PCB optical inspection apparatus

Abstract

The application discloses a PCB optical detection device and belongs to the technical field of optical detection. The PCB optical detection device comprises a conveying device for conveying a PCB, a plurality of rollers, a first shooting device arranged below a gap between two adjacent rollers and used for shooting a lower surface area of the PCB between the two adjacent rollers, and at least one set of illumination devices, each set of the illumination devices comprising a reflecting plate and a light source. The reflecting plate is arranged between the two adjacent rollers and on one side of an axis of the first shooting device, a reflecting surface is formed on the reflecting plate, and the reflecting surface is a rough surface. The light source is arranged below the rollers and on the other side of the axis of the first shooting device, the light source is used for emitting light to the reflecting surface, and the reflecting surface is used for diffusely reflecting the light to the PCB. The light incident on the surface of the PCB is low-angle light, which can make the brightness of the shooting position uniform, thereby effectively improving the detection accuracy.

Description

Technical Field

[0001] This application relates to the field of optical inspection technology, and in particular to a PCB optical inspection device. Background Technology

[0002] In the PCB manufacturing industry, to improve the inspection efficiency of PCBs before they leave the factory, the following inspection scheme is used: A conveyor device is set up to transport the PCBs. This device includes several rollers spaced apart. Simultaneously, a camera and a light source are positioned below the conveying plane of the conveyor. The light source illuminates the area of ​​the PCB between two rollers, and the camera captures the illuminated area. While this inspection scheme allows for PCB inspection during transport, the rollers obstruct the light source, causing it to strike the PCB surface at a relatively high angle. When the PCB surface has protrusions, the brightness of the image captured by the camera is uneven, thus affecting the inspection accuracy. Summary of the Invention

[0003] This application aims to solve one of the technical problems existing in the prior art. To this end, this application proposes a PCB optical inspection device in which the light incident on the PCB surface is low-angle light, which can make the brightness of the imaging position uniform, thereby effectively improving the detection accuracy.

[0004] The PCB optical inspection apparatus according to this application includes:

[0005] A conveying device, comprising a plurality of rollers, is used to convey PCBs;

[0006] A first imaging device is disposed below the gap between two adjacent rollers. The first imaging device is used to photograph the lower surface area of ​​the PCB located between the two adjacent rollers.

[0007] At least one set of illumination devices, each set of illumination devices including a reflector and a light source; the reflector is disposed between two adjacent rollers and located on one side of the axis of the first shooting device, and a reflective surface is formed on the reflector, the reflective surface being a rough surface; the light source is disposed below the rollers and located on the other side of the axis of the first shooting device, the light source being used to emit light toward the reflective surface, and the reflective surface being used to diffusely reflect the light onto the PCB.

[0008] The PCB optical inspection apparatus according to the embodiments of this application has at least the following beneficial effects:

[0009] A conveying device consisting of several rollers is installed, and a first imaging device is positioned below the conveying plane to enable PCB inspection during transport, thereby effectively improving the inspection rate. Furthermore, a reflector and a light source are installed between adjacent rollers below the conveying plane. The reflector diffusely reflects the incident light from the light source onto the bottom surface of the PCB, ensuring the light hits the PCB at the lowest possible angle. This prevents excessive incident angles from causing light reflection and interfering with the imaging of the first imaging device, thus improving the inspection accuracy.

[0010] According to some embodiments of this application, the reflector is inclined relative to the conveying plane of the conveying device.

[0011] According to some embodiments of this application, the reflector is made of a highly reflective material.

[0012] According to some embodiments of this application, the reflector is made of a high-strength material.

[0013] According to some embodiments of this application, the irradiation device is provided in two sets.

[0014] According to some embodiments of this application, the two sets of irradiation devices are symmetrically arranged along the axis of the first imaging device.

[0015] According to some embodiments of this application, a direct light source is provided between the two sets of irradiation devices, and the direct light source irradiates the PCB.

[0016] According to some embodiments of this application, the light source is a line light source.

[0017] According to some embodiments of this application, a second imaging device is further provided above the conveying plane of the conveying device, the second imaging device being used to photograph the upper surface of the PCB.

