New Eval Tools May Simplify E-Paper Design, the Low-Power Cousin of LCDs

February 17, 2021 by Jake Hertz

As more engineering teams look to incorporate e-paper displays into their products, proper evaluation tools can help designers cut power and boost memory.

Electrical engineers are constantly tasked with cutting down on power consumption. While many techniques often focus on processing and data movement to lower power consumption, display technologies also account for a significant amount of energy draw. 


Consumer device power consumption has been trending downwards for years

Consumer device power consumption has been trending downwards for years. Image used courtesy of Andrae et al. and MDPI

One display technology called e-paper (commonly associated with Amazon's e-reader devices) has been growing in popularity because it is a lower-power alternative to LCDs. One e-paper-focused company Pervasive Displays recently released an extension kit and evaluation board to ease engineers' power concerns when implementing this technology.


E-Paper for Low Power 

E-paper operates in a fundamentally different way than standard LCD or OLED displays. As AAC contributor Gary Elinoff explains, e-paper displays images with pixels that consist of “ink” particles arranged in rows and columns suspended in a clear fluid.

These “ink” particles are electrically polarized such that when excited with an external charge, the desired “ink” particle rises to the display’s surface. 


E-paper offers better visibility outdoors than LCD displays

E-paper offers better visibility outdoors than LCD displays. Images (modified) used courtesy of Ken’s Tech Tips

One of the important features of e-paper is that no power consumption is required to maintain an image, and an image will remain on the display even when power is removed. The only time these displays consume electricity is when images are changing. LCDs, on the other hand, require a backlight to display an image, consuming significant amounts of power. 


Power consumption breakdown of a “typical” computer

Power consumption breakdown of a “typical” computer. Image used courtesy of Intel

This is extremely important in the world of low-power electronics, since a computer’s LCD, for example, can be the single biggest contributor to the device’s power consumption. 


A New E-Paper Extension Kit and Eval Board

This week, Pervasive Displays announced a new product that it hopes will make e-paper system development much simpler for designers.

The company's third generation e-paper extension kit and evaluation board, dubbed EXT3, is designed to provide engineers with a simple and convenient host MCU interface. This board is specifically compatible with any display using the company’s internal timing controller (iTC) technology. In addition, the EXT3 includes open-source software resources, allowing design teams to easily evaluate their displays. 


Pervasive EXT3 graphic

Pervasive EXT3 graphic. Image used courtesy of Pervasive Displays

From a hardware perspective, the board notably includes a 1 MB flash memory along with an expansion pad if more memory is required. 


Simplifying Display Designs

The goal of this new board is to simplify engineering design decisions around e-paper and decrease time to market. The MCU interface speaks to this goal by allowing engineers to easily test different MCUs with a variety of e-paper displays. The memory expansion pad also allows engineers to test the best possible memory options in collaboration with its MCU. 

According to Pervasive Displays, the EXT3 may help engineers determine the best combination of MCU, display, and memory for their system. This capacity to cut down on power-hungry components in a display device may also lead to longer battery life and smaller form factors, which are increasingly important design features in IoT devices.

1 Comment
  • uwezi May 11, 2021

    E-paper displays are still about 10x more expensive than monochrome reflective or transmissive LCDs, 5x more expensive than monochrome OLEDs - at least for the hobbyist and maker market. I wonder what causes this price difference since the drive electronics and manufacturing process are at least described as very similar?

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