Fill factor (image sensor)
The fill factor of a digital image sensor array is the geometric ratio of a pixel's light sensitive area to its total area. For pixels without microlenses, the basic fill factor is the ratio of the responsive photodiode collecting area to the pixel area.[1] Microlenses may be added to gain an effective fill factor closer to 100%, where each lens acts as a condenser to refract light rays into the photodiode that would otherwise miss.[2]
The imperfect transmission of microlenses, such as from surface reflection, limits the effective fill factor to less than 100%.
The final efficiency is limited by the quantum efficiency of the photodiodes, so a 100% effective fill factor does not imply that all photons are detected.
Another design factor that reduces the fill factor is the addition of memory for each each pixel, which is needed to achieve a global shutter function on CMOS sensors.[3]
Photographic film also involves an analog fill factor, where gaps and edge effects of the film grain particles do not respond over all of the surface.
References
- ^ Sebastiano Battiato; Arcangelo Ranieri Bruna; Giuseppe Messina; Giovanni Puglisi, eds. (2010). Image Processing for Embedded Devices: From CFA Data to Image/video Coding. Bentham Science Publishers. p. 12. ISBN 9781608051700.
- ^ Sebastiano Battiato; Arcangelo Ranieri Bruna; Giuseppe Messina; Giovanni Puglisi, eds. (2010). Image Processing for Embedded Devices: From CFA Data to Image/video Coding. Bentham Science Publishers. p. 29. ISBN 9781608051700.
- ^ "Sensors: Global shutter - Personal View Talks". www.personal-view.com. Retrieved 2017-07-29.
- ^ "Sensors: Global shutter - Personal View Talks". www.personal-view.com. Retrieved 2017-07-29.
 | This technology-related article is a stub. You can help Wikipedia by expanding it. |