Light and dark field optical detection device

Abstract

The embodiment of the invention discloses a bright and dark field optical detection device which is used for simultaneously carrying out bright field detection and dark field detection so as to improve the detection efficiency of the bright and dark field detection device. The device comprises a bright field light source used for emitting a bright field light beam and enabling the bright field light beam to reach a first optical assembly; the dark field light source is used for emitting a dark field light beam reaching the object to be measured; the first optical assembly is used for guiding the bright field light beam to irradiate the to-be-measured object, receiving bright field signal light generated by the bright field light beam on the surface of the to-be-measured object and guiding the light field signal light to the second optical assembly, and receiving dark field signal light generated by the dark field light beam on the surface of the to-be-measured object and guiding the dark field signal light to the second optical assembly; transmission paths of the bright field signal light and the dark field signal light do not coincide in space; the second optical assembly is used for guiding the bright field signal light to reach a bright field camera and guiding the dark field signal light to reach a dark field camera.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optics, and in particular to a bright-field and dark-field optical detection device. Background Art

[0002] Brightfield detection is a crucial method in optical inspection. However, brightfield detection is limited by the diffraction limit, with the smallest detectable defect being only the radius of the Airey disk. Darkfield detection, on the other hand, relies on Rayleigh or Mie scattering from small particles. By detecting the scattered signals from small defects, it can improve detection sensitivity. Therefore, to enhance detection sensitivity, a darkfield device is often added to a brightfield device to create a bright / darkfield detection system.

[0003] Generally, the intensity of a brightfield beam is much greater than that of a darkfield beam, causing significant interference. In existing brightfield and darkfield detection devices, the brightfield and darkfield optical axes are co-located. To eliminate this interference, the detection device must be run twice, performing both brightfield and darkfield detection independently.

[0004] In order to eliminate the interference of the bright field beam with higher light intensity on the dark field beam, the bright and dark field detection device needs to perform bright field detection and dark field detection asynchronously, which leads to low detection efficiency of the existing bright and dark field detection device. Summary of the Invention

[0005] An embodiment of the present application provides a bright-field and dark-field optical detection device for simultaneously performing bright-field detection and dark-field detection to improve the detection efficiency of the bright-field and dark-field detection device.

[0006] A first aspect of an embodiment of the present application provides a bright-field and dark-field optical detection device, comprising:

[0007] a bright field light source, configured to emit a bright field light beam and allow the bright field light beam to reach the first optical component;

[0008] A dark field light source, used to emit a dark field light beam to the object to be measured;

[0009] The first optical component is configured to guide the brightfield light beam to illuminate the object to be measured, receive the brightfield signal light generated by the brightfield light beam on the surface of the object to be measured and guide it to the second optical component, and receive the darkfield signal light generated by the darkfield light beam on the surface of the object to be measured and guide it to the second optical component; the transmission paths of the brightfield signal light and the darkfield signal light do not overlap in space;

[0010] The second optical component is used to guide the bright field signal light to a bright field camera, and to guide the dark field signal light to a dark field camera.

[0011] In a specific implementation, the second optical component includes a beam splitting prism. The first beam splitting surface of the beam splitting prism is used to receive the bright field signal light and reflect or transmit it to the bright field camera, and the second beam splitting surface of the beam splitting prism is used to receive the dark field signal light and reflect or transmit it to the dark field camera;

[0012] Or,

[0013] the second optical component includes a first mirror and a second mirror. The first mirror is used to receive the bright field signal light and reflect it to the bright field camera, and the second mirror is used to receive the dark field signal light and reflect it to the dark field camera.

[0014] In a specific implementation, the dark field light source includes a plurality of dark field light emitting components. Each of the dark field light emitting components is symmetrically arranged about a preset optical axis of space, and the irradiation beams of each of the dark field light emitting components form the dark field signal light on the surface of the object to be measured, and the dark field signal light is transmitted along the preset optical axis.

[0015] In a specific implementation, the optical axis of the bright field signal light is symmetric about the system optical axis of the bright and dark field optical detection device with the optical axis of the dark field signal light, and the interval between the optical axis of the bright field signal light and the optical axis of the dark field signal light is 0 to 2 millimeters.

[0016] In a specific implementation, it further includes:

[0017] A filtering component, which is used to filter out the light in the target wavelength band from the bright field light beam emitted from the bright field light source, and make the bright field light beam after being processed by the filtering component reach the first optical component. The target wavelength band includes the wavelength band where the background color of the object to be measured is located.

