Light source device and projector

Abstract

To provide a light source device that can emit light with high parallelism, and a projector.SOLUTION: A light source device 10 comprises a first luminous element 11 that emits first light L1, a first optical element 13, a displacement direction changing element 17, and a second optical element 14. In the first optical element 13 and the second optical element 14, an incident surface and an emission surface are parallel to each other. The first optical element 13 rotates about a first rotation axis C1 along a Y-axis direction to displace an optical path of the first light L1 emitted from the first luminous element 11 in a Z-axis direction. The displacement direction changing element 17 changes the displacement direction of the optical path of the first light L1 emitted from the first optical element 13 from the Z-axis direction to the Y-axis direction. The second optical element 14 rotates about a second rotation axis C2 along the Y-axis direction to displace the optical path of the first light L1 emitted from the displacement direction changing element 17 in the Z-axis direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a light source device and a projector. [Background technology]

[0002] Patent Document 1 discloses a projector including 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. In this projector, the light source lamp emits light having a rectangular light beam cross section. The polygon mirror rotates and reflects the light emitted from the light source lamp, thereby scanning the light in the short side direction of the rectangular light beam cross section on the image formation area of ​​the liquid crystal light valve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-225956 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a polygon mirror is used for scanning light as in the projector of Patent Document 1, even if completely parallel light is incident on the polygon mirror, the parallelism of the light is lost due to the polygon mirror. That is, since the polygon mirror reflects light while rotating, the angle of incidence of the light on the reflecting surface of the polygon mirror changes over time, and the parallel light incident on the polygon mirror becomes light with a certain divergence angle and illuminates the liquid crystal light valve. As a result, there is a risk of problems related to the image quality of the projector, such as a decrease in contrast in the liquid crystal light valve. Therefore, there is a demand for a light source device that can stably emit light with a high degree of parallelism. [Means for solving the problem]

[0005] In order to solve the above problem, a light source device according to one aspect of the present invention includes a light source that emits a first light, a first optical element into which the first light emitted from the light source is incident and which transmits the incident first light, a displacement-direction changing element into which the first light emitted from the first optical element is incident and which transmits the incident first light, and a second optical element into which the first light emitted from the displacement-direction changing element is incident and which transmits the incident first light, wherein in the first optical element, a first entrance surface into which the first light is incident and a first exit surface from which the first light incident from the first entrance surface exits are parallel to each other, and in the second optical element, a second entrance surface into which the first light is incident and a second exit surface from which the first light incident from the first entrance surface exits are parallel to each other. and a second exit surface that exits the first light incident from the first optical element. The first optical element rotates around a first rotation axis along a second direction that intersects the first direction in which the first light emitted from the light source is incident on the first optical element, thereby displacing the optical path of the first light emitted from the light source in a third direction that intersects the first direction and the second direction. The displacement direction changing element changes the displacement direction of the optical path of the first light emitted from the first optical element from the third direction to the second direction. The second optical element rotates around a second rotation axis along the second direction, thereby displacing the optical path of the first light emitted from the displacement direction changing element in the third direction.

[0006] A projector according to one embodiment of the present invention comprises a light source device according to one embodiment of the present invention, a light modulation device that modulates the first light emitted from the light source device based on image information, and a projection optical device that projects the light modulated by the light modulation device. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic configuration diagram of a light source device according to a first embodiment. [Diagram 2] FIG. 1 is a perspective view of a light source device according to a first embodiment. [Figure 3A] 1A and 1B are schematic diagrams for explaining the behavior of light when a transmissive optical element rotates. [Figure 3B]FIG. 3B is a schematic diagram showing a continuation of FIG. 3A. [Figure 3C] FIG. 3C is a schematic diagram showing a continuation of FIG. 3B. [Figure 3D] FIG. 3D is a schematic diagram showing a continuation of FIG. 3C. [Figure 3E] FIG. 3B is a schematic diagram showing a continuation of FIG. 3D. [Figure 3F] FIG. 3B is a schematic diagram showing a continuation of FIG. 3E. [Figure 4] FIG. 11 is a schematic configuration diagram of a projector according to a second embodiment. [Figure 5A] 13 is a diagram showing the center of gravity when the first optical element and the second optical element have the same specific gravity. FIG. [Figure 5B] 13 is a diagram showing the center of gravity when the specific gravity of the first optical element is greater than the specific gravity of the second optical element. FIG. [Figure 6] FIG. 11 is a schematic configuration diagram of a projector according to a third embodiment. [Figure 7] FIG. 13 is a schematic configuration diagram of a projector according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [First embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The light source device 10 of this embodiment is an example of a light source device that uses a laser diode as a light emitting element. In the drawings, the dimensions of the components may be shown on different scales in order to make the components easier to see.

[0009] FIG. 1 is a schematic diagram of a light source device 10 of the present embodiment, and FIG. 2 is a perspective view showing the light source device 10. As shown in FIG. As shown in Figures 1 and 2, the light source device 10 of this embodiment includes a first light-emitting element 11, a first optical element 13, a second optical element 14, a first driving device 15, a second driving device 16, and a displacement direction changing element 17. As described below, the light source device 10 of this embodiment scans the light emitted from the first light-emitting element 11 in one direction with the first optical element 13, changes the scanning direction of the light scanned by the first optical element 13 so that the light is displaced in another direction perpendicular to the first direction by the displacement direction changing element 17, and scans the light scanned in the other direction again in the first direction with the second optical element 14, thereby scanning the light two-dimensionally.

[0010] Hereinafter, in each drawing, an XYZ orthogonal coordinate system is used for explanation as necessary. The X-axis is an axis parallel to the optical axis AX of the first light-emitting element 11. The optical axis AX of the first light-emitting element 11 is defined as an axis along the principal ray of the first light L1 emitted from the first light-emitting element 11. The traveling direction of the first light L1 is defined as the +X direction. The Y-axis is an axis perpendicular to the X-axis and is an axis along the first rotation axis C1 of the first optical element 13 and the second rotation axis C2 of the second optical element 14. The Z-axis is an axis perpendicular to the X-axis and the Y-axis. Note that the relationship between the X-axis, the Y-axis, and the Z-axis is not limited to being perpendicular, but may be any intersecting relationship. Hereinafter, the direction parallel to the X-axis is referred to as the X-axis direction, the direction parallel to the Y-axis is referred to as the Y-axis direction, and the direction parallel to the Z-axis is referred to as the Z-axis direction. In other words, the X-axis direction includes both the +X and -X directions, the Y-axis direction includes both the +Y and -Y directions, and the Z-axis direction includes both the +Z and -Z directions.

[0011] The first light emitting element 11 emits a first light L1 of a first wavelength band in the +X direction toward the first optical element 13. The first light emitting element 11 is composed of a laser diode. Therefore, the first light L1 emitted from the first light emitting element 11 is a linearly polarized light having coherence, a narrow beam width, and a high degree of parallelism. The first wavelength band is not particularly limited as long as it is within the visible light wavelength band. The first light emitting element 11 is an example of a light source.

[0012] The first optical element 13 is provided between the first light emitting element 11 and the displacement direction changing element 17 on the optical axis AX of the first light emitting element 11. The first optical element 13 receives the first light L1 emitted from the first light emitting element 11 in the +X direction and transmits the first light L1 incident thereon in the +X direction. The first optical element 13 is made of a rotatably supported light-transmitting member. The first optical element 13 is rotatable about a first rotation axis C1 extending along the Y-axis direction. The first rotation axis C1 is connected to a first driving device 15 including a motor or the like. The first optical element 13 rotates about the first rotation axis C1 by being driven by the first driving device 15.

