Showing papers on "Bimorph published in 1980"

Flexural–extensional behavior of composite piezoelectric circular plates

Abstract: A plate‐type theory is developed for the flexural‐extensional vibratory response and static voltage deformation of heterogeneous piezoelectric circular transducer elements. Known results for homogeneous disks and bimorphs are shown to be special cases of the theory. Application is made to the design of simply supported metal‐piezoceramic unimorph disks, and thin piezoceramic bimorph benders possessing metallic electrodes of non‐negligible thickness.

Thick optical element having a variable curvature

Abstract: The optical element comprises a first bimorph structure, at least one of the components of which is made from piezoelectric material and supply electrodes for the bimorph structure. The element further comprises at least one reinforcing piezoelectric bimorph structure provided with supply electrodes. The latter are respectively connected to the electrodes of the first bimorph structure. An element of the reinforcing bimorph structure is placed against a corresponding element of the first bimorph structure and fixed thereto by a layer of an elastic material. The latter has a tensile strength which is low relative to that of the elements constituting the bimorph structures of piezoelectric material.

Bimorph transducer made from polymer material

Abstract: The invention relates to bimorph electromechanical transducers made from polymer material. It specifically relates to a transducer comprising a plurality of superimposed dielectric sheets for forming a bimorph structure, whose deformations are controlled in linear manner by a voltage. None of the sheets is piezoelectric. The linearity of operation is obtained because at least one of the dielectric sheets carries a permanent electric charge. The invention is applicable to the construction of microphones, telephone receivers, loudspeakers, as well as to the construction of optical components, whose precise, small displacements it is desired to control.

Piezoelectric electro-mechanical bimorph transducer

Abstract: An electro-mechanical transducer having a first layer made of piezoelectric material having opposing major surfaces, a pair of electrodes formed on the major surfaces of the first layer, respectively, and a second layer clamped at its one surface to one of the surfaces of the first layer. In this case, the first layer has a Young's modulus of E, the second layer has a Young's modulus Ex in one direction and a Young's modulus Ey in the direction perpendicular to the one direction in the major surface, the Young's moduli E, Ex, Ey satisfy the relation E>Ey, Ex>Ey, and one end of the first and second layers along the one direction is clamped. The thickness of the electrode is selected between 0.1 and 3 μm to obtain large amount of displacement at the other end. The outer surface of the electrode may be coated with a conductive paste to ensure voltage supply to the whole surface of the electrode.

Piezoelectric light beam deflector

Abstract: An optical apparatus for the deflection of a stationary beam of light to move the beam over two mutually perpendicular directions for projection onto a viewing screen. By suitably modulating the beam of light, images may be produced on the screen, as in the manner of TV images. The apparatus is defined by a piezoelectric bimorph of a known type which has been modified according to this invention so as to make each bimorph layer totally internally reflecting. The light deflection apparatus, also according to this invention, is made from a single bimorph provided with an extension of lesser mass and hence of lesser inertia. The main bimorph portion is electrically stimulated to oscillate it in a vertical (Y-axis) direction, and the extension is electrically stimulated to move it in a horizontal (X-axis) direction. The stationary beam of light is projected through the bimorph and onto the screen.

Bimorph piezoelectric element

Abstract: PURPOSE:To obtain an excelent characteristic by controlling unwanted vibration by means of an electric layer provided between piezoelectric ceramic elements CONSTITUTION:Piezoelectric ceramic elements 110 and 120 made of PZT or a three-component material are bonded 3 through an elastic layer 4 The elastic body uses a material with a Young's modulus of 1X10 -5X10 (N/m ) The thickness and size are properly selected for the material employing a thin lead sheet, a solder sheet, a polyethylene sheet or the like depending on the material, shape and the like of the piezoelectric element Provision of a partial void in the elastic layer or using in a honeycomb construction is also effective With such an arrangement, there is no need for limiting the deflecting range of the element while unwanted vibration can be removed or damped This provides an element with a better responsiveness at a low cost without use of a special circuit for the driving circuit

Piezoelectric ultrasonic transducer mounted in a housing

Abstract: An ultrasonic transducer comprises a vibrating assembly having a thickness-poled piezoelectric ceramic disk (12) bonded concentrically to a resonant plate (13) of greater diameter than that of the ceramic disk (12), which having a radiator (30) is set in the center of the resonant plate (13) on the opposite surface to the ceramic disk (12), and which fitted onto a plastic baseplate (51) using such adhesive (52) as will retain elasticity after curing and accommodated within a housing (80) with a director (81) on top. The ultrasonic transducer has superior performance to conventional bimorph devices by 6 dB in terms of receiving sensitivity.

