CN110618138B - A method for detecting defects in a display screen using the principle of equal thickness interference - Google Patents

Abstract

The invention discloses a system and a method for detecting defects in a display screen by using an equal-thickness interference principle, and belongs to the technical field of optical interference detection. According to the invention, an air wedge is formed between the glass slide to be detected and the flat glass slide, parallel light penetrates through the air wedge to generate interference fringes, when a defect or impurity exists in the glass slide to be detected, the interference fringes are distorted, the fringe stage number and the fringe width are respectively calculated in the x direction and the y direction to obtain the specific position coordinate of the defect, and then the specific position coordinate is subjected to subsequent processing and cutting, so that higher detection precision can be realized, the operation is simple and convenient, the missing detection of the defect or impurity is effectively prevented, and the complete defect-free glass display screen is obtained.

Description

A method for detecting defects in a display screen using the principle of equal thickness interference

technical field

The invention belongs to the technical field of light detection, and more particularly, relates to a system and method for detecting defects in a display screen by using the principle of equal thickness interference.

Background technique

In order to let users intuitively know the running status of electronic devices, or to allow users to conveniently control electronic devices, electronic devices are usually equipped with different display screens. The quality of the display screen is related to the quality of the original glass sheet. There are various needs. The original glass sheet is re-cut after impurity detection, and then a series of processing and processing can be performed to obtain a display screen that meets the requirements. In addition, impurities may remain on the display screen during the manufacturing and installation of the equipment, which will affect the quality of the display screen. For example, when filming on the display screen, impurities such as dust and glue will be left behind. Therefore, after the display screen is manufactured, it may be After the display screen is installed on the device, the quality of the display screen needs to be tested. The staff visually detects whether there are obvious impurities on the display screen of the product. It is difficult to detect some subtle impurities, and the detection results are not accurate. In addition, when working for a long time, the human eye will have visual fatigue, thereby increasing the number of missed inspections. Risks, in addition, manual detection also greatly increases the cost.

In order to improve the detection efficiency and quality, the computer image detection method is used to detect impurities in the prior art. For example, the patent application number: 2018215036160, the application date: September 13, 2018, the name of the invention and creation is: an online detection of impurities in glass original sheets The application discloses a device for on-line detection of impurities in a glass original, including a glass original transmission table for placing the glass original to be detected, a glass original for discovering impurities in the glass original and obtaining the specific coordinates of the impurities. A low-power observation linear array, a horizontal sliding table that can be horizontally displaced, a computer sliding table control module for receiving the coordinate information of impurities obtained by the low-power observation linear array and controlling the displacement of the horizontal sliding table to the position facing the impurities, and a horizontal The contour recognition component fixedly connected to the sliding table and the computer image processing module connected with the contour recognition component; the contour recognition component is used to obtain the contour image data of the impurities of the original glass sheet found by the low magnification observation line array, and the computer image processing module is used for Obtain the contour image data obtained by the contour recognition component and determine the contour of the characteristic defect type; the device is simple and convenient to operate and has a good detection effect, but it not only needs to detect the presence or absence of impurities, but also the position size and contour shape of the impurities. The detection process There are many processes.

Another example is the patent application number: 2018106457926, the application date: June 21, 2018, and the name of the invention is: detection method and device for impurities in a display screen. The detection method of the application includes: obtaining the minimum circumscribed rectangle of the target display screen, Obtaining the first target image: Obtaining noise information of the first target image, where the noise information at least includes the size of the noise and the position of the noise in the first target image, the type of the noise information at least includes impurity information and background information, and the impurity information at least Including dust information, the background information is the area outside the target display screen in the minimum circumscribed rectangle: remove the noise information in the area where the four corners of the first image are located from the noise information of the first target image, and obtain the first target information: based on the first target image. A target information determines the impurity information of the target display screen. This solution only detects impurities on the rectangular display screen with rounded corners. Although the effect of detecting impurities in the display screen with rounded corners is improved, the noise information in the minimum circumscribed rectangular image containing the target display screen needs to be obtained first. The surrounding of the display screen is the background, and then the noise information in the area where the four corners are located is removed. There are many detection steps, and the detection is mainly carried out for the display screen with relatively small size.

