I got into my hand broken DVD-RW burner. Its fate was clear :). In the mechanic
you can find two laser diode capable of burning the items. One is infrared (CD burner) and one red
(DVD burner). Both diodes have about the same order of magnitude performance and thermal effects (maybe the infra burn a little more).
Light from the infrared (IR) one is almost invisible (and therefore
very dangerous !!!). The red laser diode can also produce a powerful laser pointer or laser-show. I supply both
diodes with current 175 mA. Interesting is that the laser unit is a kind of prism that combines the two beams into
one. Therefore I didn't salvage the lasers from the unit (drive is not too old and diodes are some modern types
that do not fit into the optics of the laser pointer or laser printers). Aluminum cover of the
unit (besides the magnesium body) also serves as a heat sink, so it is better not to remove it.
Diodes have max operating temperature of 50°C and the temperature
should be as low as possible (higher temperature reduces life time and the efficiency). I soldered two cables to the unit
for both diodes and made current-stabilising power supply that allows you to switch the operation of infrared LEDs, red LEDs, or both at once.
(Please note that the operation of the both diodes simultaneously creates a lot of heat.) With the lens (movable lens close to the CD/DVD disc),
laser was focused a few mm from the lens. After removing the lens I get beam with a diameter of 5mm (ie laser pointer or
laser source for laser show). If you want to burn the items, replace the lens with a lens of smaller dioptres.
What you will find in different drives:
- In a DVD-RW there are 2 burning diodes: Red for DVD and infraref for CD.
- Weak red lasers 1mW
from DVD-ROM (read-only drives) are suitable only for a small laser pointer or poor laser show, they won't burn anything.
- V combos CD-RW/DVD-ROM (burning CD and read DVD...today a hangover), there's a burning infrared dide and weak red diode (as in DVD-ROM)
- And finally, the lasers from CD-ROM are absolutely useless :). I mention this list so I avoid
stupid questions whether the diode from a CD-ROM will burn. It will NOT!
Class IIIb laser
Warning! Laser diodes from DVD-RW drive are emitting visible and invisible
laser radiation and they are extremely dangerous! Their light can permanently damage the eyes.
You must never look into the working diode even without the lens or point it on a reflective surface.
Laser beam can cause burns or fire. This is usually a Class IIIb laser. Everything you do at your own risk.
Schematic of current power supply for double laser from DVD-RW burner drive with switch for selecting operation mode (RED - INFRARED - BOTH).
The resistor determines the output current to the laser diodes using the formula I = 1.25 / R. LM317 needs a heatsink.
The voltage drop of infrared laser diode is 2.15 V and the voltage drop of red one is 2.5 V.
to the right of the engine theres a laser unit, to the left theres a sensor of Light Scribe system (Used for printing images on the top side of the DVD directly
in drive. This sensor senses the angle of the disc).
Here you can see the faint light from Light Scribe sensor.
Red laser in read mode.
Location of lasers (infra one and red one)
Schematic of laser system (view from the bottom, without the aluminum housing). There is an interesting prism, which combines the two lasers into
one beam, and thus allows even the use of both diodes simultaneously. The angle between each beam is only 0.06�.
And here is a laser unit gutted
Both diodes with soldered cables.
Red laser diode.
Infrared diode. Its light looks faint compared with red diode, but the power is the same order.
CCD sensor is not much sensitive to it and the human eye even less. Here is the unit with the lens.
...and without lens (resulting to the laser pointer with parallel rays).
Burning a plastic box with an external lens (red laser).
It's burning !
laser beam. In addition to the main beam are seen the side beams.
Beam scattered by lens
Beam flying through the air.
Comparison with laser diode "F-LASER 5MW" with power 5mW (from GME). I used the current 48 mA, maximum is 50 mA.
It can be seen that 5mW laser beam is even weaker than the side beams of DVD-RW laser.
Laser pointed out the window.
Beam incident on the wall.
This is how the bare laser diodes look like (5.6mm). On the left you can see a classic diode, diode on the right is open-can type.
Open diode chip is unprotected and it is necessary to handle it very carefully! Guts of the diode must never be touched and must be protected
against dirt or dust.
Besides DVD-RW drives for table PC, you can also find interesting diodes in notebook (laptop) drives.
The disassembly of the notebook DVD-RW drive to get the laser diode.
Lased diode module. There are diodes with atypical case, so I left them inside.
Module after removing the unnecessary parts of the optics (front lens and angle mirror) and a cable soldered to the anode of red LED.
The cathode is connected with a heatsink and is not necessary to solder it. The entire module can be screw to additional heatsink for better cooling.
Compact laser pointer module from the notebook DVD-RW drive.
Laser module from notebook on heatsink for better cooling.
Laser module on heatsink. The negative wire is soldered to the module body to avoid unnecessary diode soldering.
Finally, some Videos - Ignition of 5 matches and burning the plastic.
Notebook DVD-RW disassembly instructions video.
Warning for lamers: The laser diode cannot be connected directly to the supply. You must use a current limiter or a resistor.
I wonder, how many people are so stupid, that they connect it directly to maybe 12V and they are surprised, that the diode
does not work. Please, read something about the VA characteristic of laser diode and about calculating resistors (Ohm's law) and
current stabilisers. Do NOT spam with questions like "I connected laser to 12V and it doesn't work. What i did wrong?".
No one will answer such stupid questions.