Film thickness detection device

Abstract

The present application provides a film thickness detection device, which includes: a common electrode unit, including a common electrode; a detection electrode unit, which is opposite to the common electrode unit in a first direction and is arranged at a distance, the detection electrode unit includes a detection electrode, a detection electrode cover plate, a second frame, an intermediate layer and a conductive layer, the intermediate layer is located on the surface of the detection electrode cover plate, the conductive layer is located on the surface of the intermediate layer away from the detection electrode cover plate, the surface roughness of the intermediate layer is less than the surface roughness of the detection electrode cover plate, the second frame has a second opening, the detection electrode cover plate is covered on the second opening of the second frame, the second frame and the detection electrode cover plate form a second accommodating space, the detection electrode is located in the second accommodating space, the dielectric constant of the detection electrode cover plate is greater than 3.9, the first direction is parallel to the thickness direction of the detection electrode cover plate, and a detection channel is formed between the common electrode unit and the detection electrode unit. This scheme improves the sensitivity of the film thickness detection device.

Description

Technical Field

[0001] The present application relates to the field of film thickness detection, and in particular, to a film thickness detection device. Background Art

[0002] The existing film thickness detection device uses the principle of electrostatic charge induction to detect the film thickness. When the existing film thickness detection device is working, a pulse signal is applied to the common electrode, and a voltage signal will be induced on the electrostatic charge sensing chip. When the film to be detected passes over the electrostatic charge sensing chip, the voltage on the electrostatic charge sensing chip will change. The magnitude of the voltage change is related to the nature and thickness of the film passing through. Since the detection circuit is electrically connected to the detection electrode, and the circuit structure of the detection circuit can convert the obtained voltage change value into the thickness of the film to be detected, the detection device can detect the thickness of the film to be detected, and then determine whether the thickness of the film is abnormal, and whether there are foreign objects, defects or folds on its surface. The ITO layer can effectively shield the electrostatic charge generated by the friction between the common electrode cover plate and the detection electrode cover plate when the film to be detected passes through the film thickness detection device, and can also shield the electrostatic charge carried by the film to be detected itself, thereby eliminating the interference caused by these electrostatic charges on the voltage change of the detection electrode, and improving the accuracy of the detection signal.

[0003] The above-mentioned film thickness detection device that has been disclosed so far uses a cover plate made mainly of glass for the common electrode unit and the detection electrode unit. The above-mentioned film thickness detection device has the following disadvantages: 1. The dielectric constant is small, and the detection accuracy of the film thickness is low; 2. The sensitivity is low, and the detection accuracy of the film thickness is low; 3. The cover plate made of glass has low hardness, is fragile and easy to wear, resulting in poor structural strength and stability of the film thickness detection device. The product is easy to deform under ambient temperature changes and external forces, and has a short service life; 3. Some have rough and uneven surfaces, and the surface is easy to adhere to dirt and is difficult to clean, which makes it difficult for the ITO layer to adhere to the cover plate, and causes different adhesion of the ITO layer at different positions on its surface, resulting in uneven thickness and resistance of the produced ITO layer, which makes the sensitivity of the film thickness detection device at different positions vary greatly, and the accuracy of film thickness detection is low;

[0004] The above information disclosed in the background technology section is only used to enhance the understanding of the background technology of the technology described in this article. Therefore, the background technology may contain certain information that does not form the prior art known in this country for those skilled in the art. Summary of the invention

[0005] The main purpose of the present application is to provide a film thickness detection device to solve the problem of low thickness detection accuracy of the film thickness detection device in the prior art.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a film thickness detection device is provided, which includes: a common electrode unit, including a common electrode; a detection electrode unit, which is opposite to the common electrode unit in a first direction and is arranged at a distance, the detection electrode unit includes a detection electrode, a detection electrode cover plate, a second frame, an intermediate layer and a conductive layer, the intermediate layer is located on the surface of the detection electrode cover plate, the conductive layer is located on the surface of the intermediate layer away from the detection electrode cover plate, the surface roughness of the intermediate layer is less than the surface roughness of the detection electrode cover plate, the second frame has a second opening, the detection electrode cover plate is covered on the second opening of the second frame, the second frame and the detection electrode cover plate form a second accommodating space, the detection electrode is located in the second accommodating space, the dielectric constant of the detection electrode cover plate is greater than 3.9, the first direction is parallel to the thickness direction of the detection electrode cover plate, and a detection channel is formed between the common electrode unit and the detection electrode unit.

