Micro-piezoelectric driver for MEMS

Abstract

The miniature piezoelectric driver capable of producing deflection angle and vertical displacement for MEMS is characterized by that its structure is a kind of suspension folded piezoelectric composite multi-layer film elastic driving arm, it has at least two sections or more than two sections of parallel driving arms. The driving arms of two sides of suspension structure are connected with substrate. Every driving arm contains elastic layer and piezoelectric composite film on the elastic layer. When the driving voltages with opposite polarity are applied on the upper and lower electrodes of piezoelectric films on the adjacent parallel different driving arms, the parallel adjacent piezoelectric driving arms can produce opposite bend, and on the driving arm of middle portion positioned in the suspension structure the maximum vertical displacement or deflection angle can be produced.

Description

technical field [0001] The invention belongs to the field of micro-electronic machinery, in particular to a micro piezoelectric driver for MEMS. Background technique [0002] Micro Electro Mechanical System (MicroElectroMachanical System), referred to as MEMS. It is the cutting-edge science in high-tech fields such as miniaturization, integration, intelligence, informatization, and advanced manufacturing. MEMS is based on advanced semiconductor technology and integrated circuit manufacturing technology, which broadens the method of manufacturing complex electromechanical systems on microchips. These methods combine the large-scale integrated circuit manufacturing technology and the unique special process of micromachining technology, and integrate micromechanical structures, microactuators, microelectronic devices and circuit systems to form a so-called system on chip (SOC). The entire MEMS involves many disciplines from design to manufacture, as well as computer technolog...

AI Technical Summary

Problems solved by technology

Most of the existing micro-execution structures using these principles have a large driver size and occupy a large chip area, but the realized driving displacement and deflection are limited, the manufacturing process is complicated, the reliability is not high, the power consumption is large, and the life is short

Most of the MEMS piezoelectric film drive methods that have been widely studied use a cantilever beam structure. Due to the limited elongation of the piezoelectric film, the maximum deflection displacement on the cantilever beam structure is very limited. This characteristic limits the piezoelectric drive method. The wide application in the field of MEMS has resulted in the emergence of very few mature MEMS commercial devices driven by piezoelectric films.

To achieve large vertical displacement or deflection of this kind of cantilever driving structure, it is required to lengthen the length of the beam and increase the driving voltage, which increases the static deflection of the cantilever beam caused by gravity on the one hand, so that when no voltage is applied, the cantilever will have Large deflection displacement, which seriously limits its application range

On the other hand, this long straight cantilever beam drive structure significantly reduces the mechanical strength of the drive, and it is prone to vibration during work, and it is very easy to be broken by impact.

In addition, this long single cantilever drive structure increases the inertial influence of the cantilever itself, which reduces the operating frequency of the drive and is not suitable for many applications with high operating frequency

At the same time, a large driving voltage can easily cause the piezoelectric film to break down, which puts higher requirements on the quality of the piezoelectric film and increases the difficulty of the piezoelectric film deposition process.

Brings many additional effects to the piezoelectric film and increases the complexity of the corresponding electronic circuit

And in terms of manufacturing, the complexity of manufacturing is significantly increased, the yield of micromachining is reduced, and the length of the driver is too long, which also makes it difficult to adapt to the application in some microstructure devices or device arrays

These have severely limited the application of cantilever piezoelectric actuators in microelectromechanical devices and systems

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