SUMMARY OF THE INVENTION

1. The technical problem to be solved by the invention

The invention provides a system and method for detecting defects in a display screen using the principle of equal-thickness interference. Taking the width of equal-thickness interference fringes of light as the unit, the specific position coordinates of the defects are obtained by calculating the fringe series and the fringe width, and then the Subsequent processing and tailoring can achieve higher detection accuracy, effectively prevent missed detection of defects or impurities, and obtain a complete and defect-free glass display.

2. Technical solutions

For achieving the above object, the technical scheme provided by the invention is:

A method for detecting defects in a display screen using the principle of equal thickness interference, comprising the following steps:

Step 1: Place the flat glass slide on the measuring platform, and set a certain thickness of the clip between the flat glass slide and the test glass to form an air wedge, and the flat glass slide, the test glass and the clip are formed between an interferometric system, the interferometric system is provided with a scanning system;

Step 2: adjust the position of the light source part and the imaging part by adjusting the scanning bracket in the scanning system, so that the light emitted from the light source part scans the glass to be tested in the direction of increasing the thickness of the air wedge and generates interference fringes;

Step 3: During the scanning process, the interference fringes at the defects of the glass to be tested are abnormal, and the lateral distance x from the defect corresponding to the abnormal fringes to the edge of the glass to be tested is calculated by the optical microscope module. Camera part connection;

Step 4: Take out the clamping block and place it on the adjacent side of the glass to be tested to form another air wedge. Repeat steps 2 and 3 to obtain the longitudinal distance y from the defect corresponding to the abnormal streak to the edge of the glass to be tested.

As a further improvement of the present invention, the stripe series n and stripe width l ₀ from zero-order stripes to abnormal stripes are calculated, and the distance from the defect corresponding to the abnormal stripe to the edge of the glass to be tested is nl ₀ .

As a further improvement of the present invention, the coordinates of one level of normal stripes are defined as x _k , and the coordinates of 20 levels of normal stripes are defined as x _k+20 , and the total width of the 20 levels of normal stripes is measured as |x _k -x _k+20 |, the calculated width of a single stripe is l ₀ =|x _k -x _k+20 |/20.

As a further improvement of the present invention, the fringe counter in the optical microscope module is used to measure the fringe order n from the zero-order fringes at the edges to the corresponding distortion fringes at the defects.

As a further improvement of the present invention, the height h of the clamping block is set according to the length a of the glass slide to be tested, and h/a=0.005-0.015.

A system for detecting defects in a display screen using the principle of equal thickness interference of the present invention includes a scanning system, an interference system and an optical microscope module, the scanning system includes a scanning support, a light source part and a camera part connected to the scanning support , the outgoing light of the light source part is used to illuminate the interference system to generate interference fringes, the interference system includes a glass to be tested and a flat glass placed at the bottom of the glass to be tested, the glass to be tested and the A clamping block is arranged between the flat glass slides to form an air wedge, the scanning bracket is used to adjust the outgoing light and scan the glass slide to be tested horizontally and vertically, and the optical microscope module is connected with the camera part to observe and record the interference fringes changes.

As a further improvement of the present invention, the scanning support includes a horizontally arranged sliding support rod and a vertically arranged telescopic support rod, the bottom of the telescopic support rod is provided with a fixed rod, and the fixed rod is used to install the light source part and the camera. In part, the telescopic strut moves horizontally along the sliding strut to make the outgoing light scan the glass to be tested laterally.

As a further improvement of the present invention, the sliding strut is connected to the guide rail, and the sliding strut along the sliding direction of the guide rail is perpendicular to the moving direction of the telescopic strut along the sliding strut, so as to realize the longitudinal direction of the glass to be tested by the emitted light. scanning.

As a further improvement of the present invention, the light source part is fixedly connected to the fixing rod through a first link, and the imaging part is fixedly connected to the fixing rod through a second link.

