Printed circuit board hole inspection machine and inspection method

Abstract

The present invention provides a printed circuit board hole inspection machine and inspection method, relating to the technical field of printed circuit board manufacturing. The printed circuit board hole inspection machine includes an optical hole inspection component and a controller, wherein the optical hole inspection component includes a variable light illumination unit and an image acquisition unit. The variable light illumination unit is used to generate detection light of different colors. The image acquisition unit is used to collect detection light passing through a small hole provided on the printed circuit board to be inspected. The controller is used to select an illumination color that matches the thickness-to-diameter ratio of the small hole and control the variable light illumination unit to emit light of the corresponding color according to the selected illumination color. The inspection method includes: obtaining the thickness-to-diameter ratio of the small hole on the printed circuit board; selecting the color of the detection light according to the thickness-to-diameter ratio; and controlling the variable light illumination unit to emit light of the corresponding color according to the selected detection light color. The solution provided by the present invention can improve the inspection accuracy of small holes with a high thickness-to-diameter ratio.

Description

Technical Field

[0001] The invention relates to a printed circuit board hole inspection machine and a detection method, belonging to the technical field of printed circuit board manufacturing. Background Art

[0002] Printed circuit boards (PCBs), also known as printed circuit boards, provide electrical connections for electronic components. The development of PCBs toward higher density, higher precision, higher aspect ratios, thinner conductors, smaller pitches, higher reliability, multilayering, and higher-speed signal transmission has increased challenges in PCB fabrication, particularly in quality inspection. For example, during PCB fabrication, small holes must be inspected to determine whether they are blocked or whether their diameters match the designed values.

[0003] Currently, optical inspection is commonly used to inspect small holes on PCBs. Existing printed circuit board hole inspection machines for inspecting small holes on PCBs include a conveyor unit for conveying the PCBs, and lighting units and image acquisition units located on either side of the conveyor unit. The lighting unit emits inspection light toward the image acquisition unit, which then passes through the small holes on the PCB and is captured by the image acquisition unit on the opposite side. Based on information such as the intensity of the light signal captured by the image acquisition unit, the aperture size of the small hole on the PCB and whether it is blocked can be calculated.

[0004] However, the inspection accuracy of the printed circuit board hole inspection machine in the prior art for small holes with a high aspect ratio is very poor, and may even fail to detect. Summary of the Invention

[0005] The present invention provides a printed circuit board hole inspection machine and a detection method, so as to solve the problem that the printed circuit board hole inspection machine in the prior art has poor inspection accuracy for small holes with a high aspect ratio.

[0006] A first aspect of the present invention is to provide a printed circuit board hole inspection machine, comprising an optical hole inspection component and a controller, wherein the optical hole inspection component comprises a variable light illumination unit and an image acquisition unit;

[0007] The light-changing lighting unit is used to generate detection lights of different colors;

[0008] The image acquisition unit is used to collect the detection light passing through the small hole set on the printed circuit board to be inspected;

[0009] The controller is used to select a lighting color that matches the aspect ratio of the aperture according to the aspect ratio of the aperture and control the light-changing lighting unit to emit light of a corresponding color according to the selected lighting color.

[0010] Optionally, the light-changing lighting unit includes an LED color-changing lamp and a light-uniform cover, and the LED color-changing lamp is communicatively connected to the controller.

[0011] Optionally, the variable light illumination unit includes a single color light source and a color wheel, and the color wheel is rotatable around a rotation axis. A plurality of fluorescent coatings of different colors are provided on the color wheel, and the plurality of fluorescent coatings of different colors are arranged around the rotation axis.

[0012] Optionally, the variable light lighting unit further includes an outer shell and a motor for driving the color wheel to rotate, the single color light source and the color wheel are both located in the outer shell, and a light hole is provided on the outer shell for the detection light to pass through; the motor is communicatively connected to the controller.

