Optical system debugging method and optical detection system

Abstract

The invention provides an optical system debugging method and an optical detection system, and the method comprises the steps: firstly building an optical calibration system, and enabling an interferometer to receive a view field optical signal and a wave surface optical signal; secondly, the position of the calibration objective lens and the position of the second reflector can be quickly positioned by using the calibration through hole; thirdly, a calibration through hole is replaced by a calibration slit, so that the position precision when the focus of the objective lens coincides with the second reflector can be greatly improved; thirdly, the calibration objective lens is replaced by the detection objective lens, and on the premise that the position of the sphere center of the second reflector is determined, the focus of the detection objective lens can coincide with the sphere center of the second reflector; and finally, when the calibration objective lens is replaced, the detection objective lens is set to have a certain field angle, so that wave surface information generated by the high NA objective lens in a full field of view can be obtained. The device has the advantages of being simple in structure and convenient to operate.

Description

Technical Field

[0001] The invention relates to the field of optical measurement, and in particular to an optical system debugging method and an optical detection system. Background Art

[0002] In the semiconductor field, with the continuous development of science and technology, the demand for ultra-high precision instruments has also increased. For example, in the defect detection equipment in semiconductor manufacturing process equipment, in order to achieve the purpose of detecting smaller defects, it is often necessary to equip it with a high numerical aperture objective lens.

[0003] As an important component of semiconductor defect detection equipment, the quality of the objective lens will directly affect the performance of the entire equipment. In the manufacturing process of the objective lens, the precise measurement of the wavefront of the light signal after passing through the objective lens is crucial, which directly determines the ultimate resolution and detection accuracy of the defect detection equipment. Therefore, in order to ensure the overall quality of the semiconductor defect detection equipment, it is necessary to measure the wavefront information of the objective lens in the full field of view as accurately and quickly as possible to screen out the objective lens that meets the corresponding indicators, thereby improving the quality of the defect detection equipment.

[0004] The prior art generally adopts a Fizeau interferometer to measure the wavefront of the light signal after passing through the objective lens. The basic principle is that the spot of the parallel light after passing through the objective lens and converging to the focal point of the objective lens is aligned to the center of the sphere of the concave spherical reflector, and the concave spherical reflector reflects the light back to the objective lens, so as to ensure that the reflected light of the concave spherical reflector remains coaxial when returning to the interferometer, thereby generating clear interference fringes. However, due to the short working distance, shallow focal depth and small field of view of the high numerical aperture (NA) objective lens, aligning the focus of the objective lens with the center of the sphere of the concave spherical reflector is a time-consuming and difficult operation, so the measurement efficiency of the prior art is reduced. In addition, after aligning the center of the sphere with the focal point through cumbersome operations, the wavefront information under other fields of view of the objective lens is detected. Since the concave reflector is translated for detection, the axial movement of the displacement stage is at a certain angle to the optical axis of the interferometer and the displacement of each dimension of the displacement stage is coupled, so it is impossible to accurately and quantitatively measure the wavefront information under other fields of view of the objective lens.

[0005] Therefore, how to accurately and quantitatively measure the wavefront information of the objective lens in the full field of view has become one of the problems that technical personnel in this field need to solve urgently.

[0006] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention. Summary of the invention

[0007] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide an optical system debugging method and an optical detection system for solving the problem in the prior art that the wavefront information of the objective lens in the full field of view cannot be accurately and quantitatively measured.

[0008] To achieve the above-mentioned purpose and other related purposes, the present invention provides a debugging method for an optical system, which debugging method includes at least the following steps: S1: building an optical calibration system; the optical calibration system includes: an interferometer, a first reflector, a calibration objective lens and a second reflector; the interferometer sends an input light signal and transmits it to the first reflector and the calibration objective lens respectively; the first reflector is arranged in parallel with the calibration objective lens, and the first reflector reflects the first part of the input light signal back to the interferometer to obtain a field of view light signal; the optical axis of the calibration objective lens is parallel to the optical axis of the interferometer, and the calibration objective lens converges the second part of the input light signal and transmits it to the second reflector; the second reflector is a concave spherical reflector, and the second reflector converges the reflected light beam, and the converged reflected light beam passes through the calibration objective lens and returns to the interferometer to obtain a wavefront light signal; S2: using a calibration plate to debug the optical calibration system; the calibration objective lens A calibration plate is arranged between the calibration objective lens and the second reflector, and the plane where the calibration plate is located is perpendicular to the optical axis of the interferometer, and a calibration through hole and a calibration slit are arranged on the calibration plate; firstly, the position of the calibration through hole or the calibration objective lens is adjusted so that the focus of the calibration objective lens is arranged at the position of the calibration through hole; secondly, the position of the second reflector is adjusted so that the center of the sphere of the second reflector is arranged at the position of the calibration through hole; thirdly, the calibration through hole in the calibration optical system is replaced with the calibration slit, and the position of the calibration slit is adjusted so that the imaging center of the calibration slit in the interferometer coincides with the field of view center of the calibration objective lens; S3: the calibration objective lens of the calibration optical system is replaced with the detection objective lens, and the detection objective lens is moved along the optical axis of the interferometer so that the field of view center of the detection objective lens coincides with the imaging center of the calibration slit in the interferometer, and the calibration plate is withdrawn from the optical path to obtain the optical detection system.

