JPS6214253A - Electronic equipment - Google Patents

Abstract

PURPOSE:To enhance the rigidity of the device and to make secure the shield effect by pressing the ground electric potential pattern of the circuit board at a part of the first reinforced plate which is conductive and is connected to the operating surface and contacting to the second reinforced plate at the lower surface of the device. CONSTITUTION:At the lower part of a covering sheet 1 of the device, a reinforcing plate 3 made of the metallic thin plate is inserted and molded at a frame 2 formed by the insulating plastics. Since a tongue part 3F' of an L-shaped flange 3F formed at the outer circumference of the reinforcing plate 3 displaces downward a tongue piece 6b of a printed circuit board 6 by the elastic force and contacts it with a reinforcing plate 7 made of the thick metallic plate, the high rigidity and the shield effect can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic device, and particularly to an electronic device in which the rigidity of the device is ensured by a laminated structure of constituent members with a reinforcing plate interposed therebetween.

[Prior Art] Devices such as electronic calculators (hereinafter referred to as calculators) and electronic translators have been reduced in size and weight, and card-type devices have become commonplace in recent years.

[Problems to be Solved by the Invention] Due to its portability, devices that have been reduced in size and weight are taken out into all kinds of environments and used under a wide range of conditions. Therefore, not only environmental resistance with respect to temperature and humidity, but also measures against electrostatic discharge are required.

For example, circuit elements such as MOS semiconductors used for power saving are susceptible to static electricity, and static electricity accumulated on the human body or clothing during operation can be discharged through the keyboard and destroyed, or in the case of memory etc. This causes problems such as changes in saved data. Therefore, metal members within the device that tend to attract static electricity must be connected to the ground potential of the circuit.

This type of grounding member can be easily installed in miniaturized equipment, without increasing the size of the entire equipment, and can ensure stable connections against bending, twisting, and impact applied to the equipment. Must also be.

Means for Solving Problem E] In order to solve the following problems, the present invention includes a conductive Ml reinforcing plate provided in contact with the device operation surface, and a conductive plate covering the bottom surface of the device. A configuration was adopted in which a portion of the first reinforcing plate presses the circuit pattern connected to the ground potential of the circuit board inside the device and brings it into contact with the second reinforcing plate.

[Function] A metal reinforcing plate 3 is inserted into the frame 2 shown in Fig. 1, and the tongue portion 3F provided on the flange of this reinforcing plate 3
' is a tongue piece 6b having a grounding pattern of the circuit board 6, which is pressed downward during stacking to bring it into contact with the metal reinforcing plate 7. As a result, static electricity from the operation surface of the covering sheet 1 is guided to the ground potential without affecting the circuit elements. Also,
Since the reinforcing plate 7 functions as an electrostatic shielding plate, accidents such as destruction of elements and data loss due to static electricity can be prevented.

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

FIG. 1 is an exploded perspective view showing the structure of a linear calculator as an example of an electronic device according to the present invention. By laminating each member of the calculator, a card-shaped electronic calculator having an appearance as shown in FIG. 2 is obtained.

First, to explain the exterior, as shown in FIG. 2, a keyboard K consisting of a plurality of numerical keys and operation keys is formed on the surface of this calculator. In front of the keyboard, a display section consisting of an LCD for displaying input data and calculation results without displaying them on the r+i view, and a solar cell section B for supplying power to the ρ1 path in the device are arranged.

The surface of the device shown in Fig. 2 is made of a covering sheet l shown by the symbol l in Fig. 1. The covering sheet l is a flexible film such as polyester, polycarbonate, polyvinyl chloride, or urethane that has good light transmission. The key symbol IK for the keyboard is printed on the material. The portions corresponding to the display portion and the solar cell portion B are not printed, and are transparent portions ID and IB that take advantage of the transparency of the material.