[0013] Optionally, further comprising a light intensity sensor communicatively connected to the controller;

[0014] Optionally, the controller is further configured to control the variable light illumination unit to emit reference light;

[0015] Optionally, the light intensity sensor is used to detect the illumination intensity of the reference light passing through a small hole on the printed circuit board to be inspected.

[0016] Optionally, the image acquisition unit includes a contact image processor and an image acquisition card, and the image acquisition card is communicatively connected to the contact image processor and the controller respectively.

[0017] Optionally, a plurality of groups of the optical hole detection components are arranged at intervals along the traveling direction of the printed circuit board to be inspected.

[0018] Optionally, the light-modulating illumination units of two adjacent groups of the optical hole detection assemblies are respectively arranged on both sides of the printed circuit board to be detected, and the optical paths of the detection lights emitted by the two light-modulating illumination units are parallel to each other and have no overlap.

[0019] The present invention provides a printed circuit board hole inspection machine, comprising an optical hole inspection component and a controller, wherein the optical hole inspection component comprises a variable light illumination unit and an image acquisition unit; the variable light illumination unit is used to generate detection light of different colors; the image acquisition unit is used to collect the detection light passing through a small hole set on the printed circuit board to be inspected; the controller is used to select an illumination color that is compatible with the thickness-to-diameter ratio of the small hole and control the variable light illumination unit to emit light of a corresponding color according to the selected illumination color. The printed circuit board hole inspection machine provided by the present invention has a controller that selects a lighting color that is compatible with the aspect ratio of the small hole on the printed circuit board to be inspected, and controls the variable light illumination unit to emit detection light of the corresponding color according to the selected lighting color. Since light of different colors has different wavelengths, it can effectively adapt to small holes with different aspect ratios, so that the detection light can effectively pass through the small holes and be collected by the image acquisition unit, thereby effectively avoiding the influence of small holes with high aspect ratios on the detection light, ensuring the intensity of light passing through the small holes with high aspect ratios, thereby improving the inspection accuracy of small holes with high aspect ratios and avoiding the situation where small holes with high aspect ratios cannot be detected.

[0020] A second aspect of the present invention is to provide a method for detecting small holes on a printed circuit board, comprising:

[0021] Obtaining the aspect ratio of the small hole on the printed circuit board;

[0022] selecting a color of the detection light according to the aspect ratio;

[0023] The light-variable lighting unit is controlled to emit light of a corresponding color according to the selected detection light color.

[0024] Optionally, obtaining the aspect ratio of the small hole on the printed circuit board specifically includes:

[0025] The illumination intensity of the reference light is obtained, and the aspect ratio of the small hole is obtained by searching in a database according to the illumination intensity of the reference light.

[0026] The present invention provides a method for detecting small holes on a printed circuit board, comprising: obtaining the aspect ratio of the small holes on the printed circuit board; selecting a color of detection light based on the aspect ratio; and controlling a variable light illumination unit to emit light of a color corresponding to the selected detection light color. The present invention determines the color of the detection light based on the aspect ratio of the small holes on the printed circuit board to be tested, and controls the variable light illumination unit to emit detection light of the same color. Small holes with different aspect ratios are matched to different colors of detection light, ensuring the detection accuracy of small holes with high aspect ratios. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other objects, features and advantages of the embodiments of the present invention will become more readily understood through the following detailed description with reference to the accompanying drawings, in which several embodiments of the present invention are illustrated by way of example and not limitation, in which:

[0028] Figure 1 A schematic diagram of inspecting a printed circuit board using the printed circuit board hole inspection machine provided by the present invention;

[0029] Figure 2 A schematic structural diagram of a first light-variable lighting unit of a printed circuit board hole inspection machine provided by the present invention;

[0030] Figure 3 A schematic structural diagram of a second light-variable lighting unit of a printed circuit board hole inspection machine provided by the present invention;

[0031] Figure 4 A schematic diagram of a first color wheel structure of a printed circuit board hole inspection machine provided by the present invention;

[0032] Figure 5 A schematic diagram of a second color wheel structure of a printed circuit board hole inspection machine provided by the present invention;

[0033] Figure 6 The present invention provides a structural diagram of a printed circuit board hole inspection machine.

