JP2001100889A - Keyboard - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a keyboard which has a waterproof function in a single body and moreover user a membrane switch which does not damage air vent function. SOLUTION: A membrane switch 20 is integrated, while interposing a spacer sheet 23 so as to form an electrode isolation space between a flexible upper electrode sheet 21 and a lower electrode sheet 22. On the upper surface of the upper electrode sheet, a soft hollow cushion part 13 is adhered and arranged tightly. On the upper electrode sheet 21, an air vent hole 21A is formed for communicating the electrode isolation space to the internal space of the cushion part. In addition, at the upper part of the cushion part 13, an air vent hole 13E is formed in the longitudinal direction for communicating the internal space to the outside.

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 FIG. 5 and 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. 5, a membrane switch 20 comprises a flexible upper electrode sheet 21 made of PET (polyethylene terephthalate), a lower electrode sheet 22 made of PET, and a PET electrode interposed therebetween. 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 are usually fixed (joined) by ultrasonic fusion. There are usually 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.

In recent notebook PCs, instead of the structure of FIG. 5, instead of 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. 8 is a longitudinal sectional view showing the conventional cushion portion 13 alone. This cushion portion 13 is hollow. The pedestal portion 13A of the cushion portion 13 is formed with a lateral air vent portion (air inlet / outlet) 13B. The air vent 13B is used for adjusting the air pressure in the internal space 13C. The lower end of the pedestal portion 13A is adhered to the membrane switch 20 with an adhesive 13D. Without the air vent 13B, the load when pushing the cushion 13 increases. Further, the pressure of the air confined in the internal space 13C surrounded by the cushion portion 13 and the membrane switch 20 fluctuates due to the fluctuation of the outside air, and the above-mentioned load changes (Boyle-Charles law).

FIG. 9 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 indispensable 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 even happens to stay on. Air passages 28 are formed between the upper sheet 21 and the spacer sheet 23 and between the lower sheet 22 and the spacer sheet 23 without having to create an air vent window in the spacer sheet 23.

[0010]

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.

An object of the present invention is to provide a keyboard having a membrane switch structure which has a high waterproof function and does not impair the air vent function.

[0012]

SUMMARY OF THE INVENTION A keyboard according to the present invention is configured such that an electrode isolation space is formed by a contact between a flexible upper electrode sheet and a lower electrode sheet each having a contact formed on a facing surface. A membrane switch integrated with a spacer sheet interposed therebetween; a flexible hollow cushion portion disposed in close contact with the upper surface of the contact portion of the upper electrode sheet; and a cushion portion disposed on the cushion portion A key operation section for pressing the upper electrode sheet toward the lower electrode sheet side via a first electrode sheet, and a first operation section for communicating the electrode isolation space with the internal space of the cushion section in the upper electrode sheet. Air vent hole is formed, and a second air vent hole is formed in the upper part of the cushion portion in a vertical direction for communicating the internal space with the outside. And wherein the door.

According to the present invention, the hollow cushion portion is disposed in close contact with the upper surface of the upper electrode sheet of the membrane switch, and the upper electrode sheet communicating with the internal space of the cushion portion and the internal space above the cushion portion. An air vent hole is formed in each of the communicating portions, and a portion exposed outside the air vent hole is arranged at an upper portion of the cushion portion, that is, the highest position, and the upper portion of the cushion portion is covered from above by the key operation portion. Even if you spill coffee or tea on the keyboard,
This does not enter the inside of the membrane switch through the air vent hole. For this reason, a high waterproof function can be realized, and the air vent function is not impaired at all.

In order to prevent the intrusion of liquid from the close contact portion between the upper electrode sheet and the cushion portion and to realize a higher waterproof function, the close contact portion of the cushion portion with the upper electrode sheet must have an electrode. It is desirable that the sheet is adhered to the sheet without any gap.

Further, in the present invention, a second air vent hole of the cushion portion is provided at a lower portion of the key operation portion so as to prevent an air vent hole at an upper end of the cushion portion from being closed by a lower end portion of the key operation portion. It is desirable that a communicating groove is formed.

In a preferred embodiment, the membrane switch has, for example, a plurality of contact portions, and the electrode isolation spaces of the plurality of contact portions are connected to each other. In this case, the first air vent hole of the upper electrode sheet is
What is necessary is just to form in only some contact parts among the said several contact parts.

