# US 2022/0044489 A1 · Flicker mitigation when toggling eyepiece display illumination in augmented reality systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0044489 A1 - Document ID: US20220044489A1 - Status: Published application - Kind: A1 - Application number: 17/510,174 - Filed: 2021-10-25 - Published: 2022-02-10 - Earliest claimed: 2018-07-24 - Assignees: Magic Leap, Inc. - Applicants: Magic Leap, Inc. - Inventors: Arno Leon Konings; Mihailo Slobodan Zivkovic; Jose Felix Rodriguez; Ricardo Martinez Perez - Web page: https://patentgrep.com/patent/US20220044489A1 ## CPC - G06T 19/006: {Mixed reality (object pose determination, tracking or camera calibration for mixed reality G06T7/00)} - G02B 27/0101: {characterised by optical features (G02B27/0172 takes precedence)} - G02B 27/0172: {characterised by optical features} - G02B 30/00: Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images (in microscopes G02B21/22) - G06F 3/011: {Arrangements for interaction with the human body, e.g. for user immersion in virtual reality (blind teaching G09B21/00)} - G06F 3/013: {Eye tracking input arrangements (G06F3/015 takes precedence)} - G06T 7/70: Determining position or orientation of objects or cameras (camera calibration G06T7/80) - G06T 13/40: of characters, e.g. humans, animals or virtual beings - G02B 2027/0118: {comprising devices for improving the contrast of the display / brillance control visibility} - G02B 2027/014: {comprising information/image processing systems} - G02B 2027/0141: {characterised by the informative content of the display} - G02B 2027/0178: {Eyeglass type (eyeglass details G02C)} - G06F 2203/012: Walk-in-place systems for allowing a user to walk in a virtual environment while constraining him to a given position in the physical environment - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract An augmented reality display system is disclosed. The system can include a partially transparent eyepiece, an ambient light sensor, and an image input device. The image input device can include a light source and a spatial light modulator. The system can also include a controller that determines that no virtual content is being displayed to the user and compares the ambient light to display light to determine if a light source shutoff criterion is satisfied. If the light source shutoff criterion is satisfied, the controller can turn off the light source. ## Claims ### Claim 1 An augmented reality display system comprising: an eyepiece display configured to be worn by a user, the eyepiece display being at least partially transparent so as to transmit ambient light toward the eye of the user; an ambient light sensor configured to detect the ambient light; an image input device capable of inputting virtual content into the eyepiece display, the image input device comprising a light source and a spatial light modulator illuminated by the light source; and a controller, wherein the eyepiece display is configured to emit display light, and wherein the controller is configured to: determine that no virtual content is being displayed to the user; compare the ambient light to the display light to determine if a light source shutoff criterion is satisfied, and turn off the light source if the light source shutoff criterion is satisfied. ### Claim 2 (depends on 1) The augmented reality display system of claim 1, wherein the controller is configured to compare the ambient light to the display light using on one or more ambient light values measured by the ambient light sensor and one or more display light values. ### Claim 3 (depends on 2) The augmented reality display system of claim 2, wherein the controller is configured to determine the one or more display light values based on the state of the light source. ### Claim 4 (depends on 2) The augmented reality display system of claim 2, further comprising a display light sensor, wherein the controller is configured to measure the one or more display light values using the display light sensor. ### Claim 5 (depends on 4) The augmented reality display system of claim 4, wherein the display light sensor is configured to detect luminance of the display light. ### Claim 6 (depends on 5) The augmented reality display system of claim 5, wherein the display light sensor is configured to detect luminance and chromaticity of the display light. ### Claim 7 (depends on 1) The augmented reality display system of claim 1, wherein the ambient light sensor is configured to detect luminance of the ambient light. ### Claim 8 (depends on 7) The augmented reality display system of claim 7, wherein the ambient light sensor is configured to detect luminance and chromaticity of the ambient light. ### Claim 9 (depends on 1) The augmented reality display system of claim 1, wherein the ambient light sensor is positioned so as to detect the ambient light before it passes through the eyepiece display. ### Claim 10 (depends on 1) The augmented reality display system of claim 1, wherein the ambient light sensor is positioned so as to detect filtered ambient light that has passed through the eyepiece display. ### Claim 11 (depends on 1) The augmented reality display system of claim 1, wherein the controller is configured to compare unfiltered ambient light to the display light. ### Claim 12 (depends on 1) The augmented reality display system of claim 1, wherein the controller is configured to compare filtered ambient light that has passed through the eyepiece display to the display light. ### Claim 13 (depends on 1) The augmented reality display system of claim 1, wherein the shutoff criterion is based on luminance. ### Claim 14 (depends on 13) The augmented reality display system of claim 13, wherein the shutoff criterion comprises a just-noticeable luminance difference. ### Claim 15 (depends on 14) The augmented reality display system of claim 14, wherein the just-noticeable luminance difference comprises a percentage of the luminance of filtered ambient light. ### Claim 16 (depends on 15) The augmented reality display system of claim 15, wherein the controller is further configured to determine the luminance of the filtered ambient light based on the luminance of unfiltered ambient light that has not passed through the eyepiece display and based on information indicative of the filtering effect of the eyepiece display on the unfiltered ambient light. ### Claim 17 (depends on 15) The augmented reality display system of claim 15, wherein the controller is further configured to determine if the light source shutoff criterion is satisfied based on a difference between the just-noticeable luminance difference and the average luminance of the display light when no virtual content is being displayed. ### Claim 18 (depends on 1) The augmented reality display system of claim 1, wherein the shutoff criterion is based on chromaticity. ### Claim 19 (depends on 18) The augmented reality display system of claim 18, wherein the shutoff criterion comprises a just-noticeable color difference. ### Claim 20 (depends on 19) The augmented reality display system of claim 19, wherein the color difference comprises the International Commission on Illumination CIE76 color difference. ### Claim 21 (depends on 19) The augmented reality display system of claim 19, wherein determining if the light source shutoff criterion is satisfied comprises calculating a distance between a point in a color space that corresponds to the color of filtered ambient light that has passed through the eyepiece display and a point in the color space that corresponds to a combination of the color of the display light, when no virtual content is being displayed to the user, and the color of the filtered ambient light. ### Claim 22 (depends on 21) The augmented reality display system of claim 21, wherein the controller is further configured to determine the color of the filtered ambient light based on the color of unfiltered ambient light that has not passed through the eyepiece display and based on information indicative of the filtering effects of the eyepiece display on the unfiltered ambient light. ### Claim 23 (depends on 21) The augmented reality display system of claim 21, wherein the controller is further configured to determine the color of the display light by compensating for the effect of the filtered ambient light on a measurement of the display light. ### Claim 24 (depends on 21) The augmented reality display system of claim 21, wherein the color space comprises the CIE 1931 RGB color space, the CIE 1931 XYZ color space, the CIE 1976 L*u*v* color space, or the CIE 1976 L*a*b* color space. ### Claim 25 (depends on 1) The augmented reality display system of claim 1, wherein the controller is further configured to reduce luminance of the light source before turning off the light source. ### Claim 26 (depends on 25) The augmented reality display system of claim 25, wherein the controller is configured to reduce the luminance of the light source at a rate that is less than one just-noticeable luminance difference or one just-noticeable color difference per eye integration period. ### Claim 27 (depends on 1) The augmented reality display system of claim 1, wherein the shutoff criterion is that the display light exceeds a predetermined threshold. ### Claim 28 (depends on 27) The augmented reality display system of claim 27, wherein the predetermined threshold comprises a percentage of the ambient light.