JP2001101950A - Keyboard - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waterproof keyboard as a single piece and with membrane switch that does not damage the air venting function. SOLUTION: A waterproof type of keyboard comprises a membrane switch (20) combined with a spacer sheet interposed between upper and lower flexible electrode sheets to form an electrode isolating space between the electrode sheets, a supporting plate for supporting the membrane switch (20) at an upper surface thereof and forming a space for waterproof at the lower surface thereof. At the lower electrode (22) of the membrane switch (20), a first air-ventilating hole 51 is formed for communicating the electrode isolating space with outer space. At the supporting plate (30), a second air-ventilating hole (52) is formed in the position corresponding to the first air-ventilating hole (51). These air- ventilating holes (51) and (52) are water tightly connected by an adhesive (70).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a keyboard having a membrane switch used for a personal computer (PC) and the like, and more particularly to a keyboard having improved resistance to coffee spilling and waterproofness by using a membrane switch alone.

[0002]

2. Description of the Related Art Conventionally, a keyboard using a membrane switch of this type has a key top 10 which is actually touched by a finger as shown in a schematic cross section of FIG. 4 and an exploded perspective view of FIG. A membrane switch 20 that is turned on and off by being operated by the key top 10;
A support plate 30 made of a metal such as Fe or Al for supporting these components is provided.

The key top portion 10 includes a finger touch portion (key) 11 of a plastic molded product, a movable portion 12 that can be extended and contracted in a pantograph type in the vertical direction, and a rubber cushion portion 13.
And a plastic base portion 14 used for positioning the cushion portion 13 and attaching the movable portion 12.

As shown in FIG. 4, a membrane switch 20 includes a flexible upper electrode sheet 21 made of PET (polyethylene terephthalate), a lower electrode sheet 22 also made of PET, and a PET It has a three-layer structure including the spacer sheet 23. Contact portions (A) are provided at opposed positions inside the upper and lower electrode sheets 21 and 22.
g printed circuit) 24 are formed by printing. These sheets 21, 22, and 23 are positioned by a jig or the like (three sheets are accurately overlapped) and fixed (joined) by a method such as ultrasonic fusion. There are two places where ultrasonic welding is performed.
The size of the fused portion 25 is a circular shape of about φ2.0 to φ3.5 mm. The membrane switch 20 is provided with a contact 2
4 is formed of a membrane switch body 46 and a connector tail portion 40 extending from the membrane switch body 46 and electrically connecting the membrane switch 20 to a motherboard of the PC body.

In recent notebook PCs, rather than the structure of FIG. 4, the structure of FIG.
A projection insertion hole 29 is formed in the membrane switch 20, and a projection 31 erected from the support plate 30 penetrates the projection insertion hole 29, and the movable part 12 (pantograph) of the keytop 10 is directly connected to the metal through the projection 31. The structure which fits in the support plate 30 made of a product is the mainstream. The projection 31 for fitting the pantograph is formed by pressing, deforming, and molding the support plate 30 in advance using a mold.

With such a structure, the membrane switch 20 is equivalent to being exposed. The coffee spilling resistance (or waterproofness) is originally a note P
C is required for a finished product, but recently, since the membrane switch 20 is almost exposed, it is also required for a membrane switch as a component alone.

FIG. 7 is a plan view showing an example of a conventional membrane switch 20 having a dust-proof and drip-proof structure used for a keyboard of the type shown in FIG. This membrane switch has a structure in which an adhesive (adhesive) 26 for dustproof and drip-proof is applied so as to surround the projection insertion hole 29 into which the projection 31 of the support plate 30 is inserted. The pressure-sensitive adhesive 26 also serves to bond three sheets 21 to 23 together. Also, in this membrane switch 20,
The electrode isolation space including the contact portion 24 is completely sealed and the contact portion 2
In order to prevent the on / off operation of 4 from being disturbed,
An air vent 27 is formed on the outer part.

