LG Patents VR Display For ‘Alleviating Screen-Door Effect’

by Jamie Feltham • September 18th, 2017

Current displays for VR headsets allow us to peer into virtual worlds with ease, but there’s plenty of room for improvement. According to a recently discovered patent, LG is taking aim at one of those areas; the dreaded screen-door effect.

The patent, which was published last week, details a display that is “capable of alleviating a screen-door effect,” thus improving image quality inside VR.

Screen-door effect relates to being able to see the gaps between pixels in a VR headset’s display, which is magnified by the pair of lenses you peer through. Higher-resolution displays with increased pixel density can improve upon this issue; a 4K image will be much clearer than, say what’s on offer with the 1080p display inside PlayStation VR, though even then there’s still a long way to go before images reach a retinal resolution.

It doesn’t sound like LG’s new display targets resolution, though. Instead, the patent describes a “light diffusion member” that is placed between the display panel and the lenses. In the patent’s words, this “diffuses light emitted from a light-transmitting area of a display panel to a light-blocking area of the display panel” and “improves the image quality of the display.”

Whatever LG is working on, it’s possible that this design will be implemented into its upcoming SteamVR headset, which recently resurfaced for the first time in six months. We don’t know when the headset is set for release right now, but we’ll be very interested to take another look at it if it really is able to cut down on screen-door effect.

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  • NooYawker

    Getting rid of the screen door effect is a HUGE step. 4k, larger FOV’s mean nothing if you have that screen door effect.

    • Rigelleo

      If you increase the number of pixels at the same FOV to a certain value you do not have an SDE, this is because the angular dimension of the spaces between pixels will be lower than the limit of resolution of your eye. Solutions such as this of LG are useful only for the actual low resolution of the HMD we have today.

      • JMB

        Could you please explain how LG’s patent works exactly? I don’t think I have quite grasped it yet.

        • David Poore

          sounds like it just makes the light from each pixel bleed just enough that it covers the gap between the pixels.
          id be concerned that if hte headset gets hit by something (say, by your own motion controller…cough cough vive im lookin at you), that it could knock it out of wack or something.

      • G-man

        except the size of the gap between pixels doesnt just get smaller because there are smaller pixels, the gaps could be just as wide, then a higher resolution would look no better and could even look worse for sde. the only improvement to sde is if they make the gaps smaller.

        • Rigelleo

          Okay, but at some point if you increase the number of pixels at the same FOV, you reduce the angular dimension of space between pixels, even if pixels become point-like, the human eye sees point-like objects as a point spread function. Therefore there is a minimum resolution value beyond which the SDE is no longer a problem regardless of the pixel size. That’s why you do not have SDE when you watch your monitor or TV

          • G-man

            all i’m saying is manufacturers are going to have to consciously make some effort to make the inter pixel gaps smaller for panels made for vr and pay attention to the pixel arrangement. if they just cram more pixels in in the same way they would for a phone panel then the screen door effect will be there it will just look different. until the point where our eyes cant see thing that small sure. but you are talking about teach thats like 5 years away at least to get the kind of resolution where we cant see individual pixels. long before that point we could fix the screen door effect at lower resolutions.

          • Rigelleo

            No. Think about it: if you play a videogame in a low resolution tv you see the aliasing (the individual pixels) but you don’t see the screen door effect. I bet that if we will double the linear resolution (from 1080×1200 to 2160×2400) we will have zero SDE regardless the type of display but we will still see a bit of aliasing.

          • G-man

            jesus christ. the tv isn’t strapped to your head. you don’t see a screen door effect for two reasons. the screen isn’t moving when you move your head. the 2d game image on the screen is coming from the exact same location as the gaps in the pixels. whereas a 3d stereoscopic image your eyes are trying to focus on as though it exists at a distance beyond the screen means the gaps are in focus at the screen distance. so your eyes are able to focus on them rather than the game, making it distracting to be able to focus on something that seems to be a screen covering a visor over your view, making it look like you are looking at another world through a pair of goggles with a wire mesh over them.
            if you cant see the gaps in the pixels on your tv then your tv is either too far away or high resolution enough. Right now i have a 4k 65 inch tv that i’m looking a from about 6 feet away and i can’t see the pixels, but it’s not even covering half of my field of view. and my last tv, a 1080p screen i could see the pixel gaps. and because a tv screen pixel gap size is different from a phone screen pixel gap size, even if i was looking at a 4k phone screen through a lens to make it appear the same size and distance as my tv i would see thos gaps because they would be proportional bigger than the gaps on the tv pixels. the resolution on the vr headset screens would need to be more like 8k per eye before we get close to the resolution itself removing the potential for screen door effect. (the pimax headset is 4k per eye and reviews of that report there is still a screen door effect) OR. the manufacturers could work on intentionally reducing the gap size and not have to have that resolution to nullify the screen door effect.

