US2484635A - Piezoelectric crystal apparatus - Google Patents

Piezoelectric crystal apparatus Download PDF

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Publication number
US2484635A
US2484635A US637127A US63712745A US2484635A US 2484635 A US2484635 A US 2484635A US 637127 A US637127 A US 637127A US 63712745 A US63712745 A US 63712745A US 2484635 A US2484635 A US 2484635A
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Prior art keywords
crystal
thickness
axis
motion
piezoelectric
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US637127A
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English (en)
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Warren P Mason
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AT&T Corp
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Bell Telephone Laboratories Inc
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Priority to BE472576D priority Critical patent/BE472576A/xx
Priority claimed from US497883A external-priority patent/US2450010A/en
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US637127A priority patent/US2484635A/en
Priority to US637126A priority patent/US2450011A/en
Priority to GB34524/46A priority patent/GB641469A/en
Priority to FR938529D priority patent/FR938529A/fr
Priority to GB37773/46A priority patent/GB641471A/en
Priority to GB37772/46A priority patent/GB641470A/en
Publication of US2484635A publication Critical patent/US2484635A/en
Application granted granted Critical
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02007—Details of bulk acoustic wave devices
    • H03H9/02015—Characteristics of piezoelectric layers, e.g. cutting angles
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02007—Details of bulk acoustic wave devices
    • H03H9/02157—Dimensional parameters, e.g. ratio between two dimension parameters, length, width or thickness

