Projector and projection system

Abstract

To provide a projector and a projection system that can project a bright and clear image.SOLUTION: A projector of the present invention comprises: a light source device that emits light; a light modulation device that modulates the light emitted from the light source device; a first polarization element that transmits, of the light emitted from the light modulation element, first polarized light in a first polarization direction; a projection optical device that projects the light emitted from the first polarization element; and a pattern generation unit that is arranged between the first polarization element and the projection optical device. The pattern generation unit provides a phase difference to a part of the first polarized light incident from the first polarization element to generate a pattern formed of second polarized light in a second polarization direction different from the first polarization direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In an image display device such as a projector, in order to control a visible image to be displayed, a visible image and an invisible image such as an infrared image may be superimposed on a screen, and the visible image may be adjusted 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] JP 2008-176195 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the device disclosed in the above-mentioned Patent Document 1, in addition to the light modulation devices for each color light of red light, green light, and blue light, which are visible light, a light modulation device for infrared light, which is invisible light, is arranged. Therefore, it is not possible to directly track the movement or deviation of the projected image caused by some factor on the optical path of each color light of visible light. As a result, there is a problem that the amount of movement of the projected image composed of the actual visible light does not match the detected amount of movement, making it difficult to accurately adjust the projected image based on the amount of movement. [Means for solving the problem]

[0005] In order to solve the above problems, a projector of one embodiment of the present invention comprises a light source device that emits light, a light modulation element that modulates the light emitted from the light source device, a first polarizing element that transmits a first polarized light having a first polarization direction among the light emitted from the light modulation element, a projection optical device that projects the light emitted from the first polarizing element, and a pattern generation unit arranged between the first polarizing element and the projection optical device, wherein the pattern generation unit imparts a phase difference to a portion of the first polarized light incident from the first polarizing element to generate a pattern consisting of a second polarized light having a second polarization direction different from the first polarization direction.

[0006] One embodiment of the projection system of the present invention is a projection system equipped with a projector that projects a projection image and an imaging device that captures the projection image, in which the projector has a light source device that emits light, a light modulation element that modulates the light emitted from the light source device, a first polarizing element that transmits a first polarized light of a first polarization direction among the light emitted from the light modulation element, a pattern generation unit that is arranged on the light emission side of the first polarizing element and imparts a phase difference to a portion of the first polarized light incident from the first polarizing element to convert it into a pattern consisting of a second polarized light of a second polarization direction different from the first polarization direction, and a control device that changes the area where an image is formed in the image forming area of ​​the light modulation element based on the pattern included in the projection image captured by the imaging device. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view showing a schematic configuration of a projector according to a first embodiment. [Diagram 2] FIG. 2 is a plan view of the optical element. [Diagram 3] FIG. 1 is a diagram illustrating a schematic configuration of an imaging device. [Figure 4] FIG. 13 is a diagram showing an inversion pattern. [Diagram 5] FIG. 11 is a plan view showing the configuration of a main part of a movement mechanism of a projector according to a second embodiment. [Figure 6A] 5A to 5C are explanatory diagrams of the operation of the moving mechanism. [Figure 6B] 11A to 11C are explanatory diagrams of the operation of a moving mechanism. [Figure 7A] 13 is a diagram showing a rotation device which is a main part of a projector according to a third embodiment. FIG. [Figure 7B] 10A and 10B are diagrams for explaining an example of operation of a rotation device. [Figure 8] FIG. 13 is a diagram showing the configuration of a main part of a projector according to a fourth embodiment. [Figure 9] FIG. 13 is a diagram relating to a modified example of the fourth embodiment. [Figure 10] FIG. 13 is a diagram showing a configuration of a main part of a projector according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (First embodiment) Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. The drawings used in the following description may show characteristic portions in an enlarged scale in order to make the characteristics easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality.

[0009] An example of a projector according to this embodiment will be described. FIG. 1 is a plan view showing a schematic configuration of a projector according to the present embodiment. As shown in Fig. 1, the projector 1 of this embodiment is a projection type image display device that displays a color image on a screen SCR, which is a projection surface, and is a liquid crystal projector that uses a liquid crystal panel as a light modulation device. That is, the projector 1 projects a projection image onto the screen SCR. The projector 1 of this embodiment includes a light source device 10, a light collecting optical system 15, a light modulation device 20, a projection optical device 30, an optical element 40, an imaging device 50, and a control device CONT.

[0010] In the following description, an XYZ Cartesian coordinate system is used as necessary. The X axis is an axis along the up-down direction of the projector 1. The Z axis is an axis along the image projection direction of the projector 1 and along the front-rear direction of the projector 1. The Y axis is an axis along the left-right direction of the projector 1 and perpendicular to the X axis and Z axis. When describing the arrangement and shape of each member in the projector 1, two directions parallel to the X axis direction corresponding to the height when the projector 1 is viewed from the front from the image projection side are sometimes referred to as the up-down direction X, two directions parallel to the Y axis direction corresponding to the lateral direction when the projector 1 is viewed from the front from the image projection side are sometimes referred to as the left-right direction Y, and two directions parallel to the Z axis direction corresponding to the depth when the projector 1 is viewed from the front from the image projection side are sometimes referred to as the front-rear direction Z. These notations are definitions for describing the arrangement relationship of each component of the projector 1, and do not limit the installation posture or direction of the projector 1.

[0011] In the projector 1 of this embodiment, an axis that runs along the principal ray of the white light L emitted from the light source device 10, passes through the center of the light modulation device 20, and is parallel to the Z axis is defined as an illumination optical axis AX.

[0012] The light source device 10 is composed of, for example, a light emitting diode (LED). The light source device 10 emits unpolarized white light L having a predetermined divergence angle. Here, the unpolarized white light L is light that does not have a specific polarization state such as linear polarization or circular polarization. The unpolarized white light L is, for example, randomly polarized light. Since the light source device 10 is composed of LEDs, the projector 1 can be made smaller and lighter.

[0013] The light-collecting optical system 15 includes a first lens 15a and a second lens 15b. The first lens 15a and the second lens 15b are, for example, convex lenses. The light-collecting optical system 15 collimates the white light L emitted from the light source device 10 at a predetermined divergence angle and emits the parallel light toward the light modulation device 20.

[0014] The light modulation device 20 includes an incident-side polarizing plate 21, a light modulation element 22, and an exit-side polarizing plate .

