Photosensitive dry film and wet film thickness measuring device based on light interference technology

Abstract

The utility model discloses a photosensitive dry film and wet film thickness measuring device based on a light interference technology, the device comprises a base, a fixed seat, a support, a motion control assembly, a light interference assembly, a PLC and a human-computer interface, a thickness measuring method is adopted, the device adopts the light interference principle, the problem of film loss caused by contact measurement is solved, and the measuring accuracy is improved. Through clamping of the PLC and the human-computer interface, data processing and real-time display are achieved, efficiency is greatly improved, meanwhile, a dynamic compensation module is arranged, thickness measurement is not prone to external interference, and measurement precision is improved.

Description

Technical Field

[0001] This utility model relates to the field of thickness measurement technology, and in particular to a photosensitive dry film and wet film thickness measurement device based on optical interference technology. Background Technology

[0002] With the increasing refinement and modernization of industrial production, the requirements for film thickness measurement, accuracy, efficiency, and stability are becoming increasingly stringent. Photosensitive dry and wet films are key materials in printed circuit board (PCB) manufacturing, and the uniformity of their dry and wet film thickness directly affects the performance of the final product. The drawbacks of traditional dry and wet film thickness measurement methods (such as contact measurement) are becoming increasingly apparent, such as poor accuracy, easy damage to the film surface, and low measurement efficiency, making it difficult to meet the stringent requirements of current industrial production.

[0003] To address the aforementioned issues, researchers have improved the photosensitive dry film wet film thickness measurement device to achieve higher measurement efficiency and accuracy. Currently, commonly used methods for measuring film thickness mainly include contact measurement and non-contact measurement. Contact measurement primarily acquires relevant data when the film of the product under test is brought into contact with the substrate and the measuring unit using pressure, and then calculates the film thickness. Non-contact measurement methods mainly utilize the principle of optical interference; when light shines on the film, the two beams of light reflected from the upper and lower surfaces of the film interfere, and the film thickness is then calculated.

[0004] However, despite technological advancements, existing photosensitive dry and wet film thickness measurement devices still have shortcomings. First, measuring film thickness using contact methods such as pressure can easily damage the film surface. Second, when measuring film thickness using non-contact methods, manual calculations are required, and data cannot be displayed in real time, resulting in untimely information transmission. Furthermore, fluctuations in temperature and humidity during film thickness measurement can cause changes in the optical path difference, affecting the stability of interference fringes and thus reducing measurement accuracy.

[0005] Therefore, in the process of implementing the technical solution of the utility model in the embodiments of this application, the inventors of this application have discovered that the above-mentioned technology has the following technical problems:

[0006] 1. Contact measurement of the wet film thickness of photosensitive dry film can easily cause film damage;

[0007] 2. When measuring the thickness of photosensitive dry film and wet film, it is impossible to achieve multi-point measurement and real-time data display, resulting in untimely information transmission and low efficiency;

[0008] 3. During the measurement of film thickness, the measurement is easily affected by changes in temperature and humidity, resulting in low accuracy of the measurement values. Utility Model Content

[0009] This application provides a photosensitive dry film wet film thickness measurement device based on optical interferometry, which solves the technical problems of easy film damage, low efficiency and low measurement accuracy in the prior art when measuring the wet film thickness of photosensitive dry films.

[0010] This application provides a photosensitive dry film / wet film thickness measuring device based on optical interferometry, wherein the thickness measuring device includes:

[0011] A photosensitive dry film wet film thickness measurement device based on optical interferometry technology, comprising:

[0012] A fixed base, wherein the fixed base is connected to the base by a bracket.

[0013] Optical interference component, the optical interference component comprising:

[0014] The light source is fixed to the top of the bracket.

[0015] The beam splitter is located directly below the light source and is connected to the bracket by a fixed base. The light emitted by the light source is transmitted to the beam splitter through optical fiber. The beam splitter divides the light into a reference optical path and a measurement optical path. The measurement optical path is reflected back to the beam splitter after being reflected by a mirror.

[0016] A reflector, which is disposed on one side of the beam splitter and can be adjusted by a mechanism to fine-tune the angle and optimize the optical path;

[0017] A photodetector, fixed to a beam splitter, receives interference signals and transmits them to a PLC;

[0018] Motion control component, the motion control component comprising:

[0019] A linear guide rail, which is fixed to the middle of the top surface of the base and extends laterally;

[0020] A servo motor is fixed to one end of the base and driven by a linear guide rail, which drives the linear guide rail to achieve lateral movement for positioning measurement points.

