Projector and light modulation device

Abstract

A projector and a light modulation device capable of controlling the temperature of a liquid crystal layer with high precision are provided. [Solution] The projector includes a light source and a light modulation device that modulates light emitted from the light source. The light modulation device includes a liquid crystal layer, an incident-side substrate located on the light incident side of the liquid crystal layer, an exit-side substrate located on the light exit side of the liquid crystal layer and sandwiching the liquid crystal layer together with the incident-side substrate, an incident-side dustproof substrate that is translucent and located on the light incident side of the incident-side substrate, an exit-side dustproof substrate that is translucent and located on the light exit side of the exit-side substrate and sandwiching the liquid crystal layer, incident-side substrate, and exit-side substrate together with the incident-side dustproof substrate, and a temperature control unit that controls the temperature of the liquid crystal layer. When viewed from the light incident side of the light modulation device, the planar size of the incident-side dustproof substrate is larger than the planar size of the incident-side substrate, and the temperature control unit is in contact with the incident-side dustproof substrate.

Description

[Technical Field]

[0001] The present disclosure relates to a projector and a light modulation device. [Background technology]

[0002] BACKGROUND ART Conventionally, a temperature adjustment mechanism for heating a liquid crystal panel has been known (see, for example, Patent Document 1). The temperature adjustment mechanism described in Patent Document 1 includes a light-transmitting temperature application unit and a temperature control unit connected to the temperature application unit. The temperature application unit is attached to the liquid crystal display element. The liquid crystal display element has a first substrate and a second substrate facing each other and a liquid crystal layer interposed between the first and second substrates, and the temperature application unit is formed on the second substrate. The first substrate is provided with a plurality of column electrodes arranged in stripes, and the second substrate is provided with a plurality of row electrodes perpendicular to the column electrodes. Both the column electrodes and the row electrodes are display electrodes and are formed from a transparent conductive film such as an ITO film. The light-transmitting temperature application section is provided, for example, on the surface of the second substrate facing the liquid crystal layer. The temperature application section is formed from a conductive metal oxide thin film. When a predetermined current signal is input to the metal oxide thin film, a current flows through the thin film, generating Joule heat according to the resistance value of the thin film. This makes it possible to heat the liquid crystal display element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-139018 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the temperature adjustment mechanism described in Patent Document 1, the temperature application unit is provided in an area of ​​the liquid crystal panel through which light passes. Although the temperature application unit is made of a transparent conductive film, the transparent conductive film does not transmit all of the incident light but absorbs some of the transmitted light. Therefore, when light passes through the temperature application unit, heat is generated in the temperature application unit, which causes the temperature of the liquid crystal layer to rise, making it difficult to accurately control the temperature of the liquid crystal layer. For this reason, there has been a demand for a configuration that can control the temperature of the liquid crystal layer with high precision. [Means for solving the problem]

[0005] a temperature control unit that controls a temperature of the liquid crystal layer; an incident-side substrate that is located on the light incident side of the liquid crystal layer; an exit-side substrate that is located on the light exit side of the liquid crystal layer and that sandwiches the liquid crystal layer together with the incident-side substrate; an incident-side dustproof substrate that is light transmissive and located on the light incident side of the incident-side substrate; an exit-side dustproof substrate that is light transmissive and located on the light exit side of the exit-side substrate and that sandwiches the liquid crystal layer, the incident-side substrate, and the exit-side substrate together with the incident-side dustproof substrate; and a temperature control unit that controls a temperature of the liquid crystal layer;

[0006] an optical modulation device according to a second aspect of the present disclosure, the optical modulation device comprising: a liquid crystal layer; an incident-side substrate located on the light incident side of the liquid crystal layer; an output-side substrate located on the light output side of the liquid crystal layer and sandwiching the liquid crystal layer together with the incident-side substrate; an incident-side dustproof substrate having light transparency and located on the light incident side of the incident-side substrate; an output-side dustproof substrate having light transparency and located on the light output side of the output-side substrate and sandwiching the liquid crystal layer, the incident-side substrate, and the output-side substrate together with the incident-side dustproof substrate; and a temperature control unit that controls a temperature of the liquid crystal layer, wherein the incident-side dustproof substrate has a larger planar size than the incident-side substrate, and the temperature control unit is in contact with the incident-side dustproof substrate. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing a schematic configuration of a projector according to a first embodiment. [Figure 2] FIG. 1 is a perspective view showing a part of an image forming apparatus according to a first embodiment. [Figure 3] FIG. 1 is a perspective view showing a part of an image forming apparatus according to a first embodiment. [Figure 4] FIG. 2 is a perspective view showing a panel module according to the first embodiment. [Figure 5] FIG. 2 is a perspective view showing a panel module according to the first embodiment. [Figure 6] FIG. 2 is an exploded perspective view showing the panel module according to the first embodiment. [Figure 7] FIG. 2 is an exploded perspective view showing the panel module according to the first embodiment. [Figure 8] FIG. 2 is a cross-sectional view showing the panel module according to the first embodiment. [Figure 9] FIG. 2 is a perspective view showing a part of the image forming apparatus in a state where the light modulation device is separated from the support member in the first embodiment. [Figure 10] FIG. 2 is a diagram showing an optical path changing element according to the first embodiment. [Figure 11] 5A and 5B are diagrams for explaining an optical path shift caused by an optical path changing element in the first embodiment. [Figure 12]FIG. 3 is a diagram showing the positional relationship between the heating element and the actuator as viewed from the blue light incident side in the first embodiment. [Figure 13] FIG. 4 is a diagram showing the positional relationship between the heating element and the actuator as viewed from the red light incident side in the first embodiment. [Figure 14] FIG. 3 is a diagram showing the positional relationship between a heating element and an actuator as viewed from the light emission side of the optical path changing element in the first embodiment. [Figure 15] FIG. 2 is a perspective view showing a part of the image forming apparatus and a cooling device according to the first embodiment. [Figure 16] FIG. 2 is an exploded perspective view showing the cooling device according to the first embodiment. [Figure 17] FIG. 3 is a cross-sectional view showing a heat transfer frame and an incident-side dustproof substrate in the first embodiment. [Figure 18] FIG. 2 is a block diagram showing the configuration of a control device according to the first embodiment. [Figure 19] FIG. 3 is a diagram showing the position of a temperature sensor on a liquid crystal panel in the first embodiment. [Figure 20] 4 is a flowchart showing a control process in the first embodiment. [Figure 21] FIG. 10 is a perspective view showing an image forming apparatus provided in a projector according to a second embodiment. [Figure 22] FIG. 10 is a diagram showing an optical path changing element according to a second embodiment. [Figure 23] 10A and 10B are diagrams for explaining an optical path shift caused by an optical path changing element in the second embodiment. [Figure 24] FIG. 10 is a diagram showing the positional relationship between the heating element and the actuator as viewed from the blue light incident side in the second embodiment. [Figure 25] FIG. 10 is a diagram showing the positional relationship between a heating element and an actuator as viewed from the light emission side of an optical path changing element in a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] [First embodiment] Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings. [Projector configuration] FIG. 1 is a schematic diagram showing the general configuration of a projector 1 according to this embodiment. 1, a projector 1 according to this embodiment modulates a light beam emitted from a light source 31 to form image light PL according to image information, and enlarges and projects the formed image light PL onto a projection surface PS such as a screen. The projector 1 includes an exterior housing 2, and an image projection device 3, a cooling device 6, and a control device 7 housed within the exterior housing 2. In addition, although not shown, the projector 1 includes a power supply device that supplies power to the electronic components that make up the projector 1.

[0009] [Configuration of image projection device] The image projection device 3 forms and projects the image light PL described above. The image projection device 3 includes a light source 31, a color separation device 32, an image formation device 33, and a projection optical device 37. In the following description, the three mutually orthogonal directions are referred to as the +D1 direction, +D2 direction, and +D3 direction. Of these, the +D1 direction is the direction in which the light source 31 emits illumination light WL, and the +D2 direction and +D3 direction are referred to as directions that are orthogonal to the +D1 direction and are orthogonal to each other. The direction opposite to the +D1 direction is referred to as the -D1 direction, the direction opposite to the +D2 direction is referred to as the -D2 direction, and the direction opposite to the +D3 direction is referred to as the -D3 direction. Furthermore, the axis along the +D1 direction is referred to as the D1 axis, the axis along the +D2 direction is referred to as the D2 axis, and the axis along the +D3 direction is referred to as the D3 axis.

[0010] [Light source configuration] The light source 31 emits illumination light WL in the +D1 direction. The light source 31 may be configured to include a solid-state light-emitting element and a wavelength conversion element that converts the wavelength of the light emitted from the solid-state light-emitting element. Alternatively, the light source 31 may be configured to include a discharge lamp such as an ultra-high pressure mercury lamp.

[0011] [Color separation device configuration] The color separator 32 separates the illumination light WL incident from the light source 31 into three color lights: blue light LB, green light LG, and red light LR. The color separator 32 includes dichroic mirrors 321 and 322, total reflection mirrors 323, 324, and 325, and relay lenses 326 and 327. The dichroic mirror 321 transmits blue light LB of the illumination light WL incident from the light source 31 in the +D1 direction, and reflects green light LG and red light LR in the +D3 direction. Dichroic mirror 322 reflects green light LG in the +D1 direction and transmits red light LR in the +D3 direction out of the green light LG and red light LR separated by dichroic mirror 321. The green light LG reflected by dichroic mirror 322 enters green light modulation device 34G via field lens 331 provided in image forming device 33.

[0012] Total reflection mirror 323 reflects in the +D3 direction blue light LB that has passed through dichroic mirror 321. Blue light LB reflected by total reflection mirror 323 passes through field lens 331 included in image forming device 33 and enters blue light modulation device 34B. Total reflection mirror 324 reflects the red light LR transmitted through dichroic mirror 322 in the +D1 direction. Total reflection mirror 325 reflects the red light LR reflected by total reflection mirror 324 in the −D3 direction. The red light LR reflected by total reflection mirror 325 enters red light modulation device 34R via field lens 331 provided in image forming device 33.

[0013] The relay lens 326 is disposed in the optical path of the red light LR between the dichroic mirror 322 and the total reflection mirror 324, and the relay lens 327 is disposed in the optical path of the red light LR between the total reflection mirror 324 and the total reflection mirror 325. The relay lenses 326 and 327 compensate for optical loss of the red light LR due to the optical path of the red light LR being longer than the optical paths of the blue light LB and the green light LG.

[0014] [Configuration of image forming device] The image forming device 33 individually modulates the incident blue light LB, green light LG, and red light LR, and combines the modulated colored lights LB, LG, and LR to form image light PL that is projected by the projection optical device 37. The image forming device 33 includes a field lens 331, an incident-side polarizing plate 332, an exit-side polarizing plate 333, a light modulation device 34, a light combining element 35, and a light path changing element 36.

[0015] [Field lens configuration] Field lens 331 collimates incident light. As shown in FIG. 1, image forming device 33 includes three field lenses 331. The three field lenses 331 include field lens 331B provided in the optical path of blue light LB, field lens 331G provided in the optical path of green light LG, and field lens 331R provided in the optical path of red light LR. The colored light LB, LG, and LR that pass through field lenses 331R, 331G, and 331B are incident on incident-side polarizing plates 332 provided according to the colored light. The incident-side polarizing plate 332 is disposed on the light incident side of the corresponding light modulation device 34. That is, the incident-side polarizing plate 332 is disposed between the field lens 331 and the light modulation device 34 in the optical path of the corresponding color light. The output polarizer 333 is disposed on the light output side of the corresponding light modulator 34. That is, the output polarizer 333 is disposed between the field lens 331 and the light combining element 35 in the optical path of the corresponding color light.

[0016] [Configuration of optical modulation device] FIG. 2 is a perspective view showing a part of the image forming device 33 as seen from the incident side of the green light LG. The light modulation devices 34 modulate the incident color light to form image light according to image information, and emit the formed image light to the light combining element 35. As shown in Figures 1 and 2, the image forming device 33 includes three light modulation devices 34. The three light modulation devices 34 include a blue light modulation device 34B that modulates blue light LB to emit blue image light, a green light modulation device 34G that modulates green light LG to emit green image light, and a red light modulation device 34R that modulates red light LR to emit red image light.

[0017] Each of the light modulation devices 34B, 34G, and 34R has a panel module 4, which will be described in detail later. Specifically, the blue light modulation device 34B has a blue panel module 4B that modulates blue light LB. The blue light LB modulated by the blue panel module 4B is emitted in the +D3 direction with a first axis Ax1 along the D3 axis as its optical axis, and enters the light combining element 35 via an output-side polarizing plate 333 for blue light LB. The green light modulation device 34G has a green panel module 4G that modulates the green light LG. The green light LG modulated by the green panel module 4G is emitted in the +D1 direction with a second axis Ax2 along the D1 axis as its optical axis, and enters the light combining element 35 via an output-side polarizing plate 333 for the green light LG. The red light modulation device 34R has a red panel module 4R that modulates red light LR. The red light LR modulated by the red panel module 4R is emitted in the −D3 direction with the first axis Ax1 as its optical axis, and enters the light combining element 35 via an output-side polarizing plate 333 for red light LR. The configuration of the panel module 4 will be described in detail later.

