# US 2021/0240065 A1 · Projection device and calibration method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0240065 A1 - Document ID: US20210240065A1 - Status: Published application - Kind: A1 - Application number: 16/782,003 - Filed: 2020-02-04 - Published: 2021-08-05 - Earliest claimed: 2020-02-04 - Assignees: Coretronic Corporation - Applicants: Coretronic Corporation - Inventors: Ching-Feng Hsieh; Chih-Chen Chen; Hui-Chung Hung - Web page: https://patentgrep.com/patent/US20210240065A1 ## CPC - G03B 21/2053: {Intensity control of illuminating light (controlled by video signal processing H04N5/74 or H04N9/31)} - G03B 21/008: {using micromirror devices} - 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) ## Abstract A projection device includes a light source, an optical engine and a controller. The light source provides a light beam according to a setting current. The optical engine includes a light combining module, an imaging module and a projection lens. The light combining module receives the light beam to generate an illumination beam. The imaging module includes a prism, a digital micromirror device and a light sensor. The prism transmits a portion of the illumination beam to the light sensor. The digital micromirror device converts the other portion of the illumination light beam into an image beam. The light sensor disposed between the prism and the digital micromirror device receives the portion of the illumination beam to generate a brightness data. The projection lens projects the image beam. The controller dynamically adjusts the setting current to calibrate a color point of the light beam according to the brightness data. ## Claims ### Claim 1 A projection device, comprising: a light source, configured to provide a light beam according to a setting current; an optical engine, configured to receive the light beam, comprising a light combining module, an imaging module and a projection lens, wherein the light combining module is configured to receive the light beam and generate an illumination beam, the imaging module comprises: a prism, a digital micromirror device and a light sensor, wherein the prism is configured to receive the illumination beam and transmit a portion of the illumination beam to the light sensor, the digital micromirror device is configured to receive the other portion of the illumination beam transmitted from the prism and convert the other portion of the illumination light beam into an image beam, and the light sensor is disposed between the prism and the digital micromirror device, and the light sensor receives the portion of the illumination beam transmitted from the prism to generate a brightness data, and the projection lens is configured to receive the image beam transmitted from the digital micromirror device and project the image beam out of the projection device to form an image, and a controller, coupled to the light sensor and the light source, and configured to receive the brightness data, wherein the controller dynamically adjusts the setting current to calibrate a color point of the light beam emitted from the light source according to the brightness data. ### Claim 2 (depends on 1) The projection device as claimed in claim 1, wherein the digital micromirror device comprises a plurality of micro-mirrors, and the controller dynamically adjusts the setting current to calibrate the color point of the light beam emitted from the light source only when all the micro-mirrors are fully turned on. ### Claim 3 (depends on 2) The projection device as claimed in claim 2, wherein when all the micro-mirrors are fully turned on, a color of the image is normally white. ### Claim 4 (depends on 1) The projection device as claimed in claim 1, wherein the controller compares the brightness data with a predetermined value to dynamically adjust the setting current to calibrate the color point of the light beam emitted from the light source. ### Claim 5 (depends on 4) The projection device as claimed in claim 4, wherein when the brightness data is not equal to the predetermined value, the controller dynamically adjusts the setting current to calibrate the color point of the light beam emitted from the light source, and when the brightness data is equal to the predetermined value, the controller stops adjusting the setting current to calibrate the color point of the light beam emitted from the light source. ### Claim 6 (depends on 4) The projection device as claimed in claim 4, wherein when a number of times the setting current dynamically adjusted is larger than a predetermined number and the brightness data is not equal to the predetermined value, the controller stops adjusting the setting current to calibrate the color point of the light beam emitted from the light source. ### Claim 7 (depends on 1) The projection device as claimed in claim 1, wherein the controller starts to adjust the setting current to calibrate the color point of the light beam emitted from the light source under specific timing, wherein the specific timing comprises: when the projection device is activated for a predetermined period and the brightness of the light beam emitted from the light source varies within a predetermined range, when the projection device is turned off, and when the projection device is turned on manually. ### Claim 8 (depends on 1) The projection device as claimed in claim 1, wherein the controller records the setting current for a next adjustment. ### Claim 9 (depends on 1) The projection device as claimed in claim 1, wherein a color of the image projected by the projection lens is red, green or blue when the light sensor receives the portion of the illumination beam to generate the brightness data. ### Claim 10 A calibration method, adapted for a projection device, wherein the projection device comprises a light source, an optical engine and a controller, wherein the light source is configured to provide a light beam, the optical engine is configured to receive the light beam and comprises a light combining module, an imaging module and a projection lens, wherein light combining module receives the light beam and generates an illumination beam, the imaging module comprises a prism, a digital micromirror device and a light sensor, and the prism is configured to receive the illumination beam, the calibration method comprising: providing the light beam emitted from the light source according to a setting current; transmitting a portion of the illumination beam through the prism to the light sensor, and transmitting the other portion of the illumination beam through the prism to the digital micromirror device; sensing the portion of the illumination beam by the light sensor to generate a brightness data, wherein the light sensor is disposed between the prism and the digital micromirror device; and dynamically adjusting the setting current to calibrate a color point of the light beam emitted from light source by the controller according to the brightness data. ### Claim 11 (depends on 10) The calibration method as claimed in claim 10, wherein the controller dynamically adjusts the setting current to calibrate the color point of the light beam emitted from the light source only when all of a plurality of the micromirrors of the digital micromirror device are fully turned on. ### Claim 12 (depends on 11) The calibration method as claimed in claim 11, wherein the digital micromirror device receives the other portion of the illumination beam transmitted from the prism and converts the other portion of the illumination beam into an image beam, the projection lens receives the image beam and projects the image beam out of the projection device to form an image, and when all the micromirrors are fully turned on, the image projected by the projection lens is normally white. ### Claim 13 (depends on 10) The calibration method as claimed in claim 10, wherein the controller compares the brightness data with a predetermined value to dynamically adjust the setting current to calibrate the color point of the light beam emitted from the light source. ### Claim 14 (depends on 13) The calibration method as claimed in claim 13, wherein when the brightness data is not equal to the predetermined value, the controller dynamically adjusts the setting current to calibrate the color point of the light beam emitted from the light source, and when the brightness data is equal to the predetermined value, the controller stops adjusting the setting current to calibrate the color point of the light beam emitted from the light source. ### Claim 15 (depends on 13) The calibration method as claimed in claim 13, wherein when a number of times the setting current dynamically adjusted is larger than a predetermined number and the brightness data is not equal to the predetermined value, the controller stops adjusting the setting current to calibrate the color point of the light beam emitted from the light source. ### Claim 16 (depends on 10) The calibration method as claimed in claim 10, wherein the controller starts to adjust the setting current to calibrate the color point of the light beam emitted from the light source under a specific timing, wherein the specific timing comprises: when the projection device is activated for a predetermined period and the brightness of the light beam emitted from the light source varies within a predetermined range, when the projection device is turned off, and when the projection device is turned on manually. ### Claim 17 (depends on 10) The calibration method as claimed in claim 10, wherein the controller records the setting current for a next adjustment. ### Claim 18 (depends on 10) The calibration method as claimed in claim 10, wherein the digital micromirror device receives the other portion of the illumination beam transmitted from the prism and converts the other portion of the illumination beam into an image beam, the projection lens receives the image beam and projects the image beam out of the projection device to form an image, and a color of the image is red, green or blue when the light sensor receives the portion of the illumination beam to generate the brightness data.