JPH03289013A - Shielding structure of lighting switch - Google Patents

Abstract

PURPOSE:To shield the access of electromagnetic waves and lead light inside equipment to a key pad for emission to the outside by providing a light transmitting member with a shielding member that a conductive member is formed in meshes. CONSTITUTION:A flexible light-transmitting shielding member 20 that a conductive member 22 connected to earth potential is formed in meshes is provided between a key pad 4 and a printed wiring board 11. In this way, the shielding member 20 has the conductive member 22 formed in meshes to prevent the access of electromagnetic waves, and light from a light source is leaked from the empty portions of the meshes through the light transmitting member to allow the lighting of the key pad 4 sufficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a shield structure for electromagnetic wave countermeasures for an illuminated switch installed in an electronic device.

(Prior Art) Illuminated switchgears, which allow switch operations to be performed even at night, are used in various electronic devices, and are particularly frequently used in portable radio devices. A conventional portable radio device will be explained using FIGS. 7 and 8. In Figure 7, the portable wireless device (1) is provided with an illuminated switch (3), so that it can be operated while being carried, especially at night. At the land price end there is a transmitter (5),
A receiver section (7) is provided, and a display section (9) is further provided between the receiver section (7) and the illuminated switch (3).

and the illuminated switch (3) has multiple keys h as shown in Figure y.
, a keypad (4) made of a translucent resin integrally formed with a tab (4a), and a contact portion (6) provided corresponding to each key top. The keypad (4) is located in the housing hole (1).
a). Although the contact portion (6) is not shown in detail, it consists of a movable contact portion and a fixed contact portion in which a conductive portion is provided in a transparent resin. The movable contact moves in response to the movement of the key top (3a), and the fixed contact makes. In addition to various electronic components, a light source (13) consisting of a VcLED is mounted on the printed wiring board (11). The light from this light source passes through the contact portion (6) and the keypad (4) and is emitted to the outside, so that the keypad (4) is illuminated.

Many of these portable radios use high frequencies and are equipped with electromagnetic wave countermeasures. For example, if the casing is made of resin, it may be plated with plastic or coated with conductive paint. However, the seventh factor is that in a radio device in which most of the keypad (4) protrudes from the hole in the housing, such as the portable radio device shown in Fig. 8, the entire surface of the keypad (4) is plated or This method could not be used because if paint was applied, light could no longer be emitted to the outside.

! %, the higher the frequency used by the radio, the higher the frequency would penetrate through the bad (4) and cause malfunctions.

(Problem to be Solved by the Invention) As mentioned above, in an illuminated switch that is used by illuminating the keypad, if the entire surface of the keypad itself is coated with shielding plating or conductive paint, the keypad cannot be illuminated. Therefore, in the conventional illuminated switch, there is a problem in that electromagnetic waves enter and exit at the keypad.

The present invention has been made to solve the above-mentioned drawbacks, and an object of the present invention is to provide a shield structure for an illuminated switch that blocks electromagnetic waves and allows backlight light to be emitted to the outside through a keypad.

The structure includes a flexible light-transmitting member in which a conductive member connected to a ground potential is formed into a mesh shape and is provided between the keypad and the printed wiring board.

The shield structure of the illuminated switch according to the second aspect of the invention is constructed by forming a conductive member connected to a ground potential on a keypad.

(Function) In the first invention, since the conductive member is formed in a mesh shape in the shield member, it is possible to prevent electromagnetic waves from entering and exiting. Additionally, light from the light source also leaks through the transparent member from the empty portion of the mesh, allowing the keypad to be illuminated.

In the second invention, since the conductive member is formed in the shape of a mesh on the keypad itself, it prevents electromagnetic waves from entering and exiting, and also radiates light from the empty part of the mesh to the outside through the keypad that has translucency. This enables illumination.

(Example) A first embodiment of the present invention will be described using the drawings.

As shown in FIG. 1, a printed wiring board (11) mounted on a radio housing (not shown) and a light source (13) consisting of a KLED
is installed. This printed wiring board (11) [contact portions (24) are provided in an overlapping manner. As shown in FIG. 2, the contact part (24) includes a movable contact board (24a), a spacer board (24b), a fixed contact board (24C), and a reinforcing plate (
15). On one side of the movable contact substrate (24a), the movable contact is made of a conductive member and is provided on a transparent substrate made of polyester. Spacer substrate (24b)
It also consists of a transparent substrate and is provided with a plurality of holes, which holes are arranged at positions corresponding to the movable contacts. Fixed contact board (
24C) also has fixed contacts (not shown) provided on a transparent substrate, and these fixed contacts are arranged at positions corresponding to the movable contacts. The reinforcing plate (15) is made of transparent resin, and is provided to attach the contact portion (24) to the printed wiring board (work 1), and is also provided to secure mounting space for other components (not shown). . (24d) shown in FIG. 1 is a flexible board that is connected to and read by the fixed contact board (24C) and is used for conductive signals of the contacts.

A shield member (20) is provided to cover the thus formed contact portion (24).

As shown in FIGS. 1 and 3, the shield member (20) is
It is constructed by applying a conductive member (22) in a mesh shape to a transparent and flexible cover coat (21) made of polyester. The conductive member (22) consists of a copper pattern, and one cover coat (21) V as shown in FIG.
It is formed by C etching treatment and is sandwiched between the other cover coat (21). The squares in mesh are 1/20 to 1/10 of the frequency used by the radio.
It is a regular rectangle with a length up to 0. Shield member (
The conductive member (22) of 20) is connected to the printed wiring board (11 oki 7
−． 1. It is arranged on the hatan (lla). The housing (2) provides a flexible cover coat (21).
is pressed toward the earth pattern (lla) to improve conduction between the column member (22) and the earth pattern (11a).