[0013] The first optical element 13 is made of a light-transmitting material such as optical glass such as BK7, quartz, or resin. The first optical element 13 has a first surface 13a and a second surface 13b that intersect with the first rotation axis C1, and four first side surfaces 13c1, 13c2, 13c3, and 13c4 that are in contact with the first surface 13a and the second surface 13b perpendicularly. That is, the shape of the first optical element 13 is a regular rectangular prism having six planes including the first surface 13a, the second surface 13b, and the four first side surfaces 13c1, 13c2, 13c3, and 13c4. The cross-sectional shape of the first optical element 13 cut along a plane perpendicular to the first rotation axis C1 is a square. That is, the four first side surfaces 13c1, 13c2, 13c3, and 13c4 have the same area as one another, and one first side surface and another first side surface disposed on the opposite side to the one first side surface are parallel to one another.

[0014] The first optical element 13 transmits the first light L1 emitted from the first light emitting element 11 while rotating around the first rotation axis C1. Therefore, the first side surface on which the first light L1 emitted from the first light emitting element 11 enters the first optical element 13 is not determined to be one, but changes over time. Similarly, the first side surface on which the first light L1 incident on the first optical element 13 is emitted to the external space is not determined to be one, but changes over time. In the first optical element 13, the first side surface on which the first light L1 emitted from the first light emitting element 11 enters is referred to as the first incident surface. Also, the first side surface on which the first light L1 incident from the first incident surface exits is referred to as the first exit surface. In this case, the first entrance surface and the first exit surface change over time, the first entrance surface is one of the four first side surfaces 13c1, 13c2, 13c3, and 13c4, and the first exit surface is one of the first side surfaces arranged on the opposite side of the one first side surface that is the first entrance surface. In other words, the first entrance surface and the first exit surface are parallel to each other.

[0015] In this specification, when two surfaces of an optical element are said to be parallel to each other, the angle between the two surfaces is in the range of 0±5 degrees, taking into consideration the processing accuracy of the translucent member, the tolerance for the parallelism of light, etc.

[0016] In this embodiment, the first optical element 13 has four first side surfaces 13c1, 13c2, 13c3, and 13c4, but the number of first side surfaces does not necessarily have to be four, and is preferably 2×m (m is a natural number equal to or greater than 2). That is, the number of first side surfaces is preferably an even number, for example, six, eight, and the like. Furthermore, it is preferable that the number of first side surfaces is an even number, and that each of the first side surfaces is parallel to the first side surface opposite the first side surface. This reduces the generation of stray light in the first optical element 13, and improves the light utilization efficiency.

[0017] The displacement direction changing element 17 is disposed on the light emission side of the first optical element 13 on the optical axis AX of the first light emitting element 11. The displacement direction changing element 17 receives the first light L1 emitted from the first optical element 13 in the +X direction and transmits the incident first light L1 in the +X direction. The displacement direction changing element 17 is, for example, configured of a dove prism, which is a trapezoidal light-transmitting member, and is disposed so that its longitudinal direction is along the optical axis AX. The displacement direction changing element 17 receives the first light L1 emitted from the first optical element 13 and inverts the up-down direction of the image and emits the incident first light L1. When the displacement direction changing element 17 rotates around the longitudinal direction as an axis, it rotates the image by twice the angle. In this embodiment, the displacement direction changing element 17 rotates 45 degrees around the longitudinal direction as an axis. Therefore, the displacement direction changing element 17 rotates the incident light by 90 degrees and emits it. In FIG. 1, the rotation of the displacement direction changing element 17 is omitted for the sake of simplicity. The displacement direction changing element 17 is fixed to a holding member provided on the exterior housing of the projector or a base member (not shown) housed in the exterior housing. The holding member may be a groove provided in a case that houses the optical component. The displacement direction changing element 17 is not limited to a dove prism. Moreover, the displacement direction changing element 17 does not necessarily have to be composed of one optical component.

[0018] The second optical element 14 is provided on the optical axis AX of the first light emitting element 11 and on the optical path of the light emitted from the displacement direction changing element 17. The second optical element 14 receives the first light L1 emitted from the displacement direction changing element 17 in the +X direction and transmits the first light L1 incident thereon in the +X direction. The second optical element 14 is made of a rotatably supported light-transmitting member. The second optical element 14 is rotatable about a second rotation axis C2 extending along the Y-axis direction. That is, the first rotation axis C1 and the second rotation axis C2 extend in parallel to each other in a virtual plane perpendicular to the optical axis AX. The second rotation axis C2 is connected to a second driving device 16 consisting of a motor or the like. The second optical element 14 rotates about the second rotation axis C2 by being driven by the second driving device 16.

[0019] The light-transmitting member constituting the second optical element 14 is substantially the same as the light-transmitting member constituting the first optical element 13. As the light-transmitting member, a light-transmitting material such as optical glass such as BK7, quartz, resin, etc. is used. In particular, in the case of the second optical element 14, unlike the first optical element 13, the first light L1 is incident after being scanned in one direction by the first optical element 13, and therefore the light density is lower than that of the first light L1 at the time of being incident on the first optical element 13. Therefore, there is a higher possibility than in the first optical element 13 that a resin material having lower light resistance and heat resistance than glass, etc. can be used.

[0020] The second optical element 14 has a third surface 14a and a fourth surface 14b that intersect with the second rotation axis C2, and four second side surfaces 14c1, 14c2, 14c3, and 14c4 that are in contact with the third surface 14a and the fourth surface 14b perpendicularly. That is, the shape of the second optical element 14 is a regular rectangular prism having six planes including the third surface 14a, the fourth surface 14b, and the four second side surfaces 14c1, 14c2, 14c3, and 14c4. The cross-sectional shape of the second optical element 14 cut by a plane perpendicular to the second rotation axis C2 is a square. That is, the four second side surfaces 14c1, 14c2, 14c3, and 14c4 have the same area as each other, and one second side surface and another second side surface disposed on the opposite side of the one second side surface are parallel to each other.

[0021] The second optical element 14 transmits the first light L1 emitted from the displacement direction changing element 17 while rotating around the second rotation axis C2. Therefore, the second side surface through which the first light L1 emitted from the displacement direction changing element 17 enters the second optical element 14 is not determined to be one, but changes over time. Similarly, the second side surface through which the first light L1 incident on the second optical element 14 is emitted to the external space is not determined to be one, but changes over time. In the second optical element 14, the second side surface through which the first light L1 emitted from the displacement direction changing element 17 enters is referred to as the second entrance surface. Also, the second side surface through which the first light L1 incident from the second entrance surface exits is referred to as the second exit surface. In this case, the second entrance surface and the second exit surface change over time, the second entrance surface is one of the four second side surfaces 14c1, 14c2, 14c3, and 14c4, and the second exit surface is one second side surface located on the opposite side of the one second side surface that is the second entrance surface. That is, the second entrance surface and the second exit surface are parallel to each other.

[0022] In this embodiment, the second optical element 14 has four second side surfaces 14c1, 14c2, 14c3, and 14c4, but the number of second side surfaces does not necessarily have to be four, and is preferably 2×n (n is a natural number equal to or greater than 2). That is, the number of second side surfaces is preferably an even number, for example, six, eight, and the like. Furthermore, it is preferable that the number of second side surfaces is an even number, and that each of the second side surfaces is parallel to the second side surface opposite the second side surface. This reduces the generation of stray light in the second optical element 14, and improves the light utilization efficiency.

[0023] In this embodiment, the first optical element 13 and the second optical element 14 both have the shape of a regular rectangular prism, but as long as they have parallel entrance and exit surfaces, the first optical element 13 and the second optical element 14 may have different shapes.

