JP2010182928A - High-frequency unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-frequency unit wherein grounding enhancement of a high-frequency circuit is easily and surely performed. <P>SOLUTION: The high-frequency unit includes a circuit board 1 where the high-frequency circuit is arranged, a shield frame 5 housing the circuit board 1, a shield plate 6 partitioning the internal space of the shield frame 5, and a lower cover 7 and an upper cover 8 covering a lower opening and an upper opening of the shield frame 5, wherein the circuit board 1 is grounded to the shield plate 6, and leg parts 6a of the shield plate 6 penetrate the circuit board 1. A first tongue piece 7b and a second tongue piece 7c of short size which are formed by cutting and raising parts of the lower cover 7 are made to abut against corresponding leg parts 6a respectively. Both the tongue pieces 7b and 7c are in the same shape and have the same size and while the first tongue piece 7b extends obliquely from one side edge of a connecting bar 7d as a base end toward the circuit board 1, the first tongue piece 7c extends obliquely from the other side edge of the connecting bar 7d as a base end toward the circuit board 1. Further, both the tongue pieces 7b and 7c share the connecting bar 7d on the base end sides to therefore be rockable in one. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a high-frequency unit in which a circuit board covered with a shield frame and a cover body is grounded to a shield plate and a ground is strengthened by bringing a part of the cover body into contact with the shield plate.

  In a high-frequency unit in which a circuit board on which a high-frequency circuit is arranged is housed and held in a shield case made of sheet metal, a conventional general shield case has a shield frame (frame body) assembled in a rectangular shape or the like, and a shield It consists of a shield plate (partition plate) that partitions the internal space of the frame, and an upper cover and a lower cover that close the upper and lower openings of the shield frame, respectively. The shield frame and the shield plate are a single metal plate. Often formed by bending. The circuit board is held by a shield frame and a shield plate, and the terminal group protrudes downward. The circuit board is provided with a high-frequency circuit such as a tuner section and an IF section, and the grounding section of the high-frequency circuit is shielded. Soldered to the board. In addition, a plurality of elastic tongue pieces formed by cutting and raising predetermined portions of the lower cover are elastically contacted with the shield plate, thereby strengthening the ground of the high-frequency circuit (for example, see Patent Document 1). .

  In the conventional high-frequency unit configured as described above, since the high-frequency circuit disposed on the circuit board is covered with the shield case, it is possible to reduce the jump-in and jump-out of electromagnetic noise. Also in the shield case, the electromagnetic noise of the circuit part that becomes a noise source is blocked by the shield plate to make it difficult to leak to another circuit part, and the elastic tongue of the lower cover is elastically contacted with the shield plate, and the high frequency circuit Since the ground is strengthened, the structure is less susceptible to electromagnetic noise. In this high-frequency unit, the shield case is placed and fixed on the motherboard, and the terminal group is connected to an external circuit on the motherboard side.

Japanese Patent Laid-Open No. 6-2751979

  By the way, in the above-described high-frequency unit, when the circuit parts that are noise sources (for example, the tuner part and the IF part) must be disposed close to each other due to restrictions on the circuit design of the circuit board, both circuit parts In addition to partitioning with a shield plate, the ground of both circuit parts must be specially strengthened. In such a case, the required ground reinforcement cannot be achieved even if the elastic tongue piece, which is a long and thin cut-and-raised piece, is brought into elastic contact with the shield plate. Therefore, as shown in FIG. The pair of convex portions 12a formed by the processing was brought into contact with the corresponding leg portions 11a of the shield plate 11, respectively. In FIG. 4, reference numeral 10 denotes a shield frame, 13 denotes an upper cover, 14 denotes a circuit board, and 15 denotes a terminal. Reference numeral 12b denotes an elastic tongue formed on the lower cover 12.

  However, since the convex portion 12a having poor elasticity cannot absorb the variation in the height position of the leg portion 11a of the shield plate 11, one convex portion 12a formed at two adjacent positions is used as the corresponding leg portion 11a. There is a possibility that the other convex portion 12a does not come into contact with the corresponding leg portion 11a even if they are brought into contact with each other. In this case, the ground reinforcement of the high-frequency circuit becomes insufficient, and performance degradation is forced.

  The present invention has been made in view of such a state of the prior art, and an object of the present invention is to provide a high-frequency unit capable of easily and reliably strengthening the ground of a high-frequency circuit.

