Optical imaging sensor
The MLX90255BC linear sensor array consists of a 128 x 1 array of photodiodes, associated charge amplifier circuitry and a pixel data-hold function that provides simultaneous-integration start and stop times for all pixels. The pixels measure 200µm (H) by 66 µm (W). Operation is simplified by internal control logic that requires only a serial-input (SI) signal and a clock. The sensor consists of 128 photodiodes arranged in a linear array. Light energy falling on a photodiode generates photocurrent, which is integrated by the active integration circuitry associated with that pixel. During the integration period, a sampling capacitor connects to the output of the integrator through an analog switch. The amount of charge accumulated at each pixel is directly proportional to the light intensity and the integration time. The output and reset of the integrators is controlled by a 132-bit shift register and reset logic. An output cycle is initiated by clocking in a logic 1 on SI. This causes all 132 sampling capacitors to be disconnected from their respective integrators and starts an integrator reset period.