Curve Image Sensor Developed By French Start-up Curve-One

Recently, a French start-up company has developed a curved image sensor. What issues do standard image sensors suffer from, what has the start-up developed, and why is it an important step?

Why are flat sensors troublesome?

Image technology in electronics has come a long way from the development of individual pixel sensors to full-fledge, full-frame sensors that contain hundreds of megapixels. Of course, anyone in the photography field knows that megapixels account for very little in the end quality of an image as the most important part of a camera setup is generally the lens itself.

In order to focus light onto a sensor, a curved piece of glass is used (shaped like a magnifying glass). While this method allows for the capturing of focused images, it is not without many faults. The first is that the use of standard glass in a lens can introduce all kinds of optical artefacts such as distortion on the edge of the lens and light refraction whereby light is split into its individual frequencies (like a prism). The second is that the image from a lens is curved in nature, but the sensor receiving the image is flat. Therefore, parts of the sensor will not receive correctly focused light, and therefore will result in a loss of sharpness.

Modern cameras can solve the issue with sharpness by introducing multiple lenses that can redirect light so that it falls onto the sensor better, but this results in more glass between the object being imaged, and the sensor. Therefore, the overall brightness of the image is reduced which requires amplification from the sensor, and the result of this is the noise introduced into the image.

French start-up develops a curved image sensor

A new French start-up company, called Curve-One, a startup supported by the European Commission have developed the world’s first curved CMOS image sensor that, if commercialised, will create a technological revolution in camera technology. While curved sensors have been patented by multiple companies including Sony, none have produced a device that could be commercialised.

Curve-One, however, has created a CMOS-based sensor that is not only curved but utilises readily available technology. According to Curve-One, off the shelf sensors are used which are then curved meaning that the 12MP sensor by Curve-One is ready for commercialisation. The demonstration image taken with the sensor by Curve-One demonstrates how well the sensor is able to retain sharpness through-out its sensor without the need for special lenses.

The lens is inspired by the human eye which utilises a curved retina. While the use of a pupil can provide image focusing (the same effect found in pin-hole cameras), it is the lens in the eye that provides the focus onto the retina, and the eye only needs one lens to focus light onto the retina.

How will the new sensor design help future photography?

While the new sensor is unlikely to enter consumer camera devices, for the time being, it will most likely become available for research, industry, aerospace, and military. The ability to reduce the total number of lenses in a system allows for reduced weight (glass is heavy), as well as a reduced size.

A camera with a lower weight and size can allow for a more compact design, and the reduction in the number of lenses also improves the brightness of the final image. Therefore, cameras designed to operate in low-light conditions will greatly benefit from the new technology, and if used in the consumer market could result in devices with low-light cameras. The use of fewer lenses also allows for a larger theoretical aperture, which further improves the performance of the camera in low-light conditions.

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