In order to achieve the above object, in the present invention,
A circuit board on which a high-frequency circuit is provided, a sheet metal shield frame that is formed in a frame shape having an opening and accommodates the circuit board, and a sheet metal that is fitted to the shield frame so as to close the opening. And a shield plate made of sheet metal for partitioning the internal space of the shield frame, the circuit board is grounded to the shield plate, and a part of the cover body is cut and raised to form the shield plate In the high frequency unit abutted on, the cover body includes a connecting bar, a first tongue piece having one side edge of the connecting bar as a base end, and the other side edge of the connecting bar as a base end. A second tongue piece, and the first and second tongue pieces respectively extend obliquely toward the circuit board and abut against the shield plate, and the first and second tongue pieces are The structure is formed so as to be able to swing integrally. It was.

  In the high-frequency unit configured as described above, the first and second tongue pieces sharing the connecting bar on the base end side can swing integrally, and the height of the shield plate and the tongue piece itself varies. When one tongue piece is pushed into the shield plate, the seesaw operation is performed around the connecting bar, and the other tongue piece is pushed in the opposite direction. It can be made to contact. Moreover, since it is not necessary to form these 1st and 2nd tongue pieces as an elastic piece, a length dimension can be set short and it cuts and raises a part of cover body and forms the 1st and 2nd tongue pieces. Is also easy. Therefore, the ground reinforcement of the desired circuit portion of the high-frequency circuit can be reliably and effectively performed by the short first and second tongue pieces formed on the cover body.

  In the above configuration, the cover body is a lower cover that closes the lower opening of the shield frame, and the two adjacent leg portions of the shield plate pass through the circuit board, and the first tongue piece and the second tongue piece. Are not in contact with each other, and it is not necessary to form notches or holes in the upper cover that closes the upper opening of the shield frame, and the ground reinforcement of the two adjacent circuit parts of the high-frequency circuit is reliable and effective. Therefore, it is preferable.

  In the above configuration, it is preferable that the first tongue piece and the second tongue piece have the same shape and size, and this makes it easy to swing both tongue pieces integrally.

  In the high frequency unit of the present invention, when one tongue piece is pushed into the shield plate due to variations in the height position of the shield plate or the tongue piece itself, the seesaw operation is performed around the connecting bar, and the other tongue piece is Since it is pushed in the opposite direction, the first and second tongue pieces can be reliably brought into contact with the shield plate, and both the tongue pieces do not need to be formed as elastic pieces. Can be set short. Therefore, the short first and second tongue pieces formed on the sheet metal cover body have an excellent effect that the ground reinforcement of the high-frequency circuit can be easily, reliably and effectively performed.

It is a perspective view which shows a shield frame, a lower cover, etc. with the external view of the high frequency unit which concerns on the example of embodiment of this invention. It is an enlarged view which shows the 1st and 2nd tongue piece in the principal part of FIG. It is sectional drawing of this high frequency unit. It is sectional drawing of the high frequency unit which concerns on a prior art example.

  Embodiments of the present invention will be described below with reference to FIGS. The high-frequency unit shown in these drawings includes a circuit board 1 on which high-frequency circuits (not shown) such as a tuner section and an IF section are disposed, a shield case 2 that houses and holds the circuit board 1, and a circuit board. 1 is mainly constituted by a group of terminals 3 which are led out from 1 and project outward, and an RF connector 4 which is fixed to the shield case 2 and projects outward. The high-frequency unit is mounted on the mother board 9 by mounting and fixing the shield case 2 on the mother board 9 (see FIG. 3) and connecting the terminals 3 to an external circuit. In addition, since the high-frequency circuit disposed on the circuit board 1 is covered with the shield case 2, the jumping and jumping of electromagnetic noise is reduced.

  The shield case 2 includes a sheet metal shield frame (frame body) 5 assembled in a rectangular shape for housing the circuit board 1, a sheet metal shield plate (partition plate) 6 for partitioning the internal space of the shield frame 5, and A sheet metal lower cover 7 that closes the lower opening of the shield frame 5 and a sheet metal upper cover 8 that closes the upper opening of the shield frame 5 are configured. The shield frame 5 and the shield plate 6 are formed by bending a single metal plate, and a plurality of mounting legs 5 a fixed to the mother board 9 project from the lower end portion of the shield frame 5. A plurality of leg portions 6a projecting from the circuit board 1 and facing the lower cover 7 project from the lower end portion of the shield plate 6, and these leg portions 6a are soldered to the grounding portion of the high-frequency circuit. In addition, tongue pieces 7a to 7c of the lower cover 7 described later are brought into contact with a part of the leg portions 6a (see FIG. 3). Both the lower cover 7 and the upper cover 8 are fitted to the shield frame 5 by utilizing the elasticity of the peripheral portion.

