JP2000165086A - Electronic component case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress harmonic noise or electromagnetic noise from an electronic component in a case to the outside or from the outside to the electronic component by forming a conductive film at least partially on the bottom face of the case and bringing the conductive film to the ground potential along with a circuit board. SOLUTION: An electronic component made of piezoelectric material (e.g. a quartz oscillator) is contained in a case 3 made of ceramic material or resin material. A conductive film 1 of same material as a terminal part (subjected to metallization or metal stiffening) is formed at least partially on the bottom face of the case 3 and connected with the ground potential of a mounting a circuit board 2. Consequently, the case 3 is shielded entirely. Since shield effect of the bottom face of the case 3 is enhanced, harmonic noise or electromagnetic noise from the direction of the circuit board 2 mounting the case 3 is suppressed efficiently. Furthermore, the effect of noise from the case onto the outer circumference is also suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield structure of a container for accommodating a small-sized piezoelectric component to be mounted on a wireless communication device or a portable telephone mainly used in a mobile communication field or the like.

[0002]

2. Description of the Related Art Conventionally used electronic component containers are widely used in which a container shape composed of a metal lid and a ceramic laminated substrate is sealed by seam welding, and the surface mount type container is the mainstream in recent years. For this reason, the connection between the mounted circuit board and the container is established by a conductive portion (metallization process, electrode deposition process) formed on the side surface of the container or the bottom surface of the container. Therefore, the conductive portion (terminal portion) on the side surface or the bottom surface of the container has a structure formed substantially on the same surface as the container surface.

[0003] In recent years, electronic components have been rapidly reduced in size, weight, and thickness mainly in the field of mobile communication such as wireless communication devices and mobile phones. Electronic components that house surface acoustic wave elements) have shifted to higher frequency bands as transmission signals have become faster. Therefore, there is a problem of harmonic noise from the electronic component to the surroundings due to a high frequency band, and the peripheral component is affected by the harmonic noise and electromagnetic noise from the peripheral component.

Conventionally, in order to reduce these harmonic noises and electromagnetic noises, the shielding of the container structure has been strengthened to realize harmonic noises and electromagnetic noises.

[0005]

As described above, there is a recent tendency that there is a strong demand for miniaturization, weight reduction, and thinning mainly in the field of mobile communication such as wireless communication equipment and mobile phones, and that the material of the container is also conventional. The form is changing from metal to ceramic laminated substrates and resin materials. In particular, ceramic and resin materials, which are insulating materials, are grounded to the key points of the container in order to suppress the harmonic noise and electromagnetic noise from the electronic components inside the container from outside to the outside, and vice versa. To improve.

However, the entire electronic component container is shielded. However, as shown in FIG. 5, the conventional shield structure mainly performs only the upward shielding process of the electronic component container corresponding to the upper part of the mounting circuit board. The lower part of the so-called electronic component container that transmits the mounted circuit board
Then, the current problem is that almost no shielding effect is obtained.

[0007]

SUMMARY OF THE INVENTION In order to solve these problems, the present invention has been made to improve the shielding effect of an electronic component container, particularly in a downward direction (toward the bottom surface of the container). In which a conductive film is formed at a ground potential.

Therefore, when a conductive portion (terminal portion) with the mounted circuit board is arranged on the side surface of the electronic component container, a conductive film is formed on the entire bottom surface of the electronic component container. In the case of an electronic component container in which a conductive portion (terminal portion) is arranged on the bottom surface, the shielding effect is maximized by forming a conductive film on the bottom surface of the electronic component container except for the terminal portion that establishes conductivity with the mounting circuit board. The present invention significantly reduces external harmonic noise and electromagnetic noise with respect to the electronic component container, and similar noise exerted on the external periphery from the electronic component container, thereby improving the problem.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In each drawing, the same reference numeral indicates the same object. FIG. 1 shows a perspective view of an electronic component container 3 of the present invention. In FIG. 1, the material of the electronic component container 3 is an insulating material (ceramic material or resin material), and a piezoelectric material (crystal oscillator, crystal oscillator,
The electronic component of the surface acoustic wave element is accommodated. In the present embodiment shown in FIG. 1, the electronic component container 3 in which the electronic component is accommodated in the concave container and the lid is covered is provided. However, the electronic component is mounted on a flat base substrate, and the inverted concave shape is formed. Even if the electronic component container 3 is covered with a lid,
It does not depend on the form of the container. Further, at least a side surface of the electronic component container 3 of FIG.
The terminal portion 4 that establishes electrical connection with the semiconductor device is formed by a metallizing process or a metal vapor deposition process.

FIG. 2 is a plan view of the electronic component container 3 of FIG. 1 as viewed from the mounting circuit board 2 side (the bottom side of the electronic component container 3). Now, assuming that an electronic component housed in the electronic component container 3 is a crystal oscillator, as shown in a circuit diagram of FIG. 3, terminal portions A and B are connection terminals of the crystal oscillator, and The part C is to be grounded to the mounting circuit board 2 which is a feature of the present invention. Therefore, as shown in FIG.
By forming a conductive film 1 of the same material (metallization processing or metal addition processing) as that of the terminal portion 4 on at least a part of the bottom surface of the electronic component, the conductive film 1 is connected to the ground potential of the mounting circuit board 2. This is to improve the shielding of the whole container 3. If the terminal 5 other than the internal connection terminal among the terminals 4 shown in FIG. 3 is connected to the conductive film 1 as a ground (ground) terminal, it can be reliably grounded.

By increasing the shielding effect of the bottom surface of the electronic component container 3 as described above, as shown in the state diagram of FIG. 4, harmonic noise and electromagnetic waves from the direction of the mounting circuit board 2 on which the electronic component container 3 is mounted. Noise can be efficiently suppressed.

In the above-described embodiment, the electronic component container 3 for accommodating the piezoelectric vibrator has been described as an example. However, other electronic components accommodated in the container may be electronic devices such as a crystal oscillator and a surface acoustic wave device. The present invention can be applied to all the electronic component containers 3 that store electronic components that are affected by external harmonic noise and electromagnetic noise with respect to the component container 3 and similar noises that affect the external periphery from the electronic component container 3.

[0013]

According to the present invention, in an electronic component container made of an insulating material such as a ceramic or a resin material, a harmonic applied from the outside to the electronic component inside the container and vice versa from the electronic component inside the container to the outside. Noise and electromagnetic noise can be significantly suppressed, thus improving quality.

[Brief description of the drawings]

FIG. 1 is a perspective view of an electronic component container of the present invention.

FIG. 2 is a plan view of a bottom portion of the electronic component container of the present invention.

FIG. 3 is a layout diagram showing a circuit configuration of FIG. 2;

FIG. 4 is a state diagram illustrating noise leakage improved by the present invention.

FIG. 5 is a state diagram showing noise leakage seen in a conventional product.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductive film 2 Circuit board 3 Electronic component container

Claims (1)

[Claims] 1. An electronic component container comprising a piezoelectric material stored in a container made of an insulating material, wherein a conductive film is formed on at least a part of a bottom surface of the container so that the container can be grounded. Parts container.