DIY Dual-Layer LCD monitor - can it match OLED?? 

🥦 Let's hear it for the random broccoli

I'm just amazed how accurately you were able to align the two LCDs

If I remember correctly, Hisense has done this in one of their TVs. They achieved incredible contrast levels by using a second monochrome LCD layer to provide those inky blacks. Sadly, I don't think they've pursued it any further, synchronizing the LCD layers was quite difficult.

If you fed both screens different HDMI signals, like in a "mirrored" dual monitor computer setup (using two outputs from your graphic card), you'd be able to adjust both layers individually. This could help making the picture's colours less "poppy" and maybe even help increase the white levels.

Something you didn't mention is that you have essentially doubled the display's gamma by multiplying all colors by themselves. Most displays have a built-in gamma of 2.2, but this raises that to around 4.4. You should be able to compensate by halving the gamma in software or in the monitor's settings, which will give you more accurate colors and fix over-saturation.

I would love to see a V2 version of this where you dissemble the panels further and experiment with various filter layers.

Professional dual layer LCD monitors use a monochrome LCD as the rear panel, which is better for light to pass through, thus increasing the efficiency (though it is still significant less efficient than a single layer LCD). Also, with your method, you are significantly increasing the saturation, so you would need to get a calibration device to counter that. Still, this is a really cool project!

To deal with the polarization problem, you can put a sheet of polarizing material between the 2 screens at a 45 degree angle to the polarization. This will "turn" the polarization without the need for diffusion. Another option: buy 2 SQUARE monitors. Assemble the screens a quarter-turn from one another. Run software to quarter-turn the images so they align.

I think you could actually add a middle polarization layer between the other two. Weirdly, if the middle layer is at an angle between the other two, it allows light to pass through all three. I think this would actually allow more of the original light through than paper.

i think removing the polarisation filter from the back lcd will help with brightness and eliminate the need of the tracing paper, you can then also bind both of the screens with uv glue used for screens, so there will be less blooming and blurryness in text

ah yes, built in anti aliasing

One year later, Apple did similar things on their iPad.

One thing I think you might have missed is the gamma. Monitors are non-linear with respect to their input, and there is typically a compensation curve (gamma) to fix that. However, with two screens, your nonlinearity will be doubled and you will need to adjust your gamma curve (easily accessible in desktop OSs).

This is a project that I think deserves a version 2. You might get better results with different panel technologies (like TN VN and IPS), or you might be able to dig and find better solutions for diffusion, polarization, backlighting and driving the displays. Even if the final result is expensive and impractical I think it's worth it to see just how much is possible by going full DIY.

You always come up with the most fascinating ideas. They aren't always practical, but the attention to detail you put in makes almost every build you do a piece of art.

Awesome project! Adding a third polarized film that is perpendicular to the tv polarized film would allow you to see the image again and would probably be less fuzzy that trace paper. The other option is to remove the polarized film on the back panel.

would be pretty interesting to test the optimised final version with an screen calibration tool, just to see actual numbers of things like nits, peak brigtness, color saturation, gamut, etc...and compare them with standard monitors

Love seeing these diy projects that compete with hardware 10x the price

I thoroughly enjoy your channel buddy and have for years. The things you do and make are phenomenal. You're extremely talented. Great work

This guy is great…every time I have that question lingering in my mind as he’s showing it, he immediately give the explanation or reason for how something works for his projects. Like he reads our thoughts. Great informative video. Wish I had the resources and time to make one myself. I’d want to try this on some older cheap lcd tvs

Over ten years ago, students at RIT combined an Apple Cinema Display panel with a pair of projectors that, combined, matched the resolution of the display. The projectors projected the image in black and white behind the LCD panel displaying the same image in color. There were some off-axis alignment issues, but the first look at what HDR would eventually look like was stunning at the time.

I would’ve loved to see a comparison between this and OLED. Would be cool to see the difference in black levels and persistence blur.

It's nice to see a typical diy perk again. I like these relatively simple diy ideas

I came up with this idea myself a couple of years ago when I found out about how LED TVs with array backlights work, glad to see you tried it and that I was onto something!

