A dark-field ring illumination device and optical detection system

Abstract

This invention provides a dark-field ring illumination device and an optical inspection system, relating to the field of optical technology. The dark-field ring illumination device provides a light source that outputs an illumination beam, which is split into a first beam and a second beam by a prism beam splitting unit. An optical path transmission unit includes a first reflector and a second reflector. The first reflector reflects the first beam to an optical path refraction unit, and the second reflector reflects the second beam to the same unit. The optical path refraction unit changes the transmission direction of the first and second beams, transmitting them to a ring illumination shaping unit. The ring illumination shaping unit modulates the first and second beams into an arc shape and splices them into a ring-shaped illumination field of view for the object under test. This dark-field ring illumination device improves beam transmission efficiency and ensures omnidirectional defect detection capability.

Description

Technical Field

[0001] This invention relates to the field of optical inspection technology, and in particular to a dark-field ring illumination device and an optical inspection system. Background Technology

[0002] Optical inspection methods hold a dominant position in the field of semiconductor inspection. Among them, the scheme in which the imaging system receives the transmitted or reflected light from the target is called the bright-field scheme, and the scheme in which the imaging system receives the scattered light from the target is called the dark-field scheme. Because the scattered light signal in the dark-field scheme is much smaller than the reflected light signal in the bright-field scheme, it places higher demands on the illumination intensity of the light source and the energy transfer efficiency of the system.

[0003] In dark field lighting solutions, single-phase light sources become ineffective at specific angles; therefore, ring light sources are generally used in current dark field solutions. Existing technologies require the use of optical fibers to convert ordinary light sources into ring light sources, which significantly attenuates the light intensity, sometimes by more than 50%. This significant attenuation can lead to insufficient lighting and energy waste. Summary of the Invention

[0004] This invention provides a dark-field ring illumination device and an optical inspection system, which improves beam transmission efficiency and ensures omnidirectional defect detection capability.

[0005] On one hand, embodiments of the present invention provide a dark field ring illumination device, including a light source, a prism beam splitting unit, an optical path transmission unit, an optical path reversal unit, and a ring illumination shaping unit;

[0006] The light source is used to output an illumination beam, which is then split into a first beam and a second beam by a prism beam splitting unit.

[0007] The optical path transmission unit includes a first reflector and a second reflector. The first reflector is used to reflect a first light beam to the optical path deflection unit, and the second reflector is used to reflect a second light beam to the optical path deflection unit.

[0008] The optical path deflection unit is used to change the transmission direction of the first beam and the second beam, and transmit the first beam and the second beam to the ring illumination shaping unit.

[0009] The ring illumination shaping unit is used to modulate the first beam and the second beam into an arc shape and splice them into a ring illumination field of view to the object being measured.

[0010] Optionally, the optical path transmission unit includes a convex reflector, and the ring illumination shaping unit includes a conical lens;

[0011] The first and second beams are diverged and reflected by the convex mirror to the conical lens, which modulates the received beams into a ring-shaped illumination field of view.

[0012] Optionally, the convex reflector includes a first convex reflector and a second convex reflector, wherein the first convex reflector reflects a first light beam and the second convex reflector reflects a second light beam; or the convex reflector includes a hollow convex reflector, wherein both the first light beam and the second light beam are reflected by the hollow convex reflector.

[0013] Optionally, the optical path transmission unit includes a concave reflector, and the ring illumination shaping unit includes a spherical reflector group;

[0014] The first and second beams converge and reflect through a concave mirror to a spherical mirror assembly, which modulates the received beams into a ring-shaped illumination field of view.

[0015] Optionally, the concave reflector includes a first concave reflector and a second concave reflector, wherein the first concave reflector reflects a first beam and the second concave reflector reflects a second beam; or the concave reflector includes a hollow concave reflector, wherein both the first beam and the second beam are reflected by the hollow concave reflector.

[0016] The spherical mirror assembly includes a central convex spherical mirror and a first concave spherical mirror and a second concave spherical mirror located on either side of the central convex spherical mirror. The light reflected by the concave mirrors converges to the central convex spherical mirror, and the light reflected by the central convex spherical mirror forms a ring-shaped illumination field after being reflected by the first or second concave spherical mirror.

