Patent · US Expired

Invisible information recorded medium

US5503904A · kind A · utility

42Cited by
28References
17Claims
0Family size

Assignee

Inventors

Key dates

Filing dateJan 19, 1994
Grant dateApr 2, 1996
Priority date
Expiry dateJan 19, 2014

Classification

  • Technology area (CPC Y)Emerging Cross-Sectional Technologies
  • CPC primaryY10T428/24942
  • WIPO fieldAudio-visual technology
  • WIPO sectorElectrical engineering

Abstract

An object of the present invention is to provide an invisible information recorded medium having an identification mark. In order to achieve the object, an invisible information recorded medium is provided having an identification mark recorded thereon, the identification mark being composed of a region having a high reflectance and a region having a low reflectance as compared with the reflectance of the medium in the same near infrared ray region.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.