Title: Movable contact unit, panel switch using the same and electronic equipment having the panel switch
Abstract: A movable contact unit including movable contacts localized in respective through holes of a base sheet formed from a flexible insulation substrate; a cover sheet formed from a flexible insulation substrate bonded on upper surface of the base sheet to hold respective movable contacts in the through holes; a weak adhesive layer applied on bottom surface of the base sheet of the movable contact unit except the through holes; and the movable contact unit bonded on stationary contact substrate having corresponding stationary contacts to respective movable contacts using the weak adhesive layer.
Patent Number: 6,906,275 Issued on 06/14/2005 to Koyama, et al.
| Inventors:
|
Koyama; Hiromichi (Katsuta-gun, JP);
Sako; Koji (Katsuta-gun, JP)
|
| Assignee:
|
Matsushita Electric Industrial Co., Ltd. (JP)
|
| Appl. No.:
|
292821 |
| Filed:
|
November 13, 2002 |
Foreign Application Priority Data
| Nov 15, 2001[JP] | 2001-349890 |
| Current U.S. Class: |
200/516; 200/406; 200/512 |
| Intern'l Class: |
H01H 003/00 |
| Field of Search: |
200/512-517,406,5A
29/622
|
References Cited [Referenced By]
U.S. Patent Documents
| 5225818 | Jul., 1993 | Lee et al.
| |
| 5845766 | Dec., 1998 | Sako et al.
| |
| 5975711 | Nov., 1999 | Parker et al.
| |
| 5986228 | Nov., 1999 | Okamoto et al.
| |
| 6417467 | Jul., 2002 | Yamagata.
| |
| 6548778 | Apr., 2003 | Takahashi.
| |
| 6604278 | Aug., 2003 | Sera et al.
| |
| 6634090 | Oct., 2003 | Koyama et al.
| |
| 6730869 | May., 2004 | Teruyama et al.
| |
| 6768074 | Jul., 2004 | Iwama.
| |
Primary Examiner: Friedhofer; Michael A.
Attorney, Agent or Firm: Parkhurst & Wendel, L.L.P.
Claims
1. A movable contact unit comprising:
a base sheet comprising a first flexible insulation substrate having a plurality
of through holes in predetermined positions;
a plurality of movable contacts located for moving vertically in the through
holes of said base sheet;
a cover sheet comprising a second flexible insulation substrate having an adhesive
coating on a bottom surface thereof, and bonded to an upper surface of said base
sheet said adhesive coating to hold said movable contacts in predetermined positions
in the through holes of said base sheet; and
a weak, easily peelable adhesive layer on a bottom surface of said base sheet
except the through holes,
wherein
said movable contact unit is for adhering to a stationary contact substrate,
and
said weak, easily peelable adhesive layer has an adhesion strength weak enough
to avoid damaging a stationary contact substrate upon separation of the contact
unit therefrom after being adhered thereto.
2. The movable contact unit of claim 1, wherein
each of said movable contacts comprises a resilient thin metal sheet having a
dome shape, and
a convex upper surface of each of said movable contacts is bonded to said adhesive
coating on the bottom surface of said cover sheet to hold said movable contacts
in the through holes of said base sheet.
3. The movable contact unit of claim 2, wherein said weak, easily peelable adhesive
layer the bottom surface of said base sheet comprises a gap around each movable contact.
4. A panel switch, comprising:
a movable contact unit comprising:
a base sheet comprising a first flexible insulation substrate having a plurality
of through holes in predetermined positions;
a plurality of movable contacts placed located for moving vertically in the through
holes of said base sheet;
a cover sheet comprising a second flexible insulation substrate and having an
adhesive coating on a bottom surface thereof, and bonded to an upper surface of
said base sheet said adhesive coating to hold said movable contacts in predetermined
positions in through holes of said base sheet; and
a weak easily peelable adhesive layer on a bottom surface of said base sheet
except the through holes; and
a stationary contact substrate comprising:
a rigid insulation board;
stationary contacts corresponding to said movable contacts and mounted on said
insulation board; and
said movable contact unit and said insulation board bonded together by said weak
adhesive layer on the bottom surface of said base sheet of said movable contact
unit, wherein
said weak, easily peelable adhesive layer has an adhesion strength weak enough
to avoid damaging said insulation board upon separation of the movable contact
unit therefrom after being adhered thereto.
5. An electronic equipment, comprising:
a bottom housing and an upper housing, said upper housing having an operation
section comprising a plurality of operation buttons on a surface of the upper housing,
each of said operation buttons operatively connected to a panel switch located
at a bottom side thereof each panel switch comprising:
a movable contact unit comprising:
a base sheet comprising a first flexible insulation substrate having a plurality
of through holes in predetermined positions;
a plurality of movable contacts located for moving vertically in the through
holes of said base sheet;
a cover sheet comprising a second flexible insulation substrate and having an
adhesive coating on a bottom surface thereof, and bonded to an upper surface of
said base sheet by said adhesive coating to hold said movable contacts in predetermined
positions in through holes of said base sheet; and
a weak easily peelable adhesive layer on a bottom surface of said base sheet
except the through holes;
a stationary contact substrate comprising:
a rigid insulation board;
stationary contacts corresponding to each of said movable contacts and mounted
on said insulation board, wherein
said movable contact unit and said stationary contact substrate are bonded together
by said weak, easily peelable adhesive layer on the bottom surface of said base
sheet of said movable contact unit, so that said stationary contact substrate is
attached to the bottom housing, and
said weak, easily peelable adhesive layer has an adhesion strength weak enough
to avoid damaging said insulation board upon separation of the movable contact
unit therefrom after being adhered thereto.
6. The electronic equipment of claim 5, further comprising:
a display section having an LCD unit for providing a display visible from an
upper side of the upper housing;
a light guide secured on a bottom surface of the LCD unit, for conveying light
from light sources located at sides of the light guide;
a circuit board; and
an extension section extending from said base sheet comprising a portion extending
along a bottom surface of said light guide, said extending portion having a bottom
surface bonded to the circuit board by said weak adhesive layer.
Description
FIELD OF THE INVENTION
The present invention relates to a movable contact unit having a plurality of
push switches used in operation section of downsized electronic equipment such
as cellular phone and the like, panel switch using the movable contact units and
electronic equipment having the panel switch.
BACKGROUND OF THE INVENTION
Nowadays, along with the advance of performance and diversity of downsized
electronic equipment such as cellular phones and the like, panel switch having
a plurality of arranged push switches and mainly used in operation section of them
is required to have high accuracy and usability as well as cheap prices.
A conventional movable contact unit for push switches used in operation section
of downsized electronic equipment and a panel switch using the movable contact
units are described with reference to FIG. 10 through FIG. 13. Here,
perpendicular scale in each drawing is drawn enlarged for easy understanding.
FIG. 10 shows a cross-sectional front view of a conventional movable contact
unit, FIG. 11 shows an exploded perspective view of the conventional movable contact
unit. In FIG. 11, movable contact 1 formed from a resilient thin metal sheet
has a dome shape and base sheet 2 formed from a flexible insulation substrate
has a plurality of through holes 2A in predetermined positions. Movable
contact 1 is placed in each through hole 2A of base sheet 2.
Cover sheet 3 formed from a flexible insulation substrate and coated with
adhesive material 3A on bottom surface is bonded on individual convex upper
surface of movable contact 1 and is fixed on base sheet 2 to form
a movable contact unit 4 having a plurality of push switches.
FIG. 12 shows a cross-sectional front view of a panel switch using an above
mentioned conventional movable contact unit, and FIG. 13 shows an exploded perspective
view of the panel switch. In FIG. 13, stationary contact substrate 5 has
a plurality of stationary contact 7 consisted of central stationary contact
7A and peripheral stationary contact 7B on predetermined positions
of hard plate-like insulation board 6. Peripheral edge of each movable contact
1 of movable contact unit 4 is placed on corresponding peripheral
stationary contact 7B such that convex bottom surface of movable contact
1 faces each central stationary contact 7A, basing on small hole
5A of substrate 5 and small hole 2B of base sheet 2
for positioning, to form panel switch 8 having a plurality of arranged push switches.
Panel switch 8 mentioned above is mounted on an operation section of
electronic equipment. When convex upper surface of a movable contact 1 is
depressed by operation button (not shown) through cover sheet 3, convex
bottom surface of movable contact 1 performs resilient motion with a click
feeling to connect central stationary contact. Then, central stationary contact
7A of stationary contact substrate 5 and outside stationary contact
7B are electrically coupled to make a push switch ON stage. Upon release
of depression from operation button, a resilient restoring force of movable contact
1 acts to disconnect convex bottom surface from central stationary contact
7A to return to push switch OFF stage as shown in FIG. 12.
However, in above mentioned conventional movable contact unit 4 and
panel switch using the movable contact unit, ingress of dust between movable contact
unit 4 and stationary contact substrate 5 moves in between movable
contact 1 and stationary contact 7 to cause problems of loose connection
in push switch of panel switch, during use of electronic equipment incorporated
with panel switch having a combination of movable contact unit 4 and stationary
contact substrate 5.
SUMMARY OF THE INVENTION
A movable contact unit disclosed in this invention comprises:
(a) a base sheet formed from a flexible insulation substrate having a plurality
of through holes in predetermined positions;
(b) a plurality of movable contacts placed freely in vertical motion in
respective through holes of the base sheet;
(c) a cover sheet formed from a flexible insulation substrate and bonded
on upper surface of the base sheet, using adhesive coated on bottom surface of
the cover sheet, to hold respective movable contacts in predetermined positions
in the through holes of the base sheet; and
(d) a weak adhesive layer applied on bottom surface of the base sheet except
the through holes.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a cross-sectional front view of a movable contact unit used in a first
preferred embodiment of the present invention.
FIG. 2 is an exploded perspective view of a movable contact unit used in the
first preferred embodiment of the present invention.
FIG. 3A is a cross-sectional schematic view for a manufacturing method of a
movable contact unit used in the first preferred embodiment of the present invention.
FIG. 3B is a cross-sectional schematic view for a forming method of a movable
contact unit used in the first preferred embodiment of the present invention.
FIG. 4 is a bottom view of a movable contact unit used in the first preferred
embodiment of the present invention.
FIG. 5 is a cross-sectional front view of a panel switch using a movable contact
unit used in the first preferred embodiment of the present invention.
FIG. 6 is an exploded perspective view of a panel switch using a movable contact
unit used in the first preferred embodiment of the present invention.
FIG. 7 is a partially cross-sectional front view of an electric equipment having
a panel switch using a movable contact unit used in the first preferred embodiment
of the present invention.
FIG. 8 is a partially cross-sectional front view of another example of electric
equipment having a panel switch used in the first preferred embodiment of the present invention.
FIG. 9 is an appearance view of a movable contact unit used in the first preferred
embodiment of the present invention.
FIG. 10 is a cross-sectional front view of a conventional movable contact unit.
FIG. 11 is an exploded perspective view of a conventional movable contact unit.
FIG. 12 is a cross-sectional front view of a panel switch using a conventional
movable contact unit.
FIG. 13 is an exploded perspective view of a panel switch using a conventional
movable contact unit.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is described by following preferred embodiments with reference
to FIG.
1 through FIG.
9. Here, perpendicular scale in each drawing
is drawn enlarged for easy understanding and the similar configuration described
in the conventional art have the same reference marks and the detailed descriptions
thereof are simplified.
First Preferred Embodiment
FIG. 1 is a cross-sectional front view of a movable contact unit used in the
first preferred embodiment of the present invention and FIG. 2 is an exploded perspective
view of the movable contact unit.
In FIG. 2, movable contact
1 formed from a resilient thin metal sheet
has
a round dome shape and base sheet
2 formed from a flexible insulation substrate
has a plurality of through holes
2A in predetermined positions. Movable
contacts
1 are placed freely in vertical motion in respective through holes
2A of base sheet
2. Cover sheet
3 formed from a flexible insulation
substrate and coated with adhesive material
3A on bottom surface is bonded
on individual convex upper surface of movable contact
1 to secure movable
contact
1 on upper surface of base sheet
2.
The above mentioned configuration is the same as conventional art but movable
contact unit
10 used in the first preferred embodiment for panel switch
having a plurality of push switches is provided with weak adhesive layer
9
on bottom surface of base sheet
2 except through holes
2A.
A manufacturing method of movable contact unit
10 having weak adhesive
layer
9 is described with reference to cross-sectional view shown in FIG.
3.
First, whole bottom surface of flexible insulation substrate
11 of
base sheet
2 is coated with a weak adhesive material to form weak adhesive
layer
9 on the surface as shown in FIG.
3A.
In addition, a combination of flexible insulation substrate
11 and second
flexible insulation substrate
12, thinner than flexible insulation substrate
11, bonded under weak adhesive layer
9 is die-punched to provide
a plurality of through holes
2A in predetermined positions.
After the above processing, movable contacts
1 are placed on every through
hole
2A from upper side of flexible insulation substrate
11, corresponds
to base sheet
2 as shown in FIG.
3B.
Then, cover sheet
3 formed from a flexible insulation substrate and
coated with adhesive material
3A on bottom surface is bonded on individual
convex upper surface of movable contact
1 to hold movable contact
1,
then cover sheet
3 is fixed on upper surface of base sheet
2.
Finally, second flexible insulation substrate
12 is peeled off from
bottom surface of weak adhesive layer
9 to form a movable contact unit
10
having weak adhesive layer
9.
Here, weak adhesive material coated on bottom surface of flexible insulation
substrate
11 contains a higher ratio of hardener to base resin compared
with ordinary adhesive materials. Moreover, coating thickness of 5 to 10 □m
for weak adhesive layer
9 is approx. one third of typical adhesive coating
thickness. Bonded substrate can be peeled off easily without any damage on the
surface, as peeling-off strength from weak adhesive layer
9 formed as mentioned
above is of the order of approx. 100 gf/25 mm that is about one tenth for typical adhesives.
In addition, in above mentioned manufacturing method, through holes
2A
provided on base sheet
2 are punched out in larger size than outer diameter
of round dome shaped movable contact
1 as shown in a bottom view of movable
contact unit in FIG.
4.
Movable contact
1 is fixed by cover sheet
3 to keep a certain
gap around movable contact
1 from inside diameter of through hole
2A,
correspond to weak adhesive layer
9 (shown in hatching in the drawing).
Consequently, movable contact unit
10 can perform with an acceptable
click feeling by depressing operation, as weak adhesive layer
9 does not
influence round dome shaped movable contact
1.
Moreover, cover sheet
3 may not be applied individually as mentioned
above, but can be a single sheet for fixing a plurality of neighboring movable
contacts all together.
Additionally, if weak adhesive layer
9 is applied keeping a
certain gap left from circumference of through hole
2A, adhesive layer
9
affects on movable contact
1 far less than conventional art.
FIG. 5 is a cross-sectional front view of a panel switch using above mentioned
movable contact unit
10, and FIG. 6 is an exploded perspective view of the
panel switch. In FIG. 6, stationary contact substrate
5 has a plurality
of stationary contact
7 consisted of central stationary contact
7A
and peripheral stationary contact
7B on predetermined positions of hard
plate-like insulation board
6: that is similar to conventional art.
Peripheral edge of each movable contact
1 of movable contact unit
4 is placed on corresponding peripheral stationary contact
7B such
that convex bottom surface of movable contact
1 faces each central stationary
contact
7A with a certain gap.
Basing on small hole
5A of substrate
5 and small hole
2B
of base sheet
2 for positioning, movable contact unit
10 is stacked
on stationary contact substrate
5 and is bonded together using weak adhesive
layer
9 applied on bottom surface of base sheet
2 of movable contact
unit
10 to form panel switch
13 having a plurality of arranged push switches.
Namely, operation of panel switch
13 to depress convex upper surface
of round dome shaped movable contact
1 through cover sheet
3 is the
same as conventional art, but ingress of dust between base sheet
2 and stationary
contact substrate
5 is prevented, as bottom surface of base sheet
2
of movable contact unit
10 and stationary contact substrate
5 is
bonded together using weak adhesive layer
9.
In addition, even if ingress of dust between the two occurred, dust can not move
further, which contributes to little occurrence of loose connection of push switch,
and movable contact
1 performs a steady resilient action, as a steady positioning
of each movable contact
1 and corresponding each stationary contact
7
is maintained.
Moreover, weak adhesive layer
9 to bond movable contact unit
10
with stationary contact substrate
5 together has a weak peeling-off strength
as afore-mentioned, the same as conventional art without any weak adhesive layer
9, in case of, for example, combination change of movable contact unit
10
and stationary contact substrate
5, if necessary, movable contact unit
10
can be peeled off easily from bonded stationary contact substrate without any damage
and both can be reused.
Next, FIG. 7 is a partially cross-sectional front view of a downsized electric
equipment having a panel switch used in the first preferred embodiment.
As shown in FIG. 7, a plurality of operation buttons
14 formed from resilient
insulation material and capable of free vertical motion exposes from upper housing
15A, which performs as an operation section of the electric equipment. A
panel switch is fixed on fixing member
16 placed surroundings of a plurality
of operation button
14 using double-faced member
17. Convex upper
surface of each movable contact
1 of movable contact unit
10 touches
bottom portion of each operation button
14 through cover sheet
3
Additionally, bonded stationary contact substrate
5 using weak
adhesive layer
9 applied on bottom surface of base sheet
2 of movable
contact unit
10 plays also a role of circuit board
18 for the electric
equipment held in bottom side housing
15B. Namely, central stationary contact
7A and peripheral stationary contact
7B of each stationary contact
7 are mounted on upper surface of circuit board
18 directly.
Electric equipment with above configuration performs with steady operation
condition and with little occurrence of loose connection in push switches of operation
section due to a good dust-proof property as well as low machine profile and cheep
prices. Moreover, movable contact unit
10 can be peeled off easily from
circuit board
18 which acts as stationary contact substrate, together with
weak adhesive layer
9, to exchange operation button
14 or fixing
member
16 for a modification of operation section design of electronic equipment.
Second Preferred Embodiment
FIG. 8 is a partially cross-sectional front view of a downsized electric equipment
having a panel switch used in the second preferred embodiment of the present invention.
As shown in FIG. 8, the electric equipment comprises LCD (liquid crystal display)
unit
20 exposed from upper side housing
19A, light guide
21
secured on bottom surface of the housing, and display section
23 having
light source
22 disposed at surrounding sides of the display section. Transparent
protective lens
24 is mounted on upper surface of LCD display unit
20.
In addition, extension section
26A extended from base sheet
26
of
movable contact unit
25 of the panel switch is provided at the bottom surface
side of light guide
21, and is bonded on circuit board
28 of the
electric equipment with weak adhesive layer
27 coated on bottom surface,
to mount the extension section such that contacts bottom surface of light guide
21.
Movable contact unit
25 has an extended section of a predetermined
length in one end of base sheet
26 consisted of whitish flexible insulation
substrate with weak adhesive layer
27 coated on bottom surface as shown
in an appearance view in FIG.
9. Extension section
26A is bonded
flatly on plate-like circuit board
28 to act a light reflector for light
guide
21.
The invention thus contributes a development of electronic equipment having brighter
and steadier display section
23 with cheaper cost prices.
According to the above, as the bottom surface of base sheet of movable
contact unit is bonded stationary contact substrate using weak adhesive layer,
not only the ingress of dust between movable contact unit and stationary contact
substrate is prevented but the dust, even if entered, is difficult to move further,
which contributes to little occurrence of loose connection of push switch and to
keep a steady positioning of each movable contact and corresponding each stationary contact.
Moreover, the movable contact unit has an advantageous capability of peeling
movable contact unit off from bonded stationary contact substrate easily and without
any damage.
*