[0007] Furthermore, the intermediate layer is located on a first surface and / or a second surface, the first surface is a surface of the detection electrode cover plate close to the detection electrode, and the second surface is a surface of the detection electrode cover plate away from the detection electrode.

[0008] Furthermore, the detection electrode unit further includes a second circuit board, the second circuit board is located in the second accommodating space, and the detection electrode is arranged on a surface of the second circuit board close to the detection electrode cover plate.

[0009] Furthermore, the detection device also includes an electrostatic charge sensing chip, and the electrostatic charge sensing chip includes a plurality of the detection electrodes.

[0010] Furthermore, the detection device also includes a protective film, and the protective film is located on the exposed surface of the conductive layer.

[0011] Furthermore, the common electrode unit also includes a first frame, a common electrode cover and a first circuit board, the first frame has a first opening, the common electrode cover is covered on the first opening of the first frame, the first frame and the common electrode cover form a first accommodating space, the common electrode is located in the first accommodating space, the first circuit board is located in the first accommodating space, and the common electrode is located on the surface of the first circuit board close to the common electrode cover.

[0012] Furthermore, the detection electrode cover plate is at least one of the following: a ceramic cover plate, a quartz cover plate, and a mica cover plate.

[0013] Furthermore, the ceramic cover plate is at least one of the following: an oxide ceramic cover plate, a nitride ceramic cover plate, a carbide ceramic cover plate, and a metal ceramic cover plate.

[0014] Furthermore, the material of the intermediate layer includes at least one of aluminum oxide, silicon oxide and silicon nitride.

[0015] Furthermore, the conductive layer is at least one of the following: a conductive tape, a conductive ink layer, and an ITO layer.

[0016] Furthermore, the thickness of the ITO layer is greater than 5 nm, and the thickness of the intermediate layer is 90 micrometers to 200 micrometers.

[0017] By applying the technical solution of the present application, by setting the material of the detection electrode cover plate to a material with a high dielectric constant, the detection sensitivity is higher than that of the traditional thin film thickness detection device using a glass cover plate. The intermediate layer is used to improve the surface roughness of the detection electrode cover plate, which is beneficial to the adhesion of the conductive layer to the above-mentioned intermediate layer, thereby improving the conductivity of the detection electrode cover plate, and further improving the sensitivity and accuracy of the film thickness detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0019] Figure 1 A cross-sectional view of a film thickness detection device according to an embodiment of the present application is shown;

[0020] Figure 2 The embodiment according to the present application is shown Figure 1 A partial structural schematic diagram of a detection device;

[0021] Figure 3 A cross-sectional view of another film thickness detection device according to an embodiment of the present application is shown;

[0022] Figure 4 The embodiment according to the present application is shown Figure 3 A partial structural schematic diagram of a detection device; and

[0023] Figure 5 A cross-sectional view of another film thickness detection device according to an embodiment of the present application is shown.

[0024] The above drawings include the following reference numerals:

[0025] 10. Common electrode unit; 11. First frame; 12. First circuit board; 13. Common electrode; 14. Common electrode cover; 20. Detection electrode unit; 21. Second frame; 22. Second circuit board; 23. Detection electrode; 24. Detection electrode cover; 25. Conductive layer; 26. Intermediate layer; 27. Protective film; 30. Detection circuit; 40. Rod-shaped metal part. DETAILED DESCRIPTION

[0026] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0027] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0028] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be intermediate elements. Moreover, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element through a third element.

[0029] As introduced in the background technology, the film thickness detection device in the prior art has low thickness detection accuracy. In order to solve the problem of low thickness detection accuracy of the film thickness detection device as above, an embodiment of the present application provides a film thickness detection device.

