illumination optical axis AX. Here, in the transmissive optical element 13, a side surface onto which the blue light LB emitted from the light source unit 10 is incident is referred to as a third entrance surface, and a side surface parallel to the third entrance surface and from which the blue light LB incident from the third entrance surface is emitted is referred to as a third exit surface. In this embodiment, the third entrance surface and the third exit surface are any two parallel side surfaces 13c3 and 13c6 among the six side surfaces 13c1, 13c2, 13c3, 13c4, 13c5, and 13c6. More specifically, the third entrance surface and the third exit surface alternate between the side surfaces 13c3 and 13c6 every time the transmissive optical element 13 rotates 180 degrees.

[0031] In this embodiment, the transmissive optical element 13 has six side surfaces 13c1, 13c2, 13c3, 13c4, 13c5, and 13c6, but the number of side surfaces does not necessarily have to be six and is preferably 2×m (m: a natural number greater than or equal to 2). For example, if the light source unit 10 emits two colors of light in a time-sequential manner, the number of side surfaces is preferably an even number, such as four or eight. Furthermore, if the light source unit 10 emits three colors of light in a time-sequential manner as in this embodiment, the number of side surfaces is preferably an even multiple of the number of colors of light emitted by the light source unit, such as 12 or 18. If the number of side surfaces is even, then the two opposing side surfaces of all the side surfaces are parallel to each other, and no non-parallel side surfaces exist, so that the parallelism of the light transmitted through the transmissive optical element 13 is maintained, reducing the generation of stray light in the transmissive optical element 13 and improving the light utilization efficiency.

[0032] The transmissive optical element 13 may be made of quartz. In the transmissive optical element 13, as the amount of light transmitted through the transmissive member increases, the amount of light absorbed by the transmissive member also increases, which may cause thermal distortion in the transmissive member. In this case, the polarization direction of the illumination light L emitted from the light source unit 10 is disturbed, and linearly polarized light incident on the transmissive member becomes elliptically polarized light and is emitted from the transmissive member. As a result, the effect of obtaining a predetermined contrast without an incident-side polarizing plate by using laser diodes for each light-emitting element of the light source unit 10 in the projector 100 is lost. In other words, even if the light source unit 10 uses laser diodes, an incident-side polarizing plate is required to align the polarization direction. Therefore, to achieve the above effect, it is desirable to use a glass material with a small Young's modulus and thermal expansion coefficient as a glass material with little thermal distortion, and quartz is a desirable example.

[0033] The first filters 5 are provided on two mutually opposing side surfaces of the six side surfaces 13c1, 13c2, 13c3, 13c4, 13c5, and 13c6. In the present embodiment, the first filters 5 are provided on the side surfaces 13c1 and 13c4, which form the first incident surface onto which the red light LR emitted from the light source unit 10 is incident and the first exit surface from which the red light LR exits.

[0034] The first filter 5 transmits red light LR and blocks green light LG and blue light LB. The first filter 5 is formed, for example, of a dichroic film. The first filter 5 reflects the green light LG and blue light LB to prevent them from entering the inside of the transmissive optical element 13 from the side surfaces 13c1 and 13c4. In FIG. 1, for ease of viewing, the first filter 5 is shown spaced apart from the side surfaces of the transmissive optical element 13. The same applies to the second filter 6 and third filter 7 described below.

[0035] The second filters 6 are provided on two of the six side surfaces 13c1, 13c2, 13c3, 13c4, 13c5, and 13c6 that are opposed to each other and that do not have the first filters 5. In the present embodiment, the second filters 6 are provided on the side surfaces 13c2 and 13c5 that form the second incident surface onto which the green light LG emitted from the light source unit 10 is incident and the second exit surface from which the green light LG exits.

[0036] The second filter 6 transmits the green light LG and blocks the red light LR and blue light LB. The second filter 6 is formed, for example, of a dichroic film. The second filter 6 reflects the red light LR and blue light LB, thereby preventing the red light LR and blue light LB from entering the interior of the transmissive optical element 13 through the side surfaces 13c2 and 13c5.

[0037] The third filters 7 are provided on two of the six side surfaces 13c1, 13c2, 13c3, 13c4, 13c5, and 13c6 that are opposed to each other and that do not have the first filters 5 and the second filters 6. In the present embodiment, the third filters 7 are provided on the side surfaces 13c3 and 13c6 that form the third incident surface onto which the blue light LB emitted from the light source unit 10 is incident and the third exit surface from which the blue light LB exits.

[0038] The third filter 7 transmits blue light LB and blocks red light LR and green light LG. The third filter 7 is formed, for example, of a dichroic film. The third filter 7 reflects red light LR and green light LG, thereby preventing the red light LR and green light LG from entering the interior of the transmissive optical element 13 through the side surfaces 13c3 and 13c6.

[0039] Based on this configuration, in the light source device 1 of this embodiment, the side surfaces 13c1 and 13c4 on which the first filter 5 is provided selectively transmit red light LR of the illumination light L incident from the light source unit 10, allowing it to enter the interior of the transmissive optical element 13. Furthermore, the side surfaces 13c2 and 13c5 on which the second filter 6 is provided selectively transmit green light LG of the illumination light L incident from the light source unit 10, allowing it to enter the interior of the transmissive optical element 13. Furthermore, the side surfaces 13c3 and 13c6 on which the third filter 7 is provided selectively transmit blue light LB of the illumination light L incident from the light source unit 10, allowing it to enter the interior of the transmissive optical element 13.

[0040] Furthermore, in the light source device 1 of this embodiment, the filters 5, 6, and 7 block the colored light by reflecting it, so heat generation due to light absorption during light blocking is less likely to occur compared to when the filters block the colored light by absorbing it. Therefore, the light source device 1 of this embodiment can prevent problems such as distortion or deformation of the transmissive optical element 13 due to heat generation by the filters 5, 6, and 7.

[0041] The following describes the behavior of the illumination light L when it passes through the transmissive optical element 13. Since the behavior of each of the color lights LR, LG, and LB is similar, the behavior of the red light LR of the illumination light L will be illustrated and described below.

[0042] 2A to 2E are schematic diagrams for explaining the behavior of the red light LR when the transmissive optical element 13 rotates. In this example, when viewed from the +Y side, the transmissive optical element 13 rotates clockwise around the rotation axis O, and time passes from FIG. 2A to FIG. 2E. The rotary drive device 14 and the filters 5, 6, and 7 are not shown in FIGS. 2A to 2E.

[0043] 2A to 2E, the angle formed by a line M connecting the rotation axis O with the apex 13d, which is the intersection of the side surfaces 13c1 and 13c6, and the illumination optical axis AX is defined as the rotation angle of the transmissive optical element 13. In reality, the red light LR has a predetermined luminous flux width in the Z-axis direction, but here we will focus on the behavior of the chief ray traveling on the illumination optical axis AX. 2A to 2E, the left side shows the displacement d of the chief ray of the red light LR from the illumination optical axis AX, and the right side shows how the red light LR scans the light modulation area 2c, which is the illuminated area Q.

