JPH08204346A - Input-output device and preparation of membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent electrostatic discharge or contamination from entering a device from switch or lamp part. SOLUTION: A continuous membrane 13 is an insulating elastomer having a conductive part 43 and a light transmitting part 35 transmits the light from a light source 25. When an operating part 33 of a switch 3 is depressed, the pattern part 23 of the switch and the conductive part 43 are short-circuited.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to the field of electronic circuits. More specifically, the present invention relates to an input / output device with a lamp and a switch having a protection function against electrostatic discharge and dirt.

[0002]

BACKGROUND OF THE INVENTION Today's electrical equipment typically includes a keyboard, display, mouse, panel, and one or more other input / output devices for communicating information with a user. Such input / output devices often have light emitting diodes that indicate that a particular function is active or available. The top surface of the I / O device is usually provided with a hole through which such a light emitting diode projects from or is flush with the top surface of the I / O device to allow the user to see it. Also, the input / output device is provided with a hole through which the switch protrudes from or is flush with the top surface of the input / output device to allow the user to operate it.

[0003]

In many applications, it is true that providing input / output devices with light emitting diodes or switches that can be viewed and operated by the user is advantageous, but not problematic. Do not mean. For example, when a user rubs a rug with his foot to generate static electricity and then touches the light emitting diode, a high-voltage electrostatic discharge path may be formed from the user to the electric device through the light emitting diode. This high-voltage electrostatic discharge path causes serious damage to electrical equipment,
It may even be completely inoperable. The holes on the top of the I / O devices can form another high-voltage electrostatic discharge path, and liquids, dust, insects, or other foreign objects can enter these holes to contaminate electrical equipment or its operation. May be adversely affected.

French patent 2,517, published June 10, 1983,
No. 646 discloses an assembly in which LEDs are exposed on the surface of an input / output device. As described above, in such a design, an electrostatic discharge path is generated from the surface of the input / output device to the circuit board below the input / output device, and the electric device is easily damaged by the electrostatic discharge.

US Pat. No. 5,149,923 issued Sep. 22, 1992 discloses a backlight keypad for use in a small mobile phone system. A partially translucent overlay made of a flexible material is provided with raised keys backlit by a light source located on a substrate to which the keypad is attached. A conductive intermediate layer is compressed by manipulating this overlay. According to this design
Although the light source is insulated from electrostatic discharge, the light source is too far from the top surface of the keypad to attenuate the light from the light source and prevent the information in the panel from being sufficiently transmitted. Further, this keypad has a problem of high manufacturing cost.

US Pat. No. 4,458,123 of July 3, 1984 discloses an attachment for incorporating a discrete electric component such as an LED in a switch panel. A pair of holes are provided in the switch panel through which leads from the LEDs make contact with the electrical circuitry on the switch panel substrate. If the LEDs are close to or exposed on the surface of the panel, the panel is susceptible to damage from electrostatic discharge, as mentioned above.

German patent DE 35 41 776 of 27 May 1987
A1 discloses a switch panel in which a cover is provided on a circuit board thereunder. This cover does not completely cover the LED near the surface of the panel, therefore the LED and circuit board are susceptible to damage from electrostatic discharge.

European Patent 0 358 88 of March 21, 1990
5 A1 discloses a cover mat for a printed circuit board having protruding parts such as LEDs. This cover mat is made of insulating plastic. An embossing is formed in the area of the display element or LED of the cover mat, which acts as a mounting dome that can be inserted into the passage or opening corresponding to the LED of the control panel. The mounting dome covers the LED and acts to insulate the LED and the circuit board on which it is mounted from electrostatic discharge. Further, a button dome is formed on the cover mat to provide a switch for the control panel. Another operating element or button is provided which extends through an opening in the control panel corresponding to the button dome. Although this patent addresses the need to insulate the LEDs from electrostatic discharge, the manufacture of cover mats and control panel assemblies is not straightforward. This is because there is provided another mechanical component in the form of another button or operating element associated with the control panel and button dome or switch member to provide a switch that can be depressed by the operator. This requires the fabrication of components that are completely separate from the control panel, circuit board, cover mat and switch members formed therein.

[0009]

The input / output device for electric equipment of the present invention has a lamp and a switch. A circuit board is provided that includes the light emitting portion of the lamp and the first and second patterned portions of the switch. The light emitting portion of the lamp and the first and second pattern portions of the switch are covered with a continuous membrane of elastic material. An optical transmission section is formed in this membrane that allows the light from the light emitting portion of the lamp to pass through. The operating part of the switch is also formed on this membrane. The membrane also contains the conductive portion of the switch. When the operating portion of the switch is flexed by the user's finger or other force, the conductive portion of the switch connects the first pattern and the second pattern. This continuous membrane protects electrical equipment from electrostatic discharge and dirt through the input / output devices.

