# US 2019/0174105 A1 · Projection display unit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0174105 A1 - Document ID: US20190174105A1 - Status: Published application - Kind: A1 - Application number: 16/210,456 - Filed: 2018-12-05 - Published: 2019-06-06 - Earliest claimed: 2014-07-29 - Assignees: Sony Corporation - Applicants: Sony Corporation - Inventors: Kazumasa Kaneda; Toshio Mamiya - Web page: https://patentgrep.com/patent/US20190174105A1 ## CPC - H04N 9/3191: {Testing thereof (testing of displays in general G09G3/006)} - G02B 27/283: {used for beam splitting or combining} - G03B 17/54: with projector - G03B 21/00: Projectors or projection-type viewers; Accessories therefor (devices for changing pictures G03B23/00) - G03B 21/14: Details - G03B 21/2073: {Polarisers in the lamp house (peculiar to electronic spatial light modulators H04N9/3197)} - G03B 21/208: {Homogenising, shaping of the illumination light} - G06F 3/0421: {by interrupting or reflecting a light beam, e.g. optical touch-screen} - H04N 5/74: Projection arrangements for image reproduction, e.g. using eidophor - H04N 9/3164: {using multiple light sources} - H04N 9/3167: {for polarizing the light beam (polarizing optical systems per se G02B27/28)} - H04N 9/317: {Convergence or focusing systems (electronic adjustment of convergence H04N9/3185; convergence or focusing arrangements for cathode ray tubes H04N9/28; means for automatic focusing of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/53)} - H04N 9/3194: {including sensor feedback} - H04N 9/3197: {using light modulating optical valves} - G06F 3/0425: {using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected (tracking a projected light spot to determine a position on a display surface G06F3/0386)} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A projection display unit includes a projection optical system, a polarization separation device, and a detection optical system. The projection optical system includes an illuminator, a projection lens, and a light valve. The light valve modulates illumination light supplied from the illuminator on a basis of an image signal, and outputs the modulated illumination light toward the projection lens. The polarization separation device is disposed between the light valve and the projection lens. The polarization separation device separates entering light into a first polarized component and a second polarized component, and outputs the first polarized component and the second polarized component in respective directions that are different from each other. The detection optical system includes an imaging device. The imaging device is disposed in a position that is optically conjugate to a position of the light valve, and receives, via the projection lens and the polarization separation device, light based on invisible light applied along a plane in vicinity of the projection surface. The following conditional expression (1): d1<β×d2 is satisfied. ## Claims ### Claim 1 A projection display unit comprising: a projection optical system including an illuminator, a projection lens, and a light valve that modulates illumination light supplied from the illuminator on a basis of an image signal, and outputs the modulated illumination light toward the projection lens; and a detection optical system configured to include an imaging device, the imaging device being disposed in a position that is optically conjugate to a position of the light valve, and receiving, via the projection lens, light based on invisible light applied along a plane in vicinity of the projection surface. ### Claim 2 (depends on 1) The projection display unit according to claim 1, further comprising: a polarization separation device disposed between the light valve and the projection lens, the polarization separation device separating entering light into a first polarized component and a second polarized component, and outputting the first polarized component and the second polarized component in respective directions that are different from each other. ### Claim 3 (depends on 1) The projection display unit according to claim 1, wherein the following conditional expression is satisfied, d1<β×d2 (1) where d1 is a diagonal size of the light valve, d2 is a diagonal size of the imaging device, and β is an optical magnification, of the detection optical system, β being greater than 1 when the detection optical system is a reduction optical system, being smaller than 1 when the detection optical system is an enlargement optical system, and being equal to 1 when the detection optical system is an equal magnification optical system. ### Claim 4 (depends on 1) The projection display unit according to claim 1, wherein in a position substantially corresponding to a focal length of the projection lens, a planar shape corresponding to an effective region of the light valve is a first rectangular shape, and an image circle of the projection lens is not in contact with the first rectangular shape and encompasses the first rectangular shape. ### Claim 5 (depends on 4) The projection display unit according to claim 4, wherein, in the position substantially corresponding to the focal length of the projection lens or a position that is optically conjugate to the position substantially corresponding to