Metal mask testing platform and testing system

Abstract

The application discloses a kind of metal mask testing platform and metal mask testing system, and testing platform includes calibration base, multiple fine adjustment locking mechanism, deflection fine adjustment pre-tightening mechanism, plane fine adjustment mechanism, final locking mechanism, installation backboard and two-dimensional motion module.The calibration base is provided with rotary positioning shaft and installation reference;Fine adjustment locking mechanism outputs micrometer level displacement by fine adjustment head and utilizes the boss mechanism of semicircular pressing block to lock horizontal degree of freedom;Deflection fine adjustment pre-tightening mechanism continuously outputs pre-tightening force by elastic component to eliminate deflection adjustment transmission gap;Plane fine adjustment mechanism adopts three-point determination one plane way to correct mask flatness;Final locking mechanism cooperates upper and lower limit block to lock vertical degree of freedom.The application also discloses a testing system comprising the testing platform and optical machine module.The application eliminates thread transmission gap by multiple mechanism cooperation, realizes mask multiple degree of freedom micrometer level precision adjustment and reliable locking.

Description

Technical Field

[0001] This invention belongs to the technical field of precision testing equipment and semiconductor display manufacturing equipment, specifically relating to a metal mask test stage and a metal mask test system. It is mainly used in the manufacturing process of organic light-emitting diode display panels to perform micron-level precision clamping and optical testing on the flatness, positioning mark parallelism, and geometric dimensions of high-precision metal masks. Background Technology

[0002] In the field of organic light-emitting diode (OLED) display panel manufacturing, high-precision metal masks are the core fixtures that determine the quality of the evaporation process. The metal mask contains tens of thousands of micron-sized openings, and their positional accuracy and flatness directly affect the deposition position and shape of the pixels. Therefore, before the mask is used, its geometric dimensions, flatness, and the parallelism of the positioning marks must be precisely inspected using a dedicated testing stage. Whether the clamping accuracy and stability of the testing stage can reach the micron level is a crucial prerequisite for determining the reliability of the final test results.

[0003] Existing mask testing stages mostly employ a mechanical clamping screw and fixed stop clamping method, with the mask edge being pushed and positioned by manually rotating the screw. This method has significant transmission backlash, which easily generates backlash during micron-level back-and-forth adjustments, making it difficult to accurately converge the yaw angle adjustment. Furthermore, the rigid clamping component directly contacts the mask edge, easily causing localized plastic deformation or surface scratches on the thin plate edge, affecting the mask's overall accuracy. In addition, the structural resonance of the testing stage itself and environmental micro-vibration interference also limit further improvements in testing accuracy.

[0004] Existing clamping devices typically rely solely on lateral multi-point clamping to fix the mask, lacking effective uniform constraint in the vertical direction. During high-speed scanning and inspection, the mask is prone to vertical movement due to acceleration and deceleration inertia. Furthermore, changing masks of different specifications requires extensive manual readjustment, resulting in low changeover efficiency. Therefore, there is an urgent need for a test platform technology solution that can eliminate transmission backlash with micron-level precision, achieve reliable multi-degree-of-freedom locking, effectively suppress vibration interference, and be compatible with rapid changeover of multiple specifications. Summary of the Invention

[0005] The purpose of this invention is to provide a metal mask testing platform and testing system to solve the problems of micro-motion deviations in existing mask clamping and testing devices when adjusting micron-level flatness and yaw angle. These problems include adjustment backlash caused by thread transmission clearance, inability to dynamically maintain constant preload, and unreliable locking of horizontal and vertical degrees of freedom.

[0006] The first objective of this invention is to provide a metal mask test stage, comprising: The calibration base has a support surface and a rotating positioning shaft protruding from the support surface. The support surface is used to place the metal mask plate, and the rotating positioning shaft is used to allow the metal mask plate to rotate around it when it sways. Multiple installation references are arranged around the calibration base. Multiple fine-tuning locking mechanisms are installed on the mounting reference around the calibration base. Each fine-tuning locking mechanism includes a fine-tuning head, a clamping mechanism, and a guide groove for guiding the clamping mechanism. The fine-tuning head has a micrometer screw. The end of the micrometer screw is used to drive the clamping mechanism to abut against the side of the metal mask plate to output micrometer-level horizontal displacement and fix the horizontal degree of freedom of the metal mask plate. The yaw fine-tuning preload mechanism is mounted on the calibration base. The yaw fine-tuning preload mechanism includes an elastic component and a preload block. The elastic component forces the preload block to press against the side of the metal mask plate, providing a continuous preload force in the direction of the rotation positioning axis, so that the metal mask plate remains in contact with the component that drives its yaw during yaw adjustment. The planar fine-tuning mechanism is installed on the calibration base. The planar fine-tuning mechanism is equipped with multiple height-adjustable support members. The top of the support members supports the bottom surface of the metal mask plate. The horizontal flatness of the metal mask plate is corrected by adjusting the height of the support members. The final locking mechanism has a vertical pressing part, which is used to press the metal mask plate vertically onto the support surface of the calibration base to lock the vertical degree of freedom. The two-dimensional motion module and the mounting backplate are fixedly connected to the mounting backplate. The calibration base is connected to the motion output end of the two-dimensional motion module. The two-dimensional motion module drives the calibration base and the locked metal mask plate to translate along the first and second horizontal axes that are orthogonal to each other.

