CN117969527A

CN117969527A - Optical detection device

Info

Publication number: CN117969527A
Application number: CN202410135202.0A
Authority: CN
Inventors: 李小虎; 朱婧; 熊星; 刘梦茹
Original assignee: Suzhou HYC Technology Co Ltd
Current assignee: Suzhou HYC Technology Co Ltd
Priority date: 2024-01-31
Filing date: 2024-01-31
Publication date: 2024-05-03

Abstract

The invention discloses an optical detection device, comprising: the system comprises an objective lens, a bright field illumination unit and a dark field illumination unit, wherein 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 light splitting unit and a bright field light source for providing bright field incident light beams, wherein the bright field incident light beams enter a bright field light channel after being reflected by the bright field light splitting unit; 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 light splitting unit; the prism module and the dark field light splitting unit are sequentially arranged along the transmission direction of the incident light beam of the dark field; the prism module is used for converting the incident light beam of the dark field into annular light spots, and the annular light spots enter the dark field light channel after being reflected by the dark field light splitting unit; the dark field light splitting unit comprises an annular spectroscope and a perforation arranged at the center of the annular spectroscope, and the perforation is positioned on the transmission path of the incident light beam of the bright field. The invention realizes the switching between bright field detection and dark field detection more conveniently, and improves the detection efficiency.

Description

Optical detection device

Technical Field

The invention relates to the field of microscopic detection, in particular to optical detection equipment.

Background

Defect detection generally refers to detection of defects on the surface of a sample, including, but not limited to, foreign contaminants, abnormal protrusions on the surface of the sample, scratches on the surface of the sample, grooves on the surface of the sample, deformation of specific pattern structures on the surface of the sample, and the like. Defect detection is in great demand in various industrial processes, such as the fields of integrated circuits, display panels, glass and metal products. Particularly, in integrated circuit production, wafer surface defect detection is one of the essential key process flows, and unqualified wafers with defects can be accurately detected, so that the yield of products can be greatly improved.

In order to more comprehensively detect the wafer, the existing optical detection equipment respectively detects the bright field environment and the dark field environment of the wafer. Detection optical dark field microscopy in dark field environment is the main method for detecting surface defects of a sample. The optical dark field microscopy is a detection means with simple structure, no label and high real-time property, and is characterized in that only scattered light of an object to be detected is collected for imaging, illumination light reflected or transmitted by the surface of a sample is not collected, and dark background and bright target signals form obvious contrast in a detection image.

When changing from the bright field environment to the dark field environment or from the dark field environment to the bright field environment in the wafer detection process, the wafer needs to be moved to different detection stations, so that the detection process is complex and the detection efficiency is low.

Disclosure of Invention

The invention aims to provide optical detection equipment, which solves the defects in the prior art, can ensure that all components of bright field imaging and all components of dark field imaging do not interfere with each other, and can realize independent imaging respectively; only the light source needs to be adjusted in the switching process between the bright field detection and the dark field detection, the corresponding light source can be controlled according to the needs, the switching between the bright field detection and the dark field detection is realized more conveniently, and the detection efficiency is improved.

The present invention provides an optical detection apparatus comprising:

an objective lens having a bright field light channel and a dark field light channel;

The bright field illumination unit comprises a bright field light splitting unit and a bright field light source for providing a bright field incident light beam for the object to be detected, wherein the bright field incident light beam enters the bright field light channel after being reflected by the bright field light splitting unit;

The dark field illumination unit comprises a dark field light source for emitting a dark field incident light beam to the object to be detected, a prism module and a dark field light splitting unit; the prism module and the dark field light splitting unit are sequentially arranged along the transmission direction of the incident light beam of the dark field; the prism module is used for converting a dark field incident light beam emitted by the dark field light source into an annular light spot, and the annular light spot enters the dark field light channel after being reflected by the dark field light splitting unit;

The dark field light splitting unit comprises an annular spectroscope and a perforation arranged at the center of the annular spectroscope, and the perforation is positioned on the transmission path of the incident light beam of the bright field.

