Optical detection system and optical detection equipment

Abstract

The invention relates to the technical field of optical detection, in particular to an optical detection system and optical detection equipment. A first optical element for changing a bright field illumination light beam into first linearly polarized light is arranged in a light path of the bright field illumination light beam; a second optical element for changing the dark field illumination light beam into second linearly polarized light is arranged in a light path of the dark field illumination light beam, the polarization direction of the first linearly polarized light is different from that of the second linearly polarized light, and the first optical element is used for inhibiting the first stray light from being mixed into a transmission path of the first linearly polarized light; the first stray light comprises light which reaches the bright field illumination lens group after the second linearly polarized light is reflected and / or scattered; therefore, in the dark field detection process, the first stray light is prevented from being reflected by the bright field illumination lens group through the first optical element, the adverse effect of the first stray light on dark field imaging is reduced, the imaging quality and the imaging effect of dark field images are improved, and the detection efficiency and the detection accuracy are improved.

Description

Technical Field

[0001] The present application relates to the field of optical detection technology, and in particular to an optical detection system and an optical detection device. Background Art

[0002] Wafer defect detection is a very important link in the field of semiconductor manufacturing technology. Among them, optical line scan imaging technology is a common surface defect detection technology in the field of semiconductor detection. By using optical components such as cameras, light sources, lenses and other components, it can effectively detect defects such as dust, dirt, particles, scratches, and broken wires on the wafer surface. Existing macro line scan product surface defect detection technologies mainly include bright field defect detection and dark field defect detection. There may be reflections between the lenses of bright field light sources and dark field light sources. This reflection will cause the wafer to be imaged in the camera more than once, causing the wafer to be imaged multiple times, which will seriously affect the accuracy of wafer defect detection and affect the overall detection performance of the system.

[0003] For example, during dark-field defect detection, the scattered light of the dark-field illumination beam will be reflected by the lens of the bright-field light source to form stray light. The stray light will be transmitted along the imaging optical path and captured by the camera to cause multiple images. Since the camera is very sensitive to incoming light under dark-field imaging conditions, a small amount of stray light will also seriously affect the dark-field imaging quality, thereby reducing the accuracy of defect detection. Summary of the invention

[0004] The present application provides an optical detection system and an optical detection device to overcome the adverse effects of light beam reflection on imaging quality in bright and dark field detection.

[0005] According to the first aspect, an optical detection system is provided in one embodiment, comprising: A bright field light source, used for generating a bright field illumination beam; A dark field light source, used for generating a dark field illumination beam; A bright field illumination lens assembly is arranged on the optical path of the bright field illumination light beam, and the bright field illumination lens assembly comprises a first optical element, and the first optical element is used to change the bright field illumination light beam into a first linearly polarized light; A dark field illumination mirror group, arranged on the optical path of the dark field illumination light beam, the dark field illumination mirror group comprising a second optical element, the second optical element being used to change the dark field illumination light beam into a second linearly polarized light; the polarization direction of the first linearly polarized light is different from the polarization direction of the second linearly polarized light; the first optical element is also used to suppress first stray light from being mixed into the transmission path of the first linearly polarized light, the first stray light comprising the light of the second linearly polarized light reaching the bright field illumination mirror group after being reflected and / or scattered; An image acquisition device is used to acquire a first signal light generated by the reflection of the first linear polarized light on the surface of the product under test, and obtain a bright field image of the product under test, or to acquire a second signal light generated by the scattering of the second linear polarized light on the surface of the product under test, and obtain a dark field image of the product under test.

[0006] In an optional embodiment, there is an orthogonal relationship between the polarization direction of the first linear polarized light and the polarization direction of the second linear polarized light.

[0007] In an optional embodiment, the first optical element is located on the light exit side of the bright field illumination lens group in the optical path of the bright field illumination light beam; and / or the second optical element is located on the light exit side of the dark field illumination lens group in the optical path of the dark field illumination light beam.

[0008] In an optional embodiment, the first linearly polarized light emitted by the bright field illumination lens group forms a first angle with the surface of the product to be measured, and the range of the first angle is 60°±25°; and / or, The second linearly polarized light emitted by the dark field illumination lens group forms a second angle with the surface of the product to be measured, and the range of the second angle is 45°±25°.

[0009] In an optional embodiment, the second optical element is further used to suppress second stray light from mixing into the transmission path of the second linearly polarized light, where the second stray light includes light from the first linearly polarized light that reaches the dark field illumination mirror assembly after being reflected and / or scattered.

[0010] In an optional embodiment, the first optical element and the second optical element are both polarizers or Nicol prisms.

[0011] In an optional embodiment, the number of the dark field light source and the dark field illumination mirror group are both multiple, and the multiple dark field illumination mirror groups correspond one to one to the multiple dark field light sources; the optical axes of two of the multiple dark field illumination mirror groups are arranged symmetrically about the normal of the product to be measured.

