Microscopic imaging system for dual-band LED illumination and use method

Abstract

The invention discloses a microscopic imaging system for dual-band LED illumination and a use method thereof.The microscopic imaging system comprises a dual-band illumination module, a double telecentric objective lens, a high-power imaging system and a low-power imaging system.The dual-band illumination module adopts a red light and blue light dual-band LED light source and combines the Kohler illumination technology to achieve the high-uniformity illumination effect; the high-magnification imaging system and the low-magnification imaging system both adopt double telecentric optical design, telecentric degrees of an object space and an image space are ensured to be smaller than or equal to 0.2 degree, meanwhile, the characteristic of large depth of field is obtained through collaborative design of optical parameters, a high-precision automatic focusing module is integrated, imaging definition is judged through an image definition evaluation algorithm, a high-magnification telecentric imaging lens group and a low-magnification telecentric imaging lens group are automatically adjusted, and rapid focusing is achieved. The problems that a traditional microscopic system is large in magnification error, insufficient in depth of field, low in focusing efficiency and poor in illumination stability are solved, and high-magnification and low-magnification simultaneous imaging is achieved.

Description

Technical Field

[0001] This invention relates to the field of microscopic imaging technology, specifically to a dual-band LED illumination microscopic imaging system and its usage method, which is suitable for scenarios such as precision measurement of semiconductor micro-sizes and full-domain detection of industrial micro-defects (such as identification of micro-cracks on the surface of aero-engine blades and detection of solder joint defects in electronic components). Background Technology

[0002] Microscopic imaging technology, as a core method of microscopic observation, is increasingly widely used in fields such as precision manufacturing and aerospace. However, with the upgrading of technological demands, traditional microscopic systems are gradually revealing many limitations, mainly in the following aspects: 1. Insufficient magnification stability: Traditional microscopy systems mostly adopt non-telecentric designs. Changes in object distance will cause the imaging magnification to shift, and the measurement error is usually between 1% and 3%, which cannot meet the high-precision measurement requirements of fields such as semiconductor chips and precision mechanical parts. Some single telecentric systems only guarantee object-side telecentricity, while the image-side magnification still fluctuates, making it difficult to achieve deviation-free measurement across the entire range.

[0003] 2. Limited depth of field makes imaging of thick samples difficult: The depth of field of conventional microscope objectives is inversely proportional to the square of the numerical aperture. At high magnification, the depth of field is typically only 1-2 μm, and at low magnification, it is often less than 10 μm. For biological tissue sections, composite material samples, or industrial parts with uneven surfaces exceeding 5 μm in thickness, multiple manual focusing adjustments are required to obtain a complete and clear image. This is not only cumbersome but also prone to losing three-dimensional structural information due to focusing interval errors, affecting the accuracy of the analysis.

[0004] 3. Insufficient focusing efficiency and accuracy: Traditional manual focusing relies on the operator's experience, and the focusing accuracy is greatly affected by human factors and takes a long time; existing automatic focusing systems mostly use a single contrast detection method, which has the problem of misjudging local extreme values, and the focusing time is ≥1 second, which is difficult to meet the needs of rapid detection of batch samples.

[0005] 4. Poor adaptability of lighting systems: Traditional mercury lamp light sources have short lifespans, high energy consumption, and are difficult to switch between wavelengths, and pose a risk of mercury pollution; single-band LED light sources cannot meet the imaging needs of different samples (such as fluorescently labeled biological samples requiring specific wavelength excitation light, and metal material detection requiring red light to enhance contrast), and the uniformity of illumination is mostly below 85%, which easily leads to uneven image brightness and affects the accuracy of defect identification and size measurement.

[0006] 5. Low optical path switching accuracy: Switching between high-magnification and low-magnification imaging often relies on manual lens replacement, which is complex and has large positioning errors. After switching, the optical axis needs to be recalibrated, resulting in low detection efficiency and difficulty in meeting the rapid detection requirements of automated production lines.

[0007] To address the aforementioned issues, there is a need in this field to develop a microscope system that combines dual telecentric distortion-free operation, large depth of field, automatic high-precision focusing, and dual-band uniform illumination characteristics, in order to overcome the bottlenecks of traditional technologies and meet the requirements for high-precision and high-efficiency microscopic detection. Summary of the Invention

[0008] Technical objective: To address the shortcomings of existing microscopic imaging systems, this invention discloses a dual-band LED illumination microscopic imaging system and its usage method.

