Light source device, method for manufacturing a light source device, and projector

Abstract

The present invention provides a light source device capable of suppressing axial wobble, a method for manufacturing the light source device, and a projector. [Solution] The light source device of the present invention comprises a light source unit and an optical scanning unit, the optical scanning unit having a transmissive optical element that rotates about a rotation axis and a drive unit that rotates the transmissive optical element. The drive unit has a rotation fixing unit that fixes the transmissive optical element and a plurality of positioning pins arranged on the support surface of the rotation fixing unit and located on the same circle centered on the rotation axis. The plurality of positioning pins include a first pin that abuts the first side surface of the transmissive optical element, a second pin that abuts the second side surface of the transmissive optical element, and a third pin that abuts the third side surface of the transmissive optical element. In a cross-sectional view with respect to a plane perpendicular to the rotation axis, when the intersection points between the center of the transmissive optical element and each side surface are defined as the first intersection, second intersection, and third intersection, the positions of the first intersection with respect to the first pin, the second intersection with respect to the second pin, and the third intersection with respect to the third pin are shifted to one side in the circumferential direction of the rotation axis.

Description

Technical Field

[0001] The present invention relates to a light source device, a method for manufacturing the light source device, and a projector.

Background Art

[0002] As a light source device used in a projector, there has been proposed a light source device that illuminates a light modulation device by temporally scanning light emitted from a light emitting element on the light modulation device such as a liquid crystal panel.

[0003] Patent Document 1 below discloses a projector including an illumination device that emits an illumination light beam, a liquid crystal panel that modulates the illumination light beam from the illumination device according to image information, a projection optical system that projects the light beam modulated by the liquid crystal panel, and a rotating prism provided between the illumination device and the liquid crystal panel. In this projector, the rotating prism scans the light emitted from the illumination device by a transmissive optical element that rotates by a motor. The light scanned by the rotating prism is modulated by the liquid crystal panel and projected onto a screen.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the rotating prism of the above projector, it is difficult to accurately align the rotation axis of the motor and the central axis of the transmissive optical element, and there is a risk of noise and vibration due to shaft misalignment. Therefore, there has been a demand for providing a new technology that can suppress shaft misalignment by simply and accurately aligning the rotation axis of the motor and the central axis of the transmissive optical element.

Means for Solving the Problems

[0006] To solve the above problems, a light source device according to one aspect of the present invention comprises a light source unit that emits light, and a light scanning unit that periodically scans the light emitted from the light source unit, wherein the light scanning unit rotates about a rotation axis extending in a direction intersecting the direction of incidence of the light, and has a transmission optical element having an incident surface into which the light incident from the light source unit is incident, and an emission surface that emits the light incident from the incident surface, and a drive unit that rotates the transmission optical element, wherein the drive unit has a rotation fixing unit that fixes the transmission optical element so as to be rotatable around the rotation axis, and a plurality of positioning pins arranged on the support surface of the transmission optical element in the rotation fixing unit and located on the same circle centered on the rotation axis, wherein the plurality of positioning pins are on the first side of the transmission optical element The optical element includes a first pin that abuts against the first side, a second pin that abuts against the second side surface of the optical element, and a third pin that abuts against the third side surface of the optical element. In a cross-section formed by a plane perpendicular to the axis of rotation, when the intersection of a first imaginary line perpendicular to the central axis and the first side surface of the optical element and the first side surface is defined as the first intersection, the intersection of a second imaginary line perpendicular to the central axis and the second side surface of the optical element and the second side surface is defined as the second intersection, and the intersection of a third imaginary line perpendicular to the central axis and the third side surface of the optical element and the third side surface is defined as the third intersection, the first position of the first intersection relative to the first pin, the second position of the second intersection relative to the second pin, and the third position of the third intersection relative to the third pin are each shifted to one side in the circumferential direction of the axis of rotation.

[0007] A method for manufacturing a light source device according to one aspect of the present invention is a method for manufacturing a light source device that scans light by causing light emitted from a light source unit to be incident on a transmissive optical element rotated by a drive unit, comprising the steps of: arranging a jig having a plurality of positioning pins located on the same circle centered on the rotation axis coaxially with the rotation axis of the drive unit; bringing the transmissive optical element placed on the jig into contact with the support surface of the drive unit; rotating the transmissive optical element or the jig in the circumferential direction of the rotation axis so that at least three of the plurality of positioning pins come into contact with the transmissive optical element; and fixing the transmissive optical element to the support surface while at least three of the plurality of positioning pins are in contact with the transmissive optical element.

[0008] A projector according to one aspect of the present invention comprises a light source device according to one aspect of the present invention, an optical modulation device that modulates light emitted from the optical scanning unit of the light source device according to image information, and a projection optical device that projects the image light emitted from the optical modulation device. [Brief explanation of the drawing]

[0009] [Figure 1] This is a plan view showing the schematic configuration of the projector according to the first embodiment. [Figure 2] This is a side view showing the schematic configuration of the projector. [Figure 3] This is a perspective view of the first light source unit and the first optical scanning unit. [Figure 4A] This is a schematic diagram illustrating the behavior of light when a transmissive optical element rotates. [Figure 4B] This is a schematic diagram showing a continuation of Figure 4A. [Figure 4C] This is a schematic diagram showing a continuation of Figure 4B. [Figure 4D] This is a schematic diagram showing a continuation of Figure 4C. [Figure 4E] This is a schematic diagram showing a continuation of Figure 4D. [Figure 4F] This is a schematic diagram showing a continuation of Figure 4E. [Figure 5] This is a perspective view showing the main components of the first optical scanning unit. [Figure 6] It is a cross-sectional view showing the main part configuration of the first light scanning unit. [Figure 7A] It is a diagram showing the assembly process of the first light scanning unit. [Figure 7B] It is a diagram of the assembly process showing the continuation of FIG. 7A. [Figure 8] It is a histogram showing the verification result of the assembly process of this embodiment. [Figure 9] It is a perspective view showing the main part configuration of the first light scanning unit of the second embodiment. [Figure 10] It is a configuration diagram in which the first transmissive optical element is rotated clockwise. [Figure 11] It is a diagram showing another layout of pins according to the cross-sectional shape of the transmissive optical element. [Figure 12] It is a diagram showing a configuration example when using positioning pins of different weights. [Figure 13] It is a diagram showing the assembly process in which positioning pins are provided on the jig side.

Mode for Carrying Out the Invention

[0010] [First Embodiment] Hereinafter, the first embodiment of the present invention will be described with reference to the drawings. The projector of this embodiment is an example of a liquid crystal projector using a liquid crystal panel as a light modulation device. In the following drawings, for the sake of easy viewing of each component, the scale of the dimensions may be made different depending on the component.

[0011] FIG. 1 is a plan view showing the schematic configuration of the projector 20 of this embodiment. FIG. 2 is a side view showing the schematic configuration of the projector 20. In FIG. 2, for the sake of easy viewing of the drawing, only the first light source unit and the first light scanning unit are shown for the optical system in the front stage of the light modulation device. FIG. 3 is a perspective view of the first light source unit and the first light scanning unit.

[0012] As shown in FIGS. 1 and 2, the projector 20 of the present embodiment includes a light source device 10, a first reflection mirror 41, a second reflection mirror 42, a green light modulation device 43G, an emission-side polarizing plate 44G, a blue light modulation device 43B, an emission-side polarizing plate 44B, a half-wave plate 46B, a red light modulation device 43R, an emission-side polarizing plate 44R, a half-wave plate 46R, an image light combining element 45, and a projection optical device 23. Although the projector 20 of the present embodiment includes half-wave plates 46B and 46R, it is not necessarily required to include them.

[0013] The light source device 10 of the present embodiment includes a first light source unit 11, a second light source unit 12, a third light source unit 13, a first light scanning unit 6, a second light scanning unit 7, a third light scanning unit 8, a first driving unit 35, a second driving unit 36, and a third driving unit 37. Each of the light scanning units 6, 7, and 8 includes a respective transmission optical element 15, 16, and 17.

[0014] Hereinafter, in the drawings, the XYZ orthogonal coordinate system will be used for explanation as necessary. The X-axis is an axis parallel to the optical axis AX2 of the second light source unit 12. The optical axis AX2 of the second light source unit 12 is defined as an axis along the principal ray of the green light LG emitted from the second light source unit 12. The Y-axis is an axis orthogonal to the X-axis and is an axis along the rotation axis of each of the transmission optical elements 15, 16, and 17. The Z-axis is an axis orthogonal to the X-axis and the Y-axis. The optical axis AX1 of the first light source unit 11 is defined as an axis along the principal ray of the blue light LB emitted from the first light source unit 11. The optical axis AX3 of the third light source unit 13 is defined as an axis along the principal ray of the red light LR emitted from the third light source unit 13. The Y-axis direction in the present embodiment corresponds to an example of the "direction intersecting the incident direction of light" of the present invention.

