US3699482A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surface waveguiding in ceramics by selective poling
Assignee: International Business Machines Corp
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Filing: 1971-06-30
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Granted: 1972-10-17
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Expires: 1991-06-30
Abstract
Abstract A surface waveguide structure and method of making same. A substrate material consisting either of a piezoelectric ceramic or ferroelectric crystal, is selectively poled by an electric field so as to form an elastic surface wave channel within the substrate structure. The electric field applied cross the substrate causes a polarization of the crystalline structure in those areas influenced by the electric field and has a negligible effect in those areas not exposed to the electric field. The free surface wave velocity is substantially increased in the polarized areas of the substrate and remains unchanged in the unpolarized regions. Poling of the substrate is accomplished by applying an electric field across a pair of electrodes which cover the upper and lower surfaces of the substrate except for a narrow region between the transmitting and receiving surface wave transducers. The process for manufacturing the surface waveguide structure is applicable to both acoustic and optical surface waveguiding devices. Also, the polarization of the substrate may be selectively altered by subsequent application of electric fields across the body of the substrate to make switchable waveguide regions.
Inventors
- 👤 Eric A Ash
- 👤 Samuel C-C Tseng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:07
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/74; H03H9/76; H03H9/02; H03H9/02535; H03H9/02543; H03H9/30; H03H9/42
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
129 words
A surface waveguide device comprising: a substrate material capable of supporting an elastic surface wave; input transducer means positioned on said substrate for receiving an electrical input pulse train and in response thereto launch an elastic surface wave on the surface of said substrate; output transducer means positioned on said substrate for receiving said surface wave and converting the wave energy to an electrical pulse; said input and output transducer means being positioned opposite each other and separated by a finite distance over which said surface wave travels; said substrate having two regions; a first region being polarized to an orientation that increases the phase velocity of surface waves; and a second narrow guide region which is unpolarized and forms a connecting path between said input and output transducers.
Claim 2
Dependent Claim
129 words
A surface waveguide device comprising: a substrate material capable of supporting an elastic surface wave; input transducer means positioned on said substrate for receiving an electrical input pulse train and in response thereto launch an elastic surface wave on the surface of said substrate; output transducer means positioned on said substrate for receiving said surface wave and converting the wave energy to an electrical pulse; said input and output transducer means being positioned opposite each other and separated by a finite distance over which said surface wave travels; said substrate having two regions; a first region being polarized to an orientation that increases the phase velocity of surface waves; and a second narrow guide region which is unpolarized and forms a connecting path between said input and output transducers.
Claim 3
Dependent Claim
14 words
The device specified in claim 1 wherein said substrate is a piezoelectric ceramic material.
Claim 4
Dependent Claim
13 words
The device as specified in claim 2 wherein said piezoelectric material is PZT.
Claim 5
Dependent Claim
14 words
The device as specified in claim 1 wherein said substrate is a ferroelectric crystal.
Claim 6
Dependent Claim
16 words
The device aS specified in claim 1 wherein said input and output transducers are interdigital transducers.
Claim 7
Dependent Claim
20 words
The device as specified in claim 1 wherein said polarized region of said substrate is a piezoelectrically stiffened elastic material.
Claim 8
Independent Claim
95 words
A method for making a surface waveguide device comprising the steps of: preparing a substrate material capable of supporting elastic wave energy for further deposition steps; depositing upper and lower electrode layers on the upper and lower surface of said substrate; removing a narrow region from the upper electrode layer so as to expose a narrow guide channel between said input and output transducers; applying a potential differential between said upper and lower electrode layers for a sufficient length of time to polarize those areas in the substrate that are sandwiched between the two electrodes.
Claim 9
Independent Claim
95 words
A method for making a surface waveguide device comprising the steps of: preparing a substrate material capable of supporting elastic wave energy for further deposition steps; depositing upper and lower electrode layers on the upper and lower surface of said substrate; removing a narrow region from the upper electrode layer so as to expose a narrow guide channel between said input and output transducers; applying a potential differential between said upper and lower electrode layers for a sufficient length of time to polarize those areas in the substrate that are sandwiched between the two electrodes.
Claim 10
Dependent Claim
35 words
The method as defined in claim 7 further comprising the steps of: selectively removing said upper electrode layer so as to form an input and output transducer on said substrate; removing said lower electrode layer.
Claim 11
Dependent Claim
45 words
The process as defined in claims 7 further comprising the steps of: applying a heat environment to said substrate prior to the application of a potential differential between said electrode layers; and continuing the application of voltage gradient until said substrate cools to room temperature.
Claim 12
Dependent Claim
22 words
The method as defined in claim 9 wherein said potential differential is applied for a time sufficient to polarize said substrate material.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-17 | 1976-04-17 | 1976-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-17 | 1980-04-17 | 1980-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-17 | 1984-04-17 | 1984-10-17 | $7700.00 | Window Closed / Lapsed |