[0009] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution: A dual-band LED illumination microscopic imaging system includes a dual-band illumination module for providing imaging illumination light, a dual telecentric objective lens for transmitting illumination light to the surface of the sample to be imaged, a high-magnification telecentric imaging lens group and a low-magnification telecentric imaging lens group for receiving reflected light from the surface of the sample to be imaged, and a camera disposed on the image side of the corresponding imaging lens group to receive the image. The high-magnification telecentric imaging lens group and the dual telecentric objective lens constitute a high-magnification imaging system, and the low-magnification telecentric imaging lens group and the dual telecentric objective lens constitute a low-magnification imaging system. The dual-band illumination module includes a red LED light source and a blue LED light source with their optical paths arranged perpendicularly to each other, and a beam combining lens group for combining the illumination light from the light sources.

[0010] Preferably, the beam combiner assembly of the present invention includes a beam splitter, a light homogenizer, and a first beam splitter arranged sequentially along the optical path. The illumination light is combined and enters the dual telecentric objective lens to illuminate the surface of the sample to be imaged. The light reflected from the sample is reflected by the first beam splitter and enters the corresponding imaging lens assembly for imaging. A high-magnification telecentric imaging lens assembly or a low-magnification telecentric imaging lens assembly is arranged on the reflected optical path of the first beam splitter, and a beam splitter assembly for splitting the light path to another imaging lens assembly is arranged on the reflected optical path of the first beam splitter.

[0011] Preferably, the high-magnification telecentric imaging lens group and the low-magnification telecentric imaging lens group of the present invention are arranged in parallel to each other. The beam splitter group includes a second beam splitter and a reflector. The second beam splitter is disposed in the reflected light path of the first beam splitter, and the reflector is disposed in the reflected light path of the second beam splitter. The second beam splitter and the reflector are arranged at a 45° angle with the light path in which they are located. The beam split of the second beam splitter enters the corresponding imaging lens group after being reflected by the reflector.

[0012] Preferably, a multi-dimensional pitch adjustment mechanism for adjusting the pitch angle of the lens relative to the optical path is provided below the first beam splitter, the second beam splitter, and the reflector of the present invention.

[0013] Preferably, the telecentric objective lens of the present invention includes a cemented doublet and a convex lens. The cemented doublet is formed by cementing two types of lenses: one with a refractive index of 1.62 and an Abbe number of 36.35, and the other with a refractive index of 1.59 and an Abbe number of 61.25. The illumination light is focused onto the surface of the sample to be imaged by the convex lens after the on-axis chromatic aberration in the red and blue bands is eliminated by the cemented doublet.

[0014] Preferably, the high-magnification telecentric imaging lens group of the present invention includes a second cemented doublet, a third cemented doublet, and a second convex lens arranged sequentially along the optical path. The second cemented doublet is formed by cementing two types of lenses: one with a refractive index of 1.61 and an Abbe number of 58.58, and the other with a refractive index of 1.49 and an Abbe number of 8.61. The third cemented doublet is formed by cementing two types of lenses: one with a refractive index of 1.72 and an Abbe number of 43.68, and the other with a refractive index of 1.51 and an Abbe number of 64.20. The second convex lens is a plano-convex lens with a radius of curvature of 47.87 on the side closer to the camera.

[0015] Preferably, the low-magnification telecentric imaging lens group of the present invention consists of a fourth cemented doublet lens group, which is formed by cementing two types of lenses: one with a refractive index of 1.67 and an Abbe number of 32.17, and the other with a refractive index of 1.58 and an Abbe number of 46.50.

[0016] Preferably, the cameras of the present invention are all connected to an image sharpness evaluation module, and the bottom of both the high-magnification telecentric imaging lens group and the low-magnification telecentric imaging lens group are provided with an imaging lens group drive mechanism. The image sharpness is detected by the image sharpness evaluation module, and the imaging lens group drive mechanism drives the corresponding imaging lens group to move along the optical axis to adjust the imaging.

[0017] This invention discloses a method of using the aforementioned microscopic imaging system. The illumination light from the dual-band illumination module is combined by a beam combiner and focused by two telecentric objectives to illuminate the surface of the sample to be imaged. The reflected light from the surface of the sample enters the high-magnification imaging system and the low-magnification imaging system respectively, and high-magnification and low-magnification imaging are completed simultaneously by the corresponding cameras. During imaging, the imaging results are detected and evaluated by an image sharpness evaluation module connected to the camera, and the position of the high-magnification telecentric imaging lens group or the low-magnification telecentric imaging lens group on the corresponding optical axis is adjusted according to the evaluation results.

