US5075665A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laminated varistor
Assignee: Murata Manufacturing Co Ltd
•
Filing: 1989-09-08
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Granted: 1991-12-24
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Expires: 2009-09-08
Abstract
Abstract Respective first end portions of first and second internal electrodes are exposed at respective end surfaces of a varistor body, which is in the form of a rectangular parallelepiped. These end surfaces of the varistor body are covered with low resistance parts which include ceramic material in order to prevent the internal electrodes from decomposition. External electrodes are formed on the low resistance parts, so as, to be electrically connected with corresponding ones of the internal electrodes through the low resistance parts.
Inventors
- 👤 Hiroaki Taira
- 👤 Kazutaka Nakamura
- 👤 Yasunobu Yoneda
- 👤 Yukio Sakabe
- 👤 Yutaka Shimahara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:44
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/10; H01C7/102; H01C1/00; H01C1/14
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
128 words
A laminated varistor comprising: a varistor part formed of a ceramic material which has a varistor function; a plurality of internal electrodes arranged in parallel with each other, said internal electrodes being embedded within said varistor part, and respective connection portions thereof being electrically exposed to the exterior of said varistor part; at least two low resistance parts formed of a ceramic material, respective ones of said low resistance parts being electrically connected to said connection portion of said internal electrodes and protecting said internal electrode from external moisture; and at least two external terminal means on said varistor part which are electrically connected respectively to said low resistance parts, said connection portions of said internal electrodes being electrically exposed to the exterior through said low resistance parts.
Claim 2
Dependent Claim
128 words
A laminated varistor comprising: a varistor part formed of a ceramic material which has a varistor function; a plurality of internal electrodes arranged in parallel with each other, said internal electrodes being embedded within said varistor part, and respective connection portions thereof being electrically exposed to the exterior of said varistor part; at least two low resistance parts formed of a ceramic material, respective ones of said low resistance parts being electrically connected to said connection portion of said internal electrodes and protecting said internal electrode from external moisture; and at least two external terminal means on said varistor part which are electrically connected respectively to said low resistance parts, said connection portions of said internal electrodes being electrically exposed to the exterior through said low resistance parts.
Claim 3
Dependent Claim
105 words
A laminated varistor in accordance with claim 1, wherein said varistor part has first and second opposite end surfaces; said plurality of internal electrodes include first and second internal electrodes, said first and second internal electrodes being exposed at said first and second end surfaces respectively; said at least two low resistance parts include first and second low resistance parts covering said first and second end surfaces respectively; and said at least two external terminal means include first and second external electrodes formed on said first and second low resistance parts respectively and thereby being electrically connected to said first and second internal electrodes respectively.
Claim 4
Dependent Claim
100 words
A laminated varistor in accordance with claim 1, wherein said varistor part has first and second opposite major surfaces, extending in parallel with said internal electrodes, and first and second opposite end surface; said plurality of internal electrodes include internal electrodes of a first group and internal electrodes of a second group, said internal electrodes of said first and second groups being alternately arranged and electrically connected to said first and second end surfaces respectively; and said at least two low resistance parts include portions of said varistor part having lowered resistance at said first and second end surfaces respectively.
Claim 5
Dependent Claim
91 words
A laminated varistor in accordance with claim 3, wherein a predetermined one of said internal electrodes of said first group, which is adjacent to one of said major surfaces, is separated from said second end surface by a greater distance than the other internal electrodes of said first group; and a predetermined one of said internal electrodes of said second group, which is adjacent to the other of said major surface, is separated from said first end surface by a greater distance than the other internal electrodes of said second group.
Claim 6
Dependent Claim
45 words
A laminated varistor in accordance with claim 4, wherein said varistor part has an overall length, and the lengths of said predetermined ones of said internal electrodes of both said first and second groups are less than half the overall length of the varistor part.
Claim 7
Dependent Claim
29 words
A laminated varistor in accordance with claim 4, further comprising respective dummy electrodes embedded in said varistor part and substantially coplanar with said predetermined ones of said internal electrodes.
Claim 8
Dependent Claim
89 words
A laminated varistor in accordance with claim 1, wherein said varistor part has first and second opposite major surfaces extending in parallel with said internal electrodes; said internal electrodes include first and second internal electrodes; and said first low resistance part is in contact with said first internal electrode and forms a part of said first major surface of said varistor part and said second low resistance part is in contact with said second internal electrode and forms a part of said second major surface of said varistor part.
Claim 9
Dependent Claim
100 words
A laminated varistor in accordance with claim 7, wherein said internal electrodes include internal electrodes of a first group, including said first internal electrode, and internal electrodes of a second group, including said second internal electrode, said internal electrodes of said first and second groups being alternately arranged; said laminated varistor further comprising a first viahole connecting part defined in said varistor part which electrically connects said internal electrodes of said first group with each other and a second viahole connecting part defined in said varistor part which electrically connects said internal electrodes of said second group with each other.
Claim 10
Dependent Claim
35 words
A laminated varistor in accordance with claim 7, wherein said varistor part also has first and second opposite end surfaces, said low resistance parts being spaced away from said end surfaces of said varistor part.