[0018] [Configuration of photosynthetic element] The light combining element 35 combines the blue light LB incident from the blue light modulation device 34B, the green light LG incident from the green light modulation device 34G, and the red light LR incident from the red light modulation device 34R to form image light PL, and outputs the combined light toward the optical path changing element 36. That is, the light combining element 35 outputs the formed image light PL toward the projection optical device 37. The light combining element 35 is configured by a substantially rectangular parallelepiped cross dichroic prism. As shown in Fig. 1, the light combining element 35 has a blue incident surface 35B, a green incident surface 35G, a red incident surface 35R, and an exit surface 35S. The blue incident surface 35B faces in the -D3 direction and is an incident surface onto which blue light is incident. The green incident surface 35G faces in the -D1 direction and is an incident surface onto which green light is incident. The red incident surface 35R faces in the +D3 direction and is an incident surface onto which red light is incident. The red incident surface 35R is the surface of the light combining element 35 opposite to the blue incident surface 35B. The exit surface 35S faces the +D1 direction and emits the image light PL with the second axis Ax2 as its optical axis. The exit surface 35S is the surface of the light combining element 35 opposite to the green entrance surface 35G.

[0019] [Schematic configuration of the optical path changing element] FIG. 3 is a perspective view showing a part of the image forming device 33 as seen from the emission side of the image light PL. 1 to 3, the optical path changing element 36 is disposed on the light output side of the image light PL with respect to the light combining element 35, and is disposed in the optical path of the image light PL between the light combining element 35 and the projection optical device 37. The optical path changing element 36 shifts the optical path of the image light PL incident from the light combining element 35, thereby increasing the resolution of the projection image displayed by the image light PL projected onto the projection surface PS. The configuration and operation of the optical path changing element 36 will be described in detail later.

[0020] [Configuration of the projection optical device] The projection optical device 37 projects the image light PL incident from the light combining element 35 onto the projection surface PS via the optical path changing element 36. Although not shown in the figures, the projection optical device 37 can be exemplified by a lens assembly having a plurality of lenses and a lens barrel that holds the plurality of lenses.

[0021] [Panel module configuration] Fig. 4 is a perspective view showing the panel module 4 as seen from the light incident side, Fig. 5 is a perspective view showing the panel module 4 as seen from the light exit side, Fig. 6 is an exploded perspective view showing the panel module 4 as seen from the light incident side, and Fig. 7 is an exploded perspective view showing the panel module 4 as seen from the light exit side. As shown in FIGS. 4 to 7, the panel module 4 includes a liquid crystal panel 41, a holding frame 44, and a temperature control unit 45.

[0022] In the following description, three mutually orthogonal directions are referred to as the +X direction, the +Y direction, and the +Z direction. In this embodiment, the +Z direction is the traveling direction of light incident on the panel module 4. The left direction when the panel module 4 is viewed along the +Z direction so that the +Y direction coincides with the upward direction is referred to as the +X direction. Although not shown in the figures, the direction opposite the +X direction is referred to as the -X direction, the direction opposite the +Y direction is referred to as the -Y direction, and the direction opposite the +Z direction is referred to as the -Z direction. In other words, the +Z direction relative to the panel module 4 is the light emission side relative to the panel module 4, and the -Z direction relative to the panel module 4 is the light incidence side relative to the panel module 4. Also, the axis along the +X or -X direction is defined as the X axis, the axis along the +Y or -Y direction is defined as the Y axis, and the axis along the +Z or -Z direction is defined as the Z axis. Note that the long side of a modulation area PA (described later) is aligned with the X axis, and the short side of the modulation area PA is aligned with the Y axis. In the blue panel module 4B, the +Z direction is the +D3 direction, and the +X direction is the -D1 direction. In the green panel module 4G, the +Z direction is the +D1 direction, and the +X direction is the +D3 direction. In the red panel module 4R, the +Z direction is the -D3 direction, and the +X direction is the +D1 direction. Furthermore, in each of the panel modules 4B, 4G, and 4R, the +Y direction is the +D2 direction.

[0023] [LCD panel configuration] FIG. 8 is a diagram showing a cross section of the panel module 4 along the YZ plane. The liquid crystal panel 41 is a transmissive liquid crystal panel that modulates incident color light and emits the modulated color light as image light in the traveling direction of the incident color light. As shown in FIGS. 4 to 8, the liquid crystal panel 41 includes a panel body 42 and an FPC (Flexible Printed Circuits) 43. The panel body 42 modulates incident light as it passes through the interior thereof. The panel body 42 includes an optical action portion 421, and an incident-side dustproof substrate 425 and an exit-side dustproof substrate 426 that sandwich the optical action portion 421 along the Z axis.

[0024] As shown in FIG. 8, the optical action section 421 has a liquid crystal layer 422, and an incident-side substrate 423 and an exit-side substrate 424 that sandwich the liquid crystal layer 422 along the Z axis. The liquid crystal layer 422 is formed by liquid crystal molecules sealed between an incident side substrate 423 and an exit side substrate 424 . The incident-side substrate 423 is disposed on the light incident side with respect to the liquid crystal layer 422. The incident-side substrate 423 has a counter electrode provided on the surface facing the liquid crystal layer 422. The emission-side substrate 424 is disposed on the light emission side of the liquid crystal layer 422. The emission-side substrate 424 has a plurality of pixel electrodes provided on the surface facing the liquid crystal layer 422. The emission-side substrate 424 can be configured, for example, by a TFT (Thin Film Transistor) substrate. When viewed from the -Z direction, which is the light incident side, or the +Z direction, which is the light exit side, the region in which multiple pixel electrodes are arranged in the optical action section 421 is a modulation region PA that modulates incident light, and one pixel is formed by the region in which each pixel electrode is arranged in the modulation region PA. When viewed from the light incident side, the modulation region PA is formed in a rectangular shape, with two long sides along the +X direction and two short sides along the +Y direction that intersect with the long sides. In this embodiment, the aspect ratio of the modulation region PA is 16:9, but it may also be, for example, 4:3. The incident-side substrate 423 and the exit-side substrate 424 are connected to the FPC 43, and change the alignment state of the liquid crystal molecules forming the liquid crystal layer 422 in response to an image signal supplied from the FPC 43. This causes the modulation area PA of the optical action section 421 to modulate the incident light. Note that the incident-side substrate 423 may be a TFT substrate, and the exit-side substrate 424 may be a counter substrate having a counter electrode.

[0025] The incident-side dustproof substrate 425 is a light-transmitting substrate provided on the light incident surface of the incident-side substrate 423 so as to be capable of transferring heat, and is made of, for example, sapphire glass. The incident-side dustproof substrate 425 prevents dust and other particles from adhering to the light incident surface of the incident-side substrate 423 and casting a shadow of the dust and other particles on the image light, and also radiates heat from the liquid crystal layer 422 transferred from the incident-side substrate 423 to the outside of the liquid crystal panel 41. When the liquid crystal panel 41 is viewed from the -Z direction, the incident-side dustproof substrate 425 covers the modulation area PA. More specifically, the incident-side dustproof substrate 425 covers the entire light incident surface of the incident-side substrate 423 when viewed from the light incident side of the optical modulator 34. That is, the planar size of the incident-side dustproof substrate 425 when viewed from the light incident side of the optical modulator 34 is larger than the planar size of the incident-side substrate 423 when viewed from the light incident side of the optical modulator 34. In other words, the area of ​​the incident-side dustproof substrate 425 when viewed from the light incident side of the optical modulator 34 is larger than the area of ​​the incident-side substrate 423 when viewed from the light incident side of the optical modulator 34. More specifically, the dimension of the incident-side dustproof substrate 425 along the +X direction is equal to or larger than the dimension of the incident-side substrate 423 along the +X direction, and the dimension of the incident-side dustproof substrate 425 along the +Y direction is equal to or larger than the dimension of the incident-side substrate 423 along the +Y direction. However, this is not limited to the above, and one of the dimensions of the incident-side dustproof substrate 425 along the +X direction and the dimension of the incident-side dustproof substrate 425 along the +Y direction may be larger than the dimension of the incident-side substrate 423 in the same direction, and the other dimension may be smaller than the dimension of the incident-side substrate 423 in the same direction.

[0026] A heat-transfer frame 46 (described later) of the temperature control unit 45 is connected to the incident-side dustproof substrate 425 in a heat-transferable manner, and heat is exchanged between the incident-side dustproof substrate 425 and the heat-transfer frame 46. When the temperature of the incident-side dustproof substrate 425 is higher than the temperature of the heat-transfer frame 46, heat is transferred from the incident-side dustproof substrate 425 to the heat-transfer frame 46, and when the temperature of the heat-transfer frame 46 is higher than the temperature of the incident-side dustproof substrate 425, heat is transferred from the heat-transfer frame 46 to the incident-side dustproof substrate 425. The thermal conductivity of the incident-side dustproof substrate 425 is equal to or higher than the thermal conductivity of the incident-side substrate 423. However, the present invention is not limited to this, and the thermal conductivity of the incident-side dustproof substrate 425 may be equal to or lower than the thermal conductivity of the incident-side substrate 423.

[0027] The exit-side dustproof substrate 426 is a light-transmitting substrate provided on the light exit surface of the exit-side substrate 424, and is made of, for example, sapphire glass. The exit-side dustproof substrate 426 prevents dust and other particles from directly adhering to the light exit surface of the exit-side substrate 424 and casting a shadow of the dust and other particles on the image light, and also dissipates heat from the liquid crystal layer 422 transferred from the exit-side substrate 424 to the outside of the liquid crystal panel 41. When the liquid crystal panel 41 is viewed from the +Z direction, the exit-side dustproof substrate 426 is provided on the light exit surface of the exit-side substrate 424 so as to be heat-transferable and to cover at least the modulation area PA. The thermal conductivity of the output-side dustproof substrate 426 is equal to or higher than the thermal conductivity of the output-side substrate 424. However, the thermal conductivity of the output-side dustproof substrate 426 is not limited to this, and may be equal to or lower than the thermal conductivity of the output-side substrate 424.

[0028] 4 to 8, the FPC 43 extends in the +Y direction from the incident-side substrate 423 and the exit-side substrate 424, and is connected to the control device 7. The FPC 43 has a driver circuit 431 that drives the optical action unit 421, and the driver circuit 431 outputs a drive signal to the exit-side substrate 424 in accordance with an image signal input from the control device 7.

[0029] [Support frame configuration] The holding frame 44 holds the panel body 42 and the FPC 43. More specifically, the holding frame 44 is combined with a heat transfer frame 46 of the temperature control unit 45 to house the liquid crystal layer 422, the incident-side substrate 423, the exit-side substrate 424, the incident-side dustproof substrate 425, and the exit-side dustproof substrate 426. In other words, the holding frame 44 is separate from the heat transfer frame 46. As shown in FIGS. 5 and 7, the holding frame 44 is formed in a rectangular shape that is long in the Y-axis direction when viewed from the light exit side. As shown in FIG. 6, the holding frame 44 has a recess 441, an opening 442, and a through hole 443.

[0030] The recess 441 is a portion recessed in the +Z direction in the holding frame 44. When the holding frame 44 and the heat-transfer frame 46 are combined, the recess 441 forms an accommodation space that accommodates the exit-side substrate 424 and the exit-side dustproof substrate 426 of the liquid crystal panel 41. The opening 442 is located at the bottom of the recess 441 and passes through the holding frame 44 along the Z axis, and the exit-side dustproof substrate 426 is disposed inside the opening 442. Light emitted from the panel body 42 passes through the opening 442 and is emitted to the outside of the liquid crystal panel 41.

[0031] FIG. 9 is a perspective view showing a part of the image forming device 33 in a state where the light modulation device 34 is separated from the support member SM fixed to the light combining element 35. The through holes 443 penetrate the holding frame 44 along the Z axis. The through holes 443 are provided at each of the four corners of the rectangular holding frame 44 when viewed from the +Z direction, which is the light emission side. That is, the holding frame 44 has four through holes 443. As shown in FIG. 9 , arm portions SM1 of a support member SM provided on the light combining element 35 are inserted into each of the four through holes 443. Here, the support members SM are provided on the blue incident surface 35B, the green incident surface 35G, and the red incident surface 35R of the light combining element 35, respectively, while holding the corresponding output-side polarizers 333. With the arm portions SM1 of each support member SM inserted into the four through holes 443 of the holding frame 44 of each light modulation device 34, the arm portions SM1 are joined to the inner surfaces of the through holes 443 with an adhesive such as an ultraviolet-curing adhesive, thereby integrating the light combining element 35 and the three light modulation devices 34B, 34G, and 34R. The support member SM has an opening that is closed by the exit-side polarizing plate 333, and the colored light that has passed through the exit-side polarizing plate passes through the opening and enters the light combining element .

[0032] [Temperature control unit configuration] The temperature control unit 45 adjusts the temperature of the panel body 42. More specifically, the temperature control unit 45 transfers heat between the incident-side dustproof substrate 425 and adjusts the temperature of the liquid crystal layer 422 via the incident-side substrate 423. The temperature control unit 45 has a heat-transfer frame 46, a heating element 47, and a cover member 48.

[0033] [Heat transfer frame configuration] The heat transfer frame 46 is formed in a shape that is elongated in the +Y direction when viewed from the light incident side. The heat transfer frame 46 is combined with the holding frame 44 by a cover member 48, and in addition to housing the panel main body 42, it also supports the heating element 47. As shown in FIG. 6, the heat transfer frame 46 has an opening 461, an arrangement portion 463, an air guide portion 464, and a heat dissipation portion 465, and as shown in FIG. 7, it also has a contact portion 462. The heat transfer frame 46 also has a surface 46A facing the light output side and a surface 46B facing the light incident side and opposite to surface 46A. Surface 46B corresponds to the first surface.