[0044] FIG. 2A shows the initial state of the transmissive optical element 13. That is, in FIG. 2A, the transmissive optical element 13 is not rotated, the line M and the illumination optical axis AX overlap, and the rotation angle θ is 0 degrees. At this time, the red light LR is incident on the end of the side surface 13c1 on the -Z side at an incident angle (30 degrees). The red light LR is refracted in the direction shown in the figure (the -Z side) and travels inside the transmissive optical element 13. Next, the red light LR is incident on the side surface 13c4 at the same incident angle as on the side surface 13c1, so it is refracted at the side surface 13c4 and is emitted from the transmissive optical element 13. At this time, because the side surfaces 13c1 and 13c4 are parallel to each other, the incident angle of the red light LR with respect to the side surface 13c1 is equal to the incident angle of the red light LR with respect to the side surface 13c4. Therefore, the refraction angle of the red light LR incident on the side surface 13c1 and the refraction angle of the red light LR emitted from the side surface 13c4 have opposite signs but equal absolute values. This causes the refraction angle of the red light LR when it enters the side surface 13c1 to cancel out the refraction angle when it exits from the side surface 13c4. As a result, the red light LR travels parallel to the illumination optical axis AX at a position displaced by a displacement amount d from the illumination optical axis AX to the -Z side. As a result, the red light LR emitted from the transmitting optical element 13 is incident on the end 2c1 on the −Z side of the light modulation region 2c of the light modulation device 2, which is the illuminated region Q.

[0045] Next, as shown in Figure 2B, when the rotation angle θ of the transmissive optical element 13 becomes larger than that in Figure 2A, the angle of incidence of the red light LR becomes smaller, and the angle of refraction also becomes smaller. Therefore, the displacement d of the red light LR from the illumination optical axis AX becomes smaller than that in Figure 2A. Furthermore, the state in which the red light LR travels parallel to the illumination optical axis AX is always maintained. When the rotation angle θ is between 0 and 30 degrees, the displacement d decreases monotonically as the rotation angle θ increases. As a result, the red light LR emitted from the transmissive optical element 13 is incident on the +Z side of the light modulation region 2c of the light modulation device 2, compared to the case of FIG. 2A.

[0046] Next, as shown in FIG. 2C, when the rotation angle θ of the transmissive optical element 13 becomes 30 degrees, which is even larger than that in FIG. 2B, the line M and the illumination optical axis AX overlap, and the red light LR is incident perpendicularly on the side surface 13c1. In other words, the incident angle of the red light LR with respect to the side surface 13c1 is 0 degrees. Therefore, the red light LR is incident perpendicularly on the side surface 13c1 and travels along the illumination optical axis AX inside the transmissive optical element 13 without being refracted at the side surface 13c1. Next, the red light LR is also incident perpendicularly on the side surface 13c4, which is parallel to the side surface 13c1. Therefore, the light ray is emitted from the transmissive optical element 13 without being refracted at the side surface 13c4 either, and travels along the illumination optical axis AX. At this time, the red light LR emitted from the transmissive optical element 13 is incident on the center of the light modulation region 2c of the light modulation device 2 in the Z-axis direction.

[0047] Next, as shown in FIG. 2D, when the rotation angle θ of the transmissive optical element 13 exceeds 30 degrees, the incident position of the red light LR shifts from the center of the side surface 13c1 to the side surface 13c2. At this time, the red light LR is refracted at the side surface 13c1, but the refraction direction changes from that in the period up to FIG. 2B, and the red light LR is refracted in the direction shown in the figure (toward the +Z side). The relationship in which the refraction angle of the red light LR when it enters the side surface 13c1 and the refraction angle when it exits the side surface 13c4 cancel each other out remains the same as in the period up to FIG. 2B. As a result, the red light LR travels parallel to the illumination optical axis AX at a position displaced by a displacement amount d toward the +Z side from the illumination optical axis AX. When the rotation angle θ is between 30 degrees and 60 degrees, the displacement amount d increases monotonically as the rotation angle θ increases. As a result, the red light LR emitted from the transmissive optical element 13 is incident on the +Z side of the center of the light modulation region 2c of the light modulation device 2.

[0048] Next, as shown in FIG. 2E, the rotation angle θ of the transmissive optical element 13 reaches a maximum, and the displacement amount d reaches a maximum while maintaining the state in which the red light LR travels parallel to the illumination optical axis AX. As a result, the red light LR emitted from the transmitting optical element 13 is incident on the end 2c2 on the +Z side of the light modulation region 2c of the light modulation device 2, which is the illuminated region Q. In this way, the red light LR incident on the side surface 13c1 of the rotating transmissive optical element 13 can scan the light modulation region 2c of the light modulation device 2 in the Z-axis direction.

[0049] 2E, the apex 13d1 located at the boundary between the side surface 13c1 and the side surface 13c2 of the transmissive optical element 13 overlaps with the illumination optical axis AX. In this embodiment, at the timing shown in FIG. 2E, the light source unit 10 switches the emitted light from red light LR to green light LG.

[0050] FIG. 3 is a diagram showing the behavior of light transmitted through the transmissive optical element 13 when the red light LR is switched to the green light LG. 3, the red light LR has a predetermined luminous flux width in the Z-axis direction and therefore crosses the top 13d1 and is incident on both the side surface 13c1 and the side surface 13c2. The red light LR incident on the side surface 13c1 passes through the first filter 5 provided on the side surface 13c1, enters the inside of the transmissive optical element 13, and then passes through the side surface 13c4 and the first filter 5 provided on the side surface 13c4 to be emitted. On the other hand, the red light LR incident on the side surface 13c2 is reflected by the second filter 6 provided on the side surface 13c2 and does not enter the inside of the transmissive optical element 13.

[0051] 3, at the timing when the red light LR is switched to the green light LG, the green light LG has a predetermined luminous flux width in the Z-axis direction, just like the red light LR, and therefore crosses the top 13d1 and is incident on both the side surface 13c1 and the side surface 13c2. The green light LG that is incident on the side surface 13c1 is reflected by the first filter 5 provided on the side surface 13c1 and does not enter the inside of the transmissive optical element 13. On the other hand, the green light LG that is incident on the side surface 13c2 passes through the second filter 6 provided on the side surface 13c2, enters the inside of the transmissive optical element 13, and then passes through the side surface 13c5 and the second filter 6 provided on the side surface 13c5 before emerging.

[0052] Therefore, when switching from red light LR to green light LG, the red light LR emitted from the transmitting optical element 13 is incident on the +Z side end 2c2 of the optical modulation region 2c of the optical modulation device 2, and the green light LG emitted from the transmitting optical element 13 is incident on the -Z side end 2c1 of the optical modulation region 2c of the optical modulation device 2.

