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Television Media

Philips Working on LCD TV Ghosting 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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Philips Working on LCD TV Ghosting

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  • Great. (Score:4, Insightful)

    by Anonymous Coward on Wednesday July 27, 2005 @09:11PM (#13181993)
    Remove one of the advantages of LCD screens, why don't you?
  • by Osty ( 16825 ) on Wednesday July 27, 2005 @09:13PM (#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.

  • Great (Score:1, Insightful)

    by Anonymous Coward on Wednesday July 27, 2005 @09:20PM (#13182050)
    So now I need to worry about my LCD's refresh rate in addition to its response time. That's fantastic!
  • Three times worse? (Score:3, Insightful)

    by dereference ( 875531 ) on Wednesday July 27, 2005 @09:34PM (#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.

  • by ivan256 ( 17499 ) * on Wednesday July 27, 2005 @10:58PM (#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'.
  • Good point, BUT (Score:5, Insightful)

    by Andy Dodd ( 701 ) <atd7@cornell . e du> on Wednesday July 27, 2005 @11:11PM (#13182625) Homepage
    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.
  • by ergo98 ( 9391 ) on Wednesday July 27, 2005 @11:51PM (#13182828) Homepage Journal
    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.
  • by dn15 ( 735502 ) on Thursday July 28, 2005 @02:14AM (#13183415)
    You make a good point -- some people are comparing apples to oranges when looking at an LCD TV vs. an LCD monitor. Personally, between my home and work computers, I am using four LCDs and no CRTs. Whee! It makes a huge difference in the way I feel at the end of the day. No headaches (unless it's simply from lack of sleep! :))

    But the TV is a whole different story. I spend far less time in front of it, and in a proximity nowhere near how close I sit to my computer(s). CRT TVs are not hard on the eyes while CRT monitors are, and it's because they are used in very different ways.
  • Re:CCFL tube (Score:3, Insightful)

    by lxs ( 131946 ) on Thursday July 28, 2005 @03:23AM (#13183614)
    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.

    Our definitions of 'not long' seem to differ slightly. 50k-100k hours is about six to twelve years running contiuously, or about 15-30 years if you get off the couch once in a while and have your TV on for ten hours a day. I can't remember a CRT that was still crisp and bright after 20 years in service.
  • by evilviper ( 135110 ) on Thursday July 28, 2005 @05:31AM (#13183842) Journal
    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.

    It's not easily noticable with normal action. It just looks slightly blury around motion, which can match with the colors well-enough.

    Where it looks REALLY bad is in animation, since you have the sharp contrasts between neighboring pixels. And also, if you watch most news programs, they like to have sharp transitions, like a picture sliding-in from the side of the screen. These quick transitions look very blurry.

    That said, this all goes back to the first rule of video. If you can't see it, DON'T LOOK FOR IT. Once you concentrate enough to see some artifact, you'll find it very, very difficult to ignore in the future. Your eyes will be drawn to it from then on. Some people go as far as getting rid of their TVs shortly after they first spot some defect that was pointed out to them.

    In this case, ignorance is bliss.
  • by Moraelin ( 679338 ) on Thursday July 28, 2005 @06:56AM (#13184101) Journal
    "If the pixels can respond to any signal within 5 ms"

    I took the liberty of adding the emphasis to the keyword there, because that's the whole problem with the current generation of LCDs.

    Yes, the day a TFT can completely switch between any two colours in 5ms or less, will be the day we'll stop complaining about ghosting anyway. Heck, even 12ms will do just nicely, _if_ it can actually switch between any two colours in that time.

    But the problem with current monitors is that the numbers claimed by the manufacturer are bullshit. They're the best case scenario, not the worst case scenario. The worst case scenario for a "5ms" monitor can be almost 30ms for a single transition. (See some of the measurements on Tom's Hardware, and boggle.) Or you have "16ms" monitors which actually switch slower than "20ms" ones. (Not a joke: again, see any review on Tom's or Anandtech, and boggle at how the 20ms panel is actually the faster one.) Or "25ms" panels showing 140ms worth of actual latency.

    The industry has been pretty much left to define for itself wth it wants to measure and how, and what ideal scenario numbers it wants to publish. And unsurprisingly, it did pick the ones that the marketroids liked, not the ones who bear any relevance for the consumer. So you get stuff like numbers measured in perfect darkness, and only until it gets within (an ever increasing) x% of the desired colour, etc.

    Most of the improvement between the 140ms displays of the late 90's and the "6ms" displays of today isn't the actual panel, it's in creative measuring and advertising. The real latency did go down, yes, but the claimed latency went down exponentially faster. Every time the actual latency halved, someone invented an even more creative way to claim half of that again in marketting materials.

    And then you have outright bullshitters. E.g., manufacturers who shamelessly advertise lower response times than even the panel manufacturer claims. (Sony was for years such a case: they quoted either the time to rise or the time to fall, long after everyone else had been dragged kicking and screaming into quoting the sum. So your uber-expensive new "25ms" Sony would in fact have more latency than a "40ms" from Iiyama.)

    _That's_ the problem with those latency numbers: so far they're bogus, and they're likely to stay bogus. When that 5ms monitor hits the shelves, it may be (and probably _will_ be) actually nowhere _near_ being able to display a clean 200 fps. You're lucky if you can get a clean 30fps worth of latency on the worst case scenarios, and for more "normal" 12-16ms monitors you might get 10-20 fps class ghosting.

The faster I go, the behinder I get. -- Lewis Carroll

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