[0015] The incident-side polarizing plate 21 is provided between the light-collecting optical system 15 and the light modulation element 22, that is, on the light incident side of the light modulation element 22. White light L emitted from the light source device 10 is incident on the incident-side polarizing plate 21. The incident-side polarizing plate 21 transmits light L1, which is linearly polarized in a predetermined direction, out of the white light L, and emits the light L1 toward the light modulation element 22. The light L1 is, for example, P-polarized light.

[0016] The light modulation element 22 is composed of one transmissive liquid crystal panel capable of color display. That is, the light modulation element 22 has a color filter, and emits modulated light L2 obtained by modulating light L1 incident from the incident-side polarizing plate 21 based on image information. The modulated light L2 is, for example, light including both P-polarized light and S-polarized light. The driving method of the liquid crystal panel is not particularly limited, and may be a twisted nematic (TN) method, a vertical alignment (VA) method, an in-plane switching (IPS) method, or the like.

[0017] The exit side polarizing plate 23 is provided between the light modulation element 22 and the condensing optical system 15, that is, on the light exit side of the light modulation element 22. The polarization axis of the exit side polarizing plate 23 is arranged in a direction perpendicular to the polarization axis of the entrance side polarizing plate 21, for example, in a virtual plane perpendicular to the illumination optical axis AX. The exit side polarizing plate 23 generates image light G, which is the source of a color image, from the modulated light L2 exited from the light modulation element 22. That is, in order to form a color image, the exit side polarizing plate 23 transmits, for example, P-polarized light and blocks S-polarized light from the modulated light L2, thereby exiting the P-polarized image light G. The exit side polarizing plate 23 in this embodiment corresponds to the "first polarizing element." Moreover, the image light G is linearly polarized light having a predetermined polarization direction, and corresponds to the "first polarized light in the first polarization direction" in this embodiment.

[0018] In this way, the light modulation device 20 emits the image light G as first polarized light in a first polarization direction, for example, P-polarized light, toward the optical element 40. The optical element 40 is disposed between the emission-side polarizing plate 23 of the light modulation device 20 and the projection optical device 30, i.e., on the light emission side of the emission-side polarizing plate 23. The external shape of the optical element 40 has a size equal to or larger than the external shape of the emission-side polarizing plate 23.

[0019] Fig. 2 is a plan view of the optical element 40. Fig. 2 is a view of the optical element 40 viewed from the -Z direction to the +Z direction. As shown in Fig. 2, the optical element 40 has a light-transmitting substrate 40a, a plurality of polarizing sections 41 that are provided on the substrate 40a and form a pattern generating section 41a, and a transmitting section 42 that is formed in an area of ​​the substrate 40a where the polarizing sections 41 are not arranged and transmits the image light G. The polarizing sections 41 are arranged in a dot pattern on the rectangular substrate 40a. By using such an optical element 40, it is possible to easily generate image light G1 that includes a predetermined pattern PA, as described later. The image light G1 is, for example, light that includes both P-polarized light and S-polarized light, as will be described in detail later.

[0020] The polarizing unit 41 is, for example, composed of a 1 / 2 wavelength plate that imparts a phase difference of 1 / 2 wavelength to the incident light and rotates the polarization direction of linearly polarized light by 90 degrees. The polarizing unit 41 of this embodiment imparts the above-mentioned phase difference to colored light of a predetermined wavelength band among the white light L emitted from the light source device 10. Specifically, the polarizing unit 41 imparts a phase difference of 1 / 2 wavelength to blue light having a blue wavelength band among the white light L. In other words, the polarizing unit 41 has optical characteristics with wavelength dependency that impart a phase difference to the first polarized light of blue light having a blue wavelength band among the white light L, and does not impart a phase difference to the first polarized light of red light having a red wavelength band and green light having a green wavelength band. In this embodiment, the blue light having the blue wavelength band corresponds to the "first colored light having the first wavelength band."

[0021] 1, the pattern generating unit 41a consisting of a plurality of polarizing units 41 applies a phase difference to the P-polarized blue image light GB, which is a part of the image light G incident from the exit-side polarizing plate 23, and converts the light into second polarized light having a second polarization direction different from the first polarization direction, thereby generating a pattern PA consisting of, for example, S-polarized light. The predetermined pattern PA is a pattern consisting of a plurality of polarizing units 41 arranged on the optical element 40, and in this embodiment, is dot-shaped. Therefore, the image light G1 transmitted through the optical element 40 includes the dot-shaped pattern PA having a blue color.

[0022] On the other hand, the image light G emitted from the exit-side polarizing plate 23 contains, in addition to the blue image light GB, red image light GR in the red wavelength band and green image light GG in the green wavelength band. The polarization directions of the red image light GR and the green image light GG do not change before and after passing through the optical element 40. In other words, the red image light GR and the green image light GG are each the first polarized light. Furthermore, the component of the blue image light GB that has passed through the transmitting sections 42 of the optical element 40 is not given a phase difference by the polarizing section 41, and therefore becomes the first polarized light like the red image light GR and the green image light GG. That is, the red image light GR, the green image light GG, and the blue image light GB that has passed through the transmitting sections 42 become the first polarized light G1p, which is, for example, P polarized light, and the blue image light GB that has passed through the multiple polarizing sections 41 becomes the second polarized light G1s, which is, for example, S polarized light and constitutes the pattern PA.

[0023] The image light G1 transmitted through the optical element 40 in this manner includes the second polarized light G1s consisting of the blue dot pattern PA, and the first polarized light G1p consisting of a part of the blue image light GB, the red image light GR, and the green image light GG.

[0024] The projection optical device 30 is composed of a plurality of projection lenses. The projection optical device 30 projects image light G1 including a pattern PA toward the screen SCR. That is, the projection image projected onto the screen SCR includes the pattern PA. A part of the light constituting the image light G1 projected onto the screen SCR is incident on the imaging device 50. That is, the imaging device 50 captures the projection image projected by the projection optical device 30. In the projector 1 of this embodiment, the imaging device 50 is mounted in a housing that forms the exterior of the projector 1.

[0025] In general, it is difficult for the human eye to distinguish between different polarization directions. Therefore, when viewing the image light G1 projected on the screen SCR, the viewer's eyes have difficulty recognizing the pattern PA contained in the image light G1. In other words, the projector 1 of this embodiment embeds the pattern PA with a different polarization direction in the image light G1, so that it is possible to suppress the occurrence of discomfort caused by recognizing the pattern PA when viewing the image light G1. In the case of this embodiment, light in the blue wavelength band, in which the visibility of the human eye is relatively low, is used as the pattern PA, so that the pattern PA included in the image light G1 can be made difficult to perceive.

