Moddable LED Backlight [for brighter strobing]

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lol37
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Moddable LED Backlight [for brighter strobing]

Post by lol37 » 24 Dec 2013, 15:34

Hello,
I wonder if future ( or current ) monitors could be easily modded in a such way to implement more powerful and customizable LED ribbon ( like as Mark Rejhon said, enought wattage to put 40 000 lm/m² in a very short time ) for the upcoming G-SYNC strobing upgrade or other lightboost similar feature
Thanks for upcomings reply.

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Chief Blur Buster
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Re: Moddable LED Backlight

Post by Chief Blur Buster » 24 Dec 2013, 15:48

Very good question for Blur Busters knowledge of strobe backlights;
Let me address this in two parts:


(1) The backlight versus the edgelight issue.

After my Arduino scanning backlight experiments, I found out that edgelights were vastly easier and more efficient than backlights. Backlights are extremely difficult to make uniform, without lens or parabolic mirrors.

Image
(From a section in my "Creating Strobe Backlight" document)

Then I consequently discovered LightBoost, an off-the-market solution that was much more easily hacked/modded (there are now 5 different ways to enable LightBoost!). The rest was history. Although a lot of us call it "backlight strobing", it's really become "edgelight strobing" nowadays, because of the way most LCD's are manufactured.


(2) Making strobing brighter

With edgelights, you can use lower lumens to get a brighter illumination.

Moderate voltage boosts can be safe: The easiest way is to simply us voltage boost. An example is CREE's Pulsed Over-Current Driving of XLamp LEDs. You can typically briefly use a higher voltage pulse to make LED's about 3x brighter, provided the illumination is brief. That's very convenient for strobe backlights/edgelights, since each flash is brief, anyway.

Modifying LightBoost for brighter flashes: One Blur Busters reader actually modified a BENQ XL2411T for a brighter LightBoost=10% by adjusting a voltage-boost component -- see Modifying a LightBoost Monitor for brighter strobes (part of the same "Creating A Strobe Backlight" document).

There are brighter options now on market: Right now, the brightest strobe backlight out-of-the-box is Eizo Turbo240, found in the Eizo FG2421. It manages to achieve 250cd/m2 average during strobe mode, which is almost too bright for my eyes. It is probably already using a boost voltage (similiar to the above).

Edgelights can be modded with bigger LEDs: Another possibility for a monitor hacker is to remove a monitors' existing edgelight, and add a prism/mirror that focuses a powerful light source (bigger heatsinked LED's in a line) directly into the opening of the original edgelight, at the edge of an LCD. This would enable exactly what you are describing.

Shorter strobes requires brighter strobes to maintain average brightness. This is a big challenge of strobe backlights. CRT phosphor shine insanely bright (thousands of cd/m2) briefly to compensate for the short duration of their flicker. Eventually I'd like to see sub-millisecond-league strobing (e.g. 0.5ms strobe edgelight with capability for average 300cd/m2), since I can easily tell apart 1.4ms from 2.4ms for LightBoost=10% versus LightBoost=100%. Mathematically 1 millisecond of strobe duration equals 1 pixel of extra motion blurring during 1000 pixels/second motion (assuming framerate=stroberate, and for simple squarewave ON-OFF strobe). Video game motion are often very high framerate, very clear graphics, and often faster than 1000 pixels/second, and fast GPU's allow framerate=stroberate. Here, the 1ms differences in strobe-flash-durations becomes easy to see in tests such as TestUFO Panning Map Test especially at 1440 pixels/second or 1920 pixels/second.


P.S. Though it belongs here too, I've added a redirect to Area51, since this is in the "display hacking" universe too!
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

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Ahigh
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Re: Moddable LED Backlight [for brighter strobing]

Post by Ahigh » 25 Dec 2013, 00:17

One approach to reduce blur while still keeping a bright screen is to have three states for driving the LED. Off, normal, and overdrive. The overdrive state should be as short as possible, and the normal state could be selectively bright to reduce flicker by keeping the backlight lit at a dimmer (independently selectable level of brightness).

I've not read any research papers about having a max bright fast strobe and another peroid of time of dimmer lit pixels, but for a CRT, even though the brightness falls very fast, it can take a VERY long time for the brightness to fully fade away on some displays (phosphor persistence). Simulating this with a 0.5ms or shorter super bright mode followed by a significantly less bright phase following that for a few more milliseconds (10% to 90% of the remaining frame time maybe also selectable) would possibly yield some desirable characteristics -- increased brightness for static images, but still allowing details to be made out for fast-moving objects.

SS4
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Re: Moddable LED Backlight [for brighter strobing]

Post by SS4 » 25 Dec 2013, 19:15

This conversation made me thought about something . . . Will blurbusters eventually sell their own modded monitor in a similar fashion to what Overlord is doing but with a focus on lightboost with brighter LED, increased voltage, lightboost G-Sync and the likes ? Or maybe some hardware for DIY (or at least a list of parts kinda like the 120+ HZ monitor list)

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Re: Moddable LED Backlight [for brighter strobing]

Post by Chief Blur Buster » 25 Dec 2013, 19:19

SS4 wrote:This conversation made me thought about something . . . Will blurbusters eventually sell their own modded monitor in a similar fashion to what Overlord is doing but with a focus on lightboost with brighter LED, increased voltage, lightboost G-Sync and the likes ? Or maybe some hardware for DIY (or at least a list of parts kinda like the 120+ HZ monitor list)
I am, actually, rather, pushing very hard for strobe backlights:
-- Some display manufacturers have finally noticed. LightBoost becoming a popular niche among high-end gamers -- and the publicly available information I've provided (e.g. LightBoost HOWTO, as well Electronics Hacking: Creating a Strobe Backlight).
-- ToastyX created Strobelight, thanks to my prodding of him to create the software,
-- I am one of the first people outside of BENQ to have an XL2720Z (beta unit) with the BENQ Blur Reduction feature, and I've given them feedback that is being incorporated in production firmware update.
-- At the last minute NVIDIA decided to have Blur Busters do the GSYNC preview. In the process of that, I gave NVIDIA a large beta test report, with valuable feedback to NVIDIA.
-- There's more that I currently can't say at the moment.

