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
Document File: 2 page(s) / 41K

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.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Single Port Control Method for Brightness/Contrast

    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.

····

        Fig.2 shows the sofware control concept. The BIOS table has the digital
parameter for both brightness and contrast control.

       There is only one Digital-to-Analog Converter port for brightness/contrast
analog signal output.

1

[This page contains 2 pictures or other non-text objects]

Page 2 of 2

·····

             Fig.3 shows the flow chart of this brightness/contrast control by
using single Digital-to-Analog Converter port.

·····

2

[This page contains 4 pictures or other non-text objects]