阅读说明：本技术 一种用于镀膜的冷阴极电子枪装置 (Cold cathode electron gun device for coating film ) 是由 许海鹰 桑兴华 于 2019-11-04 设计创作，主要内容包括：一种用于镀膜的冷阴极电子枪装置,包括室外枪体组件和室内偏转线圈组件,室外枪体组件的电子枪壳体的外部一端安装固定套环、另一端通过法兰固定在真空室壁上,并与真空室内的室内偏转线圈组件连接；电子枪壳体的内部一端设有阴极组件、另一端设有阳极组件,阴极组件通过绝缘子与固定套环连接,阴极组件包括导电套环,水冷散热器和金属阴极,金属阴极的一端内凹形成反球面、另一端嵌入陶瓷套筒,陶瓷套筒中设有六硼化铼阴极,水冷散热器的内部设置环形水冷通道。本发明可使阴极组件寿命大幅提高,从而减少更换频率,提高镀膜质量。(A cold cathode electron gun device for coating comprises an outdoor gun body assembly and an indoor deflection coil assembly, wherein one end of the outer part of an electron gun shell of the outdoor gun body assembly is provided with a fixed lantern ring, and the other end of the outer part of the electron gun shell of the outdoor gun body assembly is fixed on the wall of a vacuum chamber through a flange and is connected with the indoor deflection coil assembly in the vacuum chamber; the inside one end of electron gun casing is equipped with negative pole subassembly, the other end is equipped with the anode assembly, and the negative pole subassembly passes through the insulator and is connected with fixed lantern ring, and the negative pole subassembly includes the conductive sleeve ring, water-cooling radiator and metal cathode, and the one end indent of metal cathode forms spherical surface, other end embedding ceramic sleeve, is equipped with the rhenium hexaboride negative pole in the ceramic sleeve, and the inside of water-cooling radiator sets up annular water-cooling passageway. The invention can greatly prolong the service life of the cathode component, thereby reducing the replacement frequency and improving the coating quality.)

1. A cold cathode electron gun device for coating comprises an outdoor gun body assembly and an indoor deflection coil assembly, and is characterized in that one end of the outer part of an electron gun shell of the outdoor gun body assembly is provided with a fixed lantern ring, and the other end of the outer part of the electron gun shell of the outdoor gun body assembly is fixed on the wall of a vacuum chamber through a flange and is connected with the indoor deflection coil assembly in the vacuum chamber; one end of the interior of the electron gun shell is provided with a cathode component, the other end of the interior of the electron gun shell is provided with an anode component, the cathode component is connected with the fixed lantern ring through an insulator, wherein,

the cathode assembly comprises a conductive sleeve ring coaxially mounted with the insulator, and a water-cooled radiator and a metal cathode which are connected with the inner wall of the conductive sleeve ring, wherein the metal cathode is inwards concave towards one end of the anode assembly to form an inverse spherical surface, the other end of the metal cathode is inwards concave and is embedded into a ceramic sleeve, a rhenium hexaboride cathode is mounted in the ceramic sleeve, a sealed annular water-cooled channel is arranged inside the water-cooled radiator, and the annular water-cooled channel is connected with an external water-cooled system through a water inlet pipe and a water outlet pipe which are arranged on the water-cooled radiator;

the indoor deflection coil assembly is used for deflecting the electron beam output from the anode assembly so that the electron beam reaches the upper surface of the target on one side of the anode assembly.

2. The cold cathode electron gun device for coating according to claim 1, wherein the outer wall of one end of the water-cooled heat sink is in threaded connection with the inner wall of the insulator, the outer wall of the other end of the water-cooled heat sink is in threaded connection with the inner wall of the conductive collar, and the middle protruding part extends into the ceramic sleeve to abut against the rhenium hexaboride cathode;

the outer wall of the metal cathode is in threaded connection with the inner wall of the conductive lantern ring.

3. The cold cathode electron gun apparatus for coating according to claim 1, wherein a surface of the metal cathode contacting the water-cooled heat sink is coated with a heat conductive silicone grease.

4. The cold cathode electron gun apparatus for coating according to claim 1, wherein a high voltage input connection terminal is provided in the water-cooled heat sink for connecting the cathode assembly with a negative high voltage power supply;

the anode assembly is grounded so as to form an accelerating electric field with the cathode assembly.