[0024] In FIG. 1 and FIG. 2, the first optical element 13 is shown to be the same size as the second optical element 14, but since the first optical element 13 scans the first light L1 in the Z-axis direction but not in the Y-axis direction, as described later, the length of the side in the Y-axis direction may be smaller than the lengths of the sides in the X-axis direction and the Z-axis direction. That is, instead of the shape close to a cube shown in FIG. 1, the first optical element 13 may be a rectangular parallelepiped shape in which the length of the side in the Y-axis direction is shorter than the lengths of the sides in the X-axis direction and the Z-axis direction. This allows the first optical element 13 to be made thinner. In that case, the size of the second optical element 14 is larger than the size of the first optical element 13, but as described above, since the optical density of the incident light is low in the second optical element 14, a resin material can be used. If a resin material is used as the light-transmitting member, the second optical element 14 becomes lighter, and the second driving device 16 can be made smaller in size.

[0025] At least one of the first optical element 13 and the second optical element 14 may be made of quartz. In the first optical element 13 and the second optical element 14, as the amount of light passing through the light-transmitting member increases, the amount of light absorbed by the light-transmitting member increases, and thermal distortion may occur in the light-transmitting member. In this case, the polarization direction of the first light L1 emitted from the first light-emitting element 11 is disturbed, and the linearly polarized light incident on the light-transmitting member becomes elliptically polarized light and is emitted from the light-transmitting member. That is, even though a laser diode is used as the first light-emitting element 11, it may be necessary to use a polarizing plate to align the polarization direction. Therefore, in order to obtain the effect of the first light-emitting element 11 described above, it is desirable to use a light-transmitting member with a small Young's modulus and a small thermal expansion coefficient as a light-transmitting member with little thermal distortion, and it is desirable to use quartz as an example.

[0026] The following describes the behavior of the first light L1 when it passes through the first optical element 13 and the second optical element 14. Note that the action of the first optical element 13 and the action of the second optical element 14 are similar and only differ in direction, so the following description will be given with only the first optical element 13 illustrated.

[0027] 3A to 3F are schematic diagrams for explaining the behavior of the first light L1 when the first optical element 13 rotates. In this example, when viewed from the +Y side, the first optical element 13 is disposed such that the first rotation axis C1 intersects with the optical axis AX, and rotates clockwise around the first rotation axis C1. The attitude of the first optical element 13 changes sequentially from FIG. 3A to FIG. 3F with the passage of time.

[0028] 3A to 3F, the angle between the optical axis AX and a straight line M that is perpendicular to the first side surface 13c1 of the first optical element 13 and passes through the intersection of the first rotation axis C1 and the optical axis AX is defined as the rotation angle ω of the first optical element 13. In reality, the first light L1 has a predetermined light flux width in the Z-axis direction, but here, attention is focused on the behavior of the light ray L1a traveling on the optical axis AX. The light ray L1a coincides with the optical path of the first light L1.

[0029] 3A shows the initial state of the first optical element 13. That is, the first optical element 13 is not rotated, the straight line M overlaps with the optical axis AX, and the rotation angle ω is 0 degrees. In this case, the light ray L1a is perpendicularly incident on the first side surface 13c1, and therefore travels along the optical axis AX inside the first optical element 13 without being refracted at the first side surface 13c1. Next, the light ray L1a is perpendicularly incident on the first side surface 13c3 that is parallel to the first side surface 13c1. Therefore, the light ray L1a is emitted from the first optical element 13 without being refracted at the first side surface 13c3 either, and travels along the optical axis AX.

[0030] Next, as shown in FIG. 3B, when the rotation angle ω of the first optical element 13 becomes larger than that in FIG. 3A, the light ray L1a is incident on the first side surface 13c1 at an incident angle equal to the rotation angle ω. Therefore, the light ray L1a is refracted to the +Z side and travels inside the first optical element 13. Next, the light ray L1a is also incident on the first side surface 13c3 at a predetermined incident angle, so it is refracted at the first side surface 13c3 and is emitted from the first optical element 13. At this time, since the first side surface 13c1 and the first side surface 13c3 are parallel to each other, the refraction angle of the light ray L1a incident on the first side surface 13c1 and the incident angle of the light ray L1a on the first side surface 13c3 have the same absolute value but are opposite in sign. As a result, the refraction angle of the light ray L1a when it enters the first side surface 13c1 and the refraction angle when it exits from the first side surface 13c3 are offset, so that the angle of incidence of the light ray L1a with respect to the first side surface 13c1 and the angle of refraction of the light ray L1a exiting from the first side surface 13c3 become equal. As a result, the light ray L1a travels parallel to the optical axis AX at a position displaced by a displacement amount d in the +Z direction from the optical axis AX. As described above, the light ray L1a coincides with the optical path of the first light L1, so displacing the light ray L1a is equivalent to displacing the optical path of the first light L1.

[0031] Next, as shown in Fig. 3C, when the rotation angle ω of the first optical element 13 becomes larger than that of Fig. 3B, the angle of incidence of the light ray L1a becomes larger, and the angle of refraction becomes larger. Therefore, the displacement amount d of the light ray L1a from the optical axis AX becomes larger than that of Fig. 3B. In addition, the state in which the light ray L1a travels parallel to the optical axis AX is always maintained. When the rotation angle ω is between 0 degrees and 45 degrees, the displacement amount d in the +Z direction increases monotonically as the rotation angle ω increases.

[0032] Next, as shown in FIG. 3D, when the rotation angle ω of the first optical element 13 exceeds 45 degrees, the first incident surface on which the light ray L1a is incident changes from the first side surface 13c1 to the first side surface 13c2. At this time, the light ray L1a is refracted at the first side surface 13c2, but the refraction direction is different from that in the period up to FIG. 3C, and it is refracted to the -Z side. In addition, the first exit surface from which the light ray L1a is emitted also changes from the first side surface 13c3 to the first side surface 13c4, but since the first side surface 13c2 and the first side surface 13c4 are parallel to each other, the refraction angle of the light ray L1a when it is incident on the first side surface 13c2 and the refraction angle when it is emitted from the first side surface 13c4 cancel each other out, which is the same as in the period up to FIG. 3C. As a result, the light ray L1a travels parallel to the optical axis AX at a position displaced by a displacement amount d in the -Z direction from the optical axis AX.

[0033] Next, as shown in Fig. 3E, when the rotation angle ω of the first optical element 13 becomes larger than that of Fig. 3D, the angle of incidence of the light ray L1a becomes smaller, and the angle of refraction becomes smaller. Therefore, the displacement amount d of the light ray L1a from the optical axis AX becomes smaller than that of Fig. 3D. Thus, when the rotation angle ω is between 45 degrees and 90 degrees, the displacement amount d in the -Z direction decreases monotonically as the rotation angle ω increases.

[0034] Next, as shown in FIG. 3F, when the rotation angle ω of the first optical element 13 becomes 90 degrees, the first incident surface changes from the first side surface 13c1 in the initial state to the first side surface 13c2, but the behavior of the light ray L1a becomes the same as in the initial state shown in FIG. 3A.

[0035] In this way, if the first entrance surface and the first exit surface of the first optical element 13 are parallel to each other, the traveling direction of the light ray L1a does not change from the +X direction regardless of the rotation angle ω of the first optical element 13. On the other hand, the light ray L1a moves parallel to the Z axis direction perpendicular to the optical axis AX according to the change in the rotation angle ω. That is, when the rotation angle ω is 0 degrees, the displacement amount d of the light ray L1a is 0, and the displacement amount d increases in the +Z direction when the rotation angle ω is between 0 degrees and 45 degrees. That is, the first optical element 13 displaces the light ray L1a in the +Z direction by rotating around the first rotation axis C1. Then, at the moment when the rotation angle ω exceeds 45 degrees, the absolute value of the displacement amount d remains the same, and the direction of displacement becomes the -Z direction. That is, the first optical element 13 displaces the light ray L1a greatly in the -Z direction. Then, the displacement amount d in the -Z direction decreases when the rotation angle ω is between 45 degrees and 90 degrees, and when the rotation angle ω becomes 90 degrees, the displacement amount d becomes 0. During this process, the first optical element 13 displaces the light ray L1a in the +Z direction. After 90 degrees, the above behavior is repeated. Therefore, when the first optical element 13 rotates once, the displacement amount d of the light ray L1a repeats the above cycle four times. The displacement amount d of the light ray L1a can be appropriately set by adjusting parameters of the first optical element 13, such as the refractive index and size.

