Carrier glass foreign object detection apparatus and detection method

Abstract

The present application relates to the technical field of carrier glass, in particular to a carrier glass foreign matter detection device and method. The present application comprises a detection mechanism: moving along the X direction or Y direction to detect foreign matter on the front surface of the glass; a glass conveying mechanism: an air float plate generates a gas cushion through compressed air to convey the glass thereon without being affected by friction; at the edge of the glass, guide rollers are installed to stabilize the glass to prevent it from tilting or shifting; a control mechanism: including a control mechanism that receives data collected from the detection mechanism, takes different gray images through the projection reflection of the laser, and determines the size and number of foreign matter through the judgment of the gray value. The present application can effectively improve the accuracy and speed of foreign matter detection and reduce the false detection rate. At the same time, the device also has an automatic control function, which can realize unattended detection, improve production efficiency and safety.

Description

Technical Field

[0001] This invention relates to the field of carrier glass technology, specifically to a foreign object detection device and method for carrier glass. Background Technology

[0002] With the rapid development of information technology, people's demands for information processing and communication are increasing. Against this backdrop, various digital devices and systems have sprung up like mushrooms after rain, enabling people to more conveniently obtain, process, and transmit information. Among them, the widespread application of mobile terminals has further fulfilled people's desire to access information anytime, anywhere. The carrier glass is a crucial component of display terminals, and its quality affects the final display effect.

[0003] Existing glass defect inspection equipment suffers from low detection accuracy and slow detection speed. To improve the efficiency and accuracy of foreign object detection in glass, this invention provides a novel glass foreign object detection device. For example, Chinese Patent CN101813640A discloses a foreign object inspection device and method for glass surfaces. This method uses a laser irradiation unit to irradiate foreign objects on a glass substrate in a direction perpendicular to the transport direction, thereby detecting foreign objects attached to the glass surface. Although these devices typically employ the principle of laser irradiation, in practical use, the detection accuracy and speed of these devices are affected by various factors, making it difficult for traditional equipment to accurately detect small, transparent, and low-reflectivity foreign objects, and also increasing the probability of false detections and missed detections. Summary of the Invention

[0004] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies and provide a foreign object detection device and method for carrier glass, which can effectively improve the accuracy and speed of foreign object detection and reduce the false detection rate. Simultaneously, the device also has automated control functions, enabling unattended detection and improving production efficiency and safety.

[0005] The technical solution of this invention is as follows:

[0006] A foreign object detection device for carrier glass, comprising:

[0007] The detection mechanism includes Camera I and Camera II, both of which are fixedly installed above the glass and move along the X or Y direction to detect foreign objects on the front of the glass.

[0008] Glass conveying mechanism: It consists of a series of air-floating plates, which generate an air cushion layer by compressed air so that the glass can be conveyed on it without being affected by friction; at the edge of the glass, guide rollers are installed to stabilize the glass and prevent it from tilting or shifting;

[0009] Control mechanism: This includes a control mechanism that is connected to the detection mechanism and the glass conveying mechanism. The control mechanism receives data collected from the detection mechanism, takes images of different grayscale levels through laser projection and reflection, and determines the size and quantity of foreign objects by judging the grayscale values.

[0010] Preferably, the detection mechanism further includes a lens adjustment device, which includes a motor; the position of the lens is controlled by the motor, and the lens is moved a certain distance in the direction that minimizes the focusing error.

[0011] Preferably, the detection mechanism uses an adaptive algorithm to determine the movement direction and step size of the lens, and the adaptive algorithm adopts gradient descent or genetic algorithm.

[0012] Preferably, the detection mechanism uses laser projection and reflection to detect the grayscale image of the glass; the reflectivity of foreign objects on the glass is relatively weak, and the size and quantity of particles are determined by judging the grayscale value. Foreign objects include bubbles, scratches, and stains.

[0013] Preferably, the glass conveying mechanism is provided with guide rollers at 100mm intervals along the width direction of the air flotation plate. When the testing equipment is initially set up, the height difference of the guide rollers needs to be adjusted to within 50um. The air flotation plate of the glass conveying mechanism is used to adjust the tilt of the glass in the width direction.

