E-paper displays (EPD), also known as e-ink displays, are familiar to many customers today from e-book readers or retail price tags. E-paper displays reflect light like normal paper, i.e. they are passive displays in which the content (text or images) is permanently displayed. Since no maintenance voltage is required for this, the energy consumption of these displays is close to zero; a power source is only required when changing the image content. For this reason, EPDs are particularly suitable for self-sufficient applications that are powered by batteries or solar cells. Another advantage is the excellent readability; even in direct light, EPDs are clearly visible at all times. This is of great importance in the area of digital advertising or price labeling, for example.