Optical detection device and optimal focal plane determination method, medium

Abstract

The application discloses an optical detection device, a method for determining an optimal focal plane of the optical detection device, and a medium. The optical detection device comprises at least an illumination module, a stage, an interference module, a target area selection module, and an imaging module. The method for determining the optimal focal plane of the optical detection device comprises a debugging stage, a training stage, and a detection stage. In the debugging stage, the position of the stage and the position of the target area selection module are adjusted when the illumination module emits an illumination beam, so that the sample is located at the center of the field of view of the imaging module and the center of the target area selection module coincides with the center of the field of view. In the training stage, the system focusing deviation of the optical detection device is obtained after the sample is located at the center of the field of view of the imaging module and the center of the target area selection module coincides with the center of the field of view. In the detection stage, the optimal focal plane is determined according to the system focusing deviation and the interference signal obtained by the interference module, so that the determination rate and accuracy of the optimal focal plane are improved.

Description

Technical Field

[0001] This invention relates to the field of optical inspection technology, and in particular to an optical inspection device and its optimal focal plane determination method and medium. Background Technology

[0002] In recent years, with the deepening and popularization of industrial automation and intelligence, the use of automated optical inspection (AOI) equipment to replace traditional manual visual inspection has become a technological development trend. AOI equipment, with its fast and accurate defect identification and location capabilities, is widely used in the automotive, pharmaceutical, transportation, and semiconductor industries.

[0003] Currently, existing AOI equipment typically includes an optical imaging module, a stage, and a material transfer system. The optical imaging module includes an illumination unit, an imaging lens, and a detector. During AOI inspection, the surface to be measured needs to be adjusted to the optimal focal plane to obtain a clear image for easy identification of defects. Generally, existing technologies use an optical system and interferometry to measure sample height, primarily by moving a vertical optical device to change the distance between the optical acquisition device and the sample. A white light interference signal is acquired through a light intensity detector. However, this white light interference signal pertains to the entire field of view, while the proportion of the target within the entire field of view is uncertain, making it impossible to analyze the interference signal of a local sample. Furthermore, the background interference around the target is often very strong, causing the focal plane of the white light interferometry measurement to be constrained by the inconsistency of the background around the target. When facing different targets, the focal plane of the white light interferometry measurement is often constrained by the inconsistency of different targets, resulting in poor focusing performance.

[0004] Against this backdrop, improving the speed and accuracy of determining the optimal focal plane of optical inspection equipment has become a current technical challenge. Summary of the Invention

[0005] This invention provides an optical detection device and a method and medium for determining the optimal focal plane, so as to improve the determination speed and accuracy of the optimal focal plane.

[0006] In a first aspect, the present invention provides a method for determining the optimal focal plane of an optical detection device, the optical detection device comprising at least: an illumination module, a stage, an interference module, a target region selection module, and an imaging module, wherein the illumination module is used to emit an illumination beam, the stage is used to place a sample, the interference module is used to acquire interference signals of the sample image, the target region selection module is used to adjust the sample image acquired by the imaging module or the interference module, and the imaging module is used to acquire the sample image.

[0007] The method for determining the optimal focal plane of the optical detection device includes a debugging phase, a training phase, and a detection phase.

[0008] During the debugging phase, when controlling the illumination module to emit an illumination beam, the position of the stage and the position of the target area selection module are adjusted so that the sample is located at the center of the field of view of the imaging module and the center of the target area selection module coincides with the center of the field of view.

[0009] During the training phase, after the sample is located at the center of the field of view of the imaging module and the center of the target region selection module coincides with the center of the field of view, the system focusing deviation of the optical detection device is obtained.

[0010] During the detection phase, the optimal focal plane is determined based on the system focusing deviation and the interference signal acquired by the interference module.

[0011] Optionally, when the illumination module emits an illumination beam, the position of the stage and the position of the target area selection module are adjusted so that the sample is located at the center of the field of view of the imaging module and the light transmission center of the target area selection module coincides with the center of the field of view, including:

[0012] The optical detection device is controlled to perform the imaging process, and the position of the stage relative to the center of the field of view is adjusted so that the sample is located at the center of the field of view of the imaging module.

[0013] When the sample is located at the center of the field of view of the imaging module, the optical detection device is controlled to perform a calibration process to adjust the position of the target area selection module in the optical detection device so that the light transmission center of the target area selection module coincides with the center of the field of view.

[0014] The process of the sample reflecting the illumination beam to the imaging module when the illumination beam emitted by the illumination module does not pass through the target area selection module and illuminates the sample surface is the imaging process; the process of the sample reflecting the illumination beam to the imaging module when the illumination beam emitted by the illumination module passes through the target area selection module and illuminates the sample surface is the calibration process.

[0015] Optionally, obtaining the system focusing deviation of the optical detection device includes:

[0016] The optical detection device is controlled to perform the imaging process, and the distance between the stage and the imaging module is adjusted so that the imaging module acquires multiple sample images;

[0017] Based on each of the sample images, the first focal plane of the optical detection device is determined;

[0018] The optical detection device is controlled to perform an interference process, and the distance between the stage and the imaging module is adjusted so that the interference module acquires multiple interference signals;

[0019] The second focal plane of the optical detection device is determined based on each of the interference signals.

[0020] The system focusing deviation is determined based on the first focal plane and the second focal plane;

[0021] The process of the sample reflecting the illumination beam to the imaging module when the illumination beam emitted from the illumination module does not pass through the target area selection module and illuminates the sample surface is the imaging process; the process of the sample reflecting the illumination beam and the interference reflection beam from the interference module being incident on the imaging module is the interference process.

[0022] Optionally, the system focusing deviation is determined based on the first focal plane and the second focal plane, including:

[0023] The difference between the first focal plane and the second focal plane is taken as the focusing deviation of the system.

[0024] Optionally, the optimal focal plane is determined based on the system focusing deviation and the interference signal acquired by the interference module, including:

[0025] The target detection sample is placed on the stage, the optical detection device is controlled to perform the interference process, and the distance between the stage and the imaging module is adjusted so that the interference module acquires multiple interference signals.

[0026] The target sample height of the stage is determined based on the interference signals described above.

[0027] The optimal focal plane is determined based on the target sample height and the system focusing deviation.

[0028] The process in which the illumination beam emitted by the illumination module illuminates the sample surface and the interference module after passing through the target area selection module, and the sample reflection beam after the sample reflects the illumination beam and the interference reflection beam after the interference module reflects the illumination beam are incident on the imaging module, is called the interference process.