[0007] Furthermore, the test platform also includes an air-bearing vibration isolation module, which is located at the bottom of the mounting backplate. The air-bearing vibration isolation module includes at least three air-bearing vibration isolation feet. The air-bearing vibration isolation feet form an air film through compressed air to isolate ground vibration, and the height of the air-bearing vibration isolation feet can be independently adjusted to maintain the horizontal attitude of the mounting backplate.

[0008] Furthermore, the non-working surfaces of the calibration base and the mounting backplate are equipped with a constraint layer damping structure, which includes alternating layers of viscoelastic damping material and constraint steel plates, used to suppress resonance peaks and reduce structural noise.

[0009] Furthermore, the protrusion structure of the calibration base has multiple sets of vacuum adsorption holes, which are connected to a vacuum pump through air channels to form a negative pressure adsorption force after the metal mask is placed in place, so that the metal mask adheres to the upper surface of the protrusion structure. A ring-shaped flexible sealing gasket is set around the vacuum adsorption holes. The ring-shaped flexible sealing gasket is made of low-hardness silicone material to ensure airtightness and prevent indentation from forming on the lower surface of the metal mask. The negative pressure adsorption force, the lateral pre-tightening force applied by the fine-tuning locking mechanism, and the vertical clamping force applied by the final locking mechanism constitute a composite fixing system.

[0010] Furthermore, the calibration base and the mounting backplate are connected via a modular quick-change base system, which includes a locating pin, a conical locating structure, and a quick-locking handle. The locating pin is located at the bottom of the calibration base and has a precision clearance fit with the locating pin hole on the mounting backplate. The conical locating structure is located at the bottom of the calibration base and has a self-centering taper fit with the conical mating surface on the mounting backplate to achieve positioning. The quick-locking handle adopts an eccentric cam structure, and the locking or unlocking between the calibration base and the mounting backplate is completed by rotation, so that the repeatability of the calibration base replacement positioning accuracy reaches the micron level.

[0011] Furthermore, the boss structure of the calibration base adopts a replaceable modular boss module, which is equipped with boss modules of various sizes to adapt to metal mask plates of different sizes; the calibration base is provided with a dovetail mounting groove, and the fixing seat of the fine-tuning locking mechanism adopts a sliding locking structure with the dovetail mounting groove. The fixing seat can slide and lock along the dovetail mounting groove to adjust the installation position of the fine-tuning locking mechanism.

[0012] The second objective of this invention is to provide a metal mask testing system, including the aforementioned metal mask testing stage, and further including a Z-axis module, a rotation module, a pitch module mounted on a mounting backplate, and an optomechanical module mounted on these modules. The optomechanical module is used to perform optical calibration and defect detection on the metal mask.

[0013] The present invention has the following beneficial effects: (1) The metal mask test stage and test system of the present invention achieves multi-degree-of-freedom micron-level precision adjustment and reliable locking of the metal mask through the coordinated work of the fine-tuning locking mechanism, the yaw fine-tuning pre-tightening mechanism and the final locking mechanism. The yaw fine-tuning pre-tightening mechanism uses an elastic component to continuously output a pre-tightening force pointing towards the rotation positioning axis, effectively eliminating the thread transmission backlash and ensuring the smoothness of the yaw adjustment and the absence of backlash.

[0014] (2) This invention covers the contact surfaces of the clamping mechanism and the pre-clamping block with a flexible polyurethane or polyimide layer, which buffers local contact stress while transmitting the pre-clamping force, thus avoiding plastic deformation or surface scratches at the edges of the mask plate. The vacuum adsorption holes, together with the low-hardness silicone annular flexible sealing gasket, form a uniform negative pressure adsorption force, which, together with the lateral pre-clamping force and the vertical clamping force, constitutes a composite fixing system, enabling the mask plate to obtain uniform and stable constraints in both the horizontal and vertical directions, significantly improving the clamping stiffness and vibration resistance.

