JP2000200525A - Key switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To intend a key switch to be thin when a current is not carried and to extend its life. SOLUTION: In this key switch, provided are a key top 2, a contact type switch 20 that first and second contacts 18a and 19a are connected to be closed by pressure operation of the key top 2; a compression coil spring 4 of a shape memory alloy which a middle part 4b is brought into contact with the inside of the key top 2 and is heated up to a shape recover temperature to show super elasticity for holding the key top 2 in an operation set up position capable of pressure operation and which is deformed by pressure operation of the key top 2 to contact the first and second contacts 18a and 19a, an energizing means 31b for energizing the key top 2 in the direction closing to the contact type switch 20, a spring support means 5 for supporting the compression coil spring 4, and a key top support means 3 for movably supporting the key top 2 in the direction separating from the contact type switch 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a key switch. More specifically, the present invention relates to a technique for reducing the thickness and extending the life when electricity is not supplied.

[0002]

2. Description of the Related Art Various electronic devices, such as personal computers and word processors, are provided with a keyboard as an input device, and the keyboard is provided with a plurality of key switches.

FIGS. 18 and 19 show a conventional key switch.

The key switch a has a key top b and a coupler c connected to the center of the inner surface of the key top b. The coupler c has a connecting portion d, deformed portions e and e, and an attached portion. f, f and the pressing projection g are rich in elasticity, for example,
It is formed integrally with a rubber material.

The key switch a has an upper end of the connecting portion d connected to the inner surface of the key top b, and protrudes so that the deformed portions e and e are separated from each other as they go down from both side edges of the connecting portion d. The attached portions f, f are provided at the lower ends of the deformed portions e, e, and the pressing projection g is provided so as to project downward from the center of the lower surface of the connecting portion d.

A chassis h is arranged below the key switch a, and a first circuit board i and a second circuit board j are arranged vertically above and below the chassis h with a spacer (not shown) interposed therebetween. Have been. A first contact (not shown) and a second contact (not shown) are respectively provided on the first circuit board i and the second circuit board j.
The first contact and the second contact constitute a contact-type switch, and the contact-type switch is disposed directly below the pressing projection g of the key switch a. And
The contact type switch is closed by connecting the first contact and the second contact.

A mounting member k is provided on an upper surface of the first circuit board i.
k is provided, and mounting portions f, f of the key switch a are mounted on the mounting members k, k.

When the key top b is pressed downward, the deformed portions e, e of the cup rubber c are deformed,
The pressing projection g is moved downward (see FIG. 19). Then, the first circuit board i is moved by the downward movement of the pressing projection g.
Is pressed downward, whereby the first contact is connected to the second contact provided on the second circuit board j, and the contact switch is closed.

Conversely, in the state shown in FIG. 19, when the downward pressing operation of the key top b is released, the deformed portions e, e of the deformed cup rubber c return to the original state, and the pressing protrusion is formed. g is moved upward, the first contact and the second contact are separated, and the contact switch is opened. Then, the key switch a returns to the original state before the pressing operation of the key top b (see FIG. 18).

[0010]

However, in the above-mentioned conventional key switch a, the key top b is always in the state of the cup rubber c when no pressing operation is performed.
, And the width of the key switch a in the height direction, that is, the thickness of the key switch a increases accordingly, which hinders the thinning of the electronic device using the key switch a.

Further, when the key top b is pressed, the deformed portions e and e of the cup rubber c are deformed and a very large stress is generated, so that there is a problem that the life of the cup rubber c is short.

Further, when the coupler rubber c is heated, a toxic gas may be generated.
There is also a key switch a
There is also a problem in that the manufacturing cost increases.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above-mentioned problems, to reduce the thickness of the battery when power is not supplied, and to extend the life of the battery.

[0014]

The key switch of the present invention comprises:
In order to solve the above-mentioned problem, the first contact and the second contact are configured by a key top to be pressed, a first contact and a second contact, and the first contact and the second contact are connected by the pressing operation of the key top. A contact type switch that is closed and closed, and an intermediate part made of a shape memory alloy contacts the inner surface of the key top and is heated to the shape recovery temperature by energization to exhibit superelasticity, and the key top can be pressed against the key top A compression coil spring which is held in a proper operation preparation position and is deformed by a pressing operation on the key top to connect the first contact and the second contact, and a biasing force for biasing the key top in a direction approaching the contact type switch Means, spring support means for supporting both ends of the compression coil spring, and key top support means for movably supporting the key top in the direction of contacting and separating from the contact type switch.

According to another aspect of the present invention, there is provided a key switch comprising: a key top to be pressed; a first contact and a second contact; A contact type switch in which the first contact and the second contact are connected to each other to be closed, and a switch made of a shape memory alloy, one end of which is attached to the inner surface of the key top and heated to a shape recovery temperature by energization to be superelastic A compression coil spring that holds the key top at an operation preparation position where the key top can be pressed, and is deformed by the pressing operation on the key top to connect the first contact and the second contact; A biasing means for biasing the top in a direction approaching the contact type switch, a spring supporting means for supporting both ends of the compression coil spring, and a key top movable in a direction in which the key top is moved toward and away from the contact type switch. It is provided with a key tops support means for lifting.

Therefore, in the key switch of the present invention,
No coupling rubber is required, and the state where the key top is close to the contact type switch when power is not supplied is maintained.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the key switch according to the present invention will be described with reference to the accompanying drawings. In the embodiment described below, the key switch of the present invention is applied to a key switch provided on a keyboard of a personal computer.

First, the key switch 1 according to the first embodiment shown in FIGS. 1 to 12 will be described.

An electronic device such as a personal computer includes a main body having a keyboard provided as an input device, and a liquid crystal display functioning as a display device rotatably supported at one end of the main body. There are things.
A keyboard provided in such a personal computer has a plurality of key switches 1, 1,... (See FIGS. 1 to 3).

The key switch 1 has a key top 2, a link mechanism 3 provided as key top support means, a compression coil spring 4, spring support means 5 for supporting the compression coil spring 4, and a link support mechanism 6. (See FIGS. 4 and 5).

The key top 2 is provided with a projection 2a projecting downward at the center of the inner surface thereof, and the projection 2a is formed in a triangular shape having a transverse cross section and projecting downward. First support portions 7, 7 are provided at positions near the front end of the inner surface of the key top 2 so as to be separated from each other in the left and right directions.
At the position near the rear end of the inner surface, second support portions 8, 8 are provided to be separated from each other in the left and right directions.

Each of the first support portions 7 and 7 is integrally formed with a vertical portion 7a protruding downward and a horizontal portion 7b protruding in a direction approaching each other from a part of a lower edge of the vertical portion 7a. Consisting of The second support portions 8, 8 each include a front side portion 8a and a rear side portion 8b which project downward and are slightly separated from each other in the front and rear directions.
A shaft insertion portion 8c is formed by forming a notch formed in an arc surface at the lower end of b.

The link mechanism 3 comprises a first member 9 and a second member 10 rotatably connected to each other.

The first member 9 has a base 11 extending in the left-right direction.
And intermediate portions 12 and 12 projecting downward from both left and right ends of the base portion 11 and supported portions 13 and 13 projecting further downward from outer ends of the intermediate portions 12 and 12 are integrally formed. Become. Sliding shafts 11a, 11a protruding outward are formed at the upper ends of the left and right sides of the base 11, and the supported protruding outwards are formed at the lower ends of the outer surfaces of the supported portions 13, 13. Shafts 13a, 13a are formed.

The second member 10 has a base 1 extending in the left-right direction.
4, intermediate portions 15, 15 protruding downward from both left and right ends of the base portion 14, supported portions 16, 16 protruded further downward from outer ends of the intermediate portions 15, 15, and the supported portion 1
6, a spring receiving portion 17 continuously provided at the lower end of
17 are integrally formed. A support shaft 14a protruding outward is provided at the upper end of the left and right side surfaces of the base 14.
14a is formed, and supported shafts 16a, 16a protruding inward are formed at lower ends of the inner surfaces of the supported portions 16, 16, respectively.

In the first member 9 and the second member 10, a connecting pin formed in the intermediate portion 15 is inserted into a connecting hole formed in the intermediate portion 12, whereby the first member 9 and the second member 10 are inserted. The member 10 is rotatably connected to each other. By being connected in this manner, the link mechanism 3 is such that the first member 9 and the second member 10 cross each other when viewed from the side, and the rear edge of the base 11 and the front edge of the base 14 Intermediate part 12, 1
A space for inserting a part of the compression coil spring 4 surrounded by each inner edge of the coil spring 5 is formed.

The link mechanism 3 includes a sliding shaft 1 of the first member 9.
1a and 11a are the inner surface of the key top 2 and the horizontal portions 7b and 7b.
The support shafts 14a, 14a of the second member 10 are rotatably inserted into the shaft insertion portions 8c, 8c of the key top 2.

A chassis (not shown) is disposed below the link mechanism 3, and a first circuit board 18 and a second circuit board 19 each having a predetermined circuit pattern formed thereon are provided above the chassis with a spacer (not shown). Are arranged in a vertically stacked manner. And the first circuit board 18
For example, a flexible printed circuit board and a second
The circuit board 19 is a circuit board made of, for example, a glass epoxy material.

First circuit board 18 and second circuit board 1
9 have a first contact 18a and a second contact 19a, respectively.
And a first contact 18a and a second contact 19a constitute a contact switch 20, and the contact switch 20 is disposed directly below the protrusion 2a of the key top 2 (FIGS. 8 to 8). 10). The contact switch 20 is closed by connecting the first contact 18a and the second contact 19a, and the connected first contact 18a
The contact type switch 20 is opened when the connection between the switch and the second contact 19a is released. The first circuit board 18 has connection lines 18b, 18b,.
Are connected to a power supply circuit (not shown), and the second circuit board 19 is connected to a power supply circuit (not shown) via connection lines 19b, 19b,... (See FIG. 1).

The compression coil spring 4 is formed of a shape memory alloy exhibiting superelasticity when heated to a predetermined temperature, that is, a shape recovery temperature, and is made of nickel, titanium and copper materials. As the compression coil spring 4, for example, KIOKALL having a shape recovery temperature of about 50 ° C. to 70 ° C.
OY-T (trade name of Daido Steel Co., Ltd.) is used. Then, the compression coil spring 4 is under no load, that is,
When no external force is applied, both ends 4a,
The ring-shaped portions 4a of the intermediate portion 4b are in contact with each other in the axial direction, and the ring-shaped portions of the intermediate portion 4b are separated in the axial direction (FIG. 4).
reference).

The spring support means 5 includes a first support portion 21 and a second support portion 2 each formed of a conductive metal material.
2, the first support 21 and the second support 22 are arranged to be separated from each other in the front and rear. The spring supporting means 5 serves not only to support the compression coil spring 4 but also to serve as a first energizing means for energizing the compression coil spring 4 supported by the spring supporting means 5.

The first support portion 21 has a plate-shaped mounted portion 23 and a receiving portion 2 projecting upward from the rear end of the mounted portion 23.
4 and a first insertion support portion 25 projecting substantially rearward from the upper end of the front surface of the receiving portion 24 are integrally formed.

The mounted portion 23 is joined to a first connecting portion (not shown) of the second circuit board 19. The front surface of the receiving portion 24 is formed as a gentle curved surface 24a that projects substantially rearward, and the upper end portion of the curved surface 24a faces substantially rearward and obliquely upward (see FIGS. 8 to 10).

The first insertion support portion 25 is formed in a block shape and has a substantially rectangular cross section, and its lower surface is formed as an inclined surface 25a that is displaced upward as it goes backward. The first insertion support portion 25 is slightly smaller than the opening area of the end surface of the compression coil spring 4 in the axial direction. That is, as shown in FIG.
5 is the width H1 of the compression coil spring 4 in the left-right direction.
And the vertical width H2 of the tip of the first insertion support portion 25 is 50% to 90% with respect to the inner diameter D of the compression coil spring 4. Is formed.

The second support portion 22 has a plate-like mounted portion 26 and a receiving portion 2 projecting upward from the front end of the mounted portion 26.
7 and a second insertion support portion 28 protruding substantially forward from the upper end of the front surface of the receiving portion 27.

The mounted portion 26 is joined to a second connecting portion (not shown) of the second circuit board 19. The surface of the receiving portion 27 facing the first support portion 21 is formed so as to face forward (see FIGS. 8 to 10).

The second insertion support portion 28 is formed in a block shape and has a substantially rectangular cross section, and its lower surface is formed as an inclined surface 28a which is displaced upward as it goes forward. The second insertion support portion 28 is considerably smaller than the opening area of the end face in the axial direction of the compression coil spring 4. That is, as shown in FIG. 7, the second insertion support portion 28 is formed such that the width H3 in the left-right direction is 30% to 70% with respect to the inner diameter D of the compression coil spring 4.
Further, the width H4 of the distal end of the second insertion support portion 28 is formed to be 30% to 70% of the inner diameter D of the compression coil spring 4.

A contact spring 29 attached to the first circuit board 18 is disposed between the first support 21 and the second support 22.

Insertion support portions 25 and 28 of the spring support means 5 are inserted into both ends 4a and 4a of the compression coil spring 4, respectively, whereby the compression coil spring 4 is supported by the spring support means 5. Then, in a state where the compression coil spring 4 is supported by the spring supporting means 5, both ends 4 a, 4 a and the attached parts 23, 26 are connected by the conducting wires 30, 30. Further, the energizing wires 30 and 30 function as second energizing means for energizing the compression coil spring 4.

The current-carrying wires 30, 30 are formed of a nickel material or a titanium material, and both ends thereof are provided at both ends 4a, 4a of the compression coil spring 4 and the mounting portion 2 of the spring supporting means 5.
3 and 26 by spot welding.

As described above, since the compression coil spring 4 is formed of a shape memory alloy, its temperature changes when it is energized, and it is deformed in accordance with this temperature change. It is also deformed when a pressing operation on 2 is performed. Therefore, when deformed, the support state of the compression coil spring 4 is changed with respect to the spring support means 5 functioning as the first energizing means, and the compression coil spring 4 is displaced with respect to the spring support means 5.

When the compression coil spring 4 is displaced with respect to the spring supporting means 5, the contact state of the compression coil spring 4 with the spring supporting means 5 changes, and
There is a possibility that power supply failure may occur, but the key switch 1
As described above, since the conducting wires 30 and 30 functioning as the second conducting means are provided as described above, the conducting wires 30 and 30 are provided even when the conduction failure from the spring support means 5 to the compression coil spring 4 occurs. The current is reliably supplied to the compression coil spring 4 via. Therefore, by providing the energizing lines 30, 30, the reliability of energizing the compression coil spring 4 can be improved.

Further, since the current-carrying wires 30, 30 are formed of a nickel material or a titanium material as described above, the composition is close to that of the compression coil spring 4 made of nickel, titanium, and copper materials, and the compression coil spring 4 is formed by spot welding. The bonding property to the metal is extremely good, and the workability is improved. One end of each of the conducting wires 30, 30 is joined to the supported portions 13, 16 of the spring supporting means 5 by spot welding, but if the supported portions 13, 16 are plated with, for example, nickel, they are joined. The workability is improved, and the workability can be further improved.

As will be described later, when the compression coil spring 4 supported by the spring supporting means 5 is energized and the compression coil spring 4 reaches the shape recovery temperature, as shown in FIG. Super-elastic middle part 4b
Has a substantially circular arc shape that protrudes upward. The compression coil spring 4 is designed so that a predetermined resilient force is exhibited when the key top 2 shown in FIG. 8 is held at an operation preparation position where the key top 2 can be pressed. The actual axial length of the compression coil spring in the unloaded state is 10% of the axial length in the unloaded state.
About 20% longer.

As described above, the length of the actual compression coil spring 4 in the axial direction when no load is applied to the design value is set to 1
By forming the compression coil spring to be longer by 0% to 20%, a stable spring force of the compression coil spring 4 can be obtained even when the compression coil spring 4 has a settled spring.

The link support mechanism 6 includes upper and lower portions 31 and 31 and a lower portion 32, each formed of a plate-like metal material, which are vertically arranged on the first circuit board 18 (see FIGS. 4 and 4). 5).

The upper portions 31, 31 are respectively composed of a main portion 31a extending in the front-rear direction, a bias spring portion 31b protruding forward from a half outside the front end of the main portion 31a, and a main portion 31a.
And an L-shaped portion 31c protruding outward from the rear end portion. Then, the bias spring portions 31b, 3
1b is resiliently contacted with the spring receiving portions 17, 17 of the second member 10 of the link mechanism 3, and is formed as urging means for urging the key top 2 downward.

The lower portion 32 has a main surface portion 33 and an L-shaped portion 34,
34, front support portions 35, 35, connecting portions 36, 36, and rear support portions 37, 37 are integrally formed.

The main surface portion 33 has a concave shape opened rearward when viewed from above, and an L-shaped portion 34 extends from the rear end of the main surface portion 33.
34 protrudes outward. At a portion near the front end of the main surface portion 33, front support portions 35, 35 protruding upward from the outer edge thereof are provided, and the front support portions 35, 35 have front support holes 35a, 35a long in the front-rear direction. Is formed. Then, connecting portions 36, 36 projecting from the rear ends of the L-shaped portions 34, 34 in directions approaching each other are provided,
Rear support portions 37, 37 projecting upward from the inner edges of the connection portions 36, 36 are provided. Also, the rear support 3
Rear support holes 37a, 37a are formed in 7, 37, respectively.

In the link support mechanism 6, the main portions 31a, 31a of the upper portions 31, 31 and the L-shaped portions 31b, 31b are respectively formed by the rear half of the main surface portion 33 of the lower portion 32 and the L-shaped portion 3.
4 and 34, and the lower part 32 is the first circuit board 1
8 is mounted.

The link mechanism 3 supporting the key top 2 as described above is supported by the link support mechanism 6. The link mechanism 3 is configured such that the supported shafts 13 a of the first member 9 are respectively connected to the rear support holes 37 of the lower portion 32 of the link support mechanism 6.
a, 37a are inserted from the inside and rotatably supported,
The supported shafts 16a, 16a of the second member 10 are connected to the front support holes 35a, 35 of the lower portion 32 of the link support mechanism 6, respectively.
a is rotatably and slidably supported by being inserted from outside.

In the key switch 1, the link mechanism 3 is provided as key top supporting means for movably supporting the key top 2 in a direction of coming and going from the contact type switch 20, but as the key top supporting means. When the link mechanism is used, generally, the movement stroke of the key top can be reduced, and the use of the link mechanism 3 can reduce the thickness of the key switch 1.

When the link mechanism 3 is supported by the link support mechanism 6 as described above, the tips of the spring receiving portions 17 of the second member 10 of the link mechanism 3 are biased by the bias spring portions 31 b of the upper portion 31. 31b. Therefore,
The link mechanism 3 is urged by a biasing force of the bias spring portions 31b, 31b in such a direction that the height in the vertical direction is reduced, whereby the key top 2 supported by the link mechanism 3 is pressed.
Is held at a non-energized position near the contact type switch 20 located below unless the energization of the compression coil spring 4 is performed (see FIG. 3).

As described above, the key top 2 is urged downward via the link mechanism 3 by the urging force of the bias spring portions 31b provided as urging means, but is compressed by the spring supporting means 5. When the coil spring 4 is energized from the power supply circuit through the spring supporting means 5 (and the conducting wires 30 and 30) and the compression coil spring 4 reaches the shape recovery temperature, the compression coil spring 4 exhibits superelasticity and is upwardly convex. The intermediate portion 4b pushes the key top 2 upward by overcoming the biasing force of the bias spring portions 31b, 31b. Therefore, the key top 2 is
2 is held at an operation preparation position where a pressing operation can be performed.
And FIG. 8).

When the current is supplied to the compression coil spring 4 and the temperature reaches the shape recovery temperature while the key top 2 is held at the non-energized position, as described above, the compression coil spring 4 exhibits superelasticity. The energization of the compression coil spring is performed by turning on a power switch provided on the main body of the personal computer.

At this time, the compression coil spring 4 has both ends 4 a, 4 a of the first supporting portion 2 of the spring supporting means 5.
The first receiving portion 24 and the receiving portion 27 of the second supporting portion 22 are in elastic contact with each other, and the intermediate portion 4b can be displaced upward or downward by the spring force. The upper end of the curved surface 24a of the receiving portion 24 is formed so as to face substantially rearward and obliquely upward, and the insertion support portion 2 is formed.
Since the lower surfaces of the compression coil springs 5 and 28 are formed as inclined surfaces 25a and 28a which are displaced upward as they approach each other, the compression coil spring 4 is displaced in a direction according to these inclinations. 4 is an intermediate portion 4b of a compression coil spring 4 formed on the link mechanism 3.
Is inserted through the space, and the intermediate portion 4b is moved upward to form a substantially arc shape that is upwardly convex (see FIG. 8). Thereby, the middle part 4 of the compression coil spring 4
b comes into contact with the protrusion 2a, and the key top 2 is pushed upward through the protrusion 2a and held at the operation preparation position.

When the key top 2 is raised and lowered, which will be described later, the key top 2 is raised or lowered with the operation of the link mechanism 3. However, when the link mechanism 3 is operated, the sliding shaft of the link mechanism 3 is moved. 11a, 11a are slid between the inner surface of the key top 2 and the horizontal portions 7b, 7b of the first support portions 7, 7 and the supported shafts 16a, 16a of the link mechanism 3
Are slid in the front support holes 35a of the front support portions 35 of the link support mechanism 6.

The energization of the compression coil spring 4 is performed by PWM modulation pulse energization, and the initial current, that is, the current value of the starting current supplied to the compression coil spring 4 immediately after the start of energization, is supplied to the compression coil spring 4 after this starting current is supplied. It is higher than the current value of the supplied current. The wire diameter (diameter) is 0.
When the 35-mm compression coil spring 4 is used, for example, the starting current is 800 mA (duty ratio 0.5 in the P1 period shown in FIG. 11), and the current value after that is 600.
mA (duty ratio 0.1 during P2 period shown in FIG. 11)
5).

As described above, by setting the current value of the starting current higher than the current value of the subsequent current, the time T until the compression coil spring 4 reaches the shape recovery temperature shown in FIG.
1 is a very short time, the key top 2 is quickly moved from the non-energized position to the operation preparation position, and is very convenient for the operator of the key switch 1.

From the operation preparation position shown in FIG.
When the pressing operation is performed, the intermediate portion 4b of the compression coil spring 4 is pressed downward by the protrusion 2a, and the compression coil spring 4 is brought into a substantially horizontal state (see FIG. 9). When the key top 2 is further pressed downward from this state,
The compression coil spring 4 is in a state where the intermediate portion 4b projects downward (see FIG. 10).

When the compression coil spring 4 is displaced from the state shown in FIG. 8 to the state shown in FIG. 10 with the pressing operation on the key top 2, the direction of the spring force of the compression coil spring 4 is reversed halfway. Then, a click feeling is transmitted to the operator who presses the key top 2 by this inversion.

As described above, the first insertion support portion 25 of the spring support means 5 is formed such that the width H1 is 70% to 90% of the inner diameter D of the compression coil spring 4, and the width H2 is compressed. The second insertion support portion 28 is formed so that the width H3 and H4 are 30% to 70% of the inner diameter D of the compression coil spring 4 with respect to the inner diameter D of the coil spring 4. (See FIG. 6).
And FIG. 7). Therefore, when the key top 2 is pressed and the compression coil spring 4 is displaced, the end 4a of the compression coil spring 4 on the side supported by the first insertion support portion 25 is substantially fixed, and the compression is performed. The end 4a of the coil spring 4 on the side supported by the second insertion support portion 28 is movable. Thus, the compression coil spring 4
Of the compression coil spring 4 functions as a movable end, and the other end 4a of the compression coil spring 4 when the key top 2 is pressed. The compression coil spring 4 is displaced while moving freely with respect to the second insertion support portion 28, whereby the above-described reversal of the spring force of the compression coil spring 4 occurs, and a click feeling is generated.

FIG. 12 shows the relationship between the displacement of the compression coil spring 4 and the operating force (reaction force received by the operator via the key top 2 when the key top 2 is pressed). The relationship when the keytop 2 is pressed is shown by points S-point A1-point A2-point M. When the key top 2 is pressed, the operating force drops once at the inflection point A1, and then changes to the inflection point A2.
Then, it starts to rise again and reaches the peak point M. in this way,
The click feeling is transmitted to the operator by the operating force once decreasing from the inflection point A1 to the inflection point A2.

When the key top 2 is pressed and the intermediate portion 4b of the compression coil spring 4 is displaced so as to project downward, the contact spring 29 located below the intermediate portion 4b is pressed downward by the intermediate portion 4b (FIG. 10). reference). And
When the contact spring 29 is pressed, the first contact 18a formed on the first circuit board 18 and the second contact 19a formed on the second circuit board 19 are connected,
The opened contact type switch 20 is closed. When the contact switch 20 is closed, predetermined characters and the like are displayed on the liquid crystal display unit functioning as the display device of the personal computer.

The contact spring 29 is connected to the first contact 1
In addition to the role of connecting the second contact 8a and the second contact 19a, the second contact 19a also plays a role of absorbing the variation when the displacement of the compression coil spring 4 varies.

When the pressing operation on the key top 2 is released, the compression coil spring 4 is displaced so that the intermediate portion 4b projects upward to return to the original state at the time of energization, that is, the state shown in FIG. To go. Therefore, key top 2
Is pressed upward by the intermediate portion 4b of the compression coil spring 4, the key top 2 is pushed up, and is again held at the operation preparation position.

The relationship between the displacement of the compression coil spring 4 and the operating force from when the pressing operation on the key top 2 is released to when the compression coil spring 4 returns to the original state when energized is represented by a point M-point in FIG. It is represented by B-point S.

When energization of the compression coil spring 4 is stopped in a state where the key top 2 is in the operation preparation position,
The super-elastic state of the compression coil spring 4 is lost, and the key top 2 is lowered by the biasing force of the bias spring portions 31b, 31b of the link support mechanism 6, and is again held at the non-energized position.

As described above, the key switch 1 uses the compression coil spring 4 made of a shape memory alloy, and the key top 2 is held at the non-energizing position when the power is turned off. When the power is supplied to the key switch 4, the compression coil spring 4 is heated to the shape recovery temperature and exhibits superelasticity, and the key top 2 is held at the operation preparation position. Therefore, the thickness of the key switch 1 when the power is not supplied can be reduced.

In particular, the personal computer of the above-mentioned type in which the liquid crystal display unit functioning as a display device rotates with respect to the main unit having a keyboard provided as an input device, and the key switches 1, 1,... If you use
Normally, the key top only needs to be held in the operation preparation position and can be pressed only when the power is on when the power is turned on. The thickness of the computer can be reduced without causing the problem.

In the above-described key switch 1, since a relatively short-lived and expensive coupler is not used, the life of the key switch 1 can be extended and the manufacturing cost can be reduced. .

Furthermore, since the coupler is not used, there is an advantage that the problem of disposal processing when the coupler is used can be reduced.

Next, a key switch 1A according to a second embodiment shown in FIGS. 13 to 15 will be described.

The key switch 1A shown below differs from the above-described key switch 1 mainly in that the arrangement of the compression coil springs is different and that a tension coil spring is used as the urging means. Only the parts that are different mainly from the key switch 1 will be described in detail,
The other parts will be described briefly, or the same reference numerals will be given to the same parts as those of the key switch 1 and the description will be omitted.

The key switch 1A includes a key top 2A, a link mechanism 3A provided as key top support means, a compression coil spring 4A, a link support mechanism 6A, and a tension coil spring 38 provided as urging means.

The key top 2A is the same as the key top 2 described above except that the projection 2a is not provided. The link mechanism 3A is the same as the above-described link mechanism 3 except that the spring receiving portions 17 and 17 are not provided.

The compression coil spring 4A is similar to the above-described compression coil spring 4, and is formed of a shape memory alloy which exhibits superelasticity when heated to reach a shape recovery temperature. Between the end portions 4a and 4a of the compression coil spring 4A and the first connection portion (not shown) of the second circuit board 19 and the second connection portion (not shown) of the second circuit board 19, there are provided conducting wires 30A and 30A, respectively. Is connected by the conducting wire 30
A and 30A are coil-shaped and can be extended and contracted.

The extension coil spring 38 is a compression coil spring 4A.
Are arranged coaxially with the compression coil spring 4A (see FIG. 15). The compression coil spring 4A and the extension coil spring 38 are arranged so that the axial direction extends vertically, one end portions 4a and 38a are attached to the center of the inner surface of the key top 2, and the other end portions 4a and 38a are compression coil springs. It is attached to the upper surface of a contact spring 29A disposed immediately below the 4A and extension coil spring 38.

The key switch 1A is not provided with the spring supporting means 5 provided in the key switch 1. The link support mechanism 6A includes bias spring portions 31b, 31b.
It is the same as the above link support mechanism 6 except that b is not provided.

When the compression coil spring 4A is not energized, the key top 2A is held at the non-energized position near the contact type switch 20 located below the key top 2A by the spring force of the extension coil spring 38. Then, the energizing wires 30A, 30A are supplied from the power supply circuit to the compression coil spring 4A.
When the compression coil spring 4A reaches the shape recovery temperature, the compression coil spring 4A exhibits superelasticity and overcomes the spring force of the extension coil spring 38 to push the key top 2A upward. Therefore, the key top 2A is held at an operation preparation position where the key top 2A can be pressed (see FIG. 13).

The energization of the compression coil spring 4A is performed by PWM modulation pulse energization, and the current value of the starting current is the same as the energization of the compression coil spring 4 described above. It is higher than the current value. Therefore, the time until the compression coil spring 4A reaches the shape recovery temperature is very short,
The key top 2A is promptly moved from the non-energized position to the operation preparation position.

When the key top 2A is pressed at the operation preparation position, the key top 2A is moved downward, the compression coil spring 4A and the extension coil spring 38 are compressed, and the pressing force is transmitted to the contact spring 29A, and the first pressure is transmitted.
The first contact 18a formed on the second circuit board 19 and the second contact 19a formed on the second circuit board 19 are connected, and the open contact switch 20 is closed (FIG. 14). reference).

When the pressing operation on the key top 2A is released, the compression coil spring 4A is extended to return to the original state at the time of energization, that is, to the state shown in FIG. The coil spring 38 is also extended. Therefore, the key top 2A is held at the operation preparation position (see FIG. 13).

When the energization of the compression coil spring 4A is stopped while the key top 2A is in the operation preparation position, the super elastic state of the compression coil spring 4A is lost, and the key top 2A is lowered by the spring force of the extension coil spring 38. And is again held at the non-energized position.

In the key switch 1A, as in the case of the key switch 1, the compression coil spring 4A made of a shape memory alloy is used. When power is supplied to the coil spring 4A, the compression coil spring 4A is heated to the shape recovery temperature and exhibits superelasticity, and the key top 2A is held at the operation preparation position.
Can be made thinner.

Also, in the above-described key switch 1A, similarly to the key switch 1, the life of the key switch 1A can be extended and the manufacturing cost can be reduced since an expensive coupler having a relatively short life and no expensive rubber is used. Reduction can be achieved.

Further, since the coupler is not used, there is an advantage that the problem of disposal processing when the coupler is used can be reduced.

In the key switch 1A, similarly to the key switch 1, the key top 2A is connected to the contact type switch 20.
Since the link mechanism 3A is provided as a key top supporting means for movably supporting the key switch 1A in a direction in which the key switch 2A can be moved away from the key switch 1A, the moving stroke of the key top 2A can be reduced, and the key switch 1A can be further thinned. .

Further, in the key switch 1A, since the compression coil spring 4A and the extension coil spring 38 are coaxially arranged, the arrangement space can be reduced as compared with the case where these are separately arranged. The size of the switch 1A can be reduced.

Next, a key switch 1B according to a third embodiment shown in FIGS. 16 and 17 will be described.

The key switch 1B shown below is different from the above-mentioned key switch 1A mainly in that the shape of the key top is different and that another mechanism is used as the key top support means without using a link mechanism. Therefore, only the parts that are different from the key switch 1A will be mainly described in detail, and the other parts will be described briefly, or the same reference numerals as those in the key switch 1A will be used. The same reference numerals are given and the description is omitted.

The key switch 1B includes a key top 2B, a support cylinder 39 provided as key top support means, a compression coil spring 4B, and a tension coil spring 38 provided as urging means.

The key top 2B is provided with a supported cylinder 40 projecting downward from the inner surface thereof. The key switch 1B is not provided with a link mechanism.

The compression coil spring 4B is similar to the above-described compression coil spring 4A, and is formed of a shape memory alloy that exhibits superelasticity when heated to reach a shape recovery temperature. The extension coil spring 38 is arranged inside the compression coil spring 4B coaxially with the compression coil spring 4B. The compression coil spring 4B and the extension coil spring 38 are arranged so that the axial direction extends vertically, and one end 4
a and 38a are attached to the center of the inner surface of the key top 2, and the other ends 4a and 38a are attached to the upper surface of a contact spring 29B disposed immediately below the compression coil spring 4A and the extension coil spring 38.

The key switch 1B includes the first circuit board 18
A support cylinder 39 is disposed on the upper surface of the key top 2B, and the support cylinder 39 is formed to be slightly larger than the supported cylinder 40 of the key top 2B. A supported cylinder 40 is supported by the support cylinder 39 so as to be vertically movable.

When the compression coil spring 4B is not energized, the key top 2B is held at the non-energized position near the contact type switch 20 located below the key top 2B by the spring force of the extension coil spring 38. Then, the energizing wires 30B, 30B are supplied from the power supply circuit to the compression coil spring 4B.
When the compression coil spring 4B reaches the shape recovery temperature, the compression coil spring 4B exhibits superelasticity and overcomes the spring force of the extension coil spring 38 to push the key top 2B upward. Therefore, the key top 2B is held at the operation preparation position where the key top 2B can be pressed (see FIG. 16).

The energization of the compression coil spring 4B is carried out by PWM modulation pulse energization. Like the above-described compression coil springs 4 and 4A, the current value of the starting current is determined by the current value of the current supplied to the compression coil spring 4B after the supply of the starting current. It is higher than the current value. Therefore, the time until the compression coil spring 4B reaches the shape recovery temperature is very short,
The key top 2B is promptly moved from the non-energized position to the operation preparation position.

When the key top 2B is pressed in the operation preparation position, the key top 2B is moved downward, the compression coil spring 4B and the extension coil spring 38 are compressed, and the pressing force is transmitted to the contact spring 29B, and the first pressure is transmitted.
The first contact 18a formed on the second circuit board 19 and the second contact 19a formed on the second circuit board 19 are connected, and the opened contact switch 20 is closed (FIG. 17). reference).

When the pressing operation on the key top 2B is released, the compression coil spring 4B is extended to return to the original state at the time of energization, that is, the state shown in FIG. The coil spring 38 is also extended. Therefore, the key top 2B is held at the operation preparation position (see FIG. 16).

When the energization of the compression coil spring 4B is stopped while the key top 2B is in the operation preparation position, the super elastic state of the compression coil spring 4B is lost, and the key top 2B is lowered by the spring force of the extension coil spring 38. And is again held at the non-energized position.

Thus, as with the key switch 1 and the key switch 1A, the thickness of the key switch 1B when power is not supplied can be reduced even in the key switch 1B.

Further, since an expensive coupler having a relatively short life is not used, the life of the key switch 1B can be extended and the manufacturing cost can be reduced.

Further, since the coupler is not used, there is an advantage that the problem in disposal processing when the coupler is used can be reduced.

In addition, since the compression coil spring 4B and the extension coil spring 38 are coaxially arranged in the key switch 1B, as in the key switch 1A, the arrangement space is smaller than when these are separately arranged. The size of the key switch 1B can be reduced accordingly.

The specific shape and structure of each part shown in each of the above embodiments are merely examples of the embodiment of the present invention, and the present invention is not limited thereto. Should not be construed as limiting the technical scope of the present invention.

[0106]

As is apparent from the above description, the key switch of the present invention comprises a key top to be pressed, the first contact and the second contact, and the key top is pressed. And a contact type switch in which the first contact and the second contact are connected to each other to be closed, and an intermediate portion made of a shape memory alloy is brought into contact with the inner surface of the keytop and heated to a shape recovery temperature by energization to obtain superelasticity. A compression coil spring that holds the presented key top at an operation ready position where the key top can be pressed and is deformed by the pressing operation on the key top to connect the first contact and the second contact; Biasing means for biasing the switch toward the contact type switch, spring supporting means for supporting both ends of the compression coil spring, and a key top which can be moved in a direction of separating from and coming into contact with the contact type switch. Characterized by comprising a key top support means for lifting.

Therefore, when power is not supplied, the key top is held at a position close to the contact type switch (non-powered position). When power is supplied to the compression coil spring, the compression coil spring is heated to the shape recovery temperature and exhibits superelasticity. Position where the top is far from the contact type switch (operation preparation position)
, The thickness of the key switch when power is not supplied can be reduced.

In particular, a key switch is attached to the main body of an electronic device in which the display is rotatably supported with respect to the main body and the display which has closed the main body only during use when power is supplied. If used, the key top only needs to be in a state where the key top is protruded and the pressing operation is possible only at the time of use. Therefore, the thickness of the key switch at the time of de-energization does not cause inconvenience in using the electronic device. Can be made thinner.

Further, since an expensive coupler having a relatively short life is not used, the life of the key switch can be extended and the manufacturing cost can be reduced.

Furthermore, since the coupler is not used, there is an advantage that the problem of disposal processing when the coupler is used can be reduced.

In addition, since the structure is relatively simple, the manufacturing cost does not increase, the arrangement space can be reduced, and the defective rate at the time of manufacturing can be reduced.

According to the second aspect of the present invention, the current value of the starting current flowing until the temperature reaches the shape recovery temperature at the start of energization of the compression coil spring is maintained, and the shape recovery temperature is maintained after the supply of the starting current. Therefore, the time required for the compression coil spring to reach the shape recovery temperature is very short because the current value of the current flowing to the compression coil spring is larger than the current value. This is very convenient for the operator of the key switch.

According to the third and fourth aspects of the present invention, the spring supporting means is provided as first energizing means for supplying a current to the compression coil spring, and the first means for supplying a current to the compression coil spring is provided. Since an energizing wire having one end connected to the compression coil spring is provided as the energizing means, even if a failure in energization from the spring support means to the compression coil spring occurs when the compression coil spring is displaced, the compression coil spring is connected to the compression coil spring via the energizing wire. The current is reliably supplied, and the reliability of energization of the compression coil spring can be improved.

According to the fifth and sixth aspects of the present invention, since the current-carrying wire is formed of a nickel material or a titanium material, the composition is close to that of a compression coil spring formed of a shape memory alloy, and the compression coil spring is formed. Has extremely good bonding properties.

According to the seventh aspect of the present invention, the axial direction of the compression coil spring in a no-load state designed so that a predetermined elastic force is exerted while the key top is held in the operation preparation position. The length in the axial direction of the compression coil spring under no load is 10% to 20%
%, The stable spring force of the compression coil spring can be obtained even when the compression coil spring has a so-called spring set.

In the invention according to the eighth aspect, since the link mechanism connected to the key top is provided as the key top support means, the moving stroke of the key top can be reduced, and the key switch can be further improved. Can be made thinner.

Further, another key switch of the present invention comprises a key top to be pressed, a first contact and a second contact, and the first key switch is operated by pressing the key top.
And a contact type switch which is closed by connecting the first contact and the second contact, and one end made of a shape memory alloy is attached to the inner surface of the key top and heated to the shape recovery temperature by energization to exhibit superelasticity. A compression coil spring that holds the top at an operation ready position where the key top can be pressed and is deformed by the pressing operation on the key top to connect the first contact and the second contact; Biasing means for biasing in the direction approaching the type switch, spring supporting means for supporting both ends of the compression coil spring, and key top supporting means for movably supporting the key top in a direction to be separated from and contacted with the contact type switch. It is characterized by having.

Therefore, when power is not supplied, the key top is held at a position close to the contact type switch (non-power supply position), and when power is supplied to the compression coil spring, the compression coil spring is heated to the shape recovery temperature to exhibit superelasticity. Position where the top is far from the contact type switch (operation preparation position)
, The thickness of the key switch when power is not supplied can be reduced.

In particular, a key switch is attached to the main body of an electronic device in which the display is rotatably supported with respect to the main body and the display is closed only during use when power is supplied. If used, the key top only needs to be in a state where the key top is protruded and the pressing operation is possible only at the time of use. Therefore, the thickness of the key switch at the time of de-energization does not cause inconvenience in using the electronic device. Can be made thinner.

Further, since an expensive coupler having a relatively short life is not used, the life of the key switch can be extended and the manufacturing cost can be reduced.

Further, since the coupler is not used, there is an advantage that the problem in disposal processing when the coupler is used can be reduced.

In addition, since the structure is relatively simple, the manufacturing cost does not increase, the arrangement space can be reduced, and the defective rate at the time of manufacturing can be reduced.

According to the tenth aspect of the present invention, the current value of the starting current flowing until the temperature reaches the shape recovery temperature at the start of energization of the compression coil spring is maintained, and the shape recovery temperature is maintained after the supply of the starting current. Therefore, the time required for the compression coil spring to reach the shape recovery temperature is very short because the current value of the current flowing to the compression coil spring is larger than the current value. This is very convenient for the operator of the key switch.

According to the eleventh aspect of the present invention, since the link mechanism connected to the key top is provided as the key top support means, the moving stroke of the key top can be reduced, and the key switch can be further improved. Can be made thinner.

According to the twelfth aspect of the present invention, since the urging means is arranged inside the compression coil spring, the arrangement space is smaller than when the urging means and the compression coil spring are separately arranged. As a result, the size of the key switch can be reduced accordingly.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the key switch of the present invention together with FIGS. 2 to 12, and is a plan view showing a plurality of key switches arranged on a circuit board.

FIG. 2 is a schematic side view showing a state in which key tops of a plurality of key switches arranged on a circuit board are held at an operation preparation position.

FIG. 3 is a schematic side view illustrating a state in which key tops of a plurality of key switches arranged on a circuit board are held at a non-energized position.

FIG. 4 is an enlarged exploded perspective view of the key switch.

FIG. 5 is an enlarged perspective view of a key switch.

FIG. 6 is a conceptual diagram showing the relationship between the inner diameter of a compression coil spring and the size of a first insertion support portion of a first support portion.

FIG. 7 is a conceptual diagram showing the relationship between the inner diameter of a compression coil spring and the size of a second insertion support portion of a second support portion.

8 shows the operation of the key switch together with FIGS. 9 and 10, and FIG. 8 is an enlarged side view partially showing a state in which the key top is held at the operation preparation position.

FIG. 9 is an enlarged side view partially showing a cross section of a state in which the key top is being pressed and the key top is being moved downward.

FIG. 10 is an enlarged side view partially showing a state in which a key top is moved downward and a contact type switch is closed.

FIG. 11 is a graph showing a relationship between an energizing time and a temperature of the compression coil spring when energizing the compression coil spring, and a duty ratio.

FIG. 12 is a graph showing the relationship between the amount of displacement and the operating force when the compression coil spring is displaced.

13 shows a second embodiment of the key switch of the present invention together with FIG. 14 and FIG. 15, and is an enlarged view partially showing a state in which the key top is held at the operation preparation position. It is a side view.

FIG. 14 is an enlarged side view showing a state in which the key top is moved downward and the contact type switch is closed, with a partial cross section.

FIG. 15 is an enlarged side view partially showing a cross section of an arrangement state of a compression coil spring and a tension coil spring.

FIG. 16 shows a third embodiment of the key switch of the present invention together with FIG. 17, and is an enlarged side view partially showing a state in which the key top is held at the operation preparation position. is there.

FIG. 17 is an enlarged side view partially showing a cross section of a state in which the key top is moved downward and the contact type switch is closed.

18 shows a conventional key switch together with FIG. 19, and is an enlarged sectional view showing a state before a keytop is pressed.

FIG. 19 is an enlarged sectional view showing a state where a keytop is pressed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Key switch, 2 ... Key top, 3 ... Link mechanism (key top support means), 4 ... Compression coil spring, 4a ...
End part, 4b middle part, 5 ... spring support means (first energizing means), 18a ... first contact, 19a ... second contact, 20
... contact type switch, 30 ... energizing wire (second energizing means),
31b: bias spring portion (biasing means), 1A: key switch, 2A: key top, 3A: link mechanism (key top support means), 4A: compression coil spring, 38: tension coil spring (biasing means), 1B: key Switch, 2B key top, 4B compression coil spring, 39 support tube (key top support means)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Masato Nishikawa, Inventor 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Osamu Kamijima 6-5-5, Togoe, Shinagawa-ku, Tokyo F-term in SMC Corporation (reference) 5G006 AA01 BA01 BA03 BB01 BB05 CB01 CD02 CD07 DD12

Claims (12)

[Claims] 1. A key top to be pressed and a first contact and a second contact, and the first contact and the second contact are connected and closed by a pressing operation of the key top. A contact type switch, which is made of a shape memory alloy, and an intermediate portion in contact with the inner surface of the key top, is heated to a shape recovery temperature by energization, exhibits superelasticity, and is in an operation ready position where the key top can be pressed against the key top. And a biasing means for biasing the keytop in a direction approaching the contact switch, the compression coil spring being deformed by a pressing operation on the keytop and connecting the first contact and the second contact. A key switch comprising: a spring supporting means for supporting both ends of a coil spring; and a key top supporting means for movably supporting a key top in a direction of moving away from or contacting the contact type switch. Ji. 2. The method according to claim 1, further comprising: determining a current value of a starting current to be supplied to the compression coil spring until the temperature reaches a shape recovery temperature at the start of energization. The key switch according to claim 1, wherein the current value is larger than the current value. 3. An energizing wire having one end connected to the compression coil spring as second energization means for supplying current to the compression coil spring, wherein the spring support means is provided as first energization means for supplying current to the compression coil spring. The key switch according to claim 1, further comprising: 4. An energizing wire having one end connected to the compression coil spring as a second energization means for supplying a current to the compression coil spring, wherein the spring support means is provided as first energization means for supplying an electric current to the compression coil spring. The key switch according to claim 2, further comprising: 5. The key switch according to claim 3, wherein said conductive wire is formed of a nickel material or a titanium material. 6. The key switch according to claim 4, wherein said energizing wire is formed of a nickel material or a titanium material. 7. When no load is applied to the axial length of the compression coil spring in a non-load state designed so that a predetermined elastic force is exerted while the key top is held in the operation preparation position. 2. The key switch according to claim 1, wherein the length in the axial direction of the compression coil spring in the state of (1) is increased by 10% to 20%. 8. The key switch according to claim 1, wherein a link mechanism connected to the keytop is provided as the keytop support means. 9. A key top to be pressed, a first contact and a second contact, and the first contact and the second contact are connected and closed by a pressing operation of the key top. A contact type switch, which is made of a shape memory alloy, one end of which is attached to the inner surface of the key top and heated to a shape recovery temperature by energization to exhibit superelasticity, and an operation preparation capable of pressing the key top to the key top A compression coil spring that is held in position and deformed by a pressing operation on the key top to connect the first contact and the second contact; and urging means for urging the key top in a direction approaching the contact switch, A key system comprising: spring support means for supporting both ends of a compression coil spring; and key top support means for movably supporting a key top in a direction in which the key top is separated from and brought into contact with the contact type switch. Pitch. 10. A current value of a start-up current to be supplied to a compression coil spring until the temperature reaches a shape recovery temperature at the start of energization,
10. The key switch according to claim 9, wherein the value of the current flowing through the compression coil spring is set to be larger than a value of the current flowing through the compression coil spring in order to maintain the shape recovery temperature after the supply of the starting current. 11. The key switch according to claim 9, wherein a link mechanism connected to the keytop is provided as the keytop support means. 12. The key switch according to claim 9, wherein said urging means is disposed inside a compression coil spring.