JPS60205622A - Preventing device of electrostatic noise - Google Patents

Abstract

PURPOSE:To prevent the malfunction of equipment due to electrostatic discharge at extremely low cost by providing a switch consisting of a contacting part made of a conductive material and a contact which is made through the operation of the contacting part and grounds the contacting part through a current limiting resistor. CONSTITUTION:An operator holds an electric pen and presses the push button 4a of a switch 4 for electrostatic discharge prior to input operation, and then charges (accumulated charge in capacitor 21) that the operator has flow to an earth terminal through a resistance 22, the switch 4, and the discharging current limiting resistor 5 because the contact 4 is made. The quantity of electricity during the discharge is suppressed by the resistor 5 and the discharging current path is independent of an electronic circuit 3 which functions as the electric pen, so there is no influence upon an input device itself. Further, the discharge is caused at the contact 4b, so the operator has neither a shock nor pain.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a device for preventing noise caused by electrostatic discharge in electronic equipment, such as computer terminal equipment.

[Prior art]

Currently, most computer rooms, CAD rooms, OA rooms, etc. have carpeted floors and are air-conditioned independently of the outside air in order to improve dustproofing, soundproofing, and air-conditioning effects.

Therefore, the relative humidity indoors becomes extremely low as the room temperature rises due to heating, heat radiation from various devices, etc. (This tendency is particularly noticeable in eastern Japan during the winter,
% or even less).

As a result, the human body can easily generate high voltages when driving indoors in low humidity, when working, causing friction between clothes, when shoes or slippers rub against floor materials, and even between paper and paper, or between paper and desks. is charged with electricity. When a charged operator operates a terminal device, electrical discharge may occur on the ground wire of various coordinate and command input devices such as keyboards, light rails, tablets, etc., and the cases of various other terminal devices, causing malfunctions in these electronic devices. At the same time, the operator feels shock and pain due to electrical discharge from the fingers and the like upon contact.

For this reason, conventional methods have been to lower the impedance by making the ground wire of the printed wiring board thicker on the terminal equipment side, by grounding the entire surface of the multilayer printed wiring board, and by installing bypass capacitors on the printed wiring board to improve noise resistance. In addition to taking measures such as using elements with high noise resistance in the circuit used, removing carpet from the floor or replacing it with a conductive one, or spraying antistatic agent, and measures such as increasing indoor humidity by sprinkling water or installing humidifiers.

These countermeasures are intended to prevent the generation of static electricity itself and to increase the noise resistance of the device itself, but all of them are expensive to implement and require a huge amount of money. I have not found anything that can completely prevent malfunctions.

[Object and structure of the invention]

The present invention has been made in view of these circumstances.
The purpose is to provide an electrostatic noise prevention device that can easily implement static electricity countermeasures at a much lower cost than conventional methods.

In order to achieve such an object, the present invention includes a contact portion made of a conductive material, and a contact portion that is closed by operation of the contact portion and connects the contact portion to a ground terminal via a current limiting resistor. It is equipped with a switch consisting of contacts.

In other words, rather than trying to suppress the generation of static electricity itself, it is discharged during operation through a path that does not affect the terminal device itself, thereby preventing malfunction of the terminal device and reducing shock to the operator. , which removes pain.

Hereinafter, the present invention will be described in detail using the illustrated embodiments. [Example] FIG. 1 is a block diagram showing an embodiment in which the present invention is applied to an electric pen, which is a type of coordinate input device. In the figure, a push button 2 for an input switch is provided on the outside of a bent-shaped case 1, and an input electronic circuit 3 connected to this switch is provided inside, and this circuit 3 is the main body of the input device (not shown). The connection to the pen is similar to that of a normal electric pen, but in this embodiment, an electrostatic discharge switch 4 and a discharge current limiting resistor 5 are further provided.

As shown in FIG. 2, the electrostatic discharge switch 4 is a non-rotating pushbutton that is entangled with a pushbutton 4a made of a conductive material that protrudes from the outside of the case 1 and a contact 4b that is closed when the pushbutton 4a is pressed. Button switch, contact 4b
When the button is closed, a series circuit is formed from the push button 4a to the ground terminal GND via the resistor 5, and the electric charge Q on the human body flows to the ground terminal.

That is, in FIG. 2, reference numeral 10 indicates the noise prevention device of this embodiment, and reference numeral 20 indicates the equivalent circuit of the operator.
When pressing a, the electric charge charged on the operator and the electric charge Q accumulated in the capacitor 21 (capacitance value C at the time of discharge) are changed to the resistance 22 (resistance value Rz) because the contact 4b is closed.
and flows through switch 4 and resistor 5 to the ground terminal. The amount of current during discharge is suppressed by the resistor 5 (resistance value Rl), and the discharge current path is a completely separate circuit from the electronic circuit 3 that performs the original function of the electric pen as described above. It has no effect on the device itself. Further, since the discharge occurs at the contact point 4b, the operator himself does not experience any shock or pain.

By pressing the discharge switch 4 in this manner, the operator's electric charge is eliminated, so that by performing normal input operations thereafter, inconveniences such as malfunctions caused by electrostatic discharge can be completely avoided.

Similar coordinate and command input devices include a mouse, a tablet used in particular in a CAD system, and other input devices that are directly held by the operator to perform input operations. Coordinate and command input devices are applicable in the same way as , but such coordinate and command input devices must be picked up by the operator when performing input operations, and in that sense, they do not require special consciousness or movement. It can be said that this device is particularly suitable for implementing the present invention in that the electrostatic discharge valve button switch can be touched and the electrostatic charge can be discharged without touching the electrostatic discharge valve button switch.