[0017] Optionally, the number of light sources, prism beam splitting units, and optical path transmission units is at least two, and the ring illumination shaping unit modulates the output beams of at least two light sources into an arc shape and splices them into a ring illumination field of view to the object under test.

[0018] Optionally, the dark field ring illumination device also includes a collimation and homogenization unit, which is located between the light source and the prism beam splitting unit. The illumination beam output by the light source is collimated by the collimation and homogenization unit and then incident on the prism beam splitting unit.

[0019] Optionally, the dark field ring illumination device also includes an imaging optical path unit and a camera. The light from the object being measured or scattered light is incident on the imaging optical path unit and converges to the imaging surface of the camera after passing through the imaging optical path unit.

[0020] Optionally, the outer diameter of the imaging optical path unit is smaller than the minimum inner diameter of the optical path deflection unit and the ring illumination shaping unit, and the imaging optical path unit is surrounded by the optical path deflection unit and the ring illumination shaping unit.

[0021] On the other hand, embodiments of the present invention also provide an optical detection system, including a dark field ring illumination device provided in any embodiment of the present invention.

[0022] The dark-field ring illumination device provided in this embodiment of the invention uses a prism beam splitting unit to split the illumination beam, avoiding the use of optical fibers, thereby avoiding energy loss when the beam is coupled into and out of the optical fibers, reducing losses during beam transmission, and improving beam transmission efficiency; the beam after splitting is modulated into a ring beam by an optical path turning unit and a ring illumination shaping unit, forming a dark-field ring illumination on the detection surface of the object under test, so that the detection surface is illuminated by beams from all directions, ensuring omnidirectional defect detection capability.

[0023] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily apparent from the following description. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in this embodiment, the accompanying drawings used in the description of the embodiment will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this embodiment. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a dark field ring lighting device provided in an embodiment of the present invention;

[0026] Figure 2 This is a beam splitting path diagram of the prism beam splitting unit provided in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of another dark-field ring lighting device provided in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the structure of another dark field ring lighting device provided in an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the structure of another dark field ring lighting device provided in an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the structure of another dark field ring lighting device provided in an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the structure of another dark field ring lighting device provided in an embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram of the structure of another dark field ring lighting device provided in an embodiment of the present invention;

[0033] Figure 9This is a three-dimensional structural schematic diagram of a dark field ring lighting device provided in an embodiment of the present invention;

[0034] Figure 10 This is a top view schematic diagram of the imaging optical path unit, optical path reversal unit, and ring illumination shaping unit provided in the embodiments of the present invention;

[0035] Figure 11 This is a partial optical path diagram of a dark field ring lighting device provided in an embodiment of the present invention. Detailed Implementation

[0036] To enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments, and not all of the embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0037] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0038] Figure 1 This is a schematic diagram of a dark-field ring lighting device provided in an embodiment of the present invention, for reference. Figure 1 This invention provides a dark-field ring illumination device, including a light source 1, a prism beam splitting unit 2, an optical path transmission unit 3, an optical path reversal unit 5, and a ring illumination shaping unit 6. The light source 1 outputs an illumination beam, which is split into a first beam and a second beam by the prism beam splitting unit 2. The optical path transmission unit 3 includes a first reflector 31 and a second reflector 32. The first reflector 31 reflects the first beam to the optical path reversal unit 5, and the second reflector 32 reflects the second beam to the optical path reversal unit 5. The optical path reversal unit 5 changes the transmission direction of the first beam and the second beam, transmitting them to the ring illumination shaping unit 6. The ring illumination shaping unit 6 modulates the first beam and the second beam into an arc shape and splices them into a ring illumination field of view for the object under test 7.

