Shear mode transducer for drop-on-demand liquid ejector

Claim 2

In a pressure pulse droplet ejector: a fluid pressure chamber housing having a portion thereof forming an opening into said chamber, means extending across said opening to form a deformable wall of said chamber, said means comprising a piezoelectric transducer, the portion of said piezoelectric transducer which is adjacent the perimeter of said portion of said fluid pressure chamber forming said opening being restrained against movement relative to said housing, said piezoelectric transducer having a polarized portion which is free for reciprocal deformation relative to said housing in the general direction of polarization, the direction of polarization being generally transverse to the direction in which said piezoelectric transducer extends across said opening, means for applying an electrical field to said polarized portion substantially orthogonal to the polarization field to cause said polarized portion to deform in shear in the general direction of polarization to vary the volume of said chamber.

Claim 3

The structure as recited in claim 1 wherein said means for applying said electrical field comprises: first electrode means and second electrode means, means for applying a potential of a first magnitude to said first electrode means, and means for applying a potential of a second magnitude to said second electrode means, said first and second electrode means being spaced from each other in a manner to create an electrical field substantially orthogonal to the polarization field when said potentials are applied thereto.

Claim 4

The structure as recited in claim 1 wherein said means for applying said electrical field comprises: first electrode means and second electrode means being generally in the same plane as said first electrode means and being laterally spaced from and surrounding at least a portion of said first electrode means, means for applying a potential of a first magnitude to said first electrode means, and means for applying a potential of a second magnitude to said second electrode means, whereby an electrical field substantially orthogonal to the polarization field is created.

Claim 5

The structure as recited in claim 3 wherein said first electrode means is attached to said polarized portion of said piezoelectric transducer.

Claim 6

The structure as recited in claim 3 wherein said first electrode means is completely surrounded by said second electrode means.

Claim 7

The structure as recited in claim 1, wherein said means for applying said electrical field comprises: first electrode means and second electrode means at one level of the piezoelectric transducer, said second electrode means being laterally spaced from and surrounding at least a portion of said first electrode means, third electrode means and fourth electrode means at a second level of the piezoelectric transducer, said fourth electrode means being laterally spaced from and surrounding at least a portion of said third electrode means, said first and third electrode means being generally coextensive and aligned with each other, said second and fourth electrode means being generally coextensive and aligned with each other, means for applying a potential of a first magnitude to said first and third electrode means, and means for applying a potential of a second magnitude to said second and fourth electrode means, whereby an electrical field substantially orthogonal to the polarization field is created by the potentials applied to said first and second electrode means and by the potentials applied to said third and fourth electrode means.

Claim 8

The structure as recited in claim 6 wherein said one level is on one surface of the piezoelectric transducer and said second level is on the opposite surface of the piezoelectric transducer.

Claim 9

The structure as recited in either of claims 6 or 7 wherein said piezoelectric transducer is a generally flat member.

Claim 10

The structure as recited in claim 6 wherein said means for applying a potential of said magnitude to said third electrode means is by high capacitance coupling with said first electrode means.

Claim 11

The structure as recited in either of claims 6 or 9 wherein said means for applying a potential of said second magnitude to said fourth electrode means is by high capacitance coupling with said second electrode means.

Claim 12

In a pressure pulse droplet ejector: a housing containing at least two fluid pressure chambers, said housing having a portion thereof forming an opening into each said chamber, means extending across said openings of said chambers to form a deformable wall of each of said chambers, said means comprising a piezoelectric transducer, the portion of said piezoelectric transducer which is adjacent the perimeter of said portion of a respective said fluid pressure chamber forming said opening being restrained against movement relative to said housing, said piezoelectric transducer having first and second polarized portions, one for each chamber, which are free for reciprocal deformation relative to said housing in the general direction of polarization, the direction being generally transverse to the direction in which said piezoelectric transducer extends across said openings, first means for applying an electrical field to said first polarized portion substantally orthogonal to the polarization field to cause said first polarized portion to deform in shear in the general direction of polarization to vary the volume of its respective chamber, and second means for applying an electrical field, independently of the electrical field applied to said first portion, to said second polarized portion substantially orthogonal to the polarization field to cause said second polarized portion to deform in shear in the general direction of polarization to vary the volume of its respective chamber chambers.