Further, the prism module comprises a concave conical mirror and a convex conical mirror arranged at the center of the concave conical mirror, wherein the center of the convex conical mirror is opposite to the perforation position at the center of the annular reflector;

The dark field incident light beam is reflected by the convex conical mirror and then reaches the concave conical mirror, and the concave conical mirror reflects the dark field incident light beam to the annular spectroscope.

Further, the convex conical mirror can be adjusted in a moving mode along the axial direction of the concave conical mirror.

Further, the prism module and the dark field light source are positioned on two opposite sides of the annular reflector;

The annular reflector is provided with a dark field reflecting surface, the bright field light splitting unit is provided with a bright field reflecting surface, and the direction of the dark field reflecting surface is mutually perpendicular to the direction of the bright field reflecting surface.

Further, the prism module comprises a single-sided concave lens and a single-sided convex lens which are sequentially arranged along a dark field incident light beam transmission path, and the single-sided concave lens is concavely arranged in a direction deviating from the single-sided convex lens; the single-sided convex lens is arranged in a protruding way towards the direction of the single-sided concave lens;

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 spot to irradiate on the annular spectroscope.

Further, a dark field incident light beam irradiates the single-sided concave lens along an axial direction of the single-sided concave lens.

Further, the distance between the single-sided concave lens and the single-sided convex lens is adjustable.

Further, a focusing lens is arranged between the single-sided convex lens and the annular spectroscope.

Further, the prism module and the dark field light source are positioned on the same side of the annular reflector;

the annular reflector is provided with a dark field reflecting surface, the bright field light splitting unit is provided with 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.

Further, the optical detection device further comprises an image acquisition unit, wherein the image acquisition unit is used for receiving the emergent light beam reflected by the object to be detected and finally forming an image of the object to be detected; the emergent light beam enters the image acquisition unit after being transmitted by the bright field light splitting unit.

Compared with the prior art, the invention can generate annular light spots through the arrangement of the prism module, and the annular light spots are reflected into the dark field light channel of the objective lens after being reflected by the annular spectroscope so as to form dark field detection light irradiated on an object to be detected; because the center of the annular spectroscope is provided with the perforation which is positioned on the transmission path of the incident light beam of the bright field, the mutual interference between each part of the bright field imaging and each part of the dark field imaging is avoided, and the bright field imaging and the dark field imaging can realize independent imaging respectively; in the optical detection process, only the adjustment of the light source is needed in the switching process between the bright field detection and the dark field detection, the corresponding light source can be controlled according to the needs, the switching of the bright field detection and the dark field detection is realized more conveniently, and the detection efficiency is improved.

Drawings

FIG. 1 is a schematic diagram of an optical detection device according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of an optical detection device according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of an optical detection device according to a second embodiment of the present invention;

FIG. 4 is a schematic diagram of an optical detection device according to a second embodiment of the present invention;

Reference numerals illustrate: 1-objective lens, 11-bright field light channel, 12-dark field light channel, 2-bright field lighting unit, 21-bright field light splitting unit, 22-bright field light source, 3-dark field lighting unit, 31-dark field light source, 32-prism module, 321-concave conical lens, 322-convex conical lens, 323-single-sided concave lens, 324-single-sided convex lens, 325-collecting lens, 33-dark field light splitting unit, 331-annular spectroscope, 332-perforation, 4-image acquisition unit, 5-objective lens switching platform, 6-laser and 7-laser beam splitter.

Detailed Description

The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.

Embodiments of the invention: as shown in fig. 1 to 4, an optical detection apparatus is disclosed, comprising: an objective lens 1, a bright field illumination unit 2 and a dark field illumination unit 3;

The objective lens 1 is used for focusing an object to be measured so as to observe the object to be measured from an eyepiece or an image acquisition unit, the object to be measured can be a wafer, for example, it can be understood that, for conveniently realizing the placement of the object to be measured, the optical detection device further has an objective table, the objective table is used for positioning and supporting the object to be measured, and the objective lens 1 is located above the objective table. Under the cooperation of the bright field illumination unit 2, the objective lens 1 can enable the object to be detected to carry out bright field imaging, and under the cooperation of the dark field illumination unit 3, the objective lens 1 can enable the object to be detected to carry out dark field imaging.

