CCD is the abbreviation of ChargeCoupledDevice in English, which is a charge-coupled device. It is a special semiconductor device with many of the same photosensitive elements. Each photosensitive element is called a pixel. CCD is an extremely important component in the camera, it plays the role of converting light into electrical signals, similar to the human eye, so its performance will directly affect the performance of the camera.

 

There are many indicators to measure the quality of CCD, such as the number of pixels, CCD size, sensitivity, signal-to-noise ratio, etc. Among them, the number of pixels and the size of CCD are important indicators. The number of pixels refers to the number of photosensitive elements on the CCD. The picture captured by the camera can be understood as consisting of many small points, each point is a pixel. Obviously, the more the number of pixels, the clearer the picture will be. If the CCD does not have enough pixels, the sharpness of the picture will be greatly affected. Therefore, in theory, the number of pixels in the CCD should be as large as possible. However, the increase in the number of CCD pixels will reduce the manufacturing cost and yield, and under the current TV standard, after the number of pixels increases to a certain number, the effect of increasing the clarity of the shooting picture becomes less obvious. Therefore, generally a A million or so pixels are sufficient for general use.

 

A single CCD camera means that there is only one CCD in the camera and it is used for photoelectric conversion of luminance signal and color signal. The chrominance signal is completed by some specific color mask devices on the CCD combined with the following circuits. Because a CCD completes the conversion of luminance signal and chrominance signal at the same time, it is inevitable to have both, so that the captured image cannot meet the high professional level requirements in color reproduction. In order to solve this problem, the 3CCD camera appeared. 3CCD, as the name suggests, is a camera using 3 CCDs. We know that if light passes through a special prism, it will be divided into three colors: red, green, and blue, and these three colors are the three primary colors used by our TV. Through these three primary colors, we can generate signals including brightness. All TV signals included. If a CCD is used to receive each color and convert it into an electrical signal, and then generate an image signal after circuit processing, a 3CCD system is formed.

 

Compared with a single CCD, because the 3CCD uses three CCDs to convert red, green, and blue signals, the captured image is more natural than a single CCD in color reproduction, and its brightness and clarity are better than those of a single CCD. However, due to the use of three CCDs, the price of a 3CCD camera is much more expensive than that of a single CCD.

 

The CCD column in the digital camera specification sheet often says "1/2.7 inch CCD", etc. The "1/2.7 inch" here is the size of the CCD, which is actually the length of the diagonal of the CCD. "

 

Existing digital cameras generally use 1/2.7-inch, 1/2.5-inch, and 1/1.8-inch CCDs. A CCD is a collection of light-receiving elements (pixels) that receive light passing through a lens and convert it into electrical signals. In the case of the same number of pixels, the larger the CCD size, the larger the unit pixel. In this way, the unit pixel can collect more light, so it can theoretically be said to be beneficial to improve the picture quality.

 

However, the quality of digital cameras is not only determined by the CCD. The performance of the lens and the circuit that forms the image through the electrical signal output by the CCD can also affect the image quality of the camera. The so-called "large size CCD = high image quality" is incorrect. For example, digital cameras with 1/2.7-inch CCDs have not been criticized for poor image quality, although 1/2.7-inch is smaller than 1/1.8-inch size.

 

Nowadays, pocket digital cameras are becoming smaller and lighter, and most of them use small 1/2.7-inch CCDs for design considerations.

 

By the way, the "type" of 1/2.7 inch is sometimes written as "inch", but it is not the ordinary "1 inch = 25.4mm" here. Due to the combination of the camera tube and display method used on the camera before the CCD debut, it is customary to use a relatively special size. 1/2.7 inch is 6.6mm and 1/1.8 inch is about 9mm.

 

CMOS stands for Complementary Metal Oxide Semiconductor - a raw material used on a large scale in the manufacture of integrated circuit chips. Sometimes people mix CMOS with BIOS. In fact, CMOS is a readable and writable RAM chip on the motherboard, which is used to save the hardware configuration of the BIOS and the user's settings for certain parameters. The CMOS can be powered by the motherboard's battery, so even if the system loses power, the information will not be lost. CMOSRAM itself is just a piece of memory, and only has the function of data saving. The setting of various parameters in the BIOS should be done through a special program. The BIOS setup program is generally integrated into the chip by the manufacturer, and the BIOS setup program can be entered through a specific key when the device is turned on, so that the system can be easily set. Therefore BIOS settings are sometimes called CMOS.