Enhanced high-precision metal mask plate

Abstract

The invention relates to the field of OLED devices, and discloses an enhanced high-precision metal mask plate which comprises a mask plate, an evaporation area located in the middle of the mask plate, and non-evaporation areas located on the mask plate and close to the edges of the two sides. A plurality of micropore arrays are distributed in the evaporation area; a plurality of hexagonal opening units penetrating through the mask plate are formed in the non-evaporation area, a cooling channel is formed in each hexagonal opening unit, and a cooling medium is introduced into the cooling channels. The bionic honeycomb hollow structure is adopted in the non-evaporation area, so that the non-evaporation area achieves high rigidity while achieving light weight and weight reduction by 80%. The formed independent opening units can isolate long-range transmission of thermal stress, and integral buckling deformation is structurally avoided. And meanwhile, the cooling channel is introduced into the tapping unit, and the overall temperature of the mask plate is regulated and controlled through an external PID temperature control system, so that the problem of thermal creep is radically eradicated.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of OLED devices, in particular to an enhanced high-precision metal mask plate. BACKGROUND

[0002] With the gradual development of AMOLED display technology towards large size and high resolution, G8.6 generation line has become the highland of global panel manufacturers, and under this background, the metal mask plate as the key of evaporation process directly determines the imaging quality, resolution and production yield of OLED panel, etc. According to the functional differences of the metal mask plate, it is mainly divided into the following three categories: 1. General metal mask plate (CMM): responsible for the deposition of common layer materials such as HTL / HIL / ETL, controlling the uniformity of panel electrical performance. 2. Encapsulation metal mask plate (CVD Mask): accurately limits the area of the encapsulation layer in chemical vapor deposition, affecting the panel air tightness and folding life. 3. High-precision metal mask plate (FMM): realizes micron-level pixel deposition of RGB organic light-emitting materials, directly related to resolution and color purity, and its opening precision needs to be controlled within ±2.5μm, which is the key point of AMOLED manufacturing. Although the recent localization process has made a milestone breakthrough, but facing the technical needs of 8K display, foldable screen and other technologies in the future, the existing metal mask plate still has significant bottlenecks in large size deformation control, micro-hole precision stability and material utilization rate, etc.

[0003] In the horizontal evaporation process, due to the excessive size of G8.6 generation FMM, a certain amount of offset will be generated in the middle and edge of FMM, and the offset will be more obvious with the increase of FMM size, and the problem of gravity sagging not only is not conducive to improving the pixel density (PPI) of OLED, but also will reduce the color mixing yield, and thus greatly increase the production cost. In addition, due to the temperature fluctuation of the evaporation process cavity and the CTE mismatch of Invar alloy, the cumulative error of thermal expansion is caused, and the existing mask plate lacks active thermal deformation compensation mechanism.

[0004] It can be seen that the prior art still needs to be improved and improved. SUMMARY

[0005] In view of the shortcomings of the prior art, the purpose of the present application is to provide an enhanced high-precision metal mask plate, which aims to solve the problem of insufficient deformation resistance caused by the lack of gravity sagging and thermal stress compensation of the existing metal mask plate.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions: The application discloses an enhanced high-precision metal mask plate, which comprises a mask plate, an evaporation area located in the middle of the mask plate, and non-evaporation areas located close to the two side edges of the mask plate; a plurality of micro-hole arrays are arranged in the evaporation area; a plurality of hexagonal opening units penetrating through the mask plate are arranged in the non-evaporation areas, and a cooling channel is arranged in the interior of each hexagonal opening unit for passing in a cooling medium.

[0007] The enhanced high-precision metal mask plate, wherein the edges of each hexagonal opening unit are in contact with each other, and each hexagonal opening unit shares the same edges with the hexagonal opening units arranged around it.

[0008] The enhanced high-precision metal mask plate, wherein the wall thickness of each hexagonal opening unit is 40-60 mu m.

[0009] The enhanced high-precision metal mask plate, wherein the length of each edge of each hexagonal opening unit is 2-4 mm.

