Rubber key

A rubber key comprising: a key top portion having a rectangular shape in planar view; a skirt portion formed along a perimeter of the key top portion; and a contact portion projecting within the skirt portion from the key top portion on a same side of the skirt portion in a convex state in a length direction of the key top portion, wherein a shortest distance from the contact portion to a virtual plane defined by a ring of an edge of the skirt portion is longer as measured at a portion closer to a center of the key top portion in the length direction than at a portion closer to an end of the key top portion in the length direction.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Japanese Patent Application No. JP 2011-288127, which was filed on Dec. 28, 2011, the disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The disclosure relates to a rubber key, of which a key top portion is rectangular-shaped in planar view.

BACKGROUND

As a rubber key, there has been conventionally known a two-step push button that operates accurately and has large tolerance to an oblique press. The two-step push button is provided with a metal cap, which is a kind of a rigid-body cap. Accordingly, when the button provided with the metal cap is pushed down, whichever area of the button provided with the metal cap is pushed, clear tactile sensation is presented, as the entire metal cap is depressed.

However, in such a rubber key whose key top portion is rectangular-shaped in planar view, if the key top portion is not a rigid body, the clear tactile sensation cannot be presented depending on the area pushed down, as the key top portion rectangular-shaped in planar view is deformed at the depression of the key top portion.

SUMMARY

The disclosure has been made to solve the above-described problem and has an object to provide a rubber key that presents clear tactile sensation to a user, whichever portion of the key top portion rectangular-shaped in planar view is pushed down.

To achieve the purpose of the disclosure, there is provided a rubber key comprising: a key top portion having a rectangular shape in planar view; a skirt portion formed along a perimeter of the key top portion; and a contact portion projecting within the skirt portion from the key top portion on a same side of the skirt portion in a convex state in a length direction of the key top portion, wherein a shortest distance from the contact portion to a virtual plane defined by a ring of an edge of the skirt portion is longer as measured at a portion closer to a center of the key top portion in the length direction than at a portion closer to an end of the key top portion in the length direction.

DETAILED DESCRIPTION

A detailed description of an exemplary embodiment of a rubber key embodying the disclosure will now be given referring to the accompanying drawings.

1. Configuration of the Embodiment

As shown inFIG. 1andFIG. 2, a rubber keyboard sheet101is provided with a plurality of rubber keys including a rubber key1according to the exemplary embodiment of the disclosure. The rubber key1according to the exemplary embodiment includes a key top portion2and a skirt portion3. The key top portion2has a rectangular shape in planar view. The skirt portion3is arranged along the perimeter of the key top portion2. Further, the skirt portion3is fixed on a substrate102, as shown inFIG. 3andFIG. 4.

Furthermore, as shown inFIG. 2throughFIG. 4, the rubber key1according to the embodiment is provided with a contact portion4and a support portion5. The contact portion4is composed of a first projecting portion4A, a second projecting portion4B, and a third projecting portion4C. The first projecting portion4A, the second projecting portion4B, and the third projecting portion4C project on the same side as the skirt portion3, within the skirt portion3from the undersurface of the key top portion2, and are formed each in a convex manner along a length direction D1(SeeFIG. 4) of the key top portion2. That is, the first projecting portion4A, the second projecting portion4B, and the third projecting portion4C are arranged in line along one long side (lower side inFIG. 2) of the key top portion2rectangular-shaped in planar view.

The first projecting portion4A and the third projecting portion4C are positioned on both sides of the key top portion2in the length direction D1, respectively. A projection height AH at the first projecting portion4A is even in the length direction D1of the key top portion2. A projection height CH at the third projecting portion4C is even in the length direction D1of the key top portion2. Further, the projection height AH at the first projecting portion4A is the same height as the projection height CH at the third projecting portion4C.

The second projecting portion4B is positioned at the center of the key top portion2in the length direction D1. A projection height BH at the second projecting portion4B is even in the length direction D1of the key top portion2. Further, a projection height BH at the second projecting portion4B is lower than the projection height AH at the first projecting portion4A or the projection height CH at the third projecting portion4C.

