Light source device, light scanner, projector, and method for manufacturing optical element

Abstract

To provide a light source device having a simple structure and capable of generating parallel light having desired shape.SOLUTION: A light source device includes: a light source part emitting light; and an optical element obtained by laminating a plurality of transmission optical elements including first and second transmission optical elements. The first transmission optical element includes: a first incident plane making a first component of the light incident and forming a first angle to a reference plane orthogonal to the chief ray of the light; and a first emission plane emitting the first component of the light incident from the first incident plane. The second transmission optical element includes: a second incident plane making a second component different from the first component of the light incident and forming a second angle different from the first angle to the reference plane; and a second emission plane emitting the second component of the light incident from the second incident plane. In the first transmission optical element, the first incident plane and the first emission plane are parallel to each other, and in the second transmission optical element, the second incident plane and the second emission plane are parallel to each other.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a light source device, an optical scanning device, a projector, and a method for manufacturing an optical element. [Background technology]

[0002] Conventionally, there is a projector that illuminates a light modulation device such as a liquid crystal panel by scanning light emitted from a light-emitting element over time on the light modulation device. Patent Document 1 listed below discloses a projector that includes a light source device including a light source lamp, a liquid crystal light valve, a polygon mirror provided between the light source device and the liquid crystal light valve, and a projection lens. In this projector, the light source device emits light having an elliptical beam cross section. The polygon mirror reflects the light emitted from the light source device and scans the light in the minor axis direction of the elliptical beam cross section over the image formation area of ​​the liquid crystal light valve. [Prior art documents] [Patent documents]

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

[0004] In the projector of Patent Document 1, convergent light is incident on a polygon mirror from a light source device, so when the light reflected by the polygon mirror is made to enter the illuminated area as parallel light of the desired shape, optical components such as lenses are required, which increases the number of components. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, according to a first aspect of the present invention, there is provided a light source device comprising: a light source unit that emits light; and an optical element in which a plurality of transmissive optical elements including a first transmissive optical element and a second transmissive optical element are stacked; the first transmissive optical element has a first entrance surface onto which a first component of the light is incident and which forms a first angle with respect to a reference plane that is orthogonal to a chief ray of the light, and a first exit surface from which the first component of the light incident from the first entrance surface is exited; the second transmissive optical element has a second entrance surface onto which a second component different from the first component of the light is incident and which forms a second angle with respect to the reference plane which is different from the first angle, and a second exit surface from which the second component of the light incident from the second entrance surface is exited; in the first transmissive optical element, the first entrance surface and the first exit surface are parallel to each other; and in the second transmissive optical element, the second entrance surface and the second exit surface are parallel to each other.

[0006] Furthermore, according to a second aspect of the present invention, there is provided an optical scanning device, further comprising the light source device of the second aspect and a scanning optical element that rotates around an axis along the stacking direction of the plurality of transmissive optical elements and scans the light emitted from the light source device.

[0007] Furthermore, according to a third aspect of the present invention, there is provided a projector comprising the optical scanning device of the first aspect, an optical modulation device that modulates the light emitted from the optical scanning device based on image information, and a projection optical device that projects the light emitted from the optical modulation device.

[0008] According to a fourth aspect of the present invention, there is provided a first transmissive optical element made of a light-transmitting member and having a first incident surface on which a first component of light emitted from a light source unit is incident, a first exit surface from which the first component of the light incident from the first incident surface exits, and first and second surfaces intersecting with the first incident surface and the first exit surface; a second transmissive optical element made of a light-transmitting member and having a second incident surface on which a second component of the light emitted from the light source unit is incident, a second exit surface from which the second component of the light incident from the second incident surface exits, and third and fourth surfaces intersecting with the second incident surface and the second exit surface; and a third incident surface on which a third component of the light emitted from the light source unit is incident, and a third exit surface from which the third component of the light incident from the light source unit is incident, a third transmissive optical element having a third exit surface that exits the third component of the light incident from the exit surface, and fifth and sixth surfaces that intersect with the third entrance surface and the third exit surface, the method comprising: a holding step of opposing the second surface of the first transmissive optical element to the third surface of the second transmissive optical element so that the first entrance surface and the second entrance surface are non-parallel to each other, and abutting the fourth surface of the second transmissive optical element to the fifth surface of the third transmissive optical element so that the second entrance surface and the third entrance surface are non-parallel to each other; and a bonding step of bonding the first transmissive optical element, the second transmissive optical element, and the third transmissive optical element to each other. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view showing a schematic configuration of a projector according to a first embodiment. [Figure 2] FIG. 2 is a perspective view showing the configuration of a main part of the light source device of the first embodiment. [Figure 3A] FIG. 2 is a perspective view showing a configuration of a main part of an optical element. [Figure 3B] FIG. 2 is a side view showing the main configuration of the optical element. [Figure 4] FIG. 2 is a plan view of the optical element as viewed from the light incident side. [Figure 5] FIG. 1 is a diagram showing the behavior of light transmitted through one transmissive optical element. [Figure 6A] 4A and 4B are diagrams for explaining the behavior of light through a first transmissive optical element. [Figure 6B] 10A and 10B are diagrams for explaining the behavior of light through a second transmissive optical element. [Figure 6C] 10A and 10B are diagrams for explaining the behavior of light through a third transmissive optical element. [Figure 6D] 10A and 10B are diagrams for explaining the behavior of light through a fourth transmissive optical element. [Figure 6E] 10A and 10B are diagrams for explaining the behavior of light through a fifth transmissive optical element. [Figure 6F] 10A and 10B are diagrams for explaining the behavior of light through a sixth transmissive optical element. [Figure 6G] 10 is a diagram for explaining the behavior of light through a seventh transmissive optical element. FIG. [Figure 7] FIG. 2 is a conceptual diagram showing an emitted light beam emitted from an optical element. [Figure 8A] 5A and 5B are schematic diagrams for explaining the behavior of a light beam emitted by a scanning optical element. [Figure 8B] 5A and 5B are schematic diagrams for explaining the behavior of a light beam emitted by a scanning optical element. [Figure 8C] 5A and 5B are schematic diagrams for explaining the behavior of a light beam emitted by a scanning optical element. [Figure 8D] 5A and 5B are schematic diagrams for explaining the behavior of a light beam emitted by a scanning optical element. [Figure 8E] 5A and 5B are schematic diagrams for explaining the behavior of a light beam emitted by a scanning optical element. [Figure 8F] 5A and 5B are schematic diagrams for explaining the behavior of a light beam emitted by a scanning optical element. [Figure 9] FIG. 10 is a plan view showing a schematic configuration of a projector according to a second embodiment. [Figure 10] FIG. 10 is a plan view showing a schematic configuration of a projector according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) A first embodiment of the present invention will be described below with reference to the drawings. The projector of this embodiment is an example of a liquid crystal projector that uses a liquid crystal panel as a light modulation device. In the drawings below, the dimensions of some components may be shown on different scales to make them easier to see.

[0011] FIG. 1 is a plan view showing a schematic configuration of a projector according to this embodiment. 1, a projector 100 of this embodiment includes an optical scanning device 20, an optical modulation device 21, an exit-side polarizing plate 22, and a projection optical device 23. The optical scanning device 20 includes a light source device 10 and a scanning optical element 17. The light source device 10 includes a light source unit 10a and an optical element 11.

[0012] The following description will be given using an XYZ Cartesian coordinate system in the drawings as necessary. The X axis is an axis parallel to the illumination optical axis AX of the light source device 10. The illumination optical axis AX of the light source device 10 is defined as an axis along the chief ray of the light L1 emitted from the light source unit 10a. The Y axis is an axis perpendicular to the X axis and parallel to the stacking direction of the optical element 11. The Z axis is an axis perpendicular to the X axis and the Y axis.

[0013] The light source unit 10a emits light L1 in a first wavelength band toward the optical element 11. The light source unit 10a is configured with a light emitting element made of a laser diode. Therefore, the light L1 emitted from the light source unit 10a is coherent linearly polarized light, a laser beam with a narrow beam width and high parallelism. The first wavelength band is not particularly limited as long as it is within the visible light wavelength band.

[0014] The optical element 11 transmits light L1 emitted from the light source unit 10a. The optical element 11 is configured by stacking a plurality of transmissive optical elements 11a along the Y-axis direction. In this embodiment, the plurality of transmissive optical elements 11a are an integrated optical member. The method of integrating the plurality of transmissive optical elements 11a may include integration with a boundary surface by bonding, or integration without a boundary surface, such as when the plurality of transmissive optical elements 11a are machined from a single material.

[0015] Light L1 that has passed through the optical element 11 is emitted in a state containing multiple light beams, as will be described later. Hereinafter, the light L1 that is emitted by the light source device 10 after passing through the optical element 11 will be referred to as an emitted light beam LA. In the light source device 10 of this embodiment, the emitted light beam LA has a band shape whose elongated direction is in the Z-axis direction.

[0016] FIG. 2 is a perspective view showing the configuration of the main part of the light source device 10 of this embodiment. 2, the optical element 11 has a central axis O extending in the stacking direction (Y-axis direction). In the optical element 11, each transmissive optical element 11a is arranged so that its center overlaps the central axis O. The optical element 11 of this embodiment is configured by stacking seven transmissive optical elements 11a.

[0017] 3A is a perspective view showing the configuration of the main part of optical element 11. FIG. 3B is a side view showing the configuration of the main part of optical element 11. Hereinafter, when distinguishing between the seven transmissive optical elements 11a, they will be referred to as the first transmissive optical element, the second transmissive optical element, the third transmissive optical element, the fourth transmissive optical element, the fifth transmissive optical element, the sixth transmissive optical element, and the seventh transmissive optical element. 3A and 3B, the multiple transmissive optical elements 11a include a first transmissive optical element 41, a second transmissive optical element 42, a third transmissive optical element 43, a fourth transmissive optical element 44, a fifth transmissive optical element 45, a sixth transmissive optical element 46, and a seventh transmissive optical element 47. The first transmissive optical element 41, the second transmissive optical element 42, the third transmissive optical element 43, the fourth transmissive optical element 44, the fifth transmissive optical element 45, the sixth transmissive optical element 46, and the seventh transmissive optical element 47 may be collectively referred to as each optical element 41 to 47. Note that each optical element 41 to 47 corresponds to the transmissive optical elements 11a stacked in order from the +Y side to the -Y side.

[0018] Each of the optical elements 41 to 47 has the same shape. That is, each of the optical elements 41 to 47 has the same thickness and area, and is made of a thin, light-transmitting member having a square planar shape. As the glass material of the optical members that make up the optical element 11, for example, optical glass such as BK7, quartz, resin, or other light-transmitting materials are used. In this way, each of the optical elements 41 to 47 is made of the same material and has the same shape. Therefore, the refractive indexes of each of the optical elements 41 to 47 are equal to one another. This makes it easy to align the refraction angles of light passing through each of the optical elements 41 to 47. This makes it easy to adjust the optical path of light passing through the optical element 11. Furthermore, the optical elements 41 to 47 are equal in size, such as thickness and area, so that the optical elements 41 to 47 can use the same components, improving the ease of assembly of the optical element 11 and reducing costs.

