confuse about condenser lens

use of aspheric condenser lens is to concentrate all light.
as i saw if all light rays coming parallel then and only then it will give spot of light.
if light rays are little bit inclined then??


will it concentrate all light.

sagar said:

use of aspheric condenser lens is to concentrate all light.
as i saw if all light rays coming parallel then and only then it will give spot of light.
if light rays are little bit inclined then??


will it concentrate all light.

Click to expand...

If you've ever used a magnifying glass to burn things, it's the same principle. To focus a certain distance, there is a point from a light source where all beams converge. Condenser lenses help to condense the beam to a narrower profile, not necessarily a purely focused spot. I'd love to have a light that throws beams parallel to the light...

dc38 said:

If you've ever used a magnifying glass to burn things, it's the same principle. To focus a certain distance, there is a point from a light source where all beams converge. Condenser lenses help to condense the beam to a narrower profile, not necessarily a purely focused spot. I'd love to have a light that throws beams parallel to the light...

Click to expand...

A coherent beam?

:devil:

sagar said:

use of aspheric condenser lens is to concentrate all light.
as i saw if all light rays coming parallel then and only then it will give spot of light.
if light rays are little bit inclined then??


will it concentrate all light.

Click to expand...

dc38's description of the way you move the magnifying glass in/out to FOCUS the beam...as too far away, vs too close, is NOT as concentrated a beam as when its "just right"....works for me.

For a flashlight, the idea is the same...so for an aspheric lens, you are trying to focus the beam so that a projection of the picture of the LED is projected off into the night.....just like a slide projector image is.


If you take a flashlight (Any one will do...) and hold a magnifying glass in front of the beam, and shine the beam on a wall....if you move the magnifying glass in/out, you will find the distance that puts a picture of the LED on the wall...and, that's how the aspheric lens works.

Thank you sir
but what will happed with aspheric condenser lens.

sagar said:

Thank you sir
but what will happed with aspheric condenser lens.

Click to expand...

I don't understand the question...can you rephrase it?

CPF has a strong echo. A condenser lens changes the path of light beams in a particular way. Here is a thread on it:

Clicky

It's important to note that full collimation requires an infinitely small source size. So using the sun and a magnifying glass can get a pretty nearly cylindrical beam, but it will slowly diverge (the beam diameter will expand with distance). Further, even a 'focusing' lens (Like a magnifying glass and the sun) has a limit of intensity defined by the apparent source size and the optic size.