A MOS Image Sensor With a Digital-Microlens

Author

Onozawa, Kazutoshi ; Toshikiyo, Kimiaki ; Yogo, Takanori ; Ishii, Motonori ; Yamanaka, Kazuhiko ; Matsuno, Toshinobu ; Ueda, Daisuke

Author_Institution

Matsushita Electr. Ind. Co., Ltd., Osaka

Volume

55

Issue

4

fYear

2008

fDate

4/1/2008 12:00:00 AM

Firstpage

986

Lastpage

991

Abstract

We have developed a MOS image sensor with digital-microlenses (DMLs), each of which has an effective refractive index realized by variation of the subwavelength separations between the concentric SiO₂ ring walls. The effective refractive index profiles are optimized for the location of each pixel. The light-collection efficiency of the image sensor is twice as high as that of a conventional image sensor because of the enhanced light acceptance in the periphery. A 2.2-mum pitch 3-megapixel MOS image sensor based on the DML technology exhibited excellent uniformity of the light-collection efficiency across the image area, even for light with a very large incident angle, i.e., over 45deg. The DML promises new levels of performance of image sensors.

Keywords

image sensors; microlenses; silicon compounds; MOS image sensors; SiO₂; digital-microlenses; enhanced light acceptance; refractive index; subwavelength structure; Cameras; Cellular phones; Image sensors; Lenses; Lithography; Microoptics; Refractive index; Resins; Security; Sensor arrays; Effective refractive index; image sensor; microlens; sensitivity; subwavelength structure;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/TED.2008.917331

Filename

4469665