MAGNETIC FIELD MEASURING APPARATUS AND METHOD FOR MANUFACTURING SAME

• US 20140306700A1
• Filed: 11/18/2011
• Published: 10/16/2014
• Est. Priority Date: 11/18/2011
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Osabe, Taro, Suzuki, Seiichi, Kandori, Akihiko, Kawabata, Ryuzo, Kamada, Yudai
• Granted Patent: US 9,310,447 B2
• Time in Patent Office: Days
• US Class Current: 324/244.1
• CPC Class Codes: G01R 3/00 Apparatus or processes specially adapted for the manufacture or maintenance of measuring instruments , e.g. of probe tips
• CPC Class Codes: G01R 33/0322 using the Faraday or Voigt effect
• CPC Class Codes: G01R 33/26 using optical pumping
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

In order to provide a magnetic field measuring apparatus facilitating the pressure control in a gas cell, or capable of inspecting the internal pressure of the gas cell without using any special process, the magnetic field measuring apparatus is configured such that a process layer of the magnetic field measuring apparatus has such a structure that includes a first hollow portion and a second hollow portion provided opposed to first hollow portion with a first isolation wall interposed therebetween. Alternatively, a method for manufacturing the magnetic field measuring apparatus includes breaking the first isolation wall after generating alkali metal (FIG. 17 and FIG. 20).

Claims

1. A magnetic field measuring apparatus comprising:

a first sealing member;

a second sealing member; and

a process layer sealed by the first sealing member and the second sealing member,

wherein the process layer includes a first hollow portion in which alkali metal gas is sealed, and a second hollow portion provided opposed to the first hollow portion with a first isolation wall interposed therebetween.

2. The magnetic field measuring apparatus according to claim 1, wherein the process layer has a structure in which a first process member and a second process member are stacked,

the second hollow portion is provided inside of the first process member, and is sealed by the first sealing member, and

the first hollow portion is provided inside of the first process member and inside of the second process member, and is sealed by the first sealing member and the second sealing member.

3. The magnetic field measuring apparatus according to claim 1, wherein the first hollow portion and the second hollow portion are sealed by the first sealing member and the second sealing member.

4. The magnetic field measuring apparatus according to claim 1, wherein the process layer further includes a third hollow portion provided opposed to the first hollow portion with a second isolation wall interposed therebetween, and

a stress that occurs with the second isolation wall when a predetermined pressure is applied is different from that of the first isolation wall.

5. The magnetic field measuring apparatus according to claim 1, wherein the second hollow portion is vacuum-sealed.

6. The magnetic field measuring apparatus according to claim 1, wherein the first sealing member and the second sealing member is made of a material that transmits light in an absorption wavelength band of the alkali metal.

7. The magnetic field measuring apparatus according to claim 6, wherein the material that transmits light in the absorption wavelength band of the alkali metal is glass.

8. The magnetic field measuring apparatus according to claim 1, wherein the process layer is made of a nonmagnetic material.

9. The magnetic field measuring apparatus according to claim 1, wherein the nonmagnetic material is silicon.

10. A method for manufacturing a magnetic field measuring apparatus including a first sealing member, a second sealing member, and a process layer sealed by the first sealing member and the second sealing member, wherein the process layer includes a first hollow portion and a second hollow portion provided with a first isolation wall interposed therebetween,

the method comprising:

(a) generating alkali metal gas in the first hollow portion; and

(b) after (a), breaking a portion of the first isolation wall by increasing the stress applied to the first isolation wall caused by the pressure inside of the first hollow portion to a level higher than a destructive limitation stress.

11. The method for manufacturing the magnetic field measuring apparatus according to claim 10,

wherein in (a), not only the alkali metal gas but also a second gas made of nonmagnetic gas or rare gas are generated, and

in (b), the stress applied to the first isolation wall caused by the pressure of the first hollow portion is increased to a level higher than a destructive limitation stress, by increasing the pressure of the second gas.

12. A method for manufacturing a magnetic field measuring apparatus including a first sealing member, a second sealing member, and a process layer sealed by the first sealing member and the second sealing member, wherein the process layer has a structure in which the first process member and the second process member are stacked, and a first hollow portion is provided inside of the first process member and inside of the second process member, and a second hollow portion is provided inside of the first process member with a first isolation wall interposed therebetween,

the method comprising:

(a) generating alkali metal gas in the second hollow portion; and

(b) after (a), breaking a portion of the first isolation wall.

13. The method for manufacturing the magnetic field measuring apparatus according to claim 12, wherein in (b), the first isolation wall is broken by laser light.

14. The method for manufacturing the magnetic field measuring apparatus according to claim 12, wherein in (b), the stress applied to the first isolation wall caused by the pressure inside of the first hollow portion is increased to a level higher than a destructive limitation stress, thus breaking the first isolation wall.

15. The method for manufacturing the magnetic field measuring apparatus according to claim 12, wherein in (a), not only the alkali metal gas but also a second gas made of nonmagnetic gas or rare gas are generated.