KR100924112B1 - Micro Plasma Device with Hollow Cathode Structure - Google Patents

Abstract

The present invention relates to a device for generating plasma efficiently by using a structure of a hollow cathode device. Plasma generating device according to the present invention, a hollow formed in at least one of the front substrate and the back substrate, and formed in the hollow between the first metal electrode included in the front substrate and the second metal electrode included in the back substrate. The electric field may be used to efficiently generate plasma.

Hollow Cathode Devices, Plasma, Flat Panel Lamps, PDP

Description

A device for generating plasma in a discharge cell having a hollow electrode {Micro Plasma Device with Hollow Cathode Structure}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma generating device, and more particularly, to a device for generating plasma efficiently by using a structure of a hollow cathode device.

Recently, as the technology related to flat panel displays such as liquid crystal displays (hereinafter referred to as LCDs) and plasma display panels (hereinafter referred to as PDPs) has been developed, the size of panels has become larger and larger. . In particular, LCDs require a separate light source (back light unit; hereinafter referred to as BLU) in terms of driving method, and AC flat fluorescence lamp (hereinafter referred to as AC FFL) is a representative element of BLU. It is used.

The AC FFL emits light using visible light emitted by a vacuum ultra violet (VUV; wavelength 147 nm, 173 nm) generated by a glow discharge.

1 is a perspective view of an AC FFL according to the prior art, and FIG. 2 is a cross-sectional view of the cross section of FIG. 1. 1 and 2, the discharge cell constituting the AC FFL is largely composed of an upper front substrate and a lower rear substrate. On the front substrate, a sustain electrode for lowering resistance is formed on a transparent electrode having excellent light transmittance, and a dielectric film for protecting the electrode is formed on these electrodes, and an MgO protective film for promoting secondary electron emission is formed thereon. have. The back substrate is coated with a dielectric film having good reflectance of light and a phosphor for emitting light due to discharge, and a spacer is disposed thereon to secure a discharge space thereon. When these two substrates are in close contact with each other, a constant discharge space is secured by a spacer, and a discharge gas for glow discharge is injected into the discharge space of each discharge cell.

However, such a conventional AC FFL discharge cell structure needs to be improved more efficiently. Therefore, a discharge cell structure is required that can be applied to a discharge cell of an AC PDP operating on a principle similar to the discharge cell used in an AC FFL or an AC FFL of an LCD BLU to increase the generation efficiency of VUV, thereby obtaining more improved efficiency. have.

Accordingly, the present invention is to solve the above-described problems, the object of the present invention is to propose a structure of a hollow cathode device (hollow cathode device) for generating a plasma by an alternating current signal, the experiment carried out through the actual manufactured panel The present invention provides a plasma generating device that operates more efficiently by suggesting optimum conditions for obtaining maximum efficiency.

First, to summarize the features of the present invention, the plasma generating device according to one aspect of the present invention for achieving the above object of the present invention, forming a hollow on at least one of the front substrate and the rear substrate, the front substrate Plasma is generated by using an electric field formed in the hollow between the first metal electrode included in and the second metal electrode included in the rear substrate.

The generation of the plasma may be controlled according to at least one of the diameter, the depth of the hollow, and the pressure of the discharge gas injected into the discharge cell in which the hollow is formed.

In addition, the hollow may be formed by etching a dielectric film formed on the metal electrode or by etching one of the first metal electrode and the second metal electrode itself.

In addition, the hollow may have a wide cone having one end portion.

The first metal electrode may include at least one sustain electrode and an auxiliary electrode formed on the transparent electrode included in the front substrate, and the dielectric layer formed on the sustain electrode and the auxiliary electrode may correspond to the sustain electrode and the auxiliary electrode. It can be formed by etching for each position.

The first metal electrode includes a sustain electrode and an auxiliary electrode formed on the transparent electrode included in the front substrate, and the dielectric layer formed on the sustain electrode and the auxiliary electrode corresponds only to the sustain electrode among the sustain electrode and the auxiliary electrode. It can be formed by etching for each position.

The hollow may be formed by forming the second metal electrode on the dielectric film (oxide film) formed on the rear substrate, and then etching the second metal electrode from the second metal electrode to the dielectric film (oxide film).

