KR19990023949A - Illuminated Pushbutton Switches - Google Patents

Abstract

It is desirable to provide a dimmed pushbutton switch that is desirable for promoting thinness and low cost.

The first sheet layer 3 on which the acrylic key top 1 is integrated on the surface of the PET film 2 and the display portion 10 is formed on the bottom surface of the key top 1 and the light diffusion function are provided. The projections 5 are formed on both front and back surfaces of the PET film 4 to have, and the projections 5 are disposed opposite to the rear surface of the PET film 2 so that the projections 5 are located at portions corresponding to the central portion of the key top 1. The 2nd sheet layer 6 and LED7 which irradiates light from the opposite side to the 1st sheet layer 3 side with respect to this 2nd sheet layer 6 are mounted, and the projection part 5 is large, The circuit board 9 on which the tact switch 8 which is push-driven to the said projection part 5 is mounted was attached to the frame 11, and was integrally formed.

Description

Illuminated Pushbutton Switches

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminated pushbutton switch that is capable of dimming a key top in the dark and suitable for use in various electronic devices such as mobile phones.

In recent years, mobile phones, etc., which are rapidly expanding, are required to be clearly identified by the user in key places where numbers and letters are illustrated, such as at night. Pushbutton switches capable of dimming with light from a light source such as a diode) have been widely adopted.

In the prior art of such an illuminated pushbutton switch, a key for which an acrylic key top is bonded to a surface of a silicon rubber and a switching layer such as a membrane switch with a click means on a circuit board on which an LED or a connector is mounted. The structure which laminated | stacked the sheet layer sequentially was mainstream, and the display part which shows the operation content of the key top is formed in the bottom surface of an acrylic key top. That is, in the conventional operation panel provided with a plurality of illuminated pushbutton switches, when the user presses a desired key top, the silicon rubber of the branch is bent around the key top so that the membrane switch on the lower side is driven with a click feeling. When the LED is turned on, the light is irradiated to the silicon rubber through the opening of the switching layer, so that light diffused into the milky white silicon rubber is irradiated to each display part of the key sheet layer, so that the bottom of each colorless and transparent key top is In terms of numbers, numerals and letters indicating the contents of each operation are illuminated.

However, the above-described prior art has a configuration in which a silicon rubber having a thickness sufficient to perform a light diffusion function and a switching layer such as a folded membrane switch are interposed between the key top and the circuit board. There has been a problem that promotion of thinning, which is desired on the back, is not well accomplished. In addition, since the light of the LED is irradiated to the silicon rubber through the opening of the switching layer, there is a lot of light that is blocked by the switching layer and is not effectively used, so that sufficient brightness can be obtained without increasing the number of LEDs. There was no. That is, since a large number of LEDs are required as the light source for dimming, and the component cost of the silicon rubber is also relatively high, the prior art described above has a problem that the cost of components increases, which is disadvantageous in promoting the reduction in cost.

According to the present invention, a light diffusion sheet is sandwiched between a light-transmitting sheet in which a key top is integrated and a circuit board on which a light source or a switch element is mounted, and projections corresponding to the key top and the switch element on both front and back surfaces of the light diffusion sheet, respectively. It shall be formed. According to the dimmed pushbutton switch configured as described above, inexpensive and thin films such as PET can be used for each sheet material, so that a thinned structure close to the key top and the circuit board can be adopted. have.

1 is an exploded perspective view of a pushbutton switch group according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the pushbutton switch group shown in FIG. 1 after assembly. FIG.