[0019] In the stacking direction of the optical element 11, the optical elements 41 to 47 are arranged such that their centers overlap on the central axis O. Therefore, the optical elements 41 to 47 are aligned with each other with high precision, which makes it easy to align the optical elements 41 to 47 that make up the optical element 11 with the illumination optical axis AX.

[0020] The first transmissive optical element 41 has a first surface 41a and a second surface 41b that are orthogonal to the stacking direction (Y-axis direction), and four first side surfaces 41c1, 41c2, 41c3, and 41c4 that are perpendicular to the first surface 41a and the second surface 41b. The four first side surfaces 41c1, 41c2, 41c3, and 41c4 have the same area, and two opposing first side surfaces are parallel to each other. The first surface 41a faces the +Y side. The second surface 41b faces the -Y side and is integrated with the second transmissive optical element 42.

[0021] The second transmissive optical element 42 has a third surface 42a and a fourth surface 42b that are orthogonal to the stacking direction (Y-axis direction), and four second side surfaces 42c1, 42c2, 42c3, and 42c4 that are perpendicular to the third surface 42a and the fourth surface 42b. The four second side surfaces 42c1, 42c2, 42c3, and 42c4 have the same area, and two opposing second side surfaces are parallel to each other. The third surface 42a faces the +Y side and is integrated with the second surface 41b of the first transmissive optical element 41. The fourth surface 42b faces the -Y side, opposite the third surface 42a.

[0022] The third transmissive optical element 43 has a fifth surface 43a and a sixth surface 43b that are orthogonal to the stacking direction (Y-axis direction), and four third side surfaces 43c1, 43c2, 43c3, and 43c4 that are perpendicular to the fifth surface 43a and the sixth surface 43b. The four third side surfaces 43c1, 43c2, 43c3, and 43c4 have the same area, and two opposing third side surfaces are parallel to each other. The fifth surface 43a faces the +Y side and is integrated with the fourth surface 42b of the second transmissive optical element 42. The sixth surface 43b faces the -Y side, opposite the fifth surface 43a.

[0023] The fourth transmissive optical element 44 has a seventh surface 44a and an eighth surface 44b that are orthogonal to the stacking direction (Y-axis direction), and four fourth side surfaces 44c1, 44c2, 44c3, and 44c4 that are perpendicular to the seventh surface 44a and the eighth surface 44b. The four fourth side surfaces 44c1, 44c2, 44c3, and 44c4 have the same area, and two opposing fourth side surfaces are parallel to each other. The seventh surface 44a faces the +Y side and is integrated with the sixth surface 43b of the third transmissive optical element 43. The eighth surface 44b faces the -Y side, opposite the seventh surface 44a.

[0024] The fifth transmissive optical element 45 has a ninth surface 45a and a tenth surface 45b that are orthogonal to the stacking direction (Y-axis direction), and four fifth side surfaces 45c1, 45c2, 45c3, and 45c4 that are perpendicular to the ninth surface 45a and the tenth surface 45b. The four fifth side surfaces 45c1, 45c2, 45c3, and 45c4 have the same area, and two opposing fifth side surfaces are parallel to each other. The ninth surface 45a faces the +Y side and is integrated with the eighth surface 44b of the fourth transmissive optical element 44. The tenth surface 45b faces the -Y side, opposite the ninth surface 45a.

[0025] The sixth transmissive optical element 46 has an eleventh surface 46a and a twelfth surface 46b that are orthogonal to the stacking direction (Y-axis direction), and four sixth side surfaces 46c1, 46c2, 46c3, and 46c4 that are perpendicular to the eleventh surface 46a and the twelfth surface 46b. The four sixth side surfaces 46c1, 46c2, 46c3, and 46c4 have the same area, and two opposing sixth side surfaces are parallel to each other. The eleventh surface 46a faces the +Y side and is integrated with the tenth surface 45b of the fifth transmissive optical element 45. The twelfth surface 46b faces the -Y side, opposite the eleventh surface 46a.

[0026] The seventh transmissive optical element 47 has a thirteenth surface 47a and a fourteenth surface 47b that are orthogonal to the stacking direction (Y-axis direction), and four seventh side surfaces 47c1, 47c2, 47c3, and 47c4 that are perpendicular to the thirteenth surface 47a and the fourteenth surface 47b. The four seventh side surfaces 47c1, 47c2, 47c3, and 47c4 have the same area, and two opposing seventh side surfaces are parallel to each other. The thirteenth surface 47a faces the +Y side and is integrated with the twelfth surface 46b of the sixth transmissive optical element 46. The fourteenth surface 47b faces the -Y side, opposite the thirteenth surface 47a.

[0027] In the present embodiment, the number of side surfaces of each of the optical elements 41 to 47 is four, but the number of side surfaces of each of the optical elements 41 to 47 does not necessarily have to be four. Also, the number of side surfaces of each of the optical elements 41 to 47 does not necessarily have to be the same. In other words, the cross-sectional shapes of each of the optical elements 41 to 47 may be different.

[0028] For example, the number of first side surfaces of the first transmissive optical element 41 is preferably 2×m (m: a natural number equal to or greater than 2), and the number of second side surfaces of the second transmissive optical element 42 is preferably 2×n (n: a natural number equal to or greater than 2). That is, the number of first side surfaces and second side surfaces is preferably an even number, such as 6 or 8. If the number of first side surfaces and second side surfaces is an even number, all of the first side surfaces and second side surfaces are parallel to the first side surfaces and second side surfaces opposite to them, and there are no first side surfaces and second side surfaces that are not parallel. This reduces the generation of stray light in the first transmissive optical element 41 and the second transmissive optical element 42, thereby improving light utilization efficiency. Similarly to the first transmissive optical element 41 and the second transmissive optical element 42, the other transmissive optical elements 43 to 47 may have different shapes as long as they have an even number of side surfaces.

[0029] The optical element 11 transmits the light L1 emitted from the light source unit 10a. 4 is a plan view of the optical element 11 as viewed from the light incident side. In FIG. 4, an example is shown in which the light L1 forms a circular spot on the optical element 11, but the shape of the spot of the light L1 is not particularly limited as long as it does not extend beyond the optical element 11.

[0030] 4, the optical element 11 has a width equal to or greater than the beam width of the light L1. Therefore, the light L1 is incident on the optical element 11 so as to straddle the boundaries of the optical elements 41 to 47 in the stacking direction (Y-axis direction). In this embodiment, the chief ray of the light L1 is positioned at the center in the stacking direction and is incident on the fourth transmissive optical element 44.

[0031] Here, of the light L1 emitted from the light source unit 10a, the component that enters the first transmissive optical element 41 is referred to as the first component L11, the component that enters the second transmissive optical element 42 is referred to as the second component L12, the component that enters the third transmissive optical element 43 is referred to as the third component L13, the component that enters the fourth transmissive optical element 44 is referred to as the fourth component L14, the component that enters the fifth transmissive optical element 45 is referred to as the fifth component L15, the component that enters the sixth transmissive optical element 46 is referred to as the sixth component L16, and the component that enters the seventh transmissive optical element 47 is referred to as the seventh component L17.

[0032] In the first transmissive optical element 41, the first side surface onto which the first component L11 is incident is referred to as the first incident surface, and the first side surface opposite to the first incident surface from which the first component L11 incident from the first incident surface exits is referred to as the first exit surface. In the second transmissive optical element 42, the second side surface onto which the second component L12 is incident is referred to as the second incident surface, and the second side surface opposite to the second incident surface from which the second component L12 incident from the second incident surface is emitted is referred to as the second exit surface. In the third transmissive optical element 43, the third side surface onto which the third component L13 is incident is referred to as the third incident surface, and the third side surface opposite to the third incident surface from which the third component L13 incident from the third incident surface is emitted is referred to as the third exit surface. In the fourth transmitting optical element 44, the fourth side surface onto which the fourth component L14 is incident is referred to as the fourth entrance surface, and the fourth side surface opposite to the fourth entrance surface from which the fourth component L14 incident from the fourth entrance surface is emitted is referred to as the fourth exit surface. In the fifth transmissive optical element 45, the fifth side surface onto which the fifth component L15 is incident is referred to as the fifth entrance surface, and the fifth side surface opposite to the fifth entrance surface from which the fifth component L15 incident from the fifth entrance surface exits is referred to as the fifth exit surface. In the sixth transmitting optical element 46, the sixth side surface onto which the sixth component L16 is incident is referred to as the sixth entrance surface, and the sixth side surface opposite to the sixth entrance surface from which the sixth component L16 incident from the sixth entrance surface emerges is referred to as the sixth exit surface. In the seventh transmitting optical element 47, the seventh side surface onto which the seventh component L17 is incident is referred to as the seventh incident surface, and the seventh side surface opposite to the seventh incident surface from which the seventh component L17 incident from the seventh incident surface emerges is referred to as the seventh exit surface.

[0033] Here, the light L1, which is a laser beam, is a Gaussian beam, and therefore has a higher light intensity at the center than at the periphery. That is, when the light L1 enters the optical element 11, the light intensity is highest in the portion closest to the illumination optical axis AX, and decreases with increasing distance from the illumination optical axis AX. In this embodiment, the light intensities of the first and seventh components L11 and L17 of the light L1, which are furthest from the illumination optical axis AX, are lowest. Meanwhile, the light intensity of the fourth component L14 of the light L1, which is located on the illumination optical axis AX, is highest. The light intensities of the third and fifth components L13 and L15, which are farther from the illumination optical axis AX than the fourth component L14, are lower than the fourth component L14. The second and sixth components L12 and L16, which are farther from the illumination optical axis AX than the third and fifth components L13 and L15, have light intensities between the light intensities of the third and fifth components L13 and L15 and the first and seventh components L17.

[0034] 3B, in the first transmissive optical element 41, of the four first side surfaces 41c1, 41c2, 41c3, and 41c4, the first side surface 41c1 corresponds to the first incident surface 410, and the first side surface 41c3 parallel to the first side surface 41c1 corresponds to the first exit surface 411. In other words, the first incident surface 410 and the first exit surface 411 are two first side surfaces that are parallel to each other among the four first side surfaces 41c1, 41c2, 41c3, and 41c4.

[0035] Furthermore, in the second transmissive optical element 42, of the four second side surfaces 42c1, 42c2, 42c3, and 42c4, the second side surface 42c1 corresponds to the second incident surface 420, and the second side surface 42c3 parallel to the second side surface 42c1 corresponds to the second exit surface 421. In other words, the second incident surface 420 and the second exit surface 421 are two second side surfaces that are parallel to each other among the four second side surfaces 42c1, 42c2, 42c3, and 42c4.

[0036] Furthermore, in the third transmissive optical element 43, the third side surface 43c1 of the four third side surfaces 43c1, 43c2, 43c3, and 43c4 corresponds to the third incident surface 430, and the third side surface 43c3 parallel to the third side surface 43c1 corresponds to the third exit surface 431. In other words, the third incident surface 430 and the third exit surface 431 are two third side surfaces that are parallel to each other among the four third side surfaces 43c1, 43c2, 43c3, and 43c4.

