Mask assembly and preparation method thereof

Abstract

The mask assembly comprises a mask frame, supporting pieces, a precision supporting piece mask plate and a precision metal mask plate which are sequentially arranged from bottom to top, the supporting pieces are arranged on the mask frame and intersect with the precision metal mask plate in an invalid mask area of the precision metal mask plate, and the precision metal mask plate is arranged on the mask frame. The precise supporting piece mask plates are arranged on the mask frame and penetrate through an effective mask area of the precise metal mask plate, and an opening of the precise supporting piece mask plate in the effective mask area is larger than an opening of the precise metal mask plate. The problems that an existing large-size precise metal mask plate droops due to gravity, and wrinkles exist on the edge can be solved.

Description

Technical Field

[0001] The present invention relates to the field of electronic printing, and more particularly to a mask assembly and a method for manufacturing the same. Background Art

[0002] With the rapid development of the display industry towards large size and high resolution, the demand for the size of the fine metal mask (FMM) used in the production of display screens has increased significantly. The mainstream FMM size has gradually expanded to 27 inches and above to meet the production requirements of large-size display panels. However, with the increase in the size of the FMM, the central area of the FMM sags due to gravity and there are wrinkles at the edges. Currently, using only the fine support sheet mask in the non-effective area of the FMM cannot improve the problems of sagging and edge wrinkles of the FMM. To address the above problems, the industry currently optimizes the material system of the fine support sheet mask, but the effect of improving the material strength is limited; or a whole metal support mesh is added to the back of the FMM to provide distributed mechanical support through double mesh bonding. However, the high-precision bonding process between the support mesh and the FMM is difficult to achieve, and the introduction of the support mesh increases the overall thickness and weight, affecting the stability of the display screen manufacturing process. Summary of the Invention

[0003] An object of the present invention is to provide a mask assembly, comprising: a mask frame, a support sheet, a fine support sheet mask, and a fine metal mask arranged in sequence from bottom to top, wherein the support sheet is arranged on the mask frame and intersects with the fine metal mask in the non-effective mask area of the fine metal mask, and the fine support sheet mask is arranged on the mask frame and penetrates through the effective mask area of the fine metal mask, wherein the opening of the fine support sheet mask in the effective mask area is larger than the opening of the fine metal mask.

[0004] Further, the opening shape of the fine support sheet mask is the same as the opening shape of the fine metal mask.

[0005] Further, the opening shape of the fine support sheet mask is a composite shape that simultaneously includes the openings of pixel R, pixel B, and pixel G.

[0006] Further, the thickness of the fine support sheet mask in the first area is greater than the thickness in the second area.

[0007] Further, the centers of gravity of the fine support sheet mask and the fine metal mask intersect.

[0008] Further, the fine support sheet mask is welded to the mask frame, the size of the first solder joint is 200 - 500 um, and the pitch of the first solder joints is 1.5 - 2.5 mm.

[0009] Further, the precision metal mask plate is welded to the mask frame, the size of the second solder joint is 200-400 um, and the pitch of the second solder joints is 1-2 mm.

[0010] Further, the size of the first solder joint is larger than that of the second solder joint, and the first solder joints and the second solder joints are arranged at intervals.

[0011] On the other hand, the present invention provides a method for manufacturing a mask assembly, including: providing a mask frame, a support sheet, a precision support sheet mask plate, and a precision metal mask plate, and sequentially welding the support sheet, the precision support sheet mask plate, and the precision metal mask plate to the mask frame.

[0012] Further, before welding the support sheet, a pre-pressure is applied to the mask frame on the outer periphery of the mask frame.

[0013] The present invention has at least the following advantages or beneficial effects: it can solve the problems of gravity sagging and wrinkles at the edges of the current large-size precision metal mask plate. In this case, a partitioned support design is adopted. The support sheet is placed in the invalid mask area (non-pattern area) of the precision metal mask plate, and the support sheet provides a rigid support at the edge; the precision support sheet mask plate is placed in the effective mask area (pattern area) of the precision metal mask plate, and the precision support sheet mask plate supports the FMM in the central effective area, reducing sagging and wrinkles caused by gravity, realizing partitioned support, significantly reducing the weight of the component while ensuring the support strength, and reducing the requirements for the bonding accuracy process. Description of the Drawings

[0014] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0015] Figure 1 It is a schematic diagram of some components of the mask assembly; Figure 2 It is a cross-sectional view of the mask assembly; Figure 3 It is an enlarged view of the solder joints of the mask assembly.