[0026] The control device CONT is configured, for example, by a computer or an integrated circuit having built-in programs for processing the driving devices that drive the imaging device 50, the light source device 10, and the light modulation device 20. That is, the control device CONT is, for example, a processor. The control device CONT is connected to each of the imaging device 50, the light source device 10, and the light modulation device 20 by wired or wireless means (not shown).

[0027] FIG. 3 is a diagram showing a schematic configuration of the imaging device 50. As shown in FIG. 3, the imaging device 50 has a lens 51, an imaging element 52, a polarizing element 53, and a housing 54. The lens 51 guides light constituting the image light G1 to the imaging element 52. The imaging element 52 is, for example, an image sensor such as a CCD sensor or a CMOS sensor. That is, the imaging device 50 is, for example, a camera module. The polarizing element 53 in this embodiment corresponds to a "second polarizing element."

[0028] The polarizing element 53 is disposed on the light incident side of the imaging element 52, and has the property of transmitting the second polarized light to make it incident on the imaging element 52, while blocking the first polarized light. Specifically, the polarizing element 53 transmits the second polarized light G1s constituting the pattern PA of the image light G1, and blocks a part of the blue image light GB, the red image light GR, and the green image light GG constituting the components other than the pattern PA made of the first polarized light G1p. The housing 54 accommodates therein the lens 51, the image sensor 52, and the polarizing element 53. The housing 54 has an intake section 54a formed of an opening or a transmission window for taking in the image light G1. The polarizing element 53 may be disposed outside the housing unit 54 .

[0029] In this way, the polarizing element 53 causes a component corresponding to the pattern PA contained in the image light G1 to be incident on the imaging element 52. Therefore, the imaging device 50 can extract and image the dot-shaped pattern PA embedded in the projected image formed by the image light G1 by the imaging element 52. The imaging device 50 transmits the imaging result of the imaging element 52 to the control device CONT.

[0030] The polarizing element 53 may have a characteristic of transmitting the first polarized light to be incident on the imaging element 52 and blocking the second polarized light. In this case, the polarizing element 53 blocks the second polarized light G1s constituting the pattern PA of the image light G1, and transmits a part of the blue image light GB, the red image light GR, and the green image light GG constituting the components other than the pattern PA consisting of the first polarized light G1p. Thus, the imaging element 52 can capture an inverted image of the projection image formed by the image light G1, in which the blue image light GB of the part corresponding to the pattern PA is omitted, as a pattern. This allows the imaging device 50 to distinguish the inverted pattern consisting of the second polarized light embedded in the image light G1 as a marker indicating position information on the screen SCR.

[0031] In this case, it is preferable to place a color filter that selectively transmits the blue wavelength band in front of the image sensor 52. In this way, the red image light GR and the green image light GG are blocked by the color filter. Therefore, the image sensor 52 has a shape that is an inversion of the dot-shaped pattern PA formed by the blue image light GB that constitutes the components other than the pattern PA, and can capture the pattern PA1 formed by the first polarized light G1p shown in FIG. The color filter may be disposed outside the imaging device 50.

[0032] The control device CONT changes the area in which the image light G is formed in the image forming area 22a of the light modulation element 22, according to the imaging result of the pattern PA imaged by the imaging device 50. Here, the image forming area 22a of the light modulation element 22 corresponds to a pixel forming area provided in a liquid crystal panel constituting the light modulation element 22.

[0033] (Effects of the first embodiment) The projector 1 of the present embodiment includes a light source device 10 that emits white light L, a light modulation element 22 that modulates the white light L emitted from the light source device 10, an exit-side polarizing plate 23 that transmits image light G, which is a first polarized light in a first polarization direction, out of the modulated light L2 emitted from the light modulation element 22, a projection optical device 30 that projects the image light G1 emitted from the exit-side polarizing plate 23, and a pattern generating unit 41a disposed between the exit-side polarizing plate 23 and the projection optical device 30. The pattern generating unit 41a imparts a phase difference to blue image light GB, which is a part of the image light G incident from the exit-side polarizing plate 23, to generate a pattern PA made of second polarized light in a second polarization direction different from the first polarization direction. In addition, the projector 1 of this embodiment further includes an imaging device 50 that captures a projection image formed by the image light G1 projected by the projection optical device 30, and a control device CONT that changes the area in which the image light is formed in the image forming area 22a of the light modulation element 22 based on a pattern PA contained in the projection image captured by the imaging device 50.

[0034] According to the projector 1 of the present embodiment, the image light G1 embedded with the pattern PA functioning as a marker can be projected onto the screen SCR. The image forming area 22a of the light modulation element 22 may be burned due to deterioration over time, for example, and the light transmittance may decrease, which may affect the displayed image. In such a case, according to the projector 1 of the present embodiment, the image light G1 including the pattern PA generated using the image light G modulated by the image forming area 22a of the light modulation element 22 is projected onto the screen SCR. Therefore, if a defect occurs in the image forming area 22a of the light modulation element 22, a problem such as distortion may also occur in the pattern PA included in the image light G1.

[0035] Therefore, the projector 1 of the present embodiment can detect the state of the image forming area 22a of the light modulation device 20 based on the imaging result of the pattern PA projected on the screen SCR. Therefore, the projector 1 can project a bright and clear image onto the screen SCR by changing the area where image light is formed in the image forming area 22a of the light modulation element 22 according to the state of the image forming area 22a.

[0036] Furthermore, since the projector 1 of this embodiment embeds the pattern PA that functions as a marker in the image light G1, there is no need to install a separate light source for generating the pattern PA. Therefore, by providing a light source for pattern generation, the amount of light incident on the optical member increases, making it possible to suppress the occurrence of color unevenness caused by polarization disturbance due to heat generation, positional deviation of the image projection position, and the like. Also, it is possible to suppress the increase in size and weight caused by providing a light source for pattern generation.

[0037] In addition, since the projector 1 of this embodiment can accurately detect the position information of the image forming area 22a of the light modulation device 20 based on the imaging results of the pattern PA projected onto the screen SCR, it is also suitable for applications such as overlapping and displaying projected images from multiple projectors on the screen SCR.