[0037] In the fourth transmissive optical element 44, the fourth side surface 44c1 of the four fourth side surfaces 44c1, 44c2, 44c3, and 44c4 corresponds to the fourth incident surface 440, and the fourth side surface 44c3 parallel to the fourth side surface 44c1 corresponds to the fourth exit surface 441. That is, the fourth incident surface 440 and the fourth exit surface 441 are two fourth side surfaces of the four fourth side surfaces 44c1, 44c2, 44c3, and 44c4 that are parallel to each other. Note that, in the fourth transmissive optical element 44, as described below, the fourth side surface 44c2 of the four fourth side surfaces 44c1, 44c2, 44c3, and 44c4 also corresponds to the fourth incident surface 440, and the fourth side surface 44c4 parallel to the fourth side surface 44c2 corresponds to the fourth exit surface 441.

[0038] Furthermore, in the fifth transmissive optical element 45, the fifth side surface 45c1 of the four fifth side surfaces 45c1, 45c2, 45c3, and 45c4 corresponds to the fifth entrance surface 450, and the fifth side surface 45c3 parallel to the fifth side surface 45c1 corresponds to the fifth exit surface 451. In other words, the fifth entrance surface 450 and the fifth exit surface 451 are two fifth side surfaces that are parallel to each other among the four fifth side surfaces 45c1, 45c2, 45c3, and 45c4.

[0039] Furthermore, in the sixth transmissive optical element 46, the sixth side surface 46c1 of the four sixth side surfaces 46c1, 46c2, 46c3, and 46c4 corresponds to the sixth incident surface 460, and the sixth side surface 46c3 parallel to the sixth side surface 46c1 corresponds to the sixth exit surface 461. In other words, the sixth incident surface 460 and the sixth exit surface 461 are two sixth side surfaces that are parallel to each other among the four sixth side surfaces 46c1, 46c2, 46c3, and 46c4.

[0040] Furthermore, in the seventh transmissive optical element 47, the seventh side surface 47c1 of the four seventh side surfaces 47c1, 47c2, 47c3, and 47c4 corresponds to the seventh incident surface 470, and the seventh side surface 47c3 parallel to the seventh side surface 47c1 corresponds to the seventh exit surface 471. In other words, the seventh incident surface 470 and the seventh exit surface 471 are two seventh side surfaces that are parallel to each other of the four seventh side surfaces 47c1, 47c2, 47c3, and 47c4.

[0041] 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 said to be in the range of 0±5 degrees, taking into consideration the processing accuracy of the glass material that makes up the optical element, the allowable range of parallelism of light, etc.

[0042] In the optical element 11, the optical elements 41 to 47 are positioned differently around the central axis O when viewed in the stacking direction (Y-axis direction). Here, an imaginary plane parallel to the YZ plane that is perpendicular to the principal ray along the optical axis of the light L1 that is incident on the optical element 11 is defined as a reference plane RP. The angle that the first incident surface 410 makes with respect to the reference plane RP is defined as the first angle θ1, the angle that the second incident surface 420 makes with respect to the reference plane RP is defined as the second angle θ2, the angle that the third incident surface 430 makes with respect to the reference plane RP is defined as the third angle θ3, the angle that the fourth incident surface 440 makes with respect to the reference plane RP is defined as the fourth angle θ4, the angle that the fifth incident surface 450 makes with respect to the reference plane RP is defined as the fifth angle θ5, the angle that the sixth incident surface 460 makes with respect to the reference plane RP is defined as the sixth angle θ6, and the angle that the seventh incident surface 470 makes with respect to the reference plane RP is defined as the seventh angle θ7.

[0043] Here, in this specification, the inclination of the illumination optical axis AX on the -Z side relative to the reference plane RP is indicated by a "+" angle, and the inclination of the illumination optical axis AX on the +Z side relative to the reference plane RP is indicated by a "-" angle. In this case, the first angle θ1 is 0 degrees, the second angle θ2 is 15 degrees, the third angle θ3 is 30 degrees, the fourth angle θ4 is 45 degrees, the fifth angle θ5 is -30 degrees, the sixth angle θ6 is -15 degrees, and the seventh angle θ7 is 0 degrees.

[0044] The optical element 11 of this embodiment is equivalent to a configuration in which the positions of the optical elements 41 to 47 are rotated relative to one another by, for example, 15 degrees clockwise in the stacking direction of the optical elements 41 to 47 with respect to the central axis O. In other words, the optical element 11 has a configuration in which the optical elements 41 to 47 are rotated by an equal angle (15 degrees) in the stacking direction and the optical elements 41 and 47 located at both ends are arranged in a twisted state by 90 degrees.

[0045] As described above, in the optical element 11 of this embodiment, the angle between two adjacent optical elements among the optical elements 41-47, for example, the angle between the first incident surface 410 of the first transmissive optical element 41 and the second incident surface 420 of the second transmissive optical element 42, and the angle between the second incident surface 420 of the second transmissive optical element 42 and the third incident surface 430 of the third transmissive optical element 43, are both 15 degrees. Therefore, in the optical element 11 of this embodiment, the angle between the incident surfaces of two adjacent optical elements among the optical elements 41-47 is constant at 15 degrees. Therefore, the amount of displacement on the illuminated area of ​​the light transmitted through the two adjacent optical elements can be changed at a constant rate. This facilitates improving the uniformity of the illuminance distribution of the light transmitted through the optical element 11.

[0046] Here, a method for manufacturing the optical element 11 will be described. The method for manufacturing the optical element 11 of this embodiment includes a holding step and a bonding step. In the holding step, the second surface 41b of the first transmissive optical element 41 and the third surface 42a of the second transmissive optical element 42 are opposed to each other so that the first incident surface 410 of the first transmissive optical element 41 and the second incident surface 420 of the second transmissive optical element 42 are non-parallel to each other. At this time, an ultraviolet-curing adhesive is disposed between the second surface 41b of the first transmissive optical element 41 and the third surface 42a of the second transmissive optical element 42. Furthermore, the fourth surface 42b of the second transmissive optical element 42 and the fifth surface 43a of the third transmissive optical element 43 are opposed to each other so that the second incident surface 420 of the second transmissive optical element 42 and the third incident surface 430 of the third transmissive optical element 43 are non-parallel to each other. At this time, an ultraviolet-curing adhesive is disposed between the fourth surface 42b of the second transmissive optical element 42 and the fifth surface 43a of the third transmissive optical element 43. Similarly, the optical elements 41 to 47 are arranged to face each other with adhesive sandwiched between them so that the entrance surfaces of adjacent optical elements are not parallel to each other. According to this configuration, the optical elements 41 to 47 can be bonded together by a simple process such as ultraviolet irradiation.

[0047] Subsequently, in the bonding step, the optical elements 41 to 47 are bonded together. The bonding step includes a holding step, a checking step, an adjusting step, and a curing step. In the holding step, each of the optical elements 41 to 47 is held at a position that does not interfere with the optical axis of the laminate made up of the optical elements 41 to 47. According to this configuration, the optical elements 41 to 47 can be held without interfering with the optical axis of the laminate, thereby preventing the occurrence of problems such as the holding members for holding the optical elements 41 to 47 interfering with the confirmation light for confirming the quality of the optical element 11. The holding step is realized, for example, by holding the corners of each of the optical elements 41 to 47 in a diagonal direction with a pair of holding members.

[0048] The checking step involves irradiating the laminate held in the holding step with checking light of a wavelength band that does not harden the adhesive, and checking the illuminance distribution of the checking light emitted from the laminate. According to this configuration, the confirmation light is not blocked by the holding members that hold the optical elements 41 to 47. Therefore, the quality inspection of the laminate using the confirmation light can be performed satisfactorily, and high-quality optical elements 11 can be manufactured.

[0049] In the adjusting step, the positions of the optical elements 41 to 47 constituting the laminate are adjusted based on the results of the checking step, and then the checking step is carried out using the laminate after the positions have been adjusted. According to this configuration, the quality of the optical element 11 can be further improved by repeating the adjustment step and the checking step.

[0050] In the curing step, if the illuminance distribution of the confirmation light meets a reference value in the adjustment step, ultraviolet light is irradiated onto the laminate that meets the reference value, and the adhesive is cured to bond each optical element together, thereby producing the optical element 11. This configuration allows the bonding process to be easily carried out by curing the adhesive with ultraviolet light. Furthermore, since the adhesive of the laminated body that satisfies the standard value is cured, the occurrence of manufacturing defects in the optical element can be minimized.

[0051] In this way, the optical element 11 of this embodiment can be manufactured easily and with high precision.

[0052] Next, the behavior of light L1 transmitted through the optical element 11 will be described. Here, the behavior of light L1 transmitted through any one of the multiple transmissive optical elements 11a that make up the optical element 11 will be described. FIG. 5 is a diagram showing the behavior of light L transmitted through one transmissive optical element 11a. In FIG. 5, the illumination optical axis AX of the light source unit (not shown) passes through the central axis O of the optical element 11, and the transmissive optical element 11a is disposed in a state rotated by a predetermined angle around the central axis O. The length of one side of the transmissive optical element 11a is taken as l. Note that light L1 has a predetermined luminous flux width in the Z-axis direction, but here we will focus on the behavior of light ray L1a traveling on the illumination optical axis AX.

[0053] As shown in FIG. 5, the light ray L1a travels parallel to the illumination optical axis AX and strikes the incident surface 12 of the transmitting optical element 11a at a point P1 at an incident angle θ 11 and the refraction angle is θ 12 After being refracted at point P2, the light emerges from the exit surface 13 of the transmissive optical element 11a and travels parallel to the illumination optical axis AX.

[0054] The light ray L1a transmitted through the transmitting optical element 11a travels parallel to the illumination optical axis AX at a position shifted by a displacement amount d corresponding to the rotation angle of the transmitting optical element 11a in a direction perpendicular to (intersecting) the illumination optical axis AX. Therefore, the displacement amount d of the light ray L1a and the incident angle θ 11 and the refraction angle θ 12 According to Snell's law, the following equation (1) holds between

[0055]

number

[0056] In this way, the transmissive optical element 11a can adjust the amount of displacement of the light ray L1a emitted from the emission surface 13 by varying the incident angle θ1 of the light ray L1a with respect to the incidence surface 11a1 according to the rotation angle around the central axis O. The maximum incident angle of the light ray L1a is determined by the cross-sectional shape of the transmissive optical element 11a, i.e., the number of side surfaces. When the cross-sectional shape of the transmissive optical element 11a is square, as in this embodiment, the maximum incident angle is 45 degrees.

[0057] The behavior of light through each of the optical elements 41 to 47 will be described below with reference to Figures 6A to 6G. Figures 6A to 6G are diagrams for explaining the behavior of light L1 through each of the optical elements 41 to 47. Note that, in Figures 6A to 6G, for ease of viewing, only the chief ray of each component incident on each of the optical elements 41 to 47 is shown, and each is shown as a single light ray.

[0058] 6A, the first component L11 is perpendicularly incident on the first side surface 41c1 of the first transmissive optical element 41, and therefore travels along the illumination optical axis AX inside the first transmissive optical element 41 without being refracted at the first side surface 41c1. Next, the first component L11 is perpendicularly incident on the first side surface 41c3 that is parallel to the first side surface 41c1. Therefore, the first component L11 is emitted from the first transmissive optical element 41 without being refracted at the first side surface 41c3 either, and travels along the illumination optical axis AX. In other words, the displacement of the first component L11 from the illumination optical axis AX is 0 (zero).

