MEMS-related Glossary
Contents:
MEMS Devices
Examples of MEMS devices are below
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[MEMS] Acceleration Sensors  |
Acceleration sensors, as the name implies, detect acceleration, or changes in speed per unit time. These devices have become increasingly compact in recent years, with the application of MEMS technologies. They can be found in a variety of products; for example, automobiles, handheld video games, and smartphones. There are various types of acceleration sensors, but using KRYSTAL Wafer’s PZT in the piezoelectric process contributes to even better performance. Applications E.g.: Automatic driving; airbags |
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[MEMS] Gyro Sensors  |
Gyro sensors detect angular velocity and convert that information into a signal. Those signals are used to detect running paths in car navigation systems, or to correct “camera shake” in digital cameras. MEMS gyro demonstrates outstanding performance in detecting minuscule levels of force. Even stronger signals can be achieved by using materials with high output charge. This further increases accuracy, and enables even more accurate tracing of movement. Applications E.g.: Car navigation systems, camera shake correction, drones, advanced driving support systems, handheld video games, airbags |
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[MEMS] Microphones  |
Contrary to audio output with speakers, piezoelectric materials are also used in microphones as part of audio input devices. When the piezoelectric film receives the sound, the film vibrates, and the vibration is converted into an electrical signal. KRYSTAL Wafer’s piezoelectric film has strong piezoelectric characteristics and low relative dielectric constants, which contribute to a large output charge. This provides an outstanding signal-to-noise (S/N) ratio, and enables detection of even minute sounds. Applications Microphones |
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[MEMS] Speakers  |
Piezoelectric speakers, which use piezoelectric elements, incorporate piezoelectric film in the vibration plate. This vibration plate (the piezoelectric film) converts electrical signals into mechanical vibration, and causes the film to vibrate, which then produces sound. KRYSTAL Wafer’s single crystal PZT film has a high withstand voltage and a high displacement, to generate unprecedented levels of sound pressure. A low dielectric constant also contributes to reduced power consumption. Applications E.g.: Compact speakers; high-performance headphones |
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[MEMS] Pressure Sensors  |
Pressure sensors detect pressure and convert that information into an electrical signal. There are various types of pressure sensors; PZT film is used in piezoresistive (diffusion) pressure sensors, among others. Applications E.g.: Fuel pressure sensors, barometers |
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[MEMS] Ultrasonic Sensors  |
Ultrasonic sensors have two functions: transmission and reception. The ultrasonic wave emitted by the transmitter reflects off of an object, and is detected by the receiver, to determine the object’s presence, as well as its distance. Piezoelectric film is used in both the transmitter and the receiver. By maintaining a low dielectric constant, we achieved higher performance in the receiver’s detection sensitivity, enabling more compact elements with greater sensitivity. Applications E.g.: Automobile parking assist, collision prevention, and “false start” prevention mechanisms, automatic washing and automatic doors, autonomous cleaning robots, drones |
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[MEMS] Ink-Jet Printer Heads  |
Inkjet printer heads use piezoelectric film in the mechanism for discharging ink droplets. These film materials play an extremely important role because the types of ink that can be used, the discharge volumes, and other factors are determined by the characteristics of the piezoelectric film. KRYSTAL Wafer’s PZT actuators feature high displacement volumes and low dielectric constants, which reduce the heat released during operations. This makes it possible to reduce the thermal load on the circuits, and as a result, to increase the number of printer heads that can be installed in a limited space. Applications Inkjet printer heads |
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[MEMS] RF Filters  |
High Radio Frequency (RF) filters are used in telecommunications terminals, operating in a frequency band of 800~2500 MHz. The most common types of RF filters are SAW, BAW, and TC-SAW filters. Piezoelectric film is used in all of these filters. Applications Interdigital Transducers (IDT) |
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[MEMS] Auto Focus  |
Piezoelectric elements are used as actuators incorporated into autofocus mechanisms in the lenses of digital cameras, smartphones, and other optical devices. There are two main types of mechanisms that use these actuators: 1. Mechanisms that move the lens itself, and 2. Mechanisms that adjust the focal length by changing the shape of a fluid In both cases, large displacement volumes are required, but power consumption must also be kept to a minimum. KRYSTAL Wafer's piezoelectric films achieve outstanding performance in both of these conflicting characteristics. Applications Digital cameras, smart phones |
