This week, Pervasive Displays unveiled two large format e-paper displays (EPDs) that are designed for areas of high ambient light that would overwhelm traditional LED or LCD displays.
Unlike many competing e-paper displays, which can only display text and images in black and white, members of this group can also present information in yellow.
The two new displays in question, making the most of that yellow e-ink. Image from Pervasive Displays.
New Display Specs
- The 7.4-inch E2741GS081
- Active display area: 96.96 mm x 161.6 mm
- Pixel resolution: 480 x 800
- Pixel pitch: 0.202 x 0.202
- Pixel density: 126 dpi
- The 12.2-inch E2B98FS081
- Active display area: 237.6 mm x 190.08 mm
- Pixel resolution: 960 x 768
- Pixel pitch: 0.2475 x 0.2475
- Pixel density: 103 dpi
Both of these devices feature an internal timing controller (iTC). This reduces the amount of external circuitry and programming required, resulting in smaller and more easily used devices.
How e-Ink Displays Work
Each pixel, lined up in rows and columns, is a capsule containing black and white “ink” particles. The new Pervasive Display devices also contain pixels with white and yellow particles.
Each “ink” particle, black, white or yellow, responds to either a positive or negative charge, which is applied via an external electrode. When the charge is applied, the appropriate particle is brought to the surface of the display, and is thus viewed; either black, white or yellow.
An EPD pixel and its electrode. Image source from Pervasive Displays
Power Considerations for Remote Display Applications
EPDs are bistable. That means that once a pixel is rendered visible or invisible, it stays that way. Unlike LCDs or LEDs, no power is required to keep it in either state. For this reason, EPDs require far less operating power than the traditional displays.
This also means that power is only required when the message changes, enabling them to operate for extended lengths of time on a small battery.
What Makes e-Ink Displays Stand Apart
One of the distinguishing advantages of EPDs is that, unlike LCD or LED displays, they are not hampered by direct sunlight, but rather they are even more clearly viewable. This is because they do not give off light, but reflect it. In this, they are comparable images rendered in ink on paper. This is why you'll sometimes hear the term e-ink
For this reason, e-paper displays are a great display option for anywhere with high ambient light, especially the outdoors in direct sunlight. They are especially useful for outdoor store displays and for e-readers, which must be easily readable anywhere.
Pervasive Displays has also made a point of making e-paper displays for embedded applications, including a simple setup for Arduino projects.
Important e-Paper Use Cases
e-paper displays such as this are useful where the information being displayed does change, but infrequently. Examples of this situation include:
- Office meeting room schedule screens
- Bus stop real-time departure boards
- Retail signage
- Museum information placards
Of course, if power isn’t a major factor, the EPD’s message can be changed as often as is needed.
As Alchin Wang, the General Manager of Pervasive Displays, said in a press release, “The addition of yellow e-ink helps product and service designers on both fronts, thereby supporting better customer experiences.”
Wang also points out that the Pervasive Display devices are viewable from very wide viewing angles, an important advantage in catching people’s attention.
Display Options on the Market
Pervasive Displays isn't alone in offering e-paper displays.
Crystalfontz features a wide range of EPDs, with sizes ranging from 200 x 200 resolution with a 1.54" diagonal active area to 640 x 384 resolution with a 7.5" active area. Available color combinations include: black and white and black and white with either red or yellow.
e-Ink offers the EC312TT2. This unit offers not two or three colors, but a remarkable 4096. This 31.2-inch display offers a display resolution of 1280 by 720 pixels.
If you've worked with any of these three companies' displays, tell us about your experience in the comments below.