JPH0722541A - High frequency apparatus - Google Patents

Abstract

PURPOSE:To provide a high frequency apparatus wherein a printed wiring structure constituting a high frequency circuit is high frequency sealed advantageously in the cost and the fabrication. CONSTITUTION:A printed wiring structure 3 where high frequency circuit parts 2 are assembled and wired on a printed board 1 is doubly covered with an insulating resin layer 4 and a conductive resin layer 5, whereby as a result there is brought about a state where the conductive resin layer 5 is earthed. With this state the printed wiring structure 3 is high frequency sealed with the conductive resin layer 5. The conductive resin layer 5 is obtained by blending metal powder into ordinary resin in the high mass production using a blowing process and a dipping process or a printing process together with the insulating resin layer 4. In the high frequency sealding structure with the conductive resin layer 5 the fabrication cost of a sealding member for wholly high frequency sealding the printed wiring structure 3 is lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency device such as an electronic tuner that requires a high frequency shield as a whole.

[0002]

2. Description of the Related Art A high-frequency device having a printed wiring body in which high-frequency circuit parts are assembled and printed on a printed circuit board is generally constructed by surrounding the printed wiring body with a chassis base made of a metal plate and a shield cover for high-frequency shielding. . For example, as shown in FIG. 4, such a high frequency device includes a printed wiring body (3) in which a high frequency circuit component (2) is mounted on a rectangular printed circuit board (1) and a rectangular frame-shaped chassis base ( 11) and a shield cover (12).

On the printed circuit board (1), in addition to the high frequency circuit component (2), for example, terminals (13) partially projected on the printed circuit board (1) are fixed. Chassis base (11)
The printed wiring body (3) is housed inside, and the terminal (13) is led out from the side wall of the chassis base (11). The opening of the chassis base (11) is covered with a shield cover (12), and the printed wiring body (3) is surrounded by the chassis base (11) and the shield cover (12). The grounded portion of the printed wiring body (3) is connected to the chassis base (11), the chassis base (11) and the shield cover (12) are grounded, and the printed wiring body (3) is shielded at a high frequency.

[0004]

The chassis base and the shield cover for high-frequency shielding the printed wiring body of the high-frequency device as a whole are made by press-molding a metal plate such as aluminum with a mold, and the shape thereof is the high-frequency device. It depends on the type. Therefore, the manufacturing cost of the high frequency shield member of the chassis base and the shield cover is increased due to the cost of the mold, making it difficult to reduce the cost of the high frequency device.

Further, since the shape of the chassis base and the shield cover molded by the mold is determined by the mold, there is no freedom to change the shape, and the adaptability to the design change of the printed wiring body is poor. , Making it difficult to change the design of the printed wiring board.

Therefore, the object of the present invention is to
It is an object of the present invention to provide a high-frequency device in which a printed wiring body that constitutes a high-frequency circuit is shielded at a high frequency cost-effectively.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a printed wiring body in which a high-frequency circuit component is assembled and wired on a printed circuit board is covered with an insulating resin layer, and the insulating resin layer is further covered with a conductive resin layer. The above object is achieved by shielding the printed wiring body with a high-frequency resin layer.

Further, according to the present invention, the tip portion of a conductive member such as a shield partition plate protruding from the printed circuit board is projected from the insulating resin layer, and the tip portion is electrically connected to the conductive resin layer. Is characterized by.

[0009]

[Function] The insulating resin layer and the conductive resin layer for covering the printed wiring body can be mass-produced by a spraying method or a dipping method,
In addition, it can be formed without using a mold, which reduces the manufacturing cost of the high frequency device. In addition, the insulating resin layer and the conductive resin layer are formed in a shape having a high degree of freedom according to the shape of the printed wiring body, so that the adaptability to the shape change and type change of the printed wiring body is improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Each embodiment will be described below with reference to FIGS. The same or corresponding parts are denoted by the same reference symbols throughout the cues including FIG.

In the high frequency device of the embodiment shown in FIGS. 1 (a) and 1 (b), a printed wiring body (3) having a high frequency circuit component (2) mounted on a printed circuit board (1) has an insulating resin layer (4). And the conductive resin layer (5) is double coated. Various terminals (6) are fixed to the printed board (1), and each terminal (6) is led out through the insulating resin layer (4) and the conductive resin layer (5) to the outside. The insulating resin layer (4) is first applied to the printed wiring body (3) by a spraying method, a dipping method, a printing method or the like, and then a conductive resin layer (5) is sprayed on the outer surface of the insulating resin layer (4). It is applied by the method, dip method, printing method, etc.

The insulating resin layer (4) is made of a resin material such as epoxy resin. The conductive resin layer (5) is made by mixing conductive powder such as metal powder into a resin material such as epoxy resin to give conductivity. By grounding the conductive resin layer (5), the conductive resin layer (5) becomes a high-frequency shield member for high-frequency shielding the printed wiring body (3).

