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Philips Working on LCD TV Ghosting

Hemos posted about 9 years ago | from the ghost-in-the-machine dept.

Television 211

agentfive writes "Philips is working on a new lamp technology to eliminate ghosting. Ghosting is a problem in LCD TVs when tiny pixels creating the image take time to switch on and off and can't do it fast enough. The problem, widely recognized as the main drawback of LCD TVs, is apparent in fast moving objects such as tennis balls, but even slower moving images get fuzzy. Philips will do something similiar to a Cathode Ray Tube (CRT) by switching the fluorescent backlight on and off at a rapid pace."

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So... I guess you could say (4, Funny)

Anonymous Coward | about 9 years ago | (#13181990)

They're ghostbusting.

Re:So... I guess you could say (1)

JoshRosenbaum (841551) | about 9 years ago | (#13182130)

Let's just hope they don't cross the streams or we're all doomed!

Re:So... I guess you could say (5, Funny)

datafr0g (831498) | about 9 years ago | (#13182133)

"There's something I forgot to tell you guys, don't cross the beams"

"Why?"

"It would be bad"

"Bad?"

"Imagine every pixel on the screen exploding at the speed of light"

"Ok, good safety tip there guys!"

Re:So... I guess you could say (0, Offtopic)

Entropy_ah (19070) | about 9 years ago | (#13182171)

da na na na na na na... da na na na na na!

Who you gona call? /I have no idea why I just did that

Great. (4, Insightful)

Anonymous Coward | about 9 years ago | (#13181993)

Remove one of the advantages of LCD screens, why don't you?

Re:Great. (5, Informative)

Andy Dodd (701) | about 9 years ago | (#13182105)

I was just about to say the same thing.

I'd rather have slight ghosting (which on any modern LCD is not noticeable, at least for me) rather than 60-75 Hz flicker.

And unlike one of my best friends, I'm not photosensitive (i.e. gets sick in the presence of flickering lights such as fluorescents and low refresh rate CRTs). I have a friend that is photosensitive and does video editing work, and basically HAS to have one of the following:

Extremely high refresh rate (100 Hz+) CRT
or LCD

Even the extremely high refresh rate CRTs bother him a lot. I've had to reassure him when he goes monitor shopping that the fluorescents used in LCDs (almost always CCFLs) switch at rates a few magnitudes of order higher than normal fluorescent lights. (50-150 kHz instead of 60 Hz).

Re:Great. (0, Redundant)

fingerfucker (740769) | about 9 years ago | (#13182349)

I'm not photosensitive (i.e. gets sick in the presence of flickering lights such as fluorescents and low refresh rate CRTs).

Photosensitive? So you have a reaction in response to light. Any light.

Or did you really mean that you have a type of epilepsy called Lafora's disease...?

Sheesh, one would hope that people can be competent at least when describing their own problems that they have to deal with every day...

Re:Great. (1)

bcattwoo (737354) | about 9 years ago | (#13182568)

Sheesh, one would hope that people can be competent at least when describing their own problems that they have to deal with every day...

Or one could hope that people can use reading comprehension (see that word "not"?) to realize that he does not have a problem, but rather his friend is the one that is "photosensitive".

You can simulate LCD "ghosting" with a CRT (0)

Latent Heat (558884) | about 9 years ago | (#13182397)

In some regards, geeks are at the forefront of appreciating the fine points of technology. In other regards, geeks are too ready to engage in the "suspension of disbelief" required to accept a technology on its own terms and don't see things as the rest of the world does.

I believe it was in "Accidental Empires" where the author is amused by some geek trying to tell him how great a LaTeX manuscript looked. To the author, the Computer Modern font rendered on a 300 DPI laser printer looked like a blurred mess, especially compared to a book done on a photo typesetter, but to the geek, the LaTeX output and the typeset book were indistinguishable.

Look people, there are vision psychology issues with rendering motion on LCD screens, and you all may swear how you like your LCD monitors and even do gaming or view videos and "can't tell any blur compared to a CRT", but there is a big difference, and when there is a big push to make LCDs consumer's primary way of watching TV, there is going to be a problem, and it is encouraging that at least someone at Philips is aware of it and looking into ways of dealing with it.

I came across the motion blur problem because I write software to do digital sound spectrograms or "voice prints." The gold standard for this type of display is the Kay 5500, DSP-based hardware that displays a rock-solid voice print scroll on a VGA monitor -- you may have seen a Kay 5500 on one or other TV crime drama where they "analyse voice prints" to try to pin an answering machine threat on a suspect.

You can do a Kay 5500 type display in software, but it requires synching the scroll to vertical retrace. Once you get such a display, it looks great on a CRT, but it looks like absolute blurry mush on even the fasted-responding LCD.

I tried every which way to scroll an LCD display to get a smooth camera pan effect. Failing that, I tried to rig a CRT to look bad like an LCD. If I set the refresh rate of the CRT to 60 Hz, the scroll looks fine, although the display is quite flickery. At a refresh rate of 120 Hz, the scroll looks great and the flicker is gone. If I run the refresh rate at 120 Hz but repeat the frame for two refreshes, scroll the scene, repeat the next frame for two refreshes, simulating an LCD at 60 Hz, it looks muddy, just like an LCD.

Well, it seems that Philips knows that you have to strobe the image to get a good scroll/pan/motion effect. A movie camera/projector strobes the image; a CRT strobes the image in a kind a progressive-scan sort of way; a CRT holds an unstrobed image, and changes the scene. It is like the difference between an impulse-sampled and a step-sampled D/A.

I wish Philips every success with their strobed LCD. If the Philips technique works, I know I am buying a Philips if I get an LCD HDTV.

