Naturally Backlit Monitor

nLCD

Here is a prototype that i'm currently working with (Link):
https://www.youtube.com/watch?v=s-jYgVdAq9o

I mainly use the screen with natural light, but at night I also use incandescent light bulbs.

I don't recommend LED or fluorescent lights, because they will always flicker. There's no good LED and probably will never be. They may increase frequency, but the problem still remains. Here is a good video that will show what i'm talking about (Link): https://youtu.be/Fo_1fZfv0P8?si=NWPHI4ouhqn1FWdy

This is my solution for the problem. Feel free to comment or ask anything.

photon78s

nLCD

Do you notice improved contrast as well compared with conventional displays? I'm also using a diy prototype (super ugly but it works) using a 14 inch laptop panel and the overall screen contrast seems much better. Hard to shown on camera.

Also I still need to fix the uneven backlighting from a single incan bulb. Notice in the top right corner a part of the diffusion layer is missing and how the screen is dark in that section.

beyondthelight

photon78s

Nice to see you made it!! but in my opinion there is no need to put f.lux, just put more bulbs and dim them, did you get inspired by the open source plans from the site?

nLCD

beautiful working prototype!!, certainly natural light is the only antidote for screen strain, incandescent light sources are inherently different than led sources, incandescent backlight is the future if you want to reduce and eliminate eye strain. I see in your videos that you are in Finland or at least speak Finnish, you have some friends in the other side of the world who are also hand making them, its a lesser known small company from Mexico that just started spectrumview.com its the same principle you are using, but more developed.

nLCD

photon78s Black color seems better and everything is more lively in my opinion. The contrast seems fine with this cheap monitor. I still want to build a new one with a better panel so i can really see what these new backlights are able to do.

A laptop screen is much easier to convert for the natural light and i think i'm going to do that as well in the future.

LED-backlights are too bright for night use for me even in the lowest brightness settings. Before this prototype i have used a program called "f.lux" to adjust warmer colors to LED-display. It have helped my eyes, but it still wasn't enough.

With Windows 11 i'm always using a dark mode and high contrast mode. This automatically affects every web site that i'm visiting and i have always a black background and green text for everything.

I prefer incandescent lights because they have more rich color spectrum and my eyes like it. I have bought 100W incandescent lights with a 3.000h lifespan which is more than regular halogen bulb (2.000h). If i need more precise colors then i'm using halogen bulbs. That is why i have both light types in this prototype.

It's always nice to hear and see these DIY projects from others.

nLCD

photon78s I know the feeling. I'm trying to take a video about my screen, but the camera can't take a real looking shot. Some how camera is unable to handle all the colours and deepness in the picture.

This is just a thing which is needed to see in live conditions.

If you use two bulbs it should be easier. You can add another light spreading film layer to balance the light.

photon78s

nLCD

Thanks for the info! The laptop panel from a thinkpad t480 I'm using was already quite good resolution wise but now safer without the backlight. About the streetlight video, I posted this link before.

https://dl.acm.org/doi/abs/10.1145/2993422.2993570

It's about researchers using cameras to film the flicker of city lights to figure out energy consumption. Shows that flicker is everywhere.

nLCD

photon78s I have (24") and (1920x1080@75Hz) screen. I think i need a 4K@120Hz resolution/rate for the next one.

If we want to lower energy consumption, then i think the next step would be to manufacture transparent, naturally backlit and front reflector screens with added LED-lights and also other optional light sources.

Here are three examples:
(1.) "Sun Vision rE" with front reflector: https://youtu.be/c0TcGjzKbag?si=JfnAmT5ZhTYRcKc6
(2.) "Eazeye" with back reflector: https://youtu.be/CyREzsdg1xo?si=La5sp_eKgBzsyx7A
(3. "Transparent TV" https://youtu.be/oPOhKULOL4o?si=MLF_IFCodOwoZfBG

That incandescent bulb in slow motion was very interesting. It would be good to see a side-by-side comparison using the same camera with an incandescent light and LED.

But fortunately an incandescent light bulb needs a one second to fully turn off and where i live we use 50 Hz, so it's enough for my eyes at the moment.

I'm curious that is it possible to add another +50 Hz to incandescent bulb to make it even smoother and is it possible to do in home enviroment?

photon78s

nLCD

I tried using a battery powered flashlight (~90-100 lumens), but it was too dim but in theory could work with multiple of these. However, incandescent flicker is known to be safer than led flicker.

https://www.flickersense.org/testing-leds-and-screens#h.k0tf7fxa4n7d

I also prefer higher pixel density which I don't see in existing commerical products. My prototype is 2560x1440 at 14 inch 60Hz panel refresh rate.

photon78s

nLCD

nLCD camera can't take a real looking shot. Some how camera is unable to handle all the colours and deepness in the picture.

