JPH0766362B2 - Electronics - Google Patents

Description

The present invention relates to an electronic device, and more particularly to an electronic device that secures the rigidity of the device by a laminated structure of constituent members with a reinforcing plate interposed.

[Prior Art] There is a remarkable reduction in the size and weight of devices such as electronic desk calculators (hereinafter referred to as calculators) and electronic translators, and in recent years, card-type devices have become common.

[Problems to be Solved by the Invention] Thus, the small-sized and lightweight device is taken out to all environments due to its good portability and used under a wide range of conditions. Therefore, it is necessary to take measures against electrostatic discharge as well as environmental resistance related to temperature and humidity.

For example, circuit elements such as MOS semiconductors used for power saving are vulnerable to static electricity, and static electricity accumulated in the human body, clothes, etc. during operation is destroyed by discharging through the keyboard, or in the case of memory etc. Causes problems such as changes in stored data. Therefore, it is necessary to connect the metal member in the device, which easily attracts static electricity, to the ground potential of the circuit.

Such a grounding member can be easily mounted in a miniaturized device, and can secure a stable connection against bending, twisting, and impact applied to the device without increasing the size of the entire device. Must.

[Means for Solving Problems] In order to solve the above problems, in the present invention, a flexible film-like mounting sheet having a key symbol formed on a keyboard portion and a contact state with the mounting sheet are provided. A first reinforcing plate which is provided and is made of a conductive elastic member for protecting the electronic element; and a conductive second reinforcing plate which covers the lower surface of the device and maintains the strength of the entire device. An elastic tongue portion formed on the first reinforcing plate and having a tip bent in a direction of the second reinforcing plate, and arranged between the first reinforcing plate and the second reinforcing plate, and a circuit pattern. And a tongue piece provided on a part of the printed circuit board at a position corresponding to the elastic tongue and having a circuit pattern connected to the ground potential of the printed circuit board on the upper and lower surfaces thereof. And having the first With tongue portion of the reinforcing plate presses the tongue upper surface of the printed circuit board by contacting the tongue piece lower surface to the second reinforcing plate, wherein the first reinforcing plate and the second
The reinforcing plate was simultaneously connected to the ground potential of the printed circuit board.

[Operation] A metal reinforcing plate 3 is inserted into the frame 2 in FIG. 1, and a tongue portion 3F ′ provided on the flange of the reinforcing plate 3 is inserted.
Presses the tongue piece 6b having the ground pattern of the circuit board 6 downwardly at the time of stacking to bring it into contact with the metal reinforcing plate 7. As a result, static electricity from the operation surface of the cover sheet 1 is guided to the ground potential without affecting the circuit elements. Further, since the reinforcing plate 7 functions as an electrostatic shield plate, it is possible to prevent accidents such as element destruction and data destruction due to static electricity.

[Examples] Hereinafter, the present invention will be described in detail based on examples shown in the drawings.

FIG. 1 is an exploded perspective view showing the structure of a thin calculator as an example of the electronic device according to the present invention. By stacking the illustrated members, a card-like calculator having the appearance as shown in FIG. 2 is obtained.

First, the exterior will be described. As shown in FIG. 2, a keyboard K including a plurality of numerical keys and calculation keys is formed on the surface of the calculator. In front of the keyboard K, a display unit D including an LCD for visually displaying input results and calculation results, and a solar cell unit B for supplying power to circuits in the device are arranged.

The surface of the device of FIG. 2 consists of a cover sheet 1 designated by the reference numeral 1 in FIG. The cover sheet 1 is formed by printing the key symbol 1K of the keyboard K on a flexible film material such as polyester, polycarbonate, vinyl chloride, and urethane having good light transmission. Display section
The portions corresponding to D and the solar cell portion B are not printed, and are transparent portions 1D and 1B that make the most of the transparency of the material.

A frame 2 formed by integrally molding an insulating plastic is arranged under the cover sheet 1. As shown in FIG. 3, a reinforcing plate 3 made of a thin metal plate is insert-molded on the frame 2. A key input portion 2K is formed at a position corresponding to the key symbol 1K on the cover sheet 1.

Inner key top in the center of the 2K circular hole
2K 'is located, the upper surface of the inner keytop 2K' is substantially level with the upper surface of the frame 2, and the inner key top 2K 'is integrally formed with the main body by a plurality of thin arms 2K ".
Therefore, when the portion of the key symbol 1K of the cover sheet 1 attached to the upper surface of the frame 2 is pressed, the film of the cover sheet 1 bends downward, the upper surface of the inner key top 2K 'is pressed, and the arm 2K "elastically deforms. It is a structure that is displaced downward in parallel.

