Patent Application
20200214117
The present invention is related to removing of static electricity, and in particular to a wearable static electricity removing device
In electronic factories, or in dry areas, large static electricity possibly generates and is accumulated. Large static electricity will generate surge power to hurt the users or destroy devices. Therefore, it is necessary to remove the static electricity.
A ring, such as wristband or bracelet or leg band or leg ring, is used to remove static electricity. In these devices, one end has a conductive wire 40′which is grounded and another end thereof is a metal sheet 10′which contacts bodies of users. The conductive wire 40′is serially connected to a resistor 30 of 1 Ω, see
Because the manufacturing process of semiconductor will enter into a process of 5 nanometers, and thus the elements under these process are more and more sensitive to the static electricity. The ability of HBM endurance for IC components is reduced from 4 kV to 500V. Thereby, the ability to prevent the static electricity is an important consideration for IC manufacturing and packaging. Furthermore for RF components or other static electricity sensitive components, they are easily to be destroyed even the voltage of the static electricity is under 50V. As a result, the conventional static electricity preventing rings are not sufficient to protect the operator or the components from impacting of the static electricity.
Accordingly, to overcome the defect in the prior art as above said, the present invention provides a wearable static electricity removing device, in that a portable device is installed with a metal sheet. A high impedance resistor and a current limiter are connected to the metal sheet in parallel. The high impedance resistor and the current limiter are connected to a conductive wire which is grounded. An electric static suppression element (such as a TVS diode) may be connected between the metal sheet and the current limiter so as to remove static electricity at human body quickly with a very low residue voltage of about 7V, which does not destroy electronic devices. The structure of the present invention can achieve the effects of protecting users and avoiding residual current to destroy peripheral devices. Furthermore when the user contacts higher voltage, the current limiter will break to protect the user, while the current can flow through the high impedance resistor. If the current is too high, the high impedance resistor may burn out to further protect the user. In the present invention, the LED lamp set can be connected between the electric static suppression element and the current limiter. The light of the LED lamps can show the charge to be positive or negative and the effect of removing the static electricity.
To achieve above object, the present invention provides a wearable static electricity removing device, comprising: a portable device including: a metal sheet for contacting a user's body wearing the portable device; a current limiter for limiting a current flow therethrough; If a predetermined value of current is over, the current limiter will open to cause a circuit having the current limiter to be opened; the current limiter having a left end connected to the metal sheet; a high impedance resistor having a left end connected to the metal sheet; an impedance of the high impedance resistor being greater than that of the current limiter; a conductive wire having a left end connected to a right end of the current limiter and a right end of the high impedance resistor; and a right end of the conductive wire being grounded; therefore, the current limiter and the high impedance resistor being connected parallel between the metal sheet and the conductive wire. In use, the portable device is worn on the body of the user and the metal sheet is in contact to the body of the user; when the body of the user has static electricity, the static electricity will pass through the current limiter and then flows to the ground through the conductive wire so as to have the effect of removing the static electricity. When the user contacts a predetermined high voltage which causes the current limiter to breakdown to protect the user from getting electrically shocked, and the static electricity from the user flows through the high impedance resistor and then to the conductive wire for discharging to ground.
In order that those skilled in the art can further understand the present invention, a description will be provided in the following in details. However, these descriptions and the appended drawings are only used to cause those skilled in the art to understand the objects, features, and characteristics of the present invention, but not to be used to confine the scope and spirit of the present invention defined in the appended claims.
With reference to
A portable device I comprises the following elements. A metal sheet 10 serves to contact a user's body wearing the present invention.
A current limiter 20 serves to limit the current flow therethrough. If a predetermined value of current is over, the current limiter will open to cause a circuit having the current limiter to be opened. The current limiter has a left end connected to the metal sheet 10. Preferably, the current limiter 20 breaks at a current smaller than or equal to 0.4 A. Generally, the resistance of the current limiter 20 is smaller than 0.6 Ω. In the following, a fuse is used as an example of the current limiter, however this is not used to confine the scope of the present invention, other elements have the same effect are useable in the present invention and are within the scope of the present invention.
A high impedance resistor 30 has a left end connected to the metal sheet 10. An impedance of the high impedance resistor 30 is greater than that of the current limiter 20. Preferably, a resistor of the high impedance resistor 30 is 1 MΩ. The high impedance resistor 30 can bear a current of 0.5 A.
A conductive wire 40 has a left side connected to a right end of the current limiter 20 and a right end of the high impedance resistor 30. A right end of the conductive wire 40 is grounded.
Therefore, the current limiter 20 and the high impedance resistor 30 are connected parallel between the metal sheet 10 and the conductive wire 40. An electric static suppression element 50 is connected between the current limiter 20 and the metal sheet 10, see
The portable device 1 is worn on the body of the user and the metal sheet 10 is in contact to the body of the user. A right end of the conductive wire 40 is grounded. When the body of the user has static electricity, because the resistances of the electric static suppression element 50 and the current limiter 20 are lower than that of the high impedance resistor 30, the static electricity will pass through the electric static suppression element 50 and the current limiter 20 and then flows to the ground through the conductive wire 40 so as to have the effect of removing the static electricity.
With reference to
Each of the TVSs 61, 62 has a working voltage, a breakdown voltage, and a clamping voltage between the working voltage and the breakdown voltage. Each of the TVS diode has a parasitic capacitor and has directivity and each of the TVS diode is an unidirectional transient voltage suppression.