[0015] As shown in Figure 1, the first light source unit 11 emits blue light LB in the first wavelength band toward the first transmissive optical element 15. The second light source unit 12 emits green light LG in the second wavelength band toward the second transmissive optical element 16. The third light source unit 13 emits red light LR in the third wavelength band toward the third transmissive optical element 17. The first light source unit 11, the second light source unit 12, and the third light source unit 13 are arranged side by side in the Z-axis direction and emit light toward the same side (+X side). With this configuration, it is easy to standardize cooling members such as heat sinks for cooling the light source units 11, 12, and 13, and the light source device 10 can be miniaturized. Each of the light source units 11, 12, and 13 corresponds to an example of the "light source unit" of the present invention. In other words, the light source device 10 of this embodiment has three light source units.

[0016] Although the basic configurations of each light source unit 11, 12, and 13 are similar, Figures 2 and 3 show the detailed configuration of the first light source unit 11. Therefore, the specific configuration will be explained below using the first light source unit 11 as a representative example.

[0017] As shown in Figures 2 and 3, the first light source unit 11 comprises a plurality of first light-emitting elements 25 and a substrate 29. The first light-emitting elements 25 are composed of laser diodes that emit light in the first wavelength band. Therefore, the light emitted from the first light-emitting elements 25 is linearly polarized with coherence, has a narrow beam width, and is laser light with high parallelism. The first wavelength band is, for example, the blue wavelength band of 450 nm ± 5 nm. That is, the light emitted from the first light-emitting elements 25 is blue light. In this embodiment, laser diodes are given as the first light-emitting elements 25, but the invention is not limited to laser diodes. Light sources such as LEDs and lamps, along with optical systems for adjusting the polarization direction of light, optical systems for adjusting the beam width, color wheels, etc., can be used to generate light rays with a ratio of Lz / Ly of 1 / 2 or less, thereby replacing the laser diodes.

[0018] Multiple first light-emitting elements 25 are arranged in a row at predetermined intervals from each other along the Y-axis direction, that is, the direction perpendicular to the plane of the paper in Figure 1. In this embodiment, the first light source unit 11 is equipped with five first light-emitting elements 25, but the number of first light-emitting elements 25 is not particularly limited, and it is sufficient for multiple first light-emitting elements 25 to be arranged in a row along the Y-axis direction.

[0019] The substrate 29 supports a plurality of first light-emitting elements 25. Although not shown in the figures, a cooling member such as a heat sink for cooling the plurality of first light-emitting elements 25 may be provided on the side of the substrate 29 opposite to the side on which the plurality of first light-emitting elements 25 are provided.

[0020] As shown in Figure 1, the second light source unit 12 comprises a plurality of second light-emitting elements 26 and a substrate 29. The second light-emitting elements 26 are composed of laser diodes that emit light in the second wavelength band. Therefore, the light emitted from the second light-emitting elements 26 is linearly polarized with coherence, has a narrow beam width, and is highly parallel laser light. The second wavelength band is, for example, the green wavelength band of 530 nm ± 5 nm. That is, the light emitted from the second light-emitting elements 26 is green light.

[0021] Multiple second light-emitting elements 26 are arranged in a row along the Y-axis direction at predetermined intervals from one another. In this embodiment, the second light source unit 12 is equipped with five second light-emitting elements 26, but the number of second light-emitting elements 26 is not particularly limited, and it is sufficient for multiple second light-emitting elements 26 to be arranged in a row along the Y-axis direction.

[0022] The third light source unit 13 comprises a plurality of third light-emitting elements 27 and a substrate 29. Each third light-emitting element 27 is composed of a laser diode that emits light in the third wavelength band. Therefore, the light emitted from the third light-emitting elements 27 is linearly polarized with coherence, has a narrow beam width, and is highly parallel laser light. The third wavelength band is, for example, the red wavelength band of 650 nm ± 5 nm. In other words, the light emitted from the third light-emitting elements 27 is red light.

[0023] Multiple third light-emitting elements 27 are arranged in a row at predetermined intervals from each other along the Y-axis direction, that is, the direction perpendicular to the plane of the paper in Figure 1. The number of third light-emitting elements 27 is not particularly limited; it is sufficient that multiple third light-emitting elements 27 are arranged in a row along the Y-axis direction.

[0024] Although the basic configuration of each of the transmitted optical elements 15, 16, and 17 is similar, Figures 2 and 3 show the detailed configuration of the first optical scanning unit 6, so the specific configuration will be explained below using the first optical scanning unit 6 as an example. Each of the optical scanning units 6, 7, and 8 corresponds to an example of the "optical scanning unit" of the present invention. In other words, the light source device 10 of this embodiment is equipped with three optical scanning units.

[0025] As shown in Figures 1 to 3, the first optical scanning unit 6 is provided on the optical axis AX1. The first optical scanning unit 6 periodically scans the blue light LB emitted from the first light source unit 11. The first optical scanning unit 6 includes a first transmissive optical element (transmissive optical element) 15. The first transmissive optical element 15 is provided on the optical axis AX1. The first transmissive optical element 15 is composed of a translucent member that is rotatably supported. As the glass material of the translucent member constituting the first transmissive optical element 15, translucent materials such as optical glass such as BK7, quartz, or resin are used. The first transmissive optical element 15 is rotatable about a first rotation axis C1 that extends along the Y-axis direction intersecting the X-axis direction, which is the incident direction of the blue light LB. The first transmissive optical element 15 periodically scans the blue light LB incident from the first light source unit 11. The first rotation axis (rotation axis) C1 is connected to a first drive unit (drive unit) 35 consisting of a motor or the like. The first transmissive optical element 15 rotates about the first rotation axis C1 by the drive of the first drive unit 35.

[0026] As shown in Figure 3, the first transmissive optical element 15 has a first surface 15a and a second surface 15b that intersect the first rotation axis C1, and four side surfaces 15c that are perpendicular to the first surface 15a and the second surface 15b. In other words, the shape of the first transmissive optical element 15 is a regular quadrangular prism having six planes, including the first surface 15a, the second surface 15b, and the four side surfaces 15c. The cross-sectional shape of the first transmissive optical element 15, when cut by a plane perpendicular to the first rotation axis C1, is square. That is, the four sides 15c have the same area, and two opposing sides 15c are parallel to each other.

[0027] The first transmissive optical element 15 rotates about the first rotation axis C1 while transmitting blue light LB emitted from the first light source unit 11. In the first transmissive optical element 15, the side surface 15c into which the blue light LB emitted from the first light source unit 11 is incident is called the first incident surface. The side surface 15c from which the blue light LB incident from the first incident surface is emitted is called the first exit surface. The first incident surface and the first exit surface change over time and are one of two mutually parallel side surfaces 15c out of the four side surfaces 15c.

[0028] In this specification, when two sides of a transmissive optical element are said to be parallel to each other, "parallel" refers to a case where the angle between the two sides is in the range of 0 ± 5 degrees, taking into consideration the processing accuracy of the glass material constituting the light-transmitting member, the allowable range of parallelism of light, etc.

[0029] In this embodiment, the first transmissive optical element 15 has four first sides (sides) 15c, but the number of sides 15c does not necessarily have to be four; it is preferable that there be 2 × m (m: a natural number greater than or equal to 2). That is, it is preferable that the number of sides 15c be an even number, such as 6 or 8. If the number of sides 15c is even, each of all sides 15c is parallel to the side 15c opposite it, and there are no non-parallel sides 15c. As a result, the generation of stray light in the first transmissive optical element 15 is reduced, and the light utilization efficiency can be increased.

[0030] As shown in Figure 1, the second transmissive optical element (transmissive optical element) 16 is provided on the optical axis AX2. The second transmissive optical element 16 is composed of a translucent member that is rotatably supported. The second transmissive optical element 16 is rotatable about a second rotation axis (rotation axis) C2 that extends along the Y-axis direction. The second rotation axis C2 is connected to a second drive unit (drive unit) 36. The second transmissive optical element 16 rotates about the second rotation axis C2 by the drive of the second drive unit 36.

[0031] The second transmissive optical element 16 has a third surface 16a and a fourth surface 16b that intersect the second rotation axis C2, and four side surfaces 16c that are perpendicular to the third surface 16a and the fourth surface 16b. The second transmissive optical element 16 rotates about the second rotation axis C2 and transmits the green light LG emitted from the second light source unit 12. Therefore, the side surface 16c on which the green light LG emitted from the second light source unit 12 enters the second transmissive optical element 16 is not fixed, but changes over time. In the second transmissive optical element 16, the side surface 16c on which the green light LG emitted from the second light source unit 12 enters is called the second incident surface. The side surface 16c from which the green light LG entering from the second incident surface is emitted is called the second emission surface. In this case, the second incident surface and the second exit surface change over time and are either two of the four parallel side surfaces 16c.

