JPH01132016A - Membrane switch - Google Patents

Abstract

PURPOSE:To eliminate molding work using dies and simplify circuit wiring by forming an electronic part containing hole in a circuit board formed by folding an electrode sheet for a plurality of times, and disposing contact electrodes near the surface of this circuit board and the circuit conductor relating to the electronic part near the back surface of it. CONSTITUTION:A circuit board 30 formed by folding an electrode sheet 20, with spacers 21 put between its folds, secures a thickness for the height of an electronic part 8. Hence, if the electronic part 8 is housed in an electronic part containing hole 26 penetrating through the circuit board 30, an ornamental surface sheet 28 can be formed flat without protrusion of the electronic part 8 on the surface of the circuit board 30. Because the circuit board 30 is of a multi-layer structure, contact electrodes 22, 23, circuit wiring relating to the contact electrodes 22, 23, circuit wiring relating to the electronic part 8, etc., are wired separately in different layers. Need of dies for molding work for the ornamental surface sheet 28 is thus eliminated, and complication of circuit wirings can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a membrane switch, and particularly to a membrane switch equipped with electronic components.

[Prior art] Membrane switches have advantages such as thinness and durability, so they are widely used in the operation parts of electronic devices such as office automation equipment, microcomputers, and calculators. By mounting electronic components such as LEDs (light emitting diodes), their versatility is becoming more and more widespread.

FIGS. 3 and 4 show examples of the conventional structure of membrane switches, which have a laminated structure in which a spacer 3 is sandwiched between a pair of base sheet l and upper sheet 2 made of polyester film. At the contact holes 4 of the spacer 3, contact electrodes 5.6 provided opposite to the base sheet l and the upper sheet 2 are opened and closed to obtain electrical signals. As shown in FIG. 4, a circuit conductor 9 for mounting an electronic component 8 is wired in the electronic component storage hole 7 of the spacer 2 along with the wiring of the contact electrode 5 by printing or the like. The electronic component 8 is fixedly connected to the circuit conductor 9 using a conductive adhesive, and is further covered with a protective sealing adhesive. Further, the surface of the upper sheet 2 is covered with a decorative surface sheet 10, and the decorative surface sheet IO forms an operation surface.

Note that reference numeral 11 is a hard substrate made of galvanized steel plate or the like, and a base sheet 1 is pasted onto the hard substrate 11 to ensure its flatness.

[Problems to be Solved by the Invention] However, in such a membrane switch, in consideration of the height of the electronic component 8, the upper sheet 2 and the surface decorative sheet IO are each given an uneven finish to protrude upward. , it is necessary to provide a space for arranging the electronic components 8, and there is a problem that the molds for processing the irregularities of the upper sheet 2 and the surface decorative sheet 10 are expensive.

In addition, since it is necessary to arrange the contact electrodes 5, electronic components 8, circuit conductors 9 related to these, and other wiring on one plane, problems such as circuit wiring tend to become complicated are caused. arise.

This invention was made in view of the above circumstances, and its purpose is to provide a membrane switch that secures a space for arranging electronic components by machining the holes and reduces the complexity of circuit wiring. There is a particular thing.

[Means for Solving the Problems] The membrane switch according to the present invention includes contact electrodes that are arranged in opposing positions near the surface of a multilayer circuit board formed by folding a flexible electrode sheet a plurality of times. A circuit conductor for mounting an electronic component is arranged near the back surface at a position apart from the contact electrode, and a circuit conductor for mounting an electronic component is arranged so as to face the front surface side. It is equipped with an electronic component storage hole.

[Example 1] An example of a membrane switch according to the present invention will be described below with reference to FIGS. 1 and 2.

In this embodiment, an electrode sheet 20 made of a polyester film is folded three times, with a spacer 21 interposed between each fold to form a multilayered circuit board 30. Contact electrodes 22.23 are provided on the first layer close to the surface of the circuit board 30, facing each other at the contact hole 24 of the spacer 21, and are spaced apart from the contact electrodes 22.23. electronic components 8 on the third layer electrode sheet 20 near the back surface.
A circuit conductor 25 for mounting the circuit board 30 is provided, and an electronic component storage hole 26 is formed above the circuit conductor 25, penetrating the electrode sheet 20 and the spacer 21 to the surface of the circuit board 30. The electronic component 8 is accommodated in the electronic component storage hole 26.

