Single field of view vision system, calibration device and alignment recognition method

Abstract

The present application relates to a single-field vision system, a calibration device and an alignment recognition method. The single-field vision system comprises: a first reflective element, a first light source, a first beam splitter element, a second light source, a second beam splitter element, a third beam splitter element, a second reflective element and a camera. The single-field vision system of the present application can be applied to the high-precision alignment recognition process in the process flow of a solder printer. By using only one set of cameras and sacrificing the spacing between the first target and the second target to obtain a smaller lateral size, the system is simpler and the cost is reduced while maintaining high-precision alignment.

Description

Technical Field

[0001] The present application relates to the field of optical systems, and in particular to a single-field vision system, a calibration device, and an alignment and recognition method. Background Art

[0002] With the development of semiconductor technology, there has emerged a technology for positioning and aligning semiconductor devices or optoelectronic devices. Usually, in the process of semiconductor chip manufacturing and optoelectronic device manufacturing, machine vision systems are often used to achieve positioning and alignment of different devices.

[0003] However, as the feature size of semiconductor manufacturing processes becomes smaller and smaller and the precision requirements become higher and higher, various requirements have arisen for the visual system to achieve upper and lower device alignment. Traditional alignment systems face new challenges in device positioning accuracy, alignment accuracy, image quality and overall size. Summary of the invention

[0004] Based on this, it is necessary to provide a single-field vision system, a calibration device and an alignment recognition method that can improve the positioning accuracy, alignment accuracy, image quality of the device and reduce the overall size in order to address the above-mentioned technical problems.

[0005] In a first aspect, the present application provides a single-view visual system, comprising:

[0006] A first reflecting element having a first reflecting surface and a second reflecting surface disposed opposite to each other;

[0007] The first light source;

[0008] a first beam splitter element, opposite to the first light source and the first reflective surface, the first beam splitter element being capable of reflecting at least part of the light emitted by the first light source onto the first target object, and at least part of the light reflected by the first target object being capable of passing through the first beam splitter element and being emitted onto the first reflective surface;

[0009] a second light source, opposite to the second reflecting surface;

[0010] a second beam splitter element, opposite to the second reflective surface, the second reflective surface being capable of reflecting at least a portion of the light emitted by the second light source toward the second beam splitter element, so that the light can pass through the second beam splitter element and be emitted to the second target object;

[0011] a third beam splitting element, opposite to the first reflecting surface and used to receive at least a portion of the light reflected by the first reflecting surface;

[0012] a second reflecting element, opposite to the third beam splitting element and the second beam splitting element, the second beam splitting element being capable of reflecting at least a portion of the light reflected by the second target object onto the second reflecting element, and the second reflecting element being used to reflect the light from the second beam splitting element onto the third beam splitting element;

[0013] The camera is opposite to the third beam splitter element, and the third beam splitter element is used to combine the light from the first reflective surface and at least part of the light from the second reflective element and then emit the light to the camera.

[0014] In one embodiment, the first beam splitting element, the first reflecting element and the second beam splitting element are arranged in sequence in the first direction; the second light source, the first reflecting element, the third beam splitting element and the camera are arranged in sequence in the second direction, and the first direction and the second direction are perpendicular to each other.

[0015] In one embodiment, the second reflective element is disposed on a side of the third beam splitter element facing away from the first beam splitter element in the first direction; the first light source is disposed on a side of the first beam splitter element in the third direction, and the third direction is perpendicular to the first direction and the second direction.

[0016] In one embodiment, the angle between the surface of the first beam splitter element facing the first light source and the light emitting surface of the first light source is 45°, and the surface of the first beam splitter element facing the first light source is used to be inclined opposite to the first target object;

[0017] The light splitting surface of the third light splitting element is perpendicular to the first reflecting surface and parallel to the reflecting surface of the second reflecting element;

[0018] The second beam splitting element is perpendicular to the second reflecting surface and parallel to the reflecting surface of the second reflecting element.

[0019] In one embodiment, the first reflective element includes a first reflector and a second reflector, the first reflector and the second reflector are arranged opposite to each other, and the interval between the first reflector and the second reflector is less than 1 mm, and the first reflective surface and the second reflective surface are respectively arranged on two sides opposite to each other of the first reflector and the second reflector.

[0020] In one of the embodiments, the single-view visual system further includes a lens, the lens includes at least one lens with optical power, and the lens is arranged between the third beam splitting element and the camera along the second direction.

[0021] In one embodiment, the single field of view visual system further comprises:

[0022] A first annular light source is disposed on a side of the first beam splitter element facing the first target object, and a projection of the first annular light source on the first beam splitter element is disposed around the first beam splitter element;

[0023] The second annular light source is arranged on a side of the second beam splitter element facing the second target object, and the projection of the second annular light source on the second beam splitter element is arranged around the second beam splitter element.

[0024] In one embodiment, the single field of view vision system further comprises:

[0025] The first aperture is disposed between the first reflecting element and the first beam splitting element along the first direction; and the second aperture is disposed between the first reflecting element and the second beam splitting element along the first direction.