[0053] Here, a comparative example will be described in which a projector using a transmission optical element that does not have the first, second, and third filters on the six side surfaces is used. 4 is a diagram showing the behavior of light passing through the transmissive optical element 130 when switching from red light LR to green light LG in the comparative example projector 1000. In the upper and lower parts of FIG. 4, the diagram on the left shows how the red light LR or green light LG enters the transmissive optical element 130, and the diagram on the right shows how the red light LR or green light LG enters the light modulation region 2c.

[0054] As shown in the upper part of Fig. 4, in the transmissive optical element 130 of the comparative example projector 1000, red light LR incident on the side surface 13c1 and the side surface 13c2 passes through the inside of the transmissive optical element 13 and is emitted from the side surface 13c4 and the side surface 13c5, respectively. Also, as shown in the lower part of Fig. 4, in the transmissive optical element 130 of the comparative example projector 1000, green light LG incident on the side surface 13c1 and the side surface 13c2 passes through the inside of the transmissive optical element 13 and is emitted from the side surface 13c4 and the side surface 13c5, respectively.

[0055] In the comparative example projector 1000, when switching from red light LR to green light LG, the red light LR and green light LG emitted from the transmissive optical element 130 are sequentially incident on both ends of the light modulation area 2c in the Z-axis direction. In other words, when switching colors, different color lights are sequentially incident on the same area (both ends in the Z-axis direction) of the light modulation area 2c over time, which causes a problem of degradation in quality of the projected image due to color mixing.

[0056] In contrast, according to the projector 100 of this embodiment, when switching from red light LR to green light LG, the red light LR and the green light LG are not incident sequentially on the same region of the light modulation region 2c of the light modulation device 2. Therefore, the projector 100 of this embodiment can suppress degradation in the quality of the projected image due to color mixing, as occurs in the transmissive optical element 130 of the comparative example.

[0057] In the projector 100 of this embodiment, the green light LG emitted from the light source unit 10 is incident on the side surface 13c2 of the rotating transmissive optical element 13 and is emitted from the side surface 13c5 along the illumination optical axis AX, thereby scanning the light modulation region 2c of the light modulation device 2 in the Z-axis direction, similar to the red light LR. While the above description has been given of an example in which red light LR is switched to green light LG, the same applies to the case in which green light LG is switched to blue light LB. In other words, according to the projector 100 of this embodiment, even when switching from green light LG to blue light LB, the green light LG and blue light LB are not incident sequentially on the same region of the light modulation region 2c of the light modulation device 2, thereby suppressing degradation in the quality of the projected image due to color mixture.

[0058] Furthermore, in the projector 100 of this embodiment, the blue light LB emitted from the light source unit 10 is incident on the side surface 13c3 of the rotating transmissive optical element 13 and is emitted from the side surface 13c6 along the illumination optical axis AX, thereby scanning the light modulation region 2c of the light modulation device 2 in the Z-axis direction, just like the red light LR and green light LG. The same can be said for switching from blue light LB to red light LR. In other words, according to the projector 100 of this embodiment, even when switching from blue light LB to red light LR, the blue light LB and red light LR are not incident sequentially on the same region of the light modulation region 2c of the light modulation device 2, so that degradation of the quality of the projected image due to color mixture can be suppressed.

[0059] As described above, the projector 100 of this embodiment comprises a light source unit 10 that emits red light LR, green light LG, and blue light LB in a time-sequential manner, an optical scanning unit 12 that scans the red light LR, green light LG, and blue light LB that are incident in a time-sequential manner from the light source unit 10 over an illuminated area Q, an optical modulation device 2 that is arranged in the illuminated area Q and modulates the light incident from the optical scanning unit 12 according to image information, and a projection optical device 4 that projects the light modulated by the optical modulation device 2. The optical scanning unit 12 is a transmissive optical element including a first incident surface into which the red light LR emitted from the light source unit 10 is incident, a first exit surface that is parallel to the first incident surface and from which the red light LR incident from the first incident surface is emitted, a second incident surface into which the green light LG emitted from the light source unit 10 is incident, a second exit surface that is parallel to the second incident surface and from which the green light LG incident from the second incident surface is emitted, a third incident surface into which the blue light LB emitted from the light source unit 10 is incident, and a third exit surface that is parallel to the third incident surface and from which the blue light LB incident from the third incident surface is emitted. The transmitting optical element 13 has a first filter 5 provided on at least one of the first entrance surface and first exit surface of the transmitting optical element 13, which transmits the blue light LB and blocks the green light LG, a second filter 6 provided on at least one of the second entrance surface and second exit surface of the transmitting optical element 13, which transmits the green light LG and blocks the red light LR, and a third filter 7 provided on at least one of the third entrance surface and third exit surface of the transmitting optical element 13, which transmits the blue light LB and blocks the red light LR and green light LG. The transmitting optical element 13 rotates around a rotation axis O to scan the red light LR, green light LG, and blue light LB.

[0060] According to the projector 100 of this embodiment, the first filter 5, the second filter 6, and the third filter 7 are provided, and therefore when the red light LR, the green light LG, and the blue light LB that illuminate the light modulation region 2c of the light modulation device 2 are switched, different color lights are not incident on the same region of the light modulation region 2c of the light modulation device 2. This makes it possible to suppress degradation of the quality of the projected image due to color mixing.

[0061] (First Modification) Next, a first modification of the first embodiment will be described. The projector of this modified example differs from that of the first embodiment in the configuration of the light scanning unit of the light source device, so the same reference numerals are used for the members common to the first embodiment, and detailed descriptions thereof will be omitted.

[0062] FIG. 5 is a diagram showing the configuration of the main part of the optical scanning unit 12A of this modified example. As shown in FIG. 5, the optical scanning unit 12A includes a transmissive optical element 13, a rotary drive device 14, a first filter 5, a second filter 6, and a third filter 7. In the optical scanning unit 12A of this modified example, the first filter 5 is provided on a side surface 13c1, which is one of the side surfaces 13c1 and 13c4, and which forms a first incident surface onto which the red light LR emitted from the light source unit 10 is incident and a first exit surface from which the red light LR is exited. The second filter 6 is provided on a side surface 13c5, which is one of the side surfaces 13c2 and 13c5, and which forms a second incident surface onto which the green light LG emitted from the light source unit 10 is incident and a second exit surface from which the green light LG is exited. The third filter 7 is provided on a side surface 13c6, which is one of the side surfaces 13c3 and 13c6, and which forms a third incident surface onto which the blue light LB emitted from the light source unit 10 is incident and a third exit surface from which the blue light LB is exited.

[0063] The behavior of the illumination light L emitted by the optical scanning unit 12A of this modified example will be described below. In the optical scanning unit 12A of this modified example, red light LR incident on one of the side surfaces 13c1 and 13c4 passes through the transmissive optical element 13 and exits from the other of the side surfaces 13c1 and 13c4, regardless of the presence or absence of the first filter 5. The same can be said about the behavior of green light LG and blue light LB.