[0009] Optionally, step S3 is replaced by step S3': replace the calibration objective lens of the calibration optical system with a detection objective lens, rotate the detection objective lens to form a field of view angle between the detection objective lens and the optical axis of the interferometer, and the first reflector and the detection objective lens always remain parallel; adjust the position of the detection objective lens so that the field of view center of the detection objective lens coincides with the imaging center of the calibration slit in the interferometer; remove the calibration plate from the light path, and obtain the optical detection system.

[0010] More optionally, in step S3', the detection objective lens is rotated in a three-dimensional coordinate system to form a field of view angle; the detection objective lens is translated in the three-dimensional coordinate system to adjust the position of the detection objective lens; wherein the three-dimensional coordinate system includes an X-axis, a Y-axis and a Z-axis, the Z-axis is the optical axis of the interferometer, the XY plane is a plane perpendicular to the Z-axis, and the X-axis and the Y-axis are any two mutually perpendicular straight lines in the XY plane and passing through the Z-axis.

[0011] Optionally, in step S2: first, translate the calibration through hole in the three-dimensional coordinate system to adjust the position of the calibration through hole, or translate the calibration objective lens along the Z axis to adjust the position of the calibration objective lens; secondly, translate the second reflector in the three-dimensional coordinate system to adjust the position of the second reflector; thirdly, translate the calibration slit in the XY plane to adjust the position of the calibration slit; wherein the three-dimensional coordinate system includes an X-axis, a Y-axis and a Z-axis, the Z-axis is the optical axis of the interferometer, the XY plane is a plane perpendicular to the Z-axis, and the X-axis and the Y-axis are any two mutually perpendicular straight lines in the XY plane and passing through the Z-axis.

[0012] Optionally, the field of view angle of the detection objective lens ranges from -6 degrees to +6 degrees.

[0013] Optionally, the numerical aperture of the calibration objective lens ranges from 0.055 to 0.42.

[0014] Optionally, the numerical aperture of the detection objective lens ranges from 0.42 to 0.9.

[0015] Optionally, the calibration through hole has a shape of any one of square, circle or pentagon.

[0016] Optionally, the calibration slit has an X-shape, a cross-shape or a cross-shape.

[0017] To achieve the above-mentioned purpose and other related purposes, the present invention provides an optical detection system, which is obtained based on the debugging method of the optical system, and the optical detection system at least includes: an interferometer, a detection objective lens, a first reflector and a second reflector; the interferometer sends an input light signal; the first reflector and the detection objective lens are arranged on the same side of the interferometer, and the first reflector and the detection objective lens are arranged in parallel; the first reflector reflects the first part of the input light signal back to the interferometer to obtain a field of view light signal; the detection objective lens converges the second part of the input light signal and transmits it to the second reflector; the second reflector is a concave spherical reflector, the second reflector generates a reflected light beam and converges the reflected light beam, and the converged reflected light beam passes through the detection objective lens and returns to the interferometer to obtain a wavefront light signal.

[0018] Optionally, the optical detection system also includes a total station; the optical axis of the total station is arranged parallel to the optical axis of the interferometer; the angle measurement light signal emitted by the total station is reflected by the first reflector and then returns to the total station, and the total station obtains the field of view angle of the detection objective lens based on the angle measurement light signal and the reflection signal of the angle measurement light signal.

[0019] Optionally, the first reflector is a plane reflector.

[0020] As described above, the optical system debugging method and optical detection system of the present invention have the following beneficial effects:

[0021] 1. The present invention locates the focus of the calibration objective lens and the center of the second reflector by means of a calibration through hole. Since the size accuracy of the calibration through hole is low, the present invention can quickly align the focus of the calibration objective lens and the center of the second reflector.