[0018] Beneficial Effects: The dual-band LED illumination microscopic imaging system and its usage method disclosed in this invention have the following beneficial effects: 1. Both the high-magnification and low-magnification imaging systems of this invention employ a dual telecentric design, with an object-side and image-side telecentricity ≤0.2° and a magnification error ≤0.1%, thus solving the measurement deviation problem caused by changes in object distance in traditional systems. In semiconductor chip lead width measurement, the measurement error is ≤0.3μm, meeting the high-precision requirements of the precision manufacturing field.

[0019] 2. This invention enables large depth-of-field imaging, with a depth of field of 40-70μm for high-magnification imaging systems and 150-250μm for low-magnification imaging systems. Combined with Z-axis scanning and image fusion algorithms, it can acquire clear, full-focus images of thick samples in a single pass. When imaging 25μm thick composite material slices, complete and clear interlayer structures can be obtained without manual focusing, improving imaging efficiency by more than 60%.

[0020] 3. The autofocus module of this invention does not require stage linkage or laser positioning. It directly adjusts the objective lens distance through an image sharpness algorithm, while simultaneously fine-tuning the shared variable aperture. The focusing accuracy is ≤0.1μm, which is 10 times better than traditional stage focusing. The focusing time is ≤500ms, which is 50% better than traditional autofocus. In batch sample detection, the focusing time per sample is reduced from 30 seconds to 0.5 seconds, significantly improving detection efficiency.

[0021] 4. The dual-band illumination module of this invention adopts the Köhler illumination system, with illumination uniformity ≥90% and dual-band switching response time ≤50ms. In red light mode, the defect recognition rate of metallic materials is improved by 20%, and in blue light mode, the signal-to-noise ratio of biological sample fluorescence signals is improved by 15%, adapting to diverse sample imaging needs. The LED light source has a lifespan ≥50,000 hours, 25 times longer than mercury lamps, reducing maintenance costs.

[0022] 5. The imaging system of the present invention can achieve simultaneous high and low magnification imaging. With the help of the synchronous calibration function of the optical path adjustment component, the coaxiality error of the two optical paths is controlled within 0.01mm. There is no need for manual intervention to switch the optical path. In the process of industrial inspection, it can simultaneously capture the "microscopic details of the defect" and the "overall location of the defect", which overcomes the process interruption problem of traditional switching design, greatly improves the detection speed, and meets the needs of continuous inspection of automated production lines. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0024] Figure 1 This is a structural diagram of the microscopic imaging system of the present invention; Figure 2 This is an imaging optical path diagram of the microscopic imaging system of the present invention; Among them, 1-Red LED light source, 2-Red collimating lens, 3-Blue LED light source, 4-Blue collimating lens, 5-Beam splitter, 6-Light homogenizer, 7-First beam splitter, 8-Double telecentric objective lens, 9-Second beam splitter, 10-Reflector, 11-High-magnification telecentric imaging lens group, 12-Low-magnification telecentric imaging lens group, 13-XY stage, 14-High-magnification imaging lens group drive motor, 15-Low-magnification imaging lens group drive motor, 16-Camera, 17-Cemented doublet lens group, 18-Convex lens, 19-Second cemented doublet lens group, 20-Third cemented doublet lens group, 21-Second convex lens, 22-Fourth cemented doublet lens group. Detailed Implementation

[0025] Reference will now be made in detail to embodiments of the present disclosure, one or more of which are set forth herein. Each embodiment and example is provided by way of explanation of the apparatus, composition, and materials of the present disclosure, and not by way of limitation. Rather, the following description provides convenient illustrations for implementing exemplary embodiments of the present disclosure. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the teachings of the present disclosure without departing from the scope or spirit of the present disclosure.

[0026] like Figure 1 and Figure 2 As shown, this invention discloses a dual-band LED illumination microscopic imaging system, comprising a dual-band illumination module for providing imaging illumination light, a dual telecentric objective lens 8 for transmitting illumination light to the surface of the sample to be imaged, a high-magnification telecentric imaging lens group 11 and a low-magnification telecentric imaging lens group 12 for receiving reflected light from the surface of the sample to be imaged, and a camera 16 disposed on the image side of the corresponding imaging lens group to receive the image. The high-magnification telecentric imaging lens group 11 and the dual telecentric objective lens 8 constitute a high-magnification imaging system, and the low-magnification telecentric imaging lens group 12 and the dual telecentric objective lens 8 constitute a low-magnification imaging system. The dual-band illumination module includes a red LED light source 1 and a blue LED light source 3 with their optical paths arranged perpendicularly to each other, and a beam combining lens group for combining the illumination light from the light sources.

[0027] The red LED light source 1 of this invention has a dominant wavelength of 630nm, and the blue LED light source has a dominant wavelength of 470nm. Both have an optical power of 5-8W and are equipped with independent aspherical collimating lenses, designated as red collimating lens 2 and blue collimating lens 4, respectively. They are made of H-K9L glass with a 400-700nm thick anti-reflection coating, achieving a transmittance of ≥98% for wavelengths of 630nm and 470nm. After collimation, the beam diameter is 8mm, and the divergence angle is ≤1.5°, ensuring parallelism of the light rays. The red light source is suitable for detecting surface defects in metallic materials, while the blue light source is suitable for fluorescence imaging of biological samples. The lenses are coated with a 400-700nm film and have a focal length of 20mm.

[0028] The beam combiner assembly of the present invention includes a beam splitter 5, a light homogenizer 6, and a first beam splitter 7 arranged sequentially along the optical path. The illumination light is combined and enters the dual telecentric objective lens 8 to illuminate the surface of the sample to be imaged. The light reflected from the sample is reflected by the first beam splitter 7 and enters the corresponding imaging lens assembly for imaging. A high-magnification telecentric imaging lens assembly 11 or a low-magnification telecentric imaging lens assembly 12 is arranged on the reflected light path of the first beam splitter 7. A beam splitter assembly for splitting the light path to another imaging lens assembly is arranged on the reflected light path of the first beam splitter 7.

[0029] The homogenizer 6 converts the collimated LED beam into a uniform surface light source, eliminating the problem of uneven brightness caused by direct light source illumination and ensuring that the uniformity of the sample surface illumination is ≥98%. In the embodiments of the present invention, the specifications of the homogenizer 6 are shown in Table 1. The homogenized light source is combined by the first beam splitter 7. The first beam splitter 7 adopts a quartz substrate coating design, and the transmittance and reflectance of 470nm blue light and 630nm red light are both 50%±5%, ensuring that the energy of the two light sources is balanced and combined. After beam combining, the coaxiality error of the beam is ≤0.005mm.

[0030]

[0031] The combined light beam is projected onto the surface of the sample to be imaged through the double telecentric objective lens 8. The double telecentric objective lens 8 includes a cemented doublet lens group 17 and a convex lens 18. The cemented doublet lens group 17 is formed by cementing two types of lenses: one with a refractive index of 1.62 and an Abbe number of 36.35, and the other with a refractive index of 1.59 and an Abbe number of 61.25. The cemented doublet lens has a focal length of 164.36 mm, which can effectively eliminate chromatic aberration in the red and blue bands. The convex lens is made of H-ZK3 material and has a focal length of 45.19 mm, ensuring the focusing accuracy of the light beam. After the illumination light is eliminated by the cemented doublet lens group 17 to eliminate chromatic aberration in the red and blue bands, it is focused onto the surface of the sample to be imaged by the convex lens 18, meeting the intensity requirements of the reflected light from the sample and ensuring the signal-to-noise ratio of the image. When it is necessary to perform three-dimensional scanning of the sample to be imaged or to image different areas, the sample to be imaged can be placed on the XY stage 13. By moving the sample, imaging of different areas can be achieved. The XY stage 13 preferably adopts a cross roller guide structure with parameters that meet the requirements of a 100mm×100mm movement range in the X and Y axes, a minimum step size of 0.1μm, and a repeatability of ±0.5μm, which meets the requirements of full-area scanning of large samples. It can also be equipped with fixtures corresponding to the sample to fix different samples.