[0038] In the projector 1 of the present embodiment, the case where the blue pattern PA is embedded in the image light G1 has been taken as an example, but the pattern PA embedded in the image light G1 may be red or green. In addition, in the projector 1 of the present embodiment, the case where the polarizing unit 41 of the optical element 40 imparts a phase difference of 1 / 2 wavelength to the incident light has been exemplified, but the phase difference imparted by the polarizing unit 41 is not limited to 1 / 2 wavelength. For example, depending on the type of image light G1, the pattern PA may be easily visible, and in this case, the amount of phase difference imparted may be changed from 1 / 2 wavelength to reduce the proportion of the second polarized light that constitutes the pattern PA, thereby suppressing the visibility of the pattern PA.

[0039] Second embodiment Next, the configuration of a projector according to a second embodiment will be described. The difference between this embodiment and the first embodiment is that a movement mechanism is provided. Therefore, the configuration of the movement mechanism will be mainly described below. Note that the same reference numerals are used to designate components common to the first embodiment, and descriptions thereof will be omitted.

[0040] Fig. 5 is a plan view showing the main configuration of the movement mechanism. Fig. 6A and Fig. 6B are explanatory diagrams of the operation of the movement mechanism. In Fig. 6A and Fig. 6B, the projection optical device 30 and the screen SCR are omitted for ease of viewing. 5, the projector 2 of the present embodiment includes a movement mechanism 25 that moves the optical element 40 in the left-right direction Y along the Y-axis direction that intersects with the optical axis of the emission-side polarizing plate 23. Note that the optical axis 23C of the emission-side polarizing plate 23 coincides with the illumination optical axis AX of the light source device 10, as shown in FIGS. 6A and 6B.

[0041] The moving mechanism 25 has a holding frame 26 that holds the optical element 40, a light-transmitting substrate 27 held by the holding frame 26, a driving unit 28 consisting of a motor, and a gear member 28a rotatably attached to the driving unit 28. The driving of the driving unit 28 is controlled by a control device CONT. The holding frame 26 is a frame that holds the optical element 40 and the light-transmitting substrate 27 aligned in the left-right direction Y. In the present embodiment, the optical element 40 is disposed on the +Y side of the light-transmitting substrate 27 in the left-right direction Y.

[0042] The holding frame 26 has a rack portion 26a provided along the left-right direction Y on the -X side, which is the lower side in the up-down direction X. The holding frame 26 is movable in the left-right direction Y when a gear member 28a meshing with the rack portion 26a is rotated by a drive unit 28.

[0043] Based on such a configuration, the moving mechanism 25 can switch between an arrangement state S1 in which the optical element 40 is arranged on the optical axis 23C of the emission-side polarizing plate 23 as shown in FIG. 6A and a retreated state S2 in which the optical element 40 is retreated from the optical axis 23C of the emission-side polarizing plate 23 and the light-transmitting substrate 27 is arranged on the optical axis 23C as shown in FIG. 6B by rotating the gear member 28a by the driving unit 28 to move the holding frame 26 in the left-right direction Y. Note that the moving mechanism 25 can easily switch between the arrangement state S1 and the retreated state S2 by reversing the rotation direction of the gear member 28a by the driving unit 28 shown in FIG. 5. That is, the moving mechanism 25 can easily advance and retreat the optical element 40 with respect to the optical axis 23C.

[0044] 6A, the projector 2 can place the optical element 40 on the optical path of the image light G emerging from the exit-side polarizing plate 23. This causes the projection optical device 30 to project the image light G1 including the pattern PA onto the screen SCR.

[0045] 6B, the projector 2 can place the light-transmitting substrate 27 on the optical path of the image light G emitted from the emission-side polarizing plate 23. As a result, the image light G is projected onto the screen SCR by the projection optical device 30 by transmitting through the light-transmitting substrate 27.

[0046] Therefore, according to the projector 2 of the present embodiment, it is possible to easily switch between a state in which image light G1 including the pattern PA is projected onto the screen SCR and a state in which image light G not including the pattern PA is projected. Therefore, when generation of the pattern PA is not required, a clear image not including a pattern can be visually recognized by the viewer.

[0047] Third embodiment Next, the configuration of a projector according to a third embodiment will be described. The difference between this embodiment and the first embodiment is that a rotation device that rotates the optical element is provided. Therefore, the configuration of the rotation device will be mainly described below. Note that the same reference numerals are used to designate components common to the first embodiment, and descriptions thereof will be omitted.

[0048] FIG. 7A is a diagram showing a rotation device which is a main component of the projector 3 of this embodiment. As shown in FIG. 7A, the projector 3 of this embodiment includes an optical element 140 and a rotation device 149 that rotates the optical element 140 around a rotation axis (not shown). The optical element 140 is constituted by a light-transmitting circular plate 140a, and has an arrangement region 141 in which a pattern generating portion 148 is arranged, and a non-arrangement region 142 in which no pattern generating portion 148 is arranged.

[0049] The placement region 141 includes a first region 141a in which a first pattern portion P1 constituting the pattern generating section 148 is placed, a second region 141b in which a second pattern portion P2 constituting the pattern generating section 148 is placed, and a third region 141c in which a third pattern portion P3 constituting the pattern generating section 148 is placed.

[0050] The non-application area 142 is a light-transmitting area constituted by a part of the disk 140a. Therefore, the non-application area 142 functions as an area that transmits incident light without imparting a phase difference to the light.

[0051] When the optical element 140 is viewed in a plan view, the first region 141a, the second region 141b, and the third region 141c of the arrangement region 141 and the non-arrangement region 142 are arranged in order in the rotation direction of the disk 140a. The first region 141a, the second region 141b, the third region 141c, and the non-arrangement region 142 are all rectangular, and have a size equal to or larger than the outer shape of the exit-side polarizing plate 23.

[0052] The first pattern portion P1 includes a plurality of first polarizing portions 143 arranged in a dot pattern. Each of the first polarizing portions 143 imparts a predetermined phase difference to incident light and rotates the polarization direction of linearly polarized light by a predetermined angle.

[0053] The second pattern portion P2 includes a plurality of second polarizing portions 144 arranged in a dot pattern. The second pattern portion P2 differs from the first pattern portion P1 in at least one of the pattern shape and the degree of phase difference imparted. For example, the second pattern portion P2 sets a phase difference by each second polarizing portion 144 so as to impart a phase difference larger than the phase difference imparted to the incident light by each first polarizing portion 143. As a result, the second pattern portion P2 imparts a larger degree of phase difference than the first pattern portion P1.

