Vacuum coating system and control method capable of precisely controlling film thickness

Abstract

This invention discloses a vacuum coating system and control method for precisely controlling film thickness. The system includes a coating chamber, a cathode device, a workpiece carrier, and a driving device. The driving device drives the workpiece carrier to reciprocate linearly between a first position and a second position. During the movement of the workpiece carrier from the first position to the second position and from the second position to the first position, it passes through the cathode device and independently completes one coating cycle. The method includes dividing the layer to be coated into multiple sub-layers, pre-setting the thickness distribution of each sub-layer, and calculating the corresponding motion speed curve; during the coating of the first sub-layer, the film thickness distribution is detected in real time, and the thickness distribution of the second sub-layer is corrected accordingly; subsequent sub-layers are detected, corrected, and coated sequentially, gradually approaching the target film thickness. This invention achieves efficient and high-precision film thickness control through a bidirectional coating mode and a layer-by-layer correction strategy, suitable for various coating requirements such as uniform film layers and gradient color film layers.

Description

Technical Field

[0001] This invention relates to the field of vacuum coating technology, specifically to a vacuum coating system and control method that can precisely control film thickness. Background Technology

[0002] Vacuum coating technology (such as physical vapor deposition (PVD) and chemical vapor deposition (CVD) improves product performance by depositing a thin film on the product surface. In addition, different film materials and thicknesses can make the product surface present different colors. Therefore, vacuum coating technology is widely used in the electronics, optics and decoration industries, such as semiconductor devices, optical lenses, mobile phone back covers and decorative glass.

[0003] Film thickness is a crucial parameter affecting film performance and application effectiveness. For high-performance films with uniform thickness distribution, the accuracy and uniformity of film thickness directly impact key properties such as wear resistance and optical transmittance. Conversely, for gradient color films with uneven thickness distribution, the accuracy of thickness at various locations affects the accuracy of the film's color. Both of these requirements necessitate precise control of film thickness at different locations within the product, thus posing new challenges to coating technology.

[0004] For high-performance films with uniform thickness distribution, the current common practice is to improve the uniformity of working gas distribution, magnetic field uniformity, and temperature uniformity to improve the uniformity of film thickness distribution. However, since the above parameters cannot be completely uniformly distributed and cannot be controlled during the coating process, it is difficult to achieve precise control of film thickness.

[0005] For gradient color films with uneven thickness distribution, the thickness is currently typically controlled using a shielding plate of a specific shape. The shielding plate is placed between the cathode target and the workpiece to be coated (e.g., a substrate) to block some of the target particles sputtered onto the surface of the workpiece. This results in a thinner film on the blocked portion of the workpiece and a thicker film on the unblocked portion, achieving the gradient color effect. For example, Chinese patent application CN112811828A discloses a gradient color solar front panel, its manufacturing method, and a solar module packaging structure, achieving the gradient color coating effect by using shielding plates of different shapes to correct film thickness. However, for gradient color coating requirements involving multiple thickness variations and large-area workpieces, it is clearly difficult to design the shape of the shielding plate and precisely control the film thickness.

[0006] In summary, there is a need for a vacuum coating system and control method that can adapt to various film thickness requirements and achieve precise control of film thickness. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a vacuum coating system and control method with precise control of film thickness, which can adapt to various film thickness requirements and has high coating efficiency.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A vacuum coating system with precise control over film thickness includes a coating chamber, a cathode device, a workpiece carrier for supporting the workpiece to be coated, and a drive device for driving the workpiece carrier to move. The cathode device is installed in the coating chamber, and the drive device is connected to the workpiece carrier and can drive the workpiece carrier to reciprocate linearly between a first position and a second position. The workpiece carrier passes through the cathode device and completes one coating cycle independently during its movement from the first position to the second position and from the second position to the first position.

[0010] As a further improvement to the aforementioned vacuum coating system that can precisely control film thickness: The coating chamber is equipped with a guide device for guiding the reciprocating linear motion of the workpiece carrier.

[0011] The guiding device includes a permanent magnet guiding mechanism and multiple guide wheels. The permanent magnet guiding mechanism is located on the top of the workpiece carrier and is used for non-contact levitation positioning and guidance of the reciprocating linear motion of the workpiece carrier. The multiple guide wheels are located at the bottom of the workpiece carrier and are arranged sequentially at intervals in the direction of the reciprocating linear motion of the workpiece carrier to support and guide the reciprocating linear motion of the workpiece carrier.

[0012] The drive device is detachably connected to the workpiece carrier.

