An optical imaging system for circuit board inspection

Abstract

This utility model relates to the field of circuit board appearance defect detection technology, specifically to an optical imaging system for circuit board inspection, including a multi-angle illumination device that can provide angular illumination from 0° to 180° in increments of 25-35°; and a light homogenizing device that is disposed in the optical path of the multi-angle illumination device, which solves the problem of repeated defect imaging and increased difficulty in algorithm deduplication.

Description

Technical Field

[0001] This utility model relates to the field of circuit board appearance defect detection technology, and more specifically, to an optical imaging system for circuit board inspection. Background Technology

[0002] To meet the defect detection requirements of metal pad areas and ink areas, many defects have a certain viewing angle. When observing with the human eye, the product is usually rotated to observe from multiple angles. In actual production, it is not possible to set up cameras at multiple angles to take pictures, as this would result in repeated shooting of defects, increasing the difficulty of deduplication algorithms and increasing hardware costs. Utility Model Content

[0003] This invention provides an optical imaging system for circuit board inspection, which solves the problem of "repeated defect imaging, increasing the difficulty of algorithm deduplication".

[0004] It includes:

[0005] A multi-angle lighting device capable of providing angular lighting from 0° to 180° in increments of 25-35°.

[0006] It is positioned in the optical path of the multi-angle lighting device.

[0007] By designing a multi-angle lighting device, it is possible to ensure comprehensive and thorough inspection of circuit board defects, avoiding missed detections caused by single-angle lighting. The installation of a light-diffusing device ensures the consistency and uniformity of light, improving inspection accuracy.

[0008] Preferably, the light output by the multi-angle illumination device is at least coaxial light in one image capturing direction, and one or more image capturing devices are arranged around it.

[0009] The coaxial light design reduces shadow interference from the image capturing device's shooting direction. Simultaneously, multiple image capturing devices can acquire image information from different angles, further improving the comprehensiveness and accuracy of the detection.

[0010] The preferred angle is 30°, which is 25-35°. Choosing 30° as the illumination angle interval can maximize the utilization efficiency of the light source 3 while ensuring the illumination coverage, making the detection results more stable and reliable, and reducing inconsistencies caused by angle changes.

[0011] Preferably, the multi-angle lighting device includes at least two separately arranged light source 3 systems, each comprising a light source 3 and a heat sink 2.

[0012] The separately arranged light source 3 system helps to disperse heat, prevent overheating from affecting the performance of the light source 3, thereby extending the service life of the equipment and maintaining stability during long-term operation.

[0013] Preferably, each light source 3 system includes two sets of light sources 3, whose light source 3 axes are at 30° to each other.

[0014] The 30° angled design of the three axes of the light source optimizes the light distribution, making the illumination more balanced in all directions, enhancing the ability to identify defects of different shapes, and improving the detection quality.

[0015] Preferably, the multi-angle lighting device includes two sets of symmetrically arranged light source 3 systems, providing light paths of 30°, 60°, 120°, and 150°, which converge in the area to be detected.

[0016] The symmetrically arranged light source 3 system and the optical path design at specific angles (30°, 60°, 120°, 150°) ensure effective coverage of the light in the area to be inspected, achieving all-round and efficient inspection. It is especially suitable for the inspection of circuit boards with complex structures, ensuring multi-angle and symmetrical illumination, and avoiding the weakening of defect presentation ability due to insufficient illumination angle. If the angle is further increased, the light source 3 will tend to have high uniformity, and the contrast of defects will decrease. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a structural diagram of an embodiment of the present utility model.

