Showing papers on "Bimorph published in 1993"

Fabrication and operation of polyimide bimorph actuators for a ciliary motion system

Abstract: In order to extract macroscopic mechanical work out of microelectromechanical systems, we have proposed the concept of distributed micromotion systems (DMMS). The key idea of DMMS is to coordinate simple motions of many microactuators in order to perform a task. Design, fabrication, and operation of a type of DMMS, called a ciliary motion system, are presented. A bimorph thermal actuator using two types of polyimides with different thermal expansion coefficients and a metallic microheater in between them was fabricated. The cantilever-shaped actuator curled up from the substrate owing to the residual stress in polyimides which built up during the cooling process after they were cured at 350 degrees C. It flattened and moved downward by flowing current in the heater. The dimensions of the cantilever were 500 mu m in length, 100 mu m in width, and 6 mu m in thickness. The tip of the cantilever moved 150 mu m in the direction vertical to the substrate and 80 mu m in the horizontal direction; these were the maximum displacements obtained with 33 mW dissipated in the heater. The cut-off frequency was 10 Hz. On a 1-cm-square substrate, 512 cantilevers were fabricated to form an array. Two sets of cantilevers were placed opposing to each other. We operated them in coordination to mimic the motion and function of cilia and carried a small piece of a silicon wafer (2.4 mg) at 27-500 mu m/s with 4-mW input power to each actuator. >

Analysis of distributed thermopiezoelectric sensors and actuators inadvanced intelligent structures

Abstract: The quasistatic equations of piezoelectricity and thermopiezoelectricity are used to develop a finite element formulation of distributed piezoelectric and thermopiezoelectric media. The formulation is then integrated with the distributed sensing and control of advanced intelligent structure design. The procedure is illustrated with the help of two example problems. The purpose of the first example, which consists of two piezoelectric layers used as a bimorph robotic finger, is to check the accuracy of the finite element solution with the analytical one. As a second example, an aluminum beam is utilized along with two polyvinylidene fluoride layers acting as distributed actuator and sensor to study the distributed control of the beam when thermal effects are present. It is concluded that the thermal effects are important in the precision distributed control of intelligent structures.

Flextensional "moonie" actuators

Abstract: In recent years, piezoelectric and electrostrictive ceramics have been used in many actuators applications. A new type of composite actuator, which is based on the concept of a flextensional transducer, has been developed. (1-6) This ceramicmetal composite actuator, or "moonie" consists of either a piezoelectric ceramic disk or a multilayer stack sandwich between two specially designed metal end caps. This new design provides a sizeable displacement, as well as a large generative force. In other words, it bridges the gap between the two most common types of actuator; the multilayer and bimorph (7).

Characteristics of optical actuator-servomechanisms using bimorph optical piezo-electric actuator

Abstract: A bimorph type of the optical piezoelectric actuator (PLZT) which has relatively large displacement is discussed. This optical actuator works under the on-off control of the UV beam irradiation. The response characteristics of the actuator for the UV beam irradiation is shown. The response time of this actuator is improved compared with the previous one. An optical actuator-servosystem is proposed. Based on the mathematical model of the optical actuator, the transfer function of the optical servo control system is identified, and experiments are conducted. The experimental results agree with simulation results based on the mathematical model. Two application examples of this actuator are given. One is an optical gripper, while the other is an optical mobile robot. >

Piezoelectric head actuator

Abstract: A bimorph element is formed by bonding first and second piezoelectric bodies together with an elastic shim interposed between. The bimorph element is firmly held by a base frame which has a recess and a groove at the bottom of the recess. The elastic shim 103 has an extending portion which is firmly inserted in the groove and its end portion is inserted in the recess of the base frame. A space between the recess and the end portion of the bimorph element is filled by an elastic support member.

Modeling of the electromechanical performance of piezoelectric laminated microactuators

Abstract: Piezoelectric microactuators may be considered as multilayer laminated composites consisting of alternating layers of piezoelectric and non-piezoelectric materials A generalized analytical formulation of mechanical deformations as a function of applied electric field is derived for an arbitrary lay-up of such laminates Based on the generalized theory developed, specific formulae for the electromechanical performance of two cantilever microactuator lay-up geometries including a single piezo/elastic laminate and a bimorph, are derived In the modeling of the electromechanical performance of piezoelectric microactuators, the present model incorporates both d211 and d222 Furthermore, the elastic properties of both the piezoelectric and the elastic materials have been considered The developed model is evaluated based on a comparison with results from experiment

Compressed gas container with shape memory alloy pressure relief member

Abstract: A container (10) for compressed gas with a pressure relief member (18) made from a bimorph shape memory material. The bimorph (18) is impermeable by the gas. The bimorph (18) assumes a shape which changes depending on temperature. Below a critical temperature, the bimorph (18) lies in a first (deformed) state, and reverts to a second (remembered) state thereabove. The gas is entrapped within the container (10) when the bimorph (18) assumes the first state. When pressure rises due to temperature increase above the critical temperature, gas may escape from the container (10). This is because the bimorph (18) reverts to its second state, in which a relief gas passageway is opened, thereby relieving gas pressure.

Magneto-optical recording/reproducing system having an electromagnetic actuator

Abstract: Magneto-optical disk recording and reproducing devices and actuators and distance detectors for use therewith are disclosed. The mageneto-optical disk device comprises, in addition to the usual elements, a bimorph type actuator or an electromagnetic actuator for driving the magnetic head of the magneto-optical disk device. The bimorph actuator has a metallic shim whose width varies with respect to the longitudinal distance inversely porportional to the normal function of the first or the second free natural vibration mode. Alternatively, the bimorph type actuator have a recess formed on a bimorph element to expose a piezoelectric crystal which outputs a voltage corresponding to the acceleration of the vibration of the actuator; the driver circuit of the actuator reduces the driving voltage when the frequency of the voltage generated at the recess comes into the neighborhood of a higher resonance frequency of the actuator. The optical distance detector comprises a light-emitting diode and a pair of photodiodes which detects the amount of light incident thereon after being reflected at a surface of an object the distance to which is measured. The geometric parameters of the photodiodes are selected in such a manner that the output of a first photodiode decreases as the measured distance increases while the output of a second photodiode increases as the measured distance increases. Thus, the normalized differential output of the two photodiodes, from which the measured distance is determined, varies substantially linearly with respect to the measured distance. In preferred forms, the photodetectors have stepped concentric configurations so that small distances can be measured accurately and efficiently.

Dynamic Characteristics of Bimorph with Conducting Polymer Gel

Abstract: A bimorph consisting of poly(3-alkylthiophene) gel film and polypyrrole film has been prepared for the first time and demonstrated to be driven by electrochemical doping. The bend of the bimorph can be controlled by the doping potential, that is, by the dopant concentration. The response time can also be controlled by the doping potential and electrolyte concentration. Anomalous responses have been observed for excess doping levels. The origin of this unique behavior of the bimorph was discussed by taking the role of the dopant in the gel film into consideration.

Micromachined valve with hydraulically, actuated membrane, subsequent to a thermoelectrically controlled bimorph cantilever

Abstract: We report on the design, fabrication and performance of a micromachined valve for hydraulic applications. The valve is composed of a stack of four silicon wafers and utilizes a new actuation principle, which to our knowledge is presented for the first time in this paper: a fluid jet formed at a nozzle is passing along a bimorph cantilever; electrical actuation of this cantilever causes a deflection of the fluid jet towards a volume below a bossed membrane, where its kinetic energy is partially retransformed into pressure energy; this pressure lifts the membrane, thus opening the outlet hole of the valve; i.e., the valve is open or closed corresponding to whether the bimorph cantilever is heated or not. The outer dimensions of the valve are 14.5 × 8.5 × 1.43 mm 3 . It is designed for flow rates of about 75 ml/min at a system pressure level of about 6 bar. Efficient cooling of the cantilever by the fluid jet allows a maximum operating frequency as high as 1 kHz.

Equations of state including the thermal domain of piezoelectric and pyroelectric heterogeneous bimorphs

Abstract: The equations of state for piezoelectric bimorphs made of a piezoelectric and a non-piezoelectric material have been determined. As these bimorphs are nonsymmetric they suffer from considerable temperature sensitivity due to the difference in thermal expansion coefficients of the constituting materials. The deflection, rotation, volume displacement, charge on the electrodes and the entropy change have been calculated for the heterogeneous bimorph.

Study on Optical Servo System (Estimation of Dynamic Characteristics of Bimorph-Type Optical Actuator using PLZT Elements).