[0064] Here, an example will be described in which the light emitted by the light source unit 10 is switched from red light LR to green light LG. Fig. 6 is a diagram showing, from top to bottom, the behavior of light transmitted through the transmissive optical element 13 when switching from red light LR to green light LG in the optical scanning unit 12A of this modified example. In each diagram in Fig. 6, the left side shows how the red light LR or green light LG is displaced from the illumination optical axis AX, and the right side shows how the red light LR or green light LG scans the light modulation area 2c, which is the illuminated area Q. The rotary drive device 14 is not shown in Fig. 6.

[0065] As shown in the top row of Figure 6, the red light LR has a predetermined luminous flux width in the Z-axis direction and therefore straddles the first top portion 13d1 and is incident on both the side surface 13c1 and the side surface 13c2. The red light LR that is incident on the side surface 13c1 passes through the first filter 5 provided on the side surface 13c1, enters the inside of the transmissive optical element 13, and is emitted from the side surface 13c4. On the other hand, the red light LR that is incident on the side surface 13c2 enters the inside of the transmissive optical element 13 and is incident on the side surface 13c5 that is parallel to the side surface 13c2. Then, the red light LR is reflected by the second filter 6 at the side surface 13c5, and is not transmitted through the transmissive optical element 13 and emitted to the outside from the side surface 13c5. In this way, the red light LR emitted from the transmitting optical element 13 is incident on the end 2c2 on the +Z side of the light modulation region 2c of the light modulation device 2.

[0066] As shown in the second row from the top of FIG. 6, when the light source switches from red light LR to green light LG, the green light LG crosses the first top portion 13d1 and enters both the side surface 13c1 and the side surface 13c2. The green light LG that entered the side surface 13c1 is reflected by the first filter 5 provided on the side surface 13c1 and does not enter the interior of the transmissive optical element 13. On the other hand, the green light LG that entered the side surface 13c2 enters from the side surface 13c2, passes through the second filter 6 provided on the side surface 13c5 parallel to the side surface 13c2, and is emitted to the outside of the transmissive optical element 13. In this way, the green light LG that has exited the transmissive optical element 13 enters the end 2c1 on the -Z side of the light modulation region 2c of the light modulation device 2.

[0067] The third row from the top in FIG. 6 shows a state in which the transmissive optical element 13 has been rotated 180 degrees from the state in the top row in FIG. As shown in the third row from the top of Figure 6, the red light LR crosses the top 13d4 and is incident on both the side surface 13c4 and the side surface 13c5. The red light LR that is incident on the side surface 13c4 enters the inside of the transmissive optical element 13, passes through the first filter 5 provided on the side surface 13c1, and is emitted to the outside of the transmissive optical element 13. On the other hand, the red light LR that is incident on the side surface 13c5 is reflected by the second filter 6 provided on the side surface 13c5, and therefore does not enter the inside of the transmissive optical element 13. In this way, the red light LR that is emitted from the transmissive optical element 13 is incident on the end 2c2 on the +Z side of the light modulation region 2c of the light modulation device 2.

[0068] The fourth row from the top of FIG. 6 shows a state in which the transmissive optical element 13 has been rotated 180 degrees from the state in the second row from the top of FIG. As shown in the fourth row from the top of FIG. 6 , when the light source switches from red light LR to green light LG, the green light LG crosses the top 13d4 and enters both the side surface 13c4 and the side surface 13c5. The green light LG that entered the side surface 13c4 enters the interior of the transmissive optical element 13 and is reflected by the first filter 5 provided on the side surface 13c1, and therefore does not pass through the transmissive optical element 13. On the other hand, the green light LG that entered the side surface 13c5 passes through the second filter 6 provided on the side surface 13c5, enters the interior of the transmissive optical element 13, and is emitted to the outside from the side surface 13c2. In this way, the green light LG that has exited from the transmissive optical element 13 enters the end 2c1 on the -Z side of the light modulation region 2c of the light modulation device 2.

[0069] In the above explanation, the case of switching from red light LR to green light LG has been taken as an example, but the same can be said for the case of switching from green light LG to blue light LB.

[0070] Thus, according to the optical scanning unit 12A of this modified example, even if each filter 5, 6, 7 is provided on each side surface of the optical scanning unit 12 of the first embodiment, when switching between red light LR, green light LG, and blue light LB that illuminate the optical modulation region 2c of the optical modulation device 2, different colored lights are not incident on the same region of the optical modulation region 2c of the optical modulation device 2, thereby suppressing degradation in the quality of the projected image due to color mixing.

[0071] (Second Modification) Next, another modification of the first embodiment will be described as a second modification. The projector of this modified example differs from that of the first embodiment in the configuration of the light scanning unit of the light source device, so the same reference numerals are used for the members common to the first embodiment, and detailed descriptions thereof will be omitted.

[0072] In the first modified example, the filters 5, 6, and 7 are provided on three mutually adjacent side surfaces 13c1, 13c6, and 13c5 out of the six side surfaces, but the arrangement of the filters 5, 6, and 7 is not limited to this.

[0073] FIG. 7 is a diagram showing the configuration of the main part of the optical scanning unit 12B of this modified example. As shown in FIG. 7, in the optical scanning unit 12B, the filters 5, 6, and 7 are provided on three side surfaces 13c1, 13c5, and 13c3 that are not adjacent to each other and are arranged alternately among the six side surfaces.

[0074] According to the optical scanning unit 12B of this modified example, different color lights are not sequentially incident on the same region of the optical modulation region 2c of the optical modulation device 2 at the timing of switching between the red light LR, green light LG, and blue light LB that scan the optical modulation region 2c of the optical modulation device 2. This makes it possible to suppress degradation of the quality of the projected image due to color mixing.

[0075] (Second embodiment) A second embodiment of the projector of the invention will be described below. The projector of this embodiment differs from the projector of the first embodiment in that the light source unit of the light source device periodically switches between an on state and an off state, and does not have the first filter, the second filter, and the third filter. Note that the same reference numerals are used for the members common to the first embodiment, and detailed descriptions thereof will be omitted.

[0076] Fig. 8 is a diagram showing the behavior of illumination light L from the light source device of this embodiment. In Fig. 8, the horizontal axis represents time t, and the vertical axis represents the displacement d of illumination light L from the illumination optical axis AX. Fig. 8 shows the period T during which the transmissive optical element 13 makes one rotation, and the timing at which red light LR is perpendicularly incident on side surface 13c1 and emitted from side surface 13c4 is set as the initial state (time t=0).

[0077] In Figure 8, illumination light L with a displacement amount d of 0 is located at the center of the Z-axis direction of the light modulation area 2c of the light modulation device 2, illumination light L with a displacement amount d of + (plus) scans on the -Z side of the center of the light modulation area 2c of the light modulation device 2, and illumination light L with a displacement amount d of - (minus) scans on the +Z side of the center of the light modulation area 2c of the light modulation device 2.