[0013] The driving device includes a motor, a driving rod, a driven rod, and a slider. The slider is slidably disposed in the coating chamber and its sliding direction is consistent with the reciprocating linear motion direction of the workpiece carrier. The driving rod is fixedly connected to the output shaft of the motor and is driven to rotate by the motor. The two ends of the driven rod are respectively hinged to the driving rod and the slider. The slider is detachably connected to the workpiece carrier through a coupling device. The driving rod, the driven rod, and the slider constitute a crank-slider mechanism that drives the reciprocating linear motion of the workpiece carrier.

[0014] The coupling device includes a plug pin, two cylinders, and a coupling hole on the workpiece carrier. The plug pin is mounted on the slider in a reciprocating motion and can be selectively inserted into and removed from the coupling hole through the reciprocating motion. One cylinder is used to drive the plug pin to insert into the coupling hole when the workpiece carrier is in a first position, and the other cylinder is used to drive the plug pin to remove from the coupling hole when the workpiece carrier is in a second position.

[0015] The coating chamber is also equipped with two shielding plates located on both sides of the cathode device, which are situated in the space between the cathode device and the workpiece carrier.

[0016] The coating chamber is equipped with a film thickness detection device for real-time detection of the thickness of the coated layer on the workpiece to be coated.

[0017] A control method for a vacuum coating system capable of precisely controlling film thickness includes the following steps: S1: Divide the coating layer into N sub-coating layers, N≥2, and preset the set thickness distribution of each sub-coating layer; calculate the initial linear motion speed curve of the workpiece carrier corresponding to each sub-coating layer based on the set thickness distribution of each sub-coating layer; wherein, the coating layer is a uniform coating layer or a gradient color coating layer. S2: Turn on the cathode device to perform coating, and at the same time drive the workpiece carrier to move from the first position to the second position at the initial linear motion speed curve corresponding to the first sub-film layer to complete the coating of the first sub-film layer; during the coating process of the first sub-film layer, the film thickness at each position of the workpiece to be coated is detected and recorded in real time, and recorded as the measured thickness distribution. S3: Compare the measured thickness distribution of the first sub-film layer with its set thickness distribution: if the measured thickness at a certain position is greater than the set thickness, decrease the thickness of the second sub-film layer at that position; if the measured thickness at a certain position is less than the set thickness, increase the thickness of the second sub-film layer at that position; based on the comparison results, generate the corrected thickness distribution of the second sub-film layer. S4: Based on the corrected thickness distribution of the second sub-film layer, the corrected linear motion speed curve corresponding to the second sub-film layer is calculated; the drive device drives the workpiece carrier to move from the second position to the first position at the corrected speed curve to complete the coating of the second sub-film layer. S5: Determine the number of sub-film layers N: If N=2, then the coating is considered complete; If N>2, then starting from the third sub-film layer, perform the following steps S51 to S52 sequentially on each sub-film layer until the coating of the Nth sub-film layer is completed: S51: After completing the coating of the previous sub-film layer, detect and record the actual cumulative thickness distribution at each position of the part to be coated; compare the actual cumulative thickness distribution with the theoretical cumulative thickness distribution, which is the sum of the set thickness distributions of all sub-film layers that have been coated; if the actual cumulative thickness at a certain position is greater than the theoretical cumulative thickness, decrease the thickness of the current sub-film layer to be coated at that position; if the actual cumulative thickness at a certain position is less than the theoretical cumulative thickness, increase the thickness of the current sub-film layer to be coated at that position; based on the comparison results, generate the corrected thickness distribution of the current sub-film layer to be coated. S52: Based on the corrected thickness distribution of the current sub-film layer to be coated, the corrected linear motion speed curve corresponding to the current sub-film layer to be coated is calculated; the drive device drives the workpiece carrier to move linearly in the opposite direction to the previous motion direction along the corrected speed curve to complete the coating of the current sub-film layer to be coated.

[0018] As a further improvement to the above control method: In step S1, when dividing the coating layer to be coated into multiple sub-coating layers, a non-uniform division method is adopted, wherein the thickness value at each position in the set thickness distribution of the first sub-coating layer is greater than the set thickness value at the same position in each of the subsequent sub-coating layers.

[0019] Compared with the prior art, the advantages of the present invention are as follows: This invention provides a vacuum coating system with precise film thickness control. A drive device connects to a workpiece carrier, driving it to reciprocate linearly between a first and a second position. This ensures that the workpiece carrier moves from either position, passing through the cathode device and independently completing one coating cycle. This allows for the deposition of multiple sub-layers without changing the operating parameters of the cathode device, enabling continuous operation of the cathode device. Furthermore, by controlling the speed of the workpiece carrier, the dwell time of each region of the workpiece in front of the cathode device can be adjusted, achieving gradual film thickness changes along the direction of movement. This "bidirectional coating" mode enables highly efficient and precise film thickness control, particularly suitable for precision coating processes requiring multiple layering corrections, significantly improving coating efficiency. Moreover, the drive device only needs to drive the workpiece carrier in reciprocating linear motion, resulting in a simple overall structure, low cost, easy control, and stable and reliable operation of the vacuum coating system.