[0034] Description of reference numerals:

[0035] 100- Optical hole inspection component;

[0036] 11- variable light lighting unit;

[0037] 111-LED color changing light;

[0038] 112-light uniformity mask;

[0039] 113-single color light source;

[0040] 114-color wheel;

[0041] 115-fluorescent coating;

[0042] 116- outer shell;

[0043] 1161-light hole;

[0044] 12- Image acquisition unit;

[0045] 121-contact image processor;

[0046] 122-image acquisition card;

[0047] 200-Controller. DETAILED DESCRIPTION

[0048] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, but are not to be construed as limiting the present invention.

[0049] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" or "multiple groups" means at least two, such as two or three, unless otherwise specifically defined. Furthermore, the term "small hole" in the description of the present invention refers to the printed circuit board and is used for ease of description only.

[0050] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0051] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0052] Printed circuit boards (PCBs), also known as printed circuit boards, provide electrical connections for electronic components. The development of PCBs toward higher density, higher precision, higher aspect ratios, thinner conductors, smaller pitches, higher reliability, multilayering, and higher-speed signal transmission has increased challenges in PCB fabrication, particularly in quality inspection. For example, during PCB fabrication, small holes must be inspected to determine whether they are blocked or whether their diameters match the designed values.

[0053] Currently, optical inspection is commonly used to inspect small holes on PCBs. Existing printed circuit board hole inspection machines for inspecting small holes on PCBs include a conveying unit for conveying the PCBs, and lighting units and image acquisition units located on either side of the conveying unit. The lighting unit emits inspection light toward the image acquisition unit, which then passes through the small holes on the PCB and is captured by the image acquisition unit on the opposite side. Based on information such as the intensity of the light signal captured by the image acquisition unit, the aperture size of the small hole on the PCB and whether it is blocked can be calculated.

[0054] However, for printed circuit boards (PCBs) with small holes with a high aspect ratio (the aspect ratio is the ratio of the thickness of the PCB board to the diameter of the small holes set on the PCB board), the hole wall colors vary due to the different materials or different color surface treatment processes of the PCB boards. When the single-color detection light of existing PCB hole inspection machines passes through small holes with different aspect ratios, the illumination intensity of the single-color detection light passing through the small holes also varies. Furthermore, when the illumination intensity of the single-color detection light passing through the small holes with a high aspect ratio becomes weaker, it is necessary to increase the illumination intensity of the single-color detection light. However, this will cause tiny metal burrs or glass fibers in the small holes with a high aspect ratio to be seen through by the overly bright single-color detection light, resulting in the inability to detect the small holes with a high aspect ratio. Therefore, the inspection accuracy of the PCB hole inspection machines in the prior art for small holes with a high aspect ratio is very poor, and may even make detection impossible.

[0055] Taking into account that light sources of different colors have different wavelengths and thus have different abilities to penetrate a small hole, the inventors abandoned the solution of using a single color of detection light to detect the small hole. Instead, they used a variable light illumination unit to provide detection light of multiple different colors and determined the corresponding illumination color according to the aspect ratio of the small hole. The variable light illumination unit is then controlled to emit detection light of the corresponding color according to the corresponding illumination color. This ensures that the illumination intensity of the detection light passing through the small hole with a high aspect ratio is within a predetermined range, avoids excessive differences between the collected image and the actual image, and improves the inspection accuracy of small holes with a high aspect ratio.

[0056] The printed circuit board hole inspection machine provided by the invention is described in detail below with reference to specific embodiments.

