KR20030059692A - Atmospheric pressure plasma jet and surface-treating apparatus for CRT therewith - Google Patents

Abstract

PURPOSE: An atmospheric pressure plasma jet and a cathode ray tube surface processor are provided to perform a stable glow discharge at atmospheric pressure and efficiently process a surface of a cathode ray tube. CONSTITUTION: A lower portion of a housing(110) is open. A gas injection pipe(122) pierces the housing(110). Two electrode plates(130) are vertically formed at an inside of the housing(110). A gas mixing chamber(140) is connected to of an upper slit(134) of the two electrode plates(130) at an upper portion of the housing(110). The electrode plates(130) includes the upper slit(134) and a lower slit(136). Each of the electrode plates(130) is manufactured by an aluminum or an aluminum alloy. A plurality of holes(122) are formed at an upper portion of the gas injection pipe(122). An alumina oxide dielectric film(132) is formed at an inside of the electrode plates(130) by oxidizing a surface of the electrode plates(130).

Description

Atmospheric pressure plasma jet and surface-treating apparatus for CRT therewith}

The present invention relates to an atmospheric plasma jet and a cathode ray tube surface treatment apparatus having the same.

In general, it is very difficult to make a glow discharge at atmospheric pressure using a plasma process. This is because the gas density is high at atmospheric pressure, so the discharge current density is large, and thus the transition to arc is easy. In the industrial field, such an arc plasma is used for welding or cutting.

Atmospheric pressure plasma can be largely divided into a dielectric barrier discharge (DBD) method and a jet method. In the case of the DBD, as shown in FIG. 1, a dielectric film 20 is inserted into the metal electrode 10 to lower the current density to generate plasma between the electrodes 10. To do this, make an interval of about 4 to 8 mm between electrodes 10 and apply a voltage of several kV.

However, this method is limited to flat products with thin shapes, and cannot be used for surface treatment of large volume CRTs.

In the jet method, as shown in FIG. 2, a gas is blown between the electrodes 30 to generate a plasma, and the radicals generated after ejecting the generated radicals onto the object 40 are removed. There is no restriction on the shape.

In this system, however, there is a problem in that the distribution of the gas introduced into the plasma reaction chamber is uneven and the arc discharge easily occurs.

On the other hand, the multilayer film coating layer is formed on the surface of the cathode ray tube, the first layer film is a coating for electromagnetic shielding. However, the cost of the coating liquid of the first layer film is high and the amount of waste is largely unfriendly to the environment. The process for improving this is not established, and in a special case, there is a method of injecting the entire cathode ray tube into the vacuum chamber using a conventional vacuum plasma method.

However, this method has to be equipped with several chambers such as loading chamber, unloading chamber and buffer chamber for continuous surface treatment of cathode ray tube, and the processing cost is also expensive to apply to cathode ray tube surface treatment process.

An object of the present invention was created to improve the above problems, and an object of the present invention is to provide a plasma jet that has a stable glow discharge at atmospheric pressure.

Another object of the present invention is to provide a cathode ray tube surface treatment apparatus having a plasma jet capable of efficiently treating the surface of the cathode ray tube using the plasma jet.

1 is a schematic view showing an apparatus for generating a plasma by a dielectric barrier discharge (DBD) method;

2 schematically shows an apparatus for generating a plasma in a jet (JET) manner;

3 is a schematic perspective view of an atmospheric plasma JET according to a first embodiment of the present invention;

4 is a cross-sectional view taken along the line IV-IV of FIG.

5 is a perspective view of a cathode ray tube surface treatment apparatus having an atmospheric plasma jet according to a second embodiment of the present invention;

6 is a schematic cross-sectional view showing an example of using the cathode ray tube processing apparatus of FIG.

7A and 7B are photographs of the cathode ray tube using the cathode ray tube surface treatment apparatus according to the second embodiment of the present invention, and the surface of the cathode ray tube not subjected to the surface treatment after coating treatment.