The hollow may sequentially form a dielectric film (oxide film) and the second metal electrode on the patterned metal electrode and the patterned metal electrode on the rear substrate, and then the second metal electrode at a position corresponding to the patterned metal electrode. It can also be formed by etching from the dielectric film (oxide film).

The plasma generating device as described above may be used as a discharge cell of an FFL or AC PDP for an LCD.

According to the plasma generating device according to the present invention, it is possible to increase the light emission efficiency of the discharge cell by using the hollow cathode effect, and thus can be used in the discharge cell of the FFL or AC PDP for LCD can reduce the power consumption.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings and the contents described in the accompanying drawings, but the present invention is not limited or limited to the embodiments. Like reference numerals in the drawings denote like elements.

3 is a structure of a plasma generating device 300 having a hollow cathode according to an embodiment of the present invention.

Referring to FIG. 3, a plasma generating device 300 having a hollow cathode according to an embodiment of the present invention includes a transparent electrode 311, a metal electrode 312, and a dielectric film 313 formed on glass. A spacer 331 including a front substrate and a rear substrate including an aluminum electrode 321 formed on the glass, a dielectric film 322, and a hollow 323, and a discharge space between the front substrate and the rear substrate. It includes. Here, the plasma generating element 300 represents one discharge cell, and the discharge cells may be configured in an array form to be used in a flat lamp such as an AC FFL of an LCD BLU.

As shown in FIG. 3, the transparent electrode 311 is a transparent metal such as indium tin oxide (ITO), and is patterned between the spacers 331 on both sides of the discharge cell, and a high conductive material such as aluminum is used to lower the resistance of the transparent electrode 311. After the metal electrode 312 is applied, the pattern is narrower than the width of the transparent electrode 311 as shown in FIG. 3. A dielectric film 313 is formed on the metal electrode 312 to protect the transparent electrode 311 and the metal electrode 312.

In the back substrate, the aluminum electrode 321 is formed thick, and then the aluminum electrode 321 is coated with the dielectric film 322, and then a portion of the aluminum electrode 321 passes through the dielectric film 322 by a certain etching method. To be etched to form a hollow 323 as shown in FIG. Finally, the front substrate and the rear substrate are aligned to face each other and sealed while ensuring a discharge space for each discharge cell using the spacer 331, and then Xe, in the internal discharge space between the spacers 331 on both sides of the discharge cell. A predetermined discharge gas such as He is injected.

In FIG. 3, the transparent electrode 311 and the metal electrode 312 may be used as the anode, and the aluminum electrode 321 having the hollow 323 may be used as the cathode when the power is connected. In this case, an electric force line having a cylindrical equipotential surface having a shaft may be formed in the hollow 323 of the aluminum electrode 321. The electrons emitted from the cathode 321 are attracted to the anodes 311 and 312 while being rotated under the influence of the electric field, and are able to excite many Xe atoms by the plasma generated in this process. Can be divergent. Based on these effects, the efficiency of light emission can be improved.

4 is a graph of voltage vs. IR efficiency (infrared efficiency) as a result of experimenting with a plasma generating device according to an embodiment of the present invention.

As shown in Figure 4, as can be seen in the case of increasing the efficiency of the infrared (Infra Red; wavelength 828nm, 823nm; used as an indicator to estimate the amount of VUV generation) according to the role of the electrode 321 having a hollow 323, Due to the principle of alternating current driving, the anodes 311 and 312 and the cathode 321 have characteristics in which their polarities are alternated. Accordingly, the efficiency increase effect due to the hollow electrode 321 is alternately shown. As shown in FIG. 4, when the hollow electrode 321 serves as a cathode, the efficiency is higher than when the anode serves as an anode. . Because of the influence of the hollow cathode 321, when the above structure is applied to the discharge cell of the AC FFL of the LCD BLU can exhibit a high power efficiency.

FIG. 5 is a graph of hollow electrode depth versus Luminous Efficacy (lamp efficiency) as a result of experimenting with the plasma generating device 300 according to an embodiment of the present invention.

