JP2578772Y2 - Key top support structure and key switch - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a key switch used as input means for various devices and a key top support structure used for the key switch.

[0002]

2. Description of the Related Art There is an increasing number of devices, such as portable telephones, which are required to be miniaturized and to be usable in dark places outdoors. In such a device, a key switch which is small and has a lighting function is required.
FIG. 6 shows the structure of a conventional key switch of this type. In the figure, reference numeral 1 denotes a key top. The key top 1 is formed of a transparent resin material into, for example, an oval shape or a rectangular shape. 2 indicates a case of the apparatus. The case 2 has a window 2A for exposing the key top 1. Key Top 1
Are adhered to and supported by the rubber sheet 3. The rubber sheet 3 is formed of a material having light transmittance and flexibility, such as silicon rubber. Rubber sheet 3 is spacer part 3
A, a key top support portion 3B, and a light source engaging portion 3C. The spacer portion 3A is configured to have a thickness for keeping a gap between a membrane sheet 4 and the case 2 described later constant. The key top support portion 3B is formed by forming the rubber sheet 3 to be thin, and has a structure that can be greatly elastically deformed by the thinness. The key top 1 is adhered to the upper surface side of the key top support portion 3B to support the key top 1 and form a projection 3D on the back side, and the membrane switch SW provided on the membrane sheet 4 is pressed by the projection 3D. I do.

As is well known, a membrane sheet 4 is formed by laminating film-like sheets 4A and 4B with a spacer 4C interposed therebetween. The spacer 4C has a hole 4D.
The sheets 4A and 4B are arranged so as to face each other at the position, and the electrodes T ₁ and T ₂ are attached to the facing surfaces. These electrodes T ₁ and T ₂ constitute a membrane switch SW.

A printed wiring board 5 is provided on the lower surface side of the membrane sheet 4. The light source 6 is mounted on the printed wiring board 5. The light source 6 has holes 4E formed in the membrane sheet 4.
And its head engages with a light source engaging portion 3C formed on the rubber sheet 3. Light source engaging part 3C is spacer part 3A
Can be formed by forming a concave hole in the lower surface of the. Light source 6
Is transmitted to the key top 1 through the rubber sheet 3 so that the key top 1 is illuminated. On the back of the keytop 1, characters, symbols, figures, and the like representing the functions assigned to each keytop 1 are printed. These characters, symbols, figures, and the like are illuminated with light from the light source 6 so that they can be easily operated even in a dark place.

[0005]

As described above, the conventional key switch has a structure in which a relatively expensive rubber sheet 3 is used as described above, and thus has a disadvantage of increasing costs. Further, since the rubber sheet 3 has flexibility, it is difficult to directly print characters, symbols, figures, and the like for displaying functions on the surface of the key top support 3B. For this reason, characters, symbols, figures, and the like for displaying functions are conventionally printed on the back surface of the key top 1. Since the shape of the key top 1 is small with the miniaturization of the apparatus, there is a disadvantage that printing takes time and effort. In this respect, there is a disadvantage that the manufacturing cost is further increased.

Further, the work of bonding the key top 1 to a predetermined position of the rubber sheet 3 is troublesome. That is, the rubber sheet 3 has a property of being greatly deformed by a small force.
Therefore, when the key top 1 is successively transported to a predetermined position by an automatic machine and is to be bonded, the rubber sheet 3 has a large deformation amount, so that the positional deviation is large and it is difficult to bond the key top 1 to the predetermined position.

The object of the present invention is to provide a key top support structure which can automate the bonding of the key top using inexpensive materials, and which does not require printing for displaying the function on the key top. And a key switch using the key top support structure.

[0008]

In this invention, a key top formed by a transparent flat plate is adhered and supported on a transparent film sheet. In the transparent film sheet, the characters, symbols,
Figures and the like are printed. On the back side of the transparent film sheet, apply a paint such as a white paint to increase the light guide efficiency,
Further, a protrusion is formed by adhering substantially to the center of the key top. A light guide plate composed of a transparent plate is laminated and integrated on the back side of the transparent film sheet. The light guide plate has a hole at a position facing the key top having a shape larger than the planar shape of the key top. Since the transparent film sheet is inserted into the hole and supports the key top on the upper surface, the key top is movably supported by the elasticity of the transparent film sheet.

