Triangulation device
Through the triangulation device with a switchable multi-lens design, the detection accuracy and speed compatibility problems are solved, and are compatible with the surface fluctuations of different objects to be measured, achieving efficient triangulation.
Patent Information
- Application Number
- CN202422322269.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-23
- Publication Date
- 2025-08-01
- Estimated Expiration
- 2034-09-23
AI Technical Summary
The existing triangulation scheme is difficult to compatible with detection accuracy and speed. The reflective triangulation scheme is prone to loss of signals when measuring non-planar objects. In addition, the large-limiting angle lens has the problem of large size and short working distance, so it is not compatible with multiple lenses.
The switchable multi-lens design is adopted, including switchable first and second detection objective lens groups. Through the full focus setting and the special light-catching angle design of the light-catching and objective lens, it ensures the compatibility of detection accuracy and speed, and solves the working distance problem of the large light-catching angle lens through lens switching.
It achieves the improvement of detection speed while ensuring detection accuracy, reduce signal loss, compatible with the detection requirements of objects to be measured in different sizes, and maximizes yield.
Smart Images
Figure CN223179500U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of optics, in particular to a triangulation device. Background Art
[0002] There are two types of triangulation schemes: reflective and scattering. The scattering triangulation scheme cannot detect mirror surfaces, but when the surface profile of a rough surface fluctuates greatly, there are still many height signals; the reflective triangulation scheme can detect mirror surfaces, but when the surface profile of the object to be measured fluctuates greatly, many height signals of the object to be measured will be lost. When the object to be measured has both a mirror surface and a rough surface, only the reflective triangulation scheme can be selected.
[0003] However, the existing triangulation schemes have the following problems:
[0004] 1. In terms of height detection, the detection accuracy and detection speed are inversely proportional. It is necessary to improve the detection speed as much as possible on the premise of ensuring accuracy. In the case of a single-lens design, it is impossible to well meet the requirements of productivity and accuracy.
[0005] 2. When the reflective triangulation scheme measures a non-planar object, it is affected by the curvature change of the surface of the object to be measured. When measuring an object with a large surface undulation change, a large number of points will be lost. At this time, a large light-receiving angle lens is required to collect the scattered light after passing through the object to be measured to reduce the point cloud loss. However, the focal depth range of a large light-receiving angle objective lens is small, and when the defocus exceeds a certain focal depth range, the energy will quickly disperse, which will also cause point cloud loss.
[0006] 3. The design principle of the Scheimpflug lens can ensure that one lens is not defocused, but for a high-power lens, the camera angle designed under the Scheimpflug principle is very large, and when switching to another high-power objective lens, due to different magnifications, the difference in the designed camera angles is very large, and it is impossible to be compatible with two or more lenses.
[0007] 4. The large light-receiving angle objective lens also has the problems of a large lens size and a short working distance. Summary of the Utility Model
[0008] In view of this, the purpose of the utility model is to provide a triangulation device, which can accommodate more detection accuracy requirements through the design of a switchable multi-lens, so as to maximize productivity.
[0009] In a first aspect, an embodiment of the utility model provides a triangulation device, which includes: a lighting source, a detection objective lens group and a detector; the lighting source is used to generate a lighting beam and incident on the surface of the object to be measured; the detection objective lens group includes a switchable first detection objective lens group and a second detection objective lens group, and the first detection objective lens group and the second detection objective lens group have different focal lengths; the detection objective lens group is used to receive the spot signal containing the height information of the object to be measured; the detector is used to analyze the spot signal.
[0010] In an alternative embodiment of the present application, the first detection objective lens group and the second detection objective lens group are switched according to the sizes of the objects to be measured.
[0011] In an alternative embodiment of the present application, the above-mentioned triangulation device further includes: a lens barrel, which is arranged between the detection objective lens group and the detector.
[0012] In an alternative embodiment of the present application, the above-mentioned lens barrel, detection objective lens group and illumination beam are set to be parfocal.
[0013] In an alternative embodiment of the present application, the reflected light rays of the illumination beam reflected from the surface of the object to be measured are irradiated onto the focal plane of the detection objective lens group.
[0014] In an alternative embodiment of the present application, the above-mentioned illumination beam is perpendicular to the detection objective lens group.
[0015] In an alternative embodiment of the present application, the incident angle of the above-mentioned illumination beam is a first angle, and the included angle between the detection objective lens group and the surface of the object to be measured is a second angle; the sum of the first angle and the second angle is 90°.
[0016] In an alternative embodiment of the present application, the light collection angle of the above-mentioned detection objective lens group is greater than or equal to the difference between the first angle and the second angle.