[0018] According to some embodiments of this application, the first imaging device and the second imaging device are line scan cameras.

[0019] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0020] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0021] Figure 1 This is a perspective view of a PCB optical inspection device in one embodiment of this application.

[0022] Figure 2 This is a side view of a PCB optical inspection device in one embodiment of this application.

[0023] Figure 3 This is a schematic diagram showing what happens when a PCB is illuminated by high-angle light.

[0024] Figure 4 This is a schematic diagram illustrating what happens when a PCB is illuminated by low-angle light.

[0025] Figure 5 This is a schematic diagram illustrating what happens when a PCB is illuminated by mixed light from high and low angles.

[0026] Figure 6 This is a side view of a PCB optical inspection device in another embodiment of this application. Detailed Implementation

[0027] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0028] In the description of this application, it should be understood that the orientation descriptions, such as up, down, left, right, front, and back, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0029] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0030] The following is based on Figures 1 to 6 This application describes the PCB optical inspection device.

[0031] refer to Figures 1 to 5 The PCB optical inspection device of this application includes:

[0032] A conveying device, including several rollers 100, is used to convey PCB 200;

[0033] The first shooting device 510 is disposed below the gap between two adjacent rollers 100. The first shooting device 510 is used to shoot the lower surface area of ​​the PCB 200 located between the two adjacent rollers 100.

[0034] At least one set of illumination devices, each set of illumination devices including a reflector 300 and a light source 400; the reflector 300 is disposed between two adjacent rollers 100 and located on one side of the axis of the first shooting device 510, and a reflective surface is formed on the reflector 300, the reflective surface being a rough surface; the light source 400 is disposed below the rollers 100 and located on the other side of the axis of the first shooting device 510, the light source 400 is used to emit light toward the reflective surface, and the reflective surface is used to diffusely reflect the light to the PCB 200.

[0035] Understandably, the conveyor can be placed between two adjacent workstations to enable the connection between two adjacent processing steps of PCB 200.

[0036] The conveying device consists of several rollers 100, with gaps between each roller 100. With this configuration, by placing a first imaging device 510 below the gap between two adjacent rollers 100, the lower surface of the PCB 200 can be imaged and inspected. This allows for image inspection of both the upper and lower surfaces of the PCB 200 during the conveying process, which improves the inspection speed. Furthermore, this configuration eliminates the need for a separate inspection station for the PCB 200, enabling simultaneous inspection of both the upper and lower surfaces. Therefore, the PCB 200 inspection device has a simple structure and low cost.

[0037] Furthermore, since the detection area on the lower surface of the PCB 200 is located between two adjacent rollers 100, the brightness of this detection area is relatively low. Consequently, the first imaging device 510 cannot accurately acquire an image of the detection area, resulting in a high detection error rate. Therefore, to improve the brightness of the PCB 200 detection area, an illumination device is installed below the conveying plane of the conveying device to illuminate the area of ​​the PCB 200 located between two adjacent rollers 100.

[0038] Specifically, the illumination device includes a reflector 300 disposed on one side of the axis of the first imaging device 510 and a light source 400 disposed on the other side of the axis of the first imaging device 510. It should be understood that the reflective surface on the reflector 300 is a rough surface, which allows the incident light to undergo diffuse reflection on the reflective surface, thereby reflecting onto the PCB board 200 at both high and low angles, making the brightness of the detection area on the PCB board 200 uniform.

[0039] Specifically, refer to Figures 3-5 , Figures 3-5 These are all schematic diagrams of the optical path under non-diffuse reflection conditions. Figure 3 This is a schematic diagram of the light path after reflection on PCB 200 under high-angle illumination. Figure 3It is known that at the protrusion of PCB 200, after two sets of parallel light are irradiated on the protrusion of PCB 200, only one set of light is reflected along the direction parallel to the axis of the imaging device, while the other set of light is reflected at a certain angle to the axis of the first imaging device 510. If both sets of reflected light are incident into the first imaging device 510, since the two sets of reflected light are not parallel to each other, the brightness of the two sets of reflected light will be inconsistent, which will lead to uneven brightness of the imaging image in the first imaging device 510 and affect the detection accuracy. Figure 4 This is a schematic diagram of the light path after reflection on PCB 200 under low-angle illumination. Figure 4 It is known that low-angle light can cause the light to strike the raised edge on the PCB 200 and then enter the imaging device in a direction parallel to the axis of the first imaging device 510. Therefore, in order to make the brightness of the raised area on the PCB 200 uniform, multiple sets of light at different angles are generally set at the same time. However, due to the structural limitations of the roller 100, low-angle light that is too low will be blocked by the roller 100 and thus cannot strike the PCB 200.