the focal length of the projection lens, a planar shape corresponding to an effective region of the imaging device is a second rectangular shape, the second rectangular shape having a central position that is substantially same as a central position of the first rectangular shape and being greater in size than the first rectangular shape, and the image circle of the projection lens encompasses the second rectangular shape. ### Claim 6 (depends on 5) The projection display unit according to claim 5, wherein the imaging device receives part of light, out of the invisible light, that is reflected by an object, and the image circle has a radius that satisfies the following conditional expression, R1≥R0+h/α×tan θmin (2) where R1 is the radius of the image circle of the projection lens, R0 is a radius of a circle that is in contact with a pair of vertices of the effective region of the light valve, “h” is a height, from the projection surface, of the plane along which the invisible light is to be applied, α is a projection magnification, and θmin is a minimum value of an angle formed by the projection surface and the part of the reflected light entering the detection optical system. ### Claim 7 (depends on 6) The projection display unit according to claim 6, wherein the following expression (3): β×d2≥d1+2h/α×tan θmin is further satisfied. ### Claim 8 (depends on 1) The projection display unit according to claim 1, wherein the detection optical system includes a reduction optical system between the polarization separation device and the imaging device, the reduction optical system having one or more relay lens groups. ### Claim 9 (depends on 1) The projection display unit according to claim 1, wherein the detection optical system includes a visible light cut filter between the polarization separation device and the imaging device, the visible light cut filter reducing a visible light component. ### Claim 10 (depends on 1) The projection display unit according to claim 1, wherein the detection optical system includes a polarizer between the polarization separation device and the imaging device, the polarizer selectively removing one of the first polarized component and the second polarized component. ### Claim 11 (depends on 1) The projection display unit according to claim 1, further comprising a signal processor that detects a position, on the projection surface, of an object on a basis of an imaging signal obtained from the imaging device. ### Claim 12 (depends on 1) The projection display unit according to claim 1, wherein the projection lens is a short throw lens. ### Claim 13 (depends on 12) The projection display unit according to claim 12, further comprising a light source provided on a casing, the light source outputting the invisible light. ### Claim 14 (depends on 1) The projection display unit according to claim 1, wherein the invisible light is near-infrared light. ### Claim 15 (depends on 1) The projection display unit according to claim 1, wherein the polarization separation device is a polarizing beam splitter. ### Claim 16 (depends on 15) The projection display unit according to claim 15, wherein the light valve is a reflective liquid crystal display device. ### Claim 17 (depends on 16) The projection display unit according to claim 16, wherein the polarization separation device has a first surface, a second surface, a third surface, and a fourth surface that each serve as a light entering surface or a light output surface, and the polarization separation device outputs, from the second surface, the first polarized component out of light that has entered the polarization separation device from the first surface, outputs, from the third surface, the second polarized component out of the light that has entered the polarization separation device from the first surface, outputs, from the fourth surface, the second polarized component out of light that has entered the polarization separation device from the second surface, and outputs, from the third surface, the first polarized component out of light that has entered the polarization separation device from the fourth surface. ### Claim 18 (depends on 17) The projection display unit according to claim 17, wherein the projection optical system is configured to allow the illuminator to output the illumination light toward the first surface of the polarization separation device, the light valve to modulate the first polarized component, out of the illumination light, that has been outputted from the second surface of the polarization separation device, and output light resulting from the modulation toward the second surface of the polarization separation device, and the projection lens to project, toward the projection surface, light, out of the modulated light, that has been outputted from the fourth surface of the polarization separation device. ### Claim 19 (depends on 18) The projection display unit according to claim 18, wherein the detection optical system is configured to allow the reduction optical system to receive object detection light via the projection lens, the fourth surface of the polarization separation device, and the third surface of the polarization separation device, and the imaging device to receive light outputted from the reduction optical system.