JPS61290614A - Keyswitch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a key switch used in a keyboard device or the like, and particularly to a key switch configured to suppress the occurrence of chattering.

<Prior Art> Generally, there is a key switch that has a tactile effect, in which manual key operation of a key switch can be confirmed by touch without the aid of display means.

An example of a key switch having such an effect is a key switch for electronic equipment disclosed in Japanese Patent Application Laid-open No. 117619/1983. According to this key switch, when the key top is pressed down, the protrusion of the key rubber is pressed, and the skirt part gradually deforms under compressive force and the pressing load increases. flexes and rapidly reduces the pressing load. This phenomenon gives a moderate lick feeling to the fingertips, etc., and the lower surface of the pressing part indicated by the conductive rubber presses the upper surface of the flexible printed board, causing conduction between the adjacent patterns for key manual power and transmitting the key human power signal. be done.

If the relationship between the pressing load and the stroke of such a key is illustrated in a diagram, it becomes a load-stroke characteristic curve as shown in FIG. Point G of this curve is the point where the skirt portion of the key rubber buckles, and point H is the point where the lower surface of the suppressing portion comes into contact with the upper surface of the flexible printed board. After passing the H point, the pressing load gives elastic deformation to the key rubber's suppressing action part and protrusion, and the load increases rapidly in a short stroke section, reaching the pressing action limit state, and the switch electrode is pressed and conductive. When this condition is established and the pressing load is removed, the skirt portion returns to its original shape due to its own elastic restoring force, and the switch electrode is opened.

<Problems to be solved by the invention> However, the key switch with such a conventional configuration does not meet the above-mentioned H
At this point, there is a chattering phenomenon in which a movement occurs on the movable part side when the suppressing part and the printed circuit board come into contact, and when the switch electrodes come into contact with each other, and the connection between the switch electrodes repeats a slight disconnection before reaching a stable state. Occur. When this chattering occurs, there is a problem that the input is inputted to the electronic device as an erroneous input, causing the electronic device to malfunction.

Therefore, in order to prevent chattering malfunctions, conventional methods have been used, such as providing electronic equipment with a function to determine whether the switch electrode closure has entered a stable state, or preventing key human input signals from being input for a predetermined period of time. Then, the input signal is called into the electronic device after it becomes stable.

For this reason, there is a problem in that there is a large delay in device operation when the keys are pressed manually, and the keyboard device has a poor operating feel.

<Object of the Invention> The object of the invention is to suppress the occurrence of chattering by pressing the switch electrode in a stable load state even if there is vibration of the fingertip etc. due to chattering when the key is manually operated. This provides a key switch with

Means for Solving the Problems> The present invention was made to solve the above problems, and consists of a key whose key stem is vertically guided and supported by a frame, and a pair of keys that are normally electrically insulated. including electrodes;
A circuit pattern board to which both electrodes are electrically connected when the key is pressed; and an inverted cup that is interposed between the key and the circuit pattern board and normally holds the key in an inoperative position by its own elastic force. Equipped with a shaped rubber spring,
The rubber spring has a base portion that contacts the circuit pattern board, an annular top portion that contacts the lower surface of the key stem of the key, and is located inside the annular top portion and intermediate between the annular top portion and the base portion. a thick disk-shaped operating section; a thin, outwardly bulging side wall section that connects the base section and the annular top; and an outwardly bulging thin side wall section that connects the annular top and the operating section. This is a key switch consisting of an inner wall part.

Function> The present invention is constructed as described above, and when the key is pressed down, the lower surface of the key stem presses against the annular top of the rubber spring.

When the annular top portion is pressed, the side wall portion deforms and the suppressing load increases, and when the annular top portion is further pressed down, the side wall portion buckles and rapidly reduces the suppressing load. This reversing motion provides a tactile effect to the operator, causing the operating portion to come into contact with the circuit pattern board.

When the key is further pressed down, the operating section comes into pressure contact with the circuit pattern board, and as the suppressing load increases, the inner wall section deforms and buckles.

The deformation and buckling of this inner wall absorbs the push stroke, leveling out the load fluctuations of the switch electrode pressure contact, quickly converging the movement of the operating part that occurs when the operating part contacts the circuit pattern board, and making it stable. This is to form the switch electrode in a closed state.

