# US 10,503,056 B2 · Projector and method of controlling projector that determines whether a lens has been replaced > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,503,056 B2 - Document ID: US10503056B2 - Status: Granted - Kind: B2 - Application number: 15/987,202 - Filed: 2018-05-23 - Published: 2018-11-29 - Granted: 2019-12-10 - Earliest claimed: 2017-05-29 - Assignees: Seiko Epson Corporation - Applicants: Seiko Epson Corporation - Inventors: Yusuke Kudo - Web page: https://patentgrep.com/patent/US10503056B2 ## CPC - G03B 21/142: {Adjusting of projection optics} - 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} - 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) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A projector includes a drive section adapted to move a projection lens, a projection section adapted to project image light through the projection lens, and a determination section adapted to determine whether or not the projection lens has been replaced based on a first position as a position of the projection lens at a first time point at which power supply to the projector is stopped, and a second position as a position of the projection lens at a second time point at which the power supply is started after the first time point. ## Claims ### Claim 1 A projector comprising: a projection lens having a focus lens and a zoom lens; a drive section adapted to move the projection lens; a projection section adapted to project image light through the projection lens; a determination section adapted to determine whether or not the projection lens has been replaced based on: a first relationship between a position of the focus lens at a first time point at which power supply to the projector is stopped, and a position of the focus lens at a second time point at which the power supply is started after the first time point, and a second relationship between a position of the zoom lens at the first time point and a position of the zoom lens at the second time point; a detection section adapted to detect a position of the projection lens; and a projection control section adapted to make the projection section project a message for prompting a user to make the projector measure a relationship between an actual position of the projection lens and a position of the projection lens detected by the detection section in a case in which the determination section has determined that the projection lens has been replaced. ### Claim 2 (depends on 1) The projector according to claim 1, wherein the determination section determines that the projection lens has been replaced in a case in which the first relationship or the second relationship indicate a change in position of one of the focus lens or the zoom lens. ### Claim 3 (depends on 1) The projector according to claim 1, wherein the determination section determines that the projection lens has been replaced in a case in which one of the first relationship or second relationship is longer than a threshold value. ### Claim 4 (depends on 1) The projector according to claim 1, wherein the projection lens is provided with identification information corresponding to a type of the projection lens, and the determination section determines whether or not the projection lens has been replaced based also on a relationship between the identification information of the projection lens at the first time point and the identification information of the projection lens at the second time point. ### Claim 5 (depends on 1) The projector according to claim 1, further comprising: a detection section adapted to detect a position of the projection lens; and a measurement section adapted to measure a relationship between an actual position of the projection lens and a position of the projection lens detected by the detection section in a case in which the determination section has determined that the projection lens has been replaced. ### Claim 6 A method of controlling a projector, comprising: generating image light; projecting the image light through a projection lens which can be moved, the projection lens having a focus lens and a zoom lens; determining whether or not the projection lens has been replaced based on: a first relationship between a position of the focus lens at a first time point at which power supply to the projector is stopped, and a position of the focus lens at a second time point at which the power supply is started after the first time point, and a second relationship between a position of the zoom lens at the first time point and a position of the zoom lens at the second time point; detecting a position of the projection lens; and projecting a message for prompting a user to make the projector measure a relationship between an actual position of the projection lens and the detected position of the projection lens in a case in which it is determined that the projection lens has been replaced. ### Claim 7 A projector comprising: a drive section adapted to move a projection lens which includes a focus lens and a zoom lens; a projection section adapted to project image light through the projection lens; a storage section which stores a first threshold value; a determination section adapted to determine whether or not the projection lens has been replaced based on a first distance between a first position and a second position being longer than the first threshold value, the first position being a position of the focus lens at a first time point at which power supply to the projector is stopped, the second position being a position of the focus lens at a second time point at which the power supply is started after the first time point; a detection section adapted to detect a position of the projection lens; and a projection control section adapted to make the projection section project a message for prompting a user to make the projector measure a relationship between an actual position of the projection lens and a position of the projection lens detected by the detection section in a case in which the determination section has determined that the projection lens has been replaced. ### Claim 8 (depends on 7) The projector according to claim 7, wherein the storage section stores a second threshold value, and the determination section is adapted to determine whether or not the projection lens has been replaced based on the first distance and a second distance between a third position and a fourth position being longer than the second threshold value, the third position being a position of the zoom lens at the first time point, and the fourth position being a position of the zoom lens at the second time point.