[0078] When the transmissive optical element 13 in the light scanning unit 12 of the light source device of this embodiment makes one rotation, the red light LR, green light LG, and blue light LB emitted from the light source unit 10 are each incident on the side surfaces of the transmissive optical element 13 twice.

[0079] As shown in FIG. 8, the period T during which the transmissive optical element 13 makes one rotation includes two periods each from the first period T1 to the sixth period T6. The first period T1 is a period during which the red light LR is incident on one of the side surfaces 13c1 and 13c4 of the transmissive optical element 13. The second period T2 is a period during which the green light LG is incident on one of the side surfaces 13c2 and 13c5 of the transmissive optical element 13. The third period T3 is a period between the first period T1 and the second period T2, during which the light source unit 10 is in an extinguished state. The third period T3 is defined, for example, as the time from when a portion of the red light LR overlaps with the first apex 13d1 located at the boundary between the side surfaces 13c1 and 13c2 to when the green light LG no longer overlaps with the first apex 13d1 when the green light LG is emitted.

[0080] According to this configuration, the light source unit 10 is turned off at the timing of switching the color light incident on the optical scanning unit 12, so that the red light LR and the green light LG can be prevented from being incident on the first vertex 13d1 of the transmissive optical element 13. Therefore, when switching from the red light LR to the green light LG, the red light LR and the green light LG do not enter across the first vertex 13d1.

[0081] The fourth period T4 is a period during which the blue light LB is incident on one of the side surfaces 13c3 and 13c6 of the transmissive optical element 13. The fifth period T5 is a period between the second period T2 and the fourth period T4, during which the light source unit 10 is turned off. The sixth period T6 is a period between the fourth period T4 and the first period T1, during which the light source unit 10 is turned off. The fifth period T5 is defined, for example, as the time from when a portion of the green light LG overlaps with a second apex located at the boundary between the side surfaces 13c2 and 13c3 to when the blue light LB no longer overlaps with the second apex when the blue light LB is emitted. The sixth period T6 is defined, for example, as the time from when a portion of the blue light LB overlaps with a third apex located at the boundary between the side surfaces 13c3 and 13c4 to when the red light LR no longer overlaps with the third apex when the red light LR is emitted.

[0082] According to this configuration, the light source unit 10 is turned off at the timing of switching the color light incident on the optical scanning unit 12, so that the green light LG and the blue light LB can be prevented from being incident on the second vertex of the transmissive optical element 13. In addition, the blue light LB and the red light LR can be prevented from being incident on the third vertex of the transmissive optical element 13.

[0083] In the second first period T1, the red light LR is incident on the other of the side surfaces 13c1 and 13c4 of the transmissive optical element 13, in the second second period T2, the green light LG is incident on the other of the side surfaces 13c2 and 13c5 of the transmissive optical element 13, and in the second fourth period T4, the blue light LB is incident on the other of the side surfaces 13c3 and 13c6 of the transmissive optical element 13. In the second third period T3, fifth period T5, and sixth period T6, the light source unit 10 is turned off.

[0084] According to the projector of this embodiment, the light source device turns off the light source unit 10 at the timing when it switches the color light to be incident on the optical scanning unit 12, so that when the red light LR, green light LG, and blue light LB that illuminate the light modulation region 2c of the light modulation device 2 are switched, different color lights are not incident on the same region of the light modulation region 2c of the light modulation device 2. This makes it possible to suppress degradation of the quality of the projected image due to color mixing.

[0085] (Third embodiment) A third embodiment of the present invention will now be described. In this embodiment, the configuration of the light scanning unit of the light source device is different from that of the projector of Embodiment 1. Note that the same reference numerals are used for members that are common to the first embodiment, and detailed descriptions thereof will be omitted.

[0086] FIG. 9 is a diagram showing the configuration of the main part of the optical scanning unit 212 of this embodiment. As shown in FIG. 9, the optical scanning unit 212 includes a transmissive optical element 13, a rotary drive device 14, a first light-shielding unit 115, a second light-shielding unit 116, and a third light-shielding unit 117.

[0087] The first light-shielding portion 115 is provided to cover two corners including the apex 13d1 and the apex 13d4 of the transmissive optical element 13, and blocks light incident from the light source portion 10. In this embodiment, the apex 13d1 and the apex 13d4 correspond to an example of the "first apex" of the present invention. Specifically, one first light-shielding portion 115 is provided on the end of side surface 13c1 on the apex 13d1 side, the end of side surface 13c2 on the apex 13d1 side, and the apex 13d1, while the other first light-shielding portion 115 is provided on the end of side surface 13c4 on the apex 13d4 side, the end of side surface 13c5 on the apex 13d4 side, and the apex 13d4.

[0088] The second light-shielding portion 116 is provided to cover two corners including the apex 13d2 and the apex 13d5 of the transmissive optical element 13, and blocks light incident from the light source portion 10. In this embodiment, the apex 13d2 and the apex 13d5 correspond to an example of the "second apex" of the present invention. Specifically, one second light-shielding portion 116 is provided on the end of side surface 13c2 on the apex 13d2 side, the end of side surface 13c3 on the apex 13d1 side, and the apex 13d2, while the other second light-shielding portion 116 is provided on the end of side surface 13c5 on the apex 13d5 side, the end of side surface 13c6 on the apex 13d5 side, and the apex 13d5.

[0089] The third light-shielding portion 117 is provided so as to cover two corners of the transmissive optical element 13, including the apex 13d3 and the apex 13d6, and blocks light incident from the light source portion . Specifically, one third light-shielding portion 117 is provided on the end of side surface 13c3 on the apex 13d3 side, the end of side surface 13c4 on the apex 13d3 side, and the apex 13d3, while the other third light-shielding portion 117 is provided on the end of side surface 13c6 on the apex 13d6 side, the end of side surface 13c1 on the apex 13d6 side, and the apex 13d6.

[0090] Here, in this specification, the width of the light-shielding portion is defined as the length of each of the first light-shielding portion 115, the second light-shielding portion 116, and the third light-shielding portion 117, which are arranged in a bent state relative to the transmissive optical element 13, when extended in a straight line.

[0091] In this embodiment, the width of the first light-shielding portion 115 is equal to or greater than the width of the red light LR and green light LG emitted from the light source unit 10 and incident on the transmissive optical element 13. The width of the second light-shielding portion 116 is equal to or greater than the width of the green light LG and blue light LB emitted from the light source unit 10 and incident on the transmissive optical element 13. The width of the third light-shielding portion 117 is equal to or greater than the width of the red light LR and blue light LB emitted from the light source unit 10 and incident on the transmissive optical element 13. According to this configuration, the light shielding portions 115, 116, and 117 can effectively shield the colored light incident on the top portions of the transmissive optical element 13.

[0092] According to the optical scanning unit 212 of this embodiment, since it includes the first light-shielding unit 115, the second light-shielding unit 116, and the third light-shielding unit 117, when the red light LR, the green light LG, and the blue light LB that illuminate the light modulation region 2c of the light modulation device 2 are switched, different color lights are not incident on the same region of the light modulation region 2c of the light modulation device 2. Therefore, it is possible to suppress degradation of the quality of the projected image due to color mixing.

