JP2001143568A - Key switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a key switch that can accomplish a sure switch operation and compactness without loss of clicking sensation when pressing a key top. SOLUTION: A key switch 1 has a print substrate 2 having a fixed electrode 10 in the form of comb constituted by parallel-arranging a signal electrode 10a with a ground electrode 10b in turn, a switch 4 in the form of sheet constituted by forming a movable electrode 4a into a flexible insulating sheet 4A, and a metallic click dome 5 held using a flexible seal 9 in position corresponding to the movable electrode 4a, wherein the key switch reverse-operates the click dome 5 by pressing the key top 7 and engages the movable electrode 4a of the switch in the form of sheet with the fixed electrode 10 in the form of comb of the printed board 2, the pressing spacer 4b is arranged to the position corresponding to the movable electrode 4a located in an opposed surface with surface into which the movable electrode 4a of the flexible insulating sheet 4A is formed to press the movable electrode 4a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a key switch used in a portable telephone or the like, and more particularly, to a key switch formed by combining a sheet-like switch and a metal click dome.

[0002]

2. Description of the Related Art FIGS. 8 and 9 show a conventional key switch used in a portable telephone or the like. The key switch A includes a printed board B, a sheet-like switch S, a click dome D, a holding member H, and It is composed of a key top K.

On the printed board B, a comb-shaped fixed electrode E formed by alternately juxtaposing signal electrodes Ea and ground electrodes Eb is formed on the upper surface thereof. On the other hand, the sheet-like switch S
Is formed by forming a movable electrode Sb on a flexible insulating sheet Sa, and is provided on the upper surface of the printed circuit board B in such a manner that the movable electrode Sb faces the comb-shaped fixed electrode E.

A click dome D made of metal is provided above the flexible insulating sheet Sa of the sheet-like switch S at a position corresponding to the movable electrode Sb with the flexible insulating sheet Sa interposed therebetween. It is held by a seal F.

Further, a holding member H is provided above the sheet-like switch S and the click dome D, and a key top K is provided above the holding member H at a position facing the click dome D. I have. The symbol C in the figure indicates a casing (casing) of a mobile phone or the like.

In the key switch A having the above configuration, FIG.
When the key top K is pressed from the normal state shown in FIG.
When the click dome D is inverted and the click dome D is inverted, a click feeling is obtained, and as shown in FIG. 9, the click dome D is inverted and the sheet-like switch S is pressed down, and the movable electrode Sb is comb-shaped. The switch is made by contacting the fixed electrode E and shorting the signal electrode Ea and the ground electrode Eb.

[0007]

The metallic click dome D employed in the above-mentioned conventional key switch A has a shape in which the entire surface including the top is cut out from a part of a spherical surface. Therefore, when the key top K is pressed to perform the reversing operation, the stroke hanging down from the mounting surface is large and close to the stroke limit of the click dome D itself. Therefore, the movable electrode Sa of the sheet-like switch S is
The point is pressed at the top of the inverted spherical surface of the click dome D.

For this reason, in the conventional key switch A, a short circuit between the signal electrode Ea and the ground electrode Eb due to the movable electrode Sa becomes uncertain, and there is a disadvantage that the switch operation becomes unstable such as chattering.

On the other hand, as a solution to the problem caused by the use of the metal click dome as described above, the movable electrode of the sheet-like switch is formed in a dome shape together with a flexible sheet, so that the signal electrode and the ground electrode of the comb-like fixed electrode are formed. There is a key switch that is configured to surely short-circuit the switch.

[0010] However, in order to obtain a click feeling at the time of depressing the key top by using the dome formed on the flexible sheet of the sheet-like switch, a long key stroke is required. There is a problem that it is more difficult to make the device compact than a switch.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a key switch capable of achieving a reliable switch operation and compactness without impairing a click feeling when a key top is pressed. It is.

[0012]

In order to achieve the above object, a key switch according to the present invention comprises: a printed circuit board having a comb-shaped fixed electrode in which signal electrodes and ground electrodes are alternately arranged; Switch formed by forming a movable electrode facing a comb-shaped fixed electrode on a flexible insulating sheet, and a position corresponding to the movable electrode with the flexible insulating sheet interposed therebetween in the flexible insulating sheet of the switch. A metal click dome held by using a flexible seal, and a key top arranged opposite to the click dome via a holding member, and the click dome is turned over by pressing the key top to form a sheet. The movable electrode of the switch
A key switch for making a switch by making contact with a comb-shaped fixed electrode of a printed circuit board and short-circuiting a signal electrode and an earth electrode, wherein a movable electrode of a flexible insulating sheet in a sheet-like switch is formed. A pressing spacer for pressing the movable electrode is provided at a position corresponding to the movable electrode on the surface opposite to the surface on which the movable electrode is provided.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing embodiments. 1 to 7 show an example in which the key switch according to the present invention is applied to a key switch of a mobile phone.

