An optical system using a single electron trapping (ET) device with areaencoding of input fuzzy variables and negations is proposed to perform fuzzy logic operations in paralle. In this scheme, each encoding cell is only composed of one encoding cell so that the resultant pattern is still the image in which there is no space between any two pixel rows. Baed on the storage and erasure characteristics of the ET device, all of the fuzzy logical functions of two images can be implemented in parallel and spatial invariant by programming the illumination form of data arrays. No thresholding device, lens array and decoding mask is needed, therefore, this system exhibits high operation speed and large information throughout. The system can be compact. The experimental results are also given.