Piezoelectric transducer and electrophoretic ink display apparatus using piezoelectric transducer

• US 20020011986A1
• Filed: 10/11/2001
• Published: 01/31/2002
• Est. Priority Date: 01/29/1999
• Status: Active Grant

• Current Assignee: Kazumasa Hasegawa, Tatsuya Shimoda
• Original Assignee: Kazumasa Hasegawa, Tatsuya Shimoda
• Inventors: Shimoda, Tatsuya, Hasegawa, Kazumasa
• Granted Patent: US 6,842,166 B2
• Time in Patent Office: Days
• US Class Current: 345/108
• 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, a first piezoelectric film layer, a second electrode layer, a second piezoelectric film layer, and a third electrode layer formed in that order on a substrate, wherein said first and second piezoelectric film layers are constrained so as not to expand or contract in a thickness direction.

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 wherein a first electrode layer, piezoelectric film layer, second electrode layer, and third electrode layer are formed on a supporting base wherein a cavity is formed;

and said second electrode layer and third electrode layer are formed in a pair with a space therebetween on the piezoelectric film layer located above said cavity.

6. The thin film piezoelectric transducer, according to claim 5, wherein said third electrode layer is formed to span the end surface and upper layer surface of said piezoelectric film layer.

7. The thin film piezoelectric transducer, according to claim 5, wherein the supporting base wherein said cavity is formed is a single crystal silicon substrate.

8. The thin film piezoelectric transducer, according to claim 5, comprising a diaphragm formed of a zirconia thin film between said supporting base and said first electrode layer.

9. The thin film piezoelectric transducer, according to claim 5, wherein said first, second, and third electrode layers are formed of a multilayered structure of platinum and titanium.

10. The thin film piezoelectric transducer, according to claim 5, wherein said piezoelectric film layer is formed of a lead-titanate-zirconate piezoelectric material.

11. The thin film piezoelectric transducer, according to claim 5, wherein an arbitrary voltage waveform is applied between said first electrode layer and said second electrode layer, and said arbitrary voltage waveform which has been amplified is output to between said first electrode layer and said third electrode layer.

12. An electrophoretic ink display apparatus comprising a plurality of electrophoretic ink display elements that comprise a plurality of capsules and wherein the color changes due to the movement of charged particles within the capsules;

the electrophoretic ink display apparatus further comprising;

a plurality of gate lines, a plurality of data lines intersecting with the gate lines, and thin film transistors disposed at the intersections of said gate lines and data lines;

wherein one source-drain of said thin film transistor is connected to said data line;

another source-drain of said thin film transistor is connected to the input side of said piezoelectric transducer; and

the output side of said piezoelectric transducer is connected to the electrode of the electrophoretic ink display element.

13. The electrophoretic ink display apparatus, according to claim 12, wherein said piezoelectric transducer is connected vibrateably with the upper portion of said thin film transistor.

14. The electrophoretic ink display apparatus, according to claim 12, wherein said piezoelectric transducer comprises a first electrode layer, a first piezoelectric film layer, a second electrode layer, a second piezoelectric film layer, and a third electrode layer, layered in that order on an insulating substrate;

and

wherein said first and second piezoelectric film layers are constrained so as not to expand or contract in a thickness direction.

15. The electrophoretic ink display apparatus, according to claim 14, wherein said first and second piezoelectric film layers are constrained so as not to expand or contract in a thickness direction by establishing a columnar structure on the upper portion of said piezoelectric transducer and pressing said columnar structure with an opposite substrate, whereon the upper electrode of said electrophoretic ink display element is established.

16. The electrophoretic ink display apparatus, according to claim 14, wherein said third electrode layer also functions as the lower electrode of said electrophoretic ink display element.

17. The electrophoretic ink display apparatus, according to claim 14, wherein said first, second, and third electrode layers are formed of a multilayered structure of platinum and titanium.

18. The electrophoretic ink display apparatus according to claim 14, wherein said first and second piezoelectric film layers are formed of a lead-titanate-zirconate piezoelectric material.

19. The electrophoretic ink display apparatus, according to claim 14, 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.

20. The electrophoretic ink display apparatus, according to claim 12, wherein said piezoelectric transducer comprises a first electrode layer, piezoelectric film layer, second electrode layer, and third electrode layer formed on a supporting base wherein a cavity is formed;

and said second electrode layer and third electrode layer are formed in a pair with a space therebetween on the piezoelectric film layer located above said cavity.

21. The electrophoretic ink display apparatus, according to claim 20, wherein said third electrode layer is formed to span the end surface and upper layer surface of said piezoelectric film layer.

22. The electrophoretic ink display apparatus, according to claim 20, wherein the supporting base wherein said cavity is formed is a single crystal silicon substrate.

23. The electrophoretic ink display apparatus, according to claim 20, wherein said first, second, and third electrode layers are formed of a multilayered structure of platinum and titanium.

24. The electrophoretic ink display apparatus, according to claim 20, wherein said first and second piezoelectric film layers are formed of a lead-titanate-zirconate piezoelectric material.

25. The electrophoretic ink display apparatus, according to claim 20, wherein an arbitrary voltage waveform is applied between said first electrode layer and said second electrode layer, and said arbitrary voltage waveform which has been amplified is output between said second electrode layer and said third electrode layer.