Optical detection device

Abstract

An optical detection device, comprising an objective lens, a bright field illumination unit and a dark field illumination unit. The objective lens is provided with a bright field light channel and a dark field light channel. The bright field illumination unit comprises a bright field beam splitting unit and a bright field light source for providing a bright field incident light beam, wherein the bright field incident light beam is reflected by the bright field beam splitting unit and then enters the bright field light channel. The dark field illumination unit comprises a dark field light source for emitting a dark field incident light beam, a prism module and a dark field beam splitting unit; the prism module and the dark field beam splitting unit are sequentially arranged in the transmission direction of the dark field incident light beam; the prism module is used for converting the dark field incident light beam into a circular light beam, wherein the circular light beam is reflected by the dark field beam splitting unit and then enters the dark field light channel; and the dark field beam splitting unit comprises a circular beam splitter and an aperture formed at the center of the circular beam splitter, wherein the aperture is located on the transmission path of the bright field incident light beam. The present invention more conveniently realizes switching between bright field detection and dark field detection, thereby improving the detection efficiency.

Description

Optical inspection equipment

[0001] The present invention is based on and claims the priority of Chinese patent application with application number 202410135202.0 and application date January 31, 2024. The entire contents of the above patent application are hereby incorporated by reference into the present invention. Technical Field

[0002] The present invention relates to the field of microscopic detection, in particular to optical detection equipment. Background Art

[0003] Defect detection generally refers to the detection of surface defects on a sample. Defects include, but are not limited to, foreign contaminants, abnormal protrusions on the sample surface, scratches on the sample surface, grooves on the sample surface, and deformation of specific surface patterns. Defect detection is in high demand across various industrial production processes, such as integrated circuits, display panels, glass, and metal products. In particular, wafer surface defect detection is an essential and critical process in integrated circuit production. Accurately detecting defective wafers can significantly improve product yield.

[0004] To more comprehensively inspect wafers, existing optical inspection equipment performs both brightfield and darkfield inspections. Darkfield microscopy is the primary method for detecting surface defects in darkfield environments. Darkfield microscopy is a simple, label-free, and highly real-time inspection method. It captures only scattered light from the object being inspected, ignoring illumination reflected or transmitted from the sample surface. This creates a clear contrast between the dark background and the bright target signal in the inspection image.

[0005] During the wafer inspection process, when switching from a bright field environment to a dark field environment, or from a dark field environment to a bright field environment, the wafer needs to be moved to a different inspection station, which complicates the inspection process and reduces the inspection efficiency.

[0006] The reference to any prior art in the specification is not an acknowledgement or suggestion that the prior art forms part of the common general knowledge in any jurisdiction, or that it could reasonably be expected that the person skilled in the art would understand, consider relevant and / or combine with other prior art. Summary of the Invention

[0007] The purpose of the present invention is to provide an optical detection device to solve the shortcomings of the existing technology. It can prevent mutual interference between the various components of bright field imaging and the various components of dark field imaging, and bright field imaging and dark field imaging can achieve independent imaging respectively; in the process of switching between bright field detection and dark field detection, only the light source needs to be adjusted, and the corresponding light source can be controlled as needed, which makes it more convenient to switch between bright field detection and dark field detection and improves detection efficiency.

[0008] The optical detection device provided by the present invention includes:

[0009] An objective lens having a bright field light channel and a dark field light channel;

[0010] A bright field illumination unit, comprising a bright field spectroscopic unit and a bright field light source for providing a bright field incident light beam to the object to be measured, wherein the bright field incident light beam enters the bright field light channel after being reflected by the bright field spectroscopic unit;

[0011] A dark field illumination unit includes a dark field light source for emitting a dark field incident light beam toward the object to be measured, a prism module, and a dark field spectrometer; the prism module and the dark field spectrometer are sequentially arranged along the transmission direction of the dark field incident light beam; the prism module is used to transform the dark field incident light beam emitted by the dark field light source into an annular light beam, which enters the dark field light channel after being reflected by the dark field spectrometer;

[0012] The dark field spectrometer unit includes an annular spectrometer and a through hole arranged at the center of the annular spectrometer, and the through hole is located on the transmission path of the bright field incident light beam.

