What is Electrowetting?

Electrowettting is a microfluidic phenomena that is currently enjoying strong growth as a driving mechanism for a wide range of fluidic and electro-optic applications.

Electrowetting modifies the surface tension of liquids on a solid surface by using a voltage. When a voltage is applied, the wetting properties of a hydrophobic surface can be modified and the surface becomes increasingly more hydrophilic (more wettable).

With Electrowetting displays, the modification of the surface tension is used to obtain a simple optical switch by contracting a colored oil film through applying a voltage. Without a voltage, the colored oil forms a continuous layer and the color is visible to the consumer. When a voltage applied, the oil is displaced and pixel becomes transparent. When various pixels are independently activated, the display can show any kind of content including text, images and video.

We can also use the transmissive pixel as the basis for reflective or transparent displays.

Thanks to the high switching speed of electrowetting and its applicability to small pixel dimensions, electrowetting displays support a fluent user interface and are ideally suited for information displays showing animated and video content.

Advantages

Outdoor/Indoor Usability

Due to the high optical efficiency of the Liquavista pixel design, Liquavista's displays demonstrate a significant improvement in performance in all lighting environments compared to existing technologies. LCDs, for example, lose more than 50% of the light as a result of the need for polarisation, in addition to significant light losses incurred as a result of attempting to increase effective viewing angles.

Compared to conventional transmissive or emissive displays, Liquavista's reflective displays show vibrant color and have high legibility when placed in direct sunlight.

Liquavista’s electrowetting pixel designs have a naturally broad viewing angle, and do not require any form of polarisation. As a result, even in purely reflective mode, our displays provide excellent performance under almost all usage cases. In high ambient light environments, they perform as vividly as high quality, color paper.

Vibrant Color & Video

Electrowetting displays are all about a revolution in color made possible by their greater optical efficiency than LCD. This greater efficiency can be used to significantly improve brightness and color gamut of reflective, transmissive and transparent displays. In addition, an almost limitless range of color dyes can be added to the oil to make the pixel into a switchable filter enabling a large number of ultra-efficient future display architectures.

As the electrowetting technology is intrinsically fast, it also offers much faster interaction that present-day reflective displays, and has the option to show colorful video content on a paper-like display. In addition, it can also be used in color sequential mode, enabling further value-added architectures that lead to performance improvement and cost reduction.

All Modes of Operation

As the basic optical switch for a display pixel is transmissive, electrowetting displays can be operated in all modes that are currently available in the marketplace: transmissive, transparent and reflective. In fact, electrowetting technology is the only technology that can offer this strong versatility, other than LCD, but with much higher optical efficiency.

This means that electrowetting displays, in principle, provide an alternative to LCD’s in each of the contemporary and future application areas, including wearables, mobile, industrial, automotive and signage.

Power Saving

Power consumption is a hot issue for any mobile application. The same factors that make Liquavista’s displays intrinsically the brightest and most vivid also provide us with a solution to extend battery life in a world where color content, animation and video are core. Because the displays are significantly brighter than existing solutions, Electrowetting displays require less supplementary illumination. For example, in mobile handsets, the backlighting system of a contemporary display may account for as much as 10x the power consumption of the display itself. Reducing the need for additional lighting has a strong positive impact on the overall power budget for the device.