CMOS sensor for sun tracking

Hongyi Wang, Tao Luo, Hongjiang Song, Jennifer Blain Christen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations


We present an optical localization chip capable of detecting the direction of incident light. The chip requires no offchip optical or mechanical components or post-processing (e.g. baffles, slits, mirrors, etc.). The chip was fabricated in a standard 0.5 μm CMOS (complementary metal oxide semiconductor) process. Our approach employs 100 light sensing cells, each having two detectors separated by a metal 'wall'. The 'wall' was created by stacking all metal layers, contacts and vias available in the process. This metal stack 'wall' is used to create on-chip shadowing to facilitate detection. Each optical detection element produces a differential output with the normalized difference between the currents dependent upon the angle of the incident light. The width of the photodiodes is limited by the height of the metal wall to only a few micrometers. To achieve a good sensitivity, 100 cells are placed in parallel. Test results show good sensitivity to the direction and intensity of the incident light with accuracy of 1.9 degrees over a 100 degree range and 1.1 degrees over a 50 degree range.

Original languageEnglish (US)
Title of host publicationIEEE SENSORS 2013 - Proceedings
PublisherIEEE Computer Society
ISBN (Print)9781467346405
StatePublished - 2013
Event12th IEEE SENSORS 2013 Conference - Baltimore, MD, United States
Duration: Nov 4 2013Nov 6 2013

Publication series

NameProceedings of IEEE Sensors


Other12th IEEE SENSORS 2013 Conference
Country/TerritoryUnited States
CityBaltimore, MD

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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