Adjusting device for vapor deposition alignment bending amount of large-size substrate
By setting up a load bearing seat and weight reduction mechanism on the mask plate frame of the vapor deposition machine, the pressure contacting the back plate is buffered, and the deformation and fitting deviation caused by excessive pressure gravity is solved. The alignment and fitting accuracy of the glass substrate and the mask plate is improved, and the coating quality of the product is ensured.
Patent Information
- Application Number
- CN202311633370.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-01
- Publication Date
- 2025-03-11
AI Technical Summary
In the evaporation machine, excessive load load weight of the mask plate placed on the base leads to slight deformation, affecting the alignment and fitting accuracy of the glass substrate and the mask plate, resulting in coating deviation and poor color mixing of the product.
An adjustment device for a large-size substrate is designed, including a mask plate frame, a load bearing seat and a weight reduction mechanism. By setting a load seat around the mask plate frame and installing a weight reduction mechanism, including a buffer column, a limiting ring and a buffer spring, on the load seat, to buffer the pressure contacting the back plate, and reduce the pressure gravity under the base of the mask plate placement.
It effectively improves the alignment and bonding accuracy of the glass substrate and the mask plate, avoids deformation and bonding deviation caused by excessive pressure and gravity on the base placed on the mask plate, and ensures the coating quality of the product.
Smart Images
Figure CN119592905A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of vapor deposition machines, and in particular to a device for adjusting the bending amount of vapor deposition alignment of a large-size substrate. Background Art
[0002] The evaporation machine is a device used to produce OLED display screens. It mainly achieves coating through evaporation and physical vapor deposition. However, in order to ensure the coating quality of the product, the glass substrate and the mask need to be aligned and bonded before using the evaporation machine for coating, and the alignment and bonding accuracy of the glass substrate and the mask need to be ensured, especially the error value of the fine metal mask must be ≤3μm. The entire alignment system of the evaporation machine is composed of a mask placement base, a mask, a contact backplane, a glass substrate and a magnetic plate. The glass substrate is first placed on the mask, and the contact backplane is covered on top of the glass substrate. Finally, the magnetic plate is covered on the contact backplane to adsorb the mask, and the glass substrate is pressed tightly against the mask to fully fit the glass substrate and complete the alignment and bonding of the mask and the glass substrate.
[0003] However, this alignment and bonding method will cause the mask base to bear the weight of the mask, glass substrate, and the contact back plate pressed on the glass substrate, which may easily cause the mask base to be slightly deformed due to excessive load, and cause a gap between the deformed mask base and the mask, affecting the alignment and bonding accuracy of the glass substrate and the mask bonded to the mask base, thereby causing the pixel area on the glass substrate to shift and the coating to be offset, resulting in poor color mixing of the product, affecting the coating quality of the product. Therefore, those skilled in the art provide a device for adjusting the alignment bending amount of large-size substrate evaporation to solve the problems raised in the above background technology. Summary of the invention
[0004] The object of the present invention is to provide a device for adjusting the bending amount of large-size substrate evaporation alignment to solve the problems raised in the above-mentioned background technology.
[0005] To achieve the above object, the present invention provides the following technical solutions:
[0006] A device for adjusting the bending amount of evaporation alignment of a large-size substrate comprises: a mask placement base, a glass substrate, a contact back plate and a magnetic plate, a mask frame is arranged at the middle position of the top of the mask placement base, the glass substrate, the contact back plate and the magnetic plate are arranged above the mask frame in sequence, and the glass substrate covers the mask on the mask frame, a plurality of bearing seats are evenly clamped and installed around the top of the mask frame, one end of the bearing seat extends to the bottom of the glass substrate, and a lifting plate is arranged at one end of the bearing seat located below the glass substrate, and the upper end surface of the lifting plate is attached to the lower end surface of the glass substrate The top of the bearing seat is located on one side of the glass substrate and is provided with a weight reduction mechanism below the contact back plate. The weight reduction mechanism includes a fixed cylinder, which is threadedly installed inside the bearing seat, and a buffer column is provided inside the fixed cylinder. The buffer column penetrates the fixed cylinder in a movable manner and extends above it, and a limiting ring is provided on the portion of the outer wall of the buffer column located inside the fixed cylinder, and a buffer spring is provided around the outside of the buffer column on the lower end surface of the limiting ring, and the other end of the buffer spring is installed on the inner wall of the fixed cylinder, and a contact plate is provided at one end of the buffer column located above the fixed cylinder, and the contact plate is attached to the lower end surface of the contact back plate.