[0093] In this embodiment, the width of the second light-shielding portion 116 may be different from the width of the first light-shielding portion 115. In other words, the widths of the light-shielding portions 115, 116, and 117 may be different from each other. According to this configuration, even if the luminous flux widths of the red light LR, green light LG, and blue light LB are different from one another, it is possible to provide light-shielding portions 115, 116, and 117 with appropriate widths corresponding to the luminous flux widths of the respective color lights. This makes it possible to effectively block the red light LR, green light LG, and blue light LB, which have different luminous flux widths, and prevent them from entering the apexes of the transmitting optical element 13.

[0094] (Fourth embodiment) A fourth embodiment of the projector of the invention will be described below. The projector of this embodiment differs from the projector of the first embodiment in that part of the light emitted from the light scanning unit scans outside the light modulation area of ​​the light modulation device. Note that the same reference numerals are used for components that are common to the first embodiment, and detailed descriptions thereof will be omitted.

[0095] 10A to 10E are diagrams sequentially showing how the red light LR is scanned over the optical modulation device 2 by the optical scanning unit 312 of this embodiment. For simplicity of explanation, in Figs. 10A to 10E, only the chief ray of the red light LR is shown as a single light ray.

[0096] 10A, the optical scanning unit 312 causes the red light LR incident on the first portion 15a of the side surface 13c1 forming the first incident surface to be incident on the +Z side end of the light modulation region 2c of the light modulation device 2. Here, the first portion 15a of the side surface 13c1 corresponds to a region that allows the red light LR incident on the side surface 13c1 to be scanned on the light modulation region 2c.

[0097] 10B, the optical scanning unit 312 causes the red light LR that has entered the third portion 15c that is closer to the apex 13d1 than the first portion 15a of the side surface 13c1 to enter the light-shielding region 2d that is outside the +Z side of the light modulation region 2c of the light modulation device 2. In this embodiment, the apex 13d1 corresponds to an example of the "first apex" of the present invention.

[0098] 10C, the optical scanning unit 312 causes the red light LR incident on the apex 13d1 of the side surface 13c1 to enter the light-shielding region 2d, which is outside the light-modulation region 2c of the light modulation device 2. Specifically, the red light LR enters the +Z side and the −Z side of the light-shielding region 2d so as to sandwich the light-modulation region 2c in the Z-axis direction. The light emitted from the light source unit 10 is switched to green light LG at the same time as the red light LR is incident on the top portion 13d1. At this time, the green light LG is incident on the +Z side and the -Z side of the light-shielding region 2d, similar to the red light LR, so as to sandwich the light modulation region 2c in the Z-axis direction.

[0099] 10D, the optical scanning unit 312 causes the green light LG that has entered the fourth portion 15d that is closer to the apex 13d1 than the second portion 15b of the side surface 13c2 that forms the second incident surface to be incident on the light-shielding region 2d that is outside the -Z side of the light modulation region 2c of the light modulation device 2. Here, the second portion 15b of the side surface 13c2 corresponds to a region that allows the green light LG that has entered the side surface 13c2 to be scanned over the light modulation region 2c.

[0100] 10E, the optical scanning unit 312 causes the green light LG incident on the second portion 15b of the side surface 13c2 to be incident on the -Z side end of the light modulation region 2c of the light modulation device 2. Thereafter, the optical scanning unit 312 scans the green light LG from the -Z side to the +Z side on the light modulation region 2c of the light modulation device 2 in accordance with the rotation angle of the transmissive optical element 13.

[0101] In the explanation of this embodiment, the behavior of light before and after the light emitted from the light source unit 10 is switched from red light LR to green light LG at the top 13d1 of the transmitting optical element 13 is used as an example, but the same can be said for the behavior of other colored light incident on the transmitting optical element 13.

[0102] As described above, according to the light scanning unit 312 of this embodiment, when switching between the red light LR, green light LG, and blue light LB that scan the light modulation region 2c of the light modulation device 2, the different color lights before and after the switching can be made to enter the light-shielding region 2d that is outside the light modulation region 2c. Therefore, the different color lights before and after the switching are not made to enter the same region of the light modulation region 2c of the light modulation device 2, and therefore degradation of the quality of the projected image due to color mixing can be suppressed.

[0103] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. In addition, the specific description of the shape, number, arrangement, material, etc. of each component of the projector is not limited to the above embodiment and can be changed as appropriate.

[0104] A summary of this disclosure is provided below. (Appendix 1) a light source unit that time-sequentially emits a first light and a second light having a wavelength band different from that of the first light; a light scanning unit that scans an illuminated area with the first light and the second light that are incident from the light source unit in a time-sequential manner; a light modulation device disposed in the illumination area and modulating the light incident from the light scanning unit in accordance with image information; a projection optical device that projects the light modulated by the light modulation device; Equipped with The optical scanning unit a transmissive optical element including: a first incident surface on which the first light emitted from the light source unit is incident; a first exit surface that is parallel to the first incident surface and from which the first light incident from the first incident surface exits; a second incident surface on which the second light emitted from the light source unit is incident; and a second exit surface that is parallel to the second incident surface and from which the second light incident from the second incident surface exits; a first filter provided on at least one of the first entrance surface and the first exit surface of the transmissive optical element, the first filter transmitting the first light and blocking the second light; a second filter provided on at least one of the second entrance surface and the second exit surface of the transmissive optical element, the second filter transmitting the second light and blocking the first light, the first light and the second light are strip-shaped lights extending in a first direction, the transmitting optical element rotates around a rotation axis to scan the first light and the second light in a second direction intersecting the first direction; projector.

[0105] With this configuration of projector, because it is equipped with the first filter and the second filter, when the first light and the second light illuminating the light modulation device are switched at the boundary between the first and second incident surfaces, different color lights before and after the switching are not incident on the same area of ​​the light modulation device, which makes it possible to suppress degradation of the quality of the projected image due to color mixing.

[0106] (Appendix 2) the first filters are provided on the first entrance surface and the first exit surface of the transmissive optical element, the second filters are provided on the second entrance surface and the second exit surface of the transmissive optical element, respectively; 1. The projector according to claim 1.

[0107] According to this configuration, since filters are provided on both the entrance surface and the exit surface of the transmissive optical element, light of a desired color can be extracted from the exit surface, thereby more reliably preventing color mixing.

[0108] (Appendix 3) the light source unit time-sequentially emits, in addition to the first light and the second light, a third light having a wavelength band different from that of the first light and the second light; the transmissive optical element further includes a third incident surface into which the third light emitted from the light source unit is incident, and a third exit surface that is parallel to the third incident surface and through which the third light incident from the third incident surface exits, the optical scanning unit further includes a third filter provided on at least one of the third entrance surface and the third exit surface of the transmissive optical element, the third filter transmitting the third light and blocking the first light and the second light. 1. The projector according to claim 1.

