CN108163804A - It is a kind of can dynamic driving MEMS micro-structures four-axle type exciting bank - Google Patents

Abstract

The invention discloses a four-axis excitation device capable of dynamically driving a MEMS microstructure, which includes a sleeve and a bottom plate, piezoelectric ceramics, a pressure sensor, upper and lower connecting blocks, elastic supports and a MEMS microstructure; There is a ring-shaped top plate, and the microstructure is set on the ring-shaped top plate through elastic supports; guide shafts are evenly distributed between the ring-shaped top plate and the bottom plate, and the lower connecting block is evenly distributed with guide arms, which are passed through the sleeve wall and sleeved on the guide shaft Above: there is a spherical protrusion at the center of the bottom surface of the upper coupling block, and tension springs are evenly distributed on the circumference between the bottom surface of the upper coupling block and the guide arm of the lower coupling block, and the spherical protrusion is elastically pressed against the lower coupling block by the tension spring; The piezoelectric ceramic is sandwiched between the pressure sensor and the elastic support. The device can apply different sizes of pre-tightening force to the piezoelectric ceramics, so that the obtained pre-tightening force measurement value is more accurate, and the adjustment process of compensating the parallelism error of the two working surfaces of the piezoelectric ceramics becomes smoother and smoother, which is convenient Test dynamic characteristic parameters.

Description

A four-axis excitation device that can dynamically drive MEMS microstructures

technical field

The invention belongs to the technical field of micromechanical electronic systems, in particular to a four-axis excitation device capable of dynamically driving MEMS microstructures.

Background technique

Due to the advantages of low cost, small size and light weight, MEMS microdevices have broad application prospects in many fields such as automobile, aerospace, information communication, biochemistry, medical treatment, automatic control and national defense. For many MEMS devices, the micro-displacement and micro-deformation of their internal microstructures are the basis for the realization of device functions. Therefore, accurate testing of dynamic characteristic parameters such as the amplitude, natural frequency, and damping ratio of these microstructures has become the key to developing MEMS products. important content.

In order to test the dynamic characteristic parameters of the microstructure, it is first necessary to make the microstructure vibrate, that is, to excite the microstructure. Due to the small size, light weight and high natural frequency of MEMS microstructures, the excitation methods and excitation devices in traditional mechanical mode testing cannot be applied to the vibration excitation of MEMS microstructures. In the past thirty years, researchers at home and abroad have conducted a lot of explorations on the vibration excitation methods of MEMS microstructures, and have developed some excitation methods and corresponding excitation devices that can be used for MEMS microstructures. Among them, the base excitation device using stacked piezoelectric ceramics as the excitation source has the advantages of large excitation bandwidth, simple device, easy operation, and strong applicability, so it has been widely used in the field of MEMS microstructure dynamic characteristic testing. In the article "A base excitation test facility fordynamic testing of microsystems", David et al. introduced a base excitation device based on piezoelectric ceramics. In this device, stacked piezoelectric ceramics are directly bonded on a fixed base. The stacked piezoelectric ceramics is a multi-layer bonding structure, so the stacked piezoelectric ceramics can withstand a large pressure, but it cannot bear the tensile force. The tensile force will cause the damage of the stacked piezoelectric ceramics. When the stacked piezoelectric ceramics are in When in use, applying a certain pre-tightening force is beneficial to prolong the service life of stacked piezoelectric ceramics, but this device does not consider the above problems; Wang et al. in the article "Dynamic characteristic testing forMEMS micro-devices with base excitation" This paper introduces a base excitation device based on piezoelectric ceramics. In this device, the problem of applying a certain pre-tightening force to the stacked piezoelectric ceramics is considered. Electric ceramics, and the size of the pre-tightening force can be changed by turning the adjusting screw, but this device does not take into account that when the above-mentioned mechanism is used to apply the pre-tightening force to the stacked piezoelectric ceramics, due to the two working surfaces of the stacked piezoelectric ceramics The parallelism error will generate a shear force between the layers of the stacked piezoelectric ceramics, which will cause mechanical damage to the stacked piezoelectric ceramics. In addition, the device cannot measure the applied preload. If the size is not adjusted properly, it will also cause mechanical damage to the stacked piezoelectric ceramics.

