JP4941516B2 - Membrane keyboard - Google Patents

Description

  The present invention relates to a membrane keyboard used for a personal computer or the like.

  A conventional membrane keyboard has two membrane sheets on a reinforcing plate, the two membrane sheets are arranged to face each other via a spacer, and electrodes are printed on each membrane sheet. When the key top is pressed, the upper membrane sheet is pressed, the two electrodes come into contact with each other, and the key switch is turned on. A conventional membrane sheet is divided into an upper sheet 1 and a lower sheet 2 as shown in FIG. 2, and the printed patterns on the sheets 1 and 2 are connectors of a keyboard control circuit board (not shown) by lead lead portions 3 and 4, respectively. Connected to.

  However, if the upper sheet and the lower sheet have different structures, a lead lead-out portion is required for each, and two keyboard control board connectors are also required. For this reason, the manufacturing cost is increased, and recently, a single-sheet membrane sheet in which lead lead portions as shown in FIG. An example of a single sheet membrane sheet is disclosed in Patent Document 1 below.

  As shown in FIG. 3, when the membrane sheet 5 has a single structure, a connection portion 8 for connecting the upper and lower sheets 6 and 7 is required. When the lead lead portion 9 is provided in the lower sheet 7, a pattern for routing the pattern of the upper sheet 6 to the lower sheet 7 is arranged in the connecting portion 8. By using such a single sheet membrane sheet, The lead lead-out portion is reduced, and the manufacturing cost can be reduced.

Japanese Patent Laid-Open No. 9-245563

  However, in the conventional keyboard structure using the single membrane sheet, when assembling the keyboard, the single membrane sheet is pressed and fixed to the reinforcing plate 11 from above by the key switch holder 10 as shown in FIG. However, the vicinity of the connecting portion 8 of the membrane sheet 5 is bent and bent. As shown in FIG. 4, the bending in the connecting portion 8 is greatly curved and deformed on the upper side because the reinforcing plate 11 is on the lower side, and the curved top portion 8 a is positioned higher than the lower surface of the key switch holder 10. .

  Since the top portion 8a of the connection portion 8 is higher than the key switch holder 10, the upper sheet 6 tends to float upward due to the influence, and the portion of the electrode 12 provided near the connection portion 8 is Distorted. A post 14 is provided between the key switch holder 10 and the reinforcing plate 11, but the upper sheet 6 is movable in the horizontal direction because it is necessary to contact the electrodes 12 and 13 when the switch is pressed. 8 may cause the upper sheet 6 to be distorted.

  When the upper electrode 12 is distorted, the distance between the upper and lower electrodes 12 and 13 changes, and the pressing characteristics such as the stroke and pressing force when the key is pressed are changed. There was a problem that the switch would turn on even though it did not.

In order to solve the above-described problems, the present invention is configured to form upper and lower membrane sheets by bending a membrane sheet having a connection portion at the connection portion and facing each other through a spacer, and extending the lower membrane sheet to the connection portion. In the membrane keyboard, which is disposed on the existing reinforcing plate and disposed with the electrodes facing the upper and lower membrane sheets, the connecting portion is formed narrower than the upper membrane sheet and the lower membrane sheet. In the folded state, the upper membrane sheet and the lower membrane sheet are displaceable, and a clearance hole is provided at a position facing the connection portion of the reinforcing plate to release bending due to the bending of the connection portion. larger only partial flexures under side of the connecting portion by which enter only bending of the connecting portion to the relief bore Ku formed, characterized in that eliminating the distortion of the upper membrane sheet.

According to the present invention, since the connecting portion for connecting the upper membrane sheet and the lower membrane sheet deflection enters the escape hole is made larger on the lower side, bending of the connecting portion occurs distortion in the upper membrane sheet It wo n’t let you.

It is sectional drawing which shows the membrane keyboard of embodiment of this invention. It is a perspective view which shows the conventional membrane sheet. It is a perspective view which shows the conventional membrane sheet. It is a perspective view which shows the conventional problem. It is a perspective view which shows the membrane sheet of other embodiment. It is a perspective view which shows the membrane sheet of other embodiment. It is sectional drawing which shows the membrane sheet of other embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a membrane keyboard according to an embodiment of the present invention. In FIG. 1, the membrane keyboard 20 according to the embodiment includes a key top 21, a cup rubber 22, an actuator 23, a key switch holder 24, a membrane sheet 25, and a reinforcing plate 26. The membrane sheet 25 is configured by connecting an upper sheet 27 and a lower sheet 28 with a connection portion 29, and an electrode 30 is printed on the upper sheet 27 and an electrode 31 is printed on the lower sheet 28, respectively. A spacer 32 is disposed between the upper sheet 27 and the lower sheet 28 to maintain a predetermined interval.