5. The cold cathode electron gun device for coating according to claim 1, wherein the anode assembly comprises an anode body having one end thereof clamped to an end of the electron gun housing and the other end thereof extending into the interior of the electron gun housing, wherein,

an anode hole for passing an electron beam is arranged on the central axis of the anode main body;

an annular water channel is arranged in the anode main body and is connected with an external water cooling system through an anode water inlet pipe and an anode water outlet pipe which are arranged on the anode main body;

the outer wall of the anode main body is provided with an air duct, and the inner side of the anode main body is provided with an air outlet.

6. The cold cathode electron gun apparatus for coating according to claim 5, wherein a partition is provided inside the annular water passage, and the anode water inlet pipe and the anode water outlet pipe are respectively provided on both sides of the partition.

7. The cold cathode electron gun apparatus for coating according to claim 1, wherein said indoor deflection coil assembly comprises a focusing coil, a first deflection coil and a scanning coil arranged in this order next to said anode assembly, a second deflection coil installed at an angle of 45 ° to said scanning coil, and a permanent magnet deflection magnetic field arranged between said second deflection coil and said target.

8. The cold cathode electron gun apparatus for coating according to claim 7, wherein the second deflection coil is a symmetrical pole piece coil structure.

9. The cold cathode electron gun apparatus for coating according to claim 1, wherein said indoor deflection coil assembly comprises a focusing coil, a scanning coil and a second deflection coil arranged in this order in close proximity to said anode assembly, and a permanent magnet deflection magnetic field disposed between said second deflection coil and said target.

10. The cold cathode electron gun apparatus for coating according to claim 9, wherein the second deflection coil has a pair of planar spiral structures.

Technical Field

The invention relates to the technical field of optical coating, in particular to a cold cathode electron gun device for coating.

Background

In recent years, optical coating technology has been continuously developed, and the market growth trend of coating equipment is remarkable.

The vacuum coating method of optical coating generally includes resistance evaporation, electron beam evaporation, magnetron sputtering, ion beam direct deposition, etc., wherein: resistance evaporation is difficult to be used for evaporation of refractory metals such as tungsten, molybdenum, tantalum and the like, and chemical reaction is easy to occur due to the temperature difference between evaporation materials and a crucible, so that the quality of a coating film is reduced; the electron beam evaporation vacuum coating technology is a method which uses an electron beam as a heat source to heat a coating material in a crucible to gasify the coating material and deposit the coating material on a substrate with lower temperature to form a required film, and the application of an electron beam source greatly expands the selection range of the coating material of the vacuum coating technology; the magnetron sputtering technology has low utilization rate of the target material, generally only 40 percent, and the film layers of the prepared multilayer film are easy to be polluted; the ion beam sputtering generally bombards the target material with smaller area, the deposition efficiency is generally not high, and the sputtering device is more complicated and the operation cost is high; the ion beam direct deposition technology has a wide range of coating materials, but the commonly used RF ion source for preparing high-quality films has a complex structure and is difficult to operate and maintain.

At present, most of the applications are electron beam evaporation vacuum coating, and electron beam sources developed by domestic and foreign research institutions of electron beam evaporation vacuum coating technology are almost electron beam source technology based on hot cathodes. The hot cathode electron beam source usually adopts a tungsten filament as a cathode, and the heating of the cathode can bring about the volatilization of tungsten vapor, which can cause the quality reduction of a film layer; and the cathode has a limited service life, which is as long as 20-30 hours, and is difficult to be applied to high-quality film preparation.

Disclosure of Invention

The embodiment of the invention provides a cold cathode electron gun device for coating, which ensures the long-term stable work of a cathode assembly by arranging a water cooling channel in the cathode assembly, greatly prolongs the service life of the cathode assembly, reduces the replacement frequency of the cathode assembly and effectively improves the coating quality.