[0010] The enhanced high-precision metal mask plate, wherein a reinforcing plate is arranged in the hole wall of each hexagonal opening unit, and the extension direction of the reinforcing plate is parallel to the short edges located on the two sides of the mask plate.

[0011] The enhanced high-precision metal mask plate, wherein the thickness of the reinforcing plate is 0.3-0.5 mm.

[0012] The enhanced high-precision metal mask plate, wherein the cooling channel covers the hole wall surface of the hexagonal opening unit in a serpentine shape.

[0013] The enhanced high-precision metal mask plate, wherein the cooling channel is an oxygen-free copper cooling channel, the hexagonal opening unit is an invar alloy hexagonal opening unit, and the oxygen-free copper cooling channel and the invar alloy hexagonal opening unit are integrally formed by using a high-precision laser selective melting technology.

[0014] The enhanced high-precision metal mask plate, wherein the aperture of the micro-holes in the plurality of micro-hole arrays is 5-20 mu m.

[0015] The enhanced high-precision metal mask plate, wherein the evaporation area is an invar alloy evaporation area.

[0016] Beneficial effects: The application discloses an enhanced high-precision metal mask plate, which has the following advantages: 1. Lightweight: By using enhanced bionic honeycomb structure in the non-evaporation area, the structural rigidity of the bionic honeycomb is further improved by adding reinforcing plates in the hexagonal opening unit, so that the non-evaporation area realizes lightweight and weight reduction of 80% while achieving high rigidity.

[0017] 2. Improved sag resistance: The bionic honeycomb structure is not simply a solid material. It can efficiently convert the bending stress acting on the mask plate into axial tensile and compressive stress of the honeycomb wall in the form of hollowing. The material bears the load in its strongest axial direction, thus showing an equivalent elastic modulus far exceeding that of solid materials in macroscopic view.

[0018] 3. Structural innovation: The addition of enhanced honeycomb structure in the non-evaporation area forms multiple independent opening units that can isolate long-range transmission of thermal stress. The continuous and huge thermal stress on the entire mask plate is divided and scattered into countless local stresses confined in a single opening unit, thus avoiding overall warping deformation.

[0019] 4. Thermal deformation suppression: By introducing a serpentine cooling channel in the opening unit and passing -10℃ ethylene glycol solution through the cooling channel, the overall temperature of the mask plate is controlled by an external PID temperature control system, and the working temperature of the mask plate surface is controlled below 100℃, thus eliminating the occurrence of thermal creep problem from the root. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of an enhanced high-precision metal mask plate.

[0021] Figure 2 It is a structural schematic diagram of multiple hexagonal opening units.

[0022] Figure 3 It is a structural schematic diagram of a single hexagonal opening unit.

[0023] Figure 4 It is a schematic diagram of the gravity sag amount of the comparative example 1 mask plate.

[0024] Figure 5 It is a schematic diagram of the gravity sag amount of the enhanced high-precision metal mask plate of example 1.

[0025] Main component symbol explanation: 10-evaporation area, 20-non-evaporation area; 1-micropore array, 2-hexagonal opening unit, 3-reinforcing plate, 4-cooling channel. DETAILED DESCRIPTION

[0026] The application provides an enhanced high-precision metal mask plate, in order to make the purpose, technical scheme and effect of the application more clear and explicit, the application is further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the application and do not limit the protection scope of the application.

[0027] Please refer to Figures 1-3 The application provides an enhanced high-precision metal mask plate, comprising a mask plate, an evaporation area 10 located in the middle of the mask plate, and a non-evaporation area 20 located near the two side edges of the mask plate; a plurality of micro-hole arrays 1 are arranged in the evaporation area 10; a plurality of hexagonal opening units 2 penetrating through the mask plate are provided in the non-evaporation area 20, and a cooling channel 4 is arranged in the interior of each hexagonal opening unit 2, and the cooling channel 4 is used for introducing a cooling medium.

