JP2022044831A - Reaction force generating member and key switch device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reaction force generating member and a key switch device capable of satisfactorily matching operation feeling and contact pressing operation even when a corner of an operation member is pressed.

SOLUTION: A dome rubber 15 as a reaction force generating member includes an outer dome portion 15b that applies a reaction force to a key top 10 in response to depression of the key top 10, a hemispherical bowl portion 15e disposed inside the outer dome portion 15b, and an inner dome portion 15d having a protruding portion 15f that protrudes downward from the center of the bowl portion 15e and pushes down a contact 14d disposed below the key top 10.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a reaction force generating member and a key switch device.

Conventionally, a dome rubber provided between an outer dome portion that is arranged between a membrane sheet and a key top and applies a reaction force according to elastic deformation to the key top, and an inner dome portion that presses a contact point of the membrane sheet. A key switch device using the above is known (for example, Patent Document 1).

In this key switch device, the operating force increases until the load acting on the outer dome portion of the dome rubber reaches the buckling load of the outer dome portion. When the load acting on the outer dome portion reaches the buckling load of the outer dome portion, the operating force gradually decreases as the keystroke increases. Then, in the process of reducing the operating force, the contacts of the membrane sheet are turned on. Therefore, the operator obtains a click feeling by obtaining a peak (maximum) operating force by buckling deformation of the outer dome portion. After that, while the operating force is decreasing, the inner dome presses the membrane sheet and the contacts of the membrane sheet are turned on, so the operation feeling and the contact pressing operation correspond well, and the operability of the key switch is improved. improves.

Japanese Patent Application Laid-Open No. 2015-133309

However, in the key switch device of Patent Document 1, since the key top is tilted when the corner of the key top is pressed, the load is not evenly applied to the outer dome portion and the inner dome portion. Therefore, the inner dome portion may buckle and deform. When the inner dome portion buckles and deforms, the desired load characteristics of the dome rubber cannot be obtained, and a gap occurs between the operation feeling and the contact pressing operation, which causes a sense of discomfort to the operator.

An object of the present invention is to provide a reaction force generating member and a key switch device capable of making a good correspondence between an operation feeling and a contact pressing operation even when a corner of the operating member is pressed.

The reaction force generating member described in the present specification includes a first dome portion that applies a reaction force to the operating member in response to pressing of the operating member, and a hemispherical bowl arranged inside the first dome portion. The first dome portion is provided with a second dome portion having a portion and a protrusion portion that protrudes downward from the center of the bowl portion and presses a switch arranged below the operating member, and the first dome portion buckles and deforms. The second dome portion does not buckle and deform, and the protrusion comes into contact with the switch at the same time as the first dome portion buckles or immediately after the buckling deformation.

According to the present invention, even when the corner of the operating member is pressed, the operation feeling and the contact pressing operation can be satisfactorily matched.

(A) is an exploded perspective view illustrating the key switch device according to the present embodiment. (B) is a diagram showing a computer including a keyboard in which a plurality of key switch devices of FIG. 1 (A) are arranged. (A) is a cross-sectional view of a dome rubber according to the present embodiment. (B) is a cross-sectional view of a dome rubber according to a comparative example. (A) is a figure which shows the load displacement characteristic of the dome rubber which concerns on this embodiment. (B) is a figure which shows the load displacement characteristic of the dome rubber which concerns on a comparative example. (A) to (D) are diagrams showing the transition state of the deformation of the dome rubber according to the present embodiment. (E) to (H) are diagrams showing the transition state of the deformation of the dome rubber according to the comparative example. (A) is a figure which shows the deformed state of the dome rubber which concerns on this embodiment when a key top is tilted. (B) is a diagram showing a deformed state of the dome rubber according to a comparative example when the key top is tilted and the inner dome portion is buckled and deformed. (C) is a figure which shows the deformed state of the dome rubber which concerns on the comparative example when the inner dome part is inverted.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1A is an exploded perspective view illustrating the key switch device according to the present embodiment. FIG. 1B is a diagram showing a computer including a keyboard in which a plurality of key switch devices of FIG. 1A are arranged. FIG. 2A is a cross-sectional view of the dome rubber according to the present embodiment, and FIG. 2B is a cross-sectional view of the dome rubber according to a comparative example.

