Curved sensors for compact and high-performance imaging systems (Conference Presentation)

Curved sensors are a disruptive technology which allow improvement of the image quality and substantial simplification of optical designs. Both bring to the reduction of the volume and mass of the instruments, while improving their performance. The field of curvature is an optical aberration, present in every single optical system, describing the fact that the light going through optics produces an image on a portion of a sphere. The impact of this aberration is seen mostly on the edges of an image by the presence of vignetting and distortion. Current solutions are applied to correct the images, but they imply a growing complexity of the instruments and the increase of their volume. Curved detectors correct this optical aberration directly at the focal surface. Our recent research has demonstrated that curved detectors allow to remove many lenses and release constraints in optical systems, simultaneously making them more compact without performance impairments. The CNRS-LAM has developed a nondestructive, high quality curving process. A full electro-optical characterization performed at LAM on prototypes demonstrates that there is no significant difference among curved and flat sensors. The study and achievement of the association of a wide-angle lens with a curved sensor have proven that it is possible to reduce by a factor of two the number of lenses in the optical system. Moreover, a significant improvement of the sharpness can be noticed, just like the fact that there is no more distortion or vignetting, all until the edges of the image. Curved sensors bring significant improvement of the image quality in trans-disciplinary applications. The team is currently developing new optical concept including a curved focal surface for projects going from bio medical application to space imaging. In this talk I will present our work and results in the frame of freeform CMOS development, optical concept for a wide field imager for an ESA Earth’s aurora monitoring mission and discuss the impact of curved sensors on imaging systems.