Forums

e-Ink and other paper like displays

Started by Rick C May 19, 2020
I have periodically reviewed the e-Ink market looking for usable products without a lot of experimentation.  Most of what I find are displays without driver boards, a few high priced combos of displays with separate driver boards, but few docs and very few displays an driver boards with some sort of docs and/or library support.  The one thing that always seems to be missing is an easy to find and easy to read document describing exactly what they will do and what they won't do.  Mostly the docs are a couple of poorly made videos with no real explanation.  

I saw one video (don't recall the vendor or site) showing a display with partial updates such as would be needed for a display of a real time device such as a... ventilator for example.  That looks promising.  But the display is monochrome and I still didn't find any docs on exactly how it would be interfaced to a system.  

My main interest in them is to provide a display optimally viewable in any lighting.  

There seems to be more than one manufacturer of these displays.  When they are sold by third parties (mostly through Aliexpress) it is hard to tell which brand of display they are.  If I understand correctly one company owns the patents with multiple manufacturers licensing.  

All of the inexpensive displays are pretty tiny.  One maker includes touch screens even on 1.5 inch displays!  My finger tip is not much smaller than that.  The prices rise rapidly with size.  A 4 inch display is pushing $40.  

Anyone used any of these displays?  Anyone happy with these displays?  Tips?  Cautions? 

-- 

  Rick C.

  - Get 1,000 miles of free Supercharging
  - Tesla referral code - https://ts.la/richard11209
On 20/05/2020 02:35, Rick C wrote:
> I have periodically reviewed the e-Ink market looking for usable products without a lot of experimentation. Most of what I find are displays without driver boards, a few high priced combos of displays with separate driver boards, but few docs and very few displays an driver boards with some sort of docs and/or library support. The one thing that always seems to be missing is an easy to find and easy to read document describing exactly what they will do and what they won't do. Mostly the docs are a couple of poorly made videos with no real explanation. > > I saw one video (don't recall the vendor or site) showing a display with partial updates such as would be needed for a display of a real time device such as a... ventilator for example. That looks promising. But the display is monochrome and I still didn't find any docs on exactly how it would be interfaced to a system. > > My main interest in them is to provide a display optimally viewable in any lighting. > > There seems to be more than one manufacturer of these displays. When they are sold by third parties (mostly through Aliexpress) it is hard to tell which brand of display they are. If I understand correctly one company owns the patents with multiple manufacturers licensing. > > All of the inexpensive displays are pretty tiny. One maker includes touch screens even on 1.5 inch displays! My finger tip is not much smaller than that. The prices rise rapidly with size. A 4 inch display is pushing $40. > > Anyone used any of these displays? Anyone happy with these displays? Tips? Cautions? >
I have only seen them on a couple of evaluation boards - I haven't had use of them myself. The advantages of them are very low power, high resolution (if you want, and pay for it), and readability in sunlight. But they are /slow/. They are often too slow for "real time devices" - if you use e-ink for a digital clock, for example, it will feel sluggish on the seconds digits. For good viewing in a wide range of lighting, also look at OLED displays. These can be very nice, high resolution, full colour, and give more brightness for the power than backlit LEDs. But no display technology is ideal for /all/ lighting conditions - there will always be some compromise. Really, to test the display in different lighting, there is no substitute to getting some demo boards and looking at them.
On Wednesday, May 20, 2020 at 2:48:38 AM UTC-4, David Brown wrote:
> On 20/05/2020 02:35, Rick C wrote: > > I have periodically reviewed the e-Ink market looking for usable products without a lot of experimentation. Most of what I find are displays without driver boards, a few high priced combos of displays with separate driver boards, but few docs and very few displays an driver boards with some sort of docs and/or library support. The one thing that always seems to be missing is an easy to find and easy to read document describing exactly what they will do and what they won't do. Mostly the docs are a couple of poorly made videos with no real explanation. > > > > I saw one video (don't recall the vendor or site) showing a display with partial updates such as would be needed for a display of a real time device such as a... ventilator for example. That looks promising. But the display is monochrome and I still didn't find any docs on exactly how it would be interfaced to a system. > > > > My main interest in them is to provide a display optimally viewable in any lighting. > > > > There seems to be more than one manufacturer of these displays. When they are sold by third parties (mostly through Aliexpress) it is hard to tell which brand of display they are. If I understand correctly one company owns the patents with multiple manufacturers licensing. > > > > All of the inexpensive displays are pretty tiny. One maker includes touch screens even on 1.5 inch displays! My finger tip is not much smaller than that. The prices rise rapidly with size. A 4 inch display is pushing $40. > > > > Anyone used any of these displays? Anyone happy with these displays? Tips? Cautions? > > > > I have only seen them on a couple of evaluation boards - I haven't had > use of them myself. > > The advantages of them are very low power, high resolution (if you want, > and pay for it), and readability in sunlight. But they are /slow/. > They are often too slow for "real time devices" - if you use e-ink for a > digital clock, for example, it will feel sluggish on the seconds digits.
I recently saw a video of a display updating a value once per second. That's not a problem unless you want to update the entire screen. They've had partial update for a while now. The three color displays are very slow requiring many passes and many seconds to update the display.
> For good viewing in a wide range of lighting, also look at OLED > displays. These can be very nice, high resolution, full colour, and > give more brightness for the power than backlit LEDs. But no display > technology is ideal for /all/ lighting conditions - there will always be > some compromise.
It is not required to be highly visible in the dark. Just like paper external light is required for eInk. Even so, I recently saw front lighted displays listed somewhere.
> Really, to test the display in different lighting, there is no > substitute to getting some demo boards and looking at them.
I don't need to do a look test on e-paper. It works. What I am looking for info on is how to drive them from an MCU. It used to be that a separate driver board was used since there are a few voltages that are required and some other details I don't fully understand. This time around I see the displays from Adafruit which seem to combine that interface with the display. They aren't really commercial units though. They clearly gave no thought to how they might be mounted and I think they have components on the same side of the board as the display, or that may have been another company. It's kind of weird that there is very little structure to the market. When you buy an MCU board they give lots of details and you know exactly who made each part and where to get good info on using it all. The eInk display products come from multiple display producers and they are not all the same at all. None of them provide very good support or documentation. I remember once contacting one of the display makers asking for more details on building an interface for their units. They just told me all the information was in the data sheet and that I should buy the controller boards. -- Rick C. + Get 1,000 miles of free Supercharging + Tesla referral code - https://ts.la/richard11209
Rick C <gnuarm.deletethisbit@gmail.com> wrote:

> Anyone used any of these displays? Anyone happy with these displays? > Tips? Cautions?
Not as a developer, but I own a Kindle. Both contrast and readability are great, but refresh time is very slow compared to other technologies. Cool temperatures seem to increase this time even more. You also have traces of previously shown picture unless you do a full erase / redraw (which decreases refresh time even more). If you want a display readable in varying conditions, maybe think of a VFD instead? -- https://www.youtube.com/watch?v=9lSzL1DqQn0
Rick C <gnuarm.deletethisbit@gmail.com> wrote:
> I don't need to do a look test on e-paper. It works. What I am looking > for info on is how to drive them from an MCU. It used to be that a > separate driver board was used since there are a few voltages that are > required and some other details I don't fully understand. This time > around I see the displays from Adafruit which seem to combine that > interface with the display. They aren't really commercial units though. > They clearly gave no thought to how they might be mounted and I think they > have components on the same side of the board as the display, or that may > have been another company.
As well as the strange negative voltages they need very specific timings to drive the internal elements. Those timings are usually secret and proprietary to the display, and possibly damage it if you get them wrong. You would need a CPLD or FPGA to act as a timing converter (TCON), but you can't build one because the timings are not published. Presumably Adafruit, Waveshare and friends have them under NDA and wrap them up in an easier package, but they're you're stuck with their PCB design. The most standardised interface I've seen is the e-reader SoCs (eg iMX6SoloLite) which have a dedicated EPD controller. There is usually a firmware blob that provides the timing information - it is possible to download the firmware for an e-reader and extract the blob, but then you're on your own. Waveshare are one of the better sources of providing interface modules and info, by the way: https://www.waveshare.com/product/displays/e-paper.htm https://www.waveshare.com/wiki/Main_Page#OLEDs_.2F_LCDs
> It's kind of weird that there is very little structure to the market. > When you buy an MCU board they give lots of details and you know exactly > who made each part and where to get good info on using it all. The eInk > display products come from multiple display producers and they are not all > the same at all. None of them provide very good support or documentation.
If you're Amazon building the next Kindle, you can get the info. They aren't interested in selling one-offs. Theo
On 21/05/2020 09:44, Rick C wrote:
> On Wednesday, May 20, 2020 at 2:48:38 AM UTC-4, David Brown wrote: >> On 20/05/2020 02:35, Rick C wrote: >>> I have periodically reviewed the e-Ink market looking for usable >>> products without a lot of experimentation. Most of what I find >>> are displays without driver boards, a few high priced combos of >>> displays with separate driver boards, but few docs and very few >>> displays an driver boards with some sort of docs and/or library >>> support. The one thing that always seems to be missing is an >>> easy to find and easy to read document describing exactly what >>> they will do and what they won't do. Mostly the docs are a >>> couple of poorly made videos with no real explanation. >>> >>> I saw one video (don't recall the vendor or site) showing a >>> display with partial updates such as would be needed for a >>> display of a real time device such as a... ventilator for >>> example. That looks promising. But the display is monochrome >>> and I still didn't find any docs on exactly how it would be >>> interfaced to a system. >>> >>> My main interest in them is to provide a display optimally >>> viewable in any lighting. >>> >>> There seems to be more than one manufacturer of these displays. >>> When they are sold by third parties (mostly through Aliexpress) >>> it is hard to tell which brand of display they are. If I >>> understand correctly one company owns the patents with multiple >>> manufacturers licensing. >>> >>> All of the inexpensive displays are pretty tiny. One maker >>> includes touch screens even on 1.5 inch displays! My finger tip >>> is not much smaller than that. The prices rise rapidly with >>> size. A 4 inch display is pushing $40. >>> >>> Anyone used any of these displays? Anyone happy with these >>> displays? Tips? Cautions? >>> >> >> I have only seen them on a couple of evaluation boards - I haven't >> had use of them myself. >> >> The advantages of them are very low power, high resolution (if you >> want, and pay for it), and readability in sunlight. But they are >> /slow/. They are often too slow for "real time devices" - if you >> use e-ink for a digital clock, for example, it will feel sluggish >> on the seconds digits. > > I recently saw a video of a display updating a value once per second. > That's not a problem unless you want to update the entire screen. > They've had partial update for a while now. The three color displays > are very slow requiring many passes and many seconds to update the > display. >
I guess the technology has moved forward.
> >> For good viewing in a wide range of lighting, also look at OLED >> displays. These can be very nice, high resolution, full colour, >> and give more brightness for the power than backlit LEDs. But no >> display technology is ideal for /all/ lighting conditions - there >> will always be some compromise. > > It is not required to be highly visible in the dark. Just like paper > external light is required for eInk. Even so, I recently saw front > lighted displays listed somewhere. >
Front-lighting may be okay, but I think it would often be hard to get the angles right for an even lighting. Generally, e-Ink needs an external light source - if that's okay for the application, then great.