Abstract: A step response relating displacement to light intensity in a bimorph-type optical actuator consisting of two sheets of PLZT elements is analyzed theoretically, and the experimental equations on the principal parameters included in the theoretical equation of the step response are derived from the fundamental experiment on the PLZT elements with various sizes. Comparing the analytical result with the experimental result of the step response of an optical actuator manufactured as a trial, the results show linear and first-order lag factor characteristics and agree well with each other with regard to the final value of the displacement. The time constant in the analysis shows a value 0.44 times as great as that in the experiment. The cause for this difference is discussed in detail. If this cause is taken into consideration, the dynamic characteristics of a bimorph-type optical actuator may be estimated exactly by the analytical result shown in this paper.

Composite-shell finite element for the analysis of smart structures

Abstract: Smart structures with active ceramic segments typically consist of piezoceramic layers bonded to elastic members. Analytical modeling of piezoceramics has been addressed by many authors. Developments to date allow one to model planar structures and homogeneous piezoceramic continua. Most smart structures with piezoceramic control layers have multi- layered plate and shell geometries distributed in three-dimensional space. In this study, a composite shell finite element is developed for modeling such structures. The element developed is a general quadrilateral shell with eight nodes and curved edges. This paper describes the development of the element including a method for modeling the excitations to the bonded piezoceramic. Analytical and experimental results are presented for a commercial bimorph validating the performance of the element.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Production of piezoelectric bimorph

Abstract: PURPOSE:To suppress the decrease in electrostatic capacity of piezoelectric- ceramics accompanied with the curing of adhesives and increase the electrostatic capacity of piezoelectric bimorph after bonding by bonding a shim plate to piezoelectric ceramics by using an adhesive whose hardness is less than D50 and more than A20 of durometer after the adhesive has been cured. CONSTITUTION:Double oxide powder consisting essentially of zirconium, etc., is added with organic solvent, etc., slurried and formed into sheets in order to obtain green sheets. Then the green sheet is cut out to be like discs and it is sintered. The sintered body is processed to provide a silver electrode so as to form a piezo-electric ceramics 1 applied with polarization. Next, one side of either of two sheets of the ceramics 1 is printed with an epoxy adhesive 6 whose hardness is D40 of durometer when it has been cured. Further the piezoelectric ceramics 1 are bonded on both sides of a shim plate composed of phosphorous bronze plate and cured thereafter. Finally a united body of the ceramics 1 and the plate 5 is soldered to lead wires 3 and 4 to form a piezo-electric bimorph.

Dynamic behavior and shifting of resonance frequencies of ZnO on Si3N4 bimorphs

Abstract: The deflections of ZnO on Si3N4 bimorphs are quadratically dependent on the applied voltages. The fundamental resonance frequencies of the 2980 μm long bimorphs range from 140 Hz to 180 Hz. Resonances are also observed at sub-harmonics of the fundamental resonance frequencies. The resonance frequencies vary with the DC biasing voltages. The shifting of the resonance frequency can be explained by the change in the effective length of the curved bimorph, the stiffening of piezoelectric ZnO film by the biasing voltages, and the increase in the elastic compliance of the bimorph as a result of Joule heating. Air damping is observed with a cut-off frequency around 22 Hz.

Variable inductance coil

Abstract: PURPOSE:To obtain variable inductance coil which is simple in structure and excellent in mass productivity and capable of changing inductances electrically and promptly with less power consumption. CONSTITUTION:A bimorph type actuator 14 is mounted on a support base 12. The bimorph type actuator 14 comprises two piezoelectric devices 16 and 18, an inner electrode 20 and outer electrodes 22 and 24. The inner electrode 20 is connected to a terminal 26 while the outer electrodes 22 and 24 are connected to a terminal 28. A flexible coil 36 is mounted between an electrode 30 on the support base 12 and an electrode of the bimorph type actuator 14. Voltage is applied between the terminal 26 and the terminal 28 so as to displace the bimorph type actuator 14, thereby expanding and contracting the coil 36 and changing the inductances. The displacement directions and displacement variables of the bimorph type actuator 14 are controlled by controlling the polarity and voltage magnitude of the applied voltage.

Bimorph stepping motor for point‐contact experiments

Abstract: A rotating piezoelectric device, which uses the so‐called slip‐stick mechanism for micropositioning is presented. The device is especially designed for use in point‐contact experiments at very low temperatures in high magnetic fields. Two typical applications are presented.

