Patent ID: 8520104

Claim:
A three-dimensional (3D) image sensor, comprising: a light source emitting light; and a pixel array; wherein the pixel array comprises: a first well and a second well, separated from each other, each being doped into a first type; a first gate and a second gate respectively formed on a surface of the first well and a surface of the second well, each being doped into a second type; and a first layer, doped into the first type, generating photocharges by absorbing reflected light incident on a surface of the 3D image sensor and providing the generated photocharge to the first or second well based on a voltage applied to the first or second gate; wherein a first voltage is applied to the first gate and a second voltage having a phase difference of 180° from the first voltage is applied to the second gate and the first voltage input to the first gate has the same phase as that of the light emitted from the light source; and wherein the first and second gates are configured to transfer the first and second charges, respectively, and wherein a calculation of distance between the 3D image sensor and an object illuminated by the light source is based on a difference between the first and second charges.