[0022] 2. The present invention replaces the calibration slit with a calibration through hole for positioning the focus of the calibration objective lens and the center of the second reflector. Since the dimensional accuracy of the calibration slit is much higher than that of the calibration through hole, the present invention can greatly improve the accuracy of aligning the focus of the calibration objective lens and the center of the second reflector, thereby greatly improving the accuracy of the wavefront light signal obtained by the interferometer.

[0023] 3. The present invention replaces the calibration objective lens with the detection objective lens. Since the calibration objective lens is usually a low NA objective lens and the detection objective lens is usually a high NA objective lens, on the premise that the focus of the calibration objective lens and the center of the second reflector have been quickly aligned, replacing the calibration objective lens with the detection objective lens can quickly achieve the purpose of aligning the focus of the detection objective lens with the center of the second reflector.

[0024] 4. The present invention sets a field of view angle between the detection objective lens and the interferometer optical axis, and adjusts the position of the detection objective lens so that the focus of the detection objective lens with the field of view angle coincides with the center of the second reflector. The present invention can obtain the wavefront information generated by the detection objective lens under the full field of view. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Shown is a schematic structural diagram of the optical calibration system of the present invention.

[0026] Figure 2 Shown is a schematic diagram of the flange surface of the calibration objective lens and the detection objective lens of the present invention.

[0027] Figure 3 It is a schematic diagram showing the debugging of the calibration plate of the present invention in the optical calibration system.

[0028] Figure 4 Shown is a first structural schematic diagram of the calibration plate of the present invention.

[0029] Figure 5It is a schematic diagram showing a second structure of the calibration plate of the present invention.

[0030] Figure 6 Shown is a third structural schematic diagram of the calibration plate of the present invention.

[0031] Figure 7 It is a schematic diagram showing the calibration of the second reflector and the calibration objective lens by the calibration plate of the present invention.

[0032] Figure 8 Shown is a schematic diagram of the three-dimensional coordinate system of the present invention.

[0033] Fig. 9 It is a schematic diagram showing the field of view angle of the detection objective lens and the interferometer optical axis of the present invention.

[0034] Fig.10 Shown is a schematic structural diagram of the optical detection system of the present invention.

[0035] Fig.11 It is a schematic diagram showing the debugging of the calibration plate of the present invention in an optical detection system.

[0036] Component number description

[0037] 1 Interferometer

[0038] 2 First reflector

[0039] 3 Calibration of the objective lens

[0040] 4 Second reflector

[0041] 5 Calibration plate

[0042] 5a Calibration through hole

[0043] 5b Calibration slit

[0044] 6. Detection lens

[0045] 7 Total Station DETAILED DESCRIPTION

[0046] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0047] See also Figure 1-Figure 11It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0048] Embodiment 1

[0049] like Figure 1 As shown, this embodiment provides a debugging method for an optical system, and the debugging method for an optical system includes the following steps:

[0050] like Figure 1 As shown, in step S1, an optical calibration system is constructed: the optical calibration system includes: an interferometer 1, a first reflector 2, a calibration objective lens 3 and a second reflector 4; the interferometer 1 sends an input light signal which is transmitted to the first reflector 2 and the calibration objective lens 3 respectively; the first reflector 2 is arranged in parallel with the calibration objective lens 3, and the first reflector 2 reflects a first part of the input light signal back to the interferometer 1 to obtain a field of view light signal; the optical axis of the calibration objective lens 3 is parallel to the optical axis of the interferometer 1, and the calibration objective lens 3 converges the second part of the input light signal and transmits it to the second reflector 4; the second reflector 4 is a concave spherical reflector, and the second reflector 4 converges the reflected light beam, and the converged reflected light beam passes through the calibration objective lens 3 and returns to the interferometer 1 to obtain a wavefront light signal.

[0051] Specifically, in this embodiment, the input optical signal of the interferometer 1 enters the first reflector 2 and the calibration objective lens 3 respectively; since the first reflector 2 and the calibration objective lens 3 are located on the same side of the interferometer 1, and as Figure 2 As shown, the plane where the first reflector 2 is located is parallel to the flange surface of the calibration objective lens 3, so the field of view of the first reflector 2 is consistent with the field of view of the calibration objective lens 3, and the interferometer 1 can obtain the field of view information of the calibration objective lens 3 based on the field of view light signal.