[0017] In an alternative embodiment of the present application, the above-mentioned detection objective lens group further includes: an objective lens switcher, and the distance from the objective lens mounting port of the objective lens switcher to the focal plane of the detection objective lens group is fixed.
[0018] In an alternative embodiment of the present application, the above-mentioned detector is used to determine the height of the object to be measured based on the spot interval of the spot signal imaged on the detector, the focal length of the lens barrel, the focal length of the detection objective lens group and the second angle.
[0019] The embodiments of the present utility model bring the following beneficial effects:
[0020] The embodiments of the present utility model provide a triangulation device, wherein an illumination source is used to generate an illumination beam and incident it onto the surface of the object to be measured; the detection objective lens group includes a switchable first detection objective lens group and a second detection objective lens group, and the first detection objective lens group and the second detection objective lens group have different focal lengths; the detection objective lens group is used to receive the spot signal containing the height information of the object to be measured; the detector is used to analyze the spot signal. The triangulation device can meet more detection accuracy requirements through the design of switchable multiple lenses, thereby maximizing the production rate.
[0021] Other features and advantages of the present disclosure will be described in the subsequent description, or, some features and advantages can be inferred from the description or determined without doubt, or can be known by implementing the above technologies of the present disclosure.
[0022] To make the above objects, features, and advantages of the present disclosure more apparent and understandable, the following provides preferred embodiments in conjunction with the accompanying drawings and describes them in detail as follows. Brief Description of the Drawings
[0023] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0024] Figure 1 Structural schematic diagram of a triangulation device provided by an embodiment of the present utility model;
[0025] Figure 2 Schematic diagram of the detection principle of a triangulation device provided by an embodiment of the present utility model;
[0026] Figure 3 Schematic diagram of the principle for calculating the height of the object to be measured by a triangulation device provided by an embodiment of the present utility model.
[0027] Reference numerals: 101 - illumination source; 102 - object to be measured; 103 - detection objective lens group; 104 - lens barrel; 105 - detector; 201 - illumination beam; 301 - objective lens switcher. Detailed Embodiments
[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the following will clearly and completely describe the technical solutions of the present utility model in conjunction with the drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present utility model belong to the scope of protection of the present utility model.
[0029] The triangulation scheme includes two types: reflective and scattering. The scattering triangulation scheme cannot detect specular surfaces, but when the surface profile of a rough surface fluctuates greatly, there are still many height signals; the reflective triangulation scheme can detect specular surfaces, but when the surface profile of the object to be measured fluctuates greatly, many height signals of the object to be measured will be lost. When the object to be measured has both a specular surface and a rough surface, only the reflective triangulation scheme can be selected.
[0030] However, the existing triangulation schemes have the following problems:
[0031] 1. In height detection, the detection accuracy is inversely proportional to the detection speed. It is necessary to improve the detection speed as much as possible on the premise of ensuring accuracy. In the case of a single-lens design, it is impossible to well accommodate the requirements of production rate and accuracy.
[0032] 2. In the reflection type triangulation scheme, when measuring non-planar objects, affected by the curvature change of the surface of the object to be measured, a large number of points will be lost when measuring objects with large surface undulation changes. At this time, a large light-receiving angle lens is required to collect the scattered light after passing through the object to be measured to reduce the loss of point cloud. However, the focal depth range of the large light-receiving angle objective lens is small, and when the defocus exceeds a certain focal depth range, the energy will quickly disperse, which will also cause the loss of point cloud.
[0033] 3. The design principle of the Scheimpflug lens can ensure that a lens is not defocused. However, for high-power lenses, the camera angle under the Scheimpflug principle design is very large, and when switching to another high-power objective lens, due to different magnifications, the difference in the camera design angle is very large, and it is impossible to be compatible with two or more lenses.
[0034] 4. The large light-receiving angle objective lens also has problems of large lens size and short working distance.
[0035] Based on this, a triangulation device provided by an embodiment of the present utility model specifically provides a triangulation scheme with multi-lens switching, which can accommodate the surface undulation of the object to be measured as much as possible to reduce signal loss and restore the height information of the object to be measured; through the design of switchable multi-lenses to accommodate more detection accuracy requirements, so as to maximize the production rate; through special lighting and objective lens light-receiving angle design to ensure that the object to be measured is not defocused; and at the same time ensure the working distance of the large light-receiving angle lens.
[0036] For the convenience of understanding this embodiment, first, a triangulation device disclosed in an embodiment of the present utility model will be introduced in detail.