When the user's body has positive static electricity, the static electricity will flow through the metal sheet 10, the forwardly connected
TVS diode 61 and the conductive wire 40 to ground. Similarly, when the user's body has negative static electricity, the static electricity will flow through the current limiter 20, the reversely connected TVS diode 62 to the body so as to remove the static electricity in the body of the user. The activation speed of the TVS diodes 61, 62 are smaller than 0.1 μs, while in general, a duration for discharging of static elections is smaller than 0.1 μs. Therefore, once the user's body has static electricity, they will be bypassed to the grounds almost at the same time. Furthermore, the present invention can be used to protect the user when the user gets electric shock at a high voltage.
Preferably, the working voltage of the TVS diode is 5V, and the breakdown voltage is 8V. When the electric static voltage is higher than the breakdown voltage of the TVS diodes 61, 62, the TVS diodes 61, 62 will be actuated and at this moment, the internal resistors of the TVS diodes 61, 62 are about 0.1 Ω and the electric static voltage is clamped at about 7V. That is to say, by using the static electricity removing device of the present invention, the static electricity can be conducted to ground at a very short time, about 0.1 μs. Therefore, the user does not worry about that the residual electric charges in his or her body will destroy static electricity sensitive IC components. However, conventional static electricity removing rings with a 1 MΩ resistor have residual charges of several hundred voltages. The static electricity removing device according to the present invention may control the static electricity voltage at a very low value of about 7V. The effect is improved greatly. In the present invention, the endurance current of the current limiter 20 is equal to or smaller than 0.4 A. When a user contacts a very high voltage, such as 110V to 330V, carelessly, the current limiter 20 breaks so that the circuit is opened to protect the user from being hurt electrically. At this moment, the static electricity can flow through the high impedance resistor 30 to the conductive wire 40 to remove the static electricity. Thus dual circuits for removing static electricity have a better effect in removing static electricity. When the current flow continuously or over 0.5 A, the high impedance resistor 30 will burn up to cause the circuit is opened to protect the user from being hurt by high voltage. With reference to
With reference to
The bidirectional TVS diode 63 has a working voltage (Vrbw) and a breakdown voltage. The bidirectional TVS diode 63 has a parasitic capacitor.
Referring to
The unidirectional TVS diodes 61, 62, 64 and the bidirectional TVS diode 63 have parasitic capacitance, and furthermore, thee can be passed by positive and negative charges. When a user wears the portable device 1, the value of the static electricity is very low. If we measure the resistances of the TVS diodes 61, 62, 63 and 64, they have the property of capacitors and are opened. When a user has static electricity, the static electricity flows from the metal sheet 10 to the TVS diodes 61, 62, 64, or the bidirectional TVS diode 63. When the voltage of the static electricity is higher than the breakdown voltages of the TVS diodes 61, 62, 64 or the bidirectional TVS diode 63 (for example, 8V, based on the TVS diode used), the TVS diodes 61, 62, 64 and 63 will conduct at a time period about 0.1 μs. Because interior resistors of the TVS diodes 61, 62, 63 and 64 are smaller than 0.1Ω, and thus the static electricity current flows through the TVS diodes 61, 62, 63 and 64 and then through the current limiter 20 and the conductive wire 40 to the ground in a very short time (0.1 μs). The TVS diodes 61, 62, 63 and 64 have clamping voltages, and thus high static voltage (such as several decades KV) are conducted transiently (at a time period of 0.1 μs), while the electron static voltage of the metal sheet 10 is clamped at a value about 7V. The clamping voltage is determined by the property of selected TVS diodes. Preferably, the dynamic impedances of the TVS diodes 61, 62, 63 and 64 are smaller than 0.1 which can present a better effect. By experiments, the TVS diodes and current limiter 20 may suffer from an electric static impact 30 KV and do not burn up. If DC or AC current is near 0.4 A, the current limiter 20 will burn up. In conduction, the unidirectional TVS diodes 61, 62, 64 or the bidirectional TVS diode 63 has an inner impedance of 0.1 Ω, and the inner impedance of the current limiter 20 is small than 0.6Ω. The total impedance is smaller than 0.7 Ω which is very smaller than nu) impedance of the high impedance resistor 30. Therefore, in general, the electric static current flows along the path having the TVS diodes to cause the electric static current is removed very quickly.
The electric static suppression element 50 may be a varistor, a Zener diode or a polymer suppressor. In the present invention, the TVS diodes have better effect in suppressing of static electricity, because they have a quick response, low internal resistors after actuation, high endurance for static electricity, etc.
With reference to
With reference to
With reference to
Preferably, the LED lamps 71, 72 have highly intensities and can bear large current so as to bear high static electricity, for example, to bear an Electrostatic Discharge (ESD) to 20 kV-30 kV. If the LED lamp set is a general one, a small resistor 80 (referring to
With reference to
With reference to
The portable device 1 is a wristband 100 (see
In the present invention, a portable device is installed with a metal sheet. A high impedance resistor and a current limiter are connected to the metal sheet in parallel. The high impedance resistor and the current limiter are connected to a conductive wire which is grounded. An electric static suppression element (such as a TVS diode) may be connected between the metal sheet and the current limiter so as to remove static electricity at human body quickly with a very low residue voltage of about 7V, which does not destroy electronic devices. The structure of the present invention can achieve the effects of protecting users and avoiding residual current to destroy peripheral devices. Furthermore when the user contacts higher voltage, the current limiter will break to protect the user, while the current can flow through the high impedance resistor. If the current is too high, the high impedance resistor may burn out to further protect the user. In the present invention, the LED lamp set can be connected between the electric static suppression element and the current limiter. The light of the LED lamps can show the charge to be positive or negative and the effect of removing the static electricity.
The present invention is thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
