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Invisible information recorded medium

  • US 5,503,904 A
  • Filed: 01/19/1994
  • Issued: 04/02/1996
  • Est. Priority Date: 01/19/1993
  • Status: Expired due to Term
First Claim
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1. An invisible information recorded medium comprising a recording medium having an identification mark recorded thereon, said identification mark being composed of a first region and a second region, whereinsaid first region has a higher reflectance than a reflectance of said medium at a near infrared wavelength,said second region has a lower reflectance than the reflectance of said medium at said near infrared wavelength, andsaid first region and said second region do not overlap each other,wherein the reflectance of said medium is represented by a reflectance on a portion at which the identification mark is not recorded.

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