As shown in FIG. 1A, the key switch device 100 includes a key top 10, two gear links 12a and 12b, a membrane sheet 14 and a support panel 17 that function as operating members. As shown in FIG. 1 (B), the keyboard 200 is configured by arranging a plurality of key switch devices 100. In the keyboard of FIG. 1B, one membrane sheet 14 and one support panel 17 corresponding to a plurality of key switch devices 100 are used.

As shown in FIG. 2A, the membrane sheet 14 has a sheet substrate 14b and 14c, a spacer 14e arranged between the sheet substrate 14b and the sheet substrate 14c, and a pair of contacts 14d functioning as a switch. I have. The sheet substrates 14b and 14c are separated by a predetermined distance via the spacer 14e. The contacts 14d are formed at positions where the spacer 14e is not provided so as to face each other. A dome rubber 15 as a reaction force generating member is fixed on the membrane sheet 14.

The dome rubber 15 is a dome-shaped member integrally molded from a rubber material, and has a ring-shaped base portion 15a, an outer dome portion 15b as a first dome portion extending diagonally upward from the base portion 15a, and an outer dome portion. It includes a cylindrical portion 15c extending vertically upward from 15b, and an inner dome portion 15d as a second dome portion protruding downward from the cylindrical portion 15c. The outer dome portion 15b functions as a reaction force generating portion, and the inner dome portion 15d functions as a contact pressing portion. The outer dome portion 15b is elastically deformed by a pushing force. The upper end of the cylindrical portion 15c comes into contact with the back surface of the key top 10.

The portion surrounded by the base portion 15a, the outer dome portion 15b, and the inner dome portion 15d is a space, and an air hole 18 is formed in the base portion 15a. The inner dome portion 15d includes a hemispherical bowl portion 15e extending downward from the cylindrical portion 15c, and a protruding portion 15f protruding downward from the center of the bowl portion 15e. Since the protrusion 15f is provided in the center of the bowl portion 15e, the center of the bowl portion 15e is thicker than the outer circumference of the bowl portion 15e. Therefore, when the protrusion 15f comes into contact with the membrane sheet 14 and the key top 10 is pushed in, the bowl 15e deforms upward, but the protrusion 15f does not bend and does not buckle. In the present embodiment, the buckling deformation is a deformation in which the load level decreases as the stroke increases. The cylindrical portion 15c has a recess 15g that accommodates the inner dome portion 15d (that is, the bowl portion 15e and the protrusion portion 15f that are deformed upward).

The dome rubber 150 of the comparative example shown in FIG. 2B has an inverted conical inner dome portion 15 m, and the cylindrical portion 15c of the dome rubber 150 has a recess 15n accommodating the inner dome portion 15 m. The dome rubber 15 and the dome rubber 150 differ in the shape of the inner dome portion and the recess, and have the same other structures.

The length L1 of the deformable portion (the portion from the cylindrical portion 15c to the protrusion 15f) of the inner dome portion 15d in FIG. 2A is the deformable portion (cylindrical portion 15c) of the inner dome portion 15m in FIG. 2B. The length from to the vertex X) is shorter than L2.

In the case of FIG. 2B, since the length L2 is longer than the length L1, if the left and right wall thicknesses of the inner dome portion 15 m differ depending on the finished mold, it is easily affected by non-uniform deformation. On the other hand, in the dome rubber 15 of FIG. 2A, since the protrusion 15f is provided in the center of the bowl portion 15e, the length L1 of the deformable portion of the inner dome portion 15d can be shortened. , Less susceptible to non-uniform deformation.