As a further improvement of the present invention, a displacement sensor is also provided in the sliding support rod and the telescopic support rod.

3. Beneficial effects

Adopting the technical scheme provided by the present invention, compared with the prior art, has the following remarkable effects:

(1) A method for detecting defects in a display screen using the principle of equal thickness interference of the present invention, an air wedge is formed between the glass slide to be tested and the flat glass slide, and parallel light passes through the air wedge to generate interference fringes. When there are defects or impurities in the glass slide, the interference fringes are distorted. Calculate the fringe series and fringe width in the x and y directions to obtain the specific position coordinates of the defects, and then perform subsequent processing and tailoring to achieve higher detection accuracy. The operation is simple and convenient.

(2) In a method of the present invention for detecting defects in a display screen using the principle of equal thickness interference, the height h of the clamping block is set according to the length a of the glass to be tested, h/a=0.005-0.015, which is beneficial to obtain a sufficient number of Bright and dark stripes, with small stripe width and scattered arrangement, are conducive to the observation and recording of the optical microscope module and reduce the measurement error.

(3) A system of the present invention for detecting defects in a display screen using the principle of equal-thickness interference, the light source part and the camera part are respectively fixedly connected to a fixed rod through a connecting rod, and the fixed rod is slidably connected to a sliding support rod through a telescopic support rod, Adjusting the sliding support rod and the telescopic support rod enables the parallel beam to perform a comprehensive scanning inspection of the glass to be tested, which can effectively prevent the missed inspection of defects or impurities, and obtain a complete and defect-free glass display with high inspection efficiency.

(4) A system of the present invention for detecting defects in a display screen using the principle of equal-thickness interference. A displacement sensor is also provided in the sliding support rod and the telescopic support rod. The displacement sensor can be used to assist in judging the coordinates of defects in the display screen, so that the detection The stability of the process is guaranteed.

Description of drawings

1 is a schematic structural diagram of a system for detecting defects in a display screen using the principle of equal-thickness interference according to the present invention;

Fig. 2 is the structural representation of the light source part in the present invention;

FIG. 3 is a schematic diagram of the plane coordinates of the defect of the display screen in the present invention.

FIG. 4 is a schematic plan view of the definition of fringe progression in the present invention.

Reference signs: 1-1, sliding support rod; 1-2, telescopic support rod; 1-3, fixed rod; 2-1, light source housing; 2-2, fixed seat; 2-3, first connecting rod; 2-4, laser; 2-5, fixed frame; 2-6, short focal length lens; 2-7, long focal length lens; 3-1, camera lens; 3-2, eyepiece; 3-3, lens barrel; 3 -4, Objective lens; 3-5, Reflector; 3-6, Second connecting rod; 4-1, Glass to be tested; 4-2, Flat glass; 4-3, Interference fringes; 4-4, Pad piece; 4-5, clamping block.

Detailed ways

In order to further understand the content of the present invention, the present invention will be described in detail with reference to the accompanying drawings and embodiments.

Example 1

1 to 3, a system for detecting defects in a display screen using the principle of equal thickness interference in this embodiment includes a scanning system, an interference system, and an optical microscope module. The scanning system includes a scanning bracket and a light source connected to the scanning bracket. part and the camera part, the outgoing light of the light source part is used to illuminate the interference system to generate interference fringes. The interference system includes the glass slide 4-1 to be tested and the flat glass slide 4-2 placed at the bottom of the glass slide 4-1 to be tested. A clamping block 4-5 is set between the glass slide 4-1 and the flat glass slide 4-2 to form an air wedge. The scanning bracket is used to adjust the outgoing light and scan the glass slide 4-1 to be tested horizontally and vertically. The imaging part is connected to observe and record the changes of the interference fringes.