Claim 11
Dependent Claim
175 words
A laminated varistor in accordance with claim 1, wherein said varistor part has a major surface extending in parallel with said internal electrodes; said internal electrodes include internal electrodes of a first group and internal electrodes of a second group, said internal electrodes of said first and second groups being alternately arranged; and said first low resistance part is in contact with one of said internal electrodes of said first group and forms a first part of said major surface of said varistor part and said second low resistance part is in contact with one of said internal electrodes of said second group and forms a second part, which is different from said first part, of said major surface of said varistor part; said laminated varistor further comprising a first viahole connecting part defined in said varistor part for electrically connecting said internal electrodes of said first group with each other and a second viahole connecting part defined in said varistor part for electrically connecting said internal electrodes of said second group with each other.
Claim 12
Dependent Claim
50 words
A laminated varistor in accordance with claim 1, wherein said varistor part is formed of a first ceramic material which is selected to have a varistor function after firing and said low resistance parts are formed of a second ceramic material which is selected to be redesigned semiconductive by firing.
Claim 13
Dependent Claim
55 words
A laminated varistor in accordance with claim 11, wherein said second ceramic material for forming said low resistance parts contains a ceramic material which is identical in composition to said ceramic material forming said varistor part and further contains at least one element selected from the group consisting of Al, Ga, Gd, Zn and Y.
Claim 14
Dependent Claim
31 words
A laminated varistor in accordance with claim 11, wherein said low resistance parts are obtained by applying said second ceramic material raw to said varistor part, and then firing the same.
Claim 15
Dependent Claim
25 words
A laminated varistor in accordance with claim 13, wherein said varistor part and said low resistance parts are cofired and are integrated with each other.
Claim 16
Dependent Claim
38 words
A laminated varistor in accordance with claim 1, wherein said varistor part and said low resistance parts are comprised in a common ceramic body, said low resistance parts being parts of said ceramic body having partially lowered resistance.
Claim 17
Dependent Claim
45 words
A laminated varistor in accordance with claim 15, wherein said low resistance parts are formed by applying paste containing at least one element selected from the group consisting of Al, Ga, Gd, Zn and Y to parts of said ceramic body and performing heat treatment.
Claim 18
Dependent Claim
30 words
A laminated varistor in accordance with claim 16, wherein said low resistance parts contain a ceramic material which is identical in composition to the ceramic material forming said varistor part.
Claim 19
Dependent Claim
19 words
A laminated varistor in accordance with claim 17, wherein said low resistance parts and said varistor part contain ZnO.
Claim 20
Dependent Claim
16 words
A laminated varistor in accordance with claim 18, wherein said low resistance parts further contain Zn.
Claim 21
Dependent Claim
21 words
A laminated varistor in accordance with claim 16, wherein said varistor part and said low resistance parts contain different ceramic materials.
Claim 22
Dependent Claim
17 words
A laminated varistor in accordance with claim 20, wherein said low resistance parts contain RuO 2 .
Claim 23
Dependent Claim
26 words
A laminated varistor in accordance with claim 15, wherein said low resistance parts are formed by applying a reducing solution to parts of said ceramic body.
Claim 24
Dependent Claim
18 words
A laminated varistor in accordance with claim 22, wherein said reducing solution is an organic borane compound solution.
Claim 25
Dependent Claim
21 words
A laminated varistor in accordance with claim 23, wherein said organic borane compound solution is a saturated solution of dimethylamine borane.
Claim 26
Dependent Claim
42 words
A laminated varistor in accordance with claim 15, wherein said varistor part is formed of a first ceramic material and said low resistance parts are obtained by applying a raw second ceramic material to said varistor part, and then firing the same.
Claim 27
Dependent Claim
24 words
A laminated varistor in accordance with claim 25, wherein said varistor part and said low resistance parts are cofired and integrated with each other.
Claim 28
Dependent Claim
25 words
A laminated varistor in accordance with claim 25, wherein said second ceramic material is applied to said varistor part in the form of a paste.
Claim 29
Dependent Claim
27 words
A laminated varistor in accordance with claim 25, wherein said second ceramic material is applied to said varistor part in the form of a ceramic green sheet.
Claim 30
Dependent Claim
137 words
A laminated varistor comprising; a varistor part formed of a ceramic material which has a varistor function; a plurality of internal electrodes arranged in parallel with each other, said internal electrodes being embedded within said varistor part, and having respective connection portions which are not physically exposed to the exterior of said varistor part; at least two low resistance parts formed of the same ceramic material as in said varistor part, respective ones of said low resistance parts being electrically connected to said connection portions of said internal electrodes and protecting said internal electrodes from external moisture; and at least two external terminal means on said varistor part which are electrically connected respectively to said low resistance parts, said connection portions of said internal electrodes thereby being electrically exposed to the exterior through said low resistance parts.
Claim 31
Dependent Claim
137 words
A laminated varistor comprising; a varistor part formed of a ceramic material which has a varistor function; a plurality of internal electrodes arranged in parallel with each other, said internal electrodes being embedded within said varistor part, and having respective connection portions which are not physically exposed to the exterior of said varistor part; at least two low resistance parts formed of the same ceramic material as in said varistor part, respective ones of said low resistance parts being electrically connected to said connection portions of said internal electrodes and protecting said internal electrodes from external moisture; and at least two external terminal means on said varistor part which are electrically connected respectively to said low resistance parts, said connection portions of said internal electrodes thereby being electrically exposed to the exterior through said low resistance parts.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-12-23 | 1995-06-24 | 1995-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-23 | 1999-06-24 | 1999-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-23 | 2003-06-24 | 2003-12-24 | $7700.00 | Window Closed / Lapsed |