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:
Apr. 06, 1993
Filed:
Feb. 12, 1992
Shiro Satoh, Ogawara, JP;
Yasuhiro Osawa, Sendai, JP;
Ricoh Company, Ltd., Tokyo, JP;
Ricoh Research Institute of General Electronics Co., Ltd., Natori, JP;
Abstract
An optically functional device has a semiconductor substrate, a light receiving portion disposed on the semiconductor substrate for receiving input light, a light emitting portion disposed on the light receiving portion for emitting output light, a window disposed above the light emitting portion, through which input light and output light pass and a resistance layer made of a semiconductor for functioning as load resistance. The resistance layer is disposed at least in either place between the semiconductor substrate and the light receiving portion, or between the light receiving portion and the light emitting portion, or on the light emitting portion. The light emitting portion has a light emitting layer made of semiconductor material having an energy of forbidden band width of more than the energy of a main peak of input light. The light receiving portion has a base and a collector each of which is made of a semiconductor material having an energy of forbidden band width equal to or less than the energy of a main peak of input light. The light emitting portion is adapted to feed back a part of the output light to the light receiving portion. Thereby a nonlinear output response to input light is performed based on the feedback effect of the output light absorbed by the light receiving portion.