Good point, BUT (4, Insightful)

Andy Dodd (701) | about 9 years ago | (#13182625)

That's a case of solving a problem that affects less than 1% of the population (Your specific application where ghosting/motion blur is actually a problem, as opposed to 99% of the population for whom it's been solved adequately on any decent LCD made in the past 5+ years.) in return for bringing back a problem that affects 25-50%+ of the population (flicker-induced eyestrain and headaches are extremely common) and produces SEVERE health risks for a non-insignificant number of people.

Re:Great. (1)

rpd10 (550879) | about 9 years ago | (#13182161)

Introduce the psy effect of strobe to increase the impact of commercials. You'll notice this is being addressed as an issue LCD TV. I've only noticed it on games (also introducing commercials).

motion blur. :D (1)

mr_luc (413048) | about 9 years ago | (#13182304)

Personally, I have never noticed ghosting on ordinary video files -- even action movies, which I've watched on many a dell 19" screen.

The only thing that I have noticed ghosting on is while gaming -- but, since I only use good LCD's (do your homework!) the ghosting is barely noticeable.

What I'm left with, then, is a subtle, clean-looking form of motion blur in my games. Shit, some games steal my megahurts to create that effect! With an LCD, I get it for free!

Trails? Set them to OFF, MOFO! For I -- I have an LCD! /me gets some more coffee.

Re:Great. (1)

Vulcann (752521) | about 9 years ago | (#13182656)

Yoda is that you ?

AYAYYAA (-1, Offtopic)

Anonymous Coward | about 9 years ago | (#13181996)

AYAYAYAYYA GHOSTS

Re:AYAYYAA (0)

Anonymous Coward | about 9 years ago | (#13182162)

Silly moderator. Too bad you wasted a mod point on this retarded post. That really blows.

Good. (0, Troll)

millennial (830897) | about 9 years ago | (#13182003)

This is the primary reason I would never buy an LCD TV. If they can fix the ghosting problem, I'd really appreciate it if they license their solution to other companies, rather than hoard it for themselves and pump up the prices, claiming that it's some sort of "XHDTV" or some such crap.

Re:Good. (1)

akhomerun (893103) | about 9 years ago | (#13182086)

well, this isn't sony we're talking about here, phillips will probably license it.

Re:Good. (4, Informative)

Physician (861339) | about 9 years ago | (#13182134)

RTFA Philips, Europe's biggest consumer electronics maker and among the three biggest TV makers worldwide, will not keep the technology to itself but has instead chosen to sell the new technology to any of its competitors.

Re:Good. (1)

millennial (830897) | about 9 years ago | (#13182494)

Yes, but how much of a price hike will this mean? I mean, you'll have Phillips making its TVs that are entirely based on their technology; then you'll have its competitors, that have to add $100 to the cost of an identical TV so they can license Phillips' technology. This is what I'm really worried about.

Re:Good. (1)

ergo98 (9391) | about 9 years ago | (#13182789)

This is the primary reason I would never buy an LCD TV.

Have you actually watched an LCD TV, and compared it against a phosphor television? I'm going to bet that you haven't, and instead you keep hearing about this theoretical ghosting issue of LCDs, and how terrible it is.

The reality is that almost all modern LCDs with 16ms or less response times are very comparable to phosphor sets. Because, as I'm sure you're aware, phosphor sets have plenty of ghosting themselves (seriously - watch when something luminous crosses a darkened screen. It's comparable, in some cases worse, than an LCD screen). Of course they do - the nature of the way that they are lit dictates that they have to use relatively slow fade phosphor or they would look even more terrible than they do.

This solution is just ridiculous, and it's basically some obscure R&D team looking for some sort of edge to make people believe that they need to buy their brand of products. I'll go without the flickering back-light, thanks. When you think about it, the solution doesn't even make any sense except in one particular type of scenario (light to dark).

Replace ghosting for eye strain? No thanks (5, Insightful)

Osty (16825) | about 9 years ago | (#13182005)

In other words, to fix a barely-annoying problem with LCD displays they're willing to get rid of one of the greatest benefits. I'd rather deal with ghosting than have to go back to the days of CRT eyestrain.

Re:Replace ghosting for eye strain? No thanks (1)

Shimdaddy (898354) | about 9 years ago | (#13182070)

I agree, one of the main selling points of LCD's is the lack of eyestrain. This is a dumb move in my opinion.

Three times worse? (3, Insightful)

dereference (875531) | about 9 years ago | (#13182120)

Looks like it's going to be even worse, FTFA:

While the pixels adjust their color, the backlight is off, and it will only switch on when the image is ready -- three times brighter than in a normal LCD TV to compensate for the dark period -- before going dark again.

Won't this make the flicker, oh, I don't know, about three times worse? I realize it's three times an LCD, not CRT, but still that seems like it could cause Pokemon-style seizures or something. Like you said, thanks, but no thanks.

Re:Three times worse? (1)

Fred Ferrigno (122319) | about 9 years ago | (#13182164)

Never had a flicker-related seizure, but I will say that CRTs below 85Hz are very annoying, and CRTs at 60Hz are downright painful.

Unfortunately, every gaddamned monitor seems to default to 60Hz upon first use. As the majority of people can't even tell at 60Hz, I'm frequently "fixing" the refresh rates on friends' computers. They're always really confused and defensive about it too, as if I'm telling them there's something wrong with their monitor. A few people have flat out refused to let me change the refresh rate.

Re:Three times worse? (2, Interesting)

melikamp (631205) | about 9 years ago | (#13182261)

Hey funny you mentioned that. I cannot stand anything less than 75Hz, and strongly prefer 85Hz or higher. I can actually see the difference as I switch from 60 to 75 to 85, 60 being outright painful. And yet when I get to fix or use some friend's computer, I often see that they are running it at 60Hz. After several attempts of trying to explain what is wrong with that picture, I just adapted a rule of surreptitiously changing the refresh rate while the owner is looking away. After all, if they are able to notice it, they can only thank me later.