[0032] In this embodiment, the second transmissive optical element 16 has four second sides (sides) 16c, but the number of sides 16c does not necessarily have to be four; it is preferable that there be 2 × n (n: a natural number greater than or equal to 2). That is, it is preferable that the number of sides 16c be an even number, such as 6 or 8. If the number of sides 16c is even, each of all sides 16c is parallel to the side 16c opposite it, and there are no sides 16c that do not have a parallel pair. As a result, the generation of stray light in the second transmissive optical element 16 is reduced, and the light utilization efficiency can be increased.

[0033] The third transmission optical element (transmission optical element) 17 is provided on the optical axis AX3. The third transmission optical element 17 is composed of a light-transmitting member that is rotatably supported. The third transmission optical element 17 is rotatable about a third rotation axis (rotation axis) C3 that extends along the Y-axis direction. The third rotation axis C3 is connected to a third drive unit 37. The third transmission optical element 17 rotates about the third rotation axis C3 by the drive of the third drive unit (drive unit) 37.

[0034] The third transmission optical element 17 has a fifth surface 17a and a sixth surface 17b that intersect the third rotation axis C3, and four side surfaces 17c that are perpendicular to the fifth surface 17a and the sixth surface 17b. The third transmission optical element 17 rotates about the third rotation axis C3 and transmits the red light LR emitted from the third light source unit 13. In the third transmission optical element 17, the side surface 17c into which the red light LR emitted from the third light source unit 13 is incident is called the third incident surface. The side surface 17c that emits the red light LR incident from the third incident surface is called the third exit surface. The third incident surface and the third exit surface change over time and are either two of the four side surfaces 17c that are parallel to each other.

[0035] In this embodiment, the third transmissive optical element 17 has four third sides (sides) 17c, but the number of sides 17c does not necessarily have to be four; it is preferable that there be 2 × p (p: a natural number greater than or equal to 2). That is, it is preferable that the number of sides 17c be an even number, such as 6 or 8. If the number of sides 17c is even, each of all sides 17c is parallel to the side 17c opposite it, and there are no non-parallel sides 17c. As a result, the generation of stray light in the third transmissive optical element 17 is reduced, and the light utilization efficiency can be increased.

[0036] The first transmissive optical element 15, the second transmissive optical element 16, and the third transmissive optical element 17 are made of different glass materials and have different refractive indices. Specifically, the refractive index of the first transmissive optical element 15 is smaller than that of the second transmissive optical element 16, and the refractive index of the second transmissive optical element 16 is smaller than that of the third transmissive optical element 17. That is, when the refractive index of the first transmissive optical element 15 is n1, the refractive index of the second transmissive optical element 16 is n2, and the refractive index of the third transmissive optical element 17 is n3, the relationship n1 < n2 < n3 is satisfied.

[0037] Alternatively, the first transmissive optical element 15, the second transmissive optical element 16, and the third transmissive optical element 17 may be made of quartz. In each of the transmissive optical elements 15, 16, 17, as the amount of light transmitted through the light-transmitting member increases, the amount of light absorbed by the light-transmitting member also increases, and thermal distortion may occur in the light-transmitting member. In this case, the polarization directions of the respective color lights LB, LG, LR emitted from the respective light source units 11, 12, 13 are disturbed, and the linearly polarized light incident on the light-transmitting member becomes elliptically polarized light and is emitted from the light-transmitting member. As a result, when laser diodes are used for the respective light-emitting elements 25, 26, 27 in the projector 20, the effect that a predetermined contrast can be obtained without providing an incident-side polarizing plate is lost. That is, even though laser diodes are used for the respective light-emitting elements 25, 26, 27, it becomes necessary to use an incident-side polarizing plate for aligning the polarization directions. Therefore, in order to obtain the above effect, it is desirable to use a glass material with low thermal distortion, specifically, a glass material with a small Young's modulus and a small coefficient of thermal expansion. As an example, it is desirable to use quartz.

[0038] Hereinafter, the behavior when the respective color lights LB, LG, LR pass through the respective transmissive optical elements 15, 16, 17 will be described. Since the behaviors of the respective color lights LB, LG, LR are common to each other, here, the description will be given by taking the blue light LB emitted from the first light source unit 11 as a representative.

[0039] Figures 4A to 4F are schematic diagrams illustrating the behavior of blue light LB as the first transmissive optical element 15 rotates. In this example, viewed from the +Y side, the first transmissive optical element 15 rotates clockwise around the first rotation axis C1, and the diagrams show the progression of time from Figure 4A to Figure 4F.

[0040] In Figures 4A to 4F, the rotation angle ω of the first transmitting optical element 15 is defined as the angle between the optical axis AX1 and the straight line M that passes through the first rotation axis C1 and is perpendicular to the first side surface 15c1 of the four side surfaces 15c of the first transmitting optical element 15. In reality, the blue light LB has a predetermined luminous flux width in the Z-axis direction, but here we will focus on the behavior of the light ray LB0 traveling along the optical axis AX1.

[0041] Figure 4A shows the initial state of the first transmission optical element 15. That is, the first transmission optical element 15 is not rotating, the straight line M and the optical axis AX1 coincide, and the rotation angle ω is 0 degrees. In this case, the light ray LB0 is incident perpendicular to the first side surface 15c1, and therefore travels through the inside of the first transmission optical element 15 along the optical axis AX1 without being refracted by the first side surface 15c1. Next, the light ray LB0 is also incident perpendicular to the second side surface 15c2, which is parallel to the first side surface 15c1. Therefore, the light ray LB0 is emitted from the first transmission optical element 15 without being refracted by the second side surface 15c2 and travels along the optical axis AX1.

[0042] Next, as shown in Figure 4B, when the first transmissive optical element 15 rotates by a rotation angle ω, the light ray LB0 is incident on the first side surface 15c1 at an incident angle equal to the rotation angle ω. Therefore, the light ray LB0 is refracted in the direction shown in the figure (+Z side) and travels inside the first transmissive optical element 15. Next, the light ray LB0 is also incident on the second side surface 15c2 at a predetermined incident angle, so it is refracted on the second side surface 15c2 and emitted from the first transmissive optical element 15. At this time, since the first side surface 15c1 and the second side surface 15c2 are parallel to each other, the incident angle of the light ray LB0 on ​​the first side surface 15c1 is equal to the incident angle of the light ray LB0 on ​​the second side surface 15c2, and the refraction angle of the light ray LB0 incident on the first side surface 15c1 and the refraction angle of the light ray LB0 emitted from the second side surface 15c2 have opposite signs but equal absolute values. As a result, the refraction angle of the ray LB0 upon incidence onto the first side surface 15c1 and the refraction angle upon emission from the second side surface 15c2 cancel each other out. Consequently, the ray LB0 travels parallel to the optical axis AX1 at a position displaced by a displacement amount d to the +Z side from the optical axis AX1.

[0043] Next, as shown in Figure 4C, when the rotation angle ω of the first transmissive optical element 15 becomes larger than that in Figure 4B, the incident angle of the light ray LB0 increases, and the refraction angle increases. Therefore, the displacement d of the light ray LB0 from the optical axis AX1 becomes larger than in Figure 4B. Also, the state in which the light ray LB0 travels parallel to the optical axis AX1 is always maintained. Between rotation angles ω of 0 and 45 degrees, the displacement d increases monotonically with increasing rotation angle ω.

[0044] Next, as shown in Figure 4D, when the rotation angle ω of the first transmitting optical element 15 exceeds 45 degrees, the incident surface of the light ray LB0 changes from the first side surface 15c1 to the third side surface 15c3. At this time, the light ray LB0 is refracted at the third side surface 15c3, but the direction of refraction changes from that of the period up to Figure 4C, and it is refracted in the direction shown in the figure (towards -Z). The exit surface of the light ray LB0 also changes from the second side surface 15c2 to the fourth side surface 15c4, but since the third side surface 15c3 and the fourth side surface 15c4 are parallel to each other, the relationship in which the refraction angle when the light ray LB0 is incident on the third side surface 15c3 and the refraction angle when it is exited from the fourth side surface 15c4 cancel each other out remains the same as in the period up to Figure 4C. As a result, the light ray LB0 travels parallel to the optical axis AX1 at a position displaced by a displacement amount d from the optical axis AX1 to the -Z side.

[0045] Next, as shown in Figure 4E, when the rotation angle ω of the first transmissive optical element 15 becomes larger than that in Figure 4D, the incident angle of the light ray LB0 decreases, and the refraction angle decreases. Therefore, the displacement d of the light ray LB0 from the optical axis AX1 becomes smaller than in Figure 4D. Thus, between rotation angles ω of 45 degrees and 90 degrees, the displacement d decreases monotonically with increasing rotation angle ω.