[0028] The above-mentioned enhanced high-precision metal mask plate adopts functional partitioning in structure, and divides the mask plate into an evaporation area 10 and a non-evaporation area 20.

[0029] The evaporation area 10 is the core area of the mask plate, directly performs the pixel pattern forming task of the organic light-emitting material (RGB) on the glass substrate, and is arranged with a plurality of high-precision micro-hole arrays 1 matched with the OLED pixel arrangement, wherein the aperture, pitch and shape precision of the micro-holes in the micro-hole array 1 directly determine the resolution, brightness uniformity and color purity of the final display panel.

[0030] The non-evaporation area 20 is the support and reinforcement area of the mask plate, does not participate in the evaporation and film forming process, and mainly provides stable support for the evaporation area 10, resists gravity sagging and thermal stress, and is the key reinforcement framework area for improving the overall rigidity of the mask plate. The area integrates a bionic honeycomb structure, adopts a regular hexagonal close-packed grid as a basic structural unit, and the bionic honeycomb structure composed of a plurality of hexagonal opening units 2 can bear the maximum load under the premise of using the least material, and realizes the balance between light weight and high rigidity.

[0031] Moreover, the bionic honeycomb structure composed of a plurality of hexagonal opening units 2 can efficiently convert the bending stress generated by the gravity and the tension force acting on the mask plate surface into the axial tensile stress of the plurality of hexagonal opening units 2. Furthermore, the plurality of independent hexagonal opening units 2 can thermodynamically isolate the long-distance transmission of thermal stress, and divide the continuous and huge thermal stress on the whole mask plate into a large number of local small stresses limited in the hexagonal opening units 2, thereby avoiding the overall warping deformation of the mask plate. Specifically, the honeycomb structure in the non-evaporation area 20 is made of an ultrathin Invar alloy strip, and the ultrathin strip with a thickness of less than 50 μm can be selected from domestic substitute materials (such as Baosteel Fe-36Ni strip). On the premise of ensuring the uniformity of the wall thickness (error ≤ ± 2 μm), the dependence on Japanese DNP strip is reduced, and the cost is controlled. The axial tensile strength of Invar alloy is about 500 MPa, and the bending strength is about 350 MPa. Therefore, the carrying capacity of Invar alloy material in the axial direction is much higher than that in the bending direction, so that the equivalent elastic modulus of the bionic honeycomb structure is 2-3 times higher than that of the traditional solid non-evaporation area with the same material and weight. While achieving a weight reduction of 80% (the hollowed-out area accounts for 80% of the area of the non-evaporation area 20, and the traditional solid structure has a hollowing rate of 0%), the anti-sagging capacity is greatly improved.

[0032] Meanwhile, the non-evaporation area 20 also integrates a micro-channel temperature control system to inhibit the occurrence of thermal deformation of the mask plate and solve the problem of lack of thermal stress compensation of the traditional mask plate. Specifically, the cooling medium is selected to be a 40% ethylene glycol aqueous solution, which has an ice point as low as -23°C, so as to avoid icing and blockage of the cooling channel 4 in a low-temperature environment. At the same time, the specific heat capacity of the solution is high, and the heat dissipation efficiency is excellent. The working temperature of the mask plate can be stably controlled below 100°C (the temperature of the traditional mask plate during evaporation can reach 120-130°C) through an external PID temperature control system, so as to fundamentally eliminate the micro-lattice slip of Invar alloy under the action of high temperature (> 120°C) and tension, which leads to irreversible plastic deformation, i.e. thermal creep. The occurrence of thermal creep will cause the mask plate to gradually relax and permanently lose precision, thereby ensuring that the micro-pore position precision error of the mask plate is small after long-term use.

