Optical film thickness monitoring device and optical film coating system

Abstract

The invention discloses an optical thin film thickness monitoring device and an optical thin film coating system, and belongs to the technical field of vacuum coating. A workpiece disc of the optical film thickness monitoring device is provided with a monitoring hole group, the monitoring hole group comprises a first through hole, a second through hole and an interval shielding area, and a film coating monitoring piece is arranged in the first through hole; the irradiation light source is used for emitting light signals to the monitoring hole group; the receiving assembly comprises a light converging element and at least two grating monochromators. The actual physical or optical thickness of the thin film can be calculated by monitoring the transmission or reflectivity of multiple wavelengths and combining the dispersion of the material, and the precision is higher than the precision of monitoring the thickness of the single-wavelength thin film. A plurality of grating monochromaters respectively and correspondingly monitor one wavelength, each grating monochromator can freely select the wavelength, the wavelength selection range is wide, and the problems that the monitoring wavelength is changed and the positioning precision deviation is large in the same grating monochromator are solved. According to the invention, the optical film thickness measurement precision in the online monitoring film coating process can be improved, and the film coating success rate is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of vacuum coating, and relates to the technology of online monitoring of the thickness of an optical thin film during the coating process, and particularly relates to a novel optical thin film thickness monitoring device and an optical thin film coating system. Background Art

[0002] In the technical field of vacuum coating, it is generally necessary to online monitor the thickness of an optical thin film during the coating process, and the thickness measurement accuracy is crucial for improving the coating success rate.

[0003] Most of the existing technologies are single-wavelength monitoring, which cannot meet the monitoring requirements of complex film systems, resulting in insufficient monitoring accuracy for some film layers, large physical thickness deviations of the formed thin film, and ultimately coating failure. Theoretically, the monitoring accuracy can be improved by continuously changing the monitoring wavelength. However, due to the positioning accuracy and repeated positioning accuracy deviations of the grating monochromator wavelength, changing the monitoring wavelength will cause a difference between the theoretical wavelength and the actual wavelength, resulting in different phases of the already coated film system for the actual wavelength and the theoretically calculated phase, causing calculation chaos and instead reducing the monitoring accuracy. Based on this, the present invention proposes a novel technology for online monitoring of the thickness of an optical thin film during the coating process to overcome the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a novel optical thin film thickness monitoring device and an optical thin film coating system to solve the problem that the existing single-wavelength monitoring accuracy is insufficient, and changing the monitoring wavelength still results in insufficient monitoring accuracy due to the repeated positioning accuracy deviation of the grating monochromator.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] The present invention provides an optical thin film thickness monitoring device, including:

[0007] A workpiece disk, which is used to be installed in a vacuum coating machine and is rotationally drivenly connected to the vacuum coating machine. The workpiece disk is used to place an optical thin film; a monitoring hole group is formed on the workpiece disk. The monitoring hole group includes a through hole one, a through hole two, and an interval shielding area located between the through hole one and the through hole two. The through hole one and the through hole two are located on the same circumference, and a coating monitoring piece is arranged in one of the through hole one and the through hole two;

[0008] An irradiation light source, which is used to be installed in the vacuum coating machine and is located below the workpiece disk. The irradiation light source is used to emit an optical signal to the monitoring hole group;

[0009] A receiving component, comprising a light converging element and at least two grating monochromators. The light converging element is used to be installed on the vacuum coating machine. Each grating monochromator is connected to the output end of the light converging element through an optical fiber. The light converging element is used to receive the optical signal passing through the monitoring hole group and simultaneously transmit the optical signal to each grating monochromator. An optoelectronic detector is connected to the output end of any one of the grating monochromators. The optoelectronic detector can convert the quasi-monochromatic light λ selected by the corresponding grating monochromator into a corresponding electrical signal S and output it.

