Illuminating system of structured light microscope

Abstract

The illumination system comprises a light source and a digital micro-mirror device used for generating different phase modulation images, an aberration-eliminating combined lens is arranged between the digital micro-mirror device and a microscope main body, the digital micro-mirror device is arranged at the front focus position of the aberration-eliminating combined lens, and the digital micro-mirror device is arranged at the front focus position of the aberration-eliminating combined lens. The rear focus of the aberration-eliminating combined lens coincides with the focus of the objective lens of the microscope main body in the direction of the digital micro-mirror device, the aberration-eliminating combined lens comprises an aberration-eliminating lens group, the focal length f of the aberration-eliminating lens group is 45-70mm, f and the diagonal length X of the digital micro-mirror device meet the following relation: X is greater than or equal to 0.125 * f, the digital micro-mirror device has the advantages that a larger area can be imaged during single imaging while the digital micro-mirror device is used for stably switching modulation images with different phases, and more accurate analysis and measurement are facilitated.

Description

Technical Field

[0001] The invention relates to an illumination system for a microscope, in particular to an illumination system for a structured light microscope. Background Art

[0002] The working principle of structured light microscope is to modulate the illumination light source to generate a set of modulated lights of different phases to illuminate the sample, and then calculate the images modulated by this set of modulated lights of different phases, extract the information of the focal plane from the data, and reconstruct the slice image and three-dimensional image. The generated image quality is higher than that of conventional microscope and close to that of confocal microscope, and it has a simple structure and fast imaging speed, which has great advantages in terms of cost performance.

[0003] There are two main types of devices for modulating illumination light sources for structured light microscopes on the market: one uses a grating as a spatial light modulator, and the other uses a digital micromirror device as a spatial light modulator. The spatial light modulator with a grating structure is relatively easy to process, and its size can be easily enlarged, making it easier to achieve illumination of a large field of view. However, when changing the modulated images of different phases, piezoelectric ceramics are required to drive the grating shift. This structure is relatively unstable and is prone to produce black and white stripes during image reconstruction. The spatial light modulator using a digital micromirror device is relatively easy to achieve stable switching of modulated images of different phases, but it is difficult to increase its size due to the difficulty of processing. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an illumination system for a structured light microscope which can stably switch modulated images of different phases and has a large field of view illumination.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: an illumination system of a structured light microscope, comprising a light source and a digital micromirror device for generating modulated images of different phases, an aberration-correcting combination lens is arranged between the digital micromirror device and a microscope body, the digital micromirror device is arranged at a front focal position of the aberration-correcting combination lens, a rear focal point of the aberration-correcting combination lens coincides with a focal point of an objective lens of the microscope body in a direction toward the digital micromirror device, the aberration-correcting combination lens is used to correct the position deviation of the modulated image of the sample surface projected by the digital micromirror device on the sample stage of the microscope body at different wavelengths within the visible light range, the aberration-correcting combination lens comprises an aberration-correcting lens group, the focal length f of the aberration-correcting lens group is 45 mm to 70 mm, and the focal length f of the aberration-correcting lens group and the diagonal length X of the digital micromirror device meet the following relationship: X≥0.125×f.

[0006] Compared with the prior art, the advantage of the present invention lies in that an aberration-correcting combined lens capable of correcting the positional offset of the modulated image of the sample surface projected by the digital micromirror device on the sample stage of the microscope body at different wavelengths in the visible light range is arranged between the digital micromirror device and the microscope body, and a specific focal length of the aberration-correcting lens group and a specific relationship between the focal length of the aberration-correcting lens group and the diagonal length of the digital micromirror device are selected. While using the digital micromirror device to stably realize the switching of modulated images of different phases, the range of a single image is increased, a larger area can be imaged in a single imaging, more comprehensive spatial information is provided, the number of times the sample or lens is moved is reduced and efficiency is improved, the scanning speed can be increased in the application of rapid scanning and splicing, and the overall structure of the sample and the relationship between different areas are observed, thereby obtaining more comprehensive information and clearer details, which is conducive to more accurate analysis and measurement.

