A MEMS (Micro-Electro-Mechanical System) energy-efficient micromirror is a fundamental component used in various display technologies, such as DLP (Digital Light Processing) projectors and other microdisplay applications. This micromirror operates on the principle of electrostatic attraction and repulsion to efficiently control the reflection of light, enabling the creation of images and videos on a display.
Here's how a MEMS energy-efficient micromirror typically operates:
Mirror Structure: The micromirror is fabricated using microfabrication techniques on a silicon substrate. It consists of a tiny reflective mirror plate suspended by torsion springs. This mirror plate is typically made of a highly reflective material, such as aluminum or gold, to ensure efficient light reflection.
Actuation Mechanism: Beneath the mirror plate, there are one or more pairs of electrodes. These electrodes are part of the electrostatic actuation mechanism. By applying a voltage difference between the electrodes, an electrostatic force is generated. This force can either attract or repel the mirror plate, causing it to tilt.
Tilt Operation: The mirror plate can tilt in two main states: "on" and "off" positions. In the "on" state, the mirror plate is tilted towards the substrate, reflecting incident light away from the display optics. In the "off" state, the mirror plate is flat or tilted in the opposite direction, allowing light to be directed towards the display optics. The tilting action is controlled by adjusting the voltage applied to the electrodes.
Pixel Array: In a display application, numerous MEMS micromirrors are arranged in a pixel array. Each micromirror corresponds to a single pixel on the display. By controlling the voltage applied to each micromirror's electrodes, the individual micromirrors can be tilted to direct light either towards or away from the projection optics.
Color and Brightness Control: To achieve color and brightness control, the light source can be filtered through a color wheel or modulated using a light source, such as LEDs. By selectively activating micromirrors in specific pixels, different colors can be displayed. Varying the duration and intensity of the micromirror's "on" state also allows control over pixel brightness.
Energy Efficiency: The key advantage of MEMS micromirrors is their energy efficiency. They require very little power to move, as the electrostatic forces used for actuation consume minimal energy. Additionally, once a micromirror is tilted to a specific angle, it requires no continuous power to maintain that position.
Applications: MEMS micromirrors find applications in various display technologies, including digital projectors, heads-up displays, and augmented reality devices. Their energy efficiency, small form factor, and fast response time make them well-suited for portable and power-constrained devices.
In summary, a MEMS energy-efficient micromirror operates by utilizing electrostatic forces to control the tilting of a reflective mirror plate. This tilting action enables the redirection of light for display purposes, offering advantages such as energy efficiency, fast response times, and the ability to create high-quality images and videos in various display applications.