[0034] The opening 461 is formed in approximately the center of the heat transfer frame 46 in the +Y direction, and penetrates the heat transfer frame 46 along the Z axis. The opening 461 is provided in a rectangular shape corresponding to the modulation area PA, and allows color light incident on the entrance-side dustproof substrate 425 to pass through.

[0035] As shown in FIG. 7, the contact portion 462 is a portion of the heat-transfer frame 46 that faces the light-emitting side and faces the incident-side dustproof substrate 425. More specifically, the contact portion 462 is a peripheral portion of the opening 461 on the surface 46A. The contact portion 462 contacts a peripheral portion of the light incident surface 425A shown in FIG. 6 of the incident-side dustproof substrate 425 when viewed from the light incident side. The portion that the contact portion 462 contacts is a portion of the light incident surface 425A through which light that is incident to the modulation area PA does not pass. In other words, the contact portion 462 contacts a rectangular frame-shaped portion of the light incident surface 425A that is outside the modulation area PA when viewed from the light incident side and that surrounds the modulation area PA.

[0036] The placement portion 463 is a portion where the heating element 47 is placed, and is provided on the surface 46B. The arrangement portion 463 is provided on the surface 46B at the periphery of the opening 461. That is, the arrangement portion 463 is a rectangular frame-shaped portion that surrounds the opening 461 on the surface 46B. The arrangement section 463 is a recess recessed from the surface 46B toward the entrance-side dustproof board 425 in the +Z direction. Therefore, the arrangement section 463 is configured to be thinner than the portion of the heat-transfer frame 46 excluding the airflow guide section 464. In other words, the dimension of the arrangement section 463 in the +Z direction is smaller than the dimension of the portion of the heat-transfer frame 46 excluding the airflow guide section 464 in the +Z direction. This makes it easier for heat from the heating element 47 arranged in the arrangement section 463 to be transferred to the entrance-side dustproof board 425 via the contact section 462 provided on the surface 46A opposite to the surface 46B on which the arrangement section 463 is located.

[0037] The airflow guide section 464 is provided at the end of the heat transfer frame 46 in the -Y direction. The airflow guide section 464 guides the cooling air circulated in the +Y direction by the cooling device 6, which will be described later, to the incident-side dustproof board 425 exposed within the opening 461. In other words, the airflow guide section 464 is provided on the heat transfer frame 46 upstream of the opening 461 in the direction of the cooling air, and guides the cooling air to the incident-side dustproof board 425. The cooling air that has circulated along the incident-side dustproof board 425 flows to the heat dissipation section 465. The surface of airflow guidance section 464 facing the -Z direction is airflow guidance surface 464A that guides the cooling air. The intersection angle between airflow guidance surface 464A and surface 46B and the length of airflow guidance surface 464A along the +Y direction will be described in detail later.

[0038] Heat dissipation section 465 is provided on surface 46B on the opposite side of opening 461 to airflow guidance section 464. That is, heat dissipation section 465 is provided at the end of heat transfer frame 46 in the +Y direction. Heat dissipation section 465 has a configuration in which a plurality of fins extending along the YZ plane are lined up along the X axis. That is, heat dissipation section 465 has a plurality of fins lined up along the X axis. Heat dissipation section 465 dissipates the heat transferred to heat transfer frame 46 to the cooling air flowing in the +Y direction. As a result, heat transferred from liquid crystal layer 422 via incident-side dustproof substrate 425 is dissipated to the cooling air.

[0039] [Heating element configuration] The heating element 47 generates heat to heat the liquid crystal layer 422 under the control of the control device 7, which will be described later. The heating element 47 is formed in a rectangular frame shape having a rectangular passage opening 471 corresponding to the opening 461 of the heat-transfer frame 46, and is disposed in the arrangement portion 463 of the heat-transfer frame 46. That is, the heat generated by the heating element 47 is transferred from the contact portion 462 via the arrangement portion 463 of the heat-transfer frame 46 to the incident-side dustproof substrate 425, and ultimately heats the liquid crystal layer 422 via the incident-side substrate 423. The passage opening 471 is an opening through which light incident on the incident-side dustproof substrate 425 passes. Although detailed illustration is omitted, the heating element 47 according to this embodiment is a heater having fine wiring provided on a flexible printed circuit board, and the wiring is connected to a pair of electrode portions 472, 473 extending in the +Y direction. When a current is passed through the pair of electrode portions 472, 473, the wiring portions become a resistor, causing the heating element 47 to generate heat. Note that the heating element 47 is not limited to such a heater, and may be a thermoelectric conversion element such as a Peltier element.

[0040] [Cover material configuration] The cover member 48 is provided on the opposite side of the heat generating element 47 from the heat transfer frame 46, covers at least a portion of the heat generating element 47, and is fixed to the holding frame 44. In other words, the cover member 48 is disposed on the side closest to the light incident side of the panel module 4, and fixes the heat transfer frame 46 and the heat generating element 47 to the holding frame 44. The cover member 48 has a cover portion 481 and a locking portion 484. The cover portion 481 is a rectangular frame-shaped portion that covers the heating element 47 arranged in the arrangement portion 463 in the -Z direction. In this embodiment, the cover portion 481 covers the entire surface of the heating element 47 when viewed from the light incident side. The cover portion 481 has an opening portion 482 that is provided in accordance with the passage opening 471 of the heating element 47. The opening portion 482 passes light that is incident on the modulation area PA. An absorption layer 483 that absorbs visible light is provided on the light incident surface 481A of the opening 482. The absorption layer 483 absorbs marginal light that does not enter the modulation area PA out of the light that enters the light modulation device 34. Therefore, when light enters the light modulation device 34, the cover member 48 absorbs the marginal light and generates heat. This heat is used to warm the liquid crystal layer 422. The locking portions 484 extend in the +Z direction from the +X direction end and the -X direction end of the cover portion 481. The locking portions 484 lock the holding frame 44 when the cover member 48 is attached to the holding frame 44. This fixes the heat transfer frame 46 and the heating element 47 to the holding frame 44.

[0041] [Assembly of panel module 4] In this embodiment, the panel module 4 is assembled as follows. First, the panel main body 42 is placed on the holding frame 44. At this time, the output-side substrate 424 is positioned in the recess 441 so that the output-side dustproof substrate 426 is placed in the opening 442 of the holding frame 44. Thereafter, the heat-transfer frame 46 is placed so as to cover the panel main body 42. At this time, the input-side dustproof substrate 425 is placed in the opening 461, and the heat-transfer frame 46 is placed so that the contact portion 462 comes into contact with the input-side dustproof substrate 425. Then, the heating element 47 is placed in the placement portion 463 of the heat transfer frame 46 , and the cover member 48 is fixed to the holding frame 44 so that the heat transfer frame 46 is sandwiched between the cover portion 481 of the cover member 48 and the holding frame 44 . In this way, the panel module 4 is assembled.

[0042] [Configuration of optical path changing element] FIG. 10 is a diagram showing the optical path changing element 36 as viewed from the light exit side. As described above, the optical path changing element 36 shifts the optical path of the image light PL incident from the light combining element 35, thereby increasing the resolution of the projected image displayed on the projection surface PS. As shown in FIG. 10, the optical path changing element 36 includes an optical member 361, a first holding member 362, a second holding member 363, a base 364, a first actuator 365, and a second actuator 366.

[0043] In addition to the arrows indicating the +D1 direction, the +D2 direction, and the +D3 direction, Figure 10 also shows the +X direction, the +Y direction, and the +Z direction of the blue light modulation device 34B, which is positioned closer to the optical path changing element 36 than the green light modulation device 34G. 10, the +D1 direction is perpendicular to the paper surface and points away from the paper surface, the +D2 direction is leftward, and the +D3 direction is upward. Of the +X, +Y, and +Z directions in the blue light modulation device 34B, the +X direction is the same as the -D1 direction, the +Y direction is the same as the +D3 direction, and the +Z direction is the same as the +D3 direction.

[0044] [Optical component configuration] The optical member 361 is a light-transmitting substrate such as glass, and is an optical path changing member. The optical member 361 is disposed in the optical path between the light combining element 35 and the projection optical device 37, and the image light PL is incident on the optical member 361 from the light combining element 35. When the actuators 365 and 366 are operated, the optical member 361 is tilted with respect to a virtual plane perpendicular to the emission optical axis of the image light PL from the light combining element 35, and the optical path of the image light PL is shifted by refraction.

[0045] [Configuration of first holding member] The first holding member 362 is formed in a rectangular frame shape, holds the optical member 361, and is held by the second holding member 363 so as to be swingable about the first oscillation axis Rx1. The first holding member 362 has a frame portion 3621, shaft portions 3622 and 3623, and fixing portions 3624 and 3625. The frame portion 3621 surrounds and supports the optical member 361. The frame portion 3621 has an opening (not shown) through which light passes to pass through the optical member 361. A first magnet 3651 of the first actuator 365 is fixed to the periphery of the frame portion 3621 facing the +D2 direction. The shaft portion 3622 protrudes from the outer periphery of the frame portion 3621 in the +D3 direction, and the shaft portion 3623 protrudes from the outer periphery of the frame portion 3621 in the -D3 direction. The fixed portion 3624 is provided at the tip of the shaft portion 3622, and the fixed portion 3625 is provided at the tip of the shaft portion 3623. By fixing the fixed portions 3624 and 3625 to the second holding member 363, the first holding member 362 is supported so as to be able to swing about a first oscillation axis Rx1 along the +D3 direction. The first oscillation axis Rx1 coincides with an extension line of the central axes of the shaft portions 3622 and 3623.

[0046] [Configuration of second holding member] The second holding member 363 holds the first holding member 362 so as to be swingable about the first oscillation axis Rx1, and also holds the first coil 3652 of the first actuator 365. The second holding member 363 has a frame portion 3631, an opening 3632, shaft portions 3633 and 3634, fixed portions 3635 and 3636, and support portions 3637, 3638, and 3639. The frame portion 3631 is formed in a frame shape, and an opening portion 3632 is provided in the center of the frame portion 3631 when viewed from the light emission side. The opening 3632 penetrates the frame portion 3631 along the +X direction. The frame portion 3621 of the first holding member 362 is disposed inside the opening 3632.

[0047] The shaft portion 3633 protrudes from the outer periphery of the frame portion 3631 in the +D2 direction, and the shaft portion 3634 protrudes from the outer periphery of the frame portion 3631 in the -D2 direction. The fixed portion 3635 is provided at the tip of the shaft portion 3633, and the fixed portion 3636 is provided at the tip of the shaft portion 3634. By fixing the fixed portions 3635 and 3636 to the base 364, the second holding member 363 is supported so as to be able to swing about a second oscillation axis Rx2 along the +D2 direction. The second oscillation axis Rx2 coincides with an extension line of the central axes of the shaft portions 3633 and 3634.

[0048] The support portion 3637 is provided on the inner edge of the opening 3632 in the +D2 direction. The support portion 3637 supports the first coil 3652 of the first actuator 365. The support portion 3638 is provided at the end of the frame portion 3631 facing the +D2 direction and the +D3 direction. The support portion 3638 supports the second magnet 3661 of the second actuator 366. The support portion 3639 is provided at the end of the frame portion 3631 facing the +D2 direction and the -D3 direction. The support portion 3639 supports the second magnet 3663 of the second actuator 366. The support portions 3638 and 3639 are provided at positions sandwiching the support portion 3637 on the D3 axis.

[0049] [Base configuration] The base 364 holds the second holding member 363 so that it can swing about the second oscillation axis Rx2, and also holds the second coils 3662 and 3664 of the second actuator 366. The base 364 is formed in a frame shape and has an opening 3641 in which the second holding member 363 is disposed. In addition, as shown in FIG. 2, the base 364 has a pedestal portion 3642 that supports the light combining element 35, which is made up of a cross dichroic prism, from the −D2 direction.

[0050] [Configuration of the first actuator] The first actuator 365 swings the first holding member 362 around a first oscillation axis Rx1 along the D3 axis, thereby swinging the optical member 361 around the first oscillation axis Rx1. The first actuator 365 has a first magnet 3651 and a first coil 3652 that are positioned on the second oscillation axis Rx2 and in the +D2 direction with respect to the first oscillation axis Rx1. That is, the first actuator 365 is a voice coil motor that has the first magnet 3651 fixed to the first holding member 362 and the first coil 3652 fixed to the second holding member 363. The control device 7, which will be described later, supplies an alternating current to the first coil 3652, causing the optical member 361 held by the first holding member 362 to oscillate about the first oscillation axis Rx1.

[0051] [Configuration of the second actuator] The second actuator 366 swings the second holding member 363, thereby swinging the optical member 361 around a second swing axis Rx2 along the D2 axis. The second actuator 366 is disposed in the +D2 direction with respect to the first oscillation axis Rx1, and includes a first drive unit 366A and a second drive unit 366B that are disposed line-symmetrically with respect to the second oscillation axis Rx2. That is, the first drive unit 366A and the second drive unit 366B are disposed on either side of the second oscillation axis Rx2, and the second actuator 366 is disposed in the +D2 direction with respect to the first oscillation axis Rx1. The +D2 direction is along the short side of the modulation area PA of each panel module 4B, 4G, 4R.

