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LED optics

Q

Quack

Jan 1, 1970
0
Hi,

I have seen some LED driven devices project a little rectangle
(unfilled) at a distance of upto 10cm or so - i am wondering how this
is done.
Is it just a matter of a special lense infront of uBright LED's ?
If so, where can i get these lenses, and what are they called.

I cant seem to find anything through my google searches.

(i can not take apart the above mentioned device to have a closer
look, but it is definantly LED's).

Alex.
 
J

Jerry G.

Jan 1, 1970
0
It may have been an LED laser, something like a laser pointer. It would
then have the proper defuser in front of the beam output at the level of
where it has to be collimated.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


Hi,

I have seen some LED driven devices project a little rectangle
(unfilled) at a distance of upto 10cm or so - i am wondering how this
is done.
Is it just a matter of a special lense infront of uBright LED's ?
If so, where can i get these lenses, and what are they called.

I cant seem to find anything through my google searches.

(i can not take apart the above mentioned device to have a closer
look, but it is definantly LED's).

Alex.
 
Q

Quack

Jan 1, 1970
0
It may have been an LED laser, something like a laser pointer.

Im 99% sure its just a normal LED.

For example, search for some 'IR proximity sensors' on
www.farnell.co.uk, rswww.com or digikey - read the PDF's and they
specifically say "Laser" or "LED" depending - and they mostly have
some kind of aiming spot too.
How are those done ?

Most of those are round dots, about 5mm dia. at 10cm - but i have seen
other shapes - and the PDF's would have to say "laser" if it contained
one.

These devices cant be opened without being completely ruined, and they
get very expensive :(.

Alex.
 
M

Martin Brown

Jan 1, 1970
0
Quack said:
I have seen some LED driven devices project a little rectangle
(unfilled) at a distance of upto 10cm or so - i am wondering how this
is done.
Is it just a matter of a special lense infront of uBright LED's ?
If so, where can i get these lenses, and what are they called.

Almost certainly it is a combination of a mask illuminated by an LED and
projected by a crude convex lens. Like a slide projector only smaller.

Regards,
 
P

Paul Hovnanian P.E.

Jan 1, 1970
0
Jerry G. said:
It may have been an LED laser, something like a laser pointer. It would
then have the proper defuser in front of the beam output at the level of
where it has to be collimated.

I have a cheap laser pointer that came with a set of graphics 'masks'.
These appear to be some sort of holograms that just snap over the end of
an otherwise standard, inexpensive laser pointer. There are no optics
invoved (other than those in the pointer) and the masks look like clear
flat plastic under ambient light.
 
Q

Quack

Jan 1, 1970
0
Almost certainly it is a combination of a mask illuminated by an LED and
projected by a crude convex lens. Like a slide projector only smaller.

Yes, it must be - thats what i think.

(as for the laser comments, its really not bright/high contrast enough
to be a laser, i know the laser graphic thingies mentioned above, and
its nothing like that - at over 10cm it would be barely visible in
this case)

So, assuming its just some mask/lense arrangement, does anyone know of
anywhere these can be purchased, if they are a standard thing ?
Perhaps there are LED's available with this kind of lense 'built in',
and can be used normally without having to make anything special.

Alex.
 
S

Smiley

Jan 1, 1970
0
I strongly suspect that this is a diode laser pointer that has a
hologram at the output. You can buy them pretty cheaply with as many
as 40 different images you can change out.

Joe
 
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