LPD: Laser Phosphor Display - Successor to CRT?

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Re: LPD: Laser Phosphor Display - Successor to CRT?

Post by Chief Blur Buster » 30 Oct 2020, 20:09

Have any of you access to an Oculus Quest 2?

It's one of the lowest-MPRT LCDs on the market (~0.3ms MPRT). The in-headset web browser is fully compatible with TestUFO. Also, additionally, it can run a Virtual Desktop at framerate=Hz.

It's one of the best CRT-motion-clarity LCDs that I have ever seen -- zero detectable strobe crosstalk, while retaining most of OLED color quality. The blacks are not 100% perfect but other than that, but it's among one of the best CRT-emulating LCDs I've seen so far. If you switch the Quest to 60 Hz, and then run MAME HLSL in a Virtual Desktop inside a Quest 2 with the most accurate CRT filters, it actually kind of looks like a real CRT tube. You can switch the Quest 2 between 60 Hz and 72 Hz.

The Quest 2 has approximately 0.3ms MPRT, no detectable motion blur -- about 1/6th the motion blur of original Oculus Rift headset. The Quest 2 is unusual in that it has a 60 Hz refresh rate option, perfect for running emulators, something that the other LCD VR headsets do not have -- which means you can combine the cake ingredients, have cake, and eat it too.

VR headset-based emulation of retro tubes is a viable route of reproducing CRT clarity too, by putting a virtual CRT tube on your desktop (quality-wise speaking). The resolution of the Quest 2 is sufficiently high enough to use the Oculus Quest 2 as a high-definition computer monitor that's not actually in front of you.

There is less motion blur in an Oculus Quest 2 than on a CRT tube. There is a smidge of compression artifacts when streaming fast-motion PC Desktop to the VR headset, but you can directly stream and play 60fps video directly in YouTube application built into the headset, at 60Hz, and it looks like it has exactly the same display motion blur as a CRT tube -- fast-shutter POV videos on a floating bigscreen in front of you in virtual reality.
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Re: LPD: Laser Phosphor Display - Successor to CRT?

Post by blurfreeCRTGimp » 31 Oct 2020, 02:16

Hey Chief, I don't have the quest 2, but I do love using the rift CV1 with emulation.

Lucky for me, I have my little 13 inch CRT still, but I don't know how long it will live.

Do you know what happened with Carmack's experiments with deep interlacing a display? (where 60hz could be 120 fields per second?)

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Re: LPD: Laser Phosphor Display - Successor to CRT?

Post by Chief Blur Buster » 31 Oct 2020, 19:51

blurfreeCRTGimp wrote:
31 Oct 2020, 02:16
Hey Chief, I don't have the quest 2, but I do love using the rift CV1 with emulation.
Were you able to get CV1 to a 60.000Hz refresh rate?

I have posted the 60Hz refresh rate Oculus Quest 2 instructions in the Good News Everyone: 60Hz Single Strobe Options thread.
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Re: LPD: Laser Phosphor Display - Successor to CRT?

Post by blurfreeCRTGimp » 31 Oct 2020, 23:04

I do not own virtual desktop, so I don't know a way to change frame rate on the OG Rift or enable single strobe. I'm sure it would look awesome with a good CRT shader. I usually use big screen with Retroarch and CRT shader, but its just running at 90hz

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Re: LPD: Laser Phosphor Display - Successor to CRT?

Post by Chief Blur Buster » 01 Nov 2020, 12:26

blurfreeCRTGimp wrote:
31 Oct 2020, 23:04
I do not own virtual desktop, so I don't know a way to change frame rate on the OG Rift or enable single strobe. I'm sure it would look awesome with a good CRT shader. I usually use big screen with Retroarch and CRT shader, but its just running at 90hz
BigScreen and RetroArch works fine on Quest 2. I find Quest 2 is superior to my original Rift CV1 in nearly all departments, with the sole exeption of black levels (Which is a big boohoo for Half Life Alyx which has lots of dark scenes, or arcade emulation with lots of black background such as Ms. Pac Man or Donkey Kong).

However, bright scenery is better quality in Quest 2 and so many other aspects improved that even an LCD can be made to emulate a CRT better than an OLED can, given the right variables and technology. The only thing is milky greys of non-FALD LCDs. I hope future LCD VR is MicroLED FALD backlit for deeper blacks in VR.

The new VR LCDs currently used by Quest 2 is the lowest-crosstalk LCD I have ever seen: Zero, even for top/center/bottom. It's absolutely stunning how strobe crosstalk has been zeroed-out even in TestUFO Crosstalk test, even for top edge and bottom edge too. Not even LightBoost can touch that, and somehow Quest 2 pulls it off with no color-quality compromises (except imperfect LCD blacks).