The bright field illumination unit 2 emits a bright field incident beam to the object to be measured through the objective lens 1, and the dark field illumination unit 3 emits a dark field incident beam to the object to be measured through the objective lens 1. In order to enable the bright-field incident light beam and the dark-field incident light beam to pass through the objective lens 1, the objective lens 1 of the present embodiment has a bright-field light channel 11 and a dark-field light channel 12; the bright field incident beam irradiates the object to be measured through the bright field light channel 11, and the dark field incident beam irradiates the object to be measured through the dark field light channel 12.

Compared with the mode that the oblique dark field light source is adopted most originally and does not penetrate through the objective lens to directly irradiate on the object to be detected, the objective lens 1 of the embodiment can penetrate through the bright field illumination and the dark field illumination at the same time, and can save more space structurally and avoid occupation of lateral space of the microscopic detection device. It should be noted that, the internal structure of the objective lens 1 is designed in the prior art, and the structure of the objective lens 1 is not improved in the present application.

The bright field illumination unit 2 comprises a bright field light splitting unit 21 and a bright field light source 22 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 11 after being reflected by the bright field light splitting unit 21; the bright field incident beam irradiates the object to be measured after passing through the bright field light channel 11. The bright field incident beam is emitted from the bright field light channel 11 and then irradiates on the object to be measured on the object stage along the direction almost perpendicular to the plane of the object stage.

The dark field illumination unit 3 includes a dark field light source 31 that emits a dark field incident light beam to the object to be measured, a prism module 32, and a dark field spectroscopic unit 33; the prism module 32 and the dark field beam splitting unit 33 are sequentially arranged along the transmission direction of the dark field incident beam; the prism module 32 is configured to convert a dark field incident beam emitted from the dark field light source 31 into an annular light spot, and the annular light spot is reflected by the dark field light splitting unit 33 and enters the dark field light channel 12; the annular light spot irradiates the object to be measured in an oblique direction after passing through the dark field light channel 12. The dark field incident beam is emitted from the dark field optical channel 12 and irradiates towards the object to be measured relatively along the direction of intersecting the plane of the object stage by an angle smaller than 90 degrees.

Because the light entering the dark field light channel 12 is an annular light spot, for better adaptation of the annular light spot, the dark field light channel 12 is also integrally annular, the objective lens 1 is generally cylindrical, the bright field light channel 11 extends along the central axis direction of the objective lens 1, the dark field light channel 12 is integrally annular and diffracts outside the bright field light channel 11, and the annular ring formed by the dark field light channel 12 and the bright field light channel 11 are coaxially arranged.

The bright field incident light beam irradiates on the object to be detected after passing through the bright field light channel 11 of the objective lens 1, and the bright field reflected light beam formed after the object to be detected is reflected back along the bright field light channel 11 and finally imaged at the eyepiece position or enters the image acquisition unit to be captured by the image acquisition unit.

The dark field incident beam irradiates on the object to be measured after passing through the dark field optical channel 12 and generates reflection and diffuse reflection, wherein the dark field reflected beam is emitted outwards from the objective lens 1, part of the diffuse reflected beam enters the bright field optical channel 11 and finally is imaged at the eyepiece position or enters the image acquisition unit to be captured by the image acquisition unit.

The dark field spectroscopic unit 33 includes an annular beam splitter 331 and a through hole 332 disposed at a center position of the annular beam splitter 331, the through hole 332 being located on a transmission path of the incident light beam of the bright field.

In the prior art, the center position of a part of light sources is generally shielded by a shielding sheet in the dark field imaging process, so that a point light source emitted by a lighting unit is diffracted into an annular light spot, and the intensity of the lighting unit is generally required to be improved when the detection effect of the annular light spot is improved in order to improve the detection effect of the annular light spot, and the whole switching process is not only required to be adjusted for equipment, but also required to be adjusted for illumination intensity, so that the switching efficiency is low.

In this embodiment, an annular light spot can be generated by the arrangement of the prism module 32, and the annular beam splitter 331 can reflect the annular light spot generated by the prism module 32, and the annular light spot is reflected into the dark field light channel 12 of the objective lens 1 after reflection to form dark field detection light irradiated on the object to be detected.