The Chinese invention patent with the publication number CN101476970A discloses a base excitation device based on piezoelectric ceramics. In this device, a cross spring plate is used to apply a preload to the stacked piezoelectric ceramics, and the bottom of the stacked piezoelectric ceramics is installed On a movable base structure to reduce the shear force on the piezoelectric ceramics, in addition, a pressure sensor is also provided in the device to detect the pre-tightening force applied to the piezoelectric ceramics and stack piezoelectric ceramics output force at work. But this device still has following shortcoming:

1. The movable base structure of the device is composed of an upper connection block, a steel ball and a lower connection block. The steel ball, the upper connection block and the lower connection block are in line contact. When it is necessary to compensate the top surface of the stacked piezoelectric ceramics and the When the movable base structure is adjusted by itself due to the parallelism error of the two working surfaces on the bottom surface, the steel ball cannot rotate smoothly, and may even be stuck;

2. There is no direct connection between the upper connection block and the lower connection block and the sleeve, but are installed in the sleeve in turn by means of clearance fit. If the parallelism error of the two working surfaces of the stacked piezoelectric ceramics is large , there is not enough space to adjust the movable base structure;

3. The pressure sensor is installed at the bottom of the lower connecting block. Since the movable base structure is self-adjusted, there is a certain inclination between the bottom of the lower connecting block and the working surface of the piezoelectric ceramic, so the pre-tightening force measured by the pressure sensor Or the output force of piezoelectric ceramics is not accurate; in addition, if the movable base structure causes the upper coupling block or the lower coupling block to contact the sleeve after adjustment, the error of the measurement result will further increase;

4. In the device, one side of the cross spring is used to compress the stacked piezoelectric ceramics, and the other side of the cross spring is bonded to the micro device for testing. When the piezoelectric ceramics are working, the deformation of the cross spring is relatively large. Cause the colloid between the micro-device and the cross spring to crack, causing the micro-device to fall off;

5. In this device, gaskets of different thicknesses are used to change the magnitude of the pre-tightening force applied to the stacked piezoelectric ceramics, resulting in a complicated adjustment process and insufficient flexibility.

Contents of the invention

The technical problem to be solved by the present invention is to provide a four-axis excitation device that can dynamically drive MEMS microstructures. The measured value of the tightening force is more accurate, which can make the adjustment process of compensating the parallelism error of the two working surfaces of the stacked piezoelectric ceramics smoother and smoother, greatly reducing the shear force between the layers of the stacked piezoelectric ceramics, and being able to It can provide a larger adjustment space, avoid the falling off of the micro-device used for testing, and facilitate the testing of the dynamic characteristic parameters of the MEMS microstructure.

In order to solve the above problems, the present invention adopts the following technical solutions:

A four-axis excitation device that can dynamically drive MEMS microstructures, including a sleeve and a bottom plate, in which a stack of piezoelectric ceramics, a pressure sensor, an upper coupling block and a lower coupling block are arranged, and on the sleeve is a Elastic support and MEMS microstructure characterized by:

An annular top plate is provided at the upper end of the sleeve, and the MEMS microstructure is installed on the annular top plate through an elastic support; the elastic support includes a base plate and four support arms uniformly distributed around the circumference, and each support arm is connected to each other in sequence. The first connecting arm, the second connecting arm, the third connecting arm and the fourth connecting arm are vertically connected to reduce the deformation of the substrate;

Between the annular top plate and the bottom plate, guide shafts are evenly distributed on the outer circumference of the sleeve, and U-shaped notches corresponding to the guide shafts are evenly distributed on the sleeve wall along the circumferential direction, and the outer edge of the lower coupling block is uniformly distributed There are guide arms and each guide arm passes through the corresponding U-shaped notch and is fitted on the guide shaft;

