JPS61253726A - Rectangular contact support for keyboard - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial application field-k Dq day 1-) Ir13J, (714)7
% ml y hf E hl=rectangular contact carrier for a keyboard with a contact field consisting of two contact contact paths located opposite each other,
It also concerns a type in which the two contact paths, which are separated from one another by an air gap, are produced by first applying a silver paste and then covering it with a graphite paste by means of a screen printing method.

BACKGROUND OF THE INVENTION Contact carriers of the type described above in the form of switch foils are currently produced by screen printing methods. The problem in this case is simply that the conductor tracks and contact areas applied in the form of silver paste must be protected from sulfur-containing air. The solution to this problem is achieved in a known manner by applying a graphite paste that completely covers the contact paths and contact areas.

However, according to the customary method, both the contact path and the contact area are arranged in such a way that they run parallel to one side of the rectangular contact carrier in the contact field.In order to make the contact contact resistance as low as possible, the contact area It is essential to keep the distance between the contact paths in the range as small as possible. In this case, if there are production errors in the production direction or in the direction perpendicular to this production direction due to slight deviations between the contact contact path and the graphite layer in which the contact support is produced by screen printing, the contact field in the contact area A further problem arises in that the necessary airtight covering of each contact path of is no longer available. Along with this, the incidence of defective products also increases.

Problem to be Solved by the Invention It is an object of the present invention to geometrically construct and arrange the contact paths forming the contact areas in such a way that even if manufacturing errors occur, the number of defective products is significantly reduced.

Means for Solving the Problem The structural means of the invention for solving the problem are arranged obliquely, particularly preferably at an angle of 45°, and parallel to each other in the contact field. At the point.

This arrangement of the contact paths forming the working contact areas makes it possible to separate the individual contact paths and the The distance to the gap is increased by a factor, in which case there is no need to enlarge the outer dimensions of the contact carrier or the individual contact fields. Therefore, by arranging the contact contact paths in this manner, variations in manufacturing errors are allowed within a relatively large range both in the manufacturing direction and in the direction perpendicular to the manufacturing direction, which increases the incidence of defective products. There isn't.

Embodiment Next, one embodiment of the present invention will be explained in detail with reference to the drawings. A rectangularly designed contact carrier l for a keyboard has a plurality of contact fields 2, which are assigned to individual keys. These contact fields have a contact path 3.4 for each key, both contact paths being separated from each other by an air gap 5. Such a contact carrier 1 in the form of a switch foil is usually produced by screen printing in such a way that the contact traces in the form of a conductor are first applied to the contact carrier 1 in the form of a silver paste. The contact paths are then completely surrounded by an application of graphite paste in order to protect them from corrosion phenomena due to sulfur-containing air. This forms a contact surface 8.9.

In the area of the contact surfaces 8, 9, the contact contact paths 2, 3 forming the contact area are additionally protected by the application of a covering lacquer 7, which covers the contacts shown in dashed lines in FIG. It is applied outside the area of the support 1.

Activation of the contact takes place by bridging the contact surfaces 8 and 9 by means of a small spherical contact pillar (not shown) of silicone rubber mat.

In order to obtain an optimum distance between the contact path 3.4 and the air gap 5, the contact paths 3 and 4 are arranged in the range of the contact field 2 activated by the key.
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This is the angle with respect to one side of the rectangular contact support 1. In this case, the advantage arises that the distance 6 existing between the contact contact path 3 and the air gap 5 is increased by a factor 0, compared to the known contact contact paths arranged parallel to the sides of the rectangle. Thereby, production errors that occur when producing the contact carrier l by screen printing can be compensated for very easily, since in this case there is a relatively large margin.

Effects of the Invention Due to the construction of the invention, the contact paths 3 and 4 are each inclined in the area of the contact field 2 at an angle of 45° to one side of the rectangular contact carrier l. Because they are arranged parallel to each other, this significantly increases the distance between the contact paths in the contact area, without any need to change the external dimensions of the contact field 2. Also, when manufacturing by screen printing, even if there is a manufacturing error, it will be defective! :! , since the a-viability rate is also slightly suppressed, its industrial utility value is extremely large.

[Brief explanation of the drawing]

Figure 1 is a top view of one contact field; Figure 2 is a top view of one contact field;
3 is a sectional view of the contact field along the line ■--■ in the figure, and FIG. 3 is a partially detailed plan view of the contact field shown in FIG. 1. ! ...Contact support, 2...Contact field, 3, 4
...Contact contact path, 5...Air gap, 6...Distance between contact contact path and air gap, 7...Coating lacquer, 8, 9...Contact surface

Claims (1)

Claims: A rectangular contact support for a keyboard (2) with a contact field (2) consisting of two contact contact paths (3, 4) belonging to individual keys and located opposite each other. 1), and the air gap (
5) double contact contact paths (3, 4) separated from each other by
is formed by first applying silver paste and then coating with graphite paste by screen printing, in which both contact contact paths (3, 4) are formed on one side of the contact carrier (1). characterized in that they are arranged diagonally and parallel to each other in the contact field (2),
Rectangular contact support for keyboard.