US Patent 10075663 Phase detection pixels with high speed readout

Phase detection pixel pairs may include first and second photodiodes covered by a single microlens. To decrease the readout time of the phase detection pixels, each phase detection pixel may have a respective floating diffusion region. Each phase detection pixel may include a transfer gate that can be asserted to transfer charge from the photodiode to the floating diffusion region. During readout, charge from each photodiode in the phase detection pixel pair may be read out in parallel. The phase detection pixel pairs may be implemented in multiple substrates connected by interconnect layers.