[0057] Figure 1 A schematic diagram of inspecting a printed circuit board using the printed circuit board hole inspection machine provided by the present invention;

[0058] Figure 2 A schematic structural diagram of a first light-variable lighting unit of a printed circuit board hole inspection machine provided by the present invention; Figure 3 A schematic structural diagram of a second light-variable lighting unit of a printed circuit board hole inspection machine provided by the present invention; Figure 4 A schematic diagram of a first color wheel structure of a printed circuit board hole inspection machine provided by the present invention; Figure 5 A schematic diagram of a second color wheel structure of a printed circuit board hole inspection machine provided by the present invention;

[0059] Figure 6 The present invention provides a structural diagram of a printed circuit board hole inspection machine.

[0060] like Figure 1 As shown, the printed circuit board hole inspection machine provided by the present invention includes an optical hole inspection component 100 and a controller 200. The optical hole inspection component 100 includes a variable light illumination unit 11 and an image acquisition unit 12. The variable light illumination unit 11 is used to generate detection light of different colors. The image acquisition unit 12 is used to collect the detection light passing through the small hole set on the printed circuit board to be inspected. The controller 200 is used to select an illumination color that is compatible with the aspect ratio of the small hole and control the variable light illumination unit 11 to emit light of the corresponding color according to the selected illumination color.

[0061] The variable light illumination unit 11 and the image acquisition unit 12 are respectively arranged on either side of the printed circuit board to be inspected, so that the inspection light emitted by the variable light illumination unit 11 passes through the printed circuit board to be inspected, ensuring that the inspection light can enter the small hole set on the printed circuit board to be inspected. During use, the printed circuit board to be inspected enters between the variable light illumination unit 11 and the image acquisition unit 12 along the conveying unit. Then, the controller 200 determines the color of the inspection light that the variable light illumination unit 11 should emit based on the aspect ratio of the small hole on the printed circuit board to be inspected. Then, the controller 200 controls the variable light illumination unit 11 to emit light corresponding to the illumination color, so that the color of the inspection light matches the color of the hole wall of the hole, avoiding a significant weakening of the illumination intensity of the inspection light after passing through the hole, thereby achieving inspection of small holes with high aspect ratios.

[0062] In an optional embodiment, as Figure 2 As shown, the light-changing lighting unit 11 includes an LED color-changing light 111 and a light-homogenizing cover 112, and the LED color-changing light 111 is in communication with the controller 200. By cooperating with the LED color-changing light 111 and the light-homogenizing cover 112, the light-changing lighting unit 11 can emit different colors of detection light to adapt to small holes with different aspect ratios, thereby improving detection accuracy.

[0063] To enable the variable illumination unit 11 to generate a variety of different colors of detection light, a color-changing LED lamp 111 can be used. The color-changing LED lamp 111 can be composed of multiple LEDs of different colors. By controlling the current, the intensity of the detection light can be varied, making the captured image closer to the actual image and improving inspection accuracy. The shape of the LEDs can be a rectangular parallelepiped, a sphere, a hemisphere, or other structures, but this invention does not specify this.

[0064] Because the color-changing LED lamp 111 is composed of a plurality of different colored lamp beads, each of which is positioned differently relative to the printed circuit board to be inspected, a uniform light shield 112 can be used to disperse the light emitted by the color-changing LED lamp 111 so that the inspection light emitted by the variable light illumination unit 11 passes simultaneously through the high-aspect-ratio aperture located within the inspection area, thereby meeting the inspection requirements. The uniform light shield 112 can be a hemispherical structure, a rectangular trough structure, or a U-shaped flat plate structure, and the present invention does not provide a specific configuration here.

[0065] In an optional embodiment, as Figure 3 As shown, the variable light illumination unit 11 includes a single-color light source 113 and a color wheel 114. The color wheel 114 is rotatable about a rotation axis. Multiple fluorescent coatings 115 of different colors are disposed on the color wheel 114, and the multiple fluorescent coatings 115 of different colors are arranged around the rotation axis. By combining the single-color light source 113 with the fluorescent coatings 115 of different colors at different positions on the color wheel 114, the variable light illumination unit 11 can emit detection light of different colors to accommodate apertures with different aspect ratios, thereby improving detection accuracy.

