Projector and projection system

Abstract

To accurately adjust a projection image based on a movement amount in a projector.SOLUTION: A projector includes: a visible light source device that emits visible light containing first light having a first wavelength; an invisible light source device that emits invisible light; a first light combining element that combines the first light and the invisible light into first combined light; a first liquid crystal panel that modulates the first combined light; a first incident-side polarizing plate that transmits the first light between the visible light source device and the first light combining element; a first emission-side polarizing plate that transmits the first combined light at a light emission side of the first liquid crystal panel; and a projection optical system that projects the first combined light emitted from the first liquid crystal panel.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a projector and a projection system. [Background technology]

[0002] In image display devices such as projectors, in order to control the visible image to be displayed, a visible image and an invisible image such as an infrared image are superimposed on a screen, and control is sometimes performed based on information obtainable from the invisible image. For example, Patent Document 1 discloses a projector that separates infrared light from light emitted from a light source and superimposes it on a projected image via a dedicated light modulation element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-176195 Summary of the Invention [Problem to be solved by the invention]

[0004] In the device disclosed in the aforementioned Patent Document 1, the optical path of invisible light is positioned at a different position from the optical path of visible light, which means that movement or deviation of the projected image caused by factors on the optical path of each color of visible light cannot be accurately reproduced on the optical path of invisible light, making it difficult to accurately adjust the projected image. [Means for solving the problem]

[0005] In order to solve the above problem, one embodiment of the projector of the present invention includes a visible light source device that emits visible light including a first light of a first wavelength, an invisible light source device that emits invisible light, a first light combining element that combines the first light and the invisible light to form first combined light, a first liquid crystal panel that modulates the first combined light, a first incident side polarizing plate that transmits the first light between the visible light source device and the first light combining element, a first exit side polarizing plate that transmits the first combined light on the light exit side of the first liquid crystal panel, and a projection optical system that projects the first combined light emitted from the first liquid crystal panel.

[0006] A projection system according to one embodiment of the present invention comprises the projector and an imaging device that captures a projection image of invisible light projected from the projector, wherein the projector is equipped with a movement mechanism that moves the projection optical system to change the position of the projection image, and a control unit that controls the movement mechanism based on the image captured by the imaging device.

[0007] A projection system according to one embodiment of the present invention comprises the projector and an imaging device that captures a projection image of invisible light projected from the projector, and the projector is equipped with a control unit that changes the area of ​​the image formed in the image display area of ​​the first liquid crystal panel based on the image captured by the imaging device. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a projector according to an embodiment. [Figure 2] FIG. 2 is a schematic plan view of a light-transmitting member according to an embodiment. [Figure 3] FIG. 2 is a cross-sectional view of a light-transmitting member according to an embodiment. [Figure 4] 10 is a conceptual diagram illustrating the polarization state of first combined light in a projector according to an embodiment. FIG. [Figure 5] FIG. 2 is a schematic diagram illustrating the positional relationship between a projection optical system, a first liquid crystal panel, and a light-transmitting member in a projector according to an embodiment. [Figure 6] 10 is a schematic plan view of a light-transmitting member according to Modification 1. FIG. [Figure 7] FIG. 10 is a schematic diagram of a projector according to a second modification. [Figure 8] FIG. 10 is a cross-sectional view schematically illustrating a depolarization plate used in a projector according to a second modification. [Figure 9] 10 is a schematic diagram of a first laser light source and a second laser light source that can be employed in Modification 2. FIG. [Figure 10] 10 is a diagram showing the polarization state of light emitted from the light-emitting region shown in FIG. 9 on the Poincare sphere. FIG. [Figure 11] FIG. 10 is a schematic diagram of a projector according to a third modification. [Figure 12] FIG. 10 is a schematic diagram of a projector according to a fourth modification. [Figure 13] FIG. 10 is a schematic diagram showing a projection system of Modification 5, showing a projected image in the initial state or after image correction has been performed. [Figure 14] FIG. 13 is a schematic diagram showing a projection system according to a fifth modification, illustrating a projected image before image correction is performed. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a schematic diagram showing the configuration of a projection system 16 according to one embodiment. In the following drawings, the dimensions of some components may be reduced to different scales to make them easier to see.

[0010] (Projection System) The projection system 16 includes a projector 15 and an imaging device 710. The projector 15 projects a projected image Px of infrared light I containing a predetermined pattern F and a projected image P of visible light, which are superimposed on each other, onto a screen SCR disposed in front of the projector 15. The configuration of the projector 15 will be described in detail later.

[0011] The imaging device 710 is, for example, a camera having an imaging element capable of capturing infrared light I. The imaging device 710 is disposed outside the projector 15 and is connected to the projector 15 by wire or wirelessly. It is disposed in a location that does not block the light projected from the projector 15. The imaging device 710 may also be incorporated inside the projector 15.

[0012] The imaging device 710 captures the projection image P projected by the projector 15. As will be described later, the projection image P is composed of second combined light C2, which is a combination of visible light and invisible infrared light I. Therefore, a projection image Px of the infrared light I is superimposed on the projection image P. The imaging device 710 captures the projection image Px of the infrared light I. A control unit 730 of the projector 15 is connected to the imaging device 710. The control unit 730 corrects the position of the projection image P based on the projection image Px of the infrared light I captured by the imaging device 710.

[0013] In this specification, visible light refers to light having a wavelength of, for example, 360 nm or more and 830 nm or less. Invisible light refers to, for example, ultraviolet light having a wavelength of less than 360 nm or red light having a wavelength of more than 830 nm. In this embodiment, a case where infrared light I is used as invisible light will be described, but ultraviolet light may also be used as invisible light.

[0014] (projector) As shown in FIG. 1, the projector 15 includes a visible light source device 20, an invisible light source device 150, a color separation optical system 200, field lenses 300R, 300G, and 300B, liquid crystal panels 400R, 400G, and 400B, incident-side polarizing plates 410R, 410G, and 410B, exit-side polarizing plates 420R, 420G, and 420B, a light-transmitting member 505, a cross dichroic prism (second light combining element) 500, a projection optical system 600, a moving mechanism 720, and a control unit 730.

[0015] In the following description, when distinguishing between the multiple liquid crystal panels 400R, 400G, and 400B, they are referred to as the first liquid crystal panel 400G, the second liquid crystal panel 400R, and the third liquid crystal panel 400B, respectively. When distinguishing between the multiple incident-side polarizing plates 410R, 410G, and 410B, they are referred to as the first incident-side polarizing plate 410G, the second incident-side polarizing plate 410R, and the third incident-side polarizing plate 410B, respectively. When distinguishing between the multiple exit-side polarizing plates 420R, 420G, and 420B, they are referred to as the first exit-side polarizing plate 420G, the second exit-side polarizing plate 420R, and the third exit-side polarizing plate 420B, respectively.

[0016] (Visible light source device) The visible light source device 20 emits white light WL that is synthesized from red light R, green light G, and blue light B, which are visible light. In this embodiment, the green light G is first light with a first wavelength. The red light R is second light with a second wavelength that is different from the first wavelength. The blue light B is third light with a third wavelength that is different from both the first wavelength and the second wavelength. The first wavelength may be within a wavelength range that is visible as green light G, the second wavelength may be within a wavelength range that is visible as red light R, and the third wavelength may be within a wavelength range that is visible as blue light.

[0017] The visible light source device 20 includes a light source unit 100, a first lens array 70, a second lens array 80, a polarization conversion element 92, and a superimposing lens 94. The light source unit 100 emits white light WL. The white light WL emitted from the light source unit 100 is collimated and enters the first lens array 70.

[0018] The first lens array 70 has a plurality of small lenses 71 for dividing the white light WL emitted from the light source unit 100 into a plurality of partial light beams. The plurality of small lenses 71 are arranged in a matrix in a plane perpendicular to the optical axis AX20 of the light source unit 100.

[0019] The second lens array 80 has a plurality of small lenses 81 corresponding to the plurality of small lenses 71 of the first lens array 70. The plurality of small lenses 81 are arranged in a matrix in a plane perpendicular to the optical axis AX20. The second lens array 80, together with the superimposing lens 94, forms an image of each small lens 71 of the first lens array 70 near the image forming area of ​​each of the liquid crystal panels 400R, 400G, and 400B.

[0020] The polarization conversion element 92 includes a polarization separation layer, a reflection layer, and a retardation plate (not shown). The polarization conversion element 92 converts the partial light beams emitted from the second lens array 80 into linearly polarized light. The polarization conversion element 92 is generally formed in a plate shape. The plate surface of the polarization conversion element 92 is arranged parallel to a plane perpendicular to the optical axis AX20. The polarization separation layer of the polarization conversion element 92 transmits one linearly polarized component of the polarization components contained in the partial light beams emitted from the second lens array 80 and reflects the other linearly polarized component in a direction perpendicular to the optical axis AX20. The reflection layer of the polarization conversion element 92 reflects the other linearly polarized component reflected by the polarization separation layer in a direction parallel to the optical axis AX20. The retardation plate of the polarization conversion element 92 converts the other linearly polarized component reflected by the reflection layer into one linearly polarized component.

[0021] The superimposing lens 94 collects the partial light beams from the polarization conversion element 92 and superimposes them near the image forming areas of the liquid crystal panels 400R, 400G, and 400B. The first lens array 70, the second lens array 80, and the superimposing lens 94 constitute an integrator optical system. The integrator optical system homogenizes the in-plane light intensity distribution of the white light WL emitted from the visible light source device 20 in the image forming areas of the liquid crystal panels 400R, 400G, and 400B.

[0022] (Invisible light source device) The invisible light source device 150 emits, as invisible light, for example, infrared light I. Note that the invisible light source device 150 may also emit ultraviolet light as invisible light.

[0023] The invisible light source device 150 includes a substrate 150b, a plurality of light emitting diode light sources 150a mounted on the substrate 150b, and a condenser lens (homogenizing optical element) 153.

[0024] The light emitting diode light source 150a is a light emitting diode (LED) that emits infrared light I. The plurality of light emitting diode light sources 150a are arranged in a plane perpendicular to the optical axis of the infrared light I. Note that the invisible light source device 150 may have only a single light emitting diode light source 150a. In this case, the light emitting diode light source 150a is arranged on the optical axis of the infrared light I.

[0025] In this embodiment, the wavelength of the infrared light I emitted by the light-emitting diode light source 150a is 930 nm or more and 950 nm or less. In this case, the projector 15 projects a projection image Px of the infrared light I with a wavelength of 930 nm or more and 950 nm or less onto the screen SCR. Among light in the near-infrared region contained in sunlight, light with a wavelength of around 940 nm has low energy. In other words, the amount of infrared light I with a wavelength of around 940 nm in sunlight is less than that of light with other wavelengths. According to this embodiment, by using light with a wavelength of around 940 nm, that is, between 930 nm and 950 nm or less, as the infrared light I, it is possible to prevent a decrease in the contrast of the pattern F of the infrared light I due to the influence of sunlight when the infrared light I is irradiated onto the screen SCR. As a result, it is possible to prevent a decrease in the accuracy of position detection using the pattern F of the infrared light I.

[0026] In this embodiment, the wavelength of the infrared light I emitted by the light-emitting diode light source 150a may be 840 nm or more and 860 nm or less. In this case, the projector 15 projects a projection image Px of the infrared light I having a wavelength of 840 nm or more and 860 nm or less onto the screen SCR. Generally, the wavelength of light that humans can perceive is 360 nm or more and 830 nm or less. Therefore, by using the infrared light I having a wavelength of 840 nm or more and 860 nm or less as invisible light, it is not perceived by viewers. Furthermore, light sources using light-emitting diodes or lasers can emit light with higher efficiency, the closer it is to visible light. According to this embodiment, by using light having a wavelength of 840 nm or more and 860 nm or less as the infrared light I, the energy efficiency of the invisible light source device 150 can be improved, and the power consumption of the projector 15 can be reduced. Furthermore, since light sources that emit infrared light I of 840 nm or more and 860 nm or less are widely used as light sources of invisible light, parts can be procured cheaply and stably, which allows for a reduction in the manufacturing cost of projector 15.