[0040] Therefore, to ensure that the light source 400 can simultaneously illuminate the PCB 200 at both high and low angles, a reflector 300 is positioned between two adjacent rollers 100, and the reflective surface of the reflector 300 is rough. Light emitted from the light source 400 is diffusely reflected by the reflector 300 onto the detection area of ​​the PCB 200 after hitting the reflector 300. (Reference) Figure 5 Through diffuse reflection, the light source 400 can simultaneously illuminate the detection area on the PCB 200 at both low and high angles. That is, the light reflected from the reflective surface can illuminate the protrusions on the PCB 200 at multiple angles, allowing multiple sets of reflected light to enter the first imaging device 510 in a direction parallel or nearly parallel to its axis. This effectively prevents high-angle light from hitting the PCB 200 and causing specular reflection that could interfere with the lens, and also ensures that the edges of the protrusions on the PCB 200 are uniformly illuminated. Furthermore, the edge of the reflector 300 is positioned as close as possible to the conveying plane of the conveying device. This arrangement allows the reflector 300 to provide light at the lowest possible angle, enabling the first imaging device 510 to more clearly and accurately capture the detection area of ​​the PCB 200.

[0041] By setting the above, this application makes the brightness of the detection area on PCB 200 more uniform, which can avoid local high brightness from interfering with the first imaging device 510, or local insufficient brightness from causing inaccurate quality assessment, thus improving detection accuracy and detection correctness.

[0042] refer to Figure 1 and Figure 2In some embodiments of this application, the reflector 300 is inclined relative to the conveying plane of the conveying device.

[0043] Understandably, this arrangement of the reflector 300 allows more light from the same light source 400 to illuminate it. Furthermore, the angle between the reflector 3000 and the transport plane is acute, and even further, the acute angle can be less than 45°. This arrangement improves the utilization rate of the light source 400 and further enhances the brightness of the detection area on the PCB 200, thus improving detection accuracy.

[0044] refer to Figure 3 In some embodiments of this application, the reflector 300 is made of a highly reflective material. For example, a metallic material, preferably a high-strength alloy metal such as stainless steel. This arrangement increases the reflectivity of light, ensuring that the brightness of the PCB 200 inspection area meets inspection requirements even when using a lower-power light source 400, thereby reducing the manufacturing cost of the PCB optical inspection device.

[0045] refer to Figure 3 and Figure 4 In some embodiments of this application, two sets of irradiation devices are provided. Specifically, the two sets of irradiation devices can be arranged symmetrically along the axis of the first imaging device 510, or they can be arranged asymmetrically.

[0046] When the two sets of illumination devices are symmetrically arranged, the reflectors 300 in the two sets of illumination devices are respectively placed close to the two adjacent rollers 100. The light source 400 in each set of illumination devices illuminates the reflector 300 in each set of illumination devices, thereby reducing the brightness difference between the two sides of the protrusion on the PCB 200 detection area and avoiding the situation where one side of the protrusion is bright while the other side is too dark. This makes the brightness of the two sides of the protrusion on the PCB 200 detection area uniform, which is beneficial to improving the detection accuracy of the imaging device.

[0047] When the two sets of illumination devices are asymmetrically arranged, the reflectors 300 in the two sets of illumination devices can be symmetrically arranged, but the light sources 400 in the two sets of illumination devices can be asymmetrically arranged. That is, the incident angles of the light sources 400 in the two sets of illumination devices are different. Thus, by adjusting the brightness difference of the light sources 400 in the two sets of illumination devices, the ratio of high-angle light and low-angle light incident on the reflectors 300 can be achieved, thereby achieving different brightness illumination requirements.

