Have You Ever Seen an E Ink Display Update This Quickly? By GSeph Electronics

As, a self-proclaimed e-ink expert, I talk about e-ink. Quite a lot. I've written a few articles done a load of different videos on them, but one of the things I never really do is actually show the displays working. I always talk about the theory behind it or how the technology works, but unless I'm doing a video on a specific display, I very rarely actually show what they look like and what they're capable of so in this video, I'm going to show a bunch of different inks plays what they can do and particularly how far they've come since the technology was invented. So without further ado, let's get started we're going to start by looking at the most commonly found. E-Ink displays, simple, AIDS or all-in-one displays.

These are very easy to get running, requiring only a simple three-wire, SPI interface and some control signals most maker projects that I see use these kinds of displays. They only need a few external components to work, a bunch of decoupling capacitors and some diodes and an inductor which work as external components to the onboard dc converter. These displays are cheap. If you have a glass-backed one rather than a flexible plastic-backed one and are very easy to use from what I've seen simple AIO displays are always black and white only have relatively slow update times, usually around one to two seconds and are only capable of performing full updates on the entire display. So that means no windowed updates and no partial updates.

Partial updates are updates. That can happen instantly rather than flashing black and white a few times and windowed updates that can occur in a windowed area rather than across the entire display. If you haven't seen my intro to e-ink video over on the enter channel and want to get a better understanding of how the technology works, then I highly recommend going over there and having a look. These displays are typically aimed at shelf labeling applications or logistics labels due to their slow update, speeds they're for updating once a day or once a week, but don't lend themselves to applications that require fast updates, such as applications that respond to user input. You'll notice as well that these demos are running on invited e-ink explained pro boards.

These are actually being discontinued and being replaced with something way, cooler and much more interesting for makers, but I can't say too much about it just yet so make sure you subscribe. So you don't miss on that when I can finally talk about them here, we have a 2.9 inch display on the left, a 5.7 inch display in the top right. This is the largest all-in-one display you can get and a small 1.5 inch display in the bottom right and the display in the middle at the bottom is just the same.2.9 inch display next up, we have complex all-in-one displays. These are still simple in that they use a 3-wire SPI interface, some control signals and only require a minimal number of external components, but they are much more capable allowing for two or four bit grayscale and partial updates and in some cases, windowed updates as well. They also require their update waveforms to be loaded by the host microcontroller, making them a bit more complex to run and requiring an external flash chip.

Without going into too much detail, the update waveforms dictate exactly how a display needs to update down to what voltage needs to be sent to each electrode and at what time. But we don't need to understand exactly how they work just that they exist and need to be loaded prior to updating, simple AIDS already have these waveforms programmed into the onboard controller. Here we have a 2.8 inch display on the top left, a 1.1 inch smartwatch display in the middle, a 3.7 inch display on the right and a 1.3 inch display on the bottom left. We can see the 2.8 inch display perform a full update, and you can see that this is fairly fast in comparison to the one to two-second updates. We saw on the simple AIO displays.

This is then followed by a windowed update, switching the text between john d and in progress, and this is performing a full update, which is why it flicks to black for a moment, but only in a windowed area. If we then look at the 1.1 inch display in the middle, we can see. The full update again is quite quick, and we can then see it counting up by performing partial updates, so the change is instantaneous. Partial updates are quicker to perform and look nicer, but they often leave a ghosted image of what was there before, and this is the trade-off. It's update.

Quality versus update speed, since this 1.1 inch display is designed for smartwatches, being able to perform partial updates is vital, especially if you plan to change the time display every minute. You want to do this as discretely as possible, rather than flashing black and white a few times and continually drawing the user's attention. Unlike the simple all-in-one displays that we saw because of the fast update times and the grayscale capabilities, these displays are typically aimed at applications that respond to user input. Next up are colored e ink displays, you'll, recognize the 5.7 inch. Seven color display from previous videos.

I've done and in the middle at the bottom is a 2.9 inch. Black white and red display and in the bottom right is the newly released four inches. Seven color display three color displays are generally black, one red or black white and yellow and seven color displays are black white, red, green and blue, yellow and orange. But as mentioned in the videos I did before, these colors cannot be blended, and so you have to dither the images to achieve different colors, which doesn't always work out too well, due to the way the technology works, there's simply no fast way to update a colored e-ink display, and so these displays are pretty much entirely aimed at signage applications, since ciceroni's inky impression was released. I've seen loads of people use these for desktop calendars and displays showing covered statistics, and I think that's a really awesome use for this kind of colored displays where update time.

Just isn't that important. All of these colored displays are simple: AIO displays, which means no update, waveforms and only minimal circuitry. You can get more complex, colored displays, but these are typically quite large, and I'm not going to be covering them in this video next up we have segmented ink displays. I think these are talked about the least of any type of display, but they're very simple, to run and also quite cheap, just like in led or LCD segmented displays. These can come with custom designs or as an off the shelf module and the e-ink splays can be driven without a dedicated display driver requiring either a 5 volt supply which most microcontrollers with built-in display drivers can output or a 15 volt supply for faster, clearer updates.