[0012] In an optional embodiment, the optical detection system includes a first adjustment component, and the first adjustment component is used to adjust the pitch angle and / or position of the bright field illumination lens group; and / or, The optical detection system comprises a second adjustment component, and the second adjustment component is used to adjust the pitch angle and / or position of the dark field illumination lens group.

[0013] In an optional embodiment, the optical detection system includes a third adjustment component, and the third adjustment component is used to adjust the pitch angle and / or position of the image acquisition device.

[0014] According to the second aspect, an optical inspection device is provided in an embodiment, comprising a carrying device and the optical inspection system described in any one of the above items, wherein the carrying device is used to carry and limit the product to be tested, and drive the product to be tested to move, and the optical inspection system performs optical inspection on the product to be tested on the carrying device.

[0015] In an optional embodiment, the optical inspection device has a bright field inspection mode and a dark field inspection mode; in the bright field inspection mode, the bright field light source generates a bright field illumination beam, and the image acquisition device obtains a bright field image of the product under inspection; in the dark field inspection mode, the dark field light source generates a dark field illumination beam, and the image acquisition device obtains a dark field image of the product under inspection.

[0016] In an optional embodiment, a driving mechanism is further included, wherein the driving mechanism is connected to the carrying device and spatially isolated from the optical detection system, and the driving mechanism is used to drive the carrying device to perform linear movement relative to the optical detection system.

[0017] According to the optical inspection system and the optical inspection device of the above-mentioned embodiment, since a first optical element for changing the bright field illumination beam into a first linear polarized light is arranged in the optical path of the bright field illumination beam, and a second optical element for changing the dark field illumination beam into a second linear polarized light is arranged in the optical path of the dark field illumination beam, the polarization direction of the first linear polarized light is different from the polarization direction of the second linear polarized light, and the first optical element is used to suppress the first stray light from mixing into the transmission path of the first linear polarized light, and the first stray light includes the light of the second linear polarized light reaching the bright field illumination mirror group after being reflected and / or scattered; in this way, during the dark field inspection process, the first stray light generated by the second linear polarized light after being reflected and / or scattered by the product to be inspected can be suppressed by the first optical element from being reflected by the bright field illumination mirror group, thereby suppressing the first stray light reflected by the bright field illumination mirror group from being transmitted on the transmission path of the first linear polarized light to form an interference image in the image acquisition device, and thus reducing the adverse effect of the first stray light generated by the second linear polarized light on the dark field imaging quality, which helps to improve the imaging quality and imaging effect of the dark field image, facilitates the detection and identification of different types of defects in dark field inspection, and improves the detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the bright field detection optical path in the optical detection system of the prior art; Figure 2 It is a schematic diagram of the dark field detection optical path structure in the prior art optical detection system; Figure 3 A schematic diagram of a dark field detection optical path structure in an optical detection device according to an embodiment; Figure 4The figure is a schematic diagram of the bright field detection light path structure in an optical detection device according to an embodiment.

[0019] Figure 1 and Figure 2 In the figure: 100, bright field light source; 110, bright field illumination lens group; 200, dark field light source; 210, dark field illumination lens group; 300, image acquisition device; 400, first detection light; 410, first signal light; 430, second stray light; 500, second detection light; 510, second signal light; 530, first stray light.

[0020] Figure 3 and Figure 4 In: 10, bright field light source; 11, bright field illumination lens group; 111, first optical element; 12, first adjustment component; 20, dark field light source; 21, dark field illumination lens group; 211, second optical element; 22, second adjustment component; 3, image acquisition device; 31, camera; 32, lens; 30, third adjustment component; 40, first linear polarized light; 41, first signal light; 43, second stray light; 50, second linear polarized light; 51, second signal light; 53, first stray light; 6, carrying device; 61, adsorption component; 62, carrying platform; 8, driving mechanism.

[0021] Explanation on the reference numerals in brackets in the drawings: In the reference numerals in brackets in the drawings, the features referred to by the reference numerals are both the features represented by the numbers in the brackets and the features represented by the numbers outside the brackets. DETAILED DESCRIPTION

[0022] The present application is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are intended to enable the present application to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, and methods. In some cases, some operations related to the present application are not shown or described in the specification, in order to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0023] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations, and the operation steps involved in each embodiment can also be replaced or adjusted in a sequence in a manner that is obvious to those skilled in the art. Therefore, the specification and drawings are only for the purpose of clearly describing a certain embodiment and do not mean that the composition and / or sequence are necessary.

[0024] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0025] An optical inspection system is disclosed in an embodiment of the present application. The optical inspection system can use the principle of optical imaging to achieve bright field imaging and dark field imaging of surface defects of a product under inspection.

