Acoustic surface wave devices containing piezoelectric ceramics

Claim 2

An acoustic surface wave device comprising: a piezoelectric ceramic wafer consisting essentially of a solid solution of the ternary system Pb(Sn 1/2 Sb 1/2 ) O 3 -PbTiO 3 -PbZrO 3 having a composition showing a phase transition between a ferroelectric rhombohedral low temperature phase (F R (LT)) and a ferroelectric rhombohedral high temperature phase (F R (HT)) at a temperature within the range from -20° C. to +80° C.; and at least one electromechanical transducing means for converting an electrical signal into acoustic surface waves and vise versa, said transducing means comprising interdigital transducing electrodes coupled to a surface of said piezoelectric ceramic wafer at a transducing region thereof, said composition consisting essentially of a main component expressed by the general formula: xPb(Sn.sub.1/2 Sb.sub.1/2)O.sub.3 -yPbTiO.sub.3 -zPbZrO.sub.3 wherein, x+y+z=1.00, and an additive consisting of manganese in oxide form in an amount of 0.05 to 5.0 wt% in the form of MnO 2 , said main component having a composition in the compositional area defined by points A, B, C, D, E 1 , F 1 and G in FIG. 4, the sets of mol fractions of the three components at said points being as follows: ______________________________________ x y z ______________________________________ A 0.01 0.44 0.55 B 0.01 0.04 0.95 C 0.04 0.01 0.95 D 0.15 0.01 0.84 E.sub.1 0.25 0.01 0.74 F.sub.1 0.25 0.25 0.50 G 0.15 0.35 0.50. ______________________________________

Claim 3

An acoustic surface wave device according to claim 1, wherein said main component has a composition expressed by the formula: 0.05Pb(Sn.sub.1/2 Sb.sub.1/2)O.sub.3 -0.35PbTiO.sub.3 -0.60PbZrO.sub.3 and said additive is contained in an amount of 0.4 wt%.

Claim 4

An acoustic surface wave device according to claim 1, wherein said main component has a composition expressed by the formula: 0.05Pb(Sn.sub.1/2 Sb.sub.1/2)O.sub.3 -0.30PbTiO.sub.3 -0.65PbZrO.sub.3 and said additive is contained in an amount of 0.4 wt%.

Claim 5

An acoustic surface wave device comprising: a piezoelectric ceramic wafer consisting essentially of a solid solution of the ternary system Pb(Sn 1/2 Sb 1/2 )O 3 -PbTiO 3 -PbZrO 3 having a composition showing a phase transition between a ferroelectric rhombohedral low temperature phase (F R (LT)) and a ferroelectric rhombohedral high temperature phase (R R (HT)) at a temperature within the range from -20°0 C. to 80°; and at least one electrochemical transducing means for converting an electrical signal into acoustic surface waves and vise versa, said transducing means comprising interdigital transducing electrodes coupled to a surface of said piezoelectric ceramic wafer at a transducing region thereof, said composition consisting essentially of a main component expressed by the general formula: xPb(Sn.sub.1/2 Sb.sub.1/3)O.sub.3 -yPbTiO.sub.3 -zPbZrO.sub.3 wherein, x+y=z=1.00, and additives consisting of manganese in oxide form in an amount of 0.05 to 5.0 wt% in the form of MnO 2 and at least one element selected from the group consisting of magnesium and chromium in oxide form in respective amounts of 0.05 to 5.0 wt% in the form of MgO and Cr 2 O 3 , said main component having a composition in the compositional area defined by points A, B, C, D, E 1 , F 1 and G in FIG. 4, the sets of mol fractions of the three components at said points being as follows: ______________________________________ x y z ______________________________________ A 0.01 0.44 0.55 B 0.01 0.04 0.95 C 0.04 0.01 0.95 D 0.15 0.01 0.84 E.sub.1 0.25 0.01 0.74 F.sub.1 0.25 0.25 0.50 G 0.15 0.35 0.50. ______________________________________