Removing the polarizing layer would probably yield much better results, but I know it would be far harder to do without damaging the LCD. It would be cool to see you do it though, as I think you have the skills to do so.

Awesome project! You could try use a half-waveplate instead of the tracing paper. This should more than double the brightness of the monitor. It's a clear film that rotates the polarisation axis by 90°. Right now, half the light is absorbed by the second monitor's polarising filter because the polarisation is random. Really nice work though. Looks amazing 👏

Your work is amazing! Congratulations on perception, execution and presentation!

absolutely love your videos and the way you explain things, good job!

This is quite similar to something that was done (very successfully) at the computer science lab at my university. Rather than using two LCD panels, they used a DLP projector as the backlight for one panel.

Very cool project Matt, even though this one isn't very practical as pulling 250W constantly for a monitor will easily offset just buying a more expensive monitor in the long term it's always fun seeing your ingenuity!

Your videos are like Aroma therapy for people in the Tech world. its so calming to watch your videos that my concentration doesn't break until you say the outro. Love your work Matt!

videos like this are the reason i m subbed to you since 3 years now !! Keep it up brother !!

One thing you could try to improve brightness and sharpness is removing the polarizers instead of unpolarizing the light. Just doing that should double the brightness, as 50% of unpolarized light is absorbed by a polarizer. The only problem is that it’s difficult to do without breaking the panel, but it’s doable.

Congratulations, you are getting more and more creative with every single video you upload. I am satisfied to live in the same decade with you😁

this gave me a more intricate look at a monitor than I ever thought I'd be seeing. So I thank you for that alone. Gave me a much better idea of how these work.

I really LOVE the way you change ORGINAL things into awesome stuff 👍🏻👍🏻👍🏻👍🏻👍🏻

As a multimedia computing graduate, this project is simply priceless. Not just the project itself, but rather also understanding of the inner workings of a monitor. Throughout my four years of uni’ I’ve not once been explained that the LCD is taking advantage of polarisation to produce the images, as you’ve explained in very simple terms. I could not thank you enough.

Unlike any other channels, this channel project literally take time, effort and innovation. But that makes it even more special. We're always waiting for the next video to release. Great job as always.

This really needs a part two.

It is literally kind of a dimmer OLED but without any risk of burn-in 🔥 Really well made ! Great job man, your creations are incredible.

You just built one of my long standing tech-dream. Crazy guy you are! Thanks for tinkering around!

You are the modern inventor, DIY Perks. I'm struck by your creative brilliance in every video I watch.

Nice project! The reason you need the paper between the two panels is that they have the same filter orientation (same brand/model). A polarizer filter lets light through with either horizontal or vertical polarization. The way LCD works is: there's a liquid crystal (hence LCD) layer between two polarizer filters of opposite orientation. So, for example: a horizontal filter in the back, a vertical filter in the front. This blocks all light (except some bleeds through) but when you apply voltage to the liquid crystal it rotates the polarization by some angle proportional to the voltage. So if it turns the horizontally polarized light by 90 degrees, then all of it goes through the vertical filter in front. Now when you put the two panels on top, the front vertical filter of the first panel lets through only vertically polarized light, but the back horizontal filter of the second panel blocks that. As someone suggested, you could remove one polarizer filter from between the two panels, but another option is to just flip one panel and have its front (horizontal) filter face the other panels front (horizontal) filter, so they would let light through without the need of the paper. Of course you would need to flip the image on that panel by software somehow - not sure how hard it would be. Another thing that someone already mentioned is that the two panels on top basically multiply the brightness, so you get your brightness squared - need to adjust your gamma.

nice, this project went farther than I had expected 🙌 very well done 💪

Matt, I absolutely love your content. you're easily my favourite content criator on youtube. thank you for giving us the most professional, entertaining, educational stellar content every single time

I would love to know the results of a checkerboard contrast test before and after the DIY.

this result was unexpectedly interesting! I don't see much potential in this application in question, but rather its use in entry-level projectors, as the gain in contrast would allow the use of stronger light sources, bringing more luminosity and quality to these projectors! Send greetings to your Brazilian fans

This was one of my favorite videos from you!

