optocoupler lightguide 2

[echecetmat]

Hello,

I am searching for a lightguide which could link a LED and a phototransistor on the same PCB print. The SMD opto-components are spaced by about 15mm, and should perform in conjunction with this light guide an hybrid optocoupler function.
Do you know where such a lightguide is available ?

Thanks.

Antoine

 

[cev]

Lots of companies sell rigid or flexible light pipes for PCBs. Try seraching for "PCB light pipes":

http://www.google.com/search?q=pcb+light+pipe

CV

 

[IRstuff]

If it's on the same PCB, why are you not using an off-the-shelf optocoupler or optoisolator?

TTFN

 

[echecetmat]

Answer to IRstuff.
You asked :
If it's on the same PCB, why are you not using an off-the-shelf optocoupler or optoisolator?

The requirements is at least 10 mm air-gap between IR sender and IR emitter, to meet some Ex-ia requirements. Such hich voltage optocouplers are rare (no second source), price is prohibitive and speed performance is not optimum. Therefore the idea to make it with standard opto components, linked by a light pipe. Searching in Google, as suggested by cev didn't bring me success, I found only light pipes for display purposes. This is the reason why I posted this message.

 

[IRstuff]

I still don't see a problem.

Worst case is that you cut a standard photoswitch in half and put a small shroud over the two of them. If this is really a controlled environment as far as light is concerned, a lightpipe is gross overkill.

If you absolutely insist on using a lightpipe, you could simply go to Walmart, find one of those Star Wars figures with an LED/plastic light saber and use that. Just about any solid acrylic pipe will pipe light to some degree.

TTFN

 

[nbucska]

What is the required speed? [Bits/sec]



<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032

 

[cev]

echecetmat,

It would help if you would specify if this is a production or custom PCB, amongst other details.

As IRstuff said, any piece of acrylic will be fine for a custom job. If you want better environmental isolation, just paint your coupler with a layer of white paint and then a layer of black paint.

cev

 

[echecetmat]

Thank you for your answers,
Unfortunatly I didn't found a solution for my request in your posts. I'm looking for an industrial solution, so it is not possible to split optocouplers in two parts, or hand paint some light pipes.
I am looking for a light pipe that can be clipped on the PCB board, over the SMD opto-components (standard), thus forming a compound optocoupler. It seems that such a light pipe doesn't exist as an off-the-shelf component. Ideally the components are distant of 14mm (optical center to optical center) thus ensuring a minimum gap between electrical parts of 10mm.
Perhaps is it due to patents (EP1376707A2 for instance) that prevents light pipe manufacturers to offer such product ?
To the question of nbucska : The speed of this hypothetical optocoupler depends on the used optical components, we aim to reach 2 to 5 Mbit/s with low-cost components.

 

[cev]

echecemat,

I think you should contact some custom light pipe manufacturers and have a custom part designed and fabricated. I don't think that patents should be a problem in such a case.

Go to the "photonics online" buyer's guide to find dozens of companies that do this sort of work:

http://www.photonicsonline.com/buyersguide/

There are numerous catagories under "Fiberoptic and Optoelectronic Components" which are of relevance to your problem.

CV