[0059] 6B, the second transmissive optical element 42 is disposed in a rotated state around the central axis O so that the second side surface 42c1 of the second transmissive optical element 42 forms a second angle θ2 (15 degrees) with respect to the reference plane RP. Therefore, the second component L12 is incident on the second side surface 42c1 at an incident angle of the second angle θ2. The second component L12 is refracted in the direction shown in the figure (toward the +Z side) and travels inside the second transmissive optical element 42. Next, the second component L12 is refracted at the second side surface 42c3 and emerges from the second transmissive optical element 42. At this time, because the second side surface 42c1 and the second side surface 42c3 are parallel to each other, the refraction angle at the time of incidence on the second side surface 42c1 and the refraction angle at the time of emergence from the second side surface 42c3 cancel each other out. As a result, the second component L12 travels parallel to the illumination optical axis AX at a position displaced from the illumination optical axis AX to the +Z side by a displacement amount d2.

[0060] 6C, the third transmissive optical element 43 is disposed in a state rotated around the central axis O so that the third side surface 43c1 of the third transmissive optical element 43 forms a third angle θ3 (30 degrees) with respect to the reference plane RP. Therefore, the displacement d3 of the third component L13 from the illumination optical axis AX becomes larger than in FIG. 6B (d3>d2).

[0061] 6D, the fourth transmissive optical element 44 is disposed in a rotated state around the central axis O so that the fourth side surface 44c1 of the fourth transmissive optical element 44 forms a fourth angle θ4 (45 degrees) with respect to the reference plane RP. As a result, the illumination optical axis AX straddles the boundary between the fourth side surface 44c1 and the fourth side surface 44c4, and the fourth component L14 is incident on both the fourth side surface 44c1 and the fourth side surface 44c4. The amount of displacement d41 from the illumination optical axis AX of the part of the fourth component L14 incident on the fourth side surface 44c1 is larger than in FIG. 6C (d41>d3).

[0062] 6D, because the fourth side surface 44c4 forms a fourth angle θ4 (−45 degrees) with respect to the reference plane RP, another portion of the fourth component L14 incident on the fourth side surface 44c4 is refracted in the direction shown in the figure (toward the −Z direction), travels inside the fourth transmissive optical element 44, is refracted at the fourth side surface 44c4, and is emitted from the fourth transmissive optical element 44. Another portion of the fourth component L14 travels parallel to the illumination optical axis AX at a position displaced from the illumination optical axis AX toward the −Z direction by a displacement amount d42. Note that the displacement amounts d42 and d41 are in opposite directions but have the same absolute value. In this way, the fourth component L14 incident on the fourth transmissive optical element 44 is split into two in the Z-axis direction perpendicular to the illumination optical axis AX. In this way, the two fourth components L14 separated by transmitting through the fourth transmitting optical element 44 are the furthest away from the illumination optical axis AX and travel parallel to the illumination optical axis AX at positions on either side of the illumination optical axis AX.

[0063] 6E, the fifth transmissive optical element 45 is disposed in a rotated state around the central axis O so that the fifth side surface 45c1 of the fifth transmissive optical element 45 forms a fifth angle θ5 (−30 degrees) with respect to the reference plane RP. Therefore, the displacement amount d5 of the fifth component L15 from the illumination optical axis AX has the same absolute value as the displacement amount d3 shown in FIG. 6C, but the displacement direction is opposite.

[0064] 6F, the sixth transmissive optical element 46 is disposed in a state rotated around the central axis O so that the sixth side surface 46c4 of the sixth transmissive optical element 46 forms a sixth angle θ6 (−15 degrees) with respect to the reference plane RP. Therefore, the displacement amount d6 of the sixth component L16 from the illumination optical axis AX has the same absolute value as the displacement amount d2 shown in FIG. 6B, but the displacement direction is opposite.

[0065] 6G, the seventh transmissive optical element 47 is disposed in a state rotated around the central axis O so that the seventh side surface 47c4 of the seventh transmissive optical element 47 forms a seventh angle θ7 (0 degrees) with respect to the reference plane RP. Therefore, the seventh component L17 is transmitted through the seventh transmissive optical element 47 as is without being refracted, and is emitted, and travels on the illumination optical axis AX.

[0066] Fig. 7 is a conceptual diagram showing the emitted light beam LA emitted from the optical element 11. In Fig. 7, the light intensity of each of the light beams LA1 to LA7 is indicated by the shade of hatching, with the darker the hatching, the stronger the light intensity, and the lighter the hatching, the weaker the light intensity. 7, the emitted light beam LA has a band shape elongated in the Z-axis direction. The emitted light beam LA includes a first light beam LA1 consisting of a first component L11, a second light beam LA2 consisting of a second component L12, a third light beam LA3 consisting of a third component L13, a fourth light beam LA4 consisting of a fourth component L14, a fifth light beam LA5 consisting of a fifth component L15, a sixth light beam LA6 consisting of a sixth component L16, and a seventh light beam LA7 consisting of a seventh component L17. Since the light beams LA1 to LA7 emitted from the optical element 11 are parallel light beams, the emitted light beam LA is made up of parallel light beams. In FIG. 7, for ease of viewing, the light beams LA1 to LA7 constituting the emitted light beam LA are shown completely separated, but adjacent light beams partially overlap each other in the Y-axis direction.

[0067] The light source device 10 of this embodiment uses the optical element 11 in which the optical elements 41 to 47 are stacked, and is thereby able to generate an emitted light beam LA consisting of approximately strip-shaped parallel light beams elongated in the Z direction. That is, the dimension of the long side of the emitted light beam LA emitted from the optical element 11 is different from the dimension of the long side of the light L1 at the time of incidence on the optical element 11. In this embodiment, the dimension of the long side of the emitted light beam LA is longer than the dimension of the long side of the light L1. According to the light source device 10 of this embodiment, parallel light having a desired band shape can be generated with a simple configuration.

[0068] As described above, the light intensity of each component of light L1 increases in the order of the first component L11 and the seventh component L17, the second component L12 and the sixth component L16, the third component L13 and the fifth component L15, and the fourth component L14. Therefore, in the emitted light beam LA, the light intensity of the fourth light beam LA4 is the highest, followed by the light intensities of the third light beam LA3 and the fifth light beam LA5, then the light intensities of the second light beam LA2 and the sixth light beam LA6, and the light intensities of the first light beam LA1 and the seventh light beam LA7 are the lowest.

[0069] In the optical element 11 of this embodiment, the optical elements 41 to 47 are arranged in consideration of the light intensity of the incident light L1. For example, by arranging a fourth transmitting optical element 44 whose light incident surface is greatly inclined with respect to the reference plane RP in the region where the fourth component L14 of the light L1, which has a high light intensity, is incident, the fourth component L14 is largely displaced and moved to the peripheral portion. Also, by arranging the fourth transmitting optical element 44 and the seventh transmitting optical element 47 whose light incident surfaces are parallel to the reference plane RP in the region where the first component L11 and the seventh component L17 of the light L1, which have a low light intensity, are incident, the first component L11 and the seventh component L17 are transmitted without being displaced and positioned in the central portion.

[0070] Therefore, in the Z-axis direction, the first light beam LA1 and the seventh light beam LA7 are located in the central part of the emitted light beam LA, and the fourth light beam LA4 is located in the peripheral part of the emitted light beam LA. Furthermore, from the central part to the peripheral part of the emitted light beam LA, the second component L12 and the sixth light beam LA6, and the third component L13 and the fifth light beam LA5 are located in this order.

[0071] In the Z-axis direction, the emitted light beam LA has a light beam with a relatively high light intensity located at the periphery and a region with a relatively low light intensity located from the central part to the periphery, so the uniformity of the light intensity is improved compared to the light intensity distribution of the light L1 consisting of a Gaussian beam at the time of incidence on the optical element 11. As described above, according to the light source device 10 of this embodiment, by optimally arranging the optical elements 41 to 47 that make up the optical element 11, it is possible to generate a strip of parallel light that illuminates the illuminated area with uniform light intensity.

[0072] The light beam LA emitted from the light source device 10 is incident on the scanning optical element 17 . The scanning optical element 17 is provided on the light emission side of the light source device 10 on the illumination optical axis AX. The scanning optical element 17 transmits the emitted light beam LA emitted from the light source device 10. The scanning optical element 17 is made of a cubic, light-transmitting member that is rotatably supported. The scanning optical element 17 is rotatable about a rotation axis C that extends along the Z-axis direction that intersects with the stacking direction (Y-axis direction) of the optical element 11. The rotation axis C is connected to a rotation drive unit 16 that is formed of a motor or the like. The scanning optical element 17 rotates about the rotation axis C by being driven by the rotation drive unit 16. As a result, the scanning optical element 17 scans the band-shaped emitted light beam LA in the Y-axis direction that is perpendicular to the longitudinal direction. In this way, the optical scanning device 20 of this embodiment scans the belt-shaped emitted light beam LA emitted from the light source device 10 by the scanning optical element 17 within a two-dimensional illuminated area of ​​the light modulation device 21, which is the illuminated surface.

[0073] The light-transmitting member constituting the scanning optical element 17 is substantially the same as the light-transmitting member constituting the optical element 11. As the glass material of the light-transmitting member, for example, optical glass such as BK7, quartz, resin, or other light-transmitting materials are used. In particular, in the case of the scanning optical element 17, since light L1 that has passed through the optical element 11 enters, the light density is lower than that of light L1 at the time of entering the optical element 11. Therefore, there is a higher possibility that a resin material with low light resistance and heat resistance can be used than in the optical element 11.

[0074] The scanning optical element 17 rotates about a rotation axis C and transmits the emitted light beam LA emitted from the light source device 10. Therefore, the outer surface onto which the emitted light beam LA enters the scanning optical element 17 is not fixed but changes over time. In the scanning optical element 17, the outer surface onto which the emitted light beam LA enters is referred to as the incident surface. In this case, the incident surface changes over time and is one of the four outer surfaces 17c1, 17c2, 17c3, and 17c4 that intersects with the illumination optical axis AX of the light source device 10.

[0075] The behavior of the emitted light beam LA when passing through the scanning optical element 17 will be described below. 8A to 8F are schematic diagrams for explaining the behavior of the emitted light beam LA when the scanning optical element 17 rotates. In this example, when viewed from the +Y side, the scanning optical element 17 rotates clockwise around the rotation axis C, and the time elapses from FIG. 8A to FIG. 8F.

[0076] 8A to 8F, the angle formed between the illumination optical axis AX and a straight line M that passes through the rotation axis C and is perpendicular to the outer surface 17c1 of the scanning optical element 17 is defined as the rotation angle ω of the scanning optical element 17. In reality, the emitted light beam LA has a predetermined light beam width in the Z-axis direction, but here we will focus on the behavior of the light ray LL, which is the chief ray traveling on the illumination optical axis AX.

[0077] 8A shows the initial state of the scanning optical element 17. That is, the scanning optical element 17 is not rotating, the straight line M and the illumination optical axis AX overlap, and the rotation angle ω is 0 degrees. In this case, the light ray LL is incident perpendicularly on the outer surface 17c1, and therefore travels along the illumination optical axis AX inside the scanning optical element 17 without being refracted at the outer surface 17c1. Next, the light ray LL is also incident perpendicularly on the outer surface 17c3, which is parallel to the outer surface 17c1. Therefore, the light ray LL is emitted from the scanning optical element 17 without being refracted at the outer surface 17c3 either, and travels along the illumination optical axis AX.

