Displacement imaging device suitable for leadframe detection

Abstract

The utility model belongs to the field of machine vision, concretely is a kind of displacement imaging device suitable for lead frame detection, including camera, displacement drive mechanism, imaging light path and light source, the light source is low angle light source, the low angle light source is set above measured object, the low angle light source is single layer strip light or multilayer strip light or single layer ring light or multilayer ring light.The utility model because light source distance measured object is very close, incident light illumination to gold line time, most light meets the reflection theorem of light, reflected light is towards upper, i.e.the direction of camera, light can be smoothly captured by imaging system, and gold line can be imaged.The utility model further expands the application scene of displacement imaging to gold line detection field, and gold line detection field is a hundred billion level market, and market prospect is wide.

Description

Technical Field

[0001] This utility model belongs to the field of machine vision, and in particular relates to a displacement imaging device suitable for lead frame detection. Background Technology

[0002] 3D reconstruction technology is an observation technique aimed at reconstructing the surface contours or internal structure of an object using computers. Optical methods are widely used due to their non-contact, non-destructive, and high-speed characteristics. Any imaging optical system, due to the presence of Airy disks, has a depth-of-field limitation. Depth of field refers to the range of distances from which objects can be clearly seen. For example, when using a DSLR camera to photograph a person, the background scenery will be blurred because it is outside the camera's depth of field. Utilizing the principle of limited depth of field, a relationship between distance and zoom is established.

[0003] Figure 1 This paper demonstrates a common displacement imaging device based on a microscopy system. The device mainly comprises a camera 101, a microscope tube 102, a piezoelectric displacement device 105, a microscope objective 106, and a light source 107. Its workflow is as follows: the light source 107 is illuminated, the piezoelectric displacement device 105 moves the microscope objective 106 one step upwards, and then the camera 101 acquires an image. This process is repeated to obtain images of the microscope objective 106 at multiple heights. For example, when the objective focal plane moves from 1044 to 1041, a point A on a textured object 103 is selected as the research object. At each focal plane position, a sharpness change graph 108 is obtained using a sharpness algorithm. The X-axis of the sharpness graph 108 represents sharpness, and the Y-axis represents the height. Since point A falls near focal plane 1042, it can be seen from the sharpness graph 108 that the sharpness value is highest near focal plane 1042. Therefore, the height of point A is considered to be at focal plane 1042.

[0004] Depth-of-field fusion technology determines whether a pixel is on the focal plane based on the sharpness (or clarity) of a local area of ​​an image. In leadframe applications, there are not only mirror-like grains but also suspended gold wires. The gold wires, in situations like... Figure 1 Under the illumination of light source 107, the image appears completely black, making it impossible to determine its sharpness information across multiple focal planes, resulting in signal loss during the final height reconstruction. Currently, mainstream methods for gold wire detection remain at the 2D detection level. However, with increasingly stringent process quality standards, traditional 2D detection is no longer sufficient, necessitating higher-dimensional detection.

[0005] Figure 2 This is a schematic diagram of the CMOS after wire bonding, in which the CMOS body 302 is electrically connected to the substrate 303 by bonding with gold wire 301. Figure 3The right image is a side view of the left image. It can be seen from the image that the gold wire 301 has a large curvature, and the substrate 303 is usually a flexible board with very weak texture characteristics.

[0006] Figure 3 For use Figure 1 The system in the middle emits incident light beam 310 and incident light beam 320 from light source 107 onto gold wire 301. It was found that reflected light beam 311 and reflected light beam 321 could not return to microscope objective 106, and the signal was lost.

[0007] In addition, in power device modules, IGBT bonding wires are usually made of aluminum wires, and there are also cases where light cannot return due to the large slope. Utility Model Content

[0008] The technical problem to be solved by this invention is to design a displacement imaging device suitable for lead frame detection, overcome the difficulties of gold wire imaging in the prior art, and thus solve the existing technical problem.