[0010] Preferably, the optical thin film thickness monitoring device further comprises a control terminal. The output end of any one of the optoelectronic detectors is communicatively connected to the control terminal.

[0011] Preferably, the optical thin film thickness monitoring device further comprises an analog-to-digital converter. The output end of any one of the optoelectronic detectors is communicatively connected to the control terminal through the analog-to-digital converter.

[0012] Preferably, the output end of the light converging element is connected to at least two grating monochromators through a bifurcated optical fiber. Wherein, the bifurcated optical fiber comprises a main optical fiber and at least two branch optical fibers. One end of the main optical fiber is connected to the output end of the light converging element, and all the branch optical fibers are connected to the other end of the main optical fiber. The branch optical fibers are connected to the grating monochromators in a one-to-one correspondence, and at least two branch optical fibers are simultaneously connected to the grating monochromators.

[0013] Preferably, the bifurcated optical fiber is a Y-shaped optical fiber including two branch optical fibers.

[0014] Preferably, the cross-section of the optical fiber core bundle in the main optical fiber is circular; the cross-section of the optical fiber core bundle in any one of the branch optical fibers is strip-shaped.

[0015] Preferably, the lengths of the arc lengths occupied by the first through hole, the second through hole, and the spaced shielding area on the circumference are the same.

[0016] Preferably, the irradiation light source is a white light source, and the light converging element is a converging lens.

[0017] The present invention also provides an optical thin film coating system, comprising a vacuum coating machine and the optical thin film thickness monitoring device according to any one of the above. The workpiece disk is installed in the vacuum coating machine and is rotationally drivenly connected to the vacuum coating machine. The rotational drive is used to drive the workpiece disk to perform in-situ rotation with the center of the circle as the center of the circle. The irradiation light source is installed in the vacuum coating machine and is located below the workpiece disk. The light converging element is installed on the vacuum coating machine, and each grating monochromator is located outside the vacuum coating machine.

[0018] Preferably, a light-transmitting window is embedded in the vacuum coating machine; the light converging element is installed outside the vacuum coating machine, and the light converging element, the light-transmitting window and the irradiation light source are aligned.

[0019] The present invention has achieved the following technical effects compared with the prior art:

[0020] The optical thin film thickness monitoring device proposed by the present invention monitors the transmittance or reflectance of multiple wavelengths simultaneously according to the change in light intensity generated by the change in the thin film thickness during the coating process. Through the relationship between the phase thicknesses corresponding to multiple wavelengths and in combination with the dispersion of the material, the actual physical or optical thickness of the thin film can be accurately calculated by software, and the accuracy is higher than that of single-wavelength thin film thickness monitoring. At the same time, multiple grating monochromators are used to monitor one wavelength respectively, and each grating monochromator can freely select the wavelength, with a wide wavelength selection range; the problem of large deviation in positioning accuracy caused by changing the monitoring wavelength of the same grating monochromator is avoided. The above-mentioned optical thin film thickness monitoring device can improve the measurement accuracy of the optical thin film thickness during the online monitoring of the coating process in the vacuum coating field, realize the real-time accurate control of the online thickness of complex film systems, and is beneficial to improving the coating success rate.

[0021] In some technical solutions disclosed by the present invention, by connecting the light converging element and each grating monochromator through a bifurcated optical fiber, real-time optical signals of multiple wavelengths at the same monitoring position can be obtained in the same time state, with strong synchronism, which is beneficial to improving the monitoring accuracy.