[0018] In a specific implementation, it further includes:

[0019] An objective lens, which is used to receive the bright field signal light and the dark field signal light generated on the surface of the object to be measured, and emit them to the second optical component after being magnified by optical imaging;[[ID=z5]]

[0020] An autofocus component, which is used to emit a detection beam, measure the defocus amount of the object to be measured relative to the objective lens based on the detection beam, and assist the objective lens to focus on the object to be measured.

[0021] In a specific implementation, it further includes:

[0022] A spatial filtering component, which is used to adjust the angular spectrum frequency of the illumination light beam irradiated on the object to be measured. The spatial filtering component is conjugate to the aperture stop of the objective lens.

[0023] In a specific implementation, for the re-inspection of the object to be measured, the magnification of the objective lens is greater than that of the objective lens used for the initial inspection of the object to be measured.

[0024] In a specific implementation, it further includes:

[0025] A steering component for causing the illumination beam emitted from the bright-field light source to reach the first optical component after being deflected.

[0026] In a specific implementation, the diameter of the imaging field of view of the bright and dark field optical detection device is where D is the diameter of the imaging field of view of the bright and dark field optical detection device, 1 is the length of the camera target surface, w is the width of the camera target surface, and d is the bright and dark field interval between the bright field optical axis and the dark field optical axis. The lengths and widths of the camera target surfaces of the bright field camera and the dark field camera are the same.

[0027] As can be seen from the above technical solutions, the embodiments of the present application have the following advantages: Different from the design of the existing bright and dark field optical detection devices, in the embodiments of the present application, the bright field optical axis and the dark field optical axis do not coincide. Therefore, the bright field light beam can pass through the first optical component along the bright field optical axis to reach the object to be measured, and the formed bright field signal light continues to pass through the first optical component along the bright field optical axis to reach the second optical component; the formed dark field signal light can pass through the first optical component along the dark field optical axis to reach the second optical component; finally, after the dark field signal light and the bright field signal light are respectively incident on the second optical component, the second optical component can respectively cause the bright field signal light to reach the bright field camera and the dark field signal light to reach the dark field camera. Since the transmission paths of the bright field signal light and the dark field signal light do not coincide in space, even if the bright field detection and the dark field detection are carried out synchronously, the bright field signal light will not cause obvious interference to the dark field signal light. And synchronously carrying out the bright field detection and the dark field detection can effectively improve the detection efficiency of the bright and dark field detection device. Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments recorded in the present application. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings.

[0029] Figure 1 It is a structural schematic diagram of the bright and dark field optical detection device disclosed in the embodiments of the present application;

[0030] Figure 2 It is another structural schematic diagram of the bright and dark field optical detection device disclosed in the embodiments of the present application;

[0031] Figure 3This is a schematic diagram of the imaging field of view of the bright and dark field optical detection device disclosed in the embodiments of the present application. Detailed implementation manners

[0032] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0033] In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the embodiments of the present application. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0034] In the description of the embodiments of the present application, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", and "connected" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific situations.

[0035] Please refer to Figure 1 , the embodiments of the present application disclose a bright and dark field optical detection device, including:

[0036] A bright field light source 10 for emitting a bright field light beam and causing the bright field light beam to reach a first optical component 30;

[0037] A dark field light source 20 for emitting a dark field light beam that reaches a test object 160;

[0038] A first optical component 30 for guiding the bright field light beam to irradiate the test object 160, receiving the bright field signal light generated on the surface of the test object 160 by the bright field light beam and guiding it to a second optical component 40, and receiving the dark field signal light generated on the surface of the test object 160 by the dark field light beam and guiding it to the second optical component 40; the transmission paths of the bright field signal light and the dark field signal light do not overlap in space;

[0039] The second optical component 40 is used to guide the bright-field signal light to the bright-field camera 60 and guide the dark-field signal light to the dark-field camera 50.

