Questions about a purely-LED display

[Green Xenon]

Hi:

 

I’m thinking of a hypothetical monitor for a TV/computer. This display does not use plasma, LCD, or a backlight to any extent. Instead it relies purely on LEDs for emission of light, colors, and images. As with most screens, each pixel contains a red, green, and blue subpixel. However, in this hypothetical monitor, each subpixel consists of a single LED.

 

Each pixel – and its respective subpixels – are as small as physically-possible given the state of today’s technology. The screen contains as many pixels per area physically-possible with today’s technology. These specs ensure that highest possible image resolution.

 

What would be the disadvantages of this purely-LED monitor – besides the cost?

 

Would refresh rate apply to this type of monitor? If so, what would be the maximum refresh-rate possible with this monitor?

 

I think this type of display is the most energy-efficient possible considering today’s technology. Am I right?

 

LED kicks LCD’s butt anyday.

 

These so-called “LED TVs” in the current market as simply LCDs with LED backlights. These evil marketers are so manipulative and the customers who fall for them are so unwise.

 

LCDs reek. When an LCD monitor is turned on, it required more watts to stay dark than to be bright. My hypothetical LED monitor does the exact opposite and is more eco-friendly because it doesn’t waste energy using a backlight.

 

My LED screen totally kills both plasma and LCD technology.

 

Any chance of my theoretical LED display appearing in department stores in the next year?

 

 

Thanks,

 

Green Xenon

[Cap'n Refsmmat]

LCDs reek. When an LCD monitor is turned on, it required more watts to stay dark than to be bright. My hypothetical LED monitor does the exact opposite and is more eco-friendly because it doesn't waste energy using a backlight.

This isn't necessarily true with LED-backlit LCD TVs. If there's a large region of black, they can dim or disable the LEDs behind that region and save power.

[Green Xenon]

This isn't necessarily true with LED-backlit LCD TVs. If there's a large region of black, they can dim or disable the LEDs behind that region and save power.

 

 

1. Are most LED-backlit LCDs designed to do what you stated?

 

2. Even if they were, wouldn't the theoretical purely-LED screen I described still be more energy efficient than the currently-available LED-backlit LCDs?

[Cap'n Refsmmat]

1. I don't know about "most," but they are moving toward it to achieve better contrast and power efficiency.
2. It's not actually theoretical: what you've described is an OLED display. The linked article also discusses some of the disadvantages of the technology.

[Green Xenon]

1. I don't know about "most," but they are moving toward it to achieve better contrast and power efficiency.
2. It's not actually theoretical: what you've described is an OLED display. The linked article also discusses some of the disadvantages of the technology.

 

 

Just out of curiosity, why does the display use OLED as opposed to regular LED?

[Cap'n Refsmmat]

It uses organic compounds to form an LED. That's the only difference; regular LEDs use inorganic semiconductors.

[John Cuthber]

You can get a display based on leds from here

http://www.eurodisplay.com/LED-screen-how-it-works.asp

No doubt others are available too.

[Green Xenon]

You can get a display based on leds from here

http://www.eurodisplay.com/LED-screen-how-it-works.asp

No doubt others are available too.

 

Any of them for indoor use?

[Green Xenon]

It uses organic compounds to form an LED. That's the only difference; regular LEDs use inorganic semiconductors.

 

Ok but what is the advantage of using organic as opposed to inorganic?

[Cap'n Refsmmat]

I don't think current inorganic LEDs are small enough to make a screen, apart from a very large one (Jumbotron-style).

[agentrnge]

Agree on size issues with LED pixels. You need to fit at least 300 ( 100 r/g/b) per inch for a monitor, and maybe 50-100 per inch for a larger tv. +1 what the Cap'n says. They have used LED subpixel displays for years for -very- large -very- bright outdoor displays/billboards/timesquare/sports arenas and the likes. Positives: probably-possibly blindingly bright; likely very good viewing from a wide range of angles.

 

Most cheap LEDs tend to pulse at 60hz, but that might just be a function of being a cheap LED with no special electronics in between and being driven by a 60hz power feed ( think Christmas light LEDs )

 

I am not sure how well all LEDs handle variable intensity. You might end up with an emitter unit that can only appear to be a few discrete levels of intensity, and none below a threshold to turn the LED on. I am not even close to an expert on these things. Just noting observations of LEDs i have seen in the past.

 

Also agree that LCD tvs generally suck. The seething masses have spoken and keep buying them more than anything else tho.

Plasmas are pretty sweet, and reasonable cheap now. I still like my LED/DLP rear projection the best tho.

[John Cuthber]

The light emitted by a LED is close to linearly proportional to the current through it. Much more nearly proportional than the case with a "classic" CRT.

LEDs are used as modulated light sources. The 60Hz pulsing is, if anything, proof that they can be switched fast enough to provide a moving picture display. It arises from the power supply and wouldn't be an issue in a display.

[Xittenn]

ROHMS series PicoLED is still going to present a dot pitch >1mm( note: 1 LED can produce RGB but is sized 1mm and would have to be tightly packaged side by side.) The average dot pitch of most displays is ~0.25mm! Despite progress made it is still rather insufficient, although as seen within the link applications are being found.

 

I was hoping to see a marked increase in display resolution back in the early 90s but really, for computers at least, the available resolutions have not changed despite the ever increasing video card output capabilities. It would really suck to downgrade in the name of solid state LED displays just for the sake of doing so :/

Edited January 16, 2011 by Xittenn

[Green Xenon]

Also agree that LCD tvs generally suck. Plasmas are pretty sweet, and reasonable cheap now.

 

Plasmas use up a lot more power than LCDs. As an eco-friendly consumer, I'd definitely take LCDs over plasmas.

[agentrnge]

Its not a significant difference so long as your not vegetating in front of the TV for 8 hours a day. I got my large display for movies and a show here and there. I'm very energy conscious... My DLP/LED @63" only draws about 200 watts on and just 1 when off. And its only on maybe 10 hours a week.

 

And either way I still cant stand LCDs for movies. They do a lousy job of presenting a film-look to movies. And they so an even lousier job of displaying non-native resolution content.

 

</lol_off_topic.>

[Ethereally Luminous]

Those organicLED's are beautiful

[Green Xenon]

Those organicLED's are beautiful

 

I yearn for the day when each subpixel of a monitor is an individual inorganic LED and compatible with indoor use. Most current inorganic LED displays are for outdoor use.

 

Its not a significant difference so long as your not vegetating in front of the TV for 8 hours a day. I got my large display for movies and a show here and there. I'm very energy conscious... My DLP/LED @63" only draws about 200 watts on and just 1 when off. And its only on maybe 10 hours a week.

 

And either way I still cant stand LCDs for movies. They do a lousy job of presenting a film-look to movies. And they so an even lousier job of displaying non-native resolution content.

 

</lol_off_topic.>

 

For still images -- such as most office work [majority of which is text-based] -- LCDs clobber plasmas. For movies, however, you're absolutely right. LCDs just aren't meant for hi-speed movement of images.

 

On the other hand, an indoor-compatible screen [in which each subpixel is an inorganic LED] is my dream display. ILED massacres OLED, LCDs, and plasmas.