Further, in this embodiment, the scanning support includes a horizontally arranged sliding support rod 1-1 and a vertically arranged telescopic support rod 1-2, the bottom of the telescopic support rod 1-2 is provided with a fixed rod 1-3, and the fixed rod 1- 3 is used to install the light source part and the imaging part, and the light source part and the imaging part are arranged side by side. Scanning; the sliding support rod 1-1 is connected with the guide rail, and the sliding support rod 1-1 is perpendicular to the sliding direction of the telescopic support rod 1-2 along the moving direction of the sliding support rod 1-1 along the guide rail, so as to realize the emission light of the glass to be tested 4- In the longitudinal scan of 1, the horizontal and vertical directions are respectively parallel to the two adjacent sides of the glass slide 4-1 to be tested, and the light ray scans and detects the interference system along the direction of increasing the thickness of the air wedge.

Specifically, in this embodiment, the light source part includes a light source housing 2-1, and the light source housing 2-1 is provided with a laser 2-4, a short focal length lens 2-6 and a long focal length lens 2-7, and the light emitted by the laser 2-4 Passing through the short focal length lens 2-6 and the long focal length lens 2-7 in turn, the parallel light with the enlarged spot diameter is obtained; the imaging part includes the imaging lens 3-1, the eyepiece 3-2, the lens barrel 3- 3 and the objective lens 3-4, the reflection sheet 3-5 is inclined and arranged at the bottom of the objective lens 3-4, and the inclination angle is 45°, so that the parallel light is irradiated on the reflection sheet 3-5 of the imaging part, and the reflection sheet 3-5 will be a The beam of parallel light is reflected to the interferometric system at the bottom to produce interference fringes. In this embodiment, an automatic focusing system is arranged in the imaging part, and the automatic focusing system is used to control the telescopic displacement of the telescopic struts 1-2, so as to obtain the best focusing state of the observation field.

The detection principle is as follows. In this embodiment, two glass display screens are stacked together, one end is in contact, and the other end is sandwiched with clamping blocks 4-5. A wedge-shaped air film is formed between the two glass screens. When parallel light illuminates the interference system , interference fringes of equal thickness will be generated on the upper surface of the air film, and the interference fringes are parallel fringes with equal width and equal spacing, and alternating light and dark. When there are defects or impurities in the upper glass slide 4-1 to be tested, the interference fringes will be distorted. The shape of the distortion is related to the shape of the internal defects of the display screen. In this embodiment, the optical microscope module can record the corresponding defects of the distortion fringes. Defects or impurities in the display screen can be detected through the change of interference fringes, which can prevent missed detection and improve detection accuracy.

The solution also provides a method for detecting defects in a display screen using the principle of equal thickness interference, including the following steps:

Step 1: Place the flat glass slide 4-2 on the measuring platform, set a certain thickness of the clip 4-5 between the flat glass slide 4-2 and the glass slide 4-1 to be tested to form an air split, and flatten the glass slide 4. -2. An interference system is formed between the glass slide 4-1 to be tested and the clamping block 4-5, and a scanning system is arranged on the interference system;

Step 2: adjust the position of the light source part and the imaging part by adjusting the scanning bracket in the scanning system, so that the light emitted from the light source part scans the glass slide 4-1 to be tested and generates interference fringes along the direction in which the thickness of the air wedge increases;

Step 3: During the scanning process, the interference fringes at the defects of the glass slide 4-1 to be tested are abnormal. The optical microscope module calculates the lateral distance x from the defect corresponding to the abnormal fringes to the edge of the glass slide 4-1 to be tested. The connection of the camera part in the scanning system;

Step 4: Take out the clamping block 4-5 and place it on the adjacent side of the glass to be tested 4-1 to form another air wedge. Repeat steps 2 and 3 to obtain the abnormal stripe corresponding to the defect to the glass to be tested 4. -1 The longitudinal distance y of the edge.

Theoretically speaking, the parallel light on the glass slide 4-1 to be tested forms interference fringes 4-3 through equal thickness interference, the laser wavelength λ is known, and the distance between two adjacent plaintext or dark fringes is half wavelength λ/2, When the thickness of the clips 4-5 used to generate the air wedge is 10mm, the thickness of the wedge-shaped air film corresponding to each additional stripe increases by λ/2. Generally, the shape of the uncut glass display screen is a side length a=2m. Square, for a laser with a wavelength λ of 532 nm, the number of fringes generated is N=h/(λ/2)=37593, and the generated wedge-point interference fringes of equal thickness are bright and dark, and have equal width and equal spacing. Or impurities will produce distortion, and the calculation formula of the width of the interference fringes is w=a/N=0.0532mm.

It can be seen that the calculation of the stripe width is related to the size of the uncut display screen and the thickness of the air clamps 4-5. The width of the stripes will cause a large error; on the other hand, since the present invention needs to locate the specific position of the defect, at least the distance from the defect to the two adjacent sides of the display screen, it is necessary to move the position of the clamping blocks 4-5 to form Two air wedges in different directions are used to detect the two-dimensional coordinates of the defects of the display screen respectively, and the height of the clamping blocks 4-5 is small, so it cannot be guaranteed that the positions of the two front and rear are the same, and the number of stripes formed is also different. The same formula is obviously not accurate enough to calculate the stripe widths produced by the two air wedges.

Specifically in this embodiment, a clamping block 4-5 is set between the glass slide 4-1 to be tested and the flat glass slide 4-2 placed at the bottom to form an air wedge. At this time, by adjusting the telescopic strut 1-2, the Move horizontally along the sliding strut 1-1, and the parallel light scans laterally along the direction of the increase of the thickness of the wedge tip, and the interference fringes at the defect are distorted. n and the stripe width l ₀ , the distance from the defect corresponding to the abnormal stripe to the edge of the glass slide 4-1 to be tested is nl ₀ . The calculation process of stripe width is as follows: choose one level of normal stripes to define its coordinates as x _k , then count 20 levels of normal stripes to define its coordinates as x _k+20 , measure the total width of 20 levels of normal stripes as |x _k -x _{k +20} |, the first-order stripe width is calculated as l ₀ =|x _k -x _k+20 |/20. Since the interference fringes of equal thickness are alternately bright and dark, and have equal width and equal spacing, the detection accuracy can be improved by calculating the average width of the 20-level normal fringes to calculate the width of a single fringe. The interference fringes will be distorted in places with defects or impurities. Use the fringe counter in the optical microscope module to measure the fringe series n from the zero-order fringes on the edge to the corresponding distortion fringes at the defect, then the distance between the abnormal fringes corresponding to the defect and the edge of the glass 4-1 to be tested is X=nl ₀ =n |x _k -x _k+20 |/20.

In this embodiment, after the lateral scanning of the interference system is completed, the clamping block 4-5 is taken out and placed on the adjacent side of the glass 4-1 to be tested to form another air wedge, and the sliding support rod 1-1 is connected with the guide rail to make The reflected light from the imaging part is scanned longitudinally along the surface of the glass to be tested 4-1. According to the same method, the distance from the defect to the adjacent side of the display screen can be obtained, and the longitudinal coordinate y of the defect in the display screen can be obtained. Referring to Figure 3, by measuring the distance from the defect to the edge of the glass display in the x and y directions, the plane position coordinates of impurities or defects can be located. When cutting the display, the impurities can be avoided to obtain a complete and defect-free glass display. . For the coordinate positioning of defects, the display screen can be scanned horizontally and vertically at one time. After scanning, all the defect coordinates in the display screen can be obtained, and reasonable cutting is carried out according to each defect coordinate to improve the processing efficiency.

In the prior art, defects are detected by taking photos, scanning and observing the photos, or by two-dimensional scanning of a CCD camera and determining defects or impurities by the mechanical coordinates of the camera. Compared with the above methods, the detection method of this embodiment is more accurate. The embodiment is based on the principle of equal thickness interference and takes the width of the interference fringes as the unit to accurately check and measure the specific coordinates of each impurity or defect in the display screen, which greatly improves the detection efficiency and detection accuracy.

