With more research and more experience with my E-paper display, I started to realize that E-paper displays are great for certain projects and just not so good for others.
There are important things to know when choosing an E-paper display to be able to suceed with your project.
Choosing a display, the first thought would be big and colour, well those larger 3 colour displays may not be the right thing for you, it turns out that the more colours used could equate to a longer refresh time.
If you need to choose an E-paper display, then here is a list that you can use to research further.
- General issues with tricolour displays There is a minimum wait time between refreshes to prevent the display from dying or having image burn-in.
- Not only do you have to be aware of the time between refreshes, the display can show the same image for weeks or months but a refresh once in a while is still recommended to avoid some sort of “burn-in”.
- There is a longer refresh time on most tricolour displays, some can take 14 seconds to refresh fully, this is because it takes several seconds for each colour.
- Grey scale is not always available, and to get shading you might need to work around by useing a form of dithering an image to get shading.
- Some displays are not able to partial refresh only full refresh.
- The displays are fragile and subject to extremes of humidity & temperature well that could be said of a lot of displays, but still is a consideration.
- When buying the displays sometime the seller is selling only the glass and not the interface board, so you may need to buy separtately or design one.
- For ease of programming check if the common drivers for your processor and display size are available.
- Images can be converted and shown as a page and are more suitable for slide shows. It is possible to draw images with simple, dots, lines, triangles, squares and circles but it takes a bit of work to align everything.
Technology may get better, and some of these items listed could get resolved but the displays will probably be more expensive. Some people have demonstrated that it is possible modify their displays by changing the firmware in the display and change features but it is complex and comes with the possiblilty of damaging your display.