[0014] Another technical solution of the present invention is as follows:

[0015] A detection method for a foreign object detection device for a carrier glass plate includes the following steps:

[0016] S1. Calculate the focus error: Use camera I and camera II to acquire images of the current focus area, perform contrast enhancement and histogram equalization on the images to obtain a clear image; then calculate the focus error of the current focus area using the focus measurement method.

[0017] S2. Adjusting the lens position: The lens position is controlled by a motor, moving the lens a certain distance in the direction that minimizes the focusing error; an adaptive algorithm is used to determine the direction and step size of the lens movement.

[0018] S3, Tilt Adaptive Correction: By analyzing the glass images captured by the camera, the tilt angle and direction of the glass are automatically detected, and the glass conveying mechanism is adaptively adjusted by the control mechanism.

[0019] Preferably, step S2, adjusting the lens position includes the following sub-steps:

[0020] S21. If the height of the glass being tested changes significantly, the longer the focusing time on the glass surface, the weaker the detection capability or the more likely it is to miss a detection. The longer the focusing time, the greater the detection deviation.

[0021] S22. Normally, the height of the glass will not change drastically during transport. However, this may happen at the front end of the transport because there are gaps between the air flotation plates. When the front end of the glass transitions from one air flotation plate to another, there may be height fluctuations, and the glass may float up or sink slightly.

[0022] S23. The camera is fixed during the detection process. If the glass is tilted in the width direction, it cannot be detected smoothly due to the difference in height and focal length. To prevent the glass from tilting, guide rollers are installed at 100mm intervals between the air float plates in the width direction. During the initial setup of the equipment, the height difference of the guide rollers needs to be adjusted to within 50um.

[0023] Preferably, in step S3, the tilt adaptive correction includes the following sub-steps:

[0024] S31. Image Acquisition: Capture an image of the glass surface using a camera;

[0025] S32. Image preprocessing: Preprocess the acquired image, including denoising, grayscale conversion, and edge detection, in order to better extract glass edge information;

[0026] S33. Extract edge information: Use image processing technology to extract glass edge information from the preprocessed image;

[0027] S34. Calculate correction parameters: Calculate the glass tilt angle and direction based on the extracted edge information, and use them as correction parameters;

[0028] S35. Control Mechanism Adjustment: Based on the calculated correction parameters, the control mechanism automatically adjusts the height of the guide rollers so that the glass can be placed horizontally for subsequent inspection operations.

[0029] Preferably, in step S1, the focusing error is calculated using different colored dots to represent foreign objects. The dots have different positions and sizes, and are defined as follows:

[0030] Ultra-small spot size: 0.3um-1um;

[0031] Small dots: 1um-3um;

[0032] Midpoint: 3um-5um;

[0033] Larger sizes: 5um-10um;

[0034] Extra-large size: 10um and above;

[0035] Depending on the actual interference factors, the spot formed by the light reflected from the foreign object may differ from the actual size of the foreign object.

[0036] Preferably, in step S1, the actual interference factors of the shortfall include:

[0037] The reflectivity of the foreign object: For foreign objects that are not very reflective, the size of the imperfection will be slightly smaller than the actual foreign object.

[0038] The thickness of the glass: the thinner the glass, the greater the likelihood that foreign objects on the back will be detected;

[0039] Camera resolution: The higher the camera resolution, the smaller the foreign objects or defects on the back that it can detect, and the higher the detection accuracy.

[0040] Light source illumination conditions: The color of the light source is closer to natural light, reducing light interference and thus increasing detection accuracy.

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] The glass conveying mechanism, equipped with an air-float plate, uses guide rollers to adjust the horizontal state of the glass in the width direction, controlling focusing errors during glass inspection. A control mechanism converts the grayscale values ​​of images with different shades into the size and number of defects. By eliminating actual interference factors related to defects, the accuracy and speed of foreign object detection can be effectively improved, reducing false detection rates. Furthermore, the equipment features automated control, enabling unattended inspection and improving production efficiency and safety. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the detection device of the present invention.

[0045] Figure 2(a) is a schematic diagram of the foreign object detection principle in thick glass.

[0046] Figure 2(b) is a schematic diagram of the foreign object detection principle of thin glass.

