1. A mask plate structure is characterized by comprising a mask plate frame and alignment mask strips;

the mask plate frame comprises a first surface and a second surface which are oppositely arranged, the first surface is the surface opposite to a substrate to be evaporated in the evaporation process, and a plurality of alignment grooves are arranged on the first surface of the mask plate frame at intervals;

the alignment mask strip comprises a supporting part and a special-shaped alignment part, the special-shaped alignment part comprises an alignment block located in the alignment groove and connecting blocks extending from two ends of the alignment block to the direction of the first surface respectively, the alignment block is connected with the supporting part through the connecting blocks, and the supporting part is located on the first surface.

2. The mask structure according to claim 1, wherein a thickness of the alignment block in a direction perpendicular to the first surface is smaller than a depth of the alignment groove.

3. The mask structure according to claim 1, wherein a distance d ≠ k ≠ λ/n between a side of the alignment block near the first surface and the first surface in a direction perpendicular to the first surface, where k is an extinction coefficient, λ is a wavelength, and n is a refractive index.

4. The mask structure according to claim 1, wherein a gap exists between the alignment block and a side edge of the alignment groove.

5. The mask structure according to claim 1, wherein a bottom surface of the alignment groove is provided with a first land, and the alignment block is provided with a second land corresponding to the first land, and the alignment block is fixed to the bottom surface of the alignment groove by the first land and the second land.

6. The mask blank structure according to claim 1, further comprising a fine metal mask and a support bracket for supporting the fine metal mask, the fine metal mask and the support bracket being fixed to the mask frame at one side of the alignment groove.

7. A method of making a mask plate structure, the method comprising:

providing a mask plate frame, wherein the mask plate frame comprises a first surface and a second surface which are oppositely arranged, and the first surface is the surface opposite to a substrate to be evaporated in the evaporation process;

forming a plurality of alignment grooves which are recessed towards the second surface from the first surface of the mask frame;

manufacturing and forming an alignment mask strip with special-shaped alignment parts corresponding to the alignment grooves respectively, and forming a supporting part for supporting the special-shaped alignment parts between the adjacent special-shaped alignment parts, wherein each special-shaped alignment part comprises an alignment block and connecting blocks extending from two ends of the alignment block to the supporting part respectively;

and fixedly arranging the alignment block in the alignment groove, so that the connecting blocks respectively extend from two ends of the alignment block to the direction of the first surface, the alignment block is connected with the supporting part through the connecting blocks, and the supporting part is in contact with the first surface.

8. The method of manufacturing a mask plate structure according to claim 7, wherein the step of forming the alignment mask stripes having the irregular alignment portions corresponding to the respective alignment grooves comprises:

providing a mask strip body;

performing a first etching process from the first surface of the mask strip body and the position corresponding to the alignment groove to form etching grooves corresponding to the alignment groove respectively;

and carrying out a second etching process from the position of the second surface of the mask strip body on the peripheral side of the etching groove to form the special-shaped counterpoint part at the position corresponding to the etching groove, wherein the second surface is opposite to the first surface.

9. The method of manufacturing a mask plate structure according to claim 7, wherein the step of forming the alignment mask stripes having the irregular alignment portions corresponding to the respective alignment grooves comprises:

providing an electroforming mold with a shape matched with the shape of the alignment mask strip;

and performing metal electroforming based on the electroforming mold to form the alignment mask strips with the special-shaped alignment parts.

10. The method of manufacturing a mask plate structure according to any one of claims 7-9, further comprising:

after the alignment block is fixedly arranged in the alignment groove, the alignment mask strip is cut, and the supporting part and the connecting block are removed.

Background

In the manufacturing process of an OLED (Organic Light Emitting Diode) display panel, a mask plate structure is usually used to control the evaporation pixels in the pixel evaporation process. For guaranteeing that mask slice can be accurate with the relative position of treating the coating by vaporization base plate, can weld the coating by vaporization counterpoint part that is used for counterpointing on mask slice usually, thereby counterpoint through counterpoint sign and the counterpoint sign on the coating by vaporization counterpoint part of treating on the coating by vaporization base plate in the pixel coating by vaporization in-process and guarantee that both relative positions are accurate.

However, most of the existing designs for the evaporation positioning part are directly contacted with the substrate to be evaporated to realize alignment matching, and the design can have adverse effects on the service life of the mask. For example, after the evaporation positioning part is used for a certain time, the evaporation positioning part is unstable due to friction generated in the alignment process, so that the water ripple phenomenon occurs when the lens is grabbed, and the evaporation positioning precision is affected.

