Patent ID: 8358264
Filing Date: 2013-01-22
Classification: G09G,H05B

Abstract:
1. A display device, comprising: a display panel; a backlight which illuminates said display panel; and a backlight brightness controller controlling a brightness of said backlight such that the brightness of said backlight is variable in the middle of each frame period, wherein said backlight brightness controller is configured to generate a brightness control signal in response to a picture level of an image displayed on said display panel and an environment light intensity, wherein a duty ratio of said brightness control signal is constant during said each frame period when the brightness of said backlight is controlled in response to said picture level independently of said environment light intensity, or controlled in response to said environment light intensity independently of said picture level, wherein said duty ratio of said brightness control signal is variable in the middle of said each frame period when the brightness of said backlight is controlled in response to both of said picture level and said environment light intensity, wherein a brightness control circuit is configured to determine an allowed maximum value of the brightness of said backlight when the brightness of said backlight is controlled in response to both of said picture level and said environment light intensity, wherein said brightness control circuit generates said brightness control signal such that said duty ratio of said brightness control signal is constant during each frame period, when said allowed maximum value is larger than a predetermined threshold value, and wherein said brightness control circuit generates said brightness control signal such that said duty ratio of said brightness control signal is variable in the middle of each frame period, when said allowed maximum value is smaller than said predetermined threshold value.