[0029] Optionally, determining the optimal focal plane based on the target sample height and the system focusing deviation includes:

[0030] The sum of the target sample height and the system focusing deviation is taken as the optimal focal plane.

[0031] In a second aspect, the present invention provides an optical detection device, which includes at least an illumination module, a stage, an interference module, a target area selection module, an imaging module, and a controller;

[0032] The lighting module includes at least a lighting source, and the lighting module is used to emit a lighting beam;

[0033] The stage is used to place the sample;

[0034] The imaging module includes an objective lens, a first beam splitter, a second beam splitter, a third lens, and a camera. The imaging module is used to acquire sample images.

[0035] The interference module includes a first shutter, a first lens, a reference mirror, a second lens, and a light intensity collector. The first lens is located in the optical path between the first shutter and the reference mirror, and the second lens is located in the optical path between the second beam splitter and the light intensity collector. The interference module is used to acquire interference signals.

[0036] The target region selection module includes at least a light-shielding component, and the target region selection module is used to adjust the sample image acquired by the imaging module or the interference module;

[0037] The controller is electrically connected to the camera, the target area selection module, and the interference module, respectively, and is used to execute the optimal focal plane determination method of the optical detection device described in the first aspect.

[0038] Optionally, when the target area selection module is located in the optical path between the illumination module and the first beam splitter, the target area selection module further includes a fourth lens and a fifth lens;

[0039] The fourth lens is located in the optical path between the illumination module and the light-shielding component, and the fifth lens is located in the optical path between the light-shielding component and the first beam splitter.

[0040] Optionally, when the target area selection module is located in the optical path between the second lens and the light intensity collector, the light-shielding component includes a light-shielding plate or a field aperture.

[0041] The light-shielding sheet includes multiple light-shielding areas, and the light transmittance of each light-shielding area is adjustable.

[0042] Thirdly, the present invention provides a computer-readable storage medium storing computer instructions for causing a processor to execute the optimal focal plane determination method of the optical detection device described in the first aspect.

[0043] The technical solution provided by this invention adjusts the position of the stage and the target area selection module during the debugging phase when controlling the illumination module to emit the illumination beam. This ensures that the sample is located at the center of the field of view of the imaging module and that the center of the target area selection module coincides with the center of the field of view. Then, a training phase is initiated to obtain the system focusing deviation of the optical detection device. This allows the optimal focal plane to be determined during the detection phase after the target sample is placed on the stage, based on the system focusing deviation and the interference signal obtained by the interference module. Thus, when detecting multiple target samples of the same type, only one target sample needs to undergo the detection phase to obtain the optimal focal plane for that type of target sample, eliminating the need to perform the detection phase on all target samples. This improves the speed and accuracy of determining the optimal focal plane. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of an optical detection device provided in Embodiment 1 of the present invention;

[0045] Figure 2 This is a schematic diagram of another optical detection device provided in Embodiment 1 of the present invention;

[0046] Figure 3 This is a schematic diagram of the structure of another optical detection device provided in Embodiment 1 of the present invention;

[0047] Figure 4 This is a schematic diagram of the structure of another optical detection device provided in Embodiment 1 of the present invention;

[0048] Figure 5 This is a flowchart of a method for determining the optimal focal plane of an optical detection device according to Embodiment 2 of the present invention;

[0049] Figure 6 This is a flowchart of a method for determining the optimal focal plane of an optical detection device according to Embodiment 3 of the present invention;

[0050] Figure 7 This is a schematic diagram of the structure of a sample provided in Embodiment 3 of the present invention;

[0051] Figure 8 This is a curve showing the relationship between beam intensity and the position of the field stop provided in Embodiment 3 of the present invention;

[0052] Figure 9 This is a flowchart of a method for determining the optimal focal plane of an optical detection device according to Embodiment 4 of the present invention;

[0053] Figure 10 This is a flowchart of a method for determining the optimal focal plane of an optical detection device according to Embodiment 5 of the present invention. Detailed Implementation

[0054] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0055] Example 1

[0056] Figure 1 This is a schematic diagram of the structure of an optical detection device provided in Embodiment 1 of the present invention. Figure 2 This is a schematic diagram of another optical detection device provided in Embodiment 1 of the present invention. Figure 3 This is a schematic diagram of the structure of another optical detection device provided in Embodiment 1 of the present invention. Figure 4 This is a schematic diagram of another optical detection device provided in Embodiment 1 of the present invention, with reference to... Figures 1-4 The optical detection device includes at least an illumination module 10, a stage 2, an interference module 58, a target area selection module 70, an imaging module 80, and a controller (not shown in the figure); the illumination module 10 includes at least an illumination source 101, which is used to emit an illumination beam; the stage 2 is used to place the sample 3; the imaging module 80 includes an objective lens 4, a first beam splitter 6, a second beam splitter 801, a third lens 804, and a camera 805, which is used to acquire sample images; the interference module 58 includes a first shutter 503, a first lens 502, a reference mirror 501, a second lens 802, and a light intensity sensor. The collector 803 has a first lens 502 located in the optical path between the first shutter 503 and the reference mirror 501, and a second lens 802 located in the optical path between the second beam splitter 801 and the light intensity collector 803. The interference module 58 is used to acquire interference signals. The target area selection module 70 includes at least a light-shielding component 74 and is used to adjust the sample image acquired by the imaging module 80 or the interference module 58. The controller is electrically connected to the camera 805, the target area selection module 70, and the interference module 58, and is used to execute the optimal focal plane determination method of the optical detection device provided in any embodiment of the present invention.

[0057] The illumination source 101 includes at least a laser source, and may also include a lens 102 and an attenuator 103. The illumination beam emitted from the illumination source 10 passes through the lens 102 and is then projected as a parallel beam to the attenuator 103. The attenuator 103 adjusts the intensity of the parallel beam, reduces noise, and improves the stability of the beam during transmission. The specific structure of the illumination module 10 can also be other, and is not specifically defined here. The stage 2 is used to place or support the sample 3, which includes a wafer or other devices. The imaging module 80 is used to acquire the imaging beam formed by the reflection of the illumination beam from the sample 3 to generate a sample image. The first shutter 503 includes a photoelectric shutter or a mechanical shutter, which can be selected according to actual needs, and is not specifically limited here.

[0058] It is understandable that the target area selection module 70 can be set according to actual needs. For example, it can be located on the optical path between the illumination module 10 and the first beam splitter, or on the optical path between the second lens and the light intensity collector. No specific limitation is made here.

