Light source device and projector

Abstract

To provide a light source device that can emit light with high parallelism, and a projector.SOLUTION: A light source device comprises: a light source portion that emits first light; a color wheel on which the first light is incident; and a first transmissive optical element having a first incidence surface on which light is incident from the color wheel and a first emission surface from which the light is emitted. The first transmissive optical element has the first incidence surface and the first emission surface parallel to each other and rotates about a first rotation axis extending along a second direction crossing a first direction, which is a light incident direction. The color wheel includes a first region from which the first light incident from the light source portion is emitted and a second region from which second light is emitted, and rotates about a second rotation axis extending along the second direction. The first timing, when the first light is incident on the first region, synchronizes the second timing, when the first light is incident on the first incidence surface, and the third timing, when the first light is incident on the second region, synchronizes the fourth timing, when the second light is incident on the first incidence surface.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Conventionally, there is a projector that illuminates a light modulation device such as a liquid crystal panel by scanning light emitted from a light-emitting element over time on the light modulation device. Patent Document 1 listed below discloses a projector that includes a light source device including a light source lamp, a liquid crystal light valve, a polygon mirror provided between the light source device and the liquid crystal light valve, and a projection lens. 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] However, when a polygon mirror is used to scan light, as in the projector of Patent Document 1, even if perfectly parallel light is incident on the polygon mirror, the parallelism of the light is lost due to the polygon mirror. In other words, because the polygon mirror reflects light while rotating, the angle of incidence of the light on the reflective surface of the polygon mirror changes over time, and the parallel light incident on the polygon mirror becomes light with a predetermined divergence angle and illuminates the image formation area of ​​the liquid crystal light valve. As a result, various problems related to the image quality of the projector may occur, such as a decrease in brightness and contrast in the liquid crystal light valve, the occurrence of color unevenness, and light loss in the projection lens. [Means for solving the problem]

[0005] In order to solve the above problems, according to a first aspect of the present invention, there is provided a light source device.

[0006] According to a second aspect of the present invention, there is provided a projector comprising the light source device of the first aspect, an optical modulation device that modulates light emitted from the light source device in accordance with image information, and a projection optical device that projects the light modulated by the optical modulation device. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view showing a schematic configuration of a projector according to a first embodiment. [Figure 2A] 10A and 10B are diagrams illustrating the behavior of illumination light when the first transmissive optical element rotates. [Figure 2B] 2B is a diagram illustrating the behavior of illumination light following FIG. 2A. FIG. [Figure 2C] FIG. 2C is a diagram illustrating the behavior of illumination light following FIG. 2B. [Figure 2D] 2C, and is a diagram illustrating the behavior of illumination light. FIG. [Figure 2E] FIG. 2B is a diagram illustrating the behavior of illumination light following FIG. 2D. [Figure 2F] FIG. 2C is a diagram illustrating the behavior of illumination light, following FIG. 2E. [Figure 3] FIG. 2 is a plan view of a color wheel. [Figure 4] FIG. 10 is a diagram showing how illumination light scans on a light modulation device. [Figure 5] 10 is a diagram showing the relationship between the displacement of each color light and the emission timing of the color wheel. FIG. [Figure 6] FIG. 10 is a diagram showing a state in which blue light is incident on a color wheel. [Figure 7] FIG. 10 is a diagram illustrating a state in which blue light is incident on a color wheel according to a second embodiment. [Figure 8] FIG. 10 is a plan view of a color wheel according to a third embodiment. [Figure 9] FIG. 10 is a plan view of a color wheel according to a fourth embodiment. [Figure 10] FIG. 10 is a plan view of a color wheel 411A according to a modified example. [Figure 11] FIG. 10 is a plan view showing a schematic configuration of a light source device according to a fifth embodiment. [Figure 12] FIG. 13 is a plan view showing a schematic configuration of a projector according to a sixth embodiment. [Figure 13] FIG. 10 is a cross-sectional view of a light source device according to a sixth embodiment. [Figure 14] FIG. 13 is a plan view showing a schematic configuration of a projector according to a seventh embodiment. [Figure 15] FIG. 13 is a plan view showing a schematic configuration of a projector according to an eighth embodiment. [Figure 16] FIG. 13 is a plan view of a color wheel according to an eighth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] (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.

[0009] FIG. 1 is a plan view showing a schematic configuration of a projector 100 according to the present embodiment. As shown in FIG. 1, a projector 100 of this embodiment includes a light source device 1, a light modulation device 2, an incident-side polarizing plate 3, an exit-side polarizing plate 4, and a projection optical device 5. The light source device 1 includes a light source unit 10 , a color wheel 11 , a magnifying optical system 12 , a first transmitting optical element 13 , a reflecting element 15 , and a first rotating element 17 .

[0010] The following description will be given using an XYZ Cartesian coordinate system in the drawings as necessary. The X axis is an axis parallel to the illumination optical axis AX of the light source device 1. The illumination optical axis AX of the light source device 1 is defined as an axis along the chief ray of the light emitted from the light source device 1. The Y axis is an axis perpendicular to the X axis and is an axis parallel to the first rotation axis C1 of the first transmissive optical element 13 and the second rotation axis C2 of the color wheel 11. The Z axis is an axis perpendicular to the X axis and Y axis. The X-axis direction in this embodiment corresponds to the "first direction" in the claims. The Y-axis direction in this embodiment corresponds to the "second direction" in the claims. The Z-axis direction in this embodiment corresponds to the "third direction" in the claims. In the following description, the direction along each axis, such as the first rotation axis C1 or the second rotation axis C2, may be referred to simply as the "axial direction," the circumferential direction around each axis may be referred to simply as the "circumferential direction," and the direction perpendicular to each axis may be referred to simply as the "radial direction."

[0011] The light source unit 10 is disposed so that the illumination optical axis AX of the light source unit 10 is perpendicular to the illumination optical axis AX of the light source device 1. The light source unit 10 is composed of a single laser diode that emits light rays in a first wavelength band. The light rays emitted from the light source unit 10 are linearly polarized light with coherence, and are 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 light source unit 10 emits blue light (first light) B toward the +Y side. Alternatively, the light source unit 10 may be configured with multiple laser diodes, and the laser light emitted from the multiple laser diodes may be collected by a lens and incident on the color wheel 11. With this configuration, the brightness of the blue light B emitted from the light source unit 10 can be easily increased.

[0012] Blue light B emitted from light source unit 10 is incident on color wheel 11. Color wheel 11 is rotatable about a first rotation axis C1 extending along the Y-axis direction. First rotation axis C1 is connected to a first rotating element 17 formed by a motor or the like. Color wheel 11 rotates about first rotation axis C1 by being driven by first rotating element 17. As color wheel 11 rotates about first rotation axis C1, it emits illumination light L of different colors in a time-sequential manner. The configuration of color wheel 11 will be described later.

[0013] The magnifying optical system 12 includes a cylindrical concave lens 12a and a cylindrical convex lens 12b. The cylindrical concave lens 12a has no power in the Z-axis direction and negative power in the X-axis direction. The cylindrical convex lens 12b has no power in the Z-axis direction and positive power in the X-axis direction. This allows the magnifying optical system 12 to expand the beam width of the light emitted from the color wheel 11 in the X-axis direction, which is along the radial direction of the color wheel 11. In other words, the magnifying optical system 12 of this embodiment expands the illumination light L emitted from the color wheel 11 along the radial direction of the color wheel 11.

[0014] The reflecting element 15 reflects the illumination light L, the light beam width of which has been expanded by the magnifying optical system 12, and makes it incident on the first transmitting optical element 13. Therefore, the light incident on the first transmitting optical element 13 has a band-like cross-sectional shape with a major axis extending along the Y-axis direction. In the present embodiment, the longitudinal direction of the illumination light L emitted from the magnifying optical system 12 is parallel to the Y-axis direction along the first rotation axis C1 on the first incident surface of the first transmitting optical element 13.

[0015] The first transmissive optical element 13 is made of a rotatably supported light-transmitting member. The first transmissive optical element 13 is rotatable about a second rotation axis C2 extending along the Y-axis direction. The second rotation axis C2 is connected to the first rotation element 17. In this embodiment, the first rotation axis C1 and the second rotation axis C2 are coaxial, and the first rotation element 17 rotates the first transmissive optical element 13 and the color wheel 11 together. Hereinafter, when the first rotation axis C1 and the second rotation axis C2 are not particularly distinguished from each other, the rotation axis that includes the first rotation axis C1 and the second rotation axis C2 and rotates the first transmissive optical element 13 and the color wheel 11 together may be simply referred to as the rotation axis C.