[0022] The optical thin film coating system proposed by the present invention includes the above-mentioned optical thin film thickness monitoring device. During the coating process, the optical thin film thickness monitoring device can monitor the optical signals of two or more specific wavelengths, so that the actual physical or optical thickness of the thin film can be accurately calculated, and the coating success rate of complex film systems can be improved. Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 It is a schematic diagram of the overall structure of the optical thin film thickness monitoring device disclosed in the embodiments of the present invention;

[0025] Figure 2 It is a top view of the workpiece disk disclosed in the embodiments of the present invention;

[0026] Figure 3 is Figure 1 an enlarged schematic view of part A in

[0027] Figure 4 is Figure 3 Schematic diagram of the cross-sectional shape at position B in

[0028] Figure 5 is Figure 3 Schematic diagram of the cross-sectional shape at position C in

[0029] In the figure, the reference numerals are: 100, optical thin film thickness monitoring device;

[0030] 1, workpiece disk;

[0031] 2, vacuum coating machine; 21, light-transmitting window;

[0032] 3, rotation drive;

[0033] 4, monitoring hole group; 41, through hole 1; 42, through hole 2; 43, spaced-apart shielding area; 44, coating monitoring film;

[0034] 5, irradiation light source; 51, light source support;

[0035] 6, light converging element;

[0036] 7, grating monochromator 1;

[0037] 8, grating monochromator 2;

[0038] 9, bifurcated optical fiber; 91, main optical fiber; 92, branch optical fiber; 93, optical fiber core bundle;

[0039] 10, control terminal;

[0040] 11, electron gun;

[0041] 12, photodetector;

[0042] 13, circumference. Specific embodiments

[0043] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0044] One of the objectives of the present invention is to provide a novel optical thin film thickness monitoring device to solve the problem that the monitoring accuracy of the existing single wavelength is insufficient, and when changing the monitoring wavelength, due to the repeated positioning accuracy deviation of the grating monochromator, the monitoring accuracy is still insufficient.

[0045] Another object of the present invention is to provide an optical thin film coating system including the above optical thin film thickness monitoring device.

[0046] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] Embodiment 1

[0048] This embodiment provides an optical thin film thickness monitoring device 100 for use by being installed on a vacuum coating machine 2; the vacuum coating machine 2 is a finished product with a mature coating function, and the specific structure and coating principle of the vacuum coating machine 2 will not be elaborated here. The optical thin film thickness monitoring device 100 can perform real-time thickness monitoring on the optical thin film on the upper surface of the workpiece tray 1 during the coating process of the coating machine. As Figure 1 shown, the optical thin film thickness monitoring device 100 includes a workpiece tray 1, an irradiation light source 5 and a receiving component. Among them, the workpiece tray 1 is used to be installed in the coating chamber of the vacuum coating machine 2 and is connected to the rotation drive 3 of the vacuum coating machine 2. The rotation drive 3 generally uses a drive motor, and the motor shaft penetrates through the coating chamber and extends into the coating chamber. The workpiece tray 1 is coaxially connected to the end of the motor shaft. The workpiece tray 1 is used to place the optical thin film, so that the workpiece tray 1 can be driven by the motor to rotate in place around the motor shaft, enabling the vapor ejected by the electron gun 11 in the coating chamber to be evenly coated on the surface of the thin film to achieve coating. The workpiece tray 1 is a common coating component in the field of optical coating, and can be in a flat shape or Figure 1 shown in the shape of an umbrella (also known as a "coating umbrella"); the difference is that this solution also opens a monitoring hole group 4 on the workpiece tray 1. As Figure 2 shown, the monitoring hole group 4 includes a through hole one 41, a through hole two 42 and an interval shielding area 43 located between the through hole one 41 and the through hole two 42. The interval shielding area 43 is essentially the unopened area of the workpiece tray 1, and the through hole one 41 and the through hole two 42 are spaced apart through this area. Considering that the workpiece tray 1 is in a continuous rotating state during the coating process, preferably, the through hole one 41 and the through hole two 42 are located on the same circumference 13, and the circumference 13 and the circular workpiece tray 1 are concentric structures. One of the through hole one 41 and the through hole two 42 is provided with a coating monitoring piece 44, and the other remains unobstructed; as a preferred solution, the coating monitoring piece 44 is inlaid in the through hole one 41. The coating monitoring piece 44 can be an optical lens with a certain refractive index, such as a transparent glass sheet, etc. Combining Figure 2It can be seen that the through hole one 41, the through hole two 42 and the spaced shielding area 43 in the same monitoring hole group 4 are arranged adjacent to each other. Multiple groups of monitoring hole groups 4 can be arranged at intervals on the circumference 13 as needed to improve the monitoring frequency. The irradiation light source 5 is used to be installed in the coating chamber of the vacuum coating machine 2 and is located below the workpiece disk 1. At the same time, the irradiation light source 5 is generally located above the coating thickness correction plate. After the irradiation light source 5 is installed, its position is fixed and is used to emit optical signals to the monitoring hole group 4. Each time the monitoring hole group 4 rotates to the light emission area of the irradiation light source 5, signals will pass through the monitoring hole group 4 for the receiving component to receive. The receiving component includes a light converging element 6 and at least two grating monochromators. The light converging element 6 is used to be installed on the vacuum coating machine 2. Each grating monochromator is connected to the output end of the light converging element 6 through an optical fiber. The light converging element 6 is used to receive the optical signals passing through the monitoring hole group 4 and simultaneously transport the received optical signals into each grating monochromator. The output end of any one grating monochromator is connected to a photodetector 12. The photodetector 12 can convert the quasi-monochromatic light λ selected by the corresponding grating monochromator into a corresponding electrical signal S and output it. As a preferred solution, the output end of each grating monochromator is respectively connected to a photodetector 12.