As shown in FIG. 5, when 300 tor Ne + 4% Xe Gas is injected into the plasma generating device 300 according to an embodiment of the present invention and applied to an AC FFL, the efficiency increases under a specific condition. This tendency is changed by two factors, the diameter and the depth of the hollow 323. First, in the case of the diameter, the efficiency rapidly increases from the pd product (Hole diameter * Gas pressure) below 1 torr * cm. This can be seen from the graph corresponding to Diameter 30μm in Figure 5 is 300torr * 30μm = 0.9torr * cm. In the case of the next depth, the result of the diameter of 100 μm shows the maximum efficiency at the depth * Gas pressure value around 2.4 torr * cm. By utilizing these conditions, it will be possible to manufacture AC FFLs that can achieve maximum efficiency. This can be seen from 300torr * 80μm = 2.4torr * cm at Depth 80μm showing maximum efficiency in the graph corresponding to Diameter 30μm in FIG. 5.

6 is a structure of a plasma generating device 600 according to another embodiment of the present invention.

Referring to FIG. 6, a plasma generating device 600 having a hollow cathode according to another embodiment of the present invention includes a transparent electrode 611, a metal electrode 612, a dielectric film 613, and a phosphor film formed on glass. A front substrate comprising a 614, and a back substrate comprising a metal electrode 621, a dielectric film 622, a hollow 624, and an MgO film 623 formed on glass, between the front substrate and the back substrate. Spacer 631 for securing the discharge space is included. As shown in FIG. 3, the plasma generating element 600 represents one discharge cell, and the discharge cells may be configured in an array form to be used in a flat lamp such as an AC FFL of an LCD BLU.

FIG. 6 is a slight modification of the structure of FIG. 3, wherein the structure of the front substrate is similar to that of FIG. 3 except for the phosphor film 614 formed on the dielectric film 613. An electrode 621 is formed. After the dielectric film 622 is thickly coated on the metal electrode 621, the dielectric film 622 is etched to just above the metal electrode 621 to form a hollow 623. Thereafter, an MgO film 624 is deposited on the hollow dielectric film 622 to achieve secondary electron emission. The transparent electrode 611 and the metal electrode 612 may be patterned between the spacers 331 on both sides as shown in FIG. 3, and the front and rear substrates manufactured as described above are aligned to face each other as shown in FIG. 631) to seal while securing a discharge space. Since the transparent electrode 611 and the metal electrode 612 are both surrounded by the dielectric film 613, the lifespan can be increased.

7 is a structure of a plasma generating device 700 according to another embodiment of the present invention. Referring to FIG. 7, a plasma generating device 700 having a hollow cathode according to another exemplary embodiment of the present invention may include a transparent electrode 711, a sustain electrode 712, an auxiliary electrode 713, and a dielectric film formed on glass. 714, a hollow substrate 715, and a front substrate including an MgO film 716, and an address electrode 721, a dielectric film 722, a partition 723, and a phosphor film 724 formed on glass. It includes a back substrate. Here, the plasma generating element 700 represents one discharge cell, and the discharge cells are configured in an array form to be used in a flat panel display such as an AC PDP. As can be seen in the cross-sectional view of FIG. 7, the sustain electrode 712 and the auxiliary electrode 713 of the front substrate and the address electrode 721 of the rear substrate are formed in a pattern in which the longitudinal directions (length directions) are perpendicular to each other.

In FIG. 7, the storage electrode 712 and the auxiliary electrode 713 formed in parallel on the same transparent electrode 711 are patterned, and after the dielectric film 714 is applied thereon, the dielectric film 814 is held on the storage electrode. The hollow 715 is formed at the corresponding position to be etched to just above the 712 and the auxiliary electrode 713 to be slightly larger or smaller than the width of the sustain electrode 712 and the auxiliary electrode 713. The hollow 715 may be formed in various shapes, such as a square shape and a circular shape, and may be formed in a wide conical shape (a wide conical shape and a narrow conical shape at one end) as shown by a dotted line in FIG. 7. The MgO film 716 is formed on the dielectric film 714 on which the hollow 715 is formed ( as shown in FIG. 7, in the hollow 715, that is, the sidewalls and the bottom of the hollow 715). MgO film 716 is also formed on the surface) . In the back substrate, a metal electrode (address electrode) 721 is formed on a glass substrate and then coated with a dielectric film 722. The discharge space is secured by the partition wall 723, and a phosphor film 724 is formed between the partition walls 723 on both sides of the discharge cell. Here, the phosphor film 724 is formed up to side surfaces of both partition walls 723. When such a discharge cell structure is used in a flat panel display such as an AC PDP, for example, as described with reference to FIG. 3, the address electrode 721 may be categorized according to the operating principle of a flat panel display such as an AC PDP. The sustain electrode 712 or the auxiliary electrode 713 on the front substrate and the address electrode 721 on the back substrate, in order to be used as an anode) and to use the sustain electrode 712 or the auxiliary electrode 713 as an anode (or cathode) as appropriate. When the plasma is generated by the power connection therebetween, the efficiency of light emission may be improved by using an electric field formed in the hollow 715.