[0033] Please refer to Figure 1 and Figure 2In some embodiments, the edges of each of the hexagonal opening units 2 are in contact with each other, and each of the hexagonal opening units 2 shares the same edges with the hexagonal opening units 2 surrounding it. The above-mentioned limitation forms a non-evaporation area 20 into a gapless, continuous, and thin-walled bionic honeycomb framework network, which can efficiently convert the bending stress generated by gravity and tension into axial tensile and compressive stress of the honeycomb wall, while achieving the maximum weight reduction of the non-evaporation area 20, improving the overall support stiffness, effectively solving the problem of gravity sagging of the G8.6 generation mask due to its oversized size, and ensuring the OLED pixel density (PPI) and color mixing yield. In addition, the continuous honeycomb network divides the non-evaporation area 20 into countless independent micro-units, which can fragment the continuous thermal stress generated by the temperature fluctuation of the evaporation cavity into local stress, avoiding the overall warping caused by long-distance transmission of thermal stress.

[0034] Please refer to Figure 2 In some embodiments, the wall thickness of each of the hexagonal opening units 2 is 40-60 μm. The wall thickness in the above-mentioned range can provide sufficient axial bearing capacity for the hexagonal opening unit 2, and in combination with the close-packed structure of regular hexagons, it can efficiently convert the bending stress acting on the mask into axial tensile and compressive stress of the hole wall, avoiding pixel deviation and color mixing yield reduction caused by insufficient support, while the wall thickness range will not affect the weight reduction effect of the mask as a whole, which is consistent with the concept of balancing the light weight and high stiffness of the non-evaporation area 20. In addition, the wall thickness range facilitates high-precision processing through laser cutting, molding and other processes.

[0035] Please refer to Figure 2 In some embodiments, the edge length of each of the hexagonal opening units 2 is 2-4 mm. The edge length range and the wall thickness range of the hexagonal opening unit 2 form a reasonable ratio, which can balance the demand for support strength and lightweight while ensuring the high specific stiffness characteristics of the bionic honeycomb structure. In addition, the above-mentioned edge length range can make the honeycomb unit form a thermally isolated micro-zone with appropriate size, which, in combination with the cooling channel 4, can limit the thermal stress during evaporation within a single unit, preventing overall warping caused by long-distance transmission of thermal stress, while the edge length range can ensure that the cooling medium can quickly absorb the heat of each unit, stabilizing the working temperature of the mask below 100°C, and preventing thermal creep of the invar alloy. Furthermore, the edge length range does not require ultra-precision equipment for high-precision cutting and molding, avoiding the dramatic increase in processing difficulty caused by too small edge length, or the decrease in structural stability caused by too large edge length.

[0036] Please refer to Figure 2 and Figure 3In some embodiments, a reinforcing plate 3 is arranged in the hole wall of each hexagonal opening unit 2, and the extending direction of the reinforcing plate 3 is parallel to the short side of the mask plate on both sides. The arrangement of the reinforcing plate 3 can make up for the short board of the hexagonal opening unit 2 in terms of buckling resistance when the hole wall is only supported, especially when the G8.6 generation mask plate with a large size bears the gravity and tension, which can effectively prevent the deformation or buckling of the hole wall due to local stress concentration, and avoid the deviation of the micro-pore array 1 in the evaporation area 10 due to structural deformation. The extending direction of the reinforcing plate 3 parallel to the short side of the mask plate can cope with the bending stress that is easy to occur in the long side direction (i.e. outward tension) of the mask plate during horizontal evaporation, and the gravity acting on the long side of the large-size mask plate is more significant. Through directional reinforcement, the anti-deformation ability in the long side direction is improved, and the problem that the deviation of the middle and edge of the traditional mask plate increases with the size is solved. Specifically, the reinforcing plate 3 can be made of the same invar alloy material as the hexagonal opening unit 2, and is integrally formed with the hole wall and the cooling channel 4 through high-precision selective laser melting technology (SLM), so as to realize the synergistic optimization of structural strength, thermal stability and process feasibility.

