Key input circuit and portable terminal input device

• US 6,639,159 B2
• Filed: 12/13/2002
• Issued: 10/28/2003
• Est. Priority Date: 12/14/2001
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Anzai, Takeshi
• Primary Examiner(s): SCOTT, JAMES R
• Application Number:
  US10/319,136
• Publication Number:
  US 20030116419A1
• Time in Patent Office: 319 Days
• Field of Search: 200/1.B, 200/5.A, 200/512-517, 200/275, 200/406
• US Class Current: 200/1.00B
• CPC Class Codes: H01H 13/48 using buckling of disc springs
• CPC Class Codes: H01H 13/7006 comprising a separate movable contact element for each switch site, all other elements being integrated in layers
• CPC Class Codes: H01H 13/807 characterised by the spatial arrangement of the contact sites, e.g. superimposed sites
• CPC Class Codes: H01H 2203/02 Interspersed fingers
• CPC Class Codes: H01H 2203/038 to be bridged by a dome shaped contact
• CPC Class Codes: H01H 2225/002 superimposed
• CPC Class Codes: H01H 2225/01 Different switch sites under one actuator in same plane
• CPC Class Codes: H01H 2225/018 Consecutive operations

Abstract

A key input device for portable terminals and the like, having a reduced sized and improved key input operation. The device has a wiring substrate, multiple keys on the substrate, with each key having three-dimensional displacement surfaces that are displacable in a linked fashion relative to one another. The displacement surfaces have a preceding displacement surface and a succeeding displacement surface corresponding respectively to a preceding and a succeeding key displacement. A first switching operation occurs when a first key part of a first key and first substrate part of the wiring substrate are brought into mechanical contact with each other on the basis of displacement of the preceding displacement surface. A second switching operation results when a second key part of a second key and a second substrate part of the wiring surface are contacted on the basis of displacement of the succeeding displacement surface.

Claims

1. A key input device comprising:

a wiring substrate; and

a plurality of keys disposed on the wiring substrate and each having three-dimensional displacement surfaces capable of being displaced in a linked fashion relative to one another;

the three-dimensional displacement surfaces being;

a preceding displacement surface capable of undergoing a first displacement preceding in time; and

a succeeding displacement surface capable of undergoing a second displacement subsequent in time to the first displacement of the preceding displacement surface;

the succeeding displacement surface being capable of undergoing the second displacement by a displacing force of the first displacement;

the plurality of keys each having;

a first key forming the preceding displacement surface; and

a second key having the succeeding displacement surface;

a first switching operation being brought about when a first key part of the first key and a first substrate part of the wiring substrate are brought into mechanical contact with each other on the basis of displacement of the preceding displacement surface;

a second switching operation being brought about when a second key part of the second key and a second substrate part of the wiring substrate are brought into mechanical contact with each other on the basis of displacement of the succeeding displacement surface;

each of the keys executing the first and second switching operations by movement of its part perpendicular to the substrate surface of the wiring substrate; and

the preceding and succeeding displacement surfaces each forming, before displacement, a convex surface in a direction opposite to the direction of the movement.

2. The key input device according to claim 1, wherein the first switching operation is brought about when the first key part and the first substrate part of the wiring substrate are brought into contact via the second key part with each other.

3. The key input device according to claim 2, wherein the first key, the wiring substrate and the second key together form a first closed space, and the second key and the wiring substrate together form a second closed space.

4. The key input device according to one of claims 2 and 3, wherein:

the wiring substrate has;

a first electrode fixedly bonded to the first key;

a second electrode fixedly bonded to the second key; and

a third electrode facing the second closed space;

the first substrate part corresponding to the second electrode;

the second substrate part corresponding to the third electrode.

5. The key input device according to claim 4, wherein:

the first electrode forms a first closed ring, the second electrode forms a second closed ring, the first key has its entire circumference bonded to the first ring, the second key has its entire circumference bonded to the second ring, the first ring is electrically connected to GND (ground), the second ring is connected to a first input port of a CPU (central processing unit), and the third electrode is connected to a second input port of the CPU.

