A look inside a LASER digital cinema projector

[James Gardiner]

Hello Everyone,
I made a video about a Laser digital cinema projector. Based on an old projector that was broken. I took out the light engine and light source, then took video of many parts we typically never get to see in action.

I hope you enjoy it.

James

[Steve Guttag]

See now, the sick sense of humor in me would have had you start the video with an eye patch warning to never look into the projector when it is on.

I believe that on DCinema machines where two blue laser systems are used...one for blue and the other to pass through a yellow phosphor wheel, the purpose of the frosted wheel for the blue light is to have a matched light with that which goes through the yellow phosphor wheel so that they combine properly when heading into the light pipe. Blue is rarely a source of speckle as people can't really focus on it to begin with.

With respect to speckle, I see more machines using multiple primary wavelengths within the red and green lasers as a means of lessening it.

Where I see phosphor wheels being used are on lower-end projectors to avoid the expensive green laser (pretty much any Sharp) and in double-blue lasers (bottom tier 2K machines). The other place I'm starting to see them is in addition to RGB lasers in order to work on better color metamerics, like Christie's RGBH projectors.

There is another thread where I posted screen shots of a spectroradiometer with various projectors showing the multi-spiked Red and Green and those with a phosphor wheel (particularly for green) where you can really see how imprecise the color is. However, I agree that those systems with phosphor wheels, speckle is a non-issue. Lowering the screen gain to 1.0 (matte-white) will also help.

https://ft-forum.com/ft/vbb/forum/main-forum/57674-experience-with-color-calibration-between-lamps-and-lasers-and-their-matching?p=57809#post57809

[Caleb Williams]

Seeing inside the laser module was a treat! I've also been wondering how the speckle mitigation system physically looked, so thank you for that as well!

I'd also be interested in your process for software development, since the speed at which you release new software is impressive

[Ryan Gallagher]

The actual construction and arrangement of the diodes (and their mirrors) in the laser module was the most interesting part I had no prior awareness of. Thanks!