[0021] The sensor is located between linear guide rails, and the servo motor drives the sensor to move laterally along the linear guide rails;

[0022] The encoder is coaxially mounted with the output shaft of the servo motor and rotates synchronously with it;

[0023] The PLC is fixed inside the base and connected to the encoder, photodetector, temperature sensor, humidity sensor and micro stepper motor respectively through signal lines;

[0024] A human-machine interface is embedded in the side of the base and connected to the PLC via a data cable.

[0025] Furthermore, the sensor is located between linear guide rails, and the motion control component drives the sensor to move laterally along the linear guide rails;

[0026] Furthermore, the optical interference component also includes a dynamic compensation module, which includes a temperature sensor, a humidity sensor, and an automatic calibration unit. The temperature sensor and humidity sensor are embedded inside the beam splitter mount and in close contact with it. The temperature sensor and humidity sensor monitor environmental parameters in real time and transmit the monitoring data to the PLC. The PLC generates compensation instructions to drive a micro stepper motor to adjust the position of the calibration plate to compensate for changes in optical path difference caused by temperature fluctuations.

[0027] Furthermore, the automatic calibration unit includes a calibration plate and a micro stepper motor. The calibration plate is located in the optical path between the beam splitter and the reflector and can move in the vertical direction. The micro stepper motor is fixed to the rear end of the beam splitter mounting base and connected to the calibration plate through a transmission rod.

[0028] Furthermore, the automatic calibration unit also includes a position feedback module, which includes a photoelectric encoder and a limit switch. The photoelectric encoder is fixed to the output shaft of the micro stepper motor and rotates synchronously with the transmission rod. The limit switch is fixed to the top of the beam splitter mounting base and corresponds to the end of the calibration piece's moving path. The position feedback module is connected to the PLC via a signal line to provide real-time position information of the calibration piece, ensuring accurate compensation.

[0029] This application also provides a method for measuring the wet film thickness of photosensitive dry film based on optical interferometry, including:

[0030] The S1 motion control component drives the sensor to move laterally along the linear guide rail, covering the entire photosensitive dry film and wet film measurement area.

[0031] The S2 optical interference component emits interference light, which is split into reference light and measurement light by a beam splitter. The measurement light illuminates the surface of the photosensitive dry film and wet film and is reflected, forming interference fringes with the reference light.

[0032] The S3 photodetector receives the interference fringe signal and transmits it to the PLC;

[0033] After receiving the signal, the S4 PLC performs filtering and data processing, calculates the thickness of the dry and wet films of the photosensitive film based on the changes in interference fringes, and issues motion control signal commands to adjust the position of the sensor.

[0034] After the S5 PLC processes the data, it transmits the relevant information to the human-machine interface. The human-machine interface receives the PLC signal and displays the relevant data in real time.

[0035] Furthermore, the relevant data displayed on the human interface includes measurement results (such as thickness value, uniformity analysis) and the horizontal coordinate position of the sensor on the film surface;

[0036] Furthermore, the motion control signal command includes information for dynamically adjusting the scanning speed of the servo motor based on real-time thickness data.

[0037] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0038] 1. This utility model uses optical interference technology to achieve non-contact measurement of the thickness of photosensitive dry and wet films, thus solving the problem of easy film damage.

[0039] 2. This utility model, through motion control components, PLC, and human interface design, realizes multi-point automated measurement and real-time data display, effectively solving the problems of untimely information transmission and low efficiency.

[0040] 3. This utility model achieves high precision in measurement results by designing an optical interference component, effectively solving the problem of being affected by changes in temperature and humidity. Attached Figure Description

[0041] Figure 1 This is a diagram illustrating the overall structure of this application;

[0042] Figure 2 These are partial cross-sectional views of embodiments of this application;

[0043] Figure 3 These are partial structural diagrams from embodiments of this application;

[0044] Figure 4 This is a schematic diagram of an embodiment of this application.

[0045] In the attached figures, the reference numerals represent: (1) base, (2) fixed base, (3) bracket, (4) sensor, (5) light source, (6) beam splitter, (7) reflector, (8) photodetector, (9) linear guide rail, (10) servo motor, (11) encoder, (12) PLC, (13) human-machine interface, (14) temperature sensor, (15) humidity sensor, (161) calibration plate, (162) micro stepper motor, (171) photoelectric encoder, (172) limit switch. Detailed Implementation

[0046] Existing photosensitive dry film and wet film measurement equipment suffers from shortcomings in terms of film non-destruction, low efficiency, and measurement accuracy. To overcome these problems, this application provides a photosensitive dry film and wet film thickness measurement device and its working method based on optical interferometry. By combining optical interferometry, PLC data processing, and human-machine interface display, it achieves high efficiency, accuracy, and film integrity in film thickness measurement.

