JPH0742096U - Static eliminator - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain a safe static eliminator with excellent static erasing performance. [Structure] Since the tip of the discharge electrode 14 projects about 1 mm from the bottom surface 25t1 of the recess formed in the bottom surface of the ground electrode 25, excellent static elimination performance verified by experimental data is obtained. On the other hand, since it does not project from the bottom surface 25t2 that sandwiches the concave portion, the needle-shaped discharge electrode 14 does not project from the static elimination electrode 12 ', and there is no risk of damaging a charged object opposite thereto. Further, there is no concern that the discharge electrode 14 itself will be damaged.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a static eliminator that eliminates static electricity from an object.

[0002]

[Prior art]

 Since semiconductor devices are easily destroyed by static electricity, it is necessary to eliminate static electricity during storage and manufacturing processes. Therefore, conventionally, for example, a static eliminator as shown in FIG. 7 has been used in the manufacturing process of the semiconductor device. In FIG. 7, 10 is a power supply device, which is composed of a commercial AC power supply (100V) 1, a power supply switch 2, and a step-up transformer 3. Reference numeral 12 denotes a static elimination electrode, which is connected to the power supply device 10 by a coaxial cable 11.

Next, the configuration of the static elimination electrode 12 will be described with reference to the figure (FIG. 8) showing the specific structure thereof. In FIG. 8, (A) is a front view, and (B) is a cross-sectional view in the X-X ′ direction of the front view (A). As shown in FIGS. 7 and 8, a predetermined length at the tip of the central conductor portion of the coaxial cable 11 is used as the high voltage electrode 13. Next, reference numeral 17 in FIG. 8 is a coupling ring formed of an insulating material in a hollow cylindrical shape, the surface of which is covered with a conductor such as brass. A needle-shaped discharge electrode 14 projects from the conductor.

A plurality of the coupling rings 17 are provided at predetermined intervals, and the hollow portion thereof is penetrated by the high-voltage electrode 13 covered with the insulating coating 16. That is, the high voltage electrode 13 and each discharge electrode 14 are capacitively coupled via the above-mentioned insulating portion. Further, reference numeral 18 is a mold portion that covers each coupling ring 17 from which the high voltage electrode 13 and the discharge electrode 14 project. Numeral 19 is another mold part provided so as to cover the mold part 18. The ground electrode 15 is fixed in the form as shown in FIG. 8 and also has a role of integrally protecting the static elimination electrode 12. I carry it.

In the above configuration, it is assumed that a charged object is placed below the static elimination electrode 12 in a non-contact state with the static elimination electrode 12, and the power switch 2 is turned on. As a result, the output voltage of the power source 1 is boosted to, for example, 7 kV via the boosting transformer 3, and a low-frequency high voltage is applied to the high-voltage electrode 13 via the coaxial cable 11. Then, a corona discharge is generated between the discharge electrode 14 capacitively coupled to the high-voltage electrode 13 and the ground electrode 15, and the air around the static elimination electrode 12 is alternately ionized into positive ions and negative ions. Then, ions of either polarity are attracted to the charged object depending on the polarity of the charged charge of the charged object, recombine with the charged charge of the charged object, and the charged charge is neutralized. By the way, as shown in FIG. 8, the discharge electrode 14 and the ground electrode 15 are arranged such that the tip of the discharge electrode 14 slightly protrudes from the bottom surface 15 a of the ground electrode 15. It has been conventionally known that such a form is advantageous for increasing discharge efficiency.

[0006]

[Problems to be solved by the device]

 However, in the above-described configuration, the needle-shaped discharge electrode 14 projects from the static elimination electrode 12, so that there is a risk of damaging the charged object facing the static elimination electrode 12. Moreover, there is a concern that the discharge performance may be impaired due to breakage or wear of the discharge electrode 14 itself. That is, it cannot be said that the form is excellent in safety. The present invention has been made in view of such circumstances, and an object thereof is to provide a safe static eliminator having excellent static erasing performance.

[0007]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention has a step-up transformer whose primary side is connected to an AC power source, a discharge electrode coupled to one end of the step-up transformer secondary side, and a discharge electrode facing the discharge electrode. And a grounding electrode connected to the other end on the secondary side of the step-up transformer and connected to both electrodes in a non-contact manner to remove a charge of a charged object. It is characterized in that a recess is provided on the surface of the electrode facing the charged object, and the tip of the discharge electrode projects from the recess and does not project from the peripheral portion of the recess.