<Code Description of Main Parts of Drawing>

100: atmospheric plasma jet 110: housing

120: gas injection tube 130: electrode plate

132: dielectric film 134: upper slits

136: lower slits 140: gas mixing chamber

160: vertical actuator 170: horizontal actuator

180: displacement sensor 200: cathode ray tube surface treatment apparatus

In order to achieve the above object, the atmospheric pressure plasma jet of the present invention, the lower portion of the opening, forming a housing; Two electrode plates which are vertically spaced apart from each other at a lower part of the housing by a predetermined distance, the upper part of which forms a mixed gas inlet, and the lower part of which forms an outlet of a plasma discharged gas; A dielectric film formed on an inner surface of each electrode plate; A gas mixing chamber formed on the electrode plates in the housing and connected to the mixing gas inlet to uniformly supply the mixing gas between the electrode plates; And a gas injection pipe for supplying gas to the gas mixing chamber.

Preferably, the gas injection pipe has a plurality of holes formed therein so as to penetrate the gas mixing chamber and blow off the gas above the mixing chamber.

In order to achieve the above another object, the cathode ray tube surface treatment apparatus having an atmospheric plasma jet of the present invention, the atmospheric pressure plasma jet; A plate supporting the plasma jet; A vertical actuator connected to the plate to drive both ends of the atmospheric plasma jet in a vertical direction; And a horizontal actuator connected to the vertical actuator to drive the atmospheric plasma jet in the x-axis direction.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment according to the atmospheric plasma jet of the present invention and a cathode ray tube surface treatment apparatus having the same. In this process, the thicknesses of layers or regions illustrated in the drawings are exaggerated for clarity.

3 is a schematic perspective view of the atmospheric plasma jet 100 according to the first embodiment of the present invention, Figure 4 is a cross-sectional view of the cut along the line IV-IV of FIG.

Referring to the drawings, the housing 110, which is shaped as a plastic material and whose bottom is opened, is illustrated. Both sides of the housing 110 are penetrated by the gas injection pipe 122. In the housing 110, two electrode plates 130 are vertically spaced apart from each other by a predetermined distance from the bottom thereof. The electrode plate 130 is sealed at its side by a housing, and the upper slits 134 are connected to the gas mixing chamber 140 formed on the upper part of the housing 110, and the lower slits 136. The plasma discharged acts as a gas outlet.

A plurality of holes 122 are formed at an upper portion of the gas injection pipe 120 in the housing 110, and the gas injected from both ends of the gas injection pipe 120 through the holes 122 is a gas mixing chamber ( After being uniformly mixed in the gas mixing chamber 140 while being ejected upward of the 140, it flows between the electrode plates 130 through the upper slits 134.

Each electrode plate 130 is made of aluminum or an aluminum alloy in a shape of a rectangular plate having a long length in the transverse direction, and a thin alumina dielectric layer 132 is formed therein. The alumina oxide dielectric layer 132 is preferably formed by oxidizing the surface of aluminum, which is the electrode plate 130. One of the electrode plates 130 is connected to a pulsed direct current, a radio frequency (RF), a direct current or an alternating current power source, and the other electrode is connected to the ground to generate a glow discharge between both electrodes.

The gap between the dielectric layers 132 is preferably maintained at 10 mm or less.

The operation of the atmospheric plasma jet 100 of the above structure will be described in detail with reference to the drawings. He, Ar, N2, air or the like is used as the discharge gas to be injected between the electrode plates 30. In general, when the He gas is added first, the discharge voltage is lowered. Subsequently, it converts into Ar or air, etc., and injects.

When the gas is injected at both ends of the gas injection pipe 120, the injected gas is ejected into a plurality of holes 122 formed in the upper portion of the injection pipe 120 and directed upward. The ejected gas is uniformly mixed in the gas mixing chamber 140 and then introduced between the electrode plates 130 through the upper slits 134. The introduced gas becomes a laminar flow by the two electrode plates 130 so that the gas flow is uniformly distributed over the entire area.

At this time, when any one of RF, AC, DC, and Pulsed DC is applied to the other electrode plate while one electrode plate 130 is grounded, glow discharge occurs between the electrode plates 130. Oxygen radicals occur in the glow discharge depending on the inlet gas. Reaction radicals with high surface hydrophilicity are generally ozone and oxygen ions. These reaction radicals are evenly sprayed through the lower slits 136.

