Method and apparatus for performing autofocusing using summed signals

An image sensor, comprising:

• a pixel array including a first unit pixel and a second unit pixel, wherein each of the first to second unit pixels includes four photodiodes;
• a first microlens on the four photodiodes in the first unit pixel;
• a second microlens on the four photodiodes in the second unit pixel;
• a readout circuit configured to:
• generate a first added signal by adding a first signal obtained from a first photodiode in the first unit pixel and a second signal obtained from a second photodiode in the second unit pixel, and
• perform an autofocusing operation based on the first added signal;
• a first green color filter on the four photodiodes in the first unit pixel;
• and
• a second green color filter on the four photodiodes in the second unit pixel,
• wherein the first unit pixel is disposed on a first row and the second unit pixel is disposed on a second row different from the first row.

An image sensor, comprising:

• a pixel array including a first sub-pixel group having a first unit pixel and a second sub-pixel group having a second unit pixel, wherein each of the first and second sub-pixel groups includes sixteen photodiodes;
• a first-four microlens on the sixteen photodiodes in the first sub-pixel group;
• a second-four microlens on the sixteen photodiodes in the second sub-pixel group;
• a first green color filter on the sixteen photodiodes in the first sub-pixel group;
• a second green color filter on the sixteen photodiodes in the second sub-pixel group;
• a readout circuit configured to:
• generate a first added signal by adding a first signal obtained from a first photodiode in the first unit pixel and a second signal obtained from a second photodiode in the second unit pixel, and
• perform an autofocusing operation based on the first added signal,
• wherein each of the first and second unit pixels includes four photodiodes, and
• wherein the first photodiode in the first unit pixel is disposed on a first row and the second photodiode in the second unit pixel is disposed on a second row different from the first row.