Tips on how to identify TIR optics

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clemence's picture
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Tips on how to identify TIR optics

I’m a TIR lenses hoarder. I find it more satisfying than owning flashlights. Up to this date I have thousands of them. From expensive Gaggione to unknown dirt cheap lenses from Aliexpress. Sometimes when it comes to modify a light I had hard times indentifying those marked plastic bags. And in most cases, not all lenses stored in the same marked bags.
The hardest thing was to identify between close beam angles without put them into use. Big dies LED such as COB, XHP50/70, and quadtrix E21A, are all less sensitive to slight variation in optics geometries. And usually the minute differences can only be seenor perceived later after several days of uses. This is problematic especially in hard to replace (or reach) light engines.

Normally, you can see the difference just by eyeballing each lenses under magnifying glass. But some have very slight difference which only easy to spot used with small die LED. Below is the example of two almost identical plastic TIR lenses with OEM rated FWHM (with 1mm2 LED) of 40° and 60°:

Check if you can spot which is which. The only obvious thing is the right one was used and looks dirtier

From the side, you can see very small difference between the center lens focal point by their curvatures. It’s easier to check in picture than in real life. In reality, it’s VERY HARD to see.

So I found the easiest way is to place them on top of diffused even lighted surface. In my case I use my smartphone “front flashlight” screen. There are many free applications to convert your screen into a homogeneous soft light panel.

Still no real differences…..

But when you flipped them upside down, it’s now so much easier! The left one is the 40°. The 40° center lens has shorter focal lenght needed to collimate the beam more aggressively than the 60°. Thus, making the small surface micro lenses looks bigger.


Edited by: clemence on 11/08/2019 - 02:48
id30209's picture
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Very useful! Thx!

WTB Titanium 4sevens Quarks & Jetbeam TCR1

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Clemence. You are amazing.
This helps a lot!

Phlogiston's picture
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Thank you, Clemence!

I’ve managed to avoid it so far, but sooner or later, I will get my TIR optics mixed up…

lumenzilla's picture
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Thanks for the tips, Clemence. It’s a new knowledge for me.

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I like this it helps me focus.

Kame Sennin
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Many thanks ! This is very helpful !


Lightbringer's picture
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Yep, and as you see in the pix above, wider-angles tend to be more bowl-shaped, vs narrower-angles more cone-shaped.

When I’d try to use the plastic shoe to hold the lens above the LED somewhat in my S2+es, wider-angles (90° and up) just won’t fit, whereas 60° and narrower will.

09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

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I have to try this..

I bought several 45-degree and 60-degree TIR optics from Convoy store and accidentally mixed a few up before.
The 2 TIR optics looked very similar in external physical appearance, just like you mentioned.
I had to test install them on S2+ and check the beam pattern to differentiate.

I’ll try your method next time..

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Very cool.

Gunga's picture
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Thanks a bunch for the tip!

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Very cool pics! Thanks for the info.

I’d rather use my flashlight around the house than turn on the lights.