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:
Dec. 02, 1997
Filed:
Oct. 03, 1995
Hiroaki Misawa, Tokushima, JP;
Central Glass Company, Limited, Yamaguchi, JP;
Abstract
The invention relates to a three-dimensional optical memory element. This element is made of glass and includes: a glass matrix which has a first refractive index; and a plurality of spots which are three-dimensionally distributed in the glass matrix and each of which has a second refractive index different from the first refractive index. The element is prepared by condensing a pulsed laser beam to focal points in the element so as to prepare, at the focal points, the spots corresponding to the focal points. Each focal point has a diameter which is approximately equal to a wavelength of the pulsed laser beam. The element has a sufficient weatherability and a sufficient resistance to heat and light. It is possible to write information at each spot having a diameter equal to or shorter than the wavelength of the laser beam, with high density and good contrast.