Further, as the stroke increases, the inner dome portion is stored in the recess while being stretched, so that the load applied to the deformable portion of the inverted conical inner dome portion 15 m in FIG. 2B is large, and the product of the dome rubber 150. The life may be shortened. Further, in the case of the dome rubber 150, if the key top 10 is pushed beyond the stroke end, the inner dome portion 15 m may be inverted and may not return to the shape shown in FIG. 2 (B). On the other hand, since the deformable portion of the inner dome portion 15d in FIG. 2A is bowl-shaped, the load can be reduced when the inner dome portion 15d is stored in the recess 15g, and inversion does not occur.

The upper surface 19a of the bowl portion 15e of the inner dome portion 15d in FIG. 2A has a spherical shape, and in particular, the upper surface 19b of the bowl portion 15e located above the protrusion 15f has a gentle spherical shape or a planar shape. This is because when the cross sections of the upper surface 19a and the upper surface 19b of the bowl portion 15e are V-shaped in FIG. 2B, the inner dome portion 15d is likely to buckle and deform, and the desired load displacement characteristic of the dome rubber 15 is obtained. This is because it cannot be obtained.

The length P2 from the upper surface 19b of the bowl portion 15e to the tip of the protrusion 15f shown in FIG. 2A is shorter than the length P3 from the upper surface 19b of the bowl portion 15e to the upper end of the cylindrical portion 15c. Further, the horizontal length P4 of the upper surface 19b of the bowl portion 15e is shorter than the inner diameter length P5 of the cylindrical portion 15c. These are for accommodating the inner dome portion 15d in the recess 15g and ensuring a longer stroke.

Returning to FIG. 1 (A), the support panel 17 is arranged under the key top 10, and the membrane sheet 14 is arranged between the key top 10 and the support panel 17. The upper surface of the support panel 17 faces the lower surface of the membrane sheet 14. The support panel 17 includes four regulating portions 17a that regulate the vertical movement of the shafts 12c of the gear links 12a and 12b. Each regulating portion 17a is formed perpendicular to the support panel 17 and includes a substantially rectangular hole 17b into which a shaft 12c that moves in the horizontal direction is inserted. A part of the upper surface of the support panel 17 and the regulating portion 17a are exposed from the holes 14a provided in the membrane sheet 14.

As shown in FIG. 1A, protrusions 12e are formed on the tip portions 12d of the gear links 12a and 12b, and the protrusions 12e are rotatably fixed to the back surface of the key top 10. A shaft 12c is formed at the rear ends of the gear links 12a and 12b, and the shaft 12c is inserted into the hole 17b of the regulating portion 17a. As a result, the gear links 12a and 12b are movably fixed to the support panel 17.

The first tooth 12g is provided on the tip portion 12d of one of the gear links 12a (the front side in FIG. 1 (A)), and the second tip portion 12d on the other end (the back side in FIG. 1 (A)). The teeth 12h are provided. The gear link 12b is provided with a first tooth 12g and a second tooth 12h. The first tooth 12g of the gear link 12a and the second tooth 12h of the gear link 12b mesh with each other, and the second tooth 12h of the gear link 12a and the first tooth 12g of the gear link 12b mesh with each other. In this way, the pair of gear links 12a and 12b are connected at the tip portion 12d and can move in conjunction with each other. The arm portion 12f extends from the tip portion 12d toward the shaft 12c.

When the key top 10 is not pressed (when not pressed), the two gear links 12a and 12b are assembled in an inverted V shape to support the key top 10. For example, when the key top 10 is pressed (when pressed) with an operator's finger or the like, the lower surface of the key top 10 presses down the dome rubber 15. As a result, the outer dome portion 15b of the dome rubber 15 buckles and deforms, the protrusion 15f of the inner dome portion 15d pushes down the membrane sheet 14, and the contact 14d is turned on. When the finger is released from the key top 10, the key top 10 is pushed upward by the upward elastic force of the outer dome portion 15b and the inner dome portion 15d. As the key top 10 is pressed, the rear ends of the gear links 12a and 12b slide in the horizontal direction (left-right direction). Further, the arm portion 12f falls downward. In this way, the gear links 12a and 12b guide the key top 10 in the vertical direction while keeping the key top 10 horizontal.