A cold cathode electron gun device for coating comprises an outdoor gun body assembly and an indoor deflection coil assembly, wherein a fixed lantern ring is installed at one end of the outer part of an electron gun shell of the outdoor gun body assembly, and the other end of the outer part of the electron gun shell of the outdoor gun body assembly is fixed on the wall of a vacuum chamber through a flange and is connected with the indoor deflection coil assembly in the vacuum chamber; a cathode component is arranged at one end of the interior of the electron gun shell, an anode component is arranged at the other end of the interior of the electron gun shell, the cathode component is connected with the fixed lantern ring through an insulator, wherein,

the cathode assembly comprises a conductive sleeve ring coaxially mounted with the insulator, and a water-cooled radiator and a metal cathode which are connected with the inner wall of the conductive sleeve ring, wherein the metal cathode is inwards concave towards one end of the anode assembly to form an inverse spherical surface, the other end of the metal cathode is inwards concave and is embedded into a ceramic sleeve, a rhenium hexaboride cathode is mounted in the ceramic sleeve, a sealed annular water-cooled channel is arranged inside the water-cooled radiator, and the annular water-cooled channel is connected with an external water-cooled system through a water inlet pipe and a water outlet pipe which are arranged on the water-cooled radiator;

the indoor deflection coil assembly is used for deflecting the electron beam output from the anode assembly so that the electron beam reaches the upper surface of the target on one side of the anode assembly.

Furthermore, the outer wall of one end of the water-cooled radiator is in threaded connection with the inner wall of the insulator, the outer wall of the other end of the water-cooled radiator is in threaded connection with the inner wall of the conductive sleeve ring, and the middle protruding part extends into the ceramic sleeve to abut against the rhenium hexaboride cathode;

the outer wall of the metal cathode is in threaded connection with the inner wall of the conductive lantern ring.

Furthermore, the surface of the metal cathode, which is in contact with the water-cooled radiator, is coated with heat-conducting silicone grease.

Furthermore, a high-voltage input connecting terminal is arranged in the water-cooled radiator and used for connecting the cathode assembly with a negative high-voltage power supply;

the anode assembly is grounded so as to form an accelerating electric field with the cathode assembly.

Further, the anode assembly comprises an anode body, one end of the anode body is clamped at the end part of the electron gun shell, the other end of the anode body extends into the interior of the electron gun shell, wherein,

an anode hole for passing an electron beam is arranged on the central axis of the anode main body;

an annular water channel is arranged in the anode main body and is connected with an external water cooling system through an anode water inlet pipe and an anode water outlet pipe which are arranged on the anode main body;

the outer wall of the anode main body is provided with an air duct, and the inner side of the anode main body is provided with an air outlet.

Furthermore, a partition plate is arranged inside the annular water channel, and the anode water inlet pipe and the anode water outlet pipe are respectively located on two sides of the partition plate.

Furthermore, the indoor deflection coil assembly comprises a focusing coil, a first deflection coil and a scanning coil which are arranged close to the anode assembly in sequence, a second deflection coil which is arranged at an included angle of 45 degrees with the scanning coil, and a permanent magnet deflection magnetic field which is arranged between the second deflection coil and the target material.

Further, the second deflection coil adopts a symmetrical pole shoe coil structure.

Further, the indoor deflection coil assembly comprises a focusing coil, a scanning coil and a second deflection coil which are sequentially arranged close to the anode assembly, and a permanent magnet deflection magnetic field arranged between the second deflection coil and the target.

Further, the second deflection coil adopts a pair of planar spiral structures.

In conclusion, the water cooling channel is arranged in the cathode assembly, so that the long-term stable work of the cathode assembly is guaranteed, the service life of the cathode assembly is greatly prolonged, the replacement frequency of the cathode assembly is reduced, and the coating quality is effectively improved; through the metal cathode, the reverse spherical surface and the rhenium hexaboride cathode, secondary electrons emitted by the cathode assembly can be concentrated on the surface of the rhenium hexaboride cathode, the beam spot diameter of an electron beam output by the cold cathode electron gun device can be obviously reduced, and the energy density distribution of the beam spot is improved; the current flowing through the indoor deflection coil assembly is adjusted in size and direction, so that the requirements of vertical inverted installation or horizontal installation of the cold cathode electron gun device on the wall of the vacuum chamber can be met, and the output deflection of the electron beam reaches 90-180 degrees and reaches the upper surface of the target.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic view showing the structure of a cold cathode electron gun apparatus for coating according to a first embodiment of the present invention.

Fig. 2 is a schematic view of the structure of the cathode assembly of fig. 1.