[0007] In one embodiment, the aberration-correcting combined lens can be a single aberration-correcting lens group, the digital micromirror device is arranged at the front focal position of the aberration-correcting lens group, and the rear focal point of the aberration-correcting lens group coincides with the focal point of the objective lens of the microscope body in the direction toward the digital micromirror device.

[0008] In another embodiment, the aberration-correcting combined lens may also be composed of the aberration-correcting lens group and an optical path extension structure disposed between the aberration-correcting lens group and the microscope body, the optical path extension structure being composed of a first lens group and a second lens group, the digital micromirror device being disposed at the front focal position of the aberration-correcting lens group, the front focal point of the first lens group coincides with the rear focal point of the aberration-correcting lens group, and the rear focal point of the second lens group coincides with the focal point of the objective lens of the microscope body in the direction toward the digital micromirror device. The main function of setting the optical path extension structure is to increase the optical path, because in traditional microscope applications the objective lens needs to be connected to the front of the frame of the microscope body, and therefore the illumination system usually requires an optical path extension structure to extend the optical path.

[0009] Preferably, the rear focus of the first lens group and the front focus of the second lens group coincide with a coincidence point, and the first lens group and the second lens group are symmetrical about the coincidence point. Symmetrical design can reduce the cost of parts as much as possible.

[0010] Preferably, a reflector for bending the light path is provided between the first lens group and the second lens group. Using a reflector to bend the light path can avoid the situation where the light path in one direction is too long.

[0011] Preferably, the aberration-correcting lens group is composed of a first lens, a triplet lens, a doublet lens, a second lens and a third lens arranged in sequence from the digital micromirror device to the microscope body, the optical focal powers of the first lens, the second lens and the third lens are all positive, and the optical focal powers of the triplet lens and the doublet lens are all negative.

[0012] Preferably, the triplet lens is composed of a first single lens with a negative focal length, a second single lens with a positive focal length and a third single lens with a negative focal length, which are arranged in sequence from the digital micromirror device to the microscope body, and the doublet lens is composed of a fourth single lens with a negative focal length and a fifth single lens with a positive focal length, which are arranged in sequence from the digital micromirror device to the microscope body.

[0013] Preferably, the first single lens is a meniscus lens with a convex surface facing the digital micromirror device, the second single lens is a biconvex lens, and the third single lens is a biconcave lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the structured light microscope of the present invention; Figure 2 It is a schematic diagram of the partial structure of the illumination system and the microscope body of the structured light microscope of Example 1 in the embodiment of the present invention; Figure 3 It is an enlarged structural diagram of a digital micromirror device and an aberration-correcting lens group in Example 1 of an embodiment of the present invention; Figure 4 It is a partial structural diagram of the digital micromirror device, the aberration-free lens group and the microscope body in Example 2 of the embodiment of the present invention; Figure 5 The structure diagram of the digital micromirror device and the aberration-correcting lens group in the third embodiment of the present invention is shown; Figure 6 The structure diagram of four digital micromirror devices and aberration-correcting lens groups in the embodiments of the present invention is shown in FIG.

[0015] Description of reference numerals: 1. Light source; 2. Digital micromirror device; 4. Aberration-correcting lens group; 41. First lens; 42. Triplet lens; L1. First single lens; L2. Second single lens; L3. Third single lens; 43. Doublet lens; L4. Fourth single lens; L5. Fifth single lens; 44. Second lens; 45. Third lens; 7. Light path extension structure; 71. First lens group; 72. Second lens group; 73. Reflector; 8. Microscope body; 81. Sample stage; 82. Objective lens; 83. Spectroscope; 84. Imaging system; 85. Camera. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below with reference to the accompanying drawings.

[0017] In this embodiment, the term “front” refers to a direction close to the digital micromirror device 2 , and the term “rear” refers to a direction close to the microscope body 8 .