8 is a modification of the plasma generating element 700 of FIG.

Referring to FIG. 8, a plasma generating device 800 having a hollow cathode according to another exemplary embodiment may include a transparent electrode 811 formed on glass and a storage electrode 812 formed in parallel on the same transparent electrode 811. ) And a front substrate including an auxiliary electrode 813, a dielectric film 814, a hollow 815, and an MgO film 816, an address electrode 821, a dielectric film 822, and a partition wall 823 formed on glass. And a back substrate including the phosphor film 824. Here, the plasma generating element 800 represents one discharge cell, and the discharge cells may be arranged to be used in a flat panel display such as an AC PDP. As can be seen in the cross-sectional view of FIG. 8, the sustain electrode 812 and the auxiliary electrode 813 of the front substrate and the address electrode 821 of the rear substrate are patterned in a direction in which the long direction (length direction) is perpendicular to each other.
When such a discharge cell structure is used in a flat panel display such as an AC PDP, for example, as described with reference to FIG. 3, the address electrode 821 may be a cathode (or a cathode) according to an operation principle of a flat panel display such as an AC PDP. The sustain electrode 812 or the auxiliary electrode 813 of the front substrate and the address electrode 821 of the back substrate, in order to use the anode and the sustain electrode 812 or the auxiliary electrode 813 as appropriate anodes (or cathodes). When the plasma generated by the power connection between the use of the electric field formed in the hollow 815 can improve the efficiency of light emission.

When the discharge cell as shown in FIG. 8 is used in a flat panel display such as an AC PDP, the auxiliary electrode 813 does not participate in a strong discharge, and therefore, a large efficiency increase due to the hollow of the auxiliary electrode 813 is expected. Difficult to do Therefore, as shown in FIG. 8, although the hollow is formed only at the corresponding positions on both of the sustain electrodes 812 except for the auxiliary electrode 813, the efficiency increase amount is large compared to the case of FIG. 7. It is not expected to be visible.

9 is a structure of a plasma generating device 900 according to another embodiment of the present invention.

9, a plasma generating device 900 having a hollow cathode according to another exemplary embodiment of the present invention may include a transparent electrode 911, a sustain electrode 912, a dielectric film 913, and a partition wall formed on glass. 914, and a front substrate including a phosphor film 915, a dielectric film 921 formed on glass, an Al ₂ O ₃ oxide film 922, an Al metal film 923, a hollow 924, and an MgO film ( And a back substrate comprising 925). Here, the plasma generating element 900 represents one discharge cell, and the discharge cells may be configured in an array form to be used in a flat lamp such as an AC FFL of an LCD BLU.

In FIG. 9, the hollow 924 passes through the Al metal film 923 by a constant etching method after Al ₂ O ₃ oxide film 922 and Al metal film 923 are coated on the dielectric film 921 on the back substrate. It is formed by etching to the Al ₂ O ₃ oxide film 922, which is a kind of dielectric film. Here, the phosphor film 915 is formed from the front substrate to side surfaces of both partition walls 914, and other films are formed as shown in FIG. 9. When such a discharge cell structure is used for a flat lamp such as an AC FFL of an LCD BLU, the highest hollow cathode effect than other structures can be expected.

10 is a modification of the plasma generating device 900 of FIG. 9.

Referring to FIG. 10, a plasma generating device 1000 having a hollow cathode according to another exemplary embodiment may include a transparent electrode 1011, a sustain electrode 1012, a dielectric film 1013, and a partition wall formed on glass. 1014, and a front substrate including a phosphor film 1015, an address electrode 1021, a dielectric film 1022, an Al ₂ O ₃ oxide film 1023, an Al metal film 1024, and a hollow 1025 formed on glass. And a MgO film 1026 (the MgO film 1026 is formed in the hollow 1025, that is, the sidewalls and bottom surfaces of the hollow 1025) . As can be seen in the cross-sectional view of FIG. 10, the sustain electrode 1012 of the front substrate and the address electrode 1021 of the rear substrate are patterned in a direction in which the longitudinal direction (length direction) is perpendicular to each other.

