Digital Camera Combined with Optical Sensors

Digital Camera is now growing in demand. Why? How could we take a piture with the

device having no film in it? It`s because of the CCD(charge-coupled device) which

serves as a film in the camera. CCD is a combination of numerous optical sensors. As

for Digital Camera, the definition of pictures depend on the number of pixels.

Cameras with four to five million pixels are currently considered the best quality,

which cost around 1 million won. It makes almost no difference in terms of definition

quality from that of Analog Camera, when it is printed out in A4 size.

CCD looks like a square-shaped dish that has numerous optical sensors whose number

is the same as the number of pixels(ex) 4 million pixels have 4 million optical

sensors on CCD).

Each optical sensor has color filters attached to it, which feature the three primary

colors, red, green and blue. Red filter get through only the color of red so that it

can be sent to each optical sensor. The intensity of radiation is converted to

electrical signals through the optical sensors.

Then, the information about the electrical charge is recorded in CCD, which make

picture files. CCD is used for a lot of devices including digital camcoders,

surveillance cameras. CCD can also be used to recognize the finger prints of iris of

people in screening process.

Digital camcoder has lower quality definition with about two to five hundred thousand

of pixels, lower than other cameras. Cameras carried in computers and mobile phones

have CIS using CMOS (complementary metal-oxide semiconductor) technology, instead

of CCD. Using same optical sensors, but CIS has an edge in simple making process and

resonable prices.

But it has relatively lower quality definition. Now many companies

around the world are working on improving the definition of CIS. So it is expected

that we will be able to enjoy face-to-face mobile phone calls with high quality

definition within a couple of years.

dream@donga.com