Device for improving back drilling hole defect detection efficiency

Abstract

The utility model relates to the technical field of PCB (Printed Circuit Board) detection devices, in particular to a device for improving back drilling hole defect detection efficiency, which comprises a camera unit for acquiring image information of an object to be detected; the lens end of the camera unit is connected with a telecentric lens; the telecentric lens further comprises a driving part, the driving part is connected with the aperture adjusting mechanism of the telecentric lens through a transmission mechanism, compared with the prior art that a fixed aperture mode is adopted, a fixed depth of field is adopted in the prior art, if the deepest depth of two drill holes is far smaller than the fixed depth of field, the performance of the lens is wasted, and the efficiency is low. The mode that the depth of field of the lens is controlled through the motor is adopted, when the deepest depth of the two drill holes is smaller than the fixed depth of field, the depth of field of the lens can be automatically adjusted to be matched with the deepest back drill hole, at the moment, compared with the fixed large depth of field, the light inlet amount of the lens can be increased, and therefore the exposure time of the camera can be shortened to improve the scanning efficiency; therefore, the concentricity detection efficiency of the second drill hole and the first drill hole is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of PCB detection devices, in particular to a device for improving the efficiency of back-drilling defect detection. Background Art

[0002] When manufacturing PCB, two-hole drilling and one-hole drilling are usually inspected to ensure the quality and accuracy of the drilling, as shown in the attached figure. Figure 1 As shown, the current detection device for two drill holes and one drill hole in PCB generally includes 1. a line scan camera; 2. a telecentric lens; 3. an upper light source; 4. an object to be measured; 5. a lower light source and other parts. The structure of the telecentric lens can refer to the telecentric lens equipped with a machine vision device disclosed in the prior art Chinese patent announcement number "CN107741623A", or a line scan double telecentric lens disclosed in Chinese patent announcement number "CN219533501 U".

[0003] Since the solution currently adopted in the concentricity detection of the second drill hole and the first drill hole is to use a lens with a fixed aperture, the depth of field of the lens and the amount of light entering per unit time are clearly unchangeable, and the larger the aperture, the lower the depth of field and the greater the amount of light entering per unit time. The depth of field and the amount of light entering per unit time are inversely correlated.

[0004] However, due to the use of a fixed aperture lens, the depth of field has been determined. Taking a depth of field of 5mm as an example, when the deepest depth of the second drilled hole to be detected is 2mm, the depth of field of 5mm is relatively wasteful. It is entirely possible to reduce the depth of field and increase the amount of light entering per unit time to reduce the exposure time of the camera and increase the scanning speed to improve efficiency. Based on this, in order to further optimize the applicability of the existing detection device, we propose a device to improve the efficiency of back-drilled hole defect detection. Utility Model Content

[0005] The utility model aims to solve the shortcomings of the prior art that the lens with fixed aperture has a fixed depth of field, resulting in waste of depth of field, and proposes a device for improving the efficiency of back drilling defect detection.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] Design a device to improve the efficiency of back drilling defect detection, including:

[0008] A camera unit for collecting image information of the object to be tested;

[0009] A telecentric lens is connected to the lens end of the camera unit;

[0010] It also includes a driving member, which is connected to the aperture adjustment mechanism of the telecentric lens through a transmission mechanism to control the depth of field range of the image obtained by the camera unit.

[0011] Furthermore, it also includes a bracket, and the camera unit, the telecentric lens and the driving component are all fixed on the bracket.

[0012] Furthermore, the driving member is a motor.

[0013] Furthermore, the transmission mechanism includes a transmission member fixed to the motor shaft end and the outer side of the aperture adjustment mechanism, and the two transmission members are transmitted via a rotating member.

[0014] Furthermore, the transmission member is configured as a pulley, and the rotating member is a synchronous belt sleeved between the two pulleys.

[0015] Furthermore, the bracket includes a longitudinal plate and two transverse plates vertically connected to the longitudinal plate, the driving member is fixed to the longitudinal plate, and the camera unit and the telecentric lens are respectively connected to the two transverse plates distributed vertically.

[0016] Furthermore, the camera unit is a line scan camera, and the telecentric lens is a double-sided telecentric lens.

