Dutch start-up Eyeo has secured €15 million in seed funding to develop new picture sensor expertise with the aim of tripling a sensor’s gentle sensitivity. The brand new color-splitting photonics innovation is alleged to “unlocks image high quality, shade accuracy, decision, and value effectivity, which was by no means earlier than potential”.
For many years shade picture sensors have nearly all the time used a Bayer shade filter array, filtering incoming gentle into purple, inexperienced and blue wavelengths that are then captured by corresponding photosites on the floor of the picture sensor. Historically a sensor has been divided into 50% inexperienced, 25% purple, and 25% blue photosites (RGGB), although variations of this have been launched over time.
Whereas Bayer filter expertise is important to allow a picture sensor to seize shade, it is not with out drawbacks. The first compromise being that every sensor photosite solely ever receives a fraction of the sunshine that enters the colour filter layer, as at the least 50% will probably be blocked on account of it being the mistaken shade wavelength. This then restricts a sensor’s dynamic vary and makes it extra vulnerable to producing picture noise in low gentle circumstances, whereas the demosaicing algorithms wanted to interpolate the uncooked purple, inexperienced and blue shade information right into a full shade spectrum will inevitably blur the ultimate digital picture to some extent, limiting the quantity of nice element that may be resolved.
These limitations have lengthy been identified, with makes an attempt already made to handle them. Probably the most recognizable of those is probably going the Foveon X3 sensor, now synonymous with Sigma, which makes use of a essentially completely different sensor development that does away with the Bayer filter to drastically enhance gentle transmission. Eyeo’s strategy, although sharing the identical aim as Foveon X3, makes use of conventional CMOS sensor development, solely altering the best way wherein gentle is directed to the sensor photosites.
Fairly than filtering incoming gentle (and due to this fact blocking a big share of it), Eyeo’s expertise guides gentle to photosites through vertical waveguides, or to make use of their full identify: ‘wafer-level-integrated vertical-waveguide sub-diffraction-limited shade splitters’. The system implements stacked vertical waveguides to seize full-spectrum white gentle, guiding every shade wavelength to a distinct photosite. The guides are tuned to direct gentle based mostly on the typical sensitivity of human eye shade sensing cones, although they can be tuned to different spectral ranges, together with UV, relying on the sensor’s utility. By solely altering the color-separating layer of the picture sensor, Eyeo claims the remainder of the CMOS sensor and its electronics can stay unchanged. The corporate additionally states that it has already fashioned partnerships with main picture sensor foundries, with this newest seed funding getting used to develop a product which may very well be mass-manufactured.
Ditching the traditional shade filter array has the potential to drastically enhance gentle transmission, leading to noticeably improved picture high quality with out rising a sensor’s bodily measurement. But it surely additionally means picture sensors can conceivably be shrunk smaller whereas nonetheless sustaining acceptable output high quality. That is nice information for space-sensitive units like smartphones and safety cameras. The brand new tech additionally permits sensor sizes to be lowered with out decreasing megapixel counts. Using a Bayer filter retains pixel sizes to a minimal of 0.5-microns, as going smaller may end up in picture degradation on account of optical diffraction. Eradicating the colour filter and changing it with vertical waveguides has the potential to permit sensor producers to cut back the scale of particular person pixels under this present restrict. As for once we would possibly see this new expertise developed right into a client product, Eyeo states that “the primary analysis kits are anticipated to be obtainable for chosen clients inside the subsequent two years.” Watch this house…