Piezoelectric transducer and electrophoretic ink display apparatus using piezoelectric transducer

• US 6,842,166 B2
• Filed: 10/11/2001
• Issued: 01/11/2005
• Est. Priority Date: 01/29/1999
• Status: Expired due to Fees

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Hasegawa, Kazumasa, Shimoda, Tatsuya
• Primary Examiner(s): Tran, Henry N.
• Application Number:
  US09/975,706
• Publication Number:
  US 20020011986A1
• Time in Patent Office: 1,188 Days
• Field of Search: 345/80, 345/81, 345/84, 345/85, 345/107, 345/108, 359/290, 359/295, 359/296, 310/317, 310/318, 310/328, 310/330, 310/342, 310/363, 310/365, 428/137, 428/138
• US Class Current: 345/107
• CPC Class Codes: B06B 1/0688 with foil-type piezoelectric elements, e.g. PVDF
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/1685 Operation of cells; Circuit arrangements affecting the entire cell
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• CPC Class Codes: G09G 3/344 based on particles moving in a fluid or in a gas, e.g. electrophoretic devices electrophoretic devices per se G02F1/167
• CPC Class Codes: G09G 3/3493 using light modulating elements actuated by a piezoelectric effect
• CPC Class Codes: H10N 30/40 with electrical input and electrical output, e.g. functioning as transformers
• CPC Class Codes: H10N 39/00 Integrated devices, or assemblies of multiple devices, comprising at least one piezoelectric, electrostrictive or magnetostrictive element covered by groups H10N30/00 – H10N35/00
• CPC Class Codes: Y10T 428/24322 Composite web or sheet
• CPC Class Codes: Y10T 428/24331 including nonapertured component

Abstract

A first electrode layer 12, a first piezoelectric film layer 13, a second electrode layer 14, a second piezoelectric film layer 15, and a third electrode layer 16 are layered in that order on a substrate 11; these are constrained so as not to expand or contract in a thickness direction and a piezoelectric transducer is constructed thereby. A plurality of gate lines 201 and 202, a plurality of data lines 203 and 204 intersecting with the gate lines, and thin film transistors 205 and 207, disposed at the intersections of the abovementioned gate lines and data lines, are established; one source-drain of the abovementioned thin film transistors is connected to the abovementioned data lines; another source-drain of the abovementioned thin film transistors is connected to the input sides of the abovementioned thin film piezoelectric transducers 208 through 210; the output sides of the abovementioned thin film piezoelectric transducers are connected to the electrodes of electrophoretic ink display elements; and an electrophoretic ink display apparatus is constructed thereby.

Claims

1. A thin film piezoelectric transducer comprising:

a first electrode layer disposed on a substrate;

a first piezoelectric film layer disposed on said first electrode layer;

a second electrode layer disposed on said first piezoelectric film layer;

a second piezoelectric film layer disposed on said second electrode layer; and

a third electrode layer disposed on said second piezoelectric film layer, wherein said first and second piezoelectric film layers are constrained so as not to expand or contract.

2. The thin film piezoelectric transducer, according to claim 1, wherein said first, second, and third electrode layers are formed of a multilayered structure of platinum and titanium.

3. The thin film piezoelectric transducer, according to claim 1, wherein said first and second piezoelectric film layers are formed of a lead-titanate-zirconate piezoelectric material.

4. The thin film piezoelectric transducer, according to claim 1, wherein an arbitrary voltage waveform is input to said first piezoelectric film layer and said arbitrary voltage waveform which has been amplified is output to said second piezoelectric film layer.

5. A thin film piezoelectric transducer comprising:

a substrate;

a first electrode layer disposed on said substrate, the first electrode layer including layers of platinum and titanium;

a first piezoelectric film layer disposed on said first electrode layer, the first piezoelectric film layer containing lead zirconate titanate;

a second electrode layer disposed on said first piezoelectric film layer, the second electrode layer including layers of platinum and titanium;

a second piezoelectric film layer disposed on said second electrode layer, the second piezoelectric film layer containing lead zirconate titanate; and

a third electrode layer disposed on said second piezoelectric film layer, the third electrode layer including layers of platinum and titanium,

wherein said first and second piezoelectric film layers are constrained to not expand to contract; and

wherein upon application of a first voltage to said first piezoelectric film layer, a second voltage is output by the second piezoelectric film layer that is proportional to a square of an electromechanical coupling constant and a ratio of a thickness of the first piezoelectric film layer and a thickness of the second piezoelectric film layer.

6. A thin film piezoelectric transducer comprising:

a supporting base wherein a cavity is formed;

a diaphragm comprised of a zirconia film disposed on said supporting base;

a first electrode layer disposed on a portion of said diaphragm, the first electrode layer including layers of platinum and titanium;

a piezoelectric film layer disposed on a portion of said first electrode layer and a portion of said diaphragm, the piezoelectric film layer containing lead zirconate titanate;

a second electrode layer disposed on a portion of said piezoelectric film layer, the second electrode layer including layers of platinum and titanium; and

a third electrode layer disposed on a portion of said piezoelectric film layer and a portion of said diaphragm,

wherein said second electrode layer and third electrode layer are disposed as a pair with a space therebetween on the piezoelectric film layer located above said cavity;

said third electrode layer is formed to span an end surface and an upper layer surface of said piezoelectric film layer; and

wherein upon application of an alternating voltage between the first electrode layer and the second electrode layer, an amplified voltage is output from between the first electrode layer and third electrode layer.

7. The thin film piezoelectric transducer according to claim 6, wherein the alternating voltage is an alternating voltage waveform.

8. A thin film piezoelectric transducer comprising:

a first electrode layer disposed on a substrate;

a first piezoelectric film layer disposed on said first electrode layer;

a second electrode layer disposed on said first piezoelectric film layer;

a second piezoelectric film layer disposed on said second electrode layer; and

a third electrode layer disposed on said second piezoelectric film layer,

wherein each of said first piezoelectric film layer and said second piezoelectric film layer are fully constrained so as not to expand or contract.