A Canon patent for teardrop-shaped microlenses for the company’s image sensors was spotted by Image Sensors World. Such a microlens design should cut vignetting and other color aberrations.
The present invention provides a solid state image sensor including a pixel array having a plurality of pixels arranged therein, each of the plurality of pixels including a photoelectric conversion device and a microlens configured to guide incident light to the photoelectric conversion device, the microlens having a lower surface, on an exit side of the incident light, which has a convex shape with respect to the photoelectric conversion device, with a vertex of the convex shape shifting from a center position of the microlens to a central side of the pixel array.
The surface of each microlens 103 which is located on the exit side of incident light, that is, a lower surface 102, will be described. The lower surface 102 of the microlens 103 has an asymmetrical shape with a position nearest to the photoelectric conversion device 104 (a position at which the thickness from a center plane 130 of the microlens 103 is the maximum) shifting from the center position of the microlens 103 to the central side of the pixel array 110A. The lower surface 102 of the microlens 103 has a convex shape with respect to the photoelectric conversion device 104.
Each microlens 103 is formed from a material having a higher refractive index than a material in contact with the lower surface 102 at a position between the microlens 103 and the photoelectric conversion device 104. The microlens 103 is formed from, for example, a color filter material.
[via Image Sensors World