[0018] Example: Figure 1 As shown, an illumination system of a structured light microscope comprises a light source 1 and a digital micromirror device 2 for generating images modulated with different phases, an aberration-correcting combined lens is arranged between the digital micromirror device 2 and a microscope body 8, the microscope body 8 comprises a sample stage 81, an objective lens 82, a spectroscope 83, an imaging system 84 and a camera 85, the aberration-correcting combined lens is used to correct the position deviation of the modulated image of the sample surface projected on the sample stage 81 of the microscope body 8 by the digital micromirror device 2 at different wavelengths within the visible light range, the aberration-correcting combined lens comprises an aberration-correcting lens group 4, the focal length f of the aberration-correcting lens group 4 is 45 mm to 70 mm, and the focal length f of the aberration-correcting lens group 4 and the diagonal length X of the digital micromirror device 2 meet the following relationship: X≥0.125×f.

[0019] The aberration-correcting combined lens can be a single aberration-correcting lens group 4 , or can be a aberration-correcting lens group 4 plus an optical path extension structure 7 . Figure 1 The aberration-correcting combination lens of the present embodiment shown is composed of an aberration-correcting lens group 4 and an optical path extension structure 7 arranged between the aberration-correcting lens group 4 and a microscope body 8. The optical path extension structure 7 is composed of a first lens group 71 and a second lens group 72. A reflector 73 for bending the optical path is arranged between the first lens group 71 and the second lens group 72. The first lens group 71 and the second lens group 72 coincide at a coincidence point. The first lens group 71 and the second lens group 72 are symmetrical about the coincidence point. The front focus of the first lens group 71 coincides with the rear focus of the aberration-correcting lens group 4. The rear focus of the second lens group 72 coincides with the focus of the objective lens 82 in the direction toward the digital micromirror device 2. The digital micromirror device 2 is arranged at the front focus position of the aberration-correcting lens group 4. Figure 1 It can be seen that the light emitted from the second lens group 72 is incident on the beam splitter 83, is reflected into the objective lens 82, and then illuminates the sample surface on the sample stage 81. The light emitted from the sample surface is imaged on the camera 85 through the imaging system 84.

[0020] The aberration-correcting lens group 4 is composed of a first lens 41, a triplet lens 42, a doublet lens 43, a second lens 44 and a third lens 45 arranged in sequence from the digital micromirror device 2 to the microscope body 8; the optical focal powers of the first lens 41, the second lens 44 and the third lens 45 are all positive optical focal powers, and the optical focal powers of the triplet lens 42 and the doublet lens 43 are all negative optical focal powers. The triplet lens 42 is composed of a first single lens L1 with a negative focal length, a second single lens L2 with a positive focal length and a third single lens L3 with a negative focal length arranged in sequence from the digital micromirror device 2 to the microscope body 8. The first single lens L1 is a meniscus lens with the convex surface facing the digital micromirror device 2, the second single lens L2 is a double convex lens, and the third single lens L3 is a double concave lens. The doublet lens 43 is composed of a fourth single lens L4 with a negative focal length and a fifth single lens L5 with a positive focal length arranged in sequence from the digital micromirror device 2 to the microscope body 8.

[0021] The following are four specific examples of the embodiments of the present invention. In each example, the value of the curvature radius R of the spherical surface convex toward the light source 1 is positive, and the value of the curvature radius R of the spherical surface convex toward the microscope body 8 is negative.

[0022] Example 1: Figure 2 and Figure 3 As shown, along the light propagation direction, the first spherical surface to the thirteenth spherical surface describe the lens structure of the aberration-correcting lens group 4, the first spherical surface is close to the digital micromirror device 2, and the thirteenth spherical surface is close to the optical path extension structure 7. The diagonal length X of the digital micromirror device 2 is selected to be 5.7 mm, the center of the digital micromirror device 2 is placed at the front focus position of the aberration-correcting lens group 4, the distance from the first spherical surface is 25.1 mm, the focal length f of the aberration-correcting lens group 4 is 45 mm, and the specific parameters of the aberration-correcting lens group 4 are shown in Table 1.