[0026] Before introducing the optical detection system of the embodiment of the present application, the general structure of the optical detection system in the conventional product is first introduced. Figure 1 and Figure 2 In the previous products, the optical detection system includes a bright field light source 100, a dark field light source 200, a bright field lighting lens group 110, a dark field lighting lens group 210 and an image acquisition device 300. The bright field light source 100 is used to generate a bright field illumination beam, and the dark field light source 200 is used to generate a dark field illumination beam; the bright field illumination lens group 110 is located on the transmission path of the bright field illumination beam, and is used to guide and adjust the bright field illumination beam to irradiate the measured surface of the measured product (not shown in the figure); the dark field illumination lens group 210 is located on the transmission path of the dark field illumination beam, and is used to guide and adjust the dark field illumination beam to irradiate the measured surface of the measured product; the image acquisition device 300 is used to acquire the first signal light 410 generated by the reflection of the first detection light 400 formed by the bright field illumination beam adjusted by the bright field illumination lens group 110 on the surface of the measured product, and obtain a bright field image of the measured product, and is also used to acquire the second signal light 510 generated by the scattering of the second detection light 500 formed by the dark field illumination beam adjusted by the dark field illumination lens group 210 on the surface of the measured product, and obtain a dark field image of the measured product, and the defects on the surface of the measured product can be distinguished by identifying the bright field image and the dark field image.

[0027] Please refer to Figure 1 During the bright field detection process, the bright field illumination beam will form a second stray light 430 after passing through the bright field illumination lens group 110. The second stray light 430 includes the light formed after the first detection light 400 is reflected or scattered by an optical element (such as a lens) in the bright field illumination lens group 110, and also includes the light formed after the first detection light 400 is reflected or scattered on the surface of the product being tested after passing through the bright field illumination lens group 110. Please refer to Figure 1As shown by the middle dotted line, the second stray light 430 will be received by the dark field illumination lens group 210 and reflected and mixed into the transmission path of the second detection light 500, that is, it will be collected by the image acquisition device 300 along the transmission path of the second detection light 500, and form a bright field interference image in the image acquisition device 300. The bright field interference image will affect the imaging quality and imaging effect of the bright field image, and reduce the detection efficiency and detection accuracy of product surface defects.

[0028] Similarly, please refer to Figure 2 During the dark field detection process, the dark field illumination light beam will form a first stray light 530 after passing through the dark field illumination lens group 210. The first stray light 530 includes the light formed after the second detection light 500 is reflected or scattered by an optical element (such as a lens) in the dark field illumination lens group 210, and also includes the light formed after the second detection light 500 is reflected or scattered on the surface of the product being tested after passing through the dark field illumination lens group 210. Please refer to Figure 2 As shown by the middle dotted line, these first stray lights 530 will be received by the bright field illumination lens group 110 and reflected and mixed into the transmission path of the first detection light 400, that is, they will be collected by the image acquisition device 300 along the transmission path of the first detection light 400, and form a dark field interference image in the image acquisition device 300. The dark field interference image will affect the imaging quality and imaging effect of the dark field image, and reduce the detection efficiency and detection accuracy of product surface defects.

[0029] Since the image acquisition device 300 is very sensitive to light in dark field imaging, a small amount of first stray light 530 will seriously affect the imaging quality and imaging effect of the dark field image, thereby reducing the detection efficiency and detection accuracy of product surface defects.

[0030] To overcome the adverse effects of beam reflection on imaging quality in previous optical inspection systems, please refer to Figure 3 and Figure 4 The optical detection system of the embodiment of the present application sets a first optical element 111 in the bright field illumination lens group 11, sets a second optical element 211 in the dark field illumination lens group 21, and sets the polarization directions of the first optical element 111 and the second optical element 211 to be different, so that the first stray light 53 is suppressed from being reflected by the bright field illumination lens group 11 by the first optical element 111, and the second stray light 43 is suppressed from being reflected by the dark field illumination lens group 21 by the second optical element 211. In this way, the adverse effect of stray light on the imaging quality and imaging effect of bright field images and dark field images can be reduced, which helps to improve the detection efficiency and detection accuracy of the optical detection system.

[0031] For details, please continue to refer to Figure 3 and Figure 4The optical inspection system of the embodiment of the present application includes a bright field light source 10, a dark field light source 20, a bright field illumination lens group 11, a dark field illumination lens group 21 and an image acquisition device 3. The bright field light source 10, the dark field light source 20 and the image acquisition device 3 are all installed on the upper side of the carrying device 6 in the optical inspection equipment. The product to be tested is carried on the carrying device 6 and is located in the inspection field of view. The bright field light source 10 is used to generate a bright field illumination beam, and the dark field light source 20 is used to generate a dark field illumination beam. Both the bright field light source 10 and the dark field light source 20 can be a white light source or a laser light source of a certain color.

