The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 09, 2001
Filed:
Nov. 16, 1999
Applicant:
Inventors:
Assignee:
NHK Spring Co., Ltd., , JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B 2/744 ;
U.S. Cl.
CPC ...
G02B 2/744 ;
Abstract
The object to be identified is affixed with an identification medium comprising a reflective layer consisting of a reflective hologram or diffraction grating. The high polymer cholesteric liquid crystal provides an inexpensive identification medium, and the use of the second light receiving unit for providing a reference signal provides a high S/N output signal which is highly distinct and resistant to the contamination of the identification medium. Also, the elimination of the need for expensive optical elements such as beam splitters also contributes to the reduction of cost.