6. The key input device according to claim 4, wherein the first key has an electrically conductive first inner surface, the first inner surface is electrically connected to the first electrode, the second key has an electrically conductive second inner surface, the second inner surface is electrically connected to the second electrode.

7. The key input device according to claim 6, wherein:

the first key has;

a first body part made of a resin; and

a first electrically conductive film formed on the inner side of the first body part;

the first inner surface corresponding to the inner surface of the first electrically conductive film; and

the second key has;

a second body part made of a resin; and

a second electrically conductive film formed on the inner side of the second body part;

the second inner surface corresponding to the inner surface of the second electrically conductive film.

8. The key input device according to claim 1, wherein the first and second keys are made of an electrically conductive metal.

9. The key input device according to one of claims 1, 2, 3 and 8, wherein:

the wiring substrate has a plurality of lead lines formed in its inside;

either one of the first to third electrodes being electrically connected via a connecting lead extending perpendicular to the wiring substrate to the wiring.

10. The key input device according to one of claims 1, 2, 3, and 8, wherein:

the first and second keys are both semi-spherical shell-like in form.

11. The key input device according to one of claims 1, 2, 3 and 8, wherein:

the first and second keys are both frust-conical in form.

12. The key input device according to claim 1, wherein:

the preceding and succeeding displacement surfaces form a continuous displacement surface, and the continuous displacement surface and the substrate surface of the wiring substrate form a single closed space.

13. The key input device according to claim 1, wherein:

the wiring substrate has;

a first lead line having a first disconnected part; and

a second lead line having a second disconnected part;

the first and second key parts are both electrically conductive;

the first switching operation is brought about when the first key part is electrically coupled to the first disconnected part; and

the second switching operation is brought about when the second key part is electrically coupled to the second disconnected part.

14. The key input device according to claim 13, wherein:

the first lead line has one side electrically connected to the ground and the other side connected to the first input port of the CPU; and

the second lead line has one side electrically connected to the ground and the other side connected to the second input port of the CPU.

15. The key input device according to claim 14, wherein:

the first key has;

a first frust-conical form part having a larger outer diameter; and

a first disk-like part integral with the first frust-conical form part and substantially parallel to the wiring substrate surface;

the second key has;

a second frust-conical form part having a smaller outer diameter; and

a second disk-like part integral with the second frust-conical form part and substantially parallel to the wiring substrate surface;

the first disk-like part is integral with the second frust-conical form part; and

the first key part is formed on the first disk-like part, and the second key part is formed on the second disk-like part.

16. The key input device according to claim 14, wherein:

the first key has;

a first partly spherical shell-like part having a larger outer diameter; and

a second partly spherical shell-like part having a smaller outer diameter;

the first partly.spherical shell-like part being continuous to and integral with the second partly spherical shell-like part.

17. The key input device according to one of claims 12 to 16, wherein:

the first lead line has a first one side disconnected part formed in a first one side concave part and also has a first other side disconnected part formed in a first other side concave part, the first one side disconnected part having a portion extending in the first other side concave part, the first other side disconnected part having a portion extending in the first one side concave part; and

the second lead line has a second one side disconnected part formed n a second one side concave part and also has a second other side disconnected part formed in a second other side concave part, the second one side disconnected part having a portion extending in the second one side disconnected part, the second other side disconnected part having a portion extending in the second one side concave part.

18. The key input device according to one of claims 13, 14, 15 and 16, wherein:

the surfaces of the first and second key parts are both smoothly curved surfaces.

19. The key input device according to claim 1, wherein:

the first switching operation is brought about when the first key part and the first substrate part of the wiring substrate are brought into contact via the second key part to each other, the first key, the wiring substrate and the second key together form a first closed space, the second key and the wiring substrate together form a second closed space;

the wiring substrate has;

a first electrode fixedly bonded to the first key; and

a second electrode fixedly bonded to the second key;

the first substrate part corresponds to the first electrode;

the second substrate part corresponds to the third electrode; and

the first electrode forms a first ring, the second electrode forms a second ring, the first key has the entire circumference bonded to the first ring, the second key has the entire circumference bonded to the second ring, the first ring is electrically connected to the GND, the second ring is connected to a first input port of a CPU, and the third electrode is connected to a second input port of the CPU.

