How Digital Light Processing (DLP) works

Digital Light Processing projectors use a chip that is covered with tiny mirrors that tilt back and forth. When the mirror is tilted one way, it reflects light out through the front of the projector, creating a bright pixel. When the mirror is tilted the other way, the pixel is dark. In this video, I explain how DLP works and show a macro-scale model.
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[@_Junkers]

People like you are what make the internet great

[@bryanp4827]

Correct!👍

[@pendalink]

100%

[@sushibobagenius9813]

Yessss!

[@CookingWithCows]

Am I the only one thinking "holy shit we are able to create and assemble mechanically moving objects so small that you need an SEM to look at them" ? That is amazing. Sure nobody bats an eye anymore at 22nm processors but.. We're talking actually mechanically moving things

[@Mythricia1988]

I agree. It is pretty amazing. What's even more amazing is that we use devices with this kind of complexity every day, and don't bat an eye. Or the fact that you can buy a chip made using this super complex and mega-expensive-to-develop manufacturing technology for literally .1$ a pop. It won't be a very interesting IC chip, but, doesn't mean it's not amazing that it exists and is sold for basically nothing!

[@batcathatsatchat]

Not only do you need powerful microscopes to look at some of these mechanical system, but we have even brought down mechanical systems to the point where their vibrational modes need to be treated quantum mechanically. See eg k-lab.epfl.ch/page-102900-en.html

[@HarishSasikumar]

MEMS (Micro Electromechanical Systems) en.wikipedia.org/wiki/Microelectromechanical_systems NEMS (Nano Electromechanical Systems) en.wikipedia.org/wiki/Nanoelectromechanical_systems

[@pirobot668beta]

***** There is an effort underway to make a Babbage engine about 1 cm on a side. Why? Parts that tiny can run at millions of operations a second. A Babbage machine can do a lot in a single clock cycle.

[@whadrillival]

+Cooking With Cows I'm totally amazed too. I was hoping he would go into the other method of getting all the colours. Same principlal with the mirrors but there are 3 light sources pointing from different angles. So the mirrors have to move in more directions, even more tiny moving parts.

[@chiraldude]

Adding a few more things, I spent several months doing competitive analysis of DLP chips when I worked at Hewlett Packard. The torsion hinge is not silicon but a titanium/aluminum alloy. Lots of interesting material properties of Ti/Al I won't get into here. The most important thing missing from the narrative is that this device was the first truly micro electro-mechanical device. I say that because it is not just electrostatics that are responsible for the mirror motion. If you look carefully at the SEM images, you will see that, under the mirrors, there 4 little tabs attached to the posts. These are actually tiny springs. When a mirror is flipped to one side, the electrical force holds it down. What is really interesting here is that when it is time to flip the mirror, a short voltage spike is applied to the "down" side. This pulls the mirror down on these little springs then lets it go. The result is a very fast flip to the other side where there is a voltage applied to hold it there until it is time to flip it the other way. If you are wondering why it is this way, think about the inverse square law. On the down side, the mirror is about 100 nanometers from the electrode. On the up side, the mirror is a couple of microns from the electrode. The force on the down side is hundreds of times that of the up side. It will flip by pulling from the up side but it will be way too slow for a video projector. Pull down really hard for a microsecond then let go and the mirror flips really fast! Pretty cool technology from TI. Note that Hewlett Packard didn't ever produce a projection chip. They spent a lots of millions and couldn't come up with something that could do better that the DLP chip. But, that's another story...

[@raykent3211]

that's fascinating! the stronger force available is in the wrong direction, so use that to pull it against a spring and then let go... clever. I just assumed that they used the piezo effect to move the mirrors. Any short explanation as to prefering electrostatic?

[@reddaB]

cool

[@connordow7366]

wow how can you make something so small and perfect?. if we can make tech that small then whats keeping us from making nanobots?

[@brainfornothing]

Very interesting info. Thanks !

[@frankgutierrez6016]

I worked on DMD for about 12 years.

[@TheBackyardScientist]

If you ever come across a 3 channel projector, they have a really neat prism inside for splitting and recombining combining the light.

[@spectralcodec]

I recenty bought an old 3 chip DLP projector off of ebay just so I could take it apart. Fascinating stuff inside this thing. Might make a video!

[@ARV1999]

I work on cinema projectors for a living. Those 3 DMD chip light engines are super fascinating and make up the majority of modern day cinema projectors. Single DMD chips are cool to with the color wheel they instead of the prisms.