[0109] According to this configuration, even when a light source unit that emits the first light, the second light, and the third light in time sequence is used, it is possible to suppress degradation of the quality of the projected image due to color mixture.

[0110] (Appendix 4) At least one of the first filter, the second filter, and the third filter blocks light by reflection. 2. The projector according to claim 1, wherein the projector is a

[0111] With this configuration, one of the filters blocks light by reflecting it, so heat generation due to light absorption during light blocking is less likely to occur compared to when light is blocked by absorbing it, thereby preventing problems such as distortion or deformation of the transmissive optical element due to heat generated by the filter.

[0112] (Appendix 5) a light source unit that time-sequentially emits a first light and a second light having a wavelength band different from that of the first light; a light scanning unit that scans an illuminated area with the first light and the second light that are incident from the light source unit in a time-sequential manner; a light modulation device disposed in the illumination area and modulating the light incident from the light scanning unit in accordance with image information; a projection optical device that projects the light modulated by the light modulation device; Equipped with The optical scanning unit a transmissive optical element including a first incident surface onto which the first light emitted from the light source unit is incident, a second incident surface that intersects with the first incident surface and onto which the second light emitted from the light source unit is incident, and a first apex portion located at the boundary between the first incident surface and the second incident surface, the first light and the second light are strip-shaped lights extending in a first direction, the transmitting optical element rotates around a rotation axis to scan the first light and the second light in a second direction intersecting the first direction; the first light and the second light are not incident on the first apex of the transmissive optical element; projector.

[0113] According to this configuration, when the light incident on the optical scanning unit is switched from the first light to the second light, the first light and the second light can be prevented from entering the first apex of the transmissive optical element. As a result, when the light illuminating the light modulation device is switched, the first light and the second light of different colors are not incident on the same region of the light modulation device, and therefore degradation of the quality of the projected image due to color mixing can be suppressed.

[0114] (Appendix 6) the transmissive optical element further includes a first exit surface that is parallel to the first incident surface and that emits the first light that has entered through the first incident surface, and a second exit surface that is parallel to the second incident surface and that emits the second light that has entered through the second incident surface. 10. The projector according to claim 5.

[0115] According to this configuration, the first light incident from the first entrance surface can be emitted from the first exit surface, and the second light incident from the second entrance surface can be emitted from the second exit surface.

[0116] (Appendix 7) the transmissive optical element has a front surface and a back surface that intersect with the rotation axis, and 2×m (m: a natural number equal to or greater than 2) side surfaces that are in contact with the front surface and the back surface, the first entrance surface and the first exit surface are two first side surfaces that are parallel to each other among the 2×m side surfaces, The second entrance surface and the second exit surface are two second side surfaces that are different from the first side surfaces among the 2×m side surfaces and are parallel to each other. 7. The projector according to claim 1.

[0117] According to this configuration, since no light is incident on side surfaces that are not parallel to each other, the generation of stray light in the transmissive optical element is reduced, and the light utilization efficiency can be improved.

[0118] (Appendix 8) the optical scanning unit further includes a first light-shielding unit that is provided at an end of the first incident surface on the first apex side, an end of the second incident surface on the first apex side, and the first apex, and that blocks light incident from the light source unit. 10. The projector according to claim 5.

[0119] According to this configuration, the first light-shielding portion can effectively block light incident on the first apex of the transmissive optical element.

[0120] (Appendix 9) a width of the first light-shielding portion is equal to or greater than a width of the first light and the second light when emitted from the light source portion and incident on the transmissive optical element; 10. The projector according to claim 8.

[0121] According to this configuration, the first apex of the transmissive optical element can be reliably covered by the first light-shielding portion, so that light incident on the first apex can be more reliably blocked.

[0122] (Appendix 10) the light source unit time-sequentially emits, in addition to the first light and the second light, a third light having a wavelength band different from that of the first light and the second light; the transmissive optical element further includes a third incident surface onto which the third light emitted from the light source unit is incident, and a second apex portion located at a boundary between the second incident surface and the third incident surface, the optical scanning unit further includes a second light-shielding unit that is provided at an end of the second incident surface on the second apex side, an end of the third incident surface on the second apex side, and the second apex, and that shields light incident from the light source unit; The width of the second light-shielding portion and the width of the first light-shielding portion are different from each other. 10. The projector of claim 8 or 9.

[0123] According to this configuration, even if the first, second, and third lights have different beam widths, it is possible to provide a light-shielding portion with an appropriate width corresponding to the beam width of each light, thereby effectively blocking the lights with different beam widths and preventing them from entering the first or second vertex of the transmissive optical element.

[0124] (Appendix 11) the light source unit periodically repeats an on state and an off state, a period during which the transmissive optical element makes one rotation includes a first period during which the first light emitted from the light source unit is incident on the first incident surface, a second period during which the second light emitted from the light source unit is incident on the second incident surface, and a third period between the first period and the second period, During the third period, the light source unit is turned off. 10. The projector according to claim 5.

[0125] According to this configuration, the light source unit is turned off when the light incident on the optical scanning unit is switched from the first light to the second light, so the first light and the second light can be prevented from entering the boundary between the first and second incident surfaces of the transmissive optical element. Therefore, the first light and the second light do not enter the transmissive optical element so as to straddle the boundary. Therefore, when switching the color light illuminating the light modulation device, different color lights are not incident on the same region of the light modulation device, so degradation of the quality of the projected image due to color mixing can be suppressed.

[0126] (Appendix 12) a light source unit that time-sequentially emits a first light and a second light having a wavelength band different from that of the first light; a light scanning unit that scans an illuminated area with the first light and the second light that are incident from the light source unit in a time-sequential manner; a light modulation device disposed in the illumination area and modulating the light incident from the light scanning unit in accordance with image information; a projection optical device that projects the light modulated by the light modulation device; Equipped with The optical scanning unit a transmissive optical element including a first incident surface onto which the first light emitted from the light source unit is incident, a second incident surface that intersects with the first incident surface and onto which the second light emitted from the light source unit is incident, and a first apex portion located at the boundary between the first incident surface and the second incident surface, the first light and the second light are strip-shaped lights extending in a first direction, The transmitting optical element rotates around a rotation axis, scanning the first light incident on a first portion of the first incident surface and the second light incident on a second portion of the second incident surface in a second direction intersecting the first direction on a light modulation region of the light modulation device; the first light incident on a third portion of the first incident surface closer to the first apex than the first portion and the first apex, and the second light incident on a fourth portion of the second incident surface closer to the first apex than the second portion and the first apex are scanned in the second direction outside the light modulation area. projector.

