(12) United States Patent ao) Patent No.: Us 7,787,033 B2
Rossi et al. (45) Date of Patent: *Aug. 31,2010
(54) APPARATUS AND METHOD FOR
DETERMINING TEMPERATURE OF AN
ACTIVE PIXEL IMAGER AND CORRECTING
TEMPERATURE INDUCED VARIATIONS IN
(75) Inventors: Giuseppe Rossi, Pasadena, CA (US);
Gennadiy A. Agranov, Sunland, CA
(73) Assignee: Aptina Imaging Corporation, Grand
( * ) Notice: Subject to any disclaimer, the term of this
patent is extended or adjusted under 35
U.S.C. 154(b) by 1398 days.
This patent is subject to a terminal dis-
(21) Appl.No.: 11/217,350
(22) Filed: Sep. 2, 2005
(65) Prior Publication Data
US 2005/0285954 Al Dec. 29, 2005
Related U.S. Application Data
(63) Continuation of application No. 10/290,397, filed on Nov. 8, 2002, now Pat. No. 6,974,973.
(51) Int. CI.
H01L 31/058 (2006.01)
(52) U.S. CI 348/244; 257/467; 257/469
(58) Field of Classification Search 348/241,
348/243-5; 257/467,469 See application file for complete search history.
(56) References Cited
U.S. PATENT DOCUMENTS
An imager temperature sensor and a current correction apparatus are provided which use dark pixel measurements from an imager chip during operation together with a fabrication process constant as well as a chip dependent constant to calculate chip temperature. The chip temperature may be used to generate a current correction signal. The correction signal is used to tune a current on the imager chip to correct for temperature variations.
25 Claims, 9 Drawing Sheets