[0013] Furthermore, the prism module includes a concave axle and a convex axle arranged at the center of the concave axle, and the center of the convex axle is opposite to the perforation position at the center of the annular beam splitter;

[0014] The dark field incident light beam is reflected by the convex axicon and then reaches the concave axicon, and the concave axicon reflects the dark field incident light beam to the annular beam splitter.

[0015] Furthermore, the convex conic mirror can be moved and adjusted along the axial direction of the concave conic mirror.

[0016] Furthermore, the prism module and the dark field light source are located on opposite sides of the annular beam splitter;

[0017] The annular beam splitter has a dark field reflecting surface, and the bright field beam splitting unit has a bright field reflecting surface. The orientation direction of the dark field reflecting surface is perpendicular to the orientation direction of the bright field reflecting surface.

[0018] Furthermore, the prism module includes a single-sided concave lens and a single-sided convex lens sequentially arranged along the transmission path of the dark field incident light beam, wherein the single-sided concave lens is concavely arranged in a direction away from the single-sided convex lens; and the single-sided convex lens is convexly arranged in the direction where the single-sided concave lens is located;

[0019] The dark field incident light beam is refracted by the single-sided concave lens and the single-sided convex lens in sequence to form an annular light beam that is irradiated on the annular beam splitter.

[0020] Furthermore, the dark field incident light beam is irradiated onto the single concave lens along the axial direction of the single concave lens.

[0021] Furthermore, the distance between the single-sided concave lens and the single-sided convex lens is adjustable.

[0022] Furthermore, a focusing lens is provided between the single-sided convex lens and the annular beam splitter.

[0023] Furthermore, the prism module and the dark field light source are located on the same side of the annular beam splitter;

[0024] The annular beam splitter has a dark field reflecting surface, and the bright field beam splitting unit has a bright field reflecting surface. The dark field reflecting surface faces the same direction as the bright field reflecting surface.

[0025] Furthermore, the pit formed by the middle concave setting of the single-sided concave lens is cone-shaped as a whole; the protrusion formed by the outward convex extension of the single-sided convex lens is cone-shaped as a whole.

[0026] Furthermore, the concave pit formed by the concave arrangement of the single-sided concave lens matches the convex shape formed by the convex extension of the single-sided convex lens, and both the concave pit and the convex shape are conical.

[0027] Furthermore, the optical detection device also includes an image acquisition unit, which is used to receive the outgoing light beam reflected by the object to be tested and finally form an image of the object to be tested; the outgoing light beam enters the image acquisition unit after being transmitted by the bright field spectrometer.

[0028] Furthermore, the bright field spectroscopic unit is a semi-transparent and semi-reflective mirror.

[0029] Furthermore, the optical detection device also has a laser and a laser beam splitter matched with the laser. The focusing laser emitted by the laser is reflected by the laser beam splitter and then enters the objective lens.

[0030] Furthermore, the optical detection device also has an objective lens switching platform, on which a plurality of objective lenses are arranged. The objective lens switching platform can realize switching of different objective lenses, thereby realizing imaging of the sample at different magnifications.

[0031] Compared with the prior art, the present invention can generate an annular light beam through the setting of the prism module. After being reflected by the annular beam splitter, the annular light beam is reflected into the dark field light channel of the objective lens to form dark field detection light irradiated on the object to be tested; since a perforation is provided at the center position of the annular beam splitter, and the perforation is located on the transmission path of the bright field incident light beam, there is no mutual interference between the various components of the bright field imaging and the various components of the dark field imaging, and the bright field imaging and the dark field imaging can realize independent imaging respectively; in the process of switching between bright field detection and dark field detection during the optical detection process, only the adjustment of the light source needs to be completed, and the corresponding light source can be controlled as needed, which makes it more convenient to realize the switching between bright field detection and dark field detection, thereby improving the detection efficiency.

[0032] As used herein, the term "comprise" and variations of the term, such as "comprises," "comprised," "comprising," "including," and "containing" do not exclude other features, components, elements, or steps unless the context clearly requires otherwise. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG1 is a schematic structural diagram of an optical detection device disclosed in Example 1 of the present invention;

[0034] FIG2 is a schematic diagram of the principle of the optical detection device disclosed in Example 1 of the present invention;

[0035] FIG3 is a schematic structural diagram of an optical detection device disclosed in Example 2 of the present invention;

[0036] FIG4 is a schematic diagram of the principle of the optical detection device disclosed in Example 2 of the present invention;

