Ahigh wrote:The ultimate display is going to appear to the eye to be more like a CRT with a top-to-bottom scan process. In addition, the waveform of the brightness of the lit pixel should also fade leaving a faint trail in the retina. The eye's sensitivity to light is not linear with brightness. It is for this reason that the light should fall off with something besides what approximates a trailing edge of a on-to-off digital transition. This falloff is critical to having an improved sense of brightness without strictly being only width or only height as described by Mark. An idealized 4K LCD display will light exactly one row of pixels at a time. This is ideal in order to reduce latency as well when the input signal from the computer is fast enough to scan the LCD elements in real-time from the signal of the display's output.
I think rolling-scan OLED's are the easiest way to achieve CRT emulation.
High speed video of Sony OLED rolling scan
This is easier to do with OLED's than LCD's. It does not simulate the decay effect, but it demonstrates the rest of the concept.
Brighten the OLED elements, shorten the rolling scan (OFF pass closely chasing the ON pass), and you'll get pretty close. Adding the decay effect to an active matrix OLED is a lot more challenging, but probably achievable via either row voltage manipulation or FADE refresh passes (scan line refreshes with darkened pixels) chasing after the ON scan pass.
At stroberates over 100Hz, I personally don't care about decay (and it becomes an engineering complication with not much risk-reward), but I realize it can certainly soften the flicker and make it more tolerable to some people. Especially if you are trying to do 60Hz and emulation. At stroberates of 240Hz (e.g. tomorrow's low-persistence 240Hz displays) it might actually become more of a moot factor.
That said -- for the word "
ultimate display" -- my opinion of the ultimate display is actually not a CRT, but a flickerfree framerateless (continuous motion display, a concept that is extremely hard to engineer) or an ultra-high-framerate display (>1000fps@1000Hz). CRT clarity without CRT flicker (no flicker even under high speed camera), would be a big engineering challenge. Basically, achieving low persistence without the use of strobing, decay or light modulation. Which is an engineering challenge. Unfortunately, doing low persistence with no strobing/flicker, requires ultra high framerates at the moment. One bandwidth-lowering shortcut to this, may be an eye-tracked display that refresh faster only where the eyes are currently pointing at. Another advantage of ultrahigh refresh rates is less stroboscopic effects (less mouse dropping effect, less wagonwheel effect). Scientifically, you would need a flickerfree display of approximately 700fps@700Hz (1/700sec = 1.4ms) in order to have a display of 1.4ms persistence, without needing flicker/decay/strobing, the same persistence as LightBoost=10%.
However, the "
ultimate CRT replacement", probably will be a low-persistence rolling-scan OLED with elements bright enough to simulate the insane brightness of CRT (thousands of candelas per square meter) during the briefness of illumination. As much an engineering challenge OLED's are, I think that's currently the easier ultimate CRT replacement, over the long term. I feel gaming monitor manufacturers should consider designing a rolling-scan OLED, with an adjustable persistence (adjustable chase distance between OFF scan behind ON scan), and a goal of 2ms persistence, preferably 1ms (And eventually 0.5ms, since I can easily tell apart 1ms persistence and 2ms persistence during
http://www.testufo.com/photo motion tests). And they easily go flickerfree (sample-and-hold) via a button or flick of a switch, for the flickerfree static text reading experience, for those who prefers that. Also, OLED are technologically very GSYNC friendly (at least in sample-and-hold mode), and even it should be possible to design a dynamic rolling scan that permits low-persistence GSYNC capability (variable-rate strobing), though it may have to execute repeat refreshes at a floor (e.g. 60Hz or 75Hz) to prevent obnoxious flicker.
lol