JPS5936373B2 - keyboard switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a keyboard switch in which a common electrode and a plurality of individual electrodes are provided facing each other and are operated by pressing the facing portions.

Conventionally, a keyboard switch used for a data input device, etc., has a large number of comb-shaped individual electrodes 2 on a printed circuit board 1, as shown in FIGS. 1 and 2. A gold plating layer 3 is applied to the surface of the individual electrodes 2, and then insulating ink is printed in a desired pattern except for the individual electrodes 2 to form an insulating layer 4.

Thereafter, a resilient common electrode 5 made of a conductive rubber sheet is placed on the insulating layer 4, and the individual electrodes 2 and
Symbols such as letters and numbers corresponding to 6...
It is assembled by overlapping the protective sheets 7 provided with .
Alternatively, instead of printing the insulating layer 4 on the printed circuit board 1, an insulating thin plate 8 made of plastic or the like as shown in FIG. Hole 8a at the position corresponding to...
. . , and this thin plate 8 is mounted on the printed circuit board 1.

To operate this keyboard switch, press any one of the symbols 6 on the protective sheet 7 with a finger 9 or a push rod (not shown) as shown in FIG. 2 and the common electrode 5 can be brought into contact with each other, and the individual electrodes 2 can be electrically turned on.

Incidentally, the thickness of the individual electrode 2 is approximately 55 μm when the thickness of the gold plating layer 3 is added.

However, the thickness of the insulating layer 4 formed by one printing of insulating ink is about 10 μm, and therefore, in order to form the insulating layer 4 thicker than the individual electrodes 2, it is necessary to
It is necessary to print more than once. Therefore, printing misalignment is likely to occur during printing, and the corner portions 4 of the insulating layer 4
In a (see Figure 4), the person curls up and curls up,
The repulsive force when the pressure on the common electrode 5 is released is weakened (
The sharpness of the ON/OFF switch becomes poor), and
Chattering occurs when turned off. In addition, individual electrode 2
However, it has drawbacks such as being easily stained by insulating ink.
On the other hand, when using the insulating thin plate 8, burrs are likely to be generated when forming the plurality of holes 8a by punching, and after the keyboard switch is assembled, the burrs are removed from the thin plate 8. It comes off and adheres to the individual electrode 2, causing poor contact in the switch. In addition, when the number of individual electrodes 2 is extremely large, such as 100 or more, holes 8a...
. . and the printed circuit board 1 provided with the individual electrodes 2 . . . are difficult to align, and misalignment easily occurs. In view of the above drawbacks, the present invention provides a keyboard switch which uses a photosensitive film resist instead of the insulating layer 4 or the insulating thin plate 8, has good characteristics, is easy to manufacture, and is inexpensive. below,
To explain the keyboard switch of the present invention with reference to the drawings, FIG. Layer 3 is formed.

Further, a photosensitive film resist 10 having a window 10a for exposing the individual electrodes 2 is provided on the entire surface of the printed circuit board 1. On the film resist 10, as shown in FIG. 6, there is a resilient common electrode 5 made of a conductive rubber sheet or a pressure-sensitive conductive silicone rubber sheet.
, and symbols 6 such as letters and numbers (see FIG. 2) are sequentially overlapped to form a keyboard switch. Therefore, the method for forming the photosensitive film resist 10 will be explained with reference to FIG. 7. First, as shown in FIG. A photosensitive film resist 10 having a thickness of approximately 100 μm is placed on the entire surface of the printed circuit board 1 including the individual electrodes 2, and laminated by thermocompression bonding. Next, as shown in FIG.
and forming an uncured portion 10c. Finally, in Figure d, the photosensitive film resist 1 is etched with an etching solution.
The photosensitive film resist 10 having a desired pattern can be formed by etching away the uncured portion 10c of 0 to form the window portion 10a. The corner 10d of the window 10a formed by the etching method can be formed to have an acute angle, and the film resist 10 can have a desired thickness. As described above, the present invention interposes a photosensitive film resist 10 having a window 10a for exposing the individual electrodes 2 between the individual electrodes 2 and the common electrode 5 formed on the printed circuit board 1. The photosensitive film resist 10 can be of any thickness, and unlike the conventional insulating layer 4, there is no need to repeatedly print insulating ink several times, and individual electrodes can be easily printed. 2 and the common electrode 5 can be easily set to an appropriate value.

Furthermore, the window portion 10a of the photosensitive film 10 can be etched very easily by the etching method, and the corner portion 10a of the window portion 10a can be etched very easily.
d can be formed at an acute angle, and the switch's 0N, 0
The sharpness at FF is good, and the occurrence of chattering at 0FF can be prevented. Furthermore, the position of the window portion 10a can be provided with high accuracy in correspondence with the individual electrode 2, and there is no difficulty in positioning as in the case of using the insulating thin plate 8 of the conventional example, and manufacturing is easy. This has the remarkable effect of providing an inexpensive keyboard switch.

[Brief explanation of the drawing]

Figures 1 to 4 relate to a conventional keyboard switch.
Fig. 1 is a plan view of the main part showing individual electrodes provided on the printed circuit board, Fig. 2 is an exploded perspective view of the main part, Fig. 3 is a perspective view of the main part of the insulating thin plate, and Fig. 4 is a cross-sectional side view of the main part. , FIG. 5 to FIG. 7 relate to the keyboard switch of the present invention, FIG. 5 is a plan view of the main part explaining the individual electrodes on the printed circuit board, FIG. 6 is a cross-sectional side view of the main part, and FIG. 7 a- d is a cross-sectional side view of a main part illustrating each step of a method for forming a photosensitive film resist. DESCRIPTION OF SYMBOLS 1...Printed circuit board, 2...Individual electrode, 5...Common electrode, 10...Photosensitive film resist, 10a... Window section.

Claims (1)

[Claims] 1. A photosensitive film resist having a window portion for exposing the individual electrodes is formed on a printed circuit board on which a plurality of individual electrodes are provided, and an elastic conductive film resist is formed on the photosensitive film resist. A common electrode is provided, a small space is provided between the common electrode and the individual electrodes, and the common electrode is pressed to contact the individual electrodes to obtain electrical continuity. keyboard switch.