Re:Three times worse? (0)

Anonymous Coward | about 9 years ago | (#13182767)

I think people become sensitized to CRT flicker over time. Used to be, a long time ago, I had a 60 Hz interlaced computer montitor that didn't bother me. Nowadays I can see flicker at anything below 72 Hz on a progressive scan CRT display. 60 Hz interlaced televisions don't bother me from across the room, however. It's only when I'm up close, like with a computer monitor, that flicker causes me problems.

I recently made a trip to London, and the TV in my hotel room bugged the hell out of me, even from across the room. I think it displayed PAL broadcast stations at 50 Hz progressive scan.

I am not, however, sensitive to the rainbow effect from DLP color wheels.

Re:Three times worse? (1)

name773 (696972) | about 9 years ago | (#13182572)

i never really notice until i have the monitor in the corner of my eye and i focus on something else. then it becomes very apparent. we have this one classroom in school with like 15 computers and all have 15" monitors set at 800x600 and 60hz refresh... they upgraded the computers themselves this year (i was in to get a book), but the monitors carried over. good thing i stop noticing when i focus on the screen itself

Re:Replace ghosting for eye strain? No thanks (0)

zonker (1158) | about 9 years ago | (#13182137)

great... so now that they have the ghosting problem 'fixed' next maybe they can work on contrast ratio and color accuracy, which to me is the bigger problem with both tv, computer monitor and projector lcd's (most decent lcd monitors don't ghost enough to be terribly noticeable).

contrast ratio is pretty craptacular on most lcd monitors, even the best ones. watching movies on an lcd you will notice that the black levels are almost nonexistent. for instance, a dark movie like the lord of the rings: the two towers is very difficult to make out the detail in the dark scenes. on a crt they come out fine, though with arguably lesser clarity (depending on the crt type).

color accuracy is pretty crappy on most lcd's as well (and that is being nice). if you are doing work on a project that needs to have proper coloring, don't use an lcd as your only reference as you will very likely have strange results when compared to a crt or if it is printed to film...

Re:Replace ghosting for eye strain? No thanks (1)

Saeger (456549) | about 9 years ago | (#13182258)

True, most LCD's have crappy contrast ratios, so make sure you get one that doesn't suck.

The LCD I've been lusting after for months -- and that stylish Apple Cinema ripoff victims have been bashing -- is the Dell 24" LCD [barefeats.com] .

Re:Replace ghosting for eye strain? No thanks (1)

Saeger (456549) | about 9 years ago | (#13182282)

Found a great side-by-side image [mac.com] comparison of the Dell 2405 vs Apple Cinema showing nothing but black. Dell wins.

Re:Replace ghosting for eye strain? No thanks (0)

Anonymous Coward | about 9 years ago | (#13182635)

The two monitors share the same Philips LCD panel.

Re:Replace ghosting for eye strain? No thanks (1)

Fred Ferrigno (122319) | about 9 years ago | (#13182654)

It's currently available for $779 [dealnews.com] , the lowest price ever. The 2005FPW, which I bought for ~$500, is also available for an all-time low of $389 [dealnews.com] . Fscking Dell.

The monitor is *awesome*, BTW. Love the rotating base and USB hub. I've made more use of both than I thought I would. Ghosting is no big deal; I watch movies all the time and I've never had a problem.

Re:Replace ghosting for eye strain? No thanks (5, Interesting)

Rothron the Wise (171030) | about 9 years ago | (#13182142)

I'd rather deal with ghosting than have to go back to the days of CRT eyestrain.

There are many reasons why CRTs cause eyestrain, and I'm not convinced flickering is one of them, especially today when most screens can refresh at 85Hz at 1600x1200, and even higher at lower resolutions.

Another problem is the cathode ray tube which by design creates a static electric field on the screen. This field will first attract dust particles in the air, which are then charged with the same polarity as the screen and as a result, they are shot from it, directly at the viewer, something which causes dry eyes. LCDs do not suffer from this problem.

Another problem of the CRT are the analog pixels, which are not perfectly sharp. They are smeared, because the graphics card cannot make abrupt enough changes between colours, and the neighbouring pixels are further smeared as they travel along the VGA cable. (Becomes really noticable at high resolutions and high refresh rates. The signal is pushing the bandwidth limit of the cable). They are also smeared because the electron beam used to paint the pixels is slightly fuzzy. As CRT-screens age, they may increasingly loose focus. Depending on your type of CRT age/price), the image may be blurred further by coatings put on to reduce reflections.

Our vision really dislikes not being able to focus on things perfectly. It puts a strain on the small muscles used to contract the lense inside our eyes.

LCD-pixels are perfect rectangles and does not suffer from these problems as long as a digital interface is used.

Today CRT-screens are superior when it comes to color reproduction, dynamic range. They are also superior when displaying moving images, because of their strobing nature. These new strobing LCDs may change this, something I'm excited about.

Re:Replace ghosting for eye strain? No thanks (1, Interesting)

KillShill (877105) | about 9 years ago | (#13182519)

and they also don't have a "native" resolution crippling every other resolution that requires interpolation to display.

that and ghosting will never go away.

the best lcds have a 25ms response rate (not the bullshit 8, 12, 16 that manufacturers like to lie about) and that's not enough to get rid of ghosting. so they resort to tricks and say that the response rate is now 8ms.

lcds certainly have their place. lower power use, sharper (generally) displays, digital addressing, won't cause hernias for weak nerds/geeks, takes up little desk space.

but for people like me that can lift 22inch monitors and appreciates high end crts for gaming, i cannot make the switch to lcds. not to mention a high end lcd costs over twice as much as a high end crt.

so as the saying goes, the right tool for the job.

i'll continue to use crts for the foreseeable future. maybe OLED or some other technology can finally replace all the features that make crts great and have the benefits of lcds at the same time.

Re:Replace ghosting for eye strain? No thanks (1, Insightful)

ivan256 (17499) | about 9 years ago | (#13182552)

not to mention a high end lcd costs over twice as much as a high end crt.