[0036] The light ray L1a emitted from the first optical element 13 is incident on the displacement direction changing element 17. As described above, the displacement direction changing element 17 rotates 45 degrees around the longitudinal direction as an axis, and therefore rotates the displacement direction of the light ray L1a displaced in the Z-axis direction by 90 degrees. That is, the displacement direction changing element 17 changes the displacement direction of the light ray L1a emitted from the first optical element 13 from the Z-axis direction to the Y-axis direction. The light ray L1a emitted from the displacement direction changing element 17 is incident on the second optical element 14 while being displaced in the Y-axis direction. The second optical element 14, like the first optical element 13, rotates around the second rotation axis C2 to scan the light ray L1a in the Z-axis direction. Specifically, the second optical element 14 displaces the light ray L1a in the +Z direction when the rotation angle ω is between 0 degrees and 45 degrees. Then, the moment the rotation angle ω exceeds 45 degrees, the light ray L1a is largely displaced in the -Z direction. Then, when the rotation angle ω is between 45 degrees and 90 degrees, the light ray L1a is displaced again in the +Z direction.

[0037] As described above, the light source device 10 includes the first optical element 13 that scans the first light L1 in one direction, the displacement direction changing element 17 that changes the displacement direction of the first light L1 so that the first light L1 scanned in one direction by the first optical element 13 is displaced in another orthogonal direction, and the second optical element 14 that scans the first light L1 emitted from the displacement direction changing element 17 and displaced in the other direction back to the original direction. Therefore, the first light L1 is displaced in two directions orthogonal to each other over time. Specifically, as shown in FIG. 1 and FIG. 2, the first light L1 emitted from the first light emitting element 11 is scanned in the Z-axis direction by the first optical element 13. Then, the displacement direction of the first light L1 displaced in the Z-axis direction is changed by the displacement direction changing element 17 so that it is displaced in the Y-axis direction. Furthermore, the first light L1 emitted from the displacement direction changing element 17 and displaced in the Y-axis direction is scanned in the Z-axis direction orthogonal to the Y-axis direction by the second optical element 14. As a result, the entire rectangular illumination area Q set as the illumination target is illuminated.

[0038] In this embodiment, the +X direction in which the first light L1 travels corresponds to the first direction, the +Y direction corresponds to the second direction, and the +Z direction corresponds to the third direction.

[0039] [Effects of the first embodiment] The light source device 10 of this embodiment includes a first light emitting element 11 that emits a first light L1, a first optical element 13 on which the first light L1 emitted from the first light emitting element 11 is incident and transmits the incident first light L1, a displacement-direction changing element 17 on which the first light L1 emitted from the first optical element 13 is incident and transmits the incident first light L1, and a second optical element 14 on which the first light L1 emitted from the displacement-direction changing element 17 is incident and transmits the incident first light L1. In the first optical element 13, a first entrance surface on which the first light L1 is incident and a first exit surface from which the first light L1 incident from the first entrance surface exits are parallel to each other. In the second optical element 14, a second entrance surface on which the first light L1 is incident and a second entrance surface The first optical element 13 is parallel to the second exit surface that emits the first light L1 incident thereon, and the first optical element 13 rotates around a first rotation axis C1 along the Y-axis direction that intersects the +X direction in which the first light L1 emitted from the first light-emitting element 11 is incident on the first optical element 13, thereby displacing the optical path of the first light L1 emitted from the first light-emitting element 11 in the Z-axis direction that intersects the X-axis and Y-axis directions, and the displacement direction changing element 17 changes the displacement direction of the optical path of the first light L1 emitted from the first optical element 13 from the Z-axis direction to the Y-axis direction, and the second optical element 14 rotates around a second rotation axis C2 along the Y-axis direction, thereby displacing the optical path of the first light L1 emitted from the displacement direction changing element 17 in the Z-axis direction.

[0040] According to the light source device 10 of this embodiment, the first optical element 13 and the second optical element 14 have translucency, and the entrance surface and exit surface of the first light L1 are parallel in each of the first optical element 13 and the second optical element 14, so that the amount of refraction occurring when the first light L1 enters each optical element and the amount of refraction occurring when the first light L1 exits cancel each other out. Therefore, the first light L1 is displaced in a direction perpendicular to the optical path of the first light L1 while maintaining a state parallel to the optical axis AX of the first light emitting element 11 as the first optical element 13 and the second optical element 14 rotate. This allows the first light L1 to always be perpendicularly incident on the illuminated surface. In other words, light with high parallelism can always be emitted.

[0041] Furthermore, when the light source device 10 of this embodiment is used in a projector, the first light L1 can always be incident perpendicularly on the light modulation device. This makes it possible to suppress the deterioration of brightness and contrast in the light modulation device, the occurrence of color unevenness, and the loss of light in the projection optical device, and to realize a projector with excellent display quality.

[0042] Furthermore, since light source device 10 of the present embodiment includes displacement-direction changing element 17, the direction along first rotation axis C1 and the direction along second rotation axis C2 can be made parallel to each other. That is, first driving device 15 and second driving device 16 can be disposed in the Y-axis direction with respect to first optical element 13 and second optical element 14, respectively, and thus it is possible to prevent light source device 10 from becoming large in the Z-axis direction.

[0043] In the light source device 10 of the present embodiment, the displacement-direction changing element 17 is a dove prism. According to this configuration, by using a dove prism as the displacement-direction changing element 17, the direction in which the first light L1 is displaced can be easily changed.

[0044] [Second embodiment] A second embodiment of the present invention will now be described with reference to FIG. FIG. 4 is a schematic configuration diagram of a projector 20 according to the present embodiment. In FIG. 4, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0045] 4, the projector 20 includes a light source device 40, a light modulation device 21, an exit-side polarizing plate 22, and a projection optical device 23. In this embodiment, the first optical element 18 included in the light source device 40 has a shorter length in the direction along the first rotation axis C1 than the first optical element 13 of the first embodiment.

[0046] The light source device 40 is different from the light source device 10 of the first embodiment in that it includes a bending optical system 41 arranged on the optical path between the first optical element 18 and the displacement direction changing element 17. The bending optical system 41 bends the optical path of the first light L1 emitted from the first optical element 18 in the +X direction to the -X direction opposite to the +X direction. The -X direction corresponds to the fourth direction. The bending optical system 41 includes a first reflecting mirror 42 that bends the optical path to the -Y direction by reflecting the first light L1 traveling in the +X direction, and a second reflecting mirror 43 that bends the optical path to the -X direction by reflecting the first light L1 emitted from the first reflecting mirror 42 and traveling in the -Y direction. In this embodiment, the bending optical system 41 is arranged on the optical path between the first optical element 18 and the displacement direction changing element 17, but is not limited thereto, and may be arranged on the optical path between the first optical element 18 and the second optical element 14. For example, it may be disposed in the optical path between the displacement direction changing element 17 and the second optical element 14 .

[0047] Total reflection mirrors that reflect all incident light are used as the first reflection mirror 42 and the second reflection mirror 43. However, without being limited to this, a mirror that reflects a desired amount of light in a specific wavelength band and transmits the remainder, or a dichroic mirror that transmits light in a specific wavelength band and transmits the rest may also be used.

[0048] In this embodiment, the first optical element 18 and the second optical element 14 are disposed in a position where they overlap when viewed from the direction along the Y axis. Furthermore, the first rotation axis C1 and the second rotation axis C2 are disposed so as to be located on the same straight line.

