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Philips Working on LCD TV Ghosting
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."
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.
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.).
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.
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.
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 Boy will I be glad when CRT technology becomes cheap enough to replace those dinky, thin, horridly outdated panel displays.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!
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).
retrorocket.o not found, launch anyway?
"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!"
"Who says nothing is impossible? Some people do it every day!" - Alfred E. Neuman
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.
A witty
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.
I'd say more, but my guild is raiding.