JPH10302572A - Keyboard switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a keyboard switch in which the number of components is few so as to be thin type and be miniaturized, and contact stability and click feeling are superior. SOLUTION: A keyboard switch is composed of a cover main body portion 1 into which a key top 1a, an upper cover 1b, and a positioning boss 1c integrated by molding, a metal dome 2 which is a moving contact, a fixed contact 4 which is formed on a thin type printed board 5, a cover film 3 which covers the metal dome 2 and its periphery, an air hole 8 which is bored in the printed board, and the like. When the key top 1a is pushed down, the metal dome 2 is pushed down so as to touch the fixed contact 4 to switch on. Then, compressed air in the dome 2 escapes outward from the air hole 8 so as to obtain proper finger pressure and click feeling. The static electricity, and invation of dust, dirt, and the like into the metal dome 2 is prevented by the cover film 3 so as to enhance the stability of the contact.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a keyboard switch, and more particularly to a keyboard switch used for a small electronic device such as a mobile communication body.

[0002]

2. Description of the Related Art In recent years, electronic components used in electronic devices such as mobile communication devices have been reduced in size and thickness, and accordingly, keyboard switches capable of effectively utilizing space have been frequently used. It has become.

Conventionally, an example of this type of keyboard switch is disclosed in Japanese Utility Model Laid-Open No. 2-119325. FIG. 2 is a side sectional view showing this conventional example. FIG.
5, a fixed contact 25 is formed on a printed circuit board 21, and an elastic member 24 is interposed between a metal dome 22 disposed immediately above the printed circuit board 21 and a key top 23 thereon. When the key top 23 is pressed from above the top sheet 27 with a finger, the metal dome 22 is pushed down and contacts the fixed contact 5 to form a switch circuit. The spacer 26 is dimensioned to give a sufficient operation stroke to the key top.
The upper sheet 27 fixes the key tops and the spacers at predetermined positions over the entire upper surface.

[0004]

As described above, the conventional keyboard switch is assembled from components such as a top sheet, a key top, an elastic material, and a spacer. However, since the number of components is large, cost reduction or miniaturization can be achieved. There is a problem that the thickness cannot be sufficiently reduced. Although the click feeling is improved by using components such as an elastic material and a spacer, there is a problem that the click feeling is not sufficient.

[0005]

A keyboard switch according to the present invention is arranged such that a printed circuit board having switch contacts formed by a pattern, a metal dome disposed on the printed circuit board, and a center of the metal dome are pressed down. One or two switches comprising a key top, an upper cover for fixing a positional relationship among the key top, the metal dome, and the printed circuit board, and a plurality of spacers for fixing the upper cover and the printed circuit board. In the keyboard switch arranged as described above, each metal dome is provided with an air hole for releasing air in the metal dome to the outside when the key top is pressed on the printed circuit board.

Alternatively, in the keyboard switch, a cover film covering an outer surface of the metal dome is provided so as to seal the inside of the metal dome.

Further, the upper cover, the spacer, and the key top may be integrated with a molded member.

Further, a flexible substrate made of polyester or polyimide and a reinforcing plate for reinforcing the flexible substrate may be used as the printed circuit board.

Further, a rigid board may be used as the printed board.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1A is a side sectional view showing the structure of the embodiment.

In FIG. 1A, a printed circuit board 5 includes
The fixed contact 4 is formed on a flexible printed circuit board 5 made of a flexible substrate such as polyester or polyimide which can be made thin. In addition, a reinforcing plate 6 is provided at the lower part of the printed board 5 as a firm support.
Is pasted. Fixed contact 4 on printed circuit board 5
Is formed, and the metal dome 2 disposed directly above the metal dome 2 is fixed by a cover film 3 made of polyester or the like so as to cover the entire surface of the metal dome 2 and the peripheral printed circuit board 5 so as not to shift. As a result, malfunction of the device is prevented without generating static electricity in the metal dome portion 2 and dust such as dust is prevented from entering the metal dome 2 to prevent poor contact of the switch contacts.

The key top 1a, the upper cover 1b, and the positioning boss 1c arranged on the metal dome 2 form a molded cover body 1 in an integrated structure, and the positioning boss 1c is connected to the printed circuit board 5 and the reinforcing plate 6. Inserted into the positioning holes and fixed.

When the key top 1a of the cover main body 1 is pressed, the metal dome 2 is pushed down, and the air in the metal dome 2 is pushed downward from the air holes 8 of the printed circuit board 5 and the reinforcing plate 6, and the metal dome 2 The fixed contact 4 contacts to form a switch circuit. By providing the air hole 8, when the key top 1b is pressed to operate the switch,
The air pressure inside the metal dome 2 can be reduced, and the finger pressure can be kept moderate to obtain a good click feeling.

Each metal dome 2 is crushed by finger pressure when the switch is operated, but returns to its original shape and position when the finger pressure is removed. Although the cover body 1 is made of a mold, the thickness of the upper cover 1b is so small that the key top 1a can be pushed down by finger pressure.

FIG. 1B is a side sectional view of another embodiment. The difference from FIG. 1A lies in the printed circuit board.
This is an example in which a rigid board having a strength that can be made thin without requiring a reinforcing plate is used for the printed board 7.

[0016]

As described above, in the keyboard switch of the present invention, the key top, the upper cover, etc. are formed in an integrated structure, and the printed circuit board is made thin, so that it contributes to cost reduction, thinness, and miniaturization. This has the effect. In addition, air holes are provided on the printed circuit board to optimize finger pressure and improve click feeling. Furthermore, since the metal dome is covered with a cover film, malfunction of the device due to static electricity is prevented, and contact of contacts is prevented by preventing dust and dirt from entering. There is an effect that conversion can be obtained.

[Brief description of the drawings]

FIGS. 1A and 1B are side sectional views showing an embodiment of the present invention, wherein FIG. 1A shows a first embodiment and FIG. 1B shows a second embodiment.

FIG. 2 is a side sectional view showing the structure of a conventional keyboard switch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cover main body part 2 Metal dome 3 Cover film 4 Fixed contact 5, 7 Printed circuit board 6 Reinforcement plate 8 Air hole 1a Key top 1b Upper cover 1c Positioning boss

Claims (5)

[Claims] 1. A printed circuit board having a switch contact formed by a pattern, a metal dome disposed on the printed circuit board, a key top arranged to press down the center of the metal dome, the key top, and the metal dome. A keyboard switch in which one or two or more switches including an upper cover for fixing a positional relationship between the upper cover and the printed circuit board and a plurality of spacers for fixing the printed circuit board are arranged. A keyboard switch comprising an air hole for releasing the air in the metal dome to the outside when the key top is pressed, for each metal dome. 2. A printed circuit board having a switch contact formed by a pattern, a metal dome disposed on the printed circuit board, a key top arranged to press down the center of the metal dome, the key top and the metal dome. A keyboard switch in which one or two or more switches including an upper cover for fixing a positional relationship with the printed board and a plurality of spacers for fixing the upper cover and the printed board are arranged. A keyboard switch, comprising: a cover film covering an outer surface of the metal dome so as to hermetically seal the dome. 3. The keyboard switch according to claim 1, wherein the keyboard switch has a structure in which the upper cover, the spacer, and the key top are integrated with a mold member. 4. The printed circuit board according to claim 1, wherein a flexible substrate made of polyester or polyimide and a reinforcing plate for reinforcing the flexible substrate are used.
Keyboard switch as described. 5. The keyboard switch according to claim 1, wherein a rigid board is used as said printed board.