[0030] Figure 1 is a schematic diagram of a film thickness detection device according to an embodiment of the present application, such as Figure 1 As shown, the detection device comprises:

[0031] The common electrode unit 10 includes a common electrode 13;

[0032] The detection electrode unit 20 is arranged opposite to the common electrode unit 10 in a first direction and spaced apart. The detection electrode unit 20 includes a detection electrode 23, a detection electrode cover plate 24, a second frame 21, an intermediate layer 26 and a conductive layer 25. The intermediate layer 26 is located on the surface of the detection electrode cover plate 24, and the intermediate layer 26 partially or completely covers the surface of the detection electrode cover plate 24. The conductive layer 25 is located on the surface of the intermediate layer 26 away from the detection electrode cover plate 24, and the conductive layer 25 partially or completely covers the surface of the intermediate layer 26. The surface roughness of the layer 26 is smaller than the surface roughness of the detection electrode cover plate 24. The second frame 21 has a second opening. The detection electrode cover plate 24 is covered on the second opening of the second frame 21. The second frame 21 and the detection electrode cover plate 24 form a second accommodating space. The detection electrode 23 is located in the second accommodating space. The dielectric constant of the detection electrode cover plate 24 is greater than 3.9. The first direction is parallel to the thickness direction of the detection electrode cover plate 24. A detection channel is formed between the common electrode unit 10 and the detection electrode unit 20.

[0033] In the above scheme, by setting the material of the detection electrode cover plate to a material with a high dielectric constant, the detection sensitivity is higher than that of the traditional thin film thickness detection device using a glass cover plate. The intermediate layer is used to improve the surface roughness of the detection electrode cover plate, which is beneficial to the adhesion of the conductive layer to the above intermediate layer, thereby improving the conductivity of the detection electrode cover plate, and further improving the sensitivity and accuracy of the film thickness detection device.

[0034] It should be noted that the dielectric constants of the intermediate layer and the conductive layer are both relatively large.

[0035] It should be noted that the above-mentioned detection electrode cover plate includes but is not limited to a ceramic cover plate, a quartz cover plate, and a mica cover plate.

[0036] Another embodiment of the present application is as follows: Figures 1 to 5 As shown, the intermediate layer 26 is located on the first surface and / or the second surface. The first surface is the surface of the detection electrode cover plate 24 close to the detection electrode 23, and the second surface is the surface of the detection electrode cover plate 24 away from the detection electrode 23. The above includes three situations: Figure 1 , Figure 3 and Figure 5As shown, the intermediate layer 26 is only located on the first surface, and the intermediate layer 26 partially or completely covers the first surface; the intermediate layer 26 is only located on the second surface, and the intermediate layer 26 partially or completely covers the second surface; the intermediate layer 26 is located on both the first surface and the second surface, and the intermediate layer 26 partially or completely covers the first surface, and the intermediate layer 26 partially or completely covers the second surface, that is, those skilled in the art can select the position and coverage area of ​​the intermediate layer 26 according to actual conditions and reasonably design the position of the conductive layer 25 according to the position of the intermediate layer 26, so as to improve the sensitivity and accuracy of the film thickness detection device.

[0037] Another embodiment of the present application, as Figure 1 , Figure 3 and Figure 5 As shown, the detection electrode unit 20 further includes a second circuit board 22 , the second circuit board 22 is located in the second accommodation space, and the detection electrode 23 is arranged on the surface of the second circuit board 22 close to the detection electrode cover plate 24 .

[0038] In another embodiment of the present application, the detection device further comprises an electrostatic charge sensing chip, the electrostatic charge sensing chip comprises a plurality of the detection electrodes, the plurality of detection electrodes are arranged along a second direction, and the second direction is perpendicular to the first direction.

[0039] An embodiment of the present application, such as Figure 1 , Figure 3 and Figure 5 As shown, the detection device further includes a detection circuit 30, which is located on the surface of the second circuit board 22 away from the detection electrode 23. When the film to be detected passes over the electrostatic charge sensing chip, the voltage on the electrostatic charge sensing chip will change. The magnitude of the voltage change is related to the properties and thickness of the film passing through. Since the detection circuit 30 is electrically connected to the detection electrode 23, and the circuit structure of the detection circuit 30 can convert the obtained voltage change value into the thickness of the film to be detected, the detection device can detect the thickness of the film to be detected, and then determine whether the thickness of the film is abnormal and whether there are foreign objects, defects or folds on its surface.

[0040] An embodiment of the present application, such as Figure 3 and 4 As shown, the detection device further includes a protective film 27, which is located on the exposed surface of the conductive layer 25. The protective film 27 is at least one of the following: a ceramic film, a glass slurry film, a mixture of silicon nitride and silicon dioxide, or a mixture of aluminum oxide and silicon oxide.

[0041] Another embodiment of the present application, as Figure 1 and Figure 3 As shown, the common electrode unit 10 further includes a first frame 11, a common electrode cover 14 and a first circuit board 12, the first frame 11 having a first opening, the common electrode cover 14 covering the first opening of the first frame 11, the first frame 11 and the common electrode cover 14 forming a first accommodating space, the common electrode 13 being located in the first accommodating space, the first circuit board 12 being located in the first accommodating space, and the common electrode 13 being located on the surface of the first circuit board 12 close to the common electrode cover 14, it should be noted that the common electrode cover is made of a glass cover or a non-glass cover.

[0042] Another embodiment of the present application, as Figures 1 to 5 As shown, the detection electrode cover plate 24 is at least one of the following: a ceramic cover plate, a quartz cover plate, and a mica cover plate. By setting the material of the detection electrode cover plate 24 to a material with a high dielectric constant, compared with a traditional film thickness detection device using a glass cover plate, the detection sensitivity is higher, and therefore the detection accuracy of the film thickness is higher.

[0043] In one embodiment of the present application, the above-mentioned ceramic cover plate is at least one of the following: an oxide ceramic cover plate, a nitride ceramic cover plate, a carbide ceramic cover plate, and a metal ceramic cover plate. By setting the material of the detection electrode cover plate to a material with a high dielectric constant, compared with a traditional thin film thickness detection device using a glass cover plate, the detection sensitivity is higher, and therefore the detection accuracy of the thin film thickness is higher. The ceramic substrate cover plate has high hardness, wear resistance, corrosion resistance, high temperature resistance, and is not easy to deform, thereby improving the structural strength and stability of the thin film detection device and increasing the service life of the thin film thickness detection device.

[0044] Another embodiment of the present application, as Figure 1 , Figure 3 and Figure 5 As shown, the material of the intermediate layer 26 includes at least one of aluminum oxide, silicon oxide and silicon nitride, specifically including the intermediate layer 26 made of a mixture of aluminum oxide and silicon oxide, the intermediate layer 26 made of a mixture of Si3N4 and SiO2, the intermediate layer 26 is a glass slurry layer, and when the intermediate layer 26 is made of a mixture of aluminum oxide and silicon oxide, the thickness of the intermediate layer 26 is greater than or equal to 90μm, which further improves the sensitivity and accuracy of the film thickness detection device.

[0045] An embodiment of the present application, such as Figures 1 to 5As shown, the conductive layer 25 is at least one of the following: conductive tape, conductive ink layer, ITO layer. Some common non-glass cover plates are not resistant to high temperatures, have low hardness and are easy to deform, making it difficult to make an ITO layer on their surface. Some have rough and uneven surfaces, are easy to adhere to dirt and are difficult to clean, resulting in different adhesion of the ITO layer at different positions on its surface, so that the thickness and resistance of the produced ITO layer are uneven, resulting in large differences in sensitivity at different positions of the film thickness detection device, and low accuracy in film thickness detection. In this solution, the surface roughness of the detection electrode cover plate 24 is improved by the intermediate layer 26, which is conducive to the adhesion of the conductive layer 25 to the intermediate layer 26, and the dielectric constants of the intermediate layer 26 and the conductive layer 25 are both large, thereby improving the conductivity of the detection electrode cover plate 24, and further improving the sensitivity and accuracy of the film thickness detection device.

[0046] In another embodiment of the present application, the thickness of the ITO layer is greater than 5 nm, and the thickness of the intermediate layer is 90 micrometers to 200 micrometers, which further improves the sensitivity and accuracy of the film thickness detection device.

[0047] An embodiment of the present application, such as Figure 5 As shown, the common electrode unit 10 is a rod-shaped metal member 40 , and the rod-shaped metal member 40 is at least one of the following: a cylinder, a cone, an arc-shaped body, a pivotally arranged roller, and a roller around which the film to be detected is wound.

