# US 11,994,424 B2 · Method for measuring ambient light and corresponding integrated device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,994,424 B2 - Document ID: US11994424B2 - Status: Granted - Kind: B2 - Application number: 17/569,171 - Filed: 2022-01-05 - Published: 2022-05-19 - Granted: 2024-05-28 - Earliest claimed: 2020-11-17 - Assignees: STMicroelectronics (Crolles 2) SAS; STMicroelectronics (Research & Development) Limited; STMicroelectronics (Grenoble 2) SAS - Applicants: STMicroelectronics (Research & Development) Limited; STMicroelectronics (Grenoble 2) SAS; STMicroelectronics (Crolles 2) SAS - Inventors: Pierre Malinge; Frédéric Lalanne; Jeffrey M. Raynor; Nicolas Moeneclaey - Web page: https://patentgrep.com/patent/US11994424B2 ## CPC - G01J 1/4204: {with determination of ambient light (solar light G01J2001/4266)} - G01J 1/46: using a capacitor - G09G 3/3225: using an active matrix - H04N 25/53: Control of the integration time - H04N 25/77: Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components - H05B 47/105: in response to determined parameters - G09G 2320/0626: for control of overall brightness - G09G 2360/144: the light being ambient light - H05B 47/11: by determining the brightness or colour temperature of ambient light - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract In an embodiment a method for measuring ambient light includes successively synchronizing optical signal acquisition phases with extinction phases of a disruptive light source, wherein the disruptive light source periodically provides illumination phases and the extinction phases, accumulating, in each acquisition phase, photo-generated charges by at least one photosensitive pixel comprising a pinned photodiode, wherein an area of the pinned photodiode is less than or equal to 1/10 of an area of the at least one photosensitive pixel, transferring, for each pixel, the accumulated photo-generated charges to a sensing node, converting, for each pixel, the transferred charges to a voltage at a voltage node and converting, for each pixel, the transferred charges to a digital number. ## Claims ### Claim 1 A method for measuring ambient light, the method comprising: successively synchronizing optical signal acquisition phases with extinction phases of a disruptive light source, wherein the disruptive light source periodically provides illumination phases and the extinction phases; accumulating, in each acquisition phase, photo-generated charges by at least one photosensitive pixel comprising a pinned photodiode, wherein an area of the pinned photodiode is less than or equal to 1/10 of an area of the at least one photosensitive pixel; transferring, for each pixel, the accumulated photo-generated charges to a sensing node; converting, for each pixel, the transferred charges to a voltage at a voltage node; and converting, for each pixel, the transferred charges to a digital number. ### Claim 2 (depends on 1) The method according to claim 1, further comprising discharging the at least one pixel of parasitic charges accumulated outside the acquisition phase during a reset at a beginning of each acquisition phase. ### Claim 3 (depends on 2) The method according to claim 2, wherein the reset comprises lowering an electrostatic potential barrier at a transfer gate and connecting the sensing node to a first reference voltage thereby enabling diffusion of the parasitic charges to the first reference voltage. ### Claim 4 (depends on 1) The method according to claim 1, wherein transferring the accumulated photo-generated charges to the sensing node comprises lowering an electrostatic potential barrier of a transfer gate thereby enabling diffusion of the photo-generated charges to the sensing node. ### Claim 5 (depends on 1) The method according to claim 1, wherein transferring the accumulated photo-generated charges further comprising transferring it from the sensing node to an input of a transimpedance amplifier and a capacitive element. ### Claim 6 An integrated ambient light sensing device comprising: at least one photosensitive pixel comprising a pinned photodiode, wherein an area of the pinned photodiode is less than or equal to 1/10 of an area of the at least one photosensitive pixel; a conversion circuit electrically connected to the photosensitive pixel via a sensing node; and a controller configured to: successively synchronize optical signal acquisition phases with extinction phases of a disruptive light source, wherein the disruptive light source periodically provides illumination phases and the extinction phases; accumulate, in each acquisition phase, photo-generated charges by the at least one photosensitive pixel; and transfer the accumulated photo-generated charges to the sensing node, wherein the conversion circuit is configured to convert the