Device and method for monitoring a coating process involving at least one coating process

Abstract

In a device and a method for monitoring a coating process comprising at least one coating step, a rotary disk (118) is rotatably mounted in a carrier plate (112) and is designed with an analysis recess (121). The rotary disk (118) has a toothed structure (293) along its circumference, which, via a rocker arm mechanism (242) controlled by an electromechanical drive (275), serves to rotate the rotary disk (118) at times detected by sensors (245, 248, 251) and implemented by control electronics (236). This allows a coating process of a substrate, for example in the form of a flat glass plate, which is composed of several coating steps, to be documented and monitored with relative accuracy.

Description

[0001] The invention relates to a device for monitoring a coating process comprising at least one coating operation according to the preamble of claim 1.

[0002] The invention further relates to a method for monitoring a coating process comprising at least one coating operation according to the preamble of claim 13.

[0003] Such a device and such a method for monitoring a coating process comprising at least one coating operation are known from DE 10 2017 118 609 A1. In the previously known device and the previously known method, a carrier plate is provided which has a central clearance formed by a circular recess and a number of receiving spaces arranged around the central clearance. The device further comprises a turntable which is rotatably mounted in the central clearance of the carrier plate and which has at least one analysis recess. Furthermore, the previously known device is equipped with a drive with which the turntable can be driven to rotate in at least one direction of rotation, and has a trigger unit for controlling the drive.This allows the layer or layers applied during each coating process to be examined, for example for the purposes of process control or quality assurance, by successively rotating the turntable, particularly after the entire coating process has been carried out.

[0004] The invention is based on the object of specifying a device and a method of the type mentioned at the outset with which a coating process comprising at least one coating operation can be monitored very precisely in situ.

[0005] This object is achieved according to the invention in a device of the type mentioned at the outset with the characterizing features of claim 1.

[0006] This object is achieved in a method for monitoring a coating process comprising at least one coating operation with the characterizing features of claim 13.

[0007] Because in the device and method according to the invention the trigger unit can be controlled via control electronics comprising a sensor unit, and the sensor unit delivers measurement signals that are characteristic of a coating process and can also be linked to one another, the turntable with the analysis recess can be moved very precisely, for example, at the beginning or end of a coating process. This allows the layer or layers deposited during a coating process to be examined very precisely as part of an evaluation, particularly for the purposes of process control and quality monitoring, since it is ensured that the deposition of the layer or layers in the area of ​​a substrate lying beneath the analysis recess is / are very precisely synchronized with the respective coating process.

[0008] Further expedient embodiments of the invention are the subject of the dependent claims.

[0009] Further expedient embodiments and advantages of the invention will become apparent from the following description of an embodiment of the invention with reference to the figures of the drawing.

[0010] They show: Fig. 1 shows in a perspective view an embodiment of a device according to the invention, which is placed in a corner area of ​​a flat glass plate as a substrate, with a view of a cover plate placed on a carrier plate, Fig. 2 in a perspective view the embodiment according to Fig. 1 with the cover plate removed, showing a rotating disk formed with a toothed structure and further components arranged in receiving spaces, Fig. 3 in a perspective view of the carrier plate of the embodiment according to Fig. 1 and Fig. 2 with a turntable bearing ring surrounding a central clearance, Fig. 4 in a block diagram essential electrical and electromechanical elements of the embodiment according to Fig. 1 and Fig. 2 , Fig. 5 in an exemplary diagram the time course of measurement signals formed by incident electromagnetic radiation in the visible or ultraviolet spectral range when carrying out an example of a method according to the invention with approximately constant maximum intensities, Fig. 6 in an exemplary diagram the time course of measurement signals formed by incident electromagnetic radiation in the visible or ultraviolet spectral range when carrying out an example of a method according to the invention with changing maximum intensities and Fig. 7 in a block diagram essential electronic and electromechanical elements of a further development of the embodiment according to Fig. 4 .

[0011] Fig. 1 shows a perspective view of a corner region 103 of a flat glass plate 106 as a substrate for a coating process preferably comprising multiple coating operations. As an embodiment of a device according to the invention, a measuring device 109 is placed in the corner region 103 of the flat glass plate 106 and is expediently releasably and firmly connected to the flat glass plate 106 by means of a very thin adhesive tape that is resistant to a coating process to which the flat glass plate 106 is subjected. As a result, the measuring device 109 remains in place on the flat glass plate 106 during the coating process for in-situ monitoring of a coating process.

[0012] The measuring device 109 has a cuboid shape with a rectangular base and a very low height of a few millimeters to typically at most about 10 millimeters compared to the side edges of the base in order to maintain or fall below the maximum throughput height of deposition devices used in the coating process for layers to be applied to the flat glass plate 106.

[0013] The measuring device 109 has as essential, in Fig. 1 visible mechanical components via a carrier plate 112 with a relatively large, circular central clearance 115 as a recess for reasons of weight saving, in which a round, for reasons of weight saving, relatively small-area annular shaped turntable 118 is arranged, which is rotatable relative to the carrier plate 112. The turntable 118 is formed with an analysis recess 121, which, depending on the rotational position of the turntable 118, exposes a defined analysis coating area of ​​the flat glass plate 106. In the Fig. 1 In the embodiment shown, the dimensions of the analysis recess 121 are approximately the same in the radial direction and in the circumferential direction.

[0014] Furthermore, the measuring device 109 is equipped with a cover plate 124, which covers the support plate 112 except for the central cutout 115 on the upper side facing away from the flat glass plate 106. The cover plate 124 is detachably connected to the support plate 112 via a number of screw connections 127.

[0015] Furthermore, sensor recesses 130, 133 are formed in the cover plate 124, the purpose of which is explained in more detail below.

[0016] Fig. 2 shows in a perspective view the Fig. 1 explained measuring device 109 with removed and in Fig. 2 Cover plate 124 (not shown) with a view of the upper side facing away from a substrate, for example, in the form of a flat glass plate 106, during intended use of the measuring device 109. The carrier plate 112 has a number of receiving spaces 203, 206, 209, 212 closed at the bottom, which are formed in corner regions of the carrier plate 112 around the central clearance 115. Cable ducts 215, 218, 221 extend between the receiving spaces 203, 206, 209, 212. In two receiving spaces 203, 206 formed on a long side, a battery 224, 227 is arranged as a rechargeable storage for electrical energy, which are connected via electrical lines 230, 233 located in cable ducts 215, 218 to a control electronics 236 also arranged in a receiving space 209 and, among other things, supply this with electrical energy.

[0017] In a further receiving space 212, in turn, there is a drive for rotating the turntable 118 by one rotational step over a certain angular range, which in the embodiment according to Fig. 1 expediently somewhat larger than the extent of the analysis recess 121 in the circumferential direction, an electromechanical rocker arm mechanism 242 is arranged, which can be controlled or supplied with electrical energy via an electrical line 239 lying in a cable duct 221 with the control electronics 236 and via this with the batteries 224, 227.

[0018] The control electronics 236 is equipped with a sensor unit that has a radiation sensor 245 for electromagnetic radiation, which is positioned on the control electronics 236 in the region of a sensor recess 130 formed in the cover plate 124. The radiation sensor 245 can detect electromagnetic radiation from the ultraviolet to near-infrared spectral range applied to a substrate such as a flat glass plate 106, particularly during coating processes of a coating process, in the form of measurement signals.Furthermore, the sensor unit of the control electronics 236 has a temperature sensor 248 arranged in the area of ​​the other sensor recess 133 and sensitive to longer-wave radiation in the near to far infrared spectral range for detecting the temperature of the environment of the measuring device 109 as a further measurement signal and an acceleration sensor 251 for detecting the accelerations acting on the measuring device 109 as a further measurement signal over time.

[0019] The control electronics 236 having a processor 254 is further equipped with a removable data memory 257, with a read-only memory 260 and with a program memory 263, wherein during a coating process the measurement signals can be stored in the removable data memory 257 and in the read-only memory 260 in their temporal course, while a program controlling the processor 254 is stored in the program memory 263 for access.

[0020] To access the read-only memory 260 and the program memory 263, wired interfaces 266 for data exchange and for charging the batteries 224, 227 and a wireless interface 269 for data exchange are integrated in the control electronics 236.

[0021] The electromechanical rocker arm mechanism 242, which is connected via a line distributor 272 to the electrical line 239 connected to the control electronics 236, is equipped with an electromagnetically operating drive 275, with which a pivoting lever 287 can be articulated via an intermediate lever 284 extending in the direction of the turntable 118 and arranged between two stop lugs 278, 281, which in the illustration according to Fig. 2 via a locking tooth 290 with a tooth structure 293 formed circumferentially on the rotary disk 118. The pivot lever 287 is held in engagement with the tooth structure 293 by a return spring 296 as a return when the rocker arm mechanism 242 is not actuated.

