MIT engineers are making vertical micro-LEDs for next-generation displays and VR goggles

[Alfonso Maruccia]

Forward-looking: An international team of scientists led by MIT engineers developed a way to make defect-free micro-LED wafers using a vertical approach that could pave the way for a new generation of virtual reality displays.

The vertically stacked micro-LEDs could provide a higher pixel density while being much easier and cheaper to manufacture, making them a boon for virtual reality devices where low pixel density and the annoying "screen door effect" are long-lasting issues.

Traditional displays use light emitting diodes arranged side-by-side, with red, blue and green sub-pixels packed as tightly as possible. Just like with transistors in a CPU, this side-by-side arrangement is quickly reaching its theoretical density limit, forcing researchers to find innovative solutions to keep pushing pixel density higher.

Micro-LEDs are another potential solution. They are made from inorganic, semiconducting materials which are one-hundredth the size of conventional LEDs and can offer better performance, require less energy and last longer than OLED. Conversely, they require a much more accurate manufacturing process to perfectly align the sub-pixels in the traditional RGB configuration.

Jeehwan Kim and Jiho Shin, the two MIT researchers leading the study published in Nature, have designed a new way to make micro-LEDs that wouldn't require the same extreme accuracy. They were able to grow and stack ultrathin membranes of red, green and blue LEDs in a vertical configuration, with each vertical pixel measuring just four microns wide.

By using a vertical stacking configuration, Shin said, the pixel area could theoretically be reduced "by a third." The vertical micro-LEDs can achieve a density of more than 5,000 pixels per inch, which is the highest reported to date. "Vertical pixellation is the way to go for higher-resolution displays in a smaller footprint," the researchers said, paving the way for virtual reality experiences that are indistinguishable from reality.

The scientists were able to get their vertical pixels thanks to a previously developed method to grow and peel away perfect, two-dimensional material from wafers of silicon and other surfaces, a process which they called "2D material-based layer transfer" or 2DLT.

They also demonstrated how to stimulate an individual vertical structure to produce the full commercial spectrum of colors, but they now need to develop an active matrix system capable of controlling "25 million LEDs separately."

Permalink to story.

https://www.techspot.com/news/97507-mit-engineers-making-vertical-micro-leds-next-generation.html

 

[Thatsdisgusting]

Maybe show us planar microLEDs on the shelves first?

 

[wiyosaya]

Maybe show us planar microLEDs on the shelves first?

There are a few out there, but they are very expensive. https://www.microled-info.com/

If this brings the price down and gets displays based on micro-LEDs to market at substantially lower prices, I'll be happy.

 

[Thatsdisgusting]

There are a few out there, but they are very expensive. https://www.microled-info.com/

If this brings the price down and gets displays based on micro-LEDs to market at substantially lower prices, I'll be happy.

Yea, that's the only logical explanation why this might be actually interesting, looks like every advanced modern tech needs alot of tweaking, improving and maturing before going en masse. I don't know though if it is neccessity in each and every case, or it's just engineers trying to outsmart and convince marketologists, CEOs and shareholders that "we should move to this new tech and leave milking folks with decades old LEDs and OLEDs."

 

[kiwigraeme]

"but they now need to develop an active matrix system capable of controlling "25 million LEDs separately." "

there's an article right there - ie how do you light up individual pixels on an 8K display - CRT , Laser projectors - scanning seems straight forward - is it some kind of voltage/resistor magic ??on a wired grid below ??

 

[wiyosaya]

Yea, that's the only logical explanation why this might be actually interesting, looks like every advanced modern tech needs alot of tweaking, improving and maturing before going en masse. I don't know though if it is neccessity in each and every case, or it's just engineers trying to outsmart and convince marketologists, CEOs and shareholders that "we should move to this new tech and leave milking folks with decades old LEDs and OLEDs."

Unfortunately, it may be a chicken-egg type scenario. If this tech had come along before OLED, OLED might never have been developed. As I see it, old LED tech is nothing like this, though.

I've not yet gone OLED, but plan to if microLED is not within my price range by the time I am ready to buy. I've got my price points, and basically, if/when microLED prices come down at least to the current OLED prices, I might be willing to make that jump since microLED has fewer, if any, drawbacks compared to OLED.

 

[wiyosaya]

"but they now need to develop an active matrix system capable of controlling "25 million LEDs separately." "

there's an article right there - ie how do you light up individual pixels on an 8K display - CRT , Laser projectors - scanning seems straight forward - is it some kind of voltage/resistor magic ??on a wired grid below ??

Yes. Part of the expense of the current incarnation of microLED comes from the need to accurately place the LEDs on such a grid - given that they need separate R, G, and B leds on the grid. As far as I understand it, it is a wired grid.

