CCD-abbreviation of English Charge Coupled Device, Chinese name is "Charge Coupled Device".
Cmos-abbreviation of English complementary metal-oxide semiconductor, Chinese name is "complementary metal-oxide semiconductor".
2. 1)CCD is the mainstream imaging device at present, which is mainly divided into:
(1)R-G-B primary CCD: This is the most widely used CCD in digital cameras.
(2)C-Y-G-M complementary color CCD: Some Nikon digital cameras used this complementary color CCD earlier.
(3)R-G-B-E four-color CCD: This is the latest CCD released by Sony, which has one more E (Emerald) color than RGB primary CCD.
2) Super CCD: It is a patented technology of Fuji Company in Japan. Its Chinese name is Super CCD, which evolved from CCD and has now developed to the fourth generation.
3)CMOS: As an imaging device of digital camera, it has not appeared for a long time, but it has developed very rapidly and is likely to compete with CCD. There is no essential difference between the pixel arrangement in its basic structure and the R-G-B primary color CCD. Canon is the main supporter of the CMO camp.
4)Foveon X3: Its essence is also CMOS, but its structure is very different from that of CMOS. At present, the highest pixel reaches 5 million.
3. How does a digital camera image?
A) light is projected onto the surface layer of a photosensitive element through a lens;
B) the light is decomposed into different colors by the surface filter of the photosensitive element;
C) The colored light is induced by the photosensitive unit corresponding to each filter to generate analog current signals with different intensities, and then these signals are collected by the circuit of the photosensitive element;
D) Analog signals are converted into digital signals by digital-to-analog converters, and then these signals are processed by DSP and restored into digital images;
E) transmitting the digital image to a memory card for storage.
4. What are the characteristics of 4.CCD?
The CCD technology is mature and the imaging quality is good. After all, it is the most widely used imaging element now, but it also has shortcomings:
1) consumes a lot of power. Early digital cameras were known as "electric tigers", and one of the main reasons came from CCD. Although the use of low-energy components such as low-temperature polysilicon display screen reduces the power consumption of the camera to a certain extent, CCD is still a big power consumer of digital cameras-CCD keeps working at any time after the digital camera is turned on, which consumes a lot of electricity unnecessarily.
2) The process is complicated and the cost is high. The complex structure of CCD determines the complexity of its manufacturing process, so so far, only a few electronic giants can produce CCD.
3) pixel promotion is difficult. The first two shortcomings of CCD also directly lead to this shortcoming. There are only two ways to improve CCD pixels: one is to increase the CCD area by keeping the unit area of photosensitive elements unchanged, and integrate more photosensitive elements on a large CCD. However, this method will lead to low yield of CCD, high manufacturing cost and high power consumption, which is unrealistic in the civil field; Second, reduce the unit area of photosensitive elements and integrate more photosensitive elements on the existing horizontal CCD area. However, this method will reduce the unit photosensitive area of photosensitive elements, reduce the overall sensitivity and dynamic range of CCD and affect the image quality.
5. What are the characteristics of 5.CMOS?
In recent years, the development speed of CMOS is quite good, and it has great potential to compete with CCD-even the top DSLR (Single Lens Reflective Digital Camera), Kodak DCS/KOOC-0/4N and Canon EOS/KOOC-0/DS all use CMOS imaging.
Compared with CCD, CMOS has two outstanding advantages:
1) has low price and simple manufacturing process. CMOS can be produced by ordinary semiconductor production line, unlike CCD, which requires special production process, so the manufacturing cost is much lower. Moreover, the size and yield of CMOS are not as limited as CCD.
2) Low power consumption. Although there is little difference between CMOS filter layout and CCD, the circuit structure of photosensitive unit is very different. Each photosensitive element of CMOS has an independent charge/voltage conversion circuit, which can independently amplify and output the electrical signal after photoelectric conversion-this is much faster than CCD collecting all the signals and then amplifying the output. Moreover, the photosensitive element of CMOS only works during photosensitive imaging, so it saves electricity compared with CCD. However, CMOS also has disadvantages. If there are many imaging actions when using a digital camera, CMOS will heat up due to the changeable current when it is started frequently, which will lead to disorder and affect the image quality.