New Panasonic CMOS Image Sensor
A May 15th press release article, on Panasonic's website, describes a new image sensor technology that looks pretty promising.
Most of the time when I read a press release on a companies website, I take it with a bag of rock salt because a grain just won't do it. However, I believe this technology offers some genuine benefits.
Existing sensors use dyed polymer (plastic) filters to filter red, green, or blue light onto appropriate sensors and polymer (plastic) micro-lenses to focus light onto the photosensitive portion of the pixel. Such a thin layer of dye is readily bleached by UV light. Even with UV filters enough UV gets through to damage the dye filters over time causing digital cameras color rendition to degrade with time.
With existing CMOS sensors, the actual light sensitive region only occupies about 30% of the chip surface so to improve sensitivity they use micro lenses over the individual pixels to gather light from a larger area and focus it on the pixel. This is not without it's own problems because the micro lenses are less effective for light coming at them from an angle rather than straight on and thus pixels away fro the center of the image receive less light assuming the micro lenses are identical.
In addition to the limitations of this technology in terms of durability and image quality, the use of polymer on silicon is expensive. Everything has to be just so in order for the micro lenses to properly overlay the individual pixel sensors uniformly.
Panasonic has eliminated the need for polymer on silicon by incorporating sub-wavelength features on the chip die allowing for the construction of Fresnel like micro lenses and light filters directly out of silicon. Since the filters rely on physical structures, they are not susceptible to UV induced fading. Since the lenses are made using standard photo lithography techniques, they can be can be customized for their position on the sensor surface and compensate for the angle of incident light.
Since the new CMOS sensor should be cheaper to manufacturer it might just find it's way into some of the lower end cameras presently utilizing CCD image devices.
Everything I've read says that CCD's have higher sensitivity and lower noise than CMOS devices, but my own experience has been exactly the opposite. This might have to do with the fact that I like to do a lot of night photography and utilize long exposures so much of my utilization is atypical.
Most of the time when I read a press release on a companies website, I take it with a bag of rock salt because a grain just won't do it. However, I believe this technology offers some genuine benefits.
Existing sensors use dyed polymer (plastic) filters to filter red, green, or blue light onto appropriate sensors and polymer (plastic) micro-lenses to focus light onto the photosensitive portion of the pixel. Such a thin layer of dye is readily bleached by UV light. Even with UV filters enough UV gets through to damage the dye filters over time causing digital cameras color rendition to degrade with time.
With existing CMOS sensors, the actual light sensitive region only occupies about 30% of the chip surface so to improve sensitivity they use micro lenses over the individual pixels to gather light from a larger area and focus it on the pixel. This is not without it's own problems because the micro lenses are less effective for light coming at them from an angle rather than straight on and thus pixels away fro the center of the image receive less light assuming the micro lenses are identical.
In addition to the limitations of this technology in terms of durability and image quality, the use of polymer on silicon is expensive. Everything has to be just so in order for the micro lenses to properly overlay the individual pixel sensors uniformly.
Panasonic has eliminated the need for polymer on silicon by incorporating sub-wavelength features on the chip die allowing for the construction of Fresnel like micro lenses and light filters directly out of silicon. Since the filters rely on physical structures, they are not susceptible to UV induced fading. Since the lenses are made using standard photo lithography techniques, they can be can be customized for their position on the sensor surface and compensate for the angle of incident light.
Since the new CMOS sensor should be cheaper to manufacturer it might just find it's way into some of the lower end cameras presently utilizing CCD image devices.
Everything I've read says that CCD's have higher sensitivity and lower noise than CMOS devices, but my own experience has been exactly the opposite. This might have to do with the fact that I like to do a lot of night photography and utilize long exposures so much of my utilization is atypical.
posted by Nanook at 8:04 PM
0 Comments:
Post a Comment
Links to this post:
Create a Link
<< Home