[0052] The first driving section 366A is disposed in the +D3 direction relative to the second oscillation axis Rx2, and the second driving section 366B is disposed in the -D3 direction relative to the second oscillation axis Rx2. The first driving unit 366A is a voice coil motor having a second magnet 3661 fixed to the second holding member 363 and a second coil 3662 supported by the base 364. The second driving unit 366B is a voice coil motor having a second magnet 3663 fixed to the second holding member 363 and a second coil 3664 supported by the base 364. The second coil 3662 is fixed to the base 364 together with a substrate BD1 that supplies current to the second coil 3662, and the second coil 3664 is fixed to the base 364 together with a substrate BD2 that supplies current to the second coil 3664. The control device 7, which will be described later, supplies AC currents of opposite phases to the second coils 3662 and 3664 via the substrates BD1 and BD2, causing the second holding member 363 to oscillate about the second oscillation axis Rx2 relative to the base 364. This causes the optical member 361 to oscillate about the second oscillation axis Rx2.

[0053] [Optical path shift by optical path changing element] FIG. 11 is a diagram illustrating the shift of the optical path of the image light by the optical path changing element 36. In FIG. Here, the improvement in the resolution of the projected image by the optical path changing element 36 will be described. As described above, the optical path changing element 36 changes the attitude of the optical member 361 through which the image light PL passes, thereby utilizing refraction at the optical member 361 to shift the optical path of the image light PL. 11 are directions that are perpendicular to each other on the projection surface PS, the -F1 direction is the opposite direction to the +F1 direction, and the -F2 direction is the opposite direction to the +F2 direction. The +F1 direction corresponds to the first direction, and the -F2 direction corresponds to the second direction.

[0054] Specifically, the optical path changing element 36 swings the optical member 361 in two directions, a first swing direction around the first swing axis Rx1 and a second swing direction around the second swing axis Rx2, thereby shifting the optical path of the image light PL in the ±F1 direction and the ±F2 direction, as shown in Fig. 11. As a result, the pixels Px of the projection image displayed on the projection surface PS are shifted in the ±F1 direction and the ±F2 direction.

[0055] The control device 7, which will be described later, uses the optical path changing element 36 to combine an optical path shift of the image light PL in the ±F1 direction with an optical path shift of the image light PL in the ±F2 direction, thereby increasing the apparent number of pixels and improving the resolution of the projected image. For example, the control device 7 shifts the optical path of the image light PL to move the pixel Px to a position shifted by half a pixel in each of the ±F1 direction and the ±F2 direction. Note that half a pixel refers to half the size of the pixel Px. As a result, the image display position on the projection surface PS shifts to a second position P2, which is shifted by half a pixel in the +F1 direction from the first position P1, a third position P3, which is shifted by half a pixel in the -F2 direction from the second position P2, and a fourth position P4, which is shifted by half a pixel in the -F2 direction from the first position P1. The second position P2, the third position P3, and the fourth position P4 correspond to shift positions from the first position P1.

[0056] The control device 7 then shifts the optical path of the image light PL using the optical path changing element 36 so that pixel Px is displayed at each of positions P1, P2, P3, and P4 for a fixed time, and changes the display content of each of the light modulation devices 34B, 34G, and 34R in synchronization with the optical path shift, thereby making it possible to display pixels A, B, C, and D that appear smaller than the size of pixel Px.

[0057] For example, if pixels A, B, C, and D are displayed at an overall frequency of 60 Hz, it is necessary to switch the display of each liquid crystal panel 41 at a speed four times 60 Hz, corresponding to positions P1, P2, P3, and P4. In this case, by setting the refresh rate of each liquid crystal panel 41 to 240 Hz and each liquid crystal panel 41 sequentially forming image light PL including pixel A displayed at the first position P1, image light PL including pixel B displayed at the second position P2, image light PL including pixel C displayed at the third position P3, and image light PL including pixel D displayed at the fourth position P4, it is possible to display a projected image with a high apparent resolution.

[0058] In the example of light path shift shown in FIG. 11, the ±F1 and ±F2 directions are the arrangement directions of pixels Px displayed in a matrix on the projection surface PS. However, the ±F1 and ±F2 directions do not have to be orthogonal to each other and may be inclined with respect to the arrangement direction of pixels Px. Even with such shift directions, the pixel Px can be moved to each of positions P1, P2, P3, and P4 by appropriately combining light path shifts in the ±F1 and ±F2 directions. Furthermore, the amount of displacement of each of positions P2 to P4 from the first position P1 is not limited to half a pixel and may be, for example, ¼ or ¾ of the size of pixel Px.

[0059] [Positional relationship between heating element and actuator] FIG. 12 is a diagram showing the positional relationship between the heating elements 47 of the optical modulation devices 34B and 34G and the actuators 365 and 366 of the optical path changing element 36, as viewed from the blue light incident side. FIG. 13 is a diagram showing the positional relationship between the heating elements 47 of the optical modulation devices 34R and 34G and the actuators 365 and 366, as viewed from the red light incident side. FIG. 14 is a diagram showing the positional relationship between the heating elements 47 of the optical modulation devices 34B, 34G, and 34R and the actuators 365 and 366, as viewed from the light output side of the optical path changing element 36. FIG. 12 shows arrows indicating the +D1 direction, +D2 direction, and +D3 direction, respectively, and arrows indicating the +X direction, +Y direction, and +Z direction, respectively, of the optical modulation device 34B. FIG. 13 shows arrows indicating the +D1 direction, +D2 direction, and +D3 direction, respectively, and arrows indicating the +X direction, +Y direction, and +Z direction, respectively, of the optical modulation device 34R.

[0060] For example, when the temperature of liquid crystal layer 422 is low, heating element 47 generates heat and warms liquid crystal layer 422. On the other hand, when the heat generated by heating element 47 is transmitted to magnets 3651, 3661, and 3663 of actuators 365 and 366, causing the temperatures of magnets 3651, 3661, and 3663 to rise, a phenomenon called demagnetization occurs in which the magnetic force of magnets 3651, 3661, and 3663 weakens. Therefore, in order to stably operate the first actuator 365 and the second actuator 366, it is necessary to separate the first magnet 3651 and the second magnets 3661 and 3663 from the heating element 47.

[0061] In this embodiment, as shown in FIGS. 12 to 14, the heating element 47 of the light modulation device 34B is disposed at a position away from the actuators 365 and 366 in the +D2 direction. Specifically, the heating element 47 of the light modulation device 34B is provided at a position surrounding the modulation area PA through which the blue light passes in the light modulation device 34B, and the actuators 365, 366 are arranged to be shifted in the +D2 direction with respect to the optical member 361 through which the image light PL passes in the light-path changing element 36. As described above, the +D2 direction is the direction along the short side of the modulation area PA of the light modulation device 34B. Therefore, the heating element 47 of the light modulation device 34B is arranged at a position spaced apart from the actuators 365, 366 in the -D2 direction.

[0062] Similarly, as shown in FIGS. 13 and 14, the heating element 47 of the optical modulation device 34R is disposed at a position away from the actuators 365 and 366 in the +D2 direction. Specifically, the heating element 47 of the light modulation device 34R is provided at a position surrounding the modulation area PA through which the red light passes in the light modulation device 34R, and the actuators 365 and 366 are disposed so as to be shifted in the +D2 direction with respect to the optical member 361 through which the image light PL passes in the optical path changing element 36. Therefore, the heating element 47 of the light modulation device 34B is disposed at a position away from the actuators 365 and 366 in the -D2 direction.

[0063] In this way, by arranging the heating element 47 of each optical modulation device 34B, 34R and each actuator 365, 366 at a distance in the +D2 direction, it is possible to prevent the thermal influence of the heating element 47 of each optical modulation device 34B, 34R on each magnet 3651, 3661, 3663. On the other hand, the heating element 47 of the optical modulation device 34G is disposed at a position not only away from the actuators 365, 366 in the -D2 direction, but also away from them in the -D1 direction. Since the light combining element 35 is disposed between the optical modulation device 34G and the optical path changing element 36 and the optical modulation device 34G and the optical path changing element 36 are disposed at a sufficient distance from each other, the heat generated by the heating element 47 of the optical modulation device 34G does not have a significant effect on the actuators 365, 366. Therefore, it is possible to prevent demagnetization of the first magnet 3651 and the second magnets 3661 and 3663, and to prevent the operation of the optical path changing element 36 from being hindered by heat.

[0064] [Cooling system configuration] FIG. 15 is a perspective view showing a part of the image forming apparatus 33 and the cooling device 6. As shown in FIG. The cooling device 6 cools the objects to be cooled that constitute the projector 1. As shown in Fig. 15 , the cooling device 6 has a configuration for cooling the image forming device 33, which is one of the objects to be cooled. Specifically, the cooling device 6 has fans 61 and 62 and a duct 63. The fans 61 and 62 blow cooling gas to generate cooling air that cools the image forming device 33. In this embodiment, the fans 61 and 62 are centrifugal fans, but they may also be axial fans. In the example of FIG. 15 , the fan 61 is larger than the fan 62, and the amount of air blown by the fan 61 is greater than the amount of air blown by the fan 62.

[0065] FIG. 16 is an exploded perspective view showing the cooling device 6 in a state where the first duct portion 64 and the second duct portion 65 are separated. The duct 63 has a first introduction section 631 that introduces the cooling air blown out from the fan 61 into its interior, and a second introduction section 632 that introduces the cooling air blown out from the fan 62 into its interior. The duct 63 guides the cooling air introduced into its interior from the fans 61 and 62 to the optical modulation devices 34B, 34G, and 34R and other objects to be cooled. As shown in FIG. 16 , the duct 63 is configured by combining a first duct section 64 and a second duct section 65.

[0066] The first duct portion 64 is disposed in the +D2 direction relative to the second duct portion 65. The first duct portion 64 has four air outlets 64B, 64G, 64R, and 64P that penetrate the first duct portion 64 along the +D2 direction. The air outlet 64B is provided corresponding to the optical modulation device 34B. The air outlet 64B sends out the cooling air that has circulated inside the duct 63 in the +D2 direction toward the optical modulation device 34B. The air outlet 64G is provided corresponding to the optical modulation device 34G. The air outlet 64G sends out the cooling air that has circulated inside the duct 63 in the +D2 direction toward the optical modulation device 34G. The air outlet 64R is provided corresponding to the optical modulation device 34R. The air outlet 64R sends out the cooling air that has circulated inside the duct 63 in the +D2 direction toward the optical modulation device 34R. The outlet 64P is provided corresponding to the other cooling target. The outlet 64P sends out the cooling air that has circulated through the duct 63 in the +D2 direction toward the other cooling target. Note that the other cooling target may be an optical component that constitutes the image projection device 3. An example of such an optical component is a polarization conversion element (not shown in FIG. 1). The polarization conversion element separates p-polarized and s-polarized components from incident light and converts one of the separated p-polarized and s-polarized components into the other polarized component, thereby aligning the polarized components of the incident light into a single type of polarized component.

[0067] The second duct portion 65 is disposed on the opposite side of the first duct portion 64 from the image forming device 33, and is combined with the first duct portion 64. The second duct portion 65 has a first branch portion 651 and a second branch portion 652. The first dividing section 651 divides the first cooling air sent out from the fan 61 into two. One of the first cooling air flows to the optical modulation device 34B through the outlet 64B, and the other first cooling air flows to the optical modulation device 34G through the outlet 64G. The second dividing section 652 divides the second cooling airflow sent out from the fan 62 into two. One of the second cooling airflows flows to the optical modulation device 34R via the outlet 64R, and the other second cooling airflow flows to the other cooling target via the outlet 64P. The cooling air flows in the +D2 direction along the optical modulation devices 34B, 34G, and 34R through the duct 63. In other words, the cooling air sent out from the duct 63 flows in the +Y direction along the optical modulation devices 34B, 34G, and 34R.

[0068] [Detailed configuration of the airflow guidance section] FIG. 17 is a diagram showing a cross section of the heat transfer frame 46 and the incident-side dustproof substrate 425 along the YZ plane. As described above, the heat transfer frame 46 has the air guide section 464 located in the −Y direction with respect to the opening 461, and the cooling air flowing in the +Y direction is guided by the air guide section 464 to the entrance-side dustproof substrate 425 inside the opening 461. Here, in order for the air guide section 464 to properly guide the cooling air into the opening 461 while also miniaturizing the heat transfer frame 46, it is necessary to appropriately set the intersection angle between the air guide surface 464A and the extension plane of the surface 46B of the heat transfer frame 46, and the dimension of the air guide surface 464A along the +Y direction.

[0069] In contrast to this, in this embodiment, the heat transfer frame 46 including the airflow guidance section 464 is configured so as to satisfy the following formula 1. In the following formula 1, L represents the dimension of the wind guiding surface 464A in the +Y direction, and is expressed in units of mm (millimeters). θ represents the intersection angle between the wind guiding surface 464A and the extension plane of surface 46B, and is expressed in units of degrees. x represents the dimension of the opening 461 in the +Y direction, and is expressed in units of mm (millimeters). v is the dynamic viscosity coefficient of air. U represents the wind speed of the airflow flowing in the +Y direction, and is expressed in units of m / s. The +Y direction corresponds to the wind guiding direction along wind guiding surface 464A toward opening 461, and surface 46B corresponds to the first surface. L×tanθ≦10×(4.91x 1 / 2 ×(v / U) 1 / 2 )…(1)

[0070] In the above formula 1, "4.91x 1 / 2 ×(v / U) 1 / 2 " indicates the thickness of the laminar boundary layer, in meters. By setting the dimension L of the airflow guiding surface 464A in the +Y direction and the intersection angle θ between the airflow guiding surface 464A and the extension plane of the surface 46B within a range that satisfies the above formula 1, it is possible to suitably guide the cooling air to the entrance-side dustproof substrate 425 exposed within the opening 461. In addition, since the required dimension L can be reduced, the dimension of the heat-transfer frame 46 along the +Y direction can be reduced, and therefore the optical modulation device 34 can be made smaller.

