How Etulipa Sees Future Billboards Being E-Paper-Based And Solar-Powered

August 3, 2022 by Dave Haynes

E-paper displays are, by far, best known for the little e-readers people use instead of printed books. The core technology used for those readers is what’s also being used for things like meeting room displays and updated bus stop schedule signs that run off batteries and, in some cases, solar chargers. But that’s all been in black and white and gray. Color displays, and particularly displays that can do full motion graphics and video playback, have largely stayed in the bucket of future technology.

A small Dutch company is well along the path of changing all that – using something called electro-wetting display technology that gets its brightness from the sun, and would be used as low-energy alternatives to big LED video displays used for out of home advertising.

In this podcast, I have a detailed chat with Etulipa founder Hans Feil, whose company is rapidly evolving and maturing the technology, and has a big investment and R&D partner in Daktronics, the big South Dakota-based LED manufacturer. We get into what the technology is and how it works, its differences with other kinds of e-paper, how it sets up, and its benefits.

The company is still at the advanced R&D stage, but far enough along that it anticipates being in small quantity production next year, through a manufacturing partner in Taiwan.

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Hans, thank you very much for joining me. Let’s just get right to it. What the heck is electro wetting display technology? 

Hans Feil: That’s a good question. It’s what they call reflective display technology. Of course, you probably know about it already, but if people don’t know, the introduction that I made is that I say you probably will have an e-reader, many people have e-readers nowadays and it’s black and white and a little bit slow, but you can read it outdoors. If you take your iPad outdoor in the sun, it’s difficult to read. We have something like your the display on the e-reader, but then with color and it’s fast, and that’s the that’s the difference.

So it’s a reflective display technology. It reflects light so there’s no back light behind, it doesn’t emit light. So if you take our display into the dark, you don’t see anything unless you light it up with a back light or front light. So that’s for newcomers. If you’re a chemist or a physicist or a scientist, I’d probably say it a little bit different, in the sense that what we do is that we manipulates liquids colored oils, and we have a layer colored oils and with little cells with oils and we can make small droplets with it and the size of the droplets we can. 

For instance, if you compare to print, many people have ink-jet printers and if they would take a magnifying glass and look at the paper, they’re see little cyan, magenta and yellow droplets on the white paper, and what we do is we’re mimicking this printing with cyan, magenta and yellow. So we have a white paper or white reflector, we call it. And we have three layers of glass on top of it with cyan, magenta, and yellow oil and each individual layer, we can switch this oil droplets, making them small or big. And if all the layers are spread, it’s black because you don’t see anything, all the lights are absorb. And if there are all the droplets are small, white or nearly white and depending on which droplets you switch and can get all the colors of the rainbow, and that’s all very low power. 

From what I read on your website, unlike traditional, if you wanna call traditional ePaper, what we would know from E-ink displays primarily, this can do 25 frames per second motion, which is quite a bit different because when you see something change on an ePaper screen, it goes nuts for a fraction of a second as it reorganizes itself. 

Hans Feil: Yes, and in our case, it doesn’t really reorganize, droplets just become big or small and it goes very fast. 

Was that a big step to get to the point where you could change them that quickly or is that kind of inherent in the technology design? 

Hans Feil: It comes automatically with the technology. It has never been slow. 

And with ePaper, and I’m certainly not banging on Eink, but they spent 20+ years advancing their color displays and they’ll put out press releases saying we now have more color support than we used to but basically it’s been a very long road to get ’em to full color. 

You’re saying you’ve got full color gamut right now? 

Hans Feil: Yes, but also in our case, it was a very long long route too. The first paper of Rob Hayes and Johan Feenstra from Phillips Research was from 2003, so 19 years ago, this nature paper, where they’re first showing to the world electro wetting display, or at least the concept and some examples. So that’s 19 years ago and since then we are working very hard on progressing technology, making better making it possible to manufacture displays and so forth. So it’s also a very long route. 

So what’s the tie, if there is one to Phillips? 

Hans Feil: Right now, there is no tie except that we are located here in Eindhoven, what they call High Tech Campus, Eindhoven and it used to be the same campus, but smaller from Phillips Research in the old days. So the technology originally, the effect of switching oil droppers, was initially invented here a few hundreds of meters a away from the place where I’m standing now. 

Am I remembering correctly that you have a background with Phillips as well?

Hans Feil: That’s correct, yeah. I worked what they call the Phillips Research Labs since 1988 in various functions, but mostly quite scientific work in the old days, when it was a very scientific lab. And then I worked for a number of years in battery technology, lithium polymer batteries, and by the end of the 90s, and I got in touch of the guys who started this electro wetting displays, I think in 2004, so I’m 18 years active in electro wetting displays already. 

So like you said, it has been a bit of a road then? 

Hans Feil: Yes, sure.  

When did Etulipa start? 

Hans Feil: I’ll share a bit of history. At Phillips, when we were working on electro wetting display technology, we did a spinoff called Liquavista, you may have heard the name. It was early 2006 and a little bit prior to that, there was interest from the German automotive mirror manufacturer, a very big one, who wanted to see if this technology could be used for rear view auto dimming mirrors, and at that time it looked very promising.

In fact, after co-founding Liquavista, half a year later, together with an old colleague, I cofounded Miortech and Miortech was dedicated to use this electro wedding display technology for rearview mirrors. So by the end of 2006, we started this company, Miortech, trying to make the mirrors. Turned out to be that technology was not as fast as we hoped so there was a lot of development work to do. We really had to go back to the drawing table. In fact, we found out that there was a better way of making electro wetting displays with a different architecture that solved most of the initial problems. We patented that and then we started making prototypes of this mirrors, but basically it was a little bit too late, the market evolved and these automotive companies didn’t want to really want it anymore. 

But also in fact, if you’re trying to make a mirror with small oil droplets or small cells, there’s also always some light scattering from this droplets and so we could never get this mirrors fully free from haze. It was always a little bit of haze, so it was not good enough. So by the end of 2012, so it was almost 10 years ago, we said these mirrors are no good. It’s a display technology. We have our own patented way of making electro wetting displays, maybe there are display companies who are interested in, for instance, licensing this technology, the way that we make the devices. Turns out to be not so easy, but at some point of time, we were asked, “Can’t you make outdoor display with this technology?” And in fact, that’s the sweet spot of electro wetting display. 

If you really want to have bright, reflective colors, you need CMY, the stack of cyan, magenta, yellow. Just black and white display plus color filters is just not bright enough because you are throwing away two third of the light and so for reflective, you need CMY, and this stack has always a certain thickness because of the glass thickness, which also mean that it limits the the pixel density that you can reach. The rule of thumb is that the the thickness of the stack, CMY is roughly in the same range as the pixel size. And for outdoor displays, if you have a 10 millimeter pixels that’s pretty good, that’s pretty high resolution already. 

So we made a few samples with CMY, very simple samples. And we went along to outdoor display companies, including Daktronics at the time, it was 2013 or 2014 or something like that and we showed it to the folks at Daktronics and they liked it. So they said this looks promising, of course, it was very early days, we just had samples. But since then, we have worked together with Daktronics. They became a shareholder, supporting us all the way, step by step from small displays to black and white displays to full color displays that we have right now. So the story started in 2013, when we stopped the mirrors and said, okay, we need to move to outdoor displays with this, and I think it was a good bet. 

Did you find yourself going in the direction of outdoor displays because of market size or was it more the case of a company in Daktronics that specializes in large format, outdoor displays, was interested in it and therefore you had an automatic market partner? 

Hans Feil: No, the funny thing is, when we were still at Phillips and we were looking for what kind of markets we would first do with Liquavista, with the technology. I did some research on different markets and I found out that outdoor display markets was in the sweet spot of the technology. But then, and we are talking about 2005 or something like that, the venture capitalist who invested in Liquavista really want to go in mobile displays. So it was at a time when Nokia was still big and the market was growing so reflective displays for cell phones was the automatic market and we put aside the outdoor display at that time. 

So talking about my first PowerPoints I had and spreadsheet about market sizes for electro wedding displays for outdoor was already in 2005, so I had it always in my back of the minds and I had presentations ready when we made the switch. That’s the reason why we visited Daktronics and a few others. So we didn’t make the move to outward display just because of Daktronics, we had chosen for outdoor displays and it just fits with Daktronics. 

So just like LED displays, the kind that are manufactured by Daktronics primarily, these displays have a pixel pitch, correct?

Hans Feil: Correct. 

So there’s a gap between each pixel basically? 

Hans Feil:. Yes, they’re point sources, sort of. 

And right now it’s 10 millimeters, which in  LED terms would sometimes be referred to as P10 or something, but I’m reading that you anticipate that you can get it down to 2.5mm? 

Hans Feil: Yes, that’s correct. We already have made samples with TFT back planes with 2.5mm pixel pitch. So right now we have P10, so that are the first displays that we’re making but the next stop would be 2.5 millimeter and also larger tiles. 

At P10, that’s very competitive with conventional billboards that you would see on the side of a road and up above a building, that sort of thing. 2.5 means you could have it as a sidewalk level display that somebody would be able to view quite nicely from say 10 feet away?

Hans Feil: Yes, exactly, like bus stops, sidewalks and that kinda stuff. 

Yeah. Do you have to get even tighter than that, and is it possible if you wanted to do print and bus schedules and things like that? 

Hans Feil: If we want to go to smaller pixel sizes, what’s needed is somewhat thinner glass. So right now, the glass that we use is 0.5 millimeter and we have a stack of number of pieces of glass but if you go glass that’s 0.2 millimeter or 0.3 millimeter, we can go to pixel sizes of 1 or 1.5 millimeter. 

Is that something that’s possible, or it’s not even developed yet by the glass manufacturers?

Hans Feil: Oh no, the glass is there. There’s even thinner. Basically, we do it step by step, but the glass is there. 

So this isn’t a wish, it’s just a when? 

Hans Feil: Yeah, exactly. There are many things that are a when. 

These units are, again, similar in certain respects to LED displays in terms of they have cabinets or tiles, and they stack together?

Hans Feil: Correct. 

What are the sizes of these tiles, and are there limitations as to how many you can put together or is it modular and it can be as big as you want?

Hans Feil: It’s modular. The the tiles that we have right now are roughly 10 inch, and we have six tiles in one panel. That’s how we build the displays that we have here in our backyard. And the next step with 2.5 millimeter, we’re looking for 21 inch tiles so there’ll be bigger tiles and smaller pitch, but there are no limits in how big you can make the displays of it. It’s just metal scaling up the electronics and it’s all modular. 

With the video support, I read that right now you’re demonstrating animations and not full color video. Is there a reason for that or is just a matter that that’s what makes sense right now? 

Hans Feil: Yeah, that it’s mostly electronics development. There are two parts to this, one is the uniformity of the tiles. We are constantly improving the uniformity so the gray scales and the gray scale definitions become better and better, so that’s what’s needed, and the electronics development is a separate thing since we have to see how fast we can make the electronics work with the number of gray levels we have. Right now, it’s designed with 7 bits color so you can have 128 droplet sizes per color, which for reflective is very much, to be honest, the uniformity is not so good that we can really make this one on the 128 droplet sizes very precise. It’s a little bit less but that’s all about scaling up the electronics. 

In the advertising world, generally speaking for digital out-of-home advertising, they’re not using full motion anyways, except for spectaculars in Times Square and those big wrap arounds and so on. There’s one heck of a lot of deployed stock that is just digital posters basically?

Hans Feil: Yeah, for example, along freeways, you’re not allowed to do any animation and so on. 

So as long as you can address full color and have the clarity that people want, they’re happy? 

Hans Feil: Yeah, with the first display out here, it was a test for us to see what’s the color space that we can see, what’s the impression that we have, and so far we are quite happy. 

In fact, all the visitors that come along, many of them do not have very high expectations because they don’t know what to expect with reflective colors and the the veterans, so to say, who have seen reflective displays before, they know when colors are dull. But everybody was surprised when they walk outdoor and see what we have in terms of color and brightness. People are amazed. 

I believe I saw that these displays can handle 15,000 lumens, that’s the maximum brightness? 

Hans Feil: To be honest, we didn’t measure it exactly yet. That really depends on how much sun comes on it. It scales perfectly with the with the amount of sunshine in the environment. It’s like when you have newspaper, I don’t have to tell you, of course, that newspaper in the bright sun is very bright but because your eyes are accommodated to the brightness of the environment, you don’t do not really notice that it’s so bright and that’s the same with our display. 

In fact, here’s a funny story, the cameraman who made his shots for the video clip that we have, he was he was used to taking shots of video or display and he suddenly realizes that he didn’t have to adjust all his systems when the sun goes behind the cloud, the display didn’t become less bright because the trees and the grass, et cetera, also became less bright. It was then when he realized, okay this is different from what I’ve seen so far because LED displays are brighter compared to the surroundings all the time.

Yeah. It’s wildly different, it’s the opposite of outdoor LCDs, which are the primary things used for display totems to advertise street furniture, that kind of thing. They’re always battling the sun, they’ve gotta be at least 2500 nits to eve overpower glare and so on, and you’re saying, the brighter it is, the better it’s gonna get?

Hans Feil: Oh yeah, it’s fine. But also, today’s very gray weather here and I’ve been there with visitors when it was raining in and it still looked pretty good. It’s only when it’s getting really dark, likewhen the sun goes down, then you really notice. But it’s the same with your eReader. At some point of time, you realize, okay, now I do not see enough contrast anymore, I have to switch on my back light or front light or whatever you have. 

That backlight or front light, whatever it may be, that’s running off of a battery that’s charged by solar collectors, right?

Hans Feil: Yeah, that’s correct. 

So you can be completely autonomous from electrical power grid, but is there enough power out of that battery to do cellular connectivity for updates? 

Hans Feil: Yes, sure. In fact, the trailer that we have out here, that was designed to have an LED display mounted on it, so that there’s a little bit big battery, but it’s one solar panel, a lead acid batteries in this trailer. In fact, we have never charged this one, never. Previously we had a black and white display on it and with our color display, the power consumption of our display is so low, we don’t need to charge it.

One thing I noticed in the reference photos is that the units have seams. It reminds me of 5-10 years ago when the LCD manufacturers every year would come up with some definition or description of even narrower bezel or seams in between the displays, and when LED came along, that got of a lot interest just because the seams went away, and people who were designing spaces were saying, okay, I wanna use LED instead, because there are no seams.

Are you getting any pushback about that about the seams that exist and will those with time go away? 

Hans Feil: Pushback is a big word, but people do notice the seams, and although the seam here that we have here is smaller than the width of one pixel, so if you walk to the display, of course you see the seam, and we prefer to have narrow seams or no seams, but you can see the seams. If you walk away, they become less noticeable, and if you cannot discriminate between individual pixels anymore, then the seams are also becoming very thin or hardly visible.

With LED display, if you walk toward the display, at some point of time, you can see the individual LEDs, right? The image breaks down and it become little light dots. And in our case, you start noticing the seam more and more. If you’re really standing in front of it, of course you’ll see many seams, but when you walk away on to say 30-50 feet for P10 pixel then it’s hardly noticeable anymore. But again, of course, everybody wants to have thinner seams or no seams. So we have a program working on that to get them thinner, less noticeable. And also in future, when we go to larger tiles, seams will become thin. 

We had a big outdoor advertiser here in Holland who who used our 100 square meters screens with P10 pixels, and said that this solution would be good, and not to worry about the seams very much because for 100 square meter display, you’re standing 50 meters away or even more, and you won’t see the seams anymore. 