Disclosure of Invention

Based on the defects of the existing design, the application provides a mask plate structure and a preparation method of the mask plate structure.

According to a first aspect of the present application, a mask structure is provided, which includes a mask frame and alignment mask bars;

the mask plate frame comprises a first surface and a second surface which are oppositely arranged, the first surface is the surface opposite to a substrate to be evaporated in the evaporation process, and a plurality of alignment grooves are arranged on the first surface of the mask plate frame at intervals;

the alignment mask strip comprises a supporting part and a special-shaped alignment part, the special-shaped alignment part comprises an alignment block located in the alignment groove and connecting blocks extending from two ends of the alignment block to the direction of the first surface respectively, the alignment block is connected with the supporting part through the connecting blocks, and the supporting part is located on the first surface.

In a possible embodiment of the first aspect, a thickness of the alignment block in a direction perpendicular to the first surface is smaller than a depth of the alignment groove.

In a possible embodiment of the first aspect, a distance d ≠ k ×/n between a side of the alignment block near the first surface and the first surface in a direction perpendicular to the first surface, where k is an extinction coefficient, λ is a wavelength, and n is a refractive index.

In one possible embodiment of the first aspect, a gap exists between the alignment block and a side edge of the alignment groove.

In one possible embodiment of the first aspect, a bottom surface of the alignment groove is provided with a first land, the alignment block is provided with a second land corresponding to the first land, and the alignment block is fixed to the bottom surface of the alignment groove by the first land and the second land.

In one possible implementation manner of the first aspect, the mask blank structure further includes a fine metal mask and a support frame for supporting the fine metal mask, and the fine metal mask and the support frame are fixed to the mask blank frame at one side of the alignment groove.

According to a second aspect of the present application, there is provided a method of manufacturing a mask plate structure, the method comprising:

providing a mask plate frame, wherein the mask plate frame comprises a first surface and a second surface which are oppositely arranged, and the first surface is the surface opposite to a substrate to be evaporated in the evaporation process;

forming a plurality of alignment grooves which are recessed towards the second surface from the first surface of the mask frame;

manufacturing and forming an alignment mask strip with special-shaped alignment parts corresponding to the alignment grooves respectively, and forming a supporting part for supporting the special-shaped alignment parts between the adjacent special-shaped alignment parts, wherein each special-shaped alignment part comprises an alignment block and connecting blocks extending from two ends of the alignment block to the supporting part respectively;

and fixedly arranging the alignment block in the alignment groove, so that the connecting blocks respectively extend from two ends of the alignment block to the direction of the first surface, the alignment block is connected with the supporting part through the connecting blocks, and the supporting part is in contact with the first surface.

In one possible embodiment of the second aspect, the manufacturing of the alignment mask stripes having the irregularly-shaped alignment portions corresponding to the respective alignment grooves includes:

providing a mask strip body;

performing a first etching process from the first surface of the mask strip body and the position corresponding to the alignment groove to form etching grooves corresponding to the alignment groove respectively;

and carrying out a second etching process from the position of the second surface of the mask strip body on the peripheral side of the etching groove to form the special-shaped counterpoint part at the position corresponding to the etching groove, wherein the second surface is opposite to the first surface.

In one possible embodiment of the second aspect, the manufacturing of the alignment mask stripes having the irregularly-shaped alignment portions corresponding to the respective alignment grooves includes:

providing an electroforming mold with a shape matched with the shape of the alignment mask strip;

and performing metal electroforming based on the electroforming mold to form the alignment mask strips with the special-shaped alignment parts.

In one possible implementation of the second aspect, the method further comprises:

after the alignment block is fixedly arranged in the alignment groove, the alignment mask strip is cut, and the supporting part and the connecting block are removed.