Blur Busters isn't going into the business of making computer monitors -- But rather providing my services to help make strobe backlights become available (at all) to begin with, and when they do become available -- how to improve the quality of them.

There is an external display testing device that Blur Busters will be selling -- keep tuned. Meanwhile: I'm looking for someone who has small-run manufacturing experience for a computer accessory style item -- or someone with Windows device driver writing experience -- please send me a PM privately.
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

SS4
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Re: Moddable LED Backlight [for brighter strobing]

Post by SS4 » 25 Dec 2013, 21:19

Interesting, i kinda figure you werent gonna retail but i wanted to get an idea of which direction you wanted to take your business (i assume its safe to call it a business rather than a venture at this point?)
Judging from your post its a little like what i imagined you doing, but its nice to get a better insight on this.

Now regarding strobe light, you think in the foreseeable future there will be a way to use lightboost while retaining a great color accuracy and decent brightness ?

Atm im a bit more interested in G sync i must admit because lightboost requires 120+ FPS at all time to perform best and its rather hard in some scenario, but hopefully those two gets combine soon.

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Chief Blur Buster
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Re: Moddable LED Backlight [for brighter strobing]

Post by Chief Blur Buster » 25 Dec 2013, 21:40

SS4 wrote:Interesting, i kinda figure you werent gonna retail but i wanted to get an idea of which direction you wanted to take your business (i assume its safe to call it a business rather than a venture at this point?)
As of winter 2013-2104, it is now. Blur Busters, which has been formerly strictly a 100% hobby that's slowly becoming a second career (second job), so I've now made it a business today. For a long time, it was 100% hobby and 100% unfunded, but eventually that had to change. I now do small contracts for companies -- And there's text-only Amazon ads throughout Blur Busters (e.g. support Blur Busters by shopping via this Amazon Link). However, at the end of the day, it is still essentially a hobby of love at the moment as the hours I put into the Blur Busters sites average below minimum wage -- i.e. Nothing compared to my main job! That may eventually change in the future, once I begin selling a monitor testing product which I've been developing (slowly).

Back on topic:
SS4 wrote:Now regarding strobe light, you think in the foreseeable future there will be a way to use lightboost while retaining a great color accuracy and decent brightness ?
I already have it sitting on my desk: EIZO FG2421 alongside the GSYNC monitor.
(5000:1 contrast ratio, bright, contrasty). I'm planning to publish a review on this monitor too, as well. It's ideal for users who prefer strobing, and can live with the VA panel quirks.

Also, better color LightBoost exists in the VG278H, which has double contrast ratio and no crimson tint, unlike the ASUS VG248QE. That said, there is no fundamental limitation to improving color quality in strobe mode.
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

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Ahigh
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Re: Moddable LED Backlight [for brighter strobing]

Post by Ahigh » 25 Dec 2013, 22:57

Chief Blur Buster wrote:Also, better color LightBoost exists in the VG278H, which has double contrast ratio and no crimson tint, unlike the ASUS VG248QE. That said, there is no fundamental limitation to improving color quality in strobe mode.
I have the VG278HE instead of the VG248QE myself. I may have to wait to get the G-Sync setup and/or a VG248QE, but I'm okay with just constant framerate strobe at 60 Hz for the time being with what I'm doing that is possible on other displays with backlight strobe. I do expect to have a faster setup after that, and a G-Sync setup after that. But strobe and good color is more important to me that G-Sync.

That being said, I won't be 100% happy until I have no view-angle color artifacts, strobe backlight with plenty of average luminance, 4k, and up to 240hz Gsync'd in any size display that I feel like using, maybe even with passive 3d as an option on top of all of that.

I think we're still more than a year away from all of that being available.

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Re: Moddable LED Backlight [for brighter strobing]

Post by Chief Blur Buster » 26 Dec 2013, 08:15

Ahigh wrote:I have the VG278HE instead of the VG248QE myself.
The VG278H is reportedly better than the VG278HE when it comes to LightBoost. There's less checkerboard/inversion artifacts (www.testufo.com/inversion) on the VG278H than the VG278HE, and it's much, much less on the VG248QE. However, contrast ratios in LightBoost is highest on the VG278H (when OSD Contrast=90%, no white clipping, no black clipping, unlike VG278HE and VG248QE).
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

SS4
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Re: Moddable LED Backlight [for brighter strobing]

Post by SS4 » 26 Dec 2013, 14:18

i think thats what i hate about today's current technology . . . theres no perfect or better solution, they all have their drawbacks and also different benefits as well.
Like i said before it comes down to picking your poison (contrast, blur, color, response etc . . .).
i do think that the way things are going we might see something that trumps all we have now in all aspect or close. (Well i certainly hope so at the very least):P

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