[0047] Figure 3 This is a schematic diagram of the different detection areas of Camera I and Camera II.

[0048] Figure 4 It is a distribution diagram of the location and size of foreign objects on the glass.

[0049] Figure 5 This is a schematic diagram of the structure where deviations exist in the detection area.

[0050] Figure 6(a) is a schematic diagram of the tilt state of the glass before adaptive correction.

[0051] Figure 6(b) is a schematic diagram of the horizontal state of the glass after adaptive correction.

[0052] In the diagram: 1. Detection mechanism; 2. Air flotation plate; 3. Guide roller; 4. Glass; 5. Laser; 6. Foreign object; 7. Detection area I; 8. Detection area II; 9. Undetected area. Detailed Implementation

[0053] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0054] Example 1

[0055] like Figure 1 As shown, this embodiment provides a foreign object detection device for carrier glass, including:

[0056] Detection agency 1 includes camera I and camera II. Both camera I and camera II are fixedly installed above glass 4 and can move along the X or Y direction in order to detect foreign objects 6 on the front of glass 4.

[0057] Glass conveying mechanism: It consists of a series of air floats 2, which generate an air cushion layer by compressed air so that the glass 4 can be conveyed on it without being affected by friction; at the edge of the glass 4, guide rollers 3 are installed to stabilize the glass 4 and prevent it from tilting or shifting.

[0058] Control mechanism: Includes a control mechanism, which is connected to the detection mechanism 1 and the glass conveying mechanism respectively. The control mechanism receives data collected from the detection mechanism 1, and takes images of different grayscale levels through the projection and reflection of the laser 5. The size and quantity of foreign objects 6 are determined by judging the grayscale values.

[0059] This invention utilizes the fact that a foreign object 6 reflects light when irradiated by a laser 5, and a camera captures the reflected light to reveal the size and position of the foreign object 6.

[0060] It should be noted that the detection equipment must be installed in a clean environment to avoid detection errors caused by environmental contamination. When the carrier glass 4 flows, the laser 5 irradiates the surface of the glass 4, and the energy of the laser 5 is absorbed or reflected. The camera is located in the reflected light path of the laser 5 beam and can capture the light signal reflected back from the laser 5 beam. These light signals are processed by the camera's lens and sensor, converted into digital signals, and transmitted to the control mechanism. The control mechanism generates images based on these digital signals. These images typically use different colors to represent the location and size of defects, thus providing detailed information about the sample surface.

[0061] The present invention can classify the size into five categories: ultra-small point (0.3um-1um), small point (1um-3um), medium point (3um-5um), large point (5um-10um), and ultra-large point (above 10um). The above size classification may not be the same as the actual size of the foreign object 6.

[0062] What is detected is the size of the light reflected by foreign object 6. When foreign object 6 reflects strong light, the size of the light may be slightly larger than the actual size of the foreign object. For foreign object 6 that is less reflective, the size of the light may be slightly smaller than the actual size of the foreign object. The above mentions the possibility that the size of the light reflected from foreign object 6 may not perfectly match the actual size of the foreign object. This discrepancy is due to the different speeds of light propagation in different materials, light scattering, and other factors. When foreign object 6 reflects strong light, the light rays are focused on the surface of foreign object 6, so the size of the light may be slightly larger than the actual size of the foreign object. Conversely, if foreign object 6 is less reflective, the light rays may be absorbed or scattered, resulting in a smaller size of the light than the actual size of the foreign object.

[0063] The camera captures images using autofocus (AF) on the surface of glass 4. The device itself cannot distinguish whether the defect occurs on the surface or the back of glass 4. The result is that all light captured by the camera is considered a defect. The results of the camera capturing defects on the back of glass 4 are also displayed. The detected size of the defects on the back is proportional to the thickness of glass 4. The thinner the glass 4, the greater the likelihood of detecting foreign objects on the back. Figures 2(a) to 2(b) To further illustrate the above discussion: when using a camera to photograph a transparent object, not only its front but also its back can be seen. However, there may be foreign objects or defects on the back of the glass 4, such as bubbles, scratches, stains, etc. The thickness of the glass 4 affects the detection results: the detected size of defects on the back is smaller than the proportion of the glass 4 thickness, meaning that the thinner the glass 4, the greater the likelihood of detecting defects on the back. Therefore, the thickness of the glass 4 needs to be known before setting parameters in order to adjust the detection parameters and algorithm accordingly.