Definitions

  • FIG. 3 PIEZOEL ECTRIC CRYSTAL APPARATUS Original Filed Aug. 9, 1943 NH4 H2 P04 Z kH P04 I NH4 H2 As 0 I KHZ A! 0 1 l L" YUM X) 1 X (on r) I Z Z ar TENS/0N)
  • FIG. 3 PIEZOEL ECTRIC CRYSTAL APPARATUS Original Filed Aug. 9, 1943 NH4 H2 P04 Z kH P04 I NH4 H2 As 0 I KHZ A! 0 1 l L" YUM X) 1 X (on r) I Z Z ar TENS/0N)
  • FIG. 3 PIEZOEL ECTRIC CRYSTAL APPARATUS Original Filed Aug. 9, 1943 NH4 H2 P04 Z kH P04 I NH4 H2 As 0 I KHZ A! 0 1 l L" YUM X) 1 X (on r) I Z
  • This invention relates "to piezoelectric -crystal apparatus and particularly to thickness shear mode piezoelectric crystal elements comprising crystalline ammonium "dihydrogen phosphate (NHiHzPOi), potassium 'dihydrogen phosphate (KH2PO4), ammonium dihydrogen arsenate (NH4H2ASO4), potassium dihydrogen arsenate (KHzASOi) and isomorphous combinations.
  • NHiHzPOi crystalline ammonium "dihydrogen phosphate
  • KH2PO4 potassium 'dihydrogen phosphate
  • NH4H2ASO4 ammonium dihydrogen arsenate
  • KHzASOi potassium dihydrogen arsenate
  • Suchcrystal elements are useful as electromechanical transducers utilized, for example, in sonic or supersonic projectors, microphones, pick-up devices and detectors. Also, theymay be utilized asfrequency control elements in electric wave filter systems, oscillation generator systems and amplifier systems. Other applications for such crystal elements may include harmonic producers, and, in general, any application Where either a resonant or nonresonant piezoelectriccrystal element may be utilized.
  • the non-linear hysteresis loop characteristics of the non-resonant crystal may bemade use of to produce overtones or harmonics therefrom.
  • One ofthe objects of this invention is to provide useful orientations and modes of motion in crystal elements made from crystalline ammonium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen arsenate, potassiumddihydrogen -arsenate and isomorphous combinations. or ii H I M
  • Otherobjects of "this invention are to provide crystal elements comprising dihydrogen phosphate and arsenals substances that may possess useful characteristics, such as large piezoelectric constants, large'vibrational motion, minimum coupling of the'desired mode of motion with undesired "modesof motion therein, and temperature coefiicients of frequency that may'h'ave'th'e relatively lower values.
  • I V u Another object "of this "invention is to 'take advantageof the high piezoelectric activity, the low cost and other advantagesof crystalline amhydrogen phosphate -and arsenate crystals.
  • Crystal elements of suitable orientation "but from crystalline ammonium dihydrog'en "phosphate/potassium dihydrogen phosphate, potassium dihydrogen arsenate, ammonium dihydrogen arsenate and isomorphous combinations thereof maybe excited in dififerent modes of motion, such as longitudinal length, longitudinal width or longitudinal thicknessmodes of'moeen,
  • Crystal elements composed of crystalline ammonium dihydrogen phosphate, potassium dihydrogen phosphate, potassium dihydrogen arsenate, ammonium 'dihydro'gen' arsenate and isomorphous' combinations may have piezoelectric and elastic cbnstants'onmoduli of considerable interest for use inelectromechanical transducers,
  • crystal cuts are pro- 'vided that may he 'utilized for these purposes and-others.
  • the t'y'pes of crystal cuts may be divided into several categories, 'suchas (a)'crystal cuts that have "relatively large piezoelectric 'constantsandherice maybe driven strongly'piezoele'ctrically, (b) crystal cuts 'that have advantageous "elastic -properties, "such that the long-itudinal'face modes of motion therein are free from” coupling to' the faceshear modes of motion therein, and face shear mode crystal elements that "are free from coupling'with other modes ofmotion therein; and (c) crystal cuts that may have the-relatively lower values of temperature coeflicients of frequency.
  • Crystal elements comprising ammonium dihydrogen phosphate, p'otassium dihydrogen phosphate, ammonium -dihydrogen arsenate, potassium' dihydrogen arsenate and isomorphous combinations also possess I ferroelectric properties such as large dielectric constants, hysteresis loops andnon linearity ofcharge field.
  • the temperature coefficients of frequency for certain of theprincipal cuts are roughly of the order of 100 to 300 parts per million per degree centigrade;
  • the dielectric constants decrease slightly with an increase in temperature while the piezoelectric constants relating charge and stress are nearly independent of temperature. Since the ammonium dihydrogen phosphate crystals have the relatively higher values of electromechanical coupling, and are free from water of crystallization which eliminates dehydration in the crystal, and will stand relatively high operating temperatures of the order of 180 C., or more, they are useful as driving elements for all transducer applications, such as projectors and microphones in underwater sound work, for example.
  • this type of crystal may be used as a substitute for quartz frequency control elements in filter and oscillator applications, especially when ;used with temperature control.
  • the crystal cuts having the relatively lower temperature coefficients of frequency may be used at ordinary temperatures without temperature control.
  • ammonium dihydrogen phosphate crystal elements may be constructed to have the largest values of piezoelectric constants of the four crystalline dihydrogen phosphate and arsenate salts mentioned, and also generally, are relatively more easy to grow in the sizes and shapes that are useful for cutting crystal elements therefrom.
  • crystal elements disclosed in this specification may have conductive electrode coatings on their major surfaces of any suitable composition
  • Fig. 1 is a perspective view illustrating the prismatic tetragonal-scalenohedral form in which ammonium dihydrog'en phosphate, potassium dihydrogen phosphate, potassium dihydrogen arsenate, ammonium" dihydrogen arsenate and isomorphous combinations thereof crystallizes, and also illustrating the relation of the prism faces and cap faces 'of such crystalline substances with respect to the mutually perpendicular electric axis -X, mechanical axis Y, and optic axis Z thereof;
  • Fig. 2 is a perspective" view illustrating the orientation, in terms of the angles 1;), 0 and ill, of a crystal element cut from any of the dihydrogen crystalline substances illustrated in Fig. 1, and may be taken to illustrate the orientation of any dihydrogen salt crystal element disclosed in this specification; and
  • Figs. 3, 4 and 5 are perspective views illustrating the orientations of several types of thickness shear'mode crystal elements cut from any of the substances ammonium dihydrogen phosphate,
