Computer keyboard key device made from a rigid printed...

Details Computer keyboard key device made from a rigid printed... Computer keyboard key device made from a rigid printed...

2001-01-19

2002-05-14

Donovan, Lincoln (Department: 2832)

Electricity: circuit makers and breakers

Solid contact

Membrane type

C200S345000, C400S491200

Reexamination Certificate

active

06388219

ABSTRACT:

BACKGROUND OF INVENTION
1. Field of the Invention
The present invention discloses a key device for a computer keyboard. More particularly, the key circuit of the computer keyboard is made from a rigid printed circuit board.
2. Description of the Prior Art
Please refer to FIG.
1
and FIG.
2
.
FIG. 1
is a schematic diagram of a known computer keyboard
10
. A sectional view along line
2
—
2
of the computer keyboard
10
is shown in FIG.
2
. The computer keyboard
10
has a plastic housing
12
and a plurality of key devices
14
fixed inside the plastic housing
12
.
The key device
14
includes two stacked flexible printed circuit board
16
, and
18
. The bottom surface
20
of the upper flexible printed circuit board
16
, and the upper surface
22
of the lower flexible printed circuit board
18
each have a conductive segment
24
and
26
respectively. A soft plastic segment
28
is installed between the two printed circuit boards
16
,
18
. A metal plate
13
is installed on the printed circuit board
16
. A supporting plate
17
is installed under the printed circuit board
18
to provide the supporting force needed for pushing the key device
14
. The soft plastic segment
28
has a hole
30
positioned between the conductive segments
24
,
26
, and the hole
30
makes a gap between the conductive segments
24
,
26
.
The key device
14
further includes a keycap
32
, a scissors-like support
34
that is moveable in up and down directions to fix the keycap
32
onto the flexible printed circuit board
32
. An elastic component
36
, installed between the keycap
32
and the flexible printed circuit board
16
, upwardly supports the keycap
32
in an elastic manner. When the keycap
32
is pushed downward, the bottom surface of the elastic component
36
will touch the conductive segment
24
of the flexible printed circuit board
16
, causing the conductive segment
24
to form an electrical connection with the conductive segment
26
of the flexible printed circuit board
18
.
Please refer to FIG.
3
.
FIG. 3
is a schematic diagram of the partial structure of another key device
40
according to the prior art for a computer keyboard
10
. The key device
40
includes two stacked flexible printed circuit boards
42
and
44
, which are adhered together. Isolation layers
54
and
56
are installed on the flexible printed circuit boards
42
and
44
, respectively. The isolation layers
54
is printed on the bottom surface
46
of the flexible printed circuit board
42
, and the isolation layer
56
is printed on the upper surface
48
of the flexible printed circuit board
44
. The isolation layers
54
,
56
encircle the conductive segments
50
and
52
, respectively. Because the isolation layer
54
protrudes from the bottom surface
46
of the flexible printed circuit board
42
, and the isolation layer
56
protrudes from the upper surface
48
of the flexible printed circuit board
44
, the thickness of the two isolation layers
54
and
56
creates a gap between the two conductive segments
50
and
52
.
Because of their flexible nature, decoders cannot be soldered onto the flexible printed circuit boards
16
,
18
and
42
,
44
. Therefore, the computer keyboard
10
can not produce decoded key signals. Instead, it must be connected to a decoding circuit (not shown) through signal lines to produce the corresponding decoded key signals. Furthermore, the supporting plate
17
is used only to provide the supporting force needed to push the key device
14
.
SUMMARY OF THE INVENTION
It is therefore an objective of the present invention to provide a key device that uses a rigid printed circuit board to solve the above-mentioned problems.
Briefly, the present invention provides a way to combine a rigid printed circuit board and a flexible printed circuit board together to form a different key device upon which can be soldered a decoder. The computer keyboard can thus produce decoded key signals without the use of an external decoding circuit.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings.


REFERENCES:
patent: 5743383 (1998-04-01), Yano et al.
patent: 5799772 (1998-09-01), Sanda et al.
patent: 5842798 (1998-12-01), Su
patent: 5847337 (1998-12-01), Chen
patent: 5973281 (1999-10-01), Tsai
patent: 6107584 (2000-08-01), Yoneyama

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