Author Topic: An expensive TV is a poor investment, and people spend FAR too much on them  (Read 21864 times)

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Offline bw2341

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #125 on: February 08, 2022, 03:38:32 am »
There have been LCDs with subpixels beyond RGB, notably Sharp’s Quattron which added yellow. Single-chip DLP projectors all use multicolor filter wheels, including very high end ones.

I'm going to have to agree with BrianHG on this one. White channels are a clever workaround to make up for deficiencies at the expense of picture quality. Pure RGB direct emission is the way to go.

Sharp’s Quattron was a short lived product. High brightness business grade portable DLP projectors need white on the filter wheel, but high end home theatre DLPs have moved to RGB LEDs or laser light sources. To achieve the highest brightness and picture quality, movie theatre DLPs have three DLP chips and RGB lasers.

A white channel reduces the colour gamut at high picture levels. Imagine that the white, red, green and blue channels can reach 60% of the desired maximum brightness. Typical medium brightness colours would be perfect, even if you use as much white as possible. But what happens if you need pure red 75%,0%,0% ? You need to compromise the picture quality in some way. You can either reduce the colour purity or dim the pixel below the desired brightness. That would be either 15%W,60%R,0%,0% or 0%W,60%R,0%,0%.

From what I've read, LG WOLED TVs have significant image processing behind the scenes. There is a very aggressive automatic brightness limiter because of a strict power budget for the whole panel. This means that a full screen of pure white is very dim compared to pure white box in the middle of normal image.
 
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Offline tooki

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #126 on: February 08, 2022, 07:37:41 am »
I'm still watching an old Pioneer Kuro plasma that I purchased new in 2009. These were the last of their kind and the image quality can be really good with plasma. It also has its limitations so I've always yearned for something better when it finally dies.

I expect I'll buy a decent OLED model to replace it and this will probably cost more than I paid for the Pioneer plasma in 2009. I'd happily pay double if I get a significant improvement compared to the (flawed but still impressive) plasma image quality.
FYI, when Pioneer discontinued plasma production, they sold the Kuro technology to Panasonic, so at minimum the late higher-end Panasonic plasmas in essence are Kuro panels.

My Panasonic  is a 2008 model (I got it in 2009, when I was able to buy the top-of-the-line 2008 model for the same price as the entry-level 2009 model.), so it can’t be a Kuro in disguise, and it’s still a great TV. The black levels aren’t as black as modern LCDs (never mind OLED), but the color quality and viewing angle are superb.
 

Offline tooki

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #127 on: February 08, 2022, 07:40:56 am »
It’s not a boost, dude.  :palm: It’s replacing the white component of the RGB channels. That’a a dynamic subtractive process.

And you do realize that computation can be analog? (Just like the YUV->RGB transform done in analog color TVs.) I never said it had to be digital.

If R+G+B = W, and the colour balance of the white pixel is set such that the output of the white pixel equals the sum of three equivalent RGB pixels at similar luminosity, I can't see why it would change anything about the colour balance.  All of this colour mixing nonsense just sounds like "videophoolery".  Our eyes have three cones, and the red and green cones sense very similar wavelengths.  What we see is going to be limited to that - so why would using a colour model that is different create such a vastly different experience?
Exactly. It sounds to me like he thinks they’re just adding white to all the colors indiscriminately, washing it out, or that it’ll somehow reduce the available color space?
 

Offline magic

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #128 on: February 08, 2022, 08:59:18 am »
It sounds to me like he thinks they’re just adding white to all the colors indiscriminately, washing it out, or that it’ll somehow reduce the available color space?
He says that this is what they do to exceed the brightness available from RGB pixels alone when such brightness is called for.

Which doesn't sound completely implausible. Consumer technology is crappy like that and it doesn't get more consumer than TV :P
 

Offline NiHaoMike

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #129 on: February 08, 2022, 12:49:19 pm »
Our eyes have three cones, and the red and green cones sense very similar wavelengths.  What we see is going to be limited to that - so why would using a colour model that is different create such a vastly different experience?
Except for the few who have 4 kinds of cone cells.
https://en.wikipedia.org/wiki/Tetrachromacy#Humans
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Offline BrianHG

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #130 on: February 08, 2022, 01:04:29 pm »
If the big fat white pixels were the true solution, then the first QD-OLED panels would have had them too.

As for the negative color offset mentioned earlier with the image processing, yes when having the 'yellow' sections on the color wheel of the DLP projectors, you do need the 9 channel color space converter instead of the normal 3 channel one to try to attempt further correction which would not be required on a CRT with a strict WRGB 4 channel phosphor.  Just the offset recognition of the white additive boost which can be done within the analog multiplier circuitry of the YUV to RGB converter in most TVs.