[0010]

1 shows an input / output device according to an embodiment of the present invention.
As used herein, "input / output device" means a keyboard, keypad, display device, panel, mouse, or any other device capable of exchanging information with a user. In this embodiment, the input / output device is shown as the panel 1. Although the panel 1 preferably forms part of the electrocardiographic electronic heartbeat recorder 100, in the present invention the panel 1 forms part of other types of electrical equipment such as computers, audio equipment, video equipment, measuring instruments and the like. It may be an eggplant. Panel 1
Has at least one switch 3 and one lamp 5.

FIG. 2 is a rotational exploded view of the input / output device of the embodiment of the present invention. The panel 1 has an overlay 29, a frame 27, a membrane 13, and a circuit board 7. The circuit board 7 includes the light emitting portion 25 of the lamp 5. In the present embodiment, the light emitting section 25 is a light emitting diode, but other light emitting elements such as a fluorescent element and an electroluminescent element can be used in the present invention.
In addition, the circuit board 7 includes the tab 15 and the pattern portion 23 of the switch 3.
Have. It may also have other components such as connectors, wires, patterns, etc.

A membrane 13 is formed to cover the upper surface of the circuit board 7 and extends at least on the light emitting portion 25 and the pattern portion 23. Membrane 13 is preferably formed of an electrically insulative, elastic, flexible, at least partially translucent material such as silicone rubber. The membrane 13 is an optical transmission part 35 of the lamp 5 and an operation part 33 of the switch 3.
Have. Further, the membrane 13 has a conductive portion 43 of the switch 3, but this portion is hidden by the operating portion 33 in FIG. Those skilled in the art will appreciate that the conductive portion 43 is not made of the same material as the rest of the membrane 13, but is made of a conductive elastomer or other conductive material. In the present embodiment, the other parts of the membrane 13 are translucent or transparent, but those skilled in the art will understand that only the light transmission part 35 is translucent or transparent so that light can pass from the light emitting part 25 to the surface of the panel 1. It will be appreciated that there is.

The membrane 13 is engaged and fixed to the circuit board 7 by interference-fitting a plurality of posts 17 formed integrally with the membrane 13 and extending downward therefrom into corresponding openings of the circuit board 7.

The membrane 13 hermetically seals the circuit board 7 and the components mounted on the circuit board 7 to prevent them from becoming dirty.
It has a function of insulating from electrostatic discharge caused by an operator's finger or other object that comes into contact with the switch 3 or the lamp 5.

The circuit board 7 and the membrane 13 are fixed to the frame 27 by the tabs 15 of the circuit board 7 and the holding snaps 58 of the frame 27 engaging and holding the membrane 13 therebetween.
The optical transmission unit 35 and the operation unit 33 of the membrane 13 penetrate through the openings 55 and 53 of the frame 27, respectively. The overlay 29 is fixed to the frame 27 by engaging the tabs 66 of the overlay 29 and the slots 56 of the frame 27. The light transmission section 35 and the operation section 33 of the membrane 13 penetrate through the openings 65 and 63 of the overlay 29, respectively. In this embodiment, the overlay 29 is character information that describes the functions of various switches and / or lights on the panel 1.
Having 69. Overlay 29 is preferably tailored to a particular country or language so that it can be easily attached to frame 27. This allows the overlay 29 with the textual information 69 written in a particular language to be added to other parts of the panel 1 near the end of the manufacturing process, or even at the time of use. As a first alternative embodiment, no character information is required, or the character information is transmitted to the optical transmission part of the frame 27 or the membrane 13.
It is conceivable to write directly on the operation unit 35 or the operation unit 33. In such an embodiment, panel 1 would not include overlay 29. As a second alternative embodiment, it is conceivable that no character information is needed or that the character information is written directly on the membrane 13. In such an embodiment, panel 1 does not have overlay 29 or frame 27. Also, the overlay 29 can be easily removed by the user and washed with normal detergent or water.

FIG. 3 is a partial sectional view of the lamp and switch of the input / output device of this embodiment, taken along the line AA in FIG.
FIG. 4 is an enlarged view taken along the line BB in FIG. The operation of the lamp 5 and the switch 3 will be described with reference to FIG. When a sufficient current is applied to the light emitting portion 25 of the lamp 5, the light emitting portion 25 emits light (preferably visible light, but may be infrared light or other invisible light). This light passes through the optical transmission unit 35 and gives information to the user visually or through detection by an infrared receiver.

In FIG. 4, switch 3 is in the open position. This is because the conductive portion 43 is not in contact with the pattern portion 23. When the operating portion 33 of the switch 3 is bent downward by the user or by another force, the air pocket
21 is compressed and the conductive portion 43 contacts the pattern portion 23. The contact between the conductive portion 43 and the pattern portion 23 completes the circuit between the pattern portions 23.