The amount of displacement of the inner key top 2K1 'can be adjusted to the desired value by adjusting the length, thickness and width of the arm 2K ", but the desired operation stroke and load can be obtained. The molding material flows into the 2K ′ part through the arm 2K ″ part, so it is necessary to set the dimensions of the arm 2K ″ so that short-molding does not occur. Stroke and small operation load are obtained.

As the material of the frame 2, a resin such as polycarbonate, styrene, or polypropylene may be used.

On the other hand, the reinforcing plate 3 to be inserted has an outer shape formed from a metal having high rigidity and elasticity such as stainless steel, phosphor bronze, or brass by etching or pressing. The outer shape before insertion is as shown in FIG. An L-shaped flange 3F is formed on the outer periphery of the reinforcing plate 3 toward the lower surface of the calculator. This flange portion is embedded in the resin of the frame 2 at the time of insertion to improve the rigidity of the entire frame and increase the resistance against twisting and bending. Square hole 3D, 3
B is a window for allowing the display 10 and the solar cell 9 arranged below to face the outer surface of the device. The flange 3F is cut out on the outer periphery near the square hole 3B, and the tongue is cut by bending.
3F 'is formed. The tongue portion 3F 'is for dropping the frame 2 to the ground potential of the circuit, and is exposed from the square hole 2H provided at the corresponding position. The frame 2 and the reinforcing plate 3 shown in FIG. 3 are flush with the upper surface thereof, and the reinforcing plate 3 is in direct contact with the back surface of the covering sheet 1 when laminated.

Below the frame 2, a flexible contact sheet 4 having a printed pattern serving as a key movable contact formed on the lower surface is arranged. The contact sheet 4 is formed by printing a contact pattern 4a on a thin film such as a polyester film using a conductive ink such as carbon paste at a position corresponding to a key input portion of the frame 2.

This contact pattern 4a is pushed by the inner key top 2K 'of the frame 2 and is displaced downward to form a circular hole in the insulating spacer 5.
The fixed contact 6a on the upper surface of the printed circuit board 6 arranged opposite to the contact 5a is contacted. Key input is performed by short-circuiting the fixed contact 6a due to the contact between these contacts.

An LSI 8 forming an arithmetic circuit is mounted on the printed circuit board 6, and a key input signal is guided to the LSI 8. The LSI 8 performs an operation according to the input, outputs the result or an intermediate result to the display device 10 and is visually displayed. The drive signal of the display 10 is given via the heat seal connector 11. Since the LSI 8 and the display 10 are operated by the weak current supplied from the solar cell 9 through the heat seal connector 11,
I8 is a C-MOS type, and the display 10 is an LCD (liquid crystal display) to reduce power consumption.

Further, a tongue piece 6b formed by cutting out the board with a U-shaped slit is formed at a position corresponding to the tongue portion 3H of the frame 2 of the printed circuit board 6, and the tongue portion 3H and the contact sheet 4 are formed.
And the insulating spacer 5 face each other through the cutout portions 4b and 5b. A pattern connected to the ground potential of the circuit is formed on both sides of the tongue piece 6b.

From the bottom surface of the printed circuit board 6, a relatively thick metal reinforcing plate 7 is adhered and fixed to the frame 2 with an adhesive 7a to hold the contact sheet 4, the insulating spacer 5, and the printed circuit board 6 and The laminated structure is completed. At this time, the tongue portion 3F 'of the frame 2 pushes down the tongue piece 6b of the circuit board 6 and contacts the portion 7b of the lowermost reinforcing plate 7 on which no adhesive is applied, whereby the reinforcing plate 7 and the frame 2 are The reinforcing plate 3 is connected to the ground potential of the circuit.

FIG. 5 is a view of the cross section taken along the line XX of FIG. 2 as seen in the direction of the arrow. As shown in the figure, the tongue portion 3F 'of the reinforcing plate 3 inserted in the frame 2 has a printed circuit board 6 due to its elastic force.
The tongue piece 6b is displaced downward and brought into contact with the reinforcing plate 7.

With such a structure, since the reinforcing plate 3 is dropped to the ground potential of the circuit, static electricity transmitted from the surface of the mounting sheet at the time of operation can be released to the metal reinforcing plate 3 and the circuit to the ground potential. It is possible to prevent application to the display 10 or a circuit network including the LSI 8. Also, the reinforcing plate 7
Are installed in the same manner, an electrostatic shield effect can be obtained, and a higher protection effect can be realized.

In addition, the reinforcing plate 3 whose rigidity is increased by the flange 3F,
Since the solar cell 9 is surrounded by the relatively thick reinforcing plate 7 as shown in FIG. 5, the entire calculator is twisted,
Even when stress such as bending is applied, deformation is unlikely to occur, and the solar cell 9 made of a material such as a silicon wafer or a glass plate which is easily damaged can be protected.

