Novelty laser gobos?

[norty303]

I expect you've all seen those little caps for laser pointers that allow them to project a heart or star or similar. And those twinkle lasers that do a similar thing.

Well, how are they made, is it a gobo or grating? Someone has asked me if I know where they could get a custom one and I'm not even sure what I'm looking for.

[andy_con]

do a search there was a post a few years ago about it.

cant remember many details about it though sorry

[frostypaw]

It's a holographic grating iirc, I rescued a bunch from a Smirnoff pointer I had but think it turned out they were wavelength dependent and very fuzzy away from the 650nm original illumination.

Struggling to find a sane link though but a supplier or two shows up here eek but they're computer generated so anything should be doable. would be interesting to know how expensive it is if you do find out

[mixedgas]

Laserlands in China?

Ask on LPF, there was someone advertising the process, but I cannot find the thread..

Steve

[Eidetic]

They are Diffractive Optical Elements (DOEs), and are produced by etching multi-level patterns on quartz substrates and then replicating those by embossing or casting into acrylic. The mastering is very expensive with long lead times, like tens of thousands of dollars and 3-6 months. Similar effect can be had by making holograms using relatively cheap equipment. Real holograms, not fauxlograms like the crap promoted as holograms in the past few years. Here's a great reference that covers the technology completely, written by my friend Bernard Kress.

http://www.amazon.com/Digital-Diffra.../dp/0471984477

[catalanjo]

.....by making holograms using relatively cheap equipment........

That bit sounds interesting !
Cheers

[zerowaitstate]

FOLLOWING UP ON Bernard Kress, some interesting stuff

https://www.svforum.org/sites/defaul...al_optics_.pdf