[0040] It can be understood that the optical axes in the optical detection device are all artificially defined during the construction of the optical detection device, and each optical component is arranged according to the artificially defined optical axis to meet the expected detection effect of the design. In the embodiments of the present application, the optical axis of the bright-field light beam and the optical axis of the bright-field signal light always coincide, and the optical axis of the dark-field light beam and the optical axis of the dark-field signal light always coincide. Among them, Figure 1 the yellow dashed line indicates the bright-field light beam, the yellow solid line indicates the bright-field signal light, the green dashed line indicates the dark-field light beam, the green solid line indicates the dark-field signal light, the position where the yellow dashed line is located is the optical axis of the bright-field light beam, the position where the yellow solid line is located is the optical axis of the bright-field signal light, the position where the green dashed line is located is the optical axis of the dark-field light beam, the position where the green solid line is located is the optical axis of the dark-field signal light, and the position where the red line is located is the system optical axis of the bright-field and dark-field optical detection device in the embodiments of the present application.

[0041] Specifically, the bright-field light source 10 is used to emit a bright-field light beam along the bright-field optical axis, and the first optical component 30 is used to transmit the bright-field light beam to the object to be measured 160; the dark-field light source 20 is used to emit a dark-field light beam that reaches the object to be measured 160. The bright-field signal light will enter the first optical component 30 from the surface of the object to be measured 160 along the bright-field optical axis, and the dark-field signal light will enter the first optical component 30 from the surface of the object to be measured 160 along the dark-field optical axis. In order to distinguish the bright-field light beam transmitted from the first optical component 30 and the signal light (including the bright-field signal light and the dark-field signal light) incident on the first optical component 30 to obtain the imaging of the surface of the object to be measured 160, in the embodiments of the present application, the first optical component 30 needs to make the signal light reach the second optical component 40. Finally, the bright-field signal light and the dark-field signal light reach the bright-field camera 60 and the dark-field camera 50 respectively through the second optical component 40. Among them, the bright-field light source 10 can be a light source with a relatively large optical power such as a linear optical fiber or a point light source, and the dark-field light source 20 can be any light source that meets the detection requirements; the bright-field camera 60 and the dark-field camera 50 can be a line-scan camera or a surface-scan camera, etc. The line-scan camera can specifically be a line-scan camera using integral delay; the first optical component 30 can be an optical device with specific transmittance and reflectivity, and the sum of the transmittance and reflectivity of the first optical component 30 is 1. Furthermore, the optical efficiency of the bright-field signal light is the product of the transmittance and the reflectivity, and the optical efficiency of the dark-field signal light is the reflectivity. In practical applications, in order to balance the bright-field optical efficiency and the dark-field optical efficiency, it is necessary to make the optical efficiency of the bright-field signal light as close as possible to the optical efficiency of the dark-field signal light.

[0042] It should be noted that for the dark-field detection system, the dark-field light beam irradiates the object to be measured 160 at a specific angle and in a specific manner. When the dark-field light source 20 irradiates the object to be measured 160, different parts of the object to be measured 160 will result in different diffraction intensities due to differences in their structures or orientations. This difference in diffraction intensity further forms the contrast of the bright and dark field images, that is, the brightness and darkness differences in different regions. This contrast difference is mainly caused by the different diffraction and scattering effects of light on different parts of the object to be measured 160. The dark-field signal light not only includes diffracted light, but also includes scattered light formed by the scattering of light by different parts of the object to be measured 160, etc. These light signals are captured by the dark-field camera 50 and converted into observable images or data, thereby realizing the detection and analysis of the internal structure and defects of the object to be measured 160.

[0043] In practical applications, the different positions of the bright-field optical axis and the dark-field optical axis in the embodiments of the present application can be: the bright-field optical axis and the dark-field optical axis can both have offsets relative to the system optical axis; or one of the bright-field optical axis and the dark-field optical axis is in the same position as the system optical axis while the other has a certain offset from the system optical axis, and no specific limitation is made here. Among them, the direction of the optical axis offset in the present application is perpendicular to the system optical axis.

[0044] In addition, in order to reduce the interference of external vibrations during the optical detection process on the bright and dark field optical detection device, the bright and dark field optical detection device should be isolated from the moving platform, where the moving platform refers to any type of optical platform. At the same time, in order to further reduce the influence of the jitter of the moving platform on the imaging of the bright-field camera 60 and the dark-field camera 50, in the embodiments of the present application, the connection line between the optical centers of the bright-field camera 60 and the dark-field camera 50 is parallel to the plane where the moving platform is located, or the connection line between the optical centers of the bright-field camera 60 and the dark-field camera 50 is parallel to the moving platform.

[0045] It should be noted that the guiding of light or the light beam by any of the foregoing and following optical devices in the present application can refer to any optical processing such as transmission, reflection, or refraction of light or the light beam through the any optical device to achieve the required technical effects, and no limitation is made here.

