An optical node device, comprising:
- an input and output unit having an input port on which incident light is incident and an output port from which output light according to each wavelength included in the incident light is output;
- a wavelength disperser configured to spatially disperse light of each wavelength included in the incident light according to the wavelength and output the output light toward the input and output unit;
- an optical coupler configured to condense the light of each wavelength dispersed by the wavelength disperser onto a two-dimensional plane for each wavelength and output reflected light of each wavelength to the wavelength disperser;
- a spatial light modulator that is arranged at a position of the two-dimensional plane, has multiple pixels, and configured to reflect, by representing gradation by the multiple pixels, the light of each wavelength condensed by the optical coupler in directions for each wavelength determined by routing;
- a spatial light modulator drive unit configured to drive the multiple pixels of the spatial light modulator;
- and
- a common electrode which is divided into a first common electrode of a first portion on which light is incident and a second common electrode of a second portion on which light is not incident, wherein
- the gradation is formed by inputting normal gradation data in one subframe period of multiple subframe periods which are obtained by dividing one frame period and inverted gradation data in another subframe period of the multiple subframe periods into each of the multiple pixels by the spatial light modulator drive unit,
- each of the multiple pixels comprises:
- a first switching circuit configured to sample the normal gradation data or the inverted gradation data from a data line;
- a first signal holding circuit configured to hold the normal gradation data or the inverted gradation data sampled by the first switching circuit;
- a second switching circuit configured to sample, at a common timing to all of the multiple pixels, the normal gradation data or the inverted gradation data held in the first signal holding circuit;
- and
- a second signal holding circuit configured to hold, for one subframe period, the normal gradation data or the inverted gradation data sampled by the second switching circuit and apply the normal gradation data or the inverted gradation data to a reflective electrode of a liquid crystal display element, and
- the spatial light modulator drive unit is further configured to:
- in the first portion, apply alternating current voltage having a positive polarity and a negative polarity to a liquid crystal of the liquid crystal display element by inverting a voltage in the first common electrode of the liquid crystal display element at the common timing;
- and
- supply a voltage having an amplitude different from an amplitude between the normal gradation data and the inverted gradation data to the first common electrode, and
- in the second portion, voltages of the reflective electrode and the second common electrode are inverted every several subframes of a predetermined number.