[0048] Example 1

[0049] This embodiment provides a thin film thickness detection device, such as Figure 1 and Figure 2 As shown, the film thickness detection device includes a common electrode unit 10 and a detection electrode unit 20, wherein the common electrode unit 10 includes a common electrode 13 and a common electrode cover 14 arranged on a side close to the common electrode 13; the detection electrode unit 20 and the common electrode unit 10 are opposite to each other in a first direction and are arranged at intervals, and the detection electrode unit 20 includes a detection electrode 23, a detection electrode cover 24, a conductive layer 25 and an intermediate layer 26, the intermediate layer 26 is a glaze layer, the conductive layer 25 is an ITO layer, the detection electrode cover 24 is a ceramic substrate cover, the detection electrode cover 24 is arranged on a side of the detection electrode unit 20 close to the common electrode unit 10, the intermediate layer 26 is arranged on the surface of the detection electrode cover 24, and the conductive layer 25 is arranged on the exposed surface of the intermediate layer 26 away from the detection electrode cover 24. The above-mentioned “intermediate layer 26 is arranged on the surface of the detection electrode cover plate 24” includes various situations. Specifically, the glaze layer can be arranged only on the surface of the ceramic substrate cover plate close to the detection electrode (such as Figure 1As shown), it may also be arranged only on the surface of the ceramic substrate cover away from the detection electrode, or it may be arranged simultaneously on the surface of the ceramic substrate cover close to the detection electrode and on the surface away from the detection electrode. In addition, the glaze layer may be arranged on the ceramic substrate cover in the form of completely covering one side or both sides of the surface, or it may only cover a part of one side or both sides of the surface, and the ITO layer may be arranged on the exposed surface of the glaze layer away from the ceramic substrate cover in the form of completely covering the glaze layer, or it may only cover a part of the exposed surface of the glaze layer away from the ceramic substrate cover. Those skilled in the art may arrange the glaze layer at a suitable position on a suitable surface of the ceramic substrate cover, and arrange the ITO layer at a suitable position on the exposed surface of the glaze layer according to actual conditions, and the interval between the common electrode cover 14 and the detection electrode cover 24 in the first direction forms a detection channel for the object to be detected, or the interval between the common electrode cover 14 and the conductive layer 25 in the first direction forms the detection channel, and the first direction is parallel to the thickness direction of the common electrode cover 14 and the detection electrode cover 24. In this embodiment, the intermediate layer 26 is arranged on the surface of the detection electrode cover plate 24 close to the detection electrode 23, and the conductive layer 25 is arranged on the exposed surface of the intermediate layer 26 close to the detection electrode 23. Therefore, in this embodiment, the interval between the common electrode cover plate 14 and the detection electrode cover plate 24 in the first direction forms a detection channel for the object to be detected, which can prevent the ITO layer from being worn when the film to be detected passes through the film thickness detection device.

[0050] The above-mentioned ceramic substrate in the present application can be a common material ceramic substrate, which is sintered from natural materials such as feldspar, clay and quartz, and its main components are silicon, aluminum, oxygen, etc. Common ceramics are abundant in source, low in cost and mature in technology; it can also be a special material ceramic substrate, which is made of high-purity artificially synthesized raw materials and formed and sintered using precision controlled processes, such as oxide ceramics (aluminum oxide, zirconium oxide), nitride ceramics (aluminum nitride), carbide ceramics, metal ceramics, etc. The dielectric constant can be changed by changing the element ratio in the ceramic substrate to achieve control of the sensitivity of the film thickness detection device.

[0051] The ceramic substrate cover plate of the film thickness detection device of the embodiment of the present invention is provided with a glaze layer, so that the originally rough and uneven ceramic substrate surface becomes smooth and flat, the ITO layer is easy to adhere to the glaze layer surface, not easy to fall off, the resistance value is stable and does not change, the ITO layer is easy to control during the production process, the thickness and resistance value of the ITO layer are uniform, the sensitivity consistency of the film thickness detection device at different positions is ensured, and the accuracy of film thickness detection is improved. The glaze layer in the embodiment of the present invention is commonly a mixture of aluminum oxide and silicon oxide, etc., which is made on the surface of the ceramic substrate by screen printing and high-temperature sintering; it can also be made by vacuum sputtering using a target material with a special glaze composition. The thickness of the glaze layer can be controlled, and the setting of the thickness of the glaze layer is related to the roughness of the surface of the ceramic substrate. The glaze layer needs to reach a certain thickness to achieve the correction of the roughness and flatness of the surface of the ceramic substrate; at the same time, the thickness of the glaze layer is also related to the sensitivity of the film thickness detection device. For a ceramic substrate of a certain thickness, the greater the thickness of the glaze layer, the greater the sensitivity of the film thickness detection device. At present, the thickness of the glaze layer used in the film thickness detection device is preferably 90um or above. The glaze layer of the embodiment of the present invention can be replaced by a medium in the prior art that can correct the surface roughness of the ceramic substrate and whose surface can be used to make an ITO layer, such as a SIALON film, a SION film, etc., whose specific composition is a mixture of Si3N4 and SiO2, which is made on the surface of the ceramic substrate by vacuum sputtering; it can also be a glass slurry layer, which is made on the surface of the ceramic substrate by printing and high-temperature sintering.

