A light modulation device comprising a first transparent electrode layer, a photoconductive layer, a conductive electrode, a light modulation layer, and a second transparent electrode layer formed together in the preceding order, and characterized by the light modulation characteristic of the light modulation layer being a non-linear saturation function of an applied electrical field, and the conductive electrode comprising plural electrode patterns. The light modulation layer modulates the read light when the input light exceeds a specific threshold value wherein by forming the electrode pattern of the conductive electrode in the shape of the pattern to be extracted, the features of the input image corresponding to that shape can be quickly extracted.
Neural network device and image recognition method employing photoconductive liquid crystal device with patterned electrode