[0049] The light source device 40 of this embodiment has a third driving device 19 different from that of the first embodiment. The third driving device 19 rotates the first optical element 18 about the first rotation axis C1. The third driving device 19 also rotates the second optical element 14 about the second rotation axis C2. That is, since the first rotation axis C1 and the second rotation axis C2 are arranged on the same straight line, the third driving device 19 rotates the first optical element 18 and the second optical element 14 about the same straight line. The third driving device 19 is an example of a driving device.

[0050] The first optical element 18 is disposed on the +Y direction side of the third driving device 19, and the second optical element 14 is disposed on the -Y direction side of the third driving device 19, that is, on the opposite side to the +Y direction side.

[0051] In this embodiment, the first optical element 18 and the second optical element 14 are fixed to the drive shaft of the third drive device 19 with adhesive or the like. Specifically, the drive shaft of the third drive device 19 is exposed to both the +Y side and the -Y side, and the +Y side of the drive shaft is bonded to the first optical element 18 via a base (not shown), and the -Y side of the drive shaft is bonded to the second optical element 14 via a base (not shown). With this configuration, the member constituting the rotation shaft does not penetrate the inside of the optical element, so that the first light L1 is not interfered with by the member. Of course, this is not limited to this, and it is sufficient that the first optical element 18 and the second optical element 14 are connected so as to be rotatable. For example, the drive shaft of the third drive device 19 may have a columnar shaft portion extending in both the +Y direction and the -Y direction, and this shaft portion may be inserted into the first optical element 18 and the second optical element 14. In the case of the above configuration, when the shaft portion is made of a material that does not transmit light, such as metal, it is necessary to ensure that the shaft portion does not overlap the area of ​​each optical element through which light passes.

[0052] The first optical element 18 has a first end 18d1 connected to the third driving device 19 and a second end 18d2 opposite to the first end 18d1, and the second optical element 14 has a third end 14d1 connected to the third driving device 19 and a fourth end 14d2 opposite to the third end 14d1. The length in the Y-axis direction from the first end 18d1 to the second end 18d2 of the first optical element 18 is shorter than the length in the Y-axis direction from the third end 14d1 to the fourth end 14d2 of the second optical element 14. That is, the first optical element 18 of this embodiment has a shorter length in the Y-axis direction than the second optical element 14.

[0053] In other words, the first optical element 18 has a first surface and a second surface intersecting the first rotation axis C1, and 2×m (m is a natural number of 2 or more) first side surfaces tangent to the first and second surfaces, and the first entrance surface into which the first light L1 is incident and the first exit surface from which the first light L1 exits are two first side surfaces parallel to each other among the 2×m first side surfaces. The second optical element 14 has a third surface and a fourth surface intersecting the second rotation axis C2, and The second entrance surface into which the first light L1 is incident and the second exit surface from which the first light L1 exits are two second side surfaces that are parallel to each other among the 2×n second side surfaces, the first surface faces the third driving device 19, and the third surface faces the third driving device 19, and the length in the Y-axis direction from the first surface to the second surface is configured to be shorter than the length in the Y-axis direction from the third surface to the fourth surface.

[0054] Furthermore, in this embodiment, the first optical element 18 is configured to have a larger specific gravity than the second optical element 14. The above configuration can be realized by, for example, using a material for the first optical element 18 that has a larger specific gravity than the material for the second optical element 14. In this case, even if different materials are used, it is preferable to use materials that have similar refractive indices.

[0055] FIG. 5A shows a first optical element 18h, a second optical element 14h, and a driving device 19h as a comparative example. The specific gravity of the first optical element 18h of the comparative example is equal to the specific gravity of the second optical element 14h. Therefore, the positions of the center of gravity G of the first optical element 18h, the second optical element 14h, and the driving device 19h are closer to the second optical element 14h, which has a larger volume. In contrast, in the light source device 40 of the present embodiment, the specific gravity of the first optical element 18 is configured to be larger than the specific gravity of the second optical element 14, so that the positions of the center of gravity G of the first optical element 18, the second optical element 14, and the third driving device 19 can be closer to the center of the third driving device 19, as shown in FIG. 5B.

[0056] The light modulation device 21 is provided on the light emission side of the light source device 40 on the optical axis AX. The light modulation device 21 modulates the first light L1 emitted from the light source device 40 according to image information to form image light. A transmissive liquid crystal panel is used for the light modulation device 21. The liquid crystal panel may or may not have a color filter. When the liquid crystal panel has a color filter, the projector 20 capable of color display can be realized. When the liquid crystal panel does not have a color filter, the projector 20 capable of monochrome display can be realized. Although not shown, color separation may be performed in a later stage and light may be irradiated onto a plurality of liquid crystal panels to generate image light. The driving method of the liquid crystal panel is not particularly limited, and may be a twisted nematic (TN) method, a vertical alignment (VA) method, an in-plane switching (IPS) method, or the like.

[0057] The exit-side polarizing plate 22 is provided on the optical axis AX between the light modulation device 21 and the projection optical device 23. The exit-side polarizing plate 22 transmits linearly polarized light in a specific direction exiting from the light modulation device 21 toward the projection optical device 23. An entrance-side polarizing plate may be disposed on the entrance side of the light modulation device 21. However, in the case of this embodiment, since a laser diode that emits linearly polarized light is used as the first light-emitting element 11, the entrance-side polarizing plate can be omitted.

[0058] The projection optical device 23 is composed of a plurality of projection lenses. The projection optical device 23 enlarges and projects the image light modulated by the light modulation device 21 onto a projection surface (not shown), such as a screen. As a result, an image is displayed on the projection surface.

[0059] However, without being limited to the above configuration, the length in the Y-axis direction from the first end 18d1 to the second end 18d2 of the first optical element 18 may be the same as the length in the Y-axis direction from the third end 14d1 to the fourth end 14d2 of the second optical element 14. In other words, the first optical element 18 and the second optical element 14 may have the same length in the Y-axis direction. Furthermore, the first optical element 18 and the second optical element 14 may have the same shape.

[0060] In other words, the first optical element 18 has a first surface and a second surface intersecting the first rotation axis C1, and 2×m (m is a natural number of 2 or more) first side surfaces tangent to the first surface and the second surface, and the first entrance surface into which the first light L1 is incident and the first exit surface from which the first light L1 exits are two first side surfaces parallel to each other among the 2×m first side surfaces, and the second optical element 14 has a third surface and a fourth surface intersecting the second rotation axis C2, and 2×m (m is a natural number of 2 or more) first side surfaces tangent to the third surface and the fourth surface. The second entrance surface into which the first light L1 is incident and the second exit surface from which the first light L1 exits are two second side surfaces that are parallel to each other among the 2×n second side surfaces, the first surface faces the third driving device 19, the third surface faces the third driving device 19, and the length from the first surface to the second surface in the Y-axis direction may be configured to be the same as the length from the third surface to the fourth surface in the Y-axis direction.

[0061] [Effects of the second embodiment] The projector 20 of this embodiment includes a light source device 40 including a first optical element 18, a bending optical system 41, a displacement direction changing element 17, and a second optical element 14, and therefore, similarly to the first embodiment, the first light L1 emitted from the light source device 40 can be made to always be perpendicularly incident on the light modulation device 21. As a result, deterioration of brightness and contrast in the light modulation device 21, occurrence of color unevenness, loss of light in the projection optical device 23, etc. are suppressed, and a projector 20 with excellent display quality can be realized.

[0062] According to the light source device 40 of the present embodiment, it is possible to illuminate in a substantially rectangular shape without using an optical system for shaping light into a rectangular shape, such as a multi-lens. Therefore, it is possible to relatively shorten the overall optical path length, and by reducing the number of optical components, it is possible to reduce the number of interfaces between the optical system and air, thereby reducing the loss of light due to interface reflection and improving the light utilization efficiency.