A projection height of the contact portion4composed of the first projecting portion4A, the second projecting portion4B, and the third projecting portion4C is thus made lower at a portion closer to a center line D2(seeFIG. 4) of the key top portion2with respect to the length direction D1than portions at both ends of the key top portion2in the length direction D1.

Incidentally, carbon is printed on each tip of the first projecting portion4A, the second projecting portion4B and the third projecting portion4composing the contact portion4C, to form a conductive portion.

The support portion5is formed in a convex shape along the length direction D1of the key top portion2, protruding from the key top portion2inside the skirt portion3. The support portion5is parallel with the first projecting portion4A, the second projecting portion4B, and the third projecting portion4C composing the contact portion4. That is, the support portion5is formed in a linear shape along the other long side (upper side inFIG. 2) of the key top portion2having the rectangular shape in planar view.

Furthermore, as shown inFIG. 2, the support portion5is arranged side by side with the first projecting portion4A, the second projecting portion4B and the third projecting portion4C composing the contact portion4with respect to a breadth direction D3(seeFIG. 3) of the key top portion2.

A projection height H5(seeFIG. 3) of the support portion5is even in the length direction D1of the key top portion2. The projection height H5of the support portion5is higher than any of the projection heights AH, BH, CH at the first projecting portion4A, the second projecting portion4B, and the third projecting portion4C composing the contact portion4.

The undersurface of the key top portion2is substantially flat. Accordingly, the shortest distance (interval) from the undersurface of the key top portion2to the substrate102is substantially the same at any location in the undersurface of the key top portion2. Furthermore, with respect to the shortest distance (interval) from the contact portion4to the substrate102, the shortest distance measured at the second projecting portion4B is longer than the shortest distance measured at the first projecting portion4A or the third projecting portion4C.

Here, as shown inFIG. 3orFIG. 4, a ring of a lower edge3A of the skirt portion3defines a virtual plane F which overlaps the surface of the substrate102. Accordingly, with respect to the shortest distance (interval) from the contact portion4to the virtual plane F, the shortest distance (interval) is longer as measured at the second projecting portion4B than at the first projecting portion4A or the third projecting portion4C. That is, a shortest distance of a distance BL at the second projecting portion4B is longer than a shortest distance of a distance AL at the first projecting portion4A or a shortest distance of a distance CL at the third projecting portion4C. The shortest distance of the distance AL at the first projecting portion4A is the same as the shortest distance of the distance CL at the third projecting portion4C. Accordingly, the shortest distance (interval) from the contact portion4to the virtual plane F is longer at a portion closer to the center line D2of the key top portion2with respect to the length direction D1than at portions on both ends in the length direction D1of the key top portion2.

Further, as shown inFIG. 3, the distance (interval) from the contact portion4to the virtual plane F is configured to gradually increase as measured from a side thereof closer to the support portion5to a side farther away from the support portion5in the breadth direction D3of the key top portion2. That is, the distance BL at the second projecting portion4B and the distance CL at the third projecting portion4C are configured to gradually increase as measured toward a side thereof farther away from the support portion5with respect to the breadth direction D3of the key top portion2. The same can be applied to the distance AL at the first projecting portion4A whose shortest distance is the same distance (interval) as the shortest distance CL at the third projecting portion4C.

Further, as shown inFIG. 3, the top surface of the key top portion2is configured to slope gradually upward from the side where the support portion5is provided toward the side where the contact portion4is provided with respect to the breadth direction D3of the key top portion2.

Incidentally, the rubber key1is made of a single rubber except the portion of carbon print, and the difference in thickness makes the difference in stiffness.

2. Operation of the Disclosure

In the rubber key1according to the embodiment, when the key top portion2is pushed down, the support portion5first makes contact with the substrate102. Thereafter, the first projecting portion4A, the second projecting portion4B, and the third projecting portion4C composing the contact portion4move using the point where the support portion5has made contact with the substrate102as the point of support for the movement, to make contact with the substrate102. That is, the rubber key1according to the embodiment operates like a so-called piano-style key.