The best solution is to get the standard gan blue LED layer to be printed/deposited in a compatible chemistry to a silicon active-matrix layer which will not age as quickly as the organic elements currently in use.  I'm sure a clever means will come up which will give us a huge power budget boost per panel with pixels which will last much longer.
« Last Edit: February 08, 2022, 01:06:44 pm by BrianHG »
 

Offline Zero999

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #131 on: February 08, 2022, 01:52:47 pm »
I don't see how adding an extra colour such as yellow, or white, especially the latter, can be a good thing for colour definition. It will increase intensity, but at the loss of colour definition, at higher intensities.

Colour definition can be improved by using red, green and blue emitters with narrow peaks. Using far red, >700nm, rather than bright red, helps a lot, because it will not stimulate the green cones so much, but is much less efficient.

« Last Edit: February 08, 2022, 05:54:54 pm by Zero999 »
 

Offline PlainName

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #132 on: February 08, 2022, 02:03:28 pm »
If you're looking at a bright light, don't surrounding colours get washed out? A bright red in front of a brighter white is a dull red, isn't it?
 

Online coppice

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #133 on: February 08, 2022, 02:49:15 pm »
I don't see how adding an extra colour such as yellow, or white, especially the latter, can be a good thing for colour definition. It will increase intensity, but at the loss of colour definition, at higher intensities.
It depends what the panel is for:
  • For a TV (or anything else displaying natural images, rather than tightly constrained graphics) it works extremely well. Our eyes don't normally see rich colour in fine image detail. That's why analogue TV could get away with a far lower definition for colour than for luminance. Most "pictures" aren't tightly aligned with the pixels, so we are rarely looking at distinct individual pixels displaying distinct saturated colours. Digital cameras don't equally prioritise R, G and B, so the source for material displayed on TVs is not like a clean R + G + B image, anyway. The vast majority of what you see on a TV has been further compressed between the camera and the display in ways which reduce the colour definition quite markedly.
  • For a computer monitor (or other graphics display panel) it works really badly. Computers display highly unnatural images, which only look right when tightly aligned with the pixels. We view these panels from a short range, where we are highly aware of the individual pixels, rather than seeing them blending into a picture. Here even an RGB panel, which must have a spatial separation between the R, G and B pixels, has issues. We sit close to the display, and can often clearly see that a single line of pixels of a non-primary colour is actually adjacent lines of the primary colours.
 

Online coppice

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #134 on: February 08, 2022, 02:51:09 pm »
If you're looking at a bright light, don't surrounding colours get washed out? A bright red in front of a brighter white is a dull red, isn't it?
Any sufficiently bright light basically looks white(ish).
 

Offline tooki

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #135 on: February 08, 2022, 04:52:39 pm »
It sounds to me like he thinks they’re just adding white to all the colors indiscriminately, washing it out, or that it’ll somehow reduce the available color space?
He says that this is what they do to exceed the brightness available from RGB pixels alone when such brightness is called for.

Which doesn't sound completely implausible. Consumer technology is crappy like that and it doesn't get more consumer than TV :P
But that’s not what the white is for per se. It’s to offload the white component of the RGB value to a white subpixel to reduce wear on the blue subpixel. It’s not that the RGB subpixels can’t achieve the desired brightness, it’s that doing so wears out the blue subpixel faster.
 

Offline tooki

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #136 on: February 08, 2022, 04:58:37 pm »
I don't see how adding an extra colour such as yellow, or white, especially the latter, can be a good thing for colour definition. It will increase intensity, but at the loss of colour definition, at higher intensities.
It’s the exact opposite: while human vision peaks at certain wavelengths, our color receptors actually have very shallow curves, meaning we are still quite sensitive to other wavelengths besides the peaks. This, together with the reflectivity characteristics of objects, is why so many physical objects look awful under RGB “white”. And while we can simulate many colors on displays with well-chosen RGB wavelengths, it’s not 100%, and yellow is one area where we are really sensitive to it being “off” because skin tones are yellows to reds. Hence Sharp’s attempt to improve color rendition with a yellow subpixel. It certainly wasn’t for brightness, since if anything, the added pixel structure reduces overall brightness.
 

Online coppice

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #137 on: February 08, 2022, 05:05:16 pm »
while human vision peaks at certain wavelengths, our color receptors actually have very shallow curves,
Well, of course they do., If they only responded to 3 narrow spectral bands we'd have some really funky gaps in our vision.
 

Offline TimFox

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #138 on: February 08, 2022, 05:21:33 pm »
Exactly.  A wavelength between two broad peaks in the human eye's sensitivity spectrum excites more than one receptor.
Note that although "wavelengths" (e.g., narrow laser spectra) have "color", a "color" or "hue" typically has a broad spectrum of "wavelengths".
What is the wavelength of "brown"?
 

