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HELP: mixed the OSRAM 450nm laser diode & LED diode

laserlands

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I have sold lasers on ebay. there is new item: 450nm laser module 50-80mw. it is made of OSRAM laser diode 450p.
a few days ago, a buyer bought one of this kind of laser but two days ago, he claimed that it is a led with a lens not a laser.
as everybody knows, laser diode itself cannot coherent. simply to say, a laser module = laser diode + driver + housing + focal lens.
I have explained so many times and asked him put the focal lens back, but he refused. I bet ten times of the item that he can test the laser by any lpm or any authority if it is not a laser but a led diode. but he seems not trust me.
I attach the picture which is taken by the buyer. in the picture you can see that the laser diode works great. and the buyer remove the focal lens aside.
then I will send the link to the buyer to improve what I said.
I need your help my old friends on this platforum. I need your professional knowledges to help the buyer and help me to improve my words.
 

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laserlands

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I forgot to say. although the laser diode is 50mw-80mw. we sell the laser module on ebay as 40-50mw.
 

n2stuff

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I looks like a 450nm diode to me and you can see in the picture the lens sitting next to it. Send the guy here and we will tell him he is doing it wrong.
 

lasersbee

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I have sold lasers on ebay. there is new item: 450nm laser module 50-80mw. it is made of OSRAM laser diode 450p.
a few days ago, a buyer bought one of this kind of laser but two days ago, he claimed that it is a led with a lens not a laser.
as everybody knows, laser diode itself cannot coherent. simply to say, a laser module = laser diode + driver + housing + focal lens.
I have explained so many times and asked him put the focal lens back, but he refused. I bet ten times of the item that he can test the laser by any lpm or any authority if it is not a laser but a led diode. but he seems not trust me.
I attach the picture which is taken by the buyer. in the picture you can see that the laser diode works great. and the buyer remove the focal lens aside.
then I will send the link to the buyer to improve what I said.
I need your help my old friends on this platforum. I need your professional knowledges to help the buyer and help me to improve my words.
Send your (obviously) Laser Illiterate customer here and we will explain
the fundamentals of Laser Diodes to him...:beer:


Jerry

You can contact us at any time on our Website: J.BAUER Electronics
 
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BShanahan14rulz

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I think the idea is, in order to keep the customer anonymous, to send this link to the customer after we have all agreed that this is a very nice, single-mode laser diode.

To the buyer: the smaller the laser cavity, the higher the divergence of the raw output. Long laser tubes are long enough that only the light that is already bouncing back and forth parallel is let out the end. A laser diode's "cavity" is so small, that it requires an external optic. Just a single, small-diameter lens is enough to turn this diverging beam into a collimated, low-diameter beam.

For an LED, the emitting area is so large that you must use a much larger lens to achieve good collimation, and you will end up with a really really fat "laserbeam"

Here's an exercise in thinking logically. Consider this picture of a typical 5mm LED and its output: http://www.pinbits.com/images/5mm blue.JPG

the output looks similar to the picture you have. HOWEVER, take a closer look and you will see that the output in the LED picture is created not from a bare LED, but from the LED being focused by the small lens created by the epoxy package. The photo of your laser diode in comparison, is the output from the raw laser diode, no lens in the beam path.

Try taking that lens that came with the laser and screwing it into the front of the module while it is pointed at a wall, and you will find that there is a certain point at which the lens turns the output into a spot. This indicates that the laser diode is positioned at the focal point of the lens, and this is how we turn laser diodes' raw output into a nice, thin beam.
 

Meatball

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^^And there it is. Nothing more should need to be said except..

I hope this customer also bought safety glasses. They obviously haven't the slightest of how to use a class 4 laser.... its scary really.
 

justinjja

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Here is a link with a small explanation of the difference between laser diode and led
Laser Diodes

It does explain that lasers diodes use lenses


But if he still doesn't get it
with a coustomer like this,
it might be best to just accept a return and give him a refund.
 
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laserlands

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thank you for all your help. yes, I have already sent the link to the buyer. hope he can visit this platforum and get more information.
:)
 

Benm

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One very obvious difference is the speckle. The photo quality isn't that great, but it looks like there is some speckle there to me, indicating that this is in fact a laser diode and not a led.

The elliptical brightness distribution also inclines me towards assuming it is a laser, although it is not impossible (just very rare) for leds to have such an output pattern.

Afaik there are few to no blue leds available in the package laser diodes come in either - if its a canned device press-fit into that aixiz i'm sure it is a laser. LEDs in such cans were available once, but only in (infra)red, and i don't think any have been produced since the 1980s.
 

conundrum

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VCSELs used in laser mice sometimes use the can type.
The more recent package has the laser and 64*64 CCD with optics and proximity sensor in a single flat plastic chip.
 




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