Example 2

A method for detecting defects in a display screen using the principle of equal thickness interference in this embodiment is basically the same as that in Embodiment 1. Further, in this embodiment, a clamping block 4-5 is set according to the length a of the glass slide 4-1 to be tested. The height h, h/a=0.005～0.015, specifically in this embodiment, the glass slide 4-1 to be tested is a square with a side length of 2m. According to the above formula, the height of the clamping block 4-5 is calculated to be 10mm～30mm. The height of the middle clamping block 4-5 is 30 mm, that is, the maximum thickness of the entire air wedge is 30 mm. In this embodiment, the laser 2-4 is a green laser with a wavelength of 532 nm.

Since the width of the fringes decreases proportionally with the increase of the thickness of the clamping blocks 4-5, in order to make the interference fringes formed by the interference system easy to observe and calculate, the height of the clamping blocks 4-5 in this embodiment should not be too large or too small. -5 When the height is small, it is not easy to pick and place, which will make the gap between the air wedges formed twice before and after is large, and the number of formed stripes will decrease and the width of the stripes will increase, thereby increasing the calculation error of the subsequent process; the height of the clamping block 4-5 When the width is larger, the width of the formed stripes is reduced. Although it is beneficial to reduce the calculation error, the bright and dark stripes are densely arranged, making it difficult to observe and record. Therefore, the height h of the clamping block 4-5 in this embodiment is reasonably set according to the length a of the glass slide 4-1 to be tested, which is conducive to obtaining a sufficient number of light and dark stripes, and the stripe width is small and the arrangement is scattered, which is conducive to the optical microscope module records to reduce measurement errors.

Example 3

In this embodiment, a system for detecting defects in a display screen using the principle of equal thickness interference is basically the same in structure as in Embodiment 1. Further, in this embodiment, the light source part is fixed with the first connecting rod 2-3 and the fixing rod 1-3 Connection, the camera part is fixedly connected with the fixing rod 1-3 through the second connecting rod 3-6. Due to the large size of the glass display screen, if an external fixed light source is used to scan and detect a square display screen with a size of about 2m, the required fixed light source structure is large, and energy is consumed and wasted. In this embodiment, the fixed rod 1-3 can move horizontally along the sliding rod 1-1 along with the telescopic rod 1-2, and the relative position of the light source part and the imaging part remains unchanged, so that the synchronous movement of the light source part and the imaging part can be realized, and the light source part and the imaging part can move synchronously. Some can provide parallel light with stable beam. The interference fringes formed by the parallel light through the interference system are exactly the same as the effect of the external large light source, which not only saves energy, but also reduces light pollution.

Example 4

In this embodiment, a system for detecting defects in a display screen using the principle of equal thickness interference is basically the same as the first embodiment. There is a displacement sensor, and the telescopic struts 1-2 contain power lines and signal lines. The displacement sensor can be used to record the mechanical coordinates of the camera part to assist in judging the position of the distortion fringe corresponding to the defect. Due to the return error of the displacement sensor, the sensitivity and stability are average, and it is not accurate enough to use the displacement sensor alone to determine the defect position. Especially when the circuit fails, the displacement sensor cannot detect the displacement of the support rod, and cannot judge the position coordinates of the camera part.

In this embodiment, the position of the imaging part is determined by the mechanical coordinates calculated by the displacement sensor, and the position of the imaging part is compared with the defect coordinates measured by the optical interference principle. If the calculated mechanical coordinate gap is too large, the staff will be prompted to scan and detect the part again. Therefore, in this embodiment, the displacement sensor installed in the support rod can be used to assist in judging the coordinates of defects in the display screen, so that the stability of the detection process can be guaranteed. The width of the interference fringes is taken as the unit, and the precise position of the defects or impurities inside the display screen is detected, and then eliminated by the subsequent cutting process. The detection system of this embodiment has a simple structure, convenient operation, high detection efficiency, and good detection effect.

In addition, in this embodiment, the size of the flat glass slide 4-2 and the glass slide 4-1 to be measured are larger, and spacers 4-4 are placed at the bottoms of both ends of the flat glass slide 4-2, and the spacers 4-4 are placed on the measuring platform so that the display screen can be placed smoothly and prevent the surface of the flat glass 4-2 from being worn or contaminated.