[0046] Different from the design of existing bright-field and dark-field optical detection devices, in the embodiments of the present application, the bright-field optical axis and the dark-field optical axis do not coincide. Therefore, the bright-field light beam can pass through the first optical component 30 along the bright-field optical axis to reach the object to be measured 160, and the formed bright-field signal light continues to pass through the first optical component 30 along the bright-field optical axis to reach the second optical component 40; the formed dark-field signal light can pass through the first optical component 30 along the dark-field optical axis to reach the second optical component 40; finally, after the dark-field signal light and the bright-field signal light are respectively incident on the second optical component 40, the second optical component 40 can respectively make the bright-field signal light reach the bright-field camera 60 and make the dark-field signal light reach the dark-field camera 50, where the transmission paths of the bright-field signal light and the dark-field signal light do not coincide in space. Therefore, the bright-field and dark-field optical detection device of the present application places the bright-field and the dark-field in the same optical system through a clever optical path design, ensuring that there is no interference between the bright-field and the dark-field. Allowing simultaneous bright-field detection and dark-field detection can effectively improve the detection efficiency of the bright-field and dark-field detection device.

[0047] Based on the foregoing embodiments, in some specific implementation manners, the second optical component 40 may be a beam splitting prism including at least two beam splitting surfaces (including the first beam splitting surface and the second beam splitting surface) (such as Figure 1 , 2 shown as 40 in

[0048] ), and each beam splitting surface is respectively used to reflect or transmit any signal light (bright-field signal light or dark-field signal light) to the corresponding camera. If it is the bright-field signal light, the corresponding camera is the bright-field camera 60; if it is the dark-field signal light, the corresponding camera is the dark-field camera 50. That is, the first beam splitting surface can be used to process the bright-field signal light or the dark-field signal light, and the second beam splitting surface can also be used to process the bright-field signal light or the dark-field signal light, as long as the signal lights processed by the first beam splitting surface and the second beam splitting surface are different. In practical applications, considering the ease of shape processing, the beam splitting prism may be an isosceles right triangle beam splitting prism, where the vertex of the isosceles right triangle coincides with the optical axis. Alternatively, the beam splitting component for controlling different signal lights to reach the corresponding cameras may further include at least two reflectors (such as the first reflector and the second reflector), and each reflector is used to reflect any signal light (bright-field signal light or dark-field signal light) to the corresponding camera. In other words, the two reflectors in the embodiments of the present application respectively replace the two beam splitting surfaces of the beam splitting prism and are used to reflect the signal lights to the corresponding cameras respectively. That is, the first reflector can be used to process the bright-field signal light or the dark-field signal light, and the second reflector can also be used to process the bright-field signal light or the dark-field signal light, as long as the signal lights processed by the first reflector and the second reflector are different.

[0049] Due to the requirements of dark-field detection, the dark-field light beam needs to irradiate the object to be measured 160 at a specific angle. If there is only a single light source, i.e., the dark-field light source 20, there will be a shadow on the side of the object to be measured 160 away from the dark-field light source 20 as it cannot be irradiated by the dark-field light source 20. In some other specific implementation manners, in order to ensure that the dark-field light source 20 can irradiate the object to be measured 160 evenly, the dark-field light source 20 may specifically include a plurality of dark-field light-emitting components such as the first dark-field light-emitting component 2110 and the second dark-field light-emitting component 2220. The plurality of dark-field light-emitting components such as the first dark-field light-emitting component 2110 and the second dark-field light-emitting component 2220 are symmetrically arranged about a preset optical axis in space. After the first dark-field light-emitting component 2110 and the second dark-field light-emitting component 2220 irradiate the same position of the object to be measured 160, at least part of the diffracted light and at least part of the scattered light generated constitute the dark-field signal light, and the dark-field signal light will be transmitted along the preset optical axis. Among them, the preset optical axis is the optical axis of the dark-field signal light and the optical axis of the dark-field light beam.

[0050] In some specific implementation manners, when the camera target surface or the imaging field of view is relatively fixed, in order to make full use of the limited imaging field of view in the bright-field camera and the dark-field camera, the optical axis of the bright-field signal light and the optical axis of the dark-field signal light can be symmetrically arranged about the system optical axis of the bright-field and dark-field optical detection device, and the interval between the optical axis of the bright-field signal light and the optical axis of the dark-field signal light is 0 to 2 millimeters.