Because the perforation 332 is arranged at the center of the annular spectroscope 331 and is positioned on the transmission path of the incident light beam of the bright field, mutual interference between each part of bright field imaging and each part of dark field imaging is avoided, and the bright field imaging and the dark field imaging can be respectively and independently imaged.

In a specific embodiment, the bright field light source 22 and the dark field light source 31 may be two independent light sources, which are independently controlled. When bright field detection is performed, the bright field light source 22 is turned on and the dark field light source 31 is turned off, and when dark field detection is performed, the dark field light source 31 is turned on and the bright field light source 22 is turned on.

In another embodiment, the bright field light source 22 and the dark field light source 31 may be from the same light source, specifically, a light source controller may be disposed on a transmission path of the light source, and during bright field detection, a light beam emitted from the light source is guided onto a bright field detection path by the light source controller to form a bright field incident light beam, and during dark field detection, a light beam emitted from the light source is guided onto a dark field detection path by the light source controller to form a dark field incident light beam. It should be noted that the specific structure of the light source controller is not further limited herein, and the main purpose thereof is to change the light source to transmit on different paths.

Of course, the light source can also provide illumination for both bright field detection and dark field detection, and the effect of simultaneous imaging of the bright field and the dark field can be achieved by adjusting the occupation ratio of the illumination on the bright field detection route and the dark field detection route, so that the visual effect of the bright field imaging and the dark field imaging stack is obtained.

How to form annular light spots in the dark field imaging process is important, the central position of a point light source is generally shielded in the prior art, so that the point light source diffracts to form the annular light spots, and the result is low light source utilization efficiency. In this embodiment, the prism module 32 is arranged to generate the annular light spot on the premise of reducing the light source loss as little as possible, so as to further improve the effect of dark field imaging.

The prism module 32 includes at least two modes:

for the first prism module, as shown in fig. 1-2, the prism module 32 includes a concave cone 321 and a convex cone 322 disposed at the center of the concave cone 321, where the center of the convex cone 322 is opposite to the center of the through hole 332 of the annular reflector 331;

the dark field incident beam is reflected by the convex cone mirror 322 and then reaches the concave cone mirror 321, and the concave cone mirror 321 reflects the dark field incident beam to the annular beam splitter 331.

The dark field incident 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, the concave conical mirror 321 is opposite to the convex conical mirror 322, and the concave setting direction of the concave conical mirror 321 is opposite to the protruding direction of the convex conical mirror 322, so that the reflected beam is transmitted along the protruding direction of the convex conical mirror 322.

In this embodiment, the convex cone mirror 322 is conical in shape, and has an axial direction, and the light beam emitted from the dark field light source 31 is incident from the axial direction of the convex cone mirror 322.

In this embodiment, the prism module 32 and the dark field light source 31 are located at two opposite sides of the annular reflective mirror 331;

the annular mirror 331 has a dark field reflection surface, the bright field light splitting unit 21 has a bright field reflection surface, and the direction of the dark field reflection surface is perpendicular to the direction of the bright field reflection surface.

The included angle between the plane of the bright field reflecting surface and the horizontal plane is equal to the included angle between the plane of the dark field reflecting surface and the horizontal plane; the extending direction of the normal line direction of the bright field reflecting surface is mutually perpendicular to the extending direction of the normal line of the plane where the dark field reflecting surface is positioned.

The plane of the bright field reflecting surface is obliquely arranged at 45 degrees relative to the whole horizontal plane, and the plane of the dark field reflecting surface is obliquely arranged at 45 degrees relative to the whole horizontal plane.

Further, the convex conical mirror 322 can be movably adjusted along the axial direction of the concave conical mirror 321. The convex cone mirror 322 is close to or far from the annular beam splitter 331 along the axial direction of the concave cone mirror 321. When the convex cone mirror 322 approaches toward the annular beam splitter 331, a part of the convex cone mirror 322 leaves the corresponding concave cone mirror 321, so that only a part of the concave cone mirror 321 receives the reflection of the convex cone mirror 322, and the size of the formed annular light spot is narrowed.