Depends on the camera but another issue is people will view video through regular monitors. Maybe a side by side shot with regular display if that helps.

If you have a light refracting material at a distance behind the panel like a glass bottle, this creates a fun depth effect because the the screen becomes actually a translucent window into a 3D space behind the screen rather than a flat plane of light. Not practical but I can think of art projects with this effect combined in interesting ways with what is shown digitally in the panel itself.

qb74

@nLCD @photon78s
I just want to voice my appreciation for this, great posts 👍️

madmozg

Great work! I have a few questions here to update my knowledge:

Is regular DC dimming backlight cause eye strain as well?
How your natural light backlight solution going to help in situations with dithering/pixel inversion ?

I repeat, this is just for me to understand better.

photon78s

madmozg

madmozg Is regular DC dimming backlight cause eye strain as well?

Yes because in practice one can still measure flicker (like using very sensitive photodetector) with claimed "flicker free" products and even tiny amounts of flicker can have effects (from amplitude/modulation depth and/or flicker patterns of frequencies).

madmozg How your natural light backlight solution going to help in situations with dithering/pixel inversion ?

It's not going to help in my understanding because those are determined by the monitor electronics like control board and software, gpu, etc. on the source signal side. I measured similar pixel flicker under the microscope in the prototype compared to regular setups. Their is another theory that PWM masks pixel flicker like pixel inversion so if this the case, having truly no flicker backlight might make the dithering/FRC/inversion effects worse but I am just guessing here.

In my limited testing so far, I still get some strain even while using the incandescent light. However, in sunlight, I get less strain but this is to be determined with longer use. For example, a few days ago, I read a two hundred page e-book using sunlight outdoors and did not feel any strain (using intel igpu T480, stock linux mint 21.3). Of course various other factors like fresh air leading to better blood oxygenation to eyes might be at play.

nLCD

madmozg * Natural light as backlight does not strain my eyes. The screen is bright and "flicker-free".

* Incandescent bulbs are very good as background lights and eye-strain is very minimal, because they have a very long turn-off time (1 second) and ignition is 50/60 times per second.

* About dithering and inversion i don't have enough knowledge yet.

I have lift the screen to my eye-level and now i can use the screen while standing:

photon78s

Using f.lux "reduce eyestrain" or any of the incandescent modes can reduce the blue color frequencies but software cannot add colors present in sunlight that the led backlight hardware cannot physically reproduce. Another reason why doing these projects can be worthwhile.

nLCD

photon78s Correct me if i'm wrong, but there is no white LED, only blue LED with some kind of color filters, which are supposed to make blue light to white. If i stare a blank screen with VA- or IPS-panel. I see the black is still glowing blueish.

"White light emitting diodes (wLEDs) have become, in the last decade, the most efficient device for most lighting applications. They are mainly composed of indium and gallium for the blue emitting LED, and rare-earth elements for the phosphor producing the yellow component of the white light." -Science Direct

nLCD

Here might be a solution for incandescent and halogen lights. This device can adjust output frequency in range of 0-400 Hz:

photon78s

nLCD

I think this is correct. The US National Science Foundation has this article about developing ones that r
"reduces" not masks the blue. We shall see if this actually solves the problem.

Now, U.S. National Science Foundation-funded researchers reporting in ACS Applied Materials & Interfaces have developed a prototype LED that reduces -- instead of masks -- the blue component, while making colors appear just as they do in natural sunlight.

Commercial LED bulbs use blue LEDs and yellow-emitting phosphors, which appear as a cold, bright white light similar to daylight. Continual exposure to these blue-tinted lights has been linked to cataract formation and turning them on in the evening can disrupt the production of sleep-inducing hormones, such as melatonin, triggering insomnia and fatigue.

So, Jakoah Brgoch and Shruti Hariyani at the University of Houston wanted to develop a phosphor that, when used in a violet LED device, would result in a warm white light while avoiding the problematic wavelength range.

TaraSnowdrop

nLCD yes, most leds now are blue with a coating to change the colour and give the appearance of white light

beyondthelight

TaraSnowdrop

TaraSnowdrop yes, most leds now are blue with a coating to change the colour and give the appearance of white light

there was never a white led that was not blue or ultraviolet in its source