Piezoelectric vibrator with damping electrodes

Claim 2

A piezoelectric vibrator of the energy trapping type which operates in the thickness vibrational mode, comprising: an elongated ceramic piezoelectric plate having first and second opposed planar surfaces, and having opposite pairs of lengthwise and widthwise edges; a first electrode deposited approximately at a center portion on said first planar surface of said piezoelectric plate; a second electrode deposited approximately at a center portion on said second planar surface of said piezoelectric plate in face-to-face relation with said first electrode, said first and second electrodes adapted to receive an electrical signal which will cause said piezoelectric plate to vibrate primarily in the thickness vibrational mode; first damping means comprising a third electrode located along the entirety of a first one of said widthwise edges and a damping material deposited entirely along said third electrode; second damping means comprising a fourth electrode located along the entirety of said second widthwise edges and a damping material deposited entirely along said fourth electrode; the distance G between that edge of said first electrode which is closest to one of said lengthwise edges of said piezoelectric plate and said one of said lengthwise edges of said piezoelectric plate, and the thickness T of the piezoelectric plate as measured between said planar surfaces satisfying the relationship 0≦G/T≦15; and said first and third electrodes being electrically connected to each other and said second and fourth electrodes being electrically connected to each other.

Claim 3

A piezoelectric vibrator as claimed in claim 1, wherein said damping material is solder bead.

Claim 4

A piezoelectric oscillator as claimed in claim 1, wherein said damping material is an electrically conductive bonding agent.

Claim 5

A piezoelectric vibrator as claimed in claim 1, further comprising a first terminal leg extending from said third electrode.

Claim 6

A piezoelectric vibrator as claimed in claim 1, further comprising a second terminal leg extending from said fourth electrode.

Claim 7

A piezoelectric vibrator of energy trapped type which operates in the thickness vibrational mode, comprising: an elongated ceramic piezoelectric plate having first and second half portions on respective sides of an imaginary center line drawn in the widthwise direction of said elongated piezoelectric plate at a position intermediate of the length of said piezoelectric plate, said plate having first and second opposed planar surfaces and opposite pairs of lengthwise and widthwise edges; a first electrode deposited approximately at a center portion of said first half portion and on said first planar surface of the piezoelectric plate; a second electrode deposited approximately at a center portion of said first half portion and on said second planar surface of said piezoelectric plate in face-to-face relation with said first electrode, said first and second electrodes adapted to receive an electrical signal which causes said elongated piezoelectric plate to vibrate primarily in the thickness mode; a third electrode deposited approximately at a center portion of said second half portion and on said first planar surface of said piezoelectric plate; a fourth electrode deposited approximately at a center portion of said second half portion and on said second planar surface of said piezoelectric plate in face-to-face relation with said third electrode, said third and fourth electrodes adapted to receive an electrical signal that causes said elongated piezoelectric plate to vibrate primarily in the thickness vibration mode; the minimum distance G between the edge of each of the first and third electrodes and the edge of said lengthwise edges of said elongated piezoelectric plate, and the thickness T as measured between said planar surfaces of said piezoelectric plate satisfies the following relation: 0≦G/T≦15; first damping means located at said first widthwise edge of said elongated piezoelectric plate along the entire edge thereof; second damping means located at said second widthwise edge of said elongated piezoelectric plate along the entire edge thereof; and third damping means applied at a center portion of said elongated piezoelectric plate along said center line.

Claim 8

A piezoelectric vibrator of energy trapped type which operates in the thickness vibrational mode, comprising: an elongated ceramic piezoelectric plate having first and second half portions on respective sides of an imaginary center line drawn in the widthwise direction of said elongated piezoelectric plate at a position intermediate of the length of said piezoelectric plate, said plate having first and second opposed planar surfaces and opposite pairs of lengthwise and widthwise edges; a first electrode deposited approximately at a center portion of said first half portion and on said first planar surface of the piezoelectric plate; a second electrode deposited approximately at a center portion of said first half portion and on said second planar surface of said piezoelectric plate in face-to-face relation with said first electrode, said first and second electrodes adapted to receive an electrical signal which causes said elongated piezoelectric plate to vibrate primarily in the thickness mode; a third electrode deposited approximately at a center portion of said second half portion and on said first planar surface of said piezoelectric plate; a fourth electrode deposited approximately at a center portion of said second half portion and on said second planar surface of said piezoelectric plate in face-to-face relation with said third electrode, said third and fourth electrodes adapted to receive an electrical signal that causes said elongated piezoelectric plate to vibrate primarily in the thickness vibration mode; the minimum distance G between the edge of each of the first and third electrodes and the edge of said lengthwise edges of said elongated piezoelectric plate, and the thickness T as measured between said planar surfaces of said piezoelectric plate satisfies the following relation: 0≦G/T≦15; first damping means located at said first widthwise edge of said elongated piezoelectric plate along the entire edge thereof; second damping means located at said second widthwise edge of said elongated piezoelectric plate along the entire edge thereof; and third damping means applied at a center portion of said elongated piezoelectric plate along said center line.

Claim 9

A piezoelectric vibrator as claimed in claim 6, wherein said first damping means comprises: a fifth electrode deposited at said first widthwise edge of said elongated piezoelectric plate along the entire edge thereof, and a damping material deposited entirely on said fifth electrode.

Claim 10

A piezoelectric vibrator as claimed in claim 7, wherein said second damping means comprises: a sixth electrode deposited at said second widthwise edge of said elongated piezoelectric plate along the entire edge thereof, and a damping material deposited entirely on said sixth electrode.

Claim 11

A piezoelectric vibrator as claimed in claim 8, wherein said third damping means comprises: a seventh electrode deposited at said center portion of said elongated piezoelectric plate along said center line and on said second surface of said piezoelectric plate, and a damping material deposited entirely on said seventh electrode.

Claim 12

A piezoelectric vibrator as claimed in claim 7, 8 or 9, wherein said damping material is a solder bead.

Claim 13

A piezoelectric vibrator as claimed in claim 7, 8 or 9, wherein said damping material is an electrically conductive bonding agent.

Claim 14

A piezoelectric vibrator as claimed in claim 9, wherein each of said first and third electrodes includes two separate electrode segments which are located in side-by-side relation to each other.

Claim 15

A piezoelectric vibrator as claimed in claim 12, further comprising an intervening electrode deposited on said first planar surface of said piezoelectric plate, said intervening electrode extending between one separate electrode segment of said first electrode and one separate electrode segment of said second electrode.

Claim 16

A piezoelectric vibrator as claimed in claim 13, wherein the other separate electrode segment of the first electrode is connected to the fifth electrode and the other separate electrode segment of the second electrode is connected to the sixth electrode.

Claim 17

A piezoelectric vibrator as claimed in claim 14, further comprising an eighth electrode located on said first planar surface of said piezoelectric plate in face-to-face relation with said seventh electrode for establishing a capacitor element between said seventh and either electrodes, said eighth electrode being connected to said intervening electrode.

Claim 18

A piezoelectric vibrator as claimed in claim 14, further comprising first, second and third terminal legs connected to the fifth, sixth and seventh electrodes, respectively.

Claim 19

A piezoelectric vibrator as claimed in claim 16, further comprising first and second guard plates sandwiching the piezoelectric plate.