[0007] Preferably, a plurality of slots are evenly formed around the top of the mask frame, the bearing seat is snap-fitted and installed inside the slots, and the height of the bearing seat is smaller than the depth of the slots.
[0008] Preferably, a groove is provided at one end of the top of the supporting seat located below the glass substrate, and the lifting plate is mounted on the top of the supporting seat by snapping into the groove. In addition, a fastening bolt is provided on the top of the lifting plate located on one side of the glass substrate, and the fastening bolt passes through the lifting plate and is threadedly installed inside the supporting seat, and the upper end surface of the lifting plate is flush with the upper end surface of the mask frame.
[0009] Preferably, the outer wall of the fixing tube is provided with a thread ring, the top of the bearing seat is provided with a thread groove on one side of the glass substrate, and the fixing tube is installed inside the bearing seat through the matching threads of the thread ring and the thread groove.
[0010] Preferably, a cavity for sliding of a limiting ring is opened inside the fixing cylinder, the buffer column is slidably installed inside the cavity through the limiting ring, and the end surface area of the limiting ring is larger than the opening area of the cavity.
[0011] Preferably, a buffer pad is provided on the upper end surface of the contact plate, and the contact plate is attached to the lower end surface of the contact back plate through the buffer pad, and the materials of the lifting plate and the buffer pad are both rubber.
[0012] Preferably, a top plate for limiting the position of the fixing tube is provided on the top of the fixing tube, and the top plate is attached to the upper end surface of the supporting seat, the sum of the heights of the top plate and the contact plate is the same as the distance from the upper end surface of the supporting seat to the upper end surface of the glass substrate, and the upper end surface of the contact plate is flush with the upper end surface of the glass substrate.
[0013] Preferably, one end of the supporting seat away from the glass substrate passes through the mask frame and extends to the outside thereof, and a lifting frame is arranged inside the evaporator around the outside of the mask frame, and an extension bolt is arranged at one end of the top of several supporting seats located outside the mask frame, and the extension bolt passes through the lifting frame and is threadedly installed inside the supporting seat.
[0014] Compared with the prior art, the advantages of the present invention are:
[0015] By arranging bearing seats around the mask frame and arranging a weight-reducing mechanism on the bearing seats, when the glass substrate and the mask are aligned and bonded, the magnetic plate can be pressed on the top of the glass substrate through the contact back plate, and the magnetic plate can adsorb the mask on the mask frame, and the glass substrate can be pressed tightly on the mask on the mask frame, so that the glass substrate and the mask are fully bonded. At the same time, in the process of the contact back plate moving downward to press the glass substrate, the contact back plate can be contacted with the contact plate, and the contact plate can be pressed to move downward, so that the buffer column installed at the bottom of the contact plate moves into the fixed cylinder, and then the buffer column drives the limit ring installed on its outer wall to move in the air. The buffer spring slides downward in the cavity and compresses the buffer spring, which can buffer the downward pressure of the contact back plate through the elastic force of the buffer spring, and allows the buffer column to provide a certain supporting force to the contact back plate under the action of the buffer spring, offsetting part of the weight of the contact back plate and the magnetic plate, reducing the compressive force on the mask placement base, avoiding the deviation in the alignment and bonding of the mask plate and the glass substrate due to deformation of the mask placement base due to excessive compressive force, resulting in offset of the pixel area on the glass substrate and poor color mixing on the product surface, thereby improving the alignment and bonding accuracy of the mask plate and the glass substrate and ensuring the coating quality of the product. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 is a three-dimensional schematic diagram of an adjusting device according to an embodiment of the present invention;
[0017] Figure 2 It is a schematic diagram of disassembling a glass substrate, a contact back plate, a magnetic plate and a mask frame according to an embodiment of the present invention;
[0018] Figure 3 is a schematic diagram of a use state of a weight reduction mechanism according to an embodiment of the present invention;
[0019] Figure 4 is a schematic diagram of the assembly of a weight reduction mechanism according to an embodiment of the present invention;
[0020] Figure 5 It is a schematic diagram of the disassembly of the fixing cylinder, the lifting plate and the bearing seat according to an embodiment of the present invention;
[0021] Figure 6 is a cross-sectional view of a weight reduction mechanism according to an embodiment of the present invention;
[0022] Figure 7 is a three-dimensional schematic diagram of a fixing cylinder according to an embodiment of the present invention;
[0023] Figure 8 FIG. 4 is a schematic three-dimensional diagram of a buffer column according to an embodiment of the present invention.
