LPD: Laser Phosphor Display - Successor to CRT?

[ChaosCloud]

(a couple years back I posted a thread at BlurBusters about this. Posting here since I'm interested in HardForum's thoughts.)

LPD is a rear projection display using a scanning laser (ultraviolet) which excites coloured phosphors on the screen - Very similar principle to CRT (which steers an electron beam instead.).

There is even a company, Prysm, selling these displays right now, albeit as large format video walls for the commercial market.
They are able to achieve 6864 x 1872 @ 360 Hz - if it's field rate that equals 180 Hz refresh
(using modules of 624 x 468 pixels, 22" diagonal size)




I don't see why this tech could not be scaled down to make enthusiast gaming displays. The Sony MP-CL1 projector fits in a pocket and projects 1920x720 @ 60Hz using RGB laser scanning.

The main disadvantage of CRT was size and weight. LPD has no reason to be much heavier than a typical LCD, and the size could be reduced compared to CRT by using mirrors to reflect the beam (see attached image comparing late 2000s RPTVs proportions with a modern gaming monitor)

LPD has much lower power consumption than CRT, possibly even lower than modern LCD.

LPD also has much better contrast than LCD.

It seems like the holy grail of display tech, at least until 1000Hz/1000fps TFT displays becomes feasible. Thoughts?

Recently I've been thinking:
Using a UV laser to excite blue phosphor under a Quantum Dot layer for Green and Red would probably be ideal.
UV is preferable to blue or RGB laser since the wavelength is smaller = higher potential resolution.
Quantum dot has proven practical with the latest QD-OLED displays. It allows for wide colour gamut.
Using only a single phosphor colour means no issues with varying phosphor decay times as was seen in plasma displays.

 

[Nobu]

They also have plasma-ish size displays on ebay, open box for about $700, iirc.

 

[toast0]

Saw those in that wacky CRT thread earlier. These look cool, but I dunno. If you're in LA, there's a local pick up "parts only" listing on ebay with 9 panels for $95 each, says they turn on but display unknown (which seems reasonable because they're not selling a display processor).

Raster scanning a laser at 180 frames a second is gonna be expensive, and tricky to modulate the laser, so I don't know if it's likely to scale up to bigger displays without tiling. If you're attached to the scanning of a CRT, I don't know if you get the same effect with scanning per tile. If you're doing tiling anyway, microled seems to have about the same DPI as these tiles, and no moving parts.

 

[ChaosCloud]

Saw those in that wacky CRT thread earlier. These look cool, but I dunno. If you're in LA, there's a local pick up "parts only" listing on ebay with 9 panels for $95 each, says they turn on but display unknown (which seems reasonable because they're not selling a display processor).

Raster scanning a laser at 180 frames a second is gonna be expensive, and tricky to modulate the laser, so I don't know if it's likely to scale up to bigger displays without tiling. If you're attached to the scanning of a CRT, I don't know if you get the same effect with scanning per tile. If you're doing tiling anyway, microled seems to have about the same DPI as these tiles, and no moving parts.

Hah, I never checked Ebay for this. Cool to see the actual units

On the laser pico projectors they use a tilting micromirror to steer the beam in a raster pattern. It seems pretty straight-forward... I think the tricky part is using internal reflection to take up the throw distance, since the mirror is limited in how far it can tilt, and nobody wants a cabinet that would be a few feet deep.

Sony's MP-CL1 was scanning 1920x720 @ 60 Hz. It's a 7 year old device now. I'm guessing there has been some advancement in micromirror tech since then. But if not, then yes, tiling of separate rasters could be used with negligible impact on motion clarity, though aligning the tiles could be a challenging task!

For starters, if we can get 1920x1080 @ 120 Hz, it would already blow away every other gaming monitor currently on the market in terms of motion clarity, even 360 Hz ones. Plus, with the lower FPS requirement, people could actually run new games on the highest graphics settings.

With microLED it's either a sample and hold display = very poor motion clarity unless getting up to crazy high refresh and frame rates ~600-1000. Out of reach for hardware and software at the moment. Burn-in is still a concern.

If it's using scanning/strobing like modern gaming monitors can do, motion clarity is improved, but still inferior to raster scanning. (My audio player has a small OLED display that works like this. Better than sample and hold, but produces artifacts when moving eyes quickly.) It is susceptible to burn-in.

If microLED is able to do line-by-line raster type scanning it can match CRT motion clarity, but without phosphor decay it will be a much harsher flicker than CRT or Plasma which will cause eyestrain for some people. Also, driving the single line at the extreme brightness required for raster scanning will make the display very susceptible to image retention / burn-in.

With laser scanning, burn-in or image retention should not be a concern, like with the last-gen CRT monitors. "Burn-out" is more of a concern - when the laser finally burns out after many hours of use.