<Example> An example of the present invention will be described below with reference to FIGS. 1 to 4.

1 is a key that is pressed down with a finger, and is made up of a key top 2 that is touched by the fingertip, and a key stem 3 that is fixed to the lower part of the key top 2.

4 is a frame of a keyboard device equipped with a key switch, and is provided with a key guide portion 5 for guiding and supporting the vertical movement of the key stem 3. Then, along the lower part of the frame 4, there is a rubber spring lO1, and a membrane switch 2, which is a circuit pattern board 20, is installed on the lower surface of the rubber spring lO1.
1 and a support plate 30 are arranged, and by fixing the support plate 30 to the frame 4, a rubber spring 10. A membrane switch 21 is held between the frame 4 and the support plate 30.

The frame 4 includes a downwardly extending portion 6 that protrudes downward and supports the upper surface of the base portion 16 of the rubber spring IO with its lower surface.
and rubber spring 10. Membrane switch 21.
A plurality of positioning protrusions 7 for attaching the support plate 30 and protrusions (not shown) for fixing the support plate 30 are provided at predetermined positions, respectively.

The rubber spring 10 is formed of rubber or an elastic polymer material into an inverted cup shape, is housed in the lower space of the key guide portion 5, and is responsible for the key switch action function. This rubber spring lO is
It has an annular apex 11 in the shape of a thread bottom at its upper part, the upper surface of which corresponds to the lower surface of the key stem 3 so as to share its axis, and a side wall 12 that bulges outward is formed on the outer peripheral edge of the lower part. ing. The side wall portion 12 is formed thin, and has an upper portion 12a that is continuous with the annular top portion 11 and has a conical shape.
and a cylindrical lower portion 12b that continues to the lower end of the upper portion 12a, and a bend 12c is formed at the connecting portion between the two. The bent portion 12c is located at the lower center of the side wall portion 12, and is set to be somewhat lower than the lower surface position of the operating portion 14, which will be described later.

Reference numeral 16 denotes a base portion that is continuous with the lower portion 12b of the side M1@12 and supports the entire rubber spring IO between the downwardly extending portion 6 of the frame 4 and the circuit pattern board 20.

An annular groove 15 is provided on the outer peripheral edge of the lower portion 12b, and a positioning hole 17 into which the protrusion 7 can be inserted at a predetermined position.
is provided. Further, a notch lea is provided for adjusting the air pressure inside and outside the space formed by the entire rubber spring IO and the circuit pattern board 20.

Reference numeral 13 denotes an inner wall portion that is continuous with the lower inner circumferential edge of the annular top portion 11 and has a downwardly swollen cross-section that is approximately arcuate, and is formed with a thin wall substantially similar to the side wall portion 12 .

Reference numeral 14 denotes a slightly thick disc-shaped operating part that is continuous with the inner wall part 13 and is provided in the center of the annular top part 11 facing downward. The height is set to approximately the center of the .

20 is a membrane switch 21 and a support plate 3 in the embodiment.
This is a circuit pattern board consisting of 0.

The support plate 30 is a substrate made of a metal material, and is provided with a positioning hole 30a at a predetermined position into which the protrusion 7 can fit, and is further fixed to a protrusion (not shown) of the frame 4.
It forms the base portion of the membrane switch 21cy3.

The membrane switch 21 has an upper pattern film 22
and a lower pattern film 27, and an insulating spacer 25 having an opening 26 forming a predetermined switch operation gap and a positioning hole (not shown) is interposed between the two.

The upper pattern film 22 is made of a flexible plastic film, has a positioning hole (not shown) at a predetermined position, and has a first switch electrode and a predetermined electric circuit pattern 24 formed on the lower surface by printing means. There is.

The lower pattern film 27 is made of the same plastic film as above, has a positioning hole (not shown) at a predetermined position, and has a second switch electrode facing the first switch electrode 23 on the upper surface.
A switch electrode 28 and a predetermined electric circuit pattern 29 are formed by printing means.

And upper pattern film 22. The spacer 25 and the lower pattern film 27 are laminated to form respective first switch electrodes 23 . Opening hole 26. The centers of the second switch electrodes 28 are aligned and fixed on the same axis. Further, the electric circuit patterns 24 and 29 are electrically connected to an electric circuit (not shown) by a connector (not shown).

