# US 10,319,281 B2 · Method, apparatus and/or computer program for controlling light output of a display > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,319,281 B2 - Document ID: US10319281B2 - Status: Granted - Kind: B2 - Application number: 15/123,467 - Filed: 2015-02-19 - Published: 2017-03-30 - Granted: 2019-06-11 - Earliest claimed: 2014-03-04 - Assignees: Nokia Technologies Oy - Applicants: Nokia Technologies Oy - Inventors: Johan Bergquist - Web page: https://patentgrep.com/patent/US10319281B2 ## CPC - G09G 3/2092: {Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto (suitable for both CRT and flat panel G09G5/003; specific for a CRT G09G1/165)} - G09G 3/20: for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix {no fixed position being assigned to or needed to be assigned to the individual characters or partial characters} - G09G 2300/0456: with a reflective area and a transmissive area combined in one pixel, such as in transflectance pixels - G09G 2310/0237: Switching ON and OFF the backlight within one frame - G09G 2320/0247: Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes - G09G 2320/0285: using tables for spatial correction of display data - G09G 2320/0606: Manual adjustment - G09G 2320/0626: for control of overall brightness - G09G 2320/0666: for control of colour parameters, e.g. colour temperature - G09G 2320/0673: for control of gamma adjustment, e.g. selecting another gamma curve - G09G 2340/0435: Change or adaptation of the frame rate of the video stream - G09G 2360/141: the light conveying information used for selecting or modulating the light emitting or modulating element - G09G 2360/144: the light being ambient light - G09G 2360/145: the light originating from the display 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 A method including causing synchronization of a local time frame and refresh of a display; processing an output from a light sensor from a first time, in the local time frame, for a controlled first duration to control light output of the display at a second time, in the local time frame and after the first time, for a second duration. ## Claims ### Claim 1 A method comprising: synchronizing a local time frame and a refresh of a display with a synchronization signal, said synchronization signal starting a display period; writing an image to the display during a write duration of the display period, said write duration following said synchronization signal; processing an output from a light sensor from a first time, in the local time frame, for a first duration following said write duration to control light output of the display, said light sensor not being processed during said write duration, said light output starting at a second time, in the local time frame and after the first time, for a second duration, said light output from the display being based upon the output from the light sensor; and outputting light from the display only during the second duration, said second duration not overlapping with the write duration. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein, for an additional display period, the local time frame and the refresh of the display are synchronized. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein, for an additional display period, the output from the light sensor is processed from the first time, in the local time frame, for the first duration after said write duration to control light output of the display starting at a second time, in the local time frame and after the first time, for the second duration. ### Claim 4 (depends on 1) The method as claimed in claim 1, wherein the first time and the second time are in the same display period. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein the first time is in a display period preceding the display period of the second time. ### Claim 6 (depends on 1) The method as claimed in claim 1, wherein the display period is less than a maximum time determined by an inverse of the flicker fusion frequency. ### Claim 7 (depends on 1) The method as claimed in claim 1 wherein, in an additional display period, the first time is preceded by writing an image to the display. ### Claim 8 (depends on 1) The method as claimed in claim 1, wherein, in the display period, an end of the second duration is followed by a blanking time. ### Claim 9 (depends on 1) The method as claimed in claim 1, wherein, in an additional display period, there is the write duration for writing an image, the first duration for sensing, the second duration for illuminating, and a further duration for blanking. ### Claim 10 (depends on 1) A computer program product comprising a non-transitory computer readable storage medium bearing computer program code embodied therein for use with a computer, the computer program code comprising code for performing the method of claim 1. ### Claim 11 (depends on 1) The method as claimed in claim 1, wherein ambient light sensed during a sensing event in one display period is used to adjust the light output of the display during a light output event of the same display period, wherein each display period comprises a single write duration, a first duration for the sensing event, a second duration for the light output event for displaying an image written during the write duration of the same display period. ### Claim 12 An apparatus comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured, with the at least one processor, to cause the apparatus at least to perform: synchronizing a local time frame and a refresh of a display with a synchronization signal, said synchronization signal starting a display period; writing an image to the display during a write duration of the display period, said write duration following said synchronization signal; processing an output from a light sensor from a first time, in the local time frame, for a first duration following said write duration to control light output of the display, said light sensor not being processed during said write duration, said light output starting at a second time, in the local time frame and after the first time, for a second duration, said light output from the display being based upon the output from the light sensor; and outputting light from the display only during the second duration, said second duration not overlapping with the write duration. ### Claim 13 (depends on 12) The apparatus as claimed in claim 12, further comprising the light sensor. ### Claim 14 (depends on 13) The apparatus as claimed in claim 13, wherein the light sensor has multiple different spectral channels. ### Claim 15 (depends on 13) The apparatus as claimed in claim 13, wherein the light sensor is selected from the group consisting of an avalanche photodiode, a solid-state photo-multiplier tube, a PN-junction photodiode, and a phototransistor. ### Claim 16 (depends on 12) The apparatus as claimed in claim 12, wherein the apparatus has equivalent light paths, in opposite directions, for sensed ambient light and for emitted light. ### Claim 17 (depends on 12) The apparatus as claimed in claim 12, wherein an angular distribution of sensed ambient light is the same as an angular distribution of emitted light. ### Claim 18 (depends on 12) The apparatus as claimed in claim 12, wherein a spectral modulation of ambient light sensed by the apparatus is the same as a spectral modulation of light emitted by the apparatus. ### Claim 19 (depends on 12) The apparatus as claimed in claim 12, further comprising: an ambient light sensor for sensing ambient light; a light source for emitting light; and optics shared by the light sensor and the light source, wherein the optics provide equivalent light paths, in opposite directions, for ambient light sensed at the light sensor and for emitted light emitted from the light source. ### Claim 20 An apparatus comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured, with the at least one processor, to cause the apparatus at least to perform: switching a light source for a display off during a write duration and during a first duration of a display period, said first duration following said write duration; measuring ambient light during the first duration of the display period, said ambient light not being processed during said write duration; and switching the light source for the display on during a second duration of the display period with an adjusted light output, said adjusted light output being dependent on the measurement of ambient light made during the first duration of the display period, said second duration being after said first duration, said second duration not overlapping with the write duration and not overlapping with the first duration.