Large area display element using PVF2bimorph with double-support structure

Abstract: The bending properties of a double-support PVF2 bimorph cantilever structure were investigated theoretically and experimentally. Decreased drive-voltage and gravity sag deformation were confirmed. Using the analytical result, it is possible to design a PVF2 double-support structure for specified conditions of display area, response time, driving voltage, and gravity sag deformation. Typical properties of a double-support bimorph with 9 μm-thick PVF2 layers, 4 cm in total length, are: 120 V drive-voltage, 60—100 msec response time, and ±1.8 cm deflection.

Magnetic recorder and reproducing device of rotary head type

Abstract: PURPOSE:To make an accurate scan on a recording track by equipping a rotary magnetic head on a bimorph cell with electro-strictive effect and by limiting the height position of a magnetic head in a contactless period of a magnetic tape. CONSTITUTION:Magnetic tape 28 runs around head cylinder 30. Head 31 is fixed to the head cylinder thrugh piezoelectric-element bimorph cell 32, but in case of a two- head system, one head is free while the other head is in operation of recording a signal on the magnetic tape. To the head in no contact with this magnetic tape, head positioning head 33 is provided closely and a signal is transferred from oscillator 36 through amplifier 37 to provide a magnetic field. Bimorph element 32B vibrates mechanically magnetic head 31B and its head signal is supplied to bimorph driver circuit 40B to detect the position by magnetic head 31B, so that accurate tracking will be carried out.

Transparent plane plate speaker

Abstract: PURPOSE:To improve the frequency characteristic, by making a diaphragm elliptic in a plane plate speaker using a piezoelectric crystal plate. CONSTITUTION:The transparent plane plate speaker consists of bimorph vibrator 1, transparent electrodes 20 and 21, transparent ceramic piezoelectric crystal thin plates 11 and 12, etc. The frequency characteristic of the small-size plane plate speaker is affected greatly by the form of the diaphragm. The diaphragm is shaped into the elliptic form or the form obtained by chamfering vertical angles of the polygon circumscribed on or inscribed in the ellipticity, thereby improving the frequency characteristic.

Supporter for magnetic head

Abstract: PURPOSE:To increase contact pressure while evading the generation of an error of a contact angle to a tape on the gap surface of a head chip by employing the electrode structure which has two piezoelectric materials extending in the length direction at the tip part of the fitting/fixing side of a bimorph plate. CONSTITUTION:Bimorph plate 12 is fitted as a one-end-held beam to the fixing part of head base 13, etc. To constitute this bimorph plate 12, two plates 14a and 14b made of piezoelectric material are bonded together in a body by adhesive 18, etc., at half their parts on the base end 12b side, i.e., part 12B on the base end side while center reinforcing metal plate 15 serving as an intermediate electrode is interposed and further bonded directly at the remaining part on the tip 12a side, i.e., part 12A on the tip side of bimorph plate 12. Consequently, the generation of an error of a contact angle to a tape can be evaded and contact pressure can be increased.

Support structure of magnetic head

Abstract: PURPOSE:To reduce the contact angle error between a magnetic tape and a head chip to reproduce stable pictures by providing electrodes only in the base end part without forming the electrode for electrostrictive drive at the tip part of a bimorph plate CONSTITUTION:Bimorph plate 31 is fitted as a one end-supported rod with the base end supported to fixing means 32 such as a head base stand This bimorph plate 31 is constituting by causing two plate-shaped materials 33 and 34, which are formed into a trapezoidal form by ferrodielectric materials, to adhere to each other through center metallic plate 30, which is used as an intermediate electrode also and becomes a reinforcement plate, by adhesive, etc On the surface and the reverse face of bimorph plate 31, electrostrictive driving electrodes 35 and 36 are formed in base end part 37 from the part near the base end, which is the support part for fixing means 32, to the center Then, head chip 38 is fitted to tip part 39 where no electrode is provided so that chip 38 may be protruded from tip part 39

Large area electronically controllable light shutter array using PVF2bimorph vanes

Abstract: A new type of electronically controllable venetian blind-type light shutter array using PVF2 bimorph devices was constructed and demonstrated. Such an array may be used as an electronically-controlled window blind for solar energy control, general convenience, or for large-scale displays. Each of the nine bimorph device elements used in the demonstration array was 2.5 cm in length, 10 cm in width, and 15 μm in thickness. The 2 cm spacings between the device strips are completely closed by the device bending action caused by the application of 140 volts dc derived from rectified mains ac. The switching time is about a quarter of a second.

