JP2000071067A - Electric soldering iron with antistatic function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To limit abnormal current caused from potential difference between an iron tip and semiconductor parts by preventing the occurrence of leak voltage by grounding the tip of an electric soldering iron via resistance of a specified value. SOLUTION: This tip 1 of an electric soldering iron is grounded via a resistance 6 of 1 MΩ. This makes it possible to prevent the occurrence of leak voltage and moderate the damping time of charges. To avoid the effect of a heater 2, the resistance 6 is contained in a holder 3 which is not in contact with the heater 2. If the iron tip 1 is grounded with 1 MΩ, very small leak voltage occurs, but it is not so strong as to destroy the semiconductor parts. If the iron tip 1 is grounded with 1 MΩ, abnormal current does not occur and the semiconductor parts are not destroyed because the charge damping factor per unit time is small. The semiconductor parts mounted on a printed circuit board charged are also charged and static electricity occurs but no abnormal current is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an electric soldering iron. In particular, the present invention relates to an electric soldering iron for preventing destruction of a semiconductor component due to static electricity.

[Prior art]

FIGS. 2 and 3 show a conventional technique of an electric soldering iron.
The configuration will be described with reference to FIG.

FIG. 2 is a configuration diagram of a conventional soldering iron. In the electric soldering iron of FIG. 2, since the tip 1 is not grounded, a leak voltage is generated at the tip 1 as shown in a voltage waveform 7c of FIG. MOS FET
When the tip of the leak voltage is brought into contact with a semiconductor component having a low withstand voltage, such as the above, dielectric breakdown may occur due to a potential difference between the two, which may cause failure such as breakdown of the semiconductor component or deterioration of characteristics. .

In the electric soldering iron shown in FIG. 3, a tip 1 is grounded by a ground wire 5. Therefore, the voltage waveform 7b of FIG.
As described above, the leak voltage of the tip 1 is discharged.

[0005]

However, the electric soldering iron shown in FIG. 3 is designed to prevent the occurrence of leakage voltage.
No measures are taken against the generation of static electricity. That is, the semiconductor components mounted on the charged printed circuit board are also charged. In this state, if the tip is brought into contact with the lead of the semiconductor component, an abnormal current is generated due to the potential difference between the two, causing troubles such as destruction of the semiconductor component and deterioration of characteristics.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems by preventing the occurrence of a leak voltage, limiting an abnormal current caused by a potential difference between a soldering iron tip and a semiconductor component.

[0007]

According to the first aspect of the present invention, an electric soldering iron tip is grounded via a resistor.

According to a second aspect of the present invention, in the first aspect, the resistor 6 is built in the holder 3.

The invention according to claim 3 is based on claims 1 and 2
In the invention described in any one of the above items, the resistance 6 is 1 MΩ.

[0010]

Next, an embodiment of an electric soldering iron according to the present invention will be described with reference to the drawings. FIG.
1 is a configuration diagram illustrating an electric soldering iron according to an embodiment of the present invention.

In FIG. 1, an electric soldering iron 1
Is grounded via a 1 MΩ resistor 6. Therefore, generation of a leak voltage can be prevented as shown in a voltage waveform 7a in FIG. 4 described later, and the decay time of the electric charge can be made slow like a voltage waveform 8a in FIG. 5 described later. Also,
In the present embodiment, a resistance value of 1 MΩ is used.
This is an example for limiting the abnormal current, and other resistance values may actually be used.

Further, in FIG. 1, a 1MΩ resistor 6
Is stored in the holder 3 without contact with the heater 2 in order to avoid the influence of heat from the heater 2.

FIG. 4 shows that the resistance between the tip and the power supply ground is
It is a figure showing the leak voltage of a tip at the time of 0 (ohm) * 1M (ohm) * (ohm). In FIG. 4, a voltage waveform 7a in which the tip and the ground are connected by a resistance of 1 MΩ has a smaller leak voltage than a voltage waveform 7c in which the tip is not grounded. However, the semiconductor component is not destroyed due to the leak voltage. Further, since the voltage waveform 7b having the tip 1 grounded is discharged, no leak voltage occurs.

FIG. 5 is a diagram for explaining the charge decay state when the resistance value between the tip and the power supply ground is 0Ω / 1MΩ∞Ω. In FIG. 5, the voltage waveform 8a corresponds to the tip 1
A voltage waveform 8b is a waveform in which the tip 1 is grounded by the tip grounding wire 5 and a voltage waveform 8b. Since the voltage waveform 8a has a small amount of charge decay per unit time, no abnormal current is generated and the semiconductor component is not destroyed. However, since the voltage waveform 8b has a large amount of charge decay per unit time, an abnormal current that may destroy the semiconductor component may occur. The voltage waveform 8c does not discharge because the tip 1 is not grounded although the charge moves.

[0015]

According to the present invention, in order to prevent the occurrence of a leak voltage at the tip and to control the charge decay time, it is possible to prevent the destruction of semiconductor components and the deterioration of characteristics, and to add a 1 MΩ resistor in the holder. In this case, there is an effect that it can be used without impairing the workability.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of an electric soldering iron according to the present invention.

FIG. 2 is a configuration diagram of an electric soldering iron having an ungrounded iron tip according to the related art.

FIG. 3 is a configuration diagram of an electric soldering iron with a grounded tip according to the prior art.

FIG. 4 shows that the resistance value between the tip and the power supply ground is 0Ω · 1MΩ.
It is a figure showing the leak voltage of a tip at the time of ∞Ω.

FIG. 5 shows that the resistance value between the tip and the power supply ground is 0Ω · 1MΩ.
FIG. 4 is a diagram for explaining a state of charge decay at ΔΩ.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Iron tip 2 Heater 3 Holder 4 Heater power supply line 5 Iron tip ground wire 6 Resistance 7a Voltage waveform 7b Voltage waveform 7c Voltage waveform 8a Voltage waveform 8b Voltage waveform 8c Voltage waveform

Claims (3)

[Claims] 1. An electric soldering iron with an antistatic function, wherein the tip of the electric soldering iron is grounded via a resistor. 2. The electric soldering iron with an antistatic function according to claim 1, wherein said resistor is built in a holder. 3. The electric soldering iron with an antistatic function according to claim 1, wherein the resistance is 1 MΩ.