[0052] The ITO layer of the present application can effectively shield the static charge generated by friction with the common electrode cover plate and the ceramic substrate cover plate when the film to be detected passes through the thickness detection device, and can also shield the static charge carried by the film itself, thereby avoiding the interference caused by these static charges on the voltage change of the detection electrode, improving the accuracy of the detection signal, and enabling the film thickness detection device to effectively and accurately detect the thickness information of the film. The ITO layer of the present application can be replaced by any conductive material in the prior art, such as a conductive tape and / or a conductive ink layer. Those skilled in the art can select a suitable conductive material according to actual conditions, preferably an ITO layer, which has simple production, and the resistance value, uniformity and thickness can be accurately controlled, and the ITO layer is stable and not easy to fall off, and its resistance value is stable, and does not change with the temperature and humidity of the environment. The ITO layer can be made on the surface of the glaze layer by vacuum sputtering or screen printing high temperature sintering. When a conductive ink layer is selected, it can be made on the surface of the glaze layer by screen printing or spraying. Those skilled in the art can choose to set the ITO layer to a suitable thickness according to actual conditions, and the thickness of the ITO layer is usually greater than 5nm. When different films or the same type of films pass through the film thickness detection device of the present invention at different speeds, the static charge generated by friction will be different, which requires the conductive material to have different conductivity to correspond to it, so as to effectively shield the interference of static charge on the film thickness information detection signal. The difference in the conductivity of the ITO layer is achieved by changing the percentage of the conductive material in the ITO layer and the thickness of the ITO layer. This method is simple to implement and can achieve fine adjustment of the conductivity change of the ITO layer, which is very helpful for shielding the interference of external static charge and improving the quality of the film thickness information detection signal. When a conductive ink layer is selected, the conductivity change of the conductive ink layer can be finely adjusted by changing the proportion of the conductive material in the conductive ink, such as the carbon element.

[0053] The common electrode cover of the present application can be made of a material that has no attenuation effect on the detection signal in the prior art, and can be made of glass; it can also be made of non-glass materials, such as ceramic materials, resin materials, plastic materials, etc., preferably a high dielectric cover made of ceramic materials.

[0054] The film thickness detection device of the embodiment of the present invention adopts a ceramic substrate cover plate, and a glaze layer is provided on the surface of the ceramic substrate cover plate. The ceramic substrate and the glaze layer are high dielectric materials. Therefore, compared with the traditional film thickness detection device using a glass cover plate, the detection sensitivity is higher, and the detection accuracy of the film thickness is higher. The ceramic substrate cover plate has high hardness, wear resistance, corrosion resistance, high temperature resistance and is not easy to deform, which improves the structural strength and stability of the film detection device and increases the service life of the film thickness detection device. In addition, the ceramic substrate cover plate of the embodiment of the present invention can be a quartz cover plate, a mica cover plate, and other high dielectric material cover plates that can be applied to the film thickness detection device.

