Has anyone tried using IR lasers with the colimating lens replaced with a simple convex lens as a diffused source of IR?

Hey Ancalagon,

thanks fpr the link. Very informative. Do you have more of this pictures? It makes sense anyhow - excepting that the LED is not oriented towards the surface, but the little fancy mirror. So they are splitting up and scattering the lightsource into different spots. Man that must be a beast of a LED… I quess more the 50W That explains why they are having that gigantic heat exhaust behind the led

Ancalagon - 19 September 2009 01:43 PM

sandor - 19 September 2009 09:15 AM

pylin,

as you can see it in the movie, MS is not orienting the leds directly towards the projection surface. More likely the LED is shining horizontally and there is a glass-type plate in the front of the LED. I’m not sure, but i am quessing that the plate is a lens for scattering the light…

The plate is a simple piece of glass and has no special optical properties. The LED is oriented towards the surface and titled slightly outwards. However, it seems to me that Microsoft didn’t show one of the most important parts of the LED assembly in this video, which is a special mirror to focus the light on the four quadrants of the projection surface.

http://img9.imageshack.us/img9/9989/surfaceled.jpg

It is SFH 4740. http://catalog.osram-os.com/catalogue/catalogue.do;jsessionid=3FCE80C826DB2DE5CF66D5779F1AD9A1?act=downloadFile&favOid=020000000000fdc9000200b6

sandor - 20 September 2009 05:34 AM

Hey Ancalagon,

thanks fpr the link. Very informative. Do you have more of this pictures? It makes sense anyhow - excepting that the LED is not oriented towards the surface, but the little fancy mirror. So they are splitting up and scattering the lightsource into different spots. Man that must be a beast of a LED… I quess more the 50W That explains why they are having that gigantic heat exhaust behind the led

Actually the LED is oriented towards one edge of the surface. About half of the light is reflected by the mirror, the other half is oriented directly at the projection surface.
This is how the LED assembly is mounted: http://img23.imageshack.us/img23/6362/surfaceled2.jpg
The LED is a Osram SFH 4740 with about 24 W power consumption and 3.6 W optical power. The reflection of the LED is clearly visible in the raw images of the cameras.

Hmmm, that LED spec seems good, gotta search digikey.com or mouser.com for it.

Here is my LED, it is built in Luxeon form factor so that accessories can be used for it. For example, you can buy collimator for it that is intended for Luxeon. It is supposedly to be 3W, it has three separate IR leds in the package.

The first picture is the LED itself with wiring, the second one is constant current driver for it. The aluminum channel acts as heat sink. I am surprised that this LED does not heat up like those high powered Luxeon LEDs

$97 for one SFH 4740 at mouser.com

could you plz send some picture when they are on & shining?

incase anyone is interested - http://onecall.farnell.com/osram/sfh4740/led-ir-module-850nm-3-6w/dp/1603325?Ntt=SFH4740

Ancalagon - 19 September 2009 01:43 PM

sandor - 19 September 2009 09:15 AM

pylin,

as you can see it in the movie, MS is not orienting the leds directly towards the projection surface. More likely the LED is shining horizontally and there is a glass-type plate in the front of the LED. I’m not sure, but i am quessing that the plate is a lens for scattering the light…

The plate is a simple piece of glass and has no special optical properties. The LED is oriented towards the surface and titled slightly outwards. However, it seems to me that Microsoft didn’t show one of the most important parts of the LED assembly in this video, which is a special mirror to focus the light on the four quadrants of the projection surface.

http://img9.imageshack.us/img9/9989/surfaceled.jpg

Ancalagon - I know you’ll have the answer

Do you know for sure that this is ‘ONLY’ glass.  For good IR diffusion you use QUARTZ - very expensive.

Note there are no reflectors here either - are the reflectors in all the production tables?