[0020] The control method of this invention decomposes the target film layer into multiple sub-layers and deposits them layer by layer in alternating directions. After each deposition, the thickness distribution of the next sub-layer is compensated and corrected using film thickness detection data, achieving a precise control strategy of "depositing and measuring simultaneously, approximating layer by layer". This method can effectively eliminate film thickness errors caused by factors such as fluctuations in deposition rate, differences in the position of the workpiece to be deposited, and uneven airflow, ensuring that the final film thickness distribution highly matches the design requirements. Since each sub-layer is completed in an independent unidirectional motion with alternating directions, the directional deviation that may accumulate during continuous deposition in the same direction is avoided. In addition, this method allows the cathode device to operate continuously without changing operating parameters, ensuring process stability and improving production efficiency. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural diagram of the vacuum coating system in Example 1.

[0022] Figure 2This is a side cross-sectional view of the vacuum coating system in Example 1.

[0023] Figure 3 for Figure 2 Enlarged structural diagram of section I.

[0024] Figure 4 for Figure 2 Enlarged structural diagram of section II.

[0025] Figure 5 This is a partial cross-sectional view of the joint device in Example 1.

[0026] Figure 6 This is a three-dimensional structural diagram of the driving device in Example 1.

[0027] Figure 7 This is a schematic diagram of the main structure of the vacuum coating system in Example 1 when the workpiece carrier is in the first position.

[0028] Figure 8 This is a schematic diagram of the main structure of the vacuum coating system in Example 1 when the workpiece carrier is in the second position.

[0029] Figure 9 This is a schematic diagram showing the thickness division of a uniformly deposited film layer in Example 2.

[0030] Figure 10 This is a graph showing the initial linear motion speed of a workpiece carrier with a uniformly coated film in Example 2.

[0031] Figure 11 This is a speed curve of a motor with a uniformly coated film layer in Example 2.

[0032] Figure 12 This is a schematic diagram showing the thickness division of a non-uniform gradient color film layer in Example 2.

[0033] Figure 13 This is a graph showing the initial linear motion speed of a workpiece carrier with a non-uniform gradient color film layer in Example 2.

[0034] Figure 14 This is a speed curve of a motor with a non-uniform gradient color film layer in Example 2.

[0035] Figure 15 This is a schematic diagram of the film thickness division in Example 3.

[0036] Figure 16 This is a graph showing the initial linear motion velocity curve of the workpiece carrier in Example 3.

[0037] Figure 17 This is a graph showing the motor speed curve in Example 3.

[0038] Figure 18 This is a schematic diagram of the crank-slider mechanism in a vacuum coating system.

[0039] Legend: 1. Coating chamber; 2. Cathode device; 3. Workpiece carrier; 31. Connecting hole; 4. Drive device; 41. Motor; 42. Drive rod; 43. Driven rod; 44. Slider; 45. Connecting pin; 46. Bearing; 47. Magnetorheological fluid sealing device; 5. Guide device; 51. Permanent magnet guide mechanism; 52. Guide wheel; 6. Joining device; 61. Insertion pin; 62. Cylinder; 7. Baffle plate; 8. Film thickness detection device. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Example 1 like Figure 1 As shown, the vacuum coating system with precise film thickness control in this embodiment includes a coating chamber 1, a cathode device 2, a workpiece carrier 3 for carrying the workpiece to be coated, and a drive device 4 for driving the workpiece carrier 3 to move. The cathode device 2 is installed in the coating chamber 1, and the drive device 4 is connected to the workpiece carrier 3 and can drive the workpiece carrier 3 to reciprocate linearly between a first position and a second position. The workpiece carrier 3 can pass through the cathode device 2 and complete a coating independently during the process of moving from the first position to the second position and from the second position to the first position.

[0042] This vacuum coating system, capable of precisely controlling film thickness, connects to the workpiece carrier 3 via a drive device 4, driving it to reciprocate linearly between a first position and a second position. This ensures that the workpiece carrier 3, whether moving from the first position to the second or vice versa, passes through the cathode device 2 and completes one coating cycle independently. This allows for the deposition of multiple sub-layers without altering the operating parameters of the cathode device 2, enabling continuous operation of the cathode device 2. Furthermore, by controlling the movement speed of the workpiece carrier 3 via the drive device 4, the dwell time of each region of the workpiece before the cathode device 2 can be adjusted, achieving gradual thickness variations along the movement direction. This "bidirectional coating" mode enables highly efficient and precise film thickness control, particularly suitable for precision coating processes requiring multiple layering corrections, significantly improving coating efficiency. Moreover, the drive device 4 only needs to drive the workpiece carrier 3 in reciprocating linear motion, resulting in a simple overall structure, low cost, easy control, and stable and reliable operation of the vacuum coating system.