[0032] The bright field illumination lens group 11 and the dark field illumination lens group 21 are both installed on the upper side of the carrying device 6. The bright field illumination lens group 11 is located on the optical path of the bright field illumination beam, and is used to guide and adjust the bright field illumination beam to irradiate the measured surface of the measured product. The dark field illumination lens group 21 is located on the optical path of the dark field illumination beam, and is used to guide and adjust the dark field illumination beam to irradiate the measured surface of the measured product. The image acquisition device 3 is installed on the upper side of the carrying device 6. The image acquisition device 3 is used to collect the first signal light 41 generated by the first detection light formed by the bright field illumination beam after being adjusted by the bright field illumination lens group 11 and reflected on the surface of the measured product, and obtain the bright field image of the measured product; the image acquisition device 3 is also used to collect the second signal light 51 generated by the second detection light formed by the dark field illumination beam after being adjusted by the dark field illumination lens group 21 and scattered on the surface of the measured product, and obtain the dark field image of the measured product. By identifying the bright field image and the dark field image, the defects on the surface of the measured product can be distinguished.

[0033] Please refer to Figure 3 and Figure 4 The bright field illumination lens group 11 includes a first optical element 111, and the dark field illumination lens group 21 includes a second optical element 211. Both the first optical element 111 and the second optical element 211 can be polarizers or Nicol prisms. The first optical element 111 is used to change the bright field illumination beam into a first linear polarized light 40, which is the first detection light; the second optical element 211 is used to change the dark field illumination beam into a second linear polarized light 50, which is the second detection light; the polarization direction of the first optical element 111 and the polarization direction of the first linear polarized light 40 are both the first direction, the polarization direction of the second optical element 211 and the polarization direction of the second linear polarized light 50 are both the second direction, and the first direction is different from the second direction. The first optical element 111 and the second optical element 211 are both lenses with high transmittance and anti-reflection film on the surface, and they reflect very little light themselves, and the reflected light is not enough to affect the bright field image and the dark field image.

[0034] For details about the dark field imaging process in some embodiments, please refer to Figure 3The dark field illumination light beam generated by the dark field light source 20 is adjusted by the dark field illumination lens group 21 to form a second detection light, that is, to form a second linear polarized light 50. The second detection light is scattered by the surface of the product to be measured to form a second signal light 51. The second signal light 51 is collected by the image acquisition device 3 to form a dark field image of the surface of the product to be measured in the image acquisition device 3. After the dark field illumination light beam passes through the dark field illumination lens group 21, a first stray light 53 is also formed. The first stray light 53 includes the light that reaches the bright field illumination lens group 11 after the second detection light is reflected and / or scattered; for example, the first stray light 53 includes the light that is formed after the second detection light is reflected or scattered by the edge of the optical element in the dark field illumination lens group 21, and also includes the light that is formed after the second detection light is reflected or scattered on the surface of the product to be measured.

[0035] Since the dark field illumination lens assembly 21 includes the second optical element 211, the first stray light 53 formed by the dark field illumination light beam passing through the dark field illumination lens assembly 21 also passes through the second optical element 211, so the first stray light 53 is linearly polarized light, and its polarization direction is the second direction. Figure 3 Since the polarization direction of the first optical element 111 is different from the polarization direction of the second optical element 211, please refer to Figure 3 As shown by the middle dotted line, the first optical element 111 in the bright field illumination lens group 11 can suppress the passage of the first stray light 53 having a polarization direction in the second direction, that is, the first optical element 111 can suppress the first stray light 53 from being mixed into the transmission path of the first detection light, and can reduce the probability of the first stray light 53 being reflected by the bright field illumination lens group 11 and being transmitted along the transmission direction of the first detection light and the first signal light 41 during the bright field imaging process, thereby reducing the probability of forming a dark field interference image in the image acquisition device 3, helping to ensure the imaging quality and imaging effect of the dark field image, and improving the detection efficiency and detection accuracy of the optical detection system.

[0036] In some embodiments, during bright field imaging, please refer to Figure 4 The bright field illumination beam generated by the bright field light source 10 is adjusted by the bright field illumination lens group 11 to form the first detection light, that is, to form the first linear polarized light 40. The first detection light is reflected by the surface of the product to be detected to form the first signal light 41. The first signal light 41 is collected by the image acquisition device 3 to form a bright field image of the surface of the product to be detected in the image acquisition device 3. After the bright field illumination beam passes through the bright field illumination lens group 11, the second stray light 43 is also formed. The second stray light 43 includes the light that reaches the dark field illumination lens group 21 after the first detection light is reflected and / or scattered; for example, the second stray light 43 includes the light that is formed after the first detection light is reflected or scattered by the edge of the optical element in the bright field illumination lens group 11, and also includes the light that is formed after the first detection light is reflected or scattered on the surface of the product to be detected.

