ESD protection device and manufacturing method for same

Patent metadata

Field	Value
Publication number	US-10381806-B2
Application number	US-201715591223-A
Country	US
Kind code	B2
Filing date	May 10, 2017
Priority date	Dec 18, 2014
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

An ESD protection device includes a bare unitary body, and a first discharge electrode and a second discharge electrode that are disposed inside the bare unitary body. The first discharge electrode and the second discharge electrode are opposed to each other with a gap interposed therebetween. The bare unitary body includes a cavity in which the gap between the first discharge electrode and the second discharge electrode is located, and to which the first discharge electrode and the second discharge electrode are exposed. A first space of the cavity on a side closer to the first discharge electrode is smaller than a second space of the cavity on a side closer to the second discharge electrode.

First claim

What is claimed is:

1. An ESD protection device comprising:
a body including a cavity; and
a first discharge electrode and a second discharge electrode that are located inside the body; wherein
the first discharge electrode and the second discharge electrode are opposed to each other with a gap located therebetween;
the gap between the first discharge electrode and the second discharge electrode is located in the cavity of the body;
the first discharge electrode and the second discharge electrode are exposed to the cavity of the body;
the cavity includes a first space located on a side of the cavity closer to the first discharge electrode and a second space located on a side of the cavity closer to the second discharge electrode;
the first space of the cavity is smaller than the second space of the cavity; and
a degree of concentration of an electric field in the first space is larger than a degree of concentration of an electric field in the second space.

2. The ESD protection device according to claim 1 , wherein a length of the first space in a height direction of the body is smaller than a length of the second space in the height direction of the body.

3. The ESD protection device according to claim 1 , wherein
in a vertical section extending in a direction in which the first discharge electrode and the second discharge electrode are opposed to each other and in a height direction of the body:
the first space includes a first sectional area surrounded by an inner surface of the cavity, an outer surface of the first discharge electrode, and a first linear line that contacts an end portion of the first discharge electrode on a side closer to the second discharge electrode and that extends in the height direction; and
the second space includes a second sectional area surrounded by the inner surface of the cavity, an outer surface of the second discharge electrode, and a second linear line that contacts an end portion of the second discharge electrode on a side closer to the first discharge electrode and that extends in the height direction; and

the first sectional area of the first space is smaller than a second sectional area of the second space.

4. The ESD protection device according to claim 3 , wherein, in the vertical section, a first angle defined by the inner surface of the cavity and the outer surface of the first discharge electrode is smaller than a second angle defined by the inner surface of the cavity and the outer surface of the second discharge electrode.

5. The ESD protection device according to claim 4 , wherein the first angle is an acute angle, and the second angle is 90° or substantially 90°, or an obtuse angle.

6. The ESD protection device according to claim 1 , wherein
the body includes a first portion in which the cavity is located and a second portion which is joined with the first portion and in which the first discharge electrode and the second discharge electrode are located; and
a level difference interface is located at a joined boundary between the first portion and the second portion.

7. The ESD protection device according to claim 1 , wherein each of the first discharge electrode and the second discharge electrode has a strip shape.

8. The ESD protection device according to claim 1 , wherein an inner surface of the cavity has a shape of a triangular or substantially triangular prism.

9. The ESD protection device according to claim 1 , wherein a first end portion of the first discharge electrode is exposed at a first end surface of the body and a second end portion of the first discharge electrode is located inside the body.

10. The ESD protection device according to claim 1 , wherein
an end portion of the first discharge electrode is exposed at a first end surface of the body; and
an end portion of the second discharge electrode is exposed at a second end surface of the body that opposes the first end surface of the body.

11. The ESD protection device according to claim 1 , further comprising a discharge auxiliary electrode that electrically connects the first discharge electrode to the second discharge electrode.

12. The ESD protection device according to claim 11 , wherein the discharge auxiliary electrode at least partially overlaps the gap between the first discharge electrode and the second discharge electrode.

13. The ESD protection device according to claim 11 , wherein the discharge auxiliary electrode has a rectangular or substantially rectangular shape.

14. The ESD protection device according to claim 11 , wherein a size of the cavity in a width direction of the body is the same or substantially the same as a size of the discharge auxiliary electrode in the width direction.

15. The ESD protection device according to claim 11 , wherein a size of the cavity in a length direction of the body is larger than a size of the discharge auxiliary electrode in the length direction.

16. The ESD protection device according to claim 1 , further comprising a first outer electrode and a second outer electrode located on an outer surface of the body.

17. The ESD protection device according to claim 16 , wherein the first discharge electrode is electrically connected to the first outer electrode, and the second discharge electrode is electrically connected to the second outer electrode.

18. An electronic device, comprising:
a first terminal; and
the ESD protection device according to claim 16 ; wherein
the first outer electrode is electrically connected to the first terminal and the second outer electrode is connected to ground.

Assignees

• Murata Manufacturing Co

Inventors

• Yasunaka Katsumi
• Adachi Jun

Classifications

• H01T1/20 Primary

  Means for starting arc or facilitating ignition of spark gap · CPC title

• H01T21/00

  Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs · CPC title

• H01T4/12

  hermetically sealed · CPC title