            but the most important part, is pleae, stop trying to talk about this like you know what you are talking about. you don’t, you’re just talking out of your arse.

          • Rigelleo

            1) I’m an optical engineer, I work in optical metrology i know what i’m talking about. 2) Did you try to look at a VR viewer with a closed eye? Can you explain to me what is the difference between watching this and a TV? That’s exactly the same thing. If I approach my eyes to my full HD hd, first start to see the aliasing, only after, when I have eyes much closer to the TV I also start to see the SDE 3) The fact is that you’re telling me that the ratio between the pixels gap and the pixel size of a VR (or smartphone) screen is larger than that of a regular TV. I deny this very statement.

    • Shawn Blais Skinner

      You won’t have SDE with a 4k display period, even if it’s just upscaled. You might still have aliasing/pixelation, but not SDE.

      • Wassoll Das

        Not only “might”, you will definately have aliasing/pixelation with 4K.

        4K per eye is like 27 inch monitor @ 1080p in arms lengh distance. Wich means, its not perfect yet, but in the range that some PC gamers are used to. People who use a Gaming laptop to play are used to a quality that equals about 6K per eye.

        The resolution of the human eye is reached if one has 12K per eye @ the same FOV like a Vive or Rift, wich is why some people say, the final resolution for HMDs will be 16K per eye. Others claim, most people will not see a difference between (8K per eye and 16K per eye, if the content is photorealistic. If its high contrast stuff like black lines on white background, its a different matter where 8K could still look a little bit pixelated.

        • Shawn Blais Skinner

          I was mainly referring to whether it was upscaled or not. I find that using a Super Sampling rate of around 2.0 remove almost all pixelation and aliasing for my eyes. That’s an effective resolution of around 3k per eye, and seems to do the trick. My guess is 4k per eye, if rendered natively, would be almost perfect.

          • Wassoll Das

            I explained it already.

            Native 4K per eye does NOT “do the trick”.
            4K is extremely better than the current 1K per eye, but its comparable to a traditional PC gaming experience with a slightly too large screen.

            2K upscaled to 4K is 960×540 upscaled to 1920×1080 watched on a slightly too large screen.

            natively its just 1080p on a slightly too large screen. Wich is causing you to see pixelation. Wich I know, because I type these lines with a setup that causes the same “Pixel per degree” as native 4K in a 110 degrees FOV would have.

            EDIT:

            resolution of the eye is 120 pixels per degree FOV btw.

          • Shawn Blais Skinner

            Ya an I understood you the first time, I just completely disagree. Aliasing and SDE are two different issues. IMO a display resolution of 4k per eye would effectively solve SDE (by effectively, I mean for 99% of users, not the technical definition according to the biology of your eyes). In terms of eliminating aliasing, a rendering resolution of around 2k / eye seems to be enough to eliminate the vast majority of them, based on my personal experience in SteamVR, it’s very limited returns after 2.0.

          • Wassoll Das

            Just pops into my eye. What has “Supersampling” to do with that?
            Supersampling doesnt increase the displayed resolution at all.

            It increases the rendered resolution, but the image is downsized to the displays native resolution. The effect is basicly improving the efficiency, in wich the existing pixels are used to display information (by using information smaller then 1 pixel to influence the colors of the existing pixels)

          • Shawn Blais Skinner

            Because pixelation/jagginess is mostly from low-resolution rendering, if an image is super sampled and downscaled, that will effectively eliminate the jaggies. Screendoor effect is another issue entirely.

        • MowTin

          I’m looking at two 27 inch monitors at arms length as I type and I can’t see any pixels.

          • Wassoll Das

            Bad eyes? Doctor told me I have 120% view, but you should see pixels. πŸ˜‰

            I can even the the monitor mask on on the white backgrond right now.