As shown in the cross-sectional view of FIG. 10, a discharge cell structure in which an address electrode 1021 of a patterned metal is formed at a corresponding position under the hollow 1025 before the dielectric film 1022 is formed is formed in an array form, such as an AC PDP. It can be used in a flat panel display device. For example, as described with reference to FIG. 3, light is generated using an electric field formed in the hollow 1025 for plasma generation by a power connection between the sustain electrode 1012 of the front substrate and the address electrode 1021 of the rear substrate. It can improve the efficiency of the release.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

1 is a structure of an AC type flat lamp according to the prior art.

FIG. 2 is a cross-sectional view of the AC flat panel lamp of FIG. 1.

3 is a structure of a plasma generating device having a hollow cathode according to an embodiment of the present invention.

4 is a graph of voltage vs. IR efficiency (infrared efficiency) as a result of experimenting with a plasma generating device according to an embodiment of the present invention.

5 is a graph of hollow electrode depth vs. Luminous Efficacy (lamp efficiency) of the plasma generation device according to an embodiment of the present invention.

6 is a structure of a plasma generating device according to another embodiment of the present invention.

7 is a structure of a plasma generating device according to another embodiment of the present invention.

FIG. 8 is a modification of the plasma generating device of FIG. 7.

9 is a structure of a plasma generating device according to another embodiment of the present invention.

FIG. 10 is a modification of the plasma generating device of FIG. 9.

Claims (8)

An array structure of discharge cells comprising a front substrate having a first metal electrode and a rear substrate having a second metal electrode formed perpendicular to the first metal electrode, In each discharge cell, the first metal electrode includes at least one sustain electrode and an auxiliary electrode formed in parallel on the same transparent electrode formed on the front substrate, and includes a dielectric film formed on the sustain electrode and the auxiliary electrode. A hollow formed by etching to a predetermined depth of the dielectric film at each position corresponding to the sustain electrode and the auxiliary electrode, And an electric field formed in the hollow for generating plasma by the power supply connection between the sustain electrode or the auxiliary electrode and the second metal electrode. An array structure of discharge cells comprising a front substrate having a first metal electrode and a rear substrate having a second metal electrode formed perpendicular to the first metal electrode, In each discharge cell, the first metal electrode includes a sustain electrode and an auxiliary electrode formed in parallel on the same transparent electrode formed on the front substrate, and the dielectric electrode formed on the sustain electrode and the auxiliary electrode is connected to the sustain electrode. A hollow formed by etching to a predetermined depth of the dielectric film at positions corresponding to only the storage electrodes of the auxiliary electrodes, And an electric field formed in the hollow for generating plasma by the power supply connection between the sustain electrode or the auxiliary electrode and the second metal electrode. An array structure of discharge cells comprising a front substrate having a first metal electrode and a rear substrate having a second metal electrode formed perpendicular to the first metal electrode, In each discharge cell, a dielectric film, an oxide film, and a metal film are sequentially formed on the second metal electrode and the second metal electrode patterned on the rear substrate, and then the metal film is removed from the metal film at a position corresponding to the second metal electrode. It includes a hollow formed by etching to the oxide film, Plasma generating element, characterized in that for using the electric field formed in the hollow for generating a plasma by the power connection between the first metal electrode and the second metal electrode. The method according to any one of claims 1 to 3, And the hollow is formed in a predetermined diameter with respect to the depth of the hollow in relation to the generation efficiency of the plasma at a constant pressure of the discharge gas injected into the discharge cell. The method according to claim 1 or 2, An oxide film is formed on the front substrate on which the hollow is formed (the oxide film is formed on the sidewalls and bottom of the hollow), and a dielectric film and a fluorescent film are sequentially formed on the second metal electrode of the back substrate. . The method of claim 3, And an oxide film is formed on the rear substrate on which the hollow is formed (the oxide film is formed on the sidewalls and the bottom of the hollow), and a dielectric film and a phosphor film are sequentially formed on the first metal electrode of the front substrate. The method according to any one of claims 1 to 3, The hollow is a plasma generating element, characterized in that the inlet is wide and the bottom is narrow conical. The plasma generating element according to any one of claims 1 to 3, wherein the plasma generating element is used as a discharge cell of an AC PDP.

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