[0017]

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 a contact portion of a keyboard using a cushion-portion-mounted membrane switch with an air vent according to an embodiment of the present invention. The basic configuration of this keyboard is the same as that of the related art, and a key operation section including a finger touch section 11 and a pantograph movable section 12, a key top section 11 including a cushion section (silicone rubber molded product) 13 with an air vent, and a membrane switch 20 and a metal support plate 30.

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 26 made of an acrylic material. On the opposing surfaces of the upper and lower electrode sheets 21 and 22, contact portions (Ag printed circuit) 24 are pattern-formed by screen printing or the like. The membrane switch 20 includes a metal support plate 30.
Supported by The movable part 1 of the key top part 10
The lower end of 2 is supported by a projection 31 standing upright from the support plate 31 and passing through the projection insertion hole 29 of the membrane switch 20.

The difference between the keyboard having the structure shown in FIG. 1 and the conventional structure is that the position of the air vent (27 in FIG. 9), which is conventionally located near the outer side of the membrane switch 20, is changed to the vicinity of the contact portion 24 of the membrane switch 20. Is that air vent holes 21A (first air vent holes) are provided in the upper electrode sheet 21 of FIG. Further, the cushion portion 13 has an air vent hole 13E formed in the upper wall, not in the pedestal portion, but in the vertical direction. Then, the cushion portion 13 is mounted on a position corresponding to the contact portion 24 of the upper electrode sheet 21 with an adhesive 13D having a good sealing property so as not to form a gap. With this structure, the air vent hole 21A of the membrane switch 20 is covered with the cushion portion 13.

Even if this structure is immersed in water (however, the air vent hole 13E of the cushion 13 must be exposed to the air), water does not enter the membrane switch 20.
Even if you spill coffee (at most 20-20
0 cc), and the function of the switch of the membrane 20 is not lost.

The size of a normal notebook PC (A4 type) keyboard is about 270 mm × 110 mm. The height h1 from the upper surface of the upper electrode sheet 21 of the membrane switch 20 to the upper portion of the cushion portion 13 with the air vent is:
As shown in FIG. 1, when the key top is not pressed, h1
= About 3 to 5 mm.

FIG. 2 shows the movable portion 1 which prevents the upper portion of the cushion portion 13 with air vent from contacting with the projection 12A of the movable portion 12 when the key top is pressed.
2 shows a groove 12B for an air inlet / outlet formed on a second protrusion 12A (a view from directly above). The groove 12B may be formed to cross in a cross shape as long as it communicates with the air vent hole 13E.

On the other hand, as shown in FIG. 3, the height h2 from the surface of the upper electrode sheet 21 to the upper end of the cushion portion 13 with the air vent when the key top is pressed.
Is about 2.5 to 4 mm. If the liquid is applied to the PC body with the keytop pressed, the height h2
Is considered to be a minimum of 2.5 mm, “2.5 mm × 270
Even if a liquid of up to 74.25 cc is applied, there is no problem in function. "

Furthermore, for a small PC such as an A5 size, the keyboard area is reduced, so that even when the same amount of liquid is spilled, the height of the accumulated liquid becomes high and the situation becomes severe. In order to make it possible to apply a large amount of liquid including such a case, the design of the height h2 shown in FIG. 3 is increased, that is, the height of the cylindrical portion 13F at the upper end of the cushion portion 13 is increased. Can be dealt with by designing high (this part can be freely changed in design).

In the state of being incorporated in the housing (the state of the finished product), as shown in FIG. 7, since the finger touching portion 11 acts just as an umbrella for the liquid L falling from above, the PC
It is only necessary to worry whether or not the liquid applied to the reservoir accumulates and exceeds h2.

The air vent hole 13E of the cushion portion 13 and the air vent hole 21A of the membrane do not need to be formed for all keys of the membrane switch 20, but it depends on the design of the air passage (28 in FIG. 9). About 1 to 3 places are sufficient.

The air vent hole 13E of the cushion portion with the air vent can be realized by forming a fine hole in the cushion portion 13 of the existing design with a laser or the like. In addition, the air vent hole 21A of the membrane may be formed by a metal mold when the outer shape of the upper electrode sheet 21 is processed.

FIG. 4 shows a different design example of the air vent near the upper sheet contact point (a view from directly above). In the figure, 21A indicates a mounting land (application pattern of the adhesive 13D) of the cushion portion 13 with an air vent, 24U indicates an Ag circuit pattern of the upper sheet 21, 24D indicates an Ag circuit pattern of the lower sheet 22, and 23A indicates a spacer hole. I have. A is an air vent according to design 1, B is an air vent according to design 2, and C is an air vent according to design 3. Alternatively, the air vent can be designed in the center.