A frame 2 made of integrally molded insulating plastic is arranged at the bottom of the facing sheet 1. As shown in FIG. 3, a reinforcing plate 3 made of a thin metal plate is insert-molded into the frame 2. Key manual parts 2K are formed at positions corresponding to the key symbols IK of the mounting sheet 1, respectively.

An inner key top 2K" is located in the center of the circular hole in the key power section 2, and its top surface is approximately at the same height as the top surface of the frame 2.
is integrally formed with the main body by a plurality of thin arms 2. Therefore, when the key symbol IK part of the cover sheet 1 attached to the upper surface of the frame 2 is pressed, the film of the cover sheet l is bent downward. , the upper surface of ' is pressed by the inner key top 2, and the arm 2 is elastically deformed, causing it to be displaced downward approximately in parallel.

The displacement amount of 1' on the inner key top 2 can be adjusted to the desired value for the operation stroke and operation load by adjusting the length and thickness 1 width of the arm 2. However, when molding the frame 2, Since the molding material flows into the inner key top 2 through the arm 2 section, it is necessary to set the arm 2 dimension to prevent short molding. is made thin to achieve a short operating stroke and small operating load.

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

On the other hand, the reinforcing plate 3 to be inserted is formed into an outer shape by etching, pressing, or other methods from a rigid and highly elastic metal such as stainless steel, phosphor bronze, or brass. The external shape before the insert is as shown in Figure 4. An L-shaped flange 3F facing toward the bottom surface of the calculator is formed on the outer periphery of the reinforcing plate 3. This flange portion is buried in the resin of the frame 2 when inserted, improving the rigidity of the entire frame and increasing resistance against twisting and bending. square hole 3
D, 3B is the display device 10.D arranged below. solar cell 9
This serves as a window for viewing the outside of the device. Further, a tongue portion 3F' is formed by cutting out the flange 3F and applying bending T to the outer periphery near the square hole 3B. This tongue part 3F
' is for lowering frame 2 to the ground potential of the circuit,
It is exposed through a square hole 2H provided at a corresponding position.

Note that the frame 2 to the reinforcing plate 3 shown in FIG. 3 are flush with each other at their L surfaces, and the reinforcing plate 3 is in direct contact with the back surface of the facing sheet l during lamination.

On the F side of the frame 2, a flexible contact sheet 4 having a printed pattern formed on its lower surface to serve as movable key contacts is arranged. The contact sheet 4 is made by printing a contact pattern 4a on a thin film such as a polyester film using conductive ink such as carbon paste at a position corresponding to the key manual portion of the frame 2.

This contact pattern 4a is pushed by the inner key top 2 of the frame 2 at 1, is displaced in the 0 direction, and is connected to the fixed contact 6a on the upper surface of the printed circuit board 6, which is disposed opposite to the inner key top 2 of the frame 2 through the round hole 5a of the insulating spacer 5. Contact. Keying is performed by short-circuiting the fixed contact ρ due to contact between the contacts.

An LSI 8 forming an arithmetic circuit is mounted on the printed circuit board 6, and key human input signals are guided to the LSI 8. L
The SI 8 performs calculations according to the input, and outputs the results or intermediate results to the display 10. The drive signal for the 0 display 10 for visible display is sent to J via the heat seal connector 11.
I can get it. Since the LSI 8 and the display lO are operated by a weak current supplied from the solar cell 9 through the heat seal connector 11, the LSI 8 is a C-MOS type, and the display 10 is an LCD (liquid crystal display). Aim to reduce power consumption.

Further, a tongue piece 6b formed by cutting out a U-shaped sleeve 2 on the board is formed at a position corresponding to the tongue part 3H of the frame 2 of the printed circuit board 6, and the tongue part 3H and the contact point are formed. The sheet 4 and the insulating spacer 5 face each other via 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.