A spherical protrusion is arranged at the center of the bottom surface of the upper coupling block, and a tension spring is evenly distributed on the circumference between the bottom surface of the upper coupling block and the guide arm of the lower coupling block, and the spherical protrusion is elastically pressed against the bottom coupling block by the tension spring. The center of the top surface; to form a point contact between the upper and lower connecting blocks, which is used to assist the upper connecting block to compensate for the adjustment of the parallelism error of the two working surfaces of the stacked piezoelectric ceramics;

The pressure sensor is embedded in the center hole on the top surface of the upper connection block, and the stacked piezoelectric ceramics are clamped between the pressure sensor and the elastic support;

A supporting plate is arranged at the lower part of the sleeve, and an electric screw drive mechanism is installed vertically in the center of the support plate. The screw nut of the electric screw drive mechanism is connected with the lower connecting block for driving the lower connecting block to move up and down.

As a further preference, the substrate is square, and the four support arms are respectively connected to one end around the substrate through the first connecting arm and form an L-shaped gap with the outer edge of the substrate; to further reduce the deformation of the substrate and avoid MEMS microstructures Shedding occurs due to colloidal cracking.

As a further preference, the outer ends of the four support arms of the elastic support are respectively supported and fixed on the annular top plate through pillars.

As a further preference, there are four guide shafts.

As a further preference, a mounting sleeve is fastened on the upper end of the stacked piezoelectric ceramics, and the elastic support is pressed on the mounting sleeve to avoid the stacked piezoelectric ceramics caused by the roughness of the top working surface of the stacked piezoelectric ceramics. Poor contact between ceramic and elastic supports.

As a further preference, each guide arm is respectively provided with a through hole for penetrating the guide shaft, and a shaft sleeve is respectively embedded in the through hole.

As a further preference, on the bottom surface of the upper coupling block and on the guide arms of the lower coupling block, there are respectively evenly distributed up and down corresponding spring mounting seats along the circumferential direction, and the two ends of the tension spring are respectively connected to two springs corresponding up and down. on the mount.

The beneficial effects of the present invention are:

1. Since there is a spherical protrusion at the center of the bottom surface of the upper coupling block, the spherical protrusion is elastically pressed against the center of the top surface of the lower coupling block through the tension springs evenly distributed around the circumference, so that a point contact is formed between the upper and lower coupling blocks; when required When adjusting the movable base by compensating for the parallelism error of the two working surfaces of the stacked piezoelectric ceramics, the upper connecting block will rotate with the contact point with the lower connecting block as the center of rotation, and the adjustment process is smooth and smooth without jamming problem, greatly reducing the shear force between the layers of the stacked piezoelectric ceramics.

2. Since there are extension springs evenly distributed on the circumference between the bottom surface of the upper connection block and the guide arm of the lower connection block, the upper connection block is elastically pressed on the lower connection block by the tension spring; when it is necessary to compensate the stacked piezoelectric ceramics When the parallelism error of the two working surfaces is used to adjust the movable base, the swing of the upper connecting block in different directions can be realized through the deformation of the tension spring, and the adjustable space is larger.

3. Since the pressure sensor is embedded in the center hole on the top surface of the upper connecting block, the stacked piezoelectric ceramics are clamped between the pressure sensor and the elastic support, so when the pre-tightening force is applied to the stacked piezoelectric ceramics , which avoids the interference of the movable base structure on the pressure sensor, and can obtain more accurate pre-tightening force data; when the stacked piezoelectric ceramics work, the measured value of the excitation force obtained is also more accurate.

4. Since the electric screw drive mechanism is installed vertically in the center of the support plate, the screw nut of the electric screw drive mechanism is connected to the lower connecting block. When it is necessary to apply different sizes of pretightening force to the stacked piezoelectric ceramics It can be realized by driving the movable base composed of the upper coupling block and the lower coupling block to move through the electric screw transmission mechanism, and the adjustment process is simple and flexible.