[0071] [Control device configuration] FIG. 18 is a block diagram showing the configuration of the control device 7. The control device 7 controls the operation of the projector 1. For example, the control device 7 controls the operation of the heating elements 47 and fans 61 and 62 of each of the panel modules 4B, 4G, and 4R in accordance with the temperature of the liquid crystal panel 41 of each of the panel modules 4B, 4G, and 4R. As shown in FIG. 18, the control device 7 includes a temperature sensor 71, a storage unit 72, and a control unit 73. In the following description, the liquid crystal panel 41 and the heating element 47 of the blue panel module 4B are referred to as the blue liquid crystal panel 41B and the blue heating element 47B. The liquid crystal panel 41 and the heating element 47 of the green panel module 4G are referred to as the green liquid crystal panel 41G and the green heating element 47G. The liquid crystal panel 41 and the heating element 47 of the red panel module 4R are referred to as the red liquid crystal panel 41R and the red heating element 47R.

[0072] [Temperature sensor configuration] The temperature sensor 71 is provided in the light modulation device 34 and detects the temperature of the liquid crystal panel 41, and therefore the temperature of the liquid crystal layer 422. The control device 7 has three temperature sensors 71, including temperature sensors 71B, 71G, and 71R. The temperature sensor 71B detects the temperature of the blue liquid crystal panel 41B. The temperature sensor 71G detects the temperature of the green liquid crystal panel 41G. The temperature sensor 71R detects the temperature of the red liquid crystal panel 41R. Each of the temperature sensors 71B, 71G, and 71R outputs the detected temperature to the control unit 73.

[0073] FIG. 19 is a diagram showing the position of the temperature sensor 71B on the blue liquid crystal panel 41B. 19, the temperature sensor 71B is provided on the blue liquid crystal panel 41B on the upstream side of the cooling airflow. More specifically, the temperature sensor 71B is arranged on the blue liquid crystal panel 41B in the -Y direction, which is upstream of the cooling airflow with respect to the modulation area PA. In this embodiment, the temperature sensor 71B is arranged outside the modulation area PA and in the -Y direction with respect to the modulation area PA on the output-side substrate 424, which is a TFT substrate. The same applies to the temperature sensor 71G provided on the green liquid crystal panel 41G and the temperature sensor 71R provided on the red liquid crystal panel 41R.

[0074] Here, when the temperature sensor 71 is disposed downstream of the cooling air relative to the modulation area PA, if the heating element 47 generates heat, a high temperature may be detected even if the portion of the modulation area PA upstream of the cooling air is not sufficiently warmed. In this case, if the control unit 73 (described later) reduces the heat generation of the heating element 47 when the temperature of the portion of the modulation area PA downstream of the cooling air is not sufficiently high, the liquid crystal responsiveness in that downstream portion may decrease, and it may become impossible to display high-resolution images. In contrast, by positioning the temperature sensor 71 on the upstream side where the cooling effect of the cooling air is higher than in the downstream portion, if the temperature detected by the temperature sensor 71 is within the target temperature range, it can be said that the entire modulation area PA is within the target temperature range, and the above-mentioned decrease in liquid crystal responsiveness can be suppressed.

[0075] [Storage configuration] 18 is configured by a storage device such as a nonvolatile memory, and stores programs and data necessary for controlling the projector 1. For example, the storage unit 72 stores a control program that causes the control unit 73 to execute a control process described below. Also, for example, the storage unit 72 stores various threshold values ​​necessary for the control process.

[0076] [Overview of the control unit] FIG. 20 is a flowchart showing the control process executed by the control unit 73. 18 is configured by a processor such as a CPU (Central Processing Unit), and controls the operation of each component of the projector 1 in accordance with a program read from the storage unit 72. For example, the control unit 73 executes a control process to control the operation of the heating element 47 and the fans 61 and 62 based on the temperature of the liquid crystal panel 41 measured by the temperature sensor 71. Specifically, as shown in Fig. 20, the control unit 73 first starts temperature detection by the temperature sensor 71 and acquires the detection result from the temperature sensor 71 (step S01). That is, the control unit 73 acquires the temperatures of the liquid crystal panels 41B, 41G, and 41R from the temperature sensors 71B, 71G, and 71R. The control unit 73 acquires the temperatures of the liquid crystal panels 41B, 41G, and 41R from the temperature sensors 71B, 71G, and 71R periodically or at predetermined timings. Specifically, the control unit 73 acquires the temperatures of the liquid crystal panels 41B, 41G, and 41R from the temperature sensors 71B, 71G, and 71R at timings for determining the temperatures of the liquid crystal panels 41B, 41G, and 41R.

[0077] Next, the control unit 73 determines whether or not the acquired temperatures of the liquid crystal panels 41B, 41G, and 41R are lower than the lower limit of the target temperature range (step S02). If the judgment process of step S02 determines that there is an LCD panel 41 whose temperature is lower than the lower limit of the target temperature range (step S02: YES), the control unit 73 determines whether the output of the heating element 47 that heats the LCD panel 41 has reached its upper limit (step S03). If it is determined in the determination process of step S03 that the output of the heating element 47 has not reached the upper limit (step S03: NO), the control unit 73 increases the output of the corresponding heating element 47 to intensify the heating of the liquid crystal panel 41 by that heating element 47 (step S04).On the other hand, the control unit 73 does not increase the output of the heating element 47 that heats the liquid crystal panel 41 whose temperature is not lower than the lower limit of the target temperature range. After step S04, the control unit 73 returns the process to step S02.

[0078] If it is determined in the determination process of step S03 that the output of the heating elements 47 has reached the upper limit (step S03: YES), the control unit 73 operates the projector 1 in low resolution mode (step S05). At this time, if the control unit 73 determines that the output of even one heating element 47 has reached the upper limit, it determines that the output of the heating element 47 has reached the upper limit, and executes step S05. In step S05, the control unit 73 sets the frame rate to 60 Hz or 120 Hz and operates each of the liquid crystal panels 41B, 41G, and 41R. If the frame rate of the liquid crystal panel 41 is 60 Hz, the control unit 73 stops the optical path changing element 36. For example, if the frame rate of the liquid crystal panel 41 is 120 Hz, the control unit 73 sets the drive frequency of the optical path changing element 36 to 120 Hz to match the frame rate of the liquid crystal panel 41, and sets the image display positions moved by the optical path changing element 36 to two positions: a first position P1 and a third position P3. As a result, although the resolution of the projected image is lower than when the frame rate of the liquid crystal panel 41 and the drive frequency of the optical path changing element 36 are 240 Hz, the projected image can be displayed on the projection surface without degrading image quality. After step S05, the control unit 73 ends the control process.

[0079] If it is determined in the judgment process of step S02 that there is no liquid crystal panel 41 whose temperature is lower than the lower limit of the target temperature range (step S02: NO), the control unit 73 determines whether the temperature of each liquid crystal panel 41B, 41G, 41R is higher than the upper limit of the target temperature range (step S06). If it is determined in the determination process of step S06 that the temperatures of the liquid crystal panels 41B, 41G, and 41R are not higher than the upper limit of the target temperature range (step S06: NO), the control unit 73 proceeds to step S14. As will be described in detail later, in step S12, the control unit 73 operates the projector 1 in high resolution mode. Note that if the temperature of at least one liquid crystal panel 41 is higher than the upper limit of the target temperature range, the control unit 73 determines that the temperature of the liquid crystal panel 41 is higher than the upper limit of the target temperature range.

[0080] If the judgment process of step S06 determines that there is an LCD panel 41 whose temperature is higher than the upper limit of the target temperature range (step S06: YES), the control unit 73 determines whether the output of the heating element 47 that heats the LCD panel 41 whose temperature is determined to be high has reached its lower limit (step S07). If it is determined in the determination process of step S07 that the output of the heating element 47 that heats the liquid crystal panel 41 determined to have a high temperature has not reached the lower limit (step S07: NO), the control unit 73 reduces the output of the heating element 47 to weaken the heating of the liquid crystal panel 41 by the heating element 47 (step S08).On the other hand, the control unit 73 does not reduce the output of the heating element 47 that heats the liquid crystal panel 41 whose temperature is not higher than the upper limit of the target temperature range. After step S08, the control unit 73 returns the process to step S06.

[0081] If it is determined in the judgment process of step S07 that the output of the heating element 47 that heats the liquid crystal panel 41, whose temperature is determined to be high, has reached its lower limit (step S07: YES), the control unit 73 determines whether the output of the fans 61, 62 has reached its upper limit (step S09).

[0082] If it is determined in the determination process of step S09 that the outputs of the fans 61, 62 have reached their upper limits (step S09: YES), the control unit 73 notifies the user of a temperature abnormality in a predetermined manner (step S10). For example, the control unit 73 may notify the user of the abnormality by lighting or blinking an indicator, or may cause the light modulation device 34 to form an image indicating the abnormality and have the projection optical device 37 project the image. After step S10, the control unit 73 shuts down the projector 1 (step S11) and ends the control process.

[0083] If it is determined in the determination process of step S09 that the outputs of the fans 61 and 62 have not reached their upper limits (step S09: NO), the control unit 73 increases the outputs of the fans 61 and 62 (step S12), thereby increasing the flow rate of the cooling air circulating through each of the liquid crystal panels 41B, 41G, and 41R, and improving the cooling efficiency of each of the liquid crystal panels 41B, 41G, and 41R. After step S12, the control unit 73 determines whether the temperature of each of the liquid crystal panels 41B, 41G, and 41R is higher than the upper limit of the target temperature range, similar to step S05 (step S13).

[0084] If it is determined in the determination process of step S13 that there is a liquid crystal panel 41 whose temperature is higher than the upper limit of the target temperature range (step S13: YES), the control unit 73 returns the process to step S09, whereby the outputs of the fans 61 and 62 are increased unless the outputs of the fans 61 and 62 have reached their upper limits.

[0085] If it is determined in the determination process of step S13 that the temperatures of the liquid crystal panels 41B, 41G, and 41R are not higher than the upper limit of the target temperature range (step S13: NO), the control unit 73 operates the projector 1 in high-resolution mode (step S14). For example, the control unit 73 sets the frame rate to 240 Hz and operates each of the liquid crystal panels 41B, 41G, and 41R. The control unit 73 sets the drive frequency of the optical path changing element 36 to 240 Hz to match the frame rate of the liquid crystal panel 41, and sets the image display position moved by the optical path changing element 36 to four positions P1 to P4. This makes it possible to increase the resolution of the projected image. After step S14, the control unit 73 ends the control process. Such control processing is repeatedly executed at predetermined intervals.

[0086] [Effects of the first embodiment] The projector 1 according to the present embodiment described above has the following advantages. The projector 1 includes a light source 31 and a light modulation device 34 that modulates the light emitted from the light source 31. The light modulation device 34 includes a liquid crystal panel 41 and a temperature control unit 45. The liquid crystal panel 41 has a liquid crystal layer 422, an incident-side substrate 423, an exit-side substrate 424, an incident-side dustproof substrate 425, and an exit-side dustproof substrate 426. The incident-side substrate 423 is located on the light incident side with respect to the liquid crystal layer 422. The exit-side substrate 424 is located on the light exit side with respect to the liquid crystal layer 422, and together with the incident-side substrate 423, they sandwich the liquid crystal layer 422. The incident-side dustproof substrate 425 is light-transmitting and is located on the light incident side with respect to the incident-side substrate 423. The exit-side dustproof substrate 426 is light-transmitting and is located on the light exit side with respect to the exit-side substrate 424. The exit-side dustproof substrate 426, together with the incident-side dustproof substrate 425, sandwich the liquid crystal layer 422, the incident-side substrate 423, and the exit-side substrate 424. The plane size of the incident-side dustproof substrate 425 is larger than the plane size of the incident-side substrate 423 when viewed from the light incident side of the optical modulator 34 . The temperature control unit 45 controls the temperature of the liquid crystal layer 422. The temperature control unit 45 is in contact with the incident-side dustproof substrate 425.

[0087] With this configuration, the planar size of the incident-side dustproof substrate 425 is larger than the planar size of the incident-side substrate 423, which makes it easier to transfer heat from the temperature control unit 45 to the incident-side substrate 423 via the incident-side dustproof substrate 425. This makes it easier to transfer heat to the liquid crystal layer 422 via the incident-side substrate 423, which makes it possible to quickly adjust the temperature of the liquid crystal layer 422. This makes it possible to control the temperature of the liquid crystal layer 422 more accurately than when a heating element is formed of a transparent conductive film disposed in a region through which light passes. Furthermore, this makes it possible to quickly increase the temperature of the liquid crystal layer 422 by the temperature control unit 45 when the temperature of the liquid crystal layer 422 is low, for example, thereby improving the responsiveness of the liquid crystal layer 422 and, ultimately, the light modulation device 34.

[0088] In the projector 1, the thermal conductivity of the incident-side dustproof substrate 425 is equal to or greater than the thermal conductivity of the incident-side substrate 423. This configuration makes it easier to transfer heat from the incident-side dustproof substrate 425, which is in contact with the temperature control unit 45, to the incident-side substrate 423. Therefore, the responsiveness of the optical modulation device 34 can be further improved.

