(Idea) Eliminating Light Leakage at the diffuser in Scanning/strobing Backlight with QD

[blurfreeCRTGimp]

I don't know if any of this will be clear, make sense, or if it would even work. LOL chief let me know.

Had this thought this morning while I was getting up. The issue of light leakage, and light control seems to be a big thing limiting scanning and strobing LCD, not for our lack of trying.

FALD works great, but has the expense associated with adding all the zones. Dual cell is awesome, but yet more expensive, and with artifacts, all to get contrast.

Scanning would work great with IPS, but is untenable because of the light bleed and leakage between the illuminated and non illuminated sections.

As we all know, there is still light bleed even between tiny dimming zones in the backlight due to this same issue.

This got me thinking. Could a Quantum Dot be fabricated that tunes light into infrared, making it invisible to our eyes?

The reason I ask is that If this could be done, IR quantum dot patterns could be printed onto the diffuser layer of the LCD acting as a kind of picture frame around the dimming zones in the areas where there is too much light leakage. Rather than controlling the leak, we just get the light out the spectrum visible to our eyes.

I suppose you could reverse this and use IR LED in the Backlight and then just print RGB Quantum Dots (for the pure white light) onto the diffuser layer to accomplish it too.

Basically, rather than try and stop the light, just make it so we cant see it.

[Futuretech]

Earlier in the decade before it started sometime when the 1080P craze was in full swing the whole 16:10 1200P vs 16:9 1080P and even the 1152P 16:9 from Samsung's 2048x1152. There was a company that manufactured a filter called A-TW Polarizer filter or the companies made their own I'm not entirely sure I do recall reading there was a company that was the provider of said filters or maybe the companies themselves made and never budgeted it out to the lower end monitors. In essence they couldn't or didn't want it to be cheaper or never cared to make it cheaper.

https://www.monitortests.com/a-tw-polarizer.html

AT-W = Advanced True-Wide polarizer filter.

https://hardforum.com/threads/why-manuf ... m.1639972/

https://hardforum.com/threads/nec-2490w ... 29/page-15

https://nec2490.blogspot.com/

This filter is something interesting that I'm surprised has not been resurfaced or improved from. Kinda like the mechanical keyboard crazy that began in late-2010/2011 with Geekhack and OCN particularly Manyak who was a big baller at the time doing reviews.

This filter might have had use in the future if improved I'm sure the negatives of it like some stated would be able to be overcome.

This is one possible simple cheaper solution unfortunately it seems they just stopped manufacturing them.

[MCLV]

I'm not sure if I got what you really think this would achieve but instead of converting to visible light to IR, you can simply use a black pigment to stop it. It would work the same, visible light in, no visible light out.

Converting IR to visible light is much harder because you need to capture 2 or more IR photons to convert them to 1 photon of visible light. This is due to conservation of energy and the fact that photons with shorter wavelength have higher energy. This is the reason why blue light is converted to other colors by quantum dots in todays display technologies.

[blurfreeCRTGimp]

"I'm not sure if I got what you really think this would achieve but instead of converting to visible light to IR, you can simply use a black pigment to stop it. It would work the same, visible light in, no visible light out."

@ MCLV Sorry if i wasn't clear, knew I would be unclear lol ; ) . I will try to explain better.

If you take the light from the Backlight, and use an IR Quantum Dot for conversion of visible light into the non visible IR part of the spectrum placed on the diffuser layer nearest the backlight, you would get rid of the annoying glow left over from around FALD backlight zones, and also the light that leaks between the segments of a segmented scanning backlight, when viewed directly on angle, but also off angle without actual brightness loss where you don't want it.

The crucial parts that I guess I missed.

It would do this WITHOUT more complexity in the electronics, (would help minimize bloom on sets with fewer zones) and IMPORTANTLY WITHOUT adversely affecting the output of the light that you DO want to get through to the display. The IR light would still be picked up in the color conversion QD layer, but as you said, "

Converting IR to visible light is much harder because you need to capture 2 or more IR photons to convert them to 1 photon of visible light."

so You get less bloom, and the light that does get through still contributes to color.

With this idea you are "blocking" the light without actually blocking any of it. You have IR QD on the diffuser layer, and the standard QD for the color conversion layer.

does that make better sense?

The afterglow and leaked light is really hard to deal with on your average diffuser (because they work so well) but this way it would be effectively "blocked" to your eyes, because you can't see Infrared, but you don't actually lose any of the light you do want. You didn't really block, you just shifted the light you don't want to see out of visibility in sections where you determine as the manufacturer it needs to be blocked.

A black pigment would indeed work to block light, but it also very negatively effects the light output and efficiency of the light that you actually do want to see on the screen.

Its why manufacturers of LCDs haven't added black pigment like that since the very early days of LCD.

Pigment did improve contrast a lot, but it also nuked brightness and color too. This would accomplish similar without the drawbacks, in theory.

With IR tuned Quantum Dots placed like a frame on the diffuser layer around where you know light leakage will occur near the individual LED zones you effectively "block" the light, but don't lose it.

[MCLV]

Could you maybe draw some sketch to demonstrate the idea?

With IR tuned Quantum Dots placed like a frame on the diffuser layer around where you know light leakage will occur near the individual LED zones you effectively "block" the light, but don't lose it.

Blocking the light is the same as losing it. As I mentioned, this conversion to IR does the exactly same thing as black pigment does for human eye.

Conversion of IR to visible light would required different quantum dots than ones that are used to convert blue light to other colors. Additionally, as far as I know, this up conversion of wavelength was achieved but the efficiency of this process is low. So the IR light would be lost in practice as it would be with the black pigment.

It's still not clear to me what kind of magic should happen with IR light anyway. Because if you place this layer between backlight and the diffuser, then the diffuser will obviously still diffuse the light. And if you place it between diffuser and LCD panel, then the light was already diffused so you gain nothing.

And I'm sure that you can make weaker diffuser or separate dimming zones with some physical barriers to decrease crosstalk but then you very likely run into issues with homogeneity of backlight. I believe this is the reason diffusers are still relatively strong because you would have strong dirty screen effect otherwise.

[blurfreeCRTGimp]

"Blocking the light is the same as losing it." "So the IR light would be lost in practice as it would be with the black pigment." "does the exactly same thing as black pigment does for human eye."

NO, because the light is still there. and can be upconverted with this approach, unlike with black pigment, even if the process is inefficient.

If you used black pigment, you would lose ALL of the light, because there is no recovery of any photons once they have been blocked.

If you covered the screen in a layer of black pigment, or you used more polarizers, you would lose both the light you want to block, as well as the light that you do not want to block, because its a black pigment.

If you used IR Quantum dots in the same way you would use black pigment to block the backlight, you lose the light where you want it lost, and in the areas where you do not want light lost, you LOSE LESS LIGHT because the photon up conversion takes place, even if it takes 2 IR photons to make only one visible photon again.

"Conversion of IR to visible light would required different quantum dots than ones that are used to convert blue light to other colors."

yes.

In effect, this would do what black pigment used to do, but not with the drawbacks that black pigment used to cause. So, you could block light, but maybe not get black crush, finer tuned control around the edges of dimming zones, being able to lose SOME but not all the light.