[0046] Next, as shown in Figure 4F, when the rotation angle ω of the first transmissive optical element 15 becomes 90 degrees, the incident surface changes from the initial side surface 15c1 to the side surface 15c2, but the behavior of the light ray LB0 becomes the same as the initial state shown in Figure 4A.

[0047] Thus, if the first incident surface and the first exit surface of the first transmitting optical element 15 are parallel to each other, the direction of propagation of the light ray LB0 does not change regardless of the rotation angle ω of the first transmitting optical element 15, and the light ray LB0 moves in a direction parallel to the optical axis AX1 over time. When the rotation angle ω is 0 degrees, the displacement amount d of the light ray LB0 is 0, and between rotation angles ω from 0 to 45 degrees, the displacement amount d increases to either the +Z side or the -Z side. The moment the rotation angle ω exceeds 45 degrees, the absolute value of the displacement amount d remains the same, but the direction of displacement reverses, and between rotation angles ω from 45 to 90 degrees, the displacement amount d decreases, and when the rotation angle ω reaches 90 degrees, the displacement amount d becomes 0. After 90 degrees, the above behavior is repeated. Therefore, when the first transmitting optical element 15 rotates once, the displacement amount d of the light ray LB0 repeats the above cycle for 4 periods. The displacement of the light ray LB0 can be appropriately set by adjusting parameters such as the refractive index and size of the first transmitting optical element 15.

[0048] The above explanation focused only on the light ray LB0 traveling along the optical axis AX1. However, in reality, as shown in Figure 3, the blue light LB extends linearly in the Y-axis direction, which is perpendicular to the Z-axis direction in which the blue light LB is displaced. Therefore, after being reflected by the first reflection mirror 41 (described later), the blue light LB is scanned within the two-dimensional illuminated region Q on the illuminated surface (light modulator 43B). Similarly, the green light LG is scanned within the two-dimensional illuminated region Q on the illuminated surface (light modulator 43G). The red light LR, like the blue light LB, is reflected by the second reflection mirror 42 (described later) and then scanned within the two-dimensional illuminated region Q on the illuminated surface (light modulator 43R). In this way, each of the transmitted optical elements 15, 16, and 17 scans the blue light LB, green light LG, and red light LR in a direction perpendicular to the Y-axis direction as it rotates around each of the rotation axes C1, C2, and C3, thereby scanning within the two-dimensional illuminated area Q on the illuminated surface.

[0049] As shown in Figure 1, the first reflective mirror 41 reflects the blue light LB emitted from the first transmitting optical element 15 toward the blue light modulation device 43B. In this way, the first reflective mirror 41 bends the optical path of the blue light LB emitted from the first transmitting optical element 15 from the +X direction to the -Z direction.

[0050] The second reflective mirror 42 reflects the red light LR emitted from the third transmissive optical element 17 toward the red light modulation device 43R. In this way, the second reflective mirror 42 bends the optical path of the red light LR emitted from the third transmissive optical element 17 from the +X direction to the +Z direction.

[0051] The blue light modulator 43B modulates the blue light LB emitted from the first transmissive optical element 15 of the light source device 10 according to image information to form blue image light. The green light modulator 43G modulates the green light LG emitted from the second transmissive optical element 16 of the light source device 10 according to image information to form green image light. The red light modulator 43R modulates the red light LR emitted from the third transmissive optical element 17 of the light source device 10 according to image information to form red image light. A transmissive liquid crystal panel is used in each of the light modulators 43G, 43B, and 43R. The driving method for the liquid crystal panel is not particularly limited and may include twisted nematic (TN) method, vertical alignment (VA) method, transverse field (IPS) method, etc.

[0052] As shown in Figure 1, each optical modulator 43G, 43B, and 43R is equipped with an output polarizer 44G, 44B, and 44R on its optical output side. The output polarizers 44G, 44B, and 44R transmit linearly polarized light in a specific direction.

[0053] The image photosynthesis element 45 receives image light of each color emitted from the green light modulator 43G, the blue light modulator 43B, and the red light modulator 43R, synthesizes image light corresponding to red light LR, green light LG, and blue light LB, and emits the synthesized image light toward the projection optical device 23. For example, a cross dichroic prism is used for the image photosynthesis element 45.

[0054] Half-wave plates 46B and 46R are provided between the blue light modulator 43B and the image photosynthesis element 45, and between the red light modulator 43R and the image photosynthesis element 45, respectively. The half-wave plates 46B and 46R impart a half-wave phase difference to the incident color light, rotating the polarization direction of linearly polarized light by 90 degrees. This makes it possible to make the polarization direction of the green light LG incident on the image photosynthesis element 45 different from the polarization direction of the blue light LB and red light LR incident on the image photosynthesis element 45. This configuration makes it possible to increase the efficiency of the image photosynthesis element 45.

[0055] The projection optical device 23 is composed of multiple projection lenses. The projection optical device 23 magnifies and projects the image light emitted from the image photosynthesis element 45 toward a projection surface such as a screen. As a result, an image is displayed on the projection surface.

[0056] By the way, in the light source device 10 of this embodiment, as described above, a configuration is adopted in which the transmitted optical elements 15, 16, and 17 in each optical scanning unit 6, 7, and 8 are rotated by the drive units 35, 36, and 37. However, if the misalignment between the central axis of each transmitted optical element 15, 16, and 17 and the rotation axis of each drive unit 35, 36, and 37 becomes large, there is a risk of noise and vibration due to axial wobble.

[0057] In contrast, the projector 20 of this embodiment has a configuration that allows for simple and highly accurate positioning of the axes of the transmissive optical elements 15, 16, 17 and the drive units 35, 36, 37 in each of the optical scanning units 6, 7, and 8. The positioning structure of the transmissive optical elements 15, 16, 17 and the drive units 35, 36, 37 will be described below. Since the positioning structure of each of the optical scanning units 6, 7, and 8 is common, the positioning configuration of the first optical scanning unit 6 will be used as an example for explanation.

[0058] Figure 5 is a perspective view showing the main components of the first optical scanning unit 6. The first drive unit 35 of the first optical scanning unit 6 shown in Figure 5 has a main body 50 consisting of a motor, a rotation fixing unit 51, and a plurality of positioning pins P. The rotation fixing unit 51 fixes the first transmission optical element 15 so that it can rotate around the first rotation axis C1. The rotation fixing unit 51 has a support surface 51a that supports the second surface 15b of the first transmission optical element 15. The second surface 15b of the first transmission optical element 15 is fixed to the support surface 51a, for example, via adhesive.

[0059] Multiple positioning pins P are arranged on the support surface 51a of the rotation fixing part 51 and are located on the same circle centered on the first rotation axis C1. Specifically, the multiple positioning pins P are located on a single circle KC shown by the dashed line.

[0060] In this specification, the statement that multiple positioning pins P are located on the same circle centered on the first rotation axis C1 does not mean that the center of each positioning pin P is located on a single circle, but rather that the same circle overlaps with any part of the positioning pins P having a predetermined planar area. In other words, in this embodiment, at least one center of the multiple positioning pins P may be located on the same circle, or it may be located slightly offset from the same circle.

[0061] The multiple positioning pins P are pins that position the first transmission optical element 15 relative to the rotation fixing part 51 of the first drive unit 35 so that the first rotation axis C1 of the first drive unit 35 coincides with the central axis 150 of the first transmission optical element 15. In this embodiment, the multiple positioning pins P include four pins. The central axis 150 of the first transmission optical element 15 coincides with the center of gravity of the first transmission optical element 15.

[0062] Specifically, the multiple positioning pins P include a first pin P1, a second pin P2, a third pin P3, and a fourth pin P4. The first pin P1 contacts the first side surface 15c1 of the four side surfaces 15c of the first transmissive optical element 15. The second pin P2 contacts the second side surface 15c2 of the four side surfaces 15c of the first transmissive optical element 15. The third pin P3 contacts the third side surface 15c3 of the four side surfaces 15c of the first transmissive optical element 15. The fourth pin P4 faces the fourth side surface 15c4 of the first transmissive optical element 15 with a small gap between them. In other words, the fourth pin P4 does not contact the fourth side surface 15c4 of the first transmissive optical element 15. Thus, in the first optical scanning unit 6, three of the multiple positioning pins P are in contact with the side surface 15c of the first transmissive optical element 15.

[0063] In this embodiment, by using four pins P1 to P4 as multiple positioning pins P, the alignment of the combined center of gravity of each pin with the first rotation axis C1 of the first drive unit 35 becomes easier compared to the case where three pins are used, thereby improving the ease of assembly of the first optical scanning unit 6.

