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. 31, 1999
Filed:
May. 02, 1997
Gu-Fung David Tsuei, Sunnyvale, CA (US);
Min-Hwa Chi, Palo Alto, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A color active pixel sensor cell is formed by utilizing four photodiodes which are each covered with a layer of oxide. The thicknesses of the layers of oxide are set so that a first layer of oxide prohibits red light from entering the first photodiode, a second layer of oxide prohibits green light from entering the second photodiode, a third layer of oxide prohibits blue light from entering the third photodiode, and a fourth layer of oxide allows visible light to enter the fourth photodiode. The amount of red light received by the cell is then determined by subtracting the light energy collected by the first photodiode from the light energy collected by the fourth photodiode. Similarly, the amount of green and blue light received by the cell is determined by subtracting the light energy collected by the second and third photodiodes, respectively, from the amount of light energy collected by the fourth photodiode.