[0066] The color wheel 114 can be a rectangular flat plate, a circular flat plate, or a circular ring structure, though this invention does not specify a specific configuration. During operation, the color wheel 114 rotates about its axis, allowing the single-color light source 113 to interact with the fluorescent coating 115 at different locations on the color wheel 114. Consequently, the variable-light illumination unit 11 can emit detection light of a color corresponding to the aspect ratio, thereby meeting the inspection requirements of the printed circuit board hole inspection machine.

[0067] like Figure 4 and Figure 5 As shown, the number of fluorescent coatings 115 can be determined based on the inspection requirements of the printed circuit board hole inspection machine. For example, the number of fluorescent coatings 115 can be 2, 3, 4, or 5. Furthermore, the shape of the fluorescent coatings 115 can be fan-shaped, semicircular, or rectangular, etc., which is not specifically defined in the present invention. A gap can be provided between adjacent fluorescent coatings 115, or no gap can be provided between adjacent fluorescent coatings 115.

[0068] The position of the single-color light source 113 relative to the color wheel 114 can remain unchanged, or the position of the single-color light source 113 relative to the color wheel 114 can be variable. When the position of the single-color light source 113 relative to the color wheel 114 is variable, the number of fluorescent coatings 115 provided on the color wheel 114 can be increased, thereby increasing the variety of detection light colors generated by the variable light illumination unit 11.

[0069] Alternatively, as Figure 3 As shown, the variable light lighting unit 11 also includes an outer shell 116 and a motor for driving the color wheel 114 to rotate. The single color light source 113 and the color wheel 114 are both located in the outer shell 116, and a light hole 1161 is provided on the outer shell 116 for the detection light to pass through; the motor is communicatively connected to the controller 200.

[0070] The color wheel 114 and the single-color light source 113 are disposed within the outer housing 116, thereby reducing the overall size of the variable-lighting unit 11 and ensuring the proper positioning and coordination of the color wheel 114 and the single-color light source 113, thereby ensuring that the light emitted by the variable-lighting unit 111 is the detection light of the predetermined color. During operation, the single-color light source 113 remains positioned relative to the color wheel 114. The controller 200 controls the motor to rotate the color wheel 114, thereby aligning the fluorescent coating 115 at different locations on the color wheel 114 with the single-color light source 113.

[0071] The light hole 1161 not only allows the detection light to illuminate the printed circuit board to be inspected, but also controls the illumination range of the detection light to ensure the inspection effect. The light hole 1161 can be a regular hole such as a circular hole, a triangular hole, or a rectangular hole, or an irregular hole, which is not specifically set in this invention.

[0072] Optionally, the PCB hole inspection machine further includes a light intensity sensor in communication with the controller 200. The controller 200 is further configured to control the variable light illumination unit 11 to emit a reference light. The light intensity sensor is configured to detect the intensity of the reference light passing through the small hole on the PCB to be inspected. By providing the light intensity sensor, the PCB hole inspection machine can automatically detect the aspect ratio of the small hole and cause the variable light illumination unit 11 to emit a matching inspection light, ensuring smooth and accurate inspection of the small hole, and further improving the efficiency of the PCB hole inspection.

[0073] The light intensity sensor is a sensor capable of detecting light intensity, such as a light sensor. During operation, the variable light illumination unit 11 emits reference light toward the printed circuit board to be tested. The light intensity sensor detects the intensity of the reference light that passes through the aperture on the printed circuit board to be tested. The controller 200 compares the detected reference light intensity with a light intensity-to-aspect ratio comparison table to determine the color of the test light that the variable light illumination unit 11 should emit. The light intensity-to-aspect ratio comparison table can be pre-loaded into the controller 200.