[0032] The reflected light from the sample to be imaged is imaged by a high-magnification imaging system and a low-magnification imaging system. An aperture stop (not shown in the figure) is set at the back focal plane of the objective lens 8. The aperture of the aperture stop can be adjusted. By constraining the object-side principal ray to be parallel to the optical axis, the object-side telecentricity is achieved to be ≤0.1°. The high-magnification telecentric imaging lens group 11 and the low-magnification telecentric imaging lens group 12 of the present invention are arranged parallel to each other. The high-magnification telecentric imaging lens group 11 and the low-magnification telecentric imaging lens group 12 achieve image-side telecentricity. The beam splitter group includes a second beam splitter 9 and a reflector 10. The second beam splitter 9 is set in the reflected light path of the first beam splitter 7, and the reflector 10 is set in the reflected light path of the second beam splitter 9. The second beam splitter 9 and the reflector 10 are set at a 45° angle with their respective light paths. The beam splitter light of the second beam splitter 9 is reflected by the reflector 10 and enters the corresponding imaging lens group.

[0033] Below the first beam splitter 7, the second beam splitter 9, and the reflector 10, a multi-dimensional pitch adjustment mechanism is provided for adjusting the pitch angle of the lens relative to the optical path. The multi-dimensional pitch adjustment mechanism is used to ensure the consistency of the optical path of the imaging system. The pitch angle of the lens can be adjusted using existing adjustment methods. In the embodiment of the present invention, a "three-point positioning" design is adopted using fine-tooth screws located below the lens to adjust the angles of the first beam splitter, the second beam splitter, and the 45° reflector respectively.

[0034] First beam splitter adjustment: ±2° pitch angle adjustment is achieved through two sets of M3×0.25 fine thread screws to ensure that the illumination light is accurately focused on the center of the sample surface after passing through the lens group, while ensuring that the sample reflected light is reflected back along the original optical path to the second beam splitter with a reflection efficiency ≥95%; Second beam splitter adjustment: Fixed at 45°, the pitch angle is finely adjusted by a set of fine screws so that the angle between the light path transmitted to the low magnification system and the light path reflected to the 45° mirror is ≤0.01°, ensuring that the two optical axes are parallel; 45° Reflector Adjustment: ±1° pitch angle adjustment is achieved through two sets of fine-threaded screws, which precisely guides the reflected light from the second beam splitter to the high-magnification imaging system, ensuring that the reflected light axis coincides with the object-side telecentric axis of the high-magnification objective lens, with a deviation ≤0.005mm.

[0035] The high-magnification telecentric imaging lens group 11 of the present invention includes a second cemented doublet lens group 19, a third cemented doublet lens group 20, and a second convex lens 21 arranged sequentially along the optical path. The second cemented doublet lens group 19 is formed by cementing two types of lenses: one with a refractive index of 1.61 and an Abbe number of 58.58, and the other with a refractive index of 1.49 and an Abbe number of 8.61. The third cemented doublet lens group 20 is formed by cementing two types of lenses: one with a refractive index of 1.72 and an Abbe number of 43.68, and the other with a refractive index of 1.51 and an Abbe number of 64.20. The second convex lens 21 is a plano-convex lens with a radius of curvature of 47.87 on the side closer to the camera.

[0036] The dual telecentric objective lens 8 and the high-magnification telecentric imaging lens group 11 of this invention constitute a high-magnification imaging system. The optical parameters of each lens in the system are shown in Table 2: object-side telecentricity ≤ 0.1°, image-side telecentricity ≤ 0.1°, magnification 10×, magnification error ≤ 1%, depth of field 40-70μm, and resolution ≤ 0.5μm (630nm band).

[0037]

[0038] The low-magnification imaging system and the high-magnification imaging system share the double telecentric objective lens 8. The magnification is switched only by changing the low-magnification telecentric imaging lens group. The low-magnification telecentric imaging lens group 12 of the present invention is composed of a fourth doublet lens group 22, which is formed by bonding two types of lenses with a refractive index of 1.67 and an Abbe number of 32.17 and a refractive index of 1.58 and an Abbe number of 46.50.

[0039] In the embodiments of the present invention, the low-magnification imaging system formed by the dual telecentric objective lens 8 and the low-magnification telecentric imaging lens group 12 has an object-side telecentricity ≤0.2°, an image-side telecentricity ≤0.2°, a magnification of 5×, a magnification error ≤0.2%, a depth of field of 150-250μm, and a field of view ≥5mm×5mm, which is suitable for large sample full-domain scanning detection. The parameters of the low-magnification imaging system are shown in Table 3.

