JP6250133B1 - Antenna device - Google Patents

Abstract

An antenna device having a complete electric shield structure for noise countermeasures, being inexpensive and excellent in mountability is obtained. A circuit board 1 provided with at least one antenna element 4a, a board case 3 for changing the radiation direction of radio waves of the antenna element 4a of the circuit board 1, a circuit board 1 and a board case 3, The circuit board 1 includes at least one end face made of a conductive member 1a, and the gasket 2 is disposed so as to cover the end face of the circuit board 1 and the circuit board 1 The substrate case 3 is disposed so as to cover the gasket 2 and is electrically connected to the gasket 2. [Selection] Figure 1

Description

  The present invention relates to an antenna device having an electric shield structure for noise countermeasures.

  As a countermeasure against noise in a device having an antenna, a liquid crystal panel is provided with a conductive gasket for sealing a gap between the conductive back cover of the liquid crystal panel and the metal casing in a notebook computer in which the liquid crystal panel is disposed inside the metal casing. A display module substrate on which the display driving circuit is mounted and an antenna substrate of a wireless communication antenna built in a personal computer are known (see Patent Document 1).

  The antenna module is disposed between the dome-shaped top cover, an antenna module that is housed in the top cover and receives radio waves, a bracket that covers the lower surface of the top cover, and the top cover and the bracket. An antenna device including a gasket that ensures sealing performance is known (see Patent Document 2).

JP 2011-82320 A JP 2010-259034 A

  Patent Document 1 discloses a gap between a conductive back cover of a liquid crystal panel and a metal housing in order to prevent noise radiated from a display drive circuit of the liquid crystal panel from adversely affecting the antenna characteristics of the wireless communication antenna. In order to prevent the light from the backlight of the liquid crystal panel from leaking, a light shielding tape is provided on the back side of the conductive back cover. Most of the conductive back cover and the conductive gasket are not in contact with each other. For this reason, conduction between the conductive back cover and the conductive gasket is not sufficient, and it is not perfect as a noise countermeasure. Further, in order to make the conductive back cover and the conductive gasket come into contact and conduct, there has been a problem that a notch portion must be provided in the light shielding tape, resulting in an increase in work man-hours.

  Further, the antenna substrate of the radio communication antenna is connected to the metal casing through a metal clip fitting provided near the side end portion thereof and grounded, and the antenna substrate of the radio communication antenna and the liquid crystal panel are connected to each other. An antenna cable for connecting to the display module substrate has to be wired, resulting in an increase in the number of components and an increase in cost.

  Patent Document 2 is an antenna device provided in a case of a narrow installation space such as a case of a door mirror of an automobile, and an antenna module arranged in an antenna case composed of a top cover and a bracket is exposed to wind and rain. The purpose is to ensure sealing so as to provide a waterproof function so as not to be exposed, and not to reduce noise radiated from the circuit board of the antenna.

  The present invention has been made to solve the above-described problems, and has an electric shield structure for noise countermeasures that is more complete than that of the conventional one, and is inexpensive and excellent in mountability. Is intended to provide.

  An antenna device according to the present invention electrically connects a circuit board provided with at least one antenna element, a board case for changing a radiation direction of radio waves of the antenna element of the circuit board, and the circuit board and the board case. The circuit board is formed of a conductive member at least one end face, and the gasket is disposed so as to cover the end face of the circuit board and is electrically connected to the conductive member of the circuit board. The board case is connected so as to cover the gasket and is electrically connected to the gasket.

  According to the present invention, it is possible to provide an antenna device that has a complete electrical shield structure for noise countermeasures, is inexpensive, and has excellent mountability as compared with the conventional one.

1 is an exploded perspective view of an antenna device according to Embodiment 1 of the present invention. It is a top view of the gasket which comprises the antenna apparatus which concerns on Embodiment 1 of this invention. It is a contact structure sectional view of an antenna device concerning Embodiment 1 of this invention. It is shield explanatory drawing of the antenna device which concerns on Embodiment 1 of this invention. It is a top view of the gasket which comprises the antenna apparatus which concerns on Embodiment 2 of this invention. It is shield explanatory drawing of the antenna device which concerns on Embodiment 2 of this invention.

