Active pixel sensor array with electronic shuttering

• US 20030111674A1
• Filed: 11/26/2002
• Published: 06/19/2003
• Est. Priority Date: 01/28/1994
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Fossum, Eric R.
• Granted Patent: US 6,825,059 B2
• Time in Patent Office: Days
• US Class Current: 257/215
• CPC Class Codes: G11C 19/282 with charge storage in a depletion layer, i.e. charge coupled devices [CCD]
• CPC Class Codes: G11C 19/285 Peripheral circuits, e.g. for writing into the first stage; for reading-out of the last stage
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14623 Optical shielding
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14645 Colour imagers
• CPC Class Codes: H01L 31/02162 for filtering or shielding light, e.g. multicolour filters for photodetectors
• CPC Class Codes: H01L 31/0232 Optical elements or arrangements associated with the device H01L31/0236 takes precedence; for photovoltaic cells H01L31/054; for photovoltaic modules H02S40/20
• CPC Class Codes: H04N 23/10 for generating image signals from different wavelengths
• CPC Class Codes: H04N 25/10 for transforming different wavelengths into image signals
• CPC Class Codes: H04N 25/531 by controlling rolling shutters in CMOS SSIS
• CPC Class Codes: H04N 25/616 involving a correlated sampling function, e.g. correlated double sampling [CDS] or triple sampling
• CPC Class Codes: H04N 25/65 applied to reset noise, e.g. KTC noise related to CMOS structures by techniques other than CDS
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 25/77 Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components
• CPC Class Codes: H04N 25/78 Readout circuits for addressed sensors, e.g. output amplifiers or A/D converters
• CPC Class Codes: H04N 3/155 Control of the image-sensor operation, e.g. image processing within the image-sensor

Abstract

An active pixel cell includes electronic shuttering capability. The cell can be “shuttered” to prevent additional charge accumulation. One mode transfers the current charge to a storage node that is blocked against accumulation of optical radiation. The charge is sampled from a floating node. Since the charge is stored, the node can be sampled at the beginning and the end of every cycle. Another aspect allows charge to spill out of the well whenever the charge amount gets higher than some amount, thereby providing anti blooming.

Claims

1. A method of operating an optical pixel cell device comprising:

forming a substrate with an optical blocking layer located adjacent said substrate which divides said substrate into an optically blocked area and an optically unblocked area;

accumulating charge in said optically unblocked area; and

storing and processing charge in said optically blocked area.