초록 ▼

A ceramic filter including a piezoelectric ceramic and input and output electrode groups disposed within the ceramic body. The input electrode group and the output electrode group extend toward each other from opposing sides of the piezoelectric ceramic. They do not meet, however, and a predetermine

A ceramic filter including a piezoelectric ceramic and input and output electrode groups disposed within the ceramic body. The input electrode group and the output electrode group extend toward each other from opposing sides of the piezoelectric ceramic. They do not meet, however, and a predetermined spacing, along the thickness dimension of the ceramic, separates the two electrode groups. The input and output electrode groups are each composed of a plurality of electrodes which overlap each other with ceramic layers interposed therebetween.

대표청구항 ▼

A ceramic filter comprising: a multi-layered piezoelectric ceramic body including a plurality of stacked ceramic sheets, said ceramic body having a thickness extending through said plurality of stacked sheets and first and second opposite ends separated along said thickness, said ceramic being polar

A ceramic filter comprising: a multi-layered piezoelectric ceramic body including a plurality of stacked ceramic sheets, said ceramic body having a thickness extending through said plurality of stacked sheets and first and second opposite ends separated along said thickness, said ceramic being polarized in one direction along a direction corresponding to said thickness; bulk wave eliminating means for eliminating bulk waves which produce spurious vibrations other than utilizable bulk waves located at, at least one of said first and second ends of said ceramic; an input electrode group including a plurality of internal input electrodes, at least one electrode being formed on each sheet of a selected group of said sheets lying adjacent said first end of said ceramic body, adjacent ones of said input electrodes overlapping each other along said thickness of said ceramic body; an output electrode group including a plurality of internal output electrodes, at least one electrode being formed on each sheet of a selected group of said sheets lying adjacent said second end of said ceramic body, adjacent ones of said output electrodes overlapping each other along said thickness of said ceramic body, said input and output groups overlapping each other along said thickness and being spaced a predetermined distance apart, alternate internal electrodes which follow one another in each said input and output electrode groups being led out to respective first and second lateral sides of said piezoelectric ceramic; a first pair of external electrodes having first and second external contacts for contacting, respectively, said input internal electrodes which are led out at said first and second lateral sides, and a second pair of external electrodes having first and second external contacts for contacting, respectively, said output internal electrodes which are led out at said first and second sides; and means for applying a voltage to at least one of said input electrodes and producing an output at said output electrode group in response to vibrations which propagate from said input group to said output group.