In FIG. 1A, the two gear links 12a and 12b are assembled in an inverted V shape to support the key top 10. However, the two gear links 12a and 12b may be assembled in a V shape.

Hereinafter, the relationship between the stroke S (pushing amount) and the load (pushing force) F of the key top 10 will be described. FIG. 3A is a diagram showing the load displacement characteristic of the dome rubber 15, and FIG. 3B is a diagram showing the load displacement characteristic of the dome rubber 150 according to the comparative example. In FIGS. 3A and 3B, the stroke S is on the horizontal axis and the load F is on the vertical axis, and the contact-on point a is also shown. F0 indicates the peak load, and F3 indicates the bottom load in which the load becomes the smallest after the peak load. S0 indicates a stroke corresponding to the peak load F0. S1 indicates the stroke when the contact 14d is turned on. S2 indicates a stroke end. S3 indicates a stroke corresponding to the bottom load F3. S4 indicates the stroke when the lower end of the protrusion 15f or the apex X of the inner dome portion 15m comes into contact with the membrane sheet 14.

In FIG. 3A, the dotted line indicates the load displacement characteristic of the outer dome portion 15b, the one-point chain line indicates the load displacement characteristic of the inner dome portion 15d, and the solid line indicates the load of the outer dome portion 15b and the inner dome portion 15d. The characteristics obtained by summing the displacement characteristics, that is, the load displacement characteristics of the dome rubber 15 are shown.

As shown in FIG. 3A, when the load F of the key top 10 increases from 0, the stroke S also increases from 0 accordingly. At this time, the outer dome portion 15b is elastically deformed, and the reaction force from the outer dome portion 15b acts on the key top 10. The load F increases until the load acting on the dome rubber 15 reaches the buckling load (that is, the peak load F0) of the dome rubber 15, and after that, the load F becomes gentle as the stroke S increases. Decreases to. By obtaining the peak load F0 by the buckling deformation of the dome rubber 15, the operator can obtain a click feeling peculiar to the keystroke operation.

In this case, the stroke S4 corresponds to the initial length P1 (see FIG. 2A) between the lower end of the protrusion 15f and the membrane sheet 14. This length P1 can be set by adjusting the length of the protrusion 15f. The stroke S4 can be changed by adjusting the length P1, and as a result, the stroke S1 of the key top 10 when the contact is turned on can be changed. That is, by adjusting the length P1, the stroke S1 of the key top 10 when the contact is turned on can be arbitrarily set.

In the present embodiment, the stroke S1 is set to a value larger than the stroke S0 at which the peak load F0 is generated and smaller than the stroke S3 corresponding to the bottom load F3 (for example, between S0 and S3). As a result, the contact 14d is turned on in the area where the load F is reduced after the operator feels a click, so that the operation feeling of the operator and the on operation of the contact 14d correspond well, and the operability of the key switch is improved. do.

In FIG. 3A, the stroke S0 and the stroke S4 overlap each other. That is, at the same time when the outer dome portion 15b reaches the buckling load (that is, the peak load F0), the lower end of the protrusion portion 15f comes into contact with the membrane sheet 14. However, as shown in FIG. 3B, the stroke S4 may be arranged slightly to the right of the stroke S0. In this case, the tip of the protrusion 15f comes into contact with the membrane sheet 14 after the outer dome portion 15b reaches the buckling load (that is, the peak load F0).

In the section between the stroke S0 corresponding to the peak load and the stroke S3 corresponding to the bottom load, that is, in the section where the load level decreases (hereinafter referred to as the click section), the load reduction amount of the outer dome portion 15b is that of the inner dome portion 15d. Slightly larger than the load increase. Therefore, in the click section, the load displacement characteristic (solid line) of the dome rubber 15 is gradually reduced.