This just makes me want to find a high refresh rate monitor with a busted backlight and just drop it on top of an overhead projector from the thrift store so I can finally have my high refresh rate projector I've wanted for years now. Seeing you do the disassembly and backlight design was inspiring and empowering! Excellent as always

Have you tried to remove the polarization layer on the first screen, like a lot of projects do to make "secret" screens that only show up when wearing polarizing glasses?

I have been sat here amazed by the performance of your creation, then I remembered that I have been watching it on my own traditional LCD monitor all along anyway lol. I would love to see something like this in person.

Thank you, Matt. Another cool project. Enjoyed the video.

OK, firstly, this is amazing, honestly, many kudos. And please make this a series, this can be improved vastly. On the top of my head a low res monochrome panel as the 2nd display or using controlled mini led for backlight, etc there's just too many possibilities. I cannot wait for more versions of this, Thank you.

We have panels like this on a lot of our casino floors! IGT made a unit called the G23MLD (Multi-Layer Display) that has 2 LCDs stuck together to achieve a 3D effect on the slot theme. Most of the time the reels are on the back monitor and the line indicators are the front monitor

NICE DIY project mann! Thank u :)

As always, brilliant video! Cheers!

You inspired me to turn two old laptops into a router and the other one is now a media PC thanks!

You amazingly and regularly come up with original projects. Keep up the good work!

that is incredibly impressive. well done that man.

Just brilliant! Well done!

great idea. I am stunned with the result of your experiment. if the problem is the dropshadow-like on letters especially during Ms task only, I suggest to make the lcds additional switch on and off so that if and whenever watching videos or gaming you can enable both lcds to take advantage the viewing performance and just disable the other lcds during light task only like Ms word.

There was a monitor that did this a while back and used a second black and white display to increase contrast without affecting colour balance. I think ltt did a video on it.

Best thinkering and diy from this channel!

Please go further with this one 🙏 it’s an amazing video.

Super cool project, I always wondered if it was possible to do this. How about removing the polarizing filter of the first panel instead of using tracing paper? I know that people have made those "privacy screens" from old LCD's that are only visible when wearing polarized sunglasses. Or is the film impossible to remove in these modern panels?

I've been wanting to build something like this ever since I saw coverage of a panel maker that was looking into something like this with a 4K main panel and a 1080p black and white panel to help control the backlight. I'm quite sad that it didn't work out, it definitely does seem worth it compared to the cost of higher end alternatives and the superiour amount of "local dimming zones". I would like to see you test the colour accuracy, as I prefer the image to be more accurate to being overly vibrant.

You've truly outdone yourself once again!

Love your videos man, very informative and entertaining

The right way to measure the convenience of "dual layerlcd" is to present an image like a chess board, 100% white squares along side 100% black squares. Then you measure the luminance with a luminance meter. A typical white luminance is about 80cd/m2, and a typical black luminance is about 2cd/m2. The contrast ratio is the white luminance/black luminance. A dual layer lcd is better than a regular lcd ONLY if the contrast ratio is greater in tje dual layer than in the regular lcd. You show us a darker black in the dual layer but also a brighter white in the regular lcd. We can say nothing without measuring contrast ratio.

Why not flip or rotate the second LCD to match the polarization? Also if you don't need all the contrast reduce the black-level on the second LCD to get some more light transmission

Brilliant project. Nicely done 👍🏽

Nice, you were 1 year ahead of Apple, who just did this on the new iPad Pro!

Super neat. I feel one aspect for improvement is calibration between the position of the two panels to narrow down some of that 'drop shadow' effect. I'm sure you could probably also get better LEDs for the backlight as well.

My solution for the polarization issue would've been to flip the image around for one of the panels, and literally flip the front panel over so its "incoming" polarizer and the "outgoing" one from the rear panel would match. But to be fair, I'm not sure how you'd make the monitor flip around... could fix it in software if you make both monitors show the same thing but flip one, most OSes allow that, right?

Wow you did an incredible job! Amazing!

Your channel is easily one of the best here

Really cool project! I use a eizo prominence for my work, and it’s my understanding that it uses dual LCD tech to get the black blacks. It would be really interesting to probe your monitor and see what the gamma curve looks like, from what I see in your video, It looks like it might be a bit steep (your mids look dark). Either way, excellent work!

