While the idea of a curved CMOS sensor is not new, all companies to this point have only developed them as an in-house proposal project and not as a finished, commercially-ready finished product. That has changed thanks to startup, Curve-One.
The first public studies of a curved sensor date back to the early 2000s, but this is the first time that curved sensors are being made available commercially with the intent to mass-produce them. Curve-One, a startup supported by the European Commission through the European Research Council programs, has made its version available after years of research and development.
If you’re wondering why a curved sensor is something that would be desirable, Curve explains:
“The imaging of extended scenes (wide field), has always been a challenge as optical systems naturally curve the focal surface,” Curve writes. “The bending of photographic plates has been used routinely in many fields, even astronomy with the use of Schmidt telescopes which naturally have a convex focal surface.”
“The advent of flat electronic sensors has been a revolution, forcing optical designers to introduce additional optics to fit the flatness of these sensors’ surface,” the company continues. “The classical problem of the planisphere appeared then: a huge distortion is created by the imaging system on the edge of the field. Additional complexity came along with the distortion: field flatteners increase the volume and mass of systems, and chromatic aberrations appear. Also, the imaging response is not uniform across the field.”
In summary, lens manufactures go to great lengths to combat the issues that arise from using a flat sensor, namely introducing field-flattening elements that make lens designs larger and more complex. A curved sensor emulates how the human eye works and would theoretically make lens designs much simpler by removing the need for aspherical elements.
As a second source on the viability of this type of sensor, in 2014, Sony showed a curved full-frame sensor at the VLSI symposium in Hawaii and explained how the technology would allow for simpler lenses and better overall images thanks to greater sensitivity and therefore higher image quality.
Curve’s sensor is a 12 megapixel model with a curvature radius of 150mm with a 5-micron regularity over the surface. The company is targetting mass production with the support of the European Commission as well as the European Space Agency.