Sensor Technology - Vivotek Supreme IP8151 White Paper

processing for higher sensitivity by increasing the amount of light
captured and reduce noise when analog-digital (A/D) conversion, thereby
improving the low light performance of a megapixel IP camera. Supreme
Night Visibility is a key feature of VIVOTEK's latest product offerings,
allowing for low light visibility in color equal or better to that of traditional
analog or CCD cameras. First introduced in the IP8330, and with
continued refinement in the IP8151, this feature is key for users looking
for exceptional low light visibility.
2.

Sensor Technology

The sensor technology used in the IP8151 is a groundbreaking
technology developed by SONY for the Exmor sensor, featuring the
column-parallel A/D conversion technique that meets or surpasses the
performance of CCD sensors while retaining the benefits of CMOS. This
new generation of CMOS sensors combines high sensitivity with low
noise, eliminating the traditional drawbacks of megapixel CMOS sensors.
As shown in Figure2, a pixel on a CMOS sensor consists of an on-chip
micro-lens, color filter, and inner lens to collect light, followed by the
wiring layer and photodiode. When the light passes through the micro
lens, color filter, and inner lens, it reaches the photodiode for
photon-to-digital conversion. Between the inner lens and the photodiode
is the wiring layer. If the wiring layer is too thick, it inhibits or obstructs
photon gathering, and thus reduces the light sensitivity of sensor. On the
other hand, by using copper (Cu) wiring to reduce the thickness of the
wiring layer, it allows the light to be collected effectively. As a result, the
camera provides color images with excellent sensitivity and visibility,
even in nighttime conditions.
Micro lens
Color filter
Inner lens
Al wiring
Light receiving surface
Conventional Structure
Fig. 2 Cross-section of a pixel on a CMOS sensor.
Photodiode
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Structure with Cu Wiring
Cu wiring
For Internal Use Only.