Method of suppressing selffoscillation of electromechanical converter

Abstract: PURPOSE:To abruptly displace a bimorph without self-oscillation in an electromechanical converter by superimposing second drive voltage having the same period, amplitude and 180 deg. of phase difference as and from the self-oscillation components in the first drive voltage to the first drive voltage. CONSTITUTION:When predetermined voltage 22 is stepwisely applied to a bimorph, it can respond with a wave 23 of T/2 with self-vibration period T until the initial peak value due to the transient theory. When the Q factor of the bimorph is approx. 10, the excessive amount is approx. 1, and the amplitude sigmat1 is twice the ideal displacement sigmas1. Accordingly, the bimorph is displaced by sigmas1/2 by the pulse 24. The response of the bimorph for the pulse waveform 24 is the synthesized negative and positive stepwise voltage 25 and 26, and the responses to the respective voltage becomes self-oscillation with the period T and the amplitude sigmas1. Therefore, when synthesizing them by taking into consideration with the symbolts, the bimorph responds with the waveform 29. When it is now driven by the synthesized waveform 20 of the pulse 24 and the stepwise voltage 22, the transient response of the bimorph becomes the waveform 31. After the rise time of the T/2 period the displacement sigmas1 becomes constant to abruptly displace without self-oscillation.

Mechanical fibre optic switching using p.v.d.f. bimorph

Abstract: An optical fibre switching element has been constructed, based on the electromechanical deformation of a bimorph of piezoclectric polymer, p.v.d.f. (polyvinylidene fluoride). Light transmitted through a fibre was switched between two other fibres situated next to each other by the application of the voltage of 3.5 V r.m.s. at 10 Hz. The insertion loss of this element was 0.7 dB.

Rotary head type magnetic picture recording and reproducing device

Abstract: PURPOSE:To position a head with a simple constitution and make recording as well as reproducing possible with the same head, by applying a fixed DC voltage to a bimorph to cause deflection in one direction at a recording time and by bringing the bimorph into contact with the protruded part which controls head height. CONSTITUTION:Protruded part 11 formed with a high precision by hard materials such as ceramic is provided at the tip part of head fixing substrate 9 having a sufficient mechanical strength, and magnetic head 34 is fixed to the tip part of bimorph 10, and bimorph 10 and substrate 9 are linked with each other through insulating plate 12 in one end parts by a screw so that they may be parallel with each other. At a recording time, a fixed DC current is applied to bimorph 10 to cause deflection so that protrusion 11 of the fixing substrate may be brought into contact with bimorph 10, thereby controlling the position of magnetic head 34. By the simple constitution like this and by the same head, recording and reproducing can be performed.

Fabricating method of bimorph made of high molecular film

Abstract: PURPOSE:To adapt for large and continuous mass production of bimorphs by exposing one end of a conductive film interposed between high polymer films from the bonded surfaces of the films and using it as the electrode terminal of internal pressure electrodes when forming a bimorph through bonding the even number of the high molecular films. CONSTITUTION:Conductive films 2a, 2b are coated on both sides of a high molecular film 1 polarized to become piezoelectric and made of polyvinylidene fluoride resin or the like. The piezoelectric films 1, 1' thus formed are interposed with a conductive film 3 therebetween and bonded with adhesive 5. At this time the film 3 is provided not on the entire surface therebetween, the end of the film 3 is projected from the bonded surfaces, and the end is used as the exposed electrode terminal 4 of the internal pressure electrode. Thus, the termial 4 is readily formed, and soft high molecular piezoelectric film 1 may not be scratched.