[0008]

[Action]

 According to the above configuration, since the tip of the discharge electrode projects from the recess provided on the surface of the ground electrode facing the charged object, good static elimination performance is obtained, and the tip projects from the peripheral portion of the recess. Since it does not, there is no danger of damaging the charged object or the discharge electrode, and it is safe.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. The basic configuration of the static eliminator in this embodiment is the same as that shown in FIG. Here, instead of the static elimination electrode 12 shown in FIG. 8, the static elimination electrode 12 'shown in FIG. 1 is used. In FIG. 1, (A) is a front view and (B) is a cross-sectional view taken along line XX ′ in the front view (A). The static elimination electrode 12 'shown in FIG. 1 is different from the static elimination electrode 12 shown in FIG. 8 only in the shape of the ground electrode and the shape of the mold portion to which the ground electrode is fixed, which will be described below. It is the same as this.

The ground electrode 25 in the static elimination electrode 12 'is formed by arranging the electrode members 25a and 25b formed in a stepwise shape in the opposite direction with a distance of about 10 mm as shown in FIG. 1B. A recess is formed on the bottom surface of the ground electrode 25 (that is, also the bottom surface of the static elimination electrode 12 ′). The tip of the discharge electrode 14 projects from the bottom surface 25t1 of the recess by about 1 mm, but does not project from the bottom surface 25t2 sandwiching the recess.

Next, an experiment conducted by the inventor of the present application in order to confirm the validity of the static eliminator having such a form will be described. In this experiment, the performance of the experimental static eliminator, which was obtained by modifying the above static eliminator for experiments, was examined by using the static eliminator performance test system described later. <Experimental static eliminator> FIG. 2 is a diagram showing the structures of the discharge electrode and the ground electrode in the experimental static eliminator. As shown in FIG. 2, in the experimental static eliminator, the ground electrode 22 was used in place of the ground electrode 25 shown in FIG. The ground electrode 22 includes electrode members 22a and 22b whose ends are bent in an L shape and an inverted L shape, and are opposed to each other with the discharge electrode 14 interposed therebetween. Although illustration is omitted, the relative position of the discharge electrode 14 and the ground electrode 22 is improved by devising the shape of the mold part 19 shown in FIG. 1 and the fixing method of the mold part 19 and the ground electrode 22. I was able to change the relationship to some extent.

Then, the following parameters were set for the ground electrode 22. -Projection length A: The height of the discharge electrode 14 when the height of the bottom surface 22t of the ground electrode 22 is "0" and the direction of the arrow y in FIG. 2 is positive. Length B: The length of the surface of the ground electrode 22 facing the discharge electrode 14. Width W: The distance between the electrode members 22a and 22b. The other parts of this experimental static eliminator are configured in the same manner as the above static eliminator (FIGS. 1 and 7). Then, the above-mentioned parameter values (that is, the shape or position of the ground electrode 22) were variously changed, the static elimination performance test described below was performed, and the results were compared.

<Static Elimination Performance Test System> FIG. 3 is a configuration diagram of an electrostatic elimination performance test system for examining the electrostatic elimination performance of the static eliminator. In FIG. 3, 12ex is the static elimination electrode of the above-mentioned experimental static eliminator, and 10 and 11 are a power supply device and a coaxial cable portion of the static eliminator, respectively. Next, 31 is a simulated charged object, which is, for example, a metal plate having a size of about 55 cm × 20 cm × 2 mm. Reference numeral 31a is a ground terminal provided on the simulated charged object 31, and a high-voltage measuring device 33 such as a DC ammeter 32 and an electrostatic voltage meter is inserted between the ground terminal 31a and the ground GND. Further, 34 is a direct current high voltage power source arranged in parallel with the high voltage measuring device 33.

In the configuration shown in FIG. 3, the static elimination electrodes 12ex are opposed to each other above the simulated charged object 31 with a predetermined distance (for example, 20 mm 2). Then, the output voltage of the DC high-voltage power supply 34 is gradually increased so that the indication value of the high-voltage measuring device 33 becomes -5 kV. Next, the power supply device 10 of the static eliminator is operated (the power switch 2 of FIG. 7 is turned on), and the indication value Ie (μA) of the DC ammeter 32 is read. Then, the current Je- (μA / cm) per unit length is obtained by the following equation (1). Je- = | Ie | / Le (1) Here, Le is the distance (cm) between the two discharge electrodes 14 that are most separated from each other in the static elimination electrode 12ex, and is called the effective electrode length.