[0037] Explanation of the accompanying drawings: 1-objective lens, 11-bright field light channel, 12-dark field light channel, 2-bright field illumination unit, 21-bright field spectroscopic unit, 22-bright field light source, 3-dark field illumination unit, 31-dark field light source, 32-prism module, 321-concave cone mirror, 322-convex cone mirror, 323-single-sided concave lens, 324-single-sided convex lens, 325-focusing lens, 33-dark field spectroscopic unit, 331-annular spectroscopic mirror, 332-perforation, 4-image acquisition unit, 5-objective lens switching platform, 6-laser, 7-laser spectroscopic element. DETAILED DESCRIPTION

[0038] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0039] As shown in FIG1 to FIG4 , an optical detection device according to an embodiment of the present invention includes an objective lens 1 , a bright field illumination unit 2 and a dark field illumination unit 3 .

[0040] Objective lens 1 is used to focus on the object to be tested, so that the object to be tested can be observed through the eyepiece or image acquisition unit. The object to be tested can be, for example, a wafer. It is understood that to facilitate the placement of the object to be tested, the optical inspection device also has an object stage, which is used to position and support the object to be tested, and the objective lens 1 is located above the object stage. In conjunction with the brightfield illumination unit 2, objective lens 1 can produce brightfield imaging of the object to be tested. In conjunction with the darkfield illumination unit 3, objective lens 1 can produce darkfield imaging of the object to be tested.

[0041] The brightfield illumination unit 2 emits a brightfield incident light beam toward the object under test through the objective lens 1, and the darkfield illumination unit 3 emits a darkfield incident light beam toward the object under test through the objective lens 1. To allow the brightfield incident light beam to pass through the objective lens 1, the objective lens 1 of this embodiment has a brightfield light channel 11, through which the brightfield incident light beam is irradiated onto the object under test. To allow the darkfield incident light beam to pass through the objective lens 1, the objective lens 1 of this embodiment has a darkfield light channel 12, through which the darkfield incident light beam is irradiated onto the object under test.

[0042] Compared to the method of using an oblique dark-field light source, in which the dark-field light source does not pass through the objective lens but directly illuminates the object to be measured, the objective lens 1 of this embodiment can pass through both the bright-field incident light beam and the dark-field incident light beam at the same time, which can save more space in terms of structure and avoid occupying the lateral space of the microscopic detection device.

[0043] The brightfield illumination unit 2 includes a brightfield spectrometer 21 and a brightfield light source 22 that provides a brightfield incident light beam to the object under test. The brightfield incident light beam is reflected by the brightfield spectrometer 21 and enters the brightfield light channel 11. The brightfield incident light beam passes through the brightfield light channel 11 and illuminates the object under test. After exiting the brightfield light channel 11, the brightfield incident light beam illuminates the object under test on the stage in a direction approximately perpendicular to the plane of the stage.

[0044] The dark-field illumination unit 3 includes a dark-field light source 31 that emits a dark-field incident light beam toward the object under test, a prism module 32, and a dark-field spectrometer 33. The prism module 32 and the dark-field spectrometer 33 are arranged sequentially along the transmission direction of the dark-field incident light beam. The prism module 32 is used to transform the dark-field incident light beam emitted by the dark-field light source 31 into an annular beam. After being reflected by the dark-field spectrometer 33, the annular beam enters the dark-field light channel 12. After passing through the dark-field light channel 12, the annular beam illuminates the object under test at an oblique direction. After exiting the dark-field light channel 12, the dark-field incident light beam illuminates the object under test in a direction that intersects the plane of the stage at an angle less than 90 degrees.

[0045] Since the light entering the dark-field light channel 12 is an annular beam, in order to better adapt to the annular beam, the dark-field light channel 12 is also arranged in an annular shape as a whole. The objective lens 1 is generally cylindrical as a whole. The bright-field light channel 11 extends along the direction of the central axis of the objective lens 1. The dark-field light channel 12 is annular as a whole and is arranged around the bright-field light channel 11, and the ring formed by the dark-field light channel 12 is coaxial with the bright-field light channel 11.

[0046] The bright field incident light beam is irradiated on the object to be measured after passing through the bright field light channel 11 of the objective lens 1. The bright field reflected light beam formed after being reflected by the object to be measured returns along the bright field light channel 11 and is finally imaged at the eyepiece position or enters the image acquisition unit and is captured by the image acquisition unit.

