There has been neck to neck competition between CCD and CMOS imaging technologies. CCD and CMOS imagers
were invented in the same era within a span of few years. Yet, CCDs
became dominant because of the superior results from the then available
fabrication technology. CMOS technologies focused on uniformity and
smaller feature sizes, which did not quite happen until 1990s when
lithography advanced enough to be support small feature sizes. It was
after this that CMOS imagers had a comeback and since then both
technologies have fought for market dominance. While CCD sensors are
known to offer best image qualities, CMOS imagers
offer more functions on the chip and attractive features like lesser
power usage making them more popular in mobile phone cameras etc. A
comparison can be drawn between the two on various aspects and a sound
decision be made depending on the requirements of the application.
Factor
|
CCD
|
CMOS
|
Responsivity
|
Moderate
|
Higher
|
Dynamic Range
|
High
|
Moderate
|
Uniformity
|
High
|
Low
|
Speed
|
Moderate
|
Higher
|
Anti blooming
|
High
|
High
|
Signal out of pixel/chip
|
Electron Packet/Voltage
|
Voltage/Bits
|
System/Sensor Complexity
|
High/Low
|
Low/High
|
Noise
|
Low
|
High
|
Markets have seen rapid decline of the CCDs share owing to the growing popularity of CMOS sensors
in cell phones and point and shoot cameras and even industry stalwarts
like Canon and Sony who used CCD products primarily are now shifting to
CMOS imagers. It is expected that more than 95% of the camera market
will switch over to CMOS sensors by 2014. But there still remains and
would remain a predominant segment which will continue to bank on CCD
sensors, the scientific research and the astronomer community, the
biggest example being the Hubble Space Telescope. So, while the light
from the CCDs might be fading from the earth, we’d still need a CCD to
see what’s out there.