Making High Quality Laser Diode Sockets.

[The_Doctor]

I've found a cheap easy way to make sockets for diodes where no photodiode is used.

RS part code: 228-0135
IC,socket,DIL,shrink DIP,turned pin,64 way
* Turned pin, low insertion force Shrink DIP sockets with a pin spacing of 0.07in
* The turned pins having a gold over nickel-plated inner contact with a tin-plated brass outer shell


£4.31 + VAT. Plus an hour of work. Result: 22 gold-contact sockets.
Total cost is lower than bought sockets, and the quality matches the best bought sockets in a much smaller size. The task is easy enough that the failure rate is low or zero.

Cut the IC socket into two strips of pins, and use a belt sander or coarse file to reduce the bulky side of the plastic to match the thin side, then cut at every third pin. To cut each strip I put them on a board and use a Stanley blade and a small hammer to gently tap the blade down till the bits fly apart, so if you do it that way, make sure you can't lose them. With some extra time you can grind off the plastic where the cuts were made, and maybe get the socket small enough to fit a 4mm bore like those on the LasIRvis collimator housings, which is useful because no commercial socket exists that small. The sockets are easily handled without this further work, so are ok in most places.

[stanwax]

Doc
get some pix up so we can see your quality west country work

Rob

[The_Doctor]

I'd say Oo'Ar, but I wasn't born here so I'm not qualified.
I ground their sides down like I said, it's worth the extra trouble to make them really small. I held them in snipe-nosed forceps to do that on a board with wet/dry sandpaper glued to it. I haven't got a zoom lens, so this image is as close as I can get. Ignore the green smears in the middle of the image, that's CCD damage.

The brass block is a test of indium based solder mounting. It works at 95°C or less. I haven't done enough of it yet to know how low I can get. The solder is an indium/bismuth alloy melting at 74°C (165°F).

[PNjunction]

These things look great! Do they add any resistance?

[Astroguy]

Here are some at the bottom of the page. I don`t know the price.

http://www.roithner-laser.com/Drivers.htm

[The_Doctor]

Here are some at the bottom of the page. I don`t know the price.

http://www.roithner-laser.com/Drivers.htm

I know, those are what made me realise it was either despair, or make my own. Given the ease and quantity you get from one 64 pin shrink dip socket, there is no contest. Try fitting those standard ones in a 4mm bore, too. Good luck.

Re resistance, I think it should be extremely low, this is a gold to gold contact made under good even pressure, it won't get any better than that. If you're using current controlled drive it won't matter, it would equate to a few extra nanowatts of waste heat.

[PNjunction]

Speaking of gold, a tiny swipe of Pro Gold on the diode pins probably couldn't hurt either. Love that stuff.

Since the RS part looked like it might be harder to obtain in the states, or at least more expensive to have one shipped from NSW or wherever, I looked around and found a very similar, high quality Mill-Max part. Lo and behold, the company is a 20 minute drive from me! They even appear to do sample requests, so I'll likely call them up.

Doctor - What are you using for contact to the leads? Solder, or those semi-collet looking contact clips made for these things? Spotted them in a datasheet somewhere while searching around.

[The_Doctor]

If I had those little collet clips I might not need these sockets. Got any more info about that? Anyway, the idea with the sockets is to solder to them to spare having to solder diodes. Specially useful if you want to risk high output at expense of short life.

Diode pins are actually slightly closer even than Shrink DIP (which equals the spacing across the diode's more separated pair). If anyone knows some than match the extra fine spacing between the closer pairings, please post...


Edit:
PNjunction, got a link to Pro Gold? Sounds cool. I'd go Googling but I think I'd get more garbage results than if I entered the word 'Deluxe', it's one of those phrases that make sensible searches almost impossible.

[PNjunction]

Will try to find that pdf datasheet again. Forgot at what point I saw it while searching, but shouldn't be hard to find.

Although the plan for me is to try to not blow any diodes, I suppose the reason for my interest in these things is that when building something, I try to "design" for easy serviceability as much as possible even when there's no real need to do so. The little details make me feel prouder of the final products... most of which are useless beyond belief, but hey, we're having fun.

Will definitely keep an eye out for smaller pin spacing if such a thing is made. Do you think it should be closer to approx. .065 - .060?

And yes, the Pro Gold!... which I should stop calling it that since the name's been changed to Deoxit Gold. Caig Laboratories makes Deoxit for contact cleaning, and the Gold is a protector/contact enhancer. I recommend the 100% solution for both products.

[The_Doctor]

Nice, I know Deoxit, I think, I ought to get some for the too-many wires and plugs around my rooms. I still think there's no substitute for just keeping them clean as possible with no films of any substance on them though.

Re spacings, it's likely 0.05" for the close pairings. The diode pins are forming three corners of a square. The square's geometry for 0.05 on a side would give 0.0707... (10th of reciprocal of square root of 2), which is so close to 0.07 of Shrink DIP. I never heard of a DIL/DIP socket so fine it was half pitch of standard 0.1 though.