They did in 2003...

Now you can get a moderately high end (DVI, multi-inputs, 12ms response) 21" LCD for $500 or less while the equivalent 22" CRT costs considerably more. As of early 2005, quality LCDs are cheaper than quality CRTs. Of course this is mostly because there aren't many quality CRTs being made anymore, but that doesn't lessen the point.

I can't measure that my display is really 12ms, but I can tell it ghosts way less than displays I've seen advertised as 25ms. I'd like to know how you prove that it's 'bullshit'.

Re:Replace ghosting for eye strain? No thanks (1)

KillShill (877105) | about 9 years ago | (#13182611)

12ms is some marketing figure mostly.

maybe under ideal conditions and other narrowing restrictions, do you ever see a 12ms response.

if it were a real 12ms lcd, it would uniformly and under all conditions respond at least within that threshold.

they also lie (read deceive) about viewing angles of lcds. this one is much more well known among lcd afficionados. probably a lot of other things, these just are the ones i remember atm.

lcds and crts aren't perfect but they each have their uses. i'm gonna wait another 5-10 years before lcds don't suck as much as now. cause it's already difficult to find good crts now... i can only imagine it getting harder in the years to come.

Re:Replace ghosting for eye strain? No thanks (2, Insightful)

ergo98 (9391) | about 9 years ago | (#13182828)

and they also don't have a "native" resolution crippling every other resolution that requires interpolation to display.

Sure they do - it's just always in some shitty, interpolated mode, so you don't notice. Do you think that the number of physical dots on your screen changes when you change resolutions? It doesn't, it just mishmashes and overlaps them to fit the new resolution. CRTs have a fixed dot pitch, and I highly doubt you're running a 1:1 relationship with them.

so they resort to tricks and say that the response rate is now 8ms.

I'm typing this on a 27" LCD Television (which looks superlative, btw), and have watched a number of action movies, and played games on it, with absolutely zero complaints. The ghosting issue is such a holdover of 1999, and every half-wit, still trying to defend why they can't affort a new LCD display, imagines that they see ghosting all over the place on LCDs, while they carefully block out the same ghosting that occurs on all medium or long persistence phosphor CRTs (which is every high end CRT, humorously enough). Keep on convincing yourself, though.

Re:Replace ghosting for eye strain? No thanks (4, Informative)

Johnno74 (252399) | about 9 years ago | (#13182707)

My friend who is an optometrist has told me the major reason why CRT monitors give you eyestrain and eventually damage your eyes is because of the thickness of the glass.

The image is projected onto the inside of the glass tube, which is nearly 1cm thick.
Your eyes are continually shifting focus between the front of the glass, and the back (where the image is).
Keeping your monitor clean helps a lot, as it stops the eye focusing on the front of the glass so much (less grime to focus on).

LCDs have glass that is very thin, so you don't get eyestrain

Meanwhile... (0, Redundant)

yuri82 (236251) | about 9 years ago | (#13182006)

I'll just stick to my much cheaper and only slightly bigger LDP TVs...

Re:Meanwhile... (0)

Anonymous Coward | about 9 years ago | (#13182041)

Ops, I meant DLP...

Did a little too much LDS? (4, Funny)

XanC (644172) | about 9 years ago | (#13182110)

</oblig ST:4 quote>

Re:Meanwhile... (0)

Anonymous Coward | about 9 years ago | (#13182112)

Laser Disc Player?

I could be wrong...but (4, Interesting)

William Robinson (875390) | about 9 years ago | (#13182009)

Isn't ghosting problem related to the speed at which crystals can reorient?

Re:I could be wrong...but (5, Informative)

Elder Entropist (788485) | about 9 years ago | (#13182028)

Yep. So they're turning off the backlight during the time the crystals are re-orienting. Replacing ghosting with flicker. Might be less noticable because of the limitations of the human eye response.

LCD TVs are fine already (5, Informative)

xythis (882089) | about 9 years ago | (#13182015)

Here's some real number for you. If the pixels can respond to any signal within 5 ms, that means the highest framerate that can be displayed without ghosting is 200 fps (1 / 5ms = 200 Hz). Which is more than you should ever need, and a big improvement on current LCD displays (a good consumer display has a ~20ms response time; 1 / 20ms = 50 Hz, not even 60 fps, but good enough for TV's 30 fps.).

Re:LCD TVs are fine already (1)

kc32 (879357) | about 9 years ago | (#13182084)

Hell, I have an 8ms 17" flatscreen right in front of me.

Re:LCD TVs are fine already (0)

Anonymous Coward | about 9 years ago | (#13182264)

I have a 12ms 45" Sharp LCD 10 feet from me. I have never noticed a problem.

Re:LCD TVs are fine already (1)

DAldredge (2353) | about 9 years ago | (#13182089)

All you 'proof' doesn't change the fact that a large portion of currently sold LCD TV's have issues with ghosting.

Re:LCD TVs are fine already (0)

Anonymous Coward | about 9 years ago | (#13182537)

"All you [sic] 'proof' doesn't change" anything because, as usual, you give no proof.

Re:LCD TVs are fine already (1)

Vegeta99 (219501) | about 9 years ago | (#13182146)

OK, but a CRT's phoshor still loses its glow quicker. Response doesn't mean complete change. Hitting the brakes cuz the light is red doesn't necessarily mean you stop before the intersection.

Re:LCD TVs are fine already (3, Informative)

Trepalium (109107) | about 9 years ago | (#13182247)

Actually, they're not. The response times that are quoted are rise/fall numbers, and those tend to be somewhat faster than grey-to-grey numbers. Try a FPS game on a 16ms display, and you'll see this -- despite the fact the display is limited to 60Hz refresh, and 16ms should be fast enough for 62fps, there's still ghosting in textures. There is an article on this here [pcworld.com] . For example, Viewsonic's VX724 only needs 6ms to transition from white to black to white (two transitions), it takes 4ms to transition from one shade of grey to another (one transition).