[0016] The first transmissive optical element 13 is made of a translucent material such as optical glass (e.g., BK7), quartz, resin, or quartz. The first transmissive optical element 13 has a first surface 13a and a second surface 13b that intersect with the first rotation axis C1, and four first side surfaces 13c that are perpendicular to the first surface 13a and the second surface 13b. That is, the shape of the first transmissive optical element 13 is a regular rectangular prism having six flat surfaces including the first surface 13a, the second surface 13b, and the four first side surfaces 13c. The cross section of the first transmissive optical element 13 cut along a plane perpendicular to the first rotation axis C1 is a square. That is, the four first side surfaces 13c have the same area, and two opposing first side surfaces 13c are parallel to each other.

[0017] The first transmissive optical element 13 rotates about the first rotation axis C1 and transmits the illumination light L emitted from the color wheel 11 and magnified by the magnifying optical system 12. Therefore, the first side surface 13c through which the illumination light L enters the first transmissive optical element 13 is not fixed and changes over time. Similarly, the first side surface 13c through which the illumination light L entering the first transmissive optical element 13 is emitted to the external space is not fixed and changes over time. In the first transmissive optical element 13, the first side surface 13c through which the illumination light L enters is referred to as the first incident surface. The first side surface 13c through which the illumination light L entering from the first incident surface exits is referred to as the first exit surface. The first incident surface and the first exit surface change over time and are either of two of the four first side surfaces 13c that are parallel to each other.

[0018] 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 translucent member, the allowable range of parallelism of light, etc.

[0019] In this embodiment, the first transmissive optical element 13 has four first side surfaces 13c, but the number of first side surfaces 13c does not necessarily have to be four and is preferably 2×m (m: a natural number greater than or equal to 2). That is, the number of first side surfaces 13c is preferably an even number greater than or equal to 4, such as 6 or 8. If the number of first side surfaces 13c is an even number greater than or equal to 4, all of the first side surfaces 13c are parallel to the first side surface 13c opposite to the first side surface 13c, and there is no first side surface 13c that does not have a parallel pair. This reduces the generation of stray light in the first transmissive optical element 13, thereby improving light utilization efficiency.

[0020] The behavior of the illumination light L when it passes through the first transmissive optical element 13 will be described below. 2A to 2F are schematic diagrams for explaining the behavior of the illumination light L when the first transmissive optical element 13 rotates. In this example, when viewed from the +Y side, the first transmissive optical element 13 rotates clockwise around the first rotation axis C1, and time passes from FIG. 2A to FIG. 2F.

[0021] 2A to 2F, the angle formed between the illumination optical axis AX and a straight line M that passes through the first rotation axis C1 and is perpendicular to the first side surface 13c1 of the first transmissive optical element 13 is defined as the rotation angle ω of the first transmissive optical element 13. In reality, the illumination light L has a predetermined luminous flux width in the Z-axis direction, but here we will focus on the behavior of the light ray L1a that travels on the illumination optical axis AX.

[0022] 2A shows the initial state of the first transmissive optical element 13. That is, the first transmissive optical element 13 is not rotated, 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 L1a is perpendicularly incident on the first side surface 13c1 and therefore travels along the illumination optical axis AX inside the first transmissive optical element 13 without being refracted at the first side surface 13c1. Next, the light ray L1a is also perpendicularly incident on the first side surface 13c3, which is parallel to the first side surface 13c1. Therefore, the light ray is emitted from the first transmissive optical element 13 and travels along the illumination optical axis AX without being refracted at the first side surface 13c3 either.

[0023] Next, as shown in FIG. 2B , when the first transmissive optical element 13 rotates by the rotation angle ω, the light ray L1a is incident on the first side surface 13c1 at an incident angle equal to the rotation angle ω. Therefore, the light ray L1a is refracted in the direction shown in the figure (toward the +Z side) and travels inside the first transmissive optical element 13. Next, the light ray L1a is incident on the first side surface 13c3 at a predetermined incident angle, is refracted at the first side surface 13c3, and is emitted from the first transmissive optical element 13. At this time, because the first side surfaces 13c1 and 13c3 are parallel to each other, the incident angle of the light ray L1a on the first side surface 13c1 and the incident angle of the light ray L1a on the first side surface 13c3 are equal, and the refraction angle of the light ray L1a incident on the first side surface 13c1 and the refraction angle of the light ray L1a emitted from the first side surface 13c3 have opposite signs but equal absolute values. This causes the angle of refraction of light ray L1a when it enters first side surface 13c1 to cancel out the angle of refraction when it emerges from first side surface 13c3. As a result, light ray L1a travels parallel to illumination optical axis AX at a position displaced by displacement amount d from illumination optical axis AX toward the +Z side.

[0024] Next, as shown in Figure 2C, when the rotation angle ω of the first transmissive optical element 13 becomes larger than that of Figure 2B, the angle of incidence of the light ray L1a becomes larger, and the angle of refraction also becomes larger. Therefore, the displacement d of the light ray L1a from the illumination optical axis AX becomes larger than that in Figure 2B. Furthermore, the state in which the light ray L1a 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.

[0025] Next, as shown in FIG. 2D, when the rotation angle ω of the first transmissive optical element 13 exceeds 45 degrees, the incident surface of the light ray L1a changes from the first side surface 13c1 to the first side surface 13c2. At this time, the light ray L1a is refracted at the first side surface 13c2, but the refraction direction is different from that in the period up to FIG. 2C, and the light ray L1a is refracted in the direction shown in the figure (toward the -Z side). The exit surface of the light ray L1a also changes from the first side surface 13c3 to the first side surface 13c4. However, because the first side surfaces 13c2 and 13c4 are parallel to each other, the refraction angle of the light ray L1a when it enters the first side surface 13c3 and the refraction angle when it exits from the first side surface 13c4 cancel each other out, as in the period up to FIG. 2C. As a result, the light ray L1a travels parallel to the illumination optical axis AX at a position displaced by a displacement amount d toward the -Z side from the illumination optical axis AX.

[0026] Next, as shown in Fig. 2E, when the rotation angle ω of the first transmissive optical element 13 becomes larger than that in Fig. 2D, the angle of incidence of the light ray L1a becomes smaller, and the angle of refraction also becomes smaller. Therefore, the displacement d of the light ray L1a from the illumination optical axis AX becomes smaller than that in Fig. 2D. 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.

[0027] Next, as shown in FIG. 2F, when the rotation angle ω of the first transmissive optical element 13 becomes 90 degrees, the incident surface changes from the first side surface 13c1 in the initial state to the first side surface 13c2, but the behavior of the light ray L1a becomes the same as in the initial state shown in FIG. 2A.

[0028] As described above, if the first entrance surface and the first exit surface of the first transmissive optical element 13 are parallel to each other, the traveling direction of the light ray L1a does not change regardless of the rotation angle ω of the first transmissive optical element 13. Instead, the light ray L1a translates in a direction parallel to the illumination optical axis AX over time. When the rotation angle ω is 0°, the displacement d of the light ray L1a is 0. As the rotation angle ω ranges from 0° to 45°, the displacement d increases toward either the +Z or −Z side. As soon as the rotation angle ω exceeds 45°, the displacement direction reverses while the absolute value of the displacement d remains the same. 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 the rotation angle ω reaches 90°, the above behavior is repeated. Therefore, as the first transmissive optical element 13 rotates once, the displacement d of the light ray L1a repeats the above cycle four times. The displacement amount of the light ray L1a can be set appropriately by adjusting the parameters of the first transmissive optical element 13, such as the refractive index and size.

[0029] In this embodiment, the rectangular illumination light L extending in the Y-axis direction is displaced in the Z-axis direction by the rotation of the first transmissive optical element 13, thereby scanning the two-dimensional illuminated area on the illuminated surface, specifically the image forming area of ​​the light modulation device 2.

[0030] As shown in FIG. 1, the light modulation device 2 is provided on the light emission side of the light source device 1 on the illumination optical axis AX. The light modulation device 2 modulates the illumination light L emitted from the light source device 1 in accordance with image information to form image light. A transmissive liquid crystal panel is used for the light modulation device 2. In this embodiment, multiple colored lights are incident sequentially as the illumination light L, so the liquid crystal panel does not need to be equipped with a color filter. The liquid crystal panel may be driven by any method, such as twisted nematic (TN), vertical alignment (VA), or in-plane switching (IPS) methods, and is not particularly limited.

[0031] As shown in Fig. 1, the incident-side polarizing plate 3 is disposed on the light incident side of the light modulation device 2 on the illumination optical axis AX. The incident-side polarizing plate 3 transmits a linearly polarized component of the illumination light L in a specific direction. The exit-side polarizing plate 4 transmits linearly polarized light in a specific direction that is emitted from the light modulation device 2 toward the projection optical device 5. The incident-side polarizing plate 3 and the exit-side polarizing plate 4 are, for example, arranged in a crossed Nicol configuration, with their transmission axes perpendicular to each other.

[0032] The projection optical device 5 is made up of a plurality of projection lenses, and projects the image light modulated by the light modulation device 2 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.

[0033] Next, a description will be given of the configuration of the color wheel 11. FIG. 3, the color wheel 11 is a disk-shaped member made of a light-transmitting member and has a plurality of regions A. The number of the plurality of regions A is equal to the number of first side surfaces 13c of the first transmissive optical element 13. In this embodiment, the color wheel 11 has four regions A.