Fig. 3 is a schematic view of the installation of the anode assembly of fig. 1.

Fig. 4 is a top view of the anode assembly of fig. 3.

Fig. 5 is a schematic view of the structure of the second deflection coil of fig. 1.

FIG. 6 is a schematic structural view of a cold cathode electron gun apparatus for coating according to a second embodiment of the present invention.

Fig. 7 is a schematic view of the structure of the second deflection coil of fig. 6.

In the figure:

1-a cathode assembly; a 100-rhenium hexaboride cathode; 1000-outdoor gun body assembly; 101-a ceramic sleeve; 102-a metal cathode; 103-a conductive collar; 104-a water-cooled radiator; 105-a water outlet pipe; 106-water inlet pipe; 107-high voltage connection terminals; 2-an insulator; 3-electron gun housing; 4-an anode assembly; 400-an anode body; 401-anode water inlet pipe; 402-anode outlet pipe; 403-airway tube; 404-annular water channel; 405-an air outlet; 406-anode holes; 407-a threaded hole; 5-a focusing coil; 6-a first deflection coil; 7-a scanning coil; 8-a second deflection coil; 9-permanent magnet deflection magnetic field; 10-an electron beam; 11-a target material; 12-a fixed collar; 2000-indoor deflection coil assembly.

Detailed Description

The embodiments of the present invention will be described in further detail with reference to the drawings and examples. The following detailed description of the embodiments and the accompanying drawings are provided to illustrate the principles of the invention and are not intended to limit the scope of the invention, i.e., the invention is not limited to the embodiments described, but covers any modifications, alterations, and improvements in the parts, components, and connections without departing from the spirit of the invention.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

Referring to fig. 1 to 5, a cold cathode electron gun device for coating according to a first embodiment of the present invention includes an outdoor gun body assembly 1000 and an indoor deflection coil assembly 2000, wherein one end of the exterior of an electron gun housing 3 of the outdoor gun body assembly 1000 is mounted with a fixing collar 12, and the other end thereof is fixed on a wall of a vacuum chamber by a flange and connected to the indoor deflection coil assembly 2000 in the vacuum chamber; a cathode component 1 is arranged at one end of the interior of the electron gun shell 3, an anode component 4 is arranged at the other end of the interior of the electron gun shell, the cathode component 1 is connected with a fixed lantern ring 12 through an insulator 2, wherein,

the cathode assembly 1 comprises a conductive sleeve ring 103 coaxially mounted with the insulator 2, and a water-cooling radiator 104 and a metal cathode 102 which are connected with the inner wall of the conductive sleeve ring 103, wherein one end of the metal cathode 102, which faces the anode assembly 4, is concave to form an inverted spherical surface, the other end of the metal cathode is concave and is embedded into a ceramic sleeve 101, a rhenium hexaboride cathode 100 is mounted in the ceramic sleeve 101, a sealed annular water-cooling channel is arranged inside the water-cooling radiator 104, and the annular water-cooling channel is connected with an external water-cooling system through a water inlet pipe 106 and a water outlet pipe 105 which are arranged on the water-cooling radiator 104;

the indoor deflection coil assembly is configured to deflect the electron beam 10 output from the anode assembly 4 so that the electron beam 10 reaches an upper surface of a target 11 located on a side of the anode assembly 4.

In this embodiment, the insulator 2 is used to fixedly mount the cathode assembly 1, so as to ensure the voltage resistance between the cathode assembly 1 and the electron gun housing 3. And a sealing ring 13 is arranged between the insulator 2, the fixed sleeve ring 12 and the electron gun shell 3, so that the vacuum degree in the electron gun is guaranteed.

Referring to fig. 1 and fig. 2, an outer wall of one end of the water-cooled heat sink 104 is in threaded connection with an inner wall of the insulator 2, an outer wall of the other end of the water-cooled heat sink is in threaded connection with an inner wall of the conductive collar 103, and a middle protruding portion extends into the ceramic sleeve 101 to abut against the rhenium hexaboride cathode 100;

the outer wall of the metal cathode 102 is in threaded connection with the inner wall of the conductive collar 103, that is, the inner wall of the conductive collar 103 is simultaneously connected with the metal cathode 102 and the water-cooled heat sink 104, so that the metal cathode 102 and the water-cooled heat sink 104 are at the same potential.

