KR100324780B1 - Key switch - Google Patents

Abstract

An object of the present invention is to provide a key switch having a high degree of freedom of display printing on a key top and a reliable switching operation of a contact point.

An upper sheet (3) mounted on the lower substrate (1) on which the central fixed contact point (6) and the peripheral fixed contact point (7) are mounted and made of a light diffusing material on the lower board (1) (3) ) Is laminated and integrated. Bond the top of the tact spring 2 functioning as a movable contact to the lower surface of the top sheet 3 and always contact the periphery of the tact spring 2 to the peripheral stationary contact 7 and at the same time the top of the center stationary contact. It is separated from (6) at predetermined intervals. The projection 8 is formed on the upper surface of the upper sheet 3 and the position of the projection 8 is coincident with the top of the tact spring 2. When the display portion is printed on the flat bottom of the key top 4 formed of a transparent material and the upper surface of the key top 4 is pressed, this pressing force is applied to the tact spring through the protrusion 8 and the top sheet 3. By transmitting to the top of (2), the tact spring 2 is buckled and brought into contact with the central fixed contact 6.

Description

Key switch {KEY SWITCH}

The present invention relates to a key switch for switching a contact by pressing a key top.

The key switch is used in an input device such as a cellular phone or an acoustic device, and is roughly composed of a switch unit section for switching contacts and a key top for operating the switch unit section.

Conventionally, as such a key switch, a switch unit portion is formed by stacking and integrating a lower substrate provided with a fixed contact and a bowl-shaped tact spring using a sheet member or the like, and a key top for an external case into which the switch unit portion is fitted. It is proposed to support this. The tact spring functions as a movable contact, and the tact spring is in contact with and separated from the fixed contact, thereby switching ON / OFF. In addition, the key top is printed with display parts such as numerals and letters indicating the function contents, and a projection for pressing the top of the tact spring is integrally formed at the center of the bottom of the key top.

In the key switch configured as described above, when the user presses the upper surface of the key top, the pressing force is transmitted to the top of the tact spring through the projection of the bottom of the key top, so that the tact spring is buckled with a click feeling. It is inverted and brought into a switched-on state by contacting the stationary contact. Further, when the pressing force to the key top is removed, the tact spring is returned to the bowl shape by its elasticity, so that the key top returns to the initial position and is switched off.

By the way, the display portion of the key top may be printed on the upper surface and the bottom surface. In the dimming type key switch, the display portion is printed on the bottom surface of the key top formed of transparent material, and the display is performed at night or the like. The structure which recognizes a display part by irradiating light from the said light source to the bottom face of a key top by lighting a light source, such as an LED, in the inside of a place.

However, in the above-described conventional key switch, since projections for pressing the top of the tact spring are integrally formed on the bottom of the key top, a flat printing surface cannot be secured on the bottom of the key top, and the printing area of the display portion is large. There is a problem of being removed. In this case, it is also conceivable to print the display portion on the upper surface of the key top, but since the upper surface of the key top is a part directly touched by the user, the display portion is peeled off by repeated use. Further, in the above-described conventional key switch, since the switch unit portion and the key top are positioned through an external case or the like, projections of the key top are caused at the top of the tact spring due to dimensional or assembly errors of the respective members. There is also a problem that a positional deviation occurs with respect to this, which deteriorates the operation feeling of the tact spring or the switching operation of the contact is uncertain.

1 is a cross-sectional view of a key switch according to an embodiment of the present invention.

2 is a plan view of a top sheet provided in the key switch.

Explanatory drawing which shows the modification of a processus | protrusion.

4 is an explanatory diagram showing a modification of the movable contact;

* Description of the symbols for the main parts of the drawings *

1: lower substrate 2: tact spring

3: top sheet 3a: ridge

4: key top 5: LED

6: center fixed contact 7: peripheral fixed contact

8, 11: protrusion 9: frame

10: exterior case 10a: guide hole

12: movable contact

The present invention is to integrally install the movable contact on the lower surface of the upper sheet and to form a projection on the upper sheet for transmitting the pressing force from the key top to the movable contact. If projections are formed on the upper sheet in which the movable contact is integrated in this way, a flat printing surface can be secured on the bottom of the key top, and the pressing force from the key top can be applied even if there is a positional deviation between the key top and the movable contact. Can certainly deliver to.