[0089] In the projector 1, the temperature control unit 45 has a heat transfer frame 46 that is in contact with the incident side dustproof board 425 and supports the incident side dustproof board 425, and a heating element 47 that is provided on the heat transfer frame 46. According to this configuration, compared to when the heat of the heating element 47 is directly transferred to the entrance-side dustproof board 425, it is possible to more easily prevent the heat of the heating element 47 from being transferred locally to the entrance-side dustproof board 425. Furthermore, since the heating element 47 is provided on the heat-transfer frame 46 that supports the entrance-side dustproof board 425, the entrance-side dustproof board 425 and the heating element 47 can be supported by the heat-transfer frame 46. Therefore, it is possible to improve the ease of assembly of the optical modulation device 34.

[0090] In the projector 1, the heat transfer frame 46 is recessed toward the incident-side dustproof board 425 and has an arrangement portion 463 inside which the heat generating element 47 is arranged. This configuration makes it easier to arrange the heating element 47 on the heat-transfer frame 46. Furthermore, because the arrangement portion 463 is a recess that is recessed toward the entrance-side dustproof board 425, it is possible to shorten the distance between the entrance-side dustproof board 425 and the heating element 47. Therefore, it is possible to easily transfer heat generated by the heating element 47 to the entrance-side dustproof board 425, and the entrance-side dustproof board 425 can be quickly heated.

[0091] In the projector 1, the heat generating element 47 is configured in a frame shape having a passage opening through which light incident on the incident-side dustproof board 425 passes. With this configuration, when viewed from the light incident side of the incident-side dustproof substrate 425, heat generated by the heating element 47 can be transferred to the peripheral portion located outside the light incident region of the incident-side dustproof substrate 425. This makes it easier to increase the temperature of the entire incident-side dustproof substrate 425, and ultimately the temperature of the liquid crystal layer 422, compared to when heat is transferred only to the edge of the incident-side dustproof substrate 425.

[0092] The projector 1 includes an optical path changing element 36 that changes the optical path of light modulated by the optical modulation device 34. The optical path changing element 36 includes an optical member 361, a first holding member 362, a second holding member 363, a base 364, a first actuator 365, and a second actuator 366. The optical member 361 receives the light modulated by the light modulation device 34 . The first holding member 362 holds the optical member 361, and the second holding member 363 holds the first holding member 362, thereby holding the optical member 361. That is, the first holding member 362 and the second holding member 363 correspond to the holding members of the present disclosure. The first actuator 365 swings the first holding member 362 , and the second actuator 366 swings the second holding member 363 . The light modulation device 34 has a modulation area PA that modulates incident light, and the modulation area PA has a rectangular shape having short and long sides when viewed from the light incident side. The heating element 47 is disposed at a position different from that of each of the actuators 365 and 366 in the +D2 direction along the short side of the modulation area PA.

[0093] According to this configuration, the resolution of the image projected by the projector 1 can be increased by driving the optical path changing element 36 at high speed. Furthermore, by arranging the heating element 47 at a position different from the actuators 365, 366 of the optical path changing element 36 in the +D2 direction along the short side of the modulation area PA, it is possible to prevent the heat generated by the heating element 47 from adversely affecting the actuators 365, 366. Therefore, it is possible to operate the optical path changing element 36 stably.

[0094] In the projector 1, the temperature control unit 45 is provided on the opposite side of the heat transfer frame 46 with respect to the heat generating element 47, and has a cover member 48 that covers at least a part of the heat generating element 47. The thermal conductivity of the cover member 48 is lower than the thermal conductivity of the heat transfer frame 46. With this configuration, the thermal conductivity of the cover member that covers at least a portion of the heat-generating element is lower than the thermal conductivity of the heat-transfer frame, which facilitates the transfer of heat from the heat-generating element to the heat-transfer frame, thereby facilitating the transfer of heat generated by the heat-generating element to the entrance-side dustproof substrate via the heat-transfer frame.

[0095] In the projector 1, the cover member 48 has an absorption layer 483 that is provided on a surface 481A of the cover member 48 on the light incident side and that absorbs visible light. With this configuration, the absorbing layer 483 absorbs at least a portion of the light that does not enter the incident-side dustproof substrate 425, thereby heating the cover member 48. As a result, when it is necessary to heat the liquid crystal layer 422, not only the heat generated by the heating element 47 but also the heat generated by the absorbing layer 483 can be transferred to the liquid crystal layer 422. Therefore, it is possible to easily heat the liquid crystal layer 422.

[0096] The projector 1 includes a holding frame 44 that is separate from the heat transfer frame 46. The holding frame 44 is combined with the heat transfer frame 46 to house a liquid crystal layer 422, an incident side substrate 423, an exit side substrate 424, an incident side dustproof substrate 425, and an exit side dustproof substrate 426. According to this configuration, by combining the heat transfer frame 46 and the holding frame 44, the liquid crystal layer 422, the incident side substrate 423, the exit side substrate 424, the incident side dustproof substrate 425, and the exit side dustproof substrate 426 can be held, thereby protecting the liquid crystal layer 422, the incident side substrate 423, the exit side substrate 424, the incident side dustproof substrate 425, and the exit side dustproof substrate 426. Furthermore, because the heat transfer frame 46 is separate from the holding frame 44, the heat transfer frame 46 can be configured to match the shape of the incident-side dustproof board 425. Therefore, the heat transfer frame 46 can be configured so that the contact area with the incident-side dustproof board 425 is large, and the efficiency of heat transfer between the heat transfer frame 46 and the incident-side dustproof board 425 can be improved.

[0097] In the projector 1, the heat transfer frame 46 has a surface 46B as a first surface facing the light incident side relative to the light modulation device 34, an opening 461 through which light incident on the incident side dustproof substrate 425 passes, and an air guide surface 464A that extends along the surface 46B in a direction away from the opening 461 and guides cooling air to the incident side dustproof substrate 425 exposed through the opening 461. With this configuration, the air guide surface 464A can guide the cooling air to the incident-side dustproof substrate 425 exposed within the opening 461, thereby cooling the incident-side dustproof substrate 425 to which heat from the liquid crystal layer 422 is transmitted via the incident-side substrate 423, and ultimately cooling the liquid crystal layer 422.

[0098] In the projector 1, the above formula 1 is satisfied when the dimension of the airflow guiding surface 464A in the +Y direction is L, the intersection angle between the airflow guiding surface 464A and the extension plane of surface 46B is θ, the dimension of the opening 461 in the +Y direction is x, the dynamic viscosity coefficient of air is v, and the wind speed of the airflow flowing in the +Y direction is U. Note that the +Y direction corresponds to the airflow direction toward the opening 461 along the airflow guiding surface 464A. By satisfying the above formula 1, it is possible to set the crossing angle θ and the dimension L that allow the airflow to efficiently flow toward the incident-side dustproof substrate 425 exposed in the opening 461. Therefore, it is possible to improve the cooling efficiency of the liquid crystal layer 422 while miniaturizing the light modulation device 34.

[0099] The projector 1 is provided with a temperature sensor 71 provided in the light modulation device 34 for detecting the temperature of the liquid crystal layer 422, fans 61 and 62 for circulating cooling gas through the light modulation device 34, and a control unit 73 for controlling the heating element 47 and the fans 61 and 62 based on the temperature of the liquid crystal layer 422 detected by the temperature sensor 71. With this configuration, it is possible to control the driving state of the heating element 47 that heats the liquid crystal layer 422 and the driving state of the fans 61 and 62 that circulate the cooling gas that cools the liquid crystal layer 422, depending on the temperature of the liquid crystal layer 422. This makes it possible to maintain the temperature of the liquid crystal layer 422 within a temperature range that is suitable for driving the liquid crystal layer 422, for example. Therefore, it is possible to maintain a high responsiveness of the liquid crystal layer 422.

[0100] [Second embodiment] Next, a second embodiment of the present disclosure will be described. The projector according to this embodiment has a similar configuration to the projector 1 according to the first embodiment, but the configuration of the optical path changing element is different. In the following description, parts that are the same or approximately the same as parts that have already been described will be assigned the same reference numerals and description thereof will be omitted.

[0101] [Projector configuration] 21 is a perspective view of an image forming device 33A provided in a projector according to this embodiment, as viewed from the output side of the image light PL. Note that in FIG. 21, the field lens 331 and the incident-side polarizing plate 332 are omitted from the illustration. The projector according to this embodiment has the same configuration and functions as the projector 1 according to the first embodiment, except that it has an image forming device 33A shown in FIG.

[0102] [Configuration of optical path changing element] FIG. 22 is a diagram showing the optical path changing element 38 as viewed from the emission side of the image light PL. Similar to the optical path changing element 36, the optical path changing element 38 is disposed between the light combining element 35 and the projection optical device 37 in the optical path of the image light PL, and shifts the optical path of the image light PL incident from the light combining element 35 to increase the resolution of the projection image displayed by the image light PL projected onto the projection surface PS. That is, the optical path changing element 38 is disposed on the output side of the image light PL with respect to the light combining element 35, as shown in FIG.

[0103] As shown in FIGS. 21 and 22, the optical path changing element 38 includes an optical member 361, a holding member 382, ​​a base 383, and an actuator 384. In this embodiment, the optical element 361 is held by a holding element 382, ​​and when the actuator 384 is operated, the optical element 361 is tilted relative to a virtual plane perpendicular to the output optical axis of the image light PL of the light combining element 35, thereby shifting the optical path of the image light PL by refraction.

[0104] 22, similar to the first holding member 362, the holding member 382 is formed in a rectangular frame shape, holds the optical member 361, and is held by a base 383 so as to be swingable about an oscillation axis Rx. The holding member 382 has a frame portion 3821, shaft portions 3822 and 3823, fixed portions 3824 and 3825, and a support portion 3826. The oscillation axis Rx is an axis that is inclined with respect to both the +D2 direction and the +D3 direction, and approaches the +D3 direction as it approaches the +D2 direction.

[0105] The frame portion 3821 surrounds and supports the optical member 361. The frame portion 3821 has an opening (not shown) through which light passing through the optical member 361 passes. The shaft portion 3822 protrudes from the outer periphery of the frame portion 3821 in the +D2 and +D3 directions, and the shaft portion 3823 protrudes from the outer periphery of the frame portion 3821 in the -D2 and -D3 directions. The fixed portion 3824 is provided at the tip of the shaft portion 3822, and the fixed portion 3825 is provided at the tip of the shaft portion 3823. By fixing the fixed portions 3824 and 3825 to the base 383, the holding member 362 is supported by the base 383 so as to be swingable about the swing axis Rx. Support portion 3826 is provided at the corners in the +D2 and -D3 directions on the outer periphery of frame portion 3821. Support portion 3826 supports magnet 3841 that constitutes actuator 384. Support portion 3826 is made of metal, and functions as a back yoke for magnet 3841 that it supports.

[0106] The base 383 holds the holding member 363 so that it can swing about the swing axis Rx, and also holds the coil 3842 of the actuator 384. The base 383 is formed in a frame shape, and has an opening 3831 in which the holding member 382 is disposed.

[0107] The actuator 384 swings the holding member 362 about the oscillation axis Rx, thereby swinging the optical member 361 about the oscillation axis Rx. The actuator 384 has a magnet 3841 and a coil 3842. That is, the actuator 384 is a voice coil motor that has the magnet 3841 fixed to the holding member 382 and the coil 3842 fixed to the base 383. The control device 7 supplies an alternating current to the coil 3842, whereby the optical member 361 held by the holding member 382 is oscillated about the oscillation axis Rx.

[0108] [Optical path shift by optical path changing element] FIG. 23 is a diagram illustrating the shift of the optical path of the image light by the optical path changing element 38. In FIG. The optical path changing element 38 changes the attitude of the optical member 361 through which the image light PL passes, thereby shifting the optical path of the image light PL by utilizing refraction at the optical member 361. Specifically, the optical path changing element 38 causes the actuator 384 to swing the optical member 361 around the swing axis Rx, thereby shifting the optical path of the image light PL in a direction perpendicular to the swing axis Rx when viewed from the incident side of the image light PL relative to the optical path changing element 38. As a result, as shown in Fig. 23 , the pixels Px of the projection image displayed on the projection surface PS are shifted in the +F1 direction and the -F2 direction to a first position P1, and in the -F1 direction and the +F2 direction to a third position P3. The control device 7 uses the optical path changing element 38 to combine shifting of pixel Px in the +F1 direction and the -F2 direction with shifting of pixel Px in the -F1 direction and the +F2 direction, thereby increasing the apparent number of pixels and increasing the resolution of the projected image.

[0109] For example, the control device 7 moves the pixel Px to a position shifted by half a pixel in each of the -F1 direction and the +F2 direction by shifting the optical path of the image light using the optical path changing element 38. Note that half a pixel refers to a size that is half that of the pixel Px. As a result, the display position of pixel Px on projection surface PS is shifted to position PC, which is shifted by half a pixel in the -F1 direction and +F2 direction from position PA, which is the reference position.