[0009] To solve the above-mentioned technical problems, this utility model provides a displacement imaging device suitable for lead frame detection, including a camera, a displacement driving mechanism, an imaging optical path and a light source. The light source is a low-angle light source, which is positioned above the object being measured. The low-angle light source is a single-layer strip light, a multi-layer strip light, a single-layer ring light, or a multi-layer ring light.

[0010] Furthermore, in this invention, the low-angle light source includes four sets of first rays that are 90 degrees apart from each other.

[0011] Furthermore, in this invention, the low-angle light source also includes four sets of second lights at 90 degrees to each other. The length of the second light is less than the length of the first light, and the second light is positioned above the first light, that is, the position of the second light is higher than that of the first light.

[0012] Furthermore, in this invention, the low-angle light source includes eight sets of third light rays, which are evenly distributed in a circular pattern.

[0013] Furthermore, in this invention, the low-angle light source also includes eight groups of fourth light rays, which are evenly distributed in a circular pattern. The length of each fourth light ray is less than the length of the third light ray, and the fourth light ray is positioned above the third light ray, meaning that the position of the fourth light ray is higher than that of the third light ray.

[0014] Furthermore, in this invention, the low-angle light source includes a first ring light source.

[0015] Furthermore, in this invention, the low-angle light source also includes a second ring light source, the diameter of which is smaller than that of the first ring light source, and the second ring light source is positioned above the first ring light source, that is, the position of the second ring light source is higher than that of the first ring light source.

[0016] Compared with traditional depth-of-field fusion devices in microscopic systems, this invention has the following technical advantages: This invention relates to a displacement imaging device for lead frame detection. By using a low-angle light source, and because the light source is very close to the object being measured, when the incident light illuminates the gold wire, most of the light rays conform to the law of reflection, and the reflected light is directed upwards, i.e., towards the camera. This light can be easily captured by the imaging system, and the gold wire can be imaged. This invention further expands the application scenarios of displacement imaging to the field of gold wire detection, a market worth tens of billions of dollars. All CMOS sensors use gold wire bonding, and CMOS is currently the photosensitive component in all mobile phone cameras; it is an indispensable and core component with a broad market prospect. Attached Figure Description

[0017] The specific embodiments of this utility model will be further explained below with reference to the accompanying drawings.

[0018] Figure 1 This is a schematic diagram and a resolution map of point A for a displacement imaging device based on a microscopic system in the prior art.

[0019] Figure 2 This is a schematic diagram of CMOS wire bonding in the prior art.

[0020] Figure 3 for Figure 1 A schematic diagram of the optical path of the device used in gold wire detection.

[0021] Figure 4(a) is a schematic diagram of the low-angle light source of the displacement imaging device based on the microscopic system in Example 1.

[0022] Figure 4(b) is a schematic diagram of the low-angle light source of the displacement imaging device based on the microscopic system in Example 2.

[0023] Figure 4(c) is a schematic diagram of the low-angle light source of the displacement imaging device based on the microscopic system in Example 3.

[0024] Figure 4(d) is a schematic diagram of the low-angle light source of the displacement imaging device based on the microscopic system in Example 4.

[0025] Figure 4(e) is a schematic diagram of the low-angle light source of the displacement imaging device based on the microscopic system in Example 5.

[0026] Figure 4(f) is a schematic diagram of the low-angle light source of the displacement imaging device based on the microscopic system of this invention in the embodiment.

[0027] Figure 5 This is a schematic diagram of the optical path of the displacement imaging device based on a microscopic system of this invention applied to gold wire detection.

[0028] In the picture: 101—Camera; 102—Tube endoscope; 103—Object to be tested; 1041, 1042, 1043, 1044 — Positions of the objective lens focal plane; 105—Piezoelectric displacement device; 106—Microscope objective; 107—Light source; 108—Resolution Chart; 301—Gold Thread; 302—The core of CMOS; 303—Substrate; 310—Incident ray one; 320—Incident ray two; 311—Reflected ray one; 321—Reflected ray two; 1021—The First Light; 1022—The Second Light; 2021—The Third Light; 2022—The Fourth Light; 3021—First Ring Light Source; 3022—Second Ring Light Source; 100—The surface where the object being measured is located; 404—Incident ray; 405—Reflected light. Detailed Implementation Example 1

[0029] Referring to Figure 4(a), the left image in Figure 4(a) is a top view and the right image is a side view. The displacement imaging device for lead frame detection in this embodiment includes a camera, a displacement driving mechanism, an imaging optical path, and a light source. The light source is a low-angle light source, which is set above the object being measured. When the imaging device of this embodiment acquires images, the low-angle light source illuminates the object being measured, and the displacement driving mechanism performs linear adjustment to acquire multiple images at different heights.