5 is a perspective view of a cathode ray tube surface treatment apparatus 200 having an atmospheric pressure plasma jet according to a second embodiment of the present invention. The same reference numerals are used for the same components as those of the first embodiment, and detailed description thereof will be omitted.

Referring to the drawings, the plasma jet 100 in the first embodiment is installed so that its lower slits (136 in Fig. 4) are directed downward. Both sides of the rear surface of the plasma jet 100 are connected to two vertical actuators 160 through connecting plates 150, respectively. The vertical actuator 160 is vertically moved along the support shaft 162 penetrating therein. The upper end of the connection plate 150 is provided with a bearing 154 in which the hinge 152 fixed to the vertical actuators 160 are rotated therein, and the lower end of the hinge plate 152 fixed to the plasma jet 100. A bearing 158 is provided in which 156 is rotated.

The vertical actuators 160 are driven independently on the z-axis, and when the vertical actuator 160 on one side moves, the hinges 156 rotate in the bearings 158 and the plasma jet 100 is inclined. Can be.

Above the plasma jet 100, a horizontal actuator 170 having an upper portion thereof fixed to a horizontal plate 164 connecting the vertical actuators 160 is provided. The horizontal actuator 170 is moved in the x-axis direction along a support shaft 172 penetrating therein.

The lower end of the support shaft 162 is connected to the connecting portion 166 on the rail 168 and moved in the x direction according to the movement of the horizontal actuator 172.

On both sides of the plasma jet 100, displacement sensors 180 are provided for measuring the position of the surface of the cathode ray tube (see 192 in FIG. 6) located below the plasma jet 100. The displacement sensor 180 is provided so that the lower slits 136, which are gas outlets of the plasma jet 100, maintain a constant distance from the surface of the cathode ray 192 tube.

6 is a schematic cross-sectional view showing an example of using the cathode ray tube processing apparatus 200 of FIG.

Referring to the drawings, the cathode ray tube 192 is mounted on the support 194 on the conveyor belt 190 to move in the conveyor logistics direction. The cathode ray tube processing apparatus 200 is located on the support 174 across the conveyor belt 192. The cathode ray tube 192 on the conveyor belt 190 is stopped below the cathode ray tube surface treatment apparatus 200. The displacement sensor 180 measures a distance from the surface of the cathode ray tube 192 and inputs the measurement result to a controller (not shown).

The controller drives the vertical actuators 160 to eliminate the deviation between the sides of the plasma jet 100 and the surface of the cathode ray tube 192 from the position information of the displacement sensor 180.

The singer displacement sensor 180 and the controller operate in a stationary and moving state.

The cathode ray tube processing apparatus 200 maintains a constant distance between the outlet slits 136 of the plasma jet 100 and the surface of the cathode ray tube 192 and then moves to the X axis to treat the surface of the cathode ray tube. When the X-axis moves, the distance between the lower slits 136 of the plasma jet 100 and the surface of the cathode ray tube 192 may change. The displacement (sensor 180) detects the distance to the surface of the cathode ray tube 192 when the plasma jet 100 moves in the X-axis, and transmits the detected information to the controller. The vertical actuators 160 are driven to maintain a constant distance between the surface of the plasma jet 100 and the cathode ray tube 192.

When the surface of the cathode ray tube 192 is treated, the distance between the lower slits 1360 of the plasma jet 100 and the surface of the cathode ray tube 192 should be kept constant as follows: Reactive radicals generated in the plasma jet 100. They have a certain life time, so multiplying the rate and the survival time when ejected into the lower slits 136 gives the distance the reactive radicals will affect, so that the surface of the cathode ray tube is hydrophilic. The reactive radicals must be located within the range of influence and the plasma electrode must pass through the cathode ray tube while maintaining a constant distance from the cathode ray tube surface to form uniform surface energy on the entire surface of the cathode ray tube after surface treatment.

