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Does module lens size effect brightness?

zxn474l

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I was wondering if a module's lens size effects the visible brightness of a beam...I mean for example a 200mw 650nm red in an Aixiz Module with a glass lens vs a 200mw 650nm red laser in a mini module with a very small fixed "infinity" lens setting? The smaller module would seem to be brighter right in theory because the same amount of photons are packed in a smaller area beam verses a large to small beam comming out of the Aixiz module right? I want to build a really bright 640nm red laser module using a mini brass module with glass lens at 250mw! I saw on listed on a web site...I think it would be alot brighter than a 650nm red at 200mw right due to the power is moer and the nm is lower and aperes brighter to the eye...just one thing different about the 640nm diode it has an emitter size of 60 vs the 650nm 5. is that going to make a difference? Will the 640nm larger emitter allow for burning matches or poping balloons...it is 250mw after all but still a larger emitter.
 

G Fourty

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I can understand how this could seem to make the beam appear brighter, but I believe the biggest factor is wavelength. You eyes just simply don't see red like they do green, blue, and yellow. It may appear slightly brighter, but I don't believe it will make it that much more visible.

-Greg
 

Moptsp

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As long as the lens is capturing all the energy, size isn't going to bother, at least not size as in the lens diameter.

But yes, the more focused the energy is per x^2, it will be brighter.

As G Fourty said though, we don't see red as well as green, so it will never be "brighter" to the human eye when comparing the two wavelengths of same amount of energy.
 

Hallucynogenyc

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As long as the lens is capturing all the energy, size isn't going to bother, at least not size as in the lens diameter
No way. Asuming you are using the same power and the same wavelenght and in the same ambient light conditions the beam diameter will affect A LOT the beam visibility. Just use a beam expander and you will see if it affects or not lol
 

Moptsp

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I didn't say the beam diameter, the lens. :p

Basically, this is where I'm getting.
If you were to go buy two pairs of binoculars of the same magnification, and one had larger lenses than the other, it would grab more light than the other.
So you would see a brighter image.

The same has to go for a laser as it's light too, I would think.

-Moptsp
 
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Hallucynogenyc

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Maybe I'm missing something, but if you mean the outer lens, their diameter equal to the beam diameter.

Anyway you are messing up concepts.

You see a clearer and brighter image on a binoculars with bigger lens because the light is coming in, and the more light that comes in the more light you get.

On a laser it's the reverse effect. You produce light inside and focus it with the lens to "shoot" it out. But, the smaller the lens the smaller the diameter, and a smaller beam will be brighter than another one of the same power and wavelength.

So you might be thinking now that then why aren't we using very small lenses always. The answer is that the lens must also capture all the light coming from the diode, so a small lens wouldn't get it all.

Also, a part from this a bigger lens allow you to adjust the focal point better, so there are many things to consider when choosing a lens.

Maybe you should study some optics physics and you would understand ;)
 

Moptsp

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Maybe I'm missing something, but if you mean the outer lens, their diameter equal to the beam diameter.

Anyway you are messing up concepts.

You see a clearer and brighter image on a binoculars with bigger lens because the light is coming in, and the more light that comes in the more light you get.

On a laser it's the reverse effect. You produce light inside and focus it with the lens to "shoot" it out. But, the smaller the lens the smaller the diameter, and a smaller beam will be brighter than another one of the same power and wavelength.

So you might be thinking now that then why aren't we using very small lenses always. The answer is that the lens must also capture all the light coming from the diode, so a small lens wouldn't get it all.

Also, a part from this a bigger lens allow you to adjust the focal point better, so there are many things to consider when choosing a lens.

Maybe you should study some optics physics and you would understand ;)
That's exactly what I said?
The only point I'm making is once the lens is large enough to capture all the energy from the diode, lens size will no longer change the power of the laser.
You can focus the energy to a smaller area though. But it's not more energy. It's going to appear brighter because the energy is focused on a smaller area. There is more energy per x^2.

Thanks all I'm saying.

And yeah, I read his post wrong. I though he was talking about power, not brightness. Sorry for the confusion.
 
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