[0037] To reduce the adverse effects of bright field interference images on bright field images, please refer to Figure 4 The second optical element 211 is provided to suppress the second stray light 43 from mixing into the transmission path of the second detection light. Figure 4 Since the second stray light 43 formed after the bright field illumination beam passes through the bright field illumination lens group 11 also passes through the first optical element 111, the second stray light 43 is linearly polarized light, and its polarization direction is the first direction. The polarization direction of the first optical element 111 is different from the polarization direction of the second optical element 211, so please refer to Figure 4 As shown by the middle dotted line, the second optical element 211 can suppress the passage of the second stray light 43 with a polarization direction in the first direction, and can reduce the probability of the second stray light 43 being reflected by the dark field illumination lens group 21 and transmitted along the transmission direction of the second detection light and the second signal light 51, thereby reducing the probability of forming a bright field interference image in the image acquisition device 3, helping to ensure the imaging quality and imaging effect of the bright field image, and improving the detection efficiency and detection accuracy of the optical detection system.

[0038] In some embodiments, an orthogonal relationship may be set between the polarization direction of the first optical element 111 and the polarization direction of the second optical element 211, that is, an orthogonal relationship may be set between the polarization direction of the first linear polarized light 40 and the polarization direction of the second linear polarized light 50, that is, the two directions differ by 90 degrees, so as to maximize the guarantee that the first stray light 53 generated after the second linear polarized light 50 is reflected and / or scattered cannot pass through the first optical element 111, and also guarantee that the second stray light 43 generated after the first linear polarized light 40 is reflected and / or scattered cannot pass through the second optical element 211, thereby ensuring that the adverse effect of the second stray light 43 on the bright field image can be reduced or even avoided, and ensuring that the adverse effect of the first stray light 53 on the dark field image can be reduced or even avoided.

[0039] In some embodiments, the angle between the polarization direction of the first optical element 111 and the polarization direction of the second optical element 211 can be set to 20°, 30°, 50° or 80°. As the angle gradually increases, the effect of the first optical element 111 in suppressing the passage of the first stray light 53 becomes more obvious, and the effect of the second optical element 211 in suppressing the passage of the second stray light 43 becomes more obvious. In this way, the adverse effect of the second stray light 43 on the bright field image becomes smaller and smaller, and the adverse effect of the first stray light 53 on the dark field image also becomes smaller and smaller. The imaging quality and imaging effect of the bright field image and the dark field image are getting higher and higher, and the detection efficiency and accuracy of product surface defects are also getting higher and higher.

[0040] For some examples, please refer to Figure 3 and Figure 4For the first optical element 111, the first optical element 111 is located on the light-emitting side of the bright field illumination lens group 11 in the optical path of the bright field illumination light beam. For example, the bright field illumination lens group 11 may include a bright field illumination lens barrel extending in the transmission direction of the bright field illumination light beam. The bright field illumination lens barrel has a first end for the bright field illumination light beam to be incident on and a second end for the first linear polarized light 40 to be emitted in its extension direction. The first optical element 111 may be installed at the second end of the bright field illumination lens barrel in the extension direction, so that the bright field illumination light beam is transmitted in the bright field illumination lens barrel until it is changed into the first linear polarized light 40 by the first optical element 111 at the second end. In this way, not only can the first optical element 111 suppress the first stray light 53 from mixing into the transmission path of the first linear polarized light 40, but also the first stray light 53 can be suppressed from entering the bright field illumination lens group 11 in the direction opposite to the transmission direction of the bright field illumination light beam, and the first stray light 53 reflected by other components in the bright field illumination lens group 11, such as the wall of the bright field illumination lens barrel, can be suppressed from mixing into the transmission path of the first linear polarized light 40, and the adverse effect of the first stray light 53 on the imaging quality and imaging effect of the dark field image can be further reduced, thereby further improving the detection efficiency and accuracy of product surface defects.

[0041] Correspondingly, in some embodiments, for the second optical element 211, the second optical element 211 is located on the light-emitting side of the dark-field illumination lens group 21 in the optical path of the dark-field illumination light beam. For example, the dark-field illumination lens group 21 may include a dark-field illumination lens barrel extending in the transmission direction of the dark-field illumination light beam. The dark-field illumination lens barrel has a third end for the incidence of the dark-field illumination light beam and a fourth end for the emission of the second linear polarized light 50 in its extension direction. The second optical element 211 may be installed at the fourth end of the dark-field illumination lens barrel in the extension direction. In this way, the dark-field illumination light beam is transmitted in the dark-field illumination lens barrel until it is changed into the second linear polarized light 50 by the second optical element 211 at the fourth end of the dark-field illumination lens barrel. In this way, not only can the second optical element 211 suppress the second stray light 43 from mixing into the transmission path of the second linearly polarized light 50, but also the second stray light 43 can be suppressed from entering the dark field illumination lens group 21 in the direction opposite to the transmission direction of the dark field illumination light beam, and the second stray light 43 reflected by other components in the dark field illumination lens group 21, such as the barrel wall of the dark field illumination lens barrel, can be suppressed from mixing into the transmission path of the second linearly polarized light 50, and the adverse effect of the second stray light 43 on the imaging quality and imaging effect of the bright field image can be further reduced, thereby further improving the detection efficiency and accuracy of product surface defects.