5. Since the elastic support includes a base plate and four support arms uniformly distributed around the circumference, each support arm is composed of a first connecting arm, a second connecting arm, a third connecting arm and a fourth connecting arm which are vertically connected to each other in sequence , when the stacked piezoelectric ceramics work, the vibration deformation of the elastic support mainly comes from the four support arms, while the deformation of the substrate is very small, so the colloid will not crack and the micro devices will not fall off.

Description of drawings

Fig. 1 is a schematic diagram of the three-dimensional structure of the present invention.

Figure 2 is a top view of the present invention.

Fig. 3 is a cross-sectional view along line A-A of Fig. 2 .

Fig. 4 is a top view of the elastic support.

Fig. 5 is a schematic perspective view of the lower connection block.

Fig. 6 is a schematic perspective view of the three-dimensional structure of the sleeve.

In the figure: 1. Sleeve, 101. U-shaped notch, 2. Annular top plate, 3. Bottom plate, 4. MEMS microstructure, 5. Microstructure mounting plate, 6. Elastic support, 601. Support arm, 6011. No. One connecting arm, 6012. Second connecting arm, 6013. Third connecting arm, 6014. Fourth connecting arm, 602. Base plate, 7. Pillar, 8. Mounting sleeve, 9. Spring mount, 10. Stacked piezoelectric Ceramics, 11. Pressure sensor, 12. Extension spring, 13. Upper connection block, 1301. Spherical protrusion, 14. Bushing, 15. Lower connection block, 1501. Guide arm, 16. Screw nut, 17. Support plate , 18. Linear stepping motor, 19. Guide shaft, 20. Lead screw.

Detailed ways

As shown in Figures 1 to 6, a four-axis excitation device that can dynamically drive MEMS microstructures involved in the present invention includes a hollow sleeve 1, in which stacked piezoelectric ceramics 10, pressure The sensor 11 and the movable base composed of the upper coupling block 13 and the lower coupling block 15 are provided with an elastic support 6 and a MEMS microstructure 4 on the sleeve 1 .

An annular top plate 2 and a bottom plate 3 with equal outer diameters are respectively fixed on the upper surface and the bottom surface of the sleeve 1 by screws, and the MEMS microstructure 4 is mounted on the annular top plate 2 through an elastic support 6 . The elastic support includes a square base plate 602 and four support arms 601 uniformly distributed around the circumference, each support arm 601 is composed of a first connecting arm 6011, a second connecting arm 6012, and a third connecting arm 6013 which are vertically connected in sequence. Composed of the fourth connecting arm 6014, the four supporting arms 601 are respectively connected to one end of the peripheral end surface of the substrate 602 through the first connecting arm 6011, and an L-shaped gap is formed between the second connecting arm 6012 and the third connecting arm 6013 and the outer edge of the substrate 602 ; It is used to reduce the deformation of the substrate and prevent the MEMS microstructure 4 from falling off due to cracking of the colloid. The outer ends of the four support arms 601 of the elastic support member 6 are respectively supported and fixed on the annular top plate 2 through the hollow pillar 7 with screws, and are on the same axis as the sleeve 1 . The MEMS microstructure 4 is fixed on the center of the upper surface of the substrate 602 of the elastic support 6 through the microstructure mounting plate 5 .

The pressure sensor 11 is embedded and bonded in the center hole of the top surface of the upper connecting block 13, the stacked piezoelectric ceramic 10 is cylindrical and the lower end is bonded to the pressure sensor 11, and the two ends of the stacked piezoelectric ceramic 10 are clamped held between the pressure sensor 11 and the base plate 602 of the elastic support 6 . A mounting sleeve 8 is fastened and bonded to the upper end of the stacked piezoelectric ceramics 10, and the base plate 602 of the elastic support 6 is pressed on the mounting sleeve 8 to avoid the roughness of the top working surface of the stacked piezoelectric ceramics 10. The resulting problem of poor contact between the stacked piezoelectric ceramics 10 and the elastic support member 6 .