Claim 13

In a pressure pulse droplet ejector: a housing containing at least two fluid pressure chambers, said housing having a portion thereof forming an opening into each said chamber, means extending across said openings of said chambers to form a deformable wall of each of said chambers, said means comprising a piezoelectric transducer, the portion of said piezoelectric transducer which is adjacent the perimeter of said portion of a respective said fluid pressure chamber forming said opening being restrained against movement relative to said housing, said piezoelectric transducer having first and second polarized portions, one for each chamber, which are free for reciprocal deformation relative to said housing in the general direction of polarization, the direction being generally transverse to the direction in which said piezoelectric transducer extends across said openings, first means for applying an electrical field to said first polarized portion substantally orthogonal to the polarization field to cause said first polarized portion to deform in shear in the general direction of polarization to vary the volume of its respective chamber, and second means for applying an electrical field, independently of the electrical field applied to said first portion, to said second polarized portion substantially orthogonal to the polarization field to cause said second polarized portion to deform in shear in the general direction of polarization to vary the volume of its respective chamber chambers.

Claim 14

The structure as recited in claim 11 wherein: said first means for applying said electrical field comprises first electrode means and electrode means spaced from said first electrode means, said second means for applying said electrical field comprises second electrode means and electrode means spaced from said second electrode means, said first means for applying said electrical field further comprises means for applying a potential of a first magnitude to said first electrode means and means for applying a potential of a second magnitude to said electrode means spaced from said first electrode means, said second means for applying said electrical field further comprises means for applying a potential of said first magnitude to said second electrode means and means for applying a potential of said second magnitude to said electrode means spaced from said second electrode means, said first electrode means and said electrode means spaced therefrom being spaced in such a manner to create an electrical field substantially orthogonal to the polarization field of said first portion when said potentials are applied thereto, said second electrode means and said electrode means spaced therefrom being spaced in such a manner to create an electrical field substantially orthogonal to the polarization field of said second portion when said potentials are applied thereto.

Claim 15

The structure as recited in claim 11 wherein: said first means for applying said electrical field comprises first electrode means and electrode means being generally in the same plane as said first electrode means and laterally spaced from and surrounding at least a portion of said first electrode means, said second means for applying said electrical field comprises second electrode means and electrode means being generally in the same plane as said second electrode means and laterally spaced from and surrounding at least a portion of said second electrode means, said first means for applying said electrical field further comprises means for applying a potential of a first magnitude to said first electrode means and means for applying a potential of a second magnitude to said electrode means surrounding at least a portion of said first electrode means, said second means for applying said electrical field further comprises means for applying a potential of said first magnitude to said second electrode means and means for applying a potential of said second magnitude to said electrode means surrounding at least a portion of said second electrode means, whereby an electrical field substantially orthogonal to said polarization field of said first portion of said piezoelectric transducer is created by the potentials applied to said first electrode means and said electrode means surrounding at least a portion thereof and an electrical field substantially orthogonal to said polarization field of said second portion of said piezoelectric transducer is created by the potentials applied to said second electrode means and said electrode means surrounding at least a portion thereof.

Claim 16

The structure as recited in either claims 13 wherein each of said fluid pressure chambers have an open end bridged by said piezoelectric transducer, said first portion of said piezoelectric transducer bridges said one chamber, said second portion of said piezoelectric transducer bridges said other chamber, said first electrode means is attached to said first portion of said piezoelectric transducer and said second electrode means is attached to said second portion of said piezoelectric transducer.

Claim 17

The structure as recited in claim 13 wherein said first and second electrode means are completely surrounded by said third electrode means.

Claim 18

The structure as recited in claim 11 wherein: said first means for applying said electrical field comprises first electrode means at one level of said piezoelectric transducer and electrode means at said one level laterally spaced from and surrounding at least a portion of said first electrode means; second electrode means at a second level of said piezoelectric transducer and electrode means at said second level laterally spaced from and surrounding at least a portion of said second electrode means; said second electrode means and said electrode means surrounding at least a portion of said second electrode means being generally coextensive and aligned with said first electrode means and said electrode means surrounding at least a portion of said first electrode means, respectively; said second means for applying said electrical field comprises third electrode means at said one level of said piezoelectric transducer and electrode means at said one level laterally spaced from and surrounding at least a portion of said third electrode means; fourth electrode means at said second level of said piezoelectric transducer and electrode means at said second level laterally spaced from and surrounding at least a portion of said fourth electrode means, said fourth electrode means and said electrode means surrounding at least a portion of said fourth electrode means being generally coextensive and aligned with said third electrode means and said electrode means surrounding at least a portion of said third electrode means, respectively; said first means for applying said electrical field further comprises means for applying a potential of a first magnitude to said first and second electrode means and means for applying a potential of a second magnitude to said electrode means surrounding at least a portion of said first electrode means and to said electrode means surrounding at least a portion of said second electrode means; said second means for applying said electrical field further comprises means for applying a potential of said first magnitude to said third and fourth electrode means and means for applying a potential of said second magnitude to said electrode means surrounding at least a portion of said third electrode means and to said electrode means surrounding at least a portion of said fourth electrode means; whereby an electrical field substantially orthogonal to said polarization field of said first portion of said piezoelectric transducer is created by the potentials applied to said first electrode means and said electrode means surrounding at least a portion thereof and by the potentials applied to said second electrode means and said electrode means surrounding at least a portion thereof and an electrical field substantially orthogonal to said polarization field of said second portion of said piezoelectric transducer is created by the potentials applied to said third electrode means and said electrode means surrounding at least a portion thereof and by the potentials applied to said fourth electrode means and said electrode means surrounding at least a portion thereof.

