Patent attributes
The present invention concerns a method for operating a CMOS image sensor including a matrix of pixels arranged in a plurality of lines and columns. Each of the pixels include a photosensor element that accumulates charge carriers in proportion to the illumination. A storage device is able to be coupled to the photosensor element at a determined instant in order to generate a sampled signal, which is representative of the charge carriers accumulated by the photosensor. The storage device is intended to assure storage for the purpose of reading the sampling signal. According to the present invention, when the sampled signal which is stored across the storage means is read, the photosensor element is held at a voltage such that any charge carrier generated by the latter is drained and thus does not disturb the sampled signal stored on the storage device. The problem of diffusion of charge carriers typically encountered with such sensors when they are operated in accordance with conventional techniques is thus answered. This method allows use of such a sensor for applications where the exposure time of an image is a determining factor because it is very short.