[0034] The four regions A include a first region A1, a second region A2, a third region A3, and a fourth region A4. The regions A1 to A4 are arranged in order in the circumferential direction of the disc-shaped color wheel 11.

[0035] The first region A1 is a region that emits blue light B incident from the light source unit 10. The first region A1 is made of a light-transmitting member 110, and transmits the blue light B. The first region A1 may have a diffusion function that transmits the blue light B in a diffused state.

[0036] The second region A2 has a first wavelength conversion layer 111 disposed therein. The first wavelength conversion layer 111 converts blue light B emitted from the light source unit 10 into red light R of a second wavelength band. The second region A2 is a region that emits red light R toward the +Y side as a second light different from the blue light B. The second wavelength band is, for example, a red wavelength band of 600 to 800 nm. The first wavelength conversion layer 111 is formed of a red phosphor (Y) in which, for example, any of Pr, Eu, and Cr is dispersed as an activator. 1-x ,Gd x )3(Al,Ga)5O 12 A YAG-based phosphor (either Pr:YAG, Eu:YAG, or Cr:YAG) consisting of the above is used. The activator may contain one element selected from Pr, Eu, and Cr, or may be a co-activator containing multiple elements selected from Pr, Eu, and Cr.

[0037] In this embodiment, the first wavelength conversion layer 111 is preferably made of a transparent phosphor that does not have any scatterers or pores that scatter the generated red light R. In this way, the first wavelength conversion layer 111 does not scatter the red light R, and therefore the light distribution and polarization state of the red light R can be easily maintained. This allows the red light R to be efficiently incident on the light modulation device 2.

[0038] The third region A3 has the second wavelength conversion layer 112 disposed therein. The second wavelength conversion layer 112 converts the blue light B emitted from the light source unit 10 into green light G in a third wavelength band. The third region A3 emits the green light G toward the +Y side as a third light different from the blue light B and the red light R. The third wavelength band is, for example, a green wavelength band of 470 to 650 nm. The second wavelength conversion layer 112 contains a green phosphor, for example, Lu3Al5O 12 :Ce 3+ Y3O4:Eu phosphor 2+ (Ba,Sr)2SiO4:Eu phosphor 2+ Ba3Si6O phosphor 12 N2:Eu 2+ (Si,Al)6(O,N)8:Eu phosphor 2+ This includes phosphor materials such as ZnO-based phosphors.

[0039] In this embodiment, the second wavelength conversion layer 112 is preferably made of a transparent phosphor that does not have any scatterers or pores that scatter the generated green light G. In this way, the second wavelength conversion layer 112 does not scatter the green light G, and therefore the light distribution and polarization state of the green light G can be easily maintained. This allows the green light G to be efficiently incident on the light modulation device 2.

[0040] The fourth region A4, like the second region A2, is a region in which the first wavelength conversion layer 111 is arranged, converts blue light B into red light R in the second wavelength band, and emits the red light R toward the +Y side. In the color wheel 11 of the present embodiment, by providing two regions that emit red light R, the proportion of the red component in the white light W can be increased.

[0041] Blue light B emitted from light source unit 10 is incident on color wheel 11 at a predetermined position. Therefore, as color wheel 11 rotates around first rotation axis C1, blue light B is incident sequentially on each of areas A1 to A4. Specifically, color wheel 11 changes the incident position of blue light B among areas A1 to A4, and sequentially emits blue light B, red light R, green light G, and red light R as illumination light L.

[0042] The above description does not take into consideration changes in color of the illumination light L incident on the first side surface 13c of the first transmissive optical element 13. However, in the projector 100 of this embodiment, the color wheel 11 sequentially makes blue light B, red light R, green light G, and red light R incident as illumination light L on the first transmissive optical element 13. Therefore, in the projector 100 of this embodiment, the color of the illumination light L scanning on the light modulation device 2 sequentially changes.

[0043] FIG. 4 is a diagram showing how illumination light L scans the light modulation device 2. As shown in FIG. 4, the illumination light L emitted from the color wheel 11 scans the image formation area 20, which is the illuminated area of ​​the light modulation device 2, from the upper end 20a to the lower end 20b in the vertical direction along the Z axis while being incident on one first side surface 13c1 of the first transmissive optical element 13. As the first transmissive optical element 13 rotates, the illumination light L repeats the behavior of scanning the image formation area 20 from the upper end 20a to the lower end 20b each time the first side surface 13c1 onto which the illumination light L is incident changes.

[0044] Now, consider a case where two colored lights are incident on a certain first side surface 13c1 during rotation of the first transmissive optical element 13. In this case, the two colored lights scan the image forming area 20 of the light modulation device 2, causing color mixing in the image light modulated by the light modulation device 2 and degrading the quality of the projected image.

[0045] In contrast, the light source device 1 of the present embodiment employs a configuration in which blue light B, red light R, green light G, and red light R sequentially emitted from the color wheel 11 can be incident on each of the first side surfaces 13c1 of the first transmissive optical element 13. In the case of the present embodiment, the number of divided regions in the color wheel 11 is equal to the number of first side surfaces 13c in the first transmissive optical element 13, which makes it easier to synchronize the emission timing of each color light from the color wheel 11 with the scanning timing of each color light due to the rotation of the first transmissive optical element 13, as will be described later.

[0046] Fig. 5 is a timing chart showing the relationship between the displacement of each color light beam scanning the illuminated area due to the rotation of the first transmissive optical element 13 and the timing at which each color light beam is emitted from the color wheel 11. In Fig. 5, the horizontal axis represents time, and the vertical axis represents the amount of displacement. In Fig. 5, the upper row shows the displacement of each color light beam, and the lower row shows the emission timing of each color light beam, thereby illustrating the correspondence between the displacement and the emission timing.

[0047] As shown in Figure 5, in the light source device 1 of this embodiment, the first period T1 during which blue light B is incident on the first region A1 of the color wheel 11 is synchronized with the second period T2 during which the blue light B emitted from the first region A1 is incident on the first side surface 13c1 of the first transmissive optical element 13.

[0048] The first period T1 is the period from time t1 when the blue light B starts to be incident on the first region A1 to time t2 when the incident on the first region A1 ends, and is the period during which the blue light B is emitted from the first region A1. The second period T2 is the period from time t3 when the blue light B emitted from the color wheel 11 starts to be incident on, for example, the first side surface 13c1 of the rotating first transmissive optical element 13 to time t4 when the incident on the first side surface 13c1 ends, and is the period during which the blue light B scans the image forming region 20 of the light modulation device 2 from the upper end 20a to the lower end 20b. That is, time t1 and time t3 coincide with each other, and time t2 and time t4 coincide with each other.

[0049] Furthermore, in the light source device 1 of this embodiment, the third period T3 during which the blue light B is incident on the second region A2 of the color wheel 11 is synchronized with the fourth period T4 during which the red light R emitted from the second region A2 is incident on the first side surface 13c2 of the first transmissive optical element 13.

[0050] The third period T3 is a period that elapses from time t5 when the blue light B starts to be incident on the second region A2 to time t6 when the incidence on the second region A2 ends, and is a period during which the red light R is emitted from the second region A2. The fourth period T4 is a period that elapses from time t7 when the red light R emitted from the color wheel 11 starts to be incident on, for example, the first side surface 13c2 of the rotating first transmissive optical element 13 to time t8 when the incidence on the first side surface 13c2 ends, and is a period during which the red light R scans the image forming region 20 of the light modulation device 2 from the upper end 20a to the lower end 20b. That is, time t5 and time t7 coincide with each other, and time t6 and time t8 coincide with each other.

[0051] Furthermore, in the light source device 1 of this embodiment, the fifth period T5 in which the blue light B is incident on the third region A3 of the color wheel 11 is synchronized with the sixth period T6 in which the green light G emitted from the third region A3 is incident on the first side surface 13c2 of the first transmissive optical element 13.

[0052] The fifth period T5 is a period that elapses from time t9 when the blue light B starts to be incident on the third region A3 to time t10 when the incidence on the third region A3 ends, and is a period during which the green light G is emitted from the third region A3. The sixth period T6 is a period that elapses from time t11 when the green light G emitted from the color wheel 11 starts to be incident on, for example, the first side surface 13c3 of the rotating first transmissive optical element 13 to time t12 when the incidence on the first side surface 13c3 ends, and is a period during which the green light G scans the image forming region 20 of the light modulation device 2 from the upper end 20a to the lower end 20b. That is, time t9 and time t11 coincide with each other, and time t10 and time t12 coincide with each other.

[0053] Furthermore, in the light source device 1 of this embodiment, the seventh period T7 in which the blue light B is incident on the fourth region A4 of the color wheel 11 is synchronized with the eighth period T8 in which the red light R emitted from the fourth region A4 is incident on the first side surface 13c4 of the first transmissive optical element 13.