Then there's the problem that this technology mentioned in TFA is meant to solve -- the LCDs don't instantaneously switch from one shade to another. They slowly (relative to the response rate) switch from one shade to another. Blur can become visible if the pixel isn't held at a particular shade for enough time before changing again. I suspect this technology is more about getting use out of the slower 20-30ms displays than helping the high speed displays that are more common for computer users. Sadly many LCD TVs on the market today seem to use this slower display panel technology.

There's response times and there's (1)

robbak (775424) | about 9 years ago | (#13182251)

..the time it takes to respond.
Response times are generally the time taken to go from 100% to 0% - and this is generally the best case. Moving from 20% to 80% is a lot slower (source: arstechnica's ~recent lcd rundown)
0-100 rarely, if ever, occours in nature. (unless you're a cheetah!) The tennis ball problem, from green to yellow, is fairly small - 0dff0f to fdff28 was my guesses: big shift in red, green unchanged, slight blue. Even that big redshift would be reduced in real life.
So, yes, it's a problem. Whether giveing us 50/60hz flicker back is a good idea is, of course, another matter entirely.

Re:LCD TVs are fine already (3, Informative)

iamplasma (189832) | about 9 years ago | (#13182277)

Yes, but the problem is that, unfortunately, there aren't any 5ms LCDs yet. In fact, there aren't any 8ms ones, regardless of what the brochures tell you. Those figures are extremely optimistic (ie fake) figures for perfect conditions. In reality even an 8ms (or a new 4ms G-G screen) is often >20ms for many transitions. THG (yeah, yeah, spare me the THG bashing) did a good demonstration of this by showing the actual transition times for the monitors they reviewed. Quite simply, nobody comes close to meeting their claimed specs, so the days of response times low enough to eliminate ghosting totally are still far away, especially for TVs which tend to use higher response time screens.

Re:LCD TVs are fine already (1)

KillShill (877105) | about 9 years ago | (#13182544)

manufacturers who lie? oh my!

Re:LCD TVs are fine already (1)

gfody (514448) | about 9 years ago | (#13182738)

actually the viewsonic vx924 does in fact eliminate ghosting by responding in about 4-5ms. The tom's article pointed out that it still takes an avg of 16ms for the pixel to be within 10% of the requested color.

I have 3 of these things and I can assure you they are nothing short of amazing. Set the refresh rate to 85hz and compare side by side with a CRT and there is absolutely no ghosting what-so-ever.

Even the tom's article gives some credit here [tomshardware.com] IMO they were way to calm about this monitor! people dont RTFA either, just look at the pictures and go "HA more lies!"

they aren't lies. get a vx924, set the refresh to 85hz and try it out.

8ms response time not enough? (5, Interesting)

fake_name (245088) | about 9 years ago | (#13182018)

I recently bought a 17" LCD monitor. It has excellent colour reproduction and I can't notice any ghosting even when playing FPS games. Is there any reason this same technology can't be used on LCD TVs without the need to make everything flicker? I can only guess that the cost is prohibative once you go beyond a certain screen size, but surely the larger pixel size of TV (as opposed to a high resolution monitor) would make fabrication easier.

Re:8ms response time not enough? (1)

bobtodd (189451) | about 9 years ago | (#13182061)

Yep, mine's a 19" (phillips even), 8 ms response, decent colour reproduction, no ghosting that I can see. I know people like their massive Walls O'Entertainment, but I've had TVs smaller than this thing. What's the big difference here?

Maybe it's taking a bit longer for the better tech to 'trickle up' from the PC world? Assuming it is applicable.

Re:8ms response time not enough? (1)

rm999 (775449) | about 9 years ago | (#13182829)

Although they advertise 8 ms, this is only the time for the pixels to change from a certain color to another (i think it's white to black or black to white or something). It is not the worst-case scenario. For example, my 19" Dell LCD advertised 20 ms response, but apparently the worst case was around 50-60 ms. Turns out Dell was optimizing the display for that number. This could possibly be the problem with most LCD's.

8 ms may not be small enough. A CRT monitor usually runs at 60 Hz (17 ms per frame), but the response time of each pixel is much much lower - before the next frame, there is a guarantee that every pixel has been turned off. This completely eliminates ghosting. So if a tennis ball is moving from one side of the screen to the other very quickly, a CRT will draw the ball in discrete steps, whereas a LCD monitor cannot promise this (thus creating ghosting).

Re:8ms response time not enough? (1)

Overzeetop (214511) | about 9 years ago | (#13182316)

Actually, iirc from a previous discusion about LCDs on AVSforum, the larger a crystal, the longer it takes to reorient. The little pixels in a 17" display (or, even better, the 15.4" WUXGA on my laptop) can be switched pretty fast, but you put up a 1024x768 array over 40 or 50 inches and you're talking big pixels.

Re:8ms response time not enough? (0)

Anonymous Coward | about 9 years ago | (#13182558)

How about manufacturers just use a display of 1024x768 "meta-pixels" each made up of four smaller pixels of the size used in 17" displays.

Re:8ms response time not enough? (1)

fingerfucker (740769) | about 9 years ago | (#13182367)

See, the 8 ms response is a response time to fully turn an element on. The response time talks nothing about the time it takes for an element to fully fade out when turning off.

You're right but the measurement isn't *bad* (3, Informative)

cbreaker (561297) | about 9 years ago | (#13182464)

As you know, the response times usually handed out are the time it takes for a pixel to go from black (0) to white (255) or white to black. LCD pixels can do this much faster then they can go from black to grey (128.) Another interesting attribute of LCD pixels is that they can go from white to grey faster then black to grey.