[0042] For some examples, please refer to Figure 4The first linear polarized light 40 emitted by the bright field illumination lens group 11 forms a first angle with the surface of the product under test. The surface of the product under test can be understood as the upper surface of the product under test, which is the tested surface of the product under test, and the upper surface is parallel to the horizontal plane. The range of the first angle is 35° to 85°, so that most of the first signal light 41 after the first linear polarized light 40 is reflected by the tested surface of the product under test can be collected by the image acquisition device 3, so that the image acquisition device 3 can obtain a bright field image with a better imaging effect according to the collected first signal light 41.

[0043] Specifically, in one embodiment, the first angle can be the angle between the extension direction of the bright field illumination lens barrel and the horizontal plane. The first angle can be 35°, 50°, 65° or 80°. The specific angle value of the first angle can be selected according to different types of defects to increase the number of defect types and defect clarity in the bright field image, thereby improving the efficiency of product surface defect detection.

[0044] For some embodiments, please continue to refer to Figure 3 The second linear polarized light 50 emitted by the dark field illumination lens group 21 forms a second angle with the surface of the product under test, and the range of the second angle is 20° to 70°, so that most of the second signal light 51 after the second linear polarized light 50 is scattered by the measured surface of the product under test can be collected by the image acquisition device 3, and the image acquisition device 3 can obtain a dark field image with a better imaging effect according to the collected second signal light 51.

[0045] Specifically, in one embodiment, the second angle may be the angle between the direction of extension of the emitted light of the dark field illumination lens barrel and the horizontal plane, and the second angle may also be 20°, 30°, 40°, 50°, 60° or 70°. The specific angle value of the second angle may be selected according to different types of defects to increase the number of defect types and defect clarity in the dark field image, thereby improving the efficiency of product surface defect detection. Of course, in other embodiments, according to the requirements of the defect type, the second angle may be greater than 70° in special cases.

[0046] During the dark field detection process, the scattered light of the second linear polarized light 50 generated by a single light source on the surface of the product being tested is collected by the image acquisition device 3, and the image acquisition device 3 obtains a dark field image. In this way, the dark field image may have poor imaging effect due to the direction and uniformity of the light, which will reduce the detection effect and accuracy of the product. In some embodiments, please continue to refer to Figure 3 and Figure 4The number of dark field light sources 20 and dark field lighting mirror groups 21 can be set to be multiple, such as two, three or four; multiple dark field lighting mirror groups 21 correspond one-to-one to multiple dark field light sources 20. Among the multiple one-to-one corresponding dark field light sources 20 and dark field lighting mirror groups 21, different dark field light sources 20 can illuminate the product under test from different directions, thereby more comprehensively highlighting the edges and fine structures of surface defects of the product under test, adapting to different detection requirements, and improving detection effect and accuracy.

[0047] Furthermore, in some embodiments, the optical axes of two of the multiple dark field illumination lens groups 21 may be arranged symmetrically about the normal of the product to be measured, the normal of the product to be measured is perpendicular to the upper surface of the product to be measured, that is, to the measured surface on the product to be measured, and the optical axis direction of the dark field illumination lens group 21 is the extension direction of the dark field illumination lens barrel in the dark field illumination lens group 21; the optical axes of the two dark field illumination lens groups 21 are symmetrical about the normal of the product to be measured, that is, the angles between the optical axis directions of the two dark field illumination light beams or the optical axis directions of the two second linear polarized lights 50 and the horizontal plane are equal, so that the first linear polarized light 40 can be uniformly irradiated on the measured surface of the product to be measured, thereby reducing unnecessary shadows and reflections and improving imaging clarity and contrast; and the two second linear polarized lights 50 are symmetrically arranged, so that the object can be illuminated from different angles, thereby improving the sensitivity of defect detection.

[0048] Of course, in other embodiments, the angles between the optical axes and the horizontal plane in the plurality of dark field illumination lens groups 21 may be unequal according to different detection requirements.

[0049] For some examples, please refer to Figure 3 and Figure 4 The optical inspection system includes a first adjustment component 12, which is used to adjust the pitch angle and / or position of the bright field illumination lens group 11. The pitch angle and / or position of the bright field illumination lens barrel in the bright field illumination lens group 11 can be changed by the first adjustment component 12 to change the spot size and position of the first linear polarized light 40 in the inspection field of view to adapt to different defect types and improve the optical inspection system's ability to detect surface defects of the product being inspected.