[0064] Figure 6 is a cross-sectional view showing the main components of the first optical scanning unit 6 by a plane perpendicular to the first rotation axis C1. More specifically, Figure 6 is a cross-sectional view passing through the contact portion with the positioning pin P in the first transmissive optical element 15. In Figure 6, the imaginary line perpendicular to the central axis 150 and the first side surface 15c1 of the first transmissive optical element 15 is called the first imaginary line K1, the imaginary line perpendicular to the central axis 150 and the second side surface 15c2 is called the second imaginary line K2, and the imaginary line perpendicular to the central axis 150 and the third side surface 15c3 is called the third imaginary line K3. The intersection of the first imaginary line K1 and the first side surface 15c1 is called the first intersection point 151, the intersection of the second imaginary line K2 and the second side surface 15c2 is called the second intersection point 152, and the intersection of the third imaginary line K3 and the third side surface 15c3 is called the third intersection point 153.

[0065] At this time, as shown in Figure 6, the first position T1 of the first intersection 151 relative to the first pin P1, the second position T2 of the second intersection 152 relative to the second pin P2, and the third position T3 of the third intersection 153 relative to the third pin P3 are each shifted to one side (counterclockwise in Figure 6) in the circumferential direction of the first rotation axis C1.

[0066] As shown in Figure 6, in the first optical scanning unit 6 of this embodiment, the first transmission optical element 15 is rotated clockwise R1 around the first rotation axis C1. In other words, the first position T1, the second position T2, and the third position T3 are shifted in the opposite direction (counterclockwise) to the clockwise rotation R1 of the first transmission optical element 15.

[0067] With this configuration, when the rotating fixing part 51 rotates clockwise R1, acceleration is generated in each pin P1 to P3 that contacts each side surface 15c1, 15c2, 15c3 of the first transmissive optical element 15. As a result, each pin P1 to P3 becomes more closely attached to each side surface 15c1, 15c2, 15c3, and the first transmissive optical element 15 is held more stably with respect to the rotating fixing part 51. Therefore, the detachment of the first transmissive optical element 15 from the rotating fixing part 51 can be suppressed.

[0068] As shown in Figure 6, each pin P1 to P4 is cylindrical. With this configuration, the contact area between the first pin P1, second pin P2, and third pin P3 and each side surface 15c1, 15c2, and 15c3 is linear, so the contact area between each pin P1 to P3 and the first transmissive optical element 15 can be minimized. Therefore, the positioning accuracy of the first transmissive optical element 15 by each pin P1 to P3 can be improved.

[0069] Next, we will explain the assembly process of the first optical scanning unit 6, which is part of the manufacturing process of the light source device 10. Figures 7A and 7B show the assembly process of the first optical scanning unit 6. First, as shown in Figure 7A, the second surface 15b of the first transmissive optical element 15 is positioned inside the region surrounded by a plurality of positioning pins P arranged on the support surface 51a. At this time, the first transmissive optical element 15 is positioned so that each side surface 15c1, 15c2, 15c3, 15c4 and each pin P1 to P4 face each other.

[0070] Each pin P1 to P4 is provided on the support surface 51a of the rotation fixing part 51 such that the first rotation axis C1 passes through the intersection of the line connecting the centers of the first pin P1 and the second pin P2 and the line connecting the centers of the third pin P3 and the fourth pin P4. In this embodiment, each pin P1 to P4 is composed of pins with the same outer diameter and the same weight, and the combined center of gravity of each pin P1 to P4 is set on the first rotation axis C1.

[0071] To facilitate assembly, the dimension S1 between the first pin P1 and the second pin P2 is set to be slightly larger than the dimension S2 between the first side surface 15c1 and the second side surface 15c2 of the first transmissive optical element 15, and the dimension S3 between the third pin P3 and the fourth pin P4 is set to be slightly larger than the dimension S4 between the third side surface 15c3 and the fourth side surface 15c4 of the first transmissive optical element 15. In other words, when the first transmissive optical element 15 is placed in a region surrounded by multiple positioning pins P, a gap will be created between the side surface 15c of the first transmissive optical element 15 and each positioning pin P. Therefore, after positioning the first transmissive optical element 15 in the region surrounded by multiple positioning pins P, if the first transmissive optical element 15 is positioned to one side, for example as shown in Figure 7A, such that the second side surface 15c2 and the third side surface 15c3 abut against the second pin P2 and the third pin P3 respectively, a misalignment occurs between the first rotation axis C1 and the central axis 150 of the first transmissive optical element 15 by the intersection of the above dimensions S1 and S3 of the pins. As described above, if an axial misalignment occurs between the first rotation axis C1 and the central axis 150 of the first transmission optical element 15, noise and vibration due to axial wobble may occur. Therefore, it is desirable to minimize the axial misalignment between the first rotation axis C1 and the central axis 150 as much as possible.

[0072] In contrast, in the assembly process of this embodiment, the first transmissive optical element 15 is rotated in the circumferential direction of the first rotation axis C1 from the state shown in Figure 7A. Specifically, as shown in Figure 7B, the first transmissive optical element 15 is rotated counterclockwise R2 around the axis of the first rotation axis C1, so that at least three of the multiple pins P come into contact with the side surface 15c of the first transmissive optical element 15. In this embodiment, as described above, each pin P1 to P3 comes into contact with each side surface 15c1, 15c2, and 15c3.

[0073] Finally, with each pin P1 to P3 in contact with the respective side surfaces 15c1, 15c2, and 15c3, the second surface 15b of the first transmissive optical element 15 is fixed to the support surface 51a. In this way, the first optical scanning unit 6 of this embodiment can be assembled.

[0074] The inventors focused on the fact that by rotating the first transmissive optical element 15, which is positioned in a region surrounded by a plurality of positioning pins P as described above, around the first rotation axis C1, and bringing at least three pins P into contact with the side surface 15c of the first transmissive optical element 15, the axial misalignment between the first rotation axis C1 and the central axis 150 of the first transmissive optical element 15 is reduced, and verified the effect through simulation.

[0075] Figure 8 is a histogram showing the results of a simulation verifying the effect of using the assembly process of this embodiment. The solid line in Figure 8 is the histogram corresponding to the assembly process in which the transmitted optical element is rotated to contact at least three pins, and the dashed line in Figure 8 is the histogram corresponding to the assembly process of a comparative example in which the transmitted optical element is aligned to two pins without rotation. Each of the solid and dashed histograms was calculated 30,000 times under the condition that the positions of the four pins were randomly varied by the same amount. In Figure 8, the horizontal axis shows the axial misalignment (unit: mm), and the vertical axis shows the frequency corresponding to each axial misalignment.

[0076] As shown in Figure 8, the histogram shown by the solid line shows an increase in the frequency of small axis misalignment compared to the histogram shown by the dashed line, meaning that the axis misalignment is smaller. In other words, the assembly process of this embodiment results in smaller axis misalignment than the one-sided assembly process of the comparative example. Therefore, with the first optical scanning unit 6 assembled in the assembly process of this embodiment, by fixing the second surface 15b of the first transmissive optical element 15 to the support surface 51a while each pin P1 to P3 is in contact with each side surface 15c1, 15c2, 15c3, the first rotation axis C1 and the central axis 150 of the first transmissive optical element 15 can be easily and accurately aligned, thereby suppressing the occurrence of axial runout.

[0077] Furthermore, the second optical scanning unit 7 and the third optical scanning unit 8 have the same configuration as the first optical scanning unit 6. In other words, as shown in Figure 1, the second optical scanning unit 7 fixes the second transmission optical element 16 to the second drive unit 36 ​​with at least three pins P in contact with the side surface 16c, so that the second rotation axis C2 and the central axis of the second transmission optical element 16 can be easily and accurately aligned, thereby suppressing the occurrence of axial runout. Furthermore, since the third optical scanning unit 8 fixes the third transmission optical element 17 to the third drive unit 37 with at least three pins P in contact with the side surface 17c, the third rotation axis C3 and the central axis of the third transmission optical element 17 can be easily and accurately aligned, thereby suppressing the occurrence of axial wobble.