Magnatic recording and reproducting device

Abstract: PURPOSE:To prevent an influenece of husteresis of a bimorph plate at the time of a height adjustment of a rotary magnetic head by adjusting the height position of the magnetic head through the bimorph plate while an attenuating alternating-current voltage, etc, is applied across the bimorph plate CONSTITUTION:Applying the bimorph plate with an alternating-current voltage damping from voltages values V2 and -V2 results in that the free terminal of the bimorph plate becomes an intermediate point position with the largest residual displacement value after the application of the maximum voltage between V2 and -V2, eliminating residual hysteresis of the bimorph plate The height position of the head can therefore be adjusted accurately and automatically via the bimorph plate by regarding a non-hysteresis state as an initial position Further, applying a positive or negative cyclic votage across the bimorph plate can reduce the influence of hysteresis in the same way

Manufacture of bimorph

Abstract: PURPOSE:To enhance the mass production of small bimorph by exposing a part of an internal electrode from the bonded surfaces of even number of high molecular films having piezo-electric property to be used as an electrode terminal when forming the bimorph by bonding the films CONSTITUTION:Conductive films 2a, 2b are coated at both sides of a film having piezo-electric property upon polarizing like polyvinylidene fluoride resin to form a piezo-electric element When two such piezo-electric elements 1a, 1b formed thus are superimposed, one element 1b is formed smaller than the other element 1a, a surface electrode of film 2'a formed on the element 1a is extended outer than the internal electrode made of film 2b formed on the element 1b When the surface electrode thus extended is used as the exposed electrode terminal 4 of the internal electrode, it can eliminate the bonding of the electrode to the bonded surfaces of the films to prompt the production with low cost

Head support unit in recording and reproducing device

Abstract: PURPOSE:To make it possible to maintain well the contact between a magnetic head and a magnetic tape and improve a recording and reproducing efficiency by fitting the magnetic head to the tip of a pair of bimorph plates approximately parallel to each other through a rubber material. CONSTITUTION:Magnetic head 44 is fitted to the tip of a pair of bimorph plates 30 and 32 approximately parallel to each other through an elastic deformable buffer material and step parts 42a and 42b of rubber material 42. Therefore, in case that bimorph plates 30 and 32 are much bent, step parts of rubber material 42 are deformed elastically according to this bend. Consequently, magnetic head 44 can be moved vertically while being held in the approximately horizontal state, so that the contact between contact face 44a of magnetic head 44 and the surface of magnetic tape 60 can be maintained well. Then, since vibration of the unit generated by return of magnetic head 44 from the maximum movement position to the center position is buffered, by rubber material 42, the unit can be operated stably without flickering, etc., of the reproducing video dependent upon vibration.

Branching device of light combining piezoelectric element and optical fiber

Abstract: PURPOSE:To perform changing over of optical fibers through the use of curving displacement of piezoelectric elements using polyvinylidene fluoride by affixing said piezoelectric elements and applying multistep voltages thereto. CONSTITUTION:The free end of a movable optical fiber 3 whose one end is fixed and other end is made free and stationary optical fibers 1, 2 are opposed with their optical axes being aligned. The free end of the fiber 3 is then moved in the + or -x axis direction to be coupled to the fiber 1 or 2. At the time of driving the fiber to accomplish this changing over, the piezoelectric elements 4A, 4B using polyvinyliden fluoride are bonded to a bimorph structure, and when electric fields are so applied that the element 4A elongates and the element 4B contracts, then the bimorph bends downward. The fiber 3 is displaced by making use of this displacement to couple the fiber 3 from 1 to 2. When the applied electric fields are made zero, the fiber 3 resets to the coupling to 1 from 2.

High Bandwidth, Fine Resolution Deformable Mirror Design.

Abstract: : This report describes the design, fabrication and testing of five candidate actuator types to achieve a deformable mirror capable of 6 microns dilatation at 1.5 kV. The actuator types are the coherent stack, bimorph, tube, multilayer and the honeycomb.