[0026] In the second aspect, the present application also provides a calibration device for calibrating a single-field vision system of any embodiment of the first aspect, the calibration device comprising an autocollimator and a shading member. When the calibration device calibrates the single-field vision system, the autocollimator is used to be placed at the camera, and the shading member is used to block between the third scattering element and the first reflecting element, or between the third scattering element and the second reflecting element.

[0027] In a third aspect, the present application further provides an alignment recognition method, which is applied to a single-view visual system as in any embodiment of the first aspect, and includes:

[0028] Moving the single-view vision system until a first feature of the first target object is located at an imaging center of a first light path formed by a first light source, a first beam splitter element, a first reflective element, and a third beam splitter element;

[0029] Move the second target object until the first feature of the second target object is located at the imaging center of the second light path formed by the second light source, the first reflecting element, the second beam splitting element, the second reflecting element and the third beam splitting element;

[0030] Moving the single-field vision system again until the second feature of the first target object is located at the imaging center of the first optical path;

[0031] The first translational degree of freedom, the second translational degree of freedom, and the rotational degree of freedom of the second target object are adjusted until the second feature of the second target object is located at the imaging center of the second optical path.

[0032] The above-mentioned single-field vision system, calibration device and alignment and recognition method, through a single-field vision system composed of a first reflecting element, a first light source, a first spectroscopic element, a second light source, a second spectroscopic element, a third spectroscopic element, a second reflecting element and a camera, can be applied to the high-precision alignment and recognition process in the process flow of a solder printer. By using only one set of cameras and sacrificing the distance between the first target object and the second target object to obtain a smaller lateral size, the system is simpler and the cost is reduced while maintaining high-precision alignment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] FIG1 is a schematic diagram of the structure of a single-view visual system in one embodiment;

[0035] FIG2 is a left side view of the single field of view vision system shown in FIG1 without the second light source in one embodiment;

[0036] FIG3 is a diagram of a calibration device for calibrating a single-view visual system in one embodiment;

[0037] FIG4 is an alignment identification method in one embodiment;

[0038] 5 to 7 are schematic diagrams of process flow diagrams corresponding to an alignment identification method in one embodiment;

[0039] FIG8 is a schematic diagram of a process of pressing a first target object to a second target object in one embodiment;

[0040] FIG9 is a schematic diagram of a process for obtaining a coaxiality deviation of a single-view visual system in one embodiment;

[0041] FIG. 10 is a schematic diagram of an algorithm for calculating coaxiality in one embodiment. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0043] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0044] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying 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 the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0045] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0047] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0048] The present invention can be applied to the high-precision alignment recognition process in the process flow of the solder printer. Before the solder printer performs printing, the first target object for filtering solder, such as a steel mesh, and the second target object, such as a PCB (Printed Circuit Board) board, are placed in an up-and-down layout and have small holes for positioning for high-precision alignment. The methods for achieving up-and-down alignment generally include non-coaxial alignment and coaxial alignment, which distinguish whether the upper and lower positioning holes are exactly opposite to each other during the final alignment. The coaxial alignment method is commonly used. There are two methods for achieving up-and-down coaxial alignment: (1) using two sets of imaging cameras and corresponding lens configurations. The two cameras and lenses are usually arranged symmetrically on the left and right. The upper and lower imaging beams enter the two cameras respectively, and the upper and lower coaxial alignment is achieved by comparing the imaging on both sides; (2) using only one set of imaging cameras and lenses. The upper and lower imaging beams enter the same camera through the splitting optical path composed of a reflecting prism and a splitting prism. In order to avoid interference during simultaneous imaging, there is a sequence of imaging of the upper and lower surfaces, and the center of the camera imaging surface is used as a common reference for alignment. The dual-camera alignment system occupies a small longitudinal space and has a large lateral size. It is more suitable for situations where the spacing between the upper and lower alignment surfaces is small. At the same time, the optical paths on both sides are separated and do not interfere with each other, and the imaging quality is good. The advantages of the single-camera alignment system are more obvious. The lateral size is small, which can reduce the size of the equipment in front, behind, left and right directions. Only a single camera and lens are used, which can save costs and reduce system complexity. The difficulty of assembly and debugging is also much lower than that of the dual-camera alignment system, reducing the eccentricity error caused by the imaging of two sets of cameras. However, there are the following three problems: (1) It is impossible to use a coaxial light source, otherwise part of the light from the coaxial light source will directly or indirectly enter the lens, resulting in a decrease in imaging contrast and poor alignment accuracy; (2) The reflector and beam splitter in the optical path will weaken the imaging beam, resulting in a significant reduction in the energy ultimately transmitted to the camera chip; (3) The system is large in size and occupies a large space, resulting in limited application. To this end, the present application proposes a single-view visual system, a calibration device, and an alignment recognition method for upper and lower coaxial alignment recognition to solve the above problems.

[0049] Referring to FIG. 1 , FIG. 1 shows a schematic diagram of a single-field vision system 100 in an embodiment of the present invention. The single-field vision system 100 provided in an embodiment of the present invention includes: a first reflecting element 4 having a first reflecting surface and a second reflecting surface arranged opposite to each other; a first light source 61; a first beam splitting element 7, opposite to the first light source 61 and the first reflecting surface, the first beam splitting element 7 being able to reflect at least part of the light emitted by the first light source 61 onto a first target object 10, and at least part of the light reflected by the first target object 10 being able to pass through the first beam splitting element 7 and project onto the first reflecting surface; a second light source 62, opposite to the second reflecting surface; a second beam splitting element 8, opposite to the second reflecting surface, the second reflecting surface being able to reflect at least part of the light emitted by the second light source The light is reflected toward the second beam splitter element 8 so that the light can pass through the second beam splitter element 8 and hit the second target 11; the third beam splitter element 3 is opposite to the first reflecting surface and is used to receive at least part of the light reflected by the first reflecting surface; the second reflecting element 9 is opposite to the third beam splitter element 3 and the second beam splitter element 8, the second beam splitter element 8 can reflect at least part of the light reflected by the second target 11 onto the second reflecting element 9, and the second reflecting element 9 is used to reflect the light from the second beam splitter element 8 onto the third beam splitter element 3; the camera 1 is opposite to the third beam splitter element 3, and the third beam splitter element 3 is used to combine the light from the first reflecting surface and at least part of the light from the second reflecting element 9 and hit the camera 1.

[0050] Exemplarily, the first light source 61 and the second light source 62 can be surface light sources. Please refer to Figures 1 and 2 at the same time. Figure 2 is a left view of the single-view visual system 100 shown in Figure 1 without the second light source. The thin lines in Figures 1 and 2 indicate the direction of the light. Among them, the light emitted by the first light source 61 is reflected by the first spectroscopic element 7 and incident on the surface of the first target 10, such as a steel mesh. At least part of the light reflected by the first target 10 can pass through the first spectroscopic element 7 and be incident on the first reflection surface of the first reflection element 4. After being reflected by the first reflection surface, it passes through the third spectroscopic element 3 and is incident on the camera 1, thereby forming an image in the sensor chip in the camera. The light emitted by the second light source 62 is reflected by the second reflecting surface of the first reflecting element 4 and then incident on the second beam splitting element 8. After passing through the second beam splitting element 8, it is incident on the identification surface of the second target object 11, such as a PCB board. The light reflected by the second target object 11 is incident on the second beam splitting element 8 and then reflected by the second beam splitting element 8 to the second reflecting element 9. After being reflected by the second reflecting element 9, it is incident on the third beam splitting element 3 and reflected by the third beam splitting element 3, thereby being incident on the camera 1. The light reflected by the second target object 11 by the third beam splitting element 3 is incident on the camera 1 together with the photosynthetic light reflected by the first target object 10 passing through the third beam splitting element 3 in the third beam splitting element 3.

[0051] The above-mentioned single-field vision system 100 is a coaxial alignment device, which is composed of a first reflecting element 4, a first light source 61, a first beam splitting element 7, a second light source 62, a second beam splitting element 8, a third beam splitting element 3, a second reflecting element 9 and a camera 1. The single-field vision system 100 can be used in the high-precision alignment and recognition process in the process flow of a solder printer. By using a set of cameras and sacrificing the distance between the first target object and the second target object to obtain a smaller lateral size, the system is simpler and the cost is reduced while maintaining high-precision alignment.

[0052] In an exemplary embodiment, please continue to refer to Figures 1 and 2, the first spectroscopic element 7, the first reflecting element 4 and the second spectroscopic element 8 are arranged in sequence in the first direction D1; the second light source 62, the first reflecting element 4, the third spectroscopic element 3 and the camera are arranged in sequence in the second direction D2, and the first direction and the second direction are perpendicular to each other.

[0053] In an exemplary embodiment, the second reflecting element 9 is disposed on a side of the third beam splitting element 3 facing away from the first beam splitting element 7 in the first direction D1; the first light source 61 is disposed on a side of the first beam splitting element 7 in the third direction, and the third direction D3 is perpendicular to the first direction D1 and the second direction D2.

[0054] Optionally, the second reflecting element 9 is a right-angle reflecting prism, and in some embodiments, the right-angle reflecting prism includes an incident surface, a reflecting surface, and an exiting surface. The light reflected by the second target object 11 is reflected by the second beam splitting element 8, and then incident on the reflecting surface of the right-angle reflecting prism through the incident surface of the right-angle reflecting prism, and then incident on the third beam splitting element 3 after being reflected by the reflecting surface of the right-angle reflecting prism and exiting through the exiting surface of the right-angle reflecting prism.

[0055] In an exemplary embodiment, the angle between the surface of the first beam splitting element 7 facing the first light source 61 and the light emitting surface of the first light source 61 is 45°, and the surface of the first beam splitting element 7 facing the first light source 61 is used to be obliquely opposite to the first target object 10; the beam splitting surface of the third beam splitting element 3 is perpendicular to the first reflecting surface and parallel to the reflecting surface of the second reflecting element 9; the second beam splitting element 8 is perpendicular to the second reflecting surface and parallel to the reflecting surface of the second reflecting element 9.

[0056] Exemplarily, the first beam splitter element 7 and the second beam splitter element 8 each have two opposite beam splitter surfaces, which can be parallel to each other, wherein one beam splitter surface of the first beam splitter element 7 is opposite to the first light source 61 and the first target 10, and the other beam splitter surface is opposite to the first reflective element 4, so that it can play a role in reflecting and / or transmitting the incident light. In some embodiments, the angle between one beam splitter surface of the first beam splitter element 7 and the first light source 61 and the first target 10 is 45°, so that the angle between the reflected light and the transmitted light is 90°, and the mutual interference is small. One beam splitter surface of the second beam splitter element 8 is opposite to the incident surface of the second target 11 and the second reflective element 9, so that it can play a role in reflecting and / or transmitting the incident light. Specifically, the angle between one beam splitter surface of the second beam splitter element 7 and the incident surface of the second target 11 and the second reflective element 9 is 45°, so that the angle between the reflected light and the transmitted light is 90°, and the mutual interference is small.

[0057] In an exemplary embodiment, the first reflective element 4 includes a first reflector 41 and a second reflector 42, the first reflector 41 and the second reflector 42 are arranged opposite to each other, and the interval between the first reflector and the second reflector is less than 1 mm, and the first reflective surface and the second reflective surface are respectively arranged on opposite sides of the first reflector 41 and the second reflector 42.

[0058] In this embodiment, by making the distance between the first reflector 41 and the second reflector 42 of the first reflective element 4 within 1 mm, they can even fit together; and optionally, the first reflective element can be a two-sided reflector, thereby saving space in the single-field vision system 100 to the greatest extent.

[0059] In an exemplary embodiment, the single-view visual system 100 further includes a lens, the lens 2 includes at least one lens with optical power, and the lens 2 is disposed between the third beam splitting element 3 and the camera 1 along the second direction D2.

[0060] The above-mentioned single-field vision system 100, which is composed of a first reflecting element 4, a first light source 61, a first spectroscopic element 7, a second light source 62, a second spectroscopic element 8, a third spectroscopic element 3, a second reflecting element 9, a lens 2 and a camera 1, can be applied to the high-precision alignment and recognition process in the process flow of a solder printing machine. By using a set of cameras and lenses and sacrificing the spacing between the first target object 10 and the second target object 11 to obtain a smaller lateral size, the system is simpler and the cost is reduced while maintaining high-precision alignment.

[0061] In an exemplary embodiment, the single-field vision system 100 also includes a first annular light source 51, which is arranged on the side of the first beam splitter element 7 facing the first target object 10, and the projection of the first annular light source 51 on the first beam splitter element 7 is arranged around the first beam splitter element 7; a second annular light source 52, which is arranged on the side of the second beam splitter element 8 facing the second target object 11, and the projection of the second annular light source on the second beam splitter element 8 is arranged around the second beam splitter element 8.

[0062] It can be seen from the light propagation path that whether it is the reflected light obtained by irradiating the first target 10 or the reflected light obtained by irradiating the second target 11, it has undergone three splittings before entering the camera 1, and the light energy is greatly reduced. Therefore, in one embodiment, the single-view visual system 100 is equipped with an annular light source such as a first annular light source 51 and a second annular light source 52 at the light outlet facing the first target 10 and the second target 11 as an auxiliary light source to enhance the imaging light beam. Moreover, the light emitted by the annular light source is projected onto the object surface at a certain angle, and the coaxial light source emitted by the surface light source such as the first light source 61 and the second light source 62 can meet specific lighting requirements, while illuminating the target object and keeping the background dark. For example, high-angle light plus coaxial light can obtain an image in which only the electrode is bright, and low-angle light plus coaxial light can obtain an image in which both the electrode and the solder are bright. Among them, the electrode and the solder are both arranged on the second target 11, that is, the PCB board, but the reflectivity of the solder is low, while the reflectivity of the electrode is relatively high. That is to say, when the ring-shaped lamp beads of the first ring-shaped light source 51 and the second ring-shaped light source 52 are turned on at a low angle, diffuse reflection will occupy the main reflection, and the light reflected by the electrode and the solder will be received by the sensor of the camera 1; and when the ring-shaped lamp beads are turned on at a high angle, the angle between the lamp beads and the optical axis is close to zero or the angle is small, and the light close to the ring-shaped lamp beads is vertically incident, so the light reflected by the motor with higher reflectivity will be more received by the sensor of the camera 1.

[0063] In the present embodiment, by simultaneously providing a coaxial surface light source for realizing bright field illumination and an annular light source for realizing dark field illumination, the lighting methods include not only bright field illumination but also dark field illumination, thereby being able to meet application scenarios requiring dark field illumination, and making the single-field vision system 100 of the present embodiment have a wider application; and, since the single-field vision system 100 realizes imaging of the upper and lower surfaces through a split light path, the light energy transmitted from the object surface, such as the first target object 10 and the second target object 11, will be greatly reduced, and the external first annular light source and the second annular light source can also serve as auxiliary light sources to supplement part of the light energy.

[0064] In an exemplary embodiment, the single-field vision system 100 further includes: a first aperture, disposed between the first reflecting element 4 and the first beam splitting element 7 along the first direction; and a second aperture, disposed between the first reflecting element 4 and the second beam splitting element 8 along the first direction.

[0065] Since the first light source 61 and the second light source 62 are directed toward the inside of the single-field vision system 100, a field aperture should be added between each optical element of the single-field vision system 100 according to actual needs to prevent the light from the surface light source from directly or indirectly entering the lens or camera without hitting the object surface, thereby eliminating stray light. Optionally, a first aperture is set between the first reflecting element 4 and the first beam splitting element 7 along the first direction D1, and a second aperture is set between the first reflecting element 4 and the second beam splitting element 8 along the first direction D1, thereby preventing stray light from entering the lens 2. Optionally, apertures are set at the light outlets of the first light source 61 and the second light source 62 to limit the light output, for example, a third aperture is set between the first light source 61 and the first beam splitting element 7 along the third direction D3; a fourth aperture is set between the second light source 62 and the first reflecting element 4 along the second direction D2.

[0066] In one embodiment, please refer to FIG. 1 and FIG. 2 , the single-view visual system 100 mainly includes a camera 1, a lens 2, a third beam splitter 3, a first reflective element 4, a first annular light source 51, a second annular light source 52, a first light source 61, a second light source 62, a first beam splitter 7, a second beam splitter 8, and a second reflective element 9. Among them, the first target 10, such as a steel mesh, and the second target 11, such as a PCB board, are processed with alignment holes for positioning; the first annular light source 51 and the second annular light source can be RGBW light sources, which combine RGB (red, green, blue) three primary colors and W (white) four-color light source; the first light source 61 and the second light source 62 can be surface light sources; the lens 2 can be a telecentric lens; the third beam splitter 3 can be a beam splitter prism; the first reflective element 4 can be a plane reflector; the first beam splitter 7 and the second beam splitter 8 can be beam splitters; the second reflective element 9 can be a right-angle reflective prism.

[0067] The arrows in FIG. 1 and FIG. 2 indicate the direction of light. Among them, in the second optical path composed of the second light source 62, the first reflective element 4, the second beam splitter element 8, the second reflective element 9 and the third beam splitter element 3, the uniform light emitted by the first light source 61 is reflected by the first reflective element 4 and hits the second target 11, i.e., the recognition surface of the PCB board. The reflected imaging light beam is reflected by the second beam splitter element 8, the second reflective element 9 and the third beam splitter element 3 and enters the lens 2, and finally forms an image on the chip of the camera 1. In the first optical path composed of the first light source 61, the first beam splitter element 7, the first reflective element 4 and the third beam splitter element 3, the light emitted by the first light source 61 is reflected by the first beam splitter element 7 and hits the surface of the first target 10, such as a steel mesh. The reflected imaging light beam enters the lens 2 through the first reflective element 4 and the third beam splitter element 3 and finally forms an image on the chip of the camera 1. In order to save space to the greatest extent, the spacing between the optical elements in the layout is relatively small. The first reflective element 4 used in the first optical path and the second optical path can be composed of two plane reflectors, such as the first reflector 41 and the second reflector 42, wherein the distance between the first reflector 41 and the second reflector 42 is within 1 mm, and can even be fitted together, or replaced by two reflectors. Since the first light source 61 and the second light source 62 are facing the inside of the single-view visual system 100, a field of view aperture should be added between each optical element according to actual needs to prevent the surface light source from directly or indirectly entering the lens without hitting the object surface, thereby eliminating stray light. The light outlets of the first light source 61 and the second light source 62 should have apertures to limit the light outlet, and an aperture needs to be added between the first reflective element 4 and the first beam splitting element 7 and the second beam splitting element 8 to prevent stray light from entering the lens 2. It can be seen from the light propagation path that the imaging light beams of the first optical path and the second optical path have undergone three beam splittings, and the light energy is greatly reduced. Therefore, the single-view visual system 100 is equipped with annular light sources, such as the first annular light source 51 and the second annular light source 52, as auxiliary light sources to enhance the imaging light beam. Moreover, the light emitted by the ring light source is at a certain angle when it hits the object surface. When combined with the coaxial light source emitted by the surface light source, it can meet specific lighting requirements, illuminating the target object while keeping the background dark. For example, high-angle light plus coaxial light can obtain an image in which only the electrode is bright, while low-angle light plus coaxial light can obtain an image in which both the electrode and the solder are bright.

[0068] Please refer to Figure 3, which shows a calibration device in an embodiment of the present application for calibrating the single-field vision system 100 in any of the aforementioned embodiments. The calibration device includes an autocollimator 12 and a shading member. When the calibration device calibrates the single-field vision system 100, the autocollimator 12 is used to be placed at the camera 1, and the shading member is used to block between the third scattering element 3 and the first reflecting element 4, or block between the third scattering element 3 and the second reflecting element 9.

[0069] Exemplarily, as shown in FIG3 , the lens 2 and the camera 1 are first removed, and the autocollimator 12 is installed at the interface of the lens 2 on the device through the tooling, and plane reflectors are installed at the positions of the upper and lower light outlets, for example, the third reflector 13 is placed at the position of the first target 10 in FIG1 , and the fourth reflector 14 is placed at the position of the second target 11. The third reflector 13 and the fourth reflector 14 are used to reflect the laser emitted by the autocollimator 12 back, and the autocollimator 12 will form a crosshair image after receiving the laser. When all optical elements in the optical path are in an ideal posture and position, the crosshair image will be close to the position of the emitted laser. The scheme for calibrating the optical path in FIG3 is: first, place a light shielding member such as a black cloth between the third light splitting element 3 and the second reflecting element 9 for shielding, then adjust the third light splitting element 3 and the first reflecting element 4 until the distance from the brightest crosshair image in the software interface, such as the software used to match the autocollimator 12, to the center of the interface is within one line, then remove the light shielding member and place it between the third light splitting element 3 and the first reflecting element 4, and finally adjust the second reflecting element 9 until the distance from the brightest crosshair image in the software interface to the center of the interface is within the required distance. At this point, the first optical path and the second optical path have been calibrated.

[0070] In this embodiment, the mirror bases of the third light splitting element 3, the first reflecting element 4, and the second reflecting element 9 can be designed to be adjustable, and the axis of the optical path is adjusted to an ideal state through the calibration device to obtain an ideal imaging quality close to the design target. Using the calibration device of this embodiment to calibrate the single-view visual system 100 can provide higher mechanical accuracy for the imaging of the single-view visual system 100, and effectively reduce the processing accuracy and cost of the housing and the mirror base of the single-view visual system 100.

[0071] Based on the same inventive concept, an embodiment of the present application also provides an alignment and recognition method for a single-field vision system 100 applied to any of the aforementioned embodiments. Please refer to Figures 4 to 7. Figure 4 is an alignment and recognition method of an embodiment of the present application, comprising the following steps: S402 to S408; Figures 5 to 7 are schematic diagrams of the process flow corresponding to the alignment and recognition method in an embodiment of the present application.

[0072] S402 : Move the single-field vision system 100 until the first feature 15 of the steel mesh of the first target object 10 is located at the imaging center of the first light path formed by the first light source 61 , the first beam splitter element 7 , the first reflective element 4 and the third beam splitter element 3 .

[0073] Please refer to FIG. 5 at the same time. For example, the first feature 15 of the steel mesh of the first target 10 can be a positioning hole on the steel mesh. Move the single-view vision system 100 until the first feature 15 of the steel mesh, i.e., the positioning hole, on the steel mesh is located at the imaging center of the first optical path of the single-view vision system 100, wherein the first optical path includes the first light source 61, the first beam splitter element 7, the first reflective element 4, and the third beam splitter element 3. For example, the arrow in FIG. 5 indicates the moving direction of the single-view vision system 100.

[0074] S404 : moving the second target object 11 until the first feature 17 of the PCB board of the second target object 11 is located at the imaging center of the second light path formed by the second light source 62 , the first reflecting element 4 , the second beam splitting element 8 , the second reflecting element 9 and the third beam splitting element 3 .

[0075] Please refer to Figures 5 and 6 at the same time. For example, the first feature 17 of the PCB board of the second target object 11 can be a positioning hole on the PCB board. After the first feature 15 of the steel mesh of the first target object 10 is located at the imaging center of the first optical path, the second target object 11 is moved until the first feature 17 of the PCB board of the second target object 11 is located at the imaging center of the second optical path. The second optical path includes a second light source 62, a first reflecting element 4, a second beam splitting element 8, a second reflecting element 9 and a third beam splitting element 3. For example, the arrow in Figure 6 indicates the moving direction of the second target object 11.

[0076] S406: Move the single-view vision system 100 again until the second feature 16 of the steel mesh of the first target object 10 is located at the imaging center of the first optical path.

[0077] Please refer to FIG. 5 and FIG. 7 simultaneously. For example, the second feature 16 of the steel mesh of the first target object 10 can be a positioning hole on the steel mesh. At this time, the single-view visual system 100 is moved again until the second feature 16 of the steel mesh of the first target object 10 is located at the imaging center of the first optical path. For example, the arrow in FIG. 7 indicates the moving direction of the single-view visual system 100.

[0078] S408: Adjust the first translational degree of freedom, the second translational degree of freedom, and the rotational degree of freedom of the second target object 11 until the second feature 18 of the PCB board of the second target object 11 is located at the imaging center of the second optical path.

[0079] At this time, by adjusting the three degrees of freedom of the second target object 11, i.e., the PCB board, the second feature 18 of the PCB board and the second feature 16 of the steel mesh are aligned, thereby completing the vertical alignment of the steel mesh and the PCB board.

[0080] In this embodiment, by using the single-field vision system of any of the foregoing embodiments of the present application, high-precision alignment of the first target object and the second target object can be achieved.