[0030] In this embodiment, preferably, the low-angle light source is a single-layer strip light.

[0031] In this embodiment, preferably, the low-angle light source includes four sets of first light rays 1021 arranged at 90 degrees to each other. The first light rays 1021 are set above the surface 100 where the object being measured is located. In Figure 4(a), the left image is a top view and the right image is a side view.

[0032] The displacement imaging device for lead frame detection in this embodiment is suitable for situations where the gold wire only has horizontal and vertical directions. Example 2

[0033] Referring to Figure 4(b), where the left image is a top view and the right image is a side view, the difference between the displacement imaging device for lead frame detection in this embodiment and the imaging device in Embodiment 1 is that the low-angle light source in this embodiment is a multi-layer strip light, and the low-angle light source also includes four sets of second light rays 1022 that are 90 degrees apart. The length of the second light ray 1022 is less than the length of the first light ray 1021. The second light ray 1022 is positioned above the first light ray 1021, that is, the position of the second light ray 1022 is higher than that of the first light ray 1021. The first light ray 1021 is positioned above the surface 100 where the object being measured is located. The remaining technical features are the same as those of the displacement imaging device for lead frame detection in Embodiment 1.

[0034] The displacement imaging device for lead frame detection in this embodiment is suitable for situations where gold wires have multiple layers of varying heights. Example 3

[0035] Referring to Figure 4(c), where the left image is a top view and the right image is a side view, the difference between the displacement imaging device for lead frame detection in this embodiment and the imaging device in Embodiment 1 is that the low-angle light source in this embodiment includes 8 sets of third light 2021, which are evenly distributed in a circular pattern. The third light 2021 is positioned above the surface 100 of the object being measured. The remaining technical features are the same as those in the displacement imaging device for lead frame detection in Embodiment 1.

[0036] The displacement imaging device for lead frame detection in this embodiment is suitable for situations where the azimuth angle of the gold wire is not fixed and is relatively messy. Therefore, multiple angles of illumination are required. Compared with the low-angle light source in Embodiment 1, this embodiment increases the illumination to 8 angles. Example 4

[0037] Referring to Figure 4(d), where the left image is a top view and the right image is a side view, the difference between the displacement imaging device for lead frame detection in this embodiment and the imaging device in Embodiment 3 is that the low-angle light source in this embodiment is a multi-layer strip light, and the low-angle light source also includes 8 groups of fourth light 2022. The 8 groups of fourth light 2022 are evenly distributed in a circle. The length of the fourth light 2022 is less than the length of the third light 2021. The fourth light 2022 is positioned above the third light 2021, that is, the position of the fourth light 2022 is higher than that of the third light 2021. The third light 2021 is positioned above the surface 100 where the object being measured is located. The remaining technical features are the same as those of the displacement imaging device for lead frame detection in Embodiment 3.

[0038] The displacement imaging device for lead frame detection in this embodiment is suitable for scenarios where the azimuth angle of the gold wire is not fixed, it is relatively messy, and the gold wire has multiple layers of varying heights, requiring illumination from multiple angles. This embodiment increases the illumination to a double-layer illumination with eight angles. Example 5

[0039] Referring to Figure 4(e), where the left image is a top view and the right image is a side view, the difference between the displacement imaging device for lead frame detection in this embodiment and the imaging device in Embodiment 1 is that the low-angle light source in this embodiment is a single-layer ring light. The low-angle light source in this embodiment includes a first ring light source 3021, which is positioned above the surface 100 where the object being measured is located. The remaining technical features are the same as those of the displacement imaging device for lead frame detection in Embodiment 1.