[0054] The seventh period T7 is a period that elapses from time t13 when the blue light B starts to be incident on the fourth region A4 to time t14 when the incidence on the fourth region A4 ends, and is a period during which the red light R is emitted from the fourth region A4. The eighth period T8 is a period that elapses from time t15 when the red light R emitted from the color wheel 11 starts to be incident on, for example, the first side surface 13c4 of the rotating first transmissive optical element 13 to time t16 when the incidence on the first side surface 13c4 ends, and is a period during which the red light R scans the image forming region 20 of the light modulation device 2 from the upper end 20a to the lower end 20b. That is, time t13 and time t15 coincide with each other, and time t14 and time t16 coincide with each other.

[0055] In this way, the light source device 1 of this embodiment synchronizes the period during which the color wheel 11 emits blue light B, red light R, green light G, and red light R, respectively, with the period during which the blue light B, red light R, green light G, and red light R emitted from the color wheel 11 are incident on each of the first side surfaces 13c1, which are the first incident surfaces of the first transmissive optical element 13. According to this configuration, one color light is incident on each first side surface 13c when the first transmissive optical element 13 rotates. This allows each color light to independently scan the image forming area 20 of the light modulation device 2, thereby suppressing degradation in the quality of the projected image due to color mixing in the image light modulated by the light modulation device 2.

[0056] However, even when the period during which each color light is emitted from the color wheel 11 and the period during which each color light is incident on each first side surface 13c of the first transmissive optical element 13 are synchronized as described above, there is a risk that a certain amount of color mixing will occur in the image light when blue light B crosses the boundary between two regions of the color wheel 11. Below, we will explain an example where blue light B switches from being incident on the first region A1 to being incident on the second region A2.

[0057] Fig. 6 is a diagram showing the state in which blue light B is incident on the color wheel 11. In Fig. 6, the left side shows the state in which blue light B is incident on the color wheel 11 in time series, the center shows the state in which light emitted from the color wheel 11 is incident on the first transmissive optical element 13 in time series, and the right side shows the illumination state on the image forming area 20 of the light modulation device 2 in time series. Note that the three diagrams aligned at the same height in the vertical direction in Fig. 6 show diagrams of the same timing.

[0058] 6, as the color wheel 11 rotates clockwise around the second rotation axis C2, the blue light B moves radially within the first area A1. Accordingly, the blue light B moves from the upper end 20a to the lower end 20b within the image forming area 20. When the incident position of the blue light B reaches the end of the first area A1, the blue light B illuminating the image forming area 20 also reaches the lower end 20b.

[0059] 6, the blue light B crosses the boundary K between the first region A1 and the second region A2. At this time, the light emitted from the color wheel 11 includes both the blue light B from the first region A1 and the red light R from the second region A2. Specifically, the red light R emitted from the second region A2 is incident on the first side surface 13c2 of the first transmissive optical element 13 and is thereby incident on the upper end portion 20a of the image forming region 20 of the light modulation device 2, and the blue light B emitted from the first region A1 is incident on the lower end portion 20b of the image forming region 20 of the light modulation device 2 by the first side surface 13c1 of the first transmissive optical element 13. At this time, the image forming area 20 of the light modulation device 2 is simultaneously illuminated by the blue light B and the red light R. In this state, the image light modulated by the light modulation device 2 will result in degradation of image quality due to color mixing.

[0060] In contrast, in the light source device 1 of this embodiment, the output of the light source unit 10 is reduced at timing T100 when blue light B is incident on the boundary K between the first area A1 and the second area A2. In this embodiment, turning off the output of the light source unit 10 prevents light from being incident on the image forming area 20 of the light modulation device 2, thereby suppressing degradation of image quality due to color mixing. Note that, for convenience of explanation, timing T100 in FIG. 6 illustrates a state in which blue light B is tentatively emitted, and the blue light B incident on the color wheel 11 is indicated by a dashed line to distinguish it from other timings.

[0061] The light source device 1 also turns off the output of the light source unit 10 when the blue light B is incident on the boundary between two other adjacent regions. Examples of the boundary between the two other adjacent regions include the boundary between the second region A2 and the third region A3, the boundary between the third region A3 and the fourth region A4, and the boundary between the fourth region A4 and the first region A1.

[0062] (Effects of the first embodiment) The light source device 1 of this embodiment includes a light source unit 10 that emits blue light B, a color wheel 11 onto which the first light emitted from the light source unit is incident, and a first transmissive optical element 13 that is made of a light-transmitting member and has a first incident surface onto which illumination light L emitted from the color wheel 11 is incident and a first exit surface from which the illumination light L incident from the first incident surface exits. The first transmissive optical element 13 has its first incident surface and first exit surface parallel to each other, and rotates about a first rotation axis C1 that extends along a Y-axis direction that intersects with the X-axis direction, which is the incident direction of the illumination light L onto the first transmissive optical element 13, thereby scanning the illumination light L emitted from the color wheel 11 over an image formation region 20 of the light modulation device 2, which is an illuminated region. The color wheel 11 includes a first region A1 that emits blue light B incident from the light source unit 10, a second region A2 that emits red light R different from the blue light B, a third region A3 that emits green light G, and a fourth region A4 that emits the red light R, and rotates around a second rotation axis C2 extending along the Y direction. A first period T1 in which the blue light B is incident on the first region A1 is synchronized with a second period T2 in which the blue light B emitted from the first region A1 is incident on the first side surface 13c1 of the first transmissive optical element 13, and a third period T3 in which the blue light B is incident on the second region A2 is synchronized with a fourth period T4 in which the red light R emitted from the second region A2 is incident on the first side surface 13c2 of the first transmissive optical element 13.

[0063] According to the light source device 1 of this embodiment, as shown in Figures 2A to 2F, as the first transmissive optical element 13 rotates, the illumination light L can be displaced in a direction perpendicular to the traveling direction of the illumination light L while maintaining a state parallel to the illumination optical axis AX, thereby scanning the illumination light L within a two-dimensional illuminated area.

[0064] The light source device 1 of this embodiment can provide a light source device suitable for use in a single-plate sequential projector by synchronizing the emission timing of each color light from the color wheel 11 with the scanning timing of each color light due to the rotation of the first transmissive optical element 13. Furthermore, in this embodiment, the color wheel 11 and the first transmissive optical element 13 are rotated together by the first rotating element 17, which reduces the number of parts and makes it possible to miniaturize the device configuration.

[0065] According to the projector 100 equipped with the light source device 1 of this embodiment, the illumination light L can always be incident perpendicularly on the light modulation device 2. As a result, according to the projector 100 of this embodiment, it is possible to suppress the reduction in brightness and contrast in the light modulation device 2, the occurrence of color unevenness, the loss of light in the projection optical device 5, and the like, and to realize a single-panel sequential projector with excellent display quality with a simple configuration.

[0066] (Second embodiment) Next, a light source device according to a second embodiment will be described. Note that components common to the first embodiment are given the same reference numerals and descriptions thereof will be omitted. Fig. 7 is a diagram showing a state in which blue light B is incident on color wheel 11 in the light source device of this embodiment. Fig. 7 is a diagram corresponding to Fig. 6 of the first embodiment.

[0067] 7, as the color wheel 11 rotates clockwise around the first rotation axis C1, the blue light B moves radially within the first area A1. Accordingly, the blue light B moves from the upper end 20a to the lower end 20b within the image forming area 20. When the incident position of the blue light B reaches the end of the first area A1, the blue light B illuminating the image forming area 20 also reaches the lower end 20b.

[0068] As shown at timing T100, the blue light B crosses the boundary K between the first area A1 and the second area A2. At this time, the image forming area 20 of the light modulation device 2 is simultaneously illuminated by the blue light B and the green light G. In this state, the image light modulated by the light modulation device 2 will result in degradation of image quality due to color mixing.

[0069] In contrast, in the light source device of this embodiment, the amount of displacement by the first transmissive optical element 13, the area of ​​the image forming area 20, etc. are set so that during the period when at least a portion of the blue light B overlaps the boundary K between the first area A1 and the second area A2, the light emitted from the color wheel 11 enters outside the effective area of ​​the image forming area 20, which is the illuminated area.

[0070] The image forming area 20 of the light modulation device 2 includes an effective area AR1 and a non-effective area AR2 provided outside the effective area AR1 in the vertical direction. The effective area AR1 is an area where image light is formed, and the non-effective area AR2 has the same pixel structure as the effective area AR1, but is an area made up of so-called dummy pixels that are not used to form the image light.

[0071] (Effects of the second embodiment) In this embodiment, during the period when at least a portion of the blue light B overlaps the boundary K, that is, the light emitted from the color wheel 11 at the timing before and after the blue light B crosses the boundary K, can be allowed to escape to the non-effective area AR2 outside the effective area AR1. This eliminates the need to control the output of the light source unit 10 in accordance with the timing at which color mixing occurs. This makes it possible to realize a simple configuration that prevents color mixing.