[0052] Specifically, in this embodiment, the second part of the input optical signal passes through the calibration objective lens 3 to the second reflector 4, and the second reflector 4 reflects the optical signal, and the reflected light beam passes through the calibration objective lens 3 to reach the interferometer 1; therefore, when the optical signal returns to the interferometer 1, the optical signal passes through two optical paths with the same route and opposite directions. By analyzing the wavefront optical signal, the interferometer 1 can obtain the wave aberration generated by the calibration objective lens 3 on the wavefront of the optical signal. Further, the calibration objective lens 3 is usually a low NA objective lens, because the low NA objective lens has a long working distance and a large field of view, which is conducive to quickly aligning the focus of the calibration objective lens 3 with the center of the sphere of the second reflector 4. As an example, the numerical aperture of the calibration objective lens 3 is 0.055 to 0.42, including but not limited to 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, and 0.4. Furthermore, the optical axis of the calibration objective lens 3 is kept parallel to the optical axis of the interferometer 1. The purpose is to ensure that the focus of the calibration objective lens 3 is always on a straight line parallel to the optical axis, to facilitate the alignment of the focus of the calibration objective lens 3 with the center of the sphere of the second reflector 4, and to facilitate the interferometer 1 to obtain the wave aberration generated at the center of the field of view of the calibration objective lens 3. In actual applications, the relative position relationship between the optical axis of the calibration objective lens 3 and the optical axis of the interferometer 1 is set as needed, which is not limited to this embodiment.

[0053] like Figure 3 As shown, in step S2, the optical calibration system is debugged using the calibration plate 5; the calibration plate 5 is arranged between the calibration objective lens 3 and the second reflector 4, and the plane where the calibration plate 5 is located is perpendicular to the optical axis of the interferometer 1, and the calibration plate 5 is provided with a calibration through hole 5a and a calibration slit 5b; firstly, the position of the calibration through hole 5a or the calibration objective lens 3 is adjusted so that the focus of the calibration objective lens 3 is set at the position of the calibration through hole 5a; secondly, the position of the second reflector 4 is adjusted so that the center of the sphere of the second reflector 4 is set at the position of the calibration through hole 5a; thirdly, the calibration through hole 5a in the calibration optical system is replaced by the calibration slit 5b, and the position of the calibration slit 5b is adjusted so that the imaging center of the calibration slit 5b in the interferometer 1 coincides with the field of view center of the calibration objective lens 3.

[0054] Specifically, in this embodiment, the plane where the calibration plate 5 is located is perpendicular to the optical axis of the interferometer 1, so that the calibration through hole 5a and the calibration slit 5b on the calibration plate 5 can quickly find the position of the focus of the calibration objective lens 3 (or the detection objective lens 6) and the center of the second reflector 4. Further, the calibration through hole 5a is used to preliminarily locate the focus of the calibration objective lens 3 and the center of the second reflector 4, so the size of the calibration through hole 5a is usually 1 mm to 2 mm, including but not limited to 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm; and, as Figure 4 , Figure 5 and Figure 6As shown, the shape of the calibration through hole 5a can be any one of square, circular or pentagonal. In practical applications, any hole shape that can allow the light signal at the focus of the objective lens and the light signal at the center of the reflector to pass through is applicable to the present invention, not limited to this embodiment. Furthermore, the calibration slit 5b is used to accurately locate the focus of the calibration objective lens 3 and the center of the second reflector 4, so the size of the calibration slit 5b is usually 5 microns to 10 microns, including but not limited to 5.5 microns, 6 microns, 6.5 microns, 7 microns, 7.5 microns, 8 microns, 8.5 microns, 9 microns, 9.5 microns; and, as Figure 4 , Figure 5 and Figure 6 As shown, the shape of the calibration slit 5b is any one of an X-shape, a cross shape or a cross shape. In practical applications, the shape combination of the calibration through hole 5a and the calibration slit 5b is selected on the calibration plate 5 as needed, and any slit shape whose symmetry center coincides with the slit intersection point is applicable to the present invention, and is not limited to this embodiment.

[0055] Specifically, in this embodiment, the purpose of first adjusting the calibration through hole 5a and the calibration objective lens 3 is to fix the position between the calibration objective lens 3 and the calibration through hole 5a so that the calibration through hole 5a and the focus of the calibration objective lens 3 coincide with each other. The method for adjusting the position of the calibration through hole 5a is to translate the calibration through hole 5a in the three-dimensional coordinate system, and the method for adjusting the position of the calibration objective lens 3 is to translate the calibration objective lens 3 along the Z axis. Further, as Figure 7 As shown, the calibration through hole 5a is used to make the center of the second reflector 4 coincide with the focus of the calibration objective lens 3, and the way to adjust the position of the second reflector 4 is to translate the second reflector 4 in the three-dimensional coordinate system. Furthermore, when the second reflector 4 and the calibration objective lens 3 have been debugged, the calibration through hole 5a is replaced with the calibration slit 5b. Since the position of the calibration through hole 5a on the Z axis has been determined, the position of the calibration slit 5b only needs to translate the calibration slit 5b in the XY plane. Furthermore, since the accuracy of the calibration slit 5b is relatively high, it is necessary to determine whether the imaging center of the calibration slit 5b in the interferometer coincides with the center of the field of view of the calibration objective lens 3, so that it can be considered that the center of the calibration slit 5b is located at the center of the overlap of the focus of the calibration objective lens 3 and the center of the second reflector 4.