transferred charges to a digital number. ### Claim 7 (depends on 6) The device according to claim 6, wherein the area of the pinned photodiode is less than or equal to 1/100 of the area of the at least one photosensitive pixel. ### Claim 8 (depends on 6) The device according to claim 6, wherein each pixel includes a transfer gate between the pinned photodiode and the sensing node, and wherein the controller is configured to control the transfer of the photo-generated charges by generating a potential on the transfer gate adapted to lower an electrostatic potential barrier and enable diffusion of the photo-generated charges to the sensing node and then to the conversion circuit. ### Claim 9 (depends on 8) The device according to claim 8, wherein the transfer gate is part of a transistor. ### Claim 10 (depends on 8) The device according to claim 8, wherein the controller is further configured to discharge the at least one pixel of parasitic charges accumulated outside the acquisition phase during a reset at a beginning of each acquisition phase. ### Claim 11 (depends on 6) The device according to claim 6, wherein the conversion circuit comprises a transimpedance amplifier connected to an analog to digital converter, and wherein the transimpedance amplifier is loop around via a loop comprising a capacitive element. ### Claim 12 (depends on 11) The device according to claim 11, wherein the conversion circuit comprises a single transimpedance amplifier with a single capacitive element. ### Claim 13 (depends on 6) The device according to claim 6, wherein the at least one pixel comprises a plurality of pixels arranged in rows and columns. ### Claim 14 (depends on 13) The device according to claim 13, wherein the controller is configured to activate or de-active a transfer gate of each of the pixels. ### Claim 15 (depends on 6) A system comprising: a light-emitting display screen; the device according to claim 6; and a camera, wherein the light-emitting display screen is the disruptive light source. ### Claim 16 An integrated ambient light sensing device comprising: an array of photosensitive pixels, each pixel comprising a pinned photodiode; a conversion circuit electrically connected to the photosensitive pixels via sensing nodes; and a controller configured to: successively synchronize optical signal acquisition phases with extinction phases of a disruptive light source, wherein the disruptive light source periodically provides illumination phases and the extinction phases; accumulate, in each acquisition phase, photo-generated charges by at least one photosensitive pixel; and transfer the accumulated photo-generated charges to the sensing node, wherein the conversion circuit comprises a single transimpedance amplifier looped around by a loop, the loop comprising a single capacitive element, and an analog to digital converter. ### Claim 17 (depends on 16) The device according to claim 16, wherein the controller is configured to activate or de-active a transfer gate of each of the pixels. ### Claim 18 (depends on 16) The device according to claim 16, wherein an area of the pinned photodiode is less than or equal to 1/10 of an area of the at least one photosensitive pixel. ### Claim 19 (depends on 16) The device according to claim 16, wherein an area of the pinned photodiode is less than or equal to 1/100 of an area of the at least one photosensitive pixel. ### Claim 20 A method for measuring ambient light, the method comprising: successively synchronizing optical signal acquisition phases with extinction phases of a disruptive light source, wherein the disruptive light source periodically provides illumination phases and the extinction phases; accumulating, in each acquisition phase, photo-generated charges by at least one photosensitive pixel comprising a pinned photodiode; transferring the accumulated photo-generated charges to an integration node; and integrating, for each pixel, the transferred charges on the integration node during a series of the successive acquisition phases. ### Claim 21 An integrated ambient light sensing device comprising: at least one photosensitive pixel comprising a pinned photodiode; an integrator circuit electrically connected to the photosensitive pixel via an integration node; and a controller configured to: successively synchronize optical signal acquisition phases with extinction phases of a disruptive light source, wherein the disruptive light source periodically provides illumination phases and the extinction phases; accumulate, in each acquisition phase, photo-generated charges by the at least one photosensitive pixel; and transfer the accumulated photo-generated charges to the integration node, wherein the integration node is configured to integrate the transferred charges during a series of the successive acquisition phases.