Similarly, as shown in FIG. 6 (a view of the section taken along the line Y-Y in FIG. 2 in the direction of the arrow), the display 10 is also surrounded by the reinforcing plates 3 and 7, and the display 10 is impossible. It doesn't work. This structure is effective when using an easily damaged display such as an LCD that holds a liquid crystal by a glass plate.

FIG. 7 shows a cross section taken along line ZZ of FIG. 2 as seen in the direction of the arrow. When the cover sheet 1 is pressed, the inner key tops 2K 'are displaced downward through the sheet, the contact sheet 4 is brought into contact with the printed circuit board 6, and the contact pattern 4b is formed.
By short-circuiting the fixed contacts 6a, 6a, key input is performed. As described above, the arm 2K ″ that holds the inner key top 2K ′ is thin, and the arm 2K ″ is formed in a shape that is bent in a mound shape so as to surround the key top 2K ′ to obtain a relatively long effective length. It is possible to perform key input with pressing force and a short stroke.

Further, since the reinforcing plate 7 having high rigidity and excellent in flatness is adhered to the lower surface of the printed circuit board 6, even if the circuit board 6 is made of a material that is easily warped or twisted, the flatness is ensured. Therefore, excellent operability can be realized without causing variations in key strokes and operating loads.

Although the calculator has been described as an example in the above, the present invention can be applied to a device such as an electronic translator.

[Effect] As is clear from the above description, according to the present invention, a flexible film-like mounting sheet having a key symbol formed on a keyboard portion, and an electronic element provided in contact with the mounting sheet, are provided. A first reinforcing plate made of a conductive elastic member for protecting the device, a second reinforcing plate having conductivity and provided to cover the lower surface of the device and maintain the strength of the entire device, and the first reinforcement. Printing with an elastic tongue formed on a plate and having a tip bent in the direction of the second reinforcing plate and arranged between the first reinforcing plate and the second reinforcing plate to form a circuit pattern A circuit board, and a tongue piece provided on a part of the printed circuit board at a position corresponding to the elastic tongue and having a circuit pattern connected to the ground potential of the printed circuit board on the upper and lower surfaces thereof, The tongue portion of the first reinforcing plate is the printed By pressing the upper surface of the tongue piece of the road board and bringing the lower surface of the tongue piece into contact with the second reinforcing plate, the first reinforcing plate and the second reinforcing plate are simultaneously grounded to the ground potential of the printed circuit board. The printed circuit board is effectively reinforced by the first and second reinforcing plates, and the first reinforcing plate prevents electrostatic discharge from the operating surface from being transmitted to the circuit element. , To ground potential, and by electrostatically shielding by the second reinforcing plate, it is possible to effectively prevent accidents such as destruction of circuit elements and data destruction, and the elastic tongue provided on the reinforcing plate. The first and second reinforcing plates and the printed circuit board to the same potential through the tongue of the printed circuit board,
It is possible to provide an excellent electronic device that enables easy and reliable electrical connection.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a calculator adopting the present invention, FIG. 2 is an external perspective view of a calculator according to the present invention, and FIG. 3 is a perspective view showing the structure of the frame of FIG. Fig. 4 is a perspective view showing the structure of the reinforcing plate of Fig. 3, Fig. 5 is a sectional view taken along line XX of Fig. 2, and Fig. 6 is a sectional view taken along line YY of Fig. 2. Figure, Figure 7 is the second
It is sectional drawing of the ZZ line of a figure. 1 ... Cover sheet, 2 ... Frame 3,7 ... Reinforcement plate, 4 ... Contact sheet 5 ... Insulating spacer, 6 ... Printed circuit board 9 ... Solar cell, 10 ... Display

Claims (1)

[Claims] 1. A flexible film-like mounting sheet having a key symbol formed on a keyboard portion, and a conductive elastic member provided in contact with the mounting sheet for protecting electronic elements. A reinforcing plate, a second reinforcing plate which covers the lower surface of the device and is provided to maintain the strength of the entire device, and which has conductivity, and which is formed on the first reinforcing plate and extends in the direction of the second reinforcing plate. An elastic tongue having a bent tip; a printed circuit board having a circuit pattern formed between the first reinforcing plate and the second reinforcing plate; and a position corresponding to the elastic tongue. And a tongue piece provided on a part of the printed circuit board and having a circuit pattern connected to the ground potential of the printed circuit board on the upper and lower surfaces thereof, wherein the tongue portion of the first reinforcing plate is the printed circuit board. While pressing the tongue upper surface of By contacting the strip lower surface to the second reinforcing plate, wherein the first reinforcing plate and the second
The reinforcing plate of (1) is connected to the ground potential of the printed circuit board at the same time.