20. The key input device according to claim 1, wherein:

the preceding and succeeding displacement surfaces together form an integral continuous displacement surface, the continuous displacement surface and the substrate surface of the wiring substrate together form a single closed space;

the wiring substrate has;

a first lead line having a first disconnected part; and

a second lead line having a second disconnected part;

the first and second key parts are both electrically conductive;

the first switching operation is brought about when the first key part is electrically coupled to the first disconnected part, the second switching operation is brought about when the second key part is electrically coupled to the second disconnected part; and

the first lead line has one side electrically connected to the GND and the other side connected to a first input port of a CPU, the second lead line has one side electrically connected to the GND and the other side connected to a second input port of the CPU; and

the first key has a first inner surface, which is electrically conductive and is electrically connected to the first electrode, the second key has a second inner surface, which is electrically conductive and is electrically connected to the second electrode.

21. The key input device according to claim 20, wherein:

the first key has;

a first frust-conical form part having a larger outer diameter; and

a first disk-like part integral with the first frust-conical form part and substantially parallel to the wiring substrate surface;

the second key has;

a second frust-conical form part having a smaller outer diameter; and

a second disk-like part integral with the second frust-conical form part and substantially parallel to the wiring substrate surface;

the first disk-like part being continuous to and integral with the second frust-conical form part;

the first key part is formed on the first disk-like part, the second key part being formed on the second disk-like part.

22. The key input device according to claim 20, wherein:

the first key has;

a first partly spherical shell-like part having a later outer diameter; and

a second partly spherical shell-like part having a smaller outer diameter; and

the first partly spherical shell-like part is continuous to and integral with the second partly spherical shell-like part.

23. An input device for a portable terminal comprising:

a casing;

two CPU ports of a CPU, the CPU ports being fixedly disposed inside the casing;

a key group constituted by a plurality of keys as elements movably supported on the casing and forming the outer surface thereof; and

a wiring substrate having a plurality of electrodes supported in the casing such as to be capable of being connected to the keys;

the keys are each capable of undergoing reciprocal movement having components perpendicular to the outer surface;

the keys are each capable of being brought into contact with the electrodes by two-step contact in a forward stroke in the perpendicular direction;

a second step contact of the two-step contact is a mechanically essential condition of a first step contact of the two-step contact; and

the two-step contact switches the voltage states of the two input ports of the CPU in a linked fashion.

24. The input device for a portable terminal according to claim 23, wherein:

the keys each form a three-dimensional displacement surface capable of being displaced in a linked fashion;

the three-dimensional displacement surface has;

a preceding displacement surface capable of undergoing a first displacement preceding in time; and

a succeeding displacement surface capable of undergoing a second displacement succeeding the first displacement of the preceding displacement surface and in a fashion mechanically linked to the first displacement;

the second displacement of the succeeding displacement surface is generated by a displacing force of the first displacement; and

the keys each have;

a first key forming the preceding displacement surface; and

a second key forming the succeeding displacement surface;

the first step contact being mechanical contact brought about between a first key part of the first key and a first electrode among the plurality of electrodes on the basis of displacement of the preceding displacement surface;

the second step contact being mechanical contact brought about between a second key part of the second key and a second electrode among the plurality of electrodes on the basis of displacement of the succeeding displacement surface.

25. The input device for a portable terminal according to one of claims 23 and 24, wherein:

the first step contact corresponds to numeral “

j”

of a numeral key, and the second step contact corresponds to numeral “

j+1”

of the numeral key.

26. The input device for a portable terminal according to claim 25, wherein:

if the minimum value of the numeral “

j”

is “

0”

, the second step contact corresponds to an odd numeral of the numeral key.

27. The input device for a portable terminal according to one of claims 23 and 24, wherein:

the keys each have;

a first function key;

a second function key;

shallow push-down of the first function key causes start of a function f1;

shallow push-down of the second function key causes start of a function f2; and

deep push-down of the first function key causes start of a function f3 corresponding to the shallow push-down of the first function key and the shallow push-down of the second function key.