[0049] The above optical thin film thickness monitoring device 100 has a novel and reasonable structural design. By simultaneously setting at least two grating monochromators, it can monitor multiple wavelengths of the received optical signals at the same time. Each grating monochromator corresponds to monitoring one wavelength, which can meet the high-precision thickness monitoring requirements of special film systems such as dual-channel filters. For example, for a dual-channel filter, it has requirements for the transmittance in two regions and needs to monitor two wavelengths simultaneously to ensure the film thickness monitoring accuracy and the success rate of coating.

[0050] In some embodiments, the optical thin film thickness monitoring device 100 further includes a control terminal 10. The output end of any one photodetector 12 is communicatively connected to the control terminal 10. The control terminal 10 can preferably be a computer.

[0051] In some embodiments, the optical thin film thickness monitoring device 100 further includes an analog-to-digital converter (not shown in the figure). The output end of any one photodetector 12 is communicatively connected to the control terminal 10 through the analog-to-digital converter.

[0052] In some embodiments, the output end of the light converging element 6 is connected to at least two grating monochromators through a bifurcated optical fiber 9. Among them, the bifurcated optical fiber 9 includes a main optical fiber 91 and at least two branch optical fibers 92. One end of the main optical fiber 91 is connected to the output end of the light converging element 6, and all the branch optical fibers 92 are connected to the other end of the main optical fiber 91; the branch optical fibers 92 are connected to the grating monochromators in a one-to-one correspondence, and at least two branch optical fibers 92 are simultaneously connected to the grating monochromators. That is to say, if there are more than three branch optical fibers 92 in the bifurcated optical fiber 9, when in use, it is not necessary for each branch optical fiber 92 to be connected to the grating monochromator, but at least two of them must be simultaneously connected to the grating monochromator.

[0053] In some embodiments, the bifurcated optical fiber 9 may specifically be a Y-shaped optical fiber including two branch optical fibers 92, such as Figure 2 and Figure 3 shown, which is a schematic diagram of the Y-shaped optical fiber.

[0054] In some embodiments, such as Figure 3 and Figure 4 shown, the cross-section of the optical fiber core bundle 93 in the main optical fiber 91 is preferably circular. The circular structure has a larger light receiving area, which is beneficial to improving the light receiving efficiency. At the same time, preferably, the cross-section of the optical fiber core bundle 93 in any one of the branch optical fibers 92 is Figure 5 shown as a long strip shape, so as to better fit and plug into the entrance slit interface of the grating monochromator.

