Curved surfaces are the preferred shape for image sensors—just think of the human eyeball and the 35 mm photographic plastic ﬁlm used in analog photocamera.
Nevertheless, today's digital image sensor arrays are ﬂat and suffer from vignetting, i.e., image quality decreases from the center to the edge of the detector due to the angle at which the photons hit the outer pixels. Vignetting is typically combatted with a series of optical lenses, but that results in a bulky optical system. Curved and hemispherical detectors would not need such lenses, thereby simplifying the optical lens system ultimately to a simple, one-lens conﬁguration.
Albert van Breemen et all have published a paper on curved digital X-ray detectors in Nature Flexible Electronics. We will also touch on this subject during our webinar on Monitoring and diagnosis using large-area sensors – Part II on 17 September 2020.