[0056] Specifically, in this embodiment, the three-dimensional coordinate system includes an X-axis, a Y-axis and a Z-axis, the Z-axis is the optical axis of the interferometer, the XY plane is a plane perpendicular to the Z-axis, and the X-axis and the Y-axis are any two mutually perpendicular straight lines in the XY plane and passing through the Z-axis; as an example, Figure 8 As shown, the plane where the interferometer 1 emits the optical signal is set as the XY plane, and any two perpendicular lines in the XY plane and passing through the Z axis are set as the X axis and the Y axis. In practical applications, a three-dimensional coordinate system is set as needed, which is not limited to this embodiment.

[0057] like Figure 3 As shown, in step S3, the calibration objective lens 3 of the calibration optical system is replaced with the detection objective lens 6, and the detection objective lens 6 is moved along the optical axis of the interferometer 1 so that the field of view center of the detection objective lens 6 coincides with the imaging center of the calibration slit 5b in the interferometer 1, and the calibration plate 5 is withdrawn from the optical path to obtain the optical detection system.

[0058] Specifically, in this embodiment, under the premise that S1 and S2 have been debugged, the calibration lens 3 is replaced with the detection lens 6, such as Figure 2 As shown, the first reflector 2 is now parallel to the flange surface of the detection objective lens 6, wherein the detection objective lens 6 is usually a high NA objective lens, the numerical aperture of the detection objective lens 6 is greater than the numerical aperture of the calibration objective lens 3, and the numerical aperture of the detection objective lens 6 is usually 0.42 to 0.9, including but not limited to 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, and the purpose of replacement is to obtain the wavefront information generated by the high NA objective lens for the light signal. Further, on the premise that the calibration slit 5b has accurately positioned the position of the spherical center of the second reflector 4, the position of the detection objective lens 6 is adjusted again so that the focus of the detection objective lens 6 coincides with the spherical center of the second reflector 4. Since the detection objective lens 6 replaces the position of the calibration objective lens 3, the detection objective lens 6 has the same position and posture as the original calibration objective lens 3, so the detection objective lens 6 only needs to move along the optical axis of the interferometer 1 when adjusting the position. Furthermore, since the working distance of the detection objective lens 6 is relatively short and the accuracy of the calibration slit 5b is relatively high, it is necessary to observe and determine whether the imaging center of the calibration slit 5b in the interferometer coincides with the field of view center of the detection objective lens 6 (the first reflector 2 is always parallel to the detection objective lens 6), so that it can be considered that the focus of the detection objective lens 6 is accurately aligned with the center of the second reflector 4. Furthermore, after the focus of the detection objective lens 6 is aligned with the center of the second reflector 4, as shown in FIG. Fig. 9 As shown, the calibration plate 5 is removed from the optical path. At this time, the wavefront optical signal obtained by the interferometer 1 can accurately reflect the wave aberration caused by the detection objective lens 6 on the optical signal wavefront. That is, this embodiment obtains an optical detection system through the optical system debugging method.

[0059] Embodiment 2

[0060] The present embodiment provides a debugging method for an optical system. The difference between the present embodiment and the first embodiment is that step S3 is replaced by step S3': the calibration objective lens 3 of the calibration optical system is replaced by the detection objective lens 6, the detection objective lens 6 is rotated so that a field of view angle is formed between the detection objective lens 6 and the optical axis of the interferometer 1, and the first reflector 2 and the detection objective lens 6 are always kept parallel; the position of the detection objective lens 6 is adjusted so that the field of view center of the detection objective lens 6 coincides with the imaging center of the calibration slit 5b in the interferometer 1; the calibration plate 5 is withdrawn from the optical path to obtain the optical detection system.