[0047] After passing through the dark field light channel 12, the dark field incident light beam is irradiated on the object to be measured and produces reflection and diffuse reflection. Among them, the dark field reflected light beam is emitted from the outside of the objective lens 1 to the outside of the objective lens 1, and part of the diffusely reflected light beam enters the bright field light channel 11, and is finally imaged at the eyepiece position or enters the image acquisition unit and is captured by the image acquisition unit.

[0048] The dark field spectrometer unit 33 includes an annular spectrometer 331 and a through hole 332 provided at the center of the annular spectrometer 331 . The through hole 332 is located on the transmission path of the bright field incident light beam.

[0049] In the existing technology, during the dark field imaging process, the center position of part of the light source is generally blocked by a shielding sheet to diffract the point light source emitted by the lighting unit into a ring-shaped light beam. Since part of the light is blocked, in order to improve the detection effect of the ring-shaped light beam, it is generally necessary to increase the intensity of the lighting unit when switching to dark field detection. During the entire switching process, not only the equipment needs to be adjusted, but also the light intensity needs to be adjusted, resulting in low switching efficiency.

[0050] In this embodiment, the prism module 32 is configured to generate an annular light beam, and the annular beam splitter 331 is capable of reflecting the annular light beam generated by the prism module 32. After reflection, the annular light beam enters the dark field light channel 12 of the objective lens 1 to form a dark field detection light irradiated on the object to be tested.

[0051] Since a perforation 332 is provided at the center position of the annular beam splitter 331, and the perforation 332 is located on the transmission path of the bright field incident light beam, there is no mutual interference between the various components of bright field imaging and the various components of dark field imaging, and bright field imaging and dark field imaging can realize independent imaging respectively. With such a structural setting, during the process of switching between bright field detection and dark field detection during the optical detection process, it is only necessary to adjust the light source, and the corresponding light source can be controlled as needed, which makes switching more convenient and improves the detection efficiency.

[0052] In a specific embodiment, the brightfield light source 22 and the darkfield light source 31 can be two independent light sources, which are independently controlled. When performing brightfield detection, the brightfield light source 22 is turned on and the darkfield light source 31 is turned off. When performing darkfield detection, the darkfield light source 31 is turned on and the brightfield light source 22 is turned on.

[0053] In another embodiment, the brightfield light source 22 and the darkfield light source 31 can be sourced from the same light source. Specifically, a light source controller can be provided along the transmission path of the light source. During brightfield detection, the light source controller directs the light beam emitted by the light source onto the brightfield detection path to form a brightfield incident light beam. During darkfield detection, the light source controller directs the light beam emitted by the light source onto the darkfield detection path to form a darkfield incident light beam. It should be noted that the specific structure of the light source controller is not further defined herein; its primary purpose is to change the transmission path of the light source.

[0054] Of course, one light source can also be used to provide illumination for both bright field detection and dark field detection. By adjusting the proportion of illumination on the bright field detection route and the dark field detection route, the effect of simultaneous imaging of the bright field and dark field can be achieved, and the visual effect of stacking bright field imaging and dark field imaging can be obtained.

[0055] Forming an annular beam is crucial in dark-field imaging. Conventional techniques typically block the center of a point light source to diffract it, resulting in inefficient light source utilization. In this embodiment, the prism module 32 is configured to generate an annular beam while minimizing light source loss, thereby enhancing dark-field imaging.

[0056] The specific prism module 32 includes at least the following two methods:

[0057] For the first prism module, as shown in Figure 1-2, the prism module 32 includes a concave cone 321 and a convex cone 322 arranged at the center of the concave cone 321, and the center of the convex cone 322 corresponds to the position of the through hole 332 at the center of the annular beam splitter 331.

[0058] The dark field incident light beam is reflected by the convex conical mirror 322 and then reaches the concave conical mirror 321 . The concave conical mirror 321 reflects the dark field incident light beam to the annular beam splitter 331 .

[0059] The dark field incident light beam emitted from the dark field light source 31 passes through the through hole 332 and is incident on the convex conical mirror 322, and is reflected by the convex conical mirror 322 to the concave conical mirror 321. The concave conical mirror 321 is opposite to the convex conical mirror 322 and the concave direction of the concave conical mirror 321 is opposite to the convex direction of the convex conical mirror 322, so that the reflected light beam is transmitted along the convex direction of the convex conical mirror 322.

