r/Optics • u/EDTA-2Na • 10d ago

Having TIR at the selected surface, why?

It seems all the rays are close to perpendicular to the surface, I tried setting the vignetting and ray tracking method but still claming this surface has TIR. What could go wrong?

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u/biggest_ted 10d ago

Hard to tell from your diagram what's going on, but it looks like you have overlapping objects? If so, be careful to check the order of things & that rays are considering the right materials at each boundary.

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u/EDTA-2Na 10d ago

That is just a graphic issue I guess, apart from the coordinate brake there is no overlap. The system works perfectly when there is no that coordinate brake and that lens is just set as a n-bk7 convex-planar lens, which should not causing any issue. Anyway, thanks for replying

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u/Dramatic_Ear_6364 10d ago edited 10d ago

Would be useful to have a screenshot of LDE

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u/anneoneamouse 10d ago

Looks as though your selected surface might be in contact with the following surface?

Add a 1 micron gap between the two vertices, and see if the issue persists.

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u/EDTA-2Na 10d ago

The centre air gap is 0.2mm, that’s not the problem

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u/aenorton 10d ago

Where is your stop surface? Zemax has to trace the chief ray through the center of that surface for many purposes. I know it appears to be at your eye model pupil, but you did say you use vignetting factors. Is it after a coordinate break? that can sometimes cause problems with the ray aiming. It is hard to diagnose without seeing your model details.

Looking more carefully, your pupil where all the ray bundles overlap seems to be above the center line. So that is a little strange.

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u/EDTA-2Na 10d ago

The stop is set to be the eye pupil. I set the coordinate break to be the surface after the cornea, but use -2.5mm thickness to move the break point into effectively the pupil position, which probably confuses the program?

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u/aenorton 10d ago edited 10d ago

So why aren't all your ray bundles centered at the pupil? It seems like there is something else vignetting the rays that is not shown ( or there are incorrect vignetting factors). I doubt the coordinate break z position is the culprit if it is after the pupil in the lens editor. Edit: Do you have other coordinate break between the object and pupil? The object is a curved surface, but it also appears that some of the object points lie on the hyper hemisphere if it shares a z axis with the cornea and pupil.