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:
Sep. 15, 1998
Filed:
Jan. 09, 1997
Musubu Koishi, Hamamatsu, JP;
Kouichi Shirakawa, Hamamatsu, JP;
Manabu Yasukawa, Hamamatsu, JP;
Hirotoshi Terada, Hamamatsu, JP;
Hamamatsu Photonics K.K., Hamamatsu, JP;
Abstract
A semiconductor light amplifier device emits, from an exit end processed to yield no reflection, outgoing light with a light quantity corresponding to a driving signal input from a driving circuit. This outgoing light irradiates, by way of an optical system, an object to be measured; whereas the reflected light, scattered light, and diffracted light generated by the object trace back the optical system and are made incident on the exit end of the semiconductor light amplifier device in a feedback manner as return light. Accordingly, the light amplifier device performs optical amplification as the return light is incident thereon, thereby increasing the light quantity of the outgoing light. This change in light quantity of the outgoing light is detected by the light-receiving device and output therefrom as a light-receiving signal. Thus, as the relationship between the driving signal and light quantity of the outgoing light in the semiconductor light amplifier device changes in response to the light quantity of the return light, an optical characteristic of the object is measured. Therefore, a photodetector apparatus can be obtained, in which, as noise caused by the return light is suppressed, a high S/N ratio and a wide dynamic range are attained while a high-speed response is enabled.