[0064] The impact of camera resolution on detection results: The higher the camera resolution, the smaller the foreign objects or defects on the back side can be detected, and the higher the detection accuracy. Therefore, during the inspection, the device selects a suitable camera and appropriate resolution to achieve higher detection accuracy.

[0065] The impact of lighting conditions on test results: Defects on the back side may be affected by lighting conditions, resulting in shadows or reflections, thus affecting the accuracy of the test results. Therefore, during testing, the device selects an appropriate lighting method and light source to reduce the impact of shadows and reflections. This device uses a ring light source to ensure that the entire test area is adequately illuminated. The light source is an LED white light source with a color temperature of approximately 5000K. This light source's color is closer to natural light, which can reduce light interference and improve the accuracy of the test.

[0066] In summary, the glass foreign object detection device of the present invention is a device that uses a laser 5 to irradiate a foreign object 6 (or defect) on the surface or back of a glass 4, and uses a camera to capture the light reflected by the foreign object 6 to reveal the foreign object 6.

[0067] Example 2

[0068] Based on Example 1, such as Figure 4 As shown, the defects can be categorized into five types based on their size: ultra-small defects, small defects, medium defects, large defects, and ultra-large defects. It should be noted that the actual size of the foreign object 6 and the magnitude of the light it reflects are not necessarily the same. When the foreign object 6 reflects strong light, the magnitude of the reflected light may be slightly larger than its actual size; conversely, when the foreign object 6 reflects weak light, the magnitude of the reflected light may be slightly smaller than its actual size.

[0069] In order to confirm the detection capability of the device, especially the ability to detect foreign objects or defects on the back side.

[0070] Based on the above principles, particles of different sizes are sprinkled onto the back of glass 4 using a specific technique. Measurements are then taken from the upper surface of glass 4 at a sensitivity of 0.3 micrometers to confirm whether these particles can be detected. The detectable particle size varies depending on the thickness of glass 4.

[0071] The particles scattered on the back side are measured from the surface of glass 4 to confirm whether the equipment can detect these back-side defects. If the particles on the back side cannot be detected, it means that the equipment cannot detect back-side defects of the corresponding size. It should be noted that when the plate thickness is thinner, the distance between the surface and the back side is shorter, and the back-side defects are more easily reflected, which may affect the detection accuracy.

[0072] Based on experiments, the approximate values ​​for particle size and thickness that this device can detect are as follows:

[0073] 0.7mm 50μm 0.5mm 20μm 0.4mm 10μm 0.3mm 5μm

[0074] The camera in the device of the invention is for online shooting, with a horizontal (X-direction) field of view of 100mm and a flow direction (Y-direction) field of view of 20µm. If light from foreign objects or defects on the back is reflected outside the camera's field of view, it will not be captured. However, the thinner the glass 4, the higher the probability that it will enter the camera's field of view.

[0075] The measurement is performed using a fixed camera, a conveying mechanism that moves glass 4 at a predetermined speed, and a mechanism for detecting defects. Since the camera is fixed, the conveying state of glass 4 has a significant impact on defect detection.

[0076] The following describes the relevant structure or system of this device:

[0077] Glass conveying mechanism: This mechanism should consist of a series of air-floating plates 2, which can generate an air cushion layer using compressed air so that the glass 4 can be conveyed on it without being affected by friction. Guide rollers 3 are installed at the edges of the glass 4 to stabilize it and prevent it from tilting or shifting.

[0078] Detection Unit 1: This unit is equipped with Camera I and Camera II. These units are located above the glass 4 and can move along the X direction to detect foreign objects 6 on the front of the glass 4.

[0079] Control Mechanism: The mechanism is also equipped with a control system that controls the glass 4 conveying system and the detection mechanism. This system can process the data collected from the detection mechanism 1, capture images of different grayscale levels through the projection and reflection of the laser 5, and determine the size and quantity of particles by judging the grayscale values.

