How does a disc store information, how does a disc store data, and how does a disc store data

Storage principle. There is a class of non-magnetic recording media that can form small pits after laser irradiation, and each pit is a piece of information. This medium has a strong absorbance capacity and a low melting point, and under the irradiation of the laser beam, its irradiated area is melted due to the increase in temperature, and the molten part is pulled into a pit under the action of the tension of the dielectric film, which can be used to represent a bit of information.

Therefore, the laser can be used to read out information based on the difference in the ability of the pit and the unablative area to reflect light.

When working, the data sent by the host is encoded and sent to the optical modulator to modulate the intensity of the output beam of the laser source to represent data 1 and 0; Then the modulated laser beam is written into the system through the optical path to the objective lens focus, so that the beam becomes a light spot of 1 size and is emitted on the recording medium, with a pit representing 1 and no pit representing 0. When reading information, the power of the laser beam is 1 10 of the power at the time of writing. The read beam is an unmodulated continuous wave, which is also focused into a small spot on the recording medium after passing through the optical path system.

There are no recesses, and most of the incident light returns; In the recess, the depth of the pit negates the reflected light with the incident light and does not return. In this way, the "1" and "0" information recorded on the medium is read out according to the difference in the reflective capacity of the beam.

1. Optical disc storage technology uses a laser to write and read information on the medium. This storage medium was first non-magnetic and later developed into a magnetic medium.

2. The information written on the disc cannot be erased and is an irreversible storage medium. When recording optical storage with magnetic media, the original written information can be erased, and new information can be written, which can be erased and writable for repeated use.

There are many advantages of storing information in the CD-ROM format: (1) the recording density is high, the storage capacity is large, more than 100 1000 times that of the disk, a standard CD-ROM has a data capacity of 650MB, which can store 100 million Chinese characters for text storage, and can support 74 minutes of storage of sound or live image; (2) Using non-contact reading and writing methods, the disc surface of Zhaoyuan will not be worn and bruised, and the bald head will not be easily damaged; (3) The information can be stored for a long time, and the storage life can reach 10 to 50 years; (4) High reliability, low requirements for the use environment, less mechanical vibration problems, no need for special shockproof and dust removal equipment; (5) The production cost is low, less than 10-8 cents per person**, and it is easy to copy in large quantities.

1. There are many points on the disc, and they are arranged on the disc one by one to form a constant velocity spiral;

2. When the laser head irradiates these points along the trajectory of the isokinetic spiral, there will be a reflection that comes and goes when it encounters a point and no point, and the photosensitive tube that reads the laser will read the pulse that comes and goes, which is read as "1" when there is a pulse, and "0" when there is no pulse;