[0016] 1 - Mask frame; 2 - Support sheet; 3 - Precision support sheet mask plate; 4 - Precision metal mask plate; 11 - Concave platform; 31 - First area; 32 - Second area; 33 - First solder joint; 41 - Second solder joint. Specific Embodiments

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific implementations in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Components of the embodiments of the present invention generally described and illustrated in the drawings herein can be arranged and designed in a variety of different configurations.

[0018] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0019] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is customarily placed during use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and should not be construed as indicating or implying relative importance.

[0020] In addition, terms such as "horizontal" and "vertical" do not mean that the components are required to be absolutely horizontal or hanging vertically, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0021] In the description of the present invention, it should also be noted that unless otherwise clearly defined and limited, the terms "set", "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] By providing a mask assembly in the embodiments of the present application, the problems of gravity sagging and wrinkles at the edges of large-sized precision metal mask plates can be solved. For example Figure 1As shown in the figure, a mask assembly includes: a mask frame 1, a support sheet 2, a precision support sheet mask plate 3, and a precision metal mask plate 4 arranged in sequence from bottom to top. The support sheet 2 is arranged on the mask frame 1 and intersects with the precision metal mask plate 4 at the invalid mask area of the precision metal mask plate 4. The precision support sheet mask plate 3 is arranged on the mask frame 1 and penetrates through the effective mask area of the precision metal mask plate 4. The opening of the precision support sheet mask plate in the effective mask area is larger than that of the precision metal mask plate.

[0023] In this case, a partition support design is adopted. The support sheet 2 is placed in the invalid mask area (non-pattern area) of the precision metal mask plate 4, and the support sheet 2 provides a rigid support effect at the edge. The precision support sheet mask plate 3 is placed in the effective mask area (pattern area) of the precision metal mask plate 4. The precision support sheet mask plate 3 supports the FMM in the central effective area, reduces the sagging and wrinkling caused by gravity, realizes partition support, significantly reduces the weight of the component while ensuring the support strength, and reduces the requirements for the bonding accuracy process.

[0024] In addition, the opening size of the precision support sheet mask plate 3 in the effective mask area is larger than that of the FMM, avoiding blocking the evaporation material path and ensuring the accuracy of the evaporation pattern.

[0025] The precision support sheet mask plate 3 is placed below the effective mask area of the precision metal mask plate 4. The effective mask area of the precision metal mask plate 4 is distributed with pixel openings, and the pixel openings have small openings and large openings. The precision support sheet mask plate 3 is closely attached to one side of the large opening of the precision metal mask plate 4. The precision support sheet mask plate 3 cannot block the pixel openings of the precision metal mask plate 4 and cannot affect the evaporation effect of the precision metal mask plate 4. Therefore, the size of the opening of the precision metal mask plate 4 is larger than the large opening size of the pixel opening. The opening of the precision support sheet mask plate 3 can be an inverted trapezoid or other shaped openings, and the thickness of the precision support sheet mask plate 3 is 20 - 40um.

[0026] The opening of the precision support sheet mask plate 3 is an inverted trapezoid opening (wide at the top and narrow at the bottom), which can guide the evaporation material flow field to pass through the opening more evenly, reduce the accumulation of materials at the edge of the precision support sheet mask plate 3, and at the same time enhance the structural stiffness of the precision support sheet mask plate 3 by using the trapezoidal side walls.

[0027] The precision metal mask plate 4 is mainly used for the production of display screens, specifically for the production of pixel points (R, G, B) in the display screen. Therefore, at least three types of precision metal mask plates 4 are required for the production of pixel points in the display screen, and the pixel openings of each precision metal mask plate 4 respectively have the opening of pixel R, the opening of pixel B, and the opening of pixel G.