[0059] In an alternative embodiment, such as Figure 1 As shown, when the target area selection module 70 is located on the optical path between the illumination module 10 and the first beam splitter 6, the target area selection module 70 further includes a fourth lens 703 and a fifth lens 705; the fourth lens 703 is located on the optical path between the illumination module 10 and the light-shielding component 74, and the fifth lens 705 is located on the optical path between the light-shielding component 704 and the first beam splitter 6. The optical detection device also includes a second shutter 702 and a third shutter 701.

[0060] Specifically, when the third shutter 701 is open and the second shutter 702 is closed, the illumination beam emitted by the illumination module 10 is emitted through the third shutter 701 and onto the incident surface of the first beam splitter 6; when the second shutter 702 is open and the third shutter 701 is closed, the illumination beam emitted by the illumination module 10 is emitted through the second shutter 702, the fourth lens 703, the light-shielding component 74 and the fifth lens 705 and onto the incident surface of the first beam splitter 6.

[0061] Specifically, when the optical detection device performs the shooting process, it controls the first shutter 503 to close. The illumination beam emitted from the illumination source 101 passes through the lens 102 and the attenuator 103 and then enters the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the incident beam to the sample 3. The imaging beam reflected by the sample 3 passes through the first beam splitter 6, the second beam splitter 801 and the lens 804 in sequence and enters the camera 805 to form an image, thereby generating a sample image.

[0062] When the optical detection device performs the calibration process, it controls the first shutter 503 and the third shutter 701 to close and the second shutter 702 to open. The illumination beam emitted from the illumination module 10 passes through the second shutter 702, the fourth lens 703, the light-shielding component 74 and the fifth lens 705 and is incident on the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the beam emitted from the target area selection module 70 to the sample 3. The imaging beam reflected by the sample 3 passes through the first beam splitter 6, the second beam splitter 801 and the lens 804 in sequence and is incident on the camera 805 to form an image, thereby generating a sample image.

[0063] When the optical detection device performs the interference process, it controls the third shutter 701 to close and the first shutter 503 and second shutter 702 to open. The illumination beam emitted from the illumination module 10 passes through the second shutter 702, the fourth lens 703, the light-shielding component 74, and the fifth lens 705 and is incident on the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the beam emitted from the target area selection module 70 onto the sample 3, and the imaging beam reflected by the sample 3 is incident on the first beam splitter 6. At the same time, the first beam splitter 6 also reflects the beam emitted by the target area selection module 70 onto the sample 3. The light beam emitted from 70 is transmitted to the reference mirror 501. After being reflected by the light spot on the reference mirror 501, it passes through the first lens 502 and the first shutter 503 in sequence and enters the first beam splitter 6. The imaging beam reflected by the sample 3 and the beam reflected by the reference mirror 501 interfere at the first beam splitter 6 to generate an interference beam. After being reflected by the second beam splitter 801, the interference beam passes through the second lens 802 and enters the light intensity collector 803. The light intensity collector 803 can acquire the interference beam and process it to obtain the interference signal.

[0064] In another alternative embodiment, such as Figure 2 As shown, when the target area selection module 70 is located in the optical path between the illumination module 10 and the first beam splitter 6, the target area selection module 70 also includes a fourth lens 703 and a fifth lens 705; the fourth lens 703 is located in the optical path between the illumination module 10 and the light-shielding component 74, and the fifth lens 705 is located in the optical path between the light-shielding component 704 and the first beam splitter 6.

[0065] Specifically, when the optical detection device performs the shooting or calibration process, it controls the first shutter 503 to close. The illumination beam emitted from the illumination module 10 passes through the fourth lens 703, the light-shielding component 74, and the fifth lens 705 and is incident on the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the beam emitted from the target area selection module 70 to the sample 3. The imaging beam reflected by the sample 3 passes through the first beam splitter 6, the second beam splitter 801, and the lens 804 in sequence and is incident on the camera 805 to form an image, thereby generating a sample image.

[0066] When the optical detection device performs the interference process, it controls the first shutter 503 to open. The illumination beam emitted from the illumination module 10 passes through the fourth lens 703, the light-shielding component 74, and the fifth lens 705 and is incident on the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the beam emitted from the target area selection module 70 to the sample 3. The imaging beam reflected by the sample 3 is incident on the first beam splitter 6. At the same time, the first beam splitter 6 also transmits the beam emitted from the target area selection module 70 to the reference mirror 501. The light spot on the reference mirror 501 is reflected and passes through the first lens 502 and the first shutter 503 in sequence before being incident on the first beam splitter 6. The imaging beam reflected by the sample 3 and the beam reflected by the reference mirror 501 interfere at the first beam splitter 6 to generate an interference beam. The interference beam is reflected by the second beam splitter 801 and then passes through the second lens 802 into the light intensity collector 803. The light intensity collector 803 can acquire the interference beam and process it to obtain the interference signal.

[0067] It should be noted that the light-shielding component 74 includes a light-shielding sheet 704 ( Figure 1 ) or field stop 708 ( Figure 2 The shape and size of the light-shielding plate 704 can be consistent with that of sample 3. For example, sample 3 is a circular structure with a radius of 2cm, and the light-shielding plate 704 is also a circular structure with a radius of 2cm. The light transmittance of each region in the light-shielding plate 704 can be the same or different. When the light transmittance of the central region is 100%, and the light transmittance of other regions around the central region gradually decreases or all become 0%, the size of the sample image acquired by the camera 805 is consistent with the size of the central region. Thus, the size or dimensions of the sample image can be adjusted by adjusting the light transmittance of each region of the light-shielding plate 704. The structure of the light-shielding plate 704 can also be other, and no specific limitation is made here. The field stop 708 is used to limit the range of object imaging. The larger the aperture angle of the field stop 708, the larger the range of object imaging.

[0068] In another optional embodiment, when the target area selection module 70 is located in the optical path between the second lens 802 and the light intensity collector 803, the light-shielding component 74 includes a light-shielding plate 704. Figure 3 ) or field stop 708 ( Figure 4 ).

[0069] Among them, the light-blocking sheet 704 includes multiple light-blocking areas, and the light transmittance of each light-blocking area is adjustable.

[0070] Specifically, when the optical detection device performs the shooting or calibration process, it controls the first shutter 503 to close, and the illumination beam emitted from the illumination module 10 is incident on the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the beam emitted from the target area selection module 70 to the sample 3. The imaging beam reflected by the sample 3 passes through the first beam splitter 6, the second beam splitter 801 and the lens 804 in sequence and is incident on the camera 805 to form an image, thereby generating a sample image. At the same time, the second beam splitter 801 reflects the light emitted from the first beam splitter 6 and passes through the second lens 802 and the light component 74 to be incident on the light intensity collector 803 so that the light intensity collector 803 can acquire the light intensity signal.