[0043] In this embodiment, as Figures 2 to 4As shown, the coating chamber 1 is equipped with a guide device 5 for guiding the reciprocating linear motion of the workpiece carrier 3. The guide device 5 constrains and guides the motion trajectory of the workpiece carrier 3, ensuring that it maintains a stable posture during the reciprocating linear motion, avoiding uneven film thickness distribution due to shaking or swaying, while reducing friction and vibration, improving the stability of the coating process, and providing a mechanical basis for high-precision film thickness control.

[0044] In this embodiment, the guiding device 5 includes a permanent magnet guiding mechanism 51 and multiple guide wheels 52. The permanent magnet guiding mechanism 51 is located on top of the workpiece carrier 3 and is used for non-contact levitation positioning and guidance of the reciprocating linear motion of the workpiece carrier 3. The multiple guide wheels 52 are located at the bottom of the workpiece carrier 3 and are arranged sequentially at intervals in the direction of the reciprocating linear motion of the workpiece carrier 3, and are used to support and guide the reciprocating linear motion of the workpiece carrier 3. By combining the non-contact levitation guidance of the top permanent magnet with the support guidance of the bottom guide wheels, a low-friction, high-precision composite guidance is achieved. Among them, the permanent magnet guiding mechanism 51 uses magnetic force to prevent the top of the workpiece carrier 3 from contacting the chamber wall, eliminating top sliding friction and avoiding particulate contamination caused by friction. At the same time, it can automatically center and reduce motion resistance. The multiple guide wheels 52 at the bottom bear the main functions of gravity support and lateral limiting, ensuring smooth movement. This combined structure retains the reliability of contact guidance and introduces the high precision and cleanliness advantages of non-contact guidance. It is particularly suitable for vacuum coating environments, which can significantly extend the system maintenance cycle and improve coating consistency. In this embodiment, the bottom of the workpiece carrier 3 is provided with a guide groove, which is fitted onto the guide wheel 52 to form a guiding fit. The aforementioned permanent magnet guiding mechanism 51 includes two outer permanent magnets installed on the top side wall of the coating chamber 1 and an inner permanent magnet correspondingly connected to the top of the workpiece carrier 3. The inner permanent magnet is located between the two outer permanent magnets and is positioned by magnetic force for non-contact levitation.

[0045] In this embodiment, as Figure 1 and Figure 5 As shown, the drive unit 4 and the workpiece carrier 3 are detachably connected. This detachable connection allows the workpiece carrier 3 to automatically disengage from the drive unit 4 after completing one full coating process (or multiple coating cycles). This allows the drive unit 4 to return to its starting position independently and quickly connect to the next workpiece carrier 3 to be coated, eliminating the need for manual disassembly and reassembly. This improves coating efficiency and is particularly suitable for high-volume, high-cycle industrial coating scenarios. Of course, in other embodiments, the drive unit 4 can also be fixedly connected to the workpiece carrier 3, enabling mass production by replacing the workpieces to be coated on the workpiece carrier 3.

[0046] In this embodiment, as Figure 1 and Figure 6As shown, the driving device 4 includes a motor 41, a driving rod 42, a driven rod 43, and a slider 44. The slider 44 is slidably disposed within the coating chamber 1, and its sliding direction is consistent with the reciprocating linear motion direction of the workpiece carrier 3. The driving rod 42 is fixedly connected to the output shaft of the motor 41 and is driven to rotate by the motor 41. The two ends of the driven rod 43 are respectively hinged to the driving rod 42 and the slider 44. The slider 44 is detachably connected to the workpiece carrier 3 through a connecting device 6. The driving rod 42, the driven rod 43, and the slider 44 constitute a crank-slider mechanism that drives the reciprocating linear motion of the workpiece carrier 3. By using a crank-slider mechanism as a motion conversion component, the continuous rotational motion of the motor 41 can be directly converted into the reciprocating linear motion of the slider 44, eliminating the need for frequent forward and reverse rotation of the motor 41. This improves coating efficiency and avoids the impact, energy consumption, and response delay caused by reverse rotation. Since the motor 41 always rotates in the same direction, its control is simple, its operation is smooth, and it can achieve a high reciprocating frequency. In this embodiment, specifically, one end of the driven rod 43 is hinged to the drive rod 42 via a connecting pin 45, and the other end of the driven rod 43 is hinged to the slider 44 via a bearing 46. The motor 41 is disposed on the outer wall of the coating chamber 1, and the main shaft of the motor 41 is connected to the drive rod 42 via a magnetic fluid sealing device 47, which achieves vacuum sealing.