Claim 6

An acoustic surface wave device comprising: a piezoelectric ceramic wafer consisting essentially of a solid solution of the ternary system Pb(Sn 1/2 Sb 1/2 )O 3 -PbTiO 3 -PbZrO 3 having a composition showing a phase transition between a ferroelectric rhombohedral low temperature phase (F R (LT)) and a ferroelectric rhombohedral high temperature phase (R R (HT)) at a temperature within the range from -20°0 C. to 80°; and at least one electrochemical transducing means for converting an electrical signal into acoustic surface waves and vise versa, said transducing means comprising interdigital transducing electrodes coupled to a surface of said piezoelectric ceramic wafer at a transducing region thereof, said composition consisting essentially of a main component expressed by the general formula: xPb(Sn.sub.1/2 Sb.sub.1/3)O.sub.3 -yPbTiO.sub.3 -zPbZrO.sub.3 wherein, x+y=z=1.00, and additives consisting of manganese in oxide form in an amount of 0.05 to 5.0 wt% in the form of MnO 2 and at least one element selected from the group consisting of magnesium and chromium in oxide form in respective amounts of 0.05 to 5.0 wt% in the form of MgO and Cr 2 O 3 , said main component having a composition in the compositional area defined by points A, B, C, D, E 1 , F 1 and G in FIG. 4, the sets of mol fractions of the three components at said points being as follows: ______________________________________ x y z ______________________________________ A 0.01 0.44 0.55 B 0.01 0.04 0.95 C 0.04 0.01 0.95 D 0.15 0.01 0.84 E.sub.1 0.25 0.01 0.74 F.sub.1 0.25 0.25 0.50 G 0.15 0.35 0.50. ______________________________________

Claim 7

An acoustic surface wave device according to claim 4, wherein said additives are MnO 2 and Cr 2 O 3 .

Claim 8

An acoustic surface wave device according to claim 5, wherein said main component has a composition expressed by the formula: 0.05Pb(Sn.sub.1/2 Sb.sub.1/2)O.sub.3 -0.30PbTiO.sub.3 -0.65PbZrO.sub.3 and wherein said additives are 0.4 wt% of MnO 2 and 1.0 wt% of CR 2 O 3 .

Claim 9

An acoustic surface wave device according to claim 4, wherein said main component has a composition expressed by the formula: 0.01Pb(Sn.sub.1/2 Sb.sub.1/2)O.sub.3 -0.44PbTiO.sub.3 -0.55PbZrO.sub.3 and wherein said additives are 2.0 wt% of MnO 2 and 2.0 wt% of Cr 2 O 3 .

Claim 10

An acoustic surface wave device according to claim 4, wherein said additives are MnO 2 and MgO.

Claim 11

An acoustic surface wave device according to claim 8, wherein said main component has a composition expressed by the formula: 0.10Pb(Sn.sub.1/2 Sb.sub.1/2)O.sub.3 -0.20PbTiO.sub.3 -0.70PbZrO.sub.3 and wherein said additives are 1.0 wt% of MnO 2 and 0.05 wt% of MgO.

Claim 12

An acoustic surface wave device according to claim 8, wherein said main component has a composition expressed by the formula: 0.10Pb(Sn.sub.1/2 Sb.sub.1/2)O.sub.3 -0.20PbTiO.sub.3 -0.70PbZrO.sub.3 and wherein said additives are 1.0 wt% of MnO 2 and 0.1 wt% of MgO.

Claim 13

An acoustic surface wave device according to claim 8, wherein said main component has a composition expressed by the formula : 0.20Pb(Sn.sub.1/2 Sb.sub.1/2)O.sub.3 -0.01PbTiO.sub.3 -0.79PbZrO.sub.3 and wherein said additives are 3.0 wt% of MnO 2 and 0.3 wt% of MgO.

Claim 14

An acoustic surface wave device according to claim 4, wherein said additives are MnO 2 , Cr 2 O 3 and MgO.

Claim 15

An acoustic surface wave device comprising: a piezoelectric ceramic wafer consisting essentially of a solid solution of the ternary system Pb(Sn 1/2 Sb 1/2 )O 3 -PbTiO 3 -PbZrO 3 having a composition showing a phase transition between a ferroelectric rhombohedral low temperature phase (F R (LT)) and a ferroelectric rhombohedral high temperature phase (R R (HT)) at a temperature within the range from -20° C. to +80° C.; and two interdigital transducers for converting an electrical signal into acoustic surface waves and visa versa, formed on a surface of said piezoelectric ceramic wafer at a transducing region thereof, said composition consisting essentially of a main component expressed by the general formula: xPb(Sn.sub.1/2 Sb.sub.1/2)O.sub.3 -yPbTiO.sub.3 -zPbZrO.sub.3 wherein, x+y+z=1.00, and an additive consisting of manganese in oxide form in an amount of 0.05 to 5.0 wt% in the form of MnO 2 , said main component having a composition in the compositional area defined by points A, B, C, D, E 1 , F 1 and G in FIG. 4, the sets of mol fractions of the three components at said points being as follows: ______________________________________ x y z ______________________________________ A 0.01 0.44 0.55 B 0.01 0.04 0.95 C 0.04 0.01 0.95 D 0.15 0.01 0.84 E.sub.1 0.25 0.01 0.74 F.sub.1 0.25 0.25 0.50 G 0.15 0.35 0.50. ______________________________________

