Any display benefits to an LED backlight?

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jozu

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So I know LED backlit monitors are thinner and have a lower power consumption, but im curious if they have anything that makes a difference visually. Right now the main monitor I'm considering that has this is the samsung xl2370. What im wondering is:

  1. Because leds can turn off, is contrast better?
  2. Is it better for dark scenes in movies/games?
  3. Are most led backlit monitors edge lit?
  4. Does this effect the potential for backlight bleed? Are these monitors more evenly lit?
  5. Is there any effect on brightness or color?
 
jozu said:
Because leds can turn off, is contrast better?
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Generally, no. Because all current LED-based LCD panels are still edge-lit, there's no appreciable benefit to contrast since the LED can't turn off without rendering non-black areas of the screen black as well.

Is it better for dark scenes in movies/games?
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By virtue of it being LED-based? I wouldn't think so.

Are most led backlit monitors edge lit?
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I believe all current monitors with LED backlights are edge-lit. The era of "fully array" LED backlighting (which will allow for selective dimming and better contrast) has not yet arrived for computer monitors.

Don't know about the latter two questions.
 
Hurin said:
I believe all current monitors with LED backlights are edge-lit. The era of "fully array" LED backlighting (which will allow for selective dimming and better contrast) has not yet arrived for computer monitors.
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The pro. HP DreamColor LP2480zx has tri-colour RGB LEDs (so are high-end Bravia TVs). Not sure... but it may also be edge-lit too..

Is there any effect on brightness or color?
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The white LEDs could be more inferior to wide-gamut CCFL (initially). However, LEDs last longer, would have relatively the same brightness/same wavelength over the course of time. CCFL will dim and loose colour range as it age.

Best would be tri-colour LEDs (RGB), each only generate a specific wave length, the LCD does not have to block all other wavelength in between the 3 colours.

samsung xl2370 is a TN panel, maybe you should get one with PVA or IPS LED back-lit
 
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Sweet, one day we'll see this:

30" LCD
2560x1600 pixels
512x320 LED backlight

Can't wait to see black blacks!!

Not sure how they would smooth out the LED array....some sort of diffuse screen?

Hmm...experimentation required....time to build and array for myself and go at her
 
Askanison2 said:
samsung xl2370 is a TN panel, maybe you should get one with PVA or IPS LED back-lit
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My understanding is that the main benefits of a PVA/IPS panel are color reproduction and viewing angle. In my case I mostly use the monitor to play games or watch movies so accurate color reproduction isn't as important to me as response time. My budget really maxes out at the $300 range so im looking for the best picture I can get for around that price.

That being said, is the visual quality of the xl2370 better than a lower/similarly priced non-led acer or dell unit?
 
The HP DreamColor LP2480zx does not use edge lit LEDs.

Currently no PC monitors utilizes local dimming. Local dimming is the ability to change the brightness of certain sections of the screen in a grid like manner. This can provide true blacks in sections of the screen, however, the downside is the fact that local dimming acts in sections or sectors the covers a large amount of pixels. The result are noticeable "square" white blooms especially against a black background.

My LG 47LH90 uses LED local backlighting and the effect I mentioned above with regards to "white bloom" definitely is noticable specially when the cable box is off and the "No HDMI Signal" message jumps around the screen. This is a great HDTV, but don't expect local dimming on a HDTV or PC monitor to be the "magic bullet" for totally true blacks.
 
LED's have a purer more steady color wavelength so the filters operate better, if they are properly chosen. That makes for better color, IF it's properly done, from white or RGB led backlight units.

LED's backlights have typically a 100k or longer lifespan. While many won't need anywhere near that long a life, that life comes with a plus. The color of CCFL's changes in color temperature over time. White LED's do too, but at a vastly slower rate. RGB LED's hardly shift color at all. What this means is that a properly tuned LED backlit monitor will stay in tune for far longer and thus provide a longer life without color shifts. The reason most folks don't realize that CCFL's change color over time is that our eyes fool us and slow changes in color often elude us. But put a brand new CCFL unit up against the same unit a few years old, and all things being equal, the new one will very noticeable.

So in summary:

Less depth, as backlight takes up less room.
Lower power if the LED unit is done well.
Better color if the LED unit is done well.
Longer color purity over the life of the monitor, as shorter lifespan CCFL's change color temperature over time.
Longer backlight lifespan by around 5x, but few folks burn out a CCFL.
 
How many zones does the LP2480zx possess? I'd imagine a professional monitor has many more zones than a consumer HDTV like the LG LH90.
 
vista_blista said:
How many zones does the LP2480zx possess? I'd imagine a professional monitor has many more zones than a consumer HDTV like the LG LH90.
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No zone. The monitor does not have local dimming capabilities. Local dimming can throw off colors which is not a good thing for professional usage. What's more important is color uniforming and accuracy and of course good black levels.
 
JaguarSKX,
have you connected your LH90 to a PC via HDMI?
How is the PQ and Text?
Is there blooming and Halo?

Since I'm in the market for a 40-42 Lcd as a second display for clients viewing video and graphics, I have narrowed down to mid range Sony V5500 (V5100 in US) and LG LH 90.
The first uses traditional CCFL backlight while the second sports Direct LED w/ Local Dimming and presumable better blacks.
Is Local Dimming Not suitable for PC use?
I'm not keen on its bulky design and the 300 euros more, but if black levels and PQ is way better I'll go for it.
 
I'm thinking CCFLs may still be better. LEDs are point sources while CCFLs are diffuse. Also, CCFLs flicker at a very high rate, 20k-40k times a second.

LEDs however, often use pulse width modulation to dim them. This rate is lower than what the CCFLs use and some people can see it. The way it works is, when they want you to think the display is dimmer, they turn off the power to the LEDs briefly.. the longer the period, the dimmer it seems, but the flashes when it is on, it is on at full brightness. So you're still getting a blast of 500 or more cd/m light if that's what the thing is rated for.

I can see why this may introduce some difficulty in calibrating the display, if the backlight is always at full brightness, just pulsing away based on on fusion thresholds for humans.

LEDs won't be the last technology we ever have for lighting, but I'm thinking for eye comfort what I would want to do is have a LED display that is DIMMER in cd/ms at maximum power. And just never turn it down from there since it won't be using PWM at maximum.

So in my opinion a dimmer darker LED monitor is better than a brighter one that you have to turn down.
 
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