JPH06203698A - Switch for circuit board - Google Patents

Abstract

PURPOSE:To lower the cost of a switch for a circuit board by simplifying the manufacturing processes and at the same time improve the click touch at the time of pushing a letter panel and moreover improve the durability of the switch. CONSTITUTION:A switch is installed on a film substrate 10 and a front side circuit 11 and the rear side circuit 12 of the film substrate are communicated with each other by the switch. The switch is composed of a through hole contact 14 which penetrates the film substrate 10 from the rear side circuit 12 and is formed on the front side, a circular contact 15 of the front side circuit 11 which is formed in the way it surrounds the through hole contact 14, and an elastic metal plate 16 having a dome-like shape whose outer circumfenence is positioned on the circular contact 15 and which covers the through hole contact 14. The through hole contact 14 and the circular contact 15 are brought into contact with each other by pushing and deforming the metal plate 16 elastically and thus both are communicated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board switch for switching an internal electronic circuit when a character panel such as a card type calculator or an electronic notebook is pressed.

[0002]

2. Description of the Related Art A flexible film substrate 1 on which a printed circuit is formed is arranged inside a card type calculator as shown in FIG. 6, and a character panel of the card type calculator is placed on the film substrate 1. A switch 3 corresponding to each character portion arranged in 2 is mounted. When the character panel 2 is pressed, the switch 3 located below the pressed character is pressed and turned on to switch the electronic circuit.

By the way, as a conventional circuit board switch, for example, one having a structure as shown in FIG. 7 is known. This is a circuit board composed of a sandwich structure of a pair of upper and lower film substrates 1a and 1b and an insulating film 4 disposed between them, and each of the film substrates 1a and 1b has a surface facing each other. A printed circuit is formed. Further, through holes 5 are provided in the insulating film 4 at positions corresponding to respective characters of the character panel 2, and the film substrates 1 are provided above and below the through holes 5.
The contacts 6a and 6b of the printed circuits formed on a and 1b are spaced apart and face each other. Furthermore, the upper film substrate 1a
It has a structure in which a plastic film 8 having a dome-shaped embossed portion 7 formed on the upper portion is covered with the portions corresponding to the contacts 6a and 6b. The embossing section 7 is provided in order to make the fingertip feel a click feeling that a predetermined character is surely pressed when each character of the character panel 2 is pressed.

Therefore, in the circuit board switch having such a structure, when each character of the character panel 2 is pressed, the embossed portion 7 of the plastic film 8 located therebelow is pressed and recessed, and further at that position. Embossed part 7
Is warped, the upper film substrate 1a is pushed, the upper contact 6a contacts the lower contact 6b, and the circuit becomes conductive. When the finger is released from the character panel 2, the upper film substrate 1a is restored and the contacts 6a and 6b are separated from each other, and the embossed portion 7 of the plastic film 8 is also restored to return to the original state shown in FIG.

[0005]

By the way, there is a problem that the circuit board switch having the above-mentioned configuration is constructed after undergoing a number of manufacturing steps as shown in FIG. That is, first, a circuit including the contacts 6b is printed on the lower film substrate 1b (first step), and then the film substrate 1b is printed.
The outer shape of b is adjusted (second step), and the insulating film 4
A through hole 5 corresponding to the position of the contact 6b is opened (third step), and the insulating film 4 is attached to the lower film substrate 1b (fourth step). Further upper film substrate 1
A circuit including the contact 6a is also printed on a (fifth step), and the outer shape of the film substrate 1a is cut according to the lower substrate 1b (sixth step). Then, the upper film substrate 1a is further laminated and attached on the insulating film 4 attached on the lower film substrate 1b (seventh step). Finally, the plastic film 8 having the embossed portion 7 is attached onto the upper film substrate 1a (eighth step), and all steps are completed. As described above, when manufacturing a conventional circuit board switch, a large number of steps are required, which causes a problem of increased manufacturing cost. Further, there is a problem that the product yield is reduced due to the large number of manufacturing steps.

Further, in the above-mentioned conventional circuit board switch, the dome-shaped embossed portion 7 is provided on the plastic film 8 in order to give a click feeling when a character is pressed, but this is for a long time. When used for a long time, the resilience of the embossed portion 7 decreases, making it difficult to obtain a good click feeling, and there is a problem in terms of durability.

[0007]

Therefore, the present invention simplifies the manufacturing process of the switch for circuit board to reduce the cost, improves the feeling of clicking when the character panel is pressed, and further improves the durability of the switch. The purpose is to improve the sex.