Claim 16

An acoustic surface wave device comprising: a piezoelectric ceramic wafer consisting essentially of a solid solution of the ternary system Pb(Sn 1/2 Sb 1/2 )O 3 -PbTiO 3 -PbZrO 3 having a composition showing a phase transition between a ferroelectric rhombohedral low temperature phase (F R (LT)) and a ferroelectric rhombohedral high temperature phase (R R (HT)) at a temperature within the range from -20° C. to +80° C.; and two interdigital transducers for converting an electrical signal into acoustic surface waves and visa versa, formed on a surface of said piezoelectric ceramic wafer at a transducing region thereof, said composition consisting essentially of a main component expressed by the general formula: xPb(Sn.sub.1/2 Sb.sub.1/2)O.sub.3 -yPbTiO.sub.3 -zPbZrO.sub.3 wherein, x+y+z=1.00, and an additive consisting of manganese in oxide form in an amount of 0.05 to 5.0 wt% in the form of MnO 2 , said main component having a composition in the compositional area defined by points A, B, C, D, E 1 , F 1 and G in FIG. 4, the sets of mol fractions of the three components at said points being as follows: ______________________________________ x y z ______________________________________ A 0.01 0.44 0.55 B 0.01 0.04 0.95 C 0.04 0.01 0.95 D 0.15 0.01 0.84 E.sub.1 0.25 0.01 0.74 F.sub.1 0.25 0.25 0.50 G 0.15 0.35 0.50. ______________________________________

Claim 17

An acoustic surface wave device comprising: a piezoelectric ceramic wafer consisting essentially of a solid solution of the ternary system Pb(Sn 1/2 Sb 1/2 )O 3 -PbTiO 3 -PbZrO 3 having a composition showing a phase transition between a ferroelectric rhombohedral low temperature phase (F R (LT)) and a ferroelectric rhombohedral high temperature phase (F R (HT)) at a temperature within the range from -20° C. to +80° C.; and two interdigital transducers for converting an electrical signal into acoustic surface waves and vise versa, formed on a surface of said piezoelectric ceramic wafer at a transducing region thereof, said composition consisting essentially of a main component expressed by the general formula: xPb(Sn.sub.1/2 Sb.sub.1/2)O.sub.3 -yPbTiO.sub.3 -zPbZrO.sub.3 wherein, x+y+z=1.00, and additives consisting of manganese in oxide form in an amount of 0.05 to 5.0 wt% in the form of MnO 2 and at least one element selected from the group consisting of magnesium and chromium in oxide form in respective amounts of 0.05 to 5.0 wt % in the form of MgO and Cr 2 O 3 , said main component having a composition in the compositional area defined by points A, B, C, D, E 1 , F 1 and G in FIG. 4, the sets of mol fractions of the three components at said points being as follows: ______________________________________ x y z ______________________________________ A 0.01 0.44 0.55 B 0.01 0.04 0.95 C 0.04 0.01 0.95 D 0.15 0.01 0.84 E.sub.1 0.25 0.01 0.74 F.sub.1 0.25 0.25 0.50 G 0.15 0.35 0.50. ______________________________________

Claim 18

An acoustic surface wave device comprising: a piezoelectric ceramic wafer consisting essentially of a solid solution of the ternary system Pb(Sn 1/2 Sb 1/2 )O 3 -PbTiO 3 -PbZrO 3 having a composition showing a phase transition between a ferroelectric rhombohedral low temperature phase (F R (LT)) and a ferroelectric rhombohedral high temperature phase (F R (HT)) at a temperature within the range from -20° C. to +80° C.; and two interdigital transducers for converting an electrical signal into acoustic surface waves and vise versa, formed on a surface of said piezoelectric ceramic wafer at a transducing region thereof, said composition consisting essentially of a main component expressed by the general formula: xPb(Sn.sub.1/2 Sb.sub.1/2)O.sub.3 -yPbTiO.sub.3 -zPbZrO.sub.3 wherein, x+y+z=1.00, and additives consisting of manganese in oxide form in an amount of 0.05 to 5.0 wt% in the form of MnO 2 and at least one element selected from the group consisting of magnesium and chromium in oxide form in respective amounts of 0.05 to 5.0 wt % in the form of MgO and Cr 2 O 3 , said main component having a composition in the compositional area defined by points A, B, C, D, E 1 , F 1 and G in FIG. 4, the sets of mol fractions of the three components at said points being as follows: ______________________________________ x y z ______________________________________ A 0.01 0.44 0.55 B 0.01 0.04 0.95 C 0.04 0.01 0.95 D 0.15 0.01 0.84 E.sub.1 0.25 0.01 0.74 F.sub.1 0.25 0.25 0.50 G 0.15 0.35 0.50. ______________________________________