[0022] Fig. 3 shows in a perspective view the carrier plate 112 without the in the according to the description to Fig. 2 components installed in the carrier plate 112 in the case of Fig. 1 and Fig. 2 explained measuring device 109 as an embodiment of a device according to the invention. Fig. 3 It can be seen that the stop lugs 278, 281 are opposite each other and that there is a space between them to accommodate the Fig. 3 not shown intermediate lever 284. Between the stop lugs 278, 281, there is a hinge pin 303 on which the intermediate lever 284 is rotatably mounted. When the intermediate lever 284 is actuated by means of the drive 275, the stop lugs 278, 281 act on the intermediate lever 284 in such a way that the locking tooth 290, via the tooth structure 293, causes the turntable 118 and thus the analysis recess 121 to rotate in one direction.

[0023] Furthermore, according to the illustration Fig. 3 It can be seen that a turntable bearing ring 306 as a turntable bearing made of a low-friction, chemically and thermally resistant plastic material surrounds the central clearance 115 of the carrier plate 112, so that the turntable 118 is mounted with low friction.

[0024] Fig. 4 shows in a block diagram essential electrical, electronic and electromechanical components of the measuring device 109 as an embodiment of a device according to the invention, which are partly integrated in the control electronics 236 and partly already in particular in connection with Fig. 2 have been explained. From Fig. 4 It can be seen that the radiation sensor 245, the temperature sensor 248, the acceleration sensor 251, as well as the removable data storage 257 and the read-only memory 260 are connected to the processor 254. Furthermore, the wired interfaces 266, the wireless interface 269, and the rechargeable batteries 224, 227 with a charging circuit 403, which also supply the interfaces 266, 269 with electrical energy, are connected to the processor 254. A driver stage 406 of a trigger unit is also connected to the processor 254, which can also be supplied with electrical energy via the rechargeable batteries 224, 227 and with which the electromechanical drive 275 of the rocker arm mechanism 242 can be controlled as an actuator.

[0025] Furthermore, Fig. 4 an external data processing unit 409 is shown, which can be connected to the processor 254 via the interfaces 266, 269 in order to feed control software for the processor 254, to read the removable data memory 257 and the read-only memory 260 and to parameterize the measuring device 109.

[0026] The processor 254 is configured to write the measurement signals characteristic of the or each coating process of a coating process, which are supplied by the radiation sensor 245, the temperature sensor 248 and / or the acceleration sensor 251, into the removable data memory 257 and / or the read-only memory 260 and to process them in such a way that the turntable 118 is driven to rotate by one rotation step before or after a coating process by controlling the electromechanical drive 275 via the driver stage 406.

[0027] Fig. 5 shows in a diagram the course of a measurement signal 503 plotted against time t during a run through two typical coating operations of a coating process. In the measurement signal 503 according to Fig. 5 This is the output signal of the radiation sensor 245, which detects relatively high-energy visible or ultraviolet radiation in its respective intensity.

[0028] Out of Fig. 5 It can be seen that in a coating process in which a radiation source emitting in the visible or ultraviolet spectral range is used, the measurement signal 503 has a single maximum between a time t1 at the beginning of a rising edge and a time t2 at the end of a falling edge, while between a time t3, which is at the beginning of a rising edge, and a time t4, which is at the end of a falling edge, the measurement signal 503 has two maxima during the associated coating process.It is thus evident that with the measurement signal 503 of the radiation sensor 245, on the one hand, the intensity profile of radiation characteristic of the respective coating process can be detected, but also the coating processes with their respective typical intensity profiles of detected radiation can be distinguished from one another and thus assigned to specific positions of a substrate when passing through a coating process.

[0029] According to the illustration Fig. 5 It can also be seen that the times t1, t2, t3, t4 can basically be used to control the electromechanical drive 275, since they are each characteristic for a coating process.

[0030] Expediently, the driver stage 406 is activated at times t1, t3 at the beginning of a rising edge with a higher signal level l2 of the measurement signal 503, while at times t2, t4 at the end of a falling edge with a lower signal level l1, the rotary disk 118 is rotated to its next position. This achieves a switching hysteresis and ensures that the analysis recess 121 is in its new position at the beginning of a new coating process. In the event that, for example, due to a defect in the sensor unit, no measurement signal 503 usable for switching is available, provision is made for switching to occur as part of an emergency procedure according to a predetermined fixed schedule adapted to the expected temporal progression of the coating process.