[0040] The displacement imaging device for lead frame detection in this embodiment is suitable for situations where the direction of gold wire bonding is irregular. Example 6

[0041] Referring to Figure 4(f), where the left image is a top view and the right image is a side view, the difference between the displacement imaging device for lead frame detection in this embodiment and the imaging device in embodiment 5 is that the low-angle light source in this embodiment is a multi-layer ring light, and the low-angle light source also includes a second ring light source 3022. The diameter of the second ring light source 3022 is smaller than the diameter of the first ring light source 3021. The second ring light source 3022 is located above the first ring light source 3021, that is, the position of the second ring light source 3022 is higher than that of the first ring light source 3021. The first ring light source 3021 is located above the surface 100 where the object being measured is located. The remaining technical features are the same as those of the displacement imaging device for lead frame detection in embodiment 5.

[0042] The displacement imaging device for lead frame detection in this embodiment is suitable for situations where the gold wire bonding direction is irregular and there are multiple layers of gold wires of varying heights.

[0043] The displacement imaging device for lead frame detection of the present invention utilizes a low-angle light source, placing the light source very close to the object being measured. When the incident light illuminates the gold wire, most of the light rays conform to the law of reflection, and the reflected light is directed upwards, i.e., towards the camera. This allows the light rays to be easily captured by the imaging system, enabling the gold wire to be imaged. Figure 5 As shown, taking the displacement imaging device for lead frame detection in Embodiment 1 as an example, since the first light 1021 is very close to the object being measured, when the incident light 404 illuminates the gold wire 301, most of the light conforms to the law of reflection, and the reflected light 405 is directed upwards, i.e., towards the camera. The light can be successfully captured by the imaging system, and the gold wire 301 can be imaged. This invention further expands the application scenario of displacement imaging to the field of gold wire detection, which is a market worth tens of billions of yuan with broad market prospects.

[0044] Many specific details have been set forth in the above description to provide a full understanding of this utility model. However, the above description is only a preferred embodiment of this utility model, and this utility model can be implemented in many other ways different from those described herein. Therefore, this utility model is not limited to the specific embodiments disclosed above. Furthermore, any person skilled in the art can make many possible variations and modifications to the technical solution of this utility model using the methods and techniques disclosed above, or modify it into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of this utility model. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model, without departing from the content of the technical solution of this utility model, shall still fall within the protection scope of the technical solution of this utility model.

Claims

1. A displacement imaging device suitable for lead frame detection, characterized in that: It includes a camera, a displacement driving mechanism, an imaging optical path, and a light source. The light source is a low-angle light source, which is positioned above the object being measured. The low-angle light source can be a single-layer strip light, a multi-layer strip light, a single-layer ring light, or a multi-layer ring light.

2. The displacement imaging device for lead frame detection according to claim 1, characterized in that: The low-angle light source includes four sets of first rays (1021) that are 90 degrees apart from each other.

3. The displacement imaging device for lead frame detection according to claim 2, characterized in that: The low-angle light source also includes four sets of second light rays (1022) that are 90 degrees apart from each other. The length of the second light ray (1022) is less than the length of the first light ray (1021), and the second light ray (1022) is positioned above the first light ray (1021).

4. The displacement imaging device for lead frame detection according to claim 1, characterized in that: The low-angle light source includes eight sets of third light rays (2021), which are evenly distributed in a circular pattern.

5. The displacement imaging device for lead frame detection according to claim 4, characterized in that: The low-angle light source also includes 8 sets of fourth light rays (2022), which are evenly distributed in a circular pattern. The length of each fourth light ray (2022) is less than the length of the third light ray (2021), and the fourth light ray (2022) is positioned above the third light ray (2021).

6. The displacement imaging device for lead frame detection according to claim 1, characterized in that: The low-angle light source includes a first ring light source (3021).

7. The displacement imaging device for lead frame detection according to claim 6, characterized in that: The low-angle light source also includes a second ring light source (3022), the diameter of which is smaller than that of the first ring light source (3021), and the second ring light source (3022) is positioned above the first ring light source (3021).

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