Based on any one of the above aspects or any one of the possible implementation manners of any aspect, in the present application, a mask frame and alignment mask bars are provided, and a plurality of alignment grooves are provided at intervals on a first surface of the mask frame opposite to a substrate to be vapor-deposited in a vapor deposition process, each alignment mask bar includes a supporting portion and a special-shaped alignment portion, each special-shaped alignment portion includes an alignment block located in each alignment groove and connecting blocks extending from two ends of the alignment block to the direction of the first surface, each alignment block is connected with the supporting portion through the connecting blocks, and the supporting portion is located on the first surface. So, through to counterpoint mask strip design dysmorphism counterpoint portion, can be so that actual counterpoint portion forms the difference in height with a net part, avoid this counterpoint portion and treat that the coating by vaporization base plate contacts and lead to the coating by vaporization counterpoint portion unstable to counterpoint recess and this counterpoint portion one-to-one on the mask slice frame need not to carry out whole face fluting to whole counterpoint mask strip, consequently the fluting area is littleer, thereby can promote the mechanical strength of mask slice frame. In addition, the special-shaped aligning part is connected with the supporting part, and the supporting part and the surface of the mask plate frame form a support, so that the aligning mask strips can be normally stressed in the screen-stretching process.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and it will be apparent to those skilled in the art that other related drawings can be obtained from the drawings without inventive effort.

Fig. 1 is a schematic structural diagram illustrating a mask plate structure provided in an embodiment of the present application;

fig. 2 is a schematic flow chart of a method for manufacturing a mask plate structure according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram of a preparation structure of step S110 shown in FIG. 2;

FIG. 4 is a schematic diagram of a preparation structure of step S120 shown in FIG. 2;

FIG. 5 is a schematic diagram illustrating a preparation structure of step S140 shown in FIG. 2;

FIG. 6 is a schematic diagram of a preparation structure of step S150 shown in FIG. 2;

FIG. 7 shows one of the sub-step flow diagrams of step S130 shown in FIG. 2;

fig. 8 shows a schematic view of a preparation structure of step S131a shown in fig. 7;

fig. 9 shows a schematic view of a preparation structure of step S132a shown in fig. 7;

fig. 10 shows a schematic view of a preparation structure of step S133a shown in fig. 7;

FIG. 11 shows a second schematic flow chart of the sub-steps of step S130 shown in FIG. 2;

fig. 12 is a second schematic flow chart illustrating a method for manufacturing a mask plate structure according to an embodiment of the present disclosure;

fig. 13 shows a schematic diagram of a preparation structure of step S150 shown in fig. 12.

Detailed Description

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it should be understood that the drawings in the present application are for illustrative and descriptive purposes only and are not used to limit the scope of protection of the present application. Additionally, it should be understood that the schematic drawings are not necessarily drawn to scale. The flowcharts used in this application illustrate operations implemented according to some of the embodiments of the present application.

As mentioned in the above background art, the inventor of the present application finds, in a research process, that in an evaporation process of the related art, a substrate to be evaporated (e.g., a glass substrate) is generally attached above a mask plate and directly contacts with alignment mask bars, so that after the alignment mask bars are pressed for many times and for a long time, some alignment holes on the alignment mask bars may be shifted in position, which results in a decrease in alignment accuracy and repeatability. For example, the surface topography of the alignment holes under the lens of the image capture device may also change, which may cause a ripple phenomenon when the lens captures the alignment holes, thereby causing a gradual decrease in the accuracy of the mask plate structure and the substrate to be vapor-deposited.

In order to improve the above problems, in the related art, a plurality of grooves may be formed on the mask frame, for example, a full-surface grooving design is performed for the alignment mask bars corresponding to the mesh-opening direction, and the alignment mask bars are disposed in the grooves, and meanwhile, the thickness of the alignment mask bars is smaller than the depth of the grooves. However, the slotted design may also cause large sagging of the reticle frame, which may have a large impact on the mechanical strength of the reticle frame.

It should be noted that the above prior art solutions have shortcomings which are the results of practical and careful study of the inventor, therefore, the discovery process of the above technical problems and the solutions proposed by the following embodiments of the present application for the above problems should be the contribution of the inventor to the present application in the course of the invention creation process, and should not be understood as technical contents known by those skilled in the art.

Based on the above technical problems discovered by the inventors, embodiments of the present application provide an improved mask plate structure to improve the above problems.

In detail, the mask plate structure of the embodiment of the present application includes a mask plate frame and alignment mask bars. The mask plate frame comprises a first surface and a second surface which are arranged oppositely, the first surface is the surface opposite to the substrate to be evaporated in the evaporation process, and a plurality of alignment grooves are arranged on the first surface of the mask plate frame at intervals. Wherein, counterpoint mask strip includes supporting part and dysmorphism counterpoint portion, and dysmorphism counterpoint portion is including the counterpoint piece that is located counterpoint recess and the connecting block that extends from the both ends of counterpoint piece toward the direction of first surface respectively, and the counterpoint piece passes through the connecting block to be connected with the supporting part, and the supporting part is located the first surface.

