A few weeks ago I came across a part of Sam Goldwassers' Laser FAQ talking about the SONY blu-ray diode that you find in SONY blu-ray DVD players and PS3's. I haven't been paying much attention to the new blu-ray format as I still think standard definition DVDs look pretty good through a good video scaler to a good HD projector... I also wanted to wait for the whole blu-ray / HD-DVD format war to end before I invest in either one. (as of right now it looks like the blu-ray format is winning). But the article I saw on the blu-ray diode really got my attention. What I didn't know about blu-ray diodes was that they actually emit visible blue light! 405nm to be exact. I had assumed them to be in the UV range (my bad assumption), but again, this way from my lack of knowledge on this new media format.
So of course I had to have one. There are a few companies out there that have been buying blu-ray format players, scrapping them for the diode and making laser pointers out of them. Then they charge ridiculous amounts of money for them, even thousands of dollars. But another good source of the blu-ray diode is the SONY ps3... more specifically a SONY replacement pickup assembly for the PS3. I found one on eBay for $50.
I received it yesterday and immediately begin tearing it apart. Here is the complete module:
Inside is a very cool array of lenses and beam-splitters:
Here is a close up of the laser diode pinout. This diode contains a 405nm blue diode, a 650nm red diode and a 780nm IR diode all in one package.
An even closer view of the assembly. The laser diode can be seen on the far right. There are some interesting optics and filters in here. Several of the filters are actually small LCD's.
The laser FAQ lists this diode to be running at safe levels around 4.5v at 30 to 40mA. Just to be safe, I limited my bench supply to 25mA before powering it up. I started the voltage at 0v and began slowly increasing. The first visible blue light was visible at about 3.2v. Brightness increased strongly up until about 4.10v, where my current limiting went into effect.
At this current which is lower than the 30mA to 40mA others had tested it at, the diode was extremely bright!
Now I just have to add a collimating lens to focus the output into a nice spot.
The lens I am using wasn't the best, it came from an old red laser diode module. I need to do a little searching to see if I can find a better lens laying around.
The final step will be to make a small power supply to run the diode off of batteries and mount everything in a small enclosure. Hopefully I will be able to finish it this weekend. More / better pictures will follow.