According to the key top support structure, the key top may be bonded to the transparent film sheet. Since the transparent film sheet does not significantly deform in the expansion and contraction direction, the position where the key top should be adhered can be accurately maintained in a posture where the transparent film sheet is arranged on a plane. As a result, in addition to being able to easily perform printing, the key top can be accurately adhered to a predetermined position on the transparent film sheet by an automatic machine.

Further, printing on a transparent film sheet is easy. Therefore, it is easy to print characters, symbols, figures, and the like for displaying functions, and printing can be performed at low cost. According to the present invention, the membrane sheet is further laminated on the lower surface of the light guide plate, and the membrane switch formed on the membrane sheet by the key top can be operated. That is, a key switch can be configured.

Further, a printed wiring board is laminated on the lower surface of the membrane sheet, a light source is mounted on the printed circuit board, the light source is passed through a hole formed in the membrane sheet, and the light source is engaged with a light source engaging portion formed on the light guide plate. be able to. With this structure, an internally illuminated key switch can be provided.

[0012]

1 and 2 show a key top support structure according to the present invention and a key switch structure using the key top support structure. In FIG. 1, portions corresponding to those in FIG. 6 are denoted by the same reference numerals. In this invention, the key top 1 formed by a transparent plate is bonded to a transparent film sheet 7. As the transparent film sheet 7, for example, an inexpensive film sheet such as a polyester resin can be used. Characters, symbols, figures, and the like indicating functions assigned to the key tops 1 are printed on the transparent film sheet 7 at positions where the key tops 1 are to be bonded. On the back side of the transparent film sheet 7, for example, a white paint having a high light guiding effect is applied or printed. Further, a protrusion 7A is formed facing the center of the key top 1. The protrusion 7A can be formed by, for example, applying a photocurable resin by a printing method or the like.

A light guide plate 8 is laminated on the back surface of the transparent film sheet 7. The light guide plate 8 can be formed of a transparent resin plate having high transparency , such as an acrylic resin plate. The light guide plate 8 is opposed to the key top 1 and has a hole 8A having a shape larger than the planar shape of the key top 1 and a light source 6.
And a light source engaging portion 8B that engages with. By aligning the center of the hole 8A with the center of the key top 1, the key top 1 is elastically supported by the transparent film sheet 7 extended over the hole 8A. The key top 1 can be pushed into the hole 8A. When the pressing force is released, the key top 1 can return to the original position by the restoring force of the transparent film sheet 7.

According to the above-described key top 1 support structure, characters, symbols, figures, and the like representing the functions of the key top 1 can be printed on the transparent film sheet 7. As a result, printing can be easily performed. In addition, the cost can be reduced because of the ease of printing and the use of the inexpensive transparent film sheet 7. The present invention further proposes a key switch using the key top support structure. For this purpose, the membrane sheet 4 is laminated on the lower surface of the light guide plate 8. 1 and 2 show an example in which an embossed sheet 9 is interposed on the upper surface side of the membrane sheet 4. The embossed sheet 9 is formed by forming a dome 9A on a resin plate, and the dome 9A is arranged inside a hole 8A formed in the light guide plate 8. More specifically, the protrusion 7A and the dome 9A formed at the center position of the key top 1 are aligned and arranged. By applying a pressing force to the key top 1, a pressing force is applied to the dome 9A via the protrusion 7A, and the dome 9A is crushed and deformed. When the dome 9A is deformed, a click feeling is given to the finger, and an operation feeling can be given. On the other hand, when the dome 9A is deformed, that is, the dome 9A is deformed downward and gives a downward force to the membrane sheet 4. Consequently contact T ₁ and T ₂ of the membrane switch SW contacts provided on the membrane sheet 4, it transmits a contact signal.

A printed wiring board 5 is arranged on the lower surface side of the membrane sheet 4. A light source 6 is mounted on the printed wiring board 5. As the light source 6, for example, a light emitting diode (LED) can be used. The light source 6 has a head engaged with a light source engaging portion 8B formed on the light guide plate 8 through a through hole 4E formed in the membrane sheet 5. The light from the light source 6 is incident on the key top 1 through the light guide plate 8 and the transparent film sheet 7, and is also illuminated on the hole 8A formed in the light guide plate 8 when illuminating the key top 1 itself. Also illuminate. As a result, characters, symbols, figures, and the like for function display printed on the transparent film sheet 7 are illuminated, and the arrangement of the key top 1 can be read even when it is dark.