From this design, through to counterpoint mask strip design dysmorphism counterpoint portion, can be so that actual counterpoint portion forms the difference in height with a net part, avoid this counterpoint portion and treat that the coating by vaporization base plate contacts and lead to the coating by vaporization counterpoint portion unstable to counterpoint recess and this counterpoint portion one-to-one on the mask slice frame need not to carry out whole face fluting to whole counterpoint mask strip, consequently the fluting area is littleer, thereby can promote the mechanical strength of mask slice frame. In addition, the special-shaped aligning part is connected with the supporting part, and the supporting part and the surface of the mask plate frame form a support, so that the aligning mask strips can be normally stressed in the screen-stretching process.

Some exemplary implementations of the curved cover plate fixture will be described in detail below with reference to the drawings and specific alternative embodiments.

Referring to fig. 1, a mask structure 100 according to an embodiment of the present disclosure is provided, where the mask structure 100 may include a mask frame 110 and alignment mask bars 120.

In one possible embodiment, the mask frame 110 may be made of, but not limited to, one or more of nickel-iron, nickel-cobalt, stainless steel, or invar, or the mask frame 110 may be made of other materials that can withstand evaporation or etching.

In this embodiment, as shown in fig. 1, the mask frame 110 may include a first surface 111 and a second surface 112 that are oppositely disposed, for example, the first surface 111 may be a surface opposite to the substrate to be evaporated during the evaporation process, and the second surface 112 may be a surface away from the substrate to be evaporated during the evaporation process. In order to facilitate vapor deposition alignment, a plurality of alignment grooves 113 may be disposed on the first surface 111 of the mask frame 110 at intervals.

In this embodiment, the alignment mask strip 120 may include a supporting portion 121 and a special-shaped alignment portion 122, the special-shaped alignment portion 122 includes an alignment block 1221 located in the alignment groove 113 and connection blocks 1222 extending from two ends of the alignment block 1221 toward the first surface 111, the alignment block 1221 is connected to the supporting portion 121 through the connection blocks 1222, and the supporting portion 121 is located on the first surface 111. For example, the connection blocks 1222 may extend from both ends of the alignment block 1221 in a direction perpendicular to the extending direction of the alignment block 1221 toward the first surface 111.

In this embodiment, the positioning portion is used to realize the alignment connection between the mask plate structure 100 and the substrate to be evaporated, and the specific positioning portion may be a structure protruding from the light-emitting surface, or the positioning portion may also be a structure recessed from the light-emitting surface. Wherein each alignment portion can be laid on the mask frame 110 by a screen process.

In one possible embodiment, one or more alignment marks may be disposed on the alignment block 1221, and the specific structure of the alignment marks may be various, for example, a plurality of alignment marks are uniformly disposed on each alignment block 1221, and the alignment marks may be through holes disposed through the alignment block 1221, but not limited thereto.

In one possible embodiment, the alignment grooves 113 may have a suitable depth that does not penetrate the reticle frame 110. When pixel evaporation is required, the alignment groove 113 of the mask frame 110 and the substrate to be evaporated can be aligned accurately. After the alignment groove 113 and the substrate to be evaporated are aligned accurately, a pixel evaporation process can be performed on the substrate to be evaporated.

In a possible embodiment, the cross section of the inner wall of the alignment groove 113 may be a curve or a straight line, or a combination of the curve and the straight line, and may specifically vary according to the design requirement of the mask frame 110.

Based on the above design, this embodiment can make actual counterpoint portion and the part of opening the net form the difference in height through designing dysmorphism counterpoint portion 122 to counterpoint mask strip 120, avoids this counterpoint portion and waiting to evaporate the substrate and contact and lead to evaporating deposition counterpoint portion unstability to counterpoint recess 113 on mask plate frame 110 corresponds with this counterpoint portion one-to-one, need not to carry out whole face fluting to whole counterpoint mask strip 120, therefore the fluting area is littleer, thereby can promote mask plate frame 110's mechanical strength. In addition, by connecting the special-shaped aligning portion 122 with the supporting portion 121, the supporting portion 121 forms a support with the surface of the mask frame 110, so that the aligning mask strips 120 can be normally stressed during the screen-stretching process.