FIG. 5 shows a method of manufacturing the input / output device of this embodiment. Circuit board 7 is manufactured and packaged in a conventional manner in step 210. The membrane 13 is manufactured by the following steps 220-240. In step 220, the conductive elastomer used for the conductive portion 43 of the switch 3 is placed in the nest area of the membrane mold (mold for molding the membrane). Next, in step 230, an insulating elastomer such as silicone rubber is placed in the membrane mold. When the membrane mold is heated in step 240, the conductive elastomer is chemically and mechanically bonded to the insulating elastomer. The insulating elastomer forms the light transmitting portion 35, the operating portion 33, the post 17, and the rest of the membrane 13.

The membrane 13 is attached to the circuit board 7 by inserting the post 17 into the opening 19 (FIG. 2) in step 250. In step 260, the frame 27 is manufactured using a resin transfer molding technique as is conventional. Step
At 270, by inserting the tabs 15 of the circuit board 7 into the retaining snaps 58 of the frame 27, the frame 27 is inserted into the membrane 13 and the circuit board 7.
Attached to. Optical transmission part 35 and operation part of membrane 13
33 are inserted into the openings 55 and 53 of the frame 27, respectively. The overlay is conventionally manufactured using resin transfer molding techniques in step 280. At step 290, overlay 29 is secured to frame 27 by engaging tabs 66 of overlay 29 with slots 56 of frame 27. The optical transmission unit 35 and the operation unit 33 of the membrane 13 are overlay 29 respectively.
Through the openings 65 and 63.

[0020]

[Brief description of drawings]

FIG. 1 is an isometric view of an input / output device according to an embodiment of the present invention.

FIG. 2 is an exploded view of the input / output device according to the embodiment of this invention.

3 is a partial cross-sectional view of the lamp and switch of the input / output device of the embodiment of the present invention, taken along the line AA of FIG.

4 is an enlarged view of a lamp and a switch of the input / output device according to the embodiment of the present invention, taken along the line BB of FIG.

FIG. 5 is a flowchart showing a method of manufacturing the input / output device according to the embodiment of the present invention.

[Explanation of symbols]

 1: Panel 3: Switch 5: Lamp 7: Circuit board 13: Membrane 15: Tab provided on circuit board 7 17: Post 13 of membrane 13; Opening 21: Air pocket 23: Pattern part of switch 3 25: Lamp 5 27: Frame 29: Overlay 33: Switch 3 operation part 35: Lamp 5 light transmission part 43: Switch 3 conductive part 53, 55: Frame 27 opening 56: Frame 27 slot 58: Frame 27 retention snaps 63, 65: Overlay 29 opening 66: Overlay 29 tab 69: Textual information 100: Electronic heartbeat recorder 210-290: Manufacturing steps

Claims (11)

[Claims] 1. An input / output device (1) having a lamp (5) and a switch (3), comprising a light emitting part (25) of the lamp and first and second pattern parts (23) of the switch. A circuit board (7) including: a continuous membrane (13) made of an elastic material extending on the light emitting portion and the first and second pattern portions; and a membrane capable of passing light from the light emitting portion. An optical transmission section (35) formed on the membrane, and a switch operation section (3 formed on the membrane.
3), and an input / output device (1) comprising a conductive portion (43) formed on the membrane, which is capable of short-circuiting the first and second pattern portions when the operating portion is bent. ). 2. The input / output device according to claim 1, wherein the continuous membrane is silicon rubber. 3. The input / output device according to claim 1, wherein the continuous membrane is semitransparent. 4. The input / output device according to claim 1, wherein the continuous membrane is transparent. 5. The input / output device according to claim 1, wherein the light emitting unit is a light emitting diode. 6. The light emitting unit is an electroluminescent device.
The input / output device described in. 7. The input / output device according to claim 1, further comprising a frame (27) extending above the continuous membrane, the frame being a first frame for the optical transmission unit. Opening (5
An input / output device having 5) and a second opening (53) for the operating section. 8. The input / output device according to claim 7, further comprising an overlay (29) extending on the frame,
The said overlay has an input / output device which has the 3rd opening part (65) for the said optical transmission part, and the 4th opening part (63) for the said operation part. 9. The input / output device according to claim 1, which can be used to operate an electronic device. 10. The input / output device according to claim 9, wherein the electronic device is an electrocardiograph (100). 11. A method for manufacturing a membrane (13) of an input / output device (1) for an electronic device, the method comprising a step of inserting a conductive elastomer into a nest portion of a membrane mold, wherein the membrane mold is made of an insulating material. Adding an elastomer; heating the membrane mold to melt the conductive elastomer and the insulating elastomer to form the membrane; the insulating elastomer causes the light transmission section (35) of the lamp (5). And a step of forming an operating portion (33) of the switch (3), and a step of forming a conductive portion (43) of the switch with the conductive elastomer.