Beam deflector, holographic display device having the same, and method of driving the beam deflector

A holographic display device comprising:

• a light source;
• a beam deflector configured to deflect a beam received from the light source;
• and
• a spatial light modulator configured to diffract the beam deflected by the beam deflector to form a hologram image,
• wherein the beam deflector comprises:
• a first substrate;
• a first electrode layer comprising a plurality of first electrodes disposed on the first substrate;
• a second substrate facing the first substrate;
• a second electrode layer comprising a plurality of second electrodes disposed on the second substrate, the plurality of second electrodes being arranged in a one-to-one manner with respect to the plurality of first electrodes;
• a liquid crystal layer between the first substrate and the second substrate;
• and
• a controller configured to cause active prisms to be formed in the liquid crystal layer by adjusting voltages between the plurality of first electrodes and the plurality of second electrodes and to cause a floating zone to be formed between adjacent active prisms by turning off a voltage of at least one of the plurality of first electrodes and plurality of the second electrodes between the adjacent active prisms,
• wherein each of the plurality of first electrodes is configured to be driven independently and each of the plurality of second electrodes is configured to be driven independently,
• wherein a first voltage is independently applied to each of the plurality of first electrodes and a second voltage is independently applied to each of the plurality of second electrodes,
• wherein the floating zone is formed by independently turning off a voltage a first second electrode, among the plurality of second electrodes, and
• wherein an active prism is formed by independently applying a reference voltage to one or more second second electrode, among the plurality of second electrodes other than the first second electrode.