[0047] The technical solution in this application embodiment is to solve the above-mentioned crosstalk problem, and the general idea is as follows:

[0048] The device consists of a base (1), a fixed base (2), a bracket (3), a motion control component, an optical interference component, a PLC (12), and a human-machine interface (13). The fixed base (2) is connected to the base (1) by the bracket (3).

[0049] A light source (5) is fixed on the top of the bracket (3). A beam splitter (6) is located directly below the light source (5). The beam splitter (6) and the light source (5) are connected by optical fiber. The beam splitter (6) and the bracket (3) are connected as one unit by a fixing seat (2). A reflector (7) is located on one side of the beam splitter (6), and a photodetector (8) is fixed on the other side. The reflector (7) can be finely adjusted in angle through an adjustment mechanism to optimize the optical path and facilitate the use of optical interference to measure thickness.

[0050] A linear guide rail (9) is fixed in the middle of the top surface of the base (1) and extends laterally. The sensor (4) is located between the linear guide rails (9). A servo motor (1) is fixed at one end of the base (1) and is driven by the linear guide rail (9). An encoder (11) is coaxially mounted on the output shaft of the servo motor (10) and rotates synchronously with it. The position feedback module includes a photoelectric encoder (171) and a limit switch (172). The photoelectric encoder (171) is fixed to the output shaft of the micro stepper motor (162) and rotates synchronously with the transmission rod. The limit switch... The switch (172) is fixed on the top of the beam splitter (6) mounting base and corresponds to the end of the moving path of the calibration plate (161). Inside the base (1), a PLC (12) is fixed. The PLC (12) is connected to the encoder (11), photodetector (8), temperature sensor (14), humidity sensor (15), micro stepper motor (162) and position feedback module through signal lines to obtain information. The human-machine interface (13) is embedded in the side of the base (1) and connected to the PLC (12) through a data line to display data in real time.

[0051] Temperature sensor (14) and humidity sensor (15) are embedded in the beam splitter (6) mounting base and in close contact with it, respectively, to monitor the temperature and humidity changes of the environment around the beam splitter (6) in real time and transmit the monitoring data to PLC (12). PLC (12) generates compensation instructions according to a preset algorithm and transmits them to micro stepper motor (162) through a signal line. Calibration plate (161) is located in the optical path between beam splitter (6) and reflector (7). Micro stepper motor (162) is fixed to the rear end of beam splitter (6) mounting base and connected to calibration plate (161) through a transmission rod. Micro stepper motor (162) drives calibration plate (161) to move in the vertical direction to adjust the optical path difference of the interference optical path, thereby offsetting the influence of temperature and humidity changes on the accuracy of optical interference measurement.

[0052] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0053] Example 1

[0054] The device in this embodiment consists of a base (1), a fixed base (2), a bracket (3), a sensor (4), a motion control component, an optical interference component, a PLC (12), and a human-machine interface (13). Meanwhile, a receiving groove is provided inside the fixed base of the beam splitter (6), and several heat-conducting sheets are provided on the inner wall of the receiving groove. One end of the heat-conducting sheet is in close contact with the temperature sensor (14) and the humidity sensor (15), and the other end extends to the outer wall of the fixed base of the beam splitter (6). Thermal grease is coated on the surface of the heat-conducting sheet.

[0055] The technical solutions described in the embodiments of this application have at least the following technical effects or advantages:

[0056] By using heat-conducting sheets and thermal grease, the heat dissipation efficiency of the equipment is improved, the normal operating temperature of the equipment is maintained, and its service life is extended.

[0057] Example 2

[0058] In this embodiment, the light source (5) is a narrow bandwidth laser and is equipped with a wavelength stabilization module. The wavelength stabilization module includes a temperature control circuit and a constant current source. Both are connected to the light source (5) through wires. However, the temperature control circuit is fixed at the bottom of the light source (5), and the constant current source is fixed at the side of the light source (5). The wavelength stabilization module is connected to the PLC (12) through a signal line. During the use of the device, the temperature changes, which will affect the wavelength of the light source (5) and is not conducive to thickness measurement. The wavelength stabilization module is set up to realize the real-time control of the wavelength of the light source (5).

[0059] The technical solutions described in the embodiments of this application have at least the following technical effects or advantages:

[0060] A wavelength stabilization module is used to achieve real-time control of the light source wavelength, thereby improving the accuracy of thickness measurement.

[0061] Example 3

[0062] In this embodiment, the calibration plate (161) is a rectangular thin sheet structure made of high refractive index material, and its surface is coated with an anti-reflection coating to reduce light energy loss. The calibration plate (161) is connected to the output shaft of the micro stepper motor (162) through a transmission rod, and an elastic buffer is provided between the transmission rod and the calibration plate (161). Because vibration is inevitable when the device is in operation, the elastic buffer can reduce the impact of vibration on the stability of the optical path.