[0028] The shape of the opening of the precision support sheet mask plate 3 can be the shape of the pixel opening of its corresponding precision metal mask plate 4, such as the opening shape of pixel R, or the opening shape of pixel B, or the opening shape of pixel G. If the opening shape of the precision support sheet mask plate 3 is the detailed opening shape of its corresponding precision metal mask plate 4, the precision support sheet mask plate 3 can maintain its rigidity and improve the support strength for the precision metal mask plate 4.

[0029] The opening shape of the precision support sheet mask plate 3 can also be a composite shape that simultaneously includes the opening shapes of pixel R, pixel B, and pixel G. If the opening of the precision support sheet mask plate 3 simultaneously includes the opening shapes of pixel R, pixel B, and pixel G, it can adapt to multi-format mask multiplexing and improve the etching mass production efficiency of the precision support sheet mask plate 3.

[0030] The thickness of the precision support sheet mask plate 3 in the first region 31 is greater than the thickness of the second region 32, where the first region 31 refers to the region where the precision support sheet mask plate 3 overlaps with the mask frame 1, and the second region 32 refers to the region of the precision support sheet mask plate 3 within the mask frame 1. The thickness of the first region 31 is larger, and the larger thickness of the first region 31 can increase the support strength and tensile force of the precision support sheet mask plate 3 and enhance the tensile strength of the precision support sheet mask plate 3; the smaller thickness of the second region 32 makes the thickness of the region where the precision support sheet mask plate 3 overlaps with the precision metal mask plate 4 small, which can eliminate the influence of pixel shadows brought by the precision support sheet mask plate 3, and the small self-weight of the precision support sheet mask plate 3 can avoid the problem of excessive self-sagging and poor support effect on the FMM.

[0031] As Figure 2 shown, the precision metal mask plate 4 needs to be welded to the mask frame 1. At the overlapping position of the precision support sheet mask plate 3 and the precision metal mask plate 4 on the mask frame 1, a sunken concave platform 11 needs to be made on the mask frame 1. The depth of the concave platform 11 is equal to the thickness of the first region of the precision support sheet mask plate 3, so that after the precision support sheet mask plate 3 is welded to the mask frame 1, it is on the same surface as the surface of the mask frame, without affecting the welding of the precision metal mask plate.

[0032] The centers of gravity of the precision support sheet mask plate 3 and the precision metal mask plate 4 intersect. Since the effective mask area of the precision metal mask plate 4 has pixel openings, the center of gravity of the precision metal mask plate 4 is usually not at the center position of the FMM. Before welding the precision support sheet mask plate 3, use simulation software to simulate the precision metal mask plate 4 to find the center of gravity of the precision metal mask plate 4, so that the centers of gravity of the precision support sheet mask plate 3 and the precision metal mask plate 4 intersect.

[0033] As Figure 3As shown in the figure, the precision support sheet mask plate 3 is welded to the mask frame 1. The welding points of the precision support sheet mask plate 3 on the mask frame are the first welding points 33, where the size of the first welding points 33 is 200 - 500 um, and the spacing between the first welding points 33 is 1.5 - 2.5 mm; the precision metal mask plate 4 is welded to the mask frame 1, and the welding points of the precision metal mask plate 4 are the second welding points 41, where the size of the second welding points 41 is 200 - 400 um, and the spacing between the second welding points 41 is 1 - 2 mm.

[0034] Among them, the size of the first welding points 33 is larger than that of the second welding points 41. The first welding points 33 are at least two rows along the border of the mask frame 1, and the second welding points 41 are at least two rows along the border of the mask frame 1. The first welding points 33 and the second welding points 41 are arranged alternately.

[0035] The thickness of the precision support sheet mask plate 3 is large in the first area. The large size of the first welding points 33 reduces the requirement for welding precision, and the large size of the first welding points 33 can increase the welding contact area between the precision support sheet mask plate 3 and the mask frame 1, significantly improving the tensile strength of a single welding point and avoiding tearing or desoldering of the welding points.

[0036] The spacing between the first welding points 33 is 1.5 - 2.5 mm, which is designed in coordination with the size of the welding points to ensure that periodic high-strength fixed points are formed in the welding area between the precision support sheet mask plate 3 and the mask frame 1. The wide spacing can disperse the local stress concentration of the welding points. At least two rows of the first welding points 33 are arranged along the edge of the mask frame 1 to form multiple rows of tensile load paths to enhance the welding firmness.