[0060] In this embodiment, the convex conical mirror 322 is generally conical and has an axial direction. The light beam emitted from the dark field light source 31 is incident on the convex conical mirror 322 along the axial direction.

[0061] In this embodiment, the prism module 32 and the dark field light source 31 are located on opposite sides of the annular beam splitter 331; the annular beam splitter 331 has a dark field reflecting surface, and the bright field beam splitting unit 21 has a bright field reflecting surface, and the direction of the dark field reflecting surface is perpendicular to the direction of the bright field reflecting surface.

[0062] The angle between the plane where the bright field reflecting surface is located and the horizontal plane is equal to the angle between the plane where the dark field reflecting surface is located and the horizontal plane; the extension direction of the normal line of the bright field reflecting surface and the extension direction of the normal line of the plane where the dark field reflecting surface is located are perpendicular to each other.

[0063] The plane where the bright field reflective surface is located is tilted at 45 degrees relative to the horizontal plane as a whole, and the plane where the dark field reflective surface is located is also tilted at 45 degrees relative to the horizontal plane as a whole.

[0064] Furthermore, the convex conical mirror 322 can be moved and adjusted along the axial direction of the concave conical mirror 321. The convex conical mirror 322 approaches or moves away from the annular beam splitter 331 along the axial direction of the concave conical mirror 321. When the convex conical mirror 322 moves toward the annular beam splitter 331, a portion of the concave conical mirror 321 no longer corresponds to the convex conical mirror 322. The portion of the concave conical mirror 321 that does not correspond to the convex conical mirror 322 cannot receive the reflected light from the convex conical mirror 322. As a result, only the portion of the concave conical mirror 321 that corresponds to the convex conical mirror 322 receives the reflected light from the convex conical mirror 322, thereby narrowing the size of the formed annular beam.

[0065] When convex axicon 322 moves away from annular beam splitter 331, it completely aligns with concave axicon 321, and the resulting annular beam is relatively larger. As can be seen from the above, the width of the resulting annular beam can be adjusted by controlling the axial movement of convex axicon 322 relative to concave axicon 321, thereby meeting different needs and improving adaptability.

[0066] For the second type of prism module, as shown in Figure 3-4, the prism module 32 includes a single-sided concave lens 323 and a single-sided convex lens 324 arranged in sequence along the transmission path of the dark field incident light beam. The single-sided concave lens 323 is concave in the direction away from the single-sided convex lens 324; the single-sided convex lens 324 is convex in the direction of the single-sided concave lens 323.

[0067] The dark field incident light beam is refracted by the single-sided concave lens 323 and the single-sided convex lens 324 in sequence to form an annular light beam that is irradiated on the annular beam splitter 331 .

[0068] The light is refracted by the single-sided concave lens 323 and the single-sided convex lens 324 to form an annular light beam. After the annular light beam is formed, it is reflected by the annular beam splitter 331 and then irradiated onto the object to be measured.

[0069] In this embodiment, the concave pit formed by the middle concave lens 323 is generally conical, specifically, it can be a cone. The protrusion formed by the outward protrusion of the single convex lens 324 is generally conical, specifically, the protrusion formed by the outward protrusion of the single convex lens 324 is conical.

[0070] In this embodiment, the concave pit formed by the concave arrangement of the single-sided concave lens 323 matches the convex shape formed by the convex extension of the single-sided convex lens 324.

[0071] To better form an annular beam, the dark field incident light beam emitted by the dark field light source 31 is irradiated onto the single concave lens 323 along the axial direction of the single concave lens 323. The dark field incident light beam is incident from the side of the single concave lens 323 facing away from the single convex lens 324, and after being refracted by the single concave lens 324, enters the single convex lens 324, and is further refracted by the single convex lens 324 to form an annular beam.

[0072] The distance between the single concave lens 323 and the single convex lens 324 is adjustable. By adjusting the distance between the single concave lens 323 and the single convex lens 324, the width of the annular light beam can be adjusted to meet different detection needs and improve adaptability.

[0073] Furthermore, the prism module 32 also includes a focusing lens 325, which is disposed between the single-sided convex lens 324 and the annular beam splitter 331. The focusing lens 325 is a double-sided convex lens, and further refraction by the focusing lens 325 can form a more regular annular beam, thereby better concentrating the light source energy and reducing light source loss.

