We use microlenses as seen in the diagram to refocus light so that it hits the photosensitive portion of the pixel. Without the microlens, light rays arriving at the edge of the color filter and passing straight through would hit the circuitry/non-photosensitive portion of the pixel and not contribute to the integration of incoming light.
We use microlenses as seen in the diagram to refocus light so that it hits the photosensitive portion of the pixel. Without the microlens, light rays arriving at the edge of the color filter and passing straight through would hit the circuitry/non-photosensitive portion of the pixel and not contribute to the integration of incoming light.