With this configuration, even when the light source (13) is turned on, this light leaks from the empty part of the mesh and is guided outside through the keypad (4), so that the switch cannot be illuminated. It becomes possible to do so. In addition, since the conductive member is applied in a mesh shape, the printed wiring board (11)
It can block electromagnetic radiation from other electronic components mounted on the device. It can also prevent electromagnetic waves from entering from outside. In particular, electromagnetic waves emitted by devices with a high mantissa band, such as mobile radio telephones, can easily infiltrate other devices and cause malfunctions, so it is very effective to be able to block the radiation of electromagnetic waves. Furthermore, since a flexible material is used as the base material of the shield member, when pressed down by the casing, the shield member comes into close contact with the ground pattern, allowing for good conduction.

Further, because of its usability, it is easy to manufacture products of various shapes, so that the structure of the key switch can be applied to any case.

Further, due to the flexibility of the shield member, the shield member is bent in response to the pressing operation of the key top, and the disc spring is pressed.

Next, a second embodiment will be explained with reference to FIG.

The configuration of the shield member (20) is the same as that of the first embodiment, but in this example, a reinforcing plate (15) and a printed wiring board (11) are used.
will be placed between the The side part (2) of the shield member (20)
0a) is disposed between a recess (2a) provided in the housing (2) and a printed wiring board (11). From the housing (2) to the ground pattern side of the printed wiring board (11)
The conductive member 20) is pressed and conduction is improved. This configuration allows the printed wiring board (11) to block electromagnetic waves emitted from various electronic components mounted thereon and to block electromagnetic waves from the outside.

Next, a third embodiment will be explained using FIGS. 5 and 6.

Here, a mesh-like conductive member (28) is formed on the entire back surface of the keypad (4) and the peripheral edge of the front surface. On the other hand, the inner surface of the casing (2) is coated with conductive paint or the like to form a ground potential. Then, the flexible contact board (2
A receiving portion (24a2) is formed at the periphery of 4a).

This allows the receiving part (24a2) of the movable contact board (24a) to
A conductive member (28) at the periphery of the keypad (4) is pressed to the side by the housing (2). Therefore, the conductive member (
28) is in close contact with the casing (2), so that grounding is ensured. In this example as well, the light from the light source (13) passes through the empty part of the mesh and is emitted to the outside through the keypad (4). Furthermore, compared to the first and second embodiments, there is no need to provide a separate member as a shield member, so the thickness of the device can be made thinner.

In addition, in the first, second, and third embodiments, the conductive member is constructed of a copper pattern, but is not limited to this, and may be constructed by applying a conductive paint or pasting a four-conductor tape. Good too.

In addition, in the shield members of the first and second embodiments, both end sides are not covered as shown in FIG. 1, but the directivity of the radiated electromagnetic waves and the incoming electromagnetic waves are mainly perpendicular to the printed wiring board. Since it can be strongly attacked in any direction, it is sufficient to protect against electromagnetic radiation.

In addition, even if the structure is completely shielded by providing enclosures on both ends to completely eliminate the intrusion of electromagnetic waves from the outside,
Of course, the same functions and effects as in the above embodiment can be achieved.

〔Effect of the invention〕

As explained above, in the shield structure of the lighted switch according to the first invention, the shield member in which the conductive member is formed into a mesh shape is provided on the light-transmitting member, so that it is possible to block the ingress and egress of electromagnetic waves, and also to prevent the inside of the device. light can be guided to the keypad and emitted to the outside. Furthermore, since the shield member is flexible, it can be easily manufactured into various shapes and can be applied to any key switch structure.

In the shield structure of the illuminated switch according to the second invention, the conductive member is formed in a mesh shape on the keypad itself, so that electromagnetic waves can be blocked from entering and exiting, and light inside the device can also be radiated from the keypad to the outside.

Furthermore, since the conductive member is provided on the keypad itself, the thickness of the device can remain the same.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing the first embodiment of the present invention, Fig. 2 is a sectional view of the first embodiment, Fig. 3 is a detailed view of section A in Fig. 2, and Fig. 4 is a detailed view of section A in Fig. 2. 5 is a sectional view of the third embodiment, FIG. 6 is a detailed view of section B in FIG. 5, FIG. 7 is a conventional example, and FIG. 8 is a section C of FIG. 7. -C sectional view.

Claims (3)

[Claims] (1) A keypad made of a translucent material, a printed wiring board provided with a light source for illuminating the keypad, and a conductive wire provided between the keypad and the printed wiring board and connected to ground potential. 1. A shield structure for an illuminated switch, characterized in that the flexible member comprises a flexible translucent member and a shield member formed in a mesh shape. (2) It is characterized by comprising a keypad made of a translucent material and in which a conductive member connected to a ground potential is formed in a mesh shape, and a printed wiring board provided with a light source that illuminates the keypad. Shield structure of illuminated switch. (3) The shape of the mesh formed by the conductive member is a regular square whose length is 1/20 to 1/100 of the frequency of the electronic device in which the light switch is installed. (2) A shield structure of the illuminated switch according to any one of the above.