Top notch content as usual👌🏽

Wonderful experience, thank you for the video

@DiyPerks Some people have mentioned rotating one of the displays so you can use one polarizer to increase brightness. You could use a custom VR type application where you could keep the two panels synchronized but have one image oriented one way, and the other another way. Instead of a left eye and right eye, the stereo image would render to the two seperate panels but be in sync with their own orientation that you would program into the Distortion shooter.. Make one of the layers monochrome, and that will also increase brightness

8:15 You can use a Optical Low Pass Filter to mitigate the Moiré effect.

I suspect that you could get a slightly crisper image by using more uniform commercially available diffusion films and optically transparent epoxy to bond all of the panels and the intermediary diffusion film together. I do appreciate how you went straight to replacing the entire backlight system with something substantially brighter, though doing so without needing to utilize several layers of commercial optical dispersion films with different dispersion patterns before using a standard frosted dispersion film to make it uniform does necessitate a deeper enclosure. I do think this is a topic worth revisiting at some point in the future to further refine the idea. Maybe with a couple of cheap 43" 4K televisions. If you have a decently deep desk, then a 43" television mounted to the wall behind it is a great monitor size for most applications. If possible, it would also be a good idea to just utilize an inexpensive HDMI splitter to duplicate the HDMI signal without relying on your GPU to keep the images perfectly syncronized. Ideally, you would want to find a way to drive both panels from the same driver board so that the signal is sent at the same time and there isn't a risk of clock drift between the driver boards. This would reduce ghosting. Unfortunately, it's unlikely that the driver board can provide enough current on its output pins to handle two panels in parallel.

I just found this channel a few days ago... i love it.

your channel really deserves its name!

Pretty neat, and very clever! The thickness bothers me 0%, it's still far lighter and thinner than many computers I've used in my life. But the increase in energy cost over time and the slight fuzziness are issues that i think would steer me away from making one

10:35 Dual LCD is not super energy consuming when you do it right! There are some LCD monitors out there that use only 35 Watts for a 4K 144Hz screen. For sure a manufacturer could make a HDR 1000 dual LCD for slight under 100 Watts. LCD always was superior than OLED, but for some reason the industry don't want to innovate on dual LCD monitors. Your example shows how close you can come with just some wet finger work, now put that same work to a nano meter precision. There is the answer, you can scale your model with an easy 100x in better picture quality while doing the same thing on a nano scale precision.

The best channel on RU-vid. Keep it up!

A great video from you, as usual! I liked it so much that I stayed tuned also for the advetisements part :). I still remember your artificial sun video; I will build one based on yours one day.

9:09 there's a lot of contrast, sure, but did you adjust gamma to 0.5 to compensate for the multiplying effect? With two displays both displaying 50% gray you actually get 25% gray (0.5 * 0.5 = 0.25). A gamma of 0.5 (effectively sqrt) brings that back up to the desired value.

After seeing the new iPads, I remembered I've seen it before. I did, from your video.

Great work! Very impressive.

I wonder if you could look into multi-layer 3D light field monitors. They use multiple LCD panels at a slight distance. Basically you can calculate how a certain light ray would move through the panels, and color their pixels accordingly. For example in this decade old paper: Tensor Displays: Compressive Light Field Synthesis using Multilayer Displays with Directional Backlighting

You should try this again but using SMD LED diffusers. They're a little plastic dome that just clips on over each LED to get the diffusion effect you are looking for instead of the tracing paper. Also, polarizing film isn't *that* expensive, changing the in-between layer for a sheet of that will likely give you even better contrast.

Pretty cool project Matt!! Watching the video on my OLED screen it looks pretty damn good.

v2 you can remove a polarization layer and have them stuck close together allowing for much better office workloads and should also make contrast better due to not having frosted layer between the lcds

Do you want to send it over for testing?

This is so cool Matt! Your projects never cease to amaze. Please revisit this one in the future, this has so much potential.

Your content is just great!

This is impressive! Thank you!!

He is an actual Genius