[0015] (3) The modular quick-change base system of the present invention achieves rapid replacement of calibration bases of different specifications with micron-level repeatability by combining positioning pins, conical positioning structures and eccentric cam quick-locking handles. The boss structure of the calibration base adopts a detachable modular design, and the fixed seat of the fine-tuning locking mechanism and the dovetail mounting groove adopt a sliding locking structure, so that the same platform can flexibly adapt to metal mask plates of various sizes and specifications, greatly improving clamping compatibility and replacement efficiency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a structural diagram of the metal mask plate test stage in an embodiment of the present invention; Figure 2 Exploded view of the fine-tuning locking mechanism and the yaw fine-tuning pre-tightening mechanism of the metal mask plate test stage in the embodiment of the present invention; Figure 3 Exploded view of the planar fine-tuning mechanism and the final locking mechanism of the metal mask plate test stage in an embodiment of the present invention; Figure 4 This is a front view of the metal mask plate test stage in an embodiment of the present invention; Figure 5 This is an enlarged view of point A in the main view of the metal mask plate test stage in an embodiment of the present invention. Figure 6 This is a front view of the calibration base of the metal mask plate test stage in an embodiment of the present invention; Figure 7 This is a schematic diagram of the metal mask testing system in an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached drawings: 1-Metal mask plate; 2-Calibration base; 21-Rotary positioning shaft; 22-Rotary positioning reference line; 23-First vertical degree of freedom limit block; 24-Fine adjustment line; 25-Second vertical degree of freedom limit block; 26-Dovetail mounting groove; 27-Pre-tightening mounting groove; 28-Hollow process hole; 3-Fine adjustment locking mechanism; 31-Fine adjustment head; 32-Fixed seat; 33-Pressure mechanism; 34-Guide groove; 4-Oblique fine adjustment pre-tightening mechanism; 41-Oblique fixed seat; 42-Guide groove; 43-Elastic mechanism; 44-Pre-tightening block; 5-Plane fine adjustment mechanism; 6-Final locking mechanism. Detailed Implementation

[0019] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0020] To fully understand this invention, detailed steps and structures will be presented in the following description to illustrate the technical solution of this invention. Preferred embodiments of the invention are described in detail below; however, in addition to these detailed descriptions, the invention may have other embodiments.

[0021] Example 1

[0022] like Figures 1 to 6 In one embodiment of the metal mask test stage of the present invention, the metal mask test stage is used to precisely clamp and position the metal mask 1 during optical inspection, adjusting its pose parameters such as flatness and yaw angle to micrometer-level accuracy, and then cooperating with the optomechanical module to complete a comprehensive scanning inspection. The test stage includes a calibration base 2, multiple fine-tuning and locking mechanisms 3, a yaw fine-tuning pre-tightening mechanism 4, a planar fine-tuning mechanism 5, a final locking mechanism 6, a mounting backplate, and a two-dimensional motion module.

[0023] The calibration base 2 serves as the installation reference for the entire adjustment mechanism and the supporting foundation for the metal mask plate 1. Its upper surface forms a support surface, with a rotating positioning shaft 21 protruding from the center of the support surface. The rotating positioning shaft 21 acts as a rotation center when the metal mask plate 1 undergoes fine-tuning of its yaw angle. After the positioning hole on the metal mask plate 1 is fitted with the rotating positioning shaft 21, the mask plate can rotate clockwise or counterclockwise around this shaft at a small angle. The support surface of the calibration base 2 is also machined with a rotating positioning reference line 22 and eight fine-tuning lines 24. The rotating positioning reference line 22 is used to visually or with the aid of an optical system to calibrate the rotation angle during yaw adjustment. The fine-tuning lines 24 are distributed within a square area of ​​the support surface and are used to calibrate the initial position of the metal mask plate 1 in mutually orthogonal X and Y directions. The calibration base 2 has a first vertical degree-of-freedom limiting block 23 and a second vertical degree-of-freedom limiting block 25 positioned around the periphery of the support surface. The first vertical degree-of-freedom limiting block 23 and the second vertical degree-of-freedom limiting block 25 are arranged one above the other to restrict the vertical position of the metal mask plate 1 from both vertical directions, preventing it from jumping in the vertical direction. These two limiting blocks cooperate with the vertical pressing part of the final locking mechanism 6 to lock the vertical degree of freedom. The support surface of the calibration base 2 is set with a boss structure in the middle. When the metal mask plate 1 is placed, its bottom surface sits on the upper surface of the boss structure. The design of the boss structure makes the metal mask plate 1 evenly stressed on each side when placed, thereby effectively avoiding the initial warping of the thin plate edge.