      • DeeHawk

        This is not true. The Pimax4K still suffers from SDE. Like Wassoll said, not even 4k is that good so close to your eyes.

        • JustNiz

          >> The Pimax4K still suffers from SDE
          Apaprently, but at least partly because it also has a much wider FOV, so the number of pixels per inch is actually nothing like twice that of a Vive.

          • Shawn Blais Skinner

            Well reviews of that state that SDE is almost in-perceivable, and significantly better than Rift/Vive, so I think the statement is effectively true, if not technically. But also, realize that this is not 4k/eye, it’s 4k divided across both eyes (2k x 2k for each eye). If it was truly 4k on each eye it probably would go from barely perceivable, to not at all.

          • Mr. New Vegas

            Its actual 4K, they use 2 4K screens.
            They even offer 8K HMD, with 2 display port connectors, one for each display

          • DeeHawk

            You might just be right, then. Didn’t know Pimax ‘cheated’ in their naming of products, that went right over my head. I have no doubt that SDE is better with better resolution, but I’m still a little skeptical that 4K will be enough without some sort of technology like the one in the article. Mainly because I use my Vive daily, and SDE is super obvious within single color areas. (in photographic images it’s much better). Compact it x4, and I still believe I could see SDE on single colors.

      • G-man

        thats nonsense. you could have a 4k screen with huge black gaps between pixels and it would look awful. the only way the screen door effect is fixed is when the gaps are so small that no ones eyes are able to see them.

        • JustNiz

          Not really. if you’ve got a 4k pixel wide screen (i.e 2x the horizontal pixels as what the Vive display is now) then you also have 2x the gaps. That means to have a 4k screen and keep the same physical panel size, the gaps literally can’t be as wide as what we have now.

          • G-man

            they dont have to be as wide as they are now. since you have more pixels you have more gaps. if the overall area of gaps is increased then the screen door effect will look worse until you reach the point that the gaps are small enough that we can’t see them. the amount of pixels has no direct effect on the size of the gaps between the pixels.

        • Shawn Blais Skinner

          No unless your display was 10m wide you couldn’t… how are you going to fit 2000 pixels with “huge gaps” in a 3″ x 3″ display? All these displays are a similar physical size, meaning when you pack in more pixels, they must all get smaller and harder to distinguish, gaps and all.

    • JustNiz

      Yes but for properly good image quality they need to GET RID of it, not just blur it (and everything else) out after the fact.

    • Whatever LG is working on, it’s possible that this design will be implemented into its upcoming SteamVR headset,

  • Firestorm185

    Interesting! A light bleeding technique. Pretty cool!

  • dk

    greeeeeeeat now also use 1600by1600 display per eye

  • wheeler

    Can’t wait to see what they have under wraps. I’m itching for an HMD upgrade.

    • RFC_VR

      LG always have great tech. I’ve owned a number of their displays for home cinema, TV and gaming on pc with excellent results.

      LG steamVR hmd looks real interesting, rumours of delays due to wireless and display upgrade 😘

      • Shawn Blais Skinner

        Rumors from where?

  • mellott124

    HMDs have had diffusing filters in the past. I wonder how this is different. OSVR HDK2 has one currently too.

  • Shawn Blais Skinner

    Sounds like what PSVR is already doing, which creates that odd scratched-lens effect.

    • DeeHawk

      If someone else already invented/uses the technology, they can’t patent it. Wait and see before you judge.

      • Shawn Blais Skinner

        No judging, just an observation that it sounds similar to what Sony did with PSVR. Thats not a good or bad thing, just interesting imo.

  • JustNiz

    Light diffusion? …so basically a layer of translucent material that will blur out screendoor but also make edges and everything else blurry. You might as well just defocus the lenses. Not innovative and not worth a patent.

  • nargorn

    Interesting, but nowhere mentioning about Pimax 8k launch on kickstarter? Maybe interesting too..;)

  • john orsis

    obviously LG can’t get a valuable patent in this area just because all yummy features has been already patented by leading competitors: Microsoft, Samsung, Oculus, HTC.. LG is a catch-uper. i would love to see a technology from LG which offers a reduced sde but currently LG has no significant R&D here, just search uspto or espacenet for patent info