[0055] In some embodiments, in order to further improve the monitoring accuracy, it is preferred that the arc lengths occupied by the through hole one 41, the through hole two 42 and the spaced-apart shielding area 43 of each group of monitoring hole groups 4 on the circumference 13 are the same. The through hole one 41 and the through hole two 42 can both be circular holes or both be rectangular holes, and can also be both set as fan-shaped holes. The specific hole shape can be flexibly adjusted according to needs. In each group of monitoring hole groups 4, the through hole one 41, the through hole two 42 and the spaced-apart shielding area 43 are arranged adjacent to each other seamlessly. The central angle occupied by each group of monitoring hole groups 4 on the workpiece disk 1 is preferably 5° to 80°. Generally, the larger the outer diameter of the coating umbrella, the relatively smaller the central angle corresponding to each group of monitoring hole groups 4.

[0056] In some embodiments, the irradiation light source 5 is preferably a white light source, such as a halogen lamp, which can be fixed on the inner wall of the coating chamber through a light source bracket 51. The light source bracket 51 can be a fixed bracket or an adjustable bracket capable of adjusting the position and angle of the irradiation light source 5.

[0057] In some embodiments, the light focusing element 6 is preferably a focusing lens, such as a common convex lens, an achromatic lens combination, etc. Taking the achromatic lens combination as an example, it can ensure that light of different wavelengths can be focused near the receiving end face of the main optical fiber 91, improve the light receiving efficiency, and further improve the monitoring accuracy. The achromatic lens combination is a mature optical device, and its specific structure and principle are common knowledge in the art, so they will not be elaborated here.

[0058] Next, taking the example that the receiving component of the optical thin film thickness monitoring device 100 is provided with two grating monochromators, its usage method and monitoring principle will be specifically described. Among them, the two grating monochromators are grating monochromator one 7 and grating monochromator two 8 respectively.

[0059] The workpiece disk 1 is used to place the optical thin film. The irradiation light source 5 can be installed in the side wall of the coating chamber of the vacuum coating machine 2 through the light source bracket 51 and is located below the workpiece disk 1; at the same time, the light focusing element 6 is installed on the vacuum coating machine 2, and the light focusing element 6 and the irradiation light source 5 are respectively located on the upper and lower sides of the workpiece disk 1. At this time, the positions of the light focusing element 6 and the irradiation light source 5 are fixed.

[0060] A set of monitoring hole groups 4 are formed on the workpiece disk 1. Each time the monitoring hole group 4 rotates between the light focusing element 6 and the irradiation light source 5, the irradiation light source 5 sequentially irradiates the through hole one 41, the interval shielding area 43, and the through hole two 42. The light focusing element 6 sequentially collects the optical signals passing through the through hole one 41, the interval shielding area 43, and the through hole two 42. The optical signals corresponding to the through hole one 41, the interval shielding area 43, and the through hole two 42 are the test signal M, the dark signal B, and the reference signal R respectively. The transmittance T of the thin film can be expressed as: T=(M - B) / (R - B). It should be noted that the optical signal emitted by the irradiation light source 5 should be perpendicular to the workpiece disk 1. For example, when the workpiece disk 1 adopts a coating umbrella, as Figure 1 shown, since the coating umbrella is a spherical structure, the through hole one 41, the interval shielding area 43, and the through hole two 42 all have a certain curvature. At this time, the irradiation light source 5 is arranged obliquely so that the optical signal emitted by the irradiation light source 5 is always located on the spherical radial direction of the through hole one 41, the interval shielding area 43, and the through hole two 42. However, considering the actual deviation, during actual installation, ensure that the filament of the irradiation light source 5 (such as a halogen lamp) is aligned with the center of the receiving end face of the main optical fiber 91, and the connection line between the filament of the irradiation light source 5 (such as a halogen lamp) and the center of the receiving end face of the main optical fiber 91 is perpendicular to the through hole one 41 (monitoring film), the interval shielding area 43, and the through hole two 42.

[0061] The light focusing element 6 receives one signal group each time (including the test signal M, the dark signal B, and the reference signal R). Each signal in this signal group will flow to the grating monochromator one 7 and the grating monochromator two 8 simultaneously through the corresponding branch optical fiber 92.

[0062] An optoelectronic detector 12 is installed at the exit slit of each of the grating monochromator 1 - 7 and the grating monochromator 2 - 8. The optoelectronic detector 12 can respectively convert the energies of the two quasi - monochromatic lights λ1 and λ2 selected by the two grating monochromators into electrical signals S1 and S2. λ1 and λ2 are different. The electrical signals S1 and S2 are current or voltage signals.

[0063] After the electrical signals S1 and S2 respectively pass through an analog - to - digital converter, they are converted from analog electrical signals into digital signals that can be recognized by a computer terminal.

[0064] For a thin film with the same physical thickness, the wavelengths λ1 and λ2 correspond to different optical thicknesses, resulting in different transmittance signals S1 and S2 of the lights emitted by the two grating monochromators. Each layer of the thin film has different transmittance T values corresponding to the two wavelengths. According to the thin - film theory, the phase thickness corresponding to each wavelength can be calculated through the transmittance T, and thus two physical thickness values can be calculated. Combining with the dispersion factor of the material, a more accurate thin - film physical thickness value can be obtained compared to single - wavelength monitoring.

[0065] After the electrical signals of the optoelectronic detector 12 pass through analog - to - digital conversion, the data is read into the computer. Since the change in the thin - film thickness will cause a change in the transmittance T, therefore, according to the change law of the optical signal and some software algorithms, the phase thicknesses of the thin film corresponding to the two wavelengths can be respectively obtained. By comparing the phase thicknesses of the thin film corresponding to the two wavelengths, the accuracy is higher than that of single - wavelength thin - film thickness monitoring.

[0066] The above is the dual - wavelength thickness monitoring process of the optical thin - film thickness monitoring device 100, which realizes the simultaneous monitoring of the thickness of the same layer of optical thin film with two wavelengths decomposed by two grating monochromators. In practical applications, by increasing the number of grating monochromators, a multi - wavelength thickness monitoring process can be realized to meet higher accuracy requirements and the thickness monitoring requirements of different film systems.

[0067] In summary, the optical thin - film thickness monitoring device 100 proposed in this solution simultaneously monitors the transmittance or reflectance of two wavelengths according to the change in light intensity caused by the change in thin - film thickness during the coating process. It can not only improve the monitoring accuracy of a specific film layer by changing the wavelength, but also calculate the phase thicknesses of the two wavelengths by the computer respectively. Through the relationship between the phase thicknesses corresponding to the two wavelengths and combining with the dispersion of the material, the actual physical or optical thickness of the thin film can be accurately calculated by software, and the accuracy is higher than that of single - wavelength thin - film thickness monitoring. At the same time, multiple grating monochromators are used to respectively monitor one wavelength, and each grating monochromator can freely select the wavelength, with a wide wavelength selection range; it avoids the problem of large deviation in positioning accuracy when changing the monitoring wavelength of the same grating monochromator. In addition, through the branched optical fiber, real - time optical signals of multiple wavelengths at the same monitoring position in the same time state can be obtained, with strong synchronism, which is beneficial to improving the monitoring accuracy.

[0068] The optical thin-film thickness monitoring device 100 of this solution can improve the measurement accuracy of the optical thin-film thickness during the online monitoring of the coating process in the vacuum coating field, realize the real-time precise control of the online thickness of complex film systems, and is conducive to improving the coating success rate.