[0074] The prism module 32 and the dark field light source 31 are located on the same side of the annular beam splitter 331; the annular beam splitter 331 has a dark field reflecting surface, and the bright field beam splitting unit 21 has a bright field reflecting surface, and the direction of the dark field reflecting surface is the same as the direction of the bright field reflecting surface.

[0075] The angle between the plane of the brightfield reflective surface and the horizontal plane is equal to the angle between the plane of the darkfield reflective surface and the horizontal plane; the plane of the brightfield reflective surface is inclined at 45° relative to the horizontal plane, and the plane of the darkfield reflective surface is also inclined at 45° relative to the horizontal plane. The normal direction of the brightfield reflective surface is parallel to the normal direction of the plane of the darkfield reflective surface.

[0076] The above-mentioned setting of the bright field reflecting surface and the dark field reflecting surface allows the outgoing light beam of the lighting units 2 and 3 to be incident on the reflecting surface in the horizontal direction, and after being reflected by the reflecting surface, it forms a reflected light beam entering the objective lens in the vertical direction, which makes the setting of the lighting units 2 and 3 more convenient.

[0077] Of course, in other embodiments, the angle between the plane where the brightfield reflective surface is located and the horizontal plane may be different from the angle between the plane where the darkfield reflective surface is located and the horizontal plane. The angle between the plane where the brightfield reflective surface is located and the horizontal plane can be adjusted as needed and does not have to be limited to 45°. When the angle between the plane where the brightfield reflective surface is located and the horizontal plane is adjusted, it is necessary to adjust the angle of the incident light beam impinging on the brightfield reflective surface accordingly, so that the incident light beam can form a light beam that is irradiated toward the objective lens 1 after being reflected by the brightfield reflective surface.

[0078] Correspondingly, the angle between the plane where the dark field reflective surface is located and the horizontal plane can also be set as needed. During adjustment, in order to ensure that the light beam reflected by the dark field reflective surface enters the objective lens 1 in the vertical direction, it is necessary to adjust the angle of the light beam emitted by the dark field lighting unit 3 to the dark field reflective surface accordingly.

[0079] It can be understood that the optical detection equipment also includes an image acquisition unit 4, which is used to receive the light beam reflected by the object to be tested and ultimately form an image of the object to be tested; the light beam reflected by the object to be tested enters the image acquisition unit 4 after being transmitted through the bright field spectrometer 21; in this embodiment, the image acquisition unit 4 is a camera.

[0080] Since the image acquisition unit 4 is located on the side of the bright field spectrometer unit 21 away from the objective lens 1, if the reflected light beam reflected by the object to be detected needs to enter the image acquisition unit 4 for imaging after passing through the objective lens 1, the reflected light beam needs to pass through the bright field spectrometer unit 21. At the same time, the bright field spectrometer unit 21 also plays the role of reflecting the bright field incident light beam to the objective lens 1. Therefore, in this embodiment, the bright field spectrometer unit 21 is a semi-transparent and semi-reflective mirror, which has a reflective surface that can reflect the incident light beam to the objective lens 1, and can allow the reflected light beam to pass through so that the reflected light beam is transmitted to the image acquisition unit 4.

[0081] It should be noted that two image acquisition units 4 can be set, and the two image acquisition units 4 are used to acquire bright field detection images and dark field detection images respectively. The two image acquisition units 4 can work in turn, or the image acquisition units 4 can be linked with the light source controller. When the light source emits a bright field incident light beam, the image acquisition unit 4 that acquires the bright field image works; when the light source emits a dark field incident light beam, the image acquisition unit 4 that acquires the dark field image works.

[0082] As shown in Figures 1 and 3, in order to enable the use of objective lenses with different magnifications, the optical detection equipment also has an objective lens switching platform 5, on which multiple objective lenses 1 are arranged. The objective lens switching platform can realize the switching of different objective lenses, thereby realizing imaging of samples at different magnifications.

[0083] Furthermore, in order to achieve automatic focusing, the optical detection device also has a laser 6 and a laser beam splitter 7 cooperating with the laser 6 . The focusing laser emitted by the laser 6 is reflected by the laser beam splitter 7 and enters the objective lens 1 .

[0084] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present invention, but the scope of implementation of the present invention is not limited to what is shown in the drawings. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which do not exceed the spirit covered by the description and drawings, should be within the scope of protection of the present invention.