As shown in FIGS. 1 and 2, the key switch 1 according to the present invention comprises a printed circuit board 2 and a switch unit 3, and the switch unit 3 includes a sheet-like switch 4, a click dome 5, , Holding member 6 and key top 7. Note that the printed circuit board 2 and the switch unit 3 are housed and installed in a casing (casing) 8 of the mobile phone.

As shown in FIGS. 1 to 3, a wiring pattern 2 p including a comb-shaped fixed electrode 10 is provided on the upper surface of the printed circuit board 2.
Are formed, and various electronic circuit components (not shown) are mounted.

As shown in FIG. 3, the comb-shaped fixed electrode 10 has a signal side pattern 10 having a plurality of signal electrodes 10a.
A and an earth-side pattern 10B having a plurality of earth electrodes 10b. The signal electrodes 10a and the earth-side electrodes 10b are alternately arranged at predetermined intervals.

Incidentally, in the comb-shaped fixed electrode 10 of the embodiment, the width of each of the signal electrode 10a and the ground electrode 10b is set to 0.2 mm, and the distance between the signal electrode 10a and the ground electrode 10b is set to 0.2 mm. The circuit pattern 2p (FIGS. 1 and 2) surrounding the comb-shaped fixed electrode 10 is covered with a resist film 2R.

On the other hand, the sheet-like switch 4 corresponds to FIGS.
As shown in FIG. 4, a movable electrode 4a made of a conductive metal thin film and a gap material 4g surrounding the movable electrode 4a are formed on the lower surface of the flexible insulating sheet 4A. It is provided on the upper surface of the printed circuit board 2 so as to face the fixed electrode 10.

The movable electrode 4a is connected to all the signal electrodes 10a of the comb-shaped fixed electrode 10 and the ground electrode 1
0b. Also,
In the state provided on the upper surface of the printed circuit board 2,
The movable electrode 4a is separated from the comb-shaped fixed electrode 10 via the gap material 4g.

As shown in FIGS. 1 and 2, on the upper part of the flexible insulating sheet 4A in the sheet-like switch 4,
At a position corresponding to the movable electrode 4a with the flexible insulating sheet 4A interposed therebetween, a pressing spacer 4b for pressing the movable electrode 4a is formed by printing so as to have substantially the same diameter as the movable electrode 4a. At the same time, the click dome 5 made of metal is held by using a flexible seal 9. As shown in FIG. 5, the click dome 5 is held on the flexible insulating sheet 4A so that the centers of the click domes 5 and the comb-shaped fixed electrodes 10 of the printed circuit board 2 coincide with each other.

The diameter of the click dome 5 is set to be substantially the same as the outer diameter of the comb-shaped fixed electrode 10 (signal side pattern 10A and ground side pattern 10B), and the outer periphery of the click dome 5 is comb-shaped fixed electrode. 10 is located above the periphery.

As shown in FIGS. 1 and 2, above the sheet-like switch 4 and the click dome 5, a base portion 6 is provided.
A is provided with a holding member 6 formed with a moving portion 6C via a flexible portion 6B, and a keytop 7 is provided above the moving portion 6C in a manner positioned above the click dome 5.

In the key switch 1 having the above configuration,
When the key top 7 is pressed from the normal state shown in FIG. 1, the flexible portion 6B of the holding member 6 is deformed as shown in FIG.
Descends and is clicked by the moving portion 6C, thereby causing the click dome 5 to move.
Operates in reverse.

At this time, the click dome 5 performs a reversing operation, so that a certain click feeling can be obtained.

When the click dome 5 that has been turned over depresses the sheet-like switch 4, the movable electrode 4 is pressed.
a contacts the comb-shaped fixed electrode 10 and short-circuits the signal electrode 10a and the ground electrode 10b to make the switch.

At this time, the click dome 5 pushes down the sheet-like switch 4 via the push-down spacer 4b.
When the click dome 5 is reversed, the hanging distance from the mounting surface is small, and the click dome 5 is in a state of pressing the pressing spacer 4b, so that the movable contact 4a of the sheet-like switch 4 is fixed to the comb-like fixed electrode. 10, the comb-shaped fixed electrode 1 is pressed in a wider range than the combined width of the pair of signal electrodes 10a and the ground electrode 10b.
The signal electrode 10a and the ground electrode 10b at 0 are reliably short-circuited via the movable contact 4a, so that the make operation of the key switch 1 becomes extremely stable.