Magnetic recording and reproducing unit

Abstract: PURPOSE:To halve the noise band on the reproduced screen, by changing the mechanical height of the magnetic head with the envelope signal of reproduced FM modulation wave at fast feed and reversal fast feed. CONSTITUTION:The reproduced FM modulation wave fed to the terminal 28 is taken as the envelope signal via the amplifier 29, and detection circuit 30. This envelope signal is converted into the waveform near the sinusoidal wave at the band pass filter 31. This signal is fed to the phase correction circuit 32 to correct the azimuth angle and the phase shift produced in the control system. The corrected signal is given to the bimorph drive circuit 33 to change the mechanical height of the magnetic head via the bimorph 34. Thus, the noise band amount is lowered without using the damper member.

Automatic focus adjusting device of microscope

Abstract: PURPOSE:To provide the device which is capable of adjusting focus with low voltage without vibrations by mounting the objective lens of the microscope to bimorph type piezoelectric elements and providing a means of detecting the focus position and driving the element and a detecting means for lens movement amount CONSTITUTION:The slide glass specimen 1 of the microscope is magnified by an objective lens 2 and is photo split by a beam splitter 6 The split beams form the image on the photo detecting plane of a one-dimensional image sensor 7 The optical density image is converted to an electric signal which is then converted to a focus position detecting signal in an analog signal processing part 8 The focus position is detected in an automatic focus adjustment control part 10 Driving of the objective lens part is accomplished by applying voltage to the bimorph construction comprising affixing together two sheets of piezoelectric elements 3, 4 Although the amount of deflection varies with the applied voltage, the material of an elastic plate 5 and others, the size adjustment of about 10mu may be readily performed through voltage application of + or -100V

Recording and reproducing device for flexible magnetic sheet

Abstract: PURPOSE:To reduce damages of a magnetic sheet and magnetic head with stable output, by making it possible to move the head into the best contact state corresponding to the floating state of the magnetic sheet by making it possible to vary the rotational frequency of the magnetic sheet CONSTITUTION:To the shaft of motor 10, the center part of magnetic sheet 13 on stable plate 12 is fixed by fixture 11 Magnetic head 14 is fixed to bimorph plate 15, the other terminal of which is fixed 2nd bimorph plate 16 with its other terminal fixed to fixed table 17 As motor 10 is driven by rotation control circuit 18, magnetic sheet 13 rotates along stable plate 12 When sheet 13 moves from position (b)-(a) through the rotation, command circuit 19 drives bimorph driver circuit 20 and magnetic head 14, moved in X and Y directions by bimorph plates 15 and 16, comes in the best contact state with magnetic sheet 13 Consequently, the output of the magnetic head is stabilized and damages of magnetic sheet 13 and magnetic head 14 can be reduced

Electroomechanical converting element unit

Abstract: PURPOSE:To simplify a process of manufacture with the need for the wiring of a circuit eliminated by providing an electric signal detection part to the tip of an electro-mechanical converting element using piezoelectric plates, by controlling the position by a driving voltage applied across the converting element, and by providing a driving circuit for the driving voltage on the piezo-electric plate. CONSTITUTION:Bimorph plate 11 for magnetic head unit 12 for a video tape recorder is composed of an electro-mechanical converting element using two piezoelectric plates 13 and 14. To the tip of bimorph plate 11, video head 16 is fitted which records and regenerates video signals, and its base end part is fixed to rotary drum 18 via head base 17. Further, storage gauge 19 is bonded nearly in the center of bimorph plate 11. On part of the surface of piezoelectric plate 13 of bimorph plate 11, a conductive metal layer as an electrode is removed and circuit elements 30, 33, 34, 35 and 37 are integrally provided which constitute a bimorph driven circuit part, recording regenerative head amplifier circuit, displacement detection circuit part, etc.

Manufacture of piezoelectric bimorph

Abstract: PURPOSE:To eliminate the step of bonding and to improve the moldability of a piezoelectric bimorph by forming a piezoelectric material having two-phase structure by thermal pressing or coating and then polarizing it. CONSTITUTION:Vinylidene fluoride-ethylene trifluoride copolymer or high molecular material having it as a main ingredient is thermally pressed in a film shape or coated in solution state on a film-shaped high molecular and inorganic composite piezoelectric material to form a piezoelectric material having two-phase structure. Thereafter, it is polarized. Reverse polarity piezoelectric property is imparted thereto by forming two-phase structure with the vinylidene fluoride-ethylene trifluoride copolymer and high molecular and inorganic composite piezoelectric material and thereafter applying DC electric field thereto to polarize it, and a both-side bimorph structure can be obtained.