The above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The recorded technical solutions are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (1)

1. A method for detecting defects in a display screen by using an equal thickness interference principle is characterized by comprising the following steps: the system for detecting the defects comprises a scanning system, an interference system and an optical microscopic module, wherein the scanning system comprises a scanning support, a light source part and a camera part, the light source part and the camera part are connected with the scanning support, emergent light of the light source part is used for irradiating the interference system to generate interference fringes, the interference system comprises a slide to be detected (4-1) and a flat slide (4-2) placed at the bottom of the slide to be detected (4-1), a clamping block (4-5) is arranged between the slide to be detected (4-1) and the flat slide (4-2) to form an air wedge, the scanning support is used for adjusting the emergent light and transversely and longitudinally scanning the slide to be detected (4-1), and the optical microscopic module is connected with the camera part to observe and record the change condition of the interference fringes;

the scanning support comprises a sliding support rod (1-1) arranged horizontally and a telescopic support rod (1-2) arranged vertically, a fixing rod (1-3) is arranged at the bottom of the telescopic support rod (1-2), the fixing rod (1-3) is used for installing a light source part and a camera part, and the telescopic support rod (1-2) horizontally moves along the sliding support rod (1-1) to enable emergent light to transversely scan a slide (4-1) to be detected;

the sliding support rod (1-1) is connected with the guide rail, and the sliding support rod (1-1) is perpendicular to the telescopic support rod (1-2) along the moving direction of the sliding support rod (1-1) along the sliding direction of the guide rail so as to realize the longitudinal scanning of emergent light on the slide (4-1) to be detected;

the light source part is fixedly connected with the fixing rod (1-3) through a first connecting rod (2-3), and the camera shooting part is fixedly connected with the fixing rod (1-3) through a second connecting rod (3-6);

displacement sensors are arranged in the sliding support rod (1-1) and the telescopic support rod (1-2);

setting the height h of the clamping block (4-5) according to the length a of the slide (4-1) to be detected, wherein h/a is 0.005-0.015;

the defect detection comprises the following steps:

the method comprises the following steps: the method comprises the following steps that a flat glass slide (4-2) is placed on a measuring platform, a clamping block (4-5) with a certain thickness is arranged between the flat glass slide (4-2) and a glass slide to be measured (4-1) to form an air wedge, an interference system is formed among the flat glass slide (4-2), the glass slide to be measured (4-1) and the clamping block (4-5), and a scanning system is arranged on the interference system;

step two: the positions of a light source part and a camera part are adjusted by adjusting a scanning bracket in a scanning system, so that emergent light of the light source part scans a slide to be tested (4-1) along the direction of increasing the thickness of an air wedge and generates interference fringes;

step three: the interference fringes at the defect part of the slide (4-1) to be detected are abnormal in the scanning process, the transverse distance x from the defect part corresponding to the abnormal fringes to the edge of the slide (4-1) to be detected is calculated through an optical microscope module, and the optical microscope module is connected with a camera shooting part in a scanning system;

step four: taking out the clamping block (4-5), placing the clamping block on the adjacent side edge of the slide (4-1) to be detected to form another air wedge, and repeating the second step and the third step to obtain the longitudinal distance y from the defect position corresponding to the abnormal stripe to the edge of the slide (4-1) to be detected;

calculating the fringe level n and the fringe width l from the zero-order fringe to the abnormal fringe₀Obtaining the distance nl from the corresponding defect of the abnormal stripe to the edge of the glass sheet (4-1) to be detected₀；

Optionally defining a primary normal stripe with x as its coordinate_kAnd defining the coordinate of the normal stripe of the next 20 levels as x_k+20Measure the total width of 20 normal stripes as | x_k-x_k+20L, calculating the width of the first-level stripe as l₀＝|x_k-x_k+20|/20；

And measuring the fringe order n from the edge zero-order fringe to the corresponding distortion fringe at the defect by using a fringe counter in the optical microscope module.

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