Specifically, the upper surface of the metal cathode 102 is a smooth plane so as to be closely attached to the surface of the water-cooled heat sink 104, and the lower surface is a smooth spherical-inverted surface structure so as to form an accelerating electric field, which is used for primarily converging and accelerating the secondary electrons emitted by the cathode assembly 1. The lower surface of the ceramic sleeve 101 is provided with an annular boss to ensure that the rhenium hexaboride cathode 100 does not fall from the ceramic sleeve 101. The part of the metal cathode 102 embedded in the ceramic sleeve 101 is provided with a boss, so that the ceramic sleeve 101 can be fixed. The middle of the lower surface of the water-cooled radiator 104 is provided with a circular boss, the surface of the circular boss is closely attached to the upper surface of the rhenium hexaboride cathode 100, and negative high-voltage energy is transmitted to the rhenium hexaboride cathode 100.

In a preferred embodiment, the surface of the metal cathode 101 in contact with the water-cooled heat sink 104 is coated with heat-conducting silicone grease to ensure that the heat-conducting silicone grease is closely attached to the lower surface of the water-cooled heat sink 104 for rapid heat dissipation.

Referring to fig. 1 and 2, a high voltage input connection terminal 107 is disposed in the water-cooled heat sink 104, and the high voltage input connection terminal 107 is used for connecting the cathode assembly 1 with a negative high voltage power supply;

the anode assembly 4 is grounded so as to form an accelerating electric field between the anode assembly and the cathode assembly 1, and the accelerating electric field primarily converges and accelerates the secondary electrons emitted by the cathode assembly 1.

Referring to fig. 1 and 3, the anode assembly 4 includes an anode main body 400, one end of the anode main body 400 is clamped at the end of the electron gun housing 3, and the other end extends into the interior of the electron gun housing 3, wherein,

an anode hole 406 through which an electron beam passes is provided at the central axis of the anode body 400;

an annular water channel 404 is arranged in the anode main body 400, and the annular water channel 404 is connected with an external water cooling system through an anode water inlet pipe 401 and an anode water outlet pipe 402 which are arranged on the anode main body 400;

the outer wall of the anode main body 400 is provided with an air duct 403, and the inner side is provided with an air outlet 405.

The gas duct 403 is used to introduce the discharge gas into a chamber formed between the cathode assembly 1, the electron gun housing 3, and the anode assembly 4 inside the electron gun apparatus.

As a preferred embodiment, a partition is disposed inside the annular water channel 404, and the anode water inlet pipe 401 and the anode water outlet pipe 402 are respectively located at two sides of the partition to prevent mutual interference between water inlet and outlet.

Referring to fig. 1 and 4, the anode main body 400 is provided with an outer flange, a plurality of threaded holes 407 are uniformly distributed on the outer flange, the outer flange is connected with a flange arranged at the lower end of the electron gun housing 3 by bolts penetrating through the threaded holes 407, and a sealing ring is arranged between the outer flange and the flange arranged at the lower end of the electron gun housing 3 to ensure the vacuum degree inside the electron gun device.

The flange is detachably connected with the wall of the vacuum chamber through bolts, so that the electron gun shell is fixed on the vacuum chamber,

referring to fig. 1 and 5, the indoor deflection coil assembly includes a focusing coil 5, a first deflection coil 6, and a scanning coil 7, which are sequentially disposed adjacent to the anode assembly 4, a second deflection coil 8 disposed at an angle of 45 ° with respect to the scanning coil 7, and a permanent magnet deflection magnetic field 9 disposed between the second deflection coil 8 and the target 11.

In the present embodiment, the focusing coil 5, the first deflection coil 6, and the scanning coil 7 are coaxially and vertically mounted on the insulator 2, the cathode assembly 1, and the anode assembly 4, and the focusing coil 5, the first deflection coil 6, and the scanning coil 7 are all mounted inside the vacuum chamber. The first deflection coil 6 provides a magnetic field which is vertically injected into the paper; the scanning coils 7 comprise two groups of coils in the X direction and the Y direction, and sine wave current and cosine wave current with the same amplitude and frequency are respectively introduced, so that the electron beam 10 scans the heating area of the target 11 in a circular track, and the target is ensured to be uniformly heated and evaporated; the second deflection coil 8 adopts a symmetrical pole shoe coil structure and provides a magnetic field which is vertically emitted into the paper.