Next, the connection of the DC high-voltage power supply 34 and the DC ammeter 32 is reversed, and the output voltage of the DC high-voltage power supply 34 is set to +5 kV by the same procedure as above. Then, from the indicated value Ie (μA) of the direct current ammeter 32 at that time, the current Je + per unit length (μA / cm) is obtained by the same calculation as the above equation (1). In this way, the smaller one of the currents Je- and Je + per unit length obtained for the cases where the potential of the simulated charged object 31 is set to -5 kV and +5 kV, the smaller one is discharged to the static elimination electrode per unit length. The current is Je. That is, it can be said that the larger the static elimination current Je per unit length is, the higher the static elimination performance is, and the better the static elimination performance is.

<Experimental Results> The data obtained by the static elimination performance test are shown below. Fig. 4 shows the test results when the protrusion length A was changed, the length B was fixed at 7 mm, the width W was fixed at 10 mm, and only the protrusion length A was changed. In the graph of FIG. 4, the horizontal axis represents the protrusion length A (mm) and the vertical axis represents the static elimination current Je (μA / cm) per unit length. From this result, excellent static elimination performance is obtained when the tip of the discharge electrode 14 is projected from the bottom surface of the ground electrode 22 by about 1 mm or more. On the contrary, on the contrary, the tip of the discharge electrode 14 is It can be seen that the static elimination performance is considerably reduced when the ground electrode 22 is recessed from the bottom surface by 2 mm or more.

When the length B is changed The protrusion length A is fixed at -1 mm, the width W is fixed at 10 mm, and only the length B is changed, and the test results are shown in FIG. In the graph of FIG. 5, the horizontal axis represents the length B (mm), and the vertical axis represents the static elimination current Je (μA / cm) per unit length as in FIG. From this result, it can be said that the length B does not particularly affect the static elimination performance.

When the width W is changed: The projecting length A is fixed to -1.3 mm, the length B is fixed to 1 mm, and only the width W is changed, and the test results are shown in FIG. In the graph of FIG. 6, the horizontal axis represents the width W (mm) and the vertical axis represents the static elimination current Je (μA / cm) per unit length as in FIGS. From this result, it can be said that the width W does not particularly affect the static elimination performance up to a certain size (about 13 mm from the graph). When the width W becomes larger than the above range, the static elimination performance gradually decreases.

From the above experimental results, it is considered that excellent discharge performance can be obtained by forming the discharge electrode and the ground electrode so that the width W is 13 mm or less and the protrusion length A is about 1 mm. It was confirmed that these conditions were satisfied for the discharge electrode 14 and the ground electrode 25 in FIG. 1, and therefore, the charge eliminator of this example provided satisfactory charge removal performance.

The method of using this static eliminator is the same as that of the above-described conventional static eliminator, and a description thereof will be omitted here. In use, in this static eliminator, since the needle-shaped discharge electrode 14 does not protrude from the static eliminator electrode 12 'due to the above-mentioned configuration, there is no danger of damaging a charged object opposite to this, and the discharge electrode There is no concern that 14 itself will be damaged. On the other hand, since the tip of the discharge electrode 14 projects from the recess provided in the ground electrode 25, the excellent static elimination performance is obtained as described above.

[0021]

[Effect of device]

 As described above, according to the present invention, the tip of the discharge electrode protrudes from the recess provided in the ground electrode, but does not protrude from the peripheral portion of the recess, which is safe and has excellent static elimination performance. A static eliminator can be obtained.

[Brief description of drawings]

FIG. 1 is a static elimination electrode 1 of a static eliminator according to an embodiment of the present invention.
It is a figure which shows the structure of 2 '.

FIG. 2 is a diagram illustrating the structure of a static elimination electrode used in a static elimination performance comparison experiment according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a static elimination performance test system used in the static elimination performance comparison experiment.

FIG. 4 is a graph showing the results of the static elimination performance comparison experiment.

FIG. 5 is likewise a graph showing the results of the static elimination performance comparison experiment.

FIG. 6 is a graph showing the results of the static elimination performance comparison experiment in the same manner.

FIG. 7 is a block diagram showing a configuration of a static eliminator according to an embodiment of the present invention and a conventional example.

FIG. 8 is a diagram showing a structure of a static elimination electrode 12 of a conventional static eliminator.

[Explanation of symbols]

 1 AC power supply 3 Step-up transformer 14 Discharge electrode 25 Ground electrode

Claims (1)

[Scope of utility model registration request] 1. A step-up transformer whose primary side is connected to an AC power source, a discharge electrode coupled to one end on the secondary side of the step-up transformer, and a step-up transformer arranged so as to face the discharge electrode. A static eliminator having a ground electrode connected to the other end of the secondary side of the ground electrode, the static charge removing a charge of a charged object oppositely contacting both electrodes, a surface of the ground electrode facing the charged object. A static eliminator, characterized in that a recess is provided in the recess so that the tip of the discharge electrode projects from the recess and does not project from the peripheral portion of the recess.