Browse Prior Art Database

Single Port Control Method for Brightness/Contrast

IP.com Disclosure Number: IPCOM000014114D
Original Publication Date: 2000-May-01
Included in the Prior Art Database: 2003-Jun-19

Publishing Venue

IBM

Abstract

Disclosed is a method for controlling the contrast or brightness of the LCD panels. Non-TFT panels such as, HPA(High Performance Addressing) , STN(Super Twisted Nematic) or DSTN(Dual Scan STN) panels require the contrast control. TFT panel requires the brightness. The present invention is the single Digital-to-Analog Converter port can control either contrast or brightness by recognizing the panel ID. The panel ID of TFT is different from that of the non-TFT(HPA, STN or DSTN). This method can save additional Digital Analog Converter or potentiometer. Fig.1 shows the hardware control mechanism. The embeded controller has two Digital Analog Converter ports. One is used for audio control. The other is used for contrast or brightness control. When TFT panel is attached, the embeded controller outputs analog brightness signal to the TFT inverter. When HPA panel is attached, the embeded controller outputs analog contrast signal to the HPA panel.