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:
Jul. 30, 1996
Filed:
Aug. 04, 1994
Syoichi Washizuka, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A luminous efficiency is estimated by obtaining a life time a of few carriers controlling the luminous efficiency. An estimation method inadiates pulsed laser light for exciting carriers in a light emitting layer by a co-focal point optical system, at a specified position of the light emitting layer of a light emitting element formed on a surface of a wafer. A life time is obtained by detecting the fluorescent light emitted from the specified position in the light emitting layer corresponding to an irradiation of the pulsed laser light and by observing a change of the fluorescent light with lapse of a time. A luminous efficiency is estimated at the specified position in the light emitting layer from the life time on the basis of a correlation of a life time and a luminous efficiency previously obtained, thereby enabling an estimation of the light emitting element at a wafer stage without destroying the wafer and without contact therewith.