[0061] Specifically, in this embodiment, the three-dimensional coordinate system includes an X-axis, a Y-axis and a Z-axis, wherein the Z-axis is the optical axis of the interferometer 1, the XY plane is a plane perpendicular to the Z-axis, and the X-axis and the Y-axis are any two mutually perpendicular straight lines in the XY plane and passing through the Z-axis. Further, the detection lens 6 is rotated around any straight line in the three-dimensional coordinate system so that the plane where the detection lens 6 is located forms a field of view angle θ with the Z-axis, as shown in FIG. Fig.10 As shown in FIG. 1 , the field of view angle θ is the angle between the plane where the detection lens 6 is located and the Z axis; in this process, the first reflector 2 is always kept parallel to the detection lens 6, so that the interferometer 1 can detect the field of view information of the detection lens 6. Furthermore, under the premise that the calibration slit 5b has accurately positioned the center of the second reflector 4, the position of the detection lens 6 is adjusted again, as shown in FIG. Fig.11 As shown, the focus of the detection objective lens 6 is made to coincide with the spherical center of the second reflector 4 (that is, the field of view center of the detection objective lens 6 coincides with the imaging center of the calibration slit 5b in the interferometer 1). Since there is a field of view angle between the detection objective lens 6 and the optical axis of the interferometer 1, the detection objective lens 6 needs to be translated in the three-dimensional coordinate system to adjust the position of the detection objective lens 6. Furthermore, after the focus of the detection objective lens 6 with the field of view angle is aligned with the spherical center of the second reflector 4, the calibration plate 5 is withdrawn from the optical path. At this time, the wavefront light signal obtained by the interferometer 1 can accurately reflect the wavefront aberration generated by the detection objective lens 6 on the light signal wavefront, that is, the optical detection system under the full field of view is obtained by the debugging method of the optical system in this embodiment.

[0062] Embodiment 3

[0063] like Fig. 9 As shown, this embodiment provides an optical detection system, which is obtained based on the debugging method of the optical system of Embodiments 1 to 2. The optical detection system at least includes: an interferometer 1, a detection objective lens 6, a first reflector 2 and a second reflector 4.

[0064] like Fig. 9 As shown, interferometer 1 sends an input optical signal.

[0065] Specifically, in this embodiment, the interferometer 1 can emit a light signal, that is, the interferometer 1 can be used as a light source. The light signal emitted by the interferometer 1 is a parallel light signal, and the purpose is to make the first input light signal better focused after passing through the objective lens; in addition, the interferometer 1 can also receive light signals and convert the light signals into electrical signals. The interferometer 1 can obtain field of view information by analyzing the field of view light signal, and can obtain the wavefront aberration caused by the objective lens on the wavefront of the light signal by analyzing the wavefront light signal output by the objective lens.

[0066] like Fig. 9As shown, the first reflector 2 and the detection objective lens 6 are arranged on the same side of the interferometer 1, and the first reflector 2 and the detection objective lens 6 are arranged in parallel; the first reflector 2 reflects the first part of the input light signal back to the interferometer 1 to obtain a field of view light signal.

[0067] Specifically, in this embodiment, the first reflector 2 is arranged in parallel with the detection lens 6 and is arranged on the same side of the interferometer 1, so the field of view light signal generated by the first reflector 2 can reflect the field of view of the detection lens 6. As an example, Figure 2 As shown, the first reflector 1 is installed at the lower edge of the detection objective lens 6 close to the interferometer 1, and the plane where the first reflector 1 is located is parallel to the flange surface of the detection objective lens 6 (such as Figure 2 As shown, the planes where the calibration objective lens 3 and the detection objective lens 6 are located refer to their respective flange surfaces), and the first reflector 2 adopts a plane reflector. In actual applications, the specific installation position and specific type of the first reflector 2 are selected according to needs, and are not limited to this embodiment.

[0068] like Fig. 9 As shown, the detection objective lens 6 gathers the second portion of light in the input light signal and transmits it to the second reflector 4 .

[0069] Specifically, in the present embodiment, the detection objective lens 6 focuses the light signal onto the focal point of the detection objective lens 6, and then the light signal continues to propagate to the second reflector 4. When the optical detection system is obtained by the debugging method of the optical system of the first embodiment, the field of view angle of the detection objective lens 6 is 0 degree. When the optical detection system is obtained by the debugging method of the optical system of the second embodiment, the field of view angle of the detection objective lens 6 can be [-6,0) degrees and (0,6] degrees, including but not limited to -5 degrees, -4 degrees, -3 degrees, -2 degrees, -1 degree, 1 degree, 2 degrees, 3 degrees, 4 degrees, and 5 degrees. The field of view angle can be positive when rotated clockwise and negative when rotated counterclockwise, or the field of view angle can also be negative when rotated clockwise and positive when rotated counterclockwise. In actual applications, the positive and negative of the field of view angle can be set as needed and is not limited to the present embodiment.