Embodiment 1 FIG.
Hereinafter, an antenna device according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is an exploded perspective view of the antenna device, FIG. 2 is a plan view of a gasket that is a part of the antenna device, and FIG. 3 is a cross-sectional view of a contact structure of each part of the antenna device.
In FIG. 1, the antenna device mainly includes a circuit board 1, a gasket 2, and a board case 3.

  The circuit board 1 is a single-layer or multi-layer board formed of a base material such as glass epoxy resin. On the surface of the circuit board 1, an antenna board 4 on which a planar antenna element 4a such as a microstrip patch array for radiating radio waves to the space is formed is bonded. The element 4a emits radio waves to the space and receives incoming radio waves.

  Also, radio waves are generated on both sides or the back surface of the circuit board 1, and the generated radio waves are fed to the antenna element 4a of the antenna board 4, and the radio waves received by the antenna element 4a are amplified or distributed / combined. And various electronic components 9 (see FIG. 3) such as a microcomputer are mounted. Electrical connection between the electric circuit of the circuit board 1 and the antenna element 4a of the antenna board 4 is performed without using a cable or the like.

  The substrate case 3 is a casing component made of a conductive material such as ADC12 (aluminum material for casting) manufactured by a casting method such as aluminum die casting. The circuit board 1 is fixed to the board case 3 by being fastened to the board case 3 using fixing screws 5 at four corners.

Since the substrate case 3 directs the radiation direction of the radio wave radiated from the antenna substrate 4 in an arbitrary direction, the substrate case 3 is mechanically replaced with a mechanism (not shown) for directing an angle in an arbitrary direction instead of the antenna substrate 4. Driven by. Therefore, when the circuit board 1 is fixed to the board case 3, the attitude of the circuit board 1, that is, the antenna board 4 depends on the attitude of the board case 3. By controlling the attitude of the board case 3, the antenna The surface direction of the substrate 4, that is, the radiation direction of radio waves transmitted and received from the antenna element 4a can be controlled.
In the specification of the present invention, the description of the attitude control mechanism of the substrate case 3 is omitted since it is far from the essence of the invention.

  On the other hand, from various electronic components 9 such as a high-frequency circuit and a microcomputer mounted on the back surface of the circuit board 1, it is not originally intended separately from the radio waves that are intended to be radiated from the antenna board 4 into the space. Unwanted radio waves may be emitted. In addition, various electronic components 9 such as a high-frequency circuit and a microcomputer mounted on the back surface of the circuit board 1 may receive an originally unintended radio wave coming from the external space of the antenna device. As a countermeasure against such noise, various electronic components 9 such as a high-frequency circuit and a microcomputer mounted on the back surface of the circuit board 1 have a cavity structure of a ground conductor portion of the circuit board 1 and a recess formed in the substrate case 3. 6 can be shielded electrically.

  However, in the shield structure in this configuration, as shown in FIG. 1, the circuit board 1 is fastened to the board case 3 by fixing screws 5 that are fastened to fasten the board case 3 at the four corners of the circuit board 1. It ’s just that. Therefore, a gap is generated between the circuit board 1 and the board case 3 at the central part (other than the screw fastening part) of the four sides of the circuit board 1 that is not pressed by the fixing screw 5, and the machine as originally intended. There are cases in which even contact and even electrical contact (conduction) cannot be realized. In this case, since the above-described electrical shield structure cannot be formed between the circuit board 1 and the board case 3, the originally intended noise countermeasures cannot be realized, and the high frequency mounted on the back surface of the circuit board 1 is not achieved. Various electronic components 9 such as circuits and microcomputers emit unnecessary radio waves, and on the contrary, they may receive radio waves that are not originally intended.

In the antenna device according to the first embodiment of the present invention, the mechanical gap that inevitably occurs between the circuit board 1 and the board case 3 and the electrical opening caused by the gap are filled with a circuit. After the gasket 2 is sandwiched between the substrate 1 and the substrate case 3, the circuit substrate 1 is fastened to the substrate case 3 with fixing screws 5.
The gasket 2 is manufactured by a processing method such as press working, and is made of a metal sheet metal material having spring properties such as a stainless steel plate (SUS304), a galvanized steel plate (SECC), and a tin plated steel plate (SPTE). It is a member.