[0078] Next, as shown in FIG. 8B , when scanning optical element 17 rotates by rotation angle ω, light ray LL is incident on outer surface 17c1 at an angle of incidence equal to rotation angle ω. Therefore, light ray LL is refracted in the direction shown in the figure (toward the +Y direction) and travels inside scanning optical element 17. Next, light ray LL is incident on outer surface 17c3 at a predetermined angle of incidence, is refracted at outer surface 17c3, and is emitted from scanning optical element 17. At this time, because outer surfaces 17c1 and 17c3 are parallel to each other, the angle of incidence of light ray LL on outer surface 17c1 and the angle of incidence of light ray LL on outer surface 17c3 are equal, and the refraction angle of light ray LL incident on outer surface 17c1 and the refraction angle of light ray LL emitted from outer surface 17c3 have opposite signs but equal absolute values. This causes the angle of refraction of light ray LL when it enters outer surface 17c1 to cancel out the angle of refraction when it emerges from outer surface 17c3. As a result, light ray LL travels parallel to illumination optical axis AX at a position displaced by displacement amount d from illumination optical axis AX toward the +Y side.

[0079] Next, as shown in Figure 8C, when the rotation angle ω of the scanning optical element 17 becomes larger than that in Figure 8B, the angle of incidence of the light ray LL becomes larger, and the angle of refraction also becomes larger. Therefore, the displacement d of the light ray LL from the illumination optical axis AX becomes larger than that in Figure 8B. Furthermore, the state in which the light ray LL travels parallel to the illumination optical axis AX is always maintained. When the rotation angle ω is between 0 degrees and 45 degrees, the displacement d increases monotonically as the rotation angle ω increases.

[0080] Next, as shown in FIG. 8D, when the rotation angle ω of the scanning optical element 17 exceeds 45 degrees, the incident surface of the light ray LL changes from outer surface 17c1 to outer surface 17c2. At this time, the light ray LL is refracted at outer surface 17c2, but the refraction direction is different from that in the period up to FIG. 8C, and it is refracted in the direction shown in the figure (toward the -Y side). The exit surface of the light ray LL also changes from outer surface 17c3 to outer surface 17c4. However, because outer surfaces 17c2 and 17c4 are parallel to each other, the refraction angle of the light ray LL when it enters outer surface 17c3 and the refraction angle when it exits outer surface 17c4 cancel each other out, as in the period up to FIG. 8C. As a result, the light ray LL travels parallel to the illumination optical axis AX at a position displaced by a displacement amount d toward the -Y side from the illumination optical axis AX.

[0081] Next, as shown in Fig. 8E, when the rotation angle ω of the scanning optical element 17 becomes larger than that in Fig. 8D, the angle of incidence of the light ray LL becomes smaller, and the angle of refraction becomes smaller. Therefore, the displacement d of the light ray LL from the illumination optical axis AX becomes smaller than that in Fig. 8D. In this way, when the rotation angle ω is between 45 degrees and 90 degrees, the displacement d monotonically decreases as the rotation angle ω increases.

[0082] Next, as shown in FIG. 8F, when the rotation angle ω of the scanning optical element 17 reaches 90 degrees, the incident surface changes from the outer surface 17c1 in the initial state to the outer surface 17c2, but the behavior of the light ray LL becomes the same as in the initial state shown in FIG. 8A.

[0083] As described above, if the incident and exit surfaces of the scanning optical element 17 are parallel to each other, the direction of travel of the light ray LL does not change regardless of the rotation angle ω of the scanning optical element 17. Instead, the light ray LL translates parallel to the illumination optical axis AX over time. When the rotation angle ω is 0°, the displacement d of the light ray LL is 0. As the rotation angle ω ranges from 0° to 45°, the displacement d increases toward either the +Y or -Y direction. The moment the rotation angle ω exceeds 45°, the absolute value of the displacement d remains the same, but the direction of the displacement reverses. As the rotation angle ω ranges from 45° to 90°, the displacement d decreases. When the rotation angle ω reaches 90°, the displacement d becomes 0. After 90°, the above behavior is repeated. Therefore, when the scanning optical element 17 rotates once, the displacement d of the light ray LL repeats the above cycle four times. The displacement of the light ray LL can be appropriately set by adjusting the parameters of the scanning optical element 17, such as the refractive index and size.

[0084] Based on this configuration, the optical scanning device 20 scans the light beam LA emitted from the light source device 10 over a two-dimensional illuminated area Q on the illuminated surface, specifically, the image formation area of ​​the light modulation device 21.

[0085] Although the scanning optical element 17 has four outer surfaces, the number of outer surfaces does not necessarily have to be four; it is desirable that the number be 2×p (p: a natural number greater than or equal to 2). That is, it is desirable that the number of outer surfaces be an even number, for example, 6, 8, or the like. If the number of outer surfaces is an even number, each outer surface is parallel to the outer surface opposite it, and there are no outer surfaces that are not parallel. This reduces the generation of stray light in the scanning optical element 17, and improves light utilization efficiency.

[0086] Returning to FIG. 1 , the light modulation device 21 modulates the light beam LA emitted from the optical scanning device 20 in accordance with 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 include a color filter. If the liquid crystal panel includes a color filter, a projector 100 capable of color display can be realized. If the liquid crystal panel does not include a color filter, a projector 100 capable of monochrome display can be realized. The liquid crystal panel can be driven by any method, including twisted nematic (TN), vertical alignment (VA), and in-plane switching (IPS) methods, without any particular limitation.

[0087] The exit-side polarizing plate 22 is provided on the illumination 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 that is emitted from the light modulation device 21 toward the projection optical device 23. In the case of this embodiment, a laser diode is used in the light source unit 10a, so linearly polarized light is emitted from the light source device 10. Therefore, an entrance-side polarizing plate provided on the light entrance side of the light modulation device 21 is not necessary.

[0088] The projection optical device 23 is composed of a plurality of projection lenses, and projects the image light modulated by the light modulation device 21 onto a projection surface such as a screen in an enlarged scale. As a result, an image is displayed on a projection surface such as a screen.

[0089] In the projector 100 of this embodiment, at least one of the optical element 11 and the scanning optical element 17 may be made of quartz. In the optical element 11 and the scanning optical element 17, as the amount of light passing through the light-transmitting member increases, the amount of light absorbed by the light-transmitting member also increases, which may cause thermal distortion in the light-transmitting member. In this case, the polarization direction of the light L1 emitted from the light source unit 10a is disturbed, and linearly polarized light incident on the light-transmitting member becomes elliptically polarized light before being emitted from the light-transmitting member. As a result, the projector 100 loses the effect of achieving a predetermined contrast without an incident-side polarizer by using a laser diode for the light source unit 10a. In other words, even if the light source unit 10a uses a laser diode, an incident-side polarizer is required to align the polarization direction. Therefore, to achieve the above effect, it is desirable to use a glass material with a small Young's modulus and thermal expansion coefficient as a glass material with low thermal distortion, and quartz is a desirable example.

[0090] As described above, the light source device 10 of this embodiment includes the light source unit 10a that emits light L1, and the optical element 11 that is a stack of multiple transmissive optical elements 11a including the first transmissive optical element 41 and the second transmissive optical element 42. The first transmissive optical element 41 has a first incident surface 410 on which the first component L11 of the light L1 is incident and that forms a first angle θ1 with respect to a reference plane RP that is orthogonal to a light ray L1a that is a principal ray of the light L1, and a first exit surface 411 that emits the first component L11 of the light L1 that is incident from the first incident surface 410. The second transmissive optical element 42 has a second incident surface 420 onto which a second component L12 different from the first component L11 of the light L1 is incident and which forms a second angle θ2 with respect to the reference plane RP that is different from the first angle θ1, and a second exit surface 421 from which the second component L12 of the light L1 incident from the second incident surface 420 emerges. In the first transmissive optical element 41, the first incident surface 410 and the first exit surface 411 are parallel to each other, and in the second transmissive optical element 42, the second incident surface 420 and the second exit surface 421 are parallel to each other.

[0091] According to the light source device 10 of this embodiment, by using the optical element 11 in which the transmissive optical elements 11a are stacked, it is possible to generate an emitted light flux LA consisting of parallel light containing a plurality of components separated in the Z-axis direction. Therefore, according to the light source device 10 of this embodiment, it is possible to generate an emitted light flux LA consisting of parallel light having a desired shape with a simple configuration in which the optical element 11 made of a stack is used.

[0092] Furthermore, the light source device 10 of this embodiment can generate an emitted light beam LA that illuminates the illuminated area with uniform light intensity by optimizing the arrangement of each of the optical elements 41 to 47 that make up the optical element 11 according to the light intensity distribution of the light L1.

[0093] Furthermore, the optical scanning device 20 of this embodiment can two-dimensionally scan the belt-shaped emitted light beam LA, which is emitted from the light source device 10 and illuminates with uniform illuminance, on the image forming area of ​​the light modulation device 21 by using the scanning optical element 17. Therefore, the optical scanning device 20 can make illumination light with a uniform illuminance distribution incident on the image forming area of ​​the light modulation device 21.

[0094] Therefore, according to the projector 100 of this embodiment, by using the optical scanning device 20 to increase the uniformity of the illuminance distribution within the image forming area of ​​the optical modulation device 21, it is possible to suppress the decrease in brightness and contrast and the occurrence of color unevenness in the optical modulation device 21, thereby realizing a projector with excellent display quality.

[0095] In the optical element 11 of this embodiment, an example has been given in which the positions of the optical elements 41 to 47 are arranged in a state where they are twisted by 90 degrees at both ends in the stacking direction, but the optical elements 41 to 47 may also be arranged in a state where they are twisted by more than 90 degrees at both ends. In addition, when the cross-sectional shape of the multiple transmissive optical elements that make up the optical element is a regular n-gon (n is an even number greater than or equal to 2), it is desirable to arrange the optical element so that the position of each transmissive optical element is twisted by 360 / n degrees or more within the luminous flux width of the incident light. With this configuration, each component separated by the optical element can be moved to an appropriate position in the Z-axis direction, which is perpendicular to the stacking direction of each transmissive optical element, thereby making it possible to effectively form a line of light having a highly uniform illuminance distribution in the Z-axis direction.

[0096] (Second embodiment) A second embodiment of the present invention will be described below with reference to FIG. The projector of this embodiment is a three-panel projector that uses three liquid crystal panels as a light modulation device, and differs from the first embodiment, which is a single-panel projector that uses one liquid crystal panel. Note that the same reference numerals are used for components that are common to the first embodiment, and detailed descriptions will be omitted.

[0097] FIG. 9 is a plan view showing a schematic configuration of a projector 200 of this embodiment. As shown in FIG. 9, the projector 200 of this embodiment includes an optical scanning device 220, a magnifying optical system 202, a color separation optical system 203, a light modulation device 30, an image light combining element 24, and a projection optical device 23.

[0098] The optical scanning device 220 of this embodiment includes a light source device 210 and a scanning optical element 17. The light source device 210 includes a first light source unit 101, a second light source unit 102, a third light source unit 103, a light combining optical system 104, and an optical element 11.