[0072] (Third embodiment) Next, a light source device of a third embodiment will be described. The difference between the light source unit 10 of this embodiment and the light source device of the first embodiment is the configuration of the color wheel. Note that components common to the first embodiment are given the same reference numerals and descriptions thereof will be omitted.

[0073] FIG. 8 is a plan view of the color wheel 311 of this embodiment. 8, the color wheel 311 of this embodiment includes a first region A1, a second region A2, a third region A3, a fourth region A4, and four light-shielding regions SA. Each light-shielding region SA is disposed between two adjacent regions A and blocks blue light B incident from the light source unit 10. The light-shielding regions SA may be either absorbing or reflective of the blue light B. For example, using an absorbing region can suppress the generation of stray light within the light source device 1.

[0074] In the color wheel 311 of this embodiment, blue light B repeats a cycle of being incident in order on the first region A1, the light-shielding region SA, the second region A2, the light-shielding region SA, the third region A3, the light-shielding region SA, the fourth region A4, the light-shielding region SA, and the first region A1.

[0075] (Effects of the third embodiment) According to the light source device equipped with the color wheel 311 of this embodiment, a light-shielding area SA is provided at the boundary between adjacent areas A where blue light B is present, thereby more reliably suppressing the occurrence of color mixing caused by two colored lights crossing the boundary between areas A entering the image forming area 20.

[0076] (Fourth embodiment) Next, a light source device according to a fourth embodiment will be described. The difference between this embodiment and the first embodiment is the configuration of the color wheel. Note that components common to the first embodiment are given the same reference numerals and will not be described again.

[0077] In the light source device 1 of the first embodiment, the number of first side surfaces 13c of the first transmissive optical element 13 is four, but the number of first side surfaces is not limited to this. The number of first side surfaces of the first transmissive optical element of this embodiment is six, and the cross section of the first transmissive optical element taken along a plane perpendicular to the rotation axis has a regular hexagonal shape.

[0078] An example of the configuration of a color wheel when a regular hexagonal first transmissive optical element is used will be described below. Fig. 9 is a plan view of a color wheel 411 of this embodiment. 9, the color wheel 411 of this embodiment includes a first region A11, a second region A12, a third region A13, a fourth region A14, a fifth region A15, and a sixth region A16. The regions A11 to A16 are arranged in order in the circumferential direction of the disc-shaped color wheel 411.

[0079] The first region A11 is a region where the light-transmitting member 110 is disposed and where blue light B incident from the light source unit 10 is emitted. The second region A12 is a region where the first wavelength conversion layer 111 is disposed and where red light R is emitted. The third region A13 is a region where the second wavelength conversion layer 112 is disposed and where green light G is emitted. The fifth region A15, like the second region A12, is a region where the first wavelength conversion layer 111 is disposed and where red light R is emitted. The sixth region A16, like the third region A13, is a region where the second wavelength conversion layer 112 is disposed and where green light G is emitted.

[0080] The fourth region A14 has a third wavelength conversion layer 113 disposed therein. The third wavelength conversion layer 113 converts a portion of the blue light B emitted from the light source unit 10 into yellow light in a fourth wavelength band, and transmits another portion of the blue light B. The fourth region A14 is a region that emits white light W obtained by combining the yellow light and the blue light. The fourth wavelength band is, for example, a yellow wavelength band of 490 to 750 nm. The third wavelength conversion layer 113 contains, for example, an yttrium aluminum garnet (YAG) phosphor. Taking YAG:Ce containing cerium (Ce) as an activator as an example, materials that can be used for the third wavelength conversion layer 113 include materials obtained by mixing raw material powders containing constituent elements such as Y2O3, Al2O3, and CeO3 and causing a solid-state reaction; Y-Al-O amorphous particles obtained by wet methods such as coprecipitation and sol-gel; and YAG particles obtained by gas-phase methods such as spray drying, flame pyrolysis, and thermal plasma.

[0081] In the light source device of this embodiment, the period during which the color wheel 311 emits each of the six colored lights and the period during which the six colored lights emitted from the color wheel 311 are incident on each of the six first side surfaces of the first transmissive optical element are synchronized.

[0082] (Effects of the fourth embodiment) According to the light source device of this embodiment, six color lights independently scan the image forming area 20 of the light modulation device 2, thereby suppressing degradation in the quality of the projected image due to color mixing in the image light modulated by the light modulation device 2. Furthermore, according to the projector using the light source device of this embodiment, white light W is incident on the light modulation device 2 as illumination light L, thereby improving the brightness of the projected image.

[0083] It should be noted that the combinations of colored light emitted from the regions A11 to A16 are not limited to those described above. Fig. 10 is a plan view of a color wheel 411A according to a modified example. As shown in FIG. 10, the modified color wheel 411A has a configuration in which blue light B is emitted from the first region A11 and the fourth region A14, red light R is emitted from the second region A12 and the fifth region A15, and green light G is emitted from the third region A13 and the sixth region A16.

[0084] The modified color wheel 411A employs a configuration in which three colors of light (blue light B, red light R, and green light G) sequentially scan the image formation area 20 of the light modulation device 2 twice during one rotation of the color wheel 411A. This allows the first side surface of the first transmissive optical element to have an even number of sides, i.e., the cross-sectional shape of the first transmissive optical element to have an even polygonal shape. Therefore, since the first entrance surface and the first exit surface are configured by two first side surfaces that are parallel to each other, it is possible to realize a configuration in which the illumination light L scans a two-dimensional illuminated area as the first transmissive optical element rotates.

[0085] (Fifth embodiment) Next, a light source device according to a fifth embodiment will be described. The difference between this embodiment and the first embodiment is the configuration of the light source unit. Note that components common to the first embodiment are given the same reference numerals and will not be described again.

[0086] FIG. 11 is a plan view showing a schematic configuration of a light source device 105 of this embodiment. As shown in FIG. 11, the light source device 105 of this embodiment includes a light source section 30, a color wheel 11, a first transmissive optical element 13, a reflecting element 15, and a first rotating element 17.

[0087] The light source unit 30 of this embodiment has a plurality of light emitting elements 30a. The plurality of light emitting elements 30a are arranged along the radial direction of the color wheel 11. Each light-emitting element 30a is formed by a laser diode and emits a blue light ray B0 having a first wavelength band of, for example, 450 nm±5 nm. The light source unit 30 emits blue light B including the blue light ray B0 of each light-emitting element 30a aligned in the X-axis direction. Therefore, the cross-sectional shape perpendicular to the principal ray of the blue light B emitted by the light source unit 30 toward the +Y side is a band shape having a major axis extending along the X-axis direction and a minor axis extending along the Z-axis direction.

[0088] In this embodiment, because the blue light B emitted from the light source unit 30 has a band-like cross-sectional shape with its major axis along the X-axis direction, the illumination light L emitted from the color wheel 11 also becomes a band-like light with its major axis along the X-axis direction. The illumination light L emitted from the color wheel 11 is reflected by the reflecting element 15 and enters the first side surface 13c of the first transmissive optical element 13. That is, the multiple light rays emitted from the multiple light-emitting elements 30a are each incident on the first transmissive optical element 13 so as to be aligned in the Y-axis direction along the first rotation axis C1. The light source device 105 of this embodiment allows the illumination light L to be incident in a band-like shape in the Y-axis direction on the first side surface 13c of the first transmissive optical element 13 without using the magnifying optical system 12 used in the light source device 1 of the first embodiment.

[0089] Therefore, according to the light source device 105 of this embodiment, it is possible to omit the magnifying optical system 12 used in the light source device 1 of the first embodiment. Note that other configurations of the light source device 105 of this embodiment are the same as those of the light source device 1 of the first embodiment, and therefore description thereof will be omitted.

[0090] (Effects of the fifth embodiment) According to light source device 105 of the present embodiment, there is no need to use magnifying optical system 12 to expand the beam width of illumination light L emitted from color wheel 11, and therefore reflecting element 15 and color wheel 11 can be arranged closer to each other in the Y-axis direction. Therefore, according to light source device 105 of the present embodiment, the dimension in the Y-axis direction can be made smaller than that of light source device 1 of the first embodiment. Therefore, a projector equipped with light source device 105 of the present embodiment can be realized that is compact and has excellent display quality.

[0091] (Sixth embodiment) Next, a projector according to a sixth embodiment will be described. The main difference between this embodiment and the first embodiment is the configuration of the light source device. Note that components common to the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

[0092] FIG. 12 is a plan view showing a schematic configuration of a projector 600 of this embodiment. As shown in FIG. 12, a projector 600 of this embodiment includes a light source device 106, a light modulation device 2, an exit-side polarizing plate 4, and a projection optical device 5. The light source device 106 includes a light source unit 10, a color wheel 611, a collimator optical system 31, a lens integrator 32, a polarization conversion element 33, a superimposing lens 34, a reflecting element 15, a first transmitting optical element 13, a first rotating element 17, and a relay optical system 6.