A relatively thick metal reinforcing plate 7 is adhered and fixed to the frame 2 from the bottom surface of the printed circuit board 6 using an adhesive 7a, thereby forming a contact sheet 4. Insulating spacer 5. By sandwiching the printed circuit board 6, the laminated structure of the device is completed. At this time,
The tongue portion 3F' of the frame 2 presses down the tongue piece 6b of the circuit board 6 and comes into contact with the portion 7b to which adhesive is not applied of the reinforcing plate 7 at the lowest layer, thereby causing the reinforcing plate 7 and the reinforcing plate 3 of the frame 2 to is connected to the circuit ground potential.

FIG. 5 is a cross-sectional view taken along line XX in FIG. 2, viewed in the direction of the arrow. As shown in FIG. The tongue piece 6b of the circuit board 6 is displaced downward and brought into contact with the reinforcing plate 7.

With such a structure, the reinforcing plate 3 is lowered to the ground potential of the circuit, so that static electricity transmitted from the surface of the facing sheet during operation can be released to the metal reinforcing plate 3 and further to the circuit to the ground potential, and the solar cells 9, Display device lO1 or LSI
8 can be prevented from being applied to the circuit network containing the 8. Further, since the reinforcing plate 7 is installed in the same manner, an electrostatic shielding effect can be obtained, and a higher protection effect can be realized.

In addition, as shown in FIG.
Since the solar cell 9 is constructed so as to surround the calculator, it is difficult to deform even when stress such as twisting or bending is applied to the entire calculator, and the solar cell 9 made of a easily damaged material such as a silicon wafer or a glass plate can be protected.

Similarly, as shown in FIG. 6 (a cross-sectional view taken along the line Y-Y in FIG. 2 in the direction of the arrow), the display 10 is also surrounded by a reinforcing plate 3.7, so that the display 10 is not exposed to force. This structure, which requires no force, is effective when using easily damaged displays such as LCDs that hold liquid crystals using glass plates.

Fig. 7 shows a cross section along the Z-Z line in Fig. 2, viewed in the direction of the arrow. , the contact sheet 4 is brought into contact with the printed circuit board 6, and the contact pattern 4b is connected to the fixed contact 6a.
, 6a is performed. As mentioned above, the arm 2 that holds ' on the inner key top 2
The key top 2 is bent into a snake-like shape to surround the key top 2 and has a relatively long effective length, so that the keys can be pressed manually with a small pressing force and a short stroke. can.

Furthermore, since a reinforcing plate 7 with high rigidity and excellent flatness is adhered to the lower surface of the printed circuit board 6, flatness is ensured even if the circuit board 6 is made of a material that is prone to warping or twisting. As a result, excellent operability can be achieved without variations in keystrokes or operating loads.

Although the calculator has been described as an example in 1- below, the present invention can also be applied to devices such as electronic translators.

[Effects] As is clear from the above description, according to the present invention, a first conductive reinforcing plate provided in contact with the device operation surface and a second conductive reinforcing plate covering the bottom surface of the device are provided. , the circuit pattern connected to the ground potential of the circuit board inside the device is pressed by a part of the first reinforcing plate and brought into contact with the second reinforcing plate, so that static electricity discharge from the operation surface is avoided. The circuit element f-
Niri.

To provide an excellent electronic device that can effectively prevent accidents such as destruction of circuit elements and data destruction by guiding the electrostatic potential to the ground potential without causing any damage, and by providing electrostatic shielding with a second reinforcing plate. can.

[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 an electric calculator according to the present invention, and Fig. 3 shows the structure of the frame shown in Fig. 1. FIG. 4 is a perspective view showing the structure of the reinforcing plate in FIG. 3, FIG. 5 is a sectional view taken along line XX in FIG. 2, and FIG. Cross-sectional view, Figure 7 is the second
It is a sectional view taken along the Z-Z line in the figure.

Claims (1)

[Claims] a first electrically conductive reinforcing plate provided in contact with the device operation surface;
A second conductive reinforcing plate is provided to cover the bottom surface of the device, and a part of the first reinforcing plate presses the circuit pattern connected to the ground potential of the circuit board inside the device to contact the second reinforcing plate. An electronic device characterized by: