Line-light combination light path defect detection method based on turnover line prism

Abstract

The invention relates to a line-light combined light path defect detection method based on a turnover line prism, which comprises the following steps: S1, product positioning and turnover: sucking a turnover line of a mobile phone display screen through a mechanism turnover device, and turning the turnover line to a set angle; s2, light source triggering and imaging: starting a narrow-surface line light source, and performing fixed shooting imaging in cooperation with an area-array camera; wherein the light source is a narrow-face line light source, and it is ensured that light rays cover the whole wire arrangement area; the light is diffused to the triangular prism through the surface of the inverted flat cable, and the prism reflects to adjust the light path direction to the camera lens; s3, image capture and transmission: the camera captures a flat cable area image formed by the reflected light, and transmits the image to a processing unit; and S4, defect feature analysis: analyzing the image through a detection algorithm to complete detection. According to the invention, the turnover flat cable can present defect characteristics at a specific angle, and the problems that the mechanism occupied space is large and the type of defects cannot be imaged when a traditional detection scheme is used are solved.

Description

Technical Field

[0001] The present invention relates to the field of visual inspection technology, and in particular to a method for detecting defects in an optical path based on a combination of line-light and line-prism. Background Art

[0002] In existing automated optical inspection equipment, most stations for inspection of folding lines use a standard light source vertical reflection imaging method. This involves placing an area array camera perpendicular to the folding line plane and using strip light reflection to present the characteristics of the folding line plane area. However, this method has the following drawbacks:

[0003] 1. High detection cost: When using an area array camera and a standard light source to detect the turning line, multiple light sources are required for fill light to collect product features, and the mechanism space needs to be large enough to configure the optical system hardware, resulting in high detection hardware costs.

[0004] 2. Large space occupation: Since the area array camera needs to be arranged perpendicular to the plane of the flip line and uses strip light reflection to present the characteristics of the plane area of ​​the line, this layout requires a large amount of space for the mechanism, limiting the flexibility and adaptability of the detection equipment.

[0005] 3. Dynamic range and sensitivity limitations: The dynamic range and sensitivity of standard light sources may not be sufficient to capture all types of defects, especially in highly reflective or low-contrast conditions, which limits the detection system's ability to identify subtle defects.

[0006] Therefore, the existing detection method not only takes up a large amount of space, but also has a large interference from the camera light source, and cannot guarantee compatibility with product defects. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a defect detection method based on a flip-line prism line-light combination optical path, which can allow the flip-line to present defect characteristics at a specific angle, thereby solving the problem that the traditional detection solution takes up a large space and cannot image this type of defect.

[0008] The technical solution adopted by the present invention to solve the technical problem is: a method for detecting defects in an optical path based on a line-light combination of a flip-line prism, comprising the following steps:

[0009] S1. Product positioning and flipping: The flipping device sucks up the mobile phone display flip cable and flips it to the set angle;

[0010] S2. Light source triggering and imaging: The narrow line light source is activated and used in conjunction with the area array camera for fixed-shot imaging. The light source is a narrow line light source, ensuring that the light covers the entire wiring area. The light is diffusely reflected from the surface of the wiring to the triangular prism, which then reflects and adjusts the light path to the camera lens.

[0011] S3, image capture and transmission: The camera captures the image of the wiring area formed by the reflected light and transmits the image to the processing unit;

[0012] S4. Defect feature analysis: Analyze the image through the detection algorithm to complete the detection.

[0013] Furthermore, in step S2 of the present invention, imaging is performed by an imaging system, and the imaging system includes:

[0014] Area array camera: resolution 2448×2048, pixel size 3.45μm; lens magnification 0.3X, working distance 197mm; installation position facing the direction of the prism reflection light path;

[0015] Narrow white line light source: customized based on the length of the flip line; arranged at a 90° spatial angle with the prism;

[0016] Right-angle triangular prism: The reflecting surface has a 45° inclination angle; it is located to the side of the light source and the camera, with the central axis aligned with the cable;

[0017] Flip adsorption mechanism: The adsorption area is limited to the upper middle area of ​​the field of view; it is used to fix the cable and flip it to a predetermined angle.