[0024] The calibration base 2 has multiple mounting references arranged around its periphery, namely dovetail mounting slots 26 and pre-tightening mounting slots 27. Multiple fine-tuning locking mechanisms 3 are respectively installed on the mounting references around the calibration base 2. The dovetail mounting slots 26 are used to install the fine-tuning locking mechanisms 3, and the pre-tightening mounting slots 27 are used to install the wobble fine-tuning pre-tightening mechanisms 4. The calibration base 2 also has hollow process holes 28 that extend through its thickness direction to reduce the overall load on the calibration base 2 and facilitate internal wiring or ventilation pipe arrangement.

[0025] Multiple fine-tuning locking mechanisms 3 are arranged around the periphery of the calibration base 2. Their specific number is determined by the size and shape of the metal mask plate 1, and they are typically distributed around the four sides of the mask plate. Each fine-tuning locking mechanism 3 consists of a fine-tuning head 31, a fixed base 32, a guide groove 34, and a clamping mechanism 33. The fixed base 32 is installed in the dovetail mounting groove 26 on the periphery of the calibration base 2. The fixed base 32 is fixedly connected to the dovetail mounting groove 26 by fasteners, providing a stable mounting foundation for the entire fine-tuning locking mechanism 3 on the calibration base 2. The fine-tuning head 31 has a micrometer screw driven by a threaded pair inside, and the end of the micrometer screw is connected to the clamping mechanism 33. The clamping mechanism 33 is a semi-circular pressure block that slides within the guide groove 34. The front end of the semi-circular pressure block has a boss structure that abuts against the side of the metal mask plate 1. The guide groove 34 is located on the fixed base 32, providing linear motion guidance for the semi-circular pressure block. When the operator rotates the knob of the micrometer head, the micrometer screw drives the semi-circular pressure block to move forward or backward along the guide groove 34 with micrometer-level resolution. The front end of the semi-circular pressure block abuts against the side of the metal mask plate 1, thereby pushing the mask plate or releasing the constraint on the mask plate, realizing fine-tuning of the mask plate in the horizontal plane for translation and yaw. When the adjustment is in place and locking is required, the semi-circular pressure block remains in place under the push of the micrometer screw. The self-locking characteristic of the micrometer screw locks the semi-circular pressure block in the guide groove 34. The front end of the semi-circular pressure block continues to press against the side of the metal mask plate 1, locking the horizontal degree of freedom of the mask plate. The position of the semi-circular pressure block that has been adjusted will not change during the locking process, thus ensuring the maintenance of adjustment accuracy. When the boss structure at the front end of the clamping mechanism 33 contacts the side of the metal mask plate 1, it distributes the clamping force evenly along the thickness direction of the mask plate, so that the upper and lower ends of the side of the mask plate are subjected to symmetrical and consistent constraint forces. This avoids local warping of the mask plate edge due to single-point concentrated contact, thereby ensuring that the mask plate can maintain the planar accuracy obtained during placement during the clamping process. This effectively solves the problem of poor edge warping accuracy that is easily caused by rigid point contact.

[0026] The yaw fine-tuning pre-tightening mechanism 4 is installed in the pre-tightening mounting groove 27 of the calibration base 2. The yaw fine-tuning pre-tightening mechanism 4 includes a yaw fixing seat 41, a yaw guide groove 42, an elastic mechanism 43, and a pre-tightening block 44. The yaw fixing seat 41 is fixedly connected to the pre-tightening mounting groove 27 by fasteners. The yaw guide groove 42 is formed on the yaw fixing seat 41, and the elastic mechanism 43 is housed inside the yaw guide groove 42. The elastic mechanism 43 is a spring or a sheet. The pre-tightening block 44 is slidably disposed in the yaw guide groove 42. One end of the pre-tightening block 44 contacts the elastic mechanism 43, and the other end extends out of the guide groove 42. Its end is provided with a boss structure, which abuts against the side of the metal mask plate 1. The elastic mechanism 43 continuously applies an elastic thrust to the pre-tightening block 44, and the direction of the thrust is towards the area where the rotary positioning shaft 21 on the calibration base 2 is located. After the metal mask 1 is installed, the preload block 44 always presses the side of the mask with elastic force, providing a stable reverse preload force for the yaw adjustment. This preload force eliminates the transmission gap between the micrometer screw and the mask, ensuring a linear correspondence between the feed amount of the micrometer head 31 and the rotation angle of the mask during yaw fine-tuning, resulting in smooth adjustment without backlash. The boss structure at the end of the preload block 44 forms uniform contact with the side of the mask under the thrust of the elastic mechanism 43. The boss structure symmetrically distributes the preload force along the thickness direction of the mask, ensuring balanced force on the upper and lower sides of the mask. This design ensures that during yaw fine-tuning, the mask will not experience slight vertical tilting or edge warping due to uneven force under the continuous action of the preload force, guaranteeing the accuracy and stability of the yaw adjustment. The planar fine-tuning mechanism 5 is mounted on the calibration base 2 and is used to adjust the horizontal flatness of the metal mask 1. The planar fine-tuning mechanism 5 has four independently adjustable supports, including three main adjustment supports and one auxiliary support. The three main adjustment supports are arranged below the bottom surface of the metal mask 1 according to the geometric principle that three points determine a plane. The auxiliary support is located outside the plane defined by the three main supports. Its function is to rotate the main supports until they just contact the bottom surface of the mask and apply a slight preload after the flatness adjustment is completed, forming an auxiliary support to prevent local deformation of the mask due to its own weight or suspension. The top of each support directly supports the bottom surface of the metal mask 1. By rotating each support, the height position of its top is changed, thereby correcting the height consistency of each feature point on the upper surface of the mask, ensuring that the flatness of the entire plane meets the inspection requirements.

