Thomson-csf Semiconducteurs Specifiques

Thomson Composants Militaires Et Spatiaux

Pierre Dautriche

Yvon Cazaux

Jean-Louis Coutures

Gilles Boucharlat

Disclosed is a photodetector comprising at least one photosensitive diode and at least one read circuit enabling the charges generated by photoelectric effect in said diode to be converted into a voltage information element sampled by a switch, wherein said photosensitive diode has a first terminal connected to the gate and to the drain of a first transistor and a second terminal connected to the source of said first transistor and to the ground of said photodetector, wherein a second transistor with dimensions proportional to those of said first transistor is mounted as a current mirror with respect to said first transistor and wherein an integration capacitor is connected to the drain of said second transistor so as to collect said voltage information element at its terminals.

Circuit to eliminate the dark current of a photodetector

A method of detecting electromagnetic radiation imparted onto a matrix of photosensitive photomos networks in which pixels of each photomos network are simultaneously exposed to electromagnetic radiation source for a predetermined period of time. Thereafter, transfer signals are applied to each photomos pixel and accumulated charges corresponding to the strength of the radiation imparted onto the pixels are transferred in a columnwise fashion to the end of each column of the photomos networks. The charges are summed at the end of the columns and placed in a reading register. The charges in the reading register of each photomos network are summed and a signal is output corresponding to the strength of the electromagnetic radiation imparted onto the photomos network.

Large-sized pixel image detector

Method of detecting electromagneto radiation in a large-sized pixel

A thermal image detector and, more particularly, linear or matrix pyroelectric detectors. These detectors work differentially in successive phases of illumination and masking via a shutter that is synchronized with signal processing circuits. The detector generates differential measurement signals representing variations of pyroelectric signals recorded during a cycle comprising a masking phase and an illumination phase. To eliminate fixed pattern noise, it is proposed to make the measurements by difference between two successive cycles of masking and illumination, the order of the illumination/masking cycles being reversed between the two cycles but the measurements being made identically in both cycles. A memory records the signals during a cycle. A subtractor subtracts the signal of the current cycle from the signal recorded in the previous cycle.

Thermal image detector provided with means to eliminate fixed pattern

The disclosure relates to thermal image detectors and, more particularly, to linear or matrix type pyroelectic detectors. These detectors work differentially, in successive phases of masking and illumination, by use of a shutter that is synchronized with the signal processing circuits. The detected signals are shed in the form of charge packets into a shift register (RD). To reduce the noises that are proportional to the duration of the illumination or masking phases, the shutter is made to work at higher speed and several successive illumination/masking cycles are carried out by making the shift register go backward between two cycles. The shift register is emptied to give an image signal only after two or more cycles.

Thermal image detector with fast shutter period, and method of operation

Infrared detectors whose detecting part consists of a layer of pyroelectric material deposited on a semiconductive substrate are disclosed. The object is to facilitate the polarization of the layer of pyroelectric material after it is deposited on the semiconductive substrate. The detector of the invention includes a semiconductive substrate (15) carrying a layer of pyroelectric material (11) in which are defined zones, each corresponding to a pixel (P1 to P9). Each pyroelectric zone is defined by an electrode known as lower electrode (EI 1 to EI 9), in contact with a face of pyroelectric layer (11) oriented toward substrate (15). According to a characteristic of the invention, a diode known as polarization diode (DP) is formed in substrate (15) for each pixel (P1 to P9). The polarization diode is connected to lower electrode (EI 1 to EI 9) to make possible the passage of a current between substrate (15) and the lower electrode.

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Claix, France

Pierre Dautriche