For example, if the ground terminal (6 ') in the terminal (6) which is a conductive member of the printed wiring body (3) and the conductive resin layer (5) are connected, the conductive resin layer (5) The printed wiring body (3) is shielded by high frequency. In this case, each terminal (6) other than the ground terminal (6 ') is connected to the conductive resin layer (5).
Is insulated. Further, the conductive resin layer (5) may be used by being electrically connected to a ground member of an external device. Further, depending on the use of the high frequency device in FIG. 1, the outermost conductive resin layer (5) may be covered with the exterior insulating resin layer (4 ′) as shown by the chain line in FIG. 1 (b). .

The high-frequency device shown in FIGS. 2A to 2C shows an embodiment of a structure in which the specified high-frequency circuit portion (m) of the printed wiring body (3) is doubly high-frequency shielded. In this high-frequency device, a conductive member protruding from a printed board (1), for example, a tip of a shield partition plate (7) is connected to a conductive resin layer (5).

The shield partition plate (7) is a rectangular frame-shaped metal plate as shown in FIG. 2 (c) and surrounds the high frequency circuit part (m) partially formed on the printed circuit board (1). Projected on the printed circuit board (1). As shown in FIG. 2 (b),
An insulating resin layer (4) is applied to the inside and outside of the base of the shield partition plate (7), and the tip of the shield partition plate (7) is projected from the insulating resin layer (4), and this tip is made conductive. The resin layer (5). By doing so, the high frequency circuit section (m) of the printed circuit board (1) is shielded by the shield partition plate (7).
It is surrounded by a conductive resin layer (5) and has a high frequency shield with a double structure.

The high-frequency device shown in FIGS. 3 (a) and 3 (b) has a high-frequency circuit characteristic adjusting means (8) installed in a part of the printed wiring body (3). The characteristic adjusting means (8) is, for example, a coil adjusting screw, and is manually adjusted by a driver or the like from the outside. In such a high frequency device, the insulating cylinder (9) is fixed around the characteristic adjusting means (8), and the insulating resin layer (4) and the conductive resin layer (5) are provided on the outer periphery of the insulating cylinder (9). You can put it on. Further, after adjusting the characteristics of the high frequency device by the characteristic adjusting means (8), the insulating resin may be embedded in the insulating tube (9).

[0017]

According to the present invention, the insulating resin layer and the conductive resin layer for covering the printed wiring body can be formed at low cost with good mass productivity by a spraying method or a dipping method without using a mold. Further, since the conductive resin layer shields the printed wiring body as a whole with a high frequency, it is possible to reduce the cost of the high frequency device including the entire high frequency shield member. Also,
Since the shapes of the insulating resin layer and the conductive resin layer can be easily changed in accordance with the shape of the printed wiring body, the flexibility of the shape of the high frequency shield member made of the conductive resin layer is increased, and Make it easy to change the shape and type.

Further, by electrically connecting a conductive member such as a ground terminal or a shield partition plate protruding from the printed circuit board to the conductive resin layer, the conductive resin layer is grounded and a partial wiring of the printed wiring body is partially removed. Heavy high frequency shield is easily possible.

[Brief description of drawings]

1A is a plan view including a partially omitted portion of a high frequency device according to a first embodiment of the present invention, and FIG. 1B is a cross-sectional view of the high frequency device of FIG. 1A.

2A is a plan view including a partially omitted portion of a high-frequency device according to a second embodiment of the present invention, FIG. 2B is a cross-sectional view of the high-frequency device of FIG. 2A, and FIG. FIG. 3 is a perspective view of a part of a printed wiring body in the high frequency device of FIG.

3A is a plan view of a high frequency device according to a third embodiment of the present invention, and FIG. 3B is a partially enlarged cross-sectional view of the high frequency device of FIG. 3A.

FIG. 4 is a perspective view including a partially omitted portion of a conventional high frequency device.

[Explanation of symbols]

 1 Printed circuit board 2 High frequency circuit component 3 Printed wiring body 4 Insulating resin layer 5 Conductive resin layer 6'Conductive member (ground terminal) 7 Conductive member (shield partition plate)

Claims (3)

[Claims] 1. A printed circuit board is provided with an insulating resin layer for covering a printed wiring body in which high-frequency circuit parts are assembled and wired, and a conductive resin layer for covering the printed wiring body by high-frequency shielding. Characteristic high-frequency device. 2. The electrically conductive member projectingly provided on the printed circuit board has a tip portion protruding from the insulating resin layer, and the tip portion is electrically connected to the conductive resin layer. High frequency equipment. 3. The high frequency device according to claim 2, wherein the conductive member is a frame-shaped shield partition plate that partially surrounds the printed circuit board.