JPH0139370Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a transparent keyboard switch with uniform light transmittance on the touch surface and excellent transparency.

1A to 1J are exploded views showing the structure of a conventional transparent keyboard switch, and FIG. 2 is a side view showing its assembled state.

In FIGS. 1a and 1b, 1 is a transparent insulating sheet that is easily displaced by stress. In c and d, 2 is a transparent insulating sheet in contact with the insulating sheet 1, and 3 is a movable electrode group consisting of a very thin transparent conductive film of metal oxide or metal provided on the insulating sheet 2. It is. 4 more
is a movable contact, which is a part of the movable electrode group 3;
is a pattern showing a portion other than the movable contact 4 on the movable electrode group 3. In e and f, 6 is a spacer made of an insulating sheet that is in contact with the surface of the insulating sheet 2 on which the movable electrode group 3 is provided and has a hole penetrated in a portion corresponding to the movable contact 4, and 7 is a spacer. 6 is the part of the hole provided, and 8 is the part of the frame other than the hole on the spacer 6. In g and h, 9 is an insulating sheet in contact with the other surface of the spacer 6, 10 is provided on the insulating sheet 9, and is provided in contact with the movable electrode group 3 through the hole portion 7 of the spacer 6. A fixed electrode group consisting of a very thin transparent conductive film made of metal oxide, metal, etc. Also 11
1 is a pattern in which a fixed contact is a portion on the fixed electrode group 10 corresponding to the movable contact 4, and 12 is a portion other than the fixed contact 11. In i and j, 1
Reference numeral 3 denotes a reinforcing insulating sheet made of a transparent rigid body that is laminated and closely adhered to the other side of the insulating sheet 9 for the purpose of reinforcing the various sheets mentioned above.

The action is shown below based on FIG. When the insulating sheet 1 is pushed downward by external stress, the insulating sheet 2 is also displaced. Therefore, the movable contact 4 fixed to the insulating sheet 2 also moves downward. Therefore, the distance between the movable contact 4 and the fixed contact 11, which were located at a distance equal to the thickness of the spacer 6 when there was no pressure, is reduced.
The movable contact 4 and the fixed contact 11 come into contact and the circuit is closed. Even if the stress applied to the insulating sheet 1 increases, the insulating sheet 9 will not be displaced downward because it is reinforced with a reinforcing insulating sheet made of a transparent rigid body. Further, when the external stress applied to the insulating sheet 1 decreases, the displacement of the insulating sheet 1 returns to its original state, and the circuit is opened.

The insulating sheet of such a transparent keyboard switch and the reinforcing insulating sheet made of a transparent rigid body use polyester film, acrylic, glass, or the like with high light transmittance as the base material. Further, the above-mentioned parts are laminated in close contact for the purpose of equalizing the stroke and operating force, and for design reasons. However, in reality, the insulating sheet 1
It is difficult to completely bring the insulating sheet 2 and the insulating sheet 9 into close contact with the reinforcing insulating sheet 13, resulting in a contact area (in close contact) and a non-contact area (in a non-contact state). If the entire surface is fixed with adhesive, it is possible to make the whole sheet stick together, but using adhesive increases the cost and also causes new problems due to discoloration of the adhesive, so usually, each sheet is simply laminated. It's getting old. Therefore, depending on work conditions and environmental conditions (each sheet expands and contracts), contact areas and non-adhesion areas occur at random positions.

Here, the light transmittance of the close contact portion and the non-close contact portion will be explained. The intensity of the incident light is I ₀ , the intensity of the light transmitted through sheet 1 is I ₁ , the intensity of the light transmitted through sheet 2 is I ₂ , the reflectance of the surface of sheet 1 is R ₁ , sheet 1
Let R ₁ ' be the reflectance of the back surface (boundary surface with the air layer), R ₂ be the reflectance of the front surface of the sheet 2, and R ₂ ' be the reflectance of the back surface of the sheet 2.

First, when sheets 1 and 2 are in non-contact areas, there is an air layer between sheets 1 and 2, so I ₁ = I ₀ × (1 - R ₁ - R ₁ ') I ₂ = I ₀ × (1 −R ₁ −R ₁ ′) ×(1−R ₂ −R ₂ ′).

On the other hand, when sheets 1 and 2 are in close contact, there is no air layer between the two sheets, and the reflectance in this area changes (in the non-adherent state, the interface between sheet 1 and the air layer and The light is reflected at the interface between the air layer and the sheet 2, whereas in the close contact state, it is reflected at the interface between the sheets 1 and 2), and the overall transmittance changes.
In other words, the transmittance is higher in the close contact area than in the non-close contact area. For this reason, the transmittance of the touch surface a on the insulating sheet 1 corresponding to the movable contact and the fixed contact varies greatly depending on the location. This is not desirable for a transparent keyboard switch that allows for downward viewing. In such a case, if the insulating sheet 1 with a somewhat rough surface and the insulating sheet 13 made of a transparent rigid body are directly laminated, the touch surface a
The above transmittance non-uniformity is improved. However, in this case, the diffused reflection became significant and the light transmittance decreased, so that it could not be said to be sufficient as a transparent keyboard switch whose first priority is transparency on the touch surface a.

The present invention was developed to solve the above-mentioned problems, and aims to provide a transparent keyboard switch with uniform light transmittance on the touch surface and excellent transparency.