[0037] The small size of the second welding points 41 allows precise micro spot welding to be used for the welding of the precision metal mask plate 4. While ensuring the fixing strength between the precision metal mask plate 4 and the mask frame 1, the size of the welding points is reduced and the spacing between the welding points is encrypted to reduce the interference of the heat generated by welding on the microscopic deformation of the precision metal mask plate 4. At least two rows of the second welding points 41 are arranged along the edge of the mask frame 1 to form multiple rows of tensile load paths to enhance the welding firmness.

[0038] The first welding points 33 and the second welding points 41 are arranged alternately on the mask frame 1. The staggered layout of the two types of welding points makes the load distribution on the mask frame 1 more uniform, reduces the internal stress caused by the difference in shrinkage rate between the precision support sheet mask plate 3 and the precision metal mask plate 4, and improves the overall tensile stability.

[0039] In another embodiment of the present application, a method for preparing a mask assembly is provided. A mask frame 1, a support sheet 2, a precision support sheet mask plate 3, and a precision metal mask plate 4 are provided, and the support sheet 2, the precision support sheet mask plate 3, and the precision metal mask plate 4 are welded to the mask frame 1 in sequence.

[0040] Before welding the support piece, apply a pre-pressure to the mask frame 1 on the outer periphery of the mask frame 1. The positions where the pressure is applied are the center points of each side of the mask frame 1 or 3 - 5 points evenly distributed. Apply a directional pre-pressure to the mask frame 1 before welding the support piece 2, so that when the frame rebounds naturally after welding, a reverse prestress is formed. This prestress can completely offset the inward tensile stress generated by the self-tension and self-gravity of the subsequent support piece 2, the precision support piece mask plate 3, and the precision metal mask plate 4 after installation, significantly improve the initial flatness of the mask assembly, and reduce the time-consuming of the leveling process before evaporation coating.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or equivalently replace some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A mask assembly, characterized in that, Comprising: A mask frame, a support sheet, a precision support sheet mask plate, and a precision metal mask plate arranged in sequence from bottom to top, wherein the support sheet is arranged on the mask frame and intersects with the precision metal mask plate at the invalid mask area of the precision metal mask plate, and the precision support sheet mask plate is arranged on the mask frame and penetrates through the effective mask area of the precision metal mask plate, wherein the opening of the precision support sheet mask plate in the effective mask area is larger than the opening of the precision metal mask plate.

2. The mask assembly according to claim 1, wherein: The opening shape of the precision support sheet mask plate is the same as the opening shape of the precision metal mask plate.

3. A mask assembly according to claim 1, wherein: The opening shape of the precision support sheet mask plate is a composite shape, and simultaneously includes the opening shapes of pixel R, pixel B, and pixel G.

4. A mask assembly according to claim 1, characterized in that The thickness of the precision support sheet mask plate in the first area is greater than the thickness in the second area.

5. A mask assembly according to claim 1, characterized in that: The centers of gravity of the precision support sheet mask plate and the precision metal mask plate intersect.

6. A mask assembly according to claim 1, wherein: The precision support sheet mask plate is welded to the mask frame, with the first solder joint size being 200 - 500um and the first solder joint pitch being 1.5 - 2.5mm.

7. A mask assembly according to claim 6, characterized in that: The precision metal mask plate is welded to the mask frame, with the second solder joint size being 200 - 400um and the second solder joint pitch being 1 - 2mm.

8. A mask assembly according to claim 7, characterized in that: The first solder joint size is larger than the second solder joint size, and the first solder joints and the second solder joints are arranged at intervals.

9. A method for preparing a mask assembly, which can be used to prepare the mask assembly according to any one of claims 1-8, characterized in that, Comprising: Providing a mask frame, a support sheet, a precision support sheet mask plate, and a precision metal mask plate, and sequentially welding the support sheet, the precision support sheet mask plate, and the precision metal mask plate to the mask frame.

10. The method for preparing a mask assembly according to claim 9, wherein Before welding the support sheet, apply a pre-pressure to the mask frame on the outer periphery of the mask frame.

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