Confocal imaging system and method based on surface scanning

Abstract

The invention provides a confocal imaging system and method based on surface scanning, and belongs to the technical field of confocal spectral imaging. Comprising a laser, a first laser beam expander, a second laser beam expander, a cylindrical lens, a dichroscope, an array optical fiber bundle, an imaging lens, a reflector, a microscope objective, a to-be-detected sample glass slide, an optical fiber collimating lens, a diffraction grating, an imaging concave reflector and an area array CCD detector. The left side of the array optical fiber bundle is connected with an area array arrangement end, and the right side of the array optical fiber bundle is provided with a linear array arrangement end; the collected Raman spectrum signal has high chemical specificity, different chemical substances can be distinguished, information such as contents of different molecules can be obtained, multi-parameter analysis can be carried out, a sample does not need to be pretreated, the structure and the property of the sample cannot be damaged, in-situ analysis can be carried out on the sample, and the detection accuracy is high. The method has the characteristics of non-destructiveness, high chemical specificity, high spatial resolution, multi-parameter analysis and the like, and is suitable for popularization.

Description

Technical Field

[0001] The invention belongs to the technical field of confocal spectral imaging, in particular to a confocal imaging system and method based on surface scanning. Background Art

[0002] When collecting spectral data of target samples, the confocal system can eliminate the interference of stray signals from non-focus points, and has higher imaging resolution and lower data noise. It is an important means of modern biological research; especially in the analysis and detection of living cells and biological activity, the rapid realization of three-dimensional imaging is of great significance.

[0003] Specifically, confocal imaging technology is an advanced optical imaging technology based on the principles of laser scanning and conjugate focusing to achieve high-resolution, three-dimensional imaging of samples. Its core lies in the precise focusing of the optical path (excitation and emission) at two positions. When the confocal scanner is operating, the excitation light is focused on the surface of the sample point through specific optical components, causing the substances in the sample to be stimulated to produce fluorescence emission or Raman scattering; while the emission light is focused at the pinhole. The pinhole acts as a spatial filter, allowing only spectral signals from the focal plane to pass through, blocking stray light from non-focal planes, ensuring that the collected light signal is highly pure, effectively reducing background noise interference, and laying the foundation for subsequent high-definition imaging.

[0004] Compared with traditional microscopes, confocal spectral imaging technology has significant advantages, for example: ① Traditional microscope imaging relies on the transmission or reflection of light, and its resolution is constrained by the optical diffraction limit. When observing thick samples or pursuing high-resolution imaging, the image is often blurred due to the scattering and absorption of light, and it is difficult to distinguish signals inside and outside the focal plane, and the background noise is large. Confocal imaging technology breaks through the traditional diffraction limit with the help of the high coherence, high intensity and precise focusing characteristics of lasers. It can not only perform fine optical sectioning of thick fluorescent specimens (up to 50 µm and above), and the thickness of the section is precisely controlled at about 0.5 to 1.5 µm, but also obtain a series of optical sectioning images by precisely moving the specimen along the microscope Z-axis, thereby realizing the reconstruction of the three-dimensional morphology of the sample, providing researchers with precise insights into the microscopic world in the fields of biomedicine and materials science.

[0005] ② From the perspective of resolution, traditional optical microscopes are restricted by the optical diffraction limit, and their lateral resolution is usually in the range of 200-500 nanometers. The axial resolution is even more limited, which makes it difficult to meet the needs of precise observation of microscopic details such as fine structures within cells and fine morphology of nanomaterials. Confocal microscopes rely on the advantages of confocal technology and laser light sources. Some advanced systems can even have a lateral resolution of tens of nanometers, and the axial resolution is also significantly improved. They can clearly distinguish tiny structural differences of samples in three-dimensional space. For example, in cell biology research, they can accurately present the morphology, distribution and interaction relationships of organelles.