[0063] Since the light source device 40 of the present embodiment is a scanning type illumination device, it is also possible to turn off the first light emitting element 11 when the first light L1 reaches an area in the light modulation area of ​​the light modulation device 21 where black is to be displayed. This enables a method of illuminating only areas other than the black display area, that is, so-called area illumination, and can sufficiently improve the efficiency of the emitted light intensity relative to the input power compared to the conventional non-scanning type illumination method. Accordingly, the light absorbed by the emission side polarizing plate 22 during black display is reduced, and the load on the emission side polarizing plate 22 can be reduced. This can be expected to improve the reliability of the emission side polarizing plate 22 and improve the contrast by adopting a polarizing plate made of an organic material.

[0064] The light source device 40 of the present embodiment further includes a bending optical system 41 that is disposed on the optical path between the first optical element 18 and the second optical element 14 and bends the optical path of the first light L1 emitted from the first optical element 18 in the -X direction opposite to the +X direction. With this configuration, the apparent optical path length of the light source device 40 in the X-axis direction can be partially shortened, thereby preventing the light source device 40 from becoming large in size in the X-axis direction.

[0065] In the light source device 40 of the present embodiment, the first rotation axis C1 of the first optical element 18 and the second rotation axis C2 of the second optical element 14 are arranged on a straight line. That is, the first rotation axis C1 and the second rotation axis C2 are arranged on the same straight line. With this configuration, it is possible to suppress an increase in size due to a shift between the first optical element 18 and the second optical element 14 in a direction intersecting the first rotation axis C1, and this contributes to an efficient miniaturization of the light source device 40.

[0066] The light source device 40 of this embodiment includes a third drive device 19 that rotates the first optical element 18 around the first rotation axis C1, and the third drive device 19 rotates the second optical element 14 around the second rotation axis C2. With this configuration, the first optical element 18 and the second optical element 14 are rotated by the same third drive device 19, so the number of parts can be reduced compared to the case where two drive devices are provided to rotate the first optical element 18 and the second optical element 14, respectively. In addition, the drive device is shared by the first optical element 18 and the second optical element 14, which contributes to power saving. Furthermore, since the first optical element 18 and the second optical element 14 are rotated by the same third drive device 19, it is not necessary to synchronize the timing of rotation of the first optical element 18 and the second optical element 14 using another control unit or the like, and the structure of the light source device 40 can be prevented from becoming complicated.

[0067] In the light source device 40 of this embodiment, the first light L1 is incident on the second optical element 14 while being displaced in the Y-axis direction, while the first light L1 is incident on the first optical element 18 without being displaced in either direction. That is, in the Y-axis direction, the incident area of ​​the first light L1 incident on the first optical element 18 is narrower than the incident area of ​​the first light L1 incident on the second optical element 14. Therefore, in the light source device 40 of this embodiment, the first optical element 18 has a first end 18d1 connected to the third driving device 19 and a second end 18d2 opposite to the first end 18d1, the second optical element 14 has a third end 14d1 connected to the third driving device 19 and a fourth end 14d2 opposite to the third end 14d1, and the length in the Y-axis direction from the first end 18d1 to the second end 18d2 is shorter than the length in the Y-axis direction from the third end 14d1 to the fourth end 14d2. According to this configuration, the volume required for arranging the first optical element 18 is small, which contributes to efficient miniaturization of the light source device 40.

[0068] However, the present invention is not limited to the above configuration, and the length in the Y-axis direction from the first end 18d1 to the second end 18d2 may be the same as the length in the Y-axis direction from the third end 14d1 to the fourth end 14d2. In other words, the first optical element 18 and the second optical element 14 may have the same shape. According to this configuration, the first optical element 18 and the second optical element 14 can share parts, so that the manufacturing cost can be reduced. In addition, the center of gravity G of the first optical element 18, the second optical element 14, and the third driving device 19 can be brought closer to the center of the third driving device 19, so that the rotation of the first optical element 18 and the second optical element 14 can be stabilized.

[0069] In the light source device 40 of the present embodiment, the first optical element 18 is disposed on the +Y side of the third driving device 19, and the second optical element 14 is disposed on the -Y side opposite to the +Y side of the third driving device 19, and the specific gravity of the first optical element 18 is greater than that of the second optical element 14. With this configuration, the specific gravity of the first optical element 18, which is shorter in length in the Y-axis direction than the second optical element 14, is increased, thereby making it possible to increase the weight of the first optical element 18, which tends to be lighter than the second optical element 14. For this reason, the center of gravity G of the first optical element 18, the second optical element 14, and the third driving device 19 can be brought closer to the center of the third driving device 19, and the rotation of the first optical element 18 and the second optical element 14 can be stabilized.

[0070] [Third embodiment] Hereinafter, a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a schematic configuration diagram of a projector 30 according to the third embodiment. In FIG. 6, the same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0071] As shown in Fig. 6, the projector 30 includes a light source device 60, a light modulation device 21, an exit-side polarizing plate 22, and a projection optical device 23. The light source device 60 of this embodiment differs from the light source device 40 of the second embodiment in that it includes a blade portion 25. The other configuration is the same as in the second embodiment. Note that, also in the light source device 60 of this embodiment, the first optical element 18 is disposed on the +Y direction side of the third driving device 19, and the second optical element 14 is disposed on the -Y direction side of the third driving device 19, i.e., on the opposite side to the +Y direction side.

[0072] The light source device 60 has a blade portion 25 connected to the first optical element 18. The blade portion 25 circulates air to a heat generating body that generates heat, such as a heat sink (not shown) connected to the first light emitting element 11 and the optical modulation device 21. In this embodiment, the blade portion 25 is adhered to the first optical element 18 with an adhesive via a base (not shown). This is not limiting, and the blade portion 25 may be connected to the first optical element 18 so as to rotate together with the first optical element 18. For example, the shaft portion inserted into the first optical element 18 may be fixed to the approximate center of the blade portion 25 to connect them to each other.

[0073] Blade portion 25 is connected to the +Y side of first optical element 18. That is, third driving device 19 rotates blade portion 25 together with first optical element 18. In other words, third driving device 19 serves as a driving source for both first optical element 18 and blade portion 25. Blade portion 25 is housed in case 26 having an intake port and an exhaust port (not shown).

[0074] Also in this embodiment, the first optical element 18 has a shorter length in the Y-axis direction than the second optical element 14. That is, the length in the Y-axis direction from the first end 18d1 to the second end 18d2 of the first optical element 18 is shorter than the length in the Y-axis direction from the third end 14d1 to the fourth end 14d2 of the second optical element 14. Moreover, the specific gravity of the first optical element 18 and the specific gravity of the second optical element 14 are the same or approximately the same.

[0075] As shown in FIG. 6, even if the length of the first optical element 18 in the Y-axis direction is shorter than the length of the second optical element 14, by connecting the wing portion 25 to the first optical element 18, which is lighter than the second optical element 14, the center of gravity G of the first optical element 18, the second optical element 14 and the third driving device 19 can be brought closer to the center of the third driving device 19.

[0076] Case 26 contributes to adjusting the flow direction of the airflow generated by rotating blade portion 25. The airflow discharged from the exhaust port of case 26 is transported to the heat generating element. Case 26 is also fixed to the exterior housing of projector 30. Fixed to the exterior housing does not necessarily mean directly fixed to a housing exposed to the outside, but also includes being fixed to the exterior housing exposed to the outside via sheet metal or the like.

[0077] [Effects of the third embodiment] The projector 30 of this embodiment includes a light source device 60 including a first optical element 18, a bending optical system 41, a displacement direction changing element 17, and a second optical element 14, and therefore, similarly to the second embodiment, the first light L1 emitted from the light source device 60 can be made to always be perpendicularly incident on the light modulation device 21. As a result, deterioration of brightness and contrast in the light modulation device 21, occurrence of color unevenness, loss of light in the projection optical device 23, etc. are suppressed, and a projector 30 with excellent display quality can be realized.