[0054] The third pattern portion P3 includes a plurality of third polarizing portions 145 arranged in a dot pattern. The third pattern portion P3 is different from the first pattern portion P1 and the second pattern portion P2 in at least one of the pattern shape and the degree of phase difference imparted. The third pattern portion P3 has a different layout from the first polarizing portion 143 and the second polarizing portion 144, for example, the third polarizing portions 145 are formed in a large dot shape. This allows the third pattern portion P3 to generate a different pattern shape from the first pattern portion P1 and the second pattern portion P2.

[0055] The second pattern portion P2 may have a different pattern shape in addition to the degree of phase difference imparted by arranging each second polarizing portion 144 in a layout different from that of the first polarizing portion 143. The third pattern portion P3 may have a different degree of phase difference imparted in addition to the pattern shape by setting the phase difference of each third polarizing portion 145 so as to impart a phase difference different from that of the first polarizing portion 143 and the second polarizing portion 144.

[0056] The rotation device 149 is, for example, a motor. FIG. 7B, the rotation device 149 can rotate the optical element 140 to switch between a first state SS1 in which the first pattern portion P1 of the first region 141a is located on the optical axis 23C of the emission-side polarizing plate 23, a second state SS2 in which the second pattern portion P2 of the second region 141b is located on the optical axis 23C of the emission-side polarizing plate 23, a third state SS3 in which the third pattern portion P3 of the third region 141c is located on the optical axis 23C of the emission-side polarizing plate 23, and a fourth state SS4 in which the non-arrangement region 142 is located on the optical axis 23C of the emission-side polarizing plate 23. That is, the optical element 140 of this embodiment is arranged inside the projector 3 so that the image light G emitted from the emission-side polarizing plate 23 is incident along the optical axis 23C on the region above the rotation device 149 in FIG.

[0057] 7B, the projector 3 of the present embodiment can change the polarization state of the pattern PA contained in the image light G1 or the shape of the pattern PA by switching the pattern portions P1, P2, and P3 arranged on the optical path of the image light G emitted from the emission-side polarizing plate 23. This makes it possible to generate an appropriate pattern PA according to the surface condition of the projection surface such as the screen SCR.

[0058] Furthermore, in the projector 3 of this embodiment, by arranging a non-placement area 142 on the optical path of the image light G emitted from the emission-side polarizing plate 23, the image light G that does not include the pattern PA can be projected onto the screen SCR, allowing the viewer to view a clearer image.

[0059] (Fourth embodiment) Next, a description will be given of the configuration of a projector according to the fourth embodiment. Note that the same components as those in the first embodiment are given the same reference numerals, and the description will be omitted. Fig. 8 is a diagram showing the configuration of the main parts of the projector 4 of this embodiment. In Fig. 8, in order to make the drawing easier to see, the imaging device 50, the control device CONT, and the screen SCR are omitted from the illustration. As shown in FIG. 8, the projector 4 of this embodiment includes a light source device 10, a light collection optical system 15, a light modulation device 20, a projection optical device 30, and a pattern generation section 44a.

[0060] In the projector 4 of this embodiment, the pattern generating unit 44a is disposed on the light exit surface 23a of the exit-side polarizing plate 23. The pattern generating unit 44a is constituted by a plurality of polarizing units 44 arranged in a dot pattern, for example. Each polarizing unit 44 is constituted by a retardation film that imparts a predetermined phase difference to the blue image light GB, which is a part of the image light G incident from the exit-side polarizing plate 23. For this reason, each polarizing unit 44 is directly attached to the light exit surface 23a of the exit-side polarizing plate 23.

[0061] According to the projector 4 of this embodiment, a pattern generating section 44a consisting of multiple polarizing sections 44 is arranged on the light exit surface 23a of the exit side polarizing plate 23, so that the device configuration can be simplified by omitting the substrate 40a from the configuration of the first embodiment in which the optical element 40 is arranged between the exit side polarizing plate 23 and the projection optical device 30.

[0062] A light-transmitting member may be disposed in an area where the pattern generating portion 44a is not disposed on the light exit surface 23a of the exit-side polarizing plate 23. Fig. 9 is a diagram relating to a modified example of the fourth embodiment, and shows a configuration in which a light-transmitting member is disposed.

[0063] In the configuration shown in FIG. 9, a light-transmitting member 45 that does not impart a phase difference is disposed in an area of ​​the light exit surface 23a where the pattern generating portion 44a is not disposed. That is, the light-transmitting member 45 is disposed so as to fill the gap between the pattern generating portions 44a. The thickness of the light-transmitting member 45 along the optical axis 23C of the exit-side polarizing plate 23 is equal to the thickness of the pattern generating portion 44a along the optical axis 23C. In this specification, the fact that the thickness of the light-transmitting member 45 and the thickness of the pattern generating portion 44a are equal not only means that the thicknesses are completely the same, but also means that the thicknesses are approximately equal with a difference of ±5% or less.

[0064] By disposing the light-transmitting member 45 around the pattern generating portion 44a in this manner, it is possible to make it difficult for the pattern generating portion 44a to peel off from the light exit surface 23a of the exit-side polarizing plate 23. Furthermore, by making the thicknesses of the pattern generating portion 44a and the light-transmitting member 45 approximately equal, it is possible to suppress the occurrence of a difference in the focal position of the light transmitted through the pattern generating portion 44a and the light-transmitting member 45, respectively, and to suppress the pattern included in the image light from being easily recognized.

[0065] Fifth embodiment Next, the configuration of the projector of the fifth embodiment will be described. The difference between this embodiment and the first embodiment is the optical characteristics of the polarizing unit that configures the pattern generating unit. Note that the same reference numerals are used to designate components that are common to the first embodiment, and descriptions thereof will be omitted.

[0066] Fig. 10 is a diagram showing the configuration of the main parts of a projector 5 according to the present embodiment. In Fig. 10, in order to make the drawing easier to see, the image capturing device 50 and the control device CONT are omitted from the illustration. 10, the projector 5 of this embodiment has an optical element 240. The optical element 240 of this embodiment has a light-transmitting substrate 240a and a plurality of polarizing units 241 forming a pattern generating unit 241a. The plurality of polarizing units 241 are arranged in a dot pattern on the substrate 240a.