Some new LCD panels take advantage of this knowledge. To turn grey, it will push the pixel to full on, from black (0) to white (255), and then back down to grey (128)- and the whole process takes less time then going from black to grey. Unfortunately, in some circumstances you can see it and it might produce a "sparkle" effect on the video. But it's not distracting.

Anyways, to my original point, manufacturers are recording the response time from black to white, which isn't generally representative of the real performance of the LCD, which may be dismal when going from white/black to grey, or even grey to grey.

However, there's been advances in the manufacturing process and many new LCD screens reduce the ghosting to "can't even notice it" levels even without using tricks.

Friend of mine has a Samsung 19" LCD screen that claims 12ms response. I have a 24" HP 2335 widescreen that claims 12ms. My screen is a gem - it's an underrated screen for the price (You can get them new for $800) and it's in the "can't even notice it" category. Meanwhile, the Samsung is difficult to use for fast paced FPS type games.

I guess my point is that even though the manufacturer might claim 8ms or 10ms or 12 - they might not be bullshitting =) It could be a really awesome screen. But the only way to tell is by actually using the screen, because the current system of measurement doesn't take into account the TTG - time to grey.

Is this really such a problem? (4, Interesting)

aussersterne (212916) | about 9 years ago | (#13182025)

Early LCD displays were bad, sure, but these days I use a CRT at work and a low-end 17" Advueu LCD display at home (on which I watch both TV and DVDs as well, in addition to gaming), and I can honestly say that the LCD's display quality--contrast, brightness, sharpness, lack of distortion--is far better than my Optiquest at work, and I haven't experienced anything even suggestive of a ghosting problem, whether while watching action films or playing FPS games.

i swear this isn't a soviet russia joke (1)

boingyzain (739759) | about 9 years ago | (#13182027)

The question is not "Are LCD displays ready for movies?", it's "Are you ready to for movies on an LCD display?"

Stick a fork in this LCD garbage (5, Funny)

systemic chaos (892935) | about 9 years ago | (#13182029)

FINALLY. Boy will I be glad when CRT technology becomes cheap enough to replace those dinky, thin, horridly outdated panel displays. Then we can fully realize the classic sci-fi television wet dream of dozens of small egg-shaped monitors placed mere fractions of feet apart to simulate a single, moderate-sized screen!

Re:Stick a fork in this LCD garbage (1)

tonywestonuk (261622) | about 9 years ago | (#13182229)

Agreed. Now, one way to make CRT better, might be to replace the single electron gun (or three for color), with an electron source for every pixel......

This is what SED displays are all about. Much better than these shitty LCD's IMO. http://neasia.nikkeibp.com/neasia/001588 [nikkeibp.com]

Re:Stick a fork in this LCD garbage (1)

KillShill (877105) | about 9 years ago | (#13182563)

if only they cost less than 500 and i can pick one up now at my local store. otherwise forget about it.

but it seems it has trouble producing colors as well as crts.

anyway, back to the old drawing board.

motion blur != ghosting (2, Informative)

gangofwolves (875288) | about 9 years ago | (#13182042)


Come on people, get the terminology right. Ghosting and motion blur are not the same thing!

Ghosting is when you get a faint duplicate of the entire on-screen image, slightly offset from what it should be. I don't think this can even occur on LCDs, I think it is a CRT-only problem, but if you use crappy analogue VGA cables, then who knows?

Motion blur is what you thing ghosting is. It is caused by poor refresh times, more specifically it is caused the amount of time it takes for a pixel to become unlit, or "switch off". So LCD screens that have a poor response time often show a trail after a moving object that looks like a ghost of the object.

Understandable that you could get the two confused, but still wrong. /mike

Re:motion blur != ghosting (0)

Anonymous Coward | about 9 years ago | (#13182075)

Alright, show of hands: who here beside mike disagrees with him on ghosting / motion blur?

Re:motion blur != ghosting (1)

boingyzain (739759) | about 9 years ago | (#13182078)

Good points.

I'd like to add that ghosting is usually due to bad or damaged cabling, and that all high-frequency analog signals (including those used by LCD monitors with VGA inputs) are susceptible to it.

It's easy to demonstrate, too: Just take a length of VGA cable, and bend it in half, hard, as if you were a secretary busily rearranging "all those ugly wires". After that, bundle it up with a bread tie, and place the corner of your desk on it.

Or just pretend you're a gamer, strung out from seventeen consecutive hours of cheap beer, bad coffee, and Counterstrike. You're loading the PC into the car, and slam the trunklid on the monitor cable, crimping it something nasty.

Ghosting? You betcha. We expect these cables to run up to about 350MHz. If you thought Ethernet over Cat5 was finicky, you haven't pissed off a VGA cable lately.

[/me patiently awaits the return of monitors with replacable, BNC-equipped cables...]

Re:motion blur != ghosting (3, Informative)

exp(pi*sqrt(163)) (613870) | about 9 years ago | (#13182100)

Ghosting also comes from reflections of incoming radio waves though I'm not sure people watch 'wireless' TV any more.

Re:motion blur != ghosting (2, Interesting)

timmarhy (659436) | about 9 years ago | (#13182262)

actually your totally wrong. motion blur is when an object moves so fast our brains aren't able to disinquish it clearly. ghosting is the effect caused when a pixel changes colour slowly and you see a "ghost" image of whats moving. this effect happens on both crt's and lcd's, however it tends to be more pronounced on lcd's. just move your mouse around the screen quickly on your crt and you will see an example. you look like a right idiot now don't you!

OLED (4, Interesting)

camcorder (759720) | about 9 years ago | (#13182044)

Well but when will wew see TVs using OLED technology. For sure they will be alot better than LCD counterparts.

Great (1, Insightful)

Anonymous Coward | about 9 years ago | (#13182050)

So now I need to worry about my LCD's refresh rate in addition to its response time. That's fantastic!