[0071] When the optical detection device performs the interference process, it controls the first shutter 503 to open, and the illumination beam emitted from the illumination module 10 is incident on the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the beam emitted from the target area selection module 70 to the sample 3, and the imaging beam reflected by the sample 3 is incident on the first beam splitter 6. At the same time, the first beam splitter 6 also transmits the beam emitted from the target area selection module 70 to the reference mirror 501. After the light spot on the reference mirror 501 is reflected, it passes through the first lens 502 and the first shutter 503 in sequence and is incident on the first beam splitter 6. The imaging beam reflected by the sample 3 and the beam reflected by the reference mirror 501 interfere at the first beam splitter 6 to generate an interference beam. After being reflected by the second beam splitter 801, the interference beam passes through the second lens 802 and enters the light intensity collector 803. The light intensity collector 803 can acquire the interference beam and process it to obtain the interference signal.

[0072] The technical solution of this invention involves setting up an illumination module, a stage, an interference module, a target area selection module, an imaging module, and a controller in an optical detection device. The illumination module includes at least an illumination source and is used to emit an illumination beam. The stage is used to place a sample. The imaging module includes an objective lens, a first beam splitter, a second beam splitter, a third lens, and a camera, and is used to acquire sample images. The interference module includes a first shutter, a first lens, a reference mirror, a second lens, and a light intensity collector. The first lens is located in the optical path between the first shutter and the reference mirror, and the second lens is located in the optical path between the second beam splitter and the light intensity collector. The interference module is used to acquire interference signals. The target area selection module includes at least a light-shielding component and is used to adjust the sample image acquired by the imaging module or the interference module. The controller is electrically connected to the camera, the target area selection module, and the interference module, respectively, and is used to execute the optimal focal plane determination method of the optical detection device provided in any embodiment of this invention to improve the accuracy of the optimal focal plane.

[0073] Example 2

[0074] Figure 5This is a flowchart illustrating a method for determining the optimal focal plane of an optical detection device according to Embodiment 2 of the present invention. This method is applicable to determining the optimal focal plane of an optical detection device, and the optimal focal plane can be determined by the optical detection device provided in this embodiment of the invention. This optical detection device can be implemented in hardware and / or software. Figure 5 As shown, the method for determining the optimal focal plane of this optical detection device includes:

[0075] S101. During the debugging phase, when controlling the illumination module to emit the illumination beam, adjust the position of the stage and the position of the target area selection module so that the sample is located at the center of the field of view of the imaging module and the light transmission center of the target area selection module coincides with the center of the field of view.

[0076] The debugging phase mainly involves adjusting the positions of relevant components in the optical detection device.

[0077] It should be noted that the embodiments of the present invention can employ... Figures 1-4 Performed by any of the optical detection devices shown herein, and for ease of description, all will be referred to as such below. Figure 1 The optical detection device shown in the diagram will be used as an example for illustration. Figure 2 , Figure 3 or Figure 4 The principle of how the optical detection device in the text performs this method can be referenced from [the relevant documentation / reference]. Figure 1 Explanation of the principle of the optical detection device.

[0078] For details, please refer to Figure 1When controlling the illumination module to emit the illumination beam, the order in which the positions of the stage and the target area selection module are adjusted can be set according to actual needs. For example, taking the adjustment of the stage position first as an example, the second shutter 702 and the first shutter 503 are closed, and the third shutter 701 is opened. The illumination beam emitted by the illumination module 10 is incident on the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the incident beam to the sample 3. The sample 3 reflects the imaging beam, which passes through the first beam splitter 6, the second beam splitter 801, and the lens 804 in sequence and is incident on the camera 805 to generate a sample image. Based on the sample image, the stage 2 is adjusted to move in a direction perpendicular to the incident optical axis of the camera so that the sample is located at the center of the field of view of the imaging module. Then, the third shutter 701 and the first shutter 503 are closed, and the second shutter 702 is opened. The illumination beam emitted by the illumination module 10 passes through the target area selection module 70 and is incident on the first beam splitter 805. The first beam splitter 6 reflects the light beam emitted from the target area selection module 70 to the sample 3. The imaging beam reflected from the sample 3 passes sequentially through the first beam splitter 6, the second beam splitter 801, and the lens 804 and is incident into the camera 805 to generate a sample image. The light transmittance of the central area of ​​the light-shielding component in the target area selection module 70 can be adjusted to be greater than that of the surrounding area. This allows the position of the light transmission center of the target area selection module in the field of view of the imaging module 80 to be determined through the sample image. Based on the relative position of the light transmission center of the target area selection module in the field of view of the imaging module, the position of the target area selection module can be adjusted so that the light transmission center of the target area selection module coincides with the center of the field of view of the imaging module. This eliminates the need to adjust the position of the stage in the direction perpendicular to the incident optical axis of the camera and the position of the target area selection module during the subsequent determination of the optimal focal plane, thereby improving the efficiency of obtaining the optimal focal plane.

[0079] S102. During the training phase, after the sample is located at the center of the field of view of the imaging module and the center of the target region selection module coincides with the center of the field of view, the system focusing deviation of the optical detection device is obtained.

[0080] Here, the system focus deviation represents the height difference between the first focal plane corresponding to the clear sample image acquired by the imaging module and the second focal plane corresponding to the preset interference signal acquired by the interferometer module. In practical sample detection applications, since the samples being detected have strong consistency, that is, the interference fringes produced by each sample are basically similar, it can be assumed that the system focus deviation of all samples is the same. Once the system focus deviation is determined through one sample, it can be applied to the detection of all samples, simplifying the detection process.