[0067] In this embodiment, the polarizing unit 241 imparts a phase difference of 1 / 2 wavelength to colored light of a predetermined wavelength band among the white light L emitted from the light source device 10. Specifically, the polarizing unit 241 imparts a phase difference to a first polarized light of blue light having a blue wavelength band among the white light L, a first polarized light of green light having a green wavelength band among the white light L, and a first polarized light of red light having a red wavelength band among the white light L. That is, the polarizing unit 241 of this embodiment has an optical characteristic of imparting a phase difference to the first polarized light of the entire visible light band included in the white light L. In this embodiment, the green light having the green wavelength band corresponds to the "second colored light having the second wavelength band."

[0068] The pattern generating unit 241a, which is composed of a plurality of polarizing units 241, applies a phase difference to each of the red image light GR, the green image light GG, and the blue image light GB, which are part of the image light G incident from the exit-side polarizing plate 23, and converts them into second polarized light having a second polarization direction different from the first polarization direction, thereby generating a pattern PA2. The red image light GR, the green image light GG, and the blue image light GB constituting the image light G2 transmitted through the optical element 240 each include a dot-shaped pattern consisting of the second polarization of each color light. In other words, the image light G2 includes patterns PA2 having the same color but different polarization directions.

[0069] Since the pattern PA in the first embodiment is composed of only one color, blue, it is difficult to generate the pattern PA when an image other than blue is projected using the image light G1. In contrast, since the pattern PA2 generated by the projector 5 in this embodiment has the same color as the image light G2, for example, even when an image composed of the image light G2 of only one color is projected, the pattern PA2 generated in the image light G2 can be identified by the imaging device 50. Therefore, according to the projector 5 in this embodiment, the robustness of pattern identification is improved, resulting in greater reliability.

[0070] In the present embodiment, the pattern generating unit 241a applies a phase difference to each of the red image light GR, the green image light GG, and the blue image light GB, but the pattern generating unit 241a may apply a phase difference to any two of the red image light GR, the green image light GG, and the blue image light GB. According to this configuration, by embedding a two-color pattern in the image light, it is possible to improve the pattern identification ability compared to the case of using a single-color pattern.

[0071] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. In addition, one aspect of the present invention can be a configuration in which the characteristic portions of the above-described embodiments are appropriately combined. For example, the pattern embedded in the image light changes in brightness depending on the image projected on the screen, so depending on the type of image, the pattern may be difficult to identify. In response to this, a display area suitable for using a marker in the projected image may be determined in advance, thereby narrowing the area in the image light where the pattern is generated. In this way, the pattern generation area is narrowed, making it easier to judge the imaging results of the imaging device and improving the identifiability of the pattern. Alternatively, the imaging device may perform image processing such as superimposing images acquired over a certain period of time to enhance the identifiability of the marker.

[0072] In the projector of the above embodiment, the image capturing device 50 is built into the housing of the projector. That is, the projector includes the image capturing device 50, but the present invention is not limited to this.

[0073] For example, the present invention can also be applied to a projection system in which an image capturing device is separate from a projector. The projection system has the following configuration. The projection system of the present invention includes a projector 1 that projects image light and an imaging device 50 that captures the image light G1. The projector 1 includes a light source device 10, a light modulation element 22 that modulates the light emitted from the light source device 10, an exit side polarizing plate 23 that transmits a first polarized light having a first polarization direction among the light emitted from the light modulation element 22, and a pattern generating unit 41a that is arranged on the light exit side of the exit side polarizing plate 23 and applies a phase difference to a portion of the first polarized light incident from the exit side polarizing plate 23 to convert it into a pattern PA consisting of a second polarized light having a second polarization direction different from the first polarization direction, and a control device CONT that changes the area where image light is formed in the image forming area 22a of the light modulation element 22 based on the pattern PA contained in the image light G1 captured by the imaging device 50.

[0074] According to the projection system of the present invention, it is possible to detect the state of the image forming area 22a of the light modulation device 20 based on the imaging result of the pattern PA projected on the screen SCR. Therefore, the projection system can project a bright and clear image onto the screen SCR by changing the area where the image light is formed in the image forming area 22a of the light modulation element 22 according to the state of the image forming area 22a.

[0075] Furthermore, in this projection system, the projector 1 embeds the pattern PA that functions as a marker in the image light G1, so there is no need to install a separate light source for generating the pattern PA. Therefore, by providing a light source for pattern generation, the amount of light incident on the optical member increases, making it possible to suppress the occurrence of color unevenness caused by polarization disturbance due to heat generation and the occurrence of misalignment of the image projection position. Also, it is possible to suppress the increase in size and weight caused by providing a light source for pattern generation. In addition, since this projection system can accurately detect the position information of the image forming area 22a of the light modulation device 20 based on the imaging results of the pattern PA projected onto the screen SCR, it can also be applied to applications such as overlapping and displaying projected images from multiple projectors on the screen SCR.

[0076] In the projector of the above embodiment, a liquid crystal panel capable of color display is used as the light modulation element. However, a liquid crystal panel that displays a single color, that is, a liquid crystal panel that does not have a color filter, may be used as the light modulation element.

[0077] The present invention can also be applied to a single-panel sequential color display projector in which a light modulation element is driven in synchronization with different color lights emitted in sequence from a light source device.

[0078] The projector in the above embodiment is an example of irradiating white light onto the entire surface of the light modulation element, but the present invention can also be applied to a single-panel projector in which red light, green light, and blue light are incident on the light modulation element from three different directions. The present invention is also applicable to a scanning illumination type monochrome projector that uses a rotating prism to scan illumination light onto one light modulation element, and also to a scanning illumination type sequential color display projector that drives a light modulation element in synchronization with the color of the incident illumination light. The present invention is also applicable to a laser scanning type projector that scans a laser beam on a light modulation element without using a rotating prism.

[0079] The moving mechanism 25 included in the projector 2 of the second embodiment described above has the light-transmitting substrate 27, and in the retracted state S2 of the optical element 40, the light-transmitting substrate 27 is disposed on the optical axis 23C of the emission-side polarizing plate 23, but this is not limited to this. For example, the moving mechanism may not have a transparent base material, and the retracted state may simply be a state in which the optical element 40 is not present on the optical axis 23C of the emission-side polarizing plate 23.

[0080] Furthermore, the specific descriptions of the shape, number, arrangement, material, and the like of each component of the light source device and the projector are not limited to the above-described embodiment and can be modified as appropriate.

