What is inside a DVD player? (5 of 5)
In this video we explore the laser assembly inside a DVD player. Created by Karl Wendt.
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- Why are 2 magnets placed next to the lens?(7 votes)
- It is probably to adjust the position of the lens with the help of a coil.
It's like if the lens was sitting between 2 springs but with better accuracy and speed at this scale.(3 votes)
- What's up with that QR code?(4 votes)
- It's a good way to store part number, serial number, etc in a small package(7 votes)
- What do the magnets do in the DVD player?(5 votes)
- they hold the laser in place, so it does not move(4 votes)
- What happens if you put a DVD in upside down. Will it still play or not. Why?(3 votes)
- it wont because it has paint on one side and paint doesn't reflect light in basic terms(2 votes)
- is there a chance that a DVD player can be advanced in the future.(4 votes)
- how do cd players send messages to one another(3 votes)
- how much time does it take for the laser to go through all of it.(1 vote)
- How light collector detects the difference in bumps in DVD , will the light intensity decreases when laser light falls in those bumps ?(1 vote)
- so how does burning info onto a disk work?(1 vote)
- don't take my word for any of this I may not be right
there are tiny information storing crystals (possibly tellurium) and when you flash a laser at the crystals it can change the state of the crystal kind of like a flip- flop circuit
- Why does the laser have to move back and forth to read the dvd(1 vote)
- The data track for the disc is in a spiral pattern, so the laser has to change focus from near the center outward to read all of the data.
- [Narrator] Okay so the way a DVD player works is there's a spinning disc right here. That's our DVD. And so it spins around and there is underneath of it there is a motor, and that motor spins causing the disc to spin. And then there is a lens and a reflector, and a laser diode. And the laser diode shines the light on the reflector, it goes through the lens focuses on the DVD, and this whole part right here moves out as the DVD spins. And what happens is the DVD reflects the light back down here and there is a light collector. So the light collector says oh, okay. This is a pit or a bump and it sends that information via pulses of electricity back to the micro processor. So now we're gonna look at the laser assembly. It's comprised of a number of parts. It has a laser diode. It has a series of reflectors. It has a lens. It has a laser or a light sensor. And it has an adjustment mechanism. So the first thing I'm gonna do is take this covering off. I had already loosened it to make it a little easier to get off. And you can see right here there are two neodymium magnets. I think they're neodymium because they're very, very strong for their size. And that means it's a rare earth magnet and they tend to be very, very powerful permanent magnets. And then, right here you can see there are two different coils out of copper. And there are two coils out of copper there. And the lens is mounted on these wires in between and it can shift and move. So I suspect that that mechanism allows for fine tuning adjustments of the lens. All right. So let's go ahead and see if we can take apart this DVD player. So we'll pop this prism off here. So this sensor collects the reflected light and sends that information back. Now let's see if we can there we go. And there's the laser diode. So that's the little guy that shines the light, the laser light that gets read, that hits the disc and gets reflected and read by this sensor.