Is there any flat panel technology that runes like a CRT TV?

Nope.
The standard on TVs now is 16:9 progressive scan and high definition.
A modern plasma is closest to a CRT's picture quality but with a larger screen, thinner and lighter.
Don't miss the big bulky CRTs - they were too heavy to move.

Every flat panel sold in the USA is capable of displaying an NTSC analog TV image, either from a tuner, VCR, DVD player, or older gaming console. The image will be "pillarboxed" on the 16:9 screen with vertical black bars on the sides.

In general, this works well. However, if your intent is to use an old gaming console, there are limitations. Games that involve a controller, exercise pad, and most other devices will work. But games that involve a photo-electric "gun" such as the NES "Zapper" will not work:



...because the pointing technology is dependant upon the photocell in the gun detecting the light from the screen, and measuring the timing against the video signal. AFAIK none of the current video displays are compatible with the older shooter games.

Some things are better left in a museum.

Yes, its called SED, something like CRT. Unfortunately the Pioneer Kuro killed SED and then died itself.

The image from a Plasma TV is nothing like a CRT television. The only similarity is that they are both emissive displays that utilise phosphors. The resulting image bears no resemblance to a CRT.


SED was much more like a Plasma display than a CRT, it just used a different method to light the cells. Just like Plasma displays, they used pulse width modulation to control brightness, rather than having analogue control by changing the voltage.

This is one of the biggest issues with Plasma, DLP and other display technologies.



FED SED was like Plasma, where brightness was controlled temporally, rather than by actually reducing the light output of the display as with the CRT, LCD and "theater" examples, though CRT actually reduced both light output and length of exposure, which is something no other display seems to have today.

Are you talking about Scan Velocity Modulation here? My ancient Pioneer Elite has that feature, but my understanding was that it was a Bad Thing and I never enabled it. Or is length of exposure reduced some other way?

It's really helpful to us if you proofread your copy before sending it up here to the threads. I think you mean SED? I was about to run all over the net thinking there was some new technology I was not aware of...

b

Length of exposure has nothing to do with SVM. Length of exposure has to do with the amount of time a mirror in a DLP stays in its bright/reflective position vs. how long it stays in its black/non-reflective position. There is no in between, that mirror is either reflecting or not reflecting, depending on what its told by its microprocessor to do.


Some level of SVM is good, too much or too little is bad. Too much gives false edging to all vertical lines, too little makes the whole pic just too soft.

The trick is to find just the right amount. That's what we do when we do the CraigR anti-ringing mod, for eliminating too much false edging without compromising the picture's crispness. It's a fine tuning process.

Contrary to the advice on some test discs I have tuned into, you don't just eliminate SVM or Sharpness or Detail, each of them does have its own value when set properly. Sometimes it's all the way down sometimes it's all the way up. Sometimes it's somewhere in between. You find the best of both worlds for your particular set.

On a Pioneer Elite or non-Elite, in Service Mode I goose the Detail up to almost full - usually 120-125 out of a potential 127. Then I dial down the service menu Sharpness to whatever will not allow too much edge ringing. I usually keep the SVM in User mode at its midpoint, or just let it default to its optimum User setting by being in service mode at all, which defaults all the User menu settings automatically.

The object of my calibrations is not Sharpness, which has gotten itself a really bad name in our industry. It's crispness.

b

Refrigerators are too heavy to move. CRTs have never been hard to move. They have always been on wheels except the trickle of table versions.

Moving CRT RPTVs, big as they are, is easy. Certainly not a reason to avoid them, esp. when needing to move them does not happen often at all.

b

Actually, FED is a similar display technology to SED that AUO is apparently still researching. That was an unintended typo however.

FED looks interesting, tho the specs on their prototype max out at 20,000:1 on contrast ratio, falling way behind CRT.

That they compare themselves to CRT is telling, tho. It reinforces my stance that fully dialed in CRT is still the leader in HD display technology.