When the convex cone mirror 322 is far away from the annular beam splitter 331, the convex cone mirror 322 corresponds to the concave cone mirror 321 completely, and the size of the formed annular light spot is relatively larger. From the above, the adjustment of the size and width of the formed annular light spot can be realized by controlling the movement of the convex conical mirror 322 in the axial direction of the concave conical mirror 321, so that different requirements can be met, and the adaptability is improved.

For the second prism module, as shown in fig. 3 to 4, the prism module 32 includes a single-sided concave lens 323 and a single-sided convex lens 324 sequentially disposed along a dark field incident beam transmission path, where the single-sided concave lens 323 is concavely disposed in a direction away from the single-sided convex lens 324; the single-sided convex lens 324 protrudes towards the direction where the single-sided concave lens 323 is located;

The dark field incident beam is refracted by the single-sided concave lens 323 and the single-sided convex lens 324 in sequence to form an annular light spot, and the annular light spot irradiates the annular spectroscope 331.

The annular light spots are formed by refraction on two sides of the single-sided concave lens 323 and the single-sided convex lens 324, and are reflected by the annular spectroscope 331 and then irradiate on an object to be measured.

In this embodiment, the concave pit formed in the middle of the single-sided concave lens 323 is tapered, and may be conical. The overall shape of the protrusion formed by the outward protrusion of the single-sided convex lens 324 is tapered, and in particular, the protrusion formed by the outward protrusion of the single-sided convex lens 324 is tapered.

The concave pit formed by the concave arrangement of the single-sided concave lens 323 in the present embodiment is adapted to the convex shape formed by the single-sided convex lens 324.

In order to form a ring-shaped light spot, a dark field incident light beam emitted from the dark field light source 31 irradiates the single-sided concave lens 323 along the axial direction of the single-sided concave lens 323. The dark field incident beam is incident from the side of the single-sided concave lens 323, which is away from the single-sided convex lens 324, is refracted by the single-sided concave lens 324, enters the single-sided convex lens 324, and is refracted by the single-sided convex lens 324 to form an annular light spot.

The space between the single-sided concave lens 323 and the single-sided convex lens 324 is adjustable. The width of the annular light spot can be adjusted by adjusting the distance between the single-sided concave lens 323 and the single-sided convex lens 324, so that different detection requirements are met, and the adaptability is improved.

Further, the prism module 32 further includes a focusing lens 325, and the focusing lens 325 is disposed between the single-sided convex lens 324 and the annular beam splitter 331. The focusing lens 325 is a lens with two protruding sides, and after further refraction of the focusing lens 325, a more regular annular light spot can be formed, so that the energy of the light source is better concentrated, and the loss of the light source is reduced.

The prism module 32 and the dark field light source 31 are positioned on the same side of the annular reflector 331; the annular mirror 331 has a dark field reflection surface, and the bright field light splitting unit 21 has a bright field reflection surface, and the direction of the dark field reflection surface is the same as the direction of the bright field reflection surface.

The included angle between the plane of the bright field reflecting surface and the horizontal plane is equal to the included angle between the plane of the dark field reflecting surface and the horizontal plane; the plane of the bright field reflecting surface is obliquely arranged at 45 degrees relative to the whole horizontal plane, and the plane of the dark field reflecting surface is obliquely arranged at 45 degrees relative to the whole horizontal plane. The extending direction of the normal line direction of the bright field reflecting surface is parallel to the extending direction of the normal line of the plane where the dark field reflecting surface is located.

The arrangement of the bright field reflecting surface and the dark field reflecting surface enables outgoing light beams of the lighting unit to enter the reflecting surface along the transverse direction, and reflected light beams entering the objective lens along the vertical direction can be formed after being reflected by the reflecting surface, so that the lighting unit is more conveniently arranged.

Of course, in other embodiments, the included angle between the plane of the bright field reflective surface and the horizontal plane may be unequal to the included angle between the plane of the dark field reflective surface and the horizontal plane. The included angle between the plane of the bright field reflecting surface and the horizontal plane can be adjusted according to the requirement, and is not limited to 45 degrees. When the angle between the plane of the bright field reflecting surface and the horizontal plane is adjusted, the angle of the incident beam irradiated on the bright field reflecting surface needs to be correspondingly adjusted, so that the incident beam can form the beam irradiated towards the objective lens 1 after being reflected by the bright field reflecting surface.