Between the annular top plate 2 and the bottom plate 3, there are four guide shafts 19 evenly distributed on the outside of the sleeve 1 through screws, and four U-shaped notches corresponding to the guide shafts are uniformly distributed along the circumference of the sleeve wall. 101. The lower coupling block 15 is cylindrical, and there are four guide arms 1501 evenly distributed on the lower end circumference of the outer edge of the lower coupling block 15, and each guide arm 1501 passes through the corresponding U-shaped notch 101 and is sleeved on it by a clearance fit. On the guide shaft 19, each guide arm 1501 is provided with a through hole passing through the guide shaft and a shaft sleeve 14 is respectively embedded in the through hole, and the lower coupling block 15 can be guided by the guide shaft 19. Slide up and down inside the sleeve 1 in the vertical direction.

A spherical protrusion 1301 is arranged at the center of the bottom surface of the upper coupling block 13, and extension springs 12 are evenly distributed on the circumference between the bottom surface of the upper coupling block 13 and the guide arm 1501 of the lower coupling block 15, and the spherical protrusion 1301 passes through the extension spring. 12 is elastically pressed on the center of the top surface of the lower connecting block 15; so that a point contact is formed between the upper and lower connecting blocks. 13 will rotate with the contact point with the lower coupling block 15 as the center of rotation, the adjustment process is smooth and smooth, and the problem of jamming will not occur, which greatly reduces the shear force between the layers of the stacked piezoelectric ceramics.

On the bottom surface of the upper coupling block 13 and the guide support arm 1501 of the lower coupling block 15, there are spring mounting seats 9 corresponding to the upper and lower ones respectively distributed along the circumferential direction by screws, and the two ends of the extension spring 12 are respectively connected to two upper and lower mutual On the corresponding spring mounting seat 9.

A support plate 17 is fixed by screws at the bottom step of the sleeve 1, and an electric screw drive mechanism is installed in the center of the support plate 17 along the vertical direction. The screw 20 of the output shaft of the stepping motor 18 and the screw nut 16 are composed of the linear stepping motor 18 installed on the bottom surface of the support plate 17, the upper end of the screw 20 is inserted into the center hole of the bottom surface of the lower connecting block 15, and the screw nut 16 is connected with the lower The blocks 15 are connected by screws uniformly distributed on the circumference, and are used to drive the lower connecting block 15 to move up and down.

When working, firstly control the linear stepping motor 18 to push up the movable base composed of the upper coupling block 13 and the lower coupling block 15 through the transmission of the lead screw 20 and the nut 16 to apply a pre-tightening force to the stacked piezoelectric ceramics 10, and at the same time The pre-tightening force data measured by the pressure sensor 11 is monitored, and when the pre-tightening force reaches a set value, the linear stepper motor 18 is controlled to stop working. Then, an external power supply is used to apply a pulse signal or a frequency sweep signal between the two electrodes of the stacked piezoelectric ceramics 10, and the inverse piezoelectric effect of the stacked piezoelectric ceramics 10 is used to excite the MEMS microstructure 4. The contact vibration measuring device detects the vibration response of the MEMS microstructure 4 , and the pressure sensor 11 is used to detect the output force of the stacked piezoelectric ceramics 10 . Finally, after the excitation of the MEMS microstructure 4 is completed, the linear stepper motor 18 is controlled to drive the movable base structure composed of the lower coupling block 15 and the upper coupling block 13 to move downward, so that the top mounting sleeve 8 of the stacked piezoelectric ceramics 10 It is separated from the elastic support member 6 to prevent the stacked piezoelectric ceramics 10 from being under stress all the time.