> >> Really, to test the display in different lighting, there is no >> substitute to getting some demo boards and looking at them. > > I don't need to do a look test on e-paper. It works. What I am > looking for info on is how to drive them from an MCU. It used to be > that a separate driver board was used since there are a few voltages > that are required and some other details I don't fully understand.
Fair enough. I'm afraid I can't be any help there - I haven't used them myself, and anything I could look up, you can look up too (and probably have). My general advice if the manufacturers are not giving good information would be to ask your favourite distributors for suggestions and data, but I expect you've thought of that already too! (And I am aware that the quality and helpfulness of distributors and FAE's varies a lot from country to country. We have several very good ones, but not everyone is that lucky.)
> This time around I see the displays from Adafruit which seem to > combine that interface with the display. They aren't really > commercial units though. They clearly gave no thought to how they > might be mounted and I think they have components on the same side of > the board as the display, or that may have been another company. >
I've found Adafruit to be a useful source for one-off devices, such as screens to fit with rpi's for test benches, but not for larger numbers of units or for when you need to do a lot of work to use the devices.
> It's kind of weird that there is very little structure to the market. > When you buy an MCU board they give lots of details and you know > exactly who made each part and where to get good info on using it > all. The eInk display products come from multiple display producers > and they are not all the same at all. None of them provide very good > support or documentation. >
I suspect that most e-Ink customers are huge - they can talk directly to the manufacturers, rather than having to use publicly available information.
> I remember once contacting one of the display makers asking for more > details on building an interface for their units. They just told me > all the information was in the data sheet and that I should buy the > controller boards. >
On Thursday, May 21, 2020 at 9:45:09 AM UTC-4, Queequeg wrote:
> Rick C <gnuarm.deletethisbit@gmail.com> wrote: > > > Anyone used any of these displays? Anyone happy with these displays? > > Tips? Cautions? > > Not as a developer, but I own a Kindle. Both contrast and readability are > great, but refresh time is very slow compared to other technologies. Cool > temperatures seem to increase this time even more. You also have traces of > previously shown picture unless you do a full erase / redraw (which > decreases refresh time even more). > > If you want a display readable in varying conditions, maybe think of a VFD > instead? > > -- > https://www.youtube.com/watch?v=9lSzL1DqQn0
We discussed displays the other day and I mentioned the VFD as an option, but there seems to be some preference for an LCD. I think there would be more interest in the eInk if people were more familiar with them. Your experience with the Kindle was probably some time ago. Displays are faster now and smaller units are faster still, then partial display updates are even faster yet. -- Rick C. -- Get 1,000 miles of free Supercharging -- Tesla referral code - https://ts.la/richard11209
On Tuesday, May 19, 2020 at 8:35:44 PM UTC-4, Rick C wrote:
> Anyone used any of these displays? Anyone happy with these displays? > Tips? Cautions?
I run a moving map program on a Kobo Glo (a nice Linux box, ~$50 on eBay). Some ghosting, but real-time updates of the map are quite acceptable. Fabulous screen outdoors in bright sunlight (this is in my plane). The controller is a very complicated beast and not like LCD. An OEM module may not have adequate update rate for some applications. Interesting stuff! Best Regards, Dave
On Friday, May 22, 2020 at 6:11:58 PM UTC-4, Dave Nadler wrote:
> On Tuesday, May 19, 2020 at 8:35:44 PM UTC-4, Rick C wrote: > > Anyone used any of these displays? Anyone happy with these displays? > > Tips? Cautions? > > I run a moving map program on a Kobo Glo (a nice Linux box, ~$50 on eBay). > Some ghosting, but real-time updates of the map are quite acceptable. > Fabulous screen outdoors in bright sunlight (this is in my plane). > > The controller is a very complicated beast and not like LCD. > An OEM module may not have adequate update rate for some applications. > > Interesting stuff! > Best Regards, Dave
We may have talked about this before. When you say "plane" do you mean a glider? I have a faint recollection of talking to someone who used an e-Ink display in a very tight cockpit in a glider. -- Rick C. -+ Get 1,000 miles of free Supercharging -+ Tesla referral code - https://ts.la/richard11209
On Friday, May 22, 2020 at 8:16:08 PM UTC-4, Rick C wrote:
> On Friday, May 22, 2020 at 6:11:58 PM UTC-4, Dave Nadler wrote: > > On Tuesday, May 19, 2020 at 8:35:44 PM UTC-4, Rick C wrote: > > > Anyone used any of these displays? Anyone happy with these displays? > > > Tips? Cautions? > > > > I run a moving map program on a Kobo Glo (a nice Linux box, ~$50 on eBay). > > Some ghosting, but real-time updates of the map are quite acceptable. > > Fabulous screen outdoors in bright sunlight (this is in my plane). > > > > The controller is a very complicated beast and not like LCD. > > An OEM module may not have adequate update rate for some applications. > > > > Interesting stuff! > > Best Regards, Dave > > We may have talked about this before. When you say "plane" do you mean > a glider? I have a faint recollection of talking to someone who used > an e-Ink display in a very tight cockpit in a glider.
Yup, here's a short movie: http://www.nadler.com/sn10/20160423_SN10_to_TopHat_in_ArcusM.MOV