[0040]

[0041] To ensure image quality, each camera 16 of this invention is connected to an image sharpness evaluation module. Both the high-magnification telecentric imaging lens group 11 and the low-magnification telecentric imaging lens group 12 are equipped with imaging lens group drive mechanisms at their bottoms. The image sharpness evaluation module detects the image sharpness, and the imaging lens group drive mechanisms move the corresponding imaging lens groups along the optical axis to adjust the image. The imaging lens group drive mechanisms use independent precision voice coil motors to drive the movement of the lens groups, referred to as the high-magnification imaging lens group drive motor 14 and the low-magnification imaging lens group drive motor 15. The voice coil motors are responsible for driving the imaging lens groups to move along the optical axis, with a stroke range of ±5mm, a minimum step size of 0.01μm, and a response time not exceeding 10ms. To ensure precise positioning, the system integrates a grating ruler with a resolution of 0.05μm for real-time acquisition of objective lens position data. This data is then fed back to the PID controller, forming a closed-loop feedback loop. Combined with image sharpness evaluation results, this enables focusing accuracy ≤0.1μm, focusing time ≤500ms, and overshoot ≤1μm. High and low magnification objectives can be focused synchronously or independently to adapt to the focusing requirements of different samples and adjust the position of the corresponding imaging lens group.

[0042] This invention uses a CMOS camera for imaging. The CMOS camera parameters are: 5472×3648 pixels, pixel size 2.4μm×2.4μm, and quantum efficiency ≥60%. During the adjustment of the imaging lens group position, real-time image capture is performed using both high-magnification and low-magnification CMOS cameras, with a sampling frequency of at least 30 frames per second. The Tenengrad gradient algorithm is applied to calculate the image sharpness evaluation function. This algorithm, by acquiring the gradient values ​​of image edges, improves the sensitivity to sample detail changes by 20% compared to the traditional Sobel algorithm, and has a signal-to-noise ratio of over 30dB. It effectively prevents misjudgments of local extrema caused by uneven illumination, ensuring the accuracy of the detection and evaluation results.

[0043] This invention discloses a method of using the aforementioned microscopic imaging system. The illumination light from the dual-band illumination module is combined by a beam combiner and focused by two telecentric objectives to illuminate the surface of the sample to be imaged. The reflected light from the surface of the sample enters the high-magnification imaging system and the low-magnification imaging system respectively, and high-magnification and low-magnification imaging are completed simultaneously by the corresponding cameras. During imaging, the imaging results are detected and evaluated by an image sharpness evaluation module connected to the camera, and the position of the high-magnification telecentric imaging lens group or the low-magnification telecentric imaging lens group on the corresponding optical axis is adjusted according to the evaluation results.

[0044] The operation of the microscopic imaging system of this invention is achieved through a control system that enables the system operation between components, realizing automated imaging of samples. The control system is based on an STM32H743 microprocessor and is connected to a stepper motor drive module via an RS485 bus. This control module controls the motor of the XY stage to move the sample to be imaged along the X and Y axes and switch the optical path. The brightness of the LED light source of the dual-band illumination module is controlled by a DC-DC drive module. The automatic focusing closed-loop control is achieved through a voice coil motor drive module in conjunction with an image sharpness evaluation module. The imaging system of this invention supports three-dimensional scanning, automatic focusing, and image fusion. It is compatible with the imaging and detection needs of samples of different thicknesses and is applicable to multiple fields such as biomedicine, precision manufacturing, and industrial inspection. It has strong versatility and promotional value.

[0045] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A microscopic imaging system with dual-band LED illumination, characterized in that, The system includes a dual-band illumination module for providing imaging illumination light, a dual telecentric objective lens (8) for transmitting illumination light to the surface of the sample to be imaged, a high-magnification telecentric imaging lens group (11) and a low-magnification telecentric imaging lens group (12) for receiving reflected light from the surface of the sample to be imaged, and a camera (16) set on the image side of the corresponding imaging lens group to receive the image. The high-magnification telecentric imaging lens group (11) and the dual telecentric objective lens (8) constitute a high-magnification imaging system, and the low-magnification telecentric imaging lens group (12) and the dual telecentric objective lens (8) constitute a low-magnification imaging system. The dual-band illumination module includes a red LED light source (1) and a blue LED light source (3) with their optical paths perpendicular to each other, and a beam combiner lens group for combining the illumination light from the light source.