The specific process is as follows: the electron beam 10 is output from the anode hole 406, focused by the focusing coil 5, and deflected by 45 degrees to the left by the first deflection coil 6; after the electron beam 10 is deflected 45 degrees leftwards again by the second deflection coil 8, the electron beam reaches the permanent magnet deflection magnetic field 9, and the permanent magnet deflection magnetic field 9 generates a uniform magnetic field which is vertically shot into the paper surface, so that the electron beam 10 is deflected 90 degrees again to reach the upper surface of the target 11.

It should be further noted that, in other embodiments, the first deflection coil 6, the second deflection coil 8, and the permanent magnet deflection magnetic field 9 can also generate a uniform magnetic field that is vertically emitted out of the paper, so that the electron beam 10 can be deflected by 180 ° to the right after being output from the anode hole 406, so as to meet the requirements of other installation manners.

Referring to fig. 6 and 7, a cold cathode electron gun apparatus for coating according to a second embodiment of the present invention is different from the first embodiment in an indoor deflection yoke assembly.

Specifically, the indoor deflection coil assembly 2000 includes a focusing coil 5, a scanning coil 7, and a second deflection coil 8, which are sequentially disposed next to the anode assembly 4, and a permanent magnet deflection magnetic field 9 disposed between the second deflection coil 8 and the target 11.

In this embodiment, the second deflection coil 8 and the scanning coil 7 are horizontally disposed. The scanning coils 7 comprise two groups of coils in the X direction and the Y direction, and sine wave current and cosine wave current with the same amplitude and frequency are respectively introduced into the coils, so that the electron beams 10 scan the heating area of the target 11 in a circular shape, and the target is ensured to be uniformly heated and evaporated; the second deflection coil 8 adopts a pair of planar spiral structures which can be wound into a circle or a square, and the second deflection coil 8 provides a magnetic field which is vertically injected into a paper surface.

The specific process is as follows: the electron beam 10 is output from the anode hole 406, focused by the focusing coil 5, and deflected by 90 ° by the second deflection coil 8 to reach the permanent magnet deflection magnetic field 9, and the permanent magnet deflection magnetic field 9 generates a uniform magnetic field vertically incident on the paper surface, so that the electron beam 10 is deflected by 90 ° again to reach the upper surface of the target 11.

It should be further noted that, in other embodiments, the second deflection coil 8 and the permanent magnet deflection magnetic field 9 can also generate a uniform magnetic field that is vertically emitted out of the paper surface, so that the electron beam 10 can be deflected by 180 ° to the right after being output from the anode hole 406, so as to meet the requirements of other installation manners.

In conclusion, the water cooling channel is arranged in the cathode assembly 1, so that the long-term stable work of the cathode assembly 1 is guaranteed, the service life of the cathode assembly 1 is greatly prolonged, the replacement frequency of the cathode assembly 1 is reduced, and the coating quality is effectively improved; through the metal cathode 102, the reverse spherical surface and the rhenium hexaboride cathode 100, secondary electrons emitted by the cathode assembly 1 can be concentrated on the surface of the rhenium hexaboride cathode 100, the beam spot diameter of an electron beam output by a cold cathode electron gun device can be obviously reduced, and the energy density distribution of the beam spot is improved; the cold cathode electron gun device can be vertically and inversely installed or horizontally installed on the wall of the vacuum chamber by adjusting the magnitude and the direction of current flowing through each coil of the indoor deflection coil assembly 2000, so that the electron beam is deflected by 90-180 degrees to reach the upper surface of the target.

It should be clear that the embodiments in this specification are described in a progressive manner, and the same or similar parts in the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. For embodiments of the method, reference is made to the description of the apparatus embodiments in part. The present invention is not limited to the specific steps and structures described above and shown in the drawings. Also, a detailed description of known process techniques is omitted herein for the sake of brevity.

The above description is only an example of the present application and is not limited to the present application. Various modifications and alterations to this application will become apparent to those skilled in the art without departing from the scope of this invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.