×

Method and apparatus for preventing display screen burn-in

  • US 6,262,772 B1
  • Filed: 11/23/1998
  • Issued: 07/17/2001
  • Est. Priority Date: 11/23/1998
  • Status: Expired due to Fees
First Claim
Patent Images

1. An apparatus for automatically eliminating horizontal and vertical black bands from the border of a displayed video image, said apparatus comprising:

  • first means for performing a first detection of the occurrence of a black level in an input video signal for at least n lines at the beginning and end of a frame in the video signal;

    second means for performing a second detection of the occurrence of a black level in an input video signal for at least m pixels at the beginning and end of each line in the video signal;

    means for vertically up-converting the lines in the video signal in dependence on said first detection; and

    means for horizontally expanding the lines in the video signal in dependence on said detection, wherein said apparatus further comprises;

    an input for receiving a video signal;

    a demultiplexer having an input coupled to said input, a first output coupled to said vertically up-converting means, a second output coupled to said horizontal expanding means, a third output, and a control input;

    a multiplexer having a first input coupled to an output of said vertically up-converting means, a second input coupled to an output of said horizontal expanding means, a third input coupled to the third output of said de-multiplexer, an output and a control input;

    an output coupled to an output of said multiplexer for supplying an output video signal in which any black bands are suppressed; and

    a black level detector comprising said first and second detection means, said black level detector having an input coupled to said input of said apparatus and an output coupled to the control inputs of said demultiplexer and said multiplexer, wherein said black level detector switches said demultiplexer and said multiplexer to said first output and said first input, respectively, on said first detection, to said second output and said first input, respectively, on said second detection, and otherwise to said third output and said third input, respectively.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×