Read what is written, TV's (0)

Anonymous Coward | about 9 years ago | (#13182068)

People moaning about flicker, etc should realise that TV and monitor use differ alot, especially in viewing distance. So the flicker might be less of a problem, I would not expect them to apply this to computer monitors (although if I get a chance I'll ask some folk at Philips)

Never noticed it with LCDs, but.... (4, Interesting)

Hannah E. Davis (870669) | about 9 years ago | (#13182124)

I must admit that I've never even noticed this problem with LCD screens. Maybe I'm just incredibly unobservant, but you'd think that something that's known as "the main drawback of LCD TVs" would be noticable to even the casual watcher.

When I saw the title of this article, though, the first thing that came to mind was this old TV that belonged to a club at my highschool. It was hooked up to a little camera on a remote-control robotic camera mount that a former club member had created, so the idea was that people sitting in another room could swivel it about with a joystick. Unfortunately, the mount broke, so the camera (which then became known as buttcam, due to its lowered position) ended up stuck looking in the same direction for some long period of time. This background image eventually got burned in somehow, and it got to the point where people could walk in front of the camera and appear transluscent on the TV.... and the end result was something that deserved the name "ghosting" far more than anything an LCD TV can do :)

LCD sucks. (0)

Anonymous Coward | about 9 years ago | (#13182138)


LCOS (Liquid CrystalOn Silicon) rocks. very fast, minimal "screen door" effect. Blows LCD and DLP out of the water.

HUH? (1)

jcr (53032) | about 9 years ago | (#13182176)

So, they're going to re-introduce flicker to deal with ghosting?

Doesn't sound like a win, IMHO.

-jcr

Re:HUH? (0)

Anonymous Coward | about 9 years ago | (#13182196)

They must be using the "I'll give you something to cry about!" approach to technology development.

Re:HUH? (1)

buckhead_buddy (186384) | about 9 years ago | (#13182290)

As a person succeptible to flicker induced seizures, I find this move outright evil.

As you say, they're going to reintroduce a major annoyance for many (and a very real health concern for me), to appear like they've solved the ghosting problem? It doesn't really even sound like they're solving the ghosting issues but just relying on the average person's afterimages to give that perception. I'm sure we'll see a huge return of strange, unquantified headaches that were a common ergonomics complaint back during the late nineties when truly crappy CRT displays were bundled with people's cheap computers (and some crappy speakers too!)

There must be some other advantage to a monitor manufacturer if they see it as a worthwhile risk to RE-INTRODUCE what could be a major health concern. Could they have made LCD monitors too reliable? Perhaps the rapid on and off of the LCD cause more rapid pixel death; and thus promotes a more rapid purchase cycle for new LCD's.

I hope this effort fails miserably.

This is NOT new, nor is it necessarly good (5, Interesting)

feyhunde (700477) | about 9 years ago | (#13182177)

I've some experience in the AMCLD business and gotta say this ideas been around for a while and has several issues. Depending on the display it's more likely to increase aging effects of the back light, making your monitor die that much faster.

Secondly, the image loses color definition due to the backlight's frequency not necessarily producing the same amount of light pure color. Some times red may be better, some times green. If it gets really bad the a color can be completely skiped. Depends on the addressing method of course.

Thirdly if the addressing method prevents the color definition from being an issue as multiple colors are being addressed at once lines may appear over time, or the screen may noticeably flash.

Lastly there is some attempt to increase the power of white while flashing. This can effect the chromaticity of the white (read colors making it up) and make it biased toward yellow (usually). The brightness can also bleed through the black and make the over all contrast ratio suffer.

Now if they got it to work properly, good for them. I'd just rather not get the first model with this tech if I were you.

editors can not read! (1)

phsdv (596873) | about 9 years ago | (#13182202)

"...will do something similiar to a Cathode Ray Tube (CRT) by switching the fluorescent backlight on and off at a rapid pace." Where the heck is this info comming from? CRTs do not have backlights!

In TFA it says:...showed a flat TV that takes the idea of a Cathode Ray Tube (CRT) by switching the fluorescent backlight on and off at a rapid pace. This means that they take the idea of switching from a CRT and implements this into a flat TV, i.e. a LCD. And not the other way around. Can editors not read?

Re:editors can not read! (1)

robbak (775424) | about 9 years ago | (#13182294)

I'd say the editors were a little over brief, not incorrect, or illiterate. Although, I cannot pick the difference between the two statements. CRTs light up a phosphor dots for a very small time (persistance makes this more complex.) That's the idea that the LCD makers are working with.

Offtopic: LCD vs DLP (2, Interesting)

maxrate (886773) | about 9 years ago | (#13182238)

Could we get a poll on slashdot of fav matrix technology?


LCD / DLP / CRT / PLASMA / ??? / ???? / ?????


I prefer LCD over everything else at the moment, including DLP. I don't like the effect of the pixel being switched on/off the produce a shade, where LCD can be varible (control wise) to produce variable shades.


I have owned several projects since 1997. I've never owned a CRT projector, however I like the color on the LCD ones by far. I notice the LCD's don't last as long as DLP. I am using them for entertainment purposes, I'm not doing power point.

Re:Offtopic: LCD vs DLP (1)

SumDog (466607) | about 9 years ago | (#13182259)

My ears are sensetive and I've never been able to get use to the high pitch whine from home theater style DLP projectors (under $1k). I use a Viewsonic LCD now and the quality is much better, not to mention it doesn't hurt my ears

Sumit

Re:Offtopic: LCD vs DLP (2, Informative)

maxrate (886773) | about 9 years ago | (#13182306)

The cheap DLPs have a disc that spins, for a single DLP chip projector the disc has 3 sections, blue/green/red

that is the annoying sound you're hearing.

Unitl you get a 3 chip DLP projector, there are moving parts (fan aside)

I think LCD has better color (personally) but the longevitiy isn't there.

