JP2008034711A - GND structure of substrate - Google Patents

Abstract

To provide a GND structure of a substrate with improved adhesion between the substrate and a chassis.
In a GND structure of a substrate, a substrate is disposed between a chassis and a frame, the frame is fixed to the chassis, and the chassis and the substrate are grounded. A pressing screw 10 that presses the substrate 7 to bring the substrate 7 into close contact with the chassis 5 is screwed into the frame 8.
[Selection] Figure 2

Description

  The present invention relates to a ground (GND) structure of a substrate in an LNB converter or the like provided in an antenna for satellite broadcasting or the like.

  As an LNB (Low Noise Block-down) converter for receiving satellite broadcast / satellite communication, for example, the one described in “FIG. 14” of Patent Document 1 (Japanese Patent Laid-Open No. 2005-197852) is known.

  According to the known technique disclosed in Patent Document 1, radio waves from a satellite are received by an antenna installed outdoors. The radio waves are reflected on the surface of the parabona antenna, collected on the feed phone, and sent to the LNB converter. The signal frequency-converted by the LNB converter is transmitted to an indoor tuner after passing through the coaxial cable. The video is displayed on the television receiver by the output of the tuner.

  This LNB converter includes a first divided cabinet and a second divided cabinet as a casing. An external waveguide is connected to the surface of the first division cabinet, and a feed phone is formed at the tip of the external waveguide. The antenna is formed so that the radio wave reflected from the surface is focused inside the feed phone. The collected radio waves are sent to the LNB converter through the external waveguide. Inside the LNB converter, a receiving circuit for converting the frequency of incoming radio waves is formed on a substrate, and the output side of this receiving circuit is connected to a connector.

  The housing is formed by fixing the first divided cabinet and the second divided cabinet with fixing claws. The fixed claw is formed in the second divided cabinet. Ribs are formed in the second divided cabinet at regular intervals. The rib portion is formed in a flat plate shape whose main surface is perpendicular to the longitudinal direction of the second divided cabinet. The rib portion is formed with a recessed portion whose cross-sectional shape is a semicircular cutout portion. A chassis is disposed in the recess so as to follow the shape of the recess. A waveguide for passing radio waves is formed inside the chassis. The waveguide is disposed so as to be substantially coaxial with the housing.

In the chassis, a frame and a substrate are fixed with screws on the first divided cabinet side. A receiving circuit is formed on the upper surface of the substrate.
Japanese Patent Laying-Open No. 2005-197852 (FIG. 14)

  The conventional LNB converter has a structure in which the chassis and the substrate are brought into close contact with each other by placing the substrate on the chassis, covering the frame, and tightening with screws, thereby obtaining a ground (GND).

  However, the flatness of the GND surface of the chassis and the flatness of the GND surface of the frame are distorted, and there is a possibility that a portion that is not in close contact is generated.

  Further, in the structure in which the chassis and the substrate are brought into close contact with each other by tightening with screws, a space for the fastening portion is required, and the overall product size has to be increased.

  An object of the present invention is to provide a GND structure of a substrate that solves the above problems.

  In order to achieve the above object, the present invention has taken the following measures. That is, the present invention is characterized in that a substrate is disposed between a chassis and a frame, the frame is fixed to the chassis, and the chassis and the substrate are grounded. A pressing screw that presses the board and attaches the board to the chassis is screwed to the frame.

It is preferable that the tip of the pressing screw that comes into contact with the substrate is formed in a curved surface.
Further, the tip of the pressing screw that contacts the substrate can be formed on a flat surface.

  According to the present invention, the board can be brought into close contact with the chassis by the pressing screw screwed into the frame.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of an LNB converter to which the present invention is applied, and FIG. 2 is an exploded perspective view thereof. In FIG. 2, “enclosure” is not shown.

  In the LNB converter, a housing 3 is formed by a first divided cabinet 1 and a second divided cabinet 2. The housing 3 is formed by fixing a first divided cabinet 1 and a second divided cabinet 2 with fixing claws 4. A chassis 5 is held inside the housing 3. A horn cap 6 is provided at the tip of the chassis 5. The horn cap 6 protrudes from the housing 3.

  A substrate 7 is placed on the chassis 5. The substrate has a rectangular shape. A frame 8 is placed on the substrate. The frame 8 is fixed to the chassis 5 with screws 9 at the four corners of the peripheral edge thereof. When pressed by the frame 8, the chassis 5 and the substrate 7 are brought into close contact with each other to take GND.

  In the present embodiment, the chassis 5 and the substrate 7 are not evenly adhered to the entire surface with only the screws 9 at the four corners. Therefore, the pressing screw 10 that presses the substrate 7 and adheres the substrate 7 to the chassis 5 is provided. The frame 8 is screwed.

  The position where the pressing screw 10 is disposed is a position suitable for bringing the substrate 7 into close contact with the chassis 5. The number and arrangement position are not particularly limited.

  In the embodiment shown in FIG. 2, the pressing screw 10 is disposed at a position where the rear surface of the hatched portion of the substrate 7 is in close contact with the chassis 5. That is, a screw hole 11 for screwing the pressing screw 10 into the position is formed in the frame 8.

  FIG. 3 shows a structure for preventing the pressing screw 10 from loosening. As shown in FIG. 3A, a locking agent 12 is applied to the outer peripheral surface of the pressing screw 10. Then, as shown in FIG. 2B, the pressing screw 10 to which the locking agent 12 is applied is screwed into the screw hole 11 of the frame 8, and then the adhesive 13 is applied to the protruding portion of the pressing screw 10. Further, as shown in FIG. 3C, a silicon sealant 14 is applied on the adhesive 13.

  The frame 8 is provided with a peripheral wall 15 that forms a reservoir for the adhesive 13 and the silicone sealant 14 around the screw hole 11.

  In the embodiment shown in FIG. 1, the tip 16 of the pressing screw 10 that contacts the substrate 7 is formed in a curved surface. By forming the curved surface, the surface of the substrate 7 is hardly damaged.

  4, the tip 16 of the pressing screw 10 that contacts the substrate 7 is formed on a flat surface. Other configurations are the same as those shown in FIG. By making the tip 16 of the pressing screw 10 flat as described above, the ground contact area of the screw is increased, and the adhesion of the substrate 7 can be further improved.

  The tip shape of the pressing screw 10 is not limited to the above-described one, and may be any shape suitable for close contact.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

It is sectional drawing of the LNB converter concerning embodiment of this invention. FIG. 2 is an exploded perspective view of the converter of FIG. 1 (however, the housing is not shown). It is explanatory drawing which shows the locking structure of a press screw. It is sectional drawing which shows an example of the shape of the front-end | tip part of a press screw.

Explanation of symbols

  5 Chassis, 7 Substrate, 8 Frame, 10 Press screw, 16 Tip.

Claims (3)

In the GND structure of the substrate, the substrate is disposed between the chassis and the frame, the frame is fixed to the chassis, and the chassis and the substrate are grounded.
A GND structure of a substrate, wherein a pressing screw for pressing the substrate and bringing the substrate into close contact with the chassis is screwed into the frame.   2. The substrate GND structure according to claim 1, wherein a tip of the pressing screw that contacts the substrate is formed in a curved surface.   2. The substrate GND structure according to claim 1, wherein a tip of the pressing screw that contacts the substrate is formed on a flat surface.

Images