Homemade Scanning Laser Color Projector/TV

[Xer0]

How about just blanking CW lasers with a extremely rapid LCD or DLP?

 

[Kenom]

There has to be a solution cause coherent has a working model. We've all seen it on youtube with that news broadcast.

 

[ElektroFreak]

How about just blanking CW lasers with a extremely rapid LCD or DLP?

That's basically exactly what AOMs (acousto-optic modulators) do. Here's a link with more info on that: http://www.rp-photonics.com/acousto_optic_modulators.html

If you combine an AOM with an aperture or mirror, it will modulate the beam at very high speeds. The maximum speed depends on the AOM.

AOMs are the only practical way of modulating gas lasers, but they work great with DPSS systems. Coherent doesn't even build direct modulation capability into their green DPSS systems (or any of their DPSS systems that I know of), so an AOM is the only way to do it. AOMs are superior to directly modulating DPSS lasers in general since they eliminate any instability/mode-hopping.

I definitely wouldn't be at all surprised to see MEMS technology like DLPs involved in laser TV technology somewhere..

 

[Xer0]

Great... thanks! now we are a step further - we need AOM's in MHz Range for a Beamer

I definitely wouldn't be at all surprised to see MEMS technology like DLPs involved in laser TV technology somewhere..

Aren't they scanning alreay with a MEMS X/Y Mirror? at least Microvision does...

 

[Cyparagon]

As far as I know, the current laser TVs just combine the beams and feed the white beam to a DLP chip. Since there's no scanning needed and each of the DLP mirrors corresponds to it's own pixel, the chip acts as a PCAOM (albeit at only 60Hz or so)

 

[Xer0]

Ok. then this would be another way to do it, nor?

Combining RGB(r), expanding the Beam, fire to DLP so the back reflection goes of of Beamer

 

[ElektroFreak]

Is the DLP capable of controlling color blending? I always thought that in systems using DLPs, the incoming light is color-cycled, while the DLP controls the position of the scanning beam(s).

 

[MarioMaster]

Is the DLP capable of controlling color blending? I always thought that in systems using DLPs, the incoming light is color-cycled, while the DLP controls the position of the scanning beam(s).

Yeah older systems used a spinning color disk to rapidly cycle through colors, but newer systems use three DLP chips and a combining optic. So one DLP chip per color.

 

[ElektroFreak]

^Thanks! I thought that was how it works.. Is that some kind of laser chiller in your avatar?

 

[Xer0]

Outsch. 3x DLP... recombining the prozessed beams with a laser could be a challenge.

Maybe... just color cycle the laser too and use just one DLP? Assuming we change the color three times per frame its just 75Hz modulating speed instead of multiple Mhz!

 

[MarioMaster]

^Thanks! I thought that was how it works.. Is that some kind of laser chiller in your avatar?

Yeah it actually is a water chiller I built a few years ago, although it wasn't specifically designed for cooling lasers.

Back to the scanner - getting into AOMs and such, this would be a pretty pricey project for someone to make from scratch.

 

[Xer0]

I saw AOM's with driver on fleebay for 30$... mybe woth a try.

Is it possible to combine the beam first and then modulate by a AOM like a multiline Argon?

 

[ElektroFreak]

I have one of those AOMs, and the only problem with that idea is that those are coated for red HeNe wavelengths. The losses with green or blue is too high..

With a properly coated PCAOM you can combine the beams first. That would be the only practical way to build this kind of project. You wouldn't necessarily need three AOMs. One of the main functions of PCAOMs in laser show use is to control color intensity as you already know, so that would definitely be the way to go here.

 

[Xer0]

Ack. can you aproximate what a proberly 650/532/473(/405) coated PCAOM would cost?

Other way could be eventually polarize the lasers and then modulate by lcd layer...

To the mirrors: What about rotating polygon mirrors

 

[diachi]

I have one of those AOMs, and the only problem with that idea is that those are coated for red HeNe wavelengths. The losses with green or blue is too high..

With a properly coated PCAOM you can combine the beams first. That would be the only practical way to build this kind of project. You wouldn't necessarily need three AOMs. One of the main functions of PCAOMs in laser show use is to control color intensity as you already know, so that would definitely be the way to go here.

It's not the coatings that's the problem, the problem is the driver. The driver creates a wave in the crystal which changes the crystals properties at certain wavelengths, if the driver is at an incorrect frequency then it can't modulate at that wavelength.

-Adam

 

[diachi]

Ack. can you aproximate what a proberly 650/532/473(/405) coated PCAOM would cost?

Other way could be eventually polarize the lasers and then modulate by lcd layer...

To the mirrors: What about rotating polygon mirrors

$1600 - 5000 new