Claims

1. An optical detection device, characterized in that: include: An objective lens having a bright field light channel and a dark field light channel; A bright field illumination unit, comprising a bright field spectroscopic unit and a bright field light source for providing a bright field incident light beam to the object to be measured, wherein the bright field incident light beam enters the bright field light channel after being reflected by the bright field spectroscopic unit; A dark field illumination unit includes a dark field light source for emitting a dark field incident light beam toward the object to be measured, a prism module, and a dark field spectrometer; the prism module and the dark field spectrometer are sequentially arranged along the transmission direction of the dark field incident light beam; the prism module is used to transform the dark field incident light beam emitted by the dark field light source into an annular light beam, which enters the dark field light channel after being reflected by the dark field spectrometer; The dark field spectrometer unit includes an annular spectrometer and a through hole arranged at the center of the annular spectrometer, and the through hole is located on the transmission path of the bright field incident light beam.

2. The optical detection device according to claim 1, characterized in that: The prism module includes a concave cone and a convex cone arranged at the center of the concave cone, wherein the center of the convex cone is opposite to the perforation position at the center of the annular beam splitter; The dark field incident light beam is reflected by the convex axicon and then reaches the concave axicon, and the concave axicon reflects the dark field incident light beam to the annular beam splitter.

3. The optical detection device according to claim 2, characterized in that: The convex conic mirror can be moved and adjusted along the axial direction of the concave conic mirror.

4. The optical detection device according to claim 2, characterized in that: The prism module and the dark field light source are located on opposite sides of the annular beam splitter; The annular beam splitter has a dark field reflecting surface, and the bright field beam splitting unit has a bright field reflecting surface. The orientation direction of the dark field reflecting surface is perpendicular to the orientation direction of the bright field reflecting surface.

5. The optical detection device according to claim 1, characterized in that: The prism module includes a single-sided concave lens and a single-sided convex lens arranged in sequence along the transmission path of the dark field incident light beam, wherein the single-sided concave lens is concavely arranged in a direction away from the single-sided convex lens; and the single-sided convex lens is convexly arranged in the direction where the single-sided concave lens is located; The dark field incident light beam is refracted by the single-sided concave lens and the single-sided convex lens in sequence to form an annular light beam that is irradiated on the annular beam splitter.

6. The optical detection device according to claim 5, characterized in that: The dark field incident light beam is irradiated onto the single concave lens along the axial direction of the single concave lens.

7. The optical detection device according to claim 6, characterized in that: The distance between the single-sided concave lens and the single-sided convex lens is adjustable.

8. The optical detection device according to claim 5, characterized in that: A focusing lens is further provided between the single-sided convex lens and the annular beam splitter.

9. The optical detection device according to claim 5, characterized in that: The prism module and the dark field light source are located on the same side of the annular beam splitter; The annular beam splitter has a dark field reflecting surface, and the bright field beam splitting unit has a bright field reflecting surface. The dark field reflecting surface faces the same direction as the bright field reflecting surface.

10. The optical detection device according to claim 5, characterized in that: The pit formed by the concave setting in the middle of the single-sided concave lens is cone-shaped as a whole; the bulge formed by the outward convex extension of the single-sided convex lens is cone-shaped as a whole.

11. The optical detection device according to claim 10, characterized in that: The concave pit formed by the concave setting of the single-sided concave lens is matched with the convex shape formed by the convex extension of the single-sided convex lens, and both the concave pit and the convex shape are conical.

12. The optical detection device according to any one of claims 1 to 11, characterized in that: The optical detection device further includes an image acquisition unit, which is used to receive an outgoing light beam reflected by the object to be tested and ultimately form an image of the object to be tested; the outgoing light beam enters the image acquisition unit after being transmitted by the bright field spectrometer.

13. The optical detection device according to claim 12, characterized in that: The bright field spectroscopic unit is a semi-transparent and semi-reflective mirror.

14. The optical detection device according to any one of claims 1 to 11, characterized in that: The optical detection device further comprises a laser and a laser beam splitter matched with the laser. The focusing laser emitted by the laser enters the objective lens after being reflected by the laser beam splitter.

15. The optical detection device according to any one of claims 1 to 11, characterized in that: The optical detection device further comprises an objective lens switching platform, on which a plurality of objective lenses are arranged. The objective lens switching platform can realize switching between different objective lenses, thereby realizing imaging of the sample at different magnifications.

Images