Although the embodiment of the present invention has been disclosed as above, it is not limited to the use listed in the specification and implementation, it can be applied to various fields suitable for the present invention, and it can be easily understood by those skilled in the art Therefore, the invention is not limited to the specific details and examples shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims (7)

1. it is a kind of can dynamic driving MEMS micro-structures four-axle type exciting bank, including sleeve and bottom plate, be equipped in sleeve folded Heap piezoelectric ceramics, pressure sensor, upper coupling block and lower connection block are equipped with elastic supporting member for supporting optical member and the micro- knots of MEMS on sleeve Structure, it is characterized in that：

Annular roof plate is equipped in sleeve upper end, the MEMS micro-structures are mounted on by elastic supporting member for supporting optical member on annular roof plate；It is described Elastic supporting member for supporting optical member includes the support arm of one piece of substrate and four circumference uniform distributions, and each support arm by being mutually connected vertically successively First linking arm, the second linking arm, third linking arm and the 4th linking arm composition, for reducing the deflection of substrate；

It is located between annular roof plate and bottom plate outside sleeve and is evenly distributed in guiding axis, it is along the circumferential direction uniformly distributed in sleeve wall Have with guiding axis U-shaped gap correspondingly, the lower connection block outer marginal circumference, which is evenly equipped with, to be oriented to support arm and is each oriented to support arm It is passed through and is sleeved on guiding axis by corresponding U-shaped gap respectively；

Spherical surface hill, the circumference between upper coupling block bottom surface and the guiding support arm of lower connection block are equipped in upper coupling block bottom center Uniformly be connected with tension spring, the spherical surface hill by tension spring elastic compression lower connection block end face center；Make upper and lower coupling block Between form point contact, for upper connection block compensation to be assisted to stack the adjusting of two working surface parallelism error of piezoelectric ceramics；

The pressure sensor is installed in the centre bore of coupling block top surface, stack piezoelectric ceramics be clamped in pressure sensor with Between elastic supporting member for supporting optical member；

Lower part is equipped with support plate in sleeve, and electric threaded shaft transmission mechanism is vertically equipped at support plate center, electronic The screw of lead-screw drive mechanism is connect with lower connection block, for lower connection block to be driven to move up and down.

2. it is according to claim 1 it is a kind of can dynamic driving MEMS micro-structures four-axle type exciting bank, it is characterized in that：Institute State substrate for square, four support arms respectively by the first linking arm be connected to substrate surrounding one end and with substrate outer edge shape Into a L-type gap；Further to reduce the deflection of substrate, MEMS micro-structures is avoided to be fallen off due to colloid cracks.

3. it is according to claim 2 it is a kind of can dynamic driving MEMS micro-structures four-axle type exciting bank, it is characterized in that：Institute Four support arm outer ends for stating elastic supporting member for supporting optical member are supported and fixed on by pillar above annular roof plate respectively.

4. it is according to claim 1 it is a kind of can dynamic driving MEMS micro-structures four-axle type exciting bank, it is characterized in that：Institute It is four to state guiding axis.

5. according to claims 1 or 2 or 3 it is a kind of can dynamic driving MEMS micro-structures four-axle type exciting bank, it is special Sign is：Installation set is equipped with stacking piezoelectric ceramics upper end button, the elastic supporting member for supporting optical member is pressed in installation set, for avoiding due to folded Heap piezoelectric ceramics top work surface it is rough caused by stack asking for piezoelectric ceramics and elastic supporting member for supporting optical member loose contact Topic.

6. it is according to claim 1 it is a kind of can dynamic driving MEMS micro-structures four-axle type exciting bank, it is characterized in that： Each be oriented to is respectively provided with the through-hole through guiding axis on support arm and is installed with axle sleeve respectively in through-hole.

7. it is according to claim 1 it is a kind of can dynamic driving MEMS micro-structures four-axle type exciting bank, it is characterized in that： One-to-one spring installation up and down is along the circumferential direction evenly equipped on the guiding support arm of upper coupling block bottom surface and lower connection block respectively Seat, the tension spring both ends are connected on about two mutual corresponding spring mounting seats.