[0024] In the figure: 1. mask placement base; 2. mask frame; 201. slot; 21. bearing seat; 211. groove; 212. threaded groove; 22. lifting plate; 23. extension bolt; 24. fastening bolt; 3. glass substrate; 4. contact back plate; 5. magnetic plate; 6. weight reduction mechanism; 61. fixing cylinder; 611. cavity; 612. threaded ring; 62. top plate; 63. buffer column; 64. limiting ring; 65. buffer spring; 66. contact plate; 661. buffer pad. DETAILED DESCRIPTION
[0025] In the description of the present invention, it should be understood that the terms "center", "lateral", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In addition, the term "including" and any variation thereof are intended to cover non-exclusive inclusions.
[0026] Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5As shown, a mask plate is placed on a base 1, a glass substrate 3, a contact back plate 4 and a magnetic plate 5. A mask plate frame 2 is arranged in the middle position of the top of the mask plate placement base 1. The glass substrate 3, the contact back plate 4 and the magnetic plate 5 are arranged on the top of the mask plate frame 2 in sequence, and the glass substrate 3 covers the top of the mask on the mask plate frame 2. A plurality of card slots 201 are evenly opened around the top of the mask plate frame 2. A bearing seat 21 is snap-fitted and installed in the inside of the card slot 201. One end of the bearing seat 21 extends to the bottom of the glass substrate 3. A groove 211 is opened at the end of the top of the bearing seat 21 located below the glass substrate 3. A lifting plate 22 is snap-fitted and installed on the top of the bearing seat 21 through the groove 211. The lifting plate 22 The upper end surface is attached to the lower end surface of the glass substrate 3, and the height of the supporting seat 21 is less than the depth of the slot 201. The top of the lifting plate 22 is located on one side of the glass substrate 3 and is provided with a fastening bolt 24. The fastening bolt 24 passes through the lifting plate 22 and is threadedly installed inside the supporting seat 21. The upper end surface of the lifting plate 22 is flush with the upper end surface of the mask frame 2. One end of the supporting seat 21 away from the glass substrate 3 passes through the mask frame 2 and extends to the outside. In addition, a lifting frame is provided inside the evaporator around the outside of the mask frame 2. An extension bolt 23 is provided at one end of the top of several supporting seats 21 located outside the mask frame 2. The extension bolt 23 passes through the lifting frame and is threadedly installed inside the supporting seat 21.
[0027] In one embodiment, when the mask and the glass substrate 3 are aligned and bonded, the glass substrate 3 is first placed on a bearing seat 21 fixed to the bottom of the lifting frame by an extension bolt 23, and then the position of the lifting frame is adjusted to allow the lifting frame to move downward, and the bearing seat 21 is snap-fitted and installed in the card slot 201, so that the glass substrate 3 covers the mask of the mask frame 2, and then the contact back plate 4 and the magnetic plate 5 are sequentially covered on the top of the glass substrate 3, so that the magnetic plate 5 is pressed on the top of the glass substrate 3 through the contact back plate 4, and the magnetic plate 5 is adsorbed on the mask on the mask frame 2, and the glass substrate 3 is pressed tightly against the mask on the mask frame 2, so that the glass substrate 3 and the mask are fully bonded, thereby completing the alignment and bonding of the mask and the glass substrate 3, and realizing the limitation of the glass substrate 3.