  The circuit board 1 is held by a shield frame 5 and a shield plate 6 so that an antenna signal is supplied to the high-frequency circuit via an RF connector 4. Since the plurality of circuit parts constituting the high-frequency circuit are partitioned by the shield plate 6 in the internal space of the shield frame 5, electromagnetic noise interference is unlikely to occur between different circuit parts. The grounding portion of the high frequency circuit is electrically connected to the shield frame 5 and the shield plate 6.

  The lower cover 7 is formed with an elastic tongue piece 7a and short first and second tongue pieces 7b and 7c by cutting and raising a plurality of portions. These tongue pieces 7a to 7c are in contact with different leg portions 6a of the shield plate 6, respectively, thereby strengthening the ground of the high-frequency circuit. Among these, the first and second tongue pieces 7b and 7c are formed to specially strengthen the ground of the two circuit portions that are noise sources, and are adjacent to the shield plate 6 as shown in FIG. The first tongue piece 7b and the second tongue piece 7c are individually brought into contact with the two leg portions 6a. As shown in FIGS. 1 and 2, the first tongue piece 7b is a triangular tongue piece extending obliquely toward the circuit board 1 with one side edge of the connecting bar 7d formed in the lower cover 7 as a base end, The second tongue piece 7c is a triangular tongue piece extending obliquely toward the circuit board 1 with the other side edge of the connecting bar 7d as a base end. These first and second tongue pieces 7b and 7c have the same shape and size. Further, since both tongue pieces 7b and 7c share the connecting bar 7d on the base end side, they can swing integrally.

  As described above, the lower cover 7 of the high-frequency unit according to the present embodiment is formed with the first and second tongue pieces 7b and 7c that can swing integrally with the connecting bar 7d on the base end side. When one tongue piece 7b (or 7c) is pushed into the corresponding leg portion 6a due to variations in the height position of each leg portion 6a of the shield plate 6 and the height position of the tongue pieces 7b and 7c itself, Since the seesaw operation around the connecting bar 7d is performed and the other tongue piece 7c (or 7b) is pushed in the opposite direction, both the tongue pieces 7b and 7c are securely attached to the corresponding leg portions 6a. It can be made to contact. Further, since the first and second tongue pieces 7b and 7c do not need to be formed as elastic pieces, the length dimension can be set short. Therefore, the ground reinforcement of the desired circuit portion of the high-frequency circuit can be reliably and effectively performed by the first and second tongue pieces 7b and 7c. In addition, it is easy to cut and raise a part of the lower cover 7 to form the elastic tongue piece 7a and the first and second tongue pieces 7b and 7c. Further, each of the tongue pieces 7a to 7c is formed on the lower cover 7, and it is not necessary to form a similar tongue piece on the upper cover 8, so that there is no possibility of adversely affecting the shielding performance.

  The first tongue piece 7b and the second tongue piece 7c may be different in shape and size, but the shape and size of both tongue pieces 7b and 7c are different as in the present embodiment. It is preferable that the two tongue pieces 7b and 7c are easily swung integrally.

DESCRIPTION OF SYMBOLS 1 Circuit board 2 Shield case 3 Terminal 4 RF connector 5 Shield frame (frame body)
6 Shield plate (partition plate)
6a Leg 7 Lower cover 7a Elastic tongue 7b First tongue 7c Second tongue 7d Connecting bar 8 Upper cover 9 Motherboard

Claims (3)

A circuit board on which a high-frequency circuit is provided, a sheet metal shield frame that is formed in a frame shape having an opening and accommodates the circuit board, and a sheet metal that is fitted to the shield frame so as to close the opening. And a shield plate made of sheet metal for partitioning the internal space of the shield frame, the circuit board is grounded to the shield plate, and a part of the cover body is cut and raised to form the shield plate A high-frequency unit that is in contact with
The cover body includes a connection bar, a first tongue piece whose base end is one side edge of the connection bar, and a second tongue piece whose base end is the other side edge of the connection bar, The first and second tongue pieces respectively extend obliquely toward the circuit board and are in contact with the shield plate, and the first and second tongue pieces are formed so as to be swingable integrally. A high-frequency unit characterized by 2. The first tongue according to claim 1, wherein the cover body is a lower cover that closes a lower opening of the shield frame, and two adjacent leg portions of the shield plate penetrate the circuit board. A high-frequency unit, wherein the unit and the second tongue piece are individually in contact with each other. 3. The high frequency unit according to claim 1, wherein the first tongue piece and the second tongue piece have the same shape and size.

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