The air vent 27 is an essential structure for the membrane switch 20. If the air vent 27 is closed for some reason, the load characteristics as a switch will change due to changes in the outside air temperature and pressure. In the worst case, it does not turn on at all or even keeps on. Upper sheet 21 and spacer sheet 23
And between the lower sheet 22 and the spacer sheet 23 are air passages 28 without the need to create an air vent window in the spacer sheet 23.

[0009]

In the above structure, when a liquid (coffee, juice, water, etc.) is spilled on the keyboard, the liquid enters the membrane contact portion from the air vent portion 27 of the membrane, and the circuit 24 is turned off. Short-circuits and stops functioning as a switch. For example, note P
If coffee is spilled to the keyboard during work at C, file operation (key input) becomes impossible, and data during work is lost.

The present invention has been made in view of the above points, and has as its object to provide a keyboard having a membrane switch structure that has a high waterproof function and does not impair the air vent function.

[0011]

According to the keyboard of the present invention, the contact portion forms an electrode isolation space between the flexible upper electrode sheet and the lower electrode sheet each having a contact portion formed on the opposing surface. A membrane switch integrated with a spacer sheet interposed therebetween, and a support plate that supports the membrane switch on the upper surface and forms a waterproof space on the lower surface. A first air vent for communicating with a space is formed, a second air vent is formed on the support plate at a position corresponding to the first air vent, and the first air vent and the first air vent are formed on the support plate. The air vent portion 2 is characterized in that at least its peripheral portion is connected in a watertight manner.

According to the present invention, the air vent portion (first air vent portion) of the membrane switch is bonded to the air vent portion (second air vent portion) of the support plate by, for example, an adhesive or the like, thereby making the membrane switch watertight. The liquid can be prevented from entering the electrode isolation space of the membrane switch from the space between the membrane switch and the support plate. Further, since the electrode isolation space of the membrane switch communicates with the waterproof space below the support plate via the first and second air vents, the air vent function is not impaired.

If the first and second air vents are formed, for example, in the vicinity of an enter key or a space key, the design is easy, but a connection without gaps between the first and second air vents can be realized. If so, it may be provided at any position of the membrane switch and the support plate.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments shown in the drawings. FIG. 1 is a cross-sectional view of the vicinity of an air vent section showing one embodiment of the present invention. FIG. 2 is an expanded plan view showing a membrane switch and a support plate according to an embodiment of the present invention.

The membrane switch 20 includes an upper electrode sheet (PET film) 21, a spacer sheet (PET film) 23, and a lower electrode sheet (PET film) 22
Are bonded together with a material having excellent sealing properties, for example, an adhesive of acrylic material (corresponding to 26 in FIG. 4). On the opposing surfaces of the upper and lower electrode sheets 21 and 22, a contact portion (Ag printed circuit), not shown, is patterned by screen printing or the like. Spacer sheet 2
3 forms an electrode isolation space at this contact portion. Sheet 2
Between 1, 2, 23, there is an air passage (corresponding to 28 in FIG. 7) indicated by an arrow in the figure communicating with the electrode isolation space. The membrane switch 20 is supported by a support plate 30 made of a metal plate.

In the structure shown in FIG. 1, the position of the conventional air vent (27 in FIG. 7) at the outer edge of the membrane switch main body 46 is changed in design, and the air vent is provided on the back surface (the surface in contact with the support plate 30) of the membrane switch main body 46. A hole (first air vent) 51 is provided. An air vent hole (second air vent portion) is also provided on the support plate 30 side at a position corresponding to this.
52 are provided. The lower electrode sheet 22 of the membrane switch 20 and the support plate 30 are joined to each other around the air vent holes 51 and 52 by an adhesive 70 without any gap. Therefore, the air vent hole 51 of the membrane switch 20 and the air vent hole 52 of the support plate 30 are connected in a watertight manner.

Instead of the adhesive 70, a double-sided adhesive sheet such as a double-sided tape can be used. However, in order that the air vent hole 51 of the membrane switch 20 and the air vent hole 52 of the support plate 30 can be connected without a gap, as shown in FIG. Make it as large as possible so that it is 2.5 mm or more.