[0037] Embodiment 1:
[0038] An embodiment of the present utility model provides a triangulation device. Refer to Figure 1 the structural schematic diagram of a triangulation device shown. The triangulation device includes: a lighting source 101, a detection objective lens group 103, and a detector 105; the lighting source 101 is used to generate a lighting beam and incident on the surface of the object to be measured 102; the detection objective lens group 103 includes a switchable first detection objective lens group and a second detection objective lens group, and the first detection objective lens group and the second detection objective lens group have different focal lengths; the detection objective lens group 103 is used to receive the spot signal containing the height information of the object to be measured 102; the detector 105 is used to analyze the spot signal.
[0039] The detection objective lens group in this embodiment includes a switchable first detection objective lens group and a second detection objective lens group. In some embodiments, the first detection objective lens group and the second detection objective lens group are switched according to the size of the object to be measured. This embodiment can meet more detection accuracy requirements through a design with switchable multiple lenses, thereby maximizing the production rate.
[0040] The triangulation device in this embodiment is used for 3D detection of semiconductors, specifically for the detection of bumps (i.e., spheres) on the surface of wafers. According to the shape characteristics of the spheres, the smaller the size of the spheres, the steeper the top arc (i.e., the larger the arc curvature). In this scenario, a low-magnification lens is required for detection to achieve the detection of small-sized spheres and avoid missed detections. Therefore, in order to achieve no missed detections and improve the detection accuracy, a low-magnification lens is preferably selected. However, under the condition of large-sized spheres, a low-magnification lens is likely to result in a relatively high detection time cost, and the arc curvature at the top of the large-sized spheres is smaller than that of the small-sized spheres. At this time, in order to improve the detection efficiency, it is necessary to switch to a high-magnification lens for corresponding detection.
[0041] Therefore, the triangulation device provided in this embodiment can be switched according to different conditions of large and small sizes to achieve 3D detection of spheres of different sizes. In addition, the sphere size and the selection of the precision lens can be set based on the actual bumps on different production lines, which will not be elaborated in this embodiment.
[0042] As Figure 1 shown, in some embodiments, the above-mentioned triangulation device further includes: a lens barrel 104, and the lens barrel 104 is arranged between the detection objective lens group 103 and the detector 105. The spot signal can be imaged on the detector through the lens barrel.
[0043] In some embodiments, the above-mentioned lens barrel, detection objective lens group, and illumination beam are set to be parfocal.
[0044] In this embodiment, by setting the lens barrel, detection objective lens group, and illumination beam to be parfocal, it can be ensured that there is no defocusing after switching the detection objective lens group. As Figure 1 shown, in some embodiments, the incident angle of the illumination beam is the first angle, and the included angle between the detection objective lens group and the object to be measured is the second angle; the sum of the first angle and the second angle is 90°.
[0045] The illumination source can project a line spot onto the object to be measured at the first angle α, and the spot signal containing height information is received by the detection objective lens group. The included angle between the detection objective lens group and the object to be measured is the second angle β. The incident spot angle and the principal ray angle of the detection objective lens group are 90° (i.e., the first angle α + the second angle β = 90°). The spot signal received by the detection objective lens group is imaged on the detector through the lens barrel and can be analyzed into 3D information to determine the height of the object to be measured.
[0046] In this embodiment, the incident light spot angle and the chief ray angle of the detection objective lens group are 90°, which can ensure that the object to be measured is not out of focus; at the same time, the working distance of the large light collection angle lens is ensured.
[0047] An embodiment of the present invention provides a triangulation device. The illumination source is used to generate an illumination beam and incident on the surface of the object to be measured; the detection objective lens group includes a switchable first detection objective lens group and a second detection objective lens group, and the first detection objective lens group and the second detection objective lens group have different focal lengths; the detection objective lens group is used to receive the light spot signal containing the height information of the object to be measured; the detector is used to analyze the light spot signal. The triangulation device can meet more detection accuracy requirements through the design of switchable multiple lenses, so as to maximize the production rate.
[0048] Embodiment 2:
[0049] Another triangulation device is provided in an embodiment of the present invention, which can be referred to Figure 2 See the schematic diagram of the detection principle of a triangulation device shown. The illumination beam 201 emitted by the illumination source is incident on the object to be measured 102 at an incident angle (i.e., the first angle) α, and is reflected by the object to be measured 102 and the substrate.
[0050] In some embodiments, the reflected light of the illumination beam reflected by the surface of the object to be measured is irradiated onto the focal plane of the detection objective lens group.
[0051] In some embodiments, the illumination beam is perpendicular to the detection objective lens group.
[0052] As Figure 2 shown, since the illumination beam 201 and the detection objective lens group 103 are at 90°, the reflected light rays from the object to be measured 102 are all on the focal plane of the detection objective lens group 103.
