JP2672820B2 - Membrane switch - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane switch, and more particularly to a membrane switch equipped with an electronic component. [Prior Art] Since a membrane switch has advantages such as thinness and durability, it is widely used for operating parts of electronic equipment such as OA equipment, microcomputers, and calculators. By mounting electronic parts such as LEDs (light emitting diodes), its versatility is further expanded. FIGS. 3 and 4 show an example of a conventional structure of a membrane switch, which has a laminated structure in which a spacer 3 is sandwiched between a base sheet 1 and an upper sheet 2 forming a pair, which are made of a polyester film. Contact hole 4 of spacer 3
At this portion, the contact electrodes 5 and 6 provided in a state of facing the upper sheet 2 of the base sheet 1 are opened and closed to obtain an electric signal, and at the same time, the base sheet 1 is provided with electrons of the spacer 2. As shown in FIG. 4, a circuit conductor 9 for mounting the electronic component 8 is laid in the component housing hole 7 together with the wiring of the contact electrode 5 by print printing or the like, and the electronic component 8 is electrically conductive. Circuit conductor 9 with a conductive adhesive
Is fixedly connected to and is further covered with a sealing adhesive for protection. Further, the surface of the upper sheet 2 is further covered with a surface decorative sheet 10, and the surface decorative sheet 10 forms an operation surface. Note that reference numeral 11 is a hard substrate made of a galvanized steel plate or the like, and the base sheet 1 is provided on the hard substrate 11.
Is affixed 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 10 are each subjected to unevenness processing so as to project upward. However, there is a problem in that a space for disposing the electronic component 8 has to be provided, and a mold for the uneven processing of the upper sheet 2 and the surface decorative sheet 10 is expensive. Further, since the contact electrode 5, the electronic component 8, the circuit conductor 9 associated therewith, and other wirings need to be arranged in a line on one plane, there is a problem that the circuit wiring is likely to be complicated. Occurs. The present invention has been made in view of the above circumstances, and an object thereof is to provide a membrane switch that secures an electronic component placement space by drilling or the like and reduces complexity of circuit wiring. It is in. [Means for Solving Problems] A membrane switch according to the present invention has a multilayer circuit in which a flexible electrode sheet having a rectangular shape as a whole is folded a plurality of times through bending lines parallel to the edges thereof. In the plate, spacers are respectively interposed between the folded electrode sheets, and an electronic component which is mounted on the electrode sheet and penetrates through the overlapping positions of the electrode sheet and the spacer and which projects an electronic component from the surface is housed. It is characterized by having a component storage hole. [Embodiment] An embodiment of the 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, and a spacer 21 is interposed between each of the folds to form a multilayer circuit board 30. Contact electrodes 22, 23 are provided on the first layer close to the surface of the circuit board 30 so as to face each other at the contact holes 24 of the spacer 21.
The third position near the back surface, that is, at a position away from 22, 23
A circuit conductor 25 for mounting the electronic component 8 is provided on the layered electrode sheet 20, and above the circuit conductor 25, the electrode sheet 20 and the spacer 21 are penetrated to the surface of the circuit board 30. The electronic component storage hole 26 is formed, and the electronic component 8 is stored and arranged in the electronic component storage hole 26. In the above case, the electrode sheet 20 is made of one sheet, as shown in the development view of FIG. 2, and is provided with the tail portion T in a state of being narrowed and projected so as to extend a part thereof. At the same time, the wires extended from the tail portion T are sequentially mounted in a distributed manner at four portions W to Z.
That is, the via wiring 27 is mounted from the area W adjacent to the tail portion T to the second area X, the third area Y, and the fourth area Z, and is electrically connected. , The second to fourth areas X to Z are provided with the electronic component storage holes 26, respectively. Third
A plurality of lower contact electrodes 22 are provided in the fourth area Y, and a plurality of upper contact electrodes 23 are aligned in the fourth area Z in correspondence with the lower contact electrodes 22. It is provided. That is, the electrode sheet 20 is used in each area W
Bent positions A-A, BB, C between each of Z to Z
It has a multilayer structure as shown in FIG. 1 in which the spacers 21 are interposed between each of them, and the thickness of the electronic component 8 is about 1 to 1.5 m.
It is thicker than m, and the electronic components 8 are arranged so as to pass through the electronic component storage holes 26 so as to face the surfaces,
Contact holes 22 provided on the spacer 21 for the contact electrodes 22 and 23
They are facing each other. And circuit board
A surface decorative sheet 28 is attached to the surface of 30 so that the surface decorative sheet 28 forms an operation surface. Thus, in the membrane switch of this embodiment, the circuit board 30 is formed by folding the electrode sheet 20 and interposing the spacers 21 between the folding,
Since a thickness corresponding to the height of the electronic component 8 is secured, when the electronic component 8 is housed in the circuit board 30 in a state of penetrating the electronic component housing hole 26, the electronic component 8 is on the surface of the circuit board 30. The surface decorative sheet 28 can be formed flat without protruding to the outside. Further, since the circuit board 30 has a multi-layered structure, the contact electrodes 22, 23, the circuit wirings for the contact electrodes 22, 23, the circuit wirings for the electronic component 8 and the like are distributed in different layers. As a result, the circuit wirings can be prevented from becoming complicated without the circuit wirings crossing over. Although the circuit board 30 has a three-layer structure in the above embodiment, it may have a multi-layer structure having more layers depending on the height of the electronic component 8 to be mounted. [Effects of the Invention] As described above, the membrane switch according to the present invention can exhibit the following effects. (1) Since a plurality of electrode sheets are folded over to form a multilayer circuit board, the height of the electronic component can be allowed depending on the thickness thereof, and the electronic component storage hole is formed in the circuit board. By accommodating the electronic component by storing the electronic component, it is possible to prevent the electronic component from projecting to the surface of the circuit board and form the surface portion flat. Therefore, unlike the prior art, it is not necessary to perform uneven processing on the surface portion using an expensive mold, and the cost can be reduced. Further, since the spacer is interposed between the folded electrode sheets, the folded portion of the electrode sheet can be folded with a bending radius of a predetermined value or more,
Therefore, the electrode sheet is not damaged by folding. (2) Contact electrodes near the surface of the multilayer circuit board,
Since the circuit conductors related to the electronic component are arranged near the back surface, the circuit wiring related to the electronic component and the circuit wiring related to the contact electrode are distributed in different layers to reduce the complexity of the circuit wiring. You can

