Symagery Microsystems Inc.

Harusaki Technologies, LLC

Psion Teklogix Systems Inc.

John Scott-Thomas

George Chamberlain

Paul Hua

Alex Roustaei

Tom Little

Ron McDonald

Paul Vulpoiu

The invention is directed to an imaging device and a method of operating the imaging device, which will reduce banding in the image caused by parasitic capacitance. The imaging device comprises an array of pixels arranged in rows and columns and column signal lines adapted to be selectively coupled to the rows of pixels at predetermined times. Each pixel element has a photodetector coupled to a reset switch for receiving a reset signal to reset the photodetector. The imaging device further includes a precharge circuit adapted to place a voltage on the column signal lines. The method of operating the imaging device includes the steps of applying a precharge voltage to the signal lines, resetting the photodetectors in a row, integrating the photodetector voltage as light impinges on the reset photodetectors, coupling the integrated photodetectors to the signal lines, and sampling the integrated voltage coupled to each of the signal lines. When the double sampling technique is used, the steps further include resetting the photodetectors and sampling the photodetector reset voltages on the signal lines. The precharge voltage is applied to signal lines during the integration period of the photodetectors and is disconnected from a signal line during sampling.

Imaging device with pre-charged signal line

Many electrical sensing devices include an array of transducer elements for converting external stimuli to electrical indications. Novel technologies to realize improvements in low power consumption, low noise, and analog output path which occupies minimal die area while maintaining certain data rates are disclosed. A two stage pipeline architecture of the invention in the analog output path maintains fast pixel rates with minimal ADC (analog digital converter) arrangement. A novel power supply and the use of differential amplifiers in connection with a black signal level as a reference voltage are also described.

Electrical sensing apparatus and method utilizing an array of transducer elements

Imaging device

A method and apparatus for testing an image sensor array such as a C-MOS imager which has sensing circuits arranged in rows and columns and wherein the sensing circuits include photosensitive devices is described. A reset voltage is applied to the photosensitive device in each of the sensor circuits such that at least adjacent circuits are reset to different voltage levels. The voltage on each photosensitive device is detected and compared to an expected level to determine if and where any faults may exist in the sensing circuits or lines in the array. A different reset voltage may be applied to each of the sensor circuits, however in one embodiment, a supply with only two voltage levels may be used. One voltage level is applied to every second column to provide a supply voltage to the photosensitive devices and to every second row to generate a reset enable signal for the photosensitive devices. The second voltage level is applied to the remaining columns and rows resulting in different reset voltage levels on adjacent sensing circuits.

Method and apparatus for testing image sensing circuit arrays

This invention is directed to a method and apparatus for determining the level of ambient light impinging on a selected number of pixels in an imaging array where each pixel includes a photodiode. The ambient light may be determined by resetting the pixels in the array and by detecting current flow through the photodiodes in a selected number of the pixels as they are being reset. Alternately, the ambient light may be determined by resetting a selected number of the pixels in the array and by detecting current flow through the photodiodes in the selected number of the pixels as they are being reset. The photodiodes are reset by applying a reverse bias voltage across them and the current flow is detected by measuring the current flow through a resistance in parallel to the selected photodiodes. The selected number of pixels may be divided into one or more groups each having at least one pixel, and the pixels in each group may be arranged in specific patterns within the array. The array may be laid out in rows and columns, and the groups may be located in predetermined rows or columns. When only a selected number of pixels are reset and these pixels are divided into groups, the groups may be sequentially reset to permit differentiation between the groups.

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Ottawa, Canada

John Scott-Thomas