# US 12,217,722 B2 · Frequency compensation for a display > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,217,722 B2 - Document ID: US12217722B2 - Status: Granted - Kind: B2 - Application number: 18/435,708 - Filed: 2024-02-07 - Published: 2024-05-30 - Granted: 2025-02-04 - Earliest claimed: 2024-02-05 - Assignees: Google Inc. - Applicants: Google LLC - Inventors: Hyunchul Kim; Chien-Hui Wen; Ken Kok Foo - Web page: https://patentgrep.com/patent/US12217722B2 ## CPC - G09G 5/02: characterised by the way in which colour is displayed {(details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607)} - G09G 2320/0233: Improving the luminance or brightness uniformity across the screen - 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) ## Abstract Techniques and apparatuses are described that perform frequency compensation for a display. In aspects, a first uniformity of multiple regions of the display can be measured at a reference frequency. The display can then be driven at a second frequency and a second uniformity of the multiple regions of the display can be measured. The differences between the first and second uniformity can then be used to generate a compensation mask. XYZ domain data from the first and second uniformity measurements can be used to generate a color model characterization. The color model characterization can be used to convert the XYZ domain data into RGB data when the display is driven at the second frequency to compensate for the differences in uniformity across the multiple regions of the display. ## Claims ### Claim 1 A method comprising: driving a display at a first frequency with a control signal via a device controller, the first frequency being a reference frequency; measuring a first uniformity, at the first frequency, of multiple regions of the display in an XYZ domain at the reference frequency; driving the display at a second frequency with the control signal via the device controller; measuring a second uniformity, at the second frequency, of the multiple regions of the display in the XYZ domain; generating a compensation mask to compensate for a difference between the second uniformity and the first uniformity; generating a color model characterization based on the difference between the second uniformity and the first uniformity to generate a conversion formula; converting data associated with the XYZ domain to Red Green Blue (RGB) data using the conversion formula; and applying the RGB data and the compensation mask to the display with the display being driven at the second frequency to compensate for the difference between the first uniformity and the second uniformity. ### Claim 2 (depends on 1) The method of claim 1, wherein the multiple regions of the display do not have a difference in uniformity when driven at the first frequency, and wherein a first region of the multiple regions of the display has a 3-10% difference in uniformity compared to a second region of the multiple regions when the display is driven at the second frequency. ### Claim 3 (depends on 1) The method of claim 1, wherein the first frequency is a high speed frequency, the display is manufactured to provide uniformity across the multiple regions of the display, and the second frequency is a normal or low speed frequency. ### Claim 4 (depends on 1) The method of claim 1, wherein the first frequency is 120 hertz (Hz) and the second frequency is 60 Hz or 90 Hz. ### Claim 5 (depends on 1) The method of claim 1, further comprising: driving the display at a third frequency; and measuring a third uniformity, at the third frequency, of the multiple regions of the display in the XYZ domain, wherein the compensation mask compensates for differences between the third uniformity and the first uniformity. ### Claim 6 (depends on 1) The method of claim 1, wherein the measuring of the first uniformity and the second uniformity is accomplished via a two dimensional camera associated with the device controller. ### Claim 7 (depends on 1) The method of claim 1, wherein the display is employed as a part of a smartphone and is driven at the first frequency for a period of time and at the second frequency for a different period of time. ### Claim 8 (depends on 1) The method of claim 1, wherein the RGB data and the compensation mask are applied to multiple displays being driven at the second frequency.