[0027] The final locking mechanism 6 is used to lock the vertical degree of freedom of the metal mask 1 after the horizontal flatness and yaw angle have been adjusted to the set accuracy. The final locking mechanism 6 has a vertical pressing part, which includes multiple vertical pressing members. The vertical pressing members press down on the upper surface edge of the metal mask 1 from top to bottom. They cooperate with the first vertical degree of freedom limiting block 23 and the second vertical degree of freedom limiting block 25 on the calibration base 2 to press the metal mask 1 vertically onto the support surface of the calibration base 2. This locks the vertical degree of freedom of the mask from both the top and bottom, preventing vertical jump of the mask due to the acceleration and deceleration of the two-dimensional motion module during subsequent scanning and detection. The horizontal degree of freedom of the metal mask 1 is locked by the pressing mechanism 33 of each fine-tuning locking mechanism 3 after locking the micrometer screw.

[0028] The mounting backplate serves as a rigid support base for all modules and components, and a two-dimensional motion module is fixed on the mounting backplate. The motion output end of the two-dimensional motion module is connected to the calibration base 2. The two-dimensional motion module includes a first horizontal axis motion mechanism and a second horizontal axis motion mechanism that are orthogonal to each other, which can drive the calibration base 2 and the metal mask 1 locked on it to make precise positioning and translation along the orthogonal X and Y directions. The two-dimensional motion module works with the optomechanical module to make each area to be inspected on the mask pass through the field of view of the optomechanical module one by one during the scanning and inspection process, completing the optical inspection of the entire mask surface.

[0029] In practical testing applications, the operation procedure follows these steps. First, loosen the clamping mechanisms 33 in all the fine-tuning locking mechanisms 3, and rotate the knobs of each fine-tuning head 31 so that the end of the micrometer screw retracts beyond the area defined by the square reference lines on the calibration base 2. At this point, the area above the boss structure of the calibration base 2 is completely open, and there is no interference in the placement area. Then, using a robotic arm or manually, place the metal mask 1 to be tested smoothly onto the boss structure of the calibration base 2, with the bottom surface of the mask in contact with the upper surface of the boss structure, and the sides of the mask still in a free state. Next, rotate the fine-tuning heads 31 of the fine-tuning locking mechanisms 3 located in the four corner areas of the mask, so that the end of the micrometer screw advances until the clamping mechanism 33 contacts the corresponding side of the mask, but only a slight pre-tightening force is applied to prevent the mask from undergoing elastic deformation. At this point, the metal mask 1 is confined within the square reference lines and is in a pre-positioned but not completely fixed state. Then, fine-tuning of the horizontal flatness is performed. A dial indicator or laser displacement sensor is fixedly installed on the moving part of the two-dimensional motion module, so that the probe of the dial indicator contacts the upper surface of the metal mask plate 1. The operator rotates the three main adjustment supports of the plane fine-tuning mechanism 5 one by one, observes the changes in the dial indicator readings, and adjusts repeatedly until the height difference of multiple feature points on the upper surface of the mask plate converges to the allowable flatness range. After confirming that the standard is met, the auxiliary support is rotated so that its top just contacts the bottom surface of the mask plate and a small amount of pre-tightening force is applied to complete the flatness correction. Subsequently, fine-tuning of the yaw angle is performed. The fine-tuning heads 31 of several fine-tuning locking mechanisms 3 related to the yaw adjustment direction are loosened by a certain distance, so that the micrometer screws of these fine-tuning heads 31 drive the clamping mechanism 33 to temporarily disengage from the side of the mask plate. At this time, the rotational freedom of the mask plate in the horizontal plane is only constrained by the remaining unloosened fine-tuning locking mechanism 3 and the yaw fine-tuning pre-tightening mechanism 4. The elastic mechanism 43 of the yaw fine-tuning pre-tightening mechanism 4 pushes the pre-tightening block 44 to constantly press against the side of the mask plate, providing a continuous pre-tightening force pointing in the direction of the rotation positioning axis 21. The operator rotates the two fine-tuning heads 31 used for yaw adjustment. These two fine-tuning heads 31 form a force couple at diagonal positions or on the same side of the mask plate, pushing the metal mask plate 1 to rotate slightly clockwise or counterclockwise around the rotation positioning axis 21 according to the feed resolution of the fine-tuning heads. During this process, the optical calibration system measures the parallelism deviation between the reference mark on the mask plate and the motion axis of the two-dimensional motion module in real time. The operator continuously adjusts according to the readings until the parallelism deviation is eliminated and the straightness reaches the set accuracy, at which point the yaw adjustment stops. After confirming that the horizontal flatness and yaw angle meet the standards, tighten the fine adjustment heads 31 of all fine adjustment locking mechanisms 3 in sequence, so that the micrometer screw drives the semi-circular pressure block to move along the guide groove 34 and press against the side of the metal mask plate 1 to lock the horizontal degree of freedom of the mask plate; at the same time, tighten the multiple vertical clamping parts of the final locking mechanism 6 to lock the vertical degree of freedom of the mask plate, so that the metal mask plate 1 is completely fixed on the calibration base 2.Finally, the two-dimensional motion module is activated, and in conjunction with the optomechanical module, a comprehensive scan and inspection of the metal mask 1 is performed.