[0081] In an exemplary embodiment, as shown in Fig. 8, the alignment and recognition method further includes the step of pressing the first target object to the second target object. Exemplarily, after removing the single-view visual system, the first target object, i.e., the steel mesh, is pressed down, and the solder is filtered through the steel mesh and falls onto the second target object, i.e., the PCB board, and the scraper scrapes off the excess solder.

[0082] In an exemplary embodiment, the alignment identification method further includes the step of calibrating the single-view vision system using a calibration device.

[0083] In an exemplary embodiment, the alignment identification method also includes obtaining the coaxiality deviation of the single-field vision system. When the coaxiality deviation exceeds a threshold, the first reflective element 4 is adjusted to adjust the imaging center of the first optical path; when the coaxiality deviation does not exceed the threshold, compensation is performed through an algorithm.

[0084] Among them, obtaining the coaxiality deviation of the single-field vision system includes: setting the single-field vision system between the first marking plate 19 and the second marking plate 20; the first marking plate 19 and the second marking plate 20 are set on the same rotating table 23 and have the same rotation center; turning on the first surface light source 61 of the first optical path to obtain the first marking image of the first marking plate; the first marking image has a first marking point; turning off the first surface light source 61 of the first optical path, turning on the second surface light source 62 of the second optical path, obtaining the second marking image of the second marking plate; the second marking image has a second marking point; rotating the rotating table by a fixed angle multiple times, synchronously obtaining the first marking image and the second marking image each time; until a predetermined number of first marking images and second marking images are obtained; obtaining the first rotation center 21 of the first marking point, and obtaining the second rotation center 22 of the second marking point; extracting the distance between the first rotation center 21 and the second rotation center 22 through a comparison algorithm to obtain the coaxiality deviation.

[0085] For example, please refer to Figure 9 and Figure 10 simultaneously. Figure 9 is a schematic diagram of the process of obtaining the coaxiality deviation of the single-view visual system; Figure 10 is a schematic diagram of the algorithm for calculating the coaxiality.

[0086] Among them, the upper and lower cross mark plates, namely the first mark plate 19 and the second mark plate 20, are first connected by a rotating table 23 which is also a bracket, and then the bracket is connected to a high-precision manual rotating table, so that the two cross mark plates have the same rotation center. The assembled single-view visual system 100 is fixed between the two cross mark plates. At this time, there should be a crosshair image in the first optical path and the second optical path imaging. After the rotating table 23 is rotated by hand to a fixed angle, the first light source 61 of the first optical path is turned on, and the camera 1 is used to take a photo containing the upper crosshair image, namely the first mark image, and then the first light source 61 of the first optical path is turned off, and the second light source 62 of the second optical path is turned on, and the camera 1 is used to take a photo containing the lower crosshair image, namely the second mark image. Repeat this process until a sufficient number of first mark images and second mark images are obtained. As shown in the algorithm principle diagram of calculating coaxiality in Figure 10, the image processing algorithm first stacks the crosshair images in the first mark image and the second mark image, namely the first mark point and the second mark point, and extracts the rotation center of the two crosshair images, namely the first rotation center 21 and the second rotation center 22 through these crosshair images. Theoretically, the rotation centers of the two crosshairs should be at the same position, and the coaxiality deviation can be obtained by comparing the two rotation centers extracted by the algorithm. If the coaxial deviation is within the required accuracy range, the algorithm can be compensated. If the coaxial deviation is too large, the center position of the upper optical path imaging can be adjusted by adjusting the first reflective element 4, thereby reducing the coaxial deviation of the first optical path imaging and the second optical path imaging.

[0087] In one embodiment, after completing the calibration of the first optical path and the second optical path and reducing the coaxial deviation of the imaging of the first optical path and the second optical path, the first target 10 and the second target 11 are aligned through the single-field vision system 100. The first target 10, such as a steel mesh, is fixed, while the second target 11, such as a PCB board, can be displaced in the X and Y directions and rotated around the Z axis. The single-field vision system 100 only needs to perform displacements in the X, Y, and Z directions. The alignment and identification method of the single-field vision system 100 includes: moving the single-field vision system 100, finding the first feature 15 of the steel mesh processed on the steel mesh, allowing the first feature to appear in the center of the first optical path imaging, and then moving the PCB board so that the PCB board first feature 17 of the PCB board also appears in the center of the first optical path imaging. At this time, the first feature 15 of the steel mesh and the first feature 17 of the PCB board of the PCB board are aligned. Then, the single-view vision system 100 is moved to find the second feature 16 of the steel mesh, and the second feature 18 of the PCB board and the second feature 16 of the steel mesh are aligned by adjusting the three degrees of freedom of the PCB board, thereby completing the vertical alignment of the steel mesh and the PCB board. Finally, the single-view vision system 100 is removed, the steel mesh is pressed down, and the solder is filtered through the steel mesh and falls onto the PCB board, and then the excess solder is scraped off with a scraper.