[0037] Please refer to Figure 3 In some embodiments, the thickness of the reinforcing plate 3 is 0.3-0.5 mm. The above thickness range can make up for the short board of the hexagonal opening unit 2 in terms of buckling resistance, and the 0.3-0.5 mm reinforcing plate 3 can significantly improve the anti-deformation ability of the hole wall when the G8.6 generation mask plate bears the gravity and tension, and in combination with the extending direction parallel to the short side of the mask plate, it can resist the bending stress of the mask plate in the long side direction. At the same time, the thickness will not increase the overall weight of the mask plate due to excessive material, which will affect the overall weight reduction effect of the mask plate. Specifically, the thickness of the reinforcing plate 3 is greater than the thickness of the side length of the hexagonal opening unit 2. The honeycomb structure composed of the hexagonal opening unit 2 is mainly used to realize the lightweight of the non-evaporation area 20 while building the basic support skeleton. The too thick side length will reduce the weight reduction effect of the non-evaporation area 20, and the too thin side length will not form a stable skeleton; and the main role of the reinforcing plate 3 is to directionally reinforce the buckling resistance. The mask plate is easy to produce bending stress in the long side direction during horizontal evaporation due to the size being too large, which causes the middle to sag. The reinforcing plate 3 needs to provide stronger structural rigidity through greater thickness to make up for the short board of the thin wall of the hexagonal opening unit 2 in terms of local buckling resistance and stress concentration, and to ensure that the deformation caused by gravity and tension can be resisted.

[0038] Please refer to Figure 3 In some embodiments, the cooling channel 4 covers the hole wall surface of the hexagonal opening unit 2 in a serpentine shape. The serpentine shape of the cooling channel 4 can maximize the coverage of the hole wall surface of the hexagonal opening unit 2, so that the cooling medium in the cooling channel 4 can uniformly absorb the heat of each opening unit.

[0039] In some embodiments, the cooling channel 4 is an oxygen-free copper cooling channel, and the hexagonal opening unit 2 is an Invar hexagonal opening unit. The oxygen-free copper cooling channel and the Invar hexagonal opening unit are integrally formed by using a high-precision laser selective melting technology. Oxygen-free copper has a very high thermal conductivity, which is more than 10 times that of Invar. As the material of the cooling channel 4, oxygen-free copper can quickly absorb the heat generated by the Invar hexagonal opening unit 2 during the evaporation process. In combination with the serpentine cooling channel 4, the heat can be efficiently transferred to the cooling medium, effectively solving the problem of accumulated error caused by thermal expansion due to temperature fluctuation of the evaporation chamber. The integrally formed by the high-precision laser selective melting technology avoids the interface thermal resistance generated by the traditional welding process, so that the oxygen-free copper channel and the Invar opening unit form a tightly connected whole structure, which not only eliminates the heat transfer loss caused by the interface gap, but also avoids the local deformation caused by welding stress, further improving the stability and fatigue resistance of the whole structure of the mask plate.

[0040] In some embodiments, the pore diameter of the micropore array 1 is 5-20 μm. The mask plate needs to meet the requirements of 4K / 8K high resolution and different generations of line panels. When 8K display is adapted, a pore diameter of 5-8 μm can be selected, and when 4K display is adapted, a pore diameter of 10-15 μm can be selected. This can accurately correspond to the pixel size requirements of the OLED panel, avoid pixel overlap caused by too large a pore diameter or insufficient brightness caused by too small a pore diameter, and directly ensure the resolution, brightness uniformity and color purity of the display panel. The pore diameter range of 5-20 μm is highly compatible with the high-precision laser etching process, which not only meets the accuracy requirements of 300PPI or more resolution of G8.6 generation line, but also avoids the sharp increase in processing difficulty caused by too small a pore diameter or the decrease in structural strength caused by too large a pore diameter.

[0041] In some embodiments, the evaporation area 10 is an Invar evaporation area. The evaporation area 10 as a whole is made of Invar (Fe-36Ni), which has a very low thermal expansion coefficient of about 1.2×10-6 / ℃ at 20℃. The evaporation area 10 made of the above material can significantly reduce the influence of temperature fluctuation of the evaporation chamber on the position accuracy of the micropores, and avoid the problems of pixel shift and color mixing caused by thermal expansion.

[0042] In order to further illustrate the enhanced high-precision metal mask plate provided by the present application, the following examples are provided.