[0030] In one specific embodiment, the surfaces of the clamping mechanism 33 of the fine-tuning locking mechanism 3 that contact the metal mask plate 1, and the surfaces of the pre-tightening block 44 of the yaw fine-tuning pre-tightening mechanism 4 that contact the metal mask plate 1, are both covered with a flexible polyurethane layer or a polyimide film layer. The flexible polyurethane layer or the polyimide film layer is firmly attached to the contact end face of the corresponding metal part by bonding or plating. When the clamping mechanism 33 or the pre-tightening block 44 applies a clamping force or a pre-tightening force to the metal mask plate 1, the flexible layer first contacts the edge of the mask plate and undergoes a slight elastic deformation. While transmitting the required force, it effectively buffers local contact stress, preventing the edge of the mask plate from undergoing plastic deformation or being scratched due to direct hard contact with the metal part, thereby protecting the edge integrity and dimensional accuracy of the mask plate.

[0031] In one specific embodiment, the test platform further includes an air-bearing vibration isolation module, which is disposed at the bottom of the mounting backplate. The mounting backplate is supported on the ground or workbench by the air-bearing vibration isolation module. The air-bearing vibration isolation module includes at least three air-bearing vibration isolation feet, each of which has an air chamber inside. When compressed air is introduced into the air chamber, the gas is discharged from the throttling orifice at the bottom of the air-bearing vibration isolation foot and forms an air film between the ground and the bottom surface of the air-bearing vibration isolation foot. This air film physically isolates the mounting backplate and its components above it from the ground, effectively attenuating high-frequency micro-vibrations transmitted from the ground. At the same time, the height of each air-bearing vibration isolation foot can be independently adjusted by adjusting the air pressure or a mechanical screw mechanism. During the installation of the test platform, the height of each air-bearing vibration isolation foot is corrected one by one using a level, achieving precise adjustment of the horizontal attitude of the mounting backplate and reducing tilting errors caused by uneven mounting foundations.

[0032] In one specific embodiment, both the non-working surfaces of the calibration base 2 and the mounting backplate are provided with constraint layer damping structures. The constraint layer damping structure is composed of alternating layers of viscoelastic damping material and constraint steel plates. Specifically, in the non-working areas of the calibration base 2 and the mounting backplate where precise fitting or installation of other components is not required, a layer of viscoelastic damping material is first coated, then a layer of constraint steel plate is placed on top, and then another layer of viscoelastic damping material and constraint steel plate are laid on top of the constraint steel plate, forming a multi-layered composite structure. When the test stage undergoes high-speed scanning motion driven by the two-dimensional motion module or vibrates due to external excitation, the viscoelastic damping material layer dissipates vibration energy into heat energy through its own shear deformation, while the constraint steel plate layer enhances energy dissipation efficiency by limiting excessive deformation of the damping material. This structure can effectively suppress the resonance peak of the test stage in a specific frequency range and reduce structural noise during the scanning process.