[0055] The above-mentioned film thickness detection device of the present application includes an electrostatic induction chip, and the electrostatic induction chip includes a plurality of detection electrodes 23 to provide a plurality of detection electrodes. In order to improve the service life and firmness of the film thickness detection device, in the embodiment of the present application, Figure 1As shown, the common electrode unit 10 further includes a first frame 11, the first frame 11 and the common electrode cover 14 form a first accommodation space, and the common electrode 13 is arranged in the first accommodation space. The common electrode unit 10 further includes a first circuit board 12, the first circuit board 12 is arranged in the first accommodation space, and the common electrode 13 is arranged on the surface of the first circuit board 12 close to the common electrode cover 14. The detection electrode unit 20 further includes a second frame 21, the second frame 21 and the detection electrode cover 24 form a second accommodation space, and the detection electrode 23 is arranged in the second accommodation space. The second accommodation space formed by the second frame 21 and the detection electrode cover 24 can well protect the detection electrode 23 and prevent it from being worn, etc., and this structure is firm and has high reliability. The detection electrode unit 20 further includes a second circuit board 22 and a detection circuit 30. The second circuit board 22 is arranged in the second accommodation space, and the detection electrode 23 is arranged on the surface of the second circuit board 22 close to the detection electrode cover plate 24; the detection circuit 30 is arranged on the surface of the second circuit board 22 away from the detection electrode 23, and the detection circuit 30 includes a detection circuit electrically connected to the detection electrode 23. When the thickness detection device is used to detect the thickness of a film, a certain pulse signal is applied to the common electrode 13, and a certain voltage signal will be induced on the opposite detection electrode 23. When the film to be tested passes through the detection channel, the voltage signal on the detection electrode 23 will change, and the magnitude of the voltage change is related to the nature and thickness of the film passing through. Since the detection circuit is electrically connected to the detection electrode 23, and the circuit structure of the detection circuit can convert the obtained voltage change value into the thickness of the film to be tested, the detection circuit 30 can detect the thickness of the film, and then determine whether the thickness of the film is abnormal, and whether there are foreign matter, defects or folds on its surface. The film to be detected in the present application can be any thin sheet-like object in the prior art, such as banknotes, packaging films, etc. The conductive layer 25 can effectively shield the static charge generated by the friction between the film to be detected and the common electrode cover plate 14 and the detection electrode cover plate 24 when the film to be detected passes through the film thickness detection device, and can also shield the static charge carried by the film to be detected itself, thereby eliminating the interference caused by these static charges on the voltage change of the detection electrode 23, and improving the accuracy of the detection signal.

[0056] Example 1

[0057] like Figure 3 and Figure 4As shown, this embodiment provides a structural schematic diagram of another film thickness detection device, which is different from the first embodiment in that, in order to prevent the conductive layer 25 from being worn during the product assembly process, and when the common electrode cover plate 14 and the conductive layer 25 are spaced in the first direction to form a detection channel, in order to prevent the conductive layer 25 from being worn when the film to be detected passes through the detection channel, a protective film 27 is provided on the exposed surface of the conductive layer 25 away from the intermediate layer 26, and the protective film 27 completely covers the exposed surface of the conductive layer 25 away from the glaze layer. The protective film 27 can be made of an insulating material with good wear resistance and corrosion resistance, such as SIALON film, SION film, ceramic, glaze layer, glass slurry, a mixture of Si3N4 and SiO2, etc. These insulating materials are formed by vacuum sputtering, spraying, printing or high-temperature sintering; the protective film 27 can also be made of a conductive material with good conductivity, good wear resistance and corrosion resistance, and is formed by spraying, electroplating or printing. The thickness of the protective film 27 can be set according to the type of the film to be detected, the characteristics of the protective film itself and the actual use situation.

[0058] Example 3

[0059] like Figure 5As shown, this embodiment provides another film thickness detection device, which is different from the first and second embodiments in that the common electrode unit 10 is only composed of a rod-shaped metal member 40, and the rod-shaped metal member 40 includes a metal cylinder, a metal cylindrical shell, a metal cone, a pivotally arranged roller, a roller around which the object to be detected is wound, etc. The interval between the rod-shaped metal member 40 and the detection electrode cover plate 24 in the first direction forms a detection channel for the object to be detected, or the interval between the rod-shaped metal member 40 and the conductive layer 25 in the first direction forms the detection channel, or the interval between the rod-shaped metal member 40 and the protective film 27 in the first direction forms the detection channel, and the first direction is parallel to the thickness direction of the rod-shaped metal member 40 and the detection electrode cover plate 24. When the thickness detection device of this embodiment detects the thickness of the film, a certain pulse signal is applied to the rod-shaped metal piece 40, and a certain voltage signal will be induced on the detection electrode 23 opposite to it. When the film to be tested passes through the detection channel, the voltage signal on the detection electrode 23 will change. The magnitude of the voltage change is related to the nature and thickness of the object passing through. Since the detection circuit is electrically connected to the detection electrode 23, and the circuit structure of the detection circuit can convert the obtained voltage change value into the thickness of the film to be tested, the detection circuit 30 can detect the thickness of the film, and then determine whether the thickness of the film is abnormal, and whether there are foreign objects, defects or folds on its surface. The film thickness detection device of this embodiment uses a common electrode of a rod-shaped metal piece structure, so that the distance of the detection channel can be minimized to the maximum extent. At the same time, the common electrode of this structural form allows the electric field to be more concentrated on the detection electrode, thereby greatly improving the detection sensitivity of the film thickness detection device and improving the detection accuracy of the film thickness. The reduced spacing between the detection channels enables the film to be detected to stably pass through the film thickness detection device, reducing the shaking of the film, which is very useful for improving the detection accuracy of the film thickness, and at the same time suppresses the influence of the ambient temperature, humidity and the film's own characteristics such as humidity, cleanliness, newness, etc. on the film thickness detection accuracy. The structure and manufacturing process of the film thickness detection device of this embodiment are simpler and easier to operate, with lower production costs, suitable for mass production, and are very meaningful for miniaturization of the entire device and reduction of the price of the entire device.