[0081] For details, please refer to Figure 1When the illumination module emits an illumination beam, the second shutter 702 and the first shutter 503 are closed, and the third shutter 701 is opened. The illumination beam emitted by the illumination module 10 is incident on the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the incident beam onto the sample 3. The reflected imaging beam from the sample 3 passes sequentially through the first beam splitter 6, the second beam splitter 801, and the lens 804 and is incident on the camera 805 to form an image, thereby generating a sample image. The stage 2 is controlled to move along the direction of the camera's incident optical axis to obtain sample images at different positions. Then, based on the sample image information at different positions, the position of the sample image with higher clarity is determined as the first focal plane. When the illumination module 10 emits an illumination beam, the third shutter 701 is closed, and the first shutter 503 and the second shutter 702 are opened. The illumination beam emitted by the illumination module 10 passes through the target area selection module 70 and is incident on the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the incident beam onto the sample 3. The reflected imaging beam from the sample 3 passes sequentially through the first beam splitter 6, the second beam splitter 801, and the lens 804 and is incident on the camera 805 to form an image, thereby generating a sample image. The stage 2 is controlled to move along the direction of the camera's incident optical axis to obtain sample images at different positions. Based on the sample image information at different positions, the position of the sample image with higher clarity is determined as the first focal plane. When the illumination module 10 emits an illumination beam, the third shutter 701 is closed, and the first shutter 503 and the second shutter 702 are opened. The illumination beam emitted by the illumination module 10 passes through the target area selection module 70 and is incident on the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the incident beam onto the sample 3. The reflected imaging beam from the target area selection The beam is reflected to sample 3, and the imaging beam reflected from sample 3 is incident on the first beam splitter 6. Simultaneously, the first beam splitter 6 also transmits the beam emitted from the target area selection module 70 to the reference mirror 501. The light spot on the reference mirror 501 is reflected and then passes through the first lens 502 and the first shutter 503 before entering the first beam splitter 6. The imaging beam reflected from sample 3 and the beam reflected from the reference mirror 501 interfere at the first beam splitter 6, producing an interference beam. This interference beam is reflected by the second beam splitter 801 and then passes through the second lens 802 into the light intensity collector 803. The light intensity collector 803 acquires the interference beam, processes it to obtain an interference signal, and controls the stage 2 to move along the direction of the camera's incident optical axis to acquire interference signals at different positions. Based on the interference signals at different positions, the sample image position corresponding to the preset interference signal is determined as the second focal plane. The preset interference signal can be obtained based on the acquired interference signal and actual needs, and is not specifically limited here. The difference between the first and second focal planes is the system focusing deviation.

[0082] It is understood that the above is only an example illustrating one way to obtain system focus deviation, and there may be other ways to obtain system focus deviation, which are not specifically limited here.

[0083] S103. During the detection phase, the optimal focal plane is determined based on the system focusing deviation and the interference signal obtained by the interference module.

[0084] Among them, the optimal focal plane represents the distance between the sample and the imaging module when the imaging module acquires a high-resolution sample image.

[0085] For details, please refer to Figure 1The system controls the third shutter 701 to close, and the first shutter 503 and second shutter 702 to open. The illumination beam emitted from the illumination module 10 passes through the second shutter 702, the fourth lens 703, the light-shielding component 74, and the fifth lens 705 and is incident on the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the beam emitted from the target area selection module 70 onto the sample 3, and the imaging beam reflected from the sample 3 is incident on the first beam splitter 6. Simultaneously, the first beam splitter 6 also transmits the beam emitted from the target area selection module 70 to the reference mirror 501. The light spot on the reference mirror 501 is reflected and then passes through the first lens 502 and the first shutter 503 before being incident on the first beam splitter 6. The sample 3 reflects... The imaging beam and the beam reflected by the reference mirror 501 interfere at the first beam splitter 6 to generate an interference beam. After being reflected by the second beam splitter 801, the interference beam passes through the second lens 802 and enters the light intensity collector 803. The light intensity collector 803 can acquire the interference beam and process it to obtain the interference signal. It controls the stage 2 to move along the direction of the incident optical axis of the camera to acquire interference signals at different positions. Then, based on the interference signals at different positions, the sample image position corresponding to the preset interference signal is determined as the sample height. Based on the acquired sample height and the system focusing deviation, the optimal focal plane of the current sample can be determined, thereby improving the determination rate and accuracy of the optimal focal plane.

[0086] It should be noted that the samples used in the training phase are training samples, while the samples used in the detection phase are target samples to be detected.

[0087] The technical solution of this invention adjusts the position of the stage and the target area selection module during the debugging phase when the illumination module emits an illumination beam. This ensures that the sample is located at the center of the field of view of the imaging module and that the center of the target area selection module coincides with the center of the field of view. Then, a training phase is initiated to obtain the system focusing deviation of the optical detection device. This allows the optimal focal plane to be determined during the detection phase after the target sample is placed on the stage, based on the system focusing deviation and the interference signal obtained by the interference module. Thus, when detecting multiple target samples of the same type, only one target sample needs to undergo the detection phase to obtain the optimal focal plane for that type of target sample, eliminating the need to perform the detection phase on all target samples and improving the rate of determining the optimal focal plane.

[0088] Example 3

[0089] Based on the above embodiments, this embodiment describes how, when the illumination module emits an illumination beam, the position of the stage and the position of the target area selection module are adjusted so that the sample is located at the center of the field of view of the imaging module and the light transmission center of the target area selection module coincides with the center of the field of view. Figure 6 This is a flowchart of a method for determining the optimal focal plane of an optical detection device according to Embodiment 3 of the present invention, as shown below. Figure 6 As shown, the method for determining the optimal focal plane of this optical detection device includes:

[0090] S201. During the debugging phase, control the optical detection device to perform the shooting process and adjust the position of the stage relative to the center of the field of view so that the sample is located at the center of the field of view of the imaging module.

[0091] The process of the sample reflecting the illumination beam from the illumination module back to the imaging module without passing through the target area selection module is called the imaging process.

[0092] For details, please refer to Figure 3 The principle of controlling the optical detection device to perform the shooting process is as follows: the first shutter 503 is closed, the illumination beam emitted from the illumination module 10 is incident on the incident surface of the first beam splitter 6, the first beam splitter 6 reflects the incident beam to the sample 3, and the imaging beam reflected by the sample 3 passes through the first beam splitter 6, the second beam splitter 801 and the lens 804 in sequence and is incident on the camera 805 to form an image, thereby generating a sample image. According to the position of the sample in the field of view in the sample image, the stage 2 is adjusted to move along the direction perpendicular to the incident optical axis of the camera so that the sample is located in the center of the field of view of the imaging module, so as to improve the signal strength and signal reliability of the subsequent acquired signal and improve the accuracy of the optimal focal plane.

[0093] For example, Figure 7 This is a schematic diagram of a sample structure provided in Embodiment 3 of the present invention. The sample has a stepped structure with surface A and surface B. Surface B includes an alignment mark B0. The reflectivity of surfaces A and B can be set to be different. When the optical detection device performs the imaging process and adjusts the position of the stage 2 relative to the center of the field of view so that the sample is located at the center of the field of view of the imaging module, the stage 2 can be controlled to move along the first direction X to drive the sample 3 to move in the first direction X, so that the alignment mark B0 appears at the center of the field of view of the imaging module 80. The sample image acquired by the imaging module 80 is processed to obtain the position coordinates of the alignment mark B0 in the field of view of the imaging module 80. Then, the position of the stage 2 is adjusted according to the position coordinates so that the alignment mark B0 is located at the center of the field of view of the imaging module 80.