[0078] According to the light source device 60 of this embodiment, it is possible to illuminate in a substantially rectangular shape without using an optical system for shaping light into a rectangular shape, such as a multi-lens. Therefore, it is possible to relatively shorten the overall optical path length, and by reducing the number of optical components, it is possible to reduce the number of interfaces between the optical system and air, thereby reducing the loss of light due to interface reflection and improving the light utilization efficiency.

[0079] Furthermore, in the light source device 60 of this embodiment, the first optical element 18 is arranged on the +Y side of the third driving device 19, the second optical element 14 is arranged on the -Y side opposite the +Y side of the third driving device 19, and a blade portion 25 that circulates air to a heating element that generates heat is connected to the first optical element 18.

[0080] According to this configuration, by connecting the wing portions 25 to the first optical element 18, which is shorter in length in the Y-axis direction than the second optical element 14, it is possible to increase the weight of the first optical element 18, which tends to be lighter than the second optical element 14. Therefore, the center of gravity G of the first optical element 18, the second optical element 14, and the third drive device 19 can be brought closer to the center of the third drive device 19, and the rotation of the first optical element 18 and the second optical element 14 can be stabilized. Also, by attaching the wing portions 25, the rotation of the first optical element 18 can also serve to cool the heat generating body.

[0081] [Fourth embodiment] A fourth embodiment of the present invention will be described below with reference to FIG. FIG. 7 is a schematic configuration diagram of a projector 50 according to the fourth embodiment. In FIG. 7, components common to the above-described embodiment are given the same reference numerals, and description thereof will be omitted.

[0082] 7, the projector 50 includes a light source device 70, a light modulation device 21, an exit-side polarizing plate 22, and a projection optical device 23. The light source device 70 of the present embodiment differs from the light source device 40 of the second embodiment in that it includes a light flux width adjustment optical system 71. The other configurations are the same as those of the second embodiment.

[0083] The light beam width adjustment optical system 71 is provided between the first optical element 18 and the bending optical system 41. The light beam width adjustment optical system 71 is composed of one concave lens 72 and one convex lens 73, but the type and number of lenses are not particularly limited. The light beam width adjustment optical system 71 adjusts the light beam width of the light emitted from the first optical element 18. The light beam width adjustment optical system 71 of this embodiment is an optical system that emits parallel light incident on the light beam width adjustment optical system 71 as parallel light with an adjusted light beam width, that is, a so-called afocal optical system.

[0084] In this embodiment, the light beam width adjustment optical system 71 is arranged between the first optical element 18 and the bending optical system 41, but is not limited to the above configuration and may be arranged between the first optical element 18 and the first light-emitting element 11, or between the second optical element 14 and the bending optical system 41.

[0085] [Effects of the fourth embodiment] The projector 50 of the present embodiment includes a light source device 70 including a first optical element 18, a bending optical system 41, a displacement direction changing element 17, and a second optical element 14, and therefore, similarly to the second embodiment, the first light L1 emitted from the light source device 70 can be made to always be perpendicularly incident on the light modulation device 21. As a result, a decrease in brightness and contrast in the light modulation device 21, the occurrence of color unevenness, light loss in the projection optical device 23, and the like are suppressed, and a projector 50 with excellent display quality can be realized.

[0086] According to the light source device 70 of the present embodiment, it is possible to illuminate in a substantially rectangular shape without using an optical system for shaping light into a rectangular shape, such as a multi-lens. Therefore, it is possible to relatively shorten the overall optical path length, and by reducing the number of optical components, it is possible to reduce the number of interfaces between the optical system and air, thereby reducing the loss of light due to interface reflection and improving the light utilization efficiency.

[0087] Particularly in the case of this embodiment, by adjusting the sizes of the first optical element 18 and the second optical element 14 of the light source device 70 or the magnification of the light flux width adjustment optical system 71, it is possible to easily match the illuminated area Q of the first light L1 with the light modulation area of ​​the light modulation device 21. Furthermore, since the first light L1 having a rectangular cross-sectional shape is emitted in parallel from the light source device 70, the existing optical system of the projector can be used as the optical system subsequent to the light source device 70, and there is no need to design a new optical system.

[0088] 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, one aspect of the present invention can be a configuration in which the characteristic portions of the above-described embodiments are appropriately combined.

[0089] In the light source device of the above embodiment, the shape of each optical element is an example of a polygonal prism with an even number of side faces. From the viewpoint of less generation of stray light and high light utilization efficiency, a polygonal prism with an even number of side faces is desirable. However, as long as it has at least one pair of parallel entrance and exit surfaces, the shape may be other than a polygonal prism with an even number of side faces. In addition, the "rotation" in each of the above embodiments may also include swinging the optical element to perform a similar scan.

[0090] In addition, the specific description of the shape, number, arrangement, material, etc. of each component of the light source device and the projector is not limited to the above embodiment and can be changed as appropriate. Also, in the above embodiment, an example in which the light source device according to the present invention is mounted on a projector using a liquid crystal panel is shown, but this is not limiting. The light source device according to the present invention may be applied to a projector using a digital micromirror device as a light modulation device.

[0091] In the above embodiment, the light source device of the present invention is applied to a projector, but the present invention is not limited to this. The light source device of the present invention can also be applied to lighting fixtures, automobile headlights, and the like.

[0092] [Summary of this disclosure] The following is a summary of this disclosure.

[0093] (Appendix 1) A light source that emits a first light; a first optical element onto which the first light emitted from the light source is incident and which transmits the incident first light; a displacement direction changing element onto which the first light emitted from the first optical element is incident and which transmits the incident first light; a second optical element into which the first light emitted from the displacement direction changing element is incident and which transmits the incident first light, In the first optical element, a first entrance surface into which the first light is incident and a first exit surface from which the first light incident from the first entrance surface exits are parallel to each other, In the second optical element, a second entrance surface into which the first light is incident and a second exit surface from which the first light incident from the second entrance surface exits are parallel to each other, the first optical element rotates about a first rotation axis along a second direction intersecting a first direction in which the first light emitted from the light source is incident on the first optical element, thereby displacing an optical path of the first light emitted from the light source in a third direction intersecting the first direction and the second direction; the displacement direction changing element changes a displacement direction of an optical path of the first light emitted from the first optical element from the third direction to the second direction, A light source device in which the second optical element rotates about a second rotation axis along the second direction, thereby displacing the optical path of the first light emitted from the displacement direction changing element in the third direction.

[0094] According to the configuration of Supplementary Note 1, the first optical element and the second optical element have light transmissivity, and the entrance surface and exit surface of the first light are parallel in each of the first optical element and the second optical element, so that the amount of refraction occurring when the first light enters each optical element and the amount of refraction occurring when the first light exits cancel each other out. Therefore, the first light is displaced in a direction perpendicular to the optical path of the first light while maintaining a state parallel to the optical axis of the first light emitting element as the first optical element and the second optical element rotate. This allows the first light to always be perpendicularly incident on the illuminated surface. In other words, light with high parallelism can always be exited.

[0095] (Appendix 2) 2. The light source device of claim 1, wherein the displacement direction changing element is a dove prism.

[0096] According to the configuration of Supplementary Note 2, by using a dove prism as the displacement direction changing element, the direction in which the first light is displaced can be easily changed.

[0097] (Appendix 3) The light source device described in Appendix 1 or Appendix 2, further comprising a bending optical system arranged on an optical path between the first optical element and the second optical element, bending the optical path of the first light emitted from the first optical element in a fourth direction opposite to the first direction.

[0098] According to the configuration of Appendix 3, the optical path of the light is bent in a fourth direction opposite to the first direction, so that the apparent optical path length of the light source device in the first direction can be shortened in part, thereby preventing the light source device from becoming larger in size in the first direction.

[0099] (Appendix 4) 4. The light source device according to claim 3, wherein the first rotation axis and the second rotation axis are arranged on the same straight line.