[0127] With this configuration of the projector, when the first light and the second light scanning the light modulation region of the light modulation device are switched at the first apex located at the boundary between the first entrance surface and the second entrance surface, the different color lights before and after the switching can be made to enter outside the light modulation region. As a result, the different color lights before and after the switching are not incident on the same region of the light modulation device, and degradation of the quality of the projected image due to color mixing can be suppressed. [Explanation of symbols]

[0128] 2...light modulation device, 2c...light modulation region, 4...projection optical device, 5...first filter, 6...second filter, 7...third filter, 10...light source unit, 12, 12A, 12B, 112, 212, 312...light scanning unit, 13...transmission optical element, 13a...first surface, 13b...second surface, 13d1, 13d4...top portion (first top portion), 13d2, 13d5...top portion (second top portion) part), 15a...first part, 15b...second part, 15c...third part, 15d...fourth part, 100...projector, 115...first light shielding part, 116...second light shielding part, 13c1, 13c4...side surface (first side surface), 13c2,13c5...side surface (second side surface), L...illumination light, O...rotation axis, Q...illuminated area, T1...first period, T2...second period, T3...third period.

Claims

1. a light source unit that time-sequentially emits a first light and a second light having a wavelength band different from that of the first light; a light scanning unit that scans an illuminated area with the first light and the second light that are incident from the light source unit in a time-sequential manner; a light modulation device disposed in the illumination area and modulating the light incident from the light scanning unit in accordance with image information; a projection optical device that projects the light modulated by the light modulation device; Equipped with The optical scanning unit a transmissive optical element including: a first incident surface on which the first light emitted from the light source unit is incident; a first exit surface that is parallel to the first incident surface and through which the first light incident from the first incident surface exits; a second incident surface on which the second light emitted from the light source unit is incident; and a second exit surface that is parallel to the second incident surface and through which the second light incident from the second incident surface exits; a first filter provided on at least one of the first entrance surface and the first exit surface of the transmissive optical element, the first filter transmitting the first light and blocking the second light; a second filter provided on at least one of the second entrance surface and the second exit surface of the transmissive optical element, the second filter transmitting the second light and blocking the first light, the first light and the second light are strip-shaped lights extending in a first direction, the transmitting optical element rotates around a rotation axis to scan the first light and the second light in a second direction intersecting the first direction; projector.

2. the first filters are provided on the first entrance surface and the first exit surface of the transmissive optical element, the second filters are provided on the second entrance surface and the second exit surface of the transmissive optical element, respectively; The projector according to claim 1 .

3. the light source unit time-sequentially emits, in addition to the first light and the second light, a third light having a wavelength band different from that of the first light and the second light; the transmissive optical element further includes a third incident surface onto which the third light emitted from the light source unit is incident, and a third exit surface that is parallel to the third incident surface and through which the third light incident from the third incident surface exits, the optical scanning unit further includes a third filter provided on at least one of the third entrance surface and the third exit surface of the transmissive optical element, the third filter transmitting the third light and blocking the first light and the second light. The projector according to claim 1 .

4. At least one of the first filter, the second filter, and the third filter blocks light by reflection. The projector according to claim 3 .

5. a light source unit that time-sequentially emits a first light and a second light having a wavelength band different from that of the first light; a light scanning unit that scans an illuminated area with the first light and the second light that are incident from the light source unit in a time-sequential manner; a light modulation device disposed in the illumination area and modulating the light incident from the light scanning unit in accordance with image information; a projection optical device that projects the light modulated by the light modulation device; Equipped with The optical scanning unit a transmissive optical element including a first incident surface onto which the first light emitted from the light source unit is incident, a second incident surface that intersects with the first incident surface and onto which the second light emitted from the light source unit is incident, and a first apex portion located at a boundary between the first incident surface and the second incident surface, the first light and the second light are strip-shaped lights extending in a first direction, the transmission optical element rotates around a rotation axis to scan the first light and the second light in a second direction intersecting the first direction; the first light and the second light are not incident on the first apex of the transmissive optical element; projector.

6. the transmissive optical element further includes a first exit surface that is parallel to the first incident surface and through which the first light incident from the first incident surface exits, and a second exit surface that is parallel to the second incident surface and through which the second light incident from the second incident surface exits. The projector according to claim 5 .

7. the transmissive optical element has a front surface and a back surface that intersect with the rotation axis, and 2×m (m: a natural number equal to or greater than 2) side surfaces that are in contact with the front surface and the back surface, the first entrance surface and the first exit surface are two first side surfaces parallel to each other among the 2×m side surfaces, The second entrance surface and the second exit surface are two second side surfaces that are different from the first side surfaces of the 2×m side surfaces and are parallel to each other. The projector according to claim 1 or 6.

8. the optical scanning unit further includes a first light-shielding unit that is provided at an end of the first incident surface on the first apex side, an end of the second incident surface on the first apex side, and the first apex, and that blocks light incident from the light source unit. The projector according to claim 5 .

9. a width of the first light-shielding portion is equal to or greater than a width of the first light and the second light when emitted from the light source portion and incident on the transmissive optical element; The projector according to claim 8 .

10. the light source unit time-sequentially emits, in addition to the first light and the second light, a third light having a wavelength band different from that of the first light and the second light; the transmissive optical element further includes a third incident surface onto which the third light emitted from the light source unit is incident, and a second apex portion located at a boundary between the second incident surface and the third incident surface, the optical scanning unit further includes a second light-shielding unit that is provided at an end of the second incident surface on the second apex side, an end of the third incident surface on the second apex side, and the second apex, and that shields light incident from the light source unit; a width of the second light-shielding portion and a width of the first light-shielding portion are different from each other; The projector according to claim 8 or 9.

11. the light source unit periodically repeats an on state and an off state, a period during which the transmissive optical element makes one rotation includes a first period during which the first light emitted from the light source unit is incident on the first incident surface, a second period during which the second light emitted from the light source unit is incident on the second incident surface, and a third period between the first period and the second period, During the third period, the light source unit is turned off. The projector according to claim 5 .

12. a light source unit that time-sequentially emits a first light and a second light having a wavelength band different from that of the first light; a light scanning unit that scans an illuminated area with the first light and the second light that are incident from the light source unit in a time-sequential manner; a light modulation device disposed in the illumination area and modulating the light incident from the light scanning unit in accordance with image information; a projection optical device that projects the light modulated by the light modulation device; Equipped with The optical scanning unit a transmissive optical element including a first incident surface onto which the first light emitted from the light source unit is incident, a second incident surface that intersects with the first incident surface and onto which the second light emitted from the light source unit is incident, and a first apex portion located at a boundary between the first incident surface and the second incident surface, the first light and the second light are strip-shaped lights extending in a first direction, The transmitting optical element rotates around a rotation axis, scanning the first light incident on a first portion of the first incident surface and the second light incident on a second portion of the second incident surface in a second direction intersecting the first direction on a light modulation region of the light modulation device; the first light incident on a third portion of the first incident surface closer to the first apex than the first portion and the first apex, and the second light incident on a fourth portion of the second incident surface closer to the first apex than the second portion and the first apex are scanned in the second direction outside the light modulation area. projector.

Images