DISPLAY DRIVER

• US 20140247291A1
• Filed: 05/13/2014
• Published: 09/04/2014
• Est. Priority Date: 11/21/2006
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Renesas Electronics Corporation
• Inventors: TAKADA, Naoki, KUDO, Yasuyuki, KUROKAWA, Yoshiki, SAKAMAKI, Goro
• Granted Patent: US 9,626,916 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/0653 Controlling or limiting the speed of brightness adjustment of the illumination source
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 5/10 Intensity circuits

Abstract

In a display driver, a first backlight control unit using a histogram and a second backlight control unit using an optical sensor can be used in combination. The display driver includes a PWM generating unit setting a control signal value consisting of a product of a luminance rate of X % and a luminance rate of Y % as a luminance rate of a control signal for controlling a backlight with respect to maximum backlight luminance when a luminance rate of a control signal obtained by first backlight control with respect to the maximum backlight luminance is X % and a luminance rate of a control signal obtained by second backlight control with respect to the maximum backlight luminance is Y %.

Claims

1. A display control system comprising:

a graphic RAM which stores a display data;

an optical sensor which senses external-light luminance and outputs an illuminance value;

a control unit which generates a backlight control signal based on the display data and the illuminance value.

2. The display control system according to claim 1, further comprising:

a Pulse Width Modulation (PWM) signal generated unit which receives the backlight control signal and provides a PWM control signal based on the backlight control signal; and

a backlight module which receives the PWM control signal