The transparent keyboard switch of the present invention includes a group of movable electrodes made of a transparent conductive material provided in a band shape on a first transparent insulating sheet that is displaced in response to external stress, and a group of movable electrodes made of a transparent conductive material provided in a band shape on a first transparent insulating sheet that is displaced in response to external stress, and a fixed electrode group provided in a strip shape in a direction perpendicular to the movable electrode group and arranged to face the movable electrode group; and a fixed electrode group interposed between the first and second insulating sheets, the movable electrode group and the fixed electrode group being interposed between the first and second insulating sheets. a spacer for holding the fixed electrode group at a predetermined interval; a transparent third insulating sheet laminated on the outside of the first insulating sheet; and the second insulating sheet.
A transparent keyboard switch having a fourth insulating sheet made of a transparent rigid body laminated on the outside of the insulating sheet, and in order to achieve the above object, the third insulating sheet and the first insulating sheet The transparent keyboard switch is characterized in that a large number of protrusions made of transparent resin are formed on the facing surface and the surface of the fourth insulating sheet facing the second insulating sheet. The present invention will be explained below using the drawings.

Note that parts having the same functions as those in FIG. 1 or FIG. 2 are given the same reference numerals, and explanations thereof will be omitted.

Fig. 3 is a side view of the embodiment of the present invention, Fig. 4 a to j
3 are an exploded plan view and an exploded side view of the parts that constitute FIG. 3. FIG. In the figure, reference numeral 14 denotes a large number of protrusions provided on the surface of the insulating sheet (third insulating sheet) 1 facing the insulating sheet (first insulating sheet) 2. Reference numeral 15 denotes a large number of protrusions provided on the surface of the reinforcing insulating sheet (fourth insulating sheet) 13 made of a transparent rigid body and facing the insulating sheet (second insulating sheet) 9. These protrusions 14, 15
Insulating sheets 1 and 2 and insulating sheet 9
and 13 are stacked with a predetermined interval (height of the protrusions). In the transparent keyboard switch constructed in this way, as in the conventional transparent keyboard switch, the insulating sheet 1 is displaced downward via the spacer 14 due to external stress, and the pressure is transmitted to the insulating sheet 2. Therefore, the movable contact 4 fixed to the insulating sheet 2 is also displaced via the spacer 6, the gap between it and the fixed contact 11 is reduced, and the movable contact 4 and the fixed contact 11 come into contact and the circuit is closed. to be accomplished. At this time as well, insulating sheets 9 and 1
3 is maintained at a predetermined distance by a protrusion 15.

Further, when the external stress applied to the insulating sheet 1 decreases, the displacement of the insulating sheet 1 returns to its original state, so that the movable contact 4 and the fixed contact 11 are separated and a circuit is opened. Therefore, even when the stress applied to the insulating sheet 1 is zero (steady state), there is no contact between the insulating sheet 1 and the insulating sheet 2, and the insulating sheet 9 and the insulating sheet 13 made of a rigid body. does not occur. Therefore, the conventional disadvantages regarding the transparency on the touch surface of the transparent keyboard switch are eliminated.

As is clear from the above description, according to the present invention, each insulating sheet is separated by a space created by a projection made of transparent resin. The contact points of each sheet are only at the portions provided with minute protrusions (for example, 100 to 1000 μm in diameter), and unlike conventional sheets, the sheets do not come into close contact with each other partially. That is, it is possible to obtain a transparent keyboard switch which has an excellent appearance and has a uniform light transmittance over the entire touch surface without the transmittance becoming high in some parts, and the effect of implementation is great.

[Brief explanation of the drawing]

Figures 1 a to j are an exploded plan view and an exploded side view showing an example of a conventional transparent keyboard switch, Figure 2 is a side view showing the assembled state of Figure 1, and Figure 3 is a side view of an embodiment of the present invention. , FIGS. 4a to 4j are an exploded plan view and an exploded side view of FIG. 3. 1... Insulating sheet (third insulating sheet), 2
...Insulating sheet (first insulating sheet), 9...
Insulating sheet (second insulating sheet), 13... insulating sheet made of a rigid body (fourth insulating sheet),
3...Movable electrode group, 6...Spacer, 10...Fixed electrode group, 14, 15...Protrusion.

Claims (1)

[Claims for Utility Model Registration] A movable electrode group made of a transparent conductive material provided in a band shape on a transparent first insulating sheet that is displaced in response to external stress, and a group of movable electrodes made of a transparent conductive material provided on a transparent second insulating sheet, a fixed electrode group provided in a strip shape in a direction perpendicular to the movable electrode group and arranged to face the movable electrode group; and a fixed electrode group interposed between the first and second insulating sheets, the movable electrode group and the fixed electrode group being interposed between the first and second insulating sheets. A spacer that holds the fixed electrode group at a predetermined interval, a transparent third insulating sheet laminated on the outside of the first insulating sheet, and a transparent rigid body laminated on the outside of the second insulating sheet. In a transparent keyboard switch having a fourth insulating sheet, a surface of the third insulating sheet facing the first insulating sheet and a surface of the fourth insulating sheet facing the second insulating sheet, A transparent keyboard switch characterized by having a large number of protrusions made of transparent resin.