[0031] The measurement signals advantageously provided by several sensors of different types, such as the radiation sensor 245, the temperature sensor 248 and the acceleration sensor 251 in the exemplary embodiment explained, are expediently linked to one another in such a way that the sum of the measurement signals reflects the totality of the events occurring during a coating process.

[0032] For example, the measurement signals of the acceleration sensor 251 can be evaluated in such a way that typical accelerated movements of the substrate, for example at the beginning and end of a coating process, are evaluated in order to switch the device according to the invention on and off, while the measurement signals supplied by the radiation sensor 245 and / or the temperature sensor 248 trigger the step-by-step rotation of the turntable 118.

[0033] A further function of the acceleration sensor 251 is expediently to monitor the synchronization of the conveyor device moving the substrate and to trigger a warning in the event of deviations, for example due to worn rollers as transport elements.

[0034] In the case of a modification of the Fig. 1 and Fig. 2 In the exemplary embodiment explained, the rotary disk 118 is formed with an analysis recess 121 extending in the circumferential direction over a larger angular range encompassing several rotation steps of the rotary disk 118. This allows stacks of layers, each in a different sequence, to be analyzed in the region of the circular-arc-shaped analysis recess 121 over several coating processes.

[0035] In a further modification, it is provided to suppress at least one rotation step of the rotary disk 118 and leave the analysis recess 121 stationary during at least two coating processes. This allows a stack of two or more layers to be built up and filtered out accordingly.

[0036] Fig. 6 shows in a diagram the course of a measurement signal 503 corresponding to an intensity I, plotted against time t, when passing through two typical coating processes of a coating process with, compared to the diagram according to Fig. 5 declining maximum intensities, which are caused, for example, by a gradually building up radiation-absorbing coating on a radiation sensor 245. In order to continue to be able to reliably carry out, for example, process control and quality monitoring under these circumstances, it is provided that the control electronics 236 is equipped with a switching threshold adjustment module with which the switching thresholds can be adjusted, as explained in more detail below by way of example.

[0037] The switching threshold adjustment module can be used to activate the driver stage 406 at a time t1 at which a first activation switching threshold lact1, which is higher than a typical lowest minimum intensity Imin1-2 by a predetermined ratio and thus on a rising edge, has been exceeded. Subsequently, a first local intensity maximum Imax1 can be determined at time t2 using the switching threshold adjustment module, and a first feed switching threshold Ifwd1 can be determined in advance on the falling edge for further switching relative to the intensity maximum Imax1. After the first feed switching threshold Ifwd1 is undershot at time t3, a signal for rotating by one rotation step is generated.

[0038] Subsequently, at a time t4 at which a predetermined second activation switching threshold lact2, which lies above a typical lowest minimum intensity Imin1-2 with a ratio predetermined by the previous local intensity maximum Imax1 and thus on a rising edge, the driver stage 406 can be activated again. Subsequently, a second local intensity maximum Imax2 can be determined at time t5 using the switching threshold adjustment module, and a second advance switching threshold on the falling edge can be determined in advance relative to the second intensity maximum Imax2.

[0039] In this example, however, the switching threshold adjustment module can determine that, due to the presence of a double cathode at this point, a local minimum Imin3 was passed through before the precalculated second feed switching threshold was undershot at time t6, so that the second feed switching threshold will no longer be undershot. Rather, a signal for rotating by one rotation step is generated, and a third activation switching threshold lact3 is determined in advance, taking into account the previous local intensity maximum Imax2 and the previous local intensity minimum Imin3. After the third activation switching threshold lact3 is exceeded at time t7, the driver stage 406 can be reactivated.

[0040] Subsequently, the switching threshold adjustment module can be used to determine a third local intensity maximum Imax3 at time t8 and, relative to the third intensity maximum Imax3, a third feed switching threshold Ifwd3 on the falling edge. After the third feed switching threshold Ifwd3 is undershot at time t9, a signal for rotation by one rotation step is generated again.

[0041] In this way, the individual intensities generated by a double cathode with corresponding coating processes can also be analyzed separately.