  • the (Z36 piezoelectric constant means that a Z axis field represented by the numeral 3 may produce XY shear motion represented by the numeral 6. If the d36 piezoelectric constant of the substance has a large value, as it does in thecase of the several dihydrogen salt crystals here considered, then a Z axis fieldapplied thereto may produce a strong shear motion in the XY plane of the crystal body.
  • the value of the elastic compliance and shear stiffness for rotated crystal elements may be calculated from the fundamental elastic matrix given in Equation 1 in my parent application hereinbefore referred to; One method of doing this is by the short-hand matrix method discussed in a paper The mathematicsof crystal properties, by W. L. Bond, Bell System Technical Journal, January 1943, page 1, using the matrix Where the axes X, Y and Z of the rotated crystals are related to the crystallographic axes X, Y and Z by the direction cosines 21 to m, 11 being the direction cosine between X and X, m the direction cosine between Z and Z, etc. As'shown by Bond, the elastic compliances of rotated crystals are given in terms of the elastic compliances of unrotated crystals by the product of the matrices.
  • the direction cosines that cause the length dimension L of the crystal element to point in the desired direction are used.
  • the system of angles illustrated inFig. 2 is used where the length L of the crystal is taken along the X axis, the width W is taken along the Y axis and the thickness T is taken along the Z axis.
  • the angle measures the angle between the Z crystallographic axis and the Z thickness T axis.
  • the angle (p measures the angle between the XZ plane and the Z2 plane and 1 1/ the skew angle, is the angle between the length dimension L of the crystal and the tangent to the great circle through the Z and Z areas.
  • the mother crystal l illustrated in Fig. 1 may be grown from any suitable substances, and in any suitable manner such as, for example, by'
  • the potassium salts, used in growing the mother crystal I illustrated in Fig. 1 may be obtained from potassium hydroxide and phosphoric or arsenic acid, and the ammonium salts may be obtained from ammonium carbonate and the corresponding acids. Saturated solutions may be prepared from these salts and the crystal I grown from watery solutions at a gradually decreasing temperture in any suitable manner.
  • the crystal shapeillustrated in Fig. 1 may be varied somewhat to obtain either needle-shaped crystals, or the more compact or short prism form as illustratedin Fig. l.
  • Ammonium dihydrogen phosphate produces short and thick prismatic crystals at room temperature. If liquor is added in excess, all of these salts may be crystallized in short prisms at room temperature.
  • the short thick form of crystal l, as illustrated in Fig. 1, is generally the more convenient form for cutting the various orientations of crystal plates therefrom.
  • Fig. 2 is a diagram illustrating the system, recently defined by the Institute of Radio Engineers, for specifying the orientation for a piezoelectric crystal element or body 2 in relation to its mutually perpendicular X, Y and Z axes.
  • the X axis is taken along the length dimension L of the crystal element 2
  • the Y axis is taken along the width dimension W of the crystal element 2
  • the Z axis is taken along the thickness or thin dimension T of the crystal element 2.
  • the angle 0 is, as shown in Fig.
  • the angle between the optic axis Z and the plate normal or Z axis, and the angle q) is the angle between the +X axis by tension) and the intersection of the plane containing the Z and Z axes with the XY plane, while it is the angle between the length L axis X and the tangent of the great circle containing the Z and Z axes as measured in a plane perpendicular to the Z axis. All angles are positive when measured in a counterclockwise direction.
  • Fig. 2 is applicable to a right-hand crystal, such as quartz, following the crystallographers definition and the earlier Biot convention.
  • the positive X axis is the X axis for which a positive charge develops on a tension stress bein applied thereto.
  • the crystal element 2 of Fig. 2 may be cut from any of the crystalline phosphate and arsenate substances illustrated in Fig. l, and, by specifying the values for the three angles 0, q: and t of Fig. 2 may generally designate the orientation of any of the several crystal elements disclosed in this specification and illustrated in Figs. 3 to 5 of the drawing.
  • Suitable conductive electrodes such as the crystal electrodes 3 and 4 of Fig. 2 may be placed on or adjacent to or formed integral with the opposite major faces of any of the crystal plates disclosed herein in order to apply electric field excitation thereto.
  • the crystal electrodes 3 and 4 when formed integral with the surfaces of any of the crystal elements 2 may consist of gold, platinum, aluminum, silver or other suitable conductive material deposited upon the crystal surfaces by evaporation in vacuum, painting, spraying, or by other suitable process. If desired, the crystal element 2 may be electroplated to the desired frequency by nickel plating or otherwise.
  • the thickness shear mode crystal elements illustrated in Figs. 3 to 5 may be utilized at the relatively high thickness mode frequencies, fundamental or harmonic, to generate high frequency waves in liquids for submarine detection and also may be used as frequency control elements in electric wave filter systems, oscillation generator systems and for other purposes where arelatively high frequency or thickness mode crystal element may be desired.
  • Figs. 3, 4 and 5 are perspective view of thickness shear mode crystal elements 30, 3
  • and 32ris' perpendicular to the other two dimensions L'a'nd W;wh'ich” may be dimensionally related to the thickness dimension T to remove spurious face mode frequencies from the region of the desired thickness 'mode'frequency.
  • and32 of Figs; 3, 4 and 5 are similar to the same typeo'f shear'motion that obtains in quartz crystals and may be similarly utilized in filter systems and oscillator systems, for example.
  • the thickness shear modes in the four isomorphic dihydrogen crystalsubstances mentioned hereinbefore are generated by the piezoelectric constants 'dg and dg, a
  • the piezoelectric constants that have the larger, values are obtained in the three orientations for the thickness shear mode crystal elements 30, 3
  • the frequency is controlled mainly by the relatively thin thickness dimension T, and the major faces thereof may be of square or rectangular shape as illustrated in Figs. 3, 4 and 5, or of circular or othershape if desired.