[0093] The color wheel 611 rotates around a rotation axis C, thereby emitting illumination light L of different colors in a time-sequential manner. The basic structure of the color wheel 611 of this embodiment is the same as that of the color wheel 11 of the light source device 1 of the first embodiment, but differs in that the first wavelength conversion layer 111 that generates red light R and the second wavelength conversion layer 112 that generates green light G contain scattering elements such as pores or scatterers. Furthermore, in the color wheel 611 of this embodiment, the light-transmitting member 110 provided in the first region A1 is composed of a diffuser plate with light-scattering properties. According to the color wheel 611 of this embodiment, blue light B, red light R, green light G, and red light R can be emitted in that order as the illumination light L in a diffused state. In this embodiment, blue light B, red light R, green light G, and red light R are diffused lights, and therefore there is variation in the polarization direction of each light. In other words, blue light B, red light R, green light G, and red light R are not linearly polarized lights.

[0094] The collimator optical system 31 collimates the illumination light L emitted from the color wheel 611 and guides it to the lens integrator 32. The collimator optical system 31 is made up of a pair of convex lenses 31a and 31b.

[0095] The lens integrator 32 has a first multi-lens array 32a and a second multi-lens array 32b. The first multi-lens array 32a is configured, for example, by arranging a plurality of first small lenses 32am in a plane. The first multi-lens array 32a splits the illumination light L emitted from the color wheel 611 and collimated by the collimator optical system 31 into a plurality of small beams by each of the first small lenses 32am and focuses each of the beams.

[0096] The second multi-lens array 32b has, for example, a plurality of second small lenses 32bm arranged in a plane corresponding to each of the first small lenses 32am of the first multi-lens array 32a. In this embodiment, the second multi-lens array 32b, together with a superimposing lens 34 described later, causes images of each of the first small lenses 32am of the first multi-lens array 32a to be incident on the first side surface 13c of the first transmissive optical element 13 in a superimposed manner.

[0097] Fig. 13 is a cross-sectional view of light source device 106 taken along the XZ plane. For ease of explanation, reflecting element 15 is omitted from Fig. 13, and the optical path of illumination light L emitted from color wheel 611 is shown as a straight line.

[0098] 12 and 13, the first small lenses 32am of the first multi-lens array 32a and the second small lenses 32bm of the second multi-lens array 32b are arranged in, for example, two rows in the X-axis direction and eight rows in the Z-axis direction. Each of the first small lenses 32am and each of the second small lenses 32bm has a rectangular planar shape with its longer side in the Y-axis direction and its shorter side in the Z-axis direction.

[0099] Based on this configuration, the lens integrator 32 can convert the illumination light L from the color wheel 611 into an illumination light beam having a cross-sectional shape that illuminates the entire image forming area 20 of the light modulation device 2 in the horizontal direction along the Y-axis direction in the image forming area 20, and illuminates a portion of the image forming area 20 in the vertical direction along the Z-axis direction.

[0100] 12, the polarization conversion element 33 is composed of two pairs of polarization conversion prism units 35, one on each side of the optical axis of the illumination light L. The polarization conversion prism unit 35 has a polarization separation surface 33a and a reflecting surface 33b that transmit one of the two polarization components contained in the illumination light L (for example, S-polarized light) as is and reflect the other polarization component (for example, P-polarized light) toward the illumination optical axis.

[0101] A retardation plate 36 made of a λ / 2 wavelength plate is provided on the S-polarized light transmitting surface of each polarization conversion prism unit 35, and all polarized light of the illumination light beam emerging from the polarization conversion element 33 is converted into P-polarized light.

[0102] The illumination light L, whose polarization direction has been converted to P-polarized light by the polarization conversion element 33, enters the first transmissive optical element 13 via the superimposing lens 34. As shown in FIGS. 12 and 13 , the illumination light L that has passed through the first transmissive optical element 13 passes through the relay optical system 6 and is superimposed on the image forming area 20 of the light modulation device 2. The illumination light L is scanned in the Z-axis direction on the image forming area 20 in accordance with the rotation of the first transmissive optical element 13. In this embodiment, the relay optical system 6 is composed of a cylindrical lens that has positive power in the XZ plane and no power in the XY plane.

[0103] (Effects of the sixth embodiment) According to the projector 600 of this embodiment, even if the polarization state of the illumination light L varies due to being emitted as diffused light from the color wheel 611, the polarization conversion element 33 can align the polarization direction of the illumination light L to P-polarized light. Therefore, linearly polarized light can be incident on the light modulation device 2, making it possible to omit an incident-side polarizing plate from the stage preceding the light modulation device 2. Furthermore, in this embodiment, the illumination light L becomes diffused light, which can improve the uniformity of the illuminance distribution of the illumination light L. Therefore, according to the projector 600 of this embodiment, the display quality can be further improved by irradiating the light modulation device 2 with uniform illumination light L.

[0104] Seventh embodiment Next, a projector according to a seventh embodiment will be described. The main difference between this embodiment and the first embodiment is the configuration of the light source device. Note that components common to the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

[0105] FIG. 14 is a plan view showing a schematic configuration of a projector 700 of this embodiment. As shown in FIG. 14, a projector 700 of this embodiment includes a light source device 107, a light modulation device 2, an incident-side polarizing plate 3, an exit-side polarizing plate 4, and a projection optical device 5. The light source device 107 includes a light source unit 10, a color wheel 11, a magnifying optical system 12, a reflecting element 15, a first transmitting optical element 13, a first rotating element 17, a second transmitting optical element 14, and a second rotating element 16.

[0106] The second transmissive optical element 14 has the same configuration as the first transmissive optical element 13, but is placed in a position where the first transmissive optical element 13 is rotated by 90 degrees around the X axis. The second transmissive optical element 14 is made of a rotatably supported light-transmitting member. The second transmissive optical element 14 is rotatable about a third rotation axis C3 extending along the Y-axis direction. The third rotation axis C3 is connected to the second rotating element 16.

[0107] The second transmissive optical element 14 has a third surface 14a and a fourth surface 14b that intersect with the third rotation axis C3, and four second side surfaces 14c that are perpendicular to the third surface 14a and the fourth surface 14b. That is, the shape of the second transmissive optical element 14 is a regular quadrangular prism having six flat surfaces including the third surface 14a, the fourth surface 14b, and the four second side surfaces 14c. The cross-sectional shape of the second transmissive optical element 14 taken along a plane perpendicular to the third rotation axis C3 is a square. That is, the four second side surfaces 14c have the same area, and two opposing second side surfaces 14c are parallel to each other.

[0108] The second transmissive optical element 14 transmits the illumination light L emitted from the first transmissive optical element 13 while rotating about the third rotation axis C3. Therefore, the second side surface 14c, onto which the illumination light L emitted from the first transmissive optical element 13 enters the second transmissive optical element 14, is not fixed but changes over time. In the second transmissive optical element 14, the second side surface 14c onto which the illumination light L enters is referred to as the second incident surface. The second side surface 14c from which the illumination light L incident from the second incident surface exits is referred to as the first exit surface. The second incident surface and the second exit surface change over time and are either two of the four second side surfaces 14c that are parallel to each other.

[0109] The second transmissive optical element 14 has four second side surfaces 14c, but the number of second side surfaces 14c does not necessarily have to be four; it is preferable that the number be 2×n (n: a natural number greater than or equal to 2). That is, it is preferable that the number of second side surfaces 14c be an even number, such as six or eight. If the number of second side surfaces 14c is an even number, all of the second side surfaces 14c are parallel to the second side surface 14c opposite the second side surface 14c, and no second side surfaces 14c are not parallel. This reduces the generation of stray light in the second transmissive optical element 14, thereby improving light utilization efficiency.

[0110] (Effects of the Seventh Embodiment) According to the projector 700 of this embodiment, the illumination light L can be scanned in the Y-axis direction by the first transmissive optical element 13, and the illumination light L can be scanned in the Z-axis direction by the second transmissive optical element 14. As a result, the illumination light L emitted from the color wheel 11 is scanned within the image formation area 20 of the light modulation device 2, which is a two-dimensional illuminated area on the illuminated surface. Therefore, according to the projector 700 of this embodiment, even when the illumination light L is scanned two-dimensionally, the reduction in brightness and contrast in the light modulation device 2, the occurrence of color unevenness, and the loss of light in the projection optical device 5 are suppressed, and the same effects as those of the first embodiment can be obtained, such as realizing a single-plate sequential type projector with excellent display quality and a simple configuration. Furthermore, since there is no need to expand the beam width of illumination light L emitted from color wheel 11 using magnifying optical system 12, reflecting element 15 and color wheel 11 can be arranged closer to each other in the Y-axis direction. Therefore, light source device 107 of this embodiment can have a more compact device configuration than light source device 1 of the first embodiment.