A Fully Computerized Scanning Tunnelling Microscope

Abstract: A new, fully computerized and inexpensive, scanning tunnelling micro- scope was designed and built. Its key design feature is the application of the high sensitivity bimorph, for the coarse positioning of the bimorph is > 0.03 mm and can be divided up to the 12 bit number of steps. The bi- morph positioning implies that this microscope is fully computer controlled, and using of bimorph instead of inch-worm implies low cost of the unit. The microscope can create images of the surface in the constant current mode and in the imaging current mode. The presented microscope works with the z-axis analog or digital feedback loop optionally. All parameters of the analog and digital feedback loop are computer controlled. Due to the digital z-axis feedback loop benefits, electron tunneling spectroscopy mode is naturally accessible. The performance of the microscope was tested in air by imaging of surface of HOPG (high oriented pyrolytic graphite).

Cantilever type probe, its manufacture, scanning tunneling microscope and information processor using this probe

Abstract: PURPOSE:To provide a cantilever type probe at which the resist remnant and dust are not generated between respective layers of bimorph and whose adhesion is excellent without change of film quality at respective layer surfaces CONSTITUTION:At the manufacture of a cantilever type probe that provides an information input/output probe at the upper surface free end portion of a cantilever like displacement having two layer piezoelectric body films 4, 5 and three layer electrodes 6,7, 8 whose purpose is to displace piezoelectric body films by means of piezoelectricity inverse effect, two layer piezoelectric body films 4, 5 and three layer electrodes 6, 7, 8 are conducted with film formation continuously in a vacuum device

Micro hand mechanism

Abstract: PURPOSE:To move a micro hand used for assembling of optical elements, optical parts, etc with the simple and inexpensive structure and relatively low voltage in a large movable range CONSTITUTION:On a peripheral face of a rod-state member 1 made of an elastic body, a thin plate-state piezoelectric element (bimorph) 5 made of a polymer piezoelectric material and a piezoelectric actuator 2 provided with an electrode 6 for applying a voltage to this thin plate-state piezoelectric element totally or partially are provided When the voltage is applied, the piezoelectric actuator 2 is bent, resulting in deformation of the rod-state member 1 A micro part such as an optical part is held by a plurality of the rod-state members 1 to carry out connection, assembling, etc By changing arrangement pattern or arrangement number of the piezoelectric actuator, electrode pattern or electrode applying pattern, movement with much freedom can be obtained The actuator itself is soft and can softly holds breakable parts

Apparatus and method for measuring limit dimension

Abstract: PURPOSE: To measure the depth and width of a trench in a sample by containing the data signal of the physical relationship of a probe to a sample, vibrating the probe on the sample surface and obtaining output signals. CONSTITUTION: Wideband white light from a white light source 34 passes a beam splitter 38, is reflected by a sample 12, returns to the beam splitter 38, and is detected by a video camera 36, etc. The location of a probe can be detected by using an optical microscope. A bimorph piezoelectric element 48 vibrates an installed cantilever 16, and the cantilever 16 vibrates a probe tip 14 in the direction of Z. And the bimorph piezoelectric element 48 moves in parallel in the direction of 'Z', lowers the tip a trench 40 over the sample or a target 12 or to a trace width 42, and follows the surface geometry of the sample 12 when the sample 12 is scanned. The whole the profile of the surface area can be mapped by moving the tip 14 across a trench 40, trace width 42 or both of them.

Resonant frequency of a polyvinylidene flouride piezoelectric bimorph: the effect of surrounding fluid

Abstract: This work presents experimental and theoretical results on the dynamic behavior of piezoelectric cantilever bimorph in the presence of surrounding air. The bimorph is composed of a pair of piezoelectric sheets bonded by a uniform elastic layer of adhesive in the center. The transverse motion of the bimorph is generated by a sequential application of two opposing electric fields on the piezoelectric sheets. Theoretically, the tip deflection and the natural frequency of the bimorph are obtained making use of an energy balance technique. The fluid in modeled as inviscid and incompressible whose motion induces locally additional mass in the transverse direction. An expression for the kinetic energy of the system is derived based on this additional mass from which the natural frequency of the combined system is obtained. Tests were performed on the piezoelectric bimorphs with similar geometries and varying adhesive thickness in a vacuum chamber. The air pressure in the chamber was varied from 10 kPa to one atmosphere. Good agreements between the theoretical predictions and the observed values were obtained. This study could have applications in the use of piezoelectric materials for fluid property measurements.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Manufacture of bimorph type piezo-electric vibrator

Abstract: PURPOSE:To reduce the manufacturing cost of the title vibrator by reducing the working man-hour. CONSTITUTION:A bimorph type piezo-electric vibrator 10 is manufactured in such a way that, after a pair of large-area base plates 1 for piezo-electric elements and a pair of large-area metallic base plates 2 are prepared and the plates 1 and 2 are stuck to each other, with the base plates 2 being put between the base plates 1, the laminated body 3 is cut into pieces having desired areas and prescribed shapes.