[0047] In this embodiment, the joining device 6 includes a plug-in pin 61, two cylinders 62, and a joining hole 31 on the workpiece carrier 3. The plug-in pin 61 is mounted on the slider 44 in a reciprocating motion and can be selectively inserted into and removed from the joining hole 31 through reciprocating motion. One cylinder 62 is used to drive the plug-in pin 61 to insert into the joining hole 31 when the workpiece carrier 3 is in the first position, and the other cylinder 62 is used to drive the plug-in pin 61 to remove from the joining hole 31 when the workpiece carrier 3 is in the second position. The joining device 6, through the engagement of the plug-in pin 61 driven by the cylinder 62 and the joining hole 31, can automatically connect the workpiece carrier 3 in the first position and automatically separate it in the second position, realizing the automatic engagement and disengagement of the workpiece carrier 3 and the driving device 4, reducing manual disassembly and assembly operations, facilitating continuous coating production (for example, after one workpiece carrier 3 completes coating separation, the slider 44 returns to the first position to connect the next workpiece carrier 3), and improving the degree of automation and efficiency of production; the two cylinders 62 are responsible for insertion and removal respectively, with reliable operation and avoiding malfunction.

[0048] In this embodiment, the coating chamber 1 is also equipped with two baffle plates 7 respectively disposed on both sides of the cathode device 2. The two baffle plates 7 are located in the space between the cathode device 2 and the workpiece carrier 3. The baffle plates 7 on both sides can effectively limit the spatial distribution range of the coating particles sputtered or evaporated by the cathode device 2, preventing particles from diffusing into non-target areas (such as the side walls of the chamber, the film thickness detection device 8, and other components) and causing stray coating contamination. At the same time, by placing the baffle plates 7 between the cathode device 2 and the workpiece carrier 3, only particles that pass through the opening area between the baffle plates 7 can reach the workpiece to be coated on the workpiece carrier 3, thereby accurately controlling the boundary of the coating area, avoiding edge effects, and improving coating accuracy. In this embodiment, the size of the opening area between the two baffle plates 7 is set so that the workpiece to be coated carried by the workpiece carrier 3 can completely pass through the opening area, whether the workpiece carrier 3 moves from the first position to the second position or from the second position to the first position. The limit position of the slider 44 of the crank-slider mechanism when it is furthest from the crank rotation center is the first position (see Figure 7 The extreme position of slider 44 when it is closest to the crank rotation center is the second position (see...). Figure 8 The first position serves as the entrance position for the workpiece carrier 3 to enter the coating chamber 1, and the second position serves as the exit position for the workpiece carrier 3 to exit the coating chamber 1.

[0049] In this embodiment, a film thickness detection device 8 is installed in the coating chamber 1 for real-time detection of the thickness of the coated layer on the workpiece. By setting up the film thickness detection device 8, the film thickness data at various locations on the workpiece can be detected and acquired in real time during the coating process. This data can be used for thickness correction of subsequent sub-film layers, realizing closed-loop control, thereby significantly improving the accuracy and consistency of the final film thickness while ensuring production efficiency. Preferably, the film thickness detection device 8 and the cathode device 2 are located on the same side wall of the coating chamber 1.

