TIR optic VS. collimator
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csshih
Flashlight Enthusiast
I am under the impression that collimators are usually aspherical lenses, and TIR optics are..well, TIR optics. example: malkoff dropins, some surefire lights
Thanks for the quick answer. It seems to me that lights with optics like the Malkoffs, Rayovac 4W 3C, Taskforce 2C and so on get called collimators and lights like Surefires, Inova's old TIROS and the Gerber Firecracker, all lights that have that highly focused narrow beam get called total internal reflection optics. Every collimator I have seen are flat up against the inside of the window, TIR optics that I've seen tend to be hemispherical looking in the middle or the whole optic and are not flat.
Collimator is a general term that applies to anything that bends light into a straight line, so it can apply to many different kinds of optics. Even a parabolic reflector acts as a collimator.
TIR optics (couple different kinds):
Fresnel optics:
Aspheric optics:
bshanahan14rulz
Flashlight Enthusiast
Is it even theoretically possible to have an area lightsource like an LED be precisely collimated? so-called collimator TIRs for LEDs seem to make a hazy dot that is far from collimated, as the dot is twice the diameter of the TIR by the time it is only a foot away.
Also, assuming the same optic based on a point-source, would cutting the die image size down by 4 (so that the die is 1/4th the size), would the projected "dot" be 1/4th the size at a given distance too?
Also, assuming the same optic based on a point-source, would cutting the die image size down by 4 (so that the die is 1/4th the size), would the projected "dot" be 1/4th the size at a given distance too?
It is a relative thing. There is no such thing as perfect collimation as you would have to have a light source that was infinitely small.
Not even lasers can do this.
That should be the case. Smaller die image to project = smaller projection.
alpg88
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Old thread, interesting too, but I don't think we have it answered,
so. i think i know the answer.
none of "collimators" used in any flash light or bulb, are really true collimators. but lenses\optics, true collimator has angle of 0* the light is focused in parralel,(as much as it gets in real world), just like laser. since no flashlight uses 0* beam or straight line, they aren't collimators.
tir is one way to call "lenses\optics" since all work on principle of reflection at the point of density difference. so basicly all realy tir optics regardless of price, and quality.
my guess high quality optics calld tir, just to diffrenciate from millions of cheap lenses.
so. i think i know the answer.
none of "collimators" used in any flash light or bulb, are really true collimators. but lenses\optics, true collimator has angle of 0* the light is focused in parralel,(as much as it gets in real world), just like laser. since no flashlight uses 0* beam or straight line, they aren't collimators.
tir is one way to call "lenses\optics" since all work on principle of reflection at the point of density difference. so basicly all realy tir optics regardless of price, and quality.
my guess high quality optics calld tir, just to diffrenciate from millions of cheap lenses.
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Well I think the question was answered to a reasonable degree. The premise of his question was wrong because a TIR optic is a collimator. This was answered already. I think what he meant was the difference between a TIR optic and a lens like the aspherics people like to use. TIR means Total Internal Reflection. That is quite different than the aspheric lenses people use which utilize refraction rather than reflection to bend the light into collimation. It has absolutely nothing to do with the quality or lack thereof.
Regardless of what he meant that first picture is a TIR lens.i think he meant this
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I second Saabluster,
They are both Collimators, as defined well in post #4.
And they are both TIR also, as both use total internal reflection principle (not necessarily 100% reflection efficiency). One looks higher quality than the other, may be more efficient.
DX cheap "Collimator" is a "brother" of the expensive Surefire TIR
By sticking to a special name, Sure fire wants to distant itself from the cheapened "Collimator" street name. The same reason most people don't know Icon, the made in China light, is owned by Surefire, Ltd. Careful marketing differentiation to protect surefire brand reputation & retain customers who "will never buy a made-in-china light".
Smart marketing!
They are both Collimators, as defined well in post #4.
And they are both TIR also, as both use total internal reflection principle (not necessarily 100% reflection efficiency). One looks higher quality than the other, may be more efficient.
DX cheap "Collimator" is a "brother" of the expensive Surefire TIR
By sticking to a special name, Sure fire wants to distant itself from the cheapened "Collimator" street name. The same reason most people don't know Icon, the made in China light, is owned by Surefire, Ltd. Careful marketing differentiation to protect surefire brand reputation & retain customers who "will never buy a made-in-china light".
Smart marketing!
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alpg88
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if the light has a beam angle of more than 0* it can't be true collimator, http://en.wikipedia.org/wiki/Collimator, we wrongly call some tir lenses collimators. i have to admit i used to do it to.
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It is not wrong to call a TIR lens a collimator because it is one. But then so are reflectors and lenses so it is a rather generic descriptor. If you look at the definition of collimator you will find that it is not so narrowly defined as to mean only beams of 0 degrees either.
alpg88
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yes, in real world it is imposible to have perfectly 0* beam, that is true.
here is defenition that i found so far.
Collimated light is light whose rays are nearly parallel, and therefore will spread slowly as it propagates. The word is related to "collinear" and implies light that does not disperse with distance (ideally), or that will disperse minimally (in reality). A perfectly collimated beam with no divergence cannot be created due to diffraction, but light can be approximately collimated by a number of processes, for instance by means of a collimator. Collimated light is sometimes said to be focused at infinity. Thus as the distance from a point source increases, the spherical wavefronts become flatter and closer to plane waves, which are perfectly collimated.
The word "collimate" comes from the Latin verb collimare, which originated in a misreading of collineare, "to direct in a straight line".[
A collimator is a device that narrows a beam of particles or waves. To "narrow" can mean either to cause the directions of motion to become more aligned in a specific direction (i.e. collimated or parallel) or to cause the spatial cross section of the beam to become smaller.
well i guess you have a point too.
here is defenition that i found so far.
Collimated light is light whose rays are nearly parallel, and therefore will spread slowly as it propagates. The word is related to "collinear" and implies light that does not disperse with distance (ideally), or that will disperse minimally (in reality). A perfectly collimated beam with no divergence cannot be created due to diffraction, but light can be approximately collimated by a number of processes, for instance by means of a collimator. Collimated light is sometimes said to be focused at infinity. Thus as the distance from a point source increases, the spherical wavefronts become flatter and closer to plane waves, which are perfectly collimated.
The word "collimate" comes from the Latin verb collimare, which originated in a misreading of collineare, "to direct in a straight line".[
A collimator is a device that narrows a beam of particles or waves. To "narrow" can mean either to cause the directions of motion to become more aligned in a specific direction (i.e. collimated or parallel) or to cause the spatial cross section of the beam to become smaller.
well i guess you have a point too.
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i think he meant this
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Actually this IS exactly what I was talking about. Take note of the optic shapes, the are exactly as I previously described, the "collimator" is flat on the top and would sit flush against a window or may even be used without one and the SF TIR is more rounded, as is the Inova TIROS optic and the optic used in Gerbers Firecracker. What had me wondering was the fact that most optics labeled as collimators usually had a floody beam or a rather normal beam, where as the optics that were call TIR optics had those narrower beams that the before mentioned lights have.
fyrstormer
Banned
If you think collimating light is hard, imagine trying to collimate neutrinos. Apparently there's some defense-related research going on in this area, because an extremely powerful neutrino beam can detonate nuclear weapons, and the military would very much like to have a gun they can use to destroy nukes anywhere on earth with no lead-time. (the really fun part is, since neutrinos interact so weakly with "normal" matter, you can point the gun at the ground and the neutrinos will go straight through the planet and out the other side -- but try finding something they'll reflect off of so you can collimate them in the first place!)
