Switch contact structure

Details Switch contact structure Switch contact structure

2001-06-28

2003-06-03

Friedhofer, Michael (Department: 2832)

Electricity: circuit makers and breakers

Snap

Double snap

C200S516000, C200S512000, C200S0050EA

Reexamination Certificate

active

06573467

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a contact structure of a switch for a compact electronic device used for a numeric keypad of a mobile telephone or the like, and more particularly, to a contact structure of a switch that is reduced in size and weight to the utmost and in which resources are saved to the utmost.
BACKGROUND ART
In a numeric keypad for a data inputting apparatus of OA equipment and AV equipment, a facsimile machine, and a telephone terminal apparatus including a mobile telephone as shown in
FIG. 9
, a keyboard switch using a substantially pan-like diaphragm made of metal or conductive material such as conductive plastic having spring characteristics is conventionally employed.
The keyboard switch will be explained while taking a mobile telephone shown in
FIG. 9
as an example. A printed board
26
shown with a broken line is disposed in a case
27
. Circle contacts
21
that are first contacts shown also with broken lines and diaphragms
25
shown with broken lines for bringing C-contacts or annular contacts that are second contacts into conduction are disposed in the printed board
26
.
The case
27
is provided with keys
20
that can be pushed down, and if the key
20
is pushed down, a central portion of the diaphragm
25
is pushed and the circle contact
21
and the C-contact or annular contact are brought into conduction.
Details of a contact structure for a keyboard switch is disclosed in Japanese Patent Application Laid-open No. 5-74267. As shown in
FIG. 10
for example, the circle contact
21
that is the first contact is disposed on the printed board
26
, the circle contact
21
is surrounded by the C-contact
22
that is the second contact, the diaphragm
25
is placed on the C-contact
22
and fixed onto the printed board
26
through a single-sided adhesive sheet
28
.
Then, as shown in
FIG. 11
, the central portion
25
a
of the diaphragm of the conductor is pushed and deformed by the key
20
, and the circle contact
21
that is the first contact and the C-contact
22
that is the second contact are brought into conduction.
A shape of the contact may be annular instead of C-shape as disclosed in Japanese Patent Application Laid-open No. 3-230431.
FIG. 12
schematically shows the circle contact
21
and the annular contact
22
of the printed board
26
accommodated in the case
27
of a mobile telephone shown in FIG.
9
.
According to these conventional contact structures, however, the central portion of the conductive diaphragm is pushed and deformed to bring the central circle contact and the C-contact into conduction, and the conduction between the contacts is cut off by a restoring force of the diaphragm.
Therefore, it is necessary to make an outer shape of the diaphragm large in some degrees. Even if the central circle contact is made small, a size of the C-contact corresponds to that of an outer periphery of the diaphragm.
In recent compact electronic device such as a mobile telephone, a weight of an entire device is evaluated as an important index for carrying performance. Therefore, every part need be reduced in weight to achieve the weight reduction in gram.
Thus, size and weight reducing utmost method is required for a contact using metal material. A problem is how to reduce the weight while enhancing or maintaining the performance. On the other hand, it has become widely and increasingly valued in effectively using resources or recycle, and it is required to save metal such as gold that is rare metal.
It is an object of the present invention to provide a contact structure of a switch for a compact electronic device used for a numeric keypad of a mobile telephone or the like that can be reduced in size and weight to the utmost and in which resources can be saved to the utmost.
DISCLOSURE OF THE INVENTION
To achieve the above object, according to the present invention, there is provided a contact structure of a switch comprising a first contact, and one or more second contacts surrounding the first contact, wherein the second contacts are provided with one or more band-like contacts extending to the opposite side from the first contact.
The band-like contacts may extend radially with respect to a center of the first contact, or the band-like contacts may extend into fan-like shape with respect to a center of the first contact.
Since the one or more second contacts surrounding the first contact are provided with the one or more band-like contacts extending to the opposite side from the first contact, there is a merit that an area of the metal pattern portion of the second contact can be made smaller as compared with the prior art.
Further, if the band-like contacts extend radially with respect to a center of the first contact, there is a merit that a larger number of band-like contacts having smaller width can be disposed.
Further, if the band-like contacts extend into fan-like shape with respect to a center of the first contact, there is a merit that the area of the metal pattern portion of the second contact becomes wider as separating from the center of the first contact.
Further, the present invention provides a contact structure of a switch comprising a first contact, one or more second contacts surrounding the first contact, and a pan-like diaphragm comprising a conductor, wherein the second contacts are provided with one or more band-like contacts extending to the opposite side from the first contact, an outer periphery of the pan-like diaphragm is placed on the band-like contacts extending from the second contacts and brought into conduction with the band-like contacts, a center of the pan-like diaphragm is pushed down and bent, the center of the pan-like diaphragm is brought into contact with the first contact and into conduction therewith, thereby bringing the switch into conduction.
The band-like contacts may extend radially with respect to a center of the first contact, or the band-like contacts may extend into fan-like shape with respect to a center of the first contact.
The switch portion comprises the first contact, the one or more second contacts surrounding the first contact, and the pan-like diaphragm comprising a conductor, the second contacts are provided with one or more band-like contacts extending to the opposite side from the first contact, an outer periphery of the pan-like diaphragm is placed on the band-like contacts extending from the second contacts and brought into conduction with the band-like contacts, a center of the pan-like diaphragm is pushed down and bent, the center of the pan-like diaphragm is brought into contact with the first contact and into conduction therewith, thereby bringing the switch into conduction. Therefore, there is a merit that switch can be brought into conduction even if the second contacts do not correspond to the entire portion of the outer periphery of the diaphragm.
Further, if the band-like contacts extend radially with respect to a center of the first contact, there is a merit that a larger number of band-like contacts having smaller width can be disposed.
Further, if the band-like contacts extends into fan-like shape with respect to a center of the first contact, there is a merit that the area of the metal pattern portion of the second contact becomes wider as separating from the center of the first contact.


REFERENCES:
patent: 5268542 (1993-12-01), Voll
patent: 5313027 (1994-05-01), Inoue et al.
patent: 5510584 (1996-04-01), Norris
patent: 5924555 (1999-07-01), Sadamori et al.
patent: 56-134641 (1981-10-01), None
patent: 2-126524 (1990-05-01), None
patent: 3-230431 (1991-10-01), None
patent: 4-31225 (1992-03-01), None
patent: 4-68311 (1992-06-01), None
patent: 5-74267 (1993-03-01), None
patent: 8-241647 (1996-09-01), None

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