Browse Prior Art Database

White Balance Control Method on Liquid Crystal Display

IP.com Disclosure Number: IPCOM000114177D
Original Publication Date: 1994-Nov-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Kimura, Y: AUTHOR [+3]

Abstract

Abstract: Disclosed is a device for controlling a white balance on Thin Film Transistor Liquid Crystal Display (TFT LCD) screen. To control the color, several Cold cathode Fluorescent Lamp (CFLs) which have different color spectrum each other are used. By this mixing of color, white balance on TFT LCD screen is adjusted by both local and remote controls.

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White Balance Control Method on Liquid Crystal Display

      Abstract:  Disclosed is a device for controlling a white
balance on Thin Film Transistor Liquid Crystal Display (TFT LCD)
screen.  To control the color, several Cold cathode Fluorescent Lamp
(CFLs) which have different color spectrum each other are used.  By
this mixing of color, white balance on TFT LCD screen is adjusted by
both local and remote controls.

      Contents:  This method consists of side edge type backlight
unit to have several CFL lamps.  Each of Fig. 1 and 3 shows a plane
view of side edge type backlight.  Fig. 2 shows an A-A cross
sectional structure of the backlight.  The side edge type backlight
unit contains CFL lamps 1, lamp holders 2, light guide (acrylic
plate) 3, diffusing sheet 4, and power unit (inverter) 5.  Inverter 5
has a brightness control circuit 7 and transformers 6.  In Fig. 3,
photo sensor 8 which is used for automatic color control is shown.

      In case of local control in backlight unit, lamp current is
controlled by an inverter 5.  The ratio of mixing color is done by
controlling each CFL current independently by this inverter.  Each
CFL lamp has set up the different spectrum of lamp.  For example, one
lamp is a white lamp and has biased to green spectrum by small
amount, the other lamp has biased to red spectrum.  If the green
biased lamp gets more current than red biased lamp, then the TFT LCD
screen color (white balance) goes to a little bit of...