In summary, according to the present invention, 1) an air vent hole 21A is provided in the contact portion of the upper electrode sheet 21 of the membrane switch 20 (inside to which the cushion portion 13 is bonded), and 2) (key load characteristics are created). ) Cushion part 1
3 also has an air vent hole 13E at the upper part (this air vent hole 13E is not only the click characteristic of the cushion portion 13 itself, but also the air vent hole 21E of the membrane switch 20).
A is also for maintaining the characteristics of the contact switch portion of the membrane switch 20 by connecting to the A). 3) The air vent hole 13E of the cushion portion 13 hits the movable portion 12 of the key top (the portion pressing the upper end portion of the cushion portion). 4) If necessary, when the cushion portion 13 is crushed by the movable portion 12, the air vent 13 of the cushion portion 13 is designed.
5) A cushion 13 is mounted on the upper electrode sheet 21 (at this time, a pedestal portion 13A of the cushion is completely covered with an adhesive 13D, and a groove 12B is formed on the upper electrode sheet 21). The air inlet / outlet in the space 13C surrounded by the cushion portion 13 is only the air vent hole 13E.) 6) The membrane body 20 uses the upper sheet, the spacer, and the lower sheets 21, 22, 23 as an adhesive (adhesive).
26, be sure to completely close the assembling hole and the vicinity of the outer shape with each sheet and adhesive.
The air inlet / outlet of 0 is only the air vent hole 21A.

[0030]

According to the present invention, it is possible to realize a membrane switch which has a waterproof function by itself and does not impair the air vent function, and the following effects can be expected. 1) The positions of the cushion portion with the air vent and the contact portion with the air vent can be freely arranged (provided that there is a contact point and the cushion portion is mounted). 2) The air vent design position in the above 1) can be performed by providing a dummy mounting portion (for example, beside a space key). With such a design, the design of the air vent of the membrane can be designed without considering the change in the load characteristics of the key. 3) As the manufacturing process, only the conventional cushion part mounting is performed, so that a porous film of tetrafluoroethylene resin (which does not allow water droplets but allows air and water vapor to pass) is useful for realizing a waterproof structure. For a membrane with no space, a low-cost and highly reliable dustproof and drip-proof (waterproof) structure can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a keyboard according to an embodiment of the present invention.

FIG. 2 is a top view of the cushion unit alone shown in FIG. 1;

FIG. 3 is a cross-sectional view illustrating a pressed state of FIG. 1;

FIG. 4 is a top view showing a modification of the air vent of the upper sheet.

FIG. 5 is a sectional view of a main part of a conventional keyboard.

6 is an external view of FIG.

FIG. 7 is a side view showing a conventional cushion unit alone.

FIG. 8 is a sectional view of a main part showing another example of a conventional keyboard.

FIG. 9 is an enlarged plan view showing a conventional membrane switch alone.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Key top part, 11 ... Finger touch part, 12 ... Movable part, 12B ... Groove, 13 ... Cushion part, 13C ... Internal space, 13D ... Adhesive, 13E: air vent of cushion part, 20: membrane switch, 21: upper electrode sheet, 22: lower electrode sheet, 23: spacer sheet, 24: electrode, 26: adhesion 29, air vent of membrane, 30 ... support plate.

Claims (5)

[Claims] 1. A membrane integrated with a spacer sheet interposed between a flexible upper electrode sheet and a lower electrode sheet each having a contact portion formed on an opposing surface so as to form an electrode isolation space at the contact portion. A switch; a flexible hollow cushion portion disposed in close contact with the upper surface of the contact portion of the upper electrode sheet; and a lower electrode which is disposed on the cushion portion and passes the upper electrode sheet through the cushion portion to the lower electrode. A key operation section for pressing the seat side; a first air vent hole is formed in the upper electrode sheet for communicating the electrode isolation space with the internal space of the cushion section; A keyboard, wherein a second air vent hole is formed in an upper portion in a vertical direction for communicating an internal space thereof to the outside. 2. The keyboard according to claim 1, wherein the cushion portion has a close contact portion with the upper electrode sheet bonded without a gap. 3. The keyboard according to claim 1, wherein a groove communicating with a second air vent hole of said cushion portion is formed in a lower portion of said key operation portion. 4. The keyboard according to claim 1, wherein the membrane switch has a plurality of contact portions, and the electrode isolation spaces of the plurality of contact portions are connected to each other. 5. The keyboard according to claim 4, wherein the first air vent hole of the upper electrode sheet is formed only in a part of the plurality of contact portions.