[0111] A Dove prism may be disposed between the first transmissive optical element 13 and the second transmissive optical element 14, and the image of light emerging from the first transmissive optical element 13 may be rotated 90 degrees before being incident on the second transmissive optical element 14. For example, if the cross-sectional shapes of the first transmissive optical element 13 and the second transmissive optical element 14 are different, it may be possible to adopt a configuration in which the first transmissive optical element 13 and the second transmissive optical element 14 rotate coaxially. With this configuration, the first transmissive optical element 13, the second transmissive optical element 14, and the color wheel 11 are rotated integrally by a single rotating element, thereby reducing the number of parts and enabling the device configuration to be made more compact.

[0112] (Eighth embodiment) Next, a projector according to an eighth embodiment will be described. The projector according to this embodiment is a three-plate type having three light modulation elements, which differs from the first embodiment, which is a single-plate type projector. Note that components common to the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

[0113] Fig. 15 is a plan view showing a schematic configuration of a projector 800 of this embodiment. Fig. 16 is a plan view of a color wheel of this embodiment. As shown in Figure 15, the projector 800 of this embodiment includes a light source device 108, a color separation element 7, a first mirror 8a, a second mirror 8b, a third mirror 8c, a fourth mirror 8d, a blue light modulation device 2B, a green light modulation device 2G, a red light modulation device 2R, a blue entrance side polarizer 3B, a blue exit side polarizer 4B, a green entrance side polarizer 3G, a green exit side polarizer 4G, a red entrance side polarizer 3R, a red exit side polarizer 4R, an image light combining element 9, and a projection optical device 5.

[0114] The light source device 108 includes a light source unit 10, a color wheel 811, a magnifying optical system 12, a first transmissive optical element 13, a reflecting element 15, and a first rotating element 17. As shown in FIG. 16 , the color wheel 811 of this embodiment includes a first region A21 and a second region A22. The first region A21 and the second region A22 are arranged side by side in the circumferential direction of the disc-shaped color wheel 811, and together they form a ring-shaped region. In the circumferential direction of the color wheel 811, the length of the first region A21 is shorter than the length of the second region A22.

[0115] The first region A21 is a region where the light-transmitting member 810 is arranged and where blue light B incident from the light source unit 10 is emitted. The second region A22 is a region where the fourth wavelength conversion layer 812 that converts part of the blue light B emitted from the light source unit 10 into yellow light of a fourth wavelength band is arranged and where yellow light Y is emitted. Based on this configuration, the light source device 108 of this embodiment is configured to sequentially emit blue light B and yellow light Y as illumination light L from the color wheel 811.

[0116] In this embodiment, the illumination light L transmitted through the first transmission optical element 13 is incident on the color separation element 7. The color separation element 7 is composed of a cross prism, and has a first optical layer 7a and a second optical layer 7b arranged perpendicular to each other. The first optical layer 7a is composed of a dichroic mirror that reflects blue light B and transmits yellow light Y. The second optical layer 7b is composed of a dichroic mirror that reflects red light R, which is the red component of the yellow light Y, and transmits blue light B and green light G, which is the green component of the yellow light Y. Based on this configuration, the color separation element 7 separates the illumination light L into blue light B, green light G, and red light R by reflecting blue light B to the -Y side, reflecting yellow light Y to the +Y side, and transmitting green light G to the +X side.

[0117] The green light G separated by the color separation element 7 passes through a green incident-side polarizing plate 3G and scans a green light modulation device 2G. The green light modulation device 2G modulates the green light G in accordance with image information to form green image light. The green image light passes through a green exit-side polarizing plate 4G and enters an image light combining element 9.

[0118] The red light R separated by the color separation element 7 is reflected by the first mirror 8a and the second mirror 8b, and passes through the red incident-side polarizing plate 3R to scan the red light modulation device 2R. The red light modulation device 2R modulates the red light R in accordance with image information to form red image light. The red image light passes through the red exit-side polarizing plate 4R and enters the image light combining element 9.

[0119] The blue light B separated by the color separation element 7 is reflected by the third mirror 8c and the fourth mirror 8d, and passes through the blue incident-side polarizing plate 3B to scan the blue light modulation device 2B. The blue light modulation device 2B modulates the blue light B according to image information to form blue image light. The blue image light passes through the blue exit-side polarizing plate 4B and enters the image light combining element 9. The image light combining element 9 combines the image lights of the respective colors and emits the combined image light toward the projection optical device 5. The image light combining element 9 may be, for example, a cross dichroic prism.

[0120] (Effects of the eighth embodiment) According to the projector 800 of this embodiment, it is possible to make each color light always perpendicularly incident on each of the light modulation devices 2B, 2G, and 2R. As a result, according to the projector 800 of this embodiment, it is possible to suppress the reduction in brightness and contrast in each of the light modulation devices 2B, 2G, and 2R, the occurrence of color unevenness, and the loss of light in the projection optical device 5, and it is possible to realize a three-plate type projector with excellent display quality with a simple configuration.

[0121] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. In addition, the specific 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.

[0122] A summary of this disclosure is provided below. (Appendix 1) a light source unit that emits a first light; a color wheel onto which the first light emitted from the light source unit is incident; a first transmissive optical element made of a light-transmitting member, the first transmissive optical element having a first entrance surface onto which light emitted from the color wheel is incident and a first exit surface from which the light incident from the first entrance surface exits; the first transmissive optical element has the first entrance surface and the first exit surface parallel to each other, and rotates about a first rotation axis extending along a second direction intersecting a first direction that is an incident direction of the light to the first transmissive optical element, thereby scanning the light emitted from the color wheel over an illuminated area; the color wheel includes a first region that emits the first light incident from the light source unit and a second region that emits a second light different from the first light, and rotates about a second rotation axis that extends along the second direction; a first period during which the first light is incident on the first region is synchronized with a second period during which the first light emitted from the first region is incident on the first incident surface of the first transmissive optical element; a third period in which the first light is incident on the second region is synchronized with a fourth period in which the second light emitted from the second region is incident on the first incident surface of the first transmissive optical element; Light source device.

[0123] With this light source device, the illumination light can be displaced in a direction perpendicular to the direction of travel of the illumination light while remaining parallel to the illumination optical axis as the first transmissive optical element rotates, allowing the illumination light to be scanned one-dimensionally within the illuminated area. With this light source device, the emission timing of each color light from the color wheel can be synchronized with the scanning timing of each color light due to the rotation of the first transmissive optical element, thereby realizing a light source device suitable for use in a single-plate sequential projector.

[0124] (Appendix 2) the first rotation shaft and the second rotation shaft are coaxial, and the device further includes a first rotation element that rotates the first transmission optical element and the color wheel together. 10. The light source device of claim 1.

[0125] With this configuration, the light source device rotates the color wheel and the first transmissive optical element together using the first rotating element, reducing the number of parts and thereby making the device more compact. It also makes it easier to synchronize the emission timing of each color light from the color wheel with the scanning timing of each color light caused by the rotation of the first transmissive optical element.

[0126] (Appendix 3) reducing the output of the light source unit at a timing when the first light is incident on the boundary between the first region and the second region; 10. The light source device according to claim 1 or 2.

[0127] With this configuration, the output of the light source is reduced when the first light crosses the boundary between the first and second regions, thereby reducing the amount of the first and second light simultaneously incident on the illuminated region, thereby suppressing color mixing in the illuminated region.

[0128] (Appendix 4) the light emitted from the color wheel during a period in which at least a portion of the first light overlaps the boundary between the first region and the second region is incident on a non-effective area outside an effective area of ​​the illuminated region; 10. The light source device according to claim 1 or 2.

[0129] With this configuration, the light emitted from the color wheel can be directed to the ineffective area outside the effective area just before and after the first light crosses the boundary. This eliminates the need to control the output of the light source unit in accordance with the timing at which color mixing occurs. This makes it possible to provide a simple configuration that prevents color mixing.

[0130] (Appendix 5) the color wheel further includes a light-shielding region that is disposed between the first region and the second region in a circumferential direction and that blocks the first light incident from the light source unit; the first light is incident on the first region, the light-shielding region, and the second region in this order; 10. The light source device according to claim 1 or 2.

[0131] According to this configuration, it is possible to suppress the occurrence of color mixing caused by the first light crossing the boundary between the first region and the second region, which occurs when the first light and the second light enter the illuminated region.

[0132] (Appendix 6) a first wavelength conversion layer that converts the first light into the second light is disposed in the second region of the color wheel; the first wavelength conversion layer is a transparent phosphor that does not scatter the second light; 6. A light source device according to any one of claims 1 to 5.

[0133] According to this configuration, the first wavelength conversion layer does not scatter the second light, and therefore the light distribution and polarization state of the second light are easily maintained.

[0134] (Appendix 7) a second wavelength conversion layer disposed in the second region of the color wheel and converting the first light into the second light; a collimating optical system that collimates the light emitted from the color wheel; a lens integrator onto which the light collimated by the collimating optical system is incident; a polarization conversion element that converts the polarization direction of the light incident from the lens integrator; a superimposing lens onto which the light emitted from the polarization conversion element is incident, the second wavelength-converting layer includes scattering elements that scatter the second light; 6. A light source device according to any one of claims 1 to 5.

