JPH0334012Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a switching panel structure that displays a liquid crystal display by operating a push button.

Switching panels driven by push button switches are widely used in electronic devices such as desktop calculators and line encryption devices. As this display means, a liquid crystal display is adopted because of its simple structure, thinness, and small size.

At this time, it is desired that malfunctions do not occur due to external radio noise.

[Conventional technology]

As shown in the perspective view of FIG. 2, the cross-sectional view of the main part of FIG. 3a, and the perspective view of the main part of FIG. , a surface plate 2 made of a metal plate is attached.

An elongated rectangular button window frame 3 is provided on the surface plate 2, and push buttons 4 made of an insulator such as synthetic resin are arranged in parallel on the button window frame 3. Further, the surface plate 2 is provided with an elongated rectangular display window 5 above the button window frame 3, facing a liquid crystal display 6, which will be described later. There is.

On the other hand, a printed board 7 is mounted inside the casing 1 in close proximity to and parallel to the surface plate 2. A switch key 8 is mounted on the printed board 7 facing each push button 4, and a liquid crystal display 6 is mounted facing the display window 5.

The switch key 8 is composed of a movable contact 9 and a contact pattern 11 formed on the surface of the printed board 7.

The movable contact 9 is a resilient, highly conductive thin metal plate formed in the shape of a tongue, and its base portion is connected to a land 10 formed at the end of a desired circuit pattern.
For example, it is fixed to the surface of the printed board 7 by soldering. The other end of the movable contact 9 projects in the direction of the push button 4 and is always in elastic contact with the bottom surface of the push button 4 to press the push button 4 against the frame edge of the button window frame 3.

Therefore, when the pushbutton 4 is pressed, the movable contact 9 comes into contact with the contact pattern 11 and turns on, activating the switching panel. Then, it is displayed on the liquid crystal display 6. Note that when the finger is released from the push button 4, the push button 4 returns to its original position due to the elasticity of the movable contact 9.

[Problem that the invention attempts to solve]

However, the conventional switching panel described above has a problem in that radio waves from the outside enter the housing 1 through the display window 5 and the button window frame 3, causing the switching panel to malfunction.

[Means for solving problems]

The above-mentioned problems with the conventional method include the front panel of the casing where the display window and push buttons are arranged side by side, the metal mesh spread on the back of the front panel and grounded to the casing, and the back of the metal mesh. The present invention comprises a transparent film spread over a transparent film, and a printed board mounted behind the transparent film and mounted with a switch key facing the push button and a liquid crystal display facing the display window, respectively. This is solved by the switching panel structure.

[Effect]

According to the above-mentioned means of the present invention, since the metal mesh is spread on the back surface of the top plate, the internal circuits of the printed board etc. are shielded. Therefore, radio noise does not enter and there is no risk of malfunction.

In addition, since a transparent film is sandwiched between the metal mesh and the printed board, there is no risk that the switch key and the circuit of the printed board will be shorted due to contact with the metal mesh, and since the shield body is a metal mesh, the liquid crystal It does not interfere with viewing the display.

〔Example〕

The gist of the present invention will be specifically explained below with reference to illustrated embodiments. Note that the same reference numerals indicate the same objects throughout the figures.

FIG. 1 is a perspective view showing an embodiment of the present invention in an isolated form, in which a metal mesh 20 whose periphery is grounded to the casing 1 is spread on the back surface of the top plate 2. . The metal mesh 20 is made of, for example, 90 meshes of steel wire with a diameter of 0.1 mm. Further, an insulating transparent film 21 is spread on the back surface of the metal mesh 20.

Furthermore, behind the transparent film 21, the transparent film 21 is in close contact with the surface of the printed board 7.
is installed.

As described above, the present invention includes a metal mesh 20 and a transparent film 21 between the surface plate 2 and the printed board 7.
are sandwiched, so that the tip of the movable contact 9 is pressed against the bottom end surface of the push button 4 via the metal mesh 20 and the transparent film 21.

Therefore, when the pushbutton 4 is pressed, the movable contact 9 comes into contact with the contact pattern 11 and turns on, activating the switching panel. Then, it is displayed on the liquid crystal display 6. In this case, since the metal mesh 20 is in contact with the printed board 7 via the transparent film 21, the pattern circuit of the printed board 7 will not be short-circuited.

Further, when the push button 4 is released from the finger, the push button 4 returns to its original position due to the elasticity of the movable contact 9, as in the conventional case.

A metal mesh 20 is spread behind the surface plate 2, which prevents external radio waves from entering from the surface plate 2 side, preventing malfunction. Since the mesh 20 is used, visibility of the display on the liquid crystal display 6 is not obstructed.

Furthermore, since the entire rear surface of the top plate 2 is shielded by the metal mesh 20, the top plate can be made of a synthetic resin plate with a good appearance at low cost.

[Effect of idea]

As explained above, the present invention has excellent practical effects such as there is no risk of external radio waves entering from the front panel side, the switching panel does not malfunction, and the configuration is simple. There is.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention shown in separated form, FIG. 2 is a perspective view of a conventional switching panel, and FIG. 3 is a perspective view of a conventional switching panel.
is a sectional view of the main part, and (b) is a perspective view of the main part. In the figure, 1 is a housing, 2 is a front plate, 3 is a button window frame, 4 is a push button, 5 is a display window, 6 is a liquid crystal display, 7 is a printed board, 8 is a switch key, 9 is a movable contact, 10 11 is a land, 11 is a contact pattern, 20 is a metal mesh, and 21 is a transparent film.

Claims (1)

[Scope of utility model registration request] A front panel of a housing on which display windows and push buttons are arranged side by side, a metal mesh spread on the back side of the front board and grounded to the housing, and a transparent film spread behind the metal mesh. A switching panel structure comprising: a switch key mounted behind the transparent film and facing the push button; and a printed board facing the display window and having a liquid crystal display mounted thereon.