That is, the circuit board switch according to the present invention is a switch which is provided on the circuit board and electrically connects the front surface side circuit and the back surface side circuit of the circuit board. A through hole contact penetratingly formed on the front surface side, a peripheral contact of the front surface side circuit formed so as to surround the through hole contact, and an outer peripheral edge located on the peripheral contact and above the through hole contact. It is characterized by comprising a substantially dome-shaped elastic metal plate which covers the through hole contact and the peripheral contact by elastically pressing and deforming the metal plate so as to conduct the both.

[0009]

According to the above-mentioned means, when the dome-shaped metal plate is pushed from above, the metal plate warps back in a curved shape and comes into contact with both the through-hole contact and the peripheral contact. Therefore, the through hole contact and the peripheral contact are connected through the metal plate, and the front surface side circuit and the back surface side circuit are electrically connected. When the pressing force on the metal plate is released, the elastic force causes the metal plate to return to the original dome shape.

[0010]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. 1 and 2 show an embodiment of a circuit board switch according to the present invention. Unlike the conventional example, the circuit board in this embodiment is composed of one flexible film substrate 10, and circuits 11 and 12 are printed on both front and back surfaces of this film substrate 10. Further, through-holes 13 penetrating the film substrate 10 from the back-side circuit 12 are formed in the switch-corresponding portions of the circuits 11 and 12, and through-hole contacts 14 are provided on the front surface side of the film substrate 10. As shown in FIG. 2, around the through-hole contact 14,
A circumferential contact 15 extending from the front side circuit 11 of the film substrate 10 surrounds it.

Further, in this embodiment, an elastic metal plate 16 is arranged so as to cover the through hole contact 14 and the circumferential contact 15 above. This metal plate 16
2 has a so-called dome shape in which a part of a hemisphere is cut as shown in FIG.
As shown in FIG. 5, the circular contact 15 has a circular shape, and the diameter of the circular contact 15 substantially corresponds to the diameter of the circular contact 15. The metal plate 16 is made of a thin plate material having a spring characteristic such as phosphor bronze. When the top of the dome is pushed by a finger, the metal plate 16 is bent back to the opposite side and elastically deformed into a curved shape. It returns to its original dome shape due to the restoring force of bronze. Although the curvature of the metal plate 16 is not particularly determined, it is necessary that at least the through-hole contact 14 does not contact the inside of the dome when placed on the circumferential contact 15, as shown in FIG.

Further, the outer peripheral edge of the metal plate 16 is shown in FIG.
As shown in, the horizontal grounding portion 17 is formed with a very narrow width. The ground portion 17 prevents the printed circuit from being damaged by making surface contact with the circumferential contact 15. Furthermore,
In this embodiment, a straight portion 18 having no curvature is formed at the rising portion of the dome from the ground contact portion 17 with a predetermined width over the entire circumference. This straight portion 18 is shown in FIG.
As shown in FIG. 5, the boundary with the curvature portion has a wide angle α ° of 180 ° or less. As a result, when the dome top of the metal plate 16 is pressed with a finger, it is possible to reliably prevent the metal plate 16 from remaining in a warped state without being restored. That is, the wide angle α ° is 180 ° even when the metal plate 16 is pushed by a finger and the dome portion is warped.
Since the metal plate 16 does not spread as described above, when the finger is released from the metal plate 16, the metal plate 16 easily returns to the original state due to elastic return. Therefore, it is possible to reliably prevent the metal plate 16 from being in a warped state without being restored. The angle β ° of the straight portion 18 with respect to the horizontal plane 21 and the width dimension W of the straight portion 18 are not particularly limited, but a good click feeling when pressed with a finger and a reliable click feeling when the finger is released. In order to obtain the restoration stably over a long period of time, the angle β ° of the straight portion 18 is set within a range of about 5 to 20 ° with respect to the horizontal plane 21, and the width dimension W of the straight portion 18 is set to that of the metal plate 16. It is desirable to set within the range of 10 to 20% of the radius.

Further, in this embodiment, a small circular hole 22 is formed in the substantially central portion of the metal plate 16. This circular hole 22
Is for releasing the stress concentrated in the central portion of the dome when the metal plate 16 is pushed and bent back, and thereby the durability of the metal plate 16 can be greatly improved. The diameter of the circular hole 22 is not particularly limited, but is preferably about 10 to 20% of the diameter of the metal plate 16.