[0043] Example 1 The application discloses an enhanced high-precision metal mask plate, which comprises a mask plate, an evaporation area made of inconel alloy arranged in the middle of the mask plate, and a non-evaporation area made of inconel alloy arranged near the edges of the mask plate; a plurality of micro-hole arrays are arranged in the evaporation area; a plurality of hexagonal opening units penetrating through the mask plate are arranged in the non-evaporation area, and a cooling channel in a snakelike shape covering the hole wall surface of each hexagonal opening unit is arranged in the interior of each hexagonal opening unit, and the cooling channel is used for introducing a cooling medium.

[0044] The diameter of each micro-hole array is 5 microns. The edges of each hexagonal opening unit are in abutment with each other, and each hexagonal opening unit shares the same edges with the hexagonal opening units arranged around the hexagonal opening unit. The wall thickness of each hexagonal opening unit is 50 microns, and the edge length is 4 mm. A reinforcing plate with a thickness of 0.4 mm is arranged in the hole wall of each hexagonal opening unit, and the extension direction of the reinforcing plate is parallel to the short edges of the mask plate on both sides. The cooling channel is an oxygen-free copper cooling channel, the hexagonal opening unit is an inconel alloy hexagonal opening unit, and the oxygen-free copper cooling channel and the inconel alloy hexagonal opening unit are integrally formed by using a high-precision laser selective melting technology.

[0045] Embodiment 2 The application discloses an enhanced high-precision metal mask plate, which comprises a mask plate, an evaporation area made of inconel alloy arranged in the middle of the mask plate, and a non-evaporation area made of inconel alloy arranged near the edges of the mask plate; a plurality of micro-hole arrays are arranged in the evaporation area; a plurality of hexagonal opening units penetrating through the mask plate are arranged in the non-evaporation area, and a cooling channel in a snakelike shape covering the hole wall surface of each hexagonal opening unit is arranged in the interior of each hexagonal opening unit, and the cooling channel is used for introducing a cooling medium.

[0046] The diameter of each micro-hole array is 10 microns. The edges of each hexagonal opening unit are in abutment with each other, and each hexagonal opening unit shares the same edges with the hexagonal opening units arranged around the hexagonal opening unit. The wall thickness of each hexagonal opening unit is 60 microns, and the edge length is 3 mm. A reinforcing plate with a thickness of 0.3 mm is arranged in the hole wall of each hexagonal opening unit, and the extension direction of the reinforcing plate is parallel to the short edges of the mask plate on both sides. The cooling channel is an oxygen-free copper cooling channel, the hexagonal opening unit is an inconel alloy hexagonal opening unit, and the oxygen-free copper cooling channel and the inconel alloy hexagonal opening unit are integrally formed by using a high-precision laser selective melting technology.

[0047] Embodiment 3 An enhanced high-precision metal mask includes a mask, a vapor deposition zone made of Invar alloy located in the middle of the mask, and a non-vapor deposition zone made of Invar alloy located near the two side edges of the mask; the vapor deposition zone is provided with a plurality of micropore arrays; the non-vapor deposition zone is provided with a plurality of hexagonal opening units penetrating the mask, and each hexagonal opening unit has a cooling channel that covers the hole wall surface of the hexagonal opening unit in a serpentine manner, and the cooling channel is used to introduce a cooling medium.

[0048] The micropore arrays each have a pore diameter of 15 μm. The edges of each hexagonal aperture unit are fitted together, and each hexagonal aperture unit shares the same edge with the surrounding hexagonal aperture units. Each hexagonal aperture unit has a wall thickness of 40 μm and a side length of 2 mm. A 0.5 mm thick reinforcing plate is provided in the aperture wall of each hexagonal aperture unit, and the extension direction of the reinforcing plate is parallel to the short sides of the mask plate on both sides. The cooling channel is an oxygen-free copper cooling channel, and the hexagonal aperture units are Invar alloy hexagonal aperture units. High-precision laser selective melting technology is used to integrally form the oxygen-free copper cooling channel and the Invar alloy hexagonal aperture units.

