DIY "infinity contrast" TV – with 100% recycled parts [video]
30 comments
·March 4, 2025withinrafael
Very cool and a great speaker. Forgive my naivete but would enclosing the back with a short-throw projector reintroduce the LCD light bleed he fought hard to eliminate? I wonder how you would address that. I suspect painting the interior Ventablack wouldn't be enough.
gibibit
A bit clickbait calling it "infinity contrast" even if it's higher contrast than an LCD, is it still a finite contrast. Probably not higher contrast than modern OLED TVs, but a clever hack with stuff at hand. Just not up to the hype of infinite.
Kirby64
The author is using a DLP projector to backlight the LCD. When the projector is displaying black it effectively is infinite contrast. The light is reflected away and never reaches the LCD to backlight it.
smusamashah
Black color coming from projector isn't full black either https://www.projectorreviews.com/articles-guides/projector-b...
wdfx
He also did not do (or at least did not mention) anything about the reflected/diffused and ambient light behind and around the TV screen, which would negatively impact contrast.
mlyle
No. It's not literally infinite contrast.
On the other hand, there's very little light spill from DLP--- and what little there is, is attenuated by a really big factor by the LCD.
I'd guess the limiting factor is light scattered elsewhere in the room and by the front surface of the display.
mbreese
True, but for this purpose, it's "blacker" than a typical LED backlit TV. For a Youtube / DIY project ... I think the description is fine.
gibibit
Good point, I hadn't even thought of this.
SirMaster
That's not true at all. Black on a projector is still projected light, especially with a DLP which have the worst contrast ratios of the 3 projector types (DLP, LCD, LCoS).
What he is making here is a dual panel display. There are actually some LCD monitors that use this concept of 2 separate panel layers each providing their normal contrast resulting in a multiplicative effect.
For the video posted here, the DLP is probably at best 1000:1 and the cheap old LCD is also maybe about 1000:1, so you get about 1 million:1 which is a lot, but not technically infinite like self-emissive display that can turn off the pixels completely for sections of the picture like OLED and microLED.
tshaddox
> Black on a projector is still projected light, especially with a DLP which have the worst contrast ratios of the 3 projector types (DLP, LCD, LCoS).
If DLP has worst contrast than LCD, then why would this project be even remotely successful? Wouldn't the LCD layer in the stock LCD TV would have already been more effectively blocking the light from the stock backlight?
Dylan16807
What makes self-emissive "technically infinite" but not DLP?
I would say the weak point of DLP is the screen material needing to be light-friendly, but that's on a sliding scale with the emissive display, not a hard line difference. Both of them preserve black levels when turning on, unlike traditional LCD, but also it isn't true black for either of them.
gibibit
Ignoring the fact that the projector doesn't get to true black (noted by smusamashah), and supposing there's no diffusion that spreads the light of a pixel out to surrounding areas of the display panel, it would be possible to say that the display has infinite contrast, I suppose that is true.
Contrast is important, but alone it is useless. You could have a display with only two levels: black and white, and if the black is perfectly black, then it's infinite contrast (any level of white, no matter how dim, is infinitely brighter than total black), but 1-bit color would be useless in reality for home theater.
To make infinite contrast useful, it's necessary to have HDR as well to take advantage of having very dark and very bright areas both able to be represented with detail. Plus having sufficiently bright maximum brightness so that the brightest highlights can really shine.
deepsun
Just to note that absolute black is not achievable. The best coatings in labs reach 99.99% but it's never 100%.
nickthegreek
Not sure I would call that clickbait when the Creator put that phrase in quotes in the original video title.
smusamashah
FIY, current substitute title (using DeArrow chrome extension) is "DIY Rear-Projection TV - Recycling Broken TV And A Projector"
smusamashah
When I read infinity contrast, and knowing how great DIY perks is, I assumed it to be something like this https://youtu.be/JoLEIiza9Bc?t=335 but couldn't wrap my head around the idea on a TV.
numpad0
the joke is that contrast is a ratio, and any number over zero* equals +inf. I've seen similar lines used in OLED advertisements during 2010s, despite many OLED having non-zero minimum intensity. It's a reference to those.
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firefoxd
I'm glad he is back to making approachable projects. It was a boon for me during the pandemic. I particularly love the fake windows to light my closet that looks like daylight.
PhunkyPhil
Is that one really doable?
It's one of the ones that's been at the top of my list, but my lack of engineering/tinkering experience has made me a bit apprehensive. Is it result really worth the effort?
uSoldering
I think it's odd to make a whole video about a DIY rear-projection television without using the phrase 'rear-projection television'. It's novel to bounce it off the ceiling, and it repurposes e-waste so it's a great project.
tobr
He does mention rear-projection TVs.
uSoldering
I guess I missed it and was hoping for a deeper dive.
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anadem
Nice, but he totally hides the lining-up of the rear projector image with the main screen's image, which I imagine is a painful process.
badmintonbaseba
I would be more interested in matching up timing/latency, especially with the OBS processing in the middle.
laweijfmvo
he talks about that extensively and goes over the software fix(es)
KeplerBoy
meh, he doesn't really address the issue. He just mentions using OBS to threshold the image and dilate the resulting regions.
That raises a lot of other questions: He obviously feeds two different videos to the displays. How is this done? Does it add latency, does it work with, let's say, Netflix DRM? Are the two videos even in sync or is the obs post processed feed always N frames behind (think of the transition between barely lit and bright scenes)?
ThrowawayTestr
The results he's able to achieve with this are very impressive. I wonder if consumers would accept a TV that isn't paper thin if it had OLED performance at LCD prices.
Very cool, and great video.
It seems that projector tech (like laser printer tech, and flatbed scanner tech) has been pretty stagnant, the last few years.
Every now and then, I look at the latest projectors, to see if there's any justification for me to replace my old (10 years or so) LED projector, and I have not seen anything that has made me want to.