In the above case, the electrode sheet 20 is made of one sheet, as shown in the exploded view of FIG. 2, and a tail portion T is provided with a narrowed width and a protruding portion so as to extend a part of the sheet. On the other hand, the wiring extended from the tail part T is sequentially distributed and mounted in four parts of W-Z. That is, from the area W adjacent to the tail part T, the second area X1 the third area Y1 the fourth area Z
The via wiring 27° is mounted and electrically connected, and the electronic component storage holes 26 are opened in the second to fourth areas X to Z, respectively.

A plurality of lower contact electrodes 22 are provided in the third area Y, and a plurality of upper contact electrodes 22 are provided in the fourth area Z.
A plurality of electrodes 3 are provided in alignment with each other in correspondence with the lower contact electrode 22. That is, the electrode sheet 20 is bent at the bending position A-A between each area WZ.
, B-BSC to C, and a spacer 21 is interposed between each to form a multilayer structure as shown in FIG. The contact hole 24 is thicker than ~1.5nun, and the electronic components 8 are arranged so as to face the surface thereof, penetrating the electronic component storage holes 26, and the contact electrodes 22, 23 are provided in the spacer 21. so that they are facing each other. A decorative surface sheet 28 is attached to the surface of the circuit board 30, and the decorative surface sheet 28 forms an operation surface.

Therefore, in the membrane switch of this embodiment, the circuit board 30 has a thickness equal to the height of the electronic component 8 by folding the electrode sheet 20 and interposing spacers 21 between the folds. Therefore, when the electronic component 8 is stored in the circuit board 30 with the electronic component storage hole 26 penetrated, the electronic component 8 does not protrude from the surface of the circuit board 30, and the surface decorative sheet 28 is kept flat. can be formed into

Further, since the circuit board 30 has a multilayer structure, the contact electrodes 22.23, the circuit wiring related to the contact electrodes 22.23, the circuit wiring related to the electronic component 8, etc. are distributed and wired in different layers. Therefore, it is possible to eliminate the complexity of circuit wiring without causing each circuit wiring to cross over.

In the above embodiment, the circuit board 30 has a three-layer structure, but it may have a multilayer structure with more layers depending on the height of the electronic component 8 to be mounted.

[Effects of the Invention] As explained above, the membrane switch according to the present invention can have the following effects.

(+) Since the electrode sheet is folded multiple times to form a multilayer circuit board, its thickness allows for the height of electronic components, and holes for storing electronic components are formed in the circuit board. By storing the electronic components in the circuit board, the electronic components can be prevented from protruding onto the surface of the circuit board, and the surface portion can be formed flat. Therefore, there is no need to use expensive molds to create irregularities on the surface as in the past.
Cost reduction can be achieved.

(2) Contact electrodes are placed near the front surface of the multilayer circuit board, and circuit conductors for electronic components are placed near the back surface, so the circuit wiring for electronic components and the circuit wiring for contact electrodes are on different layers. It is possible to reduce the complexity of the circuit wiring.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an embodiment of a membrane switch according to the present invention, FIG. 2 is a developed view of an electrode sheet portion in the same embodiment, and FIG. 3 is a front sectional view showing an example of the conventional structure of a membrane switch. , FIG. 4 is a plan view of the base sheet in the conventional example. 8...Electronic component, 20...Electrode sheet, 21...Spacer, 22.23...Electrode for contact, 24...For contact Hole, 25... Circuit conductor, 26... Electronic component storage hole, 27... Via wiring, 28... Decorative surface sheet, 30...・Circuit board, T...Tail part, A-A-B-B-C-C...Bending position, W...1st area, X... ...Second area, Y...Third area, Z...Fourth area.

Claims (1)

[Claims] Contact electrodes (22, 23) are provided in the vicinity of the surface (Y, Z) of a multilayer structure circuit board (30) formed by folding a flexible electrode sheet (20) multiple times in an opposing state. A circuit conductor (25) for mounting electronic components is arranged near the back surface (W) at a position away from the contact electrode, facing the front surface side, and a multilayer portion of the electrode sheet is placed on the front surface side of the circuit conductor. A membrane switch characterized by having an electronic component storage hole (26) that is open.