 

[Mr Majestyk]

Maybe show us planar microLEDs on the shelves first?

Why? The cost of traditional microleds is huge because you now need lithography to produce them. microled screens will be far more expensive than OLED and IMO not worth the price for the average consumer. This breakthrough could mean massive price reductions, but I couldn't cvare less about VR, let's see it come to traditional screens.

 

[bviktor]

Density would be easy if manufacturers stopped chasing their pointless 8K (=high margin) dreams. No sane person needs a resolution that's above the capabilities of the human eye. Soooo... give us 4K?

Boom! Just reduced your density requirements by 75%. You're welcome.

 

[Mr Majestyk]

Density would be easy if manufacturers stopped chasing their pointless 8K (=high margin) dreams. No sane person needs a resolution that's above the capabilities of the human eye. Soooo... give us 4K?

Boom! Just reduced your density requirements by 75%. You're welcome.

It depends on viewing distance and screen size. 100" TV's are not far off. I would prefer 8K for such a size, not that I have any interest in such an enormous TV even if cost or power usage weren't the problem, but plenty of people seem to want bigger and bigger TV's. Still the next logical step should be 6K not 8K.

 

[Kotters]

Density would be easy if manufacturers stopped chasing their pointless 8K (=high margin) dreams. No sane person needs a resolution that's above the capabilities of the human eye. Soooo... give us 4K?

Boom! Just reduced your density requirements by 75%. You're welcome.

There's far more to human visual acuity than simply the ability to distinguish individual pixels. Even beyond "retinal" density the human eye can pick up additonal detail.

 

[grumblguts]

So instead of the light from the OLED coming directly out it has to pass through 3 layers of membrane that will effect its brightness. what a stupid idea

 

[wiyosaya]

So instead of the light from the OLED coming directly out it has to pass through 3 layers of membrane that will effect its brightness.

Each individual R, G, and B LED is an emitter of light just like a "dot" of OLED ink in an OLED display and the phosphor "dot" in a CRT or phosphor cell in a Plasma display. micro-LED is a true emissive technology, and is predicted to not be subject to "burn-in" problems of CRTs, Plasma displays, or W-OLED displays.

The technology you are describing sounds like LCD where the light is essentially filtered by the LCD. There is no equivalent in micro-LED displays. There is something similar, as I understand it, in LG's W-OLED - where the "W" stands for white, where the filter is needed to render colors. Samsung's Quantum Dot OLEDs also do not have a filter, as I understand it - someone correct me if I am wrong about Samsung's QD-OLED displays.

Here's a good explanation of how micro-LED works.

 

[bviktor]

It depends on viewing distance and screen size. 100" TV's are not far off. I would prefer 8K for such a size, not that I have any interest in such an enormous TV even if cost or power usage weren't the problem, but plenty of people seem to want bigger and bigger TV's. Still the next logical step should be 6K not 8K.

A 100" TV isn't practical in 99.99% of homes. They can "want" it, but won't get such a TV anyway. Even my 65" is a monstrosity and a pain to relocate and stuff.

 

[bviktor]

There's far more to human visual acuity than simply the ability to distinguish individual pixels.

Such as?

 

[Endymio]

A 100" TV isn't practical in 99.99% of homes.

99.99% of Internet statistics are made up on the spot. Homes grow larger all the time. Compared to 1970, the average home today is 1,000 sq. ft. larger. Most newer homes can hold a TV that's 7 foot wide.

 

[bviktor]

99.99% of Internet statistics are made up on the spot. Homes grow larger all the time. Compared to 1970, the average home today is 1,000 sq. ft. larger. Most newer homes can hold a TV that's 7 foot wide.

I have no idea how big 1000 sq ft is, or how long "7 foot" are. I don't care either, I might add.

A big wall doesn't imply it is practical to put a 100" TV in it. You can't put any furniture beside that wall, and you can't put anything between the TV and the couch either. Rearranging the room becomes next to impossible too, due to the sizes and constraints involved.

If you're really saying we can expect TV sizes to grow infinitely, I beg to disagree. There's a limit to everything.

I know Americans love to supersize everything, but I don't quite understand the point of watching a movie from 8 meters on a 100" TV instead of watching it from 4 meters on a 65" TV and have the same effect. And have a big empty space in your room where you literally can't put anything between the TV and the couch, because it'd be blocking the view.

The other option is to keep the TV at the same distance and keep turning your head and rolling your eyes all the time, because the TV is simply bigger than your eyes' field of view. Again, it makes absolutely no sense whatsoever.