[0099] The first light source unit 101 is disposed such that the optical axis AX1 of the first light source unit 101 is perpendicular to the optical axis AX2 of the second light source unit 102. The third light source unit 103 is disposed such that the optical axis AX3 of the third light source unit 103 is perpendicular to the optical axis AX2 of the second light source unit 102. The first light source unit 101 emits blue light LB toward the -Z side. The third light source unit 103 emits red light LR toward the -Z side. The second light source unit 102 emits green light LG toward the +X side. In this example, the first light source unit 101 is disposed closer to the second light source unit 102, and the third light source unit 103 is disposed farther from the second light source unit 102, but the opposite may also be true.

[0100] The first light source unit 101 has a first light-emitting element 25 and a substrate 29. The first light-emitting element 25 is composed of a laser diode that emits light in a first wavelength band. Therefore, the light emitted from the first light-emitting element 25 is linearly polarized light with coherence, and is laser light with a narrow beam width and high parallelism. The first wavelength band is, for example, a blue wavelength band of 450 nm±5 nm. That is, the first light-emitting element 25 emits blue light LB as the first light.

[0101] The second light source unit 102 has a second light-emitting element 26 and a substrate 29. The second light-emitting element 26 is composed of a laser diode that emits light in a second wavelength band different from the first wavelength band. The light emitted from the second light-emitting element 26 is linearly polarized light with coherence, and is laser light with a narrow beam width and high parallelism. The second wavelength band is, for example, a green wavelength band of 530 nm±5 nm. That is, the second light-emitting element 26 emits green light LG as the second light.

[0102] The third light source unit 103 has a third light-emitting element 27 and a substrate 29. The third light-emitting element 27 is composed of a laser diode that emits light in a third wavelength band different from the first wavelength band and the second wavelength band. The light emitted from the third light-emitting element 27 is coherent linearly polarized light, and is laser light with a narrow beam width and high parallelism. The third wavelength band is, for example, a red wavelength band of 650 nm±5 nm. That is, the third light-emitting element 27 emits red light LR as the third light.

[0103] The light combining optical system 104 includes a first light combining element 105 and a second light combining element 106. The first light combining element 105 is provided at a position where the optical axes AX1 and AX2 intersect. The first light combining element 105 is composed of a dichroic mirror that transmits the green light LG and reflects the blue light LB. The second light combining element 106 is provided at a position where the optical axes AX2 and AX3 intersect. The second light combining element 106 is composed of a dichroic mirror that transmits the green light LG and the blue light LB and reflects the red light LR. The light combining optical system 104 combines the blue light LB emitted from the first light source unit 101, the green light LG emitted from the second light source unit 102, and the red light LR emitted from the third light source unit 103 to generate white illumination light WL. As a result, the light source device 210 emits illumination light WL. The illumination light WL is incident on the optical element 11 without being separated by wavelength band.

[0104] The light source device 210 of this embodiment can also convert the illumination light WL into a strip-like illumination light WL1 made of parallel light. The optical scanning device 220 of this embodiment can also improve the uniformity of the illuminance distribution when the illumination light WL1 is scanned within a two-dimensional illumination area on the illumination surface, i.e., on each of the light modulation elements 30B, 30G, and 30R.

[0105] The illumination light WL1 is incident on the magnifying optical system 202. The magnifying optical system 202 includes, for example, a concave lens 2a and a convex lens 2b. The magnifying optical system 202 magnifies the beam diameter of the illumination light WL1 emitted from the optical scanning device 220.

[0106] The illumination light WL 1 that has passed through the magnifying optical system 202 enters the color separating optical system 203 . The color separation optical system 203 separates the illumination light WL emitted from the optical scanning device 220 into red light LR, green light LG, and blue light LB, and guides them to the light modulation elements of the light modulation device 30.

[0107] The light modulation device 30 of this embodiment includes a first light modulation element 30B, a second light modulation element 30G, a third light modulation element 30R, and half-wave plates 33B and 33R.

[0108] The color separation optical system 3 includes a first dichroic mirror 7a, a second dichroic mirror 7b, a first total reflection mirror 8a, a second total reflection mirror 8b, and a third total reflection mirror 8c.

[0109] The first dichroic mirror 7a separates the illumination light WL1 from the optical scanning device 220 into red light LR and light containing green light LG and blue light LB. The first dichroic mirror 7a transmits the blue light LB and reflects the light containing green light LG and red light LR. On the other hand, the second dichroic mirror 7b reflects the green light LG and transmits the red light LR. In this way, the second dichroic mirror 7b separates the light containing green light LG and red light LR into green light LG and red light LR.

[0110] The first total reflection mirror 8a is disposed in the optical path of the blue light LB and reflects the blue light LB that has passed through the first dichroic mirror 7a toward the first light modulation element 30B. Meanwhile, the second total reflection mirror 8b and the third total reflection mirror 8c are disposed in the optical path of the blue light LB and guide the red light LR that has passed through the second dichroic mirror 7b toward the third light modulation element 30R. The green light LG is reflected from the second dichroic mirror 7b toward the second light modulation element 30G.

[0111] The first light modulation element 30B has a light modulation panel 31B and an exit-side polarizing plate 32B. The second light modulation element 30G has a light modulation panel 31G and an exit-side polarizing plate 32G. The third light modulation element 30R has a light modulation panel 31R and an exit-side polarizing plate 32R.

[0112] A transmissive liquid crystal panel is used for each of the light modulation panels 31B, 31G, and 31R. The driving method for the liquid crystal panel is not particularly limited, and may be a twisted nematic (TN) method, a vertically aligned (VA) method, an in-plane switching (IPS) method, or the like. The driving of each of the light modulation panels 31B, 31G, and 31R of the light modulation elements 30B, 30G, and 30R is controlled by a control device electrically connected thereto.

[0113] Each of the exit-side polarizing plates 32B, 32G, and 32R transmits linearly polarized light in a specific direction. In this embodiment, since each of the light source units 101, 102, and 103 of the optical scanning device 220 emits laser light as blue light LB, green light LG, and red light LR, the polarizing plate on the light entrance side of each of the optical modulation elements 30B, 30G, and 30R can be omitted.

[0114] The optical scanning device 220 superimposes the blue light LB in time by two-dimensionally scanning the image formation area of ​​the first light modulation element 30B. The first light modulation element 30B modulates the blue light LB based on blue image information to generate blue image light B. The optical scanning device 220 superimposes the green light LG in time by two-dimensionally scanning the image formation area of ​​the second light modulation element 30G. The second light modulation element 30G modulates the green light LG based on green image information to generate green image light G. The optical scanning device 220 superimposes the red light LR in time by two-dimensionally scanning the image forming area of ​​the third light modulation element 30R. The third light modulation element 30R modulates the red light LR based on red image information to generate red image light R.

[0115] The image light combining element 24 combines the image light of each color B, G, R emitted from the first light modulation element 30B, the second light modulation element 30G, and the third light modulation element 30R to generate full-color image light, and emits the combined full-color image light toward the projection optical device 23. The image light combining element 24 may be, for example, a cross dichroic prism.

[0116] Half-wave plates 33B and 33R are provided between the first light modulation element 30B and the image light combiner 24, and between the third light modulation element 30R and the image light combiner 24, respectively. The half-wave plates 33B and 33R impart a phase difference of half a wavelength to the incident color light and rotate the polarization direction of the linearly polarized light by 90 degrees. This makes it possible to make the polarization direction of the green image light G incident on the image light combiner 24 different from the polarization directions of the blue image light B and red image light R incident on the image light combiner 24. This configuration can improve the light utilization efficiency of the image light combiner 24. The projection optical device 23 enlarges and projects the image light emitted from the image light synthesizing element 24 onto a projection surface such as a screen, thereby displaying an image on the projection surface.

[0117] In the projector 200 of this embodiment, by increasing the uniformity of the illuminance distribution within the image forming area of ​​each light modulation element 30B, 30G, 30R, it is possible to suppress the decrease in brightness and contrast and the occurrence of color unevenness in each light modulation element 30B, 30G, 30R, thereby realizing a three-plate projector with excellent display quality.

[0118] (Third embodiment) A third embodiment of the present invention will be described below with reference to FIG. The projector of this embodiment is a three-panel projector that uses three liquid crystal panels as a light modulation device, and the configuration of the light source device, etc. is different from that of the second embodiment. Note that the same reference numerals are used for components that are common to the first and second embodiments, and detailed descriptions thereof will be omitted.

[0119] FIG. 10 is a plan view showing a schematic configuration of a projector 300 of this embodiment. 10, the projector 300 of this embodiment includes an optical scanning device 320, a first reflecting mirror 141, a second reflecting mirror 142, an optical modulation device 30, an image light combining element 24, and a projection optical device 23. The configuration of the projector 300 other than the light source device 310 is the same as that of the first embodiment.

[0120] The optical scanning device 320 of this embodiment includes a light source device 310, a first scanning optical element 121, a second scanning optical element 122, and a third scanning optical element 123. The light source device 310 includes a first light source unit 101, a second light source unit 102, a third light source unit 103, an optical element 11, a first wavelength-selective reflecting element 71, and a second wavelength-selective reflecting element 72.

[0121] In the light source device 310 of this embodiment, as in the second embodiment, each of the light source units 101, 102, and 103 includes one light-emitting element 25, 26, and 27. The first light source unit 101 emits blue light LB toward the -Z side. The second light source unit 102 emits green light LG toward the +X side. The third light source unit 103 emits red light LR toward the +Z side. That is, the first light source unit 101 and the third light source unit 103 are disposed opposite each other and emit light in opposite directions. Furthermore, the optical axis AX1 and the optical axis AX3 are located on the same axis and are perpendicular to the optical axis AX2.

[0122] The first wavelength-selective reflecting element 71 is provided on the optical path of the red light LR emitted from the third light source unit 103 between the third light source unit 103 and the optical element 11. The first wavelength-selective reflecting element 71 is composed of a dichroic mirror that reflects blue light and transmits red light.

[0123] The second wavelength-selective reflecting element 72 is provided on the optical path of the blue light LB emitted from the second light source unit 102 between the second light source unit 102 and the optical element 11. The second wavelength-selective reflecting element 72 is composed of a dichroic mirror that transmits blue light and reflects red light.

[0124] In this embodiment, multiple colored lights having different wavelength bands are incident on the optical element 11. In this case, it is desirable to use a glass material with small wavelength dispersion, i.e., a glass material with a large Abbe number, as the glass material for the light-transmitting member. Green light LG, blue light LB, and red light LR are emitted from the optical element 11.

[0125] The first scanning optical element 121, the second scanning optical element 122, and the third scanning optical element 123 have the same configuration as the scanning optical element 17 of the first embodiment. The first scanning optical element 121 is made of a rotatably supported light-transmitting member. The first scanning optical element 121 is rotatable about a first rotation axis C1 extending along the Z-axis direction. The shape and size of the first scanning optical element 121 are the same as the shape and size of the scanning optical element 17. The first scanning optical element 121 has a front surface 121a and a back surface 121b that intersect with the first rotation axis C1, and four side surfaces 121c that are perpendicular to the front surface 121a and the back surface 121b. That is, the shape of the first scanning optical element 121 is a regular quadrangular prism with six flat surfaces.