[0080] The laser 5 used in the equipment is a helium-neon laser. The helium-neon laser can be used for defect detection in glass 4. The principle is to utilize the difference in transmittance and reflectivity of the helium-neon laser in glass 4.

[0081] A helium-neon laser with a wavelength of 632.8 nanometers is selected. This wavelength can penetrate glass 4 and can also be absorbed or reflected by glass 4. When the helium-neon laser is irradiated on the surface of glass 4, the laser 5 will penetrate glass 4 and undergo refraction, scattering, and reflection within glass 4. When laser 5 encounters defects on or inside the surface of glass 4, such as bubbles, cracks, or impurities, laser 5 will be absorbed, scattered, or reflected, forming a noticeable bright or dark spot, which is a foreign object or defect in the glass. To ensure that laser 5 can accurately irradiate the surface of glass 4, appropriate lenses and reflectors are needed to focus the laser beam.

[0082] Example 3

[0083] Based on Example 2, such as Figure 1 and 5 As shown, cameras I and II measure a 100mm width area on each side of the same glass piece 4, referred to here as one scanning unit. When the two sides are combined, a 200mm width of the same glass piece 4 is measured. After measuring one glass piece 4, the detection mechanism 1 moves 100mm along the X direction, and then measures an additional 100mm + 100mm area on the next glass piece 4. Figure 3 As shown. The orange and blue 100mm width areas are the areas detected by detection mechanisms 1 on side I and side II, respectively. After several pieces of glass 4 have flowed, the measurement results of these pieces of glass 4 are superimposed to synthesize a complete distribution map of foreign matter 6, as shown. Figure 4 (Taking a glass 4 with dimensions of 2500mm x 2200mm as an example). The detection area in the flow direction is not necessarily the length of glass 4 captured by the camera. Both camera I and camera II have acquisition sensors. When glass 4 is transported at the prescribed speed, the portion matching the dimensions can be detected. If the transport speed of glass 4 is slightly slower than the prescribed speed, the detectable range will narrow. If the transport speed of glass 4 is slightly faster than the prescribed speed, the detectable range will widen. Figure 5 To further clarify: Glass 4 is conveyed along a specified direction and detected by cameras and sensors during this process. The detection area refers to the region where the system can detect the dimensions of Glass 4; this area is not necessarily equal to the length of Glass 4 captured by the camera. If the conveying speed of Glass 4 is slower than the specified speed, the detection area will narrow because the system can only detect within the specified time. If the conveying speed of Glass 4 is faster than the specified speed, the detection area will widen because the system will have more time to detect the dimensions of Glass 4. The cameras and sensors in the Glass 4 detection system need to perform detection within the specified time. If the conveying speed of Glass 4 is slower than the specified speed, the system can only detect shorter lengths of Glass 4 within the specified time, because the system cannot detect longer lengths of Glass 4 within the specified time. For example, if the detection system is specified to detect 10 units of Glass 4 per second, but the conveying speed of Glass 4 is only 5 units per second, then the system can only detect 5 units of Glass 4 per second. Therefore, if the conveying speed of Glass 4 is slower than the specified speed, the detection area will narrow.

[0084] like Figure 5 As shown, deviations in the detection area may cause problems such as missed detections and false detections. To solve these problems, the device is equipped with multiple solutions to ensure high precision and high reliability.

[0085] Detection area I (7) is the location of camera I; detection area II (8) is the location of camera II; undetected area 9 is the location outside the detection area.

[0086] I. Feedback Mechanism: Establish a feedback mechanism to analyze and process the results of each test, and promptly report any deviations in the test area so that corrections can be made in a timely manner.

[0087] II. Adaptive Algorithm: An adaptive algorithm is used to dynamically adjust the position and size parameters of the detection area based on feedback from the detection results, ensuring the accuracy of the detection area.

[0088] III. Correction Algorithm: The correction algorithm is used to correct and compensate for the detection results, so as to eliminate the influence of the detection area deviation and ensure the accuracy and consistency of the detection results.

[0089] This inspection equipment detects defects by automatically focusing a camera on the surface of glass 4. AF (autofocus) is performed after glass 4 is brought in.

[0090] Auto focus (AF) is a common function in cameras, camcorders, and other devices. It is used to adjust the focal length of the lens when shooting objects at different distances, so that the subject is clearly presented on the image plane.

[0091] This invention provides a detection method for a foreign object detection device for a carrier glass plate, comprising the following steps:

[0092] S1. Calculate the focus error: Use camera I and camera II to acquire images of the current focus area, perform contrast enhancement and histogram equalization on the images to obtain a clear image; then calculate the focus error of the current focus area using the focus measurement method.

[0093] S2. Adjusting the lens position: The lens position is controlled by a motor, moving the lens a certain distance in the direction that minimizes the focusing error; an adaptive algorithm is used to determine the direction and step size of the lens movement.

[0094] S3, Tilt Adaptive Correction: By analyzing the image of glass 4 captured by the camera, the tilt angle and direction of glass 4 are automatically detected, and the glass conveying mechanism is adaptively adjusted by the control mechanism.

[0095] Preferably, step S2, adjusting the lens position includes the following sub-steps:

[0096] S21. If the height of the glass 4 being tested changes greatly, the longer the focusing time on the surface of the glass 4 is, the weaker the detection capability will be, or a missed detection will occur. The longer the focusing time is, the greater the detection deviation will be.

[0097] S22. Normally, the height of glass 4 will not change drastically during transport. However, this may happen at the front end of the transport because there are gaps between the air flotation plates 2. When the front end of glass 4 transitions from one air flotation plate 2 to another, there may be height fluctuations, and glass 4 may float up or sink slightly.

[0098] S23. During detection, the camera is fixed. If the glass 4 is tilted in the width direction, it cannot be detected smoothly due to differences in height and focal length. To prevent the glass 4 from tilting, guide rollers 3 are installed at 100mm intervals along the width direction of the air float plate 2. During the initial setup of the equipment, the height difference of the guide rollers 3 needs to be adjusted to within 50µm. Figures 6(a) to 6(b) .

[0099] Preferably, in step S3, the tilt adaptive correction includes the following sub-steps:

[0100] S31. Image acquisition: Capture an image of the glass surface 4 using a camera;

[0101] S32. Image preprocessing: Preprocess the acquired image, including denoising, grayscale conversion, and edge detection, in order to better extract the edge information of glass 4;

[0102] S33. Extract edge information: Use image processing technology to extract the edge information of glass 4 from the preprocessed image;

[0103] S34. Calculate correction parameters: Based on the extracted edge information, calculate the tilt angle and direction of glass 4, and use them as correction parameters;

[0104] S35. Control mechanism adjustment: Based on the calculated correction parameters, the control mechanism automatically adjusts the height of the guide roller 3 so that the glass 4 can be placed horizontally for subsequent inspection operations.

[0105] Preferably, in step S1, the focusing error is calculated using different colored dots to represent foreign objects 6. The dots are set with different positions and sizes, and are defined as follows:

[0106] Ultra-small spot size: 0.3um-1um;

[0107] Small dots: 1um-3um;

[0108] Midpoint: 3um-5um;

[0109] Larger sizes: 5um-10um;

[0110] Extra-large size: 10um and above;

[0111] Depending on the actual interference factors, the defect formed by the reflected light from foreign object 6 differs from the actual size of the foreign object.

[0112] Preferably, in step S1, the actual interference factors of the shortfall include:

[0113] Foreign object reflectivity: Foreign object 6, which is not very reflective, will have a smaller size than the actual foreign object;

[0114] The thickness of the glass: the thinner the glass, the greater the possibility of detecting foreign objects on the back.

[0115] Camera resolution: The higher the camera resolution, the smaller the foreign objects or defects on the back can be detected, and the higher the detection accuracy.

[0116] Light source illumination conditions: The color of the light source is closer to natural light, reducing light interference and thus increasing detection accuracy.

[0117] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the invention should also be covered within the protection scope of the invention. Therefore, the protection scope of the invention should be determined by the scope of the claims.