[0027] The condenser lens 153 is disposed on the light emission side of the light-emitting diode light source 150a. The condenser lens 153 may be, for example, a single convex meniscus lens or multiple convex meniscus lenses. The convex meniscus lens is preferably an aspherical lens molded from glass or resin to improve light-collecting performance. The condenser lens 153 transmits the infrared light I emitted from the light-emitting diode light source 150a and uniforms the amount of light of the infrared light I within its plane.

[0028] In this embodiment, the case where the condenser lens 153 is used as the uniformizing optical element has been described. However, the configuration of the uniformizing optical element is not limited to this embodiment. For example, a diffractive optical element (DOE) such as a holographic optical element (HOE) may be used as the uniformizing optical element. In this case, the diffractive optical element serving as the uniformizing optical element has a surface pattern formed thereon to form a uniform irradiation pattern, and diffracts the infrared light I passing through it to uniformize the amount of light in the plane of the infrared light I. When a diffractive optical element is used as the uniformizing optical element, a laser light source is used as the light source that emits the infrared light I.

[0029] (color separation optical system) The color separation optical system 200 includes dichroic mirrors 210 and 220 and reflecting mirrors 230, 240, and 250. The color separation optical system 200 separates the white light WL emitted from the visible light source device 20 into red light R, green light G, and blue light B, which are visible light, and guides each of the red light R, green light G, and blue light B to the liquid crystal panels 400R, 400G, and 400B, respectively. Infrared light I is also introduced into the color separation optical system 200 of this embodiment and combined with the green light G. Therefore, a portion of the color separation optical system 200 of this embodiment also functions as a combining optical system that combines visible light and invisible light.

[0030] In the following description, when the multiple dichroic mirrors 210, 220 need to be distinguished from one another, they will be referred to as the first dichroic mirror 210 and the second dichroic mirror 220. Similarly, when the multiple reflecting mirrors 230, 240, 250 need to be distinguished from one another, they will be referred to as the first reflecting mirror 230, the second reflecting mirror 240, and the third reflecting mirror 250, respectively.

[0031] The first dichroic mirror 210 is disposed on the optical axis AX20 of the visible light source device 20 and facing the visible light source device 20. The white light WL emitted from the visible light source device 20 is incident on the first dichroic mirror 210. The first dichroic mirror 210 reflects red light R of the incident white light WL and transmits green light G and blue light B. In this way, the first dichroic mirror 210 separates the white light WL emitted from the visible light source device 20 into red light R, green light G, and blue light B.

[0032] The second dichroic mirror 220 is disposed on an extension of the optical axis AX20 of the visible light source device 20. The second dichroic mirror 220 is disposed on the optical axis AX150 of the invisible light source device 150 and faces the invisible light source device 150. In this embodiment, the optical axis AX20 of the visible light source device 20 and the optical axis AX150 of the invisible light source device 150 are perpendicular to each other. The second dichroic mirror 220 is installed at an angle of 45° with respect to both the optical axis AX20 of the visible light source device 20 and the optical axis AX150 of the invisible light source device 150. The second dichroic mirror 220 has a first surface 220a and a second surface 220b. The first surface 220a faces the invisible light source device 150. The second surface 220b faces the visible light source device 20.

[0033] The green light G and blue light B that have passed through the first dichroic mirror 210 are incident on the second surface 220b of the second dichroic mirror 220. The second dichroic mirror 220 reflects the green light G and transmits the blue light B. That is, the second dichroic mirror 220 emits the green light G from the second surface 220b and emits the blue light B from the first surface 220a. In this way, the second dichroic mirror 220 separates the green light G and the blue light B.

[0034] Furthermore, the infrared light I emitted from the invisible light source device 150 is incident on the first surface 220a of the second dichroic mirror 220. The second dichroic mirror 220 transmits the incident infrared light I. Therefore, the second dichroic mirror 220 emits the infrared light I from the second surface 220b.

[0035] The first reflecting mirror 230 and the second reflecting mirror 240 are disposed on the optical path of the blue light B. The first reflecting mirror 230 and the second reflecting mirror 240 reflect almost all of the incident blue light B. The third reflecting mirror 250 is disposed on the optical path of the red light R. The third reflecting mirror 250 reflects almost all of the incident red light R.

[0036] Red light R reflected by first dichroic mirror 210 is reflected by third reflecting mirror 250 and directed to second liquid crystal panel 400R. Green light G transmitted through first dichroic mirror 210 and reflected by second dichroic mirror 220 is directed to first liquid crystal panel 400G. Blue light B transmitted through first dichroic mirror 210 and second dichroic mirror 220 is reflected by first reflecting mirror 230 and second reflecting mirror 240 and directed to third liquid crystal panel 400B. Infrared light I transmitted through second dichroic mirror 220 is directed together with green light G to first liquid crystal panel 400G.

[0037] In this embodiment, the green light G and the infrared light I are combined by being emitted from the second surface 220b of the second dichroic mirror 220. That is, the second dichroic mirror 220 functions as a light combining element. Here, the combined light of the green light G and the infrared light I combined by the second dichroic mirror 220 is referred to as first combined light C1. The second dichroic mirror (first light combining element) 220 combines the green light G and the infrared light I to form the first combined light C1.

[0038] In this embodiment, the second dichroic mirror 220 is preferably provided with a film that cancels out the polarized light on the first surface 220a and the second surface 220b. A typical dichroic mirror imparts polarized light to the light that passes through it. According to the second dichroic mirror 220 of this embodiment, even if infrared light I passes through, the polarized light can be canceled out when the light passes through the second surface 220b after passing through the first surface 220a. Therefore, the infrared light I can maintain its unpolarized state even after passing through the second dichroic mirror 220.

[0039] The films formed on the first surface 220a and the second surface 220b are optical thin films. The film formed on the first surface 220a transmits infrared light I. The film formed on the second surface 220b reflects green light G and transmits infrared light I. In the second dichroic mirror 220 of this embodiment, the transmittance of the films formed on the first surface 220a and the second surface 220b for infrared light I incident at an incident angle of 30° to 60° is 90% or more. In the second dichroic mirror 220 of this embodiment, of the S-polarized and P-polarized infrared light I, the polarization that has a larger difference between the maximum transmittance and the minimum transmittance when the infrared light I is incident on the second dichroic mirror 220 at an incident angle of 30° to 60° is, for example, S-polarized light (first polarization). Furthermore, the transmittance of the films formed on the first surface 220a and the second surface 220b varies depending on the angle of incidence of the infrared light I. Here, when the transmittance of the infrared light I increases with increasing distance from the incident side, it is considered that the "slope of the incident angle dependency is positive." On the other hand, when the transmittance of the infrared light I decreases with increasing distance from the incident side, it is considered that the "slope of the incident angle dependency is negative." The second dichroic mirror 220 of this embodiment has a range of incident angles over which the slope of the incident angle dependency of the transmittance of the film formed on the second surface 220b for S-polarized infrared light I and the slope of the incident angle dependency of the transmittance of the film formed on the first surface 220a for S-polarized infrared light I are opposite in sign to each other. This range is, for example, 40° to 55°, including 45°. As described above, in the second dichroic mirror 220 of this embodiment, the range of incident angles has an inverse relationship between the positive and negative slopes of the incidence angle dependence of the transmittance of the film formed on the second surface 220b for S-polarized infrared light I and the positive and negative slopes of the incidence angle dependence of the transmittance of the film formed on the first surface 220a for S-polarized infrared light I, and polarization compensation is performed on the film formed on the first surface 220a.

[0040] (field lens) Field lenses 300R, 300G, and 300B are disposed on the optical paths of red light R, green light G, and blue light B, respectively, between color separation optical system 200 and liquid crystal panels 400R, 400G, and 400B. Red light R passes through field lens 300R and enters the image forming area of ​​second liquid crystal panel 400R. Green light G reflected by second dichroic mirror 220 passes through field lens 300G and enters the image forming area of ​​first liquid crystal panel 400G. Blue light B reflected by third reflecting mirror 250 passes through field lens 300B and enters the image forming area of ​​third liquid crystal panel 400B.

[0041] (Translucent member) The light-transmitting member 505 is disposed on the light incident surface side of the first liquid crystal panel 400G. The light-transmitting member 505 of this embodiment is disposed between the field lens 300G and the first liquid crystal panel 400G. The light-transmitting member 505 may be disposed on the optical path of the first combined light C1, between the second dichroic mirror 220 and the first exit-side polarizing plate 420G.

[0042] FIG. 2 is a plan view schematic diagram of the light-transmitting member 505 of this embodiment. The light-transmitting member 505 has shielding portions 511 and transmitting portions 512. The shielding portions 511 shield infrared light I by reflecting or absorbing it, and transmit visible light (particularly green light G in this embodiment). On the other hand, the transmitting portions 512 transmit both infrared light I and visible light. In this embodiment, the transmitting portions 512 are arranged in a predetermined pattern F. In this embodiment, the predetermined pattern F of the transmitting portions 512 is a dotted pattern. Therefore, the infrared light I passing through the light-transmitting member 505 includes the dotted predetermined pattern F. On the other hand, the visible light passing through the light-transmitting member 505 is not blocked by the light-transmitting member 505, and the pattern F does not change before and after passing through.

[0043] FIG. 3 is a schematic cross-sectional view of the light-transmitting member 505 of this embodiment. The light-transmitting member 505 of this embodiment is plate-shaped and has an incident surface 505f onto which the green light G and the infrared light I are incident. The light-transmitting member 505 of this embodiment also has a base material 505a, an anti-reflection film 505b, and a shielding film 505c.

[0044] The base material 505a is made of, for example, quartz glass. The base material 505a transmits both visible light and infrared light. The anti-reflection film 505b is formed on the entire surface of the base material 505a on the side of the incident surface 505f. The anti-reflection film 505b prevents reflection of light incident from the surface.

[0045] The shielding film 505c is partially formed on the antireflection film 505b on the incident surface 505f side of the base material 505a. The shielding film 505c in this embodiment is an infrared light reflective film. Therefore, the shielding film 505c reflects infrared light I and transmits visible light (particularly green light G in this embodiment). Note that the shielding film 505c may also be one that blocks infrared light I by absorbing the infrared light I. In other words, the shielding film 505c may be one that blocks infrared light I and transmits visible light.

[0046] In the light-transmitting member 505 of this embodiment, the region where the shielding film 505c is formed functions as a shielding portion 511, and the other region functions as a transmitting portion 512. Therefore, in the light-transmitting member 505 of this embodiment, the region where the shielding film 505c is not formed forms a predetermined dot-shaped pattern F.

[0047] In the method for manufacturing the light-transmitting member 505, first, the antireflection film 505b is vapor-deposited on the surface of the base material 505a on the side of the incident surface 505f. Next, the shielding film 505c is formed by a metal mask method. In the metal mask method, the shielding film 505c is vapor-deposited on the surface of the antireflection film 505b through a metal mask having holes formed therein that correspond to a predetermined pattern F. When the metal mask method is used as the method for forming the shielding film 505c, it is sufficient to vapor-deposit the shielding film 505c only in the areas other than the predetermined pattern F. The metal mask method has the advantages of easily increasing the precision of the metal mask and of high productivity of the metal mask.

[0048] Alternatively, the shielding film 505c may be formed by a lift-off method. In the lift-off method, first, a resist is applied to the surface of the antireflection film 505b, and then the resist is exposed and developed using a photomask aligned with a predetermined pattern F, and the shielding film 505c is vapor-deposited on top of the remaining resist. Finally, the remaining resist is removed, leaving only the shielding film 505c formed directly on the antireflection film 505b.