[0100] According to the configuration of Appendix 4, the first rotation axis and the second rotation axis are arranged on the same straight line, so that it is possible to suppress an increase in size due to misalignment of the first optical element and the second optical element in a direction intersecting the first rotation axis, and this contributes to efficient miniaturization of the light source device.

[0101] (Appendix 5) a drive device that rotates the first optical element about the first rotation axis; 5. The light source device according to claim 3, wherein the driving device rotates the second optical element around the second rotation axis.

[0102] According to the configuration of Supplementary Note 5, by rotating the first optical element and the second optical element by the same driving device, the number of parts can be reduced compared to the case where two driving devices are provided to rotate the first optical element and the second optical element, respectively. In addition, by using the same driving device for both the first optical element and the second optical element, it contributes to power saving. Furthermore, since the first optical element and the second optical element are rotated by the same driving device, it is not necessary to synchronize the timing of the rotation of the first optical element and the second optical element using another control unit, etc., and the structure of the light source device can be prevented from becoming complicated.

[0103] (Appendix 6) the first optical element has a first end connected to the driving device and a second end opposite the first end, the second optical element has a third end connected to the driving device and a fourth end opposite the third end, The light source device of claim 5, wherein a length in the second direction from the first end to the second end is shorter than a length in the second direction from the third end to the fourth end.

[0104] According to the configuration of Supplementary Note 6, the volume required for arranging the first optical element is small, which contributes to efficient miniaturization of the light source device.

[0105] (Appendix 7) the first optical element is disposed on a second direction side of the driving device, the second optical element is disposed on a side opposite to the second direction side of the driving device, 7. The light source device according to claim 6, wherein the first optical element has a specific gravity greater than the second optical element.

[0106] According to the configuration of Supplementary Note 7, by increasing the specific gravity of the first optical element, which is shorter in the second direction than the second optical element, it is possible to increase the weight of the first optical element, which tends to be lighter than the second optical element. This allows the centers of gravity of the first optical element, the second optical element, and the drive device to be closer to the center of the drive device, and the rotation of the first optical element and the second optical element can be stabilized.

[0107] (Appendix 8) the first optical element is disposed on a side of the driving device in the second direction, the second optical element is disposed on a side opposite to the second direction side of the driving device, The light source device according to any one of claims 5 to 7, wherein a blade portion that circulates air to a heat generating body that generates heat is connected to the first optical element.

[0108] According to the configuration of Supplementary Note 8, by connecting the wing portion to the first optical element, which is shorter in the second direction than the second optical element, the weight of the first optical element, which tends to be lighter than the second optical element, can be increased. Therefore, the centers of gravity of the first optical element, the second optical element, and the drive device can be brought closer to the center of the drive device, and the rotation of the first optical element and the second optical element can be stabilized. In addition, by attaching the wing portion, the rotation of the first optical element can also serve to cool the heat generating body.

[0109] (Appendix 9) the first optical element has a first end connected to the driving device and a second end opposite the first end, the second optical element has a third end connected to the driving device and a fourth end opposite the third end, The light source device of claim 5, wherein the length in the second direction from the first end to the second end is the same as the length in the second direction from the third end to the fourth end.

[0110] According to the configuration of Supplementary Note 9, the first optical element and the second optical element can share parts, thereby reducing manufacturing costs. Also, the centers of gravity of the first optical element, the second optical element, and the driving device can be brought closer to the center of the driving device, thereby stabilizing the rotation of the first optical element and the second optical element by the driving device.

[0111] (Appendix 10) A light source device according to any one of Supplementary Note 1 to Supplementary Note 9; a light modulation device that modulates the first light emitted from the light source device based on image information; a projection optical device that projects the light modulated by the light modulation device; A projector equipped with

[0112] According to the configuration of Appendix 10, the first light emitted from the light source device always enters the light modulation device perpendicularly, thereby suppressing the decrease in brightness and contrast in the light modulation device, the occurrence of color unevenness, and the loss of light in the projection optical device, and thus realizing a projector with excellent display quality. [Explanation of symbols]

[0113] 10, 40, 60, 70...light source device, 11...first light emitting element, 13...first optical element, 13a...first surface, 13b...second surface, 13c1, 13c2, 13c3, 13c4...first side surface, 14...second optical element, 14a...third surface, 14b...fourth surface, 14c1, 14c2, 14c3, 14c4...second side surface, 14d1...third end, 14d2...fourth end, 15...first drive device, 16...second drive device, 17...displacement direction changing element, 18...first optical element, 18d1...first end, 18d2...second end, 19...third drive device, 20,30,50...projector, 21...light modulation device, 22...output side polarizing plate, 23...projection optical device, 25...blade portion, 26...case, 41...bending optical system, 42...first reflecting mirror, 43...second reflecting mirror, 71...light beam width adjustment optical system, 72...concave lens, 73...convex lens, AX...optical axis, C1...first rotation axis, C2...second rotation axis, G...center of gravity, L1...first light, L1a...light ray, M...straight line, Q...illuminated area, d...displacement amount.

Claims

1. A light source that emits a first light; a first optical element on which the first light emitted from the light source is incident and which transmits the incident first light; a displacement direction changing element onto which the first light emitted from the first optical element is incident and which transmits the incident first light; a second optical element into which the first light emitted from the displacement direction changing element is incident and which transmits the incident first light, In the first optical element, a first entrance surface into which the first light is incident and a first exit surface from which the first light incident from the first entrance surface exits are parallel to each other, In the second optical element, a second entrance surface into which the first light is incident and a second exit surface from which the first light incident from the second entrance surface exits are parallel to each other, the first optical element rotates about a first rotation axis along a second direction intersecting a first direction in which the first light emitted from the light source is incident on the first optical element, thereby displacing an optical path of the first light emitted from the light source in a third direction intersecting the first direction and the second direction; the displacement direction changing element changes a displacement direction of an optical path of the first light emitted from the first optical element from the third direction to the second direction, A light source device in which the second optical element rotates around a second rotation axis along the second direction, thereby displacing the optical path of the first light emitted from the displacement direction changing element in the third direction.

2. The light source device according to claim 1 , wherein the displacement direction changing element is a dove prism.

3. 3. The light source device according to claim 1, further comprising a bending optical system arranged on an optical path between the first optical element and the second optical element, bending the optical path of the first light emitted from the first optical element in a fourth direction opposite to the first direction.

4. The method according to claim 3 , wherein the first rotation axis and the second rotation axis are arranged on a same straight line. Light source device.

5. a drive device that rotates the first optical element about the first rotation axis; The light source device according to claim 4 , wherein the drive device rotates the second optical element about the second rotation axis.

6. the first optical element has a first end connected to the driving device and a second end opposite the first end, the second optical element has a third end connected to the driving device and a fourth end opposite the third end, The light source device according to claim 5 , wherein a length in the second direction from the first end to the second end is shorter than a length in the second direction from the third end to the fourth end.

7. the first optical element is disposed on a side of the driving device in the second direction, the second optical element is disposed on a side opposite to the second direction side of the driving device, The light source device according to claim 6 , wherein the specific gravity of the first optical element is greater than the specific gravity of the second optical element.

8. the first optical element is disposed on a side of the driving device in the second direction, the second optical element is disposed on a side opposite to the second direction side of the driving device, The light source device according to claim 6 , wherein a vane portion for circulating air to a heat generating body that generates heat is connected to the first optical element.

9. the first optical element has a first end connected to the driving device and a second end opposite the first end, the second optical element has a third end connected to the driving device and a fourth end opposite the third end, The light source device according to claim 5 , wherein a length in the second direction from the first end to the second end is the same as a length in the second direction from the third end to the fourth end.

10. The light source device according to claim 1 or 2, a light modulation device that modulates the first light emitted from the light source device based on image information; a projection optical device that projects the light modulated by the light modulation device; A projector equipped with

Images