[0070] like Fig. 9 As shown, the second reflector 4 is a concave spherical reflector, which generates a reflected light beam and converges the reflected light beam. The converged reflected light beam passes through the detection objective lens 6 and then returns to the interferometer to obtain a wavefront light signal.

[0071] Specifically, in this embodiment, the second reflector 4 receives the light signal from the detection objective lens 6 and reflects it. The reflected light beam reflects the light signal to the center of the second reflector 4. Since the optical detection system is obtained through the debugging method of the optical system, the center of the second reflector 4 coincides with the focus of the detection objective lens 6. Then the light signal continues to pass through the detection objective lens 6 and return to the interferometer 1. The interferometer 1 can obtain an accurate wavefront light signal through the debugged detection objective lens 6 and the second reflector 4.

[0072] Embodiment 4

[0073] like Fig. 9 As shown, this embodiment provides an optical detection system. The difference between this embodiment and embodiment three is that: the optical detection system also includes a total station 7; the optical axis of the total station 7 is arranged parallel to the optical axis of the interferometer 1; the angle measurement light signal emitted by the total station 7 is reflected by the first reflector 2 and then returned to the total station 7, and the total station 7 obtains the field of view angle of the detection objective lens 6 based on the angle measurement light signal and the reflection signal of the angle measurement light signal.

[0074] Specifically, in this embodiment, when the detection objective lens 6 rotates in the three-dimensional coordinates, a viewing angle is formed between the detection objective lens 6 and the optical axis of the interferometer 1, and the first reflector 2 is always parallel to the detection objective lens 6; further, since the optical axis of the total station 7 is arranged in parallel with the optical axis of the interferometer 1, the angle between the first reflector 2 and the optical axis of the total station 1 is the angle between the flange surface of the detection objective lens 6 and the interferometer 1, that is, the viewing angle between the detection objective lens 6 and the interferometer 1 can be obtained by the total station 7 based on the light signal reflected by the first reflector 2. In practical applications, a specific device for measuring the viewing angle between the detection objective lens 6 and the optical axis of the interferometer 1 is provided as needed, which is not limited to this embodiment.

[0075] In summary, the debugging method of the optical system of the present invention first builds a bidirectional optical path between the interferometer, the calibration objective lens and the second reflector; secondly, the present invention can quickly make the calibration objective lens focus and the second reflector center coincide with each other by using the calibration through hole to quickly locate the calibration objective lens focus and the second reflector center; thirdly, the present invention can greatly improve the position accuracy when the objective lens focus coincides with the second reflector by replacing the calibration through hole with lower dimensional accuracy with the calibration slit with higher dimensional accuracy, thereby improving the accuracy of the wavefront information generated by the objective lens; thirdly, the present invention replaces the calibration objective lens with the detection objective lens, and on the premise that the calibration objective lens focus and the second reflector center are aligned, the position of the detection objective lens can be quickly adjusted to make the focus of the detection objective lens coincide with the center of the second reflector, thereby obtaining accurate wavefront information generated by the detection objective lens; finally, when replacing the calibration objective lens, the present invention sets the detection objective lens to have a certain field of view angle, and makes the focus of the detection objective lens coincide with the center of the second reflector, so that the present invention can obtain the wavefront information generated by the detection objective lens under the full field of view. Finally, the calibration plate is withdrawn from the optical path, and the present invention can obtain an optical detection system that can accurately measure the wavefront information generated by the objective lens. In addition, the present invention has the advantages of quick operation and simple structure. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0076] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for debugging an optical system, characterized in that: The debugging method of the optical system comprises at least the following steps: S1: Build an optical calibration system; the optical calibration system includes: an interferometer, a first reflector, a calibration objective lens and a second reflector; the interferometer sends an input light signal which is transmitted to the first reflector and the calibration objective lens respectively; the first reflector is arranged in parallel with the calibration objective lens, and the first reflector reflects the first part of the input light signal back to the interferometer to obtain a field of view light signal; the optical axis of the calibration objective lens is parallel to the optical axis of the interferometer, and the calibration objective lens converges the second part of the input light signal and transmits it to the second reflector; the second reflector is a concave spherical reflector, and the second reflector converges the reflected light beam, and the converged reflected light beam passes through the calibration objective lens and returns to the interferometer to obtain a wavefront light signal; S2: Use a calibration plate to debug the optical calibration system; the calibration plate is arranged between the calibration objective lens and the second reflector, and the plane where the calibration plate is located is perpendicular to the optical axis of the interferometer, and a calibration through hole and a calibration slit are arranged on the calibration plate; first, adjust the position of the calibration through hole or the calibration objective lens so that the focus of the calibration objective lens is set at the position of the calibration through hole; secondly, adjust the position of the second reflector so that the center of the sphere of the second reflector is set at the position of the calibration through hole; thirdly, use the calibration slit to replace the calibration through hole in the calibration optical system, and adjust the position of the calibration slit so that the imaging center of the calibration slit in the interferometer coincides with the field of view center of the calibration objective lens; S3: Replace the calibration objective lens of the calibration optical system with a detection objective lens, the field of view angle between the detection objective lens and the optical axis of the interferometer is 0 degrees, and the detection objective lens is moved along the optical axis of the interferometer so that the field of view center of the detection objective lens coincides with the imaging center of the calibration slit in the interferometer, and the calibration plate is removed from the optical path to obtain the optical detection system.