That is to say, the counterpoint mask strip 120 that this application provided only needs to counterpoint through counterpoint piece 1221 by vaporization, compare in the scheme that adopts whole counterpoint mask strip 120 to carry out the coating by vaporization counterpoint among the correlation technique, the fluting area is littleer, mechanical influence to mask blank frame 110's mechanical strength is littleer, and contact with counterpoint piece 1221 not direct with treating the coating by vaporization base plate, thereby avoid counterpoint piece 1221 in counterpoint process with treat that the coating by vaporization base plate produces the friction and lead to the coating by vaporization counterpoint part unstable, influence the problem of coating by vaporization counterpoint precision. In addition, in a specific vapor deposition alignment process, when the substrate to be vapor deposited is in contact with the supporting portion 121 for supporting, the generated stress can be further buffered by the connecting blocks 1222 on both sides, so that the stress influence of the stress generated by the contact of the substrate to be vapor deposited with the supporting portion 121 for supporting on the surface of the alignment block 1221 is reduced, the stability of the vapor deposition alignment portion is further improved, and the vapor deposition alignment accuracy is ensured.

In one possible embodiment, the thickness of the alignment block 1221 in the direction perpendicular to the first surface 111 is smaller than the depth of the alignment groove 113. That is, the depth of the alignment groove 113 is greater than the thickness of the alignment block 1221, and the depth of the alignment groove 113 is the distance from the bottom of the alignment groove 113 to the first surface 111. By such design, the alignment block 1221 is not higher than the first surface 111 all the time, so that a height difference is formed between the actual alignment part and the mesh part, and instability of the evaporation alignment part due to contact between the alignment part and the substrate to be evaporated in the subsequent alignment process is avoided.

In one possible embodiment, in order to ensure that the image capturing device does not interfere with the lens during the vapor deposition alignment, the distance d ≠ k λ/n between the side of the alignment block 1221 close to the first surface 111 and the first surface 111 in the direction perpendicular to the first surface 111, where k is the extinction coefficient, λ is the wavelength, and n is the refractive index. For example, in practical tests, the distance d between the side of the alignment block 1221 close to the first surface 111 and the first surface 111 may be greater than the sum of the manufacturing accuracy of the reticle structure 100 and 20 um.

In a possible embodiment, in order to ensure that a certain stretching precision margin is left between the alignment block 1221 and the edge of the alignment groove 113, it is ensured that the alignment block 1221 can be partially and completely placed in the alignment groove 113, a gap may exist between the alignment block 1221 and the edge of the alignment groove 113, and the size of the gap may be set according to actual design requirements, which is not particularly limited in this embodiment.

In one possible embodiment, a first welding region may be disposed on the bottom surface of the alignment recess 113, a second welding region (not shown) corresponding to the first welding region may be disposed on the alignment block 1221, and the alignment block 1221 may be fixed to the bottom surface of the alignment recess 113 by the first welding region and the second welding region. For example, the second welding areas on the alignment portion may be adjusted to a predetermined position of the alignment groove 113, the second welding areas on both ends of the alignment portion may be heated, the alignment portion may be welded in the alignment groove 113, and after the welding is completed, the positions on both sides of the welding areas of the alignment groove 113 may be cut off by laser.

In a possible embodiment, the mask plate structure 100 may further include a fine metal mask and a support frame (not shown in the figure), wherein the support frame is used for supporting the fine metal mask, so as to prevent the middle position of the fine metal mask from sagging due to gravity, and ensure that the fine metal mask is attached to the substrate to be evaporated. The fine metal mask and the supporter are fixed to the mask frame 110 at one side of the alignment groove 113. The fine metal mask may include a mask pattern region and a non-mask pattern region for forming a light emitting layer in a pixel region corresponding to the OLED to achieve evaporation pixel control. The substrate to be evaporated may include display regions corresponding to the mask pattern regions one to one and standard evaporation regions corresponding to the alignment holes of the alignment block 1221 one to one. When the alignment holes and the standard evaporation area are aligned in a pair, the mask pattern area and the display area are aligned in a pair. The alignment mask bars 120, the supports, and the fine metal mask may be fixed on the mask frame 110 by a screen process, and the fine metal mask is overlapped over the supports.