[0018] Furthermore, the lens of the area array camera of the present invention is arranged adjacent to the narrow white line light source with a spacing of 2 mm; the height of the lens from the product is 40 mm.

[0019] Furthermore, the narrow white line light source of the present invention is tilted, with an inclination angle of 15°.

[0020] Furthermore, the right-angled side height of the right-angled triangular prism of the present invention is 40 mm, and the distance from the light diffusely reflected by the surface of the flip line to the right-angled triangular prism is 157 mm.

[0021] The beneficial effect of the present invention is to solve the defects existing in the background technology.

[0022] 1. Improve detection accuracy: Through imaging technology at a specific angle, the defect characteristics of the flip line can be captured more accurately, thereby improving the accuracy of defect detection.

[0023] 2. Strong environmental adaptability: Since this technology does not rely on standard light sources, it has better adaptability to changes in ambient light and can work under a variety of lighting conditions.

[0024] 3. Improved production efficiency: Manual inspection requires holding the product, flattening the flip cables, and visually inspecting it. This method is time-consuming and relies on the inspector's skill. Adding this technology to automated inspection equipment uses a fixed-frame camera. Due to the customizable light source, the required exposure time is shorter. Combined with the inspection algorithm, this allows for rapid detection of product defects, significantly improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic flow chart of the method of the present invention;

[0026] Figure 2 is a light path diagram of the imaging system of the present invention;

[0027] Figure 3 This is a schematic diagram of the mobile phone display flip cable structure;

[0028] In the figure: 1. Area array camera; 2. Lens; 3. Line light source; 4. Right-angle prism; 5. Product. DETAILED DESCRIPTION

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and preferred embodiments. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0030] like Figure 1-Figure 3 The defect detection method based on the combined optical path of a flip-line prism and line light is shown. Since the parameters of the standard light source, such as the light-emitting element and power, are fixed, the adjustable range of its light intensity distribution and spot size is limited. Its luminous characteristics determine that the spot size and light intensity distribution at a certain distance have a relatively fixed pattern, which is difficult to adjust significantly according to specific needs. Therefore, the product exists in three states under different reflected light: the light spot is too small, the light spot is too large, and the light spot is uniform; among them, a light spot that is too large or too small will result in poor imaging effects. However, this solution uses a narrow line light customized according to the size and characteristics of the product. The line light's lamp beads and diffuser are specially customized, and the spot size is significantly changed on the original basis to adapt to this product. Combined with the use of a prism, the optical path is changed, and the light can be evenly reflected on the wiring area of ​​this product to detect flip-line defects.

[0031] Specific steps are as follows Figure 1 As shown,

[0032] S1. Product positioning and flipping: The flipping device sucks up the mobile phone display flip cable and flips it to the set angle;

[0033] S2. Light source triggering and imaging: The narrow line light source is activated and used in conjunction with the area array camera for fixed-shot imaging. The light source is a narrow line light source, ensuring that the light covers the entire wiring area. The light is diffusely reflected from the surface of the wiring to the triangular prism, which then reflects and adjusts the light path to the camera lens.

[0034] S3. Image capture and transmission: The camera captures the image of the wiring area formed by the reflected light and transmits the image to the processing unit.

[0035] S4. Defect feature analysis: Analyze the image through the detection algorithm to complete the detection.

[0036] The imaging system hardware consists of an area array camera 1, a lens 2, a high-brightness line light source 3, and a right-angle prism 4. During the inspection process, the product 5 moves to the inspection area, and the wiring is sucked up by a mechanical flipping device and flipped to a certain angle to reach the field of view. The light source is turned on and a picture is taken. The customized high-brightness light source is designed based on the product size, which can achieve light coverage of the entire wiring area, allowing a single camera station to complete inspection at a certain angle after the product wiring is flipped.

