US4103264A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wave filter and process for making same
Assignee: Vernitron Corp
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Filing: 1976-01-30
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Granted: 1978-07-25
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Expires: 1996-01-30
Abstract
Abstract In the manufacture of wave filters, such as FM filters, polarized piezoelectrically responsive wafers are provided, temporarily, on the active regions thereof, with a removable material. Subsequent to the encapsulation of the wafer by a protective but porous coating, the filter is heated and the removable material sublimates through the porous coating establishing a wafer surface substantially free of residual impurities and leaving an uninterrupted cavity between the wafer and the coating in the active regions. The preferred sublimatable material is paradichlorobenzene.
Inventors
- 👤 Glenn N. Howatt
- 👤 Murray Leonard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:00
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/201; H01P1/203; H01P1/20327; H01P1/20354; H01P1/20381; Y; Y10; Y10T; Y10T29/00; Y10T29/42
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
98 words
In a process of producing electronic components such as filters, comprising the steps of providing a polarized wafer body having piezoelectrically active regions; depositing a disposable material selected from the group consisting of 1,4-dichlorobenzene and iodine on at least said active regions; subsequently applying to the wafer and on the disposable material a porous protective coating; heat treating the wafer to sublimate or evaporate said disposable material through said coating establishing a cavity between the wafer body and said coating; said disposable material being sublimatable at elevated temperatures and in a solid state at temperatures below 80° F.
Claim 2
Dependent Claim
98 words
In a process of producing electronic components such as filters, comprising the steps of providing a polarized wafer body having piezoelectrically active regions; depositing a disposable material selected from the group consisting of 1,4-dichlorobenzene and iodine on at least said active regions; subsequently applying to the wafer and on the disposable material a porous protective coating; heat treating the wafer to sublimate or evaporate said disposable material through said coating establishing a cavity between the wafer body and said coating; said disposable material being sublimatable at elevated temperatures and in a solid state at temperatures below 80° F.
Claim 3
Dependent Claim
27 words
A process as defined in claim 1, which includes the further step of applying to the resulting product a protective non-porous coating over said protective porous coating.
Claim 4
Dependent Claim
67 words
A process as defined in claim 1, wherein said protective porous coating is a composition capable of curing at elevated temperatures whereby when said coating is applied to said wafer and coats said wafer and said disposable material, and said coated wafer is heated, said protective porous material is cured or hardened while said compound or composition capable of sublimation sublimates or evaporates through said porous coating.
Claim 5
Dependent Claim
21 words
A composition as defined in claim 3, wherein said porous protective coating is a phenol-formaldehyde resin and completely encapsulates said wafer.
Claim 6
Dependent Claim
16 words
A process as defined in claim 2, wherein said protective non-porous coating is an epoxy resin.
Claim 7
Dependent Claim
35 words
A process as defined in claim 1, wherein said disposable, sublimatable material is applied to said wafer to coat from about 10% to about 60% of the total surface of said wafer with said material.
Claim 8
Dependent Claim
35 words
A process as defined in claim 1, wherein said disposable, sublimatable material is applied to said wafer to coat from about 20% to about 50% of the total surface of said wafer with said 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) | 1981-07-24 | 1982-01-23 | 1982-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-24 | 1986-01-23 | 1986-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-24 | 1990-01-23 | 1990-07-25 | $7700.00 | Window Closed / Lapsed |