[0039] refer to Figure 1 The illumination beam emitted from the light source 1 can be parallel light, and the illumination beam is incident on the prism beam splitting unit 2. Figure 2 This is a beam splitting path diagram of the prism beam splitting unit provided in an embodiment of the present invention, for reference. Figure 2 The prism beam splitting unit 2 includes a first incident surface 21, a second incident surface 22, and an exit surface 23. The first illumination beam S1, entering the prism beam splitting unit 2 from the first incident surface 21, undergoes refraction upon passing through the first incident surface 21, changing its propagation direction. It then undergoes further refraction upon exiting from the exit surface 23. Similarly, the second illumination beam S2, entering the prism beam splitting unit 2 from the second incident surface 22, also changes its propagation direction twice upon passing through the second incident surface 22 and the exit surface 23. Because the angles of the first incident surface 21 and the second incident surface 22 are different, the final exit angles of the first illumination beam S1 and the second illumination beam S2 are also different, thus splitting the illumination beam into a first beam and a second beam. (Reference) Figure 1 The first beam is reflected by the first reflector 31 to the optical path reversal unit 5, and the second beam is reflected by the second reflector 32 to the optical path reversal unit 5. Then, the first beam and the second beam are incident on the ring illumination shaping unit 6 after passing through the optical path reversal unit 5. The first beam and the second beam are respectively modulated into arc-shaped beams by the ring illumination shaping unit 6 and spliced ​​together to form a ring beam. Figure 3 This is a schematic diagram of another dark-field ring lighting device provided in an embodiment of the present invention, for reference. Figure 3 The illumination beam emitted by light source 1 is split into a first beam and a second beam by prism beam splitting unit 2. The first beam and the second beam pass through the optical path transmission unit ( Figure 3 Not shown in the diagram), optical path turning unit ( Figure 3 (not shown in the image) and ring lighting shaping unit ( Figure 3 (Not shown in the image) After modulation, the images are spliced ​​together to form a ring-shaped illumination field of view.

[0040] The dark-field ring illumination device provided in this embodiment of the invention uses a prism beam splitting unit to split the illumination beam, avoiding the use of optical fibers, thereby avoiding energy loss when the beam is coupled into and out of the optical fibers, reducing losses during beam transmission, and improving beam transmission efficiency; the beam after splitting is modulated into a ring beam by an optical path turning unit and a ring illumination shaping unit, forming a dark-field ring illumination on the detection surface of the object under test, so that the detection surface is illuminated by beams from all directions, ensuring omnidirectional defect detection capability.

[0041] Figure 4 This is a schematic diagram of another dark-field ring lighting device provided in an embodiment of the present invention, for reference. Figure 4Optionally, the optical path transmission unit 5 includes a convex reflector 51, and the ring illumination shaping unit 6 includes a conical lens 61; the first beam and the second beam are diverged and reflected by the convex reflector 51 to the conical lens 61, and the conical lens 61 modulates the received beam into a ring illumination field of view.

[0042] refer to Figure 4 The first beam is reflected by the first plane mirror 31 to the convex mirror 5, and the second beam is reflected by the first plane mirror 32 to the convex mirror 51. After being reflected by the convex mirror 51, the first and second beams are modulated by the conical lens 61 into a first arc-shaped beam and a second arc-shaped beam, respectively. The first and second arc-shaped beams combine to form a ring beam. Optionally, the convex mirror 51 includes a first convex mirror and a second convex mirror, with the first convex mirror reflecting the first beam and the second convex mirror reflecting the second beam; or the convex mirror includes a hollow convex mirror, with both the first and second beams reflected by the hollow convex mirror. The specific implementation can be designed according to the actual situation.

[0043] Figure 5 This is a schematic diagram of another dark-field ring lighting device provided in an embodiment of the present invention, for reference. Figure 5 Optionally, the optical path transmission unit 5 includes a concave reflector 52, and the ring illumination shaping unit 6 includes a spherical reflector group; the first beam and the second beam are converged and reflected by the concave reflector 52 to the spherical reflector group, and the spherical reflector group modulates the received beam into a ring illumination field of view.

[0044] refer to Figure 5 The first beam is reflected by the first plane mirror 31 to the concave mirror 52, and the second beam is reflected by the first plane mirror 32 to the concave mirror 52. The concave mirror 52 converges and reflects the first and second beams to the spherical mirror group. The spherical mirror group modulates the first and second beams into a third and a fourth arc-shaped beam, respectively. The third and fourth arc-shaped beams combine to form a ring beam.

