The making of glass master plate
Optical disc manufacturing, and burning disc is a different concept, first of all, the quantity is larger, and the process is more complex.
First of all, we need to make a master plate, which can be used as a mold to greatly speed up the efficiency of production and reduce the cost. However, because it is impossible to use laser to directly engrave the pit signal on the hard metal master plate, we must go through some procedures to achieve.
You must first prepare a thick glass substrate in the shape of a round plate and place it in the in-line mastering machine. The machine washes the glass substrate (usually using nitric acid or a dissolute substance) and then coats it evenly with what is called “photoresist” (PR, a light-sensitive substance) in a thickness of 130 picometers (10-9). After drying for about 20 minutes, the laser can record the signal on the layer of PR material.
The computer reads the data from the DLT and interprets it as “on and off pulses” (creating data pits). The laser beam burner (LBR) uses laser light to illuminate the PR material and burns information pits on the PR material of the glass substrate. This step is just like the exposure of the film in the camera box when taking a picture. LBR only notes the hole signal on the PR material (causing some chemical changes). Just like the development process after the completion of the film shooting, the marked glass substrate should remove the PR material after the reaction, so that the hole signal on it is really the same as the content of the DVD Video disc to be suppressed. In this way, the production part of the glass master plate is completed.