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front sectional view showing an embodiment of a membrane switch according to the present invention, FIG. 2 is a development view of an electrode sheet portion in the embodiment, and FIG. 3 is a conventional membrane switch. FIG. 4 is a front sectional view showing a structural example, and FIG. 4 is a plan view of a base sheet in the conventional example. 8 ... Electronic components, 20 ... Electrode sheet, 21 ... Spacers, 22,23 ... Contact electrodes, 24 ... Contact holes, 25 ... Circuit conductor, 26 ... Electronic component storage holes, 27 ... Via wiring, 28 …… Surface decorative sheet, 30 …… Circuit board, T …… Tail part, AA ・ B ・ B ・ C ・ C …… Bending position, W …… First area, X …… 2nd area, Y ... 3rd area, Z ... 4th area.

Claims (1)

(57) [Claims] Flexible electrode sheet having a rectangular shape as a whole (20)
In a circuit board (30) having a multi-layer structure formed by folding a plurality of layers through a bending line parallel to the edge, a spacer (21) is interposed between the folded electrode sheets,
An electronic component storage hole (2) for storing an electronic component (8) that is mounted on the electrode sheet and protrudes from the surface of the electrode sheet and penetrates through the overlapping positions of the electrode sheet and the spacer.
Membrane switch characterized by having 6).