[0045] Optionally, the concave reflector 52 includes a first concave reflector and a second concave reflector, the first concave reflector reflecting a first beam and the second concave reflector reflecting a second beam; or the concave reflector includes a hollow concave reflector, the first beam and the second beam are both reflected by the hollow concave reflector; the spherical reflector group includes a central convex spherical reflector 11 and a first concave spherical reflector 12 and a second concave spherical reflector 13 located on both sides of the central convex spherical reflector, the light reflected by the concave reflector 52 (which can be two concave reflectors or a hollow concave reflector) converges to the central convex spherical reflector 11, and the reflected light from the central convex spherical reflector 11 forms an annular illumination field after being reflected by the first concave spherical reflector 12 or the second concave spherical reflector 13.

[0046] refer to Figure 5 The first and second beams are converged and reflected by the concave mirror 52 to the convex spherical mirror 11. The convex spherical mirror 11 reflects the incident beam onto the first concave spherical mirror 12 or the second concave spherical mirror 13. Then, the first concave spherical mirror 12 and the second concave spherical mirror 13 reflect the beams incident on themselves onto the object under test 7. The reflected light output by the first concave spherical mirror 12 and the reflected light output by the second concave spherical mirror 13 are combined to form a ring-shaped illumination field of view.

[0047] Optionally, the number of light sources, prism beam splitting units, and optical path transmission units is at least two, and the ring illumination shaping unit modulates the output beams of at least two light sources into an arc shape and splices them into a ring illumination field of view to the object under test.

[0048] Figure 6 This is a schematic diagram of another dark-field ring lighting device provided in an embodiment of the present invention, for reference. Figure 6 The light source 1 includes a first light source 101 and a second light source 102. The prism beam splitting unit 2 includes a first prism beam splitting unit 201 and a second prism beam splitting unit 202. The illumination beam emitted by the first light source 101 is split into a first beam and a second beam by the first prism beam splitting unit 201. The first beam is reflected by the first reflector 31 to the ring illumination shaping unit. Figure 6 (Not shown), the second beam is reflected by the second reflector 32 to the ring illumination shaping unit; the illumination beam emitted by the second light source 102 is split into a third beam and a fourth beam by the second prism beam splitting unit 202, the third beam is reflected by the third reflector 33 to the ring illumination shaping unit, and the fourth beam is reflected by the fourth reflector 34 to the ring illumination shaping unit. After being modulated by the ring illumination shaping unit, the first beam, the second beam, the third beam and the fourth beam all become arc beams and can be spliced ​​into a ring illumination field of view.

[0049] Figure 7 This is a schematic diagram of another dark-field ring lighting device provided in an embodiment of the present invention, for reference. Figure 7 Optionally, the dark field ring illumination device also includes a collimation and homogenization unit 16, which is located between the light source 1 and the prism beam splitting unit 2. The illumination beam output by the light source 1 is collimated by the collimation and homogenization unit 16 and then incident on the prism beam splitting unit 2.

[0050] In this embodiment, the light beam emitted by the light source 1 may not be a parallel beam. After passing through the collimation and homogenization unit 16, the illumination beam output by the light source 1 becomes a parallel beam. The transmission direction of the parallel beam in the dark field ring illumination device is more controllable and will not diverge during transmission.

[0051] Optionally, the dark field ring illumination device also includes an imaging optical path unit 17 and a camera 18. The light scattered by the object under test 7 is incident on the imaging optical path unit 17 and converges to the imaging surface of the camera 18 after passing through the imaging optical path unit 17.

[0052] The structure of the imaging optical path unit 17 can be designed according to actual conditions, such as including a fixed-focus or zoom lens. This embodiment of the invention does not limit the structure of the imaging optical path unit 17.

