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Method and apparatus for downloading information from a controllable light source to a portable information device

  • US 5,535,147 A
  • Filed: 06/05/1995
  • Issued: 07/09/1996
  • Est. Priority Date: 11/22/1993
  • Status: Expired due to Fees
First Claim
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1. The method of transmitting data from a transmitter to a receiver, said transmitter including a display screen made up of a plurality of pixels arranged in a two-dimensional array that is scanned repeatedly to produce a spatially and temporally variable, two-dimensional, light image on the screen, and said receiver including a photosensor, which is much smaller than said screen, for detecting light impinging on the photosensor, said method comprising the steps of:

  • positioning the receiver so that the photosensor receives light from substantially the entirety of said screen;

    operating the transmitter to modulate the light produced by said screen so that a plurality of successive light pulses emanate from said screen during each complete scanning of said screen, each of said light pulses being produced by sequentially illuminating a sub-plurality of said pixels, said light pulses representing said data and being characterized by a predetermined pulse rate which is substantially greater than the rate at which complete scannings of said screen are performed; and

    using the receiver to detect said light pulses via said photosensor and to thereby receive said data for use by said receiver.

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