[0023] In Table 1, the first spherical surface is the light incident surface of the first lens 41, the second spherical surface is the light exit surface of the first lens 41, the third spherical surface is the light incident surface of the first single lens L1, the fourth spherical surface is the light incident surface of the second single lens L2, the fifth spherical surface is the light incident surface of the third single lens L3, the sixth spherical surface is the light exit surface of the third single lens L3, the seventh spherical surface is the light incident surface of the fourth single lens L4, the eighth spherical surface is the light incident surface of the fifth single lens L5, the ninth spherical surface is the light exit surface of the fifth single lens L5, the tenth spherical surface is the light incident surface of the second lens 44, the eleventh spherical surface is the light exit surface of the second lens 44, the twelfth spherical surface is the light incident surface of the third lens 45, and the thirteenth spherical surface is the light exit surface of the third lens 45.

[0024] Table 1

[0025] The aberration-free combination lens of Example 1 is composed of an aberration-free lens group 4 and an optical path extension structure 7. The first lens group 71 and the second lens group 72 of the optical path extension structure 7 are both double-cemented lenses with a lens thickness of 6 mm. The distance from the front focus of the first lens group 71 to the center of the front surface of the first lens group 71 is 178.8 mm, the distance from the back focus of the first lens group 71 to the center of the back surface of the first lens group 71 is 177.4 mm, the distance from the front focus of the second lens group 72 to the center of the front surface of the second lens group 72 is 177.4 mm, and the distance from the back focus of the second lens group 72 to the center of the back surface of the second lens group 72 is 178.8 mm, extending the optical path of the entire illumination system by 724.4 mm. After passing through the optical path extension structure 7, the light enters the objective lens 82 and irradiates the sample surface on the sample stage 81. The light emitted from the sample surface is imaged on the camera 85 through the imaging system 84, and the illumination of the 25.3 mm field of view can be achieved.

[0026] Example 2: If Figure 4 As shown in FIG. 1 , along the light propagation direction, the first spherical surface to the thirteenth spherical surface describe the lens structure of the aberration-correcting lens group 4, the first spherical surface is close to the digital micromirror device 2, and the thirteenth spherical surface is close to the microscope body 8. The diagonal length X of the digital micromirror device 2 is selected as 6.3 mm, and the center of the digital micromirror device 2 is placed at the front focus position of the aberration-correcting lens group 4, where the distance from the first spherical surface is 29.6 mm, and the focal length f of the aberration-correcting lens group 4 is 50 mm. The specific parameters of the aberration-correcting lens group 4 are shown in Table 2.

[0027] In Table 2, the first spherical surface is the light incident surface of the first lens 41, the second spherical surface is the light exit surface of the first lens 41, the third spherical surface is the light incident surface of the first single lens L1, the fourth spherical surface is the light incident surface of the second single lens L2, the fifth spherical surface is the light incident surface of the third single lens L3, the sixth spherical surface is the light exit surface of the third single lens L3, the seventh spherical surface is the light incident surface of the fourth single lens L4, the eighth spherical surface is the light incident surface of the fifth single lens L5, the ninth spherical surface is the light exit surface of the fifth single lens L5, the tenth spherical surface is the light incident surface of the second lens 44, the eleventh spherical surface is the light exit surface of the second lens 44, the twelfth spherical surface is the light incident surface of the third lens 45, and the thirteenth spherical surface is the light exit surface of the third lens 45.

[0028] Table 2

[0029] The aberration-free combination lens of Example 2 is a single aberration-free lens group 4, and no optical path extension structure is used. After the light enters the objective lens 82, it illuminates the sample surface on the sample stage 81. The light emitted from the sample surface is imaged on the camera 85 through the imaging system 84, which can achieve illumination of a 24.8mm field of view.

[0030] Example 3: Figure 5 As shown, along the light propagation direction, the first spherical surface to the thirteenth spherical surface describe the lens structure of the aberration