[0110] In this way, the control device 7 shifts the optical path of the image light PL by the optical path changing element 38 so that pixel Px is displayed at positions P1 and P3 for a fixed time, and changes the display content of each liquid crystal panel 41B, 41G, and 41R in synchronization with the optical path shift, thereby making it possible to display pixels A and C that appear smaller than the size of pixel Px. For example, if pixels A and C are displayed at an overall frequency of 60 Hz, the display of each of liquid crystal panels 41B, 41G, and 41R must be switched at twice the speed of 60 Hz, corresponding to positions P1 and P3. In this case, by setting the frame rate of each liquid crystal panel 41 to 120 Hz and each liquid crystal panel 41 sequentially forming image light including pixel A displayed at first position P1 and image light including pixel C displayed at third position P3, a projected image with a high apparent resolution can be displayed.

[0111] [Positional relationship between heating element and actuator] Fig. 24 is a diagram showing the positional relationship between the heating elements 47 of the optical modulation devices 34B and 34G and the actuator 384 of the optical path changing element 38, as viewed from the blue light incident side. Fig. 25 is a diagram showing the positional relationship between the heating elements 47 of the optical modulation devices 34B, 34G, and 34R and the actuator 384, as viewed from the light emission side of the optical path changing element 38. Fig. 12 shows arrows indicating the +D1 direction, +D2 direction, and +D3 direction, as well as arrows indicating the +X direction, +Y direction, and +Z direction of the optical modulation device 34B.

[0112] In this embodiment, of the three optical modulation devices 34B, 34G, and 34R, the heating element 47 of the optical modulation device 34B, which is closest to the actuator 384, is positioned at a position away from the actuator 384 in the +D2 direction, as shown in Figures 24 and 25. As described above, the heating element 47 of the light modulation device 34B is provided at a position surrounding the modulation area PA through which the blue light passes in the light modulation device 34B. On the other hand, as shown in FIG. 22 , the actuator 384 is disposed so as to be shifted in the +D2 direction with respect to the optical member 361 through which the image light PL passes in the light path changing element 38. As described above, the +D2 direction is the direction along the short side of the modulation area PA of the light modulation device 34B. For this reason, the heating element 47 of the light modulation device 34B is disposed at a position spaced apart from the actuators 365, 366 in the -D2 direction.

[0113] In this way, by arranging the actuator 384 and the heating element 47 of the optical modulation device 34B closest to the actuator 384 at a distance in the +D2 direction, it is possible to prevent the magnet 3841 of the actuator 384 from being thermally affected by the heating element 47 of the optical modulation device 34B. The heating element 47 of the optical modulation device 34G is not only disposed at a position spaced apart from the actuator 384 in the -D2 direction, but also at a position spaced apart from the actuator 384 in the -D1 direction. Furthermore, the heating element 47 of the optical modulation device 34R is not only disposed at a position spaced apart from the actuator 384 in the −D2 direction, but also at a position spaced apart in the +D3 direction. Therefore, the heat generated by the heating elements 47 of the optical modulation devices 34G and 34R does not have a significant effect on the actuator 384. Therefore, it is possible to prevent demagnetization of the magnet 3841 of the actuator 384, and to prevent the operation of the optical path changing element 38 from being hindered by heat. The projector according to this embodiment described above can achieve the same effects as the projector 1 according to the first embodiment.

[0114] [Modification of the embodiment] The present disclosure is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present disclosure are included in the present disclosure. In the above embodiments, the thermal conductivity of the incident-side dustproof substrate 425 is equal to or greater than the thermal conductivity of the incident-side substrate 423. However, the present invention is not limited to this, and the thermal conductivity of the incident-side dustproof substrate 425 may be less than the thermal conductivity of the incident-side substrate 423.

[0115] In each of the above embodiments, the temperature control unit 45 includes the heat transfer frame 46, the heating element 47, and the cover member 48. However, the configuration of the temperature control unit 45 is not limited to the above. For example, the temperature control unit 45 may not include the heat transfer frame 46 and the cover member 48, and the heating element 47 may be provided so as to be in direct contact with the incident-side dustproof substrate 425. In this case, the heating element 47 may be in contact with a surface of the incident-side dustproof substrate 425 other than the light incident surface 425A. In this case, a frame may be provided that is disposed on the light incident side of the panel body 42 and that is combined with the holding frame 44.

[0116] In each of the above embodiments, the heating element 47 transfers heat to the light incident surface 425A of the incident-side dustproof substrate 425 via the heat-transfer frame 46. In other words, the contact portion 462 of the heat-transfer frame 46, to which heat is transferred from the heating element 47, is in contact with the light incident surface 425A of the incident-side dustproof substrate 425 so as to be able to transfer heat. However, this is not limiting, and the contact portion 462 may be in contact with, for example, a side surface of the incident-side dustproof substrate 425 that connects the light incident surface 425A and the surface on the light exit side. In other words, the surface of the incident-side dustproof substrate 425 that the heat-transfer frame 46 contacts is not limited to the light incident surface 425A, and may be another surface.

[0117] In each of the above embodiments, the heat transfer frame 46 has a concave arrangement portion 463 that is concave from the light incident side surface 46B of the heat transfer frame 46 toward the incident-side dustproof board 425, and the heating element 47 is arranged in the arrangement portion 463. However, this is not limiting, and the arrangement portion 463 on which the heating element 47 is arranged does not have to be concave from the surface 46B toward the incident-side dustproof board 425.

[0118] In each of the above embodiments, the heating element 47 is formed in a rectangular frame shape having a passage opening 471 through which light incident on the incident-side dustproof substrate 425 passes. However, the shape of the heating element 47 is not limited to this, and can be changed as appropriate. For example, the heating element 47 may be a heating element that extends linearly along at least one edge of the modulation area PA. In this case, the temperature control unit 45 may be provided with multiple heating elements 47. In this case, for example, the heating element 47 may be configured to have two heating elements that extend along two long sides and two heating elements that extend along two short sides of the four edges of the modulation area PA.

[0119] In the first embodiment, the optical path changing element 36 includes an optical member 361, a first holding member 362 and a second holding member 363 as holding members, a base 364, and a first actuator 365 and a second actuator 366 as actuators for oscillating the holding members. In the second embodiment, the optical path changing element 38 includes an optical member 361, a holding member 382, ​​a base 383, and an actuator 384. However, the configuration and arrangement of the optical path changing elements 36, 38 are not limited to those described above. For example, the optical path changing elements 36, 38 may be configured to oscillate the optical member 361 using other actuators such as a motor and a solenoid. Furthermore, the first oscillation axis Rx1 of the optical path changing element 36 is along the +D3 direction, and the second oscillation axis Rx2 is along the +D2 direction. However, this is not limiting, and the first oscillation axis Rx1 may intersect with both the +D2 direction and the +D3 direction, and the second oscillation axis Rx2 may intersect with the first oscillation axis Rx1 and also with both the +D2 direction and the +D3 direction. Similarly, the oscillation axis Rx of the optical path changing element 38 may be along the +D2 direction or the +D3 direction, or may extend in a direction that is the inverse of the direction of the oscillation axis Rx shown in Figure 22 around an axis along the +D2 direction.

[0120] In the first embodiment, the heating element 47 is arranged at a different position from the first actuator 365 and the second actuator 366 in the +D2 direction along the short side of the modulation area PA. Specifically, the heating element 47 is arranged in the −D2 direction relative to the first actuator 365 and the second actuator 366. In the second embodiment, the heating element 47 is arranged at a different position from the actuator 384 in the +D2 direction along the short side of the modulation area PA. Specifically, the heating element 47 is arranged in the −D2 direction relative to the actuator 384. However, this is not limited to this. The heating element 47 according to the first embodiment may be arranged in the +D2 direction relative to the actuators 365 and 366, and the heating element 47 according to the second embodiment may be arranged in the +D2 direction relative to the actuator 384. Furthermore, the heating element 47 may be arranged at the same position as the actuators 365, 366, and 384 in the +D2 direction.

[0121] In each of the above embodiments, the temperature control unit 45 includes a cover member 48 that covers a portion of the heating element 47, and the thermal conductivity of the cover member 48 is lower than the thermal conductivity of the heat transfer frame 46. However, as described above, the cover member 48 may be omitted. Furthermore, the thermal conductivity of the cover member 48 may be equal to or higher than the thermal conductivity of the heat transfer frame 46.

[0122] In each of the above embodiments, the cover member 48 has the absorption layer 483 that absorbs visible light. However, this is not limiting, and the absorption layer 483 may be omitted. Furthermore, the absorption layer 483 may absorb ultraviolet light.

[0123] In each of the above embodiments, the light modulation device 34 is configured separately from the heat transfer frame 46 and includes the holding frame 44 that is combined with the heat transfer frame 46 to house the panel main body 42. However, this is not limiting, and the heat transfer frame 46 may be configured to hold the panel main body 42. In this case, the holding frame 44 may be omitted.

[0124] In each of the above embodiments, the heat-transfer frame 46 has the opening 461 through which light incident on the incident-side dustproof board 425 passes and which exposes the incident-side dustproof board 425, and the airflow guiding surface 464A that guides cooling air to the incident-side dustproof board 425. However, the present invention is not limited to this, and the airflow guiding surface 464A may be omitted. In each of the above embodiments, the heat transfer frame 46 having the airflow guiding surface 464A satisfies the above formula 1. However, this is not limiting, and for example, when the space in the -D2 direction relative to the light modulation device 34 is sufficiently large, the above formula 1 does not necessarily have to be satisfied.

[0125] In each of the above embodiments, the projector includes the temperature sensor 71 that is provided on the output-side substrate 424 of the light modulation device 34 and detects the temperature of the liquid crystal layer 422, the fans 61 and 62 that send cooling gas to the light modulation device 34, and the control unit 73 that controls the heating element 47 and the fans 61 and 62 based on the temperature of the liquid crystal layer 422 detected by the temperature sensor 71. However, this is not limiting, and the control unit 73 does not necessarily have to control the heating element 47 and the fans 61 and 62 based on the temperature of the liquid crystal layer 422. Furthermore, the number of fans that send out cooling gas to the optical modulators 34 may be one fan or three or more fans. For example, the flow of cooling gas sent out from one fan may be divided and circulated to each of the optical modulators 34, or the flow of cooling gas sent out from each of three fans may be circulated to the corresponding optical modulators 34.

[0126] In each of the above embodiments, the temperature sensor 71 is provided on the output-side substrate 424. However, the present invention is not limited to this, and the temperature sensor 71 may be provided anywhere in the optical modulation device 34 as long as it can detect the temperature of the liquid crystal layer 422. For example, the temperature sensor 71 may be provided on the input-side substrate 423. Furthermore, the temperature sensor 71 does not necessarily have to be provided in a portion upstream of the cooling air relative to the modulation area PA. For example, the temperature sensor 71 may be provided in a portion downstream of the cooling air relative to the modulation area PA, or may be provided in a direction perpendicular to the flow direction of the cooling air relative to the modulation area PA when viewed from the light incident side or light exit side.

[0127] In the above embodiments, the projector 1 includes three light modulation devices 34B, 34G, and 34R. However, the present disclosure is not limited to this and can also be applied to a projector including two or less light modulation devices, or four or more light modulation devices. In each of the above embodiments, the image projection device 3 has the configuration shown in Fig. 1. However, the present invention is not limited to this, and the type, number, and layout of the optical components that make up the image projection device 3 can be changed as appropriate.

[0128] Summary of this disclosure A summary of this disclosure is provided below. [Appendix 1] A light source and a light modulation device that modulates the light emitted from the light source, The optical modulation device A liquid crystal layer; an incident-side substrate located on the light incident side with respect to the liquid crystal layer; an emission-side substrate located on the light emission side of the liquid crystal layer and sandwiching the liquid crystal layer together with the incident-side substrate; an incident-side dustproof substrate that is light-transmitting and positioned on the light incident side of the incident-side substrate; an exit-side dustproof substrate that has light transmissivity, is located on the light exit side of the exit-side substrate, and sandwiches the liquid crystal layer, the entrance-side substrate, and the exit-side substrate together with the entrance-side dustproof substrate; a temperature control unit for controlling the temperature of the liquid crystal layer; a planar size of the incident-side dustproof substrate as viewed from the light incident side of the optical modulation device is larger than a planar size of the incident-side substrate; the temperature control unit is in contact with the incident-side dust-proof substrate; A projector characterized by:

[0129] With this configuration, the planar size of the entrance-side dustproof member is larger than the planar size of the entrance-side substrate, which facilitates heat transfer from the temperature control unit to the entrance-side substrate via the entrance-side dustproof substrate. This facilitates heat transfer to the liquid crystal layer via the entrance-side substrate, allowing the temperature of the liquid crystal layer to be adjusted quickly. Therefore, the temperature of the liquid crystal layer can be controlled more accurately than when a heating element is formed by a transparent conductive film disposed in the light-passing region. Furthermore, this allows the temperature control unit to quickly increase the temperature of the liquid crystal layer when the temperature of the liquid crystal layer is low, thereby improving the responsiveness of the liquid crystal layer and, ultimately, the light modulation device.

[0130] [Appendix 2] 2. The projector according to claim 1, the thermal conductivity of the incident-side dust-proof substrate is equal to or greater than the thermal conductivity of the incident-side substrate; A projector characterized by: With this configuration, heat can be easily transferred from the entrance-side dustproof substrate with which the temperature control unit is in contact to the entrance-side substrate, thereby further improving the responsiveness of the optical modulation device.