[0088] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0089] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0090] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present application. It should be noted that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A single-view visual system, characterized in that: include: A first reflecting element (4) having a first reflecting surface and a second reflecting surface arranged opposite to each other; a first light source (61); a first beam splitter element (7), opposite to the first light source (61) and the first reflective surface, the first beam splitter element (7) being capable of reflecting at least part of the light emitted by the first light source (61) onto a first target object (10), and at least part of the light reflected by the first target object (10) being capable of passing through the first beam splitter element (7) and being emitted onto the first reflective surface; a second light source (62), opposite to the second reflecting surface; a second beam splitter element (8), opposite to the second reflective surface, the second reflective surface being capable of reflecting at least part of the light emitted by the second light source toward the second beam splitter element (8), so that the light can pass through the second beam splitter element (8) and be emitted to a second target object (11); A third beam splitting element (3), opposite to the first reflecting surface, and used for receiving at least part of the light reflected by the first reflecting surface; a second reflecting element (9), opposite to the third beam splitting element (3) and the second beam splitting element (8), the second beam splitting element (8) being capable of reflecting at least part of the light reflected by the second target object (11) onto the second reflecting element (9), and the second reflecting element (9) being used to reflect the light from the second beam splitting element (8) onto the third beam splitting element (3); The camera (1) is opposite to the third beam splitting element (3), and the third beam splitting element (3) is used to combine at least part of the light from the first reflecting surface and from the second reflecting element (9) and emit the combined light to the camera (1).

2. The single-view visual system according to claim 1, characterized in that: The first beam splitting element (7), the first reflecting element (4) and the second beam splitting element (8) are arranged in sequence and at intervals in a first direction; the second light source (62), the first reflecting element (4), the third beam splitting element (3) and the camera are arranged in sequence and at intervals in a second direction, and the first direction and the second direction are perpendicular to each other.

3. The single-view visual system according to claim 2, characterized in that: The second reflecting element (9) is arranged on a side of the third beam splitting element (3) facing away from the first beam splitting element (7) in the first direction; The first light source (61) is arranged on one side of the first light splitting element (7) in a third direction, and the third direction is perpendicular to the first direction and the second direction.

4. The single-view visual system according to claim 1, characterized in that: The included angle between the surface of the first beam splitting element (7) facing the first light source (61) and the light emitting surface of the first light source (61) is 45°, and the surface of the first beam splitting element (7) facing the first light source (61) is used to be inclined opposite to the first target object (10); The light splitting surface of the third light splitting element (3) is perpendicular to the first reflecting surface and parallel to the reflecting surface of the second reflecting element (9); The second beam splitting element (8) is perpendicular to the second reflecting surface and parallel to the reflecting surface of the second reflecting element (9).

5. The single-view visual system according to claim 1, characterized in that: The first reflecting element (4) comprises a first reflecting mirror (41) and a second reflecting mirror (42), the first reflecting mirror (41) and the second reflecting mirror (42) being arranged opposite to each other, and the interval between the first reflecting mirror and the second reflecting mirror is less than 1 mm, and the first reflecting surface and the second reflecting surface are respectively arranged on opposite sides of the first reflecting mirror (41) and the second reflecting mirror (42).

6. The single-view visual system according to claim 2, characterized in that: It also comprises a lens (2), the lens (2) comprising at least one lens having optical focal length, and the lens (2) being arranged between the third beam splitting element (3) and the camera (1) along the second direction.

7. The single-view visual system according to claim 1, characterized in that: Also includes: A first annular light source (51) is arranged on a side of the first light splitting element (7) facing the first target object (10), the projection of the first annular light source (51) on the first light splitting element (7) being arranged around the first light splitting element (7); A second annular light source (52) is arranged on a side of the second light splitting element (8) facing the second target object (11), and a projection of the second annular light source on the second light splitting element (8) is arranged around the second light splitting element (8).

8. The single-view visual system according to claim 2, characterized in that: Also includes: A first aperture, arranged along the first direction between the first reflecting element (4) and the first light splitting element (7); as well as A second aperture is arranged along the first direction between the first reflecting element (4) and the second light splitting element (8).

9. A calibration device for calibrating the single-view visual system according to any one of claims 1 to 8, characterized in that: The calibration device comprises an autocollimator and a shading member. When the calibration device calibrates the single-field vision system, the autocollimator (12) is used to be placed at the camera (1), and the shading member is used to block between the third beam splitting element (3) and the first reflecting element (4), or between the third beam splitting element (3) and the second reflecting element (9).

10. An alignment recognition method, characterized in that: The method is applied in a single-view visual system as claimed in any one of claims 1 to 8, comprising: Moving the single-field vision system until the first feature (15) of the steel mesh of the first target object is located at the imaging center of the first light path formed by the first light source (61), the first beam splitter element (7), the first reflective element (4) and the third beam splitter element (3); Moving the second target object (11) until the first feature (17) of the PCB board of the second target object is located at the imaging center of the second light path formed by the second light source (62), the first reflecting element (4), the second beam splitting element (8), the second reflecting element (9) and the third beam splitting element (3); Moving the single-view vision system again until the second feature (16) of the steel mesh of the first target object is located at the imaging center of the first optical path; The first translational degree of freedom, the second translational degree of freedom and the rotational degree of freedom of the second target object are adjusted until a second feature (18) of the PCB board of the second target object is located at an imaging center of the second optical path.

Images