Next, while discharging the gas discharged from the plasma jet 100 to the surface of the cathode ray tube 192, the horizontal actuator 170 moves on the x-axis to evenly spray plasma onto the surface of the cathode ray tube.

Reactive radicals such as ozone and oxygen ions of the injected gas react with organic substances on the surface of the cathode ray tube 192 to break the bond between carbon (C) and hydrogen (H), form CO2 and H2O, and some react with carbon. To form a hydrophilic group (CO =, COOH-). This hydrophilic group dramatically improves the wettability of the CRT surface. In addition, uniform energy is formed on the surface of the cathode ray tube so that it is isotropic in spin coating.

7A and 7B are photographs comparing the coating properties of a cathode ray tube using a cathode ray tube surface treatment apparatus according to a preferred embodiment of the present invention, and a cathode ray tube not subjected to surface treatment, respectively.

In the experiment, the cathode ray tube was placed on a rotating plate rotated at 120 rpm, dropped 2 cc of coating liquid, rotated for 14 seconds, and the spreading amount of the coating liquid was recorded in a stopped state. The surface coating layer of the cathode ray tube consists of several layers of coating, and the type of coating liquid used for the first layer film is determined according to the electromagnetic shielding standard.

Referring to the drawings, the cathode ray tube subjected to the plasma treatment is evenly spread (see FIG. 7A), but it can be seen that the spread of the coating on the cathode ray tube not surface-treated with plasma is reduced (see FIG. 7B).

In addition, it was possible to reduce the coating liquid by about 30% when coating the cathode ray tube surface-treated with the plasma jet of the present invention.

As described above, the atmospheric pressure plasma jet according to the present invention stably causes glow discharge, and uniform radicals are emitted from the plasma jet outlet. In addition, the cathode ray tube surface treatment apparatus having an atmospheric plasma jet according to the present invention makes it possible to evenly and economically follow the coating process by pretreating the surface of the cathode ray tube.

Although the present invention has been described with reference to the embodiments with reference to the drawings, this is merely exemplary, it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined only by the appended claims.

Claims (9)

A lower portion of which is opened and forms a housing; Two electrode plates which are vertically spaced apart from each other at a lower part of the housing by a predetermined distance, the upper part of which forms a mixed gas inlet, and the lower part of which forms an outlet of a plasma discharged gas; A dielectric film formed on an inner surface of each electrode plate; A gas mixing chamber formed on the electrode plates in the housing and connected to the mixing gas inlet to uniformly supply the mixing gas between the electrode plates; And And a gas injection pipe for supplying gas to the gas mixing chamber. The method of claim 1, The gas injection pipe, And a plurality of holes formed therein so as to penetrate the gas mixing chamber and blow out the gas above the mixing chamber. The method of claim 1, Atmospheric pressure plasma jet, characterized in that the plate electrode is made of aluminum or aluminum alloy. The method of claim 1, Wherein said dielectric film is alumina oxide. The atmospheric plasma jet according to claim 1; Vertical actuators connected to the plasma jets to drive both ends of the atmospheric pressure plasma jet in a vertical direction; And And a horizontal actuator connected to a plate connecting the vertical actuators to drive the atmospheric plasma jet in the x-axis direction. The method of claim 5, And the atmospheric pressure plasma jet and the vertical actuator are hingedly connected. The method of claim 5, The gas injection pipe, Cathode ray tube surface treatment apparatus having an atmospheric pressure plasma jet, characterized in that a plurality of holes formed in the upper portion to pass through the gas mixing chamber and to eject the gas above the mixing chamber. The method of claim 6, A displacement sensor for measuring a distance from a surface of a cathode ray tube in which the plasma jet is located below; And And a controller for measuring the z-axis distance from the displacement sensor and driving the vertical actuators from the result to maintain a constant distance from the surface of the cathode ray tube. Surface treatment equipment. The method of claim 8, The displacement sensor observes the surface of the cathode ray tube located below the gauge to measure whether the surface of the cathode ray tube and the outlet of the plasma jet is horizontal, And the controller drives the vertical actuators according to the horizontal measurement result.