[0126] The second scanning optical element 122 is made of a rotatably supported light-transmitting member. The second scanning optical element 122 is rotatable about a second rotation axis C2 extending along the Z-axis direction. The shape and size of the second scanning optical element 122 are the same as the shape and size of the first scanning optical element 121. The second scanning optical element 122 has a front surface 122a and a back surface 122b that intersect with the second rotation axis C2, and four side surfaces 122c that are perpendicular to the front surface 122a and the back surface 122b. That is, the shape of the second scanning optical element 122 is a regular quadrangular prism with six flat surfaces.

[0127] The third scanning optical element 123 is made of a rotatably supported light-transmitting member. The third scanning optical element 123 is rotatable about a third rotation axis C3 extending along the Z-axis direction. The shape and size of the third scanning optical element 123 are the same as the shapes and sizes of the first scanning optical element 121 and the second scanning optical element 122. The third scanning optical element 123 has a front surface 123a and a back surface 123b that intersect with the third rotation axis C3, and four side surfaces 123c that are perpendicular to the front surface 123a and the back surface 123b. That is, the shape of the third scanning optical element 123 is a regular quadrangular prism with six flat surfaces.

[0128] The green light LG emitted from the optical element 11 is incident on the second scanning optical element 122. The blue light LB emitted from the optical element 11 and reflected by the first wavelength selective reflecting element 71 is incident on the third scanning optical element 123. The red light LR emitted from the optical element 11 and reflected by the second wavelength selective reflecting element 72 is incident on the first scanning optical element 121.

[0129] According to the light source device 310 of this embodiment, the optical element 11 can convert the red light LR, green light LG, and blue light LB into strip-shaped red illumination light LR1, green illumination light LG1, and blue illumination light LB1, each consisting of parallel light.

[0130] In the first scanning optical element 121, the side surface onto which the blue illumination light LB1 emitted from the optical element 11 is incident is referred to as the fourth entrance surface. The side surface from which the blue illumination light LB1 incident from the fourth entrance surface is emitted is referred to as the fourth exit surface. The fourth entrance surface and the fourth exit surface change over time and are either of two parallel fourth side surfaces among the four side surfaces 121c. In other words, the fourth entrance surface and the fourth exit surface are parallel to each other.

[0131] In the second scanning optical element 122, the side surface onto which the green illumination light LG1 emitted from the optical element 11 is incident is referred to as the fifth entrance surface. The side surface from which the green illumination light LG1 incident from the fifth entrance surface is emitted is referred to as the fifth exit surface. The fifth entrance surface and the fifth exit surface change over time and are either of two parallel fifth side surfaces among the four side surfaces 122c. In other words, the fifth entrance surface and the fifth exit surface are parallel to each other.

[0132] In the third scanning optical element 123, the side surface onto which the red illumination light LR1 emitted from the optical element 11 is incident is referred to as the sixth entrance surface. The side surface from which the red illumination light LR1 incident from the sixth entrance surface is emitted is referred to as the sixth exit surface. The sixth entrance surface and the sixth exit surface change over time and are either of two sixth side surfaces among the four side surfaces 123c that are parallel to each other. In other words, the sixth entrance surface and the sixth exit surface are parallel to each other.

[0133] The first rotation axis C1 of the first scanning optical element 121, the second rotation axis C2 of the second scanning optical element 122, and the third rotation axis C3 of the third scanning optical element 123 are located on the same axis. In this embodiment, the first scanning optical element 121, the second scanning optical element 122, and the third scanning optical element 123 are connected to the rotation drive unit 16 via a common shaft. This configuration allows for a reduction in the number of rotation drive units and a simplification of the device configuration compared to when a rotation drive unit is provided for each transmitting optical element. Furthermore, there is no need to synchronize conditions such as the rotation speed and phase of the three optical elements 121, 122, and 123, making rotation control easier. Furthermore, it is possible to reduce scroll noise that occurs due to missynchronization of rotation.

[0134] 10, the optical elements 121, 122, and 123 are each made of a separate light-transmitting member. However, instead of this configuration, the optical elements 121, 122, and 123 may be made of a single light-transmitting member. This configuration eliminates gaps between adjacent transmissive optical elements, thereby enabling the transmissive optical elements to be made smaller. Furthermore, the aforementioned effects of facilitating rotation control and reducing scroll noise can be achieved.

[0135] The first reflecting mirror 141 reflects the blue illumination light LB1 emitted from the first scanning optical element 121 toward the first light modulation element 30B. In this way, the first reflecting mirror 141 bends the optical path of the blue illumination light LB1 emitted from the first scanning optical element 121 from the +X direction to the -Z direction.

[0136] The second reflecting mirror 142 reflects the red illumination light LR1 emitted from the third scanning optical element 123 toward the third light modulation element 30R. In this way, the second reflecting mirror 142 bends the optical path of the red illumination light LR1 emitted from the third scanning optical element 123 from the +X direction to the +Z direction.

[0137] In this way, the light source device 310 of this embodiment can also generate the respective colored illumination lights LB1, LG1, LR1 in the form of strips of parallel light. Also, the optical scanning device 320 of this embodiment can improve the uniformity of the illuminance distribution when the respective colored illumination lights LB1, LG1, LR1 are scanned within a two-dimensional illuminated area on the illuminated surface, i.e., on the respective light modulation elements 30B, 30G, 30R. Therefore, according to the projector 300 of this embodiment, by increasing the uniformity of the illuminance distribution within the image forming area of ​​each light modulation element 30B, 30G, 30R, it is possible to obtain the same effect as in the second embodiment, such as suppressing a decrease in brightness and contrast and the occurrence of color unevenness in each light modulation element 30B, 30G, 30R, and it is possible to realize a projector 300 capable of displaying color images.

[0138] 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.

[0139] In addition, the specific descriptions of the shape, number, arrangement, materials, etc. of each component of the light source device and the projector are not limited to the above-described embodiment and can be modified as appropriate. Furthermore, in the above-described embodiment, an example was shown in which the light source device according to the present invention is mounted on a projector using a liquid crystal panel, but this is not limiting. The light source device according to the present invention may also be applied to a projector using a digital micromirror device as a light modulation device.

[0140] A summary of this disclosure is provided below. (Appendix 1) a light source unit that emits light; an optical element in which a plurality of transmissive optical elements including a first transmissive optical element and a second transmissive optical element are stacked; Equipped with The first transmissive optical element is a first incident surface onto which the first component of the light is incident and which forms a first angle with respect to a reference plane orthogonal to a chief ray of the light; a first exit surface that exits the first component of the light incident from the first entrance surface, The second transmissive optical element is a second incident surface onto which a second component of the light different from the first component is incident and which forms a second angle with respect to the reference surface different from the first angle; a second exit surface that exits the second component of the light incident from the second entrance surface, In the first transmissive optical element, the first entrance surface and the first exit surface are parallel to each other, In the second transmissive optical element, the second entrance surface and the second exit surface are parallel to each other. Light source device.

[0141] According to the light source device having this configuration, the optical element can emit light emitted from the light source unit as a luminous flux having a shape elongated in a direction intersecting the stacking direction and including a first component and a second component consisting of parallel light. With this light source device, an emitted luminous flux consisting of parallel light of a desired shape can be generated with a simple configuration. Furthermore, by adjusting the emission positions of the first component and the second component, the uniformity of the illuminance distribution of the emitted luminous flux LA can be improved.

[0142] (Appendix 2) the first transmissive optical element has 2×m (m: a natural number equal to or greater than 2) first side surfaces that intersect with first and second surfaces that are orthogonal to a stacking direction of the plurality of transmissive optical elements and are in contact with the first and second surfaces, the second transmissive optical element has 2×n (n: a natural number equal to or greater than 2) second side surfaces that intersect with third and fourth surfaces that are orthogonal to the stacking direction and are in contact with the third and fourth surfaces, the first entrance surface and the first exit surface are two of the 2×m first side surfaces that are parallel to each other, The second entrance surface and the second exit surface are two second side surfaces parallel to each other among the 2×n second side surfaces. 10. The light source device of claim 1.

[0143] With this configuration, since the number of first and second side surfaces is an even number, all of the first and second side surfaces are parallel to the first and second side surfaces facing them, respectively, and no first and second side surfaces are non-parallel. As a result, the generation of stray light in the first and second transmissive optical elements is reduced, and light utilization efficiency can be improved.

[0144] (Appendix 3) The size of the first transmissive optical element is equal to the size of the second transmissive optical element. 10. The light source device according to claim 1 or 2.

[0145] According to this configuration, the components of each optical element can be standardized, which improves the ease of assembling the optical elements and reduces costs.

[0146] (Appendix 4) the plurality of transmissive optical elements constituting the optical element further include a third transmissive optical element, The third transmissive optical element is a third incident surface onto which a third component of the light, which is different from the first component and the second component, is incident and which forms a third angle with respect to the reference plane, which is different from the first angle and the second angle; a third exit surface that exits the third component of the light incident from the third entrance surface, In the third transmissive optical element, the third entrance surface and the third exit surface are parallel to each other, The dimension of the long side direction of the light emitted from the optical element is different from the dimension of the long side direction of the light at the time of incidence on the optical element. 4. A light source device according to any one of claims 1 to 3.

[0147] According to this configuration, by generating parallel light including the first component, the second component, and the third component, it is possible to generate light having a different elongated shape from when it is incident on the optical element.

[0148] (Appendix 5) the first transmissive optical element, the second transmissive optical element, and the third transmissive optical element are arranged in this order in a stacking direction of the plurality of transmissive optical elements constituting the optical element, an angle formed by the first incident surface of the first transmissive optical element and the second incident surface of the second transmissive optical element is equal to an angle formed by the second incident surface of the second transmissive optical element and the third incident surface of the third transmissive optical element; 5. The light source device according to claim 4.

[0149] According to this configuration, the first transmissive optical element, the second transmissive optical element, and the third transmissive optical element are arranged in a state rotated by an equal angle, so that the displacement amount of the light transmitted through each transmissive optical element can be changed at a constant rate, which makes it easier to improve the uniformity of the illuminance distribution of the light transmitted through the optical elements.

[0150] (Appendix 6) In the stacking direction of the plurality of transmissive optical elements, a center of the first transmissive optical element overlaps with a center of the second transmissive optical element. 6. A light source device according to any one of claims 1 to 5.

[0151] According to this configuration, the optical elements are aligned with each other with high precision, which makes it easy to align the optical elements constituting the optical system with the illumination optical axis.

[0152] (Appendix 7) In the optical element, the refractive index of the first transmissive optical element is equal to the refractive index of the second transmissive optical element. 7. A light source device according to any one of claims 1 to 6.

[0153] According to this configuration, the refraction angles of the light transmitted through each optical element can be easily aligned, which makes it easy to adjust the optical path of the light transmitted through the optical elements.

[0154] (Appendix 8) a light source device according to any one of Supplementary Note 1 to Supplementary Note 7; a scanning optical element that rotates about an axis that intersects with the stacking direction of the plurality of transmissive optical elements and scans the light emitted from the light source device, Optical scanning device.

[0155] According to the optical scanning device having this configuration, the scanning optical element can two-dimensionally scan the illuminated area with parallel light of a predetermined shape emitted from the light source device, thereby allowing the optical scanning device to input light with a uniform illuminance distribution to the optical modulation device.