[0069] Embodiment 2

[0070] This embodiment provides an optical thin-film coating system, including a vacuum coating machine 2 and the optical thin-film thickness monitoring device 100 disclosed in Embodiment 1. Based on this, the optical thin-film coating system simultaneously has the functions of coating and real-time accurate monitoring of the film thickness. The vacuum coating machine 2 is a finished product with a mature coating function. The specific structure and coating principle of the vacuum coating machine 2 will not be elaborated here. The optical thin-film thickness monitoring device 100 can perform real-time thickness monitoring on the optical thin film on the upper surface of the workpiece disk 1 during the coating process of the coating machine. Combining Figure 1 As can be seen, the workpiece disk 1 is installed in the coating chamber of the vacuum coating machine 2 and is connected to the rotation drive 3 of the vacuum coating machine 2. The rotation drive 3 generally uses a drive motor. The motor shaft penetrates through the coating chamber and extends into the coating chamber. The workpiece disk 1 is coaxially connected to the end of the motor shaft. The workpiece disk 1 is used to place the optical thin film, so that the workpiece disk 1 can be driven by the motor to rotate in situ with the motor shaft as the axis (that is, the workpiece disk 1 rotates in situ with the center of the circle 13 as the center of the circle), so that the vapor sprayed by the electron gun 11 in the coating chamber is evenly coated on the surface of the thin film to achieve coating. The workpiece disk 1 is a common coating component in the optical coating field and can be flat or Figure 1 umbrella-shaped (also known as "coating umbrella") as shown; the difference is that this solution also offers a monitoring hole group 4 on the workpiece disk 1; the irradiation light source 5 can be installed in the side wall of the coating chamber of the vacuum coating machine 2 through the light source bracket 51 and is located below the workpiece disk 1; at the same time, the light focusing element 6 is installed on the vacuum coating machine 2, and the light focusing element 6 and the irradiation light source 5 are respectively located on the upper and lower sides of the workpiece disk 1. During use, the positions of the light focusing element 6 and the irradiation light source 5 are fixed. While the workpiece disk 1 continuously rotates for coating, the monitoring hole group 4 reciprocally rotates between the light focusing element 6 and the irradiation light source 5 to achieve real-time film thickness monitoring. Each grating monochromator is located outside the vacuum coating machine 2. As Figure 1 shown, each grating monochromator is connected to the light focusing element 6 through an optical fiber.

[0071] In this embodiment, the light converging element 6 can be installed on the top of the inner wall of the coating chamber of the vacuum coating machine 2, or can be installed outside the coating chamber. When the light converging element 6 is installed inside the coating chamber, it is necessary to penetrate the optical fiber through the coating chamber, which may affect the vacuum degree and sealing performance of the coating chamber. In order to avoid the installation of the receiving component from affecting the vacuum degree and sealing performance of the coating chamber, it is preferred that the light converging element 6 be installed outside the coating chamber. Specifically, a through opening can be provided in the top wall of the coating chamber, and a light-transmitting glass plate or resin plate can be inlaid in the through opening for sealing, so as to form a light-transmitting window 21; the light converging element 6 can be installed and fixed on the outer wall of the coating chamber of the vacuum coating machine 2 through an installation structure such as a base, and the light converging element 6, the light-transmitting window 21 and the irradiation light source 5 are aligned, so that the light converging element 6 can receive the optical signal emitted by the irradiation light source 5. In practical applications, another way to install the light converging element 6 outside the coating chamber is that the incident end of the light converging element 6 is hermetically fitted with the top wall of the coating chamber, which not only ensures the sealing of the coating chamber, but also ensures that the optical signal passing through the monitoring hole group 4 directly enters the incident end of the light converging element 6, reducing light loss.

[0072] During the coating process of the above optical thin film coating system, the optical thin film thickness monitoring device 100 can monitor optical signals of two or more specific wavelengths, so that the actual physical or optical thickness of the thin film can be accurately calculated, and the coating success rate of complex film systems can be improved.