FIG. 3 shows a modified embodiment of the present invention. In this example, a case where a metal tact plate 10 is used instead of the dome 9A is shown. In this case, the tact plate 10 is suppressed by the fixing sheet 11. FIG. 4 shows a case where the upper sheet of the membrane sheet 4 is constituted by an emboss sheet 9. That is, the sheet on the upper surface side of the membrane sheet 4 is substituted by the emboss sheet 9. Thus the electrode 9B is formed on the back side of the dome 9A of the embossed sheet 9, the contact point T ₂ and disposed opposite to the electrode 9B, contacting the mutual contact T ₂ by the electrode 9B, thereby transmitting a contact signal Can be done.

Although the contact T ₂ is formed on the insulating sheet 4 B constituting the membrane sheet 4 in the example of FIG. 4, the contacts T ₁ and T ₂ are formed on the printed wiring board 5 as shown in FIG. It is also possible to form such a structure that the contacts T ₁ and T ₂ are brought into contact with each other by the tact plate 10 to transmit a contact signal. In the above embodiment, the key top 1 is used.
Is shown to be exposed from the window of the case 2 to the outside, but the transparent film sheet 7 can be exposed to the outside and mounted on the device.

[0018]

As described above, according to the key-top support structure of the present invention, since the key-top 1 uses the transparent film sheet 7 which can be made of an inexpensive material, the cost can be greatly reduced. . Since characters, symbols, figures, and the like for displaying the functions of the key top 1 are printed on the transparent film sheet 7, the printing can be easily performed. Therefore, in this regard, the manufacturing cost can be reduced.

Further, since the transparent film sheet 7 having no holes is arranged on the entire key board, there is an advantage that the waterproof performance can be improved. Naturally, the transparent film sheet 7
Has no holes, etc., so it is incident on the key top
There is no unevenness in the emitted light. So key
The advantage that the top can be uniformly illuminated is obtained. Furthermore, this
According to the present invention, the transparent material inserted into the hole 8A formed in the light guide plate 8 is provided.
Because the key top is attached to the film sheet 7,
An upward repulsion is evenly applied to the top pressing force.
You. Therefore, there is an advantage that a good operation feeling can be obtained. In addition
The light plate 8 is manufactured simply because the hole 8A is formed.
It can be made easily and inexpensively.
Even in the existing state, there is no part damaged by external force.
The advantage that it can be handled as a highly reliable part
Is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view for explaining the embodiment of FIG. 1 in detail.

FIG. 3 is a sectional view showing a modified embodiment of the present invention.

FIG. 4 is a sectional view showing another modified embodiment of the present invention.

FIG. 5 is a sectional view showing still another embodiment of the present invention.

FIG. 6 is a cross-sectional view for explaining a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Key top 2 Case of apparatus 4 Membrane sheet 5 Printed wiring board 6 Light source 7 Transparent film sheet 8 Light guide plate 9 Emboss sheet

Claims (3)

(57) [Scope of request for utility model registration] 1. A. First Embodiment B. a key top formed by a transparent flat plate; Characters and symbols indicating the function to be assigned to each key top are printed on the positions where the key tops are to be bonded, and a paint for enhancing the light guiding effect is applied on the back side, and each key top is formed by a transparent insulating film. B. a transparent film sheet having a projection formed of a resin material at a position on the back side opposite to the top; A transparent resin plate that is laminated and united on the lower surface of this transparent film sheet and has a hole having a shape larger than the planar shape of the key top at a position facing the key top .
And a light guide plate comprising: a key top support structure comprising: 2. The light guide plate according to claim 1 , wherein a hole formed in said light guide plate is formed on a lower surface of said light guide plate.
Laminated embossed sheet with dome-shaped body
Then, a membrane sheet is further laminated and united on the lower surface of the embossed sheet, a switch provided on the membrane sheet is opposed to a position of a hole formed in the light guide plate, and the dome-shaped body is formed by the key top through the hole.
It is pressed and deformed, and the above-mentioned
A key switch configured to turn on and off the switch of the blend sheet . 3. The key switch according to claim 2, wherein a printed board is laminated on the lower surface of the membrane sheet, a light source is mounted on the printed board, and the light source is passed through a hole formed in the membrane sheet. A key switch, wherein the key switch is configured to be inserted into a light source engaging portion formed on a plate and transmit light from the light source to the key top through the light guide plate and the transparent film sheet.