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:
Feb. 15, 2011
Filed:
Nov. 21, 2008
Chiu-ling Chen, Jhudong Township, Hsinchu County, TW;
Sheng-pan Huang, Changhua County, TW;
Fei-chang Hwang, Miaoli County, TW;
Chiu-Ling Chen, Jhudong Township, Hsinchu County, TW;
Sheng-Pan Huang, Changhua County, TW;
Fei-Chang Hwang, Miaoli County, TW;
Industrial Technology Research Institute, Hsinchu, TW;
Abstract
A life test device comprises an oven, a current source, a voltage meter, a control module, and a process module. A light-emitting diode (LED) is disposed in the oven. The temperature of the oven is gradually changed in a first period and remains at a set temperature in a second period. The current source provides a first current and a second current to the LED. The voltage meter measures forward voltages of the LED. The control module controls the current source to output the first or second current to the LED and controls the voltage meter to measure the forward voltages of the LED. The process module calculates a junction temperature of the LED according to the forward voltages and a variation relationship formula between the forward voltages and the temperature of the oven.