By the way, in the click section, the load displacement characteristic (dashed line) of the inner dome portion 15d in FIG. 3 (A) gradually increases, while the load displacement characteristic (dashed line) of the inner dome portion 15 m in FIG. 3 (B) increases. It increases linearly. That is, in the click section, the load displacement characteristic (dotted chain line) of the inner dome portion 15d in FIG. 3 (A) has a higher load increase rate than the load displacement characteristic (dotted chain line) of the inner dome portion 15 m in FIG. 3 (B). It's down. This is because the inner dome portion 15d does not undergo buckling deformation, but deforms close to it, so that the load increase rate can be reduced for a certain section.

As described above, in the click section, the load displacement characteristic (dashed line) of the inner dome portion 15d in FIG. 3 (A) is larger than the load displacement characteristic (dashed line) of the inner dome portion 15 m in FIG. 3 (B). Since the rate is lowered, the stroke S3 corresponding to the bottom load in FIG. 3 (A) becomes larger than the stroke S3 in FIG. 3 (B), the click section can be lengthened, and a better operation feeling can be obtained.

4 (A) to 4 (D) are diagrams showing the transition state of the deformation of the dome rubber 15. 4 (E) to 4 (H) are diagrams showing the transition state of the deformation of the dome rubber 150.

FIG. 4A shows a state of the dome rubber 15 when the load F in FIG. 3A is 0 and the stroke S is 0. 4 (E) shows the state of the dome rubber 150 when the load F of FIG. 3 (B) is 0 and the stroke S is 0.

FIG. 4B shows the state of the dome rubber 15 when the load F in FIG. 3A is F0 and the strokes S are S0 and S4. In FIG. 4B, the tip of the protrusion 15f comes into contact with the membrane sheet 14 at the same time as or immediately after the outer dome portion 15b buckles and deforms. FIG. 4F shows the state of the dome rubber 150 when the load F in FIG. 3B is F0 and the stroke S is S4. In FIG. 4F, the apex X of the inner dome portion 15m comes into contact with the membrane sheet 14 immediately after the outer dome portion 15b buckles and deforms.

FIG. 4C shows the state of the dome rubber 15 when the stroke S in FIG. 3A is S1. The outer dome portion 15b continues to buckle and deform, and the load displacement characteristic of the outer dome portion 15b tends to decrease. The inner dome portion 15d presses the membrane sheet 14 and the contact 14d is turned on. Further, the bowl portion 15e of the inner dome portion 15d is deformed so that the inner dome portion 15d is accommodated in the recess 15g. The load displacement characteristic of the inner dome portion 15d tends to increase. The total characteristic of the load displacement characteristics of the outer dome portion 15b and the inner dome portion 15d tends to decrease.

FIG. 4 (G) shows the state of the dome rubber 150 when the stroke S in FIG. 3 (B) is S1. The outer dome portion 15b continues to buckle and deform, and the load displacement characteristic of the outer dome portion 15b tends to decrease. The inner dome portion 15m presses the membrane sheet 14 and the contact 14d is turned on. Further, the inner dome portion 15m is deformed so that the inner dome portion 15m is accommodated in the recess 15n. The load displacement characteristic of the inner dome portion 15 m tends to increase linearly. The total characteristic of the load displacement characteristics of the outer dome portion 15b and the inner dome portion 15m tends to decrease.

4 (D) shows the state of the dome rubber 15 when the load F in FIG. 3 (A) is F3 and the stroke S is S3. In FIG. 4D, the deformable state of the inner dome portion 15d is completed, and thereafter, the load displacement characteristic of the inner dome portion 15d tends to increase significantly. Further, the click section ends in FIG. 4 (D).

FIG. 4H shows the state of the dome rubber 150 when the load F in FIG. 3B is F3 and the stroke S is S3. In FIG. 4H, the deformable state of the inner dome portion 15 m is completed, and thereafter, the load displacement characteristic of the inner dome portion 15 m tends to increase significantly. Further, the click section ends in FIG. 4 (H).

FIG. 5A is a diagram showing a deformed state of the dome rubber 15 when the key top 10 is tilted. FIG. 5B is a diagram showing a deformed state of the dome rubber 150 when the key top 10 is tilted and the inner dome portion 15 m is buckled and deformed. FIG. 5C is a diagram showing a deformed state of the dome rubber 150 when the inner dome portion 15 m is inverted.

When the corner of the key top 10 is pressed and the key top 10 is tilted, the load is not evenly applied to the outer dome portion 15b and the inner dome portion 15m of the dome rubber 150. The portion 15 m may be buckled and deformed. Further, when the key top 10 is pushed beyond the stroke end, the inner dome portion 15 m of the dome rubber 150 may be inverted and may not return to the original shape as shown in FIG. 5 (C).

On the other hand, in the dome rubber 15, even when the corner of the key top 10 is pressed and the key top 10 is tilted, the protrusion 15f is provided in the center of the bowl portion 15e. As shown, the protrusion 15f becomes a fulcrum without buckling deformation and presses the contact point 14d. Therefore, the dome rubber 15 can press the contact point 14d without being affected by the inclination of the key top 10.

As described above, the dome rubber 15 has an outer dome portion 15b that applies a reaction force to the key top 10 in response to pressing of the key top 10, and a hemispherical bowl portion that is arranged inside the outer dome portion 15b. The inner dome portion 15d having a protrusion 15e protruding downward from the center of the bowl portion 15e and pressing the contact point 14d arranged below the key top 10 and integrally formed with the outer dome portion 15b. Be prepared. As a result, even when the corner of the key top 10 is pressed and the key top 10 is tilted, the protrusion 15f serves as a fulcrum and presses the contact 14d, so that the contact 14d is in the process of reducing the pressing load of the key top 10. Is turned on, and the operation feeling and the contact pressing operation can be well matched.

Although the examples of the present invention have been described in detail above, the present invention is not limited to the specific examples thereof, and various modifications and variations are made within the scope of the gist of the present invention described in the claims. It can be changed.

10 Key top 12a, 12b Gear link 14 Membrane sheet 14b, 14c Sheet board 14d Contact 15,150 Dome rubber 15b Outer dome part 15d Inner dome part 15e Bowl part 15f Protrusion part 100 Key switch device

Claims (4)

A first dome portion that applies a reaction force to the operating member in response to pressing of the operating member, and
A second dome portion having a hemispherical bowl portion arranged inside the first dome portion and a protrusion portion protruding downward from the center of the bowl portion and pressing a switch arranged below the operating member. And with
The first dome portion was buckled and deformed, and the second dome portion was not buckled and deformed.
A reaction force generating member, characterized in that the protrusion contacts the switch at the same time as the first dome portion undergoes the buckling deformation or immediately after the buckling deformation. Claim 1 is characterized in that the second dome portion has a load displacement characteristic in which the load increase rate is lower than the load displacement characteristic in which the pressing load of the operating member increases linearly according to the pressing amount of the operating member. The reaction force generating member described in 1. The first dome portion has a load displacement characteristic in which the pressing load of the operating member increases until the buckling deformation occurs in response to the pressing of the operating member, and the pressing load of the operating member decreases after the buckling deformation. death,
The second dome portion has a load displacement characteristic in which the pressing load of the operating member increases according to the pressing amount of the operating member.
When the pressing load of the operating member in the total load displacement characteristic of the first dome portion and the second dome portion is reduced in response to the pressing of the operating member, the protrusion turns on the switch. The reaction force generating member according to claim 1 or 2, characterized in that. The operating member to be pressed and
A switch located below the operating member and
A reaction force generating member provided between the operating member and the switch, the first dome portion that applies a reaction force to the operating member in response to pressing of the operating member, and the first dome portion. It has a hemispherical bowl portion arranged inside, and a second dome portion having a protrusion portion protruding downward from the center of the bowl portion and pressing a switch arranged below the operation member. The first dome portion is buckled and deformed, the second dome portion is not buckled and deformed, and the protrusion contacts the switch at the same time as the first dome portion is buckled or immediately after the buckling deformation. Reaction force generating member and
A key switch device characterized by being equipped with.

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