US 11,842,702 B2
Liquid crystal display apparatus capable of changing backlight emission brightness
Koji Mito, Kanagawa (JP); and Yasuo Suzuki, Kanagawa (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Oct. 27, 2021, as Appl. No. 17/511,797.
Claims priority of application No. 2020-189430 (JP), filed on Nov. 13, 2020; and application No. 2021-140204 (JP), filed on Aug. 30, 2021.
Prior Publication US 2022/0157267 A1, May 19, 2022
Int. Cl. G09G 3/36 (2006.01); G09G 3/00 (2006.01)
CPC G09G 3/00 (2013.01) [G09G 2320/066 (2013.01); G09G 2320/0626 (2013.01); G09G 2354/00 (2013.01); G09G 2360/16 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A liquid crystal display apparatus comprising:
a liquid crystal panel;
an input interface for inputting data of a first image;
a backlight module which is configured to irradiate light to the liquid crystal panel and of which emission brightness is changeable; and
at least one memory and at least one processor which function as:
an estimating unit configured to estimate brightness of light to be irradiated from the backlight module to the liquid crystal panel;
a correcting unit configured to correct the first image to a second image based on the brightness estimated by the estimating unit, a contrast of the liquid crystal panel, and a target contrast so that a brightness error with respect to a display brightness in a case where the first image is displayed with the target contrast is suppressed; and
a control unit configured to control transmittance of the liquid crystal panel based on data of the second image, wherein
in a case where a value obtained by normalizing a gradation value of the first image to 0 to 1 is denoted by Vin, the target contrast is expressed as Ct to 1, the contrast of the liquid crystal panel is expressed as Cp to 1, a value obtained by normalizing the brightness estimated by the estimating unit to 0 to 1 is denoted by Le, and a gamma value of the liquid crystal panel is denoted by pg, the correcting unit calculates a gradation value of the second image by multiplying the gradation value of the first image by a correction coefficient Gt calculated using the following formula

OG Complex Work Unit Math