[0049] (LCD panel) Each of the liquid crystal panels 400R, 400G, and 400B forms an image by modulating incident red light R, green light G, and blue light B in accordance with image information. The operation mode of the liquid crystal panels is not limited to a specific mode and may be any of TN mode, VA mode, transverse electric field mode, etc.

[0050] The first combined light C1 (i.e., green light G and infrared light I) is incident on the first liquid crystal panel 400G. The first liquid crystal panel 400G modulates the first combined light C1. The first liquid crystal panel 400G modulates at least the green light G of the first combined light C1. The second liquid crystal panel 400R is incident on the second liquid crystal panel 400R. The second liquid crystal panel 400R modulates the red light R. The third liquid crystal panel 400B is incident on the blue light B. The third liquid crystal panel 400B modulates the blue light B. In this embodiment, the liquid crystal panels 400R, 400G, and 400B modulate P-polarized light to S-polarized light in the OFF region. On the other hand, they transmit P-polarized light as is (as P-polarized light) in the ON region.

[0051] (polarizing plate) The first incident-side polarizing plate 410G is disposed on the light incident surface side of the first liquid crystal panel 400G. The first incident-side polarizing plate 410G may be disposed on the optical path of the green light G between the visible light source device 20 and the second dichroic mirror 220. The first incident-side polarizing plate 410G transmits the green light G and the blue light B on the light incident side of the first liquid crystal panel 400G. The first incident-side polarizing plate 410G P-polarizes the green light G that has been P-polarized by the polarization conversion element 92 and whose polarization has been disturbed in the optical path.

[0052] The first exit-side polarizing plate 420G is disposed on the light exit surface side of the first liquid crystal panel 400G. The first exit-side polarizing plate 420G may be disposed on the optical path of the first combined light C1 between the first liquid crystal panel 400G and the cross dichroic prism 500. The first exit-side polarizing plate 420G transmits the first combined light C1 on the light exit side of the first liquid crystal panel 400G. The first exit-side polarizing plate 420G transmits S-polarized green light G and limits transmission of P-polarized green light G.

[0053] The second incident-side polarizing plate 410R is disposed on the light incident surface side of the second liquid crystal panel 400R. The second incident-side polarizing plate 410R may be disposed on the optical path of the red light R, between the first dichroic mirror 210 and the second liquid crystal panel 400R. The second incident-side polarizing plate 410R transmits the red light R on the light incident side of the second liquid crystal panel 400R. The second incident-side polarizing plate 410R P-polarizes the red light R that has been P-polarized by the polarization conversion element 92 and whose polarization has been disturbed in the optical path. In other words, the second incident-side polarizing plate 410R transmits the P-polarized red light R and limits the transmission of the S-polarized red light R.

[0054] The second exit-side polarizing plate 420R is disposed on the light exit surface side of the second liquid crystal panel 400R. The second exit-side polarizing plate 420R may be disposed on the optical path of the red light R between the second liquid crystal panel 400R and the cross dichroic prism 500. The second exit-side polarizing plate 420R transmits the red light R on the light exit side of the second liquid crystal panel 400R. The second exit-side polarizing plate 420R transmits S-polarized red light R and limits the transmission of P-polarized red light R.

[0055] The third incident-side polarizing plate 410B is disposed on the light incident surface side of the third liquid crystal panel 400B. The third incident-side polarizing plate 410B may be disposed on the optical path of the blue light B between the first dichroic mirror 210 and the third liquid crystal panel 400B. The third incident-side polarizing plate 410B transmits the blue light B on the light incident side of the third liquid crystal panel 400B. The third incident-side polarizing plate 410B P-polarizes the blue light B that has been P-polarized by the polarization conversion element 92 and whose polarization has been disturbed along the optical path. In other words, the third incident-side polarizing plate 410B transmits the P-polarized blue light B and limits the transmission of the S-polarized blue light B.

[0056] In this embodiment, a first incident-side polarizing plate 410G is disposed in the optical path of the blue light B. Therefore, the blue light B passes through the first incident-side polarizing plate 410G and becomes P-polarized. However, in this embodiment, the blue light B is repeatedly reflected by multiple reflecting mirrors 230 and 240 on its way from the first incident-side polarizing plate 410G to the third liquid crystal panel 400B, which may cause polarization disturbance. Therefore, according to this embodiment, the third incident-side polarizing plate 410B is disposed between the reflecting mirror 240 and the third liquid crystal panel 400B, and the polarization of the blue light B can be adjusted by transmitting the blue light B. This allows the blue light B to be incident on the third liquid crystal panel 400B as P-polarized light with less disturbance.

[0057] The third exit-side polarizing plate 420B is disposed on the light exit surface side of the third liquid crystal panel 400B. The third exit-side polarizing plate 420B may be disposed on the optical path of the blue light B between the third liquid crystal panel 400B and the cross dichroic prism 500. The third exit-side polarizing plate 420B transmits the blue light B on the light exit side of the third liquid crystal panel 400B. The third exit-side polarizing plate 420B transmits S-polarized blue light B and limits the transmission of P-polarized blue light B.

[0058] In this embodiment, the first incident-side polarizer 410G, the first exit-side polarizer 420G, the second incident-side polarizer 410R, the second exit-side polarizer 420R, the third incident-side polarizer 410B, and the third exit-side polarizer 420B are inorganic polarizers such as wire grid polarizers.

[0059] 4 is a conceptual diagram illustrating the polarization state of the first combined light C1 before and after the first liquid crystal panel 400G. The polarization states of the green light G and the infrared light I are represented by arrows and circles. The arrows represent P-polarized light, and the circles represent S-polarized light. The area where the arrows and circles overlap indicates a state in which both P-polarized light and S-polarized light are included.

[0060] As shown in FIG. 4, green light G passes through first incident-side polarizing plate 410G before entering second dichroic mirror 220. Second dichroic mirror 220 blocks S-polarized green light G and transmits P-polarized green light G. The P-polarized green light G emitted from first incident-side polarizing plate 410G is reflected by second dichroic mirror 220 and combined with infrared light I to form first combined light C1. Furthermore, green light G included in first combined light C1 passes through translucent member 505 and further enters first liquid crystal panel 400G. First liquid crystal panel 400G modulates P-polarized green light G to S-polarized light in the OFF region and transmits P-polarized green light G as is in the ON region. When green light G emitted from first liquid crystal panel 400G passes through first exit-side polarizing plate 420G, it blocks S-polarized light and transmits only P-polarized light. As a result, only the light that has passed through the ON region of the first liquid crystal panel 400G is incident on the cross dichroic prism 500 as image light.

[0061] On the other hand, the infrared light I passes through the second dichroic mirror 220 and is combined with the green light G to form the first combined light C1. Furthermore, when the infrared light I contained in the first combined light C1 passes through the light-transmitting member 505, a portion of the light is blocked by the blocking portion 511 of the light-transmitting member 505, thereby forming a pattern F, and then the infrared light I enters the first liquid crystal panel 400G.

[0062] When infrared light I enters the ON region of the first liquid crystal panel 400G, P-polarized light and S-polarized light are transmitted as they are. When infrared light I enters the OFF region of the first liquid crystal panel 400G, the P-polarized light and S-polarized light are reversed and transmitted. More specifically, in the OFF region, the first liquid crystal panel 400G modulates P-polarized infrared light I to S-polarized light and S-polarized infrared light I to P-polarized light. That is, the P-polarized light and S-polarized light of the infrared light I are reversed before and after passing through the first liquid crystal panel 400G. In this embodiment, the infrared light I entering the first liquid crystal panel 400G is in an unpolarized state, so even if the P-polarized light and S-polarized light are reversed, the unpolarized state is maintained, and it appears that only the P-polarized light and S-polarized light are transmitted as they are. That is, when infrared light I enters the first liquid crystal panel 400G, P-polarized light and S-polarized light are transmitted through the first liquid crystal panel 400G in both the ON and OFF regions and enter the first exit-side polarizer 420G.

[0063] Because the infrared light I entering the first liquid crystal panel 400G is unpolarized, both P-polarized and S-polarized light are transmitted through the first exit-side polarizer 420G in both the ON and OFF regions, and enter the first exit-side polarizer 420G. The infrared light I passing through the first exit-side polarizer 420G blocks polarized light and transmits only P-polarized light, uniformly reducing the amount of light in the irradiation plane by approximately half. This allows the infrared light I that passes through both the ON and OFF regions of the first liquid crystal panel 400G to enter the cross dichroic prism 500. Therefore, the pattern F of the infrared light I formed in the light-transmitting member 505 is not affected by the first liquid crystal panel 400G, and the infrared light I forming the pattern F can enter the cross dichroic prism 500 as is.

[0064] (cross dichroic prism) 1, cross dichroic prism 500 combines the image light beams emitted from liquid crystal panels 400R, 400G, and 400B to form a color image. Cross dichroic prism 500 of the present embodiment combines first combined light beam C1 emitted from first liquid crystal panel 400G, red light beam R emitted from second liquid crystal panel 400R, and blue light beam B emitted from third liquid crystal panel 400B to form second combined light beam C2. Second combined light beam C2 combined by cross dichroic prism 500 includes infrared light beam I in addition to red light beam R, green light beam G, and blue light beam B.

[0065] The cross dichroic prism 500 is formed in a generally cubic shape as a whole by arranging four rectangular prisms so that their apexes overlap a common center position in a side view. A dielectric multilayer film (not shown) is formed at the interface where the rectangular prisms in the cross dichroic prism 500 are bonded together. The interface is generally X-shaped in a side view.

[0066] (Projection optical system) The projection optical system 600 faces the screen SCR. The projection optical system 600 enlarges and projects an image formed by the second combined light emitted from the cross dichroic prism 500, to form projected images P, Px on the screen SCR. Although not shown, the projection optical system 600 is composed of multiple lenses.

[0067] Fig. 5 is a schematic diagram illustrating the positional relationship between the projection optical system 600, the first liquid crystal panel 400G, and the light-transmitting member 505. Note that Fig. 5 does not illustrate the cross dichroic prism 500 and the first exit-side polarizing plate 420G, which are disposed between the projection optical system 600 and the first liquid crystal panel 400G.

[0068] The projection optical system 600 forms imaging planes 601 and 602 on the side opposite to the projection direction. In the following description, the imaging plane of the projection optical system 600 using green light G will be referred to as the green light imaging plane 601, and the imaging plane of the projection optical system 600 using infrared light I will be referred to as the infrared light imaging plane 602. The optical path length from the projection optical system 600 to the image formation surfaces 601 and 602 differs for each wavelength due to the influence of chromatic aberration of the projection optical system 600. For this reason, the green light image formation surface 601 and the infrared light image formation surface 602 are arranged offset from each other on the optical path of the first combined light C1.

[0069] The green light image forming surface 601 overlaps the first liquid crystal panel 400G. More specifically, the image forming surface 601 overlaps the liquid crystal panel main body 400a of the first liquid crystal panel 400G. This allows the image of the green light G formed on the first liquid crystal panel 400G to be clearly projected onto the screen SCR through the projection optical system 600.

[0070] On the other hand, the infrared light imaging plane 602 is offset from the light-transmissive member 505 in the axial direction of the optical path of the first combined light C1. The infrared light imaging plane 602 of this embodiment is offset from the light-transmissive member 505 toward the side where the first liquid crystal panel 400G is arranged.

[0071] Because the infrared light imaging plane 602 is misaligned with respect to the light-transmitting member 505, the image of the pattern F of the infrared light I formed by transmission through the light-transmitting member 505 is not in focus on the screen SCR. For this reason, when the dot-shaped pattern F is formed using the light-transmitting member 505, the image projected onto the screen SCR by the projection optical system 600 has an illuminance distribution close to a Gaussian distribution, in which the illuminance gradually decreases from the center of the dot toward the outside.