[0048] refer to Figure 6 In some embodiments of this application, a direct light source 600 is provided between two sets of irradiation devices, and the direct light source 600 irradiates the PCB.

[0049] Understandably, the direct light source 600 is configured with two sets of illumination devices, resulting in a relatively large angle between the direct light source 600 and the PCB board. Specifically, the angle between the direct light source 600 and the PCB board can be greater than 45°, and in some cases, it can even be 90°. This configuration allows the reflector 300 to provide low-angle light to the PCB 200 while the direct light source 600 provides high-angle light. The high-angle and low-angle light work together, making it applicable to a wider range of PCB 200 models and thus broadening its applicability.

[0050] refer to Figure 5 In some embodiments of this application, a second shooting device 520 is also provided above the conveying plane of the conveying device, and the second shooting device 520 is used to shoot the upper surface of the PCB 200.

[0051] It is understandable that a second imaging device 520 is set above the conveying plane of the conveying device. When the PCB 200 is driven by the conveying device to move on the conveying plane, the second imaging device 520 can capture images of the PCB 200 passing below it, thereby realizing the imaging and detection of the upper surface of the PCB 200 during the conveying process of the PCB 200.

[0052] refer to Figure 5 In some embodiments of this application, the light source 400 is a line light source 400, and the first imaging device 510 and the second imaging device 520 are line scan cameras.

[0053] Specifically, the light source 400 is a line light source 400, which is relatively long and has uniform brightness, making it suitable for the wide PCB 200. Furthermore, the light source 400 can be a focusable light source 400, allowing the focal point of the beam to be located on the reflective surface of the reflector 300. This enables the reflector 300 to diffuse more light onto the detection area on the PCB 200, improving the utilization rate of the light source 400 and thus increasing optical efficiency. Meanwhile, the second imaging device 520 is a line scan camera. It is understood that the first imaging device 510 can also be a line scan camera.

[0054] Specifically, the operation process of the PCB optical inspection device in this application is as follows:

[0055] The conveyor continuously moves the PCB 200 forward. During this process, two sets of light sources 400 are activated simultaneously and illuminate the reflector 300. The reflector 300 diffusely reflects the light from the light sources 400 onto the detection area on the PCB 200. The light is reflected again on the PCB 200 and enters the first imaging device 510 to form an image. At the same time, the second imaging device 520 also takes an image of the upper surface of the PCB 200.

[0056] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

Claims

1. A PCB optical inspection device, characterized in that, include: A conveying device, comprising a plurality of rollers, is used to convey PCBs; A first imaging device is disposed below the gap between two adjacent rollers. The first imaging device is used to photograph the lower surface area of ​​the PCB located between the two adjacent rollers. At least one set of illumination devices, each set of illumination devices including a reflector and a light source; the reflector is disposed between two adjacent rollers and located on one side of the axis of the first shooting device, and a reflective surface is formed on the reflector, the reflective surface being a rough surface; the light source is disposed below the rollers and located on the other side of the axis of the first shooting device, the light source being used to emit light toward the reflective surface, and the reflective surface being used to diffusely reflect the light onto the PCB.

2. The PCB optical inspection device according to claim 1, characterized in that: The reflector is inclined relative to the conveying plane of the conveying device.

3. The PCB optical inspection device according to claim 1, characterized in that: The reflector is made of a highly reflective material.

4. The PCB optical inspection device according to claim 1, characterized in that: The reflector is made of high-strength material.

5. The PCB optical inspection device according to claim 1, characterized in that: The irradiation device is provided in two sets.

6. The PCB optical inspection device according to claim 5, characterized in that: The two sets of irradiation devices are symmetrically arranged along the axis of the first imaging device.

7. The PCB optical inspection device according to claim 5, characterized in that: A direct light source is provided between the two sets of irradiation devices, and the direct light source irradiates the PCB.

8. The PCB optical inspection device according to claim 1, characterized in that: The light source is a line light source.

9. The PCB optical inspection device according to claim 1, characterized in that: A second imaging device is also provided above the conveying plane of the conveying device, which is used to photograph the upper surface of the PCB.

10. The PCB optical inspection device according to claim 9, characterized in that: The first and second shooting devices are line scan cameras.

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