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:
Aug. 29, 2000
Filed:
Jan. 14, 1999
Isao Asano, Tokyo, JP;
Satoshi Nakajima, Tokyo, JP;
Hochiki Corporation, Tokyo, JP;
Abstract
A D/A converter outputs analog voltage in a range of 0 to 2 V in accordance with a digital value in a range of 0 to 31 outputted from a light emission control unit, and supplies the analog voltage to a voltage/current conversion unit. Driving current outputted from the voltage/current conversion unit is controlled on a 1 mA unit basis in a range of 0 to 31 mA in accordance with the digital value. Driving current outputted from a voltage/current conversion unit is controlled on a 4 mA unit basis in a range of 0 to 124 mA, and driving current outputted from a voltage/current conversion unit is controlled on a 20 mA unit basis in a range of 0 to 620 mA. The voltage/current conversion units are on-off controlled in accordance with range designation signals, respectively. Accordingly, the luminance of the LED can be controlled in a wide range and accurately even in a low luminance level.