Offline magic

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #139 on: February 08, 2022, 05:27:55 pm »
But that’s not what the white is for per se. It’s to offload the white component of the RGB value to a white subpixel to reduce wear on the blue subpixel. It’s not that the RGB subpixels can’t achieve the desired brightness, it’s that doing so wears out the blue subpixel faster.
It makes other pixels smaller so saturated colors can't reach the same level of brightness anymore, or the pixels are driven harder than before under such conditions (and may wear out faster still).

And there is obvious marketing benefit in cranking up contrast by cheating with those white pixels.

For anyone interested, the controversy should be easy enough to settle by observing Windows BSOD under a loupe :horse:
« Last Edit: February 08, 2022, 05:33:44 pm by magic »
 

Offline Zero999

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #140 on: February 08, 2022, 06:31:33 pm »
I don't see how adding an extra colour such as yellow, or white, especially the latter, can be a good thing for colour definition. It will increase intensity, but at the loss of colour definition, at higher intensities.
It’s the exact opposite: while human vision peaks at certain wavelengths, our color receptors actually have very shallow curves, meaning we are still quite sensitive to other wavelengths besides the peaks. This, together with the reflectivity characteristics of objects, is why so many physical objects look awful under RGB “white”. And while we can simulate many colors on displays with well-chosen RGB wavelengths, it’s not 100%, and yellow is one area where we are really sensitive to it being “off” because skin tones are yellows to reds. Hence Sharp’s attempt to improve color rendition with a yellow subpixel. It certainly wasn’t for brightness, since if anything, the added pixel structure reduces overall brightness.
The light from the TV is not used to illuminate objects. The aim is to reproduce as larger range of colours as possible, so it's more desirable to have sharp peaks from the red, green and blue emitters, to ensure they only excite the intended cones.The eye can't distinguish between spectral yellow and a mixture of red and green light, so there is no point in having a yellow emitters on the screen.
 

Offline bw2341

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #141 on: February 08, 2022, 06:35:50 pm »
It sounds to me like he thinks they’re just adding white to all the colors indiscriminately, washing it out, or that it’ll somehow reduce the available color space?
He says that this is what they do to exceed the brightness available from RGB pixels alone when such brightness is called for.

Which doesn't sound completely implausible. Consumer technology is crappy like that and it doesn't get more consumer than TV :P
But that’s not what the white is for per se. It’s to offload the white component of the RGB value to a white subpixel to reduce wear on the blue subpixel. It’s not that the RGB subpixels can’t achieve the desired brightness, it’s that doing so wears out the blue subpixel faster.

LG's white OLED TV displays are effectively a uniform array of white OLED subpixels. A blue emissive layer is combined with an orange emissive layer to make white. Red, green and blue filter stripes are use to make the RGB subpixels, just like in an LCD TV. For the white stripes, the subpixels are simply left unfiltered.

So in an overly simplistic analysis, the white subpixels are three times brighter than the red, green and blue subpixels at the same power level.

My criticism of LG's design shouldn't be considered an attack. The competition between LG's OLEDs and Samsung's LCDs is excellent for consumers as they've raised picture quality and lowered prices at the same time. Still, we have to acknowledge both the advantages and disadvantages of any new technology.
 
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Online tom66

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #142 on: February 08, 2022, 06:45:44 pm »
From what I've read, LG WOLED TVs have significant image processing behind the scenes. There is a very aggressive automatic brightness limiter because of a strict power budget for the whole panel. This means that a full screen of pure white is very dim compared to pure white box in the middle of normal image.

This is pretty common on emissive displays.  Most plasma display panels exhibited the same effect where the maximum number of sustain fields was limited by the number of set pixels.

For the Pioneer Kuro, for instance, the typical ABL was about 60%, so once more than 60% of the panel was full white (or some greater proportion was grey) the panel would dim.  The dimming is progressive to keep the overall power limit at a peak.

You could override this in the service menu, turning the ABL threshold up to about 80%, which increased the brightness.  The consequence was the set would pull about 800W on full white, and the PFC section on the PSU would occasionally chirp (possibly going into current-limit hiccup) - though with no noticeable effect on the picture as there was enough bus capacitance to hold the whole set up for way too long. 

I didn't run my panel long in this configuration, I was sure something would break!  But, it was damn bright on full white.

