Key points of using electronic paper

How does an e-Paper work? Electronic paper is the movement of countless balls in an electric field to display content. Here are some key points to use e-paper.

 > Key points of using electronic paper


E-paper is a very special display that has ultra-low power consumption, is readable under strong light, and protects the eyes. What are the advantages and disadvantages of electronic paper?

1.Pros and Cons of e-Paper

2.How to drive e-paper

Pros and Cons of e-Paper

As a special display, electronic paper has its own characteristics:

1. Without refreshing the screen, it does not consume power and can display one kind of content for a long time
2. Have the same reading experience as a real book
3. It can be normally displayed under strong light without affecting the display effect
4. Great viewing Angle
5. Thinner and lighter than OLED

But there are also disadvantages:
1. The refresh speed is slow
2. It cannot be displayed without ambient light
3. The price is relatively high
4. Color e-paper already exists, but it doesn’t work as well as other types of displays
How to use e-paper? Hopefully, the following key points will help you.

Black, white and red electronic paper

Black, white and red e-paper, can display three colors, does not support local refresh, page refresh takes 18s.

Black and white electronic paper

Black and white electronic paper

Black and white e-paper, can display two colors, support partial refresh, all page refresh needs 2s, partial refresh needs 500ms at the earliest.

How to drive e-paper

1, the screen write data 0x00 represents black, write data 0xFF represents white (note: black, white and red electronic paper 0xff represents red).

2. The screen needs to judge whether it is Busy every time when data is updated. When the busy pin level is low, data is updated.

3. The screen must be repositioned each time a new display interface is configured. In this case, re-call the OLED_GUIInit () function, otherwise the display will be distorted.

4, black and white electronic paper supports screen local refresh, but the image residue is serious in the process of refresh, black, white and red electronic paper does not support local refresh, so the program configuration uses picture array to map the display area, after initializing the screen, set the picture and call the Paint_NewImage function to map the display area and control the display direction. Call the OLED_Display function when the data is updated to display, otherwise nothing will appear.

5. The black, white and red three-color electronic paper screen is controlled by writing data to the 0x24 register. Red control is achieved by writing data to register 0x26; In order to ensure the consistency of input data, the mapping to the screen is reversed when writing data, and the red is data 0x00;

6. It is normal for the electronic paper screen to flicker during the refresh process, and you need to wait patiently for the final display effect.

7. The refresh rate of electronic paper is relatively low. The refresh rate of black and white electronic paper takes about 2s and that of black, white and red electronic paper takes about 18s, so electronic paper is suitable for displaying fixed pictures for a long time.

8. Touch screen can also be added to electronic paper. We have mastered the technology of fully fitting electronic paper to touch screen, and multi-touch can also be realized in the case of real book reading experience.

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