US Patent 9244253 Small form factor high-resolution camera

A camera including a spherically curved photosensor and a lens system. Effective focal length f of the lens system is within about 20% of the radius of curvature of the photosensor. An image is formed by the lens system at a spherically curved image plane that substantially matches the concave surface of the photosensor. The camera is diffraction-limited with small spot size, allowing small pixels to be used in the photosensor. F/number may be 1.8 or less. The spherically curved image plane formed by the lens system at the photosensor follows f*θ image height law. Chief rays of the lens system are substantially normal to the concave surface of the photosensor. Total axial length of the camera may be 2.0 mm or less. The camera may be implemented in a small package size while still capturing sharp, high-resolution images, making the camera suitable for use in small devices.