If you want to find out more about this, go to the AVS thread "Don't Dump Your CRT RPTV!", a thread I started more than 5 years ago and that is still going strong, with currently more than 350 pages.

http://www.avsforum.com/avs-vb/showt...95922&page=358

To see master dialed-in CRT projectors in action and the pictures they are capable of displaying, visit Cliff's (Overclkr) "Screenshot War!!!!!!!!" thread, now at 177 pages -

http://www.avsforum.com/avs-vb/showt...00831&page=177

Mr Bob

Broadcast monitors (the best CRTs ever made) are 10,000:1 when set up correctly. (100cd/m² white, 0.01cd/m² black)

If you adjust a CRT so that the black level is below that, you quickly move gamma away from reference level, losing shadow detail and oversaturating the image. (though the low ANSI contrast can "lift" some of that shadow detail in brighter scenes)
You are also reducing the bias voltage below the level required to keep the tube at the proper operating level, which has the effect of significantly slowing the response time of the tube, resulting in ghosting of the image in dark scenes.

Even if you use an external LUT box to correct for the skewed gamma, you are then likely to be introducing banding into the image because most of your corrections will be at the low end of the scale (it's far easier and less noticeable to make corrections near white) and it still doesn't fix the ghosting. ("phosphor lag")


It absolutely is in many respects, though they lack the sharpness and ANSI contrast of flat panel displays, and the phosphors used with many of them could not cover the BT.709 gamut.

The closest thing to a flat panel CRT replacement that's been shown so far has been Sony's Crystal LED display, as it's a scanning display and the image is right on the glass. (unlike OLED where the micro-cavity structure limits viewing angles)

The best alternative available today, is a full array local-dimming LED backlit LCD. To start with, they're available in much larger sizes than direct-view CRTs. They cover the BT.709 gamut, backlight scanning has just about eliminated any motion handling issues, ANSI contrast is higher than that of CRT ("blooming" has less of an impact on the image) and they can turn the LEDs off for a true fade-to-black without the compromises you have to make to get a CRT to do that. They are capable of good gradation without the use of dithering as PDP/DLP uses. As a fixed-pixel device, they're far sharper than any CRT. They have enough brightness to be used in a brightly lit room if desired. They do have poor viewing angles however, and while they're better than other flat panels, nothing has come close to the smooth gradation of a CRT yet.

Scanning laser projectors have potential in the projection space. SXRD/DiLA projectors have poor motion handling and sharpness but good contrast, and DLP has the "rainbow effect", dithering, and poor on-off contrast. (but they're sharp, and have great ANSI contrast)


A lot of the screenshots there are showing exactly what I was talking aboutskewed gamma causing a darkening of the image and oversaturation. (skintones in particular look rather bad, making people look sunburnt) Most of the screenshots also exhibit a "misty" look to them caused by low ANSI contrast, and the images seem rather soft.

The IvsT charts (which I like BTW) are incorrect for the Plasma. They should resemble the CRT but be elongated (and reversed depending on model year)

^ +1 thanks xrox I thought it looked wrong but can't be certain enough to point it out

Chronoptimist -

Very telling article, thanks for the input.

The Contrast Ratio I was talking about must have had a different measuring method, because it was the triple stack of Cliff's in Indiana - Overclkr at the Screenshot War thread.

The measured CR on that stack was more than 525,000:1 and was obtained by measuring the actual light output at totally nil signal - virtually black screen - vs. totally white, all measured on the same screen. All 3 pj's aimed at the same screen, all pix completely superimposed on top of each other, this was not a blend type of picture. The foot-lamberts level of the brightest to the blackest, measured by a very sophisticated color analyzer, was the measurement sys involved.

Cliff also uses a Moome gamma bump, which enables the blacks to stay black while the shadow detail is raised to a noticeably pronounced - and as such much more highly visible - state. It leaves the whites primarily alone, focusing chiefly on the darks and black. The shadow detail is as such allowed to be much more visible while keeping the blacks true black. There is no "black crush" when using a Moome device, your eyes don't get starved for shadow detail when the shadow areas are near black, as is common on most of the phosphor-based tech out there, including CRT.

The end result is mind-boggling, even as a screenshot, as several were sent up and even as screenshots showed the enhanced contrast ratio that sys was capable of.

The sys has absolutely no problems with shadow detail or crisp, transparent, inky blacks, the best I have seen next to the million:1 CR of OLED, which is the ultimate I have seen yet.

As such, since they used a very straightforward methodology, I would surmise that each G90 CRT projector used puts out around 135,000:1 contrast ratio.

b

Yes, that's true, and technically you would also have different responses listed for R/G/B overlaid, but I think it's generally a good diagram to explain how the different technologies operateat least on a basic level.

