Benefits of mirasol Display Technology

Micro-electro-mechanical Systems (MEMS) Drive IMOD Reflective Technology

The core building blocks of mirasol displays, the Interferometric Modulator (IMOD) element is a simple MEMS (micro-electro-mechanical system) device.

The IMOD element has two stable states. When no voltage is applied, the plates are separated, and light hitting the substrate is reflected. When a small voltage is applied, the plates are pulled together by electrostatic attraction and the light is absorbed, turning the element black.

This is the fundamental building block from which Qualcomm's mirasol displays are made and produce color.

Exceptional Sunlight Readability

How Color Is Created

At the most basic level, a mirasol display is an optically resonant cavity. The device consists of a self-supporting deformable reflective membrane and a thin-film stack (each of which acts as one mirror of an optically resonant cavity), both residing on a transparent substrate.

When ambient light hits the structure, it is reflected both off the top of the thin-film stack and off the reflective membrane. Depending on the height of the optical cavity, light of certain wavelengths reflecting off the membrane will be slightly out of phase with the light reflecting off the thin-film structure. Based on the phase difference, some wavelengths will constructively interfere, while others will destructively interfere.

The human eye will perceive a color as certain wavelengths will be amplified with respect to others. The image on a mirasol display can switch between the selected color and black by changing the membrane state. This is accomplished by applying a voltage to the thin-film stack, which is electrically conducting and is protected by an insulating layer. When a voltage is applied, electrostatic forces cause the membrane to collapse.

The change in the optical cavity now results in constructive interference at ultraviolet wavelengths, which are not visible to the human eye. Hence, the image on the screen appears black.

A full-color display is assembled by spatially ordering IMOD elements reflecting in the red, green and blue wavelengths.

Overview of mirasol Display Benefits

Qualcomm’s mirasol displays are a technology breakthrough that deliver substantial performance benefits over competing display technologies. Never before has a single display technology supported color and interactive content while also offering crisp visibility inside and outdoors with energy efficiency to provide weeks of battery life.

Crisp Content Even in Bright Sunlight

As a color reflective display, mirasol is illuminated by the ambient conditions where it is used. This means that even in the brightest conditions, a mirasol display will remain crisp and clear to view. For instances where no ambient light exists, Qualcomm has developed an integrated reading light to illuminate the display.

Energy Efficient for Long Battery Life

Qualcomm’s mirasol displays use microscopic mirrors to reflect ambient light. This means mirasol displays do not use a backlight,one of the largest consumers of power in today's backlit displays.

mirasol displays are also bi-stable, which allows for near-zero power usage in situations where the display image is unchanged. This means that mirasol displays benefit from considerable power savings, especially compared to displays that continually refresh, such as LCDs. Read more about bi-stability in the Technology Overview whitepaper.

Rapid Refresh Rate Supports Video

Unlike other commercialized e-reader displays, mirasol displays are able to meet modern desires of dynamic, interactive content, as well as
the sensibilities for a more traditional reading experience.

Since visible light wavelengths operate on the nanometer scale (i.e., 380nm
to 780nm), the deformable IMOD membrane only has to move a short distance
— a few hundred nanometers—in order to switch between on (reflecting color)
or off (black). This switching happens extremely fast, on the order of tens of
microseconds. This switching speed directly translates to a video rate-capable
display.

Naturally Brilliant Color Inspired By Nature

mirasol displays’ nature-inspired method of creating color is nothing short of
genius. Put simply, the display generates color by mimicking the processes
observed in butterfly wings or peacock feathers. It’s a natural palette: iridescent,
shimmering and brilliant.

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