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Old Aug 30th 2019, 09:12 AM   #21
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Still don't get it, a comment is missing, but here again.


Got some stuff laying around,


3x beamerlens DELTA HD-6C ML focus AND zoom
2x beamerlens DELTA 781CP focus OR zoom
1x beamerlens DELTA 771CP focus OR zoom
2x beamerlens Toshiba 48-72mm 1:2.5-3.1 focus AND zoom

4x 76mm lens, focus60mm
1x led + holder + lens 40mm, focus=20mm
1x led + holder + lens 40mm, focus=27mm

1x lens 100mm focus=135mm
1x lens hollow 100mm, focus=200mm

Heatsinks with fan's.
A 100W led on 230V-AC. 2 leds 100W, with adjustable DC-DC pcb's.



I did determine the focus length by using a laserpointer.

The DELTA assemblies: have to determine the values.
Attached Thumbnails
Creating a parrallel lightbeam.-69252282_514344829320430_2619869216643219456_n.jpg   Creating a parrallel lightbeam.-69282785_1390490917756811_785316529347493888_n.jpg   Creating a parrallel lightbeam.-69416586_657467481416984_5203918955793612800_n.jpg  

Last edited by cobaltBlue; Aug 30th 2019 at 09:31 AM.
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Old Aug 30th 2019, 11:44 AM   #22
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Let's face it!

100Watts, must be an insane amount of Lumen!

I mean, a ( DIY) 1 or 3 Watt led as my bike's headlight is allready tremendous!

Also, this reminds me way back to almost 25 years ago!
From an old dia-projector, I built this lighteffect.
A big rotating disc with 6 small rotateable paterns in it at the place where
usely the dia is. The ligtsource was 'only' a 50Watt lamp, not a led!

One patern perticulary, existed out of 12 tiny holes, made with a needletip. In a circle patern only 10mm in diameter. Outside, a bit mist/foggy and that patern went easely over 100meters. From that point, it was like you watched into a tunnel of razorsharp lines passing me by from all around, almost like a laser!

I mean, only a tiny fraction of that 50Watt light source was 'free' outside the lighteffect-box and that allready gaves this effect!

mesmerising



Have a nice weekend!
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Old Aug 30th 2019, 05:02 PM   #23
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Originally Posted by cobaltBlue View Post
Got some stuff laying around,
1x lens 100mm focus=135mm.
You should be able to do something with those lenses ....

Biggest dia. would be best with a short focus ...

but you do need a compact source .... 10W would be OK , although it's a 1/10th the output of 100W the eye will see it as half the light output and being very small it will be fairly parallel ... only a few Euros each inc delivery

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Old Aug 31st 2019, 02:06 AM   #24
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Due of some test, I'm convinced that the idea with multiple Fresnel lenses will work, I'm not gonna put the time labor in it, it's not worth it and got other dedicated hobby. This is completely against my nature!

Tnx, oz93666. I understand less Watt with a dedicated lense-system will do perfect.

Searched around and found 20W led's, light source as small as a green pea, like your 10W one, oz93666.


20Watt:
https://nl.aliexpress.com/item/33010005106.html



But I prefer the disc allready mount:
https://nl.aliexpress.com/item/32757473209.html
Light source seems bigger, needs investigation...


Found also an RGB one 18W, same size, light surface,diamater5,9mm.
https://nl.aliexpress.com/item/32949606117.html


Next thing is to check the outgoing beamangle of those leds, so I can determine the lensdiameter and focuslength. Mostlikely I can use lenses I allready got.

For now, good weekend.
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Old Aug 31st 2019, 02:09 AM   #25
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The prictures:
Attached Thumbnails
Creating a parrallel lightbeam.-led-20w-5x5.jpg   Creating a parrallel lightbeam.-led-20w-disc.jpg   Creating a parrallel lightbeam.-led-18w-rgb-6mm.jpg  

Last edited by cobaltBlue; Aug 31st 2019 at 02:12 AM.
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Old Sep 1st 2019, 03:26 AM   #26
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Played around, and finaly git this setup.

Lens 1 and 3 no problem. Lens 2 gotta buy or have to proximate an existing lens.
Own lens or purchase.

This set up give a spot/distance-ratio of about 1%.
Theoratical, but ok...

The whole setup takes about 20cm.
Have tried to get it less, but then you keep messing around with the lenses
( diameter, focuslenght an position, with no improvement )
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Creating a parrallel lightbeam.-opt-100-1.png  
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Old Sep 1st 2019, 03:39 AM   #27
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But I quess, lens 2 as a Fresnell lens, will give the option for shorter setup.

The software doesn't have Fresnell.
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Old Sep 1st 2019, 11:02 AM   #28
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Wait...

just found out and realized that a Fresnell lens doesn't have this tipping point.
It means every beam 90deg on the Fresnell lens go trhough focus point.
A spherical lens has this tipping point that they go off and due of that one has invented the A-spherical lens ( correct me wehn I'm wrong ).

With knowing this all, I can easily order some round Fresnell lenses and this wil ease a lot!
( with a specific diameter and focuslength )

To be contineud...
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Old Sep 1st 2019, 05:50 PM   #29
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I don't quiet see the point of having multiple lenses , it will not help the quality or the parallelness of the light output ....

I know spotlight manufacturers do have multiple lenses ,I think this just means they can cut down on the total mass of the lenses ... they use glass , hot (80C) glass won't sag and bend ....

If they used one glass lens with a short focus it would be fat and heavy , so they have a small fat lens , which changes the angle of the light and then they can use a slim big lens , I think that's it ....

If you keep lens cool you can use one big plastic fresnel , these can have a short focus and never get fat
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Old Sep 2nd 2019, 04:23 AM   #30
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The maths of lenses has a couple of quirks...

To get it to focus parallel to a point,
the angle of the surface of the lens at the position at which the bending of the light beam occurs,
should be the angle of the surface of a section of a sphere.
However, this assumes that the bending of the light occurs at the centre plane of the lens.
The refraction actually takes place at the surface.

This approximation is OK for a slim lens, but starts to become problematic for thicker lenses.
This is one of the reasons why multiple (relatively slim) lenses are used rather than a single (fat) lens.
(There are other reasons, as OZ pointed out)

As you note, the Fresnel lens avoids some of these problems,
but it introduces other problems (e.g. it does not produce a nice sharp image).

It is possible to calculate alternative lens shapes that do not make the zero thickness lens approximation,
but the construction of the resulting lens shapes is difficult (and expensive).
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Last edited by Woody; Sep 2nd 2019 at 09:26 AM.
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