As shown inFIG. 4, when the key top portion2of the rubber key1according to the embodiment is pushed down while the skirt portion3is fixed on the substrate102, the contact portion4projecting from the key top portion2, in other words, the first projecting portion4A, the second projecting portion4B, and the third projecting portion4C move to make contact with the substrate102.

Here, the projection height of the contact portion4composed of the first projecting portion4A, the second projecting portion4B, and the third projecting portion4C is formed to be lower at the portion closer to the center line D2of the key top portion2having the rectangular shape in planar view with respect to the length direction D1than at portions on the both ends of the key top portion2rectangular-shaped in planar view in the length direction D1. That is, the height of the contact portion4is formed to vary with location in one rubber key1.

Accordingly, the shortest distance (interval) from the contact portion4to the virtual plane F defined by the ring of the edge3A of the skirt portion3is longer as measured at the portion closer to the center line D2of the key top portion2in the length direction D1than at the portions on both ends in the length direction D1of the key top portion2. That is, in this case, the distance that the contact portion4including the first projecting portion4A, the second projecting portion4B and the third projecting portion4C has to cover to make contact with the substrate102is longer at the portion closer to the center line D2of the key top portion2having the rectangular shape in planar view in the length direction D1than at the portions on both ends of the key top portion2having the rectangular shape in planar view in the length direction D1.

As a result, the skirt portion3at the perimeter of the key top portion2having the rectangular shape in planar view in the length direction D1buckles, not only in a case a user presses an end portion on the top surface thereof the key top portion2having the rectangular shape in planar view in the length direction D1, but also in a case the user presses the center of the key top portion2having the rectangular shape in planar view in the length direction D1, as shown inFIG. 4, so that the key top portion2having the rectangular shape in planar view presents an excellent tactile sensation to the user.

In other words, in the rubber key1according to the embodiment, the key top portion2having the rectangular shape in planar view can present an excellent tactile sensation to the user whichever area thereof is pressed.

3. Other

It is to be noted that the disclosure is not restricted to aspects according to the present embodiment and that various changes and modification may be made without departing from the gist of the disclosure.

[3-1. First Alternative Configuration of Contact Portion]

For instance, the contact portion4may be composed of four or more projecting portions in such a manner that the projection height of the contact portion4is lower at a portion closer to the center line D2of the key top portion2having the rectangular shape in planar view in the length direction D1, than at portions closer to both ends of the key top portion2having the rectangular shape in planar view in the length direction D1. Also in this case, the shortest distance (interval) from the contact portion4to the virtual plane F defined by the ring of the edge3A of the skirt portion3is longer as measured at the portion closer to the center line D2of the key top portion2with respect to the length direction D1than at the portions closer to both ends of the key top portion2in the length direction D1.

[3-2. Second Alternative Configuration of Contact Portion]

Further, the contact portion4may be composed of one projecting portion, in such a manner that the projection height of the contact portion4becomes lower toward the center line D2of the key top portion2having the rectangular shape in planar view in the length direction D1, from both ends of the key top portion2having the rectangular shape in planar view in the length direction D1. Also in this case, the shortest distance (interval) from the contact portion4to the virtual plane F defined by the ring of the edge3A of the skirt portion3becomes longer toward the center line D2of the key top portion2in the length direction D1from both ends of the key top portion2in the length direction D1.

[3-3. Configuration of Support Portion]

The support portion5may be configured to always have contact with the substrate102, regardless of the state of the key top portion2: being pressed or not pressed.

Further, the tactile sensation of the rubber key1according to the embodiment can be made to be the same as the tactile sensation of any other rubber key in the rubber keyboard sheet101. Hereinafter, there is discussed a case where the tactile sensation of the rubber key1according to the embodiment is made to be the same as the tactile sensation of a rubber key11shown inFIG. 1throughFIG. 3.

The rubber key11shown inFIG. 1throughFIG. 3is a rubber key adjacent to the rubber key1according to the embodiment, and includes a key top portion12and a skirt portion13. The key top portion12has a substantially square shape in planar view. The skirt portion13is arranged along the perimeter of the key top portion12. Further, the skirt portion13is fixed on the substrate102, as shown inFIG. 3.