  As shown in FIG. 1, the gasket 2 is placed on a shelf 7 provided on the inner periphery of the substrate case 3, and the circuit board 1 is placed on the gasket 2. Further, the gasket 2 at the portion (four sides) sandwiched between the upper surface of the shelf 7 of the substrate case 3 and the back surface of the circuit board 1 is formed into an L-shape by press bending as shown in FIG. The formed bent portion 8 is formed intermittently over a plurality.

A front view of the gasket 2 is shown in FIG. 2, and a sectional view showing a stacked state of the gasket 2 and the circuit board 1 with respect to the substrate case 3 is shown in FIG. 3.
As shown in FIG. 3, the gasket 2 has a bent L-shaped structure in the cross section of FIG. This bent structure is formed by press working. Due to this L-shaped bent structure, the gasket 2 can increase the section modulus while having a thin plate structure, and can obtain the rigidity necessary for handling when manufacturing the parts and mounting the parts on the antenna device. .

The bent portion 8 which is the base of the L-shape has a plurality of spring structures using a restoring force as a metal elastic body, and the plurality of spring structures constituting the gasket 2 are a single metal material. Are formed integrally. The surface of the gasket 2 is plated with a conductive material.
Further, the vertical surface portion of the gasket 2 bent in an L-shape is attached to the side surface of the circuit board 1 to increase the shielding effect and to visually inspect that the gasket 2 has been mounted in the process. It becomes possible. Further, the top of the vertical portion of the gasket 2 bent into an L-shape positively protrudes from the surface of the antenna substrate 4, thereby affecting the formation of the radiation pattern of the antenna. It can also be used for suppressing unnecessary radiation of an antenna radiation pattern such as lobe suppression.

On the other hand, the antenna substrate 4 is bonded to the front surface of the circuit board 1, and on the back surface side of the circuit board 1, a ground portion 1 a is formed by a conductive member on the surface facing the shelf portion 7 of the substrate case 3. Therefore, it is considered that the ground portion 1a of the circuit board 1 and the board case 3 can be electrically connected via the conductive gasket 2. The ground portion 1a may be formed of a conductive member on at least one end face of the circuit board 1.
By electrically connecting the ground portion 1a of the circuit board 1 and the board case 3 using the gasket 2, the gap generated between the circuit board 1 and the board case 3 is filled with the gasket 2, so that Shielded.

  In particular, the bent portion 8 of the gasket 2 sandwiched between the circuit board 1 and the substrate case 3 has a plurality of spring structures using a restoring force as a metal elastic body. According to the amount of gap generated between the contact surface of the substrate case 3, electrical continuity between the two can be achieved with an appropriate amount of crushing, whereby mechanical contact and electrical contact (conduction) are achieved. Can be realized completely, and a thorough shielding effect can be obtained.

  Moreover, since the electronic component 9 mounted on the back surface of the circuit board 1 can be accommodated in the cavity structure 6 formed by the ground portion 1a of the circuit board 1 and the substrate case 3, these electronic components 9 It is possible to prevent radiated electromagnetic waves that have been radiated from the outside of the device from being radiated to the outside of the device, and to prevent receiving electromagnetic waves that are not intended to be received from outside the antenna device. .

Next, a mechanism for filling a mechanical gap between the circuit board 1 and the board case 3 and further filling an electrical opening, that is, how to obtain an electrical shield (shielding) will be described in detail. To do.
FIG. 4 shows a front view of the gasket 2 of the antenna device according to Embodiment 1 of the present invention, a cross-sectional view showing the relationship between the bent portion 8 of the gasket 2 and the electrical contact location obtained by the gasket 2.

In FIG. 4, the bent portion 8 of the gasket 2 is sandwiched between the circuit board 1 and the substrate case 3 and is crushed, as shown in the drawing, thereby causing a mechanical phenomenon generated between the circuit board 1 and the substrate case 3. Serves to fill gaps.
Thereby, mechanical and electrical contact can be obtained between the gasket 2 and the circuit board 1 and between the gasket 2 and the board case 3 by the bent portion 8 of the gasket 2.