[0019] 1-Camera, 2-Heat sink, 3-Light source, 4-Light diffuser. Detailed Implementation

[0020] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0021] To address the problems mentioned in the prior art, this invention provides an optical imaging system for circuit board inspection, such as... Figure 1 It includes:

[0022] Multi-angle illumination device: The multi-angle illumination device can provide angular illumination from 0° to 180° in increments of 25-35°. In specific implementations, the device consists of multiple independent light source modules, which are precisely installed in predetermined positions to ensure coverage of the required angle range. For example, in a typical configuration, six light source modules may be set up, corresponding to angles of 0°, 30°, 60°, 90°, 120°, and 150° respectively, thereby achieving omnidirectional illumination of surface defects on the circuit board. Each light source module integrates high-brightness LED beads, and the brightness of each module is adjusted by a control system to adapt to different detection requirements.

[0023] Light homogenizing device: It is installed in the optical path of the multi-angle lighting device. The light homogenizing device adopts a high-transmittance light homogenizing plate 4. This material can not only homogenize light from different directions, but also reduce the graininess of the light source 3, making the light illuminating the circuit board surface softer and smoother. In addition, to further optimize the light distribution, a diffuser film can be added in front of the light homogenizing plate 4, which helps to further improve the consistency and uniformity of the illumination.

[0024] The multi-angle illumination device outputs coaxial light in at least one image-grabbing direction, and one or more image-grabbing devices are arranged around it. Specifically, in practical applications, a vertically downward-illuminating coaxial light source 3 can be placed at the center of the device, working in conjunction with a high-definition camera to acquire frontal images. Simultaneously, several side-view cameras 1 (image-grabbing devices) are arranged around this coaxial light source 3. These cameras 1 can capture information from the sides of the circuit board from different angles, forming a multi-view image dataset. This method effectively avoids the shadow occlusion problem that may occur under a single viewpoint, ensuring the comprehensiveness and accuracy of defect detection.

[0025] The multi-angle lighting device comprises at least two separately arranged light source systems, each containing a light source 3 and a heat sink 2. To prevent the light source 3 from overheating and affecting performance during prolonged operation, each light source 3 system is equipped with a high-efficiency heat sink 2. These heat sinks 2 are typically made of aluminum alloy, which has good thermal conductivity. In practical designs, active cooling measures such as fans can be combined to further improve heat dissipation. The separately arranged light source 3 systems not only help to distribute heat but also allow for flexible adjustment of the operating status of each light source 3 module as needed to meet the requirements of different detection tasks.

[0026] In this embodiment, each light source 3 system includes two sets of light sources 3, with their axes at 30° to each other. This layout optimizes light distribution, resulting in more balanced illumination in all directions. For example, in a set of light source 3 systems, the two light sources 3 can be mounted on opposite sides of the base, with their optical axes intersecting at a single point, forming a stable triangular light field. This design not only enhances the ability to identify defects of different shapes but also improves the overall inspection quality. Furthermore, to ensure accurate positioning of the light sources 3, precision mechanical components are typically used to fix the position and angle of the light sources 3.

[0027] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0028] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An optical imaging system for circuit board inspection, characterized in that, include: A multi-angle lighting device capable of providing angular lighting from 0° to 180° in increments of 25-35°. A light-diffusing device is disposed in the optical path of the multi-angle lighting device.

2. The optical imaging system for circuit board inspection according to claim 1, characterized in that, The light output by the multi-angle illumination device is at least coaxial light in one image capturing direction, and one or more image capturing devices are arranged around it.

3. The optical imaging system for circuit board inspection according to claim 1, characterized in that, The 25-35° is preferably 30°.

4. The optical imaging system for circuit board inspection according to claim 1, characterized in that, The multi-angle lighting device includes at least two separately arranged light source systems 3, each comprising a light source 3 and a heat sink 2.

5. The optical imaging system for circuit board inspection according to claim 4, characterized in that, Each light source 3 system contains two sets of light sources 3, whose light source 3 axes are at 30° to each other.

6. The optical imaging system for circuit board inspection according to claim 5, characterized in that, The multi-angle lighting device includes two sets of symmetrically arranged light source 3 systems, providing light paths of 30°, 60°, 120° and 150°, which converge in the area to be detected.

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