2. The dual-band LED illumination microscopic imaging system according to claim 1, characterized in that, The beam combiner group includes a beam splitter (5), a light homogenizer (6), and a first beam splitter (7) arranged sequentially along the optical path. The illumination light is combined and enters the double telecentric objective lens (8) to illuminate the surface of the sample to be imaged. The sample reflected light is reflected by the first beam splitter (7) and enters the corresponding imaging lens group for imaging. A high-magnification telecentric imaging lens group (11) or a low-magnification telecentric imaging lens group (12) is set on the reflected light path of the first beam splitter (7). A beam splitter group is set on the reflected light path of the first beam splitter (7) to split the light path to another imaging lens group.

3. The dual-band LED illumination microscopic imaging system according to claim 2, characterized in that, The high-magnification telecentric imaging lens group (11) and the low-magnification telecentric imaging lens group (12) are arranged in parallel to each other. The beam splitter group includes a second beam splitter (9) and a reflector (10). The second beam splitter (9) is arranged on the reflected light path of the first beam splitter (7), and the reflector (10) is arranged on the reflected light path of the second beam splitter (9). The second beam splitter (9) and the reflector (10) are arranged at a 45° angle with the light path. The beam split of the second beam splitter (9) enters the corresponding imaging lens group after being reflected by the reflector (10).

4. A dual-band LED illumination microscopic imaging system according to claim 3, characterized in that, A multi-dimensional pitch adjustment mechanism for adjusting the pitch angle of the lens relative to the optical path is provided below the first beam splitter (7), the second beam splitter (9), and the reflector (10).

5. A dual-band LED illumination microscopic imaging system according to claim 1, characterized in that, The dual telecentric objective (8) includes a cemented doublet (17) and a convex lens (18). The cemented doublet (17) is formed by cementing two types of lenses: one with a refractive index of 1.62 and an Abbe number of 36.35, and the other with a refractive index of 1.59 and an Abbe number of 61.

25. The illumination light is focused onto the surface of the sample to be imaged by the convex lens (18) after the on-axis chromatic aberration in the red and blue bands is eliminated by the cemented doublet (17).

6. A dual-band LED illumination microscopic imaging system according to claim 1, characterized in that, The high-magnification telecentric imaging lens group (11) includes a second cemented doublet group (19), a third cemented doublet group (20), and a second convex lens (21) arranged sequentially along the optical path. The second cemented doublet group (19) is formed by cementing two types of lenses with a refractive index of 1.61 and an Abbe number of 58.58 and a refractive index of 1.49 and an Abbe number of 8.

61. The third cemented doublet group (20) is formed by cementing two types of lenses with a refractive index of 1.72 and an Abbe number of 43.68 and a refractive index of 1.51 and an Abbe number of 64.

20. The second convex lens (21) is a plano-convex lens with a radius of curvature of 47.87 on the side closest to the camera.

7. A dual-band LED illumination microscopic imaging system according to claim 1, characterized in that, The low-magnification telecentric imaging lens group (12) consists of a fourth doublet lens group (22), which is formed by bonding two types of lenses: one with a refractive index of 1.67 and an Abbe number of 32.17, and the other with a refractive index of 1.58 and an Abbe number of 46.

50.

8. A dual-band LED illumination microscopic imaging system according to claim 1, characterized in that, Each camera (16) is connected to an image sharpness evaluation module. The bottom of both the high-magnification telecentric imaging lens group (11) and the low-magnification telecentric imaging lens group (12) is provided with an imaging lens group drive mechanism. The image sharpness is detected by the image sharpness evaluation module, and the imaging lens group drive mechanism drives the corresponding imaging lens group to move along the optical axis to adjust the imaging.

9. A method of using the microscopic imaging system according to any one of claims 1-8, characterized in that, The illumination light from the dual-band illumination module is combined by a beam combiner and focused by two telecentric objectives onto the surface of the sample to be imaged. The reflected light from the sample surface enters the high-magnification imaging system and the low-magnification imaging system respectively, and the corresponding cameras simultaneously complete high-magnification and low-magnification imaging. During imaging, the imaging results are detected and evaluated by the image sharpness evaluation module connected to the camera, and the position of the high-magnification telecentric imaging lens group or the low-magnification telecentric imaging lens group on the corresponding optical axis is adjusted according to the evaluation results.

Images