Cd how is it made

I chose to digest the information on the Internet about this subject and rewrite in more simple terms so anyone can understand. Making a compact disc is a complicated process with a lot of details.

But in general the process can be divided into these following broad areas. A glass master is a very delicate piece. The requirements for a glass master are very stringent.

Listed below are the minimum requirements that a glass master has to meet. The glass substrate is first cleaned with ultrasound. For making sure there will not be dirt during the polishing process, the glass substrate needs to be electrostatics free. Once the de-statics is done, the glass substrate will undergo the polishing in a controlled environment.

In this step, a thin primer is applied to the glass substrate when it is spinning in high speed. The primer functions as adhesive to bond with the later applied photo sensitive coating. Once the primer is dried, another thin layer of photoresist coating is applied.

The glass substrate is then transferred to an oven and baked for about 30 minutes at 90 C o. In this step digital signal of the master is converted, through the Mastering Interface System, into high frequency signal and sent to the mastering reader. It also drives the laser beam to mark on the light resisting material on the glass substrate.

Laser beam is normally Kr gas excited with wavelength of nm. This is the step to develop the digital signal on the light resisting substrate. Chemical solution is used to wash away the part exposed to the laser, forming the pits and the lands. The chemical solution used is usually alkaline.

Its function is to dissolve the light resisting material hit by the laser beam. Since the glass master is too fragile to be used as an injection mold, a metal mold called a stamper is usually used.

Making a stamper from the glass master involves the metallization of the glass master and later galvanizing it with electroforming. The purpose of having a thin metal layer is to create the electrode for electroforming which thickens the metal to form the stamper. The Load Lock Chamber is for preparation only. Data is encoded by forming pits in the spiral track of the polycarbonate though the pits appear as ridges from the perspective of the laser. A space between pits is called a land.

A change from a pit to a land or a land to a pit is a "1" in binary data, while no-change is a "0". Pits are closer to the label side of a CD, so a scratch or other damage on the label side is more likely to result in an error than one occurring on the clear side of the disc. A scratch on the clear side of the disc often can be repaired by polishing the disc or filling the scratch with a material with a similar refractive index.

You basically have a ruined disc if the scratch occurs on the label side. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content. Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile. Select personalised ads. Apply market research to generate audience insights. These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies.

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