[0042] Fig. 7 shows in a block diagram a further development of the Fig. 4 In the further development according to Fig. 7 A sound sensor 703 is provided, for example in the form of a structure-borne sound sensor or a microphone, which is connected to the processor 254 via a converter stage 706. Furthermore, the development according to Fig. 7 equipped with a counter 709 with which the forwardings can be counted.

[0043] With the further training according to Fig. 7 It is possible to record the characteristic sound signals, for example, when a substrate surface is scratched by deposits on transport rollers. Using the counter reading and the elapsed time, it is possible to determine the position of the material causing the scratch within the coating system. This allows for efficient repair of the coating system if necessary.

Claims

1. Device for monitoring a coating process comprising at least one coating operation, with a carrier plate (112) which has a central clearance (115) and receiving spaces (203, 206, 209, 212), with a turntable (118) which is rotatably mounted in the central clearance (115) of the carrier plate (112) and which has at least one analysis recess (121), with a drive (275) with which the turntable (118) can be driven to rotate in at least one direction of rotation, and with a trigger unit (406) for controlling the drive (275), characterized in that there is a cover plate (124) which can be detachably connected to the carrier plate (112) and which has at least one sensor recess (130, 133), that there is control electronics (236) comprising the trigger unit (406) and which is arranged in a receiving space (209). and which has a sensor unit (245, 248, 251) with which the trigger unit (406) can be controlled at specific times (t1, t2, t3, t4, t7, t9) of the coating process depending on measurement signals (503) characteristic of a coating process and detected by the sensor unit (245, 248, 251).

2. Device according to claim 1, characterized in that the sensor unit comprises at least one radiation sensor (245) which is sensitive to relatively short-wave electromagnetic radiation generated during a coating process for carrying out a coating operation.

3. Device according to claim 2, characterized in that the sensor unit comprises at least one temperature sensor (248) which is sensitive to temperatures prevailing in the region of the device during a coating process.

4. Device according to claim 2 or claim 3, characterized in that the sensor unit has at least one acceleration sensor (251) which is sensitive to accelerations occurring during a coating process.

5. Device according to one of claims 1 to 4, characterized in that a sound sensor (703) and a counter (709) are provided for locating coating processes causing scratches.

6. Device according to one of claims 1 to 5, characterized in that the control electronics (236) have an interface for a removable data storage device (257) on which time-resolved measurement signals can be stored.

7. Device according to one of claims 1 to 6, characterized in that the control electronics (236) have at least one memory (260) on which measurement signals can be stored in a time-resolved manner, and an interface (266, 269) for reading out the memory (260).

8. Device according to one of claims 1 to 7, characterized in that the control electronics (236) have a program memory (263) and an interface (266, 269) for accessing the program memory (263).

9. Device according to one of claims 1 to 8, characterized in that at least one energy storage device (224, 227) for electrical energy is present, which is arranged in a receiving space (203, 206).

10. Device according to one of claims 1 to 9, characterized in that the drive (275) is a component of an electromechanical rocker arm mechanism (242) which can be brought into engagement with a tooth structure (293) formed along the circumference of the turntable (118) for rotating the turntable (118).

11. Device according to claim 10, characterized in that the rocker arm mechanism (242) is equipped with a pivot lever (287) operable in one direction for actively driving the turntable (118) in one direction of rotation and with a spring-assisted retraction (296) for transferring the pivot lever (287) into a rest position.

12. Device according to one of claims 1 to 11, characterized in that a low-friction turntable bearing (306) is arranged between the carrier plate (112) and the turntable (118).

13. Method for monitoring a coating process comprising at least one coating operation, comprising the steps - Providing a substrate, arranging a device having the features of the preamble of claim 1 on the substrate, removing the device from the substrate and analyzing a coated area or areas which were each left free from the analysis recess (121) during a coating process, characterized by the steps - Providing a device having the characterizing features of one of claims 1 to 12 and Carrying out a coating process with detection of measurement signals by the sensor unit (245, 248, 251) and controlling the trigger unit (406) at specific times (t1, t2, t3, t4, t7, t9) by rotating the turntable (118).

14. Method according to claim 13, characterized in that the turntable (118) is rotated at a time (t2, t3, t4, t6) at the end of a falling edge of a measurement signal (503).

15. Method according to claim 13 or claim 14, characterized in that the times (t2, t3, t4, t6) are determined as a function of the maximum intensity (Imax1, Imax2) of a coating process.

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