[@Demossle]

Just so you know i was lurking through internet at 3:00 am in the morning, found this video and decided to watch it instead of sleeping ! nice video and keep them coming !

[@RimstarOrg]

Interesting video, Ben. It would be cool to see your macro-DLP in action. It'd also be cool to see the area in the projector that the mirrors reflect light to when not sending it to the lens - a negative I guess.

[@AppliedScience]

I like the idea of taking the "negative" image and displaying it on a screen.

[@hunakosdem]

You nailed it nicely! Thumbs up from a projector sales guy of 15 years ago!

[@queuerious]

As ever Ben, you offer a clear and accessible study of things. Many thanks for sharing your passion for investigating and questioning how things work!

[@TheMichaelGrace]

Interesting?! That was mind blowing! I've always wondered how those work.

[@lislehill3198]

Same here.

[@RealationGames]

Whoa, this was way more amazing than I thought. Thank you so much for detailed and well presented video. Seeing the actual physical item is so much amazing than an animation. I just cannot imagine how much work has been put into the manufacturing process of this. The engineers that started this idea must've been extremely ambiguous to make this concept a reality. I can hardly even believe it.

[@frankiemacaulay9417]

fantastically throughout and well explained; loved the visual aids and macro model!

[@crytp0crux]

This is a necessary video because other videos tend to emphasize CGI and theory. However, this is one of those technological subjects where the old fashioned approach works best. Great video and thanks for your hard work.

[@yivo2824]

Thank you, very clear and useful!

[@dhariri]

This was the best video on DLP projector technology I've seen. I love your channel. You could have made a simple color wheel to explain the secret sauce: the timing between the DMD and the wheel, but even without that, this video was excellent. Thanks!

[@nunyabusiness7630]

Thank you for the extremely well thought out presentation concerning the T.I. DSL properties and complete explanation of that proprietary system. I have a pico-projector that implements the DSL and I have always wondered why I would catch a glimpse of the RGB in their singular state when walking by the projector or moving my head/eyes just right. That is one hell of a system and can only imagine how smart the individual is that was able to put it all together and have it work so well.....thanks again!

[@pzencovich]

Thank you for your explanation, how fascinating this technology is!

[@Flightstar]

What's also amazing is the computing and switching power to control, organize and synchronize all this stuff to make it work.

[@DanielSoll]

What a piece of art and technology! Thanks for bringing this so elegantly to our attention!!

[@donovanpl]

Very clear and concise explanation of DLP technology.

[@danwchan]

I'd just like to say that I have been watching your videos for about a year or so now and they are amazing little lessons into your line of work and expertise. I believe the quality of the "lessons" have improved greatly and I am eager to see how this evolves in the future.

[@AppliedScience]

Thanks! I really appreciate your comment. Practice certainly makes it easier for me to make better videos. I've deliberated whether adding higher production value items (intro/outro, clickable links, animations, voice-overs, better shot setup, etc) would be worthwhile. I think that many folks watch my content because the videos are clear, but do not have any high production value features. They are also free of BS, rambling, paid placement, etc. On the other hand, I do wish that I could show certain concepts with animations that are more illustrative than my drawings. Let me know what your thoughts are.

[@danwchan]

Applied Science I am part of the audience that appreciates the clarity, lack of paid placement and lack of rambling (although I think rambling can build a type of ethos similar to Q&A at the cost of clarity). I would not trade any of these "virtues" for animations (your paper ones are pretty good). I think links improve the quality of the lesson and increase chances of people watching other videos of yours and give us an idea of the sources you use. I think you already have great shot setup, voice-over and outro. I think the fact that you respond to a high number of comments is also very admirable and enhances your educational value. This channel is a great example for KZbin education. I too am interested in the future of education and will certainly look to your channel when I finish my current schooling (PhD microbiology... I love the SEM pictures you take. I'm currently using one for my research and it is how I found your channel in the first place :D) as an example of how I might set up my own KZbin content. Thanks again!

[@pinkdispatcher]

Cool, thanks. I knew most of the theory, but what your videos add is always the hands-on part, actually seeing the real stuff. The missing link between theory and practice.

[@fjs1111]

Very ingenious demonstration model.

[@RllXeron]

I love this micro suspension! Great episode as always!

[@ChrisB257]

Fascinating stuff Ben - thank you.

[@AmyAndrewAdventures]

I am so glad I found your channel. Great stuff!!!