[0094] S202. When the sample is located at the center of the field of view of the imaging module, control the optical detection device to perform the calibration process and adjust the position of the target area selection module in the optical detection device so that the light transmission center of the target area selection module coincides with the center of the field of view.

[0095] The calibration process involves the illumination beam emitted from the illumination module passing through the target area selection module and illuminating the sample surface, with the sample reflecting the illumination beam back to the imaging module.

[0096] For details, please refer to Figure 3 After sample 3 is located at the center of the field of view of imaging module 80, the first shutter 503 is still closed. The illumination beam emitted from illumination module 10 passes through target area selection module 70 and enters the incident surface of first beam splitter 6. First beam splitter 6 reflects the beam emitted from target area selection module 70 to sample 3. The imaging beam reflected by sample 3 passes through first beam splitter 6, second beam splitter 801 and lens 804 in sequence and enters camera 805 to generate sample image. At the same time, second beam splitter 801 also reflects the imaging beam reflected by sample 3 to light intensity collector 8. 03. The light intensity collector 803 can acquire the interference signal of the light beam, which includes the light beam intensity. The light transmittance at the light transmission center of the light-shielding component 704 is adjusted to 100%, while the light transmittance at other positions is 0% or less than 100%. The position of the light-shielding component 704 is then adjusted so that when the light intensity collector 803 acquires a strong light beam intensity signal, it is assumed that the light transmission center of the target area selection module 7 coincides with the field of view center of the imaging module. This eliminates the need to adjust the position of the target area selection module during the subsequent determination of the optimal focal plane, thereby improving the efficiency of obtaining the optimal focal plane.

[0097] For example, Figure 8 This is a curve showing the relationship between beam intensity and the position of the field stop provided in Embodiment 3 of the present invention, for reference. Figure 4 and Figure 8 When the optical detection device performs the calibration process and adjusts the position of the target area selection module within the optical detection device so that the light transmission center of the target area selection module coincides with the field of view center, the position and field of view of the field stop 708 can be adjusted. The light intensity collector 803 acquires the correspondence between the intensity of the light beam passing through the field stop 708 and the position of the field stop 708. Figure 8 As shown, the position and field of view of the field stop 708 are determined by the coordinates of point C and point D. The polygon formed by Cx, Cy, Dx and Dy is the field of view of the field stop 708, and the center of the polygon is the center of the field of view of the field stop 708.

[0098] S203. During the training phase, after the sample is located at the center of the field of view of the imaging module and the center of the target region selection module coincides with the center of the field of view, the system focusing deviation of the optical detection device is obtained.

[0099] S204. During the detection phase, the optimal focal plane is determined based on the system focusing deviation and the interference signal obtained by the interference module.

[0100] It should be noted that once the optimal focal plane is determined, each target sample can be placed at the optimal focal plane, and the optical detection device can be controlled to perform the imaging process on the target sample. The sample image acquired by the imaging module can be processed to achieve defect detection at relevant locations of the target sample.

[0101] The technical solution of this invention involves controlling the optical detection device to perform the shooting process and adjusting the position of the stage relative to the center of the field of view so that the sample is located at the center of the field of view of the imaging module. When the sample is located at the center of the field of view of the imaging module, the optical detection device is controlled to perform a calibration process, adjusting the position of the target area selection module in the optical detection device so that the light transmission center of the target area selection module coincides with the center of the field of view. In this way, in the subsequent process of determining the optimal focal plane, it is not necessary to adjust the position of the stage in the direction perpendicular to the incident optical axis of the camera and the position of the target area selection module, thereby improving the efficiency and accuracy of obtaining the optimal focal plane.

[0102] Example 4

[0103] Based on the above embodiments, this embodiment describes the situation of obtaining the system focusing deviation of the optical detection device. Figure 9 This is a flowchart of a method for determining the optimal focal plane of an optical detection device according to Embodiment 4 of the present invention, as shown below. Figure 9 As shown, the method for determining the optimal focal plane of this optical detection device includes:

[0104] S301. During the debugging phase, when controlling the illumination module to emit the illumination beam, adjust the position of the stage and the position of the target area selection module so that the sample is located at the center of the field of view of the imaging module and the light transmission center of the target area selection module coincides with the center of the field of view.

[0105] S302. During the training phase, after the sample is located at the center of the field of view of the imaging module and the center of the target area selection module coincides with the center of the field of view, the optical detection device is controlled to perform the shooting process, and the distance between the stage and the imaging module is adjusted so that the imaging module can acquire multiple sample images.

[0106] The process of the sample reflecting the illumination beam from the illumination module back to the imaging module without passing through the target area selection module is called the imaging process.

[0107] For details, please refer to Figure 4 When the illumination module emits an illumination beam, the first shutter 503 is closed. The illumination beam emitted by the illumination module 10 is incident on the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the incident beam onto the sample 3. The imaging beam reflected by the sample 3 passes through the first beam splitter 6, the second beam splitter 801, and the lens 804 in sequence and is incident on the camera 805 to generate a sample image. The distance between the stage 2 and the imaging module 80 is controlled so that the imaging module 80 can acquire multiple sample images at different positions, which is convenient for subsequent analysis of multiple sample images.

[0108] S303. Determine the first focal plane of the optical detection device based on each sample image.

[0109] Specifically, the imaging module can acquire images of each sample and the distance between the stage and the imaging module. The imaging module is equipped with an image processing unit, which can process each sample image and obtain parameters related to sharpness, such as the resolution of each sample image, so as to use the position of the sample image with higher resolution as the first focal plane.

[0110] S304. Control the optical detection device to perform the interference process and adjust the distance between the stage and the imaging module so that the interference module can acquire multiple interference signals.

[0111] The process of the illumination beam emitted from the illumination module illuminating the sample surface and the interference module, and the process of the sample reflecting the illumination beam and the interference reflection beam reflecting the illumination beam from the interference module being incident on the imaging module, is called the interference process.