[0053] Figure 8 This is a schematic diagram of another dark-field ring lighting device provided in an embodiment of the present invention, for reference. Figure 8 The illumination beam emitted by the light source 1 is split into a first beam and a second beam by the prism beam splitting unit 2. The first beam is reflected by the first reflector 31 to the optical path reversal unit 5, and the second beam is reflected by the second reflector 32 to the optical path reversal unit 5. Then, the first beam and the second beam are incident on the ring illumination shaping unit 6 after passing through the optical path reversal unit 5. The first beam and the second beam are respectively modulated into arc-shaped beams by the ring illumination shaping unit 6 and spliced ​​to form a ring illumination field of view. The ring illumination field of view illuminates the object under test 7. The light scattered by the object under test 7 is incident on the imaging optical path unit 17. The imaging optical path unit 17 is set above the object under test 7 and on the same side as the ring illumination shaping unit 6. Thus, the imaging optical path unit 17 can receive the light scattered by the object under test 7 and then converge the received light scattered by the object under test 7 onto the imaging surface of the camera 18, thereby imaging the defects on the surface of the object under test 7. Figure 9 This is a three-dimensional structural schematic diagram of a dark field ring lighting device provided in an embodiment of the present invention, for reference. Figure 9 The optical path reversing unit 5 and the ring illumination shaping unit 6 have hollow parts. The imaging optical path unit 17 can be disposed in the hollow parts of the optical path reversing unit 5 and the ring illumination shaping unit 6 to receive the light scattered by the object under test 7.

[0054] Optionally, the outer diameter of the imaging optical path unit 17 is smaller than the minimum inner diameter of the optical path deflection unit 5 and the annular illumination shaping unit 6.

[0055] Figure 10 This is a top view schematic diagram of the imaging optical path unit, optical path deflection unit, and ring illumination shaping unit provided in the embodiments of the present invention, combined with... Figure 9 and Figure 10As shown, if the diameter of the imaging optical path unit 17 is larger than the minimum diameter of the optical path deflection unit 5 and the ring illumination shaping unit 6, the imaging optical path unit 17 will block part of the ring illumination light formed by the optical path deflection unit 5 and the ring illumination shaping unit 6, thus preventing it from illuminating the object under test 7. Therefore, the diameter of the imaging optical path unit 17 must be smaller than the minimum diameter of the optical path deflection unit 5 and the ring illumination shaping unit 6, so that the ring illumination light formed by the optical path deflection unit 5 and the ring illumination shaping unit 6 can illuminate the object under test 7. (Reference) Figure 2 Assuming the illumination beam is parallel, and prism beam splitter unit 2 is a triangular prism with refractive index n and apex angle θ, and the illumination beam is incident on prism beam splitter unit 2, then:

[0056]

[0057] sinθ1 = n·sinθ2;

[0058] θ3 = θ1 - θ2;

[0059] n·sinθ3=sinθ4.

[0060] Therefore, we can conclude that:

[0061]

[0062] Figure 11 This is a partial optical path schematic diagram of a dark-field ring lighting device provided in an embodiment of the present invention, for reference. Figure 11 Assume the illumination beam size of the incident prism beam splitter 2 is 2D1×2D1, and the light spot is symmetrical along the Y-axis and Z-axis. The thickness of the prism beam splitter 2 is h. The projection length of the distance from the prism beam splitter 2 to the center position of the light spot of the first reflector 31 and the second reflector 32 on the X-axis is D2. The projection length of the center position of the light spot of the first reflector 31 and the second reflector 32 to the central optical axis of the imaging optical path unit 17 on the X-axis is D3. After the first reflector 31 and the second reflector 32 are projected onto the XOY plane, the angle between their reflecting surfaces and the X-axis direction is θ5. At this time, the light beam emitted from the first reflecting mirror 31 and the second reflecting mirror 32 illuminates the light path deflection unit 5 (not shown in the figure), and the projection 19 of the light spot on the XOY plane is an annular shape. The inner and outer radii of the projection 19 correspond to the positions of the light spot on the prism beam splitting unit 2 at the highest or lowest point of the Z-axis. Here, it is assumed that the width of the annular projection 19 is r1, that is, the difference between the inner and outer diameters of the projection 19 is r1. Then, when the radius D of the imaging light path unit 17 satisfies:

[0063]

[0064] The radius of the imaging optical path unit 17 is smaller than the minimum radius of the illumination field of view.