[0060] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0061] The film thickness detection device of the present application has a higher detection sensitivity than the traditional thin film thickness detection device using a glass cover plate by setting the material of the detection electrode cover plate to a material with a high dielectric constant. The intermediate layer is used to improve the surface roughness of the detection electrode cover plate, which is beneficial to the adhesion of the conductive layer to the above-mentioned intermediate layer, thereby improving the conductivity of the detection electrode cover plate, and further improving the sensitivity and accuracy of the film thickness detection device.

[0062] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A film thickness detection device, characterized in that: include: A common electrode unit, comprising a common electrode; A detection electrode unit is arranged opposite to and spaced from the common electrode unit in a first direction, the detection electrode unit comprises a detection electrode, a detection electrode cover plate, a second frame, an intermediate layer and a conductive layer, the intermediate layer is located on the surface of the detection electrode cover plate, the conductive layer is located on the surface of the intermediate layer away from the detection electrode cover plate, the surface roughness of the intermediate layer is smaller than the surface roughness of the detection electrode cover plate, the second frame has a second opening, the detection electrode cover plate is covered on the second opening of the second frame, the second frame and the detection electrode cover plate form a second accommodating space, the detection electrode is located in the second accommodating space, the dielectric constant of the detection electrode cover plate is greater than 3.9, the first direction is parallel to the thickness direction of the detection electrode cover plate, and a detection channel is formed between the common electrode unit and the detection electrode unit.

2. The detection device according to claim 1, characterized in that: The intermediate layer is located on a first surface and / or a second surface, the first surface is a surface of the detection electrode cover plate close to the detection electrode, and the second surface is a surface of the detection electrode cover plate away from the detection electrode.

3. The detection device according to claim 1, characterized in that: The detection electrode unit further includes a second circuit board, the second circuit board is located in the second accommodation space, and the detection electrode is arranged on a surface of the second circuit board close to the detection electrode cover plate.

4. The detection device according to claim 1, characterized in that: The detection device further comprises an electrostatic charge sensing chip, and the electrostatic charge sensing chip comprises a plurality of the detection electrodes.

5. The detection device according to claim 1, characterized in that: The detection device further comprises a protective film, which is located on the exposed surface of the conductive layer.

6. The detection device according to claim 1, characterized in that: The common electrode unit also includes a first frame, a common electrode cover and a first circuit board, the first frame has a first opening, the common electrode cover is covered on the first opening of the first frame, the first frame and the common electrode cover form a first accommodating space, the common electrode is located in the first accommodating space, the first circuit board is located in the first accommodating space, and the common electrode is located on a surface of the first circuit board close to the common electrode cover.

7. The detection device according to any one of claims 1 to 6, characterized in that: The detection electrode cover plate is at least one of the following: Ceramic cover plate, quartz cover plate, mica cover plate.

8. The detection device according to claim 7, characterized in that: The ceramic cover plate is at least one of the following: Oxide ceramic cover plate, nitride ceramic cover plate, carbide ceramic cover plate, metal ceramic cover plate.

9. The detection device according to any one of claims 1 to 6, characterized in that: The material of the intermediate layer includes at least one of aluminum oxide, silicon oxide and silicon nitride.

10. The detection device according to any one of claims 1 to 6, characterized in that: The conductive layer is at least one of the following: Conductive tape, conductive ink layer, ITO layer.

11. The detection device according to claim 10, characterized in that: The thickness of the ITO layer is greater than 5 nm, and the thickness of the intermediate layer is 90 micrometers to 200 micrometers.

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