Explanation of symbols for main parts of drawings

1: key top 2, 4: PET film (sheet material)

3: first sheet layer 5: protrusion

6: second sheet layer 7: LED (light source)

8: Tact switch (switch element) 9: Circuit board

10: display unit 11: frame

The illuminated pushbutton switch of the present invention includes a first sheet layer in which a transparent key top is integrated on the surface of the transparent sheet material, and a display portion is formed in a portion of the key top, and a transparent sheet having a light diffusing function. Projections formed on both front and back surfaces of the ash, and a light source for irradiating light from the side opposite to the first sheet layer to the second sheet layer and the second sheet layer disposed opposite to the back surface of the sheet material of the first sheet layer; And a circuit board on which a switch element driven by the pressing force from the key top is mounted, wherein the protrusion is located at a portion corresponding to the key top and the switch element, respectively.

The first sheet layer can be configured by integrating a translucent key top made of acryl or the like on the surface of a translucent sheet material made of PET or the like by bonding or an insert molding technique.

In addition, the display unit shows the operation contents of key tops such as numbers and letters, and can be printed on the bottom surface or ceiling surface of the corresponding key top or on the surface or back surface of the sheet material of the first sheet layer.

In addition, the second sheet layer functions as a light diffusion sheet, and can be provided with a light diffusion function by embossing the surface of the sheet material or by using a milky white material.

The protrusion may be formed by expanding the sheet material itself of the second sheet layer by embossing or the like. However, when the epoxy resin or the like is formed on both front and back surfaces of the sheet material, the hardness and height required for the protrusion are secured. It is preferable to.

In addition to the above-described configuration, if the second sheet layer covers the surface of the circuit board, the space where the electric circuit of the circuit board is exposed can be sealed, so that the dustproof and waterproof structure can be realized at low cost.

Example

1 is an exploded perspective view of a pushbutton switch group according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the pushbutton switch group shown in FIG. 1 after assembly.

The illuminated pushbutton switch group shown in Figs. 1 and 2 is used as an operation panel of a mobile telephone, and is arranged on a surface of a PET film 2 by arranging a plurality of acrylic colorless or colored transparent key tops 1 in a vertical and horizontal direction. And the second sheet layer 6 formed by forming a plurality of colorless or colored transparent projections 5 on both front and back surfaces of the PET film 4 whose surface is embossed. The circuit board 9 includes a LED 7, a plurality of tact switches 8, a connector (not shown), and the like, and is soldered and outlined.

In the first sheet layer 3, a display portion 10 (see Fig. 2) such as numerals or letters indicating the operation contents of the key top 1 is formed on the bottom surface of each key top 1. However, this display part 10 can also be provided in the surface, the back surface, or the ceiling surface of the key top 1 as long as it corresponds to the formation part of the key top 1. In addition, in this embodiment, the case where each key top 1 is bonded to the PET film 2 is illustrated, but a plurality of key tops may be injection molded on the PET film by using an insert molding technique.

In addition, the 2nd sheet layer 6 is arrange | positioned facing the back surface of the PET film 2 of the 1st sheet layer 3, and each protrusion part 5 in the part corresponding to the center part of each key top 1 is carried out. Is supposed to be located. In this embodiment, an epoxy resin is used as the material of the projections 5, and the printing method for the PET film 2 is adopted as its formation method. However, the same projection may be formed by screen printing or embossing.

And the circuit board 9 is arrange | positioned facing the back surface of the PET film 4 of the 2nd sheet layer 6, and each protrusion part 5 and each tact which protruded in the back surface of the said film 4 are each. By opposing the ceiling surface center of the switch 8, the arbitrary tact switch 8 can be push-driven by the projection 5 above it.

As shown in Fig. 2, the first sheet layer 3, the second sheet layer 6, and the circuit board 9 are integrated using a frame 11 made of a flexible elastomer or a rigid resin higher than that. At the time of such mounting, the edge portion of the PET film 2 of the first sheet layer 3 is applied to only the rear surface thereof and adhered to and fixed to the frame 11, but the PET film of the second sheet layer 6 ( 4) An adhesive is applied to both sides of the front and back over the entire circumference of the branch, and is bonded and fixed to both the frame 11 and the circuit board 9.