[@themrworf1701]

Wow!! I took apart one of DLP-s and I found this chip, and I didn't know how this thing works without polarisation. I thought that is a normal LCD chip with mirror behind. Thank you very much for this insight! I can't believe that this projector is actually mechanical! Good work Ben, I'm looking forward to more awesome videos! Take care! :)

[@zehawn]

Excellent, makes this very easy to understand - thank you.

[@Femtophysiker]

Excellent illustration!

[@DimaDesu]

Awesom explanation. Thanks for your time and efford!

[@ItistDe]

Thanks for sharing. The explantion is excellent as allways.

[@jjoster]

You never cease to amaze. Thank you!

[@bhaskarjyotidutta3253]

Very nice and clear video. Thanks for uploading.

[@frab88]

Thank you for this amazing demo

[@HunainAlwaysRight]

great video with outstanding explanation

[@databits]

Well done! Truly enjoyed this video!

[@PacoOtis]

Wow! Well done! Thanks for the video. Very clever science taking place.

[@AtomkeySinclair]

Excellent presentation.. thanks for the time.

[@jeremyrebelka]

Its one of the best channels on YT Man ! Tons of knowledge for free and a good quality one - in depth and interesting. One of the rare internet treasures - I think I will back it up form my children.

[@NicChristie]

great video - very informative. well spoken.

[@lecturesdentist]

ONE OF THE BEST VIDEOS ABOUT ( DLP) SEE

[@brainfornothing]

Very impressive. Thanks for sharing !

[@donovanpl]

Very good explanation of DLP. Always did wonder, nut never looked it up. Great videos. Keep up the good work.

[@racheljema4459]

This was so helpful!! Thank you and it was truly fascinating.

[@SKINFOTAINZ]

Brilliantly explained..thanks and keep it up😀👍

[@CADDIA]

i never seen exploration like this thank you sir

[@benner2000]

Definitely an interesting video as I begin to research and muck about with DLP 3D printing.

[@diamony123]

Thank you...great description

[@reddaB]

I learnt loads from this. Great presentation , thanks!

[@hay_williamwong_sun7501]

This is a very useful intro to DMD / DLP, many thanks!

[@juliocesarcastilloramirez8027]

Great tutorial !!. Congrats !! I needed to understand DLP technology in an easy way. This video worked for me!. Thanks a lot !!

[@mohamedqasem]

Fantastic explanation! Thanks

[@tiitsaul9036]

dude! absolutely love your channel. thank you so much for sharing

[@heroslippy6666]

As a kid we got a tour of a movie theater. They said that there are thousands of mirrors. I thought that they meant they were layered on top of each other. This is cool to see it under microscope, it makes way more since now.

[@4.0.4]

I always wondered what kind of "pixel" projectors used! But when I see the electron microscope image, now I wonder how on earth that can be manufactured. such tiny machinery...

[@samspencley7180]

Very well explained i have just purchased a DLP HD projector and am amazed that one bulb can create such an amazing picture and wanted to know how and now I do thanks grate video.

[@dsedswe]

really liked your video buddy no skipping or anything :) watched the whole thing

[@hawaiidispenser]

What a clear and informative video. You are awesome!

[@cup_and_cone]

Thanks for showing the DLP chip under the SEM. Now I know why early DLPs were prone to pixel failures.

[@NautilusCrypto]

I study Micro & Nano Systems Engineering, and this video was really helpful as an example. Thanks for the effort! It was amazing.

[@davidkempton2894]

That was really interesting. I have always wondered how these things work. Thanks!

[@NickMoore]

Very cool, I never thought about the binary nature of DLP's and how to get variable brightness from them, thank's for the info. It's funny you put this out today, I just mentioned the rainbow effect you get from DLP like illumination in LED flat bed scanners in my last video but I filmed it months ago.

[@bhandarisd]

Superb and excellent way to make people like me understand about the mechanisms behind DLP projection. Hats off to you for the hard work done by u to build this working mirror mechanism it’s amazing … Thanks for sharing this complex knowledge behind DLP Chip …👏

[@davidbrewer8309]

Great informational video. Loved it

[@mikeissweet]

Great video Ben. I see the SEM is working nicely.

[@mikeissweet]

Btw, Mike from mikeselectricstuff is them man. You two are star content producers. Very underrated.

[@thefirstspartan1]

this video is very well made, thank you!

[@bloedekuh]

This is so much better than those animated videos trying to explain the same thing, thanks a lot!

[@verydeaf2382]

finish this and play tetris on the wall.

[@inkspecialist]

Amazing video. Thanks for helping me understand this technology!