I'm not sure what the ABL is on a WOLED, but the effect on a plasma display was only really visible under certain situations; the film THX1138 comes to mind.  And, your eyes tended to adjust reasonably quickly, so it never bothered me.
« Last Edit: February 08, 2022, 06:49:13 pm by tom66 »
 
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Offline tooki

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #143 on: February 08, 2022, 06:51:10 pm »
I don't see how adding an extra colour such as yellow, or white, especially the latter, can be a good thing for colour definition. It will increase intensity, but at the loss of colour definition, at higher intensities.
It’s the exact opposite: while human vision peaks at certain wavelengths, our color receptors actually have very shallow curves, meaning we are still quite sensitive to other wavelengths besides the peaks. This, together with the reflectivity characteristics of objects, is why so many physical objects look awful under RGB “white”. And while we can simulate many colors on displays with well-chosen RGB wavelengths, it’s not 100%, and yellow is one area where we are really sensitive to it being “off” because skin tones are yellows to reds. Hence Sharp’s attempt to improve color rendition with a yellow subpixel. It certainly wasn’t for brightness, since if anything, the added pixel structure reduces overall brightness.
The light from the TV is not used to illuminate objects. The aim is to reproduce as larger range of colours as possible, so it's more desirable to have sharp peaks from the red, green and blue emitters, to ensure they only excite the intended cones.The eye can't distinguish between spectral yellow and a mixture of red and green light, so there is no point in having a yellow emitters on the screen.
I didn’t say TVs are used to illuminate objects.
If we had absolutely perfect RGB emitters, the above theory would hold. But a) we don’t (the peaks may not be where they need to be, and in filtered subpixels, they are often impure and allow some white to “leak”), and b) yellow subpixels allowed some of the spectral yellow light from the white light sources used to be utilized to improve color rendition.

I’d be curious to know why RGB LED backlighting hasn’t become widespread in LCDs, instead we create broad-spectrum white light and filter it. Sony does it in some models (“Triluminos”), but I’m not aware of others.
 

Offline bw2341

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #144 on: February 08, 2022, 06:57:43 pm »
I’d be curious to know why RGB LED backlighting hasn’t become widespread in LCDs, instead we create broad-spectrum white light and filter it. Sony does it in some models (“Triluminos”), but I’m not aware of others.

It is very common, but not with RGB LEDs. Quantum dot enhancement film is used in front of a pure blue LED backlight. The film has a mix of red and green quantum dots that efficiently convert the blue light to narrowband red and green light.
 

Offline tooki

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #145 on: February 08, 2022, 06:59:27 pm »
I’m aware of that approach too, but does anyone beside Samsung make panels like that?
 

Offline bw2341

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #146 on: February 08, 2022, 07:02:01 pm »
Everyone?

It seems like every brand, including the discount ones offer quantum dot products at the top of their lineup.
« Last Edit: February 08, 2022, 07:03:44 pm by bw2341 »
 
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Offline tooki

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #147 on: February 08, 2022, 07:08:03 pm »
Huh, it looks like Sony reused the Triluminos name to mean quantum dots long ago. I hadn’t realized they’d abandoned the RGB LED Triluminos.
 

Offline Jester

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #148 on: February 08, 2022, 08:18:19 pm »

in·vest·ment
/inˈves(t)mənt/

the action or process of investing money for profit or material result.

I have never viewed a TV as an investment.

We don't watch a lot of TV so when the old one dies, we do a quick review search to find out what's good and what's bad mostly from a reliability perspective and then go purchase what is on sale that day that matches the list we just spent 10 minutes researching. There is usually some enthusiastic shopper while we go that is into the latest and greatest and will probably pay  5 or 10 x what we will pay to get the latest feature.

Years ago when big screens were all the rage our neighbors the "Joneses" just could not help themselves and purchased this massive monstrosity. They put the cardboard box on the front lawn for like two weeks supposedly so there son could play in it. There son was about 13 YO at the time. I felt sorry for them, but we did have a few good chuckles.
« Last Edit: February 13, 2022, 04:42:59 pm by Jester »
 

Online tom66

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Re: An expensive TV is a poor investment, and people spend FAR too much on them
« Reply #149 on: February 08, 2022, 08:49:58 pm »
I’d be curious to know why RGB LED backlighting hasn’t become widespread in LCDs, instead we create broad-spectrum white light and filter it. Sony does it in some models (“Triluminos”), but I’m not aware of others.

A few years ago there was hype over blue-phase displays that would work kind of similar to this display Mike tore apart:


... but for full-colour active matrix.  The advantage is obvious: you eliminate the three subpixels, so you can simplify the manufacturing of the panel and drive electronics.  The RGB transition rate however would need to be quite fast to get over the rainbow effect, probably above 100Hz (I'm not sure how fast DLP colour wheels go in the real world) which would put the necessary switching speed around a couple milliseconds.  Allegedly blue-phase could achieve 1ms, but we've still not seen it appear commercially.

Sharp demonstrated a small mobile MEMS display that operated on a similar principle, but instead of an LCD panel, a MEMS array of shutters blocks the backlight.   Another technology I've not heard much from since it debuted - I expect it cost too much.  LCD panels are *really* cheap for what they are, and it's going to take some seriously disruptive technology to shift them.


 
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