The key switch of the present invention includes a lower substrate having a fixed contact, an upper sheet integrated with the lower substrate, a movable contact integrally provided on a lower surface of the upper sheet and opposed to the fixed contact at a predetermined interval, A key top for contacting and disconnecting the movable contact with respect to the fixed contact, forming a projection at a position corresponding to the movable contact of the upper sheet, and a pressing force from the key top causes the movable contact to pass through the projection. It is configured to be delivered to.

The protrusions may be formed on any of the upper and lower surfaces of the top sheet, and when forming the protrusions on the upper surface of the top sheet, a part of the top sheet may be raised by embossing or the like, but the urethane resin or epoxy resin may be formed on the top sheet. It is suitable to print on. In addition, the adhesive printed on the lower surface of the upper sheet may be turned. In this case, a bowl-shaped tact spring may be used as the movable contact, and the tact spring may be attached to the lower surface of the upper sheet by turning.

Although the material of the top sheet is not particularly limited, the top sheet made of a light diffusing material can be used to diffuse light from the light source in the top sheet and irradiate the bottom surface of the key top to a dimming type key switch. Fit.

1 is a cross-sectional view of a key switch according to an embodiment of the present invention, Figure 2 is a plan view of a top sheet provided in the key switch. The key switch according to the embodiment is used as an operation panel of a cellular phone, and the like, as shown in FIG. 1, the lower substrate 1, the upper sheet 3 to which the tact spring 2 is adhered to the lower surface, and the tact spring. It is outlined by the key top 4 for driving (2).

On the surface of the lower substrate 1, an LED 5 as a light source is mounted, and a central fixed contact 6 and a peripheral fixed contact 7 surrounding it are provided. In FIG. 1, only a pair of central fixed contacts 6 and peripheral fixed contacts 7 are shown, but in the embodiment, a plurality of pairs of central fixed contacts 6 and peripheral fixed contacts 7 are arranged in a matrix.

The tact spring 2 functions as a movable contact, and is formed by forming a metal spring material such as phosphor bronze into a bowl shape. The periphery of the tact spring 2 is always in contact with the peripheral fixed contact 7, but its top part is spaced apart from the central fixed contact 6 at a predetermined distance. The top of the tact spring 2 is adhered to the lower surface of the top sheet 3, and in this embodiment a plurality of tact springs 2 are arranged in accordance with the arrangement of the central fixed contact 6 and the peripheral fixed contact 7. It is provided in matrix form on the lower surface of (3).

The top sheet 3 is made of a light diffusing material such as a PET film whose surface is treated like a shell, and has projections 8 formed on its upper surface. The formation position of this projection 8 corresponds to the top of the tact spring 2 bonded to the lower surface of the upper sheet 3, and as shown in FIG. It is formed in matrix form on the upper surface of 3). These projections 8 are formed by, for example, printing urethane-based resin on the upper surface of the upper sheet 3, and can achieve uniform projection amounts in accordance with the printing technique. In addition, the periphery of the upper sheet 3 and the lower substrate 1 are integrated into the frame 9 by using an adhesive or the like, and each of these members comprises a switch unit portion.

The key top 4 is molded from a transparent material such as an acrylic resin, and printing portions (not shown) such as numbers and letters are formed on the flat bottom surface thereof. The upper part of the key top 4 protrudes from the guide hole 10a of the exterior case 10, and the exterior case 10 is being fixed to the frame 9 using screw fixing, an adhesive agent, etc. The bottom face of the key top 4 opposes the projection 8 of the top sheet 3, and therefore, in the embodiment, a plurality of key tops 4 are arranged in a matrix in the outer case 10.