[0135] With this configuration, even if the polarization state of the illumination light varies due to the illumination light being emitted as diffused light from the color wheel, the polarization conversion element can align the polarization direction of the illumination light in one direction. Therefore, for example, linearly polarized light can be incident on the light modulation device, so an incident-side polarizing plate can be omitted from the upstream stage of the light modulation device. Furthermore, because the illumination light becomes diffused light, the uniformity of the illuminance distribution of the illumination light can be improved.

[0136] (Appendix 8) the first transmissive optical element has a first surface and a second surface intersecting the first rotation axis, and 2×m (m: a natural number equal to or greater than 2) first side surfaces in contact with the first surface and the second surface, The first entrance surface and the first exit surface are two of the 2×m first side surfaces that are parallel to each other. 8. A light source device according to any one of claims 1 to 7.

[0137] According to this configuration, there is no light incident on the second side surfaces that are not parallel to each other, so that the generation of stray light in the first transmissive optical element is small, and light utilization efficiency can be improved.

[0138] (Appendix 9) the color wheel has a plurality of regions including the first region and the second region; The number of the plurality of regions is equal to the number of the first sides. 9. The light source device according to claim 8.

[0139] With this configuration, the number of divided areas of the color wheel is equal to the number of sides of the first transmissive optical element, making it easier to synchronize the emission timing of each color light on the color wheel with the scanning timing of each color light due to the rotation of the first transmissive optical element.

[0140] (Appendix 10) the light source unit has a plurality of light-emitting elements arranged along a radial direction of the color wheel, a plurality of light beams emitted from the plurality of light-emitting elements are incident on the first transmissive optical element so as to be aligned along the first rotation axis; 10. A light source device according to any one of claims 1 to 9.

[0141] According to this configuration, the light rays emitted from the plurality of light emitting elements can be incident on the first entrance surface of the first transmissive optical element in a band-like shape extending in a direction along the first rotation axis, thereby enabling the illumination light to be scanned two-dimensionally within the illuminated area as the first transmissive optical element rotates.

[0142] (Appendix 11) further comprising an expansion optical system that expands the light emitted from the color wheel along a radial direction of the color wheel; a longitudinal direction of the light emitted from the magnifying optical system is parallel to a direction along the first rotation axis on the first incident surface of the first transmissive optical element; 10. A light source device according to any one of claims 1 to 9.

[0143] According to this configuration, the light beam is magnified by the magnifying optical system, so that a strip of light extending in a direction along the first rotation axis can be incident on the first entrance surface of the first transmissive optical element, thereby allowing the illumination light to be scanned two-dimensionally within the illuminated area as the first transmissive optical element rotates.

[0144] (Appendix 12) a second transmissive optical element made of a light-transmitting member, the second transmissive optical element having a second incident surface onto which the first light is incident and a second exit surface from which the first light incident from the second incident surface exits; the second transmissive optical element has the second entrance surface and the second exit surface parallel to each other, and rotates about a third rotation axis extending along a third direction intersecting the first direction and the second direction, thereby two-dimensionally scanning the light emitted from the color wheel over an illuminated area. 12. A light source device according to any one of claims 1 to 11.

[0145] According to this configuration, as each transmissive optical element rotates, the illumination light is displaced in a direction perpendicular to the direction of travel of the illumination light while remaining parallel to the illumination optical axis, allowing the illumination light to be scanned two-dimensionally within the illuminated area.

[0146] (Appendix 13) a light source device according to any one of Supplementary Note 1 to Supplementary Note 12; a light modulation device that modulates the light emitted from the light source device based on image information; a projection optical device that projects the light modulated by the light modulation device, projector.

[0147] According to a projector having this configuration, since it is equipped with a light source device having the above configuration, light can be made to be perpendicularly incident on the light modulation device, which reduces the reduction in brightness and contrast in the light modulation device, the occurrence of color unevenness, and the loss of light in the projection optical device, making it possible to provide a compact projector with excellent display quality. [Explanation of symbols]

[0148] 1,106,107,108...light source device, 2,2B...light modulation device, 5...projection optical device, 10,30...light source section, 11,311,411,411A,611,811...color wheel, 12...magnifying optical system, 13...first transmission optical element, 13a...first surface, 13b...second surface, 13c, 13c1, 13c2, 13c3, 13c4...first side surface, 14...second transmission optical element, 15...first rotation element, 30a...light emitting element, 32...lens integrator, 33...polarization conversion element, 34...superimposing lens, 100,6 00,700,800...projector, 110,810...transparent member, 111...first wavelength conversion layer, 112...second wavelength conversion layer, A, A1, A11...area, A1, A11, A21...first area, A2, A12, A22...second area, AR1...effective area, B...blue light (first light), C...rotation axis, C1...first rotation axis, C2...second rotation axis, C3...third rotation axis, K...boundary, L1a...light ray, SA...light-shielding area, T1...first period, T2...second period, T3...third period, T4...fourth period, T100...timing.

Claims

1. a light source unit that emits a first light; a color wheel onto which the first light emitted from the light source unit is incident; a first transmissive optical element made of a light-transmitting member, the first transmissive optical element having a first entrance surface onto which light emitted from the color wheel is incident and a first exit surface from which the light incident from the first entrance surface exits; the first transmissive optical element has the first entrance surface and the first exit surface parallel to each other, and rotates about a first rotation axis extending along a second direction intersecting a first direction that is an incident direction of the light to the first transmissive optical element, thereby scanning the light emitted from the color wheel over an illuminated area; the color wheel includes a first region that emits the first light incident from the light source unit and a second region that emits a second light different from the first light, and rotates about a second rotation axis that extends along the second direction; a first period during which the first light is incident on the first region is synchronized with a second period during which the first light emitted from the first region is incident on the first incident surface of the first transmissive optical element; a third period in which the first light is incident on the second region is synchronized with a fourth period in which the second light emitted from the second region is incident on the first incident surface of the first transmissive optical element; Light source device.

2. the first rotation shaft and the second rotation shaft are coaxial, and the device further includes a first rotation element that rotates the first transmission optical element and the color wheel together. The light source device according to claim 1 .

3. reducing the output of the light source unit at a timing when the first light is incident on the boundary between the first region and the second region; 3. The light source device according to claim 1.

4. the light emitted from the color wheel during a period in which at least a portion of the first light overlaps the boundary between the first region and the second region is incident on a non-effective area outside an effective area of ​​the illuminated region; 3. The light source device according to claim 1.

5. the color wheel further includes a light-shielding region that is disposed between the first region and the second region in a circumferential direction and that blocks the first light incident from the light source unit; the first light is incident on the first region, the light-shielding region, and the second region in this order; 3. The light source device according to claim 1.

6. a first wavelength conversion layer that converts the first light into the second light is disposed in the second region of the color wheel; the first wavelength conversion layer is a transparent phosphor that does not scatter the second light; 3. The light source device according to claim 1.

7. a second wavelength conversion layer disposed in the second region of the color wheel and converting the first light into the second light; a collimating optical system that collimates the light emitted from the color wheel; a lens integrator onto which the light collimated by the collimating optical system is incident; a polarization conversion element that converts the polarization direction of the light incident from the lens integrator; a superimposing lens onto which the light emitted from the polarization conversion element is incident, the second wavelength-converting layer includes scattering elements that scatter the second light.

3. The light source device according to claim 1.

8. the first transmissive optical element has a first surface and a second surface intersecting the first rotation axis, and 2×m (m: a natural number equal to or greater than 2) first side surfaces tangent to the first surface and the second surface, The first entrance surface and the first exit surface are two first side surfaces parallel to each other among the 2×m first side surfaces.

3. The light source device according to claim 1.

9. the color wheel has a plurality of regions including the first region and the second region; the number of the plurality of regions is equal to the number of the first sides; The light source device according to claim 8 .

10. the light source unit has a plurality of light-emitting elements arranged along a radial direction of the color wheel, a plurality of light beams emitted from the plurality of light-emitting elements are incident on the first transmissive optical element so as to be aligned along the first rotation axis, 3. The light source device according to claim 1.

11. further comprising an expansion optical system that expands the light emitted from the color wheel along a radial direction of the color wheel; a longitudinal direction of the light emitted from the magnifying optical system is parallel to a direction along the first rotation axis on the first incident surface of the first transmissive optical element; 3. The light source device according to claim 1.

12. a second transmissive optical element made of a light-transmitting member, the second transmissive optical element having a second incident surface onto which the first light is incident and a second exit surface from which the first light incident from the second incident surface exits; the second transmissive optical element has the second entrance surface and the second exit surface parallel to each other, and rotates about a third rotation axis extending along a third direction intersecting the first direction and the second direction, thereby two-dimensionally scanning the light emitted from the color wheel over an illuminated area.

3. The light source device according to claim 1.

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

Images