[0112] For details, please refer to Figure 4 When the illumination module emits an illumination beam, the first shutter 503 is opened. The illumination beam emitted by the illumination module 10 passes through the target area selection module 70 and is incident on the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the beam emitted by the target area selection module 70 onto the sample 3. The imaging beam reflected by the sample 3 is incident on the first beam splitter 6. At the same time, the first beam splitter 6 also transmits the beam emitted by the target area selection module 70 to the reference mirror 501. The light spot on the reference mirror 501 is reflected and then passes sequentially through the first lens 502 and the second lens 503. A shutter 503 is incident on the first beam splitter 6. The imaging beam reflected by the sample 3 and the beam reflected by the reference mirror 501 interfere at the first beam splitter 6 to produce an interference beam. The interference beam is reflected by the second beam splitter 801 and enters the light intensity collector 803 through the second lens 802. The light intensity collector 803 can acquire the interference beam and process it to obtain the interference signal. The distance between the stage 2 and the imaging module 80 is controlled to obtain interference signals at different positions, which facilitates the subsequent analysis of multiple interference signals.

[0113] S305. Determine the second focal plane of the optical detection device based on each interference signal.

[0114] Specifically, the interference signal includes an interference fringe image, which reflects the correspondence between the sample position and the intensity of the sample interference beam. This allows the sample position corresponding to the preset interference signal to be determined as the second focal plane based on the interference fringe image. The preset interference signal can be determined according to actual needs. For example, the preset interference signal includes the maximum or minimum value of the acquired interference beam intensity, but it can also be other values, which are not specifically limited here.

[0115] S306. Determine the system focusing deviation based on the first focal plane and the second focal plane.

[0116] Specifically, the system focus deviation represents the height difference between the first focal plane corresponding to the clear sample image acquired by the imaging module and the second focal plane corresponding to the preset interference signal acquired by the interferometer module. The difference between the first and second focal planes is used as the system focus deviation to subsequently determine the optimal focal plane, thus improving the accuracy of the optimal focal plane. In practical sample detection applications, since the samples being detected have strong consistency—that is, the interference fringes produced by each sample are basically similar—it can be assumed that the system focus deviation of all samples is the same. Therefore, determining the system focus deviation using only one sample is sufficient to apply it to the detection of all samples, simplifying the detection process.

[0117] S307. During the detection phase, the optimal focal plane is determined based on the system focusing deviation and the interference signal obtained by the interference module.

[0118] In the technical solution of this invention embodiment, during the debugging phase, the optical detection device is controlled to perform the imaging process, and the distance between the stage and the imaging module is adjusted so that the imaging module acquires multiple sample images. Based on each sample image, the first focal plane of the optical detection device is determined. Then, the optical detection device is controlled to perform the interference process, and the distance between the stage and the imaging module is adjusted so that the interference module acquires multiple interference signals. Based on each interference signal, the second focal plane of the optical detection device is determined. Then, based on the first and second focal planes, the system focusing deviation is determined so that the optimal focal plane can be determined subsequently based on the system focusing deviation, thereby improving the accuracy of the optimal focal plane.

[0119] Example 5

[0120] Based on the above embodiments, this embodiment describes the interference signal obtained by the system focusing deviation and the interference module. Figure 10 This is a flowchart of a method for determining the optimal focal plane of an optical detection device according to Embodiment 5 of the present invention, as shown below. Figure 10 As shown, the method for determining the optimal focal plane of this optical detection device includes:

[0121] S401. During the debugging phase, when controlling the illumination module to emit the illumination beam, adjust the position of the stage and the position of the target area selection module so that the sample is located at the center of the field of view of the imaging module and the light transmission center of the target area selection module coincides with the center of the field of view.

[0122] S402. During the training phase, after the sample is located at the center of the field of view of the imaging module and the center of the target region selection module coincides with the center of the field of view, the system focusing deviation of the optical detection device is obtained.

[0123] S403. During the detection phase, the target sample is placed on the stage, the optical detection device is controlled to perform the interference process, and the distance between the stage and the imaging module is adjusted so that the interference module acquires multiple interference signals.

[0124] The process of the illumination beam emitted from the illumination module illuminating the sample surface and the interference module, and the process of the sample reflecting the illumination beam and the interference reflection beam reflecting the illumination beam from the interference module being incident on the imaging module, is called the interference process.

[0125] For details, please refer to Figure 4 The first shutter 503 is opened, and the illumination beam emitted from the illumination module 10 passes through the second shutter 702, the fourth lens 703, the light-shielding component 74, and the fifth lens 705 to the incident surface of the first beam splitter 6. The first beam splitter 6 reflects the beam emitted from the target area selection module 70 to the sample 3. The imaging beam reflected from the sample 3 is then incident on the first beam splitter 6. The first beam splitter 6 also transmits the beam emitted from the target area selection module 70 to the reference mirror 501. The light spot on the reference mirror 501 is reflected and then passes sequentially through the first lens 502. The first shutter 503 incident on the first beam splitter 6, the imaging beam reflected by the sample 3 and the beam reflected by the reference mirror 501 interfere at the first beam splitter 6 to produce an interference beam. The interference beam is reflected by the second beam splitter 801 and enters the light intensity collector 803 through the second lens 802. The light intensity collector 803 can acquire the interference beam and process it to obtain the interference signal. It controls the distance between the stage and the imaging module to obtain the interference signal of the sample at different positions, which is convenient for subsequent analysis of multiple interference signals.

[0126] S404. Determine the target sample height of the stage based on the interference signals.

[0127] Specifically, the interference signal includes an interference fringe image, which reflects the correspondence between the sample position and the intensity of the sample interference beam. This allows the target sample height to be determined based on the sample position corresponding to the preset interference signal, using the interference fringe image as the basis. The preset interference signal can be determined according to actual needs. For example, the preset interference signal includes the maximum or minimum value of the acquired interference beam intensity, but it can also be other values; no specific limitations are made here.

[0128] S405. Determine the optimal focal plane based on the target sample height and system focusing deviation.

[0129] Among them, the optimal focal plane represents the distance between the sample and the imaging module when the imaging module acquires a high-resolution sample image.

[0130] Specifically, if the height of the target sample obtained through the interference process is directly used as the optimal focal plane, the quality of the sample image acquired by the subsequent imaging module will be poor due to the existence of system focusing deviation. Therefore, it is necessary to consider the system focusing deviation and use the sum of the target sample height and the system focusing deviation as the optimal focal plane to improve the accuracy of the optimal focal plane.

[0131] The technical solution of this invention involves placing the target sample on a stage, controlling the optical detection device to perform an interference process, and adjusting the distance between the stage and the imaging module so that the interference module acquires multiple interference signals. Based on each interference signal, the height of the target sample on the stage is determined. Based on the height of the target sample and the system focusing deviation, the optimal focal plane is determined to improve the accuracy of the optimal focal plane and the reliability of subsequent sample detection.

