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Thin-Film Transistor/Liquid Crystal Display Interface with Multiple Digital-to-Analog Converters

IP.com Disclosure Number: IPCOM000114801D
Original Publication Date: 1995-Feb-01
Included in the Prior Art Database: 2005-Mar-29
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Kobayashi, Y: AUTHOR [+3]

Abstract

This invention disclosure is concerned with interface between a Thin-Film Transistor/Liquid Crystal Display (TFT/LCD) and a graphic subsystem, and describes a method and its hardware implementation that realize high-resolution and high-quality TFT-LCD without using special high-frequency (i.e., high-cost) hardware technologies.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 68% of the total text.

Thin-Film Transistor/Liquid Crystal Display Interface with Multiple
Digital-to-Analog Converters

      This invention disclosure is concerned with interface between a
Thin-Film Transistor/Liquid Crystal Display (TFT/LCD) and a graphic
subsystem, and describes a method and its hardware implementation
that realize high-resolution and high-quality TFT-LCD without using
special high-frequency (i.e., high-cost) hardware technologies.

      Conventional methods use a single DAC for each of the three
colors (R, G, and B).  Thus, with the conventional interface,
high-resolution TFT/LCD requires a very high-frequency (> 100 MHz)
dot-clock.  On the other hand, this invention provides a wide signal
bandwidth without increasing the dot-clock frequency.

      Fig. 1 shows a block diagram of the interface, which consists
of a controller, multiple Digital-to-Analog Converters (DACs) (DAC1,
..., DACn), and multiple source drivers (Driver 11, ..., Driver 1m,
..., Driver n1, ..., Driver nm).  In this invention, a TFT/LCD panel
is divided into vertical segments (Segment 1, ..., Segment n), which
correspond to the multiple DACs.  So as to reduce the number of
signal lines between the source drivers and the DACs as well as
between the DACs and the controller, the controller multiplexes the
data for the three colors, as shown in Fig. 1.

      An Micro-Processor Unit (MPU) or a graphic accelerator writes
image data into a set of Video Random Access Memories (VRAMs).  Then,...