[0037] The optical configuration of the imaging system is shown in the following table:

[0038]

[0039] The structure of the product turnover line is as follows Figure 3 As shown, in the imaging system of this technology, the product turnover line imaging detection area is the middle area of ​​the upper adsorption in the field of view.

[0040] The optical path of the imaging system is as follows Figure 2 As shown, the non-standard customized narrow surface line light uses the diffuse reflection characteristics of light to illuminate the surface of the product. The surface of the product will reflect light in all directions, so that the contour, texture and other details of the product can be highlighted. When the light reflected by the product reaches the triangular prism, it will be reflected on the surface of the prism. The propagation path of the light can be further adjusted. By setting the angle and position of the prism, the propagation direction of the reflected light can be changed to move toward the direction of the camera lens, which will present the final required imaging effect.

[0041] By combining a customized non-standard brightening light source, a reflective prism, and geometric optical principles, this paper designs a system capable of imaging products under specific conditions. This effectively overcomes the spatial limitations of traditional standard light sources when imaging product defects at specific angles, significantly improving the accuracy and efficiency of product defect detection. The results are:

[0042] 1. Reduce inspection costs: Only one area array camera and one high-brightness line light source are needed, along with a reflective prism and a specific angle to complete the inspection of the flat surface of the product at an inclined angle.

[0043] 2. Reduce debugging difficulty: Only an area array camera and a brightening linear light source are required. The mechanism is compact, occupies little space, the triggering method and working environment are relatively simple, and it is highly stable and easy to maintain.

[0044] 3. Obtain better defect detection effect: Using a customized light source designed according to the product size and structure, the inclined surface is imaged by taking advantage of the characteristics of the light source such as high brightness and uniform illumination, and the imaging effect is obvious.

[0045] The above description only describes specific embodiments of the present invention. Various examples do not limit the essential content of the present invention. After reading the description, ordinary technicians in the relevant technical field can make modifications or variations to the specific embodiments described above without departing from the essence and scope of the invention.

Claims

1. A method for detecting optical path defects based on a combination of line light and a flip line prism, characterized by: The following steps are included: S1. Product positioning and flipping: The flipping device sucks up the mobile phone display flip cable and flips it to the set angle; S2. Light source triggering and imaging: The narrow line light source is activated and used in conjunction with the area array camera for fixed-shot imaging. The light source is a narrow line light source, ensuring that the light covers the entire wiring area. The light is diffusely reflected from the surface of the wiring to the triangular prism, which then reflects and adjusts the light path to the camera lens. S3, image capture and transmission: The camera captures the image of the wiring area formed by the reflected light and transmits the image to the processing unit; S4. Defect feature analysis: Analyze the image through the detection algorithm to complete the detection.

2. The optical path defect detection method based on flip-line prism light combination according to claim 1, characterized in that: In step S2, imaging is performed by an imaging system, and the imaging system includes: Area array camera: resolution 2448×2048, pixel size 3.45μm; lens magnification 0.3X, working distance 197mm; installation position facing the direction of the prism reflection light path; Narrow white line light source: customized based on the length of the flip line; arranged at a 90° spatial angle with the prism; Right-angle triangular prism: The reflecting surface has a 45° inclination angle; it is located to the side of the light source and the camera, with the central axis aligned with the cable; Flip adsorption mechanism: The adsorption area is limited to the upper middle area of ​​the field of view; it is used to fix the cable and flip it to a predetermined angle.

3. The optical path defect detection method based on flip-line prism light combination according to claim 2, characterized in that: The lens of the area array camera is arranged adjacent to the narrow white line light source with a spacing of 2 mm; the height of the lens from the product is 40 mm.

4. The optical path defect detection method based on flip-line prism light combination according to claim 2, characterized in that: The narrow white line light source is tilted at an angle of 15°.

5. The optical path defect detection method based on flip-line prism light combination according to claim 2, characterized in that: The height of the right-angled side of the right-angled triangular prism is 40 mm, and the distance from the light diffusely reflected by the surface of the flip line to the right-angled triangular prism is 157 mm.

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