[0072] As shown in FIG. 1, the pattern F of infrared light I projected onto the screen SCR is captured by the imaging device 710 and used for image alignment in the control unit 730. Here, the pattern F of infrared light I captured by the imaging device 710 preferably has a Gaussian distribution on the screen SCR. In this case, the position of the image light can be recognized with high accuracy by detecting the center of gravity of the dot-shaped pattern F. In this embodiment, the projector 15 forms the pattern F of infrared light I on the screen SCR, with an illuminance distribution close to a Gaussian distribution. This allows the imaging device 710 to identify the pattern F of infrared light I with high accuracy, thereby enabling high-precision alignment.

[0073] 5, the light-transmitting member 505 of this embodiment is shifted in the optical axis direction to the opposite side of the first liquid crystal panel 400G with respect to the infrared light imaging plane 602. As a result, the first liquid crystal panel 400G is not disposed between the light-transmitting member 505 and the imaging plane 602. According to this embodiment, the distance between the light-transmitting member 505 and the infrared light imaging plane 602 can be designed without worrying about interference with the first liquid crystal panel 400G, and an image of infrared light I with a more preferable illuminance distribution can be formed on the screen SCR.

[0074] Although not shown in FIG. 5, the projection optical system 600 forms image planes for the red light R and the blue light B on the optical paths of the red light R and the blue light B, respectively. The image plane for the red light R overlaps the liquid crystal panel main body 400a of the second liquid crystal panel 400R. Similarly, the image plane for the blue light B overlaps the liquid crystal panel main body 400a of the third liquid crystal panel 400B. This allows the projection image P formed by the first liquid crystal panel 400G, the second liquid crystal panel 400R, and the third liquid crystal panel 400B to be clearly projected onto the screen SCR through the projection optical system 600.

[0075] (Moving mechanism) The movement mechanism 720 is connected to the control unit 730. The movement mechanism 720 receives an electrical signal from the control unit 730 and moves the projection optical system 600. In this way, the control unit 730 changes the position of the projected image on the screen SCR.

[0076] (Control unit) The control unit 730 is configured, for example, by a computer or integrated circuit that has built-in programs for processing the drive devices that drive the image capture device 710, the movement mechanism 720, the invisible light source device 150, and the liquid crystal panels 400R, 400G, and 400B. The control unit 730 is, for example, a processor. The control unit 730 is connected to each of the image capture device 710, the movement mechanism 720, and the liquid crystal panels 400R, 400G, and 400B via wired or wireless connections (not shown).

[0077] The image on the screen SCR may change over time due to the effects of heat generation in the projection optical system 600, the cross dichroic prism 500, and the liquid crystal panels 400R, 400G, and 400B. The control unit 730 estimates the positional deviation of the visible light image on the screen SCR based on the imaging result of the infrared light I pattern F on the screen SCR. Furthermore, the control unit 730 performs control to correct the positional deviation of the infrared light and visible light images on the screen SCR based on this estimation result.

[0078] In this embodiment, the control unit 730 can control the movement mechanism 720 based on the image captured by the imaging device 710. The control unit 730 operates the movement mechanism 720 based on the estimation result of the position of the visible light projection image P, and moves the projection optical system 600 in a direction that corrects the positional deviation of the visible light image.

[0079] Furthermore, control unit 730 may change the area of ​​the image formed in the image display area of ​​liquid crystal panels 400R, 400G, and 400B based on the image captured by imaging device 710. In this case, control unit 730 corrects the positional deviation of the visible light image by forming an image on liquid crystal panels 400R, 400G, and 400B based on the estimated position of the visible light image, and corrects the positional deviation of the image on screen SCR.

[0080] (Summary of the embodiment) The projector 15 according to the embodiment described above includes a visible light source device 20, an invisible light source device 150, a second dichroic mirror 220 as a first light combining element, a first liquid crystal panel 400G, a first incident-side polarizing plate 410G, a first exit-side polarizing plate 420G, and a projection optical system 600. The visible light source device 20 emits visible light containing green light G as a first light of a first wavelength. The invisible light source device 150 emits infrared light I as invisible light. The second dichroic mirror 220 combines the green light G and the infrared light I to generate first combined light C1. The first liquid crystal panel 400G modulates the first combined light C1. The first incident-side polarizing plate 410G transmits the green light G between the visible light source device 20 and the second dichroic mirror 220. The first exit-side polarizing plate 420G transmits the first combined light C1 on the light exit side of the first liquid crystal panel 400G. The projection optical system 600 projects the first combined light C1 exiting from the first liquid crystal panel 400G.

[0081] A projector 15 according to an embodiment includes an invisible light source device 150 that emits invisible infrared light I, in addition to a visible light source device 20 for forming a projection image. In the projector 15 according to an embodiment, the optical path of the infrared light I emitted from the invisible light source device 150 is overlapped with the optical path of green light G, which is visible light. In the projector 15 according to an embodiment, the green light G and the infrared light I, whose optical paths are overlapped with each other, pass through a common first liquid crystal panel 400G as a first combined light C1 and are projected from the projection optical system 600. Therefore, the projector 15 according to an embodiment can directly track, using invisible light (infrared light I), movement or deviation of the projected image P caused by factors on the optical path of visible light (green light G). According to the projector 15 according to an embodiment, the amount of movement of the projected image P formed by the green light G matches the amount of movement detected from the projected image Px formed by the infrared light I, and the projected image can be accurately adjusted based on the amount of movement. Furthermore, when visible light (green light G) and invisible light (infrared light I) are incident on a common first liquid crystal panel 400G as in the present embodiment, it is desirable to suppress the invisible light from being affected by modulation by the first liquid crystal panel 400G. According to the present embodiment, the first incident-side polarizing plate 410G is disposed between the visible light source device 20 and the second dichroic mirror 220, thereby avoiding the optical path of the infrared light I. Therefore, the first incident-side polarizing plate 410G can polarize the green light G that is not combined with the infrared light I. This allows the infrared light I contained in the first combined light C1 incident on the first liquid crystal panel 400G to be maintained in an unpolarized state. As a result, the infrared light I is not affected by modulation in the first liquid crystal panel 400G, and the infrared light I can be projected forward without deficiency from the projection optical system 600.

[0082] In this embodiment, a three-panel projector 15 has been described, which includes liquid crystal panels 400R, 400G, and 400B that modulate red light R, green light G, and blue light B, respectively. However, the above-described configuration may also be employed in a single-panel projector that projects monochromatic light onto a screen SCR. In a single-panel projector, white light WL is used as the first light. Therefore, in this case, the first wavelength of the first light is the wavelength of visible light (360 nm or more and 830 nm or less).

[0083] The projector 15 of one embodiment includes a color separation optical system 200, a second liquid crystal panel 400R, a third liquid crystal panel 400B, a second incident-side polarizing plate 410R, a second exit-side polarizing plate 420R, a third incident-side polarizing plate 410B, a third exit-side polarizing plate 420B, and a cross dichroic prism 500 as a second light combining element. The color separation optical system 200 separates visible light emitted from the visible light source device 20 into green light G as a first light, red light R as a second light, and blue light B as a third light. The second liquid crystal panel 400R modulates the red light R. The third liquid crystal panel 400B modulates the blue light B. The second incident-side polarizing plate 410R transmits the red light R on the light incident side of the second liquid crystal panel 400R. The second exit-side polarizing plate 420R transmits red light R on the light-exiting side of the second liquid crystal panel 400R. The third entrance-side polarizing plate 410B transmits blue light B on the light-incident side of the third liquid crystal panel 400B. The third exit-side polarizing plate 420B transmits blue light B on the light-exiting side of the third liquid crystal panel 400B. The cross dichroic prism 500 combines the first combined light C1 emitted from the first liquid crystal panel 400G, the red light R emitted from the second liquid crystal panel 400R, and the blue light B emitted from the third liquid crystal panel 400B to generate second combined light C2. The projection optical system 600 projects the second combined light C2 emitted from the cross dichroic prism 500. According to the projector 15 of one embodiment, a projector that emits image light of two or more colors can project light including infrared light I forward. Furthermore, in projector 15 that irradiates image light of two or more colors, deformation and movement of the projected image tend to become noticeable due to deformation of parts over time caused by internal heat generation in projection optical system 600, cross dichroic prism 500, liquid crystal panels 400R, 400G, 400B, etc. According to this embodiment, in projector 15 that irradiates image light of three or more colors, it is possible to correct the position of the image using infrared light I, and the effect of position correction can be more pronounced.

[0084] In projector 15 of one embodiment, the first light that is combined with infrared light I to form first combined light C1 is green light G. Of the three primary colors of light, green light G has the highest visibility. According to projector 15 of one embodiment, the optical path of infrared light I is arranged to overlap the optical path of green light G, and movement or positional deviation of components on the optical path of green light G can be directly tracked by infrared light I. This makes it possible to accurately correct the position of the image of green light G, which has high visibility, making it less likely that the viewer will notice a positional deviation of the image.

[0085] In the projector 15 of one embodiment, the first light combining element that combines the green light G as the first light and the infrared light I as the invisible light is a dichroic mirror (second dichroic mirror 220). There is one dichroic mirror through which the infrared light I is transmitted or reflected between the invisible light source device 150 and the first liquid crystal panel 400G. It is generally known that the amount of light transmitted through or reflected from a dichroic mirror is reduced or polarized each time the light is transmitted through or reflected from the dichroic mirror, depending on the transmittance or reflectance of the dichroic mirror. If the infrared light I is polarized, the infrared light I may be affected by modulation on the first liquid crystal panel 400G, resulting in a partial reduction in the amount of light in the projected image Px. According to one embodiment of the projector 15, the optical elements that pass from the invisible light source device 150 to the first liquid crystal panel 400G can be minimized, and the reduction in the amount of infrared light I projected from the projection optical system 600 can be suppressed.

[0086] In the projector 15 of one embodiment, the invisible light source device 150 has a light-emitting diode light source 150a that emits infrared light I as invisible light. The light-emitting diode light source 150a can emit unpolarized light. According to the projector 15 of one embodiment, the unpolarized infrared light I from the invisible light source device 150 can be made incident on the first liquid crystal panel 400G. This makes it possible to suppress the influence of modulation by the first liquid crystal panel 400G on the infrared light I, which makes it easier to improve the recognition accuracy of the infrared light I projected onto the screen SCR.

[0087] In the projector 15 of one embodiment, the second dichroic mirror 220 serving as the first light combining element has a first surface 220a onto which the invisible infrared light I is incident and a second surface 220b onto which the visible green light G is incident. The second dichroic mirror 220 is provided with a film that cancels out the polarized light on the first surface 220a and the second surface 220b. According to the projector 15 of one embodiment, when the infrared light I passes through the second dichroic mirror 220, the polarized light on the first surface 220a side and the second surface 220b side cancel out. That is, the second dichroic mirror 220 of one embodiment easily maintains the non-polarized state of the transmitted infrared light I. This makes it possible to suppress the influence of modulation by the first liquid crystal panel 400G on the infrared light I, thereby improving the recognition accuracy of the infrared light I projected onto the screen SCR.

[0088] In the projector 15 of one embodiment, the invisible light source device 150 emits infrared light I with a wavelength of 930 nm or more and 950 nm or less. According to the projector 15 of one embodiment, by using light with a wavelength of 930 nm or more and 950 nm or less, which has low energy in sunlight, as the infrared light I, it is possible to prevent a decrease in the contrast of the pattern F of the infrared light I due to the influence of sunlight when the infrared light I is projected onto the screen SCR. As a result, it is possible to prevent a decrease in the accuracy of position detection using the pattern F of the infrared light I.

[0089] In the projector 15 of one embodiment, the invisible light source device 150 emits infrared light I with a wavelength of 840 nm or more and 860 nm or less. A typical light source can emit light with higher efficiency as the light is closer to visible light. According to the projector 15 of one embodiment, by using light with a wavelength of 840 nm or more and 860 nm or less as the infrared light I, the energy efficiency of the invisible light source device 150 can be improved and low power consumption of the projector 15 can be achieved. Furthermore, because light sources that emit infrared light I with a wavelength of 840 nm or more and 860 nm or less are widely used as light sources of invisible light, parts can be procured inexpensively and stably, and the manufacturing cost of the projector 15 can be reduced.

