Method of manufacturing a monolithic crystal filter
US4112147A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 13, 1977 |
| Grant date | Sep 5, 1978 |
| Priority date | — |
| Expiry date | May 13, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/42
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A method of manufacturing a monolithic crystal filter, and particularly a filter having a high midband frequency (e.g., 20 MHz or above) and a wide resonator coupling (e.g., 4 KHz or above), involves the plating of additional electrode material onto a pair of base-plated split electrodes on one side of a crystal wafer to establish a desired coupling between resonators of the filter. Additional electrode material then is plated onto a base-plated solid electrode on the opposite side of the crystal wafer to establish a desired midband frequency of the filter. When the electrodes are plated in this sequence, the resonator coupling decreases substantially during the additional plating of the split electrodes, but remains essentially constant, within tolerance limits, during the plating of the solid electrode, whereby further adjustment of the coupling is not necessary.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.