Since the key switch configured as described above presses the upper surface of the key top 4 desired by the user, the pressing force is transmitted to the top part of the lower tact spring 2 via the projection 8 and the upper seat 3, When the key top 4 is lowered by a predetermined stroke, the corresponding tact spring 2 is buckled and inverted with a click feeling, and the top part of the tact spring 2 comes into contact with the center fixed contact 6 to be switched on. . At this time, even if the relative positions of the key tops 4 and the switch unit portions are slightly shifted due to dimensional or assembly errors of the respective members, the protrusions 8 and the upper sheets (printed) formed on the upper surface of the upper sheet 3 ( Since the relative position of the tact spring 2 adhere | attached to the lower surface of 3) is maintained with high precision, the operation feeling of the tact spring 2 does not worsen. And when the pressing force to the key top 4 is removed, since the tact spring 2 returns to the bowl shape by its elasticity, the top sheet 3 and the key top 4 are returned to the initial position accordingly. Is switched off. In addition, when the LED 5 is turned on in a dark place such as at night, since the light emitted from the LED 5 is diffused in the upper sheet 3 and irradiated with almost uniform brightness to the bottom of the key top 4, The display portion printed on the bottom surface of the transparent key top 4 is dimmed with uniform and sufficient brightness, and the display portion can be clearly recognized by passing through the key top 4.

In the embodiment shown in FIG. 3, an adhesive is printed on the lower surface of the upper sheet 3 to form a projection 11, and the top of the tact spring 2 is bonded to the projection 11. In this case, the projection 11 has a function of transmitting the pressing force of the key top 4 to the tact spring 2 and a function of adhering the tact spring 2 to the upper sheet 3.

In the embodiment shown in FIG. 4, the ridge portion 3a is formed on the upper sheet 3 by embossing, and the conductive ink as the movable contact 12 is formed on the lower surface of the ridge portion 3a. At the same time, the projection 8 is formed at the top of the upper surface of the ridge 3a. In this case, the ridge 3a and the movable contact 12 achieve the same function as the above-described tact spring 2, and the ridge 3a is buckled with the pressing of the key top 4 to generate a feeling of click. .

In addition, in the embodiment shown in Fig. 4, when the click feeling is not required, the flat upper sheet 3 without the ridge 3a, as shown in the conventional membrane switch, is provided with the lower substrate 1 through the spacer. What is necessary is just to form the processus | protrusion 8 in the upper surface of the upper sheet 3 corresponding to the movable contact 12 by laminating | stacking on it, and also can use a film material as the lower substrate 1. As shown in FIG.

The present invention is carried out in the form described above and exhibits the effects as described below.

A lower substrate having a fixed contact, an upper sheet integrated with the lower substrate, a movable contact integrally provided on a lower surface of the upper sheet and opposed to the fixed contact at a predetermined interval, and fixing the movable contact. And a key top for contacting and separating the contact, forming a protrusion at a position corresponding to the movable contact of the upper sheet, and configured to transmit a pressing force from the key top to the movable contact through the protrusion. In addition, it is possible to secure a flat printing surface on the bottom of the key top, and to securely transmit the pressing force from the key top to the movable contact even if there is a positional deviation between the key top and the movable contact.

In addition, when the light diffusing material is used as the top sheet, the light from the light source can be diffused in the top sheet and irradiated to the bottom of the key top, which makes it suitable for a dimming type key switch.

Claims (4)

A lower substrate having a fixed contact, an upper sheet integrated with the lower substrate, integrally installed on a lower surface of the upper sheet and opposed to the fixed contact at a predetermined interval and pressed by a key top. A movable contact having a reversing spring in which is inverted to be brought into contact with the fixed contact, and a key top which is formed separately from the movable contact to contact and disconnect the movable contact with the fixed contact, And a projection of the upper sheet formed at a position corresponding to the government of the movable contact, and the pressing force from the key top is transmitted to the movable contact through the projection. The key switch as claimed in claim 1, wherein the protrusion is formed of a resin that is formed on an upper surface of the top sheet. The key switch according to claim 1, wherein the protrusion is made of an adhesive formed on a lower surface of the upper sheet and the movable contact made of a bowl-shaped tact spring is attached to the protrusion. The key switch according to any one of claims 1 to 3, wherein the top sheet is made of a light diffusing material.