JP3057511U - Electromagnetic interference (EMI) countermeasure crystal oscillator and manufacturing method - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a crystal oscillator and a manufacturing method for electromagnetic interference (EMI) countermeasure [Constitution] A plastic case, an upper case, and a lower case in which an oscillator circuit in which a crystal unit and its driving circuit are mounted on a PCB are provided. A crystal oscillator with a structure that integrates a lead frame with a lead frame.

Description

[Detailed description of the invention]

[0001]

[Industrial applications]

 The present invention relates to a crystal oscillator.

[0002]

[Prior art]

 The conventional crystal oscillator has a shielding effect, but the case is made of metal. Caution was required, such as short-circuiting with other parts due to metal, and short-circuiting with lines on the PCB. Moreover, since it is made of metal, it is not suitable for weight reduction.

[0003]

[Problems to be solved by the invention]

 This is a crystal oscillator that can remove unwanted electromagnetic waves such as high frequency in a metal shield type plastic case that can be used as a product against plastic electromagnetic interference (EMI) with plastic.

[0004]

[Means for Solving the Problems]

 The present invention was devised in using a mold case.

[0005]

[Action]

 According to the present invention, high-frequency and low-frequency unnecessary electromagnetic waves are eliminated by the mechanism of dropping the high-frequency or unnecessary electromagnetic waves inside the crystal oscillator to the ground by the shield metal mesh inside the case and the spacing of the metal mesh. There is action.

[0006]

【Example】

 Hereinafter, the structure and manufacturing method of the present invention will be described in detail with reference to the drawings. FIG. 1 is a structural diagram of a crystal oscillator according to the present invention. FIG. 2 is a configuration diagram of the case manufacturing method. FIG. 1 is a structural diagram of a crystal oscillator. Reference numeral 1 denotes a crystal oscillator arranged on a PCB. Reference numeral 2 denotes a circuit driving IC arranged on the PCB, and reference numeral 3 denotes a circuit configuration PCB. Reference numeral 4 denotes a lead frame for external connection, which is used to connect a power input waveform output and ground connection with the lead frame. 5 is an upper case, 6 is a lower case, and 7 is a shield line. High frequency or unnecessary frequency can be dropped to ground by this shield line. Reference numeral 8 denotes a case shield line and a PCB ground contact point. FIG. 2 is a configuration diagram for forming a metal mesh on the case surface. a is a mold, b is a moving frame, and is a diagram of a method in which a plastic in which copper or iron powder is e-dissolved in the groove of c, is pushed into the plastic side by the moving frame for d moving strokes.

[0007]

[Effect of the invention]

 By transferring a metal shield line to plastic, a crystal oscillator capable of preventing electromagnetic interference (EMI) is realized. Also, a crystal oscillator that is lightweight and easy to handle is realized.

[Brief description of the drawings]

FIG. 1 is a structural diagram of a crystal oscillator according to the present invention.

FIG. 2 is a configuration diagram of a method of transferring copper powder or iron powder to plastic.

[Explanation of symbols]

 1: Crystal oscillator 2: IC 3: PCB 4: Lead frame 5: Upper case 6: Lower case 7: Shield line 8: Shield line and PCB ground contact point a: Mold b: Moving frame c: Groove ( (For copper powder or iron powder) d: Moving stroke e: Melted plastic

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[Procedure amendment]

[Submission date] November 26, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims for utility model registration

[Correction method] Change

[Correction contents]

[Utility model registration claims]

Claims (2)

[Utility model registration claims] At the oscillation frequency inside a crystal oscillator, a mesh-shaped metal pattern is formed inside a case for the purpose of shielding unnecessary electromagnetic waves such as high frequencies other than a target frequency and dropping them to the ground. 3. A crystal oscillator according to claim 1, wherein said crystal oscillator has a case having a mechanism for dropping unnecessary electromagnetic waves to ground. 2. A gap between meshes for shielding unnecessary electromagnetic waves (high frequency, etc.) inside a crystal oscillator is narrowed at a high frequency, and is widened at a low frequency to improve a shielding effect. The structure is such that the mesh pattern can be changed. The production of a mesh structure inside this case creates a mesh-like groove in the mold,
By placing copper or iron powder in this and molding it, a mesh line can be made inside the mold. This line is made in the same way as the upper case and lower case, and connected to the oscillator PCB ground line for shielding effect. 3. A crystal oscillator according to claim 2, wherein the crystal oscillator is a case having a structure for projecting.