But then again, I'm just a dumb European, I don't understand most of the American supersizing idiocracy in the first place, so they might go for it anyway.

 

[wiyosaya]

I have no idea how big 1000 sq ft is, or how long "7 foot" are. I don't care either, I might add.

A big wall doesn't imply it is practical to put a 100" TV in it. You can't put any furniture beside that wall, and you can't put anything between the TV and the couch either. Rearranging the room becomes next to impossible too, due to the sizes and constraints involved.

If you're really saying we can expect TV sizes to grow infinitely, I beg to disagree. There's a limit to everything.

I know Americans love to supersize everything, but I don't quite understand the point of watching a movie from 8 meters on a 100" TV instead of watching it from 4 meters on a 65" TV and have the same effect. And have a big empty space in your room where you literally can't put anything between the TV and the couch, because it'd be blocking the view.

The other option is to keep the TV at the same distance and keep turning your head and rolling your eyes all the time, because the TV is simply bigger than your eyes' field of view. Again, it makes absolutely no sense whatsoever.

But then again, I'm just a dumb European, I don't understand most of the American supersizing idiocracy in the first place, so they might go for it anyway.

I don't think it is exclusive to the US or Europe. I think its a couple of things.

Display technology has changed. In the CRT days, displays of this size were basically impossible. Picture tubes this size would have had substantial weight and also, the fact that they needed to be under vacuum would have put substantial stresses on the glass. Now, with flat panels, the size limitations are gone, and there is no stress from having to be under vacuum - not to mention, projectors have always been capable of displaying a picture far bigger than a CRT could. So, manufacturers have, essentially, no limit to the size of the display that they can make. I doubt manufacturers care about anything other than making a profit. As long as there is someone out there willing to buy whatever they produce, the manufacturer will be happy because they are making a profit.

Some people have a considerable amount of disposable income in this day and age, and it is not only US citizens. There's Chinese and Indian citizens to name just a few. It is precisely those people that manufacturers want buying their products because the average person cannot afford them, and without those people with large disposable incomes, manufacturers would not be able to sell products priced in the range of these current displays. That's not to say that prices will not come down. As with any new technology, prices on these huge sets will drop as the technology matures. In part, that people with these disposable incomes spend money on these new technologies helps, in the long-term, to bring the prices of new technologies down to where average people can afford them if they want them. Not everyone wants them, though.

It is also those people with a considerable amount of disposable income that are likely to have enough space in their home to put one of these displays.If you have a look at this - https://www.avsforum.com/forums/#home-entertainment-theater-builder.3 you'll see people with a considerable amount of disposable income who have built some dedicated, and large, home theaters. I am willing to bet that most display manufacturers that manufacture large displays would love to sell anyone of those people a display.

That's not to say that everyone has a considerable amount of disposable income. Obviously, they don't. Its an elite market for lack of better words, and there will always be manufacturers eager to separate those in that market from their money.

 

[TazR6]

I have no idea how big 1000 sq ft is, or how long "7 foot" are. I don't care either, I might add.

A big wall doesn't imply it is practical to put a 100" TV in it. You can't put any furniture beside that wall, and you can't put anything between the TV and the couch either. Rearranging the room becomes next to impossible too, due to the sizes and constraints involved.

If you're really saying we can expect TV sizes to grow infinitely, I beg to disagree. There's a limit to everything.

I know Americans love to supersize everything, but I don't quite understand the point of watching a movie from 8 meters on a 100" TV instead of watching it from 4 meters on a 65" TV and have the same effect. And have a big empty space in your room where you literally can't put anything between the TV and the couch, because it'd be blocking the view.

The other option is to keep the TV at the same distance and keep turning your head and rolling your eyes all the time, because the TV is simply bigger than your eyes' field of view. Again, it makes absolutely no sense whatsoever.

But then again, I'm just a dumb European, I don't understand most of the American supersizing idiocracy in the first place, so they might go for it anyway.

You seem to know what 8 foot 4 inches is, though.

 

[Endymio]

The other option is to keep the TV at the same distance and keep turning your head and rolling your eyes all the time

Do you turn your head and roll your eyes constantly when viewing the real world, which encompasses a full 360 degrees?

Some math: a 100" TV at your stated distance of 4 meters covers a 37 degree FOV. The human FOV without eye movements exceeds 120 degrees. So much for that argument.

I don't understand most of the American supersizing idiocracy in the first place, so they might go for it anyway.

From someone who spent 1/3 of my life as the citizen of another nation, and much of the rest abroad, usually in Europe, I'll tell you a dirty secret. Europeans love big TVs, big cars, and big houses as much as anyone. They just can't afford them as often.