[0050] Correspondingly, in some embodiments, please refer to Figure 3 and Figure 4 The optical inspection system also includes a second adjustment component 22, which is used to adjust the pitch angle and / or position of the dark field illumination lens group 21. The pitch angle and / or position of the dark field illumination lens barrel in the dark field illumination lens group 21 can be changed by the second adjustment component 22 to change the spot size and position of the second linear polarized light 50 in the inspection field of view to adapt to different defect types and improve the optical inspection system's ability to detect surface defects of the product being inspected.

[0051] Specifically, the first adjustment component 12 and the second adjustment component 22 may include a fine-tuning screw, a fixing part, and a movable part. The position of the fixing part and the carrying device 6 is relatively fixed. The movable part is used to install and fix the corresponding dark field illumination lens barrel or bright field illumination lens barrel. The movable part can be connected to the fixing part through a fine-tuning screw. By screwing the fine-tuning screw, the movable part can be driven to move relative to the fixed part, thereby realizing the adjustment of the pitch angle and / or position of the dark field illumination lens barrel or the bright field illumination lens barrel relative to the fixed part. After the bright field illumination lens barrel and the dark field illumination lens barrel are adjusted into place, the relative fixation of the movable part and the fixed part can be realized by tightening the screw.

[0052] Of course, in order to achieve different imaging angles, in some embodiments, please continue to refer to Figure 3 and Figure 4 The optical detection system may also include a third adjustment component 30, which is used to adjust the pitch angle and / or position of the image acquisition device 3 to adapt to different defect types and improve the defect detection capability of the optical detection system.

[0053] Please continue to refer to Figure 3 and Figure 4 The image acquisition device 3 includes a lens 32 and a camera 31. The lens 32 is used to collect the first signal light 41 during the bright field detection process and to collect the second signal light 51 during the dark field detection process. The lens 32 is also used to focus the first signal light 41 and the second signal light 51 on the imaging plane of the camera 31, so that the camera 31 can obtain a bright field image during the bright field detection process and a dark field image during the dark field detection process.

[0054] The third adjustment component 30 may be similar in structure to the first adjustment component 12 and the second adjustment component 22. The third adjustment component 30 includes a fine-tuning screw, a fixed part and a movable part. The position of the fixed part and the supporting device 6 is relatively fixed. The movable part is used to install and fix the image acquisition device 3. The movable part is connected to the fixed part through a fine-tuning screw. By screwing the fine-tuning screw, the movable part is driven to move relative to the fixed part, thereby realizing the adjustment of the pitch angle and / or position of the image acquisition device 3 relative to the supporting device 6. After the image acquisition device 3 is adjusted into place, the relative fixation of the movable part and the fixed part can be realized by tightening the screw.

[0055] Of course, in other embodiments, the first adjustment component 12, the second adjustment component 22 and the third adjustment component 30 may be eliminated respectively, so as to simplify the structure of the optical inspection system while satisfying the optical inspection system's detection of specific defect types on the inspected product.

[0056] The present application also provides an optical detection device, please refer to Figure 3 and Figure 4The optical inspection device includes a carrying device 6 and an optical inspection system in any of the above embodiments. The carrying device 6 is used to carry and limit the product to be tested and drive the product to be tested to move. The optical inspection system performs optical inspection on the product to be tested on the carrying device 6.

[0057] In some embodiments, the supporting device 6 may include a supporting platform 62 and a limiting structure. The supporting platform 62 is used to support the product under test. The limiting structure is installed on the supporting platform 62 and is used to limit the movement of the product under test relative to the supporting platform 62. For example, the limiting structure can press the product under test onto the supporting platform 62 by a press-fitting method, or the limiting structure includes an adsorption component 61, such as a suction cup, which fixes the product under test on the supporting platform 62 by vacuum adsorption.

[0058] In some embodiments, the optical detection device further includes a driving mechanism 8, which is connected to the carrying device 6 and spatially isolated from the optical detection system. The driving mechanism 8 is used to drive the carrying device 6 to perform linear movement relative to the optical detection system.

[0059] The driving mechanism 8 is located at the lower side of the optical detection system. The driving mechanism 8 is arranged at an interval with the optical detection system. The driving mechanism 8 may include one or more servo drive motors. The driving mechanism 8 is transmission-connected to the carrying device 6 to drive the carrying device 6 and the product under test to move linearly in the horizontal plane. The optical detection system can realize line scanning imaging of the product under test during the linear movement of the product under test to improve the detection effect and accuracy of surface defects of the product under test.

[0060] In some embodiments, the optical inspection device has a bright field inspection mode and a dark field inspection mode. In the bright field inspection mode, the dark field light source 20 is turned off, the bright field light source 10 generates a bright field illumination beam, and the image acquisition device 3 obtains a bright field image of the product under inspection; in the dark field inspection mode, the bright field light source 10 is turned off, the dark field light source 20 generates a dark field illumination beam, and the image acquisition device 3 obtains a dark field image of the product under inspection. The use of both bright field and dark field inspection modes can improve the optical inspection device's ability to detect different types of defects on the product under inspection, and help improve the inspection effect and inspection accuracy of the optical inspection device.

