Philips makes LCD TVs all CRT-like
By Ryan Block 
posted July 18th 2005 1:50PM
posted July 18th 2005 1:50PM
Even while LCDs are definitely getting better in the smearing/ghosting department (you know, where pixels just aren't refreshing fast enough and blur during quick on-screen motion) Philips announced a novel workaround to the issue. Cycle the LCD TV's backlight completely off while the pixels are in the process of refreshing themselves, and turn it back on when they're in place and ready to be displayed. The backlight has to be three times brighter than usual to compensate for being shut off in cycle (up to 60 times per second, presumably), but mabe this could just be the tipping point for LCDs over plasmas. Expect to see the Buzzing Backlight (that's what we're calling it, anyway) in higher-end Philips devices soon.
Uh, one of the big pluses in my book is that the backlights in LCDs don't flicker. It reduces eye strain over a typical CRT (at least I think so). So not only will they need that, but I'm guessing these bulbs will cost more, not last as long (from being turned on and off all the time), and probably consume more electricity (as I would think rapid switching takes more power than a constant on).
Sounds about as useful as their Ambilight technology. I guess we'll see though.
Uh, one of the big pluses in my book is that the backlights in LCDs don't flicker. It reduces eye strain over a typical CRT (at least I think so). So not only will they need that, but I'm guessing these bulbs will cost more, not last as long (from being turned on and off all the time), and probably consume more electricity (as I would think rapid switching takes more power than a constant on).
Sounds about as useful as their Ambilight technology. I guess we'll see though.
It sounds seizure-iffic!
Sounds like something that would increase power consumption dramatically.
Yeah, switching like that takes up a lot more power than a constant on. Plus the transistors have a certain turn-on time so there'll be a few microseconds of delay as well (however unnoticeable in a tv).
No, it'll decrease power consumption, because the light will be on less.
Yeah, I'm concerned about CRT flicker. One of the primary reasons I use LCD monitors for my computers.
I'm gonna have to agree with the first poster here; Personally, I don't even see why the ghosting is such a big deal to begin with (maybe just because my LCD doesn't do it much) but even so, I'd MUCH rather have a ghosting problem than flicker.
No thanks, Philips.
Nobuyuki: It probably will increase power consumption because the act of turning on your backlight over 1 millisecond uses more power than just leaving it on for one millisecond. That's why lights usually burn out when you turn them on. More power is required to start it up.
Depends on what the source of backlight is. If it's LED (which is the only logical choice, for a couple of reasons), it'll require less power.
Most LCD panels are lit by CCFL. This means that staring at your LCD panel is somewhat like staring at a flourescent lamp. There is flicker. It's not as bad as CRT tubes as each pixel needs to be refreshed, but don't be fooled by the "There's no flickering" crap. :-)
Does it fix the problem of poor blacks with LCDs? Because that's one of my peeves. Plus color range on most LCD TVs sucks compared to plasmas IMHO.
Nobuyuki Idei : "Depends on what the source of backlight is. If it's LED (which is the only logical choice, for a couple of reasons), it'll require less power."
Assuming LEDs wouldn't require more power to switch on and off continuously, then there's still "The backlight has to be three times brighter than usual to compensate for being shut off in cycle (up to 60 times per second, presumably)".
If the backlight on/backlight off ratio in one cycle exceeds 1/2 (or backlight on represents more than 1/3rd of a cycle), then it should consume more power than usual i guess.
It would all depends on how long a complete screen refresh lasts in a cycle.
Ghosting is not the biggest issue with LCD's anyway (though it's one) - black level is. And this won't do anything about that.
Philips is really going in some weird directions with their TV's lately. I saw that Ambilight thing in a store this weekend and I just can't even imagine living with that; it's not even a gimmick that looks good in a store, which doesn't bode well for how it would do in a home. This flickering LCD light seems like a real step backwards - "hey, let's give our high-end LCD's all the problems inherent with LCD technology, *and* the worst of CRT technology too - flicker!"
I mean, CRT's do still have a nice picture, but they've got issues too. I don't much see the point in incorporating CRT's *problems* into new technologies just to make them more "CRT-like". Next thing you know Philips will be purposely screwing up the geometry and simulating misaligned convergence on their LCD's just to further this goal. "No more will you have to deal with perfectly straight lines and distractingly high sharpness and resolution!"
LEDs don't take any extra power to switch on and off, this is why LED torches that have lower power dim modes do so by just cycling on and off at a fast rate.
I really doubt they could pull it off using CCFLs, as they do take significant amounts of power to turn on, and usually have some startup delay (initial surge is required to start the gas glowing.)
If they managed to get the timing down absolutely perfect, you shouldn't notice the flicker as it would be blocked by the pixels during change, but I seriously doubt it will be an easy thing to sync lights with LCD pixels at 60hz+.
Jeff: "Ghosting is not the biggest issue with LCD's anyway (though it's one) - black level is. And this won't do anything about that."
Well, assuming that the backlight in the new Philips LCDs is LED (versus CCFL), a related techique may help with black level. I've already seen reports of upcoming LCD displays where the backlight brightness is modulated based on (average?) scene brightness. This has the effect of dramatically increasing subjective contrast range, though with deleterious effect on gray scale.
Sony's VPL-HS51 3 panel LCD front projector has employed the technique to great success, albeit with an iris rather than direct modulation of the light source.
I think the proof will be in seeing it, but as someone else pointed out, it's not pixel smear during fast motion that seems to be the biggest problem with LCD's it's the lack of 'black' caused by light bleeding through pixels that are supposedly completely off. This reduces the contrast ratio noticeably and also interferes with low level light perception. Very dark images are much harder to make out on an LCD than on a crt because of that.
I'm not even gonna comment on what technology they are going to use for the light but I do have this to say : if it's LED I expect that the 'white' won't be a very good white.
I don't like the 'white' that current 'white' LEDS make. It seems very cold and lacking in warmth to me. Maybe they should try tacking TWO lcd's in front of each other to increase the black level instead.