[0028] In one embodiment, when the glass substrate 3 is covered on the mask, the glass substrate 3 can be attached to the upper end surface of the lifting plate 22, and the lifting plate 22 made of rubber material is in contact with the glass substrate 3, thereby avoiding scratches on the surface of the glass substrate 3 caused by direct contact between the surface of the glass substrate 3 and the supporting seat 21, thereby protecting the glass substrate 3. Moreover, after long-term use, the fastening bolts 24 can be screwed to remove the lifting plate 22 for replacement, which has a simple structure and convenient operation, and is conducive to the subsequent maintenance work.
[0029] Combination Figure 1, Figure 3 , Figure 4 and Figure 6 As shown, a weight reduction mechanism 6 is provided at the top of the bearing seat 21, which is located on one side of the glass substrate 3 and below the contact back plate 4. The weight reduction mechanism 6 includes a fixed cylinder 61. A cavity 611 for sliding of a limiting ring 64 is provided inside the fixed cylinder 61. A buffer column 63 is slidably installed inside the cavity 611 through the limiting ring 64. In addition, one end of the buffer column 63 passes through the fixed cylinder 61 and extends above it. A limiting ring 64 is provided on the portion of the outer wall of the buffer column 63 located inside the fixed cylinder 61. A buffer spring 65 is provided around the outside of the buffer column 63 on the lower end surface of the limiting ring 64. The other end of the buffer spring 65 is installed on the inner wall of the fixed cylinder 61. A contact plate 66 is provided at one end of the buffer column 63 located above the fixed cylinder 61. The contact plate 66 is attached to the lower end surface of the contact back plate 4, and a buffer pad 661 is provided on the upper end surface of the contact plate 66. The contact plate 66 is attached to the lower end surface of the contact back plate 4 through the buffer pad 661. The material of the buffer pad 661 is rubber.
[0030] In one embodiment, when the magnetic plate 5 and the contact back plate 4 press the glass substrate 3, the contact back plate 4 can be brought into contact with the contact plate 66 during the downward movement, and the contact plate 66 can be pressed to move downward, so that the buffer column 63 installed at the bottom of the contact plate 66 can move into the fixed tube 61, and then the buffer column 63 drives the limit ring 64 installed on its outer wall to slide downward in the cavity 611 and press the buffer spring 65 to deform, so that the downward pressure of the contact back plate 4 can be buffered by the elastic force of the buffer spring 65, and the buffer column 63 can be moved downward. Under the action of the elastic force of the buffer spring 65, a certain supporting force is provided to the contact back plate 4, offsetting part of the weight of the contact back plate 4 and the magnetic plate 5, reducing the compressive force on the mask plate placement base 1, and avoiding the deviation in the alignment and bonding of the mask plate and the glass substrate 3 due to deformation of the mask plate placement base 1 due to excessive compressive force, resulting in offset of the pixel area on the glass substrate 3 and displacement of the coating, resulting in poor color mixing on the product surface, thereby improving the alignment and bonding accuracy of the mask plate and the glass substrate 3 and ensuring the coating quality of the product.
[0031] In one embodiment, when the weight reduction mechanism 6 is used, the contact plate 66 can be allowed to contact the contact back plate 4 through a rubber buffer pad 661 to prevent the contact back plate 4 from directly colliding with the contact plate 66, thereby avoiding the occurrence of scratches on the contact back plate 4 due to the direct collision between the contact back plate 4 and the contact plate 66, thereby protecting the contact back plate 4.
[0032] Combination Figure 4 , Figure 5 , Figure 7 and Figure 8As shown, the outer wall of the fixing cylinder 61 is provided with a thread ring 612, and the top of the bearing seat 21 is located on one side of the glass substrate 3 and is provided with a thread groove 212. The fixing cylinder 61 is installed inside the bearing seat 21 through the matching threads of the thread ring 612 and the thread groove 212. A top plate 62 for limiting the position of the fixing cylinder 61 is provided on the top of the fixing cylinder 61, and the top plate 62 is attached to the upper end surface of the bearing seat 21. The sum of the heights of the top plate 62 and the contact plate 66 is the same as the distance from the upper end surface of the bearing seat 21 to the upper end surface of the glass substrate 3, and the upper end surface of the contact plate 66 is flush with the upper end surface of the glass substrate 3.