[0090] The projector 15 of one embodiment includes a light-transmitting member 505 disposed between the second dichroic mirror 220 and the first exit-side polarizing plate 420G. The light-transmitting member 505 has a shielding portion 511 and a plurality of transmission portions 512. The shielding portion 511 shields the infrared light I as invisible light contained in the first combined light C1 and transmits the green light G as the first light. The transmission portions 512 transmit both the infrared light I as invisible light contained in the first combined light C1 and the green light G as the first light. The transmission portions 512 are arranged in a predetermined pattern F. The infrared light I as invisible light projected by the projection optical system 600 includes the predetermined pattern F. According to the projector 15 of one embodiment, the invisible light (infrared light I) of the predetermined pattern F is projected onto the screen SCR. Therefore, by detecting position information and the like of the predetermined pattern F using the imaging device 710, the amount of movement of the projected image P composed of visible light can be detected with high accuracy.

[0091] In the projector 15 of one embodiment, the light-transmitting member 505 has a base material 505a that transmits light, and a shielding film 505c that is formed on one surface of the base material 505a and that blocks invisible light and transmits green light G as the first light. An area on one surface of the base material 505a where the shielding film 505c is not formed forms a predetermined pattern F. According to the projector 15 of one embodiment, the shielding film 505c that absorbs infrared light I is sufficiently small relative to the entire light-transmitting member 505, making it easy to suppress a rise in temperature of the light-transmitting member 505. This makes it difficult for deterioration of the pattern F due to thermal distortion of the light-transmitting member 505 or the like to occur, making it easy to maintain high accuracy in position detection.

[0092] In the projector 15 of one embodiment, the invisible light source device 150 includes a light source 150a that emits infrared light I as invisible light, and a condenser lens 153 that transmits the invisible infrared light I emitted from the light source 150a and forms a uniform irradiation pattern. According to the projector 15 of one embodiment, the infrared light I is made uniform in amount by passing through the condenser lens 153. According to this embodiment, the invisible light source device 150 can emit infrared light I with high uniformity. This makes it possible to suppress variations in the amount of light in a plane caused by the light source 150a within the pattern F of the infrared light I formed by passing through the light-transmitting member 505. This makes it possible to improve the accuracy of position detection using the pattern F of the infrared light I. Furthermore, the use of the condenser lens 153 makes it possible to emit highly uniform infrared light I with a simple structure, thereby realizing a smaller and less expensive projector 15.

[0093] In the projector 15 of one embodiment, an image plane 601 of the projection optical system 600 using green light G as the first light overlaps the first liquid crystal panel 400G. An image plane 602 of the projection optical system 600 using infrared light I as invisible light is offset from the light-transmissive member 505 in the axial direction of the optical path of the first combined light C1. According to the projector 15 of one embodiment, the image of the binary pattern F of the infrared light I formed by transmission through the light-transmissive member 505 is out of focus on the screen SCR and has an illuminance distribution close to a Gaussian distribution. This allows the imaging device 710 to identify the pattern F of the infrared light I with high accuracy, thereby enabling high-precision alignment of the projected image P.

[0094] In the projector 15 of one embodiment, an image formation surface 602 of the projection optical system 600 using infrared light I as invisible light is shifted toward the side where the first liquid crystal panel 400G is disposed with respect to the light-transmitting member 505. In other words, the light-transmitting member 505 is shifted toward the opposite side of the first liquid crystal panel 400G with respect to the infrared light image formation surface 602. According to the projector 15 of one embodiment, the first liquid crystal panel 400G is not disposed between the light-transmitting member 505 and the infrared light image formation surface 602. Therefore, it is possible to design the distance between the light-transmitting member 505 and the image formation surface 602 regardless of the positional relationship with the first liquid crystal panel 400G, and it is possible to form an image of the infrared light I with a more preferable illuminance distribution on the screen SCR.

[0095] In one embodiment of the projector 15, the first incident-side polarizing plate 410G is an inorganic polarizing plate. When visible light (green light G) and invisible light (infrared light I) are incident on a common first liquid crystal panel 400G, it is possible to arrange an organic polarizing plate in the optical path of the first combined light C1 to prevent the invisible light from being affected by modulation by the first liquid crystal panel 400G. Some organic polarizing plates change their polarization state depending on the wavelength. Therefore, by using an organic polarizing plate, it is possible to polarize only the visible light contained in the first combined light C1 and maintain the unpolarized state of the invisible light. However, organic polarizing plates absorb a portion of the light that passes through them and generate heat, which can lead to carbonization if temperature control is not performed carefully. According to this embodiment, the first incident-side polarizing plate 410G is not arranged in the optical path of the infrared light I, so an inorganic polarizing plate with excellent heat resistance can be used as the first incident-side polarizing plate 410G. This eliminates the need for careful temperature control for the first incident-side polarizing plate 410G, thereby reducing the cost of the projector 15. In this embodiment, inorganic polarizers can also be used for polarizers other than the first incident-side polarizer 410G (the first incident-side polarizer 420G, the second incident-side polarizer 410R, the second incident-side polarizer 420R, the third incident-side polarizer 410B, and the third incident-side polarizer 420B).

[0096] A projection system 16 of one embodiment includes the above-described projector 15 and an imaging device 710 that captures a projection image Px of infrared light I projected from the projector 15. The projector 15 includes a movement mechanism 720 that moves the projection optical system 600 to change the position of the projection image Px, and a control unit 730 that controls the movement mechanism 720 based on the image captured by the imaging device 710. According to the projection system 16 of one embodiment, the projection optical system 600 can be moved to an optimal position with high precision using the control unit 730.

[0097] Projection system 16 of one embodiment includes the above-described projector 15 and an imaging device 710 that captures a projection image Px of infrared light I projected from projector 15. Projector 15 also includes a control unit 730 that changes the area of ​​an image formed in the image display area of ​​first liquid crystal panel 400G based on the image captured by imaging device 710. According to projection system 16 of this embodiment, the control unit 730 can be used to change the area of ​​the image on first liquid crystal panel 400G, thereby moving the projected image to an optimal position.

[0098] Although the present embodiment has been described with reference to a transmissive projector, the above configuration may also be applied to a reflective projector. Here, "transmissive" refers to a type in which the liquid crystal panel transmits light. "reflective" refers to a type in which the liquid crystal panel reflects light.

[0099] <Modification> Modified examples of the holding member will be described below. In the following description of each modified example, the same components as those in the embodiment already described will be assigned the same reference numerals and description thereof will be omitted.

[0100] (Variation 1) FIG. 6 is a plan view schematic diagram of a light-transmitting member 506 of a modified example. As in the above-described embodiment, the light-transmitting member 506 is disposed on the optical path of the first combined light C1, between the first incident-side polarizing plate 410G and the first exit-side polarizing plate 420G. As in the above-described embodiment, the light-transmitting member 506 has a shielding portion 511 and a plurality of transmitting portions 512. The shielding portion 511 blocks infrared light I by reflecting it and transmits visible light (particularly green light G in this modified example). On the other hand, the transmitting portions 512 transmit both infrared light I and visible light. The transmitting portions 512 are arranged in a predetermined pattern F (a dot-shaped pattern).

[0101] The light-transmitting member 506 of this modified example has a shielding plate 506a. The shielding plate 506a blocks infrared light I by reflecting or absorbing it. The shielding plate 506a also transmits visible light such as green light G. The shielding plate 506a is manufactured by forming a shielding film that blocks infrared light I and transmits visible light such as green light G on the surface of a base material made of quartz glass. The shielding plate 506a has a plurality of through-holes 506h. The through-holes 506h form a predetermined pattern F that constitutes the transmission portion 512.

[0102] According to this modification, the light-transmitting member 506 can be easily manufactured by providing the through-holes 506h in the shielding plate 506a formed on a base material. Therefore, the manufacturing cost of the projector 15 can be reduced.

[0103] In the light-transmitting member 506 of this modification, if the thickness of the shielding plate 506a is large, there is a risk that visible light will be reflected at the inner edge of the through-hole 506h. Therefore, it is preferable that the thickness of the shielding plate 506a is sufficiently thin. More specifically, it is preferable that the thickness of the shielding plate 506a is 1 mm or less.

[0104] (Variation 2) 7 is a schematic diagram showing the configuration of a projector 1015 of Modification 2. The projector 1015 of this modification differs from the above-described embodiment in the configuration for forming a predetermined pattern F in infrared light I and the configuration of the invisible light source device 160.

[0105] Compared to the above-described embodiment, the projector 1015 of this modified example does not have the light-transmitting member 505, and forms the pattern F by a diffractive optical element 507. That is, the projector 1015 of this modified example includes the diffractive optical element 507 and the collimator lens 310 instead of the light-transmitting member 505.

[0106] In the projector 1015 of this modified example, the diffractive optical element 507 and the collimating lens 310 are disposed between the invisible light source device 160 and the second dichroic mirror 220 in the optical path of the infrared light I. The diffractive optical element 507 diffracts the infrared light I passing through it to form a predetermined pattern F. The predetermined pattern F is determined by the surface pattern of the diffractive optical element 507. The collimating lens 310 collimates the infrared light I emitted from the diffractive optical element 507.

[0107] The infrared light I emitted from the diffractive optical element 507 is collimated by the collimator lens 310, and then passes through the second dichroic mirror 220, the field lens 300G, the first incident-side polarizing plate 410G, the first liquid crystal panel 400G, the first exit-side polarizing plate 420G, and the cross dichroic prism 500, before entering the projection optical system 600. An image of a predetermined pattern F of the infrared light I formed by the diffractive optical element 507 is formed near the first liquid crystal panel 400G, between the first incident-side polarizing plate 410G and the first exit-side polarizing plate 420G. The infrared light I projected by the projection optical system 600 includes the predetermined pattern F.

[0108] According to the diffractive optical element 507 of this modified example, it is possible to form a dot-shaped pattern F using a relatively simple surface pattern. Furthermore, since the diffractive optical element 507 forms an image of a predetermined pattern F in the air, there is no need to place a light-transmitting member in the optical path of visible light, and reduction in the amount of visible light can be suppressed, compared to the above-described embodiment.

[0109] In order to form the predetermined pattern F in invisible light by the diffractive optical element 507, it is preferable to use coherent light (for example, laser light) as the light to be incident on the diffractive optical element 507. By making coherent light incident on the diffractive optical element 507, the diffractive optical element 507 can form the pattern F in a desired shape without diffusing the light.

[0110] The diffractive optical element 507 of this modified example does not easily transmit visible light. According to this modified example, the diffractive optical element 507 is disposed between the invisible light source device 160 and the second dichroic mirror 220, so that the diffractive optical element 507 does not suppress the transmission of visible light.

[0111] The invisible light source device 160 of this modified example includes a laser light source 160a and a depolarization plate 170 that depolarizes the infrared light I emitted from the laser light source 160a.

[0112] The laser light source 160a is more adaptable to higher output than a light-emitting diode light source. According to this modification, the contrast ratio of the projection image Px of the infrared light I projected onto the screen SCR can be increased compared to the above-described embodiment, thereby improving the distinguishability of the imaging device 710 and increasing the accuracy of position correction. Furthermore, the laser light source 160a is more energy efficient than a light-emitting diode light source. According to this modification, the power consumption of the projector 1015 can be reduced.