[0065] Based on the same inventive concept, embodiments of the present invention also provide an optical detection system, including a dark field ring illumination device according to any embodiment of the present invention.

[0066] Since the optical detection system provided in this embodiment includes any of the dark field ring illumination devices provided in the above embodiments, and has the same or corresponding technical effects as the dark field ring illumination devices, it will not be described in detail here.

[0067] The specific embodiments described above do not constitute a limitation on the scope of this protection. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of this protection.

Claims

1. A ring-shaped lighting device for dark fields, characterized in that, It includes a light source, a prism beam splitting unit, a light path transmission unit, a light path folding unit, and a ring illumination shaping unit; The light source is used to output an illumination beam, which is split into a first beam and a second beam by the prism beam splitting unit. The optical path transmission unit includes a first reflector and a second reflector. The first reflector is used to reflect the first light beam to the optical path deflection unit, and the second reflector is used to reflect the second light beam to the optical path deflection unit. The optical path deflection unit is used to change the transmission direction of the first beam and the second beam, and transmit the first beam and the second beam to the ring illumination shaping unit; The ring-shaped illumination shaping unit is used to modulate the first beam and the second beam into an arc shape and splice them into a ring-shaped illumination field of view to the object under test; The optical path transmission unit includes a convex reflector, and the ring illumination shaping unit includes a conical lens; The first beam and the second beam are diverged and reflected by the convex mirror to the conical lens, and the conical lens modulates the received beam into a ring-shaped illumination field of view; Alternatively, the optical path transmission unit includes a concave reflector, and the ring illumination shaping unit includes a spherical reflector group; The first beam and the second beam converge and reflect through the concave mirror to the spherical mirror group, which modulates the received beam into a ring-shaped illumination field of view.

2. The dark field ring lighting device according to claim 1, characterized in that, The convex reflector includes a first convex reflector and a second convex reflector, wherein the first convex reflector reflects the first light beam and the second convex reflector reflects the second light beam; or the convex reflector includes a hollow convex reflector, wherein both the first light beam and the second light beam are reflected by the hollow convex reflector.

3. The dark field ring lighting device according to claim 1, characterized in that, The concave reflector includes a first concave reflector and a second concave reflector, wherein the first concave reflector reflects the first light beam and the second concave reflector reflects the second light beam; or the concave reflector includes a hollow concave reflector, wherein both the first light beam and the second light beam are reflected by the hollow concave reflector. The spherical mirror assembly includes a central convex spherical mirror and a first concave spherical mirror and a second concave spherical mirror located on both sides of the central convex spherical mirror. The light reflected by the concave mirrors converges to the central convex spherical mirror, and the light reflected by the central convex spherical mirror forms an annular illumination field after being reflected by the first concave spherical mirror or the second concave spherical mirror.

4. The dark field ring lighting device according to claim 1, characterized in that, The number of the light source, the prism beam splitting unit and the optical path transmission unit is at least two. The ring illumination shaping unit modulates the output beams of at least two light sources into an arc shape and splices them into a ring illumination field of view to the object under test.

5. The dark field ring lighting device according to claim 1, characterized in that, It also includes a collimation and homogenization unit, which is located between the light source and the prism beam splitting unit. The illumination beam output by the light source is collimated by the collimation and homogenization unit and then incident on the prism beam splitting unit.

6. The dark field ring lighting device according to claim 1, characterized in that, It also includes an imaging optical path unit and a camera. The light scattered by the object under test is incident on the imaging optical path unit and converges to the imaging surface of the camera after passing through the imaging optical path unit.

7. The dark-field ring lighting device according to claim 6, characterized in that, The outer diameter of the imaging optical path unit is smaller than the minimum inner diameter of the optical path deflection unit and the annular illumination shaping unit, and the imaging optical path unit is surrounded by the optical path deflection unit and the annular illumination shaping unit.

8. An optical detection system, characterized in that, Includes the dark field ring lighting device as described in any one of claims 1 to 7.

Images