Similarly, when an operator operates a terminal device, it is effective to first sit down on a chair, then bring the arm to the operating table, and then place the terminal device in an armrest placed in the position that is most convenient for the dominant arm. FIG. 3 is a configuration diagram showing an embodiment in which the present invention is applied to such an arm rest. In the figure, arm rest 3
1 is made of a somewhat flexible conductive material and is connected to the ground terminal GND via the NC contact of a discharge current limiting resistor 32 and a microswitch 33.

When the operator places his or her arm on it, the weight of the arm rests on the arm rest 31.
flexes, the NC contact closes to push the actuator of the microswitch 33, and the electric charge on the human body is transferred to the NC of the arm rest 31, the resistor 32, and the microswitch 33.
It is released through the contact to the ground terminal. As described above, the amount of current is suppressed by the resistor 32, and the discharge current path can be a completely separate circuit from the internal circuit of the terminal device that the operator is trying to operate, so that it does not affect the terminal device at all. It is possible to eliminate the electrostatic charge without giving any. Similarly, since the discharge occurs at the NC contact, there is no shock or pain to the operator. When the arm is released, the arm rest 31 and the microswitch 33 are restored to their initial state due to the action of the spring 340, and the operator no longer has to worry about the malfunction of the terminal device or physical pain caused by electrostatic discharge. You can operate it with confidence.

Also, as a result of getting into the habit of placing your arm on the arm rest 31 while you are not operating the keyboard of the terminal device, you will not be able to rest your arm and will be able to move quickly the next time you operate the keyboard etc. Ru. It also has the advantage of becoming

As described above, both the first and second embodiments are preferable in that the touching operation on the contact portion made of a conductive material can be performed extremely easily before the terminal device is used, and can also be easily performed at any time during use of the terminal device. However, the embodiment of the present invention is not limited to this, and can be freely incorporated into other terminal devices.For example, FIG. 4 shows an embodiment when applied to a printer. An electrostatic discharge switch push button 41 is provided in front of the operation keypad 41 in a position where the operator can easily place his/her hand. Of course, a discharge current limiting resistor is provided inside, and when the operator presses the push button 41 to close the contact of the switch, the resistor is connected from the human body to the ground terminal in series. A circuit is formed and the electrostatic charge is released.Other methods include installing independent electrostatic noise prevention devices in several locations in the room, completely unrelated to the various terminal devices, unless you are willing to go to the trouble of going to the contact points. You can also take

〔Effect of the invention〕

As explained above, according to the present invention, a contact portion made of a conductive material, a current limiting resistor, and a contact portion that closes when a contact operation is performed to ground the contact portion through the resistor. With a simple configuration consisting of a contact connected to a terminal, it is possible to prevent malfunction of electronic equipment due to electrostatic discharge at a very low cost, and a humidifier or other expensive electrostatic generation prevention treatment device is not required. In addition, it eliminates the shock and pain that occurs when electrical discharge occurs from the human body, and also has a great mental health effect by freeing the operator from anxiety and tension about when the electrical discharge will occur.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is an equivalent circuit diagram thereof, and FIGS. 3 and 4 are block diagrams showing other embodiments of the present invention. 1... Electric pencil case, 4... Electrostatic discharge switch, '4a, 41-... Push button (contact part), 4
be...Contact, 5.32...@discharge current limiting resistor, 31...Arm rest (contact part), 33...Micro switch. Patent Applicant Yamatake Honeywell Co., Ltd. Agent Masaki Yamakawa (2 persons) Figure 1 Figure 2 Figure 3 Moe Figure 4 ND Procedural Amendment (Mackerel) 1. Indication of the case 1982 Patent Application No. 59483 2 , Name of the invention Electrostatic noise prevention device 3, Relationship with the case of the person making the amendment Patent Name of applicant (name) (666) Yamatake Honeywell Co., Ltd. 5,
System to be amended (1) The scope of claims in the specification shall be amended in a separate document. (2) "Tablet" on page 6, line 17 of the specification is corrected to "electric pack." Attachment ``(1) A contact part made of a conductive material, a current limiting resistor, and a contact part that closes when a contact operation is made and connects the contact part to a ground terminal via the current limiting resistor. An electrostatic noise prevention device comprising a contact to be connected. (2) An electrostatic noise prevention device according to claim 1, wherein the contact portion constitutes an arm rest. (3) Contact The electrostatic noise prevention device according to claim 1, wherein the part is a push button provided on a coordinate and command input device having a grip part. (4) The coordinate and command input device is an electric The electrostatic noise prevention device according to claim 3, characterized in that it is a pen. (5) The electrostatic noise prevention device according to claim 3, characterized in that the coordinate and command input device is an electric pack. Electrostatic noise prevention device.”

Claims (1)

[Claims] (13) A contact portion made of a conductive material, a current limiting resistor,
An electrostatic noise prevention device comprising: a contact that closes when the contact portion is operated to connect the contact portion to a ground terminal via a current limiting resistor. (2) The electrostatic noise prevention device according to claim 1, wherein the contact portion constitutes an arm rest. (3) The electrostatic noise prevention device 0 according to claim 1, wherein the contact portion is a push button provided on a coordinate and command input device equipped with a grip portion. (4) Coordinate and 4. The electrostatic noise prevention device according to claim 3, wherein the command input device is an electric pen. (5) The electrostatic noise prevention device according to claim 3, wherein the coordinate and command input device is a tablet.