[0063] The technical solutions described in the embodiments of this application have at least the following technical effects or advantages:

[0064] By using high refractive index materials and anti-reflective coatings, light energy loss is reduced, the impact of vibration on optical path stability is decreased, and the accuracy of thickness measurement is improved.

[0065] Example 4

[0066] Regarding the photosensitive dry film wet film thickness measuring device mentioned in the previous embodiment, this embodiment provides a measurement method applied to the equipment: the motion control component drives the sensor (4) to move laterally along the linear guide rail (9) to cover the entire photosensitive dry film wet film measurement area. Then, the optical interference component emits interference light, and the beam is split into reference light and measurement light by the beam splitter (6). The measurement light illuminates the surface of the photosensitive dry film wet film and is reflected, forming interference fringes with the reference light. Then, the photodetector (8) receives the interference fringe signal and transmits it to the PLC (12). Then, the PLC (12) receives the signal and performs filtering and data processing. It calculates the photosensitive dry film wet film thickness according to the change of interference fringes and issues motion control signal commands to adjust the position of the sensor (4). Finally, after the PLC (12) processes the data, it transmits the relevant information to the human-machine interface (13). The human-machine interface (13) receives the signal from the PLC (12) and displays the relevant data in real time.

[0067] The relevant data displayed on the human interface (13) includes measurement results (such as thickness value, uniformity analysis) and the horizontal coordinate position of the sensor (4) on the membrane surface.

[0068] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0069] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A photosensitive dry film wet film thickness measuring device based on optical interferometry, comprising: Fixed base (2), wherein the fixed base is connected to the base (1) by a bracket (3); Optical interference component, the optical interference component comprising: Light source (5), the light source (5) is fixed to the top of the bracket (3); An optical fiber is used to connect the light source (5) to the beam splitter (6). Beam splitter (6), the beam splitter (6) is located directly below the light source (5) and is connected to the bracket (3) as a whole through the fixing seat (2), and is connected to the light source (5) through the optical fiber; A reflector (7) is disposed on one side of the beam splitter (6) and its angle is finely adjusted by an adjustment mechanism; Photodetector (8), which is fixed to one side of beam splitter (6); Motion control component, the motion control component comprising: Linear guide rail (9), which is fixed to the middle of the top surface of the base (1) and extends laterally; Servo motor (10), the servo motor (10) is fixed to one end of the base (1) and driven by the linear guide rail (9); Sensor (4), the sensor (4) is located between linear guide rails (9), and the servo motor (10) drives the sensor (4) to move laterally along the linear guide rails (9); An encoder (11) is mounted above the servo motor (10); PLC (12), the PLC (12) is fixed inside the base (1) and connected to the encoder (11) and photodetector (8) respectively through signal lines; The human-machine interface (13) is embedded in the side of the base and connected to the PLC (12) via a data cable.

2. The photo-sensitive dry film wet film thickness measuring apparatus based on optical interference technology according to claim 1, wherein, The optical interference assembly also includes a dynamic compensation module, which includes a temperature sensor (14), a humidity sensor (15), and an automatic calibration unit. The temperature sensor (14) and the humidity sensor (15) are respectively embedded inside the beam splitter (6) mounting base and in close contact with it. The temperature sensor (14) and the humidity sensor (15) are connected to the PLC through signal lines.

3. The photo-sensitive dry film wet film thickness measuring apparatus based on optical interference technology according to claim 2, wherein, The automatic calibration unit includes a calibration plate (161) and a micro stepper motor (162).

4. The photo-sensitive dry film wet film thickness measuring apparatus based on optical interference technology according to claim 3, wherein, The calibration plate (161) is located in the optical path between the beam splitter (6) and the reflector (7) and can move in the vertical direction. The micro stepper motor (162) is fixed to the rear end of the beam splitter (6) mounting base and is connected to the calibration plate (161) through a transmission rod.

5. The photo-sensitive dry film wet film thickness measuring apparatus based on optical interference technology according to claim 2, wherein, The automatic calibration unit also includes a position feedback module, which includes a photoelectric encoder (171) and a limit switch (172). The photoelectric encoder (171) is fixed to the output shaft of the micro stepper motor (162) and rotates synchronously with the transmission rod. The limit switch (172) is fixed to the top of the beam splitter (6) mounting base and corresponds to the end of the movement path of the calibration piece (161). The position feedback module is connected to the PLC through a signal line to provide real-time position information of the calibration piece (161).

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