Although not shown in the drawing, the membrane between the upper electrode sheet 21 and the spacer sheet 23 and between the spacer sheet 23 and the lower electrode sheet 22 in the vicinity of the air vent portion, as shown in FIG. As in the case of the connection in the main body, they are bonded with a dustproof and waterproof adhesive. With such a structure, even if coffee or juice is spilled on the keyboard of the notebook PC, they are prevented from entering the inside of the membrane switch 20.

Air vent hole 5 of membrane switch 20
If 1 is arranged in the vicinity of a space key or a return key (enter key) which can take a relatively effective space in the keyboard, the design becomes easy. However, the air vent hole 51 of the membrane switch 20 may be provided at an arbitrary position inside the membrane main body as long as a connection without a gap can be realized with the air vent hole 52 of the support plate 30.

In short, according to the present invention, 1) an air vent hole is provided in the lower electrode sheet (surface to be attached to the support plate) of the membrane switch; and 2) an air vent of the support plate is overlapped with the air vent hole of 1). A hole is provided. 3) The membrane switch body (especially in the vicinity of the air vent hole) and the support plate are adhered to each other with an adhesive (or an adhesive) having good adhesion. 4) The adhesive (or an adhesive) is used for the above 1). And 2) bonding around the air vent hole without gaps. 5) Membrane switches (upper electrode sheet, spacer sheet, lower electrode sheet) are stuck together with adhesive (or adhesive) with good adhesion. The vicinity was completely closed with the above-mentioned respective sheets and the adhesive, and the air inlet / outlet (air vent) of the membrane switch was only the above 1).

[0021]

As described above, according to the present invention, it is possible to realize a membrane switch which has a waterproof function in itself and does not impair the air vent function. In addition, since it is not necessary to attach an expensive waterproof film (for example, a porous film of tetrafluoroethylene resin) to the main body of the membrane (near the key array portion), the size of the membrane switch can be reduced. As a result, the overall size can be reduced and the cost of the product can be reduced. As described above, according to the present invention, an inexpensive and highly reliable dustproof and drip-proof (waterproof) structure can be realized for a small-sized membrane. Therefore, the present invention is effective in most membranes that require dustproof, dripproof and waterproof functions when there is no space for attaching the waterproof film as described above.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing an embodiment of the present invention.

FIG. 2 is an exploded plan view showing a membrane switch and a support plate according to an embodiment of the present invention.

FIG. 3 is a plan view of the vicinity of an air vent according to the present invention.

FIG. 4 is a sectional view of a main part of a conventional keyboard.

5 is an exploded perspective view of the keyboard shown in FIG.

FIG. 6 is a sectional view of a main part showing another example of a conventional keyboard.

FIG. 7 is an enlarged plan view showing a conventional membrane switch alone.

[Explanation of symbols]

10 ... key top, 20 ... membrane switch, 21 ...
Upper electrode sheet, 22 lower electrode sheet, 23 spacer sheet, 30 support plate, 51, 52 air vent holes,
70 ... adhesive.

Claims (3)

[Claims] 1. A spacer sheet is interposed between a flexible upper electrode sheet and a lower electrode sheet each having a contact portion formed on a facing surface so as to form an electrode isolation space at the contact portion. A membrane switch; and a support plate that supports the membrane switch on an upper surface and forms a waterproof space on a lower surface. The lower electrode sheet has a first air vent for communicating the electrode isolation space with an external space. A second air vent is formed on the support plate at a position corresponding to the first air vent, and at least a peripheral portion of the first air vent and the second air vent is watertight. A keyboard connected to the keyboard. 2. The peripheral part of the first air vent of the lower electrode sheet is adhered to the peripheral part of the second air vent of the support plate by an adhesive. The keyboard according to 1. 3. The keyboard according to claim 1, wherein the first and second air vents are formed near an enter key or a space key.