2. The debugging method of the optical system according to claim 1, characterized in that: Replace step S3 with step S3': replace the calibration objective lens of the calibration optical system with the detection objective lens, rotate the detection objective lens to form a field of view angle between the detection objective lens and the optical axis of the interferometer, and the first reflector and the detection objective lens always remain parallel; adjust the position of the detection objective lens so that the field of view center of the detection objective lens coincides with the imaging center of the calibration slit in the interferometer; remove the calibration plate from the light path, and obtain the optical detection system.

3. The debugging method of the optical system according to claim 2, characterized in that: In step S3', the detection objective lens is rotated in a three-dimensional coordinate system to form a field of view angle; the detection objective lens is translated in the three-dimensional coordinate system to adjust the position of the detection objective lens; wherein the three-dimensional coordinate system includes an X-axis, a Y-axis and a Z-axis, the Z-axis is the optical axis of the interferometer, the XY plane is a plane perpendicular to the Z-axis, and the X-axis and the Y-axis are any two mutually perpendicular straight lines in the XY plane and passing through the Z-axis.

4. The debugging method of the optical system according to claim 1 or 2, characterized in that: In step S2: First, the calibration through hole is translated in a three-dimensional coordinate system to adjust the position of the calibration through hole, or the calibration objective lens is translated along the Z axis to adjust the position of the calibration objective lens; Secondly, translating the second reflector in a three-dimensional coordinate system to adjust the position of the second reflector; Thirdly, translating the calibration slit in the XY plane to adjust the position of the calibration slit; The three-dimensional coordinate system includes an X-axis, a Y-axis and a Z-axis, the Z-axis is the optical axis of the interferometer, the XY plane is a plane perpendicular to the Z-axis, and the X-axis and the Y-axis are any two perpendicular straight lines in the XY plane that pass through the Z-axis.

5. The debugging method of the optical system according to claim 1 or 2, characterized in that: The viewing angle of the detection objective lens ranges from -6 degrees to +6 degrees.

6. The debugging method of the optical system according to claim 1 or 2, characterized in that: The numerical aperture of the calibration objective lens ranges from 0.055 to 0.

42.

7. The debugging method of the optical system according to claim 1 or 2, characterized in that: The numerical aperture of the detection objective lens ranges from 0.42 to 0.

9.

8. The debugging method of an optical system according to claim 1 or 2, characterized in that: The shape of the calibration through hole is any one of square, circle or pentagon.

9. The debugging method of an optical system according to claim 1 or 2, characterized in that: The shape of the calibration slit is any one of an X-shape, a cross-shape or a cross-shape.

10. An optical detection system, obtained based on the debugging method of an optical system according to any one of claims 1 to 9, the optical detection system at least comprising: An interferometer, a detection objective lens, a first reflecting mirror and a second reflecting mirror; The interferometer sends an input optical signal; The first reflector and the detection objective lens are arranged on the same side of the interferometer, and the first reflector and the detection objective lens are arranged in parallel; the first reflector reflects a first portion of light in the input light signal back to the interferometer to obtain a field of view light signal; The detection objective lens gathers the second portion of light in the input light signal and transmits it to the second reflector; The second reflector is a concave spherical reflector, which generates a reflected light beam and converges the reflected light beam. The converged reflected light beam passes through the detection objective lens and then returns to the interferometer to obtain a wavefront light signal.

11. The optical detection system according to claim 10, characterized in that: The optical detection system also includes a total station; the optical axis of the total station is arranged parallel to the optical axis of the interferometer; the angle measurement light signal emitted by the total station is reflected by the first reflector and then returned to the total station, and the total station obtains the field of view angle of the detection objective lens based on the angle measurement light signal and the reflection signal of the angle measurement light signal.

12. The optical detection system according to claim 10, characterized in that: The first reflector is a plane reflector.

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