[0050] Example 2 A control method for a vacuum coating system capable of precisely controlling film thickness, as described in Embodiment 1, includes the following steps: S1: Divide the coating layer into N sub-coating layers, N≥2, and preset the set thickness distribution of each sub-coating layer; calculate the initial linear motion speed curve of the workpiece carrier 3 corresponding to each sub-coating layer based on the set thickness distribution of each sub-coating layer; wherein, the coating layer is a uniform coating layer or a gradient color coating layer. S2: The cathode device is turned on to perform coating. At the same time, the drive device 4 drives the workpiece carrier 3 to move from the first position to the second position at the initial linear motion speed curve corresponding to the first sub-film layer, so as to complete the coating of the first sub-film layer. During the coating process of the first sub-film layer, the film thickness at each position of the workpiece to be coated is detected and recorded in real time, and recorded as the measured thickness distribution. S3: Compare the measured thickness distribution of the first sub-film layer with its set thickness distribution: if the measured thickness at a certain position is greater than the set thickness, decrease the thickness of the second sub-film layer at that position; if the measured thickness at a certain position is less than the set thickness, increase the thickness of the second sub-film layer at that position; based on the comparison results, generate the corrected thickness distribution of the second sub-film layer. S4: Based on the corrected thickness distribution of the second sub-film layer, the corrected linear motion speed curve corresponding to the second sub-film layer is calculated; the drive device 4 drives the workpiece carrier 3 to move from the second position to the first position with the corrected speed curve to complete the coating of the second sub-film layer. S5: Determine the number of sub-film layers N: If N=2, then the coating is considered complete; If N>2, then starting from the third sub-film layer, perform the following steps S51 to S52 sequentially on each sub-film layer until the coating of the Nth sub-film layer is completed: S51: After completing the coating of the previous sub-film layer, detect and record the actual cumulative thickness distribution at each position of the part to be coated; compare the actual cumulative thickness distribution with the theoretical cumulative thickness distribution, which is the sum of the set thickness distributions of all sub-film layers that have been coated; if the actual cumulative thickness at a certain position is greater than the theoretical cumulative thickness, decrease the thickness of the current sub-film layer to be coated at that position; if the actual cumulative thickness at a certain position is less than the theoretical cumulative thickness, increase the thickness of the current sub-film layer to be coated at that position; based on the comparison results, generate the corrected thickness distribution of the current sub-film layer to be coated. S52: Based on the corrected thickness distribution of the current sub-film layer to be coated, the corrected linear motion speed curve corresponding to the current sub-film layer to be coated is calculated; the driving device 4 drives the workpiece carrier 3 to move linearly in the opposite direction to the previous motion direction with the corrected speed curve, and completes the coating of the current sub-film layer to be coated.

[0051] This control method divides the target film layer into multiple sub-layers with preset thickness distributions and calculates a speed curve based on these distributions. During the deposition of the first sub-layer, the actual thickness distribution is detected in real time and compared with the set value to correct the thickness distribution of the second sub-layer. This cycle of "detection-comparison-correction-reverse motion deposition" is then repeated for subsequent sub-layers until all sub-layers are completed. By decomposing the target film layer into multiple sub-layers and depositing them layer by layer in alternating directions, and using film thickness detection data to compensate and correct the thickness distribution of the next sub-layer after each deposition, a precise control strategy of "depositing and measuring simultaneously, layer by layer approximation" is achieved. This method effectively eliminates film thickness errors caused by factors such as coating rate fluctuations, differences in the position of the workpiece to be coated, and uneven airflow, ensuring that the final film thickness distribution closely matches the design requirements. Since each sub-layer is completed in an independent unidirectional motion with alternating directions, the directional deviation that may accumulate during continuous deposition in the same direction is avoided. Furthermore, this method allows the cathode device 2 to operate continuously without changing its operating parameters, ensuring process stability and improving production efficiency.

[0052] like Figure 18 As shown, in the control method of this embodiment, the eccentric crank-slider mechanism (i.e., the crank-slider mechanism in the drive device 4) is used, and the slider 44 moves in a horizontal linear motion. It is known that... n The motor speed is 41. r The length of the drive rod is 42. l The length of the driven rod 43 is... h The perpendicular distance between the motor 41 and the workpiece carrier 3 is the distance along their movement trajectory. The angle of rotation of drive lever 42 (i.e., crank) varies over time: The crank angular velocity The linear velocity of slider 44 is derived as follows: Let O be the center of rotation of the drive rod 42, A be the hinge point between the drive rod 42 and the driven rod 43 (i.e., the crank end point), and denot the hinge point between the driven rod 43 and the slider 44 as... B Establish a coordinate system with the rotation center O of the drive rod 42 as the origin and the horizontal direction as the x-axis. The slider 44 guides a horizontal straight line, and its equation is: y=-h .

[0053] The coordinates of crank end point A are: .

[0054] The hinge point between the driven rod 43 and the slider 44 B Coordinates are ( ,﹣ h ), The X-axis coordinate value of hinge point B is given by the length of driven rod 43. l constraint:

[0055] The displacement of slider 44 is obtained (taking a common assembly position):

[0056] right Differentiate, The velocity of slider 44 is obtained:

[0057] Summarized as follows:

[0058] Introducing the angle between the driven rod 43 and the horizontal line ,satisfy:

[0059] The velocity formula can be simplified to:

[0060] in (The value must be chosen to ensure the continuous movement of the mechanism).

[0061] The final formula for calculating the motion speed of workpiece carrier 3 is as follows: v h = v s =

[0062] In the formula, v h The speed of the workpiece carrier 3 is the movement speed. v s The speed of slider 44.