[@shariqabideen]

Wow! Thanks so much for your efforts.

[@jondoe-zq7mv]

Great explanation, and great video

[@diablo6250]

Thank you so much my kind sir. May god bless you for your efforts

[@snaprollinpitts]

very cool, thanks for the look in to this technology

[@bakupcpu]

Now this is what I love to hear :) Thanks for the info! Now I know what to look for my next projector :) Cheers!

[@2tommyrad]

just replaced the DLP chip in my Mitsubishi. Super interesting to see in 'innards'. Off to see how they manufacture it now. Amazing to be able to work in such small detail.

[@CrystalHammond]

LOVE your videos! I work at the US Patent & Trademark Office in Circuits and it's cool to see everything in person!

[@p.s.design4338]

that's really great explanation.

[@kumirei8715]

That is so much more complicated than I had expected

[@MrNBit]

Thank you very much that was extremely interesting and has given me great insight into DLP technology

[@LMacNeill]

The first HDTV I ever owned was a Samsung DLP set... It was one of the earliest DLP TV sets, and it suffered from major design-flaws in the "light-tunnel" and the color wheel. The "light-tunnel" was, quite literally, a tunnel lined with mirrors that was supposed to channel light straight into the DLP chip. Stupidly, they designed it such that every *other* mirror in the tunnel was held in place with glue, and the ones that weren't held in place with glue were held in place by friction from their neighboring mirrors. So, eventually, the mirrors dropped off the sides of the "light-tunnel" and reduced the amount of light reaching the DLP chip. The color-wheel was the 2nd problem -- it used a stepper-motor to "align" the colors with the DLP chip, which was completely ridiculous -- all it took to screw that up was one little glitch in the stepper-motor, and suddenly the colors weren't aligned properly with the picture that the DLP chip was displaying, so everything looked like a rainbow. After 3 years or so, the set was so badly compromised, that I had to toss it out and buy a new TV. Really ticked me off, too, because when it was brand-new it had a picture that was far better than any LCD or Plasma set of its day. I wish they had designed that set better.

[@shivajisuryavanshisss]

Awesome explanation

[@insightfool]

Wow! Such a great explanation once again, Ben! Thanks.

[@Sorenzo]

Once took one of these apart and couldn't figure out how it worked. Thanks for the explainer :)

[@fiantop8]

Amazing explanation. Thanks for sharing! :)

[@Kaushalvisrolia]

Such a Great job.

[@EuroScot2023]

Excellent work.

[@satanshollowd]

This is awesome! I kinda fancy having a go at making the macro scale one. Would love to see what you make of it

[@Qual_]

Very informative, even 5years later. Thank you.

[@rubenllb7037]

Coolest thing I've seen in a while. I had no clue how it worked. Thanks

[@BrianPhelpsV2]

Great video Ben!

[@MaxKoschuh]

Great video. And Mike..... is everywhere!!!

[@Edward135i]

for some reason this is even more amazing to me than a microprocessor, how do you make a mirror that small, how do you make that something mechanical this small operate reliably, probably millions of DLP projectors that have been running for 20 years now still out there still working.

[@tessierm1222]

Ah, great explanation, Thank you!

[@middleclassseabass7178]

Awesome video, very cool. I'm surprised you don't have more subscribers. Your videos are some of the most interesting and informative videos on KZbin.

[@JamesPound]

Wow. That was fascinating

[@EricCosner]

Really enjoyed watching every second of this! It’s amazing what these DLP chips do. That Dell projector was my first DLP! It’s fascinating the similarities to camera sensors and I wonder why they don’t use tiny color filters over slightly smaller mirrors to actually make individual RGB pixels instead of using a color wheel. Our current projector does 3D and it’s interesting how that work as these tiny mirrors are in sync with the shutter glasses. Sometimes I do see the rainbow effect from the color wheel but it doesn’t bother me much. 😄

[@adamkmcneish]

Ben, your channel is sweet. It's like a modern, more technical version of an old favorite of mine The Secret Life of Machines.

[@movax20h]

Nice video. Every time I think about DLP and moving mirrors I think about the sound they make. But well, they move so fast, and they are only 10um in size that I do not think they make any real sound... I think having macro-DLP working would be cool. Even monochromatic one!

[@sushibobagenius9813]

Really, extremely, fully usefulllll! God bless you and everyone! An interesting way to explain and very clear! Thank you so much!

[@DjGen0]

You would make a very good teacher.

[@mastat2868]

impressive work! thank you!