JPH0212661Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial field of application> The present invention relates to a key unit used in the operating section of household electronic equipment such as a microwave oven, and particularly to a key unit made of a flexible film, which is generally called a membrane key. It is something.

<Prior Art> First, the structure of a conventional key unit will be explained based on FIG. FIG. 1a is an external perspective view of the key unit, and FIG. 1b is an exploded perspective view of the key unit.

In the figure, 1 is a character sheet on which letters, numbers, etc. are printed, and is generally made of a flexible film such as a polyester film called PET. This character sheet 1 may be provided with an aluminum vapor-deposited film on its inner surface in order to improve the print quality and eliminate problems caused by static electricity. 2 is an upper pattern sheet on which a wiring pattern with key contacts is formed on the inner surface using a conductive material such as silver, carbon, or aluminum;
It is made of flexible film such as PET. 3
4 is an insulating spacer made of an insulating sheet with an opening provided at a position corresponding to the keypad of the character sheet 1;
Similar to the upper pattern sheet 2, the lower pattern sheet has a wiring pattern formed with a conductive material and having key contacts on its inner surface. The wiring pattern on the upper pattern sheet 2 and the wiring pattern on the lower pattern sheet 4 mutually constitute a matrix, and each has a different combination of wiring patterns for different keypads. 5 is a reinforcing plate that prevents the key unit from being deformed when the keypad portion is pressed. The key unit is constructed by adhering the character sheets 1 to the reinforcing plate 5 to each other with adhesive material such as double-sided tape.

FIG. 2 is a perspective view showing the lead portion used in the key unit, in which lead portions 6 and 7 are led out from the upper pattern sheet 2 and the lower pattern sheet 4, respectively, in order to extract signals from the key unit to the outside. . The wiring patterns of the lead parts 6 and 7 are arranged on opposite sides so as not to face each other, but in consideration of the arrangement of terminals of a connector connected to the outside, they are arranged as evenly spaced as possible.

The lead portion 6 of the pattern sheet 2 is cut off near the end on the side where no wiring pattern is arranged, so that the wiring pattern 9 on the lead portion 7 of the lower pattern sheet 4 is exposed. Similarly, the lead portion 7 of the lower pattern sheet 4 is cut off near the end on the side where the wiring pattern is not arranged, so that the wiring pattern 8 on the lead portion 6 of the upper pattern sheet 2 is exposed. Reference numeral 10 denotes a fixing band that fixes the lead parts 6 and 7 so that they do not come apart.

The key unit configured as described above has ventilation holes 11, 1 for removing air during adhesion by the adhesive material or gas generated during drying, as well as venting gas from the opening space of the insulating sheet 3 when the keypad is pressed.
1, 11, and 11 are provided on the lower pattern sheet 4 and the reinforcing plate 5 in a number corresponding to the number of key pads.

FIG. 3 is an exploded perspective view of the main parts of the key unit in which the number of ventilation holes 11 is reduced to one, 12 is an upper pattern sheet, 13 is four openings 13', and 4 openings 13' are communicated diagonally through elongated grooves 15. Insulating sheet made of 14
This is a lower pattern sheet having a wiring pattern 14' having a key contact made of a conductive material on its upper surface, and a ventilation hole 16 provided at a position corresponding to the diagonal intersection of the grooves 15.

<Problems to be solved by the invention> In the case of a configuration in which ventilation holes are provided in the lower pattern sheet and the reinforcing plate, the positions of the ventilation holes are fixed, so key units with the same external shape but different key positions are punched out. It was difficult to standardize processing dies.

That is, in order to provide ventilation holes in the lower pattern sheet and the reinforcing plate, it is necessary to perform punching using a mold, but when manufacturing key units with different designs that have the same external shape but different key arrangements,
The ventilation hole must be formed at a location different from the key unit due to the key arrangement. Therefore, in order to provide ventilation holes at different positions, separate molds had to be prepared for each key unit with a different key arrangement.

There is a problem in that manufacturing a separate mold for each key unit having a different key arrangement increases the cost of the mold accordingly, which causes an increase in the manufacturing cost of the key unit.

Regarding the reinforcing plate, it is not possible to standardize the reinforcing plate because it is necessary to manufacture a key unit with ventilation holes in different positions for each key unit with a different design with a different key arrangement, and therefore it is impossible to reduce the cost of the reinforcing plate. There was a problem.

<Means for solving the problem> An insulating spacer having an opening corresponding to the key contact portion is disposed between an upper pattern sheet and a lower pattern sheet on which a wiring pattern having key contacts is formed on the inner surface, A communication path connecting the opening and the lateral outside of the key unit is formed in the insulating spacer by cutting out the insulating spacer.

<Operation> Gas in the opening space escapes to the outside of the key unit through the communication path. Therefore, ventilation holes in the lower pattern sheet and reinforcing plate are unnecessary.

<Example> Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 4 is an exploded perspective view of the main parts of a key unit showing an embodiment of the present invention. The upper pattern sheet 12 and the lower pattern sheet 14, which are the same parts and equivalent parts as in the conventional example, are given the same symbols as in the conventional example. ,
The explanation will be omitted.

17 in the figure are four openings 1 connected by elongated grooves.
This is an insulating spacer made of an insulating sheet in which a communication path 18 communicating between the 7' space and the outside of the key unit is formed by an elongated notch.

The communication passage 18 serves to remove air during adhesion by the adhesive material or gas generated during drying, and also serves to release gas from the space in the opening 17' to the outside of the key unit when the keypad is pressed.

Therefore, as in the conventional example, the lower pattern sheet 14
Since there is no need to provide ventilation holes in the reinforcing plate (not shown), when producing key units with the same external shape and design, the die for punching the lower pattern sheet and the die for punching the reinforcing plate can be used as they are. This eliminates the need for new mold costs and reduces the production cost of key units.

Note that even if the insulating spacer is formed by printing an insulating resist on the upper pattern sheet 12 or the lower pattern sheet 14 instead of the insulating sheet 17,
Of course, similar effects can be obtained.

<Effects> According to the present invention, the ventilation holes in the lower pattern sheet and the reinforcing plate can be eliminated, so that the punching mold can be used in common for key units of different designs that have the same external shape but different key arrangements. Furthermore, since there is no need to manufacture separate molds for each key unit with a different key arrangement, mold costs do not increase, and the cost of the key unit can therefore be reduced.

Furthermore, since the reinforcing plate does not have ventilation holes, it can be used as is for key units of different designs with the same external shape and different key layouts, which has the excellent effect of standardizing the reinforcing plate and reducing costs accordingly.

[Brief explanation of drawings]

Fig. 1a is an external perspective view of a key unit, Fig. 1b is an exploded perspective view showing an example of a conventional key unit, Fig. 2 is an enlarged perspective view of the lead portion of the key unit, and Fig. 3 is another example of a conventional key unit. FIG. 4 is an exploded perspective view of essential parts showing an example of the key unit of the present invention. 12... Upper pattern sheet, 14... Lower pattern sheet, 14'... Wiring pattern, 17...
...Insulating spacer, 18...Communication path.

Claims (1)

[Claims for Utility Model Registration] An insulating spacer having an opening corresponding to the key contact portion is disposed between an upper pattern sheet and a lower pattern sheet on which a wiring pattern having key contacts is formed on the inner surface, and A key unit in which an opening space can be communicated with the outside, characterized in that a communication path connecting the opening and a lateral outside of the key unit is formed in the insulating spacer by cutting out the insulating spacer.