Some microcontrollers can drive ends with a 15 volt supply, but they're a lot less common to find Epson, for example, does a range of them, but as far as I've seen they're the only people I know on the left hand, side is a single segment e-ink display that is made from an e-ink fabric with red and white particles in this was a proof of concept. Ian did for smoke, alarms to act as a fault indicator. The idea was that, when the maintenance person needs to check the status of the smoke alarms in a place like a warehouse or a university, that has lots of them, they can simply look for the alarm that has the red indicator showing and because it's e-ink, rather than a red LED, which is typically used. It can consume zero power while showing what the status is in the middle. We have a 2.5 digit seven segment display underneath is a 14 segment bar display useful for battery statuses or level indicators. Top right is a six digit, seven segment display and on the right connected to the ex segmented quick start kit is a three digit seven segment display with a percentage symbol.

The quick start kit drives the display with a five volt update and at the moment I'm applying the voltages for two seconds for an update. The red LED indicates that an update's in progress- and you can see this- produces a nice clear update. I can also add the percentage symbol in here as well. If I now reconfigure the software to apply this voltage for 500 milliseconds instead of 2 seconds, we'll obviously get a faster update, but you can see that the quality of the update really isn't very good. The contrast of the digit is pretty poor with a 15 volt supply.

However, you can drive the update for as little as a few hundred milliseconds and get a nice clear, well contrasted update, just as with the active matrix displays, we can perform a full update on the entire display and produce that nice clear result, but again it's slower than performing direct updates and shows that transition that flips between black and white states a few times. The final type of display we're going to look at are externally controlled displays. These have all their components external to the panel rather than built into the controller on the chip on glass. These displays are more expensive to buy and run, but are significantly more capable than the other types of displays we've seen so far, just like complex AIDS, they require external waveforms to be loaded, but they also require an external timing, controller mic, flash memory and temperature sensor. However, their updates are fast.

They support multiple update modes, including partial updates, and are also capable of windowed updates. They come in a range of sizes from 4 inches to 42, inches support, 4-bit grayscale, unless you get a colored display, and they are very well suited for UI interface. Applications like the Amazon Kindle. Interestingly, the speed of the updates on the externally controlled displays is basically the same regardless of size. Here we have a 7.8 inch display on the left, a 6-inch display on the right and a 4.3 inch display in the middle, starting with the 4.3 inch display. We can see some very fast partial updates being performed as the counter increments, really showing the difference in performance in comparison to the simple AIDS we saw at the beginning, we'll also see a windowed update demo, so in a sec, we'll see a full update formed in just that outlined area.

The reason we need to perform a full update is because we're displaying a grayscale image and partial updates can only be performed on transitions to solid black or solid white. There are other update modes that can speed up the transition to a grayscale image, but, as I mentioned before, they do this at the expense of quality, and these updates already update quickly as it is next up, is the 7.8 inch display. We can see a fast update, followed by some nice, clear, partial updates as the counter increments, like I said before, regardless of size, these displays all update in pretty much the same amount of time. The partial updates on this are running a bit slower than on the 4.3 inch demo, but this is only because of the dodgy software I put together and not because of the panel's capabilities. Finally, I wanted to show you guys a proof of concept that IAN have put together to show the capabilities of these displays.

This is me note or mobile extendable enough, and it runs on their newly released end controller. This is particularly special because ex controller has a built-in micro that allows direct manipulation of the display without requiring an external host. The demo here isn't particularly special as it's just showing a drawing application similar to on a remarkable tablet, but it's firstly showing how quickly the changes to the display are, but we can also see that if we clear the display, you can see the ghosting effect left behind due to performing partial updates, which we discussed earlier. We can remove this completely by performing a full update. The fascinating thing about this demo, however, is some software that IAN have put together that allow you to mirror the display from a computer to provide real-time writing capabilities on the e-ink tablet.

Their aim with this demo is to show how e-paper displays can be used for annotating documents or for e-learning in classrooms without the user having to deal with the eye strain of staring at a backlit screen all day. Of course, this is just a concept and the PC could easily be replaced with a soc using the e-ink display as the primary monitor when connected to the PC. The system connects to e-ink software to control the updates, but it also is detected as a stylus device. So all the handwriting software built into windows and office just automatically works as I'm demoing. This, what's not obvious, is the way the display is actually being updated.

I mentioned before the e-ink's end controller. Has a built-in MCU with direct access to the display, and what's happening is that when the stylus touches down the display is being updated by the controller and also writing on the PC. At the same time when the stylus is lifted, the display is then updated by the software to reflect the actual changes to the screen. This is built-in functionality called direct handwrite, and it allows for super low, latency updates. I can show this more easily if I select the highlighter in PowerPoint.

When I move the stylus, you can see that in PowerPoint this is correctly drawing as a highlighter, but on the e display it's being drawn as a black line. It's not until I lift the stylus off the screen that the display updates to reflect what's actually been drawn. There are controls to configure what size pen is drawn by direct handwrite, and if we wanted to develop this further, we could edit the driving software to automatically change the size of the direct handwrites updates to reflect the pen chosen in PowerPoint or whatever program we're using. The only thing we couldn't do is draw a grayscale line since, as I said before, partial updates can't be performed on shades of gray. It's also probably best not performed on grayscale updates, as you can clearly see, ghosting from direct handwrites black line.

This is obviously quite a niche example of an application using ink displays, but I want to show it to you anyway, just to show how far we've come with the ink technology. But that's all I've got to show you guys today. If you like, the video, then leave a thumbs up, make sure you get subscribed for more content. If you have any questions or comments, leave them down below, and I'll see you guys in the next one.

Source : GSeph Electronics