In the key switch 1 described above, since the outer periphery of the click dome 5 is located above the periphery of the comb-shaped fixed electrode 10 as described above, the key top 7 is slightly pressed. In the state, the comb-shaped fixed electrode 1 is moved from the normal position shown in FIG.
0 supports the click dome 5 via the sheet-like switch 4, and the gap material 4 g of the sheet-like switch 4
Directly contact the comb-shaped fixed electrode 10.

Thus, the gap between the movable electrode 4a in the sheet-like switch 4 and the comb-like fixed electrode 10 on the printed circuit board 2 is accurate and uniform with reference to the surface of the comb-like fixed electrode 10. The switching operation of the key switch 1 is more reliable and stable.

In the above-described embodiment, an example is shown in which the present invention is applied to a key switch of a portable telephone.
Needless to say, the key switch according to the present invention can be effectively applied to various electronic devices other than the mobile phone.

[0030]

As described above in detail, the key switch according to the present invention comprises a printed circuit board having comb-shaped fixed electrodes in which signal electrodes and ground electrodes are alternately juxtaposed, and a flexible insulating sheet. A sheet-like switch formed with a movable electrode facing the comb-like fixed electrode, and a flexible seal at a position corresponding to the movable electrode across the flexible insulating sheet in the flexible insulating sheet of the sheet-like switch. A metal click dome held by using a key dome, and a key top which is disposed to face the click dome via a holding member, and inverts the click dome by pressing the key top,
A key switch for making a switch by bringing a movable electrode of a sheet-shaped switch into contact with a comb-shaped fixed electrode of a printed circuit board and short-circuiting a signal electrode and a ground electrode, and a flexible insulating sheet in the sheet-shaped switch. A pressing spacer for pressing the movable electrode is provided at a position corresponding to the movable electrode on the surface opposite to the surface on which the movable electrode is formed.

According to the above configuration, since the click dome made of metal is employed, a click feeling can be obtained with a short key stroke when the key top is pressed.

Further, according to the above configuration, when the keytop is pressed, the movable contact of the sheet-like switch is surface-pressed by the pressing spacer provided on the sheet-like switch. The electrode and the movable contact will be reliably short-circuited,
The make operation of the key switch becomes stable.

Thus, according to the key switch of the present invention, it is possible to achieve a reliable switch operation and compactness without impairing the click feeling when the key top is pressed.

[Brief description of the drawings]

FIG. 1 is a sectional side view of a key switch according to the present invention.

FIG. 2 is an exploded sectional side view of the key switch according to the present invention.

FIG. 3 is a plan view of a main part of a printed circuit board in the key switch of the present invention.

FIG. 4 is a bottom view of a main part of a sheet-like switch in the key switch of the present invention.

5A and 5B are a bottom view and a cross-sectional side view of a click dome in the key switch according to the present invention.

FIG. 6 is a cross-sectional side view showing a makeup state of the key switch according to the present invention.

7A and 7B are enlarged cross-sectional views of a main part of a key switch according to the present invention.

FIG. 8 is a sectional side view showing a conventional key switch.

FIG. 9 is a sectional side view showing a makeup state of a conventional key switch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Key switch, 2 ... Printed circuit board, 3 ... Switch unit, 4 ... Sheet switch, 4A ... Flexible insulating sheet, 4a ... Movable electrode, 4b ... Pressing spacer, 5 ... Click dome, 6 ... Holding member, 7 ... key top, 9 ... flexible seal, 10 ... comb-shaped fixed electrode, 10a ... signal electrode, 10b ... ground electrode.

Claims (1)

[Claims] 1. A printed circuit board comprising a comb-shaped fixed electrode in which signal electrodes and ground electrodes are alternately juxtaposed, and a movable electrode opposed to the comb-shaped fixed electrode is formed on a flexible insulating sheet. A sheet-shaped switch, and a metal click dome held using a flexible seal at a position corresponding to the movable electrode with the flexible insulating sheet of the flexible insulating sheet of the sheet-shaped switch interposed therebetween, A key top disposed opposite to the click dome with a holding member interposed therebetween, and the click dome is turned over by pressing the key top, and the movable electrode of the sheet-like switch is
A key switch that makes a switch by making contact with the comb-shaped fixed electrode of the printed circuit board and short-circuiting the signal electrode and the ground electrode, wherein the flexible insulating sheet in the sheet-like switch is A key switch, wherein a pressing spacer for pressing the movable electrode is provided at a position corresponding to the movable electrode on a surface opposite to a surface on which the movable electrode is formed.