[0113] The depolarizer 170 is disposed in the optical path of the infrared light I and transmits the infrared light I. The depolarizer 170 depolarizes the infrared light I that passes through. The infrared light I emitted from the laser light source 160a is incident on the depolarizer 170. The infrared light I emitted from the laser light source 160a is polarized and is, for example, linearly polarized. Because the invisible light source device 160 of this modified example includes the depolarizer 170, the emitted infrared light I can be unpolarized even when using the laser light source 160a as the light source. This makes it possible to suppress the infrared light I from being affected by modulation by the first liquid crystal panel 400G, which facilitates improving the recognition accuracy of the infrared light I projected onto the screen SCR.

[0114] 8 is a cross-sectional schematic diagram of a depolarizer 170 of this modified example. The depolarizer 170 has a first substrate 171, a first organic film 175, a liquid crystal layer 177, a second organic film 176, and a second substrate 172. The first substrate 171, the first organic film 175, the liquid crystal layer 177, the second organic film 176, and the second substrate 172 are stacked in this order along the thickness direction of the depolarizer 170.

[0115] Each of the first substrate 171 and the second substrate 172 is a light-transmitting base material made of quartz glass. The first organic film 175 is laminated on the first substrate 171. The second organic film 176 is laminated on the second substrate 172. Each of the first organic film 175 and the second organic film 176 is a polyimide film that has not been subjected to a rubbing treatment. Therefore, each of the first organic film 175 and the second organic film 176 does not have an alignment regulating force that regulates the alignment direction of the liquid crystal molecules. In other words, the first organic film 175 and the second organic film 176 do not have an alignment regulating force that aligns the liquid crystal molecules in one direction and aligns the orientation of the liquid crystal molecules.

[0116] The liquid crystal layer 177 is disposed between the first organic film 175 and the second organic film 176. As described above, the first organic film 175 and the second organic film 176 sandwiching the liquid crystal layer 177 do not have any alignment regulating force. Therefore, the alignment direction of the plurality of liquid crystal molecules 177a constituting the liquid crystal layer 177 is random. For example, as described above, each of the plurality of liquid crystal molecules 177a is randomly aligned in a plane perpendicular to the first substrate 171 or the second substrate 172. That is, the liquid crystal layer 177 includes liquid crystal molecules that are arranged with their long axis directions randomly oriented relative to the first organic film 175 and the second organic film 176.

[0117] In the depolarizer 170 of this modification, the liquid crystal molecules in the liquid crystal layer 177 are arranged with their long axes oriented randomly. When light enters this depolarizer 170, a random phase difference is imparted to the light passing through the liquid crystal layer 177. As a result, the light emerging from the depolarizer 170 can be made unpolarized.

[0118] As described above, the depolarizer 170 of this modified example is a liquid crystal type. The liquid crystal type depolarizer 170 has a very high degree of depolarization. This makes it easy to prevent the infrared light I from being affected by modulation by the first liquid crystal panel 400G, and makes it easy to improve the recognition accuracy of the projection image Px of the infrared light I projected onto the screen SCR.

[0119] In this modification, the depolarization plate 170 may be omitted by using two laser light sources (a first laser light source 160a and a second laser light source 160b) that emit S-polarized light and P-polarized light. FIG. 9 is a schematic diagram of the first laser light source 160a and the second laser light source 160b that can be employed in this modification, viewed from the optical axis direction. As shown in FIG. 9, the invisible light source device 160 may have, for example, two first laser light sources 160a and two second laser light sources 160b. The two first laser light sources 160a are arranged along a direction D1 that is perpendicular to the optical axis of the invisible light source device 160. Each of the first laser light sources 160a emits infrared S-polarized light IS. The two second laser light sources 160b are arranged along a direction D2 that is perpendicular to the optical axis and the D1 direction. Each of the second laser light sources 160b emits infrared P-polarized light IP. 9, the vibration directions of the S-polarized infrared light IS and the P-polarized infrared light IP are indicated by arrows. The two first laser light sources 160a and the two second laser light sources 160b are relatively arranged according to the light-emitting region A of the invisible light source device 160.

[0120] 10 is a diagram showing the polarization state of infrared light I emitted from laser light sources 160a and 160b using a Poincaré sphere. As shown in Fig. 10, the plot on the Poincaré sphere of infrared light I emitted from invisible light source device 160 is symmetrical with respect to the center.

[0121] According to this modification, the first laser light source 160a is arranged along direction D1, which is a first direction perpendicular to the optical axis of the invisible light source device 160, and emits infrared S-polarized light IS, which is a first light having a first polarization direction. The second laser light source 160b is arranged along direction D2, which is perpendicular to the optical axis, and emits infrared P-polarized light IP, which is a first light having a second polarization direction. With this configuration, the invisible light source device 160 can increase the amount of emitted infrared light I and irradiate infrared light I containing infrared S-polarized light IS and infrared P-polarized light IP, thereby making it possible to omit the depolarizer 170.

[0122] (Variation 3) 11 is a schematic diagram showing the configuration of a projector 2015 of Modification 3. The projector 2015 of this modification is different from the above-described embodiment mainly in that the first light that shares the optical path with the infrared light I is red light R.

[0123] A projector 2015 of this modified example has a third dichroic mirror (first light combining element) 1250 instead of the third reflecting mirror 250 in the above-described embodiment. The third dichroic mirror 1250 combines red light R as the first light and infrared light I as invisible light. That is, the third dichroic mirror 1250 transmits and reflects the infrared light I, thereby combining the light and the infrared light into a first combined light C3.

[0124] In this modification, the second liquid crystal panel 400R performs the same function as the first liquid crystal panel 400G in the above-described embodiment. That is, the second liquid crystal panel 400R modulates the first combined light C3. In this modification, the second incident-side polarizing plate 410R transmits the red light R between the invisible light source device 150 and the third dichroic mirror 1250. The second incident-side polarizing plate 410R transmits the first combined light C3 on the light-exiting side of the second liquid crystal panel 400R. Furthermore, a light-transmitting member 505 is provided in the optical path of the first combined light C3, between the second incident-side polarizing plate 410R and the second exit-side polarizing plate 420R.

[0125] According to this modification, the second incident-side polarizing plate 410R is disposed between the visible light source device 20 and the third dichroic mirror 1250. Therefore, the second incident-side polarizing plate 410R can polarize the red light R that has not been combined with the infrared light I. This makes it possible to maintain the unpolarized state of the infrared light I contained in the first combined light C1 that enters the second liquid crystal panel 400R. As a result, the infrared light I is not affected by modulation in the second liquid crystal panel 400R, and the infrared light I can be projected forward without deficiency from the projection optical system 600.

[0126] In the projector 2015 of this modified example, the invisible light is infrared light I, and the first light that shares the optical path with the infrared light is red light R. Of the three primary colors of light used to form a projected image, the red light R has a wavelength that is closest to that of the infrared light I. According to the projector 2015 of this modified example, the infrared light I and the red light R that make up the first combined light C3 have similar wavelengths, which makes it easier to improve the reflective performance of the reflective surface of the cross dichroic prism 500 that reflects the first combined light C3. As a result, it becomes easier to increase the amount of infrared light I emitted from the cross dichroic prism 500, which makes it easier to improve the recognition accuracy of the projected image Px of the infrared light I projected onto the screen SCR.

[0127] Furthermore, according to this modification, the light-transmitting member 505 is not disposed in the optical path of the green light G. This makes it possible to prevent a reduction in the amount of green light G, which has high visibility. This makes it easier to ensure the brightness of the projection image P of visible light projected from the projector 2015.

[0128] (Variation 4) 12 is a schematic diagram showing the configuration of a projector 3015 of Modification 4. The projector 3015 of this modification is different from the above-described embodiment mainly in that the first light that shares the optical path with the infrared light I is blue light B.

[0129] A projector 3015 of this modified example has a fourth dichroic mirror (first light combining element) 1240 instead of the third reflecting mirror 250 in the above-described embodiment. The fourth dichroic mirror 1240 combines blue light B as the first light with infrared light I as invisible light. That is, the fourth dichroic mirror 1240 transmits and reflects the infrared light I, thereby combining the light and the infrared light into first combined light C4.

[0130] In this modification, the third liquid crystal panel 400B performs the same function as the first liquid crystal panel 400G in the above-described embodiment. That is, the third liquid crystal panel 400B modulates the first combined light C4. In this modification, the third incident-side polarizing plate 410B transmits the blue light B between the invisible light source device 150 and the fourth dichroic mirror 1240. The third incident-side polarizing plate 410B transmits the first combined light C4 on the light-exiting side of the third liquid crystal panel 400B. Furthermore, a translucent member 505 is provided in the optical path of the first combined light C4, between the third incident-side polarizing plate 410B and the third exit-side polarizing plate 420B.

[0131] According to this modification, the third incident-side polarizing plate 410B is disposed between the visible light source device 20 and the fourth dichroic mirror 1240. Therefore, the third incident-side polarizing plate 410B can polarize the blue light B that has not been combined with the infrared light I. This makes it possible to maintain the unpolarized state of the infrared light I contained in the first combined light C1 that enters the third liquid crystal panel 400B. As a result, the infrared light I is not affected by modulation in the third liquid crystal panel 400B, and the infrared light I can be projected forward without deficiency from the projection optical system 600.

[0132] In this modification, the light-transmitting member 505 through which the first combined light C4 passes has the same configuration as in the above-described embodiment. That is, as shown in FIG. 3, the light-transmitting member 505 has a shielding film 505c that transmits visible light and blocks infrared light I by reflecting it. An edge portion 505d with a thinner film thickness may be formed at the outer edge of the shielding film 505c. The function of the shielding film 505c to transmit visible light at the edge portion 505d may be reduced, and the shielding film 505c may reflect part of the visible light with a wavelength close to that of the infrared light I. In this case, the amount of visible light passing through the light-transmitting member 505 decreases along the outer edge of the pattern F of the infrared light I.

[0133] In the projector 3015 of this modified example, the invisible light is infrared light I, and the first light that shares the optical path with the infrared light is blue light B. Of the three primary color lights used to form a projected image, blue light B has the wavelength farthest from infrared light I. Therefore, blue light B is less likely to be reflected by the edge portion 505d of the shielding film 505c, and a partial decrease in the amount of blue light B when passing through the light-transmitting member 505 can be suppressed. Furthermore, among the three primary colors, blue light B has a relatively low visibility. Therefore, even if a partial decrease in the amount of blue light B occurs in the image due to the influence of the edge portion 505d, it is unlikely to be noticed by the viewer.

[0134] Furthermore, according to this modification, it is possible to prevent a reduction in the amount of green light G, which has high visibility, without disposing the light-transmitting member 505 in the optical path of the green light G. This makes it possible to ensure the brightness of the projection image P of visible light projected from the projector 3015.

[0135] (Variation 5) 13 and 14 are schematic diagrams showing a modified projection system 1016 using the above-described projector 15. Fig. 13 shows a projected image P in the initial state or after image correction, and Fig. 14 shows a projected image P before image correction.

[0136] As shown in Fig. 13, the projection system 1016 of this modified example has multiple (two in this modified example) projectors 15 and one imaging device 710. The projection system 1016 of this modified example arranges projected images P projected from the multiple projectors 15 onto one screen SCR in the left-right direction to form one extended image E that is expanded in the left-right direction. The projected images P projected from the respective projectors 15 constitute various parts of the extended image E. Therefore, the respective projectors 15 cause their respective control units 730 to function in cooperation with each other to generate projected images P that are linked to each other.

[0137] The projected images P of the multiple projectors 15 form overlapping portions S on the screen SCR. The multiple projected images P overlap each other at the overlapping portions S. By providing the overlapping portions S, the projection system 1016 can form an extended image E on the screen SCR without any gaps between the projected images P. However, when the projection system 1016 is used continuously, the position of each projected image P changes due to changes in the ambient temperature around the projector 15 and the internal temperature due to internal heat generation. Generally, the amount of change in the position of the projected image P is required to be less than 1.5 pixels. Therefore, as shown in FIG. 14, the overlapping portions S may be deformed, disrupting the natural connection between the multiple projected images P.

[0138] In the projection system 1016 of this modified example, the control unit 730 of each projector 15 is connected to an imaging device 710. A projection image Px of infrared light I is superimposed on a projection image P of visible light projected from each projector 15. The imaging device 710 captures the projection image Px of infrared light I by fitting the entire extended image E within its angle of view. In other words, the imaging device 710 simultaneously captures the projection images Px of infrared light I projected from the multiple projectors 15.

[0139] In each projector 15, the control unit 730 corrects the position of the projection image P based on the projection image Px of infrared light I captured by the imaging device 710. In this modification, the multiple control units 730 cooperate with each other to correct the position of the image. As a result, the control unit 730 of each projector 15 adjusts the shape of the overlapping portion S between the projection images P projected from each projector 15.

[0140] The control unit 730 operates the movement mechanism 720 in each projector 15 to move the projection optical system 600 of each projector 15 and correct the position of the projected image P, thereby adjusting the shape and size of the overlapping portion S. The control unit 730 may also adjust the shape of the overlapping portion S by changing the area of ​​the image formed in the image display area of ​​the liquid crystal panels 400R, 400G, 400B of each projector 15 and correcting the position of the projected image P.

[0141] According to the projection system 1016 of this modified example, the control unit 730 can be used to move the projection optical system 600 to an optimal position with high precision. This makes it possible to reduce the number of pixels in the overlapping portion S in the direction in which the projection images P are arranged (left and right direction) to less than 1.5 pixels, allowing the viewer to perceive a natural extended image E. Furthermore, even if the positions of the multiple projection images P change over time due to heat generation or the like, the changed projection images P can be corrected, and deformation of the overlapping portion S can be suppressed.

[0142] The projection system 1016 may treat vertically arranged projected images P as one extended image E. The projection system 1016 may also include three or more projectors 15, in which case multiple projected images P arranged vertically and horizontally may be treated as one extended image E. The projection system 1016 may also include two or more imaging devices 710.

[0143] Although the preferred embodiments and modifications of the present invention have been described in detail above, the present invention is not limited to these specific embodiments and modifications, and various modifications and changes are possible within the scope of the gist of the present invention as set forth in the claims. Furthermore, the components of multiple embodiments can be combined as appropriate.

[0144] Summary of this disclosure A summary of this disclosure is provided below.

[0145] (Appendix 1) a visible light source device that emits visible light including a first light having a first wavelength; an invisible light source device that emits invisible light; a first light combining element that combines the first light and invisible light to form a first combined light; a first liquid crystal panel that modulates the first combined light; a first incident-side polarizing plate that transmits the first light between the visible light source device and the first light combining element; a first exit-side polarizing plate that transmits the first combined light on the light exit side of the first liquid crystal panel; a projection optical system that projects the first combined light emitted from the first liquid crystal panel; Equipped with projector.

[0146] According to this configuration, the projector includes an invisible light source device that emits invisible infrared light, separate from a visible light source device for forming a projection image. The optical path of the infrared light emitted from the invisible light source device overlaps with the optical path of the visible light. The overlapped visible light and invisible light then pass through a common first liquid crystal panel as a first combined light and are projected from the projection optical system. Therefore, this projector can directly track movement or deviation of the projected image due to factors along the optical path of the visible light using the invisible light. As a result, the amount of movement of the projected image composed of visible light matches the amount of movement detected from the projected image composed of invisible light, allowing accurate adjustment of the projected image based on the amount of movement. Furthermore, according to the above configuration, the first incident-side polarizing plate is disposed between the light source device and the second dichroic mirror, avoiding the optical path of the visible light. As a result, the first incident-side polarizing plate polarizes the first light that is not combined with the invisible light. As a result, the invisible light incident on the first liquid crystal panel can be maintained in an unpolarized state. The invisible light is not affected by modulation in the first liquid crystal panel, and the invisible light can be projected forward without any deficiency from the projection optical system.

[0147] (Appendix 2) a color separation optical system that separates the visible light emitted from the visible light source device into the first light, a second light having a second wavelength different from the first wavelength, and a third light having a third wavelength different from both the first wavelength and the second wavelength; a second liquid crystal panel that modulates the second light; a third liquid crystal panel that modulates the third light; a second incident-side polarizing plate that transmits the second light on the light incident side of the second liquid crystal panel; a second exit-side polarizing plate that transmits the second light on the light exit side of the second liquid crystal panel; a third incident-side polarizing plate that transmits the third light on the light incident side of the third liquid crystal panel; a third exit-side polarizing plate that transmits the third light on the light exit side of the third liquid crystal panel; a second light combining element that combines the first combined light emitted from the first liquid crystal panel, the second light emitted from the second liquid crystal panel, and the third light emitted from the third liquid crystal panel to form second combined light; the projection optical system projects the second combined light emitted from the second light combining element; 1. The projector according to claim 1.

[0148] This configuration makes it possible for a projector that emits image light of two or more colors, such as a three-panel projector, to project light including invisible light forward. Furthermore, in a projector that emits image light of two or more colors, viewers tend to perceive image misalignment due to deformation of components over time caused by internal heat generation. The above configuration allows a projector that emits image light of two or more colors to correct the position of the image using invisible light, making it possible to achieve a more pronounced effect of the position correction.

[0149] (Appendix 3) the first light is green light; 2. The projector according to claim 1,

[0150] According to this configuration, the first light that is combined with the invisible light to form the first combined light is green light. Of the three primary colors of light, green light has the highest visibility. According to this configuration, the optical path of the invisible light is arranged to overlap the optical path of the green light, and the movement or positional shift of components on the optical path of the green light can be directly tracked using the invisible light. This makes it possible to accurately correct the position of an image of green light, which has high visibility, and provides a projector that makes it difficult for viewers to perceive image positional shifts.

[0151] (Appendix 4) the first light is red light; The invisible light is infrared light. 2. The projector according to claim 1,

[0152] With this configuration, the visible light and invisible light constituting the first combined light have similar wavelengths, which makes it easier to improve the reflectivity (or transmittance) of the reflective surface (or transmissive surface) that reflects (or transmits) the first combined light in the cross dichroic mirror. As a result, it is easier to increase the amount of invisible light, which makes it easier to improve the recognition accuracy of the invisible light image projected onto the screen.

[0153] (Appendix 5) the first light is blue light; The invisible light is infrared light. 2. The projector according to claim 1,

[0154] With this configuration, visible light that passes through the translucent member has a wavelength far from invisible light, so visible light is easily transmitted through the shielding portion of the translucent member. Therefore, areas where the amount of light is reduced on the surface irradiated with visible light are unlikely to occur. Furthermore, among the three primary colors, blue light has a relatively low visibility. Therefore, even if areas where the amount of light is reduced on the surface irradiated with visible light occur, it is unlikely to be noticed by the viewer.

[0155] (Appendix 6) the first light combining element is a dichroic mirror, the number of dichroic mirrors through which the invisible light is transmitted or reflected between the invisible light source device and the first liquid crystal panel is one; 6. The projector according to any one of appendixes 1 to 5.

[0156] It is generally known that the amount of light that passes through or is reflected by a dichroic mirror is reduced each time the light passes through or is reflected by the dichroic mirror, depending on the transmittance or reflectance of the dichroic mirror. With the above-described configuration, the number of optical elements that pass from the invisible light source device to the first liquid crystal panel can be minimized, and reduction in the amount of invisible light projected from the projection optical system can be suppressed.

[0157] (Appendix 7) the invisible light source device has a light emitting diode light source that emits the invisible light, 7. The projector according to any one of appendixes 1 to 6.

[0158] Generally, a light-emitting diode light source can emit unpolarized light. According to the above configuration, unpolarized invisible light can be incident on the first liquid crystal panel from the invisible light source device. This can prevent the invisible light from being affected by modulation by the first liquid crystal panel, making it easier to improve the recognition accuracy of the invisible light projected onto the screen.

[0159] (Appendix 8) The invisible light source device has a laser light source that emits the invisible light. 7. The projector according to any one of appendixes 1 to 6.

[0160] Generally, laser light sources are more adaptable to higher output power than light-emitting diode light sources. Therefore, the above-described configuration can increase the contrast ratio of the invisible light projected onto the screen by the projector, improving the identifiability of the image capture device and increasing the accuracy of position correction. Furthermore, laser light sources are more energy efficient than light-emitting diode light sources, which can reduce the power consumption of the projector.

[0161] (Appendix 9) the invisible light source device has a depolarization plate that transmits the invisible light emitted from the laser light source and depolarizes the invisible light, 10. The projector according to claim 8.

[0162] With this configuration, the invisible light source device has a depolarizer, so even when a laser light source is used as the light source, the emitted invisible light can be made unpolarized. This makes it possible to prevent the invisible light from being affected by modulation by the first liquid crystal panel, and makes it easier to improve the recognition accuracy of the invisible light projected onto the screen.

[0163] (Appendix 10) The depolarizer is a first substrate; a second substrate disposed opposite the first substrate; a first organic film laminated on the first substrate and having no alignment control force for controlling the alignment direction of liquid crystal molecules; a second organic film laminated on the second substrate and having no alignment control force for controlling the alignment direction of liquid crystal molecules; a liquid crystal layer disposed between the first organic film and the second organic film, the liquid crystal layer including liquid crystal molecules arranged with their major axes oriented randomly relative to the first organic film and the second organic film; 10. The projector according to claim 9.

[0164] According to this configuration, a liquid crystal type depolarizer with a high degree of depolarization can be used, and it is easy to suppress polarization of invisible light emitted from the invisible light source device.

[0165] (Appendix 11) the first light combining element is a dichroic mirror that transmits the invisible light and reflects the first light, the dichroic mirror has a first surface onto which the invisible light is incident and a second surface onto which the first light is incident, The dichroic mirror is provided with a film that cancels out polarized light on the first surface and the second surface. 11. The projector according to any one of appendixes 1 to 10.

[0166] With this configuration, the invisible light remains unpolarized even when it passes through the dichroic mirror serving as the first light combining element, which reduces the influence of modulation by the first liquid crystal panel on the invisible light, making it easier to improve the recognition accuracy of the invisible light projected onto the screen.

[0167] (Appendix 12) The invisible light source device irradiates infrared light having a wavelength of 930 nm or more and 950 nm or less. 12. The projector according to any one of appendices 1 to 11.

[0168] According to this configuration, by using infrared light with a wavelength of 930 nm or more and 950 nm or less, which has low energy compared to sunlight, as the invisible light, it is possible to prevent the contrast of the invisible light pattern from decreasing due to the influence of sunlight when the invisible light is irradiated onto the screen, and as a result, it is possible to prevent a decrease in the accuracy of position detection using the invisible light pattern.

[0169] (Appendix 13) The invisible light source device irradiates infrared light having a wavelength of 840 nm or more and 860 nm or less. 12. The projector according to any one of appendices 1 to 11.

[0170] According to this configuration, by using infrared light with a wavelength of 840 nm or more and 860 nm or less as invisible light, it is possible to improve the energy efficiency of the invisible light source device and realize low power consumption of the projector. Furthermore, because light sources that irradiate infrared light with a wavelength of 840 nm or more and 860 nm or less are widely used as invisible light sources, parts can be procured cheaply and stably, and the manufacturing cost of the projector can be reduced.

[0171] (Appendix 14) a light-transmitting member disposed between the first light combining element and the first exit-side polarizing plate; The light-transmitting member is a shielding portion that shields the invisible light included in the first combined light and transmits the first light; a transmission portion that transmits both the invisible light and the first light included in the first combined light, The transmission portions are arranged in a predetermined pattern, the invisible light projected by the projection optical system includes the predetermined pattern; 14. The projector according to any one of appendices 1 to 13.

[0172] According to this configuration, a predetermined pattern of invisible light is projected onto a projection surface such as a screen, and by detecting the position information of the predetermined pattern, the amount of movement of the projected image composed of actual visible light can be detected with high accuracy.

[0173] (Appendix 15) the light-transmitting member has a shielding plate that blocks the invisible light and transmits the first light, The shielding plate is provided with through holes of the predetermined pattern. 15. The projector of claim 14.

[0174] According to this configuration, the light-transmitting member can be easily manufactured by providing through holes in the shielding plate formed on the base material, which makes it possible to reduce the manufacturing costs of the projector.

[0175] (Appendix 16) The invisible light source device is a light source that emits the invisible light; a homogenizing optical element that transmits the invisible light emitted from the light source and forms a uniform irradiation pattern, 16. The projector according to claim 14 or 15.

[0176] According to this configuration, the amount of invisible light is made uniform by passing through the uniformizing optical element. This allows the invisible light source device to emit highly uniform invisible light. This makes it possible to suppress variations in the amount of light within a surface caused by the invisible light source within the invisible light pattern formed by passing through the light-transmitting member. This increases the accuracy of position detection using the invisible light pattern. Furthermore, the use of the uniformizing optical element enables highly uniform infrared light to be emitted with a simple structure, thereby realizing a smaller and less costly projector.

[0177] (Appendix 17) an image plane of the projection optical system formed by the first light overlaps with the first liquid crystal panel; an imaging surface of the projection optical system using the invisible light is shifted from the light-transmitting member in the axial direction of the optical path of the first combined light; 17. The projector according to any one of appendixes 14 to 16.

[0178] With this configuration, the image of the binary pattern of invisible light formed by transmission through the light-transmitting member is out of focus on the screen and has an illuminance distribution close to a Gaussian distribution, which enables the imaging device to identify the invisible light pattern with high accuracy and enables highly accurate alignment of the projected image.

[0179] (Appendix 18) an image forming surface of the projection optical system using the invisible light is shifted toward the side where the first liquid crystal panel is disposed with respect to the light-transmitting member; 18. The projector of claim 17.

[0180] With this configuration, the light-transmitting member is offset from the image forming surface to the opposite side of the first liquid crystal panel. The first liquid crystal panel is not disposed between the light-transmitting member and the image forming surface. This allows the distance between the light-transmitting member and the image forming surface to be determined independently of the positional relationship with the first liquid crystal panel, allowing an invisible light image with a more desirable illuminance distribution to be formed on the screen.

[0181] (Appendix 19) a diffractive optical element disposed between the invisible light source device and the first light combining element in a light path of the invisible light, the diffractive optical element diffracting the invisible light to form a predetermined pattern; the invisible light projected by the projection optical system includes the predetermined pattern; A projector according to any one of appendices 1 to 6 and 8 to 10.

[0182] With this configuration, a diffractive optical element with a relatively simple surface pattern can form a dot-patterned invisible light projection image, thereby reducing the manufacturing costs of the projector. Furthermore, because the diffractive optical element forms an image of a predetermined pattern in the air, there is no need to place a translucent member in the optical path of visible light, and reduction in the amount of visible light can be suppressed.

[0183] (Appendix 20) the first incident-side polarizing plate is an inorganic polarizing plate; 20. The projector according to any one of appendices 1 to 19.

[0184] In a projector with this configuration, the first incident-side polarizing plate is not disposed in the optical path of invisible light. This eliminates the need to use an organic polarizing plate that does not polarize invisible light as the first incident-side polarizing plate, and instead allows for the use of an inorganic polarizing plate with excellent heat resistance. This eliminates the need for precise temperature control of the first incident-side polarizing plate, allowing for lower projector costs.

[0185] (Appendix 21) A projector according to any one of appendices 1 to 20; an imaging device that captures a projection image of invisible light projected from the projector, The projector includes: a moving mechanism that moves the projection optical system to change the position of the projected image; a control unit that controls the moving mechanism based on an image captured by the imaging device, Projection system.

[0186] According to this configuration, the projection optical system can be moved to an optimum position with high precision using the control unit.

[0187] (Appendix 22) A projector according to any one of appendices 1 to 20; an imaging device that captures a projection image of invisible light projected from the projector, the projector includes a control unit that changes an area of ​​an image formed in an image display area of ​​the first liquid crystal panel based on an image captured by the imaging device, Projection system.

[0188] According to this configuration, the control unit can be used to change the area of ​​the image on the first liquid crystal panel, and move the projected image to an optimal position.

[0189] (Appendix 23) a plurality of the projectors; the imaging device simultaneously captures the invisible light of the projection images projected from the plurality of projectors, the control unit of each of the projectors adjusts the amount of overlap between the projection images projected from each of the projectors; 23. The projection system according to claim 21 or 22.

[0190] With this configuration, the control unit can move the projection optical system to the optimal position with high precision, adjust the amount of overlap in the direction in which the multiple projected images are aligned, and allow the viewer to perceive a natural extended image. Furthermore, even if the positions of the multiple projected images change over time due to heat generation or other reasons, the changed projected images can be corrected to prevent deformation of the overlapping portions. [Explanation of symbols]

[0191] 15, 1015, 2015, 3015...Projector, 16, 1016...Projection system, 20...Visible light source device, 150, 160...Invisible light source device, 150a...Light source, 150a...Light-emitting diode light source, 153...Condenser lens (homogenizing optical element), 160a, 160b...Laser light source, 170...Depolarization plate, 171...First substrate, 172...Second substrate, 17 5...first organic film, 176...second organic film, 177...liquid crystal layer, 177a...liquid crystal molecules, 200...color separation optical system, 210...dichroic mirror, 220...second dichroic mirror (first light combining element), 220a...first surface, 220b...second surface, 400G...first liquid crystal panel, 400R...liquid crystal panel, 400R...second liquid crystal panel, 410G...first incident side polarizing plate, 410R...second Incident side polarizing plate, 410R...incident side polarizing plate, 420G...first exit side polarizing plate, 420R...exit side polarizing plate, 420R...second exit side polarizing plate, 500...cross dichroic prism (second light combining element), 505, 506...light-transmitting member, 505a...base material, 505c...shielding film, 506a...shielding plate, 506h...through hole, 507...diffractive optical element, 511...shielding portion, 512...transmitting portion, 6 00...Projection optical system, 601, 602...Image forming surface, 710...Image capture device, 720...Moving mechanism, 730...Control unit, 1240...Fourth dichroic mirror (first light combining element), 1250...Third dichroic mirror (first light combining element), B...Blue light, C1, C3, C4...First combined light, C2...Second combined light, F...Pattern, G...Green light, I...Infrared light, P, Px...Projected image, R...Red light

Claims

1. a visible light source device that emits visible light including a first light having a first wavelength; an invisible light source device that emits invisible light; a first light combining element that combines the first light and the invisible light to form a first combined light; a first liquid crystal panel that modulates the first combined light; a first incident-side polarizing plate that transmits the first light between the visible light source device and the first light combining element; a first exit-side polarizing plate that transmits the first combined light on the light exit side of the first liquid crystal panel; a projection optical system that projects the first combined light emitted from the first liquid crystal panel; Equipped with projector.

2. a color separation optical system that separates the visible light emitted from the visible light source device into the first light, a second light having a second wavelength different from the first wavelength, and a third light having a third wavelength different from both the first wavelength and the second wavelength; a second liquid crystal panel that modulates the second light; a third liquid crystal panel that modulates the third light; a second incident-side polarizing plate that transmits the second light on the light incident side of the second liquid crystal panel; a second exit-side polarizing plate that transmits the second light on the light exit side of the second liquid crystal panel; a third incident-side polarizing plate that transmits the third light on the light incident side of the third liquid crystal panel; a third exit-side polarizing plate that transmits the third light on the light exit side of the third liquid crystal panel; a second light combining element that combines the first combined light emitted from the first liquid crystal panel, the second light emitted from the second liquid crystal panel, and the third light emitted from the third liquid crystal panel to form second combined light, the projection optical system projects the second combined light emitted from the second light combining element; The projector according to claim 1 .

3. the first light is green light; The projector according to claim 2 .

4. the first light is red light, The invisible light is infrared light. The projector according to claim 2 .

5. the first light is blue light, The invisible light is infrared light. The projector according to claim 2 .

6. the first light combining element is a dichroic mirror, the number of dichroic mirrors through which the invisible light is transmitted or reflected between the invisible light source device and the first liquid crystal panel is one; The projector according to claim 1 .

7. the invisible light source device has a light emitting diode light source that emits the invisible light, The projector according to claim 1 .

8. The invisible light source device has a laser light source that emits the invisible light. The projector according to claim 1 .

9. the invisible light source device has a depolarization plate that transmits the invisible light emitted from the laser light source and depolarizes the invisible light, The projector according to claim 8 .

10. The depolarizer is a first substrate; a second substrate disposed opposite the first substrate; a first organic film laminated on the first substrate and having no alignment control force for controlling the alignment direction of liquid crystal molecules; a second organic film laminated on the second substrate and having no alignment control force for controlling the alignment direction of liquid crystal molecules; a liquid crystal layer disposed between the first organic film and the second organic film, the liquid crystal layer including liquid crystal molecules arranged with their major axes oriented randomly relative to the first organic film and the second organic film; The projector according to claim 9.

11. the first light combining element is a dichroic mirror that transmits the invisible light and reflects the first light, the dichroic mirror has a first surface onto which the invisible light is incident and a second surface onto which the first light is incident, The dichroic mirror is provided with a film that cancels out polarized light on the first surface and the second surface. The projector according to claim 1 .

12. The invisible light source device irradiates infrared light having a wavelength of 930 nm or more and 950 nm or less. The projector according to claim 1 .

13. The invisible light source device irradiates infrared light having a wavelength of 840 nm or more and 860 nm or less. The projector according to claim 1 .

14. a light-transmitting member disposed between the first light combining element and the first exit-side polarizing plate, The light-transmitting member is a shielding portion that blocks the invisible light included in the first combined light and transmits the first light; a transmission portion that transmits both the invisible light and the first light included in the first combined light, The transmission portions are arranged in a predetermined pattern, the invisible light projected by the projection optical system includes the predetermined pattern; The projector according to claim 1 .

15. the light-transmitting member has a shielding plate that blocks the invisible light and transmits the first light, The shielding plate is provided with through holes of the predetermined pattern. The projector according to claim 14.

16. The invisible light source device is a light source that emits the invisible light; a homogenizing optical element that transmits the invisible light emitted from the light source and forms a uniform irradiation pattern, The projector according to claim 14.

17. an image forming surface of the projection optical system formed by the first light overlaps with the first liquid crystal panel; an image forming surface of the projection optical system using the invisible light is shifted from the light-transmitting member in the axial direction of the optical path of the first combined light; The projector according to claim 14.

18. an image forming surface of the projection optical system using the invisible light is shifted toward the side where the first liquid crystal panel is disposed with respect to the light-transmitting member; The projector according to claim 17.

19. a diffractive optical element disposed between the invisible light source device and the first light combining element in a light path of the invisible light, the diffractive optical element diffracting the invisible light to form a predetermined pattern; the invisible light projected by the projection optical system includes the predetermined pattern; The projector according to claim 1 .

20. the first incident-side polarizing plate is an inorganic polarizing plate; The projector according to claim 1 .

21. The projector according to claim 1 ; an imaging device that captures a projection image of invisible light projected from the projector, The projector includes: a moving mechanism that moves the projection optical system to change the position of the projected image; a control unit that controls the moving mechanism based on an image captured by the imaging device, Projection system.

22. The projector according to claim 1 ; an imaging device that captures a projection image of invisible light projected from the projector, the projector includes a control unit that changes an area of ​​an image formed in an image display area of ​​the first liquid crystal panel based on an image captured by the imaging device, Projection system.

23. a plurality of the projectors; the imaging device simultaneously captures the invisible light of the projection images projected from the plurality of projectors, the control unit of each of the projectors adjusts the amount of overlap between the projection images projected from each of the projectors; 23. The projection system according to claim 21 or 22.

Images