CCFL tube (1)

ValourX (677178) | about 9 years ago | (#13182280)

As it is, the cold cathode fluorescent lamp in LCDs doesn't last all that long. 50k-100k hours before it loses 50% of its brightness. Turning it on and off a lot does not lengthen its life. As with all electronic or electromechanical devices, the most amount of thermal stress you can put on them under standard conditions is to turn them on and off.

So what are we looking at with these new screens? Maybe half the already limited brightness half-life? CCFL tubes are not generally replaceable, even by technicians, and when the CCFL dies, you may as well throw the LCD in the garbage, because you'll never see it again.

Maybe Philips will make a user-replaceable CCFL module that you can just slip in and out?

Re:CCFL tube (0)

Anonymous Coward | about 9 years ago | (#13182751)

As it is, the cold cathode fluorescent lamp in LCDs doesn't last all that long. 50k-100k hours before it loses 50% of its brightness.

Buddy, that would be 20-40 years, think your numbers are wrong there.

tiny pixels creating the image (1)

NitsujTPU (19263) | about 9 years ago | (#13182321)

What about images that are composed of unusually large pixels?

Some information on the nature of the problem (4, Interesting)

Theovon (109752) | about 9 years ago | (#13182342)

The last time I saw this technology was at the 2004 SID (Society for Information Display) show, in Seattle. LG/Phillips had one in their booth. I believe they were using LEDs for the backlights and were cycling rows of them in time with the LCD update. Being 60 Hz, the flickering was noticable, but the ghosting was completely absent.

Here's the problem: With a TV or movie screen, the image is flashed very briefly (on a TV, different parts of the screen are flashed at different times, but that's not important), and your brain stitches the scene together. The hold time on the image is VERY brief, so while it looks like a steady picture, it's really a succession of flashes with relatively long periods of darkness in between then.

With an LCD, on the other hand, you could say that the hold time is as long as the frame period (16 milliseconds or whatever). The LCD has no periods of darkness. With the CRT and movie screen, your brain is what stitches the images together, inferring the motion. With the LCD, you actually see the image change, and your brain perceives that as a smear. IIRC, what's happening is that persistence of vision is working against you and you end up seeing two frames at once.

Besides, raster-scanning the backlight, there are two other things that can reduce the smearing effect. One is to increase the frame rate. The higher the frame rate, the smaller the motion steps. It essentially reduces the hold time on each frame.

At the show, I went to a seminar by a guy named Kompenhouwer. For any device, you can mathematically model how it converts its input to output. This is referred to as a "transfer function". This guy developed transfer functions for the LCD and for a CRT and inserted a filter (It was really precomputed in software, but you could do it in real-time) between the video signal and the LCD that applied the CRT transfer function and inverse LCD transfer function. Those together cancel out the smearing effects of the LCD and make it look more like a CRT. For static images, the filter does nothing, but as I recall, the effect of the filter on motion is to amplify the high-frequency components of the image in the direction of motion. I think that as long as you are tracking the motion of the moving image with your eye, it looks right, but if you don't, it looks weird (but I may be remembering that last bit incorrectly).

been there done that ? (1)

Easy2RememberNick (179395) | about 9 years ago | (#13182344)

switching the fluorescent backlight on and off at a rapid pace.

  I'm no expert but aren't fluorescent lights already off 99% of the time? It's just the way it has to be because of its design and the gas in them.

HELL NO! (1)

Guspaz (556486) | about 9 years ago | (#13182357)

I hope these new displays fail horribly. This is the LAST thing we need...

Modern LCDs have response times so low that the problem is nearly eliminated. Further developments such as overdrive (Increasing response times by going past the desired setting and then back again) have further improved it.

So, WHY are they going to go and introduce flickering LCDs?

This is like hitting someone on the head with a hammer in order to kill a fly. The "solution" is way worse than the problem.

Yay just what ive always wanted! (1)

MrP- (45616) | about 9 years ago | (#13182403)

Finally, an LCD monitor that can give me a headache like my old CRT

I miss my headaches, yay technological advancement!

Re:Yay just what ive always wanted! (1)

KillShill (877105) | about 9 years ago | (#13182580)

perhaps you'd want to use a crt with 100hz or more at the resolution you want to use. hence a high end crt. you were probably using a 99 dollar pos that could only do 75hz.

anything under 100hz flickers for me but i never get headaches.

anyway, try using a high refresh rate next time and see if it goes away.

Fascinating (0)

Anonymous Coward | about 9 years ago | (#13182450)

I never knew that Cathode Ray Tubes used a fluorescent back light!

That's not a fix (1)

infonography (566403) | about 9 years ago | (#13182454)

Adding a flash to the screen will make watching them tiresome. LCD's advantage in readability is the eye does not have to adjust to flickers that TV/Cathode Ray Tube use for persistence of vision. Over time the eye catches the blank spots, the variations in brightness and the pupil contracts and expands to match. LCD has a steady light. I recently started using an LCD screen at work, and I have no intention of going back to a CRT again. My eye strain issues are gone, I walk out of work not feeling tired. I plan to chuck my old model TV soon for an LCD ASAP, and if Phillips is planning to use flicker technology I won't be buying one.

Done! (1)

ZebadiahC (125747) | about 9 years ago | (#13182658)

Its been done already just not with the flourescent backlight but withwhite and RGB color LED backlighting. LED backlit LCD's with no flicker or fuzzy images have already been demo'd

It won't affect all the LCDs (1)

thecoolestcow (890234) | about 9 years ago | (#13182776)

I mean, wouldn't there still be a choice between the type that eliminates ghosting and a regular LCD? I don't see it as a problem, as long as there's still that option. Well but when will wew see TVs using OLED technology. For sure they will be alot better than LCD counterparts. I fully agree; I can't wait either. OLED's are so much thinner, they're flexible, they use much less electricity and they're cheaper to make. It will truly improve all aspects of video and picture technology.
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