1, VCD laser head is an optical system consisting of laser diode, objective lens, focusing coil, tracking coil, 1/4 wave plate, beam splitter prism, diffraction grating and cylindrical lens.
2. The wavelength emitted by the laser diode of 2.VCD laser head is generally 780nm (nanometer), and it can be clearly observed by naked eyes that it emits a red spot during maintenance. Its working current is tens of milliamps, its working voltage is about 2V, and its tube consumption is several hundred milliwatts. Therefore, the laser diode is equipped with a heat sink.
3. The objective surface of 3.VCD laser head is coated with purple or * * coating to improve the light transmittance and lens performance. Be careful not to remove this film during maintenance, otherwise it will reduce the efficiency of the laser head and even damage it.
4.VCD laser head can be divided into single beam, three beam and holographic type.
Matters needing attention in replacing VCD laser head
1. Due to the different motherboard designs of various VCD players, the arrangement order of optical heads may be different, sometimes just the opposite, which can be judged from the over-beginning terminals of focusing and tracking coils.
2. If the shape, tray and tabletting cover of the laser head are different, the frame should be replaced or modified as much as possible.
3. The electrical parameters of each laser head are slightly different. After substitution, the parameters of each working point should be fine-tuned, such as focusing, tracking balance potentiometer, lamp power gain adjustable resistor, etc.
4. It is best to test for one or two days after replacing the laser head to determine whether the performance is stable.
Replacing the laser head is a very meticulous and rigorous work. A slight difference will lead to the failure of substitution and even damage the laser head, so you should be good at summing up and think hard in practice.