[0073] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those who are familiar with this technology to understand and read, and are not used to limit the limiting conditions under which the present invention can be implemented. Therefore, they do not have substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope under which the present invention can be implemented. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope under which the present invention can be implemented.

[0074] In the present invention, specific examples are used to elaborate the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. An optical thin film thickness monitoring device, characterized in that, Comprising: A workpiece disk, which is used to be installed in a vacuum coating machine and is rotationally drivenly connected to the vacuum coating machine. The workpiece disk is used to place an optical thin film. A monitoring hole group is formed on the workpiece disk. The monitoring hole group includes a through hole one, a through hole two, and an interval shielding area located between the through hole one and the through hole two. The through hole one and the through hole two are located on the same circumference, and a coating monitoring film is arranged in one of the through hole one and the through hole two. An irradiation light source, which is used to be installed in the vacuum coating machine and is located below the workpiece disk. The irradiation light source is used to emit an optical signal to the monitoring hole group. A receiving component, including a light converging element and at least two grating monochromators. The light converging element is used to be installed on the vacuum coating machine. Each grating monochromator is connected to the output end of the light converging element through an optical fiber. The light converging element is used to receive the optical signal passing through the monitoring hole group and simultaneously transmit the optical signal to each grating monochromator. The output end of any one of the grating monochromators is connected to a photodetector. The photodetector can convert the quasi-monochromatic light λ selected by the corresponding grating monochromator into a corresponding electrical signal S and output it.

2. The optical thin film thickness monitoring device according to claim 1, wherein It further includes a control terminal. The output end of any one of the photodetectors is communicatively connected to the control terminal.

3. The optical thin film thickness monitoring device according to claim 2, characterized in that, It further includes an analog-to-digital converter. The output end of any one of the photodetectors is communicatively connected to the control terminal through the analog-to-digital converter.

4. The optical thin film thickness monitoring device according to any one of claims 1 to 3, characterized in that, The output end of the light converging element is connected to at least two of the grating monochromators through a bifurcated optical fiber. Wherein, the bifurcated optical fiber includes a main optical fiber and at least two branch optical fibers. One end of the main optical fiber is connected to the output end of the light converging element, and all the branch optical fibers are connected to the other end of the main optical fiber. The branch optical fibers are connected to the grating monochromators in a one-to-one correspondence, and at least two of the branch optical fibers are simultaneously connected to the grating monochromators.

5. The optical thin film thickness monitoring device according to claim 4, characterized in that, The bifurcated optical fiber is a Y-shaped optical fiber including two branch optical fibers.

6. The optical thin film thickness monitoring device according to claim 4, wherein The cross-section of the optical fiber core bundle in the main optical fiber is circular; the cross-section of the optical fiber core bundle in any one of the branch optical fibers is strip-shaped.

7. The optical thin film thickness monitoring device according to any one of claims 1 to 3, characterized in that, The through hole one, the through hole two, and the interval shielding area have the same arc length on the circumference.

8. The optical thin film thickness monitoring device according to any one of claims 1 to 3, characterized in that The irradiation light source is a white light source, and the light converging element is a converging lens.

9. An optical thin film coating system, comprising a vacuum coating machine and the optical thin film thickness monitoring device according to any one of claims 1 to 8, characterized in that, The workpiece disk is installed in the vacuum coating machine and is rotationally drivenly connected to the vacuum coating machine. The rotational drive is used to drive the workpiece disk to perform in-situ rotation with the center of the circle as the center of the circle. The irradiation light source is installed in the vacuum coating machine and is located below the workpiece disk. The light converging element is installed on the vacuum coating machine, and each grating monochromator is located outside the vacuum coating machine.

10. The optical thin film coating system according to claim 9, characterized in that, A light-transmitting window is embedded on the vacuum coating machine. The light converging element is installed outside the vacuum coating machine, and the light converging element, the light-transmitting window, and the irradiation light source are aligned.

Images