An optical modulation device includes following elements. Bus lines are extended in a first direction, wherein each bus line supplies a respective voltage. A first plate includes first lower electrodes extended in a second direction crossing the first direction, wherein a rightmost first lower electrode is connected to a first bus line of the bus lines and a leftmost first lower electrode is connected to a second bus line of the bus lines. A second plate faces the first plate, and includes at least one upper electrode. A liquid crystal layer is positioned between the first plate and the second plate and includes liquid crystal molecules. A first resistor string includes first resistors, wherein each resistor positioned between two adjacent first lower electrodes connects electrically the two adjacent first lower electrodes, causing a voltage drop between the two adjacent first electrodes.