Further, based on the same inventive concept, please refer to fig. 2 in combination, an embodiment of the present application further provides a method for manufacturing a mask blank structure 100, and a flowchart is used in this specification to describe operations performed according to embodiments of the present specification. It should be understood that the preceding or following operations are not necessarily performed in the exact order in which they are performed. Rather, the various steps may be processed in reverse order or simultaneously. Meanwhile, other operations may be added to the processes, or a certain step or operations may be removed from the processes. The method for manufacturing the mask blank structure 100 will be explained in detail below with reference to the drawings.

Referring to fig. 3, in step S110, a mask frame 110 is provided, where the mask frame 110 includes a first surface 111 and a second surface 112 that are disposed opposite to each other, and the first surface 111 is a surface opposite to a substrate to be evaporated during an evaporation process.

Referring to fig. 4, in step S120, a plurality of alignment grooves 113 recessed toward the second surface 112 are formed on the first surface 111 of the mask frame 110.

Referring to fig. 5, in step S130, the alignment mask stripes 120 having the irregular alignment portions 122 corresponding to the respective alignment grooves 113 are formed, the supporting portions 121 supporting the irregular alignment portions 122 are formed between the adjacent irregular alignment portions 122, and the irregular alignment portion 122 includes an alignment block 1221 and connecting blocks 1222 extending from two ends of the alignment block 1221 to the supporting portions 121.

Referring to fig. 6, in step S140, the alignment block 1221 is fixedly disposed in the alignment groove 113, such that the connection blocks 1222 extend from two ends of the alignment block 1221 toward the first surface 111, the alignment block 1221 is connected to the supporting portion 121 through the connection blocks 1222, and the supporting portion 121 contacts the first surface 111.

For the above step S130, two possible examples are provided below to explain the specific preparation process of the reticle strips 120. For example, in one possible implementation, please refer to fig. 7 in combination, step S130 may be implemented by the following sub-steps.

Referring to fig. 8, in step S131a, a mask strip body 1200 is provided. For example, the shape of the mask bar body 1200 may be a rectangular parallelepiped shape.

Referring to fig. 9, in step S132a, a first etching process (top etching) is performed from the first surface 1201 of the mask strip body 1200 and the position corresponding to the alignment groove 113 to form etching grooves 1203 corresponding to the alignment groove 113 respectively.

Referring to fig. 10, in step S133a, a second etching process (under etching) is performed from a position of the second surface 1202 of the mask strip body 1200 on the periphery of the etching groove 1203, so that the irregular positioning portion 122 is formed at a position corresponding to the etching groove 1203, and the second surface 1203 is opposite to the first surface 1201.

For another example, in another possible implementation, please refer to fig. 11 in combination, step S130 may be implemented by the following sub-steps.

Step S131b, an electroforming mold having a shape matching the shape of the alignment mask bar 120 is provided.

In step S132b, metal electroforming is performed on the electroforming mold to form the alignment mask stripes 120 having the irregular alignment portions 122.

In one possible implementation manner, referring to fig. 12, after step S140, the method for manufacturing the mask blank structure 100 may further include the following steps.

Referring to fig. 13, in step S150, after the alignment block 1221 is fixedly disposed in the alignment groove 113, the alignment mask strip 120 is cut to remove the supporting portion 121 and the connecting block 1222.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this application belongs. The use of "first," "second," and similar terms in the description and in the claims does not indicate any order, quantity, or importance, but rather is used to distinguish one element from another. Also, the use of the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. "plurality" or "a number" means two or more. The word "comprising" or "comprises", and the like, means that the element or item listed as preceding "comprising" or "includes" covers the element or item listed as following "comprising" or "includes" and its equivalents, and does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. As used in this specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

It is to be understood that the specific embodiments described herein are merely illustrative of the application and are not limiting of the application. It should be further noted that, for the convenience of description, only some of the structures related to the present application are shown in the drawings, not all of the structures. In the drawings, the shape and size may be exaggerated for clarity, and the same reference numerals will be used throughout the drawings to designate the same or similar components. Terms concerning attachment, coupling, and the like, refer to a relationship wherein structures are secured or attached, either directly or indirectly, to one another through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise.

The embodiments described above are only a part of the embodiments of the present application, and not all of the embodiments. The components of the embodiments of the present application, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the application, but is merely representative of selected embodiments of the application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims. Moreover, all other embodiments that can be made available by a person skilled in the art without making any inventive step based on the embodiments of the present application shall fall within the scope of protection of the present application.