[0156] (Appendix 9) an optical scanning device according to Supplementary Note 8; a light modulation device that modulates the light emitted from the optical scanning device based on image information; a projection optical device that projects the light emitted from the light modulation device, projector.

[0157] With a projector of this configuration, the optical scanning device increases the uniformity of the illuminance distribution in the light modulation device, thereby suppressing the reduction in brightness and contrast and the occurrence of color unevenness in the light modulation device, thereby achieving a projector with excellent display quality.

[0158] (Appendix 10) a first transmissive optical element made of a light-transmitting member, the first transmissive optical element having a first incident surface on which a first component of light emitted from a light source unit is incident, a first exit surface from which the first component of the light incident from the first incident surface exits, and a first surface and a second surface intersecting the first incident surface and the first exit surface; a second transmissive optical element made of a light-transmitting member, the second transmissive optical element having a second incident surface onto which a second component of the light emitted from the light source unit is incident, a second exit surface from which the second component of the light incident from the second incident surface exits, and a third surface and a fourth surface intersecting the second incident surface and the second exit surface; a third transmissive optical element made of a light-transmitting member, the third transmissive optical element having a third entrance surface on which a third component of the light emitted from the light source unit is incident, a third exit surface from which the third component of the light incident from the third entrance surface exits, and fifth and sixth surfaces intersecting the third entrance surface and the third exit surface, the method comprising: a holding step of opposing the second surface of the first transmissive optical element to the third surface of the second transmissive optical element so that the first incident surface and the second incident surface are non-parallel to each other, and abutting the fourth surface of the second transmissive optical element to the fifth surface of the third transmissive optical element so that the second incident surface and the third incident surface are non-parallel to each other; a bonding step of bonding the first transmissive optical element, the second transmissive optical element, and the third transmissive optical element to one another, A method for manufacturing an optical element.

[0159] According to the manufacturing method of the optical element having this configuration, an optical element in which the first transmissive optical element, the second transmissive optical element, and the third transmissive optical element are stacked can be manufactured simply and with high precision.

[0160] (Appendix 11) In the holding step, an ultraviolet curing adhesive is placed between the second surface of the first transmitting optical element and the third surface of the second transmitting optical element, and between the fourth surface of the second transmitting optical element and the fifth surface of the third transmitting optical element. A method for manufacturing an optical element according to claim 10.

[0161] According to this configuration, the first transmissive optical element, the second transmissive optical element, and the third transmissive optical element can be bonded together by a simple process such as irradiation with ultraviolet light.

[0162] (Appendix 12) the bonding step includes a holding step of holding the first transmissive optical element, the second transmissive optical element, and the third transmissive optical element at positions that do not interfere with the optical axis of a stack of the first transmissive optical element, the second transmissive optical element, and the third transmissive optical element, respectively. A method for manufacturing an optical element according to claim 11.

[0163] This configuration allows each optical element to be held without interfering with the optical axis of the laminate, thereby preventing problems such as the holding member for holding the optical element interfering with the confirmation light for confirming the quality of the optical element.

[0164] (Appendix 13) the bonding step includes a confirmation step of irradiating confirmation light of a wavelength band that does not harden the adhesive onto the laminate held in the holding step, and confirming an illuminance distribution of the confirmation light emitted from the laminate. A method for manufacturing an optical element according to claim 12.

[0165] With this configuration, the confirmation light is not blocked by the holding member that holds the optical element, which allows for good quality inspection of the laminate using the confirmation light, thereby enabling the production of high-quality optical elements.

[0166] (Appendix 14) the bonding step includes an adjustment step of adjusting positions of the first transmissive optical element, the second transmissive optical element, and the third transmissive optical element constituting the laminate based on a result of the confirmation step, and then performing the confirmation step using the laminate after the position adjustment. A method for manufacturing an optical element according to claim 13.

[0167] According to this configuration, the quality of the optical element can be further improved by repeating the adjustment step and the checking step.

[0168] (Appendix 15) the bonding step includes a curing step of irradiating ultraviolet light onto the laminate that satisfies the reference value when the illuminance distribution of the confirmation light satisfies the reference value in the adjusting step. A method for manufacturing an optical element according to claim 14.

[0169] This configuration allows the bonding process to be easily carried out by curing the adhesive with ultraviolet light. Furthermore, since the adhesive of the laminated body that satisfies the standard value is cured, the occurrence of manufacturing defects in the optical element can be minimized. [Explanation of symbols]

[0170] 21,30...light modulation device, 10,210,310...light source device, 10a...light source section, 11...optical element, 11a...transmissive optical element, 12...incident surface, 13...exit surface, 17...scanning optical element, 20,220,320...optical scanning device, 23...projection optical device, 41...first transmissive optical element, 41a...first surface, 41b...second surface, 42...second transmissive optical element, 42a...third surface, 42b...fourth surface, 43...third transmissive optical element, 43a...fifth surface, 43b...sixth surface, 100,200, 300...Projector, 410...First entrance surface, 411...First exit surface, 41c1, 41c2, 41c3, 41c4...First side surface, 420...Second entrance surface, 421...Second exit surface, 42c1, 42c2, 42c3, 42c4...Second Side surface, 430...Third entrance surface, 431...Third exit surface, L1...Light, L11...First component, L12...Second component, L13...Third component, L1a...Light ray (principal ray of light), RP...Reference plane, θ1...First angle, θ2...Second angle, θ3...Third angle.

Claims

1. a light source unit that emits light; an optical element in which a plurality of transmissive optical elements including a first transmissive optical element and a second transmissive optical element are stacked; Equipped with The first transmissive optical element is a first incident surface onto which the first component of the light is incident and which forms a first angle with respect to a reference plane orthogonal to a chief ray of the light; a first exit surface that exits the first component of the light incident from the first entrance surface, The second transmissive optical element is a second incident surface onto which a second component of the light different from the first component is incident and which forms a second angle with respect to the reference plane different from the first angle; a second exit surface that exits the second component of the light incident from the second entrance surface, In the first transmissive optical element, the first entrance surface and the first exit surface are parallel to each other, In the second transmissive optical element, the second entrance surface and the second exit surface are parallel to each other. Light source device.

2. the first transmissive optical element has 2×m (m: a natural number equal to or greater than 2) first side surfaces that intersect with first and second surfaces that are orthogonal to a stacking direction of the plurality of transmissive optical elements and are in contact with the first and second surfaces, the second transmissive optical element has 2×n (n: a natural number equal to or greater than 2) second side surfaces that intersect with third and fourth surfaces that are orthogonal to the stacking direction and are in contact with the third and fourth surfaces, the first entrance surface and the first exit surface are two of the 2×m first side surfaces that are parallel to each other, The second entrance surface and the second exit surface are two second side surfaces parallel to each other among the 2×n second side surfaces. The light source device according to claim 1 .

3. The size of the first transmissive optical element is equal to the size of the second transmissive optical element. The light source device according to claim 1 .

4. the plurality of transmissive optical elements constituting the optical element further include a third transmissive optical element, The third transmissive optical element is a third incident surface onto which a third component of the light, which is different from the first component and the second component, is incident and which forms a third angle with respect to the reference plane, which is different from the first angle and the second angle; a third exit surface that exits the third component of the light incident from the third entrance surface, In the third transmissive optical element, the third entrance surface and the third exit surface are parallel to each other, The dimension of the long side direction of the light emitted from the optical element is different from the dimension of the long side direction of the light at the time of incidence on the optical element. The light source device according to claim 1 .

5. the first transmissive optical element, the second transmissive optical element, and the third transmissive optical element are arranged in this order in a stacking direction of the plurality of transmissive optical elements constituting the optical element, an angle formed by the first incident surface of the first transmissive optical element and the second incident surface of the second transmissive optical element is equal to an angle formed by the second incident surface of the second transmissive optical element and the third incident surface of the third transmissive optical element; The light source device according to claim 4 .

6. a center of the first transmissive optical element overlaps a center of the second transmissive optical element in a stacking direction of the plurality of transmissive optical elements; The light source device according to claim 1 .

7. In the optical element, the refractive index of the first transmissive optical element is equal to the refractive index of the second transmissive optical element. The light source device according to claim 1 .

8. The light source device according to any one of claims 1 to 7, a scanning optical element that rotates about an axis that intersects with the stacking direction of the plurality of transmissive optical elements and scans the light emitted from the light source device, Optical scanning device.

9. The optical scanning device according to claim 8 ; a light modulation device that modulates the light emitted from the optical scanning device based on image information; a projection optical device that projects the light emitted from the light modulation device, projector.

10. a first transmissive optical element made of a light-transmitting member, the first transmissive optical element having a first incident surface on which a first component of light emitted from a light source unit is incident, a first exit surface from which the first component of the light incident from the first incident surface exits, and a first surface and a second surface intersecting the first incident surface and the first exit surface; a second transmissive optical element made of a light-transmitting member, the second transmissive optical element having a second incident surface on which a second component of the light emitted from the light source unit is incident, a second exit surface from which the second component of the light incident from the second incident surface exits, and a third surface and a fourth surface intersecting the second incident surface and the second exit surface; a third transmissive optical element made of a light-transmitting member, the third transmissive optical element having a third incident surface on which a third component of the light emitted from the light source unit is incident, a third exit surface from which the third component of the light incident from the third incident surface exits, and fifth and sixth surfaces intersecting the third incident surface and the third exit surface, a holding step of opposing the second surface of the first transmissive optical element to the third surface of the second transmissive optical element so that the first entrance surface and the second entrance surface are non-parallel to each other, and abutting the fourth surface of the second transmissive optical element to the fifth surface of the third transmissive optical element so that the second entrance surface and the third entrance surface are non-parallel to each other; a bonding step of bonding the first transmissive optical element, the second transmissive optical element, and the third transmissive optical element to one another, A method for manufacturing an optical element.

11. In the holding step, an ultraviolet curing adhesive is disposed between the second surface of the first transmissive optical element and the third surface of the second transmissive optical element, and between the fourth surface of the second transmissive optical element and the fifth surface of the third transmissive optical element. The method for manufacturing an optical element according to claim 10 .

12. the bonding step includes a holding step of holding the first transmissive optical element, the second transmissive optical element, and the third transmissive optical element at positions that do not interfere with an optical axis of a stack including the first transmissive optical element, the second transmissive optical element, and the third transmissive optical element, respectively. The method for manufacturing an optical element according to claim 11 .

13. the bonding step includes a confirmation step of irradiating the laminate held in the holding step with confirmation light of a wavelength band that does not harden the adhesive, and confirming an illuminance distribution of the confirmation light emitted from the laminate. The method for manufacturing an optical element according to claim 12 .

14. the bonding step includes an adjustment step of adjusting positions of the first transmissive optical element, the second transmissive optical element, and the third transmissive optical element constituting the laminate based on a result of the confirmation step, and then performing the confirmation step using the laminate after the position adjustment. The method for manufacturing an optical element according to claim 13 .

15. the bonding step includes a curing step of irradiating ultraviolet light onto the laminate that satisfies the reference value when the illuminance distribution of the confirmation light satisfies the reference value in the adjusting step. The method for manufacturing an optical element according to claim 14 .

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