[0017] The utility model proposes a device for improving the efficiency of back-drilled hole defect detection, and its beneficial effects are: compared with the existing solution adopting a fixed aperture method, the existing solution adopts a fixed depth of field. If the deepest depth of the two drilled holes is much smaller than the fixed depth of field, it will waste the performance of the lens and the efficiency is relatively low. By adopting a method of controlling the depth of field of the lens through a motor, when the deepest depth of the two drilled holes is smaller than the fixed depth of field, the depth of field of the lens can be automatically adjusted to adapt to the deepest back-drilled hole. At this time, compared with the fixed large depth of field, the amount of light entering the lens can be increased, thereby reducing the exposure time of the camera and improving the scanning efficiency, so as to improve the concentricity detection efficiency of the two drilled holes and the first drilled hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a detection device in the prior art;

[0019] Figure 2 The utility model is a schematic diagram of the structure of a device for improving the efficiency of back-drilling defect detection.

[0020] In the figure: 1. camera unit; 2. telecentric lens; 21. aperture adjustment mechanism; 3. driving member; 4. transmission mechanism; 41. rotating member; 5. bracket; 51. longitudinal plate; 52. transverse plate. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0022] Reference Figure 2 An embodiment of the utility model discloses a device for improving the efficiency of back-drilling defect detection, which is used to solve the problem that a lens with a fixed aperture is used in the current scheme for concentricity detection of two-drilling holes and one-drilling holes, and the depth of field of the lens and the amount of light entering per unit time are clearly unchangeable. Specifically, the device described in this embodiment includes a camera unit 1 for collecting image information of an object to be tested, and a telecentric lens 2 is connected to the lens end of the camera unit 1;

[0023] Specifically, in this embodiment, the camera unit 1 is a line scan camera, and the telecentric lens 2 is a bilateral telecentric lens, wherein the line scan camera is an industrial linear array scan camera, and the specific model can be adaptively selected by the relevant technical personnel. Similarly, the bilateral telecentric lens has been disclosed in the prior art and will not be elaborated on here. By adopting the bilateral telecentric lens, high-definition imaging can be achieved at a large aperture and a long working distance, and clear imaging can be achieved in an environment with low light illumination or continuous motion of the object.

[0024] It also includes a driving member 3, which is connected to the aperture adjustment mechanism 21 of the telecentric lens 2 through a transmission mechanism 4 to control the depth of field range of the image obtained by the camera unit 1.

[0025] In some embodiments, the utility model also includes a bracket 5, and the camera unit 1, the telecentric lens 2 and the driving member 3 are all fixed on the bracket 5. The design of the bracket 5 is used to support the above-mentioned components and the entire component. During the actual installation process, the above-mentioned components can be fixed at the required position through the bracket 5 to realize the detection of the PCB.

[0026] Furthermore, the bracket 5 in this embodiment includes a longitudinal plate 51 and two transverse plates 52 vertically connected to the longitudinal plate 51, the driving member 3 is fixed on the longitudinal plate 51, the camera unit 1 and the telecentric lens 2 are respectively connected to the two transverse plates 52 distributed up and down. Preferably, in this embodiment, the transverse plate 52 can be connected to the longitudinal plate 51 in a detachable manner, and specifically can be connected and fixed by bolts, which facilitates the assembly of the entire bracket 5.

[0027] On the basis of the above-mentioned embodiment, the driving member 3 in the embodiment of the utility model is a motor. In order to ensure the accuracy of control, the motor can be preferably configured as a servo motor, so that the rotation angle of the motor can be accurately controlled to improve the control stability of the aperture adjustment mechanism 21.

[0028] In some embodiments, the transmission mechanism 4 in the present invention includes a transmission member fixed to the motor shaft end and the outer side of the aperture adjustment mechanism 21 , and the two transmission members are transmitted via a rotating member 41 .

[0029] Further, in a preferred embodiment, the transmission member is configured as a pulley, and the rotating member 41 is a synchronous belt sleeved between the two pulleys. The synchronous belt and the pulley structure are conventional transmission structures, which will not be described in detail herein.

[0030] Of course, in other embodiments, technicians in the relevant field are obviously aware that the above-mentioned driving effect can also be achieved by using a sprocket and a chain transmission method. The specific solution can be adaptively selected by technicians in the relevant field and will not be elaborated here.

[0031] In addition, the utility model also proposes a method for improving the efficiency of back drilling defect detection, the method using the device described in the above scheme, specifically, the method comprises:

[0032] 10. Establish the corresponding relationship between the rotation distance of the driving member 3 and the telecentric lens 2.

[0033] The specific steps include:

[0034] 11. Control the rotary motor 3 to rotate, and rotate the aperture adjustment mechanism 21 on the telecentric lens 2 counterclockwise to the limit position through the rotating member 41, at which time the depth of field is maximum;

[0035] 12. Use the depth of field ruler to measure the depth of field of telecentric lens 2 at this time, which is d1. The position of the motor is recorded as 0mm, and the movement interval is set to gmm;

[0036] 13. Control the motor to move clockwise by gmm. At this time, the position of the motor is gmm. Use the depth of field ruler to measure the depth of field of telecentric lens 2, which is d2.

[0037] 14. Control the motor to move clockwise gmm again. At this time, the position of the motor is 2*gmm. Use the depth of field ruler to measure the depth of field of the telecentric lens 2 at this time, which is d3. Similarly, when the depth of field reaches the adjustable limit, record the current rotation distance of the rotating motor 3 and the depth of field of the bilateral telecentric lens 2.

[0038] 15. With the position of the rotating motor that moves multiple times as the horizontal coordinate and the depth of field of the corresponding bilateral telecentric lens 2 as the vertical coordinate, a straight line y=ax+b is fitted;

[0039] 20. Load the data files of the second and first drill holes into the software. The information of each hole contains the depth value of the second drill hole;

[0040] The specific steps include:

[0041] 21. The depth of each secondary borehole is d n (n=1,2,3,........n), the deepest second drilling depth is calculated as maxdmm according to the depth of each second drilling hole;

[0042] 22. Substitute y=maxd into the equation y=ax+b. The calculated x is the position the motor needs to move to.

[0043] 23. After the motor is rotated to this position, an aperture position with a proper depth of field can be obtained, thereby adjusting the exposure time of the line scan camera 1 to improve the detection efficiency.

[0044] In summary, compared with the existing scheme that adopts a fixed aperture, the existing scheme adopts a fixed depth of field. If the deepest depth of the two drilled holes is much smaller than the fixed depth of field, it will waste the performance of the lens and the efficiency will be relatively low. However, the present invention adopts a method of controlling the depth of field of the lens through a motor. When the deepest depth of the two drilled holes is less than the fixed depth of field, the depth of field of the lens can be automatically adjusted to adapt to the deepest back-drilled hole. At this time, compared with the fixed large depth of field, the amount of light entering the lens can be increased, thereby reducing the exposure time of the camera and improving the scanning efficiency, so as to improve the concentricity detection efficiency of the two drilled holes and the first drilled hole.

[0045] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0046] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0047] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A device for improving the efficiency of back-drilling defect detection, characterized in that: include: A camera unit (1) for collecting image information of the object to be tested; A telecentric lens (2) is connected to the lens end of the camera unit (1); It also comprises a driving member (3), wherein the driving member (3) is connected to the aperture adjustment mechanism (21) of the telecentric lens (2) via a transmission mechanism (4) so ​​as to control the depth of field range of an image obtained by the camera unit (1).

2. The device for improving back-drilling defect detection efficiency according to claim 1, characterized in that: It also comprises a bracket (5), and the camera unit (1), the telecentric lens (2) and the driving member (3) are all fixed on the bracket (5).

3. A device for improving back drilling defect detection efficiency according to claim 1 or 2, characterized in that: The driving component (3) is a motor.

4. The device for improving back-drilling defect detection efficiency according to claim 3, characterized in that: The transmission mechanism (4) comprises a transmission member fixed to the motor shaft end and the outside of the aperture adjustment mechanism (21), and transmission is performed between the two transmission members via a rotating member (41).

5. The device for improving back-drilling defect detection efficiency according to claim 4, characterized in that: The transmission member is configured as a pulley, and the rotating member (41) is a synchronous belt sleeved between the two pulleys.

6. The device for improving back-drilling defect detection efficiency according to claim 2, characterized in that: The bracket (5) comprises a longitudinal plate (51) and two transverse plates (52) vertically connected to the longitudinal plate (51), the driving member (3) is fixed on the longitudinal plate (51), and the camera unit (1) and the telecentric lens (2) are respectively connected to the two transverse plates (52) distributed above and below.

7. The device for improving back-drilling defect detection efficiency according to claim 1, characterized in that: The camera unit (1) is a line scan camera, and the telecentric lens (2) is a double-sided telecentric lens.

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