And kudos to the engineers for the in-headset Chromium browser being 100% fully TestUFO compatible, even supporting TestUFO fullscreen mode in virtual reality. It's quite something to be standing virtually (in VR) in front of an IMAX sized TestUFO, seeing zero strobe crosstalk.

(Focussing on Oculus technicals only; no comment on politics or Facebook -- this is just technical geeking-out)
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Re: LPD: Laser Phosphor Display - Successor to CRT?

Post by blurfreeCRTGimp » 01 Nov 2020, 15:15

I actually think dual cell LCD is going to be the best bet for getting OLED black levels out of LCD. FALD back lights are awesome, but having a separate LCD layer for Chroma and another for Luma seems to work amazingly well. You could probably put a FALD backlight in a dual cell screen and make it even better.

I think that a back light driven by RGB lasers going down the length of panel would get us to that insane low persistence of .01 ms without any loss of brightness and with no flicker without needing insane FPS.

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Re: LPD: Laser Phosphor Display - Successor to CRT?

Post by Chief Blur Buster » 03 Nov 2020, 16:12

blurfreeCRTGimp wrote:
01 Nov 2020, 15:15
I actually think dual cell LCD is going to be the best bet for getting OLED black levels out of LCD. FALD back lights are awesome, but having a separate LCD layer for Chroma and another for Luma seems to work amazingly well. You could probably put a FALD backlight in a dual cell screen and make it even better.

I think that a back light driven by RGB lasers going down the length of panel would get us to that insane low persistence of .01 ms without any loss of brightness and with no flicker without needing insane FPS.
Dual-cell LCDs are a great option for increased contrast ratios. They do make strobing / scanning a bit more difficult because you're now weak-linked by the two different GtG's of the two LCD layers. But as long as the GtG pixel response is sufficiently fast, it can be done.

The rheoretical question for engineering is which will be cheaper to achieve high quality scanned low-persistence FALD (Full Array Local Dimming) that has unnoticeable blooming and OLED-quality blacks:
1. A dual-layer LCD alone (use luma LCD layer as low-persistence scanning "backlight")
2. A dual-layer LCD with a basic backlight array (for low persistence scanning purposes)
3. A single-layer LCD with a high-resolution MiniLED FALD (that is also a scanning backlight).

The last item may potentially be easier to achieve low-persistence because you're dealing with only one GtG but the extra cost of a high-resolution (50,000+ LED count) locally dimmed MiniLED backlight needs to be compared against the cost of a dual-layer LCD. It is wholly possible that one or the other cost horse may win by the end of the decade.
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Re: LPD: Laser Phosphor Display - Successor to CRT?

Post by blurfreeCRTGimp » 11 Dec 2020, 03:54

Hey chief, I was just wondering something. This is going to sound heretical and probably just really stupid, but let me know what you think.

What if you were to add a high quality scanning FALD backlight to an OLED? OLED suffers from burn in and image retention largely because of the voltage required to drive them brightly. When you run them with aggressive BFI you get great motion clarity, and the OLED lasts longer while being less prone to burn in. A really awesome scanning backlight could mitigate all brightness loss from BFI, and contrast ratios would still be amazing due to scanning the backlight.

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Re: LPD: Laser Phosphor Display - Successor to CRT?

Post by Chief Blur Buster » 11 Dec 2020, 19:54

'That's a non-sequitur question -- OLEDs doesn't work with backlights.

OLED is THE metaphorical backlight itself except it's a direct-view. A rolling-scan BFI OLED is the same pixel flash algorithm as an LCD's scanning backlight. A scanning backlight is a rolling-scan flash, just like a rolling-scan BFI on OLED. An OLED itself can also be scanning light source, just like a backlight.

There are also tests in OLED-backlit LCDs too (OLEDs can also double as a FALD backlight for LCD), and OLED can be a scanning backlight for an LCD. But LED backlights lasts longer than OLED backlights for LCD panels.

LED and OLED can be direct-view (like LG OLED TVs and Samsung WALL MicroLED TVs) or the backlight source for an LCD (LED-backlight LCD, as well as OLED-backlight LCD). Such backlights can be FALD or non-FALD, whether it be a FALD LED backlight LCD -- or a FALD OLED backlight LCD.

Confused? :D (Hope not)
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Re: LPD: Laser Phosphor Display - Successor to CRT?

Post by blurfreeCRTGimp » 17 Jan 2021, 16:23

If you used an OLED as a backlight that was monochrome, but then used an LCD for a color shutter couldn't you get much better response times for GTG and color transitions? Since OLED has like .2ms transition time from White to black, if you used an LCD as a color shutter like an old LCCS CRT?

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