[0006] ③ In terms of imaging depth, when traditional microscopes image thick samples, they cannot eliminate the interference of non-focal plane information. As the thickness of the sample increases, the image becomes increasingly blurred and the effective imaging depth is shallow. Confocal microscopes can adjust parameters such as the distance between the objective lens and the sample and the size of the pinhole to scan and image samples within a certain thickness range layer by layer, obtain clear optical sections at different depths, and have an imaging depth of up to hundreds of microns, demonstrating powerful depth detection capabilities in application scenarios such as biological tissue slicing and multi-layer material structure analysis.

[0007] ④ In terms of background noise control, when traditional microscopes are used for imaging, a large amount of background noise such as stray light and scattered light from the non-focal plane of the sample, the surrounding environment, and the optical components themselves is mixed into the imaging light path, seriously reducing the image contrast and clarity; the confocal microscope uses the spatial filtering characteristics of the pinhole to block the non-focal plane noise signal from the source, significantly purifies the imaging background, and greatly improves the image contrast, providing excellent imaging conditions for weak light signal detection and fine structure resolution, which effectively promotes the development of cutting-edge scientific research and high-precision industrial detection.

[0008] However, existing confocal imaging technologies are mainly based on point scanning, which collects characteristic signals of the target area in a point-by-point scanning manner and restores them into an image with intensity as pixel value; Traditional point scanning confocal imaging technology has problems such as long time consumption, low efficiency and phototoxicity when detecting optical signals on material surfaces and biological tissue sections, which limits its widespread promotion in practical applications.

[0009] There is also a spinning disk confocal microscope in the prior art, which innovatively adopts a spinning disk structure to replace the traditional single pinhole design. There are many pinholes evenly distributed on the spinning disk, and with the high-speed rotation mechanism, high-speed parallel scanning imaging of the sample can be achieved; at the moment when the excitation light irradiates the sample, multiple pinholes synchronously collect signals from different positions, which improves the imaging speed. Dozens or even hundreds of frames of images can be acquired per second, effectively capturing the dynamic processes of living cells, such as cell migration, mitosis and other instantaneous changes, and providing a powerful tool for real-time monitoring research in cell dynamics, developmental biology, etc.; at the same time, its imaging resolution and contrast can still maintain a high level under high-speed imaging, and it performs well in applications such as observation of rapid physiological processes and dynamic behaviors of microorganisms, broadening the boundaries of confocal imaging technology in the field of dynamic life phenomenon research.

[0010] However, the spinning disk confocal system is only suitable for applications in the field of fluorescence intensity measurement and cannot provide more detailed information such as the chemical composition of the sample. Summary of the invention

[0011] In order to solve the above technical problems, the present invention provides a confocal imaging system and method based on surface scanning. In view of the slow scanning speed of traditional single-point confocal spectral imaging technology, a confocal spectral imaging system with surface array rapid imaging is developed, which improves the efficiency of three-dimensional confocal spectral imaging by 2 orders of magnitude. It can also simultaneously obtain the Raman spectrum and spatial information of the sample, perform multi-parameter analysis, and provide sample information far exceeding that provided by the turntable confocal imaging technology in the prior art.

[0012] A confocal imaging system and method based on surface scanning, wherein: A confocal imaging system based on surface scanning, comprising: a laser, a first laser beam expander, a second laser beam expander, a cylindrical lens, a dichroic mirror, an array fiber bundle, an imaging lens, a reflector, a microscope objective, a sample slide to be tested, a fiber collimator, a diffraction grating, an imaging concave reflector, and a surface array CCD detector; the left side of the array fiber bundle is connected to a surface array arrangement end, and the right side of the array fiber bundle is provided with a linear array arrangement end; The laser is used to emit a laser beam; The first laser beam expander and the second laser beam expander serve as a beam expander combination and are used together to expand the laser beam; The cylindrical lens is used to: focus the expanded laser beam into a linear spot; The dichroic mirror is used to: reflect the line light spot, focus it to the line array arrangement end, and transmit it to the planar array arrangement end through the array optical fiber bundle; form a planar array of laser light emitting points at the planar array arrangement end; each of the laser light emitting points can be regarded as a laser excitation point of laser confocal; The imaging lens is used to collimate the laser light emitting point into a series of parallel lights, which are then reflected by the reflector to the microscope objective lens for focusing, and then project a laser excitation point array pattern with the same arrangement as the laser light emitting point on the surface of the sample slide to be tested; The Raman scattered light generated by the sample returns according to the reversibility principle of light, and passes through the microscope objective, reflector, imaging lens, planar array end, array fiber bundle, and linear array end in sequence. At this time, the scattered signal emitted passes through the dichroic mirror and directly transmits into the Raman spectrometer. At this time, the excitation light and Rayleigh scattered light are isolated by the dichroic mirror. The Raman scattered light is collimated by a fiber collimator and incident on the diffraction grating, where it splits the light and transmits the diffracted light to the imaging concave reflector, where it is focused on the area array CCD detector.

[0013] As an example, the cylindrical lens adopts: Powell prism.

[0014] As an example, the first laser beam expander and the second laser beam expander are used as a beam expander combination to expand the laser beam to between 8 and 10 mm.

[0015] As an example, the first laser beam expander and the second laser beam expander are used as a beam expander combination to expand the laser beam to more than 10 mm.

[0016] As an example, the number of the laser light emitting points is 2 or more.

[0017] As an example, the sample to be tested is placed on the sample slide.

[0018] As an example, the imaging concave reflector adopts: an off-axis aspheric focusing reflector.

[0019] A method of a confocal imaging system based on surface scanning, comprising: Step 1: The laser emits a laser beam, and after being expanded by the first laser beam expander and the second laser beam expander, the expanded laser beam is focused into a linear spot by a cylindrical lens; Step 2: Reflect the line light spot through a dichroic mirror, focus it to the linear array arrangement end, and then transmit it to the planar array arrangement end through an array optical fiber bundle to form a planar array of laser light spots; Step 3: The laser light emitting point enters the imaging lens, is collimated into a series of parallel lights, and then is reflected by the reflector to the microscope objective lens for focusing, and is projected onto the surface of the sample slide to be tested; at this time, the array pattern formed by the projected laser excitation points is the same as the arrangement of the laser light emitting points; Step 4: When the laser excitation point irradiates the surface of the sample slide to be tested, the irradiated sample generates Raman scattered light at the corresponding position; according to the reversibility principle of light, the Raman scattered light is collected by the microscope objective lens, reflected by the reflector and reaches the imaging lens. After being focused by the imaging lens, the Raman scattered light generated by each point on the sample is projected one by one onto the array end; As an example, each optical fiber at the end of the array collects the Raman signal of a point corresponding to the sample surface space; the end face of each optical fiber can be regarded as a confocal pinhole to isolate the Raman signals of points around the sample, which greatly improves the signal purity and quality of each point.

[0020] Step 5: The Raman scattered light is then transmitted to the other side of the linear array through the array fiber bundle, and then the Raman scattered light passes through the dichroic mirror and directly transmits into the fiber collimator. The excitation light and Rayleigh scattered light are isolated by the dichroic mirror. Step 6: The Raman scattered light is collimated by the fiber collimator and incident on the diffraction grating to complete the splitting, and the diffracted light is transmitted to the imaging concave reflector and finally focused on the area array CCD detector.

[0021] As an example, the array fiber bundle, the planar array arrangement end, and the linear array arrangement end all contain multiple optical fibers, and the number, specifications, and models of the optical fibers in the array fiber bundle, the planar array arrangement end, and the linear array arrangement end are the same.

[0022] As an example, the area array CCD detector includes: an area scanning Raman spectrometer, an aberration-eliminated spectrometer as a spectrum acquisition device, and a large area array CCD as a spectrum detector.

[0023] As an example, the Raman scattered light emitted from the linear array arrangement end is presented on the area array CCD detector after the combined action of the fiber optic collimator, the diffraction grating and the imaging concave reflector. At this time, the Raman scattered light is arranged longitudinally on the CCD target surface in sequence according to the fiber optic arrangement at the linear array arrangement end.

[0024] As an example, after the Raman signal of each individual optical fiber is split by the diffraction grating, it is spread out on the pixel row where the end face of the optical fiber is located. According to the number of pixels occupied by each individual optical fiber, several rows of pixels can be combined to form the Raman spectrum of an optical fiber.

[0025] As an example, the data collected by the entire CCD target surface are the Raman signals of all optical fibers. After data extraction, the Raman spectrum of each optical fiber can be restored, and thus the Raman spectrum of the point on the sample corresponding to each optical fiber can be restored to achieve Raman spectral imaging.

[0026] As an example, the area array CCD detector is connected to the host computer electrical signal, and after processing and reorganization by the host computer, a microscopic image composed of multiple pixels is reconstructed, and behind each pixel is a Raman spectrum; after analysis by the host computer, a complete Raman spectrum imaging map can be generated according to the type and abundance of chemical substances.

[0027] Beneficial effects of the present invention: The Raman spectral signal collected by the present invention can not only provide the molecular structure and chemical bond information of the substance, but also has high chemical specificity, and can distinguish different chemical substances. By analyzing the intensity of the spectral line, information such as the content of different molecules can also be obtained.

[0028] The Raman spectral imaging of the present invention can also simultaneously obtain the Raman spectrum and spatial information of the sample, and can perform multi-parameter analysis, such as chemical composition, molecular orientation, crystal structure, etc., and can provide sample information far exceeding that of ordinary spinning disk confocal imaging.

[0029] The Raman spectroscopy imaging of the present invention does not require pretreatment of the sample, will not destroy the structure and properties of the sample, and can perform in-situ analysis on the sample. As a powerful analysis structure and method, it has the characteristics of non-destructiveness, high chemical specificity, high spatial resolution and multi-parameter analysis, and has broad application prospects in the fields of biomedicine, materials science, environmental science, food safety, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The overall structural design diagram of a confocal imaging system based on surface scanning of the present invention. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments; based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0032] A confocal imaging system and method based on surface scanning, wherein: refer to Figure 1 As shown: a confocal imaging system based on surface scanning, comprising: a laser 1, a first laser beam expander 2, a second laser beam expander 3, a cylindrical lens 4, a dichroic mirror 5, an array fiber bundle 6, an imaging lens 7, a reflector 8, a microscope objective 9, a sample slide 10 to be tested, a fiber collimator 11, a diffraction grating 12, an imaging concave reflector 13 and a planar array CCD detector 14; The left side of the array optical fiber bundle 6 is connected to a planar array arrangement end 601, and the right side of the array optical fiber bundle 6 is provided with a linear array arrangement end 602; The laser 1 is used to emit a laser beam; The first laser beam expander 2 and the second laser beam expander 3 are used as a beam expander combination to expand the laser beam; The cylindrical lens 4 is used to focus the expanded laser beam into a linear spot; The dichroic mirror 5 is used to: reflect the line light spot, focus it to the line array arrangement end 602, and transmit it to the planar array arrangement end 601 through the array optical fiber bundle 6; form a planar array of laser light emitting points at the planar array arrangement end 601; each of the laser light emitting points can be regarded as a laser excitation point of laser confocal; The imaging lens 7 is used to collimate the laser light emitting point into a series of parallel lights, and then reflect the light through the reflector 8 to the microscope objective lens 9 for focusing, and then project an array pattern of laser excitation points arranged in the same manner as the laser light emitting point on the surface of the sample slide 10 to be tested; The Raman scattered light generated by the sample returns according to the reversibility principle of light, and passes through the microscope objective 9, the reflector 8, the imaging lens 7, the planar array end 601, the array fiber bundle 6, and the linear array end 602 in sequence. At this time, the scattered signal emitted passes through the dichroic mirror 5 and directly transmits into the fiber collimator. At this time, the excitation light and the Rayleigh scattered light are isolated by the dichroic mirror 5. As an example, in Raman spectroscopy, excitation light refers to: the laser used to excite Raman scattering of the sample, in order to distinguish it from Rayleigh scattered light; in the collected optical signal, there is not only the reflected excitation light, but also Rayleigh scattered light with exactly the same wavelength as the excitation light. These are not the optical signals we want and need to be filtered out using filters.

[0033] The Raman scattered light is collimated by the fiber collimator 11 and incident on the diffraction grating 12 , where it is split and transmitted to the imaging concave reflector 13 , where it is focused on the area array CCD detector 14 .

[0034] As an example, the cylindrical lens 4 adopts: Powell prism.

[0035] As an example, the first laser beam expander 2 and the second laser beam expander 3 are used as a beam expander combination to expand the laser beam to between 8 and 10 mm.

[0036] As an example, the first laser beam expander 2 and the second laser beam expander 3 are used as a beam expander combination to expand the laser beam to more than 10 mm.

[0037] As an example, the number of the laser light emitting points is 2 or more.

[0038] As an example, a sample 15 to be tested is placed on the sample slide 10 to be tested.

[0039] As an example, the imaging concave reflector 13 is an off-axis aspheric focusing reflector.

[0040] A method of a confocal imaging system based on surface scanning, comprising: Step 1: The laser 1 emits a laser beam, and after being expanded by the first laser beam expander 2 and the second laser beam expander 3, the expanded laser beam is focused into a linear spot by the cylindrical lens 4; Step 2: The line light spot is reflected by the dichroic mirror 5, focused to the linear array arrangement end 602, and then transmitted to the planar array arrangement end 601 through the array optical fiber bundle 6 to form a planar array of laser light spots; Step 3: The laser light emitting point enters the imaging lens 7, is collimated into a series of parallel lights, and then is reflected by the reflector 8 to the microscope objective lens 9 for focusing, and is projected onto the surface of the sample slide 10 to be tested; at this time, the array pattern formed by the projected laser excitation points is the same as the arrangement of the laser light emitting points; Step 4: When the laser excitation point irradiates the surface of the sample slide 10 to be tested, the irradiated sample 15 generates Raman scattered light at the corresponding position; according to the reversibility principle of light, the Raman scattered light is collected by the microscope objective 9, reflected by the reflector 8 and reaches the imaging lens 7. After being focused by the imaging lens, the Raman scattered light generated by each point on the sample is projected one by one onto the array end 601; As an example, each optical fiber at the array end 601 collects the Raman signal of a point corresponding to the sample surface space; the end face of each optical fiber can be regarded as a confocal pinhole to isolate the Raman signals of points around the sample, which greatly improves the signal purity and signal quality of each point.

[0041] Step 5: The Raman scattered light is then transmitted to the other side of the linear array end 602 through the array fiber bundle 6, and then the Raman scattered light passes through the dichroic mirror 5 and directly transmits into the fiber collimator 11, and the excitation light and the Rayleigh scattered light are isolated by the dichroic mirror 5; Step 6: The Raman scattered light is collimated by the fiber collimator 11 and incident on the diffraction grating 12 to complete the light splitting, and the diffracted light is transmitted to the imaging concave reflector 13 and finally focused on the area array CCD detector 14.

[0042] As an example, the array fiber bundle 6, the planar array end 601 and the linear array end 602 all include multiple optical fibers, and the number, specifications and models of the optical fibers in the array fiber bundle 6, the planar array end 601 and the linear array end 602 are the same.

[0043] As an example, the area array CCD detector 14 includes: an area scanning Raman spectrometer, an aberration-eliminated spectrometer as a spectrum acquisition device, and a large area array CCD as a spectrum detector.

[0044] As an example, the Raman scattered light emitted by the linear array arrangement end 602 is presented on the area array CCD detector 14 after the combined action of the fiber optic collimator 11, the diffraction grating 12 and the imaging concave reflector 13. At this time, the Raman scattered light is arranged longitudinally on the CCD target surface in sequence according to the fiber optic arrangement of the linear array arrangement end 602.

[0045] As an example, after the Raman signal of each individual optical fiber is split by the diffraction grating, it is spread out on the pixel row where the end face of the optical fiber is located. According to the number of pixels occupied by each individual optical fiber, several rows of pixels can be combined to form the Raman spectrum of an optical fiber.

[0046] As an example, the data collected by the entire CCD target surface are the Raman signals of all optical fibers. After data extraction, the Raman spectrum of each optical fiber can be restored, and thus the Raman spectrum of the point on the sample corresponding to each optical fiber can be restored to achieve Raman spectral imaging.

[0047] As an example, the excitation wavelength of the laser includes: 532 nm, 633 nm or 785 nm.

[0048] In order to better illustrate the design principle of the present invention, specific examples are given for comparison and explanation, which are described in detail as follows: First, when performing spectral imaging on a plane, the traditional single-point pinhole coupled confocal system needs to scan the entire plane point by point, which results in low scanning efficiency. To solve this problem, the present invention proposes to use a plane and array optical fiber bundle as a pinhole array for signal collection to complete the spectral signal collection of points in the entire field of view at one time.

[0049] Secondly, although the spinning disk confocal can also achieve fast planar signal acquisition, it can only collect light signal intensity information on the sample plane and cannot distinguish chemical substances on the sample plane; The present invention is different from the spinning disk confocal in that the surface and array confocal imaging systems collect spectral signals of the target area, which can not only analyze the abundance of the sample surface material through the spectral intensity, but also obtain information on the chemical composition of the sample surface through the analysis of the spectral line; Then, the line spot fiber coupling scheme adopted in the present invention can make the laser power passing through each optical fiber tend to be the same, so that the intensity of each pixel point in the imaging field of the entire spectral imaging remains equal, avoiding the problem of uneven field brightness caused by the uniformity of illumination intensity in microscopic imaging, thereby correctly feeding back the distribution information of different chemical compositions of the sample in space.

[0050] Again, the Raman lasers used in the present invention include but are not limited to 532 nm, 633 nm, and 785 nm. The specific excitation wavelength used depends on the sample. Ordinary material samples can use the 532 nm excitation line, which can bring higher overall signal intensity and higher collection efficiency. For some biological samples and samples with strong fluorescence emission, the 785 nm excitation line can be used, which can effectively avoid the interference of the sample's fluorescence emission on the sample's Raman spectrum.

[0051] Finally, the planar array-to-linear array optical fiber involved in the present invention is arranged in a line at the spectral analysis end, which is both a spatial filter for the excitation light and a spatial modulator for Raman scattering. It is arranged in a planar array at the confocal end, and each optical fiber end face is a confocal pinhole, forming a pinhole array with a hexagonal close-packed morphology. At the same time, it is both a confocal excitation pinhole and a confocal collection pinhole, so that the entire system presents a fully matched confocal performance.

[0052] The above are only preferred embodiments of the present invention. It should be understood that the description of the above embodiments is only used to help understand the method and core ideas of the present invention, and is not used to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, etc. made within the ideas and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A confocal imaging system based on surface scanning, characterized in that: include: A laser, a first laser beam expander, a second laser beam expander, a cylindrical lens, a dichroic mirror, an array fiber bundle, an imaging lens, a reflector, a microscope objective, a sample slide to be tested, a fiber collimator, a diffraction grating, an imaging concave reflector, and a surface array CCD detector; the left side of the array fiber bundle is connected to a surface array arrangement end, and the right side of the array fiber bundle is provided with a linear array arrangement end; The laser is used to emit a laser beam; The first laser beam expander and the second laser beam expander serve as a beam expander combination and are used together to expand the laser beam; The cylindrical lens is used to: focus the expanded laser beam into a linear spot; The dichroic mirror is used to: reflect the line light spot, focus it to the line array arrangement end, and transmit it to the planar array arrangement end through the array optical fiber bundle; form a planar array of laser light emitting points at the planar array arrangement end; each of the laser light emitting points can be regarded as a laser excitation point of laser confocal; The imaging lens is used to collimate the laser light emitting point into a series of parallel lights, which are then reflected by the reflector to the microscope objective lens for focusing, and then project a laser excitation point array pattern with the same arrangement as the laser light emitting point on the surface of the sample slide to be tested; The Raman scattered light generated by the sample returns according to the reversibility principle of light, and passes through the microscope objective, reflector, imaging lens, planar array end, array fiber bundle, and linear array end in sequence. At this time, the scattered signal emitted passes through the dichroic mirror and directly transmits into the fiber collimator. At this time, the excitation light and Rayleigh scattered light are isolated by the dichroic mirror. The Raman scattered light is collimated by a fiber collimator and incident on the diffraction grating, where it splits the light and transmits the diffracted light to the imaging concave reflector, where it is focused on the area array CCD detector.