[0078] As described above, the light source device 10 of this embodiment includes a first light source unit 11 that emits blue light LB, The system includes a first optical scanning unit 6 that periodically scans the blue light LB emitted from a first light source unit 11. The first optical scanning unit 6 rotates about a first rotation axis C1 that extends along a direction intersecting the incident direction of the blue light LB, and includes a first transmissive optical element 15 having an incident surface into which the blue light LB incident from the first light source unit 11 is incident, and an exit surface that emits the blue light LB incident from the incident surface, and a first drive unit 35 that rotates the first transmissive optical element 15. The first drive unit 35 includes a rotation fixing unit 51 that fixes the first transmissive optical element 15 so that it can rotate around a first rotation axis C1, and a plurality of positioning pins P1 arranged on the support surface 51a of the first transmissive optical element 15 in the rotation fixing unit 51 and located on the same circle centered on the first rotation axis C1. The plurality of positioning pins P include a first pin P1 that abuts against the first side surface 15c1 of the first transmissive optical element 15, a second pin P2 that abuts against the second side surface 15c2 of the first transmissive optical element 15, and a third pin P3 that abuts against the third side surface 15c3 of the first transmissive optical element 15. On a cross-section formed by a plane perpendicular to the first rotation axis C1, the intersection point of the first imaginary line K1 perpendicular to the central axis 150 and the first side surface 15c1 of the first transmissive optical element 15 is defined as the first intersection point 151, the intersection point of the second imaginary line K2 perpendicular to the central axis 150 and the second side surface 15c2 of the first transmissive optical element 15 is defined as the second intersection point 152, and the intersection point of the third imaginary line K3 perpendicular to the central axis 150 and the third side surface 15c3 of the first transmissive optical element 15 is defined as the third intersection point 153. Then, the first position T1 of the first intersection point 151 with respect to the first pin P1, the second position T2 of the second intersection point 152 with respect to the second pin P2, and the third position T3 of the third intersection point 153 with respect to the third pin P3 are each shifted to one side in the circumferential direction of the first rotation axis C1.

[0079] According to the light source device 10 of this embodiment, the first transmitted optical element 15 can be fixed to the support surface 51a of the rotation fixing part 51 with each pin P1 to P3 in contact with the respective sides 15c1, 15c2, and 15c3 of the first transmitted optical element 15 by twisting the first transmitted optical element 15 around the first rotation axis C1. Therefore, compared to the case where the two positioning pins P are offset to one side, the first rotation axis C1 and the central axis 150 of the first transmitted optical element 15 can be aligned simply and with high precision, thereby suppressing the occurrence of axial runout.

[0080] Therefore, according to the light source device 10 of this embodiment, it is possible to suppress the generation of noise and vibration due to axial runout between the central axis 150 of the first transmitted optical element 15 and the first rotation axis C1 of the first drive unit 35. Furthermore, according to the light source device 10 of this embodiment, it is also possible to suppress the generation of noise and vibration due to axial runout between the central axes of each transmitted optical element 16, 17 and the rotation axes of each drive unit 36, 37.

[0081] Furthermore, in the light source device 10 of this embodiment, the first position T1, the second position T2, and the third position T3 are shifted in the opposite direction to the rotation direction of the first transmitted optical element 15. As a result, the acceleration generated in each pin P1 to P3 when the rotating fixing part 51 rotates causes each pin P1 to P3 to be in close contact with each side surface 15c1, 15c2, and 15c3. Therefore, the first transmissive optical element 15 is stably held by the rotating fixing part 51, and the occurrence of detachment can be suppressed.

[0082] Furthermore, in the light source device 10 of this embodiment, by using four pins P1 to P4 as multiple positioning pins P, it becomes easy to align the combined center of gravity of each pin P1 to P4 with the first rotation axis C1 of the first drive unit 35. Therefore, the ease of assembly of the first optical scanning unit 6 can be improved.

[0083] Furthermore, in the light source device 10 of this embodiment, by making each pin P1 to P4 cylindrical, the contact area between each pin P1 to P3 and the first transmissive optical element 15 can be minimized. This improves the positioning accuracy of the first transmissive optical element 15 by each pin P1 to P3.

[0084] The projector 20 of this embodiment includes a light source device 10, a blue light modulation device 43B, a green light modulation device 43G, and a red light modulation device 43R that modulate the light emitted from each of the optical scanning units 6, 7, and 8 of the light source device 10 according to image information, and a projection optical device 23 that projects the light modulated by each of the optical modulation devices 43B, 43G, and 43R. According to the projector 20 of this embodiment, since it is equipped with a light source device 10 that also suppresses the generation of noise and vibration due to axial wobble, a projector with excellent quietness can be realized.

[0085] In this embodiment, the first pin P1, the second pin P2, and the third pin P3 of the multiple positioning pins P are shown as contacting the side surface 15c of the first transmissive optical element 15. However, depending on the outer diameter of the pins P, the fourth pin P4 may also contact the fourth side surface 15c4 of the first transmissive optical element 15. In other words, in the present invention, the above-mentioned effects can be achieved if at least three of the multiple positioning pins are in contact with the side surface of the transmissive optical element.

[0086] [Second Embodiment] Next, a projector according to the second embodiment of the present invention will be described. The basic configuration of the projector in this embodiment is the same as in the first embodiment, but the configuration of each optical scanning unit of the light source device differs from that of the first embodiment. Therefore, in the following description, the first optical scanning unit will be used as an example, and the configurations of the second and third optical scanning units will not be described.

[0087] Figure 9 is a perspective view showing the main components of the first optical scanning unit of this embodiment. In Figure 9, components common to the drawings of the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. As shown in Figure 9, in the light source device 100 of this embodiment, the first light source unit 21 is equipped with one light-emitting element 21a. Therefore, the blue light LB emitted from the first light source unit 21 is composed of a single ray.

[0088] The first optical scanning unit 106 of this embodiment includes a first transmission optical element 15, a first drive unit 35, a downstream transmission optical element 55 positioned behind the first transmission optical element 15, and a rotary drive device 95 for driving the downstream transmission optical element 55.

[0089] The downstream transmission optical element 55 has the same configuration as the first transmission optical element 15, but is installed in a position where the first transmission optical element 15 is rotated 90 degrees around the X-axis. The rotation drive device 95 is a motor that rotates the downstream transmission optical element 55 around a fourth rotation axis C4 that extends along the Z-axis direction.

[0090] In this embodiment, since the blue light LB passes through the two transmissive optical elements 15 and 55, the blue light LB is displaced in two mutually orthogonal directions over time. Specifically, as shown in Figure 9, the blue light LB emitted from the first light source unit 21 is scanned in the Z-axis direction by the first transmissive optical element 15 and in the Y-axis direction, which is orthogonal to the Z-axis direction, by the subsequent transmissive optical element 55. That is, the blue light LB emitted from the first light source unit 21 is scanned by the first transmissive optical element 15 and the subsequent transmissive optical element 55 within a two-dimensional illuminated area Q (blue light optical modulator 43B) on the illuminated surface.

[0091] [Effects of the second embodiment] According to the light source device 100 of this embodiment, even when using a first optical scanning unit 106 that scans a single blue light beam LB emitted from the first light source unit 21 in two directions, the first rotation axis C1 and the central axis 150 of the first transmission optical element 15 can be easily and accurately aligned to suppress the occurrence of axial wobble. Furthermore, the rotational drive device 95 for rotating the downstream transmissive optical element 55 may be configured in the same way as the first drive unit 35 of the first transmissive optical element 15. With this configuration, the fourth rotation axis C4 and the central axis of the downstream transmissive optical element 55 can be easily and accurately aligned, thereby suppressing the occurrence of axial runout.

[0092] (First variation) In the assembly process of the above embodiment, as shown in Figure 7B, the first transmissive optical element 15 is rotated counterclockwise around the axis of the first rotation axis C1 as an example, but the first transmissive optical element 15 may also be rotated clockwise with respect to the first rotation axis C1.

[0093] Figure 10 shows the configuration when the first transmissive optical element 15 is rotated clockwise with respect to the first rotation axis C1. For simplicity of explanation, even in the case shown in Figure 10, each pin P1 to P3 is assumed to be in contact with the side surface 15c of the first transmissive optical element 15.

[0094] As shown in Figure 10, the first position T1 of the first intersection 151 relative to the first pin P1, the second position T2 of the second intersection 152 relative to the second pin P2, and the third position T3 of the third intersection 153 relative to the third pin P3 are each shifted to one side (clockwise) in the circumferential direction of the first rotation axis C1. In other words, the first position T1, the second position T2, and the third position T3 are each shifted to the same side (clockwise) as the clockwise rotation direction R1 of the first transmitted optical element 15. With this configuration, when the rotating fixing part 51 rotates clockwise R1, acceleration is generated in the direction that separates each side surface 15c1, 15c2, and 15c3 of the first transmissive optical element 15 from each pin P1 to P3. Therefore, the acceleration due to the rotation of each pin P1 to P3 no longer acts on each side surface 15c1, 15c2, and 15c3, so it is possible to suppress the occurrence of defects such as chipping or cracking of the side surface 15c of the first transmissive optical element 15 due to stress from each pin P1 to P3.

[0095] (Second variation) In the above explanation, an example was given of using four positioning pins P for a first transmissive optical element 15 whose cross-sectional shape is square due to a plane perpendicular to the first rotation axis C1. However, it is preferable to vary the number of positioning pins according to the cross-sectional shape of the transmissive optical element.