[0131] [Appendix 3] In the projector according to Supplementary Note 1 or Supplementary Note 2, The temperature control unit a heat transfer frame that is in contact with the entrance-side dustproof substrate and supports the entrance-side dustproof substrate; a heating element provided on the heat transfer frame, A projector characterized by: With this configuration, compared to when the heat from the heating element is directly transferred to the entrance-side dustproof substrate, it is easier to prevent the heat from the heating element from being transferred locally to the entrance-side dustproof substrate. Also, since the heating element is provided on the heat-transfer frame that supports the entrance-side dustproof substrate, the entrance-side dustproof substrate and the heating element can be supported by the heat-transfer frame. Therefore, the assembly of the optical modulation device can be improved.

[0132] [Appendix 4] In the projector according to Supplementary Note 3, the heat transfer frame has a recessed portion that faces the incident-side dustproof substrate and has an arrangement portion in which the heating element is arranged. A projector characterized by: This configuration makes it easy to place the heating element on the heat-transfer frame. Furthermore, because the placement portion is a recess that is recessed toward the entrance-side dustproof board, the distance between the entrance-side dustproof board and the heating element can be shortened. This makes it easy to transfer heat generated by the heating element to the entrance-side dustproof board, allowing the entrance-side dustproof board to be heated quickly.

[0133] [Appendix 5] In the projector according to Supplementary Note 3 or Supplementary Note 4, the heat generating element is configured in a frame shape having a passage opening through which light incident on the incident-side dustproof substrate passes; A projector characterized by: With this configuration, when viewed from the light incident side of the incident-side dustproof substrate, heat generated by the heating element can be transferred to the peripheral portion of the incident-side dustproof substrate that is located outside the light incident region, making it easier to increase the temperature of the entire incident-side dustproof substrate, and ultimately the temperature of the liquid crystal layer, compared to when heat is transferred only to the edge of the incident-side dustproof substrate.

[0134] [Appendix 6] 6. The projector according to claim 3, an optical path changing element that changes the optical path of the light modulated by the optical modulation device; The optical path changing element is an optical member onto which the light modulated by the optical modulation device is incident; a holding member for holding the optical member; an actuator that swings the holding member, the light modulation device has a modulation region that modulates incident light, the modulation area has a rectangular shape having short sides and long sides when viewed from the light incident side, The heating element is disposed at a position different from the actuator in a direction along the short side. A projector characterized by:

[0135] According to this configuration, the optical path changing element is driven at high speed, thereby making it possible to increase the resolution of the image projected by the projector. Furthermore, by arranging the heating element at a position different from the actuator of the optical path changing element in the direction along the short side of the modulation area, it is possible to prevent the heat generated by the heating element from adversely affecting the actuator, thereby enabling stable operation of the optical path changing element.

[0136] [Appendix 7] 7. The projector according to claim 3, the temperature control unit is provided on the opposite side of the heat transfer frame with respect to the heat generating element, and includes a cover member that covers at least a portion of the heat generating element; The thermal conductivity of the cover member is lower than the thermal conductivity of the heat transfer frame. A projector characterized by: With this configuration, the thermal conductivity of the cover member that covers at least a portion of the heat-generating element is lower than the thermal conductivity of the heat-transfer frame, which facilitates the transfer of heat from the heat-generating element to the heat-transfer frame, thereby facilitating the transfer of heat generated by the heat-generating element to the entrance-side dustproof substrate via the heat-transfer frame.

[0137] [Appendix 8] 8. The projector according to claim 7, the cover member has an absorption layer provided on a light incident side surface of the cover member and absorbing visible light; A projector characterized by: With this configuration, the absorbing layer absorbs at least a portion of the light that does not enter the entrance-side dustproof substrate, thereby heating the cover member. As a result, when it is necessary to heat the liquid crystal layer, not only the heat generated by the heating element but also the heat generated by the absorbing layer can be transferred to the liquid crystal layer. Therefore, it is possible to easily heat the liquid crystal layer.

[0138] [Appendix 9] 9. The projector according to claim 3, a holding frame that is separate from the heat transfer frame and that is combined with the heat transfer frame to accommodate the liquid crystal layer, the incident-side substrate, the output-side substrate, the incident-side dustproof substrate, and the output-side dustproof substrate; A projector characterized by: According to this configuration, by combining the heat transfer frame and the holding frame, the liquid crystal layer, the incident side substrate, the exit side substrate, the incident side dustproof substrate, and the exit side dustproof substrate can be held, thereby protecting the liquid crystal layer, the incident side substrate, the exit side substrate, the incident side dustproof substrate, and the exit side dustproof substrate. Furthermore, because the heat transfer frame is separate from the holder frame, it can be configured to fit the shape of the incident-side dustproof substrate, thereby increasing the contact area with the incident-side dustproof substrate and improving the efficiency of heat transfer between the heat transfer frame and the incident-side dustproof substrate.

[0139] [Appendix 10] 10. The projector according to claim 3, The heat transfer frame is a first surface facing the light incident side; an opening through which light incident on the incident-side dustproof substrate passes; an airflow guide surface that extends along the first surface in a direction away from the opening and guides cooling air to the entrance-side dustproof substrate exposed through the opening, A projector characterized by: With this configuration, the air guide surface can guide the cooling air to the entrance-side dustproof substrate exposed within the opening, thereby cooling the entrance-side dustproof substrate to which heat from the liquid crystal layer is transmitted via the entrance-side substrate, and ultimately cooling the liquid crystal layer.

[0140] [Appendix 11] 11. The projector according to claim 10, When the dimension of the wind guide surface in the wind guide direction along the wind guide surface toward the opening is L, the intersection angle between the wind guide surface and the extension plane of the first surface is θ, the dimension of the opening in the wind guide direction is x, the dynamic viscosity coefficient of air is v, and the wind speed of the air flow flowing in the wind guide direction is U, the following formula 2 is satisfied: A projector characterized by: L×tanθ≦10×(4.91x 1 / 2 ×(v / U) 1 / 2 )…(2) By satisfying formula 1, it is possible to set the crossing angle θ and the dimension L that allow the airflow to efficiently flow toward the incident-side dustproof substrate exposed in the opening. Therefore, it is possible to reduce the size of the optical modulation device while improving the cooling efficiency of the liquid crystal layer.

[0141] [Appendix 12] 12. The projector according to claim 3, a temperature sensor provided in the light modulation device and configured to detect the temperature of the liquid crystal layer; a fan for circulating a cooling gas through the optical modulation device; a control unit that controls the heating element and the fan based on the temperature of the liquid crystal layer detected by the temperature sensor. A projector characterized by: With this configuration, the driving state of the heating element that heats the liquid crystal layer and the driving state of the fan that circulates the cooling gas that cools the liquid crystal layer can be controlled according to the temperature of the liquid crystal layer. This makes it possible to maintain the temperature of the liquid crystal layer within a temperature range that is suitable for driving the liquid crystal layer, for example. Therefore, the responsiveness of the liquid crystal layer can be maintained.

[0142] [Appendix 13] A liquid crystal layer; an incident-side substrate located on the light incident side with respect to the liquid crystal layer; an emission-side substrate located on the light emission side of the liquid crystal layer and sandwiching the liquid crystal layer together with the incident-side substrate; an incident-side dustproof substrate that is light-transmitting and positioned on the light incident side of the incident-side substrate; an exit-side dustproof substrate that has light transmissivity, is located on the light exit side of the exit-side substrate, and sandwiches the liquid crystal layer, the entrance-side substrate, and the exit-side substrate together with the entrance-side dustproof substrate; a temperature control unit for controlling the temperature of the liquid crystal layer, the plane size of the incident-side dustproof substrate is larger than the plane size of the incident-side substrate; the temperature control unit is in contact with the incident-side dust-proof substrate; An optical modulation device characterized by: By employing such a light modulation device in a projector, it is possible to achieve the same effects as the above-described projector. [Explanation of symbols]

[0143] 1...projector, 3...image projection device, 31...light source, 33, 33A...image forming device, 34, 34B, 34G, 34R...light modulation device, 36...light path changing element, 361...optical member, 362...first holding member (holding member), 363...second holding member (holding member), 364...base, 365...first actuator (actuator), 366...second actuator (actuator), 38...light path changing element, 382...holding member, 383...base, 384...actuator, 4...panel module, 41...liquid crystal panel, 41B...blue liquid crystal panel, 41G...green liquid crystal panel, 41R...red liquid crystal panel, 42...panel body, 421...optical action portion, 422...liquid crystal layer, 423...incident side substrate, 424...output side substrate, 425...input side dustproof substrate, 426...output side dustproof substrate, 43...FPC, 44...holding frame, 45...temperature control unit, 46...heat transfer frame, 46B...surface (light output side surface), 461...opening, 462...contact portion, 463...arrangement portion, 464...air guide portion, 464A...air guide surface, 465...heat dissipation portion, 47...heat generating element , 471...passage opening, 472, 473...electrode portion, 48...cover member, 481...cover portion, 482...opening, 483...absorption layer, 484...engagement portion, 6...cooling device, 61, 62...fan, 63...duct, 64...first duct portion, 65...second duct portion, 7...control device, 71, 71B, 71G, 71R...temperature sensor, 72...memory portion, 73...control portion.

Claims

1. A light source and a light modulation device that modulates the light emitted from the light source, The optical modulation device A liquid crystal layer; an incident-side substrate located on the light incident side with respect to the liquid crystal layer; an emission-side substrate located on the light emission side of the liquid crystal layer and sandwiching the liquid crystal layer together with the incident-side substrate; an incident-side dustproof substrate that is light-transmitting and positioned on the light incident side of the incident-side substrate; an exit-side dustproof substrate that has light transmissivity, is located on the light exit side of the exit-side substrate, and sandwiches the liquid crystal layer, the entrance-side substrate, and the exit-side substrate together with the entrance-side dustproof substrate; a temperature control unit for controlling the temperature of the liquid crystal layer; a planar size of the incident-side dustproof substrate as viewed from the light incident side of the optical modulation device is larger than a planar size of the incident-side substrate; The temperature control unit a heat transfer frame in contact with the incident-side dustproof substrate; a heating element provided on the heat transfer frame, A projector characterized by:

2. The projector according to claim 1 , the thermal conductivity of the incident-side dust-proof substrate is equal to or greater than the thermal conductivity of the incident-side substrate; A projector characterized by:

3. 3. The projector according to claim 1, the heat transfer frame has a recessed portion that faces the incident-side dustproof substrate and has an arrangement portion in which the heating element is arranged. A projector characterized by:

4. 3. The projector according to claim 1, the heat generating element is configured in a frame shape having a passage opening through which light incident on the incident-side dustproof substrate passes; A projector characterized by:

5. 3. The projector according to claim 1, an optical path changing element that changes the optical path of the light modulated by the optical modulation device; The optical path changing element is an optical member onto which the light modulated by the optical modulation device is incident; a holding member for holding the optical member; an actuator that swings the holding member, the light modulation device has a modulation region that modulates incident light, the modulation area has a rectangular shape having short sides and long sides when viewed from the light incident side, The heating element is disposed at a position different from the actuator in a direction along the short side. A projector characterized by:

6. 3. The projector according to claim 1, the temperature control unit is provided on the opposite side of the heat transfer frame with respect to the heat generating element, and includes a cover member that covers at least a portion of the heat generating element; The thermal conductivity of the cover member is lower than the thermal conductivity of the heat transfer frame. A projector characterized by:

7. The projector according to claim 6 , the cover member has an absorption layer provided on a light incident side surface of the cover member and absorbing visible light; A projector characterized by:

8. 3. The projector according to claim 1, a holding frame that is separate from the heat transfer frame and that is combined with the heat transfer frame to accommodate the liquid crystal layer, the incident-side substrate, the output-side substrate, the incident-side dustproof substrate, and the output-side dustproof substrate; A projector characterized by:

9. 3. The projector according to claim 1, The heat transfer frame is a first surface facing the light incident side; an opening through which light incident on the incident-side dustproof substrate passes; an airflow guide surface extending along the first surface in a direction away from the opening and guiding cooling air to the entrance-side dustproof substrate exposed through the opening; A projector characterized by:

10. The projector according to claim 9, When the dimension of the airflow direction along the airflow surface toward the opening is defined as L, the intersection angle between the airflow surface and the extension plane of the first surface is defined as θ, the dimension of the opening in the airflow direction is defined as x, the dynamic viscosity coefficient of air is defined as v, and the wind speed of the airflow flowing in the airflow direction is defined as U, the following formula 1 is satisfied: A projector characterized by: L×tanθ≦10×(4.91×1 / 2×(v / U)1 / 2)…(1)

11. 3. The projector according to claim 1, a temperature sensor provided in the light modulation device and configured to detect the temperature of the liquid crystal layer; a fan for circulating a cooling gas through the optical modulation device; a control unit that controls the heating element and the fan based on the temperature of the liquid crystal layer detected by the temperature sensor. A projector characterized by:

12. A liquid crystal layer; an incident-side substrate located on the light incident side with respect to the liquid crystal layer; an emission-side substrate located on the light emission side of the liquid crystal layer and sandwiching the liquid crystal layer together with the incident-side substrate; an incident-side dustproof substrate that is light-transmitting and positioned on the light incident side of the incident-side substrate; an exit-side dustproof substrate that has light transmissivity, is located on the light exit side of the exit-side substrate, and sandwiches the liquid crystal layer, the entrance-side substrate, and the exit-side substrate together with the entrance-side dustproof substrate; a temperature control unit for controlling the temperature of the liquid crystal layer, the plane size of the incident-side dustproof substrate is larger than the plane size of the incident-side substrate; The temperature control unit a heat transfer frame in contact with the incident-side dustproof substrate; a heating element provided on the heat transfer frame, An optical modulation device characterized by:

Images