[0063] The motor speed can be calculated from the above speed formula:

[0064] The formula for calculating the motor speed is as follows:

[0065] In the formula, Let be a geometric function, and assume a constant deposition rate.

[0066] The calculation yields the limit position E of the crank-slider mechanism corresponding to the inlet position of the vacuum coating system. =330°), the exit position corresponds to the extreme position F of the crank-slider mechanism ( =108°).

[0067] The control method of the vacuum coating system with precise film thickness control in this embodiment is applicable to both uniform film layers and non-uniform gradient color film layers. For uniform film layers, in one specific embodiment, the film layer to be coated can be uniformly divided into three sub-film layers (see...). Figure 9 The initial linear motion velocity curve of the workpiece carrier 3 (slider 44) corresponding to each sub-film layer was calculated (see...). Figure 10 And based on the motion speed curve of the workpiece carrier 3, the speed curve of the motor 41 corresponding to each sub-film layer is calculated (see...). Figure 11 ).

[0068] For non-uniform gradient color films, in one specific embodiment, the gradient color appearance requirement can be input into the program to obtain the film thickness at each location of the part to be coated, and then divided into three sub-film layers (see...). Figure 12 The initial linear motion velocity curve of the workpiece carrier 3 (slider 44) corresponding to each sub-film layer was calculated (see...). Figure 13 And based on the motion speed curve of the workpiece carrier 3, the speed curve of the motor 41 corresponding to each sub-film layer is calculated (see...). Figure 14 ).

[0069] Example 3 The control method of the vacuum coating system with precise film thickness control in this embodiment is basically the same as that in Embodiment 2. The main difference is that when dividing the film to be coated into multiple sub-film layers in step S1, a non-uniform division method is adopted. The thickness value at each position in the set thickness distribution of the first sub-film layer is greater than the set thickness value at the same position in each of the subsequent sub-film layers. By concentrating the main thickness share of the film to be coated in the first sub-film layer, the number of subsequent sub-film layers can be reduced and only a small correction amount is required, which can significantly reduce the total number of coating cycles.

[0070] In this embodiment, the film to be coated is specifically divided into three sub-film layers. The first sub-film layer has a larger thickness, while the thickness values ​​of the second and third sub-film layers at each location are smaller than the thickness value of the first sub-film layer at the same location (see [reference]). Figure 15 The initial linear motion velocity curve of the workpiece carrier 3 (slider 44) corresponding to each sub-film layer was calculated, see [reference]. Figure 16 The speed curve of motor 41 corresponding to each sub-film layer was calculated based on the motion speed curve of workpiece carrier 3. See [reference needed]. Figure 17 .

[0071] The above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and modifications obtained without departing from the inventive concept should also be considered within the scope of protection of the present invention.

Claims

1. A control method for a vacuum coating system capable of precisely controlling film thickness, the vacuum coating system comprising a coating chamber (1), a cathode device (2), a workpiece carrier (3) for supporting the workpiece to be coated, and a drive device (4) for driving the workpiece carrier (3) to move, wherein the cathode device (2) is installed inside the coating chamber (1), characterized in that: The driving device (4) is connected to the workpiece carrier (3) and can drive the workpiece carrier (3) to reciprocate linearly between the first position and the second position. The workpiece carrier (3) can pass through the cathode device (2) and complete a coating independently during the process of moving from the first position to the second position and from the second position to the first position. The control method includes the following steps: S1: Divide the coating layer into N sub-coating layers, N≥2, and preset the set thickness distribution of each sub-coating layer; calculate the initial linear motion speed curve of the workpiece carrier (3) corresponding to each sub-coating layer based on the set thickness distribution of each sub-coating layer; wherein, the coating layer is a uniform coating layer or a gradient color coating layer. S2: Turn on the cathode device to perform coating, and at the same time drive the drive device (4) to drive the workpiece carrier (3) to move from the first position to the second position with the initial linear motion speed curve corresponding to the first sub-film layer, and complete the coating of the first sub-film layer; during the coating process of the first sub-film layer, the film thickness at each position of the workpiece to be coated is detected and recorded in real time, and recorded as the measured thickness distribution. S3: Compare the measured thickness distribution of the first sub-film layer with its set thickness distribution: if the measured thickness at a certain position is greater than the set thickness, decrease the thickness of the second sub-film layer at that position; if the measured thickness at a certain position is less than the set thickness, increase the thickness of the second sub-film layer at that position; based on the comparison results, generate the corrected thickness distribution of the second sub-film layer. S4: Based on the corrected thickness distribution of the second sub-film layer, the corrected linear motion speed curve corresponding to the second sub-film layer is calculated; the driving device (4) drives the workpiece carrier (3) to move from the second position to the first position with the corrected speed curve to complete the coating of the second sub-film layer. S5: Determine the number of sub-film layers N: If N=2, then the coating is considered complete; If N>2, then starting from the third sub-film layer, perform the following steps S51 to S52 sequentially on each sub-film layer until the coating of the Nth sub-film layer is completed: S51: After completing the coating of the previous sub-film layer, detect and record the actual cumulative thickness distribution at each position of the part to be coated; compare the actual cumulative thickness distribution with the theoretical cumulative thickness distribution, which is the sum of the set thickness distributions of all sub-film layers that have been coated; if the actual cumulative thickness at a certain position is greater than the theoretical cumulative thickness, decrease the thickness of the current sub-film layer to be coated at that position; if the actual cumulative thickness at a certain position is less than the theoretical cumulative thickness, increase the thickness of the current sub-film layer to be coated at that position; based on the comparison results, generate the corrected thickness distribution of the current sub-film layer to be coated. S52: Based on the corrected thickness distribution of the current sub-film layer to be coated, the corrected linear motion speed curve corresponding to the current sub-film layer to be coated is calculated; the driving device (4) drives the workpiece carrier (3) to move in a straight line in the opposite direction to the previous motion direction with the corrected speed curve, and completes the coating of the current sub-film layer to be coated.