Next, we will discuss the actions of the rubber spring lO and membrane switch 21 having such a configuration.

This will be explained with reference to the respective operation state diagrams shown in FIGS. 3A to 3F.

By comparing the two figures, Fig. 3A shows the state when no pressure is applied, and Fig. 3B shows the state immediately after the suppression operation starts.
Immediately after the rubber spring IO starts to be pressed, the bent portion 12c of the side wall portion 12 receiving the suppressing load is deformed so as to bulge outward.

In the state shown in FIG. 3C where the load is slightly increased from this state, the bending portion 12c bulges outward and the upper portion 12
A and the lower portion 12b continue to deflect, and immediately after this, a so-called click point is reached where the load state is reversed.

That is, when the load increases continuously from the state shown in FIG. 3B to the state shown in FIG.
2c to press the lower part 12b laterally, while the lower part 12b receives a lateral elastic resistance from the lower part 12b and receives a force that causes it to bend inward, and in relation to this, it also bends. As a result of the outward expansion of the portion 12c, the upper portion 12a and the lower portion l? The mechanical balance between the upper part 12a and the bending part 12c is lost, and most of the pressing load is directed towards bending the upper part 12a and the bent part 12c, and the pressing load, which had been continuously increasing, is A click point is reached where the change gradually decreases, and this cool sensation provides a suitable tactile effect to the fingertip.

In the state immediately after this click point, as shown in the third diagram, the outward bulge of the bent portion 12c and the bending of the lower portion 12b have returned from the extreme state, and the upper portion 12a and the bent portion 1
Only the bending phenomenon 2c is progressing. Further, the operating portion 14 has reached the height of the lower surface of the base portion 16, that is, the position where it is in contact with the upper surface of the upper pattern film 22 of the circuit pattern board 20.

FIG. 3E shows a state in which the annular top portion 11 is pressed further than this state, and in this state, each bending state of the bent portion 12c and the upper portion 12a progresses, and the upper portion 1
2a is completely buried between the lower portion 12b and the annular top portion 11, and the lower portion 12b is in a substantially vertical state. Then, as the operating part 14 is compressed, the thin inner wall part 13 subjected to the pressing load is bent and sinks into the annular top part 11, and the upper pattern film 22 is further pressed and bent, and the first switch electrode 23 is bent. It comes into contact with the second switch electrode 28 of the lower pattern film 27 and a key signal is output.

! FIG. 33F shows a pressing operation limit state in which the annular top 11 is pressed further than this state, and when the load is continuously increased after going through the state shown in FIG. 3E, the annular top 11 becomes As the inner wall portion 13 further descends, the bending phenomenon progresses as the inner wall portion 13 receives vertical elastic resistance from the operating portion 14, and immediately after this, the second load state is reversed, that is, the second click point is reached.

Immediately after this second click point, the lower surface of the inner wall portion 13 comes into contact with the upper part of the upper pattern film 22, resulting in a pressing operation limit state, and the first switch electrode 23 and the second switch electrode 28
The two are in pressure contact with each other.

Then, when the pressing load is removed in the state shown in Fig. 3 F,
Rubber spring 10 and upper pattern film 22
are restored in the reverse order to the above due to their respective elastic restoring forces, and the first switch electrode 23 is separated from the second switch electrode 28.In addition, each part of the rubber spring lO in the above-mentioned operations To give a supplementary explanation of the effect, since the side wall portion 12 is formed of a conical upper portion 12a, a cylindrical lower portion 12b, and an annular groove portion 15 at the lower portion, the lower portion 12b is resistant to the suppressing load. The bent portion 12c is tilted outward without being extremely deformed.
The upper part 12a can be supported via the upper part 12a.

Furthermore, since the upper portion 12a is bent and has flexibility,
The upper portion 12 can be easily deformed when the key 1 is pressed, thereby preventing deformation stress from concentrating on the bent portion 12c.
Since it is also dispersed in the rubber spring 10, it is possible to improve the fatigue resistance of the rubber spring 10 and extend its life. In addition, since the upper portion 12a can accumulate stress within its deformable limit when the key 1 is pressed, the operability of the key 1 can be improved.

In addition, the thin inner wall portion 13 that acts after the operating portion 14 contacts the upper pattern film 22 absorbs the pressing stroke accompanying its deformation, so that the position at the moment when the operating portion 14 contacts the upper pattern film 22 ( It evens out the load fluctuations from point R) to the moment when the switch electrode is in pressure contact (point T), suppresses the movement of the operating part 14, and maintains a stable load state even if there is vibration in the fingertips, etc. This is to suppress the occurrence of chattering by pressing the switch electrode.

Fig. 4 is a load-stroke characteristic curve diagram indicated by A-F corresponding to each operating state of Fig. 3 A''-F in the pressing operation of a key switch using one or more rubber springs 10. Changes in characteristics between the low load point R and the low load point T of this curve are mainly caused by the magnitude of the curvature of the cross-sectional shape of the inner wall 13 and the formation of a compound curve, or by the thickness of the entire or partial inner wall 13. It can be adjusted by increasing or decreasing the thickness.

The second load reversal point S and the load low point T are set to be located between the load values formed by the first load reversal point Q and the load low point R, thereby preventing the occurrence of chattering. can be effectively suppressed.

It should be noted that the present invention is not limited to the configuration of the above-described embodiments; for example, a pair of electrodes may be provided with a conductive rubber on the lower surface of the operating part or a soft elastic body with a conductive film on the lower surface. Even if the gap is electrically closed, similar actions and effects can be achieved.

Further, it goes without saying that the cross-sectional shape of the inner wall portion can be arbitrarily set as long as it forms the second load reversal point, such as a substantially doglegged shape.

<Effects of the Invention> As explained above, in the key switch of the present invention, the rubber spring responsible for the key action contacts the base portion that contacts the circuit pattern board and the lower surface of the key stem of the key that is guided and supported in the vertical direction. an annular top; an operating part located inside the annular top and intermediate between the annular top and the base; a side wall bulging outward that connects the base and the annular top; It consists of an inner wall that bulges outward and connects the inner wall.

Load fluctuations when the key switch is closed are leveled out, the movement of the movable parts is suppressed, the occurrence of chattering is suppressed, and the switch electrodes can be quickly brought into a stable closed state. Therefore, the device operates quickly when the key is manually operated, and the input operation feeling is improved.

In addition, there is less variation in the load on the fingertips when closing.

It is possible to provide a key switch that causes less fatigue even when operating a keyboard device for a long time.

Moreover, the effects that such a key switch can have, such as being able to be constructed without an increase in cost, are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a key switch according to an embodiment of the present invention.
Fig. 2 is an enlarged vertical sectional view of the rubber spring, Fig. 3 A-F is a diagram of each pressing operation state of the rubber spring, Fig. 4 is a load-stroke characteristic curve diagram of the rubber spring, and Fig. 5 is a conventional FIG. 3 is a load-stroke characteristic curve diagram of the key switch. l...Key, 3...Key stem. 4...Frame, lO...Rubber spring, 11...Annular top, 12...Side wall part, 13...Inner wall part, 14...Moving part. 20... Circuit pattern board, 23... First switch electrode, 28... Second switch electrode. @Figure 1 Figure 2 Figure 3 Figure A! I3 111nB#1
Figure 3 C @ Figure 3 D @ 3 Figure E Figure 3 Figure F Figure 4 Old Stroll Figure 5-〇

Claims (1)

[Claims] A circuit including a key whose key stem is vertically guided and supported by a frame, and a pair of electrodes that are normally electrically insulated, and where the two electrodes are electrically connected when the key is pressed. a pattern board; and an inverted cup-shaped rubber spring that is interposed between the key and the circuit pattern board and always holds the key in an inoperative position by its own elastic force; a base portion that comes into contact with the board; an annular top portion that comes into contact with the lower surface of the key stem of the key; and a thick disk-shaped operating portion that is located inside the annular top portion and located between the annular top portion and the base portion. It is characterized by comprising: a thin side wall portion that bulges outward and connects the base portion and the annular top portion; and a thin inner wall portion that bulges outward and connects the annular top portion and the operating portion. key switch.