Next, a manufacturing process of the circuit board switch having the above structure will be described with reference to FIG. First, the front surface side circuit 11 is printed on the upper surface of the flexible film substrate 10 (first step). At this time, the through-hole contact 14 and the circumferential contact 15 are simultaneously printed. Next, the through holes 13 are formed in the film substrate 10 (second step).
Further, the back side circuit 12 is printed on the film substrate 10, and at the same time, the through hole contact 1 is formed through the through hole 13.
4 is also connected (third step). In the next step, the film substrate 10 is cut into a predetermined outer shape (fourth step). Then, finally, the outer peripheral edge of the metal plate 16 is aligned and placed on the circumferential contact 15 formed on the front surface side circuit 11 of the film substrate 10, and the adhesive tape 19 fixes the metal plate 16 on the outer periphery. 5 steps). As described above, the circuit board switch according to the present embodiment can be manufactured by the fifth step, and the number of steps is significantly reduced as compared with the conventional switch that requires the eighth step. be able to.

Next, the operation of the circuit board switch having the above structure will be described with reference to FIGS. For example, when the film substrate 10 is mounted on a card type calculator, the character panel 20 is placed above the film substrate 10 and the metal plate 16
Each character 23 corresponds to the position above. Then, first, when one character 23 on the character panel 20 is pressed with a finger, the corresponding metal plate 16 is also pressed at the same time, the outer peripheral edge grounding portion 17 strongly abuts on the circumferential contact 15, and the central portion is curved. It bends back and contacts the through-hole contact 14. As a result, the circumferential contacts 15 and the through-hole contacts 14 are conducted through the metal plate 16, and the circuit is switched. When the finger is removed from the character panel 20, the metal plate 16 returns from the warped state due to the restoring force to the original dome shape and is separated from the through hole contact 14.

As described above, since the circuit board switch according to the present embodiment is constituted by the elastic metal plate 16, it is possible to obtain a good click feeling when the character panel 20 is pushed. In addition, the straight portion 18 is provided on the metal plate 16.
By providing the above, the elastic return of the metal plate 16 can be surely obtained. Further, since the circular hole 22 is formed at the top of the dome, the stress does not concentrate on the center of the metal plate 16 even when the metal plate 16 is pushed and bent back, and the durability of the metal plate 16 is improved.

Although a flexible film substrate is used as the circuit substrate in the above embodiment, a rigid substrate such as an epoxy resin substrate or a phenol resin substrate can be used in the present invention.

Further, although the card type calculator has been described as an example in the above-mentioned embodiments, the present invention can be widely applied to various industrial equipments and consumer equipments using this type of circuit board switch. is there.

[0019]

As described above, according to the circuit board switch of the present invention, the switch itself has a simple structure, so that the number of manufacturing steps is small, the manufacturing cost is reduced, and the manufacturing yield is improved. Can be achieved. Further, according to the circuit board switch of the present invention, since the dome portion for giving the click feeling when the character panel is pressed is made of the elastic metal plate, compared with the conventional plastic constitution. A good click feeling can be obtained for a long period of time.

Further, according to the above-mentioned embodiment, since the straight portion is provided on the outer peripheral portion of the dome of the metal plate, there is an effect that the metal plate can be more reliably restored after being bent back.
By forming a small hole at the top of the dome, it is possible to disperse the stress applied to the top of the dome when the metal plate is warped, and there is an effect that durability is improved accordingly.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a circuit board switch according to the present invention.

FIG. 2 is a plan view of the circuit board switch.

FIG. 3 is an enlarged view of part A of FIG.

FIG. 4 is a manufacturing process diagram of the circuit board switch.

FIG. 5 is an operation diagram of the circuit board switch.

FIG. 6 is a perspective view showing a circuit board of a card type calculator.

FIG. 7 is a cross-sectional view of a conventional circuit board switch.

FIG. 8 is a manufacturing process diagram of the conventional circuit board switch.

[Explanation of symbols]

 10 Film Substrate 11 Front Side Circuit 12 Back Side Circuit 14 Through Hole Contact 15 Circular Contact 16 Metal Plate 18 Straight Part 22 Circular Hole

Claims (3)

[Claims] 1. A switch provided on a circuit board for electrically connecting a front surface side circuit and a back surface side circuit of the circuit board, wherein the switch is formed on the front surface side through the circuit board from the back surface side circuit. A hole contact, a peripheral contact of the surface side circuit formed so as to surround the through hole contact, and a substantially dome-shaped elastic metal plate having an outer peripheral edge located on the peripheral contact and covering the through hole contact. A switch for a circuit board, characterized in that the metal plate is elastically pressed and deformed to make contact with the through-hole contact and the peripheral contact so that both are brought into conduction. 2. The circuit board switch according to claim 1, wherein the metal plate is formed with a straight portion having no curvature at a rising portion from the outer peripheral edge to the dome. 3. The circuit board switch according to claim 1, wherein a small hole is provided at the top of the dome of the metal plate.