  The structure of the membrane sheet 25 is the same as that shown in FIG. The membrane sheet 25 is disposed on the reinforcing plate 26, is held between the key switch holder 24, and is fixed in position by a columnar post 33 extending from the key switch holder 24. That is, the post 33 is formed integrally with the key switch holder 24, and protrudes to the lower side of the reinforcing plate 26 through the holes formed in the membrane sheet 25, the spacer 32 and the reinforcing plate 26, and the protruding lower end portion is formed. The membrane sheet 25 is fixed between the reinforcing plate 26 and the key switch holder 24 by connecting the key switch holder 24 and the reinforcing plate 26 with the post 33 in this way. The key switch holder 24 is provided for each key switch, and a plurality of posts 33 are provided for each key switch holder 24. The post 33 is firmly fixed by pressing the lower sheet 28 against the reinforcing plate 26. However, the upper sheet 27 is not fixed so as not to move completely because the upper sheet 27 is fixed at intervals. The key switch holder 24, the reinforcing plate 26 and the post 33 constitute a fixing means for the lower sheet 28.

  A relief hole 34 is formed at a position of the reinforcing plate 26 facing the connection portion 29 of the membrane sheet 25. By forming the escape hole 34, the bent portion of the connection portion 29 enters the escape hole 34, and the bent portion is formed on both the upper side and the lower side of the connection portion 29.

  By providing the escape hole 34, the influence of the bending of the connecting portion 29 on the upper sheet 27 is reduced while the influence of the bending of the upper sheet 27 has been reduced. The sheet 27 is not distorted. That is, the influence that the upper sheet 27 is distorted disappears.

  5 and 6 are perspective views showing a membrane sheet according to another embodiment. 6 shows a state in which the front and back sides are reversed with respect to FIG. In the membrane sheet shown in the embodiment shown in FIG. 1, the bending of the connection portion 29 is almost equal between the upper side and the lower side. However, in the membrane sheet 40 shown in FIGS. The portion 43 is largely bent toward the lower sheet 42 as a whole. 5 and 6, a cut portion 44 is formed in the lower sheet 42, and a connection portion 43 is formed between the cut portions 44. When the upper and lower sheets 41, 42 are opposed to each other by bending at the connecting portion 43, the upper sheet 41 side is bent as shown in FIG. 6 by bending at the boundary between the edge 45 of the upper sheet 41 and the connecting portion 43. It can be made to hardly occur. That is, the cut portion 44 constitutes a means for bending the lower sheet 42 more.

  FIG. 7 shows a membrane keyboard using the membrane sheet of another embodiment. In FIG. 7, a relief hole 34 is formed in the reinforcing plate 26 as in the above embodiment. The bending of the connecting portion 43 bent toward the lower sheet 42 enters the escape hole 34, and the influence of the bending hardly reaches the upper sheet 41. At this time, since the lower sheet 42 is fixed by being brought into close contact with the reinforcing plate 26 by the post 33, the lower sheet 42 is not distorted even under the influence of the bending of the connecting portion 43.

  In another embodiment, the notch 44 is formed in the lower sheet 42, but the edge positions of the upper sheet 41 and the lower sheet 42 are shifted so that the bending of the connecting portion 43 is entirely on the lower sheet 42 side. In this case, the cut portion is not necessarily required.

  In each of the above embodiments, the escape hole 34 is formed so as to penetrate the reinforcing plate 26 as a deflection escape portion of the connection portion 43, but the shape of the relief hole can escape as much as the deflection portion of the connection portion 29 is necessary. Any shape may be used, and the shape is not necessarily limited to the shape of the above embodiment. Furthermore, you may make it provide a notch in a reinforcement board as an escape part of bending.

  As described above in detail, according to the present invention, since the relief portion is formed at a position facing the connection portion of the membrane sheet, the upper sheet of the membrane sheet is not distorted, and the switch The pressing characteristic of the button does not change, and the malfunction of turning on when not pressed is also prevented.

20 Membrane keyboard 25, 40 Membrane sheet 26 Reinforcement plate 27, 41 Upper sheet 28, 42 Lower sheet 29, 43 Connection 34 Relief hole

Claims (2)

Folding the membrane sheet having the connection part at the connection part, constituting the upper and lower membrane sheets by facing each other through the spacer, and arranging the lower membrane sheet on the reinforcing plate extending to the connection part, In the membrane keyboard where the electrodes are arranged facing the upper and lower membrane sheets,
The connecting portion is formed narrower than the upper membrane sheet and the lower membrane sheet, and can be displaced with respect to the upper membrane sheet and the lower membrane sheet in a folded state,
At a position opposite to the connecting portion of the reinforcing plate, the provided escape hole for releasing the deflection due to bending of the connecting portion, wrinkles only bending of the connecting portion on the lower side of the connecting portion by which enter into the escape hole Membrane keyboard characterized by a larger ridge and no distortion of the upper membrane sheet. A cut portion is formed in the lower membrane sheet, and the connecting portion is formed between the cut portions,
The membrane keyboard according to claim 1, wherein the connecting portion is bent so that the upper membrane sheet and the lower membrane sheet are opposed to each other , and is bent at the boundary between the end portion of the upper membrane sheet and the connecting portion.

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