Browse Prior Art Database

Liquid Crystal Display having Internal Video Signals Generator for Self-Diagnostics

IP.com Disclosure Number: IPCOM000116297D
Original Publication Date: 1995-Aug-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Itoh, H: AUTHOR [+4]

Abstract

Disclosed is a Liquid Crystal Display (LCD) which have internal video signals generator for self diagnostic. Without input of external video signals, this LCD panel can do self-diagnostic tests by using internal video signals generator.

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This is the abbreviated version, containing approximately 71% of the total text.

Liquid Crystal Display having Internal Video Signals Generator for
Self-Diagnostics

      Disclosed is a Liquid Crystal Display (LCD) which have internal
video signals generator for self diagnostic.  Without input of
external video signals, this LCD panel can do self-diagnostic tests
by using internal video signals generator.

      The self-diagnostic test function detail follows.  As
self-diagnostic video screen, there are "Geometrical pattern", "Gray
scaled bars", "Black and White stripes", "Black and White windows",
"Periodically Loop of those patterns", for example:
  1.  Diagnostic for about 3000 connection among PCBs, X/Y-Driver,
       LCD glass
      -> by using "Geometrical pattern (Checker, H/VSYNC, R/G/B
          Full screen)".
  2.  Diagnostic for X/Y-Driver ICs
      -> by using "Gray scaled bars", "Geometrical pattern".
  3.  Diagnostic for FOS quality
      -> by using "Black and White stripes", "Black and White
windows",
          "Gray scaled bars", "Geometrical pattern", etc.
  4.  For Long run test
      -> by using "Periodically Loop of those patterns".

      The Figure shows the internal logic circuit of this LCD.  The
portion marked with *1 is the internal video signals generator
circuit.

      In case of normal display operation, the internal video
generator circuit is disabled, but LCD logic works based on external
video signals.  As a result, normal video will be displayed o...