Here we can only identify by the appearance of the disc and the workmanship of the dye coating. High-quality CDs are usually made of strong materials and have very good elasticity when bent. If you feel that the hand feels soft and not flexible when you buy, you need to seriously consider whether this CD is worth buying. Secondly, because the reflection of light has a great relationship with the surface of the disc, the printing on the disc surface is also very important, and the method of identification is also very simple. If you hold it in your hand and look at it at an angle, a good disc has very little graininess. , And it is not easy to fall off when scraping by hand, the opposite is true for bad discs. The quality of discs is generally divided into: A, B, C and scrap grade.
According to the production stage of the master disk
The service life of a master disk is generally 100,000 pieces. The first tens of thousands pressed after the master disk is on the production line are A-level disks; the last tens of thousands are B-level disks; and the last tens of thousands are C-level disks.
|Production stage||Front section||Middle section||Last paragraph|
|Level||Level A disk< td width="153">Class B disk||Class C disk|
Divided according to quality inspection
The quality inspection equipment on the optical disc production line will inspect each CDR. For discs with quality problems, they are classified into A, B, C, and scrap grades according to their severity.
Generally speaking, B and C CDRs can meet the recording requirements in terms of electrical performance, that is, they can be burned, but there are defects in appearance and burning nodes, which may cause excessive data errors and burning. Failure; scrap products are not allowed to leave the factory. In the Chinese mainland market, the phenomenon of shoddy products is more serious, and some disc dealers even sell scrap discs on the market, harming the interests of consumers.
Identifying the quality
A and B grade discs are generally difficult to distinguish with the naked eye, only C and scrap grade discs with larger quality defects It is easier to distinguish:
Is the appearance of the disc normal: Whether the disc base is smooth and has no traces, and the shape is complete. If the recording surface and sides are obviously worn, it must be a scrap disc; if the laser mark of the disc is If the code and starting circle shape is abnormal, it may be a B or C grade disc.
Whether the coating is uniform and complete: Point the disc to the fluorescent lamp and observe from the reverse side whether the coating is uniform and without pinholes, especially the outermost part of the disc, and the disc with a defect in the periphery It is most prone to record errors and damage the disc.
Whether the disc has a protective layer: Observed from the side of the disc, if there is a protective glue, there is a protective layer, if not, the quality of the disc is quite poor.
A burned disc is usually written with ATIP information (in the innermost circle of the disc) before leaving the factory, usually with several consecutive 16 entries The system code represents some information, generally including disc manufacturer, nominal capacity, disc type, disc dye name code, disc speed, etc. Generally speaking, ATIP information needs to be read through specific software with a recorder. DVD_Identifier can be used to determine the manufacturer, dye layer and other indicators.
There may be a misunderstanding among many people here, thinking that the disc level is actually the Disk Sub Type sub-type information in the ATIP information, but this is not the case. The A, A- and other information in the Disk Sub Type are only the burning mode established by Sony and Philip, and have no direct relationship with the level of the disc. This is clearly stated in the technical orange book. However, combined with actual application observations, it can be known that the discs in the A+ burning mode are better than the discs in the A burning mode in all aspects. Therefore, most of the boxed discs are discs of Type A and above, in the bulk discs. If you encounter these discs, don't miss it.