Claim 19

The structure as recited in either of claims 16 wherein said first and second electrode means is attached to said first polarized portion of said piezoelectric transducer, and said third and fourth electrode means is attached to said second polarized portion of said piezoelectric transducer

Claim 20

The structure as recited in either of claims 16 or 17 wherein said one level is on one surface of the piezoelectric transducer and said second level is on the opposite surface of the piezoelectric transducer.

Claim 21

The structure as recited in either of claims 16 or 17 wherein said piezoelectric transducer is generally a flat member and said one level is on one surface of the piezoelectric transducer and said second level is on the opposite surface of the piezoelectric transducer.

Claim 22

The structure as recited in claim 11 wherein: said first means for applying said electrical field comprises first electrode means, said second means for applying said electrical field comprises second electrode means, said first electrode means being laterally spaced from and generally in the same plane as said second electrode means, said first and second means for applying said electrical field further comprises third electrode means being generally in the same plane as said first and second electrode means, said third electrode means being laterally spaced from and surrounding at least a portion of each of said first and second electrode means, said first means for applying said electrical field further comprises means for applying a potential of a first magnitude to said first electrode means and means for applying a potential of a second magnitude to said third electrode means, said second means for applying said electrical field further comprises means for applying a potential of said first magnitude to said second electrode means, and said means for applying a potential of said second magnitude to said third electrode means, whereby an electrical field substantially orthogonal to said polarization field of said first portion of said piezoelectric transducer is created by the potentials applied to said first electrode means and said third electrode means and an electrical field substantially orthogonal to said polarization field of said second portion of said piezoelectric transducer is created by the potentials applied to said second electrode means and said third electrode means.

Claim 23

The structure as recited in claim 7 wherein: said first means for applying said electrical field comprises first electrode means at one level of said piezoelectric transducer and second electrode means at a second level of said piezoelectric transducer being generally coextensive and aligned with said first electrode means, said second means for applying said electrical field comprises third electrode means at said one level of said piezoelectric transducer and laterally spaced from said first electrode means and fourth electrode means at said second level of said piezoelectric transducer being generally coextensive and aligned with said third electrode means, said first and second means for applying said electrical field further comprises fifth electrode means at said one level and laterally spaced from and surrounding at least a portion of each of said first and third electrode means and sixth electrode means at said second level of said piezoelectric transducer being generally coextensive and aligned with said fifth electrode means, said first means for applying said electrical field further comprises means for applying a potential of a first magnitude to said first and second electrode means and means for applying a potential of a second magnitude to said fifth and sixth electrode means, said second means for applying said electrical field further comprises means for applying a potential of said first magnitude to said third and fourth electrode means and means for applying a potential of said second magnitude to said fifth and sixth electrode means, whereby an electrical field substantially orthogonal to said polarization field of said first portion of said piezoelectric transducer is created by the potentials applied to said first and fifth electrode means and by the potentials applied to said second and sixth electrode means and an electrical field substantially orthogonal to said polarization field of said second portion of said piezoelectric transducer is created by the potentials applied to said third and fifth electrode means and by the potentials applied to said fourth and sixth electrode means.

Claim 24

The structure as recited in claim 21 wherein said means for applying a potential of said first magnitude to said fourth electrode means is by high capacitance coupling with said second electrode means.

Claim 25

The structure as recited in either of claims 21 or 22 wherein said means for applying a potential of said first magnitude to said fourth electrode means is by high capacitance coupling with said third electrode means.

Claim 26

The structure as recited in either of claims 21 or 22 wherein said means for applying a potential of said second magnitude to said sixth electrode means is by high capacitance coupling with said fifth electrode means.

Claim 27

The structure as recited in claim 24 wherein said means for applying a potential of said first magnitude to said fourth electrode means is by high capacitance coupling with said third electrode means and said means for applying a potential of said second magnitude to said sixth electrode means is by high capacitance coupling with said fifth electrode means.

Claim 28

The structure as recited in claim 25 wherein said means for applying a potential of said first magnitude to said second electrode means is by high capacitance coupling with said first electrode means.