[0053] In some embodiments, the light collection angle of the detection objective lens group is greater than or equal to the difference between the first angle and the second angle.
[0054] As Figure 2 shown, in order to ensure compatibility between the mirror object to be measured and the rough object to be measured, it is necessary to ensure that the light collection angle θ of the objective lens satisfies: the first angle ɑ - the second angle β ≤ θ the light collection angle of the objective lens, and a sufficient working distance is reserved to ensure no interference in the object space.
[0055] Embodiment 3:
[0056] Another triangulation device is provided in an embodiment of the present invention, which can be referred to Figure 3 See the schematic diagram of the principle of calculating the height of the object to be measured of a triangulation device shown.
[0057] In some embodiments, the detection objective lens group further includes: an objective lens switcher, and the distance from the objective lens mounting port of the objective lens switcher to the focal plane of the detection objective lens group is fixed.
[0058] As Figure 3 shown, the above detection objective lens group further includes: an objective lens switch 301. The distance from the objective lens mounting port of the objective lens switch 301 to the objective lens focal plane is the same, so that different focal length objective lenses can still be used normally after switching.
[0059] In some embodiments, the detector is used to determine the height of the object to be measured based on the spot signal imaging, the spot interval on the detector, the focal length of the lens barrel, the focal length of the detection objective lens group, and the second angle.
[0060] As Figure 3 shown, the spot interval of the object to be measured with height h on the detector 105 after imaging is (f1 / f2)×(h / sinβ), where f1 is the focal length of the lens barrel, f2 is the focal length of the detection objective lens group. After switching the detection objective lens group, f2 changes, the imaging magnification changes accordingly, and the detection sensitivity and light collection ability change.
[0061] Therefore, in this embodiment, the height of the object to be measured can be determined based on the spot signal imaging, the spot interval on the detector, the focal length of the lens barrel, the focal length of the detection objective lens group, and the second angle. By switching the detection objective lens groups with different focal lengths, the detection sensitivity and light collection ability can be changed.
[0062] For the above triangulation device provided by the embodiment of the present invention, the first angle α + the second angle β = 90° can ensure that the object to be measured is not out of focus. The specular reflection light of the incident light being received by the detection objective lens group can ensure that the specular reflection object (i.e., the object to be measured) can be measured. The parfocal objective lens can ensure that it is not out of focus after switching the detection objective lens group.
[0063] In summary, the above triangulation device provided by the embodiment of the present invention can not only accommodate more detection accuracy requirements through the design of switchable multiple lenses, so as to maximize the production rate; but also ensure that the object to be measured is not out of focus through special lighting and objective lens light collection angle design; and at the same time ensure the working distance of the large light collection angle lens.
[0064] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.
[0065] 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 foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and 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 triangulation device, characterized in that, The triangulation device includes: an illumination source, a detection objective lens group, and a detector; The illumination source is used to generate an illumination beam and incident on the surface of the object to be measured; The detection objective lens group includes a switchable first detection objective lens group and a second detection objective lens group, and the first detection objective lens group and the second detection objective lens group have different focal lengths; the detection objective lens group is used to receive the spot signal containing the height information of the object to be measured; The detector is used to analyze the spot signal.
2. The triangulation device according to claim 1, wherein The first detection objective lens group and the second detection objective lens group are switched according to objects to be measured of different sizes.
3. The triangulation device according to claim 1, wherein The triangulation device further includes: a lens barrel, and the lens barrel is arranged between the detection objective lens group and the detector.
4. The triangulation device according to claim 3, wherein The lens barrel, the detection objective lens group, and the illumination beam are set to be parfocal.
5. The triangulation device according to claim 1, characterized in that, The reflected light of the illumination beam reflected by the surface of the object to be measured irradiates on the focal plane of the detection objective lens group.
6. The triangulation device according to claim 5, characterized in that, The illumination beam is perpendicular to the detection objective lens group.
7. The triangulation device according to claim 1, characterized in that, The incident angle of the illumination beam is a first angle, and the included angle between the detection objective lens group and the surface of the object to be measured is a second angle; the sum of the first angle and the second angle is 90°.
8. The triangulation device according to claim 7, characterized in that, The light acceptance angle of the detection objective lens group is greater than or equal to the difference between the first angle and the second angle.
9. The triangulation device according to claim 1, characterized in that, The detection objective lens group further includes: an objective lens switcher, and the distance from the objective lens mounting port of the objective lens switcher to the focal plane of the detection objective lens group is fixed.
10. The triangulation device according to claim 7, wherein, The detector is used to determine the height of the object to be measured based on the spot interval of the spot signal imaged on the detector, the focal length of the lens barrel, the focal length of the detection objective lens group, and the second angle.