In FIG. 4, the contact point obtained when the tip of the bent portion 8 of the gasket 2 pushes back the circuit board 1 is indicated by an upward arrow, and the contact point obtained when the base of the bent portion 8 of the gasket 2 pushes back the gasket 2 faces downward. Shown with an arrow.
By obtaining the contact points described above, the width W of the gaps formed between all the circuit boards 1 and the board cases 3 is set to ¼ wavelength or less of the free space wavelength of the radio wave for which transmission (leakage) is to be suppressed. Thus, it is possible to shield radio waves having a frequency equal to or higher than the frequency of radio waves for which transmission (leakage) is to be suppressed.
In addition, since it is desirable that the dimension of the width W is ideally 1/10 wavelength or less, it is possible to form the bent portion with a space as narrow as possible within the range of processing restrictions. desirable.

Embodiment 2. FIG.
Next, an antenna device according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 5 is a plan view of a gasket which is a partial component of the antenna device.
As shown in FIG. 5, the bent portion 10 of the gasket 2 used in the antenna device according to the second embodiment of the present invention has a T-shaped shape with the ends of the bent portion 10 extending to both sides. Since other configurations are the same as those of the antenna device of the first embodiment, description thereof is omitted.

Next, a mechanism for filling a mechanical gap between the circuit board 1 and the board case 3 and further filling an electrical opening, that is, how to obtain an electrical shield (shielding) will be described in detail. To do.
FIG. 6 shows a front view of the gasket 2 of the antenna device according to Embodiment 2 of the present invention, a cross-sectional view showing the relationship between the bent portion 10 of the gasket 2 extending on both sides, and the electrical contact location obtained by the gasket 2. .

  In FIG. 6, the bent portion 10 of the gasket 2 is sandwiched between the circuit board 1 and the substrate case 3 and is crushed as shown in FIG. Serves to fill gaps. Thus, as in the first embodiment, mechanical and electrical contact can be obtained between the gasket 2 and the circuit board 1 and between the gasket 2 and the board case 3 by the bent portion 10 of the gasket 2.

A contact point obtained when the tip of the bent portion 10 of the gasket 2 pushes back the circuit board 1 is indicated by an upward arrow, and a contact point obtained by the root of the bent portion 10 of the gasket 2 pushing back the gasket 2 is indicated by a downward arrow.
In the second embodiment, the bent portion is formed at a narrower distance than the bent portion 8 used in the first embodiment by forming the tip of the bent portion 10 of the gasket 2 in a T shape extending to both sides. Therefore, a higher suppression amount of electrical shielding performance can be obtained. In addition, even with the same amount of suppression, it is possible to obtain a shielding performance that can suppress transmission of radio waves of higher frequencies.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments, and various design changes can be made. Within the scope of the present invention, each embodiment is described. These embodiments can be freely combined, and each embodiment can be modified or omitted as appropriate.

1: circuit board, 2: gasket, 3: board case, 4: antenna board,
4a: antenna element, 5: fixing screw, 6: cavity structure, 7 shelf,
8: L-shaped bent part, 9: Electronic component, 10: T-shaped bent part

Claims (8)

  A circuit board provided with at least one antenna element, a board case for changing the radiation direction of the radio wave of the antenna element of the circuit board, and a conductive material for electrically connecting the circuit board and the board case The circuit board is provided with a conductive member at least one end face of the circuit board, and the gasket is disposed so as to cover the end face of the circuit board and is electrically connected to the conductive member of the circuit board. The antenna case is characterized in that the substrate case is disposed so as to cover the gasket and is electrically connected to the gasket.   The antenna device according to claim 1, wherein the gasket is made of metal and has a plurality of spring structures using a restoring force as a metal elastic body.   The antenna device according to claim 2, wherein a plurality of spring structures constituting the gasket are integrally formed of a single metal material.   4. The antenna device according to claim 2, wherein a surface of the gasket is plated with a conductive material.   5. The antenna device according to claim 2, wherein the gasket has an L-shaped structure in which a sectional structure of the gasket is bent.   6. The antenna device according to claim 5, wherein the vertical portion of the L-shaped structure of the gasket is configured to protrude from a surface of the circuit board on which the antenna element is provided.   The antenna device according to any one of claims 2 to 6, wherein a spring structure constituting the gasket forms an L-shape.   The antenna device according to any one of claims 2 to 6, wherein the spring structure constituting the gasket forms a T-shape.

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