2. A confocal imaging system based on surface scanning according to claim 1, characterized in that: The cylindrical lens adopts: Powell prism.

3. A confocal imaging system based on surface scanning according to claim 1, characterized in that: The first laser beam expander and the second laser beam expander serve as a beam expander combination to expand the laser beam to between 8 and 10 mm.

4. The confocal imaging system based on surface scanning according to claim 1, characterized in that: The first laser beam expander and the second laser beam expander serve as a beam expander combination to expand the laser beam to more than 10 mm.

5. The confocal imaging system based on surface scanning according to claim 1, characterized in that: The imaging concave reflector adopts: an off-axis aspheric focusing reflector.

6. A method of a confocal imaging system based on surface scanning, characterized in that: include: Step 1: The laser emits a laser beam, and after being expanded by the first laser beam expander and the second laser beam expander, the expanded laser beam is focused into a linear spot by a cylindrical lens; Step 2: Reflect the line light spot through a dichroic mirror, focus it to the linear array arrangement end, and then transmit it to the planar array arrangement end through an array optical fiber bundle to form a planar array of laser light spots; Step 3: The laser light emitting point enters the imaging lens, is collimated into a series of parallel lights, and then is reflected by the reflector to the microscope objective lens for focusing, and is projected onto the surface of the sample slide to be tested; at this time, the array pattern formed by the projected laser excitation points is the same as the arrangement of the laser light emitting points; Step 4: When the laser excitation point irradiates the surface of the sample slide to be tested, the irradiated sample generates Raman scattered light at the corresponding position; according to the reversibility principle of light, the Raman scattered light is collected by the microscope objective lens, reflected by the reflector and reaches the imaging lens. After being focused by the imaging lens, the Raman scattered light generated by each point on the sample is projected one by one onto the array end; Step 5: The Raman scattered light is then transmitted to the other side of the linear array through the array fiber bundle, and then the Raman scattered light passes through the dichroic mirror and directly transmits into the fiber collimator. The excitation light and Rayleigh scattered light are isolated by the dichroic mirror. Step 6: The Raman scattered light is collimated by the fiber collimator and incident on the diffraction grating to complete the splitting, and the diffracted light is transmitted to the imaging concave reflector and finally focused on the area array CCD detector.

7. The method of a confocal imaging system based on surface scanning according to claim 6, characterized in that: Each optical fiber at the end of the array arrangement collects the Raman signal of a point corresponding to the sample surface space; the end face of each optical fiber can be regarded as a confocal pinhole to block the Raman signals of points around the sample.

8. The method of a confocal imaging system based on surface scanning according to claim 6, characterized in that: The array fiber bundle, the planar array arrangement end and the linear array arrangement end all contain multiple optical fibers, and the number, specification and model of the optical fibers in the array fiber bundle, the planar array arrangement end and the linear array arrangement end are the same.

9. The method of a confocal imaging system based on surface scanning according to claim 6, characterized in that: The area array CCD detector comprises: an area scanning Raman spectrometer, a spectrometer with aberration elimination is used as a spectrum collection device, and a large area array CCD is used as a spectrum detector.

10. The method of the confocal imaging system based on surface scanning according to claim 6, characterized in that The Raman scattered light emitted from the linear array arrangement end is presented on the area array CCD detector after the combined action of the fiber collimator, diffraction grating and imaging concave reflector. At this time, the Raman scattered light is arranged longitudinally on the CCD target surface in sequence according to the fiber arrangement mode of the linear array arrangement end.

Images