DIY Dual-Layer LCD monitor

Just this morning the algorithm served me up an ActionLab Short where James makes a "spy" LCD by removing the polarization layer from an LCD and installing the film into some glasses. https://youtube.com/shorts/jzY-N7V__fU

Seeing both of these on the same day has me wondering if you could run the setup with a single polarization layer in the front and completely remove the one on the rear screen? 

Posted by: @diyperks

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1. Please use polarizing film instead of tracing paper. By attaching polarizing film in the opposite direction to the first panel and allowing light to pass through, you may be able to effectively substitute tracing paper.

2. Additionally, use an HDR-capable HDMI splitter and a board with HDR on/off functionality. In LCD monitors, HDR works by extending the backlighting in the LC portion of the screen when HDR is turned on via the monitor's OSD. This allows for brighter representation of HDR content on LCD monitors that support HDR, although not to the same extent as OLED displays. However, dual-layer LCDs with enhanced contrast ratio should be capable of achieving true HDR. (Note that HDR needs to be enabled on each panel separately, which may be challenging if they have already been combined. In such cases, setting HDR to "Auto" in the monitor's OSD should suffice.)

3. Could you please try testing the backlight with the original monitor's backlight instead of a DIY solution? Since it's for general use and not for professional purposes, you may not require as many LED strips. Alternatively, adding one more line of the original monitor's backlight could be an option to consider.

There is a research paper, albeit somewhat old, that discusses some of the challenges of dual-layer LCD panels as well as solutions to those problems. It's called "Image splitting techniques for a dual layer high dynamic range LCD display" and can be found here: https://www.researchgate.net/publication/220050290_Image_splitting_techniques_for_a_dual_layer_high_dynamic_range_LCD_display_-_art_no_69170M.

Just remove the polarizing film from the bottom screen.

Posted by: @diyperks

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Some thoughts on making it brighter/more efficient would be to exclude the first diffusion layer (the one I fitted on top of the acrylic) as I actually don't think it's necessary when you consider that the second tracing paper layer (the depolarising layer) will do this diffusion anyway. Needs testing though.

 

Another idea is to rotate the polarised light rather than diffuse it. Surprisingly sticky tape can do this (acting a bit like a half wave plate) but they're in small strips so unless the backing plastic can be found somewhere in a large sheet form I'm not sure how good it would look. It preserves brightness shockingly well, though.

 

Edit: some of you have suggested mounting one of the panels back-to-front so they either face each other or face away from each other. This is actually a really interesting suggestion and it may be the solution for much higher brightness levels as it doesn't require the depolarisation or rotation, so I'm going to do some experiments!

Hi

 i try it with a 24 inch monitor with stock backlight, from 300 nits to 9-10 nits with tracing paper is what give me better results. also try sticky tape give a yellowish and less light than tracing paper.

Back to front panel maybe its a good idea but the only way i think its possible is using obs(streaming one screen to the other) and flip the image, having BGR instead of RGB in one panel affect the image?

Removing one polarizer its dangerous but wich will be the best to remove? second back or first front?

Are you working in a second video? a small video update will be great

@diyperks It was amazing idea and perfect video,..

But now i just create review video about DJI FPV googles on the matket is right now 4 pieces from. year 2019.

-DJI FPV googles V1

-DJI FPV googles V2

-DJI Googles 2

-DJI Googles Integra

DJI googles integra is the New ones and have 2x0.49 inch OLED displays... the screen is beautifull 

But i perosnali Like DJI Googles V2 beacause it have biger 2x2 inch screens ..but this screens are LCD TFT... 

colors on the integra google is amazing and and i want to ask you if its possible make conversion screen on DJI googles V2 like you do with monitors in your video .

if you can do this you will Be FPV KING on the whole planet Earth 🙂

many people preffer DJI google V2 because have better low latenci in ms, and better screen 144hz vs 100 hz integra, and DJI FPV google V2 have changeable antenas , you can change stock antena to third party long range antenas

I own DJI FPV google V1 and is not compatible with  new DJi air unit O3 what is definitively better than previous version air unit V1...and this is reason why many people want buy DJI Google V2  because this support new air unit O3...

and if it possible improve DJi Google V2 screen with your idea it will be amazing

here is link where is possible buy Replacement LCD for DJI FPV google V2 or V1 its looking same

1. Replacement LCD screen to buy

and here is some video from replacement screen 

some replacement video from youtube

I know its very complicatet projec it will  do many steps if its possible , like print some new parts on 3d printer or milion steps  ... , but if somebody can do this, is only @diyperks 🙂

Has anyone tried any further experiments??