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[MEMS] Mirror  |
Piezoelectric MEMS are used in actuator applications for heads-up displays (HUD), contributing to miniaturization and reduced power consumption. They are also used as mirror actuators in laser projectors. Applications Heads-up Displays (HUD), laser projectors |
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[MEMS] Optical Switches
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Piezoelectric materials including BaTiO₃ crystals and LiNbO₃ crystals are used in optical modulators, applying inverse piezoelectric effects along with electro-optic effects such as the Pockels effect and the Kerr effect. The role of optical switches is to change optical signal routes at relay points in optical communication networks, and piezoelectric materials are used in the actuators that drive the micro-mirrors. Applications Phase modulation elements, optical switches, micro-mirror drive elements |
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[MEMS] Micro-Pumps
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By applying piezoelectric MEMS, PZT film can be used in diaphragm-type micro-pumps. Being compact and lightweight, these pumps are ideal for the continuous transport of minute volumes of liquids. Applications Micro-pumps |
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[MEMS] Flow Sensors
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Among various types of flowmeters, the Karman vortex flowmeter detects “Karman vortex” which arises in putting a pole into streams by using a piezoelectric element. Applications E.g.: Flowmeter |
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[MEMS] Resonators
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Piezoelectric element resonation, commonly referred to as Film Bulk Acoustic Resonator technologies or “FBAR,” is used in the telecommunications field. Applications Resonators |
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[MEMS] Oscillation Power Generation Elements
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Oscillation power generation is a form of energy harvesting technology in which a piezoelectric element is used to generate power from oscillation energy. The Oscillation power generation element can also be used as a power source for the sensor element. Applications Battery-free sensors |
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[MEMS] Smell Sensors
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Piezoelectric film is coated with a sensitive membrane. When odor molecules adhere to this membrane, the sensor detects minuscule changes in the resonance frequency of the piezoelectric film. Because KRYSTAL Wafer’s piezoelectric film demonstrates low loss and high displacement volumes, it becomes possible to better clarify the peaks in resonance frequencies. This enables higher resolution in frequency changes, thereby contributing to better performance in detection sensitivity. Applications Medical breath analyzers, multifunctional environmental measurement devices |
Applications
Examples of applications where MEMS devices are used include below
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LiDAR  |
LiDAR (Light Detection and Ranging) is a technology that uses laser light for detection and distance measurement. It is considered especially important in automatic driving, but has come to be used in a broad range of applications recently, including mobile phones. Applications E.g.: Automatic driving; advanced driving support systems |
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Camera Shake Prevention  |
Piezoelectric materials are used in positional control devices such as camera shake correction mechanisms for digital cameras. Applications Digital cameras |
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Infrared Camera  |
Pyroelectric infrared sensors use the effects of pyroelectric ceramics to detect infrared light. The spontaneous polarization of the piezoelectric material causes a temperature change when the infrared light is received, and an electric charge proportionate to the pyroelectric coefficient is generated in the optic receiver. This charge is immediately neutralized, but the sensor detects the voltage that is generated instantaneously at that moment. Applications E.g.: Motion sensors, air conditioners |
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Local Vacuum
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A technology called “local vacuum” has gained attention as a near-future technology that could become a reality through the use of KRYSTAL Wafer’s PZT film. For example, a micro-pump driven by the piezoelectric properties of PZT film can be used to generate a low-level vacuum. This micro-pump could then be attached to the end of a robot arm, allowing the robot arm to hold onto an object. Using this PZT film simplifies the design dramatically, because only a power cable is required to drive the unit. Applications Industrial robot arms |
