TCL Dual Cell LCD combined with MEMS Laser projection for the backlight

[blurfreeCRTGimp]

Hello, I am new to the forums, and am just putting forward an idea that I have not seen put forward before.

So, TCL has their new dual cell LCD TV sets where one panel is used for grey scale and another panel is used for color. I got to thinking, wouldn't it kill two birds with one stone to use a MEMS laser projection system to make a grey scale + backlight (like the ShowWX projector) combined with a 240hz LCD layer for the color channels?

Since MEMS projectors have focus free projection with persistence better than CRT, doesn't it theoretically make sense to create a panel with a mems laser backlight layer combined with IPS for color?

You would get low persistence/full array local dimming (because of the laser scanning technology of MEMS) acting as your grey scale layer plus the color and viewing angle of an IPS LCD. I'm not an engineer so I am not sure this would be practical (due to MEMS nits limitation) but it seems like a route to get blur free and decent color using LCD.

[Chief Blur Buster]

That's a clever left field idea! Combining MEMS and LCD is theoretically doable, although can it be done with enough benefits for cheap enough, in panels thin enough...?

Currently (for now) -- I suspect -- engineering wise -- a simpler 10,000 pixel LED FALD or even 100,000 pixel FALD is much cheaper to manufacture.

MicroLED is about to be conceptualized as the FALD becoming the display itself, at millions of pixels. So a good interim step is to upgrade FALD to something high resolution enough to be halo-free.

Even CRT phosphor illumination often have glow scatter around the electron gun dot, so one would use a sufficiently high-resolution FALD (less than MicroLED, more than today's FALD) to be more halo-free than CRT illumination.

As of 2020, today's LED ribbons are now machine manufactured (under $10 for 300 LED 5 meter if in quantity on Alibaba), and today's 32x32 and 64x64 JumboTron modules are machine-manufactured so are cheap (~$200-$500 per square meter of JumboTron in China). Once FALD MicroLED sheets get machine manufactured, it will dramatically lower the cost of FALD by the mid 2020s, as an interim step before direct-view MicroLED displays -- I would think that 10,000 LED FALD sheets could theoretically hit only a few dollars.

We don't want perfect to be the enemy of "better than CRT", so an high resolution MicroLED FALD would be a good interim between LCD and direct-view MicroLED.

Now, one issue is that dual-cell LCDs make FALDs redundant, but you've got kind of a persistence problem that can only be solved by strobed backlights or scanning FALD backlights (or ultrahigh refresh rates if keeping sample-and-hold).

Regardless of dual-cell LCDs or otherwise, one new idea is that FALDs could perhaps even recycle module design that would normally be used with a JumboTron, and use it as the FALD backlight (with minor optics modifications), there may be some clever cost-cutting engineering moves that may now be possible.

[blurfreeCRTGimp]

Using MEMS would do more to benefit persistence and ULMB than it would using it as a grey scale layer, wouldn't it?

I was just thinking of it as a grey scale layer as an added bonus.

Since MEMS has a fast line by line scanning method of drawing an image similar to CRT for blur free images I thought it would be a good combination with a high HZ sample and hold display.

It seems to me (correct me if I am wrong) that using MEMS you could get ULMB on a sample and hold display without the need for a backlight strobe since the persistence of MEMS (which would be providing the backlight) is basically instant? The strobing would not be nearly as harsh on the eyes as it is on a conventional backlight if I'm not mistaken.

It would surely be ridiculously expensive lol.

Do you know of any MEMS projectors still on sale? I cant even find any,

[elexor]

Wish laser projectors kept progressing. I tested one of those showwx laser projectors vga model it has framestutter at 60hz for some reason the only way i could get rid of the stutter was running it at 62hz which is useless. the motion clarity was awesome tho.

input lag was +1 frame more then a crt. so it must be doing some kind of buffering.

[elexor]

SONY MP-CL1A is the one im interested in you can still get them but don't think they have been manufactured for a long time.

I think they could be useful for blurfree 240p gaming provided it has no input lag and does not stutter at various refreshrates.

They have some major downsides
- laser speckling
- low brightness (only really useable in a very dark room)
- non perfect geometry
- lower resolutions and not as sharp.

Has anyone here tested one for latency and stuttering?

[Chief Blur Buster]

Wish laser projectors kept progressing. I tested one of those showwx laser projectors vga model it has framestutter at 60hz for some reason the only way i could get rid of the stutter was running it at 62hz which is useless. the motion clarity was awesome tho.

I think that model used a bounce-scan. Scanning downwards every other refresh cycle, scanning upwards every other refresh cycle. That creates per-pixel stutter, since the refreshtimes between pixels vary differently per pixel line, creating stutter caused by the unconventional laser refreshing algorithm.

If you watch www.testufo.com/scanskew on one of those lasers, you will see that TestUFO test go beserk. Very crazy.

www.testufo.com/scanskew tilts normally in one direction on a 60Hz-only panel (DELL monitor, HP monitor, Apple iPad in certain rotations, etc). But on the bounce-scan laser, it looks like a flickering jumpman jack bouncing sideways as it becomes an "X" leaping sideways until it merges into a single line at the ends of the sinewave bounce, because it's two superimposed tilts (opposite scanskews every other refresh cycle).

The correct way to refresh a laser is the same way as a CRT; exact same raster scan pattern, every refresh -- like a book, like a calendar -- left-to-right, top to bottom -- and with screern scanout preferably in sync with signal scanout.
See High Speed Videos of Screen Refreshing

[elexor]

Do you know if the SONY MP-CL1A refreshes correctly? I wanna buy one but don't want to risk buying it if it's not going to be stutter free.
or are there any other mems projectors you know about? I think they look really nice with upscaled 240p content.

[elexor]

I tried the scanskew test it looks normal other then abit of skew. It really seems like it's just a mismatch between refreshrate input and what the display is actually refreshing at 62hz clears up the stutter. but if i change to 60hz it's a stutterfest.

[Chief Blur Buster]

I tried the scanskew test it looks normal other then abit of skew. It really seems like it's just a mismatch between refreshrate input and what the display is actually refreshing at 62hz clears up the stutter. but if i change to 60hz it's a stutterfest.

Refresh rate sync can be the issue too -- the laser scanning independently of the signal refresh.

It might not be a bounce-scan laser but a native refresh rate out of sync from signal refresh rate. Photographing www.testufo.com/frameskipping will reveal probable 2 bright squares per second for a scan conversion 62Hz-to-60Hz.

That can be an issue, you have to change the PC refresh rate to match the laser refresh rate.

[elexor]

thanks for the reply it's abit unfortunate most content i want to use with it is in the 60fps range.
Are all mems projectors fixed scanrate?