qCMOS Camera C15550-20UP / C15550-20UP01 Instruction manual_Ver.1.3
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10. DESCRIPTION OF CMOS IMAGE SENSOR
10-1 THEORY OF CMOS IMAGE SENSOR
The pixel of a CMOS image sensor is composed of the photodiode and the amplifier that converts the
charge into voltage. Entered light is converted to charge and converted to voltage in the pixel. The voltage
of each pixel is output by switching the switch one by one. (Figure 10-1)
The scientific CMOS image sensor used in this camera has an on-chip CDS (correlated double sampling)
circuit, which plays an important role in achieving low noise. In addition, column amplifiers and A/Ds are
adopted for odd row pixels and even row pixels, respectively. For this reason, 2 line parallel readout is
conducted and both low noise and high speed readout are provided simultaneously.
Figure 10-1 Structure of CMOS image sensor
CDS
CDS
CDS
CDS
CDS
A/D
Digital data out
Photo Diode
Amp
CDS
Digital data out
A/D
CDS
A/D
CDS
A/D
CDS
A/D
CDS
A/D
A/D
A/D
A/D
A/D
CDS
CDS
CDS
A/D
CDS
A/D
CDS
A/D
CDS
A/D
A/D
A/D