[0096] For example, if the cross-sectional shape of the transmissive optical element is a regular 2N polygon (where N is an integer) and the weight of each positioning pin is the same, the positioning pins should be arranged so that the number of pins is 3 or more, a divisor of 2N, and forms a polygon. Figure 11 shows examples of the number and arrangement of positioning pins according to the cross-sectional shape of the transmissive optical element. As shown in Figure 11, when using a transmissive optical element 5A with a regular hexagonal cross-section, three positioning pins P should be arranged in a triangular shape. When using a transmissive optical element 5B with a regular octagonal cross-section, four positioning pins P should be arranged in a square shape. When using a transmissive optical element 5C with a regular decagonal cross-section, five positioning pins P should be arranged in a pentagonal shape. When using a transmissive optical element 5D with a regular dodecagonal cross-section, four positioning pins P should be arranged in a square shape. When using a transmissive optical element 5E with a regular quadrilateral cross-section, seven positioning pins P should be arranged in a heptagonal shape. Although not shown in the diagram, if the cross-sectional shape is a regular dodecagon, three positioning pins may be arranged in a triangular shape, or six positioning pins may be arranged in a hexagonal shape.

[0097] (Third variation) In the above embodiment, we took the example of a case where the weights of the multiple positioning pins are all the same, but the weights of at least one of the positioning pins may be different. In such a case where the weights of the positioning pins are different, the arrangement and weights of the multiple positioning pins should be designed so that the combined center of gravity of the multiple positioning pins coincides with the center of gravity (rotation axis) of the transmitted optical element.

[0098] Furthermore, if the weights of the positioning pins are not the same, it is not necessary to satisfy the above-mentioned pin arrangement conditions (3 or more pins, a divisor of 2N, and arranged in a gonal shape). For example, if the cross-sectional shape of the transmitted optical element is a regular decagon, three positioning pins of different weights can be used, as described later.

[0099] Figure 12 shows variations in configurations when a regular decagonal transmissive optical element is used with three positioning pins of different weights. As shown on the left side of Figure 12, the decagonal transmissive optical element 5F may be held by three positioning pins P10 arranged in an isosceles triangle with an acute vertex angle. In this case, the weight of the positioning pins P10 at the vertex of the isosceles triangle becomes heavier than the weight of the positioning pins P10 at both ends of the base, and the center of gravity of each positioning pin P10 coincides with the center of gravity of the transmissive optical element.

[0100] Alternatively, as shown in the center of Figure 12, the decagonal transmissive optical element 5F may be held by three positioning pins P11 arranged in an isosceles triangle with an obtuse vertex angle. In this case, the weight of the positioning pins P11 at the vertex of the isosceles triangle becomes heavier than the weight of the positioning pins P11 at both ends of the base of the isosceles triangle, and the center of gravity of each positioning pin P11 coincides with the center of gravity of the transmissive optical element.

[0101] Alternatively, as shown on the right side of Figure 12, the decagonal transmissive optical element 5F may be held by three positioning pins P12 arranged in an isosceles triangle with an obtuse vertex angle. In this case, the weight of the positioning pins P12 at the vertex of the isosceles triangle becomes heavier than the weight of the positioning pins P12 at both ends of the base of the isosceles triangle, resulting in a state where the center of gravity of each positioning pin P12 does not coincide with the center of gravity of the transmissive optical element.

[0102] Thus, according to the present invention, even if the center of gravity of the positioning pin P12 and the transmissive optical element 5F do not coincide, the axial misalignment between the rotation axis and the center of gravity (center) of the transmissive optical element 5 can be reduced by bringing the transmissive optical element 5F into contact with the three positioning pins.

[0103] Therefore, according to the present invention, even when the positioning pins are positioned so as not to coincide with the center of gravity of the transmitted optical element, the occurrence of axial misalignment can be suppressed. This configuration allows for greater freedom in the layout of the positioning pins.

[0104] The technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, in each of the optical scanning units of the above embodiment, the positioning pin was provided on the support surface of the rotating fixed part of the drive unit. However, it is also possible to position the drive unit and the transmitted optical element by providing the positioning pin on the assembly jig side rather than the drive unit side.

[0105] The following describes a modification of the manufacturing method of the light source device, specifically an assembly step in which a positioning pin is provided on the jig side, as another assembly step in the optical scanning section, which is part of the manufacturing process of the light source device. Figure 13 shows the assembly process of the first optical scanning unit when a positioning pin is provided on the jig side. As shown in Figure 13, in the first step, a jig 70 having a plurality of positioning pins P located on the same circle centered on the first rotation axis C1 is positioned coaxially with the first rotation axis C1 of the first drive unit 35. Then, as the second step, the first transmissive optical element 15, which is positioned on the jig 70, is brought into contact with the support surface 51a of the rotating fixing part 51 of the first drive unit 35. Next, in the third step, the first transmissive optical element 15 or the jig 70 is rotated in the circumferential direction of the first rotation axis C1, thereby bringing at least three of the multiple positioning pins P into contact with the first transmissive optical element 15. Finally, in the fourth step, the first transmissive optical element 15 is fixed to the support surface 51a with at least three of the positioning pins P in contact with the first transmissive optical element 15. The first optical scanning unit 60 can be assembled in this manner. Unlike the first optical scanning unit 6 of the above embodiment, this first optical scanning unit 60 does not have a plurality of positioning pins P provided on the support surface 51a side.

[0106] In other words, the assembly process of the modified example comprises: a first step of arranging a jig 70 having a plurality of positioning pins P located on the same circle centered on the first rotation axis C1 of the first drive unit 35 coaxially with the first rotation axis C1; a second step of bringing the first transmissive optical element 15 placed on the jig 70 into contact with the support surface 51a of the first drive unit 35; a third step of rotating the first transmissive optical element 15 or the jig 70 in the circumferential direction of the first rotation axis C1 so that at least three of the plurality of positioning pins P come into contact with the first transmissive optical element 15; and a fourth step of fixing the first transmissive optical element 15 to the support surface 51a while at least three of the plurality of positioning pins P are in contact with the first transmissive optical element 15.

[0107] In the first optical scanning unit 60 assembled by the assembly process shown in Figure 13, the first rotation axis C1 and the central axis of the first transmission optical element 15 can be easily and accurately aligned to suppress the occurrence of axial wobble. Therefore, by the manufacturing method of the light source device including the above assembly process, it is possible to manufacture a light source device that suppresses the generation of noise and vibration due to axial wobble of the first transmission optical element 15.

[0108] Furthermore, although the above embodiment shows an example in which the light source device according to the present invention is mounted on a projector, it is not limited to this. The light source device according to the present invention can also be applied to lighting fixtures, automobile headlights, and the like.

[0109] [Summary of this disclosure] A summary of this disclosure is provided below.

[0110] (Note 1) A light source that emits light, The system includes an optical scanning unit that periodically scans the light emitted from the light source unit, The optical scanning unit is A transmissive optical element that rotates about a rotation axis extending in a direction intersecting the direction of incidence of the light, and has an incident surface into which the light incident from the light source unit is incident, and an exit surface that emits the light incident from the incident surface, It has a drive unit for rotating the aforementioned transparent optical element, The aforementioned drive unit is A rotating fixing part that fixes the aforementioned transparent optical element so as to be rotatable around the rotation axis, The rotating fixing portion has a plurality of positioning pins arranged on the support surface of the transmissive optical element and located on the same circle centered on the rotation axis, The plurality of positioning pins include a first pin that contacts the first side surface of the transmissive optical element, a second pin that contacts the second side surface of the transmissive optical element, and a third pin that contacts the third side surface of the transmissive optical element. When, on a cross-section formed by a plane perpendicular to the axis of rotation, the intersection point of a first imaginary line perpendicular to the central axis and the first side surface of the transmissive optical element and the first side surface is defined as the first intersection point, the intersection point of a second imaginary line perpendicular to the central axis and the second side surface of the transmissive optical element and the second side surface is defined as the second intersection point, and the intersection point of a third imaginary line perpendicular to the central axis and the third side surface of the transmissive optical element and the third side surface is defined as the third intersection point, The first position of the first intersection with respect to the first pin, the second position of the second intersection with respect to the second pin, and the third position of the third intersection with respect to the third pin are each offset to one side in the circumferential direction of the axis of rotation. Light source device.

[0111] With this light source configuration, the first transmissive optical element can be fixed to the support surface of the rotation fixing part with three pins in contact with each side of the first transmissive optical element by twisting the first transmissive optical element around the rotation axis. Therefore, compared to the case where the elements are positioned off-center relative to the two positioning pins, the rotation axis and the central axis of the first transmissive optical element can be aligned simply and with high precision, suppressing the occurrence of axial runout. Consequently, with this light source configuration, the generation of noise and vibration caused by axial runout of the first transmissive optical element can be suppressed.

[0112] (Note 2) The first position, the second position, and the third position are each shifted to the opposite side of the rotation direction of the transmitted optical element. The light source device described in Appendix 1.

