Mention the optical drive, I think of the first computer that I would buy in college, and the first computer in the computer city group with my roommate, in order to save the cost of an optical drive, only one optical drive was installed on the two computers, or guess who installed it. Now optical drives are rare, they have been replaced by U disks and network disks, technology is improving, products are changing, and the years have spared whom.
Well, the years are fair, let’s take apart an optical drive today and see what magical design and construction is inside. The image below shows an optical drive on a Dell notebook that has been scrapped and the optical drive is shelved as a separate part.
The front photo of the optical drive, with a nameplate affixed to the front, which reads Made in China. We all know that the optical drive was invented by the Japanese, and Made in China means that it is OEM production in China. At present, although the situation has improved, there are still many such OEM factories in our country, which are labor-intensive industries. At present, our country has introduced many relevant policies to promote industrial upgrading and transformation, and the transformation of labor-intensive industries into high-tech industries.
Made in China
The optical drive does not have power and cannot eject the disc case. The front cover is removed and the disc case is withdrawn, revealing the PCB, components, and connecting wires at the bottom.
Remove the front cover and pull out the disc case
Next, remove the PCB board with a chip on the back and unknown function.
PCB hidden inside
The main parts are concentrated on the disc, and the disc box is disassembled to reveal the plastic film PCB at the bottom. This piece mainly has three parts: motor, laser platform, laser platform moving shaft and disc box lock.
Circuit on the back of the disc case
Let’s take a look at the motor part, which provides the power to spin the inserted disc. After disassembling, it was found that the PCB board, iron plate and motor were fixed together. The shaft in the middle of the motor does not rotate, fixed on the iron plate on the back, the enameled copper wire is welded to the PCB, and the iron cover of the motor is surrounded by a circle of magnets and can be rotated. It is not easy to disassemble the motor and needs to be washed down with a hammer.
The disc case latch is designed very cleverly, and the disc case can be automatically snapped when pushed into the optical drive. When you want to open the disc latch, press the switch to turn on the solenoid coil, and the coil releases the latch, causing the disc case to pop out.
Disc case latch
Next is the laser platform part, the laser platform is responsible for reading out the information on the disc, which is the most core part. The whole platform is made of a whole piece of metal material (I don’t know what metal, do you know?). is machined, and other parts are fixed on it.
Laser platform section
One of the most important parts is the original part of the laser optical path, and I removed the laser head, various mirrors and sensors, and restored the original placement position, as shown on the right side of the figure below. The lenses are very small, but the polished ones are very flat, and they are all very easy to break. These require very precise installation and polishing, and it is very surprising that there are such precision products, and it is not an exaggeration to call them works of art.
Laser optical path
The laser head is located directly above the disc and reading data from the rapidly rotating disc requires very high precision. The laser head is supported by six elastic wires in a rectangular frame of permanent magnet, and the position of the laser head can be fine-tuned through the coil on the laser head to achieve accurate reading of the data on the optical disk.
The laser platform moving axis is controlled by a stepper motor, which drives the threaded shaft to rotate and also drives the laser platform to move. The entire shaft is relatively precise, but it needs to be aligned with the rapidly rotating disc, and it is estimated that it also needs the support of software algorithms, and the hardware with errors is fine-tuned through the control algorithm to keep the whole system in a stable running state.
The laser stage moves the axis
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