# US 2021/0241675 A1 · Display unit illumination > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0241675 A1 - Document ID: US20210241675A1 - Status: Published application - Kind: A1 - Application number: 17/048,733 - Filed: 2018-10-18 - Published: 2021-08-05 - Earliest claimed: 2018-10-18 - Assignees: Hewlett-Packard Development Company, L.P. - Applicants: Hewlett-Packard Development Company, L.P. - Inventors: Lee Atkinson - Web page: https://patentgrep.com/patent/US20210241675A1 ## CPC - G09G 3/22: using controlled light sources - G09G 3/3406: {Control of illumination source (illumination devices structurally associated with liquid crystal cells G02F1/1336)} - 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 2310/0237: Switching ON and OFF the backlight within one frame - G09G 2310/061: for resetting or blanking - G09G 2310/08: Details of timing specific for flat panels, other than clock recovery - G09G 2320/0247: Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes - G09G 2320/064: by time modulation of the brightness of the illumination source - 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 Examples of illumination of display units are described. In an example, a display unit is illuminated for a first portion of a time period to display a display frame. The time period is a threshold time period. Further, the display unit is illuminated for an additional portion of the time period after the time period in response to determination of a frame absence condition at an end of the time period. ## Claims ### Claim 1 A method of illumination of a display unit, the method comprising: causing, by a processing resource, illumination of the display unit for a first portion of a time period to display a display frame, the time period being a threshold time period; determining, by a processing resource, a frame absence condition at an end of the time period; and causing, by a processing resource, illumination of the display unit for an additional portion of the time period after the time period in response to the determination of the frame absence condition. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the additional portion is smaller than the first portion. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein the illumination for the additional portion of the time period in response to the determination of the frame absence condition is caused at the end of the time period after every second portion of the time period until a subsequent display frame is rendered. ### Claim 4 (depends on 3) The method as claimed in claim 3, further comprising: causing, by the processing resource, illumination of the display unit for the first portion of the time period in response to rendering of the subsequent display frame. ### Claim 5 (depends on 3) The method as claimed in claim 3, wherein the second portion is smaller than the first portion and greater than the additional portion. ### Claim 6 (depends on 1) The method as claimed in claim 1, further comprising: causing, by the processing resource, illumination of the display unit for the first portion of the time period in response to rendering of a subsequent display frame, wherein the illumination for the additional portion of the time period in response to the determination of the frame absence condition is caused at the end of the first portion of the time period for which the subsequent display frame is displayed. ### Claim 7 (depends on 6) The method as claimed in claim 6, wherein the illumination for the additional portion at the end of the first portion is caused multiple times based on a time delay in receiving the subsequent display frame from the end of the time period. ### Claim 8 A system comprising: a display unit; a processor coupled to the display unit; and a memory coupled to the processor, the memory storing instructions executable by the processor to: cause illumination of the display unit for a first portion of a time period in response to rendering of a display frame, the time period being a threshold time period; determine a frame absence condition at an end of the time period; and in response to the determination of the frame absence condition, cause illumination of the display unit, at the end of the time period, for an additional portion of the time period after every second portion of the time period, until a subsequent display frame is rendered. ### Claim 9 (depends on 8) The system as claimed in claim 8, wherein the memory further stores instructions executable by the processor to: cause illumination of the display unit for the first portion of the time period in response to rendering the subsequent display frame to display the subsequent display frame. ### Claim 10 (depends on 8) The system as claimed in claim 8, the second portion is smaller than the first portion and greater than the additional portion. ### Claim 11 (depends on 8) The system as claimed in claim 8, wherein: the first portion is in a range of 25% of the time period to 35% of the time period; the second portion is in a range of 9% of the time period to 11% of the time period; and the additional portion is in a range of 2.5% of the time period to 3.5% of the time period. ### Claim 12 A non-transitory computer-readable medium comprising computer-readable instructions, which, when executed by a processor, cause the processor to: cause illumination of a display unit for a first portion of a time period to display a first display frame, the time period being a threshold time period; determine a frame absence condition at an end of the time period after displaying the first display frame; and cause illumination of the display unit for the first portion of the time period and an additional portion of the time period in response to rendering of a second display frame and the determination of the frame absence condition. ### Claim 13 (depends on 12) The non-transitory computer-readable medium as claimed in claim 12, wherein the additional portion is smaller than the first portion. ### Claim 14 (depends on 12) The non-transitory computer-readable medium as claimed in claim 12, wherein the illumination for the additional portion at the end of the first portion is caused multiple times based on a time delay in receiving the second display frame from the end of the time period. ### Claim 15 (depends on 14) The non-transitory computer-readable medium as claimed in claim 14, wherein the multiple times is equal to Integer[TD/T2], TD being the time delay and T2 being a second portion of the time period smaller than the first portion and greater than the additional portion.