[0081] Summary of the Disclosure The following is a summary of this disclosure. (Appendix 1) A light source device that emits light; a light modulation element that modulates the light emitted from the light source device; a first polarizing element that transmits a first polarized light having a first polarization direction out of the light emitted from the light modulation element; a projection optical device that projects the light emitted from the first polarizing element; a pattern generating unit disposed between the first polarizing element and the projection optical device; Equipped with the pattern generating unit generates a pattern including a second polarized light having a second polarization direction different from the first polarization direction by imparting a phase difference to a portion of the first polarized light incident from the first polarizing element. A projector characterized by:

[0082] According to the projector having the configuration of Appendix 1, it is possible to project light in which a pattern that functions as a marker is embedded. In a projector having this configuration, a pattern is embedded in light modulated by a light modulation element, so if a malfunction occurs in the light modulation element, problems such as distortion will also occur in the pattern. Therefore, this projector can project a bright and clear image by changing the light modulation area of ​​the light modulation element according to the state of the light modulation element.

[0083] (Appendix 2) Further comprising an optical element disposed on the light exit side of the first polarizing element, The optical element has a polarizing section constituting the pattern generating section and a transmitting section that transmits the first polarized light. 3. The projector according to claim 2,

[0084] According to the configuration of Supplementary Note 2, light including a predetermined pattern can be easily generated by using an optical element.

[0085] (Appendix 3) a moving mechanism for moving the optical element along a direction intersecting the optical axis of the first polarizing element, the moving mechanism is capable of switching between an arrangement state in which the optical element is arranged on the optical axis and a retracted state in which the optical element is retracted from the optical axis. 3. The projector according to claim 2,

[0086] According to the configuration of Supplementary Note 3, the optical element can be easily advanced and retreated with respect to the optical axis by the moving mechanism. This allows the viewer to view a clear image that does not include a pattern when generation of a pattern is not required.

[0087] (Appendix 4) A rotation device that rotates the optical element is further provided, the optical element has an arrangement region in which the pattern generating portion is arranged and a non-arrangement region in which the pattern generating portion is not arranged, The rotation device is capable of switching between a state in which the arrangement region is positioned on the optical axis of the first polarizing element and a state in which the non-arrangement region is positioned on the optical axis of the first polarizing element by rotating the optical element. 3. The projector according to claim 2,

[0088] According to the configuration of Supplementary Note 4, the optical element can be easily advanced and retreated with respect to the optical axis by the rotation device. This allows the viewer to view a clear image that does not include a pattern when generation of a pattern is not required.

[0089] (Appendix 5) the arrangement region includes a first region in which a first pattern portion constituting the pattern generating unit is arranged, and a second region in which a second pattern portion constituting the pattern generating unit, the second pattern portion having at least one of a pattern shape and a degree of phase difference imparted different from that of the first pattern portion, is arranged, The rotation device is capable of switching between a first state in which the first region is disposed on the optical axis of the first polarizing element and a second state in which the second region is disposed on the optical axis of the first polarizing element by rotating the optical element. 5. The projector according to claim 4.

[0090] According to the configuration of Supplementary Note 5, the polarization state of the pattern or the shape of the pattern can be changed by switching the pattern parts arranged on the optical path of the light emitted from the exit-side polarizing plate. This makes it possible to generate an appropriate pattern according to the surface condition of the projection surface.

[0091] (Appendix 6) The pattern generating unit is disposed on the light exit surface of the first polarizing element. 6. The projector according to claim 1,

[0092] According to the configuration of Supplementary Note 6, the pattern generating section is disposed on the light exit surface of the first polarizing element, thereby simplifying the device configuration.

[0093] (Appendix 7) a light-transmitting member is disposed in a region of the light exit surface where the pattern generating unit is not disposed, a thickness of the light-transmitting member along the optical axis of the first polarizing element is equal to a thickness of the pattern generating portion along the optical axis; 7. The projector according to claim 6,

[0094] According to the configuration of Supplementary Note 7, by arranging a translucent member around the pattern generating portion, it is possible to make it difficult for the pattern generating portion to peel off from the light exit surface of the first polarizing element. In addition, by making the thickness of the pattern generating portion and the translucent member substantially equal, it is possible to suppress the occurrence of a difference in the focal position of the light transmitted through the pattern generating portion and the translucent member, respectively, and to suppress the pattern included in the image light from being easily recognized.

[0095] (Appendix 8) the light source device emits white light as the light, the pattern generating unit converts the first polarized light of a first color light having a first wavelength band among the white light into the second polarized light to generate the pattern. 8. The projector according to claim 1,

[0096] According to the configuration of Supplementary Note 8, since it is only necessary to impart a phase difference to the first wavelength band of the white light, the optical design becomes easy.

[0097] (Appendix 9) The first color light is blue light. 9. The projector according to claim 8,

[0098] According to the configuration of Supplementary Note 9, blue light, which has a relatively low visibility to the human eye, is used as a pattern, so that the pattern included in the image can be made difficult to recognize.

[0099] (Appendix 10) The pattern generating unit converts the first polarized light of the first color light and the first polarized light of a second color light having a second wavelength band of the white light different from the first wavelength band into the second polarized light. 9. The projector according to claim 8,

[0100] According to the configuration of Supplementary Note 10, by embedding a two-color pattern in the image light, it is possible to improve pattern discrimination compared to a single-color pattern.

[0101] (Appendix 11) an imaging device that captures a projection image projected by the projection optical device; and a control device that changes an area in which an image is formed in the image forming area of ​​the light modulation element based on the pattern included in the projection image captured by the imaging device. 8. The projector according to claim 1,

[0102] According to the configuration of Appendix 11, a bright and clear image can be projected by changing the area in which image light is formed in the image forming area of ​​the light modulation element depending on the state of the image forming area determined based on the imaging results of the pattern.

[0103] (Appendix 12) the imaging device includes an imaging element into which light constituting the projection image is incident, and a second polarizing element disposed on a light incident side of the imaging element; the second polarizing element transmits the second polarized light to be incident on the imaging element and blocks the first polarized light. 12. The projector according to claim 11.

[0104] According to the configuration of Supplementary Note 12, a component corresponding to the pattern made of the second polarized light included in the image light can be made incident on the imaging element, and thus the pattern made of the second polarized light can be imaged.

[0105] (Appendix 13) the imaging device includes an imaging element into which light constituting the projection image is incident, and a second polarizing element disposed on a light incident side of the imaging element; the second polarizing element transmits the first polarized light to be incident on the imaging element and blocks the second polarized light. 12. The projector according to claim 11.