While PDPs do show the effects of being phosphor-based, the main principle is that they're driven at full brightness and different shades are created by the length of exposure, rather than varying the light output from the panel as a CRT does. (which also happens to reduce the length of exposure)

And I just noticed that I forgot to source the image.


Yes, as I said, you can use a LUT box (or in this case a Moome box/card) and get a very high contrast ratio (especially if you use a stack to boost the light output) but it still negatively impacts the image in dark scenes as a result of setting the bias voltage below the level required to keep the tube at the correct operating voltage.

While not a stack, I've done the same thing in the past (it looks great if you can tolerate the slow response) until finally having to abandon CRT as they got older, less reliable, and harder to maintain. It's tougher when you're outside the US and in a market where RPTVs never took on, projection is rare (really only picking up with the introduction of more compact digital projector) and CRTs were abandoned within a couple of years of flat panels being introducedwhen sets like the XBR960 were being introduced in USA, you could barely buy a CRT here, let alone an HD tube of that quality or a projector. (even second-hand)

Thanks for enlightening me on plasma, I was not aware that time exposure was incorporated in its design, like it is on DLP. I thought plasma and CRT used the same amount-of-light methodology. After all phosphor has a pretty stock decay rate, am surprised to hear that that decay rate is being manipulated on plasma while not on CRT, thought it was built-in and thus unchangeable.




I must disagree with you about the biasing voltage, tho.

All use CRTs use a similar methodology for setting the ideal gain of the biasing voltage for ideal darks/blacks, Mit RPTVs and NEC ceiling pjs use a specific voltage at each CRT test point, each gun typically exactly the same as the other 2. That established, you then go to the Cutoff registers in your service menu to get the correct shadow detail and balance for grayscale in your darks, and the Drives interact with the Cutoffs to establish the correct grayscale in the bright areas, ultimately resulting in correct gray at all relevant light levels - ie everything 80IRE and below being smooth and the correct color of gray.

Then you go to your Moome device and you get the compression that results in the Gamma bump - which enhances shadow details while leaving the ultra blacks completely alone. No further adjusting is done, the box is simply added and you adjust your Brightness/Black Level to suit.

At no time does that deeply internal biasing voltage ever change again, after setting your Screen controls for the proper voltage biasing at the beginning. It stays exactly where it was originally put, and the picture simply becomes sinfully delicious.



BTW, what does LUT mean?

b

A simplified explanation is that CRT used an electron gun to "activate" the phosphors, so depending on the voltage used (strength of the electron gun) the brighter it would be.

With Plasmas, you can essentially only turn a cell on or off, with no way of varying whether it's at full brightness, half brightness etc, so the only way to create dimmer shades is by reducing the length of exposure.



LUT is "Look-Up Table" and so what basically happens there is that the box processes the image by having a table of input values, and mapping them to output values.

So you might have: Input: 10% Grey.
But on your display, sending a 10% grey image might be darker than it is supposed to be, so you might set the output to 15% grey, raising the brightness of it to the correct level.

It's similar to some of those "gamma boxes" out there, but rather than only having a single "gamma" value to control, you can have complete RGB control of every single point from black to white, letting you calibrate any display to have a perfect greyscale and gamma response. (or as good as it allows)

A 10-bit LUT box, assuming it exposes the necessary controls, could give you 1024-point greyscale & gamma control for example. (it may also incorporate a color management system as well for gamut)

Now 1024-points is complete overkill of course, but sometimes the 2-point or 11-point controls that most displays offer just aren't enough, especially if you're doing something like reducing the brightness control on a CRT far below the level it's supposed to operate at, and want every level down to black being visible and distinct, while retaining "zero" black level.

Cool. Thx!

b

RG phosphor decay rates on PDP are significantly longer than on CRT (~5-10x IIRC) and are not manipulated AFAIK.

Like Chronoptimist has shown, CRT modulates light intensity in a fixed time period while PDP modulates light intensity dependent of time.

However, PDP does not use pure PWM. It uses subfields spaced across 1 frame period. This produces an IvsT plot that resembles a ramp. This is the source of PDP flicker. Not PWM which most blame incorrectly.