[0051] For easy understanding, the components that the bright-field and dark-field optical detection device may further include in practical applications will be specifically described below. Please refer to Figure 2 Another bright-field and dark-field optical detection device disclosed in the embodiments of the present application is similar to the foregoing embodiments, except that it further includes a filtering component 70 for filtering the light in the target wavelength band from the bright-field light beam emitted from the bright-field light source 10 and enabling the bright-field light beam processed by the filtering component 70 to reach the first optical component 30. The target wavelength band includes the wavelength band where the background color of the object to be measured 160 is located. The filtering component 70 may include a filter of one color or may include a plurality of different colors of switchable filters. By switching the filters, the reflectivity of the background of the object to be measured 160 can be reduced, and the defect contrast can be improved to highlight the defects. For example, if the background color of the object to be measured 160 is red, the filter is preferably a color different from the red wavelength band, such as blue, green, or yellow.

[0052] Furthermore, the bright-field and dark-field optical detection device disclosed in the embodiments of the present application further includes: an objective lens 90, configured to receive the bright-field signal light and the dark-field signal light generated on the surface of the object to be measured 160, and emit the light after optical imaging magnification to the second optical component 40; an autofocus component 80, configured to emit a detection beam, measure the defocus amount of the object to be measured 160 relative to the objective lens 90 based on the detection beam, and assist the objective lens 90 to focus on the object to be measured 160. Wherein, the optical axis of the detection beam coincides with the system optical axis of the bright-field and dark-field optical imaging system of the present application.

[0053] Specifically, the autofocus component 80 is configured to assist the objective lens 90 to focus on the object to be measured 160 by emitting the detection beam. At the same time, in order to avoid interference of the detection beam on the signal light, the autofocus component 80 of the embodiments of the present application may include an autofocus module 801 and a third optical component 802. Wherein, the third optical component 802 reflects the detection beam to the object to be measured 160, and transmits the bright-field signal light and the dark-field signal light to the first optical component 30, so that the bright-field signal light and the dark-field signal light reach the corresponding cameras through the second optical component 40 respectively. Wherein, the third reflecting component may be a dichroic mirror, and the dichroic mirror is configured to reflect the light in the wavelength band where the detection beam is located and transmit the light in the wavelength band where the signal light is located. The objective lens 90 has a specific magnification, and at least one objective lens 90 may be disposed on the nose wheel 150 and the objective lens 90 is switched through the nose wheel 150 to implement bright-field and dark-field detection with different magnifications. Generally, in order to better distinguish the bright-field beam, the detection beam, and the dark-field beam incident on the object to be measured 160, the three may be implemented with light in different wavelength bands respectively.

[0054] Furthermore, the bright-field and dark-field optical detection device disclosed in the embodiments of the present application further includes: a spatial filtering component 100, configured to adjust the angular spectral frequency of the illumination beam incident on the object to be measured 160, and the spatial filtering component 100 is conjugate to the aperture stop of the objective lens 90. By controlling the distribution of the spatial wave filtering component (such as a spatial wave filter) in the embodiments of the present application, the angular spectral frequency of the bright-field illumination can be adjusted to implement illumination with multiple angular spectral frequencies, reduce the brightness of the background pattern of the object to be measured 160, and improve the contrast of the surface defects of the object to be measured 160 to highlight the defects.

[0055] In addition to the above components, in practical applications, the bright-field and dark-field optical detection device disclosed in the embodiments of the present application further includes, for example Figure 2The slit 140 shown in the figure (such as the etched slit 140 with sharp edges and no burrs), the steering assembly 130, the illumination tube lens 110, and the imaging tube lens 120, where the slit 140 is used to make the bright-field light spot in the shape of the slit 140; the steering assembly 130 can be arranged on the optical reference plane (configured as required) so that the bright-field light beam emitted from the bright-field light source 10 reaches the direction parallel to the moving platform after being deflected, and reaches the first optical component 30, reducing the influence of the vibration of the moving platform on the bright-field illumination optical path; the illumination tube lens 110 is used to focus the bright-field light beam to the bright-field illumination point of the object to be measured 160 through the objective lens 90, or to make the bright-field light beam accurately reach the objective lens 90 and accurately pass through the objective lens 90 to irradiate the object to be measured 160. The imaging tube lens 120 is used to receive the bright-field signal light and the dark-field signal light, and focus the bright-field signal light to the bright-field camera 60 through the second optical component 40, and focus the dark-field signal light to the dark-field camera 50 through the second optical component 40, or to make the signal light accurately reach the target surface of the corresponding camera through the objective lens 90. In some specific implementation manners, the foregoing first optical component 30 can be at a 45-degree angle to the system optical axis, so that the imaging tube lens 120 can be placed parallel to the moving platform on the optical reference plane, reducing the influence of the vibration of the moving platform on the imaging optical path.

[0056] In some specific implementation scenarios, the detection beam of the autofocus component 80 uses light in the red wavelength band, such as 650 - 700 nm. The incident bright-field light beam and dark-field light beam on the object to be measured 160 can be in the wavelength band of 400 - 650 nm; the third optical component 802 reflects light with a wavelength above 650 nm and transmits light with a wavelength below 650 nm. The transmittance of the first optical component 30 is in the range of 0 - 50%, and the reflectance of the first optical component 30 is in the range of 50% - 90%.

[0057] Based on the foregoing embodiments, it can be understood that the bright and dark field optical detection device of the present application can be used to independently perform the initial inspection of bright and dark field detection and the re-inspection of bright and dark field detection. If the bright and dark field optical detection device of the present application is applied to the re-inspection of the object to be measured 160, the magnification of the objective lens 90 in the bright and dark field optical detection device should be greater than the magnification of the objective lens 90 used for the initial inspection of the object to be measured 160 to ensure the accuracy of the re-inspection. In the embodiments of the present application, when the magnification of the objective lens 90 in the bright and dark field optical detection device is greater than the magnification of the objective lens 90 used for the initial inspection of the object to be measured 160, only by moving the object to be measured 160 to the position where the object to be measured 160 needs to be placed in the bright and dark field optical detection device of the present application through a conveyor belt or a manipulator, the re-inspection can be performed through the objective lens 90 with a higher magnification, improving the accuracy of the re-inspection.

[0058] In addition, in order to improve the imaging efficiency and more accurately detect the object to be measured 160, in the embodiments of the present application, the bright-field optical axis and the dark-field optical axis are symmetric about the system optical axis of the bright and dark field optical detection device. Moreover, in order to improve the accuracy of bright and dark field detection, the embodiments of the present application expect that the distance between the bright-field spot where the bright-field beam irradiates the object to be measured 160 and the dark-field spot where the dark-field beam irradiates the object to be measured 160 is as close as possible. However, due to aberration and stray light, there will be a halo or a diffused spot around both the bright-field spot and the dark-field spot. If the bright and dark field interval is 0, it is necessary to pay a great cost to make the surface of the optical element clean enough without defects, and there is no aberration in the illumination optical path (the bright-field illumination optical path through which the bright-field beam passes and the dark-field illumination optical path through which the dark-field beam passes). Therefore, generally, a certain distance is required to be maintained between the bright-field spot and the dark-field spot, that is, the bright and dark field interval between the bright-field optical axis and the dark-field optical axis should be greater than 0. In fact, according to actual repeated experiments, on the premise of avoiding mutual interference between the bright and dark fields and ensuring the accuracy of bright and dark field detection as much as possible, the embodiments of the present application expect that the bright and dark field interval between the bright-field optical axis and the dark-field optical axis can be 0 to 2 millimeters.

[0059] On the basis of the foregoing embodiments, in a specific implementation manner, considering the engineering difficulty and cost, a reasonable distance needs to be given for the bright and dark field interval, which not only ensures that the bright and dark fields do not interfere with each other, but also does not make the bright and dark fields too far apart, resulting in too large a diameter of the imaging field of view. Please refer to Figure 3 , generally, in order to ensure the imaging quality and thus ensure the bright and dark field detection quality, the target sizes (including the target length and the target width) of the bright-field camera 60 and the dark-field camera 50 are usually the same. Specifically, the diameter of the imaging field of view of the bright and dark field optical detection device is calculated according to the following formula:

[0060]

[0061] where D is the diameter of the imaging field of view of the bright and dark field optical detection device, l is the target length of the camera, w is the target width of the camera, and d is the bright and dark field interval between the bright-field optical axis and the dark-field optical axis, and the target lengths and target widths of the bright-field camera 60 and the dark-field camera 50 are the same.