Two-camera phase measurements using phase-stepped real-time holographic interferometry

Abstract: A multiple detector method was developed to extend the capabilities of phase stepped, rea1time holographic interferometry to measure two components of a displacement vector simultaneously. To testthe method, two experiments were performed which measured the cantilever bending of a piezoelectricceramic bimorph due to an applied voltage. For the first experiment, the optical axis of one of the cameraswas perpendicular to the surface of the bimorph while the optical axis of the second camera formed anangle of 48° 1 ° withrespect to the optical axis of the first camera. The bimorph was then rotated so thatthe angle between the optical axis of the first camera and the surface normal changed by 20° 1°. Boththe out.ofp1ane (normal to the surface) and one of the in-plane (tangential) displacement componentswere resolved for each experiment and the results were compared with the known values. 2. INTRODUCTION Previously, we have applied phase stepped, rea1time holographic interferometry in an attempt to measurethe converse piezoelectric effect in bone.1'2 The precision of this method, implemented using off the shelfcomponents and custom designed software, is at least 5 nm at every pixel over a large field of view.1Either spatial or temporal averaging can be used to improve the precision.3'4 In all of our previous work,

Rotary or linear motor, in which armature is driven by ultrasonic vibration

Abstract: PURPOSE: To provide a rotary or linear electric motor that is excited piezoelectrically by using only one bimorph piezoelectric element as an actuator CONSTITUTION: In a rotary or linear electric motor with an armature core 9 that is driven by a piezoelectric means for generating ultrasonic waves, a piezoelectric means is set to vibration by a high-frequency alternating voltage and is pressed against the friction surface of an armature 9, a single vibration element 1 is provided in a layer and has piezoelectric material thin lines (a) and (b) with electrodes 3a, 3b, and 3c, an alternate voltage that affects the element is applied to each thin line of the vibration element according to a vibration mode that shifts each other for generating the rotary movement of the vibration element in contact with a friction surface 9a, and voltages differ including in their signs

Manufacture of cantilever drive mechanism, manufacture of probe drive mechanism, and cantilever drive mechanism, probe drive mechanism, and multiprobe drive mechanism, scan type tunnel microscope and information processor using the same

Abstract: PURPOSE:To obtain a cantilever drive mechanism allowed to be integrated without impairing any cantilever drive characteristic by forming a part of a cantilever after the formation of a circuit section to drive the cantilever. CONSTITUTION:An oxide film is produced on a substrate as first insulation layer using an n-type as substrate 1 to form a LOCO layer 2. A gate electrode 4 is formed and a layer insulation layer 3 as second insulation layer. An aluminum-silicon film is produced for wiring with a transistor or the like of a circuit section to form a wire layer (electrode layer) 6. An SiON film is made to be a protective film 7. Chromium and gold are made into a film as a ground electrode layer 9 of the layers composing a cantilever. After the formation of a film as piezo-electric layer 8 from zinc oxide. gold and zinc oxide are made into a film to enable the building of a bimorph structure of the electrode layer 9 and the piezo-electric layer 8 by lamination. Parts of the piezo-electric layer 8 and the protective layer 7 are removed for an electrode of a cantilever section and for connecting an electrode to a circuit section. A contact hole is formed. Then, aluminum is made into a film to form a connection electrode layer 10.

Magnetic recording/reproducing device

Abstract: PURPOSE:To decrease a necessary displacement amount of a head driving actuator CONSTITUTION:To microcomputers 36, 46, a head switching signal (e), a CTL pulse (f), a CFG signal (g), a segment detecting signal (h), a dynamic tracking detecting signal (i), a capstan rotational direction detecting signal (j), and a field frame detecting signal (k) are supplied Also, the microcomputer 36, 46 predict a head driving locus of video heads 32, 33, 42 and 43 from the supplied signal, and generate a first and a second bimorph plate control digital signals (l), (m) so that bimorph plates 31, 42 select a recording track in which the maximum displacement amount of a head driving actuator becomes the smallest at the time when the recording track is traced In such a way, the necessary displacement amount of the head driving actuator can be decreased