Crystal unit and method of measuring characteristics of the crystal unit

Patent metadata

Field	Value
Publication number	US-9410997-B2
Application number	US-201514734175-A
Country	US
Kind code	B2
Filing date	Jun 9, 2015
Priority date	Jul 4, 2014
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

A crystal unit may include a crystal piece, an excitation electrode configured to excite the crystal piece, a case configured to accommodate the crystal piece, an external electrode formed in the case and configured to be electrically connected to the excitation electrode, and an antenna formed in the case and configured to be electrically connected to the external electrode.

First claim

What is claimed is:

1. A crystal unit comprising:
a crystal piece;
an excitation electrode configured to excite the crystal piece;
a case configured to accommodate the crystal piece;
an external electrode formed in the case and configured to be electrically connected to the excitation electrode; and
an antenna formed in the case and configured to be electrically connected to the external electrode,
wherein the antenna is formed on an inner layer or a surface of the case.

2. The crystal unit according to claim 1 , further comprising:
an insulating portion formed between the antenna and the external electrode and configured to make an electrical isolation between the antenna and the external electrode; and
a conductor attachable to the case and configured to electrically connect the antenna and the external electrode in a state where the conductor is attached to the case.

3. The crystal unit according to claim 2 , further comprising:
a variable capacitor having one end connected to the conductor and the other end connected to a ground.

4. The crystal unit according to claim 1 , wherein
the case includes a cover.

5. The crystal unit according to claim 1 ,
wherein, when the crystal unit is connected to an IC (Integrated Circuit), the external electrode includes a first external electrode connected to an input side of an amplifier in the IC, and a second external electrode connected to an output side of the amplifier in the IC, and
wherein the antenna is electrically connected to the second external electrode.

6. The crystal unit according to claim 1 , wherein
the crystal unit is of a surface mounting type.

7. A method of measuring characteristics of a crystal unit, comprising:
disposing a conductor on an insulating portion between an antenna and an excitation electrode which excites a crystal piece in the crystal unit;
receiving an electromagnetic wave transmitted from the antenna when the crystal piece is excited;
analyzing a frequency of the received electromagnetic wave; and
changing capacitance of a variable capacitor having one end connected to the conductor and the other end connected to a ground,
wherein the analyzing a frequency of the received electromagnetic wave includes determining an oscillation frequency of the crystal unit based on a peak according to a peak frequency which is changed when the capacitance of the variable capacitor is changed.

Assignees

• Fujitsu Ltd

Inventors

• Kishi Masakazu
• Itoh Masaru
• Itoh Masayuki

Classifications

• H03B5/362

  the amplifier being a single transistor (H03B5/364 - H03B5/368 take precedence) · CPC title

• H01Q1/22

  by structural association with other equipment or articles · CPC title

• H01Q9/42

  with folded element, the folded parts being spaced apart a small fraction of the operating wavelength · CPC title

• H03B5/06

  Modifications of generator to ensure starting of oscillations · CPC title

• G06K19/073

  Special arrangements for circuits, e.g. for protecting identification code in memory (protection against unauthorised use of computer memory G06F12/14) · CPC title