2. The control method for the vacuum coating system with precisely controllable film thickness according to claim 1, characterized in that: The coating chamber (1) is provided with a guide device (5) for guiding the reciprocating linear motion of the workpiece carrier (3).

3. The control method for the vacuum coating system with precisely controllable film thickness according to claim 2, characterized in that: The guiding device (5) includes a permanent magnet guiding mechanism (51) and multiple guide wheels (52). The permanent magnet guiding mechanism (51) is set on the top of the workpiece carrier (3) and is used to perform non-contact suspension positioning and guidance for the reciprocating linear motion of the workpiece carrier (3). The multiple guide wheels (52) are set at the bottom of the workpiece carrier (3) and are arranged sequentially at intervals in the reciprocating linear motion direction of the workpiece carrier (3) to support and guide the reciprocating linear motion of the workpiece carrier (3).

4. The control method for the vacuum coating system with precisely controllable film thickness according to claim 1, characterized in that: The drive device (4) is detachably connected to the workpiece carrier (3).

5. The control method for the vacuum coating system with precisely controllable film thickness according to claim 4, characterized in that: The driving device (4) includes a motor (41), a driving rod (42), a driven rod (43), and a slider (44). The slider (44) is slidably disposed in the coating chamber (1) and the sliding direction is consistent with the reciprocating linear motion direction of the workpiece carrier (3). The driving rod (42) is fixedly connected to the output shaft of the motor (41) and is driven to rotate by the motor (41). The two ends of the driven rod (43) are respectively hinged to the driving rod (42) and the slider (44). The slider (44) is connected to the workpiece carrier (3) in a separable manner through the coupling device (6). The driving rod (42), the driven rod (43), and the slider (44) constitute a crank-slider mechanism for driving the reciprocating linear motion of the workpiece carrier (3).

6. The control method for the vacuum coating system with precisely controllable film thickness according to claim 5, characterized in that: The engagement device (6) includes a plug pin (61), two cylinders (62), and an engagement hole (31) provided on the workpiece carrier (3). The plug pin (61) is mounted on the slider (44) in a reciprocating motion and can be selectively inserted into and removed from the engagement hole (31) by reciprocating motion. One cylinder (62) is used to drive the plug pin (61) to insert into the engagement hole (31) when the workpiece carrier (3) is in the first position, and the other cylinder (62) is used to drive the plug pin (61) to remove from the engagement hole (31) when the workpiece carrier (3) is in the second position.

7. The control method for the vacuum coating system with precisely controllable film thickness according to claim 1, characterized in that: The coating chamber (1) is also equipped with two shielding plates (7) located on both sides of the cathode device (2), and the two shielding plates (7) are located in the space between the cathode device (2) and the workpiece carrier (3).

8. The control method for the vacuum coating system with precisely controllable film thickness according to claim 1, characterized in that: The coating chamber (1) is equipped with a film thickness detection device (8) for real-time detection of the thickness of the coated layer on the workpiece to be coated.

9. The control method for the vacuum coating system with precisely controllable film thickness according to claim 1, characterized in that: In step S1, when dividing the coating layer to be coated into multiple sub-coating layers, a non-uniform division method is adopted, wherein the thickness value at each position in the set thickness distribution of the first sub-coating layer is greater than the set thickness value at the same position in each of the subsequent sub-coating layers.

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