[0113] With this configuration, when the rotating fixing part rotates, acceleration is also generated in each pin that contacts each side surface of the transmissive optical element. As a result, each pin becomes more closely attached to each side surface of the transmissive optical element, and the transmissive optical element is held more stably by the rotating fixing part. Therefore, the detachment of the transmissive optical element from the rotating fixing part can be suppressed.

[0114] (Note 3) The first position, the second position, and the third position are each shifted toward the rotational direction side of the transmitted optical element. The light source device described in Appendix 1 or Appendix 2.

[0115] With this configuration, when the rotating fixing part rotates, acceleration is generated in a direction that moves each side of the transmissive optical element away from each pin. As a result, the acceleration due to the rotation of each pin no longer acts on each side of the transmissive optical element, thus suppressing defects such as chipping or cracking of the sides of the transmissive optical element due to stress from each pin.

[0116] (Note 4) The plurality of positioning pins further include a fourth pin facing the fourth side surface of the transmissive optical element. A light source device described in any one of the appendices 1 through 3.

[0117] With this configuration, for example, the fourth pin can contact the side surface of the transmissive optical element, thereby improving the positioning accuracy of the positioning pin.

[0118] (Note 5) The first pin, the second pin, and the third pin are each cylindrical. A light source device as described in any one of the appendices 1 through 4.

[0119] With this configuration, the contact points between the first, second, and third pins and each side surface are linear, which improves the positioning accuracy of the transmitted optical element by each pin.

[0120] (Note 6) The weight of at least one of the first pin, the second pin, and the third pin is different from the weight of the other pins. A light source device described in any one of the appendices 1 through 5.

[0121] With this configuration, even if the combined center of gravity of multiple positioning pins does not coincide with the center of gravity of the transmissive optical element, the axial misalignment between the center of gravity of the transmissive optical element and the axis of rotation can be reduced.

[0122] (Note 7) The transmitted optical element has a first surface and a second surface that intersect the axis of rotation, and 2 × m (m: a natural number of 2 or more) side surfaces that are in contact with the first surface and the second surface. The incident surface and the ejection surface are two of the 2 × m sides that are parallel to each other. A light source device as described in any one of the appendices 1 through 6.

[0123] With this configuration, since there is no light incident on the non-parallel sides, the generation of stray light in the transmitted optical element is reduced, and the light utilization efficiency can be improved.

[0124] (Note 8) A method for manufacturing a light source device that scans light by causing light emitted from a light source unit to be incident on a transmissive optical element rotated by a drive unit, A step of arranging a jig having multiple positioning pins located on the same circle centered on the rotation axis, coaxially with the rotation axis of the drive unit, A step of bringing the transmissive optical element, which is placed in the jig, into contact with the support surface of the drive unit, The process of rotating the transmissive optical element or the jig in the circumferential direction of the rotation axis so that at least three of the plurality of positioning pins come into contact with the transmissive optical element, The process includes fixing the transmissive optical element to the support surface while at least three of the plurality of positioning pins are in contact with the transmissive optical element. A method for manufacturing a light source device.

[0125] According to the manufacturing method of this light source device, the transmitted optical element can be fixed to the support surface of the rotating fixing part with the three pins in contact with each side of the transmitted optical element by twisting the transmitted optical element around the rotation axis. Therefore, compared to the case where the element is positioned off-center with respect to the two positioning pins, the rotation axis and the central axis of the transmitted optical element can be aligned simply and with high precision, suppressing the occurrence of axial runout. Accordingly, according to the manufacturing method of this light source device device, it is possible to manufacture a light source device that suppresses the generation of noise and vibration caused by axial runout of the transmitted optical element.

[0126] (Note 9) A light source device described in any one of the appendices 1 to 7, A light modulation device that modulates the light emitted from the optical scanning unit of the light source device according to image information, The system comprises a projection optical device that projects light modulated by the aforementioned optical modulation device, projector.

[0127] This projector configuration incorporates a light source that suppresses noise and vibration caused by axial wobble, resulting in a projector with superior quietness. [Explanation of Symbols]

[0128] 5, 5A, 5B, 5C, 5D, 5E, 15…Transmitting optical element, 6…Optical scanning unit, 10, 100…Light source device, 11…Light source unit, 15…First transmitting optical element (transmitting optical element), 15a…First surface, 15b…Second surface, 15c, 16c, 17c, 15c1, 15c2…Side, 15c…First side (side), 16…Second transmitting optical element (transmitting optical element), 16c…Second side (side), 17…Third transmitting optical element (transmitting optical element), 17c…Third side (side), 20…Projector, 23…Projection optical device, 35…Drive unit, 35…First drive unit (drive unit), 36…Second drive unit (drive unit), 37…Third drive unit (drive unit), 43B, 43G ,43R...Optical modulation device, 51...Rotation fixing part, 51a...Support surface, 150...Central axis, 151...First intersection, 15c1...First side surface, 152...Second intersection, 15c2...Second side surface, 153...Third intersection, 15c3...Third side surface, 15c4,16c4...Fourth side surface, C1...Rotation axis, C1...First rotation axis (rotation axis), C2...Second rotation axis (rotation axis), C3...Third rotation axis (rotation axis), K1...First virtual line, K1,K2...Second virtual line, K3...Third virtual line, P,P1...Pin, P1...First pin, P2...Second pin, P3...Third pin, P4...Fourth pin, P10,P11,P12...Positioning pin, T1...First position, T2...Second position, T3...Third position.

Claims

1. A light source that emits light, The system includes an optical scanning unit that periodically scans the light emitted from the light source unit, The optical scanning unit is A transmissive optical element that rotates about a rotation axis extending in a direction intersecting the direction of incidence of the light, and has an incident surface into which the light incident from the light source unit is incident, and an exit surface that emits the light incident from the incident surface, It has a drive unit for rotating the aforementioned transparent optical element, The aforementioned drive unit is A rotating fixing part that fixes the aforementioned transparent optical element so as to be rotatable around the rotation axis, The rotating fixing portion has a plurality of positioning pins arranged on the support surface of the transmissive optical element and located on the same circle centered on the rotation axis, The plurality of positioning pins include a first pin that abuts against the first side surface of the transmissive optical element, a second pin that abuts against the second side surface of the transmissive optical element, and a third pin that abuts against the third side surface of the transmissive optical element. When, on a cross-section formed by a plane perpendicular to the axis of rotation, the intersection point of a first imaginary line perpendicular to the central axis and the first side surface of the transmissive optical element and the first side surface is defined as the first intersection point, the intersection point of a second imaginary line perpendicular to the central axis and the second side surface of the transmissive optical element and the second side surface is defined as the second intersection point, and the intersection point of a third imaginary line perpendicular to the central axis and the third side surface of the transmissive optical element and the third side surface is defined as the third intersection point, The first position of the first intersection with respect to the first pin, the second position of the second intersection with respect to the second pin, and the third position of the third intersection with respect to the third pin are each offset to one side in the circumferential direction of the rotation axis. Light source device.

2. The first position, the second position, and the third position are each shifted to the opposite side of the rotation direction of the transmitted optical element. The light source device according to claim 1.

3. The first position, the second position, and the third position are each shifted toward the rotational direction side of the transmitted optical element. The light source device according to claim 1.

4. The plurality of positioning pins further include a fourth pin facing the fourth side surface of the transmissive optical element. The light source device according to claim 1.

5. The first pin, the second pin, and the third pin are each cylindrical. The light source device according to claim 1.

6. The weight of at least one of the first pin, the second pin, and the third pin is different from the weight of the other pins. The light source device according to claim 1.

7. The transmitted optical element has a first surface and a second surface that intersect the axis of rotation, and 2 × m (m: a natural number of 2 or more) side surfaces that are in contact with the first surface and the second surface. The incident surface and the ejection surface are two of the 2 × m sides that are parallel to each other. The light source device according to claim 1.

8. A method for manufacturing a light source device that scans light by causing light emitted from a light source unit to be incident on a transmissive optical element rotated by a drive unit, A step of arranging a jig having multiple positioning pins located on the same circle centered on the rotation axis, coaxially with the rotation axis of the drive unit, A step of bringing the transmissive optical element, which is placed in the jig, into contact with the support surface of the drive unit, The steps include: rotating the transmissive optical element or the jig in the circumferential direction of the rotation axis to bring at least three of the plurality of positioning pins into contact with the transmissive optical element; The process includes fixing the transmissive optical element to the support surface while at least three of the plurality of positioning pins are in contact with the transmissive optical element. A method for manufacturing a light source device.

9. A light source device according to any one of claims 1 to 7, A light modulation device that modulates the light emitted from the optical scanning unit of the light source device according to image information, The system comprises a projection optical device that projects light modulated by the aforementioned optical modulation device, projector.

Images