Claims

1. A detection method for a foreign object detection device for a carrier glass substrate, the carrier glass substrate foreign object detection device comprising: The detection mechanism (1) includes camera I and camera II, both of which are fixedly installed above the glass (4) and move along the X or Y direction to detect foreign objects (6) on the front of the glass (4); the glass conveying mechanism consists of a series of air-floating plates (2), which generate a gas cushion layer by compressed air so that the glass (4) can be conveyed on it without being affected by friction; at the edge of the glass (4), guide rollers (3) are installed to stabilize the glass (4) and prevent it from tilting or shifting; the control mechanism is connected to the detection mechanism (1) and the glass conveying mechanism respectively. The control mechanism receives the data collected from the detection mechanism (1), takes images of different gray levels by the projection and reflection of the laser (5), and determines the size and number of foreign objects (6) by judging the gray level value. The mechanism is characterized by including the following steps: S1. Calculate the focus error: Use camera I and camera II to acquire images of the current focus area, perform contrast enhancement and histogram equalization on the images to obtain a clear image; then calculate the focus error of the current focus area using the focus measurement method. S2. Adjusting the lens position: The lens position is controlled by a motor, moving the lens a certain distance in the direction that minimizes the focusing error; an adaptive algorithm is used to determine the direction and step size of the lens movement. S3, Tilt Adaptive Correction: By analyzing the image of the glass (4) captured by the camera, the tilt angle and direction of the glass (4) are automatically detected, and the glass conveying mechanism is adaptively adjusted by the control mechanism. In step S3, the tilt adaptive correction includes the following sub-steps: S31. Image acquisition: Image of the glass (4) surface captured by camera; S32, Image preprocessing: The acquired image is preprocessed, including noise reduction, grayscale conversion, and edge detection operations, in order to better extract the glass (4) edge information; S33. Extract edge information: Use image processing technology to extract the glass (4) edge information from the preprocessed image; S34. Calculate the correction parameters: Based on the extracted edge information, calculate the tilt angle and direction of the glass (4) and use them as correction parameters. S35. Control mechanism adjustment: Based on the calculated correction parameters, the control mechanism automatically adjusts the height of the guide roller (3) so that the glass (4) can be placed horizontally for subsequent testing operations.

2. The detection method of the foreign object detection device for carrier glass as described in claim 1, characterized in that, In step S2, adjusting the lens position includes the following sub-steps: S21. If the height of the glass (4) being tested changes greatly, the longer the focusing time on the surface of the glass (4) is, the weaker the detection capability will be, or a missed detection will occur. The longer the focusing time, the greater the detection deviation. S22. Normally, the height of the glass (4) will not change drastically during transport. However, this situation may occur at the front end of the transport because there are gaps between the air flotation plates (2). When the front end of the glass (4) transitions from one air flotation plate (2) to another, there may be height fluctuations, and the glass (4) may float up or sink slightly. S23. When the device is used for testing, the camera is fixed. If the glass (4) is tilted in the width direction, it cannot be detected smoothly because of the different heights and focal lengths. To prevent the glass (4) from tilting, guide rollers (3) are set at 100mm intervals between the air floats (2) in the width direction. When the device is initially set up, the height difference of the guide rollers (3) needs to be adjusted to within 50um.

3. The detection method of the foreign object detection device for carrier glass as described in claim 2, characterized in that, In step S1, the focusing error is calculated by using different colored dots to represent foreign objects (6). The dots are set with different positions and sizes and are defined as follows: Ultra-small spot size: 0.3um-1um; Small dots: 1um-3um; Midpoint: 3um-5um; Larger sizes: 5um-10um; Extra-large size: 10um and above; Depending on the actual interference factors, the defect formed by the light reflected by the foreign object (6) differs from the actual size of the foreign object (6).

4. The detection method of the foreign object detection device for carrier glass as described in claim 3, characterized in that, In step S1, the actual interference factors of the underperforming point include: The reflectivity of the foreign object: The size of the spot of the less reflective foreign object (6) will be smaller than that of the actual foreign object (6); The thickness of the glass: the thinner the glass (4), the greater the possibility of detecting foreign objects (6) on the back; Camera resolution: The higher the camera resolution, the smaller the foreign objects (6) or defects on the back that can be detected, and the higher the detection accuracy. Light source illumination conditions: The color of the light source is closer to natural light, reducing light interference and thus increasing detection accuracy.

Images