[0106] According to the configuration of Supplementary Note 13, a component corresponding to a pattern made of the first polarized light, which is an inverted shape of the pattern made of the second polarized light, can be made incident on the imaging element, and thus the pattern made of the first polarized light can be imaged.

[0107] (Appendix 14) A projection system including a projector that projects a projection image and an imaging device that captures the projection image, The projector includes: A light source device that emits light; a light modulation element that modulates the light emitted from the light source device; a first polarizing element that transmits a first polarized light having a first polarization direction out of the light emitted from the light modulation element; a pattern generating unit that is disposed on the light exit side of the first polarizing element and that applies a phase difference to a portion of the first polarized light incident from the first polarizing element to convert the portion into a pattern made of second polarized light having a second polarization direction different from the first polarization direction; a control device that changes an area in which an image is formed in an image forming area of ​​the light modulation element based on the pattern included in the projection image captured by the imaging device; having A projection system comprising:

[0108] According to the projection system of the configuration of Supplementary Note 14, since a pattern is embedded in the light modulated by the light modulation element, if a malfunction occurs in the light modulation element, problems such as distortion will also occur in the pattern. Therefore, this projection system can project a bright and clear image by changing the light modulation area of ​​the light modulation element according to the state of the light modulation element. [Explanation of symbols]

[0109] Reference Signs List 1, 2, 3, 4, 5... projector, 10... light source device, 22... light modulation element, 22a... image forming area, 23... exit side polarizing plate (first polarizing element), 23a... light exit surface, 23C... optical axis, 25... movement mechanism, 30... projection optical device, 40, 140, 240... optical element, 41, 44, 241... polarizing section, 41a, 44a, 148, 241a... pattern generating section, 42... transmission section, 45... light-transmitting member, 50... imaging device, 52... imaging element child, 53...polarizing element (second polarizing element), 141...placement area, 141a...first area, 141b...second area, 142...non-placement area, 149...rotation device, CONT...control device, G, G1, G2...image light, G1p...first polarized light, G1s...second polarized light, L...white light, P1...first pattern portion, P2...second pattern portion, PA, PA1, PA2...pattern, S1...placement state, S2...retracted state, SS1...first state, SS2...second state.

Claims

1. A light source device that emits light; a light modulation element that modulates the light emitted from the light source device; a first polarizing element that transmits a first polarized light having a first polarization direction out of the light emitted from the light modulation element; a projection optical device that projects the light emitted from the first polarizing element; a pattern generating unit disposed between the first polarizing element and the projection optical device; Equipped with the pattern generating unit generates a pattern including a second polarized light having a second polarization direction different from the first polarization direction by imparting a phase difference to a part of the first polarized light incident from the first polarizing element. A projector characterized by:

2. Further comprising an optical element disposed on the light exit side of the first polarizing element, The optical element has a polarizing section constituting the pattern generating section and a transmitting section that transmits the first polarized light.

2. The projector according to claim 1,

3. a moving mechanism for moving the optical element along a direction intersecting the optical axis of the first polarizing element, the moving mechanism is capable of switching between an arrangement state in which the optical element is arranged on the optical axis and a retracted state in which the optical element is retracted from the optical axis.

3. The projector according to claim 2.

4. A rotation device that rotates the optical element is further provided, the optical element has an arrangement region in which the pattern generating portion is arranged and a non-arrangement region in which the pattern generating portion is not arranged, The rotation device is capable of switching between a state in which the arrangement region is positioned on the optical axis of the first polarizing element and a state in which the non-arrangement region is positioned on the optical axis of the first polarizing element by rotating the optical element.

3. The projector according to claim 2.

5. the arrangement region includes a first region in which a first pattern portion constituting the pattern generating unit is arranged, and a second region in which a second pattern portion constituting the pattern generating unit, the second pattern portion having at least one of a pattern shape and a degree of phase difference imparted different from that of the first pattern portion, is arranged, The rotation device is capable of switching between a first state in which the first region is disposed on the optical axis of the first polarizing element and a second state in which the second region is disposed on the optical axis of the first polarizing element by rotating the optical element.

5. The projector according to claim 4.

6. The pattern generating unit is disposed on the light exit surface of the first polarizing element.

2. The projector according to claim 1,

7. a light-transmitting member is disposed in a region of the light exit surface where the pattern generating unit is not disposed, a thickness of the light-transmitting member along the optical axis of the first polarizing element is equal to a thickness of the pattern generating portion along the optical axis; 7. The projector according to claim 6.

8. the light source device emits white light as the light, the pattern generating unit converts the first polarized light of a first color light having a first wavelength band among the white light into the second polarized light to generate the pattern. The projector according to any one of claims 1 to 7.

9. The first color light is blue light. The projector according to claim 8 .

10. The pattern generating unit converts the first polarized light of the first color light and the first polarized light of a second color light having a second wavelength band of the white light different from the first wavelength band into the second polarized light. The projector according to claim 8 .

11. an imaging device that captures a projection image projected by the projection optical device; and a control device that changes an area in which an image is formed in the image forming area of ​​the light modulation element based on the pattern included in the projection image captured by the imaging device. The projector according to any one of claims 1 to 7.

12. the imaging device includes an imaging element into which light constituting the projection image is incident, and a second polarizing element disposed on a light incident side of the imaging element; the second polarizing element transmits the second polarized light to be incident on the imaging element and blocks the first polarized light. The projector according to claim 11 .

13. the imaging device includes an imaging element into which light constituting the projection image is incident, and a second polarizing element disposed on a light incident side of the imaging element; the second polarizing element transmits the first polarized light to be incident on the imaging element and blocks the second polarized light. The projector according to claim 11 .

14. A projection system including a projector that projects a projection image and an imaging device that captures the projection image, The projector includes: A light source device that emits light; a light modulation element that modulates the light emitted from the light source device; a first polarizing element that transmits a first polarized light having a first polarization direction out of the light emitted from the light modulation element; a pattern generating unit that is disposed on the light exit side of the first polarizing element and that applies a phase difference to a portion of the first polarized light incident from the first polarizing element to convert the portion into a pattern made of second polarized light having a second polarization direction different from the first polarization direction; a control device that changes an area in which an image is formed in an image forming area of ​​the light modulation element based on the pattern included in the projection image captured by the imaging device; having A projection system comprising:

Images