[0074] In addition to using a light intensity sensor to obtain the aperture aspect ratio, manual input of the aspect ratio can also be used to determine the color of the test light emitted by the variable light illumination unit 11. In addition to using a light intensity sensor to obtain the aperture aspect ratio and manually inputting the aspect ratio, the following technical solution can also be used: the controller 200 controls the variable light illumination unit 11 to emit reference light into the aperture on the printed circuit board to be inspected, and uses a light intensity sensor to detect the light intensity within the aperture. The aperture aspect ratio is then determined based on a light intensity-aspect ratio comparison table, thereby determining the color of the test light that the variable light illumination unit 11 should emit.

[0075] Optional, such as Figure 6 As shown, the image acquisition unit 12 includes a contact image processor 121 and an image acquisition card 122. The image acquisition card 122 is respectively connected to the contact image processor 121 and the controller 200. By configuring the contact image processor 121 and the image acquisition card 122, the image acquisition unit 12 can capture the detection light passing through the small hole and send the captured detection light information to the controller 200, so that the controller 200 can determine whether the small hole is blocked and whether the aperture size matches the designed value.

[0076] The contact image processor 121 is used to collect optical signal information of the detection light passing through the small holes on the printed circuit board to be inspected. The image acquisition card 122 converts the optical signal information collected by the contact image processor 121 into a digital signal and sends it to the controller 200, so that the controller 200 can process, compare and judge the collected optical signal information to determine whether the high aspect ratio small hole is blocked and whether the aperture size matches the design value.

[0077] Optionally, a plurality of groups of optical hole inspection assemblies 100 are arranged at intervals along the traveling direction of the printed circuit board to be inspected.

[0078] Existing printed circuit board (PCB) hole inspection machines only have one set of optical hole inspection assemblies 100. If the wall colors of high-aspect-ratio holes are inconsistent, a significant number of these holes may be missed, misidentified, or undetectable. This is especially true when the high-aspect-ratio holes are skewed, increasing the likelihood of missed or undetectable holes. Therefore, by spacing multiple sets of optical hole inspection assemblies 100 along the travel direction of the PCB to be inspected, these sets of optical hole inspection assemblies 100 can perform multiple inspections on the high-aspect-ratio holes at the same location and compare the inspection results, ensuring that all high-aspect-ratio holes are detected and improving the inspection accuracy of the PCB hole inspection machine. The spacing between two adjacent sets of optical hole inspection assemblies 100 can be determined based on the overall structural requirements of the PCB hole inspection machine and is not specifically limited by the present invention.

[0079] Among them, such as Figure 6 As shown, the dimming lighting units 11 of two adjacent sets of optical hole detection assemblies 100 are respectively positioned on either side of the printed circuit board to be inspected, and the optical paths of the detection light emitted by these two dimming lighting units 11 are parallel and non-overlapping. In other words, the light emitted by these two light sources does not interfere with each other, further improving detection accuracy.

[0080] By arranging the dimming lighting units 11 of two adjacent groups of optical hole testing assemblies 100 on both sides of the printed circuit board hole testing machine to be tested, and making the optical paths of the detection lights emitted by the two dimming lighting units 11 parallel to each other and without overlapping, the image acquisition units 12 of the two adjacent groups of optical hole testing assemblies 100 can only collect the detection lights emitted to the corresponding dimming lighting units 11, thereby ensuring the accuracy of the inspection results of each optical hole testing assembly 100.

[0081] The present invention also provides a method for detecting small holes on a printed circuit board, comprising:

[0082] Obtain the aspect ratio of small holes on printed circuit boards;

[0083] Select the color of the detection light according to the aspect ratio;

[0084] The light-variable lighting unit 11 is controlled to emit light of a corresponding color according to the selected detection light color.