[0049] Comparative Example 1 It is basically the same as Example 1, except that Comparative Example 1 does not have a non-evaporation zone.

[0050] Performance testing: from Figure 4 and Figure 5 The amount of sag of the mask plate due to its own weight under the tension of the mesh (the two short sides of the mask plate are subjected to outward tension) can be seen in Comparative Example 1 ( Figure 4 The maximum deformation under gravity is -0.82392 mm, Example 1 ( Figure 5 The maximum deformation value under gravity is -0.79968mm. Compared with the previous version, the deformation value under gravity of this enhanced FMM is reduced by about 25μm, which can improve the anti-sagging ability of the mask plate and achieve weight reduction while meeting the rigidity requirements.

[0051] In summary, the application adopts the enhanced bionic honeycomb hollow structure in the non-evaporation area, so that the non-evaporation area realizes lightweight and weight reduction of 80% while achieving high rigidity, can efficiently convert the bending stress acting on the mask plate into axial tensile and compressive stress of the honeycomb wall, and the material bears the load in the strongest axial direction, thereby showing equivalent elastic modulus far exceeding that of solid materials in a macroscopic manner. In addition, the formed independent open cell unit can isolate the long-range transmission of thermal stress, and divide and scatter the continuous and huge thermal stress on the whole mask plate into numerous local stresses limited in a single open cell unit, thereby avoiding overall warping deformation in structure. Meanwhile, by introducing the serpentine cooling channel in the open cell unit, the overall temperature of the mask plate is controlled by the external PID temperature control system, and the working temperature of the mask plate surface is controlled below 100 DEG C, thereby eliminating the occurrence of thermal creep from the root.

[0052] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0053] In addition, the terms "first", "second", "third" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second", "third" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0054] In the description of the present application, it should be noted that, unless otherwise specifically defined and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the communication between two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0055] It can be understood that, for those ordinary skilled in the art, equivalent replacements or changes can be made according to the technical solutions and the inventive concept of the present application, and all the changes or replacements shall fall within the protection scope of the present application.

Claims

1. An enhanced high precision metal mask plate, characterized by, The mask plate comprises an evaporation area in the middle of the mask plate and non-evaporation areas near the edges of the mask plate; a plurality of micro-hole arrays are arranged in the evaporation area; a plurality of hexagonal opening units are arranged in the non-evaporation areas, and each hexagonal opening unit is provided with a cooling channel for passing cooling medium.

2. The enhanced high precision metal mask of claim 1, wherein, The edges of each hexagonal opening unit are in contact with each other, and each hexagonal opening unit shares the same edges with the hexagonal opening units arranged around it.

3. The enhanced high precision metal mask of claim 2, wherein, The wall thickness of each hexagonal opening unit is 40-60 μm.

4. The enhanced high precision metal mask of claim 2, wherein, The length of each hexagonal opening unit is 2-4 mm.

5. The enhanced high precision metal mask of claim 2, wherein, A reinforcing plate is arranged in the hole wall of each hexagonal opening unit, and the extension direction of the reinforcing plate is parallel to the short edges of the mask plate.

6. The enhanced high precision metal mask of claim 5, wherein, The thickness of the reinforcing plate is 0.3-0.5 mm.

7. The enhanced high precision metal mask of claim 1, wherein, The cooling channel covers the hole wall surface of the hexagonal opening unit in a serpentine shape.

8. The enhanced high precision metal mask of claim 7, wherein, The cooling channel is an oxygen-free copper cooling channel, and the hexagonal opening unit is an invar alloy hexagonal opening unit, and the oxygen-free copper cooling channel and the invar alloy hexagonal opening unit are integrally formed by using high-precision laser selective melting technology.

9. The enhanced high precision metal mask of claim 1, wherein, The diameter of the micro-holes in the plurality of micro-hole arrays is 5-20 μm.

10. The enhanced high precision metal mask of claim 1, wherein, The evaporation area is an invar alloy evaporation area.

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