An electronic modulating device is provided. The electronic modulating device includes a substrate, a plurality of first modulating electrodes disposed on the substrate, and a plurality of second modulating electrodes disposed on the substrate. The area of one of the first modulating electrodes is greater than the area of one of the second modulating electrodes. The ratio of the number of first modulating electrodes to the number of second modulating electrodes is in a range from 0.5 to 2.0.