Roger W Graham

US Patent:

6885002, Apr 26, 2005

Filed:

Aug 31, 2001

Appl. No.:

09/945518

Inventors:

James A. Finch - Santa Barbara CA, US
Roger W. Graham - Santa Barbara CA, US
Stephen H. Black - Buellton CA, US
Jerry A. Wilson - Goleta CA, US
Richard H. Wyles - Carpinteria CA, US

Assignee:

Raytheon Company - Waltham MA

International Classification:

H01L025/00

US Classification:

250332, 250330

Abstract:

A unit cell () of a readout integrated circuit is constructed and operated so as to temporally align an image obtained in a first spectral band with a an image obtained in a second spectral band. A method operates, during a frame period, to sub-frame average a first signal detected in the first spectral band by a multi-spectral detector (), to sub-frame average a first signal detected in the second spectral band by the multi-spectral detector, and to sub-frame average a second signal detected in the first spectral band by the multi-spectral detector. The method then reads out the sub-frame averaged signals for each spectral band. The sub-frame averaged may be read out simultaneously from the unit cell. When sub-frame averaging the first and second signals in the first spectral band the method performs a plurality of consecutive sub-integrations and stores the result of each sub-integration on a first sub-frame averaging capacitance, and when sub-frame averaging the first signal of the second spectral band the method performs a single integration of the second signal, and stores the result of the integration on a second sub-frame averaging capacitance. The first spectral band may correspond to long wavelength infrared radiation (LWIR), and the second spectral band may correspond to medium wavelength infrared radiation (MWIR).

US Patent:

7095355, Aug 22, 2006

Filed:

May 9, 2005

Appl. No.:

11/125509

Inventors:

Roger W. Graham - Santa Barbara CA, US
John T. Caulfield - Santa Barbara CA, US

Assignee:

Raytheon Company - Waltham MA

International Classification:

H03M 1/12
H03M 1/56
H01L 27/00

US Classification:

341169, 341172, 2502081

Abstract:

An analog to digital converter ADC is adapted for low power for use in an imaging array. The ADC is a digital inverter with feedback to convert an asynchronous ramp voltage to an output count at each crossing of a voltage threshold. A separate circuit generates a voltage ramp that is coupled through a capacitor to a photocurrent from a detector, generating an integrating voltage that is raised at a source follower circuit. The integrating voltage from the source follower circuit is converted to another voltage ramp and inverted at the ADC. A global count from an array of such ADCs is stored in a grey counter. The ADC is sufficiently power-efficient that each unit cell of an array of photo detectors can have its own ADC. Circuit and device-level embodiments are disclosed.

US Patent:

7800672, Sep 21, 2010

Filed:

May 9, 2005

Appl. No.:

11/125510

Inventors:

Roger W. Graham - Santa Barbara CA, US
John T. Caulfield - Santa Barbara CA, US

Assignee:

Raytheon Company - Waltham MA

International Classification:

H04N 5/335
H04N 3/14

US Classification:

348307, 2502081

Abstract:

A circuit includes a compression sub-circuit having an input and an output for dumping excess current, a voltage bucket, and a current source. The voltage bucket, such as a capacitor, and the current source, such as a photodetector, are coupled in parallel to the input of the compression sub-circuit. Preferably, the compression sub-circuit is a single FET having a gate voltage selected to allow current to bleed off or be dumped through the FET as the capacitor approaches being full, and dumps excess photocurrent when the capacitor is full. The capacitor is nearly full when it is at least three quarters full, and is substantially full or approaching being full when it is at least 90% of capacity. In a photodetector embodiment, one plate of the capacitor is coupled to the FET and the opposed second plate is coupled to a ramping voltage circuit.

US Patent:

8415623, Apr 9, 2013

Filed:

Nov 23, 2010

Appl. No.:

12/952282

Inventors:

Roger W. Graham - Santa Barbara CA, US

Assignee:

Raytheon Company - Waltham MA

International Classification:

G01J 5/00

US Classification:

2503381

Abstract:

According to certain embodiments, an apparatus comprises a first readout integrated circuit (ROIC), a second ROIC, and a dual band detector array. The first ROIC comprises first unit cells. The second ROIC is disposed outwardly from the first ROIC and comprises a second unit cells. Electrically conductive vias are disposed through the second ROIC and at least into the first ROIC. The detector array is disposed outwardly from the second ROIC. The detector array is configured to detect high dynamic range infrared light and comprises detector pixels. Each detector pixel is configured to generate a current in response to detecting light and send the current to a via. A via is configured to send the signal to a second unit cell and a first unit cell.