I have only a couple of points to make..

1. has  anyone tried to remove the polarization coating? It seems easy enough...and could result in less light required and perhaps less distance between panels which should sharpen up the text.

2. I think the back panel should have all color turned off - the service menu should allow for this - I would think that sending  colored light to the colored panel might skew greyscale a fair bit.

I guess I have to step up and try this myself...I'm now on the lookout for identical tv's or monitors....I hope we don't let this thread die!

To me, a slower lcd panel is actually better for low frame rate movies as it makes them smoother. Especially smoother than an oled which is a bit of a herky jerky mess. So, there is more reason other than pure light output to keep this alive! 🙂

@diyperks did the cellophane idea ever pan out?

I'm considering getting some inexpensive 75Hz panels and was curious if this was baked-in as an improvement. I've also considered using privacy film as an intermediary for not trying to futz with removing the polarizing layer.

Thanks in advance!

@diyperks  any updates? I'm hoping to try my hand at something similar...and I was really hoping to hear if you tried any of the other offered efficiencies. And for me, the resulting monitor can indeed have a much lower peak light output...but certainly not zero. 

I was wondering are there polarizing films of different intensities? Perhaps ones that let a bit more light through than others?

also...watching this video, they think they're removing the polarizer...are they? I think all they did is remove the matte coating...

DIY Transparent Screen - YouTube

oh my...just as I get close to trying this out, the whole idea dies! Sheesh!!

So, if each panel has 2 polarizers at 45 degree angles to each other, then which polarizer (if any) should be removed? 

@benar23 if luminance is not important u just can do it like in the video with tracing paper i tried and got 10 nits from 300 with stock backlight and also try 180 Z flip i got 25 nits but u cant use the housing from the monitor because is desalign(and also u need to use obs to do the flip) i really liked this method in quality

Me to im waiting for an update from him to see if any idea is better than other or some issue solved

(nits mesuared using  Light Meter - Lux Meter;

First, look at a review of your monitor and see the maximum measured nits (don't look at the official specs) and then calibrate the app until it gives you the closest value. After calibration, I measured 3 different monitors and got reasonable values, not perfect, but sufficient for this.)

Someone has found a cheap way to flip the signal hardware? decimator can do this but its expensive for this and obs has to much delay

@itsme how do you measure nits? I'm planning on removing the front polarizing layer to the lower LCD and testing both of them together to see if incidental light loss is better. If it goes well, I may also remove the back polarizing layer to the front. Obviously it'll have a ceiling to its brightness, but I'd be happy to compare results.

Edit (11/11): I just disassembled the two monitors that I attempted to use and I have some feedback:

• Do not attempt to re-use the LCD backlight assembly from a monitor. Because of the lenses, it will create a moire pattern that's disorienting
• The rear polarizing layer is much easier to remove than the front polarizing layer; if I were to do it again, I wouldn't bother removing the front of one and the back of the other -- I'd just remove the rear polarizing layer.
• Having extra eDP driver boards is helpful and I think it's what I'd do in the future. I'd love to try and get a native signal splitter from a single board, but that'll require more tinkering 
• LED strip (or panel) backlight is going to be a must. I was hoping to avoid the big bulkiness both for aesthetic reasons but also because I don't yet have the tools, but I think it's unavoidable. You can still reuse lots of the items from the backlight assemblies, however -- namely one of the acrylic layers and maybe a diffusing layer

The experience has made me interested in trying to do this with higher resolution screens, because even though I didn't get this to work, I feel like I'm in striking distance. 

@0xe1 I thought the exact same thing, allows more light to come in by removing 2 layers

That sounds intriguing! Removing the rear polarization layer while keeping the front one could create an interesting visual effect, similar to the "spy" LCD. It might alter the image quality, but it’s definitely worth experimenting with to see how it turns out! urdu love quotes