[0062] Specifically, please refer to Figure 3 , since the target sizes of the bright-field camera 60 and the dark-field camera 50 are the same, and the bright-field optical axis and the dark-field optical axis are symmetric about the system optical axis, that is, the bright-field camera 60 and the dark-field camera 50 are symmetric about the diameter of the imaging field of view. Components such as Figure 3 the triangle shown in

[0063] The above content is an explanation of the present application in combination with specific embodiments, and it cannot be determined that the specific implementation of the present application is limited to these embodiments. For those of ordinary skill in the technical field to which the present application belongs, without departing from the concept of the present application, several transformations and substitutions can still be made, and in this case, it should be regarded as belonging to the protection scope of the present application.

Claims

1. A bright and dark field optical detection device, characterized in that, Comprising: A bright-field light source for emitting a bright-field light beam and causing the bright-field light beam to reach a first optical component; A dark-field light source for emitting a dark-field light beam that reaches the object to be measured; The first optical component for guiding the bright-field light beam to irradiate the object to be measured, receiving the bright-field signal light generated on the surface of the object to be measured by the bright-field light beam and guiding it to a second optical component, and receiving the dark-field signal light generated on the surface of the object to be measured by the dark-field light beam and guiding it to the second optical component; the transmission paths of the bright-field signal light and the dark-field signal light do not coincide spatially; The second optical component for guiding the bright-field signal light to reach a bright-field camera and guiding the dark-field signal light to reach a dark-field camera.

2. The bright and dark field optical detection device according to claim 1, wherein The second optical component includes a beam-splitting prism, a first beam-splitting surface of the beam-splitting prism for receiving the bright-field signal light and reflecting or transmitting it to the bright-field camera, and a second beam-splitting surface of the beam-splitting prism for receiving the dark-field signal light and reflecting or transmitting it to the dark-field camera; Or, The second optical component includes a first mirror and a second mirror, the first mirror for receiving the bright-field signal light and reflecting it to the bright-field camera, and the second mirror for receiving the dark-field signal light and reflecting it to the dark-field camera.

3. The bright and dark field optical detection device according to claim 1, wherein The dark-field light source includes a plurality of dark-field light-emitting components, each of the dark-field light-emitting components being symmetrically arranged about a preset optical axis of space, and the irradiation light beams of each of the dark-field light-emitting components forming the dark-field signal light on the surface of the object to be measured, and the dark-field signal light being transmitted along the preset optical axis.

4. The bright and dark field optical detection device according to claim 1, characterized in that, The optical axis of the bright-field signal light is symmetric about the system optical axis of the bright-field and dark-field optical detection device with the optical axis of the dark-field signal light, and the interval between the optical axis of the bright-field signal light and the optical axis of the dark-field signal light is 0 to 2 millimeters.

5. The bright and dark field optical detection device according to claim 1, wherein Further comprising: A filtering component for filtering the light in a target wavelength band from the bright-field light beam emitted from the bright-field light source and causing the bright-field light beam processed by the filtering component to reach the first optical component, the target wavelength band including the wavelength band where the background color of the object to be measured is located.

6. The bright and dark field optical detection device according to claim 1, wherein, Further comprising: An objective lens for receiving the bright-field signal light and the dark-field signal light generated on the surface of the object to be measured and emitting them to the second optical component after being optically imaged and magnified; An autofocus component for emitting a detection light beam, measuring the defocus amount of the object to be measured relative to the objective lens based on the detection light beam, and assisting the objective lens to focus on the object to be measured.

7. The bright and dark field optical detection device according to claim 6, wherein Further comprising: A spatial filtering component for adjusting the angular spectral frequency of the illumination light beam irradiated on the object to be measured, the spatial filtering component being conjugate to the aperture stop of the objective lens.

8. The bright and dark field optical detection device according to claim 6, characterized in that, Applied to the re-inspection of the object to be measured, the magnification of the objective lens is greater than the magnification of the objective lens used for the initial inspection of the object to be measured.

9. The bright and dark field optical detection device according to claim 1, wherein Further comprising: A turning component for causing the illumination light beam emitted from the bright-field light source to reach the first optical component after being turned.

10. The bright and dark field optical detection device according to claim 1, wherein The diameter of the imaging field of view of the bright and dark field optical detection device is where D is the diameter of the imaging field of view of the bright and dark field optical detection device, l is the length of the camera target surface, w is the width of the camera target surface, and d is the bright and dark field interval between the bright field optical axis and the dark field optical axis. The lengths and widths of the camera target surfaces of the bright field camera and the dark field camera are the same.

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