[0085] Among them, there are two methods for obtaining the thickness-to-diameter ratio of a small hole on a printed circuit board. The first method is to manually input the thickness-to-diameter ratio; the second method is to use a reference light to pass through the small hole set on the printed circuit board to be tested, specifically including: obtaining the light intensity of the reference light, and then searching the database for the thickness-to-diameter ratio of the small hole based on the light intensity of the reference light.

[0086] Specifically, the controller 200 controls the variable light illumination unit 11 to emit a reference light toward the printed circuit board to be tested, and detects the illumination intensity of the reference light passing through the small hole on the printed circuit board to be tested through a light intensity sensor. Subsequently, the controller 200 searches the database (illumination intensity-thickness-to-diameter ratio comparison table) based on the illumination intensity of the reference light to obtain the thickness-to-diameter ratio of the small hole, and then obtains the color of the detection light based on a preset thickness-to-diameter ratio-light color comparison table. Finally, the controller controls the variable light illumination unit 11 to emit light of the corresponding color based on the selected color of the detection light.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A printed circuit board hole inspection machine, characterized in that: It includes an optical hole detection component and a controller, wherein the optical hole detection component includes a light-changing lighting unit and an image acquisition unit; The light-changing lighting unit is used to generate detection lights of different colors; The image acquisition unit is used to collect the detection light passing through the small hole set on the printed circuit board to be inspected; Also included is a light intensity sensor in communication with the controller; the controller is further configured to control the variable light illumination unit to emit reference light; the light intensity sensor is configured to detect the illumination intensity of the reference light passing through the small hole on the printed circuit board to be inspected; The controller compares the illumination intensity of the reference light collected by the light intensity sensor with the illumination intensity-aspect ratio comparison table, selects an illumination color that matches the aspect ratio of the aperture according to the aspect ratio, and controls the variable illumination unit to emit light of the corresponding color according to the selected illumination color; A plurality of groups of optical hole detection components are arranged at intervals along the traveling direction of the printed circuit board to be detected; The light-modulating illumination units of two adjacent groups of the optical hole detection components are respectively arranged on both sides of the printed circuit board to be detected, and the optical paths of the detection lights emitted by the two light-modulating illumination units are parallel to each other and have no overlap.

2. The printed circuit board hole inspection machine according to claim 1, characterized in that: The light-changing lighting unit includes an LED color-changing lamp and a light-uniform cover, and the LED color-changing lamp is communicatively connected to the controller.

3. The printed circuit board hole inspection machine according to claim 1, characterized in that: The variable light illumination unit includes a single color light source and a color wheel, and the color wheel can rotate around a rotation axis. A plurality of fluorescent coatings of different colors are provided on the color wheel, and the plurality of fluorescent coatings of different colors are arranged around the rotation axis.

4. The printed circuit board hole inspection machine according to claim 3, characterized in that: The variable light lighting unit also includes an outer shell and a motor for driving the color wheel to rotate. The single color light source and the color wheel are both located in the outer shell, and a light hole is provided on the outer shell for the detection light to pass through. The motor is communicatively connected to the controller.

5. The printed circuit board hole inspection machine according to claim 1, characterized in that: The image acquisition unit includes a contact image processor and an image acquisition card, and the image acquisition card is communicatively connected to the contact image processor and the controller respectively.

6. A method for detecting small holes on a printed circuit board, using the printed circuit board hole inspection machine according to any one of claims 1 to 5 for detection, characterized in that: include: Obtaining the aspect ratio of the small hole on the printed circuit board; selecting a color of the detection light according to the aspect ratio; The light-variable lighting unit is controlled to emit light of a corresponding color according to the selected detection light color.

7. The detection method according to claim 6, characterized in that Obtaining the aspect ratio of the small hole on the printed circuit board specifically includes: The illumination intensity of the reference light is obtained, and the aspect ratio of the small hole is obtained by searching in a database according to the illumination intensity of the reference light.

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