In the illuminated pushbutton switch group configured as described above, when the user presses the desired key top 1, the key top 1 presses the lower protrusion 5 so that the key top 1 is lowered by a predetermined stroke. At the time point, the corresponding tact switch 8 is push driven with a click feeling. At this time, the PET films 2 and 4 are bent locally, but since the bending is eliminated with excellent restoring force when the pressing operation force is removed, the lowered key top 1 and the protrusion 5 quickly return to their original height positions. Return to In addition, the illuminated pushbutton switch group includes a PET film having a light diffusing function that emits light emitted from a plurality of LEDs 7 mounted in a region where the tact switch 8 of the circuit board 9 does not exist. 4) can be irradiated from the back side, and when each LED 7 is turned on in a dark place such as at night, the light diffused to the PET film 4 is approximately equal to the entire surface of the PET film 2. Irradiated with brightness. As a result, the display portions 10, such as numbers or letters, printed on the bottom surface of each colorless or colored transparent key top 1 are uniformly and dimmed with sufficient brightness, so that the user can clearly check each display portion 10. It is.

Moreover, this illuminated pushbutton switch group is a sheet material interposed between the key top 1 group and the circuit board 9, and because it uses inexpensive and very thin PET films 2 and 4, the thickness and cost are reduced. Savings are realized.

The illuminated pushbutton switch group is attached to the frame 11 to form an integrated product, but the PET film 4 of the second sheet layer 6 has both front and back sides of the frame over its entire circumference. Since it is adhered and fixed to both the 11 and the circuit board 9, not only can the circuit board 9 be fixed to the frame 11 via the PET film 4, but also the electrical of the circuit board 9 can be fixed. The space 12 in which the circuit is exposed can be sealed with the PET film 4, and a highly reliable dustproof waterproof structure can be obtained.

In addition, in the above-described embodiment, the case where the PET films 2 and 4 are used as the sheet material of the first and second sheet layers 3 and 6 has been described. You may use the sheet material which consists of materials. Further, the key top 1 may also be formed of a material other than acrylic as long as it can secure light transmittance corresponding to colorless or colored transparency.

This invention is implemented in the form as described above, and has the effect as described below.

The translucent key top is integrated on the surface of the translucent sheet material, and the protrusions are formed on both front and back surfaces of the first sheet layer having the display portion formed on the mounting portion of the key top, and the translucent sheet material having the light diffusing function. The second sheet layer disposed opposite to the back surface of the sheet material of the first sheet layer, the light source irradiating light from the side opposite to the first sheet layer side to the second sheet layer, and the pressing force from the key top is received. If a circuit board is provided with a switch element to be driven, and the protrusion is positioned at a portion corresponding to the key top and the switch element, the sheet material of the first and second sheet layers may be inexpensive. Since a thin film can be used, it is possible to provide a lighted pushbutton switch which is inexpensive and desirable for thinning.

In addition, when the second sheet layer is configured to cover the surface of the circuit board, the space where the electric circuit of the circuit board is exposed can be sealed, so that the dustproof and waterproof structure can be realized at low cost.

Claims (3)

A first sheet layer in which a light-transmissive key top is integrated on the surface of the light-transmitting sheet material, and a display portion is formed in a formation portion of the key top; Projections are formed on both front and back surfaces of the light-transmitting sheet material having a light diffusing function, and the second sheet layer is disposed opposite to the rear surface of the sheet material of the first sheet layer; And a circuit board mounted with a light source for irradiating light from the side opposite to the first sheet layer with respect to the second sheet layer, and a switch element driven by a pressing force from the key top, wherein the protrusion is provided with the key top. And a push button switch, each of which is located at a portion corresponding to the switch element. The illuminated pushbutton switch of claim 1, wherein the second sheet layer covers a surface of the circuit board. The illuminated pushbutton switch according to claim 1 or 2, wherein the projection is formed on both sides of the sheet material of the second sheet layer.