[0132] Example 6

[0133] This invention also provides a computer-readable storage medium storing computer instructions. The computer instructions are used to cause a processor to execute the optimal focal plane determination method of the optical detection device provided in this invention, and have the corresponding functional modules and beneficial effects of the execution method, which will not be described in detail here.

[0134] Computer-readable storage media can be tangible media that may contain or store computer programs for use by or in conjunction with an instruction execution system, apparatus, or device. Computer-readable storage media can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, computer-readable storage media can be machine-readable signal media. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0135] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for determining the optimal focal plane of an optical detection device, characterized in that, The optical detection device includes at least: an illumination module, a stage, an interference module, a target area selection module, and an imaging module. The illumination module is used to emit an illumination beam, the stage is used to place a sample, the interference module is used to acquire interference signals of the sample image, the target area selection module is used to adjust the sample image acquired by the imaging module or the interference module, and the imaging module is used to acquire the sample image. The method for determining the optimal focal plane of the optical detection device includes a debugging phase, a training phase, and a detection phase. During the debugging phase, when controlling the illumination module to emit an illumination beam, the position of the stage and the position of the target area selection module are adjusted so that the sample is located at the center of the field of view of the imaging module and the center of the target area selection module coincides with the center of the field of view. During the training phase, after the sample is located at the center of the field of view of the imaging module and the center of the target region selection module coincides with the center of the field of view, the system focusing deviation of the optical detection device is obtained; the system focusing deviation represents the height difference between the first focal plane corresponding to the clear sample image obtained by the imaging module and the second focal plane corresponding to the preset interference signal obtained by the interference module. During the detection phase, the optimal focal plane is determined based on the system focusing deviation and the interference signal acquired by the interference module.

2. The method for determining the optimal focal plane of the optical detection device according to claim 1, characterized in that, When the illumination module emits an illumination beam, the position of the stage and the position of the target region selection module are adjusted so that the sample is located at the center of the field of view of the imaging module and the light transmission center of the target region selection module coincides with the center of the field of view, including: The optical detection device is controlled to perform the imaging process, and the position of the stage relative to the center of the field of view is adjusted so that the sample is located at the center of the field of view of the imaging module. When the sample is located at the center of the field of view of the imaging module, the optical detection device is controlled to perform a calibration process to adjust the position of the target area selection module in the optical detection device so that the light transmission center of the target area selection module coincides with the center of the field of view. The process of the sample reflecting the illumination beam to the imaging module when the illumination beam emitted by the illumination module does not pass through the target area selection module and illuminates the sample surface is the imaging process; the process of the sample reflecting the illumination beam to the imaging module when the illumination beam emitted by the illumination module passes through the target area selection module and illuminates the sample surface is the calibration process.

3. The method for determining the optimal focal plane of the optical detection device according to claim 1, characterized in that, The system focusing deviation of the optical detection device is obtained, including: The optical detection device is controlled to perform the imaging process, and the distance between the stage and the imaging module is adjusted so that the imaging module acquires multiple sample images; Based on each of the sample images, the first focal plane of the optical detection device is determined; The optical detection device is controlled to perform an interference process, and the distance between the stage and the imaging module is adjusted so that the interference module acquires multiple interference signals; The second focal plane of the optical detection device is determined based on each of the interference signals. The system focusing deviation is determined based on the first focal plane and the second focal plane; The process of the sample reflecting the illumination beam to the imaging module when the illumination beam emitted from the illumination module does not pass through the target area selection module and illuminates the sample surface is the imaging process; the process of the sample reflecting the illumination beam and the interference reflection beam from the interference module being incident on the imaging module is the interference process.

4. The method for determining the optimal focal plane of the optical detection device according to claim 3, characterized in that, Determining the system focusing deviation based on the first focal plane and the second focal plane includes: The difference between the first focal plane and the second focal plane is taken as the focusing deviation of the system.

5. The method for determining the optimal focal plane of the optical detection device according to claim 1, characterized in that, Determining the optimal focal plane based on the system focusing deviation and the interference signal acquired by the interference module includes: The target detection sample is placed on the stage, the optical detection device is controlled to perform the interference process, and the distance between the stage and the imaging module is adjusted so that the interference module acquires multiple interference signals. The target sample height of the stage is determined based on the interference signals described above. The optimal focal plane is determined based on the target sample height and the system focusing deviation. The process in which the illumination beam emitted by the illumination module illuminates the sample surface and the interference module after passing through the target area selection module, and the sample reflection beam after the sample reflects the illumination beam and the interference reflection beam after the interference module reflects the illumination beam are incident on the imaging module, is called the interference process.

6. The method for determining the optimal focal plane of the optical detection device according to claim 5, characterized in that, Determining the optimal focal plane based on the target sample height and the system focusing deviation includes: The sum of the target sample height and the system focusing deviation is taken as the optimal focal plane.

7. An optical detection device, characterized in that, At least including: Illumination module, stage, interference module, target area selection module, imaging module, and controller; The lighting module includes at least a lighting source, and the lighting module is used to emit a lighting beam; The stage is used to place the sample; The imaging module includes an objective lens, a first beam splitter, a second beam splitter, a third lens, and a camera. The imaging module is used to acquire sample images. The interference module includes a first shutter, a first lens, a reference mirror, a second lens, and a light intensity collector. The first lens is located in the optical path between the first shutter and the reference mirror, and the second lens is located in the optical path between the second beam splitter and the light intensity collector. The interference module is used to acquire interference signals. The target region selection module includes at least a light-shielding component, and the target region selection module is used to adjust the sample image acquired by the imaging module or the interference module; The controller is electrically connected to the camera, the target area selection module, and the interference module, respectively, and is used to execute the optimal focal plane determination method of the optical detection device according to any one of claims 1-6.

8. The optical detection device according to claim 7, characterized in that, When the target area selection module is located on the optical path between the illumination module and the first beam splitter, the target area selection module further includes a fourth lens and a fifth lens; The fourth lens is located in the optical path between the illumination module and the light-shielding component, and the fifth lens is located in the optical path between the light-shielding component and the first beam splitter.

9. The optical detection device according to claim 7, characterized in that, When the target area selection module is located in the optical path between the second lens and the light intensity collector, the light-shielding component includes a light-shielding plate or a field aperture. The light-shielding sheet includes multiple light-shielding areas, and the light transmittance of each light-shielding area is adjustable.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the method for determining the optimal focal plane of the optical detection apparatus according to any one of claims 1-6.

Images