Correspondingly, the included angle between the plane where the dark field reflecting surface is located and the horizontal plane can be set according to the requirement, and in order to realize that the light beam reflected by the dark field reflecting surface enters the objective lens 1 along the vertical direction during adjustment, the angle of the light beam emitted from the dark field lighting unit to the dark field reflecting surface needs to be adjusted correspondingly.

It can be understood that the optical detection device further includes an image acquisition unit 4, where the image acquisition unit 4 is configured to receive the outgoing light beam reflected by the object to be detected and finally form an image of the object to be detected; the outgoing light beam enters the image acquisition unit 4 after being transmitted by the bright field light splitting unit 21; the image capturing unit 4 is a camera in this embodiment.

Since the image capturing unit 4 is located at a side of the bright field beam splitting unit 21 away from the objective lens 1, and the reflected light beam reflected by the object to be detected needs to enter the image capturing unit 4 for imaging after passing through the objective lens 1, the reflected light beam needs to permeate the bright field beam splitting unit 21, and meanwhile the bright field beam splitting unit 21 also plays a role of reflecting the incident light beam of the bright field to the objective lens 1, in this embodiment, the bright field beam splitting unit 21 is a half-transparent half-mirror, and has a reflecting surface capable of reflecting the incident light beam to the objective lens 1, and meanwhile, the reflected light beam can be permeated so as to transmit the reflected light beam to the image capturing unit 4.

It should be noted that two image capturing units 4 may be provided, where the two image capturing units 4 are respectively used to capture a bright field detection image and a dark field detection image, and the two image capturing units 4 may work in turn, or the image capturing unit 4 may be linked with the light source controller, where when the light source emits a bright field incident beam, the image capturing unit 4 that captures a bright field image works, and when the light source emits a dark field incident beam, the image capturing unit 4 that captures a dark field image works.

As shown in fig. 1 and 3, in order to enable the optical detection device to be used at different objective lens multiples, the optical detection device further has an objective lens switching platform 5, and a plurality of objective lenses 1 are arranged on the objective lens switching platform 5, so that the objective lens switching platform can enable the switching of different objective lenses, and therefore imaging of a sample at different multiplying powers is achieved.

Further, in order to realize automatic focusing, the optical detection device further comprises a laser 6 and a laser beam splitting component 7 matched with the laser 6, and focusing laser emitted by the laser 6 enters the objective lens 1 after being reflected by the laser beam splitting component.

While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. An optical inspection apparatus, comprising:

2. The optical detection apparatus according to claim 1, wherein: the prism module comprises a concave conical lens and a convex conical lens arranged at the center of the concave conical lens, and the center of the convex conical lens is opposite to the perforation position at the center of the annular reflector;

3. The optical detection apparatus according to claim 2, wherein: the convex conical mirror can be moved and adjusted along the axial direction of the concave conical mirror.

4. The optical detection apparatus according to claim 2, wherein: the prism module and the dark field light source are positioned on two opposite sides of the annular reflector;

5. The optical detection apparatus according to claim 1, wherein: the prism module comprises a single-sided concave lens and a single-sided convex lens which are sequentially arranged along a dark field incident light beam transmission path, and the single-sided concave lens is concavely arranged in a direction deviating from the single-sided convex lens; the single-sided convex lens is arranged in a protruding way towards the direction of the single-sided concave lens;

6. The optical detection apparatus according to claim 5, wherein: the dark field incident light beam irradiates the single-sided concave lens along the axial direction of the single-sided concave lens.

7. The optical detection apparatus according to claim 6, wherein: the space between the single-sided concave lens and the single-sided convex lens is adjustable.

8. The optical detection apparatus according to claim 5, wherein: and a focusing lens is arranged between the single-sided convex lens and the annular spectroscope.

9. The optical detection apparatus according to claim 5, wherein: the prism module and the dark field light source are positioned on the same side of the annular reflector;

10. The optical detection apparatus according to any one of claims 1 to 7, further comprising an image acquisition unit for receiving the outgoing light beam reflected by the object to be detected and finally forming an image of the object to be detected; the emergent light beam enters the image acquisition unit after being transmitted by the bright field light splitting unit.