[0033] In one embodiment, when installing the weight reduction mechanism 6, the fixing tube 61 can be installed inside the bearing seat 21 by cooperating with the thread ring 612 and the thread groove 212, so that the top plate 62 is fitted on the top of the bearing seat 21 to limit the fixing tube 61, which can prevent the fixing tube 61 from extending to the inside of the thread groove 212 and being unable to be removed, thereby facilitating the disassembly and assembly of the fixing tube 61. Moreover, the fixing tube 61 can be directly twisted to disassemble and assemble the weight reduction mechanism 6. The structure is simple and the disassembly is convenient, which facilitates the subsequent maintenance work.
[0034] In one embodiment, when the weight reduction mechanism 6 is not in use, since the end face area of the limiting ring 64 is larger than the opening area of the cavity 611, the limiting ring 64 can be limited by the fixed tube 61 to prevent the buffer column 63 from moving upward and separating from the fixed tube 61 through the limiting ring 64 in the cavity 611 under the influence of the elastic force of the buffer spring 65, thereby achieving the limitation of the buffer column 63 and ensuring the use of the weight reduction mechanism 6.
[0035] The working principle of the present invention is: when the glass substrate 3 and the mask are aligned and bonded, the glass substrate 3 is first placed on the bearing seat 21 fixed to the bottom of the lifting frame by the lengthened bolts 23, and then the position of the lifting frame is adjusted to allow the lifting frame to move downward, and the bearing seat 21 is snap-fitted and installed in the card slot 201, so that the glass substrate 3 covers the mask of the mask frame 2, and then the contact back plate 4 and the magnetic plate 5 are sequentially covered on the top of the glass substrate 3, and the magnetic plate 5 is pressed on the top of the glass substrate 3 through the contact back plate 4, and the magnetic plate 5 is adsorbed on the mask on the mask frame 2, and the glass substrate 3 is pressed tightly on the mask on the mask frame 2, so that the glass substrate 3 and the mask are fully bonded, and at the same time, the contact back plate 4 contacts with the contact plate 66 during the downward movement, and presses the contact plate 66 to move downward, so that the magnetic plate 5 installed on the bottom of the contact plate 66 The buffer column 63 at the top is displaced into the fixed cylinder 61, and then the buffer column 63 drives the limiting ring 64 installed on its outer wall to slide downward in the cavity 611 and press the buffer spring 65 to deform, so that the downward pressure of the contact back plate 4 can be buffered by the elastic force of the buffer spring 65, and the buffer column 63 provides a certain supporting force to the contact back plate 4 under the action of the elastic force of the buffer spring 65, offsetting part of the weight of the contact back plate 4 and the magnetic plate 5, thereby reducing the compressive force on the mask plate placing base 1, avoiding the deviation of the alignment and bonding of the mask plate and the glass substrate 3 due to the deformation of the mask plate placing base 1 under excessive compressive force, resulting in the deviation of the pixel area on the glass substrate 3 and the coating displacement causing poor color mixing on the product surface, thereby improving the alignment and bonding accuracy of the mask plate and the glass substrate 3 and ensuring the coating quality of the product.