[0033] In one specific embodiment, the protrusion structure of the calibration base 2 has multiple sets of vacuum adsorption holes, which are evenly distributed on the upper surface of the protrusion structure. Each vacuum adsorption hole is connected to one or more air passages through an air channel inside the calibration base 2. The air passages are connected to an external vacuum pump through pipelines. When the metal mask 1 is placed on the protrusion structure, the vacuum pump is started to evacuate air, creating a negative pressure in the vacuum adsorption hole area. The adsorption force generated by the negative pressure pulls the metal mask 1 downwards evenly and tightly, so that the lower surface of the mask is completely in contact with the upper surface of the protrusion structure. An annular flexible sealing gasket is also provided around the opening of each vacuum adsorption hole. The annular flexible sealing gasket is made of low-hardness silicone material. Its texture is soft, and under negative pressure, the sealing gasket undergoes elastic compression deformation under the action of external atmospheric pressure, sealing the area around the adsorption hole and ensuring continuous and stable adsorption force. At the same time, the soft properties of silicone prevent it from causing indentation damage to the lower surface of the mask when in contact with it. The negative pressure adsorption force generated by the vacuum adsorption hole, together with the pre-tightening force applied laterally by the fine-tuning locking mechanism 3 and the vertical clamping force of the final locking mechanism 6, constitute a composite fixing system, which enables the metal mask plate 1 to obtain uniform and stable constraint force on all sides in the horizontal direction and on the top and bottom surfaces in the vertical direction, significantly improving the clamping stiffness and vibration resistance.

[0034] In one specific embodiment, the calibration base 2 and the mounting backplate are detachably connected via a modular quick-change base system. The modular quick-change base system includes positioning pins, a conical positioning structure, and a quick-locking handle. Positioning pins are located at the bottom of the calibration base 2, typically two or three cylindrical pins. Corresponding positioning pin holes are machined on the mounting backplate, and a precision clearance fit is used between the positioning pins and the positioning pin holes to achieve high repeatability while ensuring easy insertion and removal. The conical positioning structure is located at the center or edge of the bottom of the calibration base 2, and a corresponding conical mating surface is provided on the mounting backplate. The conical positioning structure employs a self-centering taper design. When the calibration base 2 is placed on the mounting backplate and the conical surface is guided into the mating surface, the two conical surfaces fit together under locking force, automatically correcting the position and centering accuracy of the calibration base 2 in the horizontal plane. The quick-locking handle employs an eccentric cam structure. The handle is mounted on the mounting backplate via a rotating shaft. Its cam end engages with a slot or pull rod on the calibration base 2. When the operator rotates the handle by a certain angle, the radial change in the eccentric cam is converted into a vertical tension force on the calibration base 2, pressing and locking it onto the mounting backplate. Reversing the rotation of the handle releases the tension force, allowing the calibration base 2 to be removed. Through the combined use of the locating pin, conical locating structure, and quick-locking handle, the repeatability of the calibration base 2 after replacement can reach the micrometer level, and the replacement operation requires no additional tools, making it highly efficient and convenient.

[0035] In one specific embodiment, the boss structure of the calibration base 2 adopts a replaceable modular boss module. Based on the size specifications of the metal mask 1 to be tested, a boss module of the appropriate size is selected and installed on the corresponding mounting interface of the calibration base 2, thus adapting to masks of different sizes. Furthermore, the dovetail mounting groove 26 extends along the periphery of the calibration base 2, and the bottom of the fixing seat 32 of the fine-tuning locking mechanism 3 is provided with a slider structure that cooperates with the dovetail mounting groove 26; the two constitute a sliding locking structure. When it is necessary to adjust the installation position of the fine-tuning locking mechanism 3 to accommodate masks with different aspect ratios or irregular shapes, the locking element on the fixing seat 32 is loosened, the fixing seat 32 is slid along the dovetail mounting groove 26 to the desired position, and the fixing seat 32 is locked again to complete the position adjustment. This design allows the same test platform to be compatible with the clamping requirements of various specifications of metal mask 1 by replacing the boss module and adjusting the installation position of the fine-tuning locking mechanism 3.

[0036] Example 2 This embodiment provides a metal mask testing system, such as Figure 7 As shown, the testing system includes the metal mask test stage described in Example 1, and also includes a Z-axis module, a rotation module, a pitch module mounted on a mounting backplate, and an optomechanical module mounted on these modules. The Z-axis module is used to drive the optomechanical module to move up and down in the vertical direction to complete focusing. The rotation module and the pitch module are used to adjust the rotational and pitch attitudes of the optomechanical module, respectively. The optomechanical module is used to perform optical calibration and high-resolution defect detection on the metal mask after it has been clamped and positioned on the test stage. The two-dimensional motion module drives the calibration base 2 and the mask to perform planar scanning motion in the X and Y directions. Combined with the attitude adjustment of the optomechanical module by the Z-axis module, the rotation module, and the pitch module, automated and precise inspection of the entire surface of the metal mask is achieved.

[0037] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, nor is it limited to the metal mask test stage and test stage. Devices and structures not described in detail herein should be understood as being implemented in a manner common to the art. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. This does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention are still within the scope of protection of the present invention.