  • the crystal element has one pair of its edges along or nearly along the X axis, the rectangular major faces thereof and the normal Z to the major faces being indined at an angle of 45 degrees or nearly 45 degrees with respect to the Y and Z axes, which corresponds to the orientation angles, expressed in terms of the convention illustrated in Fig. 2, of ;i;:0 degrees, 0:45 degrees and 1.11:0 degrees.
  • a v H The crystal element 3
  • anammonium' dihydrogen phosphate crystal element 3001' Fig? 3 having its width W or length L along the X axis and having its thickness axis T inclined 45" degrees from'the Z axis and having a length L, a width W and a thickness T of about 1.25, 1.25 and 0.103 centimeters, respectively, has afunda mental thickness shear mode resonant frequencyof about 1010 kilocycles per second and.
  • a"-fre'-* quency constant frof about 1040*kilccycles 'per" 75 is the second perniillimeter of thickness dimentions T for its fundamental thickness shear mode frequency, a shear elastic constant a temperature coefficient of thickness shear mode frequency of about -308 parts per million per degree centlgrade and-a temperature coeflicient of abo ut;;.666 forit-s shear elastic constant .
  • T isfthef thickness r in millimeters
  • p is'the' density which in the case of ammonium phosphate is about 1.8
  • a piezoelectric crystal element adapted for thickness shear motion at a frequency controlled mainly by its thickness dimension between its major faces, and comprising one of the substances ammonium dihydrogen phosphate, potassium dihydrogen phosphate, potassium dihydrogen arsenate and ammonium dihydrogen arsenate, said major faces being substantially parallel to one of the three mutually perpendicular X, Y and Z axes and inclined at the bisecting angle of substantially 45 degrees with respect to the other two of said three X, Y and Z axes of said crystal element, said angle being a value corresponding to substantially the largest value of piezoelectric constant in said crystal substance for said thickness shear mode of motion.
  • a piezoelectric crystal element adapted for 10 thickness shear motionata frequency controlled mainly. by its thickness. dimension between its major. faces, and comprising one of the substances ammonium dihydrogen phosphate, potassium dihydrogen ,phosphate, potassium dihydrogen arsenate and ammonium dihydrogen arsenate, said majoryfaces being substantially parallel :to one of the three mutually perpendicular X, Y and Z axes and inclinedat the bi-secting angle of substantially. 45 .degrees with respect to the other two of saidlthree X, Y andZaxes of. said crystal element, said angle being a value corresponding to substantially the largest value of. piezoelectric constantin saidcrystal substance for said thickness shear mode of motion, and means comprising electrodes cooperating with said major faces for operating said crystal element in said thicknessshear mode ofmotion.
  • Piezoelectric crystal apparatus in accordance with claim 4 wherein said major faces are substantially parallel to said Y axis, and said bisecting angle is inclined substantially 45 degrees Withrespect :tosaid' X and. Z axes and corresponds to a value where said thickness shear mode of motion has a high electromechanical coupling value, and said one of said substances is ammonium dihydrogen phosphate.
  • a piezoelectric crystal element adapted for thickness shear motion at a frequency controlled mainly by its thickness axis dimension between its major faces, and comprising one of the substances ammonium dihydrogen phosphate, potassium dihydrogen phosphate, potassium dihydrogen arsenate and ammonium dihydrogen arsenate, said major faces being substantially parallel to the Z axis of the three mutually perpendicular X, Y and Z axes and inclined at the bisecting angle of substantially 45 degrees with respect to the other two X and Y axes of said three X, Y and Z axes of said crystal element, said angle being a value corresponding to substantially the largest value of piezoelectric constant in said crystal substance for said thickness shear mode of motion, and said angle being a value corresponding to a substantially zero value of coupling of said thickness shear motion with the face shear mode of motion in said major faces, said thickness dimension being a value corresponding to the value of said frequency for said thickness shear mode of motion, and means comprising electrodes cooper
  • Piezoelectric apparatus in accordance with claim 6 wherein said one of said substances is ammonium dihydrogen phosphate.
  • a piezoelectric crystal element adapted for thickness shear motion at a frequency controlled mainly by its thickness axis dimension between its major faces, and comprising one of the substances ammonium dihydrogen phosphate, potassium dihydrogen phosphate, potassium dihydrogen arsenate and ammoninum dihydrogen arsenate, said major faces being substantially parallel to the Z axis of the three mutually perpendicular X, Y and Z axes and inclined at the bisecting angle of substantially 45 degrees with respect to the other two X and Y axes of said three X, Y and Z axes of said crystal element, said angle being a value corresponding to substantially the largest value of piezoelectric constant in said crystal substance for said thickness shear mode of motion, and said angle being a value corresponding to a substantially zero value of coupling of said thickness shear motion with the face shear 11 mode of motion in'said major faces; said thick ness dimension being avalue corresponding to the value of said frequency for said thickness shear mode of motion.
  • a piezoelectric crystal element adapted for thickness shear motion at a frequency controlled mainly by its thickness axis dimension between its major faces, and comprising one of the substances ammonium dihydrogen phosphate, p0- tassium dihydrogen phosphate, potassium dihydrogen arsenate and ammonium dihydrogen arsenate, said major faces being substantially parallel to the Z axis of the three mutually perpendicular X, Y and Z axes and inclined at the bisecting angle of substantially 45 degrees with respect to the other two'X- and Y axes of said three X, Y and Z axes of said crystal element, said angle being a value corresponding to substantially the largest value of piezoelectric'constant in said crystal substance for said thickness shear mode of motion, and said angle being a value corresponding to a substantially zero value of coupling of said thickness shear motion REFERENCES CITED
  • the following references are of record in the file of this patent:

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
US637127A 1943-08-09 1945-12-24 Piezoelectric crystal apparatus Expired - Lifetime US2484635A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
BE472576D BE472576A (d) 1943-08-09
US637127A US2484635A (en) 1943-08-09 1945-12-24 Piezoelectric crystal apparatus
US637126A US2450011A (en) 1943-08-09 1945-12-24 Piezoelectric crystal apparatus
GB34524/46A GB641469A (en) 1943-08-09 1946-11-21 Improved piezoelectric crystals
FR938529D FR938529A (fr) 1943-08-09 1946-12-17 Cristaux piézoélectriques
GB37773/46A GB641471A (en) 1943-08-09 1946-12-23 Piezoelectric crystal elements
GB37772/46A GB641470A (en) 1943-08-09 1946-12-23 Piezoelectric crystal elements

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US497883A US2450010A (en) 1943-08-09 1943-08-09 Piezoelectric crystal apparatus
US637127A US2484635A (en) 1943-08-09 1945-12-24 Piezoelectric crystal apparatus

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US2484635A true US2484635A (en) 1949-10-11

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2680720A (en) * 1944-06-08 1954-06-08 Clevite Corp Piezoelectric crystal body comprised of rubidium compound
US3072806A (en) * 1961-07-05 1963-01-08 Leland T Sogn Quartz piezoelectric element
US3461408A (en) * 1967-02-09 1969-08-12 Bell Telephone Labor Inc Oriented litao3 crystal and devices using same
US3694676A (en) * 1971-03-17 1972-09-26 Zenith Radio Corp Shear mode piezoelectric filter

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1086630B (it) * 1976-03-19 1985-05-28 Pentel Kk Punta per penna a sfera e procedimento di produzione

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2303375A (en) * 1941-06-10 1942-12-01 Bell Telephone Labor Inc Rochelle salt piezoelectric crystal apparatus
US2373445A (en) * 1943-01-18 1945-04-10 Brush Dev Co Piezoelectric device
GB569285A (en) * 1942-11-21 1945-05-16 Patelhold Patentverwertung Piezo-electric device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2303375A (en) * 1941-06-10 1942-12-01 Bell Telephone Labor Inc Rochelle salt piezoelectric crystal apparatus
GB569285A (en) * 1942-11-21 1945-05-16 Patelhold Patentverwertung Piezo-electric device
US2373445A (en) * 1943-01-18 1945-04-10 Brush Dev Co Piezoelectric device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2680720A (en) * 1944-06-08 1954-06-08 Clevite Corp Piezoelectric crystal body comprised of rubidium compound
US3072806A (en) * 1961-07-05 1963-01-08 Leland T Sogn Quartz piezoelectric element
US3461408A (en) * 1967-02-09 1969-08-12 Bell Telephone Labor Inc Oriented litao3 crystal and devices using same
US3694676A (en) * 1971-03-17 1972-09-26 Zenith Radio Corp Shear mode piezoelectric filter

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GB641469A (en) 1950-08-16
GB641470A (en) 1950-08-16
FR938529A (fr) 1948-10-18
GB641471A (en) 1950-08-16
BE472576A (d)

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