[0036] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A device for adjusting the bending amount of large-size substrate evaporation, comprising: A mask plate placement base (1), a glass substrate (3), a contact back plate (4) and a magnetic plate (5), characterized in that a mask plate frame (2) is arranged at the middle position of the top of the mask plate placement base (1), the glass substrate (3), the contact back plate (4) and the magnetic plate (5) are arranged in sequence above the mask plate frame (2), and the glass substrate (3) covers the top of the mask plate on the mask plate frame (2), and a plurality of bearing seats (21) are evenly mounted on the top of the mask plate frame (2), one end of the bearing seat (21) extends to the bottom of the glass substrate (3), and a lifting plate (22) is arranged at the end of the bearing seat (21) located below the glass substrate (3), the upper end surface of the lifting plate (22) is attached to the lower end surface of the glass substrate (3), and the top of the bearing seat (21) is located on one side of the glass substrate (3) and is positioned A weight reduction mechanism (6) is provided below the contact back plate (4), and the weight reduction mechanism (6) comprises a fixed tube (61), and the fixed tube (61) is threadedly mounted inside the bearing seat (21), and a buffer column (63) is provided inside the fixed tube (61), and the buffer column (63) penetrates the fixed tube (61) in a movable manner and extends to the top thereof, and a limiting ring (64) is provided on the outer wall of the buffer column (63) located inside the fixed tube (61), and a buffer spring (65) is provided on the lower end surface of the limiting ring (64) around the outside of the buffer column (63), and the other end of the buffer spring (65) is mounted on the inner wall of the fixed tube (61), and a contact plate (66) is provided on the end of the buffer column (63) located above the fixed tube (61), and the contact plate (66) is attached to the lower end surface of the contact back plate (4).
2. The device for adjusting the bending amount of large-size substrate evaporation according to claim 1 is characterized in that: A plurality of slots (201) are evenly arranged around the top of the mask frame (2), the bearing seat (21) is snap-fitted and installed inside the slots (201), and the height of the bearing seat (21) is smaller than the depth of the slots (201).
3. The device for adjusting the bending amount of large-size substrate evaporation according to claim 1, characterized in that: A groove (211) is provided at one end of the top of the supporting seat (21) located below the glass substrate (3); the lifting plate (22) is mounted on the top of the supporting seat (21) by snapping into the groove (211); and a fastening bolt (24) is provided at one side of the top of the lifting plate (22) located on the glass substrate (3); the fastening bolt (24) passes through the lifting plate (22) and is threadedly mounted inside the supporting seat (21); and the upper end surface of the lifting plate (22) is flush with the upper end surface of the mask frame (2).
4. The device for adjusting the bending amount of large-size substrate evaporation according to claim 1, characterized in that: The outer wall of the fixing cylinder (61) is provided with a threaded ring (612), the top of the bearing seat (21) is located on one side of the glass substrate (3) and is provided with a threaded groove (212), and the fixing cylinder (61) is installed inside the bearing seat (21) through the matching threads of the threaded ring (612) and the threaded groove (212).
5. The device for adjusting the bending amount of large-size substrate evaporation according to claim 1, characterized in that: The interior of the fixed cylinder (61) is provided with a cavity (611) for the sliding of the limiting ring (64); the buffer column (63) is slidably installed in the interior of the cavity (611) through the limiting ring (64); and the end surface area of the limiting ring (64) is larger than the opening area of the cavity (611).
6. The device for adjusting the bending amount of large-size substrate evaporation according to claim 1, characterized in that: The upper end surface of the contact plate (66) is provided with a buffer pad (661), and the contact plate (66) is attached to the lower end surface of the contact back plate (4) through the buffer pad (661), and the lifting plate (22) and the buffer pad (661) are both made of rubber.
7. The device for adjusting the bending amount of large-size substrate evaporation according to claim 1, characterized in that: A top plate (62) for limiting the position of the fixed tube (61) is arranged on the top of the fixed tube (61), and the top plate (62) is attached to the upper end surface of the supporting seat (21), the sum of the heights of the top plate (62) and the contact plate (66) is the same as the distance between the upper end surface of the supporting seat (21) and the upper end surface of the glass substrate (3), and the upper end surface of the contact plate (66) is flush with the upper end surface of the glass substrate (3).
8. The device for adjusting the bending amount of large-size substrate evaporation according to claim 1, characterized in that: One end of the supporting seat (21) away from the glass substrate (3) passes through the mask frame (2) and extends to the outside thereof, and a lifting frame is arranged inside the evaporation machine around the outside of the mask frame (2), and one end of the top of a plurality of the supporting seats (21) located outside the mask frame (2) is provided with an extension bolt (23), and the extension bolt (23) passes through the lifting frame and is threadedly installed inside the supporting seat (21).