Claims

1. A metal mask test stage, characterized in that, include: The calibration base has a support surface and a rotating positioning shaft protruding from the support surface. The support surface is used to place the metal mask plate, and the rotating positioning shaft is used to allow the metal mask plate to rotate around it when it sways. Multiple installation references are arranged around the calibration base. Multiple fine-tuning locking mechanisms are installed on the mounting reference around the calibration base. Each fine-tuning locking mechanism includes a fine-tuning head, a clamping mechanism, and a guide groove for guiding the clamping mechanism. The fine-tuning head has a micrometer screw. The end of the micrometer screw is used to drive the clamping mechanism to abut against the side of the metal mask plate to output micrometer-level horizontal displacement and fix the horizontal degree of freedom of the metal mask plate. The yaw fine-tuning preload mechanism is mounted on the calibration base. The yaw fine-tuning preload mechanism includes an elastic component and a preload block. The elastic component forces the preload block to press against the side of the metal mask plate, providing a continuous preload force in the direction of the rotation positioning axis, so that the metal mask plate remains in contact with the component that drives its yaw during yaw adjustment. The planar fine-tuning mechanism is installed on the calibration base. The planar fine-tuning mechanism is equipped with multiple height-adjustable support members. The top of the support members supports the bottom surface of the metal mask plate. The horizontal flatness of the metal mask plate is corrected by adjusting the height of the support members. The final locking mechanism has a vertical pressing part, which is used to press the metal mask plate vertically onto the support surface of the calibration base to lock the vertical degree of freedom. The two-dimensional motion module and the mounting backplate are fixedly connected to the mounting backplate. The calibration base is connected to the motion output end of the two-dimensional motion module. The two-dimensional motion module drives the calibration base and the locked metal mask plate to translate along the first and second horizontal axes that are orthogonal to each other.

2. The metal mask plate test stage according to claim 1, characterized in that: The calibration base also includes a first vertical degree of freedom limiting block and a second vertical degree of freedom limiting block formed around the support surface. The first vertical degree of freedom limiting block and the second vertical degree of freedom limiting block cooperate with the vertical clamping part to restrict the vertical position of the metal mask plate from the upper and lower sides.

3. The metal mask plate test stage according to claim 1, characterized in that: The clamping mechanism in the fine-tuning locking mechanism is a semi-circular pressure block. The semi-circular pressure block is connected to the end of the micrometer screw. The micrometer screw drives the semi-circular pressure block to move along the guide groove. When locking, the semi-circular pressure block presses and fixes the side of the metal mask plate.

4. The metal mask plate test stage according to claim 1, characterized in that: The yaw fine-tuning pre-tightening mechanism also includes a yaw fixing seat and a yaw guide groove. The elastic component is housed in the yaw guide groove, and the pre-tightening block is slidably disposed in the yaw guide groove and extends out to abut against the metal mask plate.

5. The metal mask plate test stage according to claim 1 or 4, characterized in that: The elastic component is a spring or a sheet.

6. The metal mask test stage according to claim 1, characterized in that: The planar fine-tuning mechanism includes three main adjustment supports and one auxiliary support. The three main adjustment supports are arranged in a three-point configuration to define a plane. The auxiliary support is used to provide auxiliary support by contacting the bottom surface of the metal mask after the main adjustment supports have completed their adjustment, thus preventing local deformation of the metal mask.

7. The metal mask test stage according to claim 1, characterized in that: The final locking mechanism includes multiple vertical clamping elements that press the metal mask plate against the support surface from top to bottom.

8. The metal mask test stage according to claim 1, characterized in that: The clamping mechanism in the fine-tuning locking mechanism has a boss structure at one end facing the side of the metal mask, and the pre-tightening block in the yaw fine-tuning pre-tightening mechanism has a boss structure at one end facing the side of the metal mask. The boss structure contacts the side of the metal mask and applies a locking force or pre-tightening force, so that the side of the metal mask is subjected to uniform force in the thickness direction.

9. The metal mask test stage according to claim 8, characterized in that: The surfaces of the clamping mechanism in the fine-tuning locking mechanism that contact the metal mask plate, and the surfaces of the pre-tightening block in the yaw fine-tuning pre-tightening mechanism that contact the metal mask plate, are all covered with a polyurethane flexible layer or a polyimide film layer. The polyurethane flexible layer buffers the contact stress while transmitting the pre-tightening force, preventing plastic deformation or surface scratches on the edge of the metal mask plate.

10. A metal mask testing system, comprising a metal mask testing stage as described in any one of claims 1 to 9, characterized in that, It also includes a Z-axis module, a rotation module, a pitch module mounted on the mounting backplate, and an optomechanical module mounted on these modules. The optomechanical module is used for optical calibration and defect detection of the metal mask.

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