Where’s the product at, are you now shipping or is it still in R&D? 

Hans Feil: No, we are now in the testing phase. So we have it out here in the backyard. The next display will be made and shipped to South Dakota for evaluating by Daktronics and their customers. By the end of the year, we are targeting to have a production capacity with our partner, URT in Taiwan, for 50 square meters per year, which isstill not much, but it’s doable. And then early next year, we think the first display will be used by first customers here in the region because turns out there are parties that connected to us that have been waiting for low power display for many years but they couldn’t go anywhere because the only thing that they had was LED, right? And now they have this option which some of them were looking for it for many years already. 

We have a client who, every two years, was making calculations about power consumption of the display and every two years he was disappointed that it was never low enough, and now suddenly he got in touch with us and said, this is what I need. So he’ll probably use a number of our displays in the first half of next year. 

Are the upfront costs for this going to be higher than that for the upfront cost of conventional LED displays for the same footprint and are the savings more on the backend because you’re not using power?

Hans Feil: Yeah, that’s correct. Right now, we are making them in small quantities So the price is not really reflecting how it can be. But indeed, there is a huge savings in situations where people have to make a connection to the grid, which can take months before they can get a connection, and it’s also very often very expensive. We had one small, black and white display in a New York City bus stop, it turns out to be that the solution with our displays in that bus stop with a solar panel and a battery was 30% cheaper than the original version with LED displays, which were connected to the grid. 

This connection to the grid and all the work that, that goes along it and permits and so forth, make it very expensive. So even when there was a battery added and a solar panel added, and our display was more expensive than the LED one, it was much cheaper to have reflective displays. It was also new for us at that time. 

So going forward into 2023, if I am a outdoor media company in, let’s say Australia, and I want to buy this, am I going to be buying it through Daktronics, or will you be licensing this more broadly than that? 

Hans Feil: Most likely through Daktronics. Probably the first smaller smaller display here in the region, we will install ourselves because that’s more convenient, it’s nearby, et cetera. But once this becomes bigger and more mature, it’s our goal, our business plan that we will be creating the panels and Daktronics will make displays with those panels and sell them worldwide.

And as you scale up maybe the existing manufacturer in Taiwan who right now might be a contract manufacturer doing small lots, you would figure it out from there what kind of manufacturing capacity you’d need? 

Hans Feil: Yeah. So for now that they have enough capacity, there should be no problem.

We are open for talks, the whole consortium of URT, Daktronics and ourselves, if there are any other major display company who says, okay, I also want to adopt electro wetting displays, because we always believe if we want to make this successful, we should not really keep it all for ourselves.

And there’s lots of money to be made,-without a lot of grief-in licensing.

Hans Feil: Yeah, we’re open to do anything that’s reasonable. But there are many in fact, maybe all the major display companies that at some point of time tried making electro wetting displays and did R&D but they found it very difficult and stopped with it. 

We have our own technology, what we call second generation technology with different approach and we solved all those problems that were there with the first generation electro wetting displays. It has taken some time, but it’s worked quite well now.

I’m looking forward to seeing it at some point, somewhere. I hope I don’t have to go to South Dakota in the middle of the winter, but you never know. 

Hans Feil: Well, you could also come here, but I’m not sure if you are in Europe anytime soon. 

Yeah, well, Eindhoven has a better football team than Brookings South Dakota, so that would be a better trip for me. 

Anyway, thank you very much for spending some time with me.

Hans Feil: Yeah, I’m very glad that I got opportunity from you to talk about this. And I hope you can watch our display anytime soon, either here or in the US somewhere. Seeing is believing, in fact, and reflective is just different. 

Yeah. I completely buy into the idea that it’s one of those things that it’s interesting to read and to hear about in a podcast, but to walk up and see it is where you’re gonna close the deal.

Hans Feil: Yeah, exactly. 

All right, thanks again.

Hans Feil: Thank you very much, and hope to see you soon.

  1. John philippson says:

    Great read.

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