[0061] In some embodiments, the optical inspection device may also adopt other inspection modes, such as only adopting the dark field inspection mode to detect surface defects of the product under inspection according to the characteristics of the product under inspection, and during the dark field inspection process, the dark field light source 20 may generate dark field illumination beams with different spectral bands to meet the inspection requirements of the product under inspection. Alternatively, in other embodiments, the optical inspection device may also only adopt the bright field inspection mode to detect surface defects of the product under inspection, and during the inspection process, the bright field light source 10 may also generate bright field illumination beams with different spectral bands to meet the inspection requirements of the product under inspection.

[0062] The above specific examples are used to illustrate the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the art, according to the concept of the present invention, some simple deductions, modifications or substitutions can be made.

Claims

1. An optical detection system, characterized in that: include: A bright field light source, used for generating a bright field illumination beam; A dark field light source, used for generating a dark field illumination beam; A bright field illumination lens assembly is arranged on the optical path of the bright field illumination light beam, and the bright field illumination lens assembly comprises a first optical element, and the first optical element is used to change the bright field illumination light beam into a first linearly polarized light; A dark field illumination mirror group, arranged on the optical path of the dark field illumination light beam, the dark field illumination mirror group comprising a second optical element, the second optical element being used to change the dark field illumination light beam into a second linearly polarized light; the polarization direction of the first linearly polarized light is different from the polarization direction of the second linearly polarized light; the first optical element is also used to suppress first stray light from being mixed into the transmission path of the first linearly polarized light, the first stray light comprising the light of the second linearly polarized light reaching the bright field illumination mirror group after being reflected and / or scattered; An image acquisition device, used to acquire a first signal light generated by the reflection of the first linear polarized light on the surface of the product under test, and obtain a bright field image of the product under test, or to acquire a second signal light generated by the scattering of the second linear polarized light on the surface of the product under test, and obtain a dark field image of the product under test; The first optical element is located on the light exit side of the bright field illumination lens group in the optical path of the bright field illumination light beam; the second optical element is located on the light exit side of the dark field illumination lens group in the optical path of the dark field illumination light beam.

2. The optical detection system according to claim 1, characterized in that: There is an orthogonal relationship between the polarization direction of the first linear polarized light and the polarization direction of the second linear polarized light.

3. The optical detection system according to claim 1, characterized in that: The first linearly polarized light emitted by the bright field illumination lens group forms a first angle with the surface of the product to be measured, and the range of the first angle is 60°±25°; and / or, The second linearly polarized light emitted by the dark field illumination lens group forms a second angle with the surface of the product to be measured, and the range of the second angle is 45°±25°.

4. The optical detection system according to claim 1, characterized in that: The second optical element is also used to suppress second stray light from mixing into the transmission path of the second linearly polarized light, where the second stray light includes light from the first linearly polarized light that reaches the dark field illumination lens assembly after being reflected and / or scattered.

5. The optical detection system according to any one of claims 1 to 4, characterized in that: The first optical element and the second optical element are both polarizing plates or Nicol prisms.

6. The optical detection system according to any one of claims 1 to 4, characterized in that: There are multiple dark field light sources and multiple dark field illumination mirror groups, and the multiple dark field illumination mirror groups correspond one to one to the multiple dark field light sources; and the optical axes of two of the multiple dark field illumination mirror groups are symmetrically arranged about the normal line of the product to be measured.

7. The optical detection system according to any one of claims 1 to 4, characterized in that: The optical detection system comprises a first adjustment component, wherein the first adjustment component is used to adjust the pitch angle and / or position of the bright field illumination lens assembly; and / or, The optical detection system comprises a second adjustment component, and the second adjustment component is used to adjust the pitch angle and / or position of the dark field illumination lens group.

8. The optical detection system according to any one of claims 1 to 4, characterized in that: The optical detection system comprises a third adjustment component, and the third adjustment component is used to adjust the pitch angle and / or position of the image acquisition device.

9. An optical detection device, characterized in that: It comprises a carrying device and the optical inspection system described in any one of claims 1 to 8, wherein the carrying device is used to carry and limit the product to be tested and drive the product to be tested to move, and the optical inspection system performs optical inspection on the product to be tested on the carrying device.

10. The optical detection device according to claim 9, characterized in that: The optical inspection device has a bright field inspection mode and a dark field inspection mode; in the bright field inspection mode, the bright field light source generates a bright field illumination beam, and the image acquisition device obtains a bright field image of the product under inspection; In the dark field detection mode, the dark field light source generates a dark field illumination beam, and the image acquisition device obtains a dark field image of the product under test.

11. The optical detection device according to claim 9, characterized in that: It also includes a driving mechanism, which is connected to the carrying device and spatially isolated from the optical detection system, and is used to drive the carrying device to perform linear movement relative to the optical detection system.

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