Further, as shown inFIG. 2andFIG. 3, the rubber key11is provided with a contact portion14and a support portion15. The contact portion14projects on the same side of the skirt portion13, within the skirt portion13from the undersurface of the key top portion12, in a convex and linear shape along the lower side (lower portion inFIG. 2) of the key top portion12. A projection height14H of the contact portion14is even in a direction along the lower side (lower portion inFIG. 2) of key top portion12. Incidentally, carbon is printed on the tip of the contact portion14to form a conductive portion.

The support portion15protrudes within the skirt portion13from the undersurface of the key top portion12, in a convex and linear shape along the upper side (upper portion inFIG. 2) of key top portion12. That is, the support portion15is arranged parallel to the contact portion14. A projection height15H of the support portion15is even in a direction along the upper side (upper portion inFIG. 2) of the key top portion12. The projection height15H of the support portion15is higher than the projection height14H of the contact portion14.

Accordingly, as shown inFIG. 2, the support portion15is arranged side by side with the contact portion14with respect to the breadth direction D3(seeFIG. 3) of the key top portion12.

Further, as shown inFIG. 3, the above-described virtual plane F also serves as a virtual plane defined by a ring of the edge13A of the skirt portion13. An interval which is a distance14L from the contact portion14to the virtual plane F is configured to gradually increase as measured from a side thereof closer to the support portion15to a side farther away from the support portion15of the key top portion12in the breadth direction D3.

Further, as shown inFIG. 3, the top surface of the key top portion12is configured to slope gradually upward from the side where the support portion15is provided toward the side where the contact portion14is provided with respect to the breadth direction D3in the key top portion12.

In the rubber key11, when the key top portion12is pushed down, the support portion15first makes contact with the substrate102. Thereafter, the contact portion14moves using the point where the support portion15has made contact with the substrate102as the point of support for movement, to make contact with the substrate102. That is, the rubber key11operates like a so-called piano-style key, as well as the rubber key1according to the embodiment.

Then, in order to make the tactile sensation at the rubber key1according to the embodiment to be the same as the tactile sensation at the rubber key11, the projection height AH at the first projecting portion4A and the projection height CH at the third projecting portion4C in the rubber key1according to the embodiment are configured to be the same height as the projection height14H of the contact portion14in the rubber key11. That is, in the rubber key1according to this embodiment, the shortest of the distance AL at the first projecting portion4A and the shortest of the distance CL at the third projecting portion4C are configured to be the same distance (interval) as the shortest of the distance14L of the contact portion14in the rubber key11.

That is, the projection heights AH, CH at the first projecting portion4A and the third projecting portion4C in the rubber key1according to the embodiment on both sides of the key top portion2having the rectangular shape in planar view in the length direction D1may be set the same height as the projection height14H of the contact portion14in the rubber key11. That is, in the rubber key1according to this embodiment, the shortest distance of the distances AL, CL of the first projecting portion4A and the third projecting portion4C positioned on both ends of the key top portion2rectangular-shaped in planer view in the length direction D1can be set in the same distance (interval) as the shortest of the distance14L of the contact portion14in the rubber key11.

However, there is a requirement that the distance from the undersurface of the key top portion2of the rubber key1according to the embodiment to the substrate102is equal to the distance from the undersurface of the key top portion12of the rubber key11to the substrate102, and that at the same time the projection height5H of the support portion5of the rubber key1according to the embodiment is equal to the projection height15H of the support portion15of the rubber key11.

Incidentally, the rubber key11is made of the same single rubber except the portion of carbon print, as in the rubber key1according to the embodiment, and the difference in thickness makes the difference in stiffness.

[3-4. Omission of Support Portion]

Further, in the rubber key1according to the embodiment, even in a configuration not using the so-called piano-style key; namely, even in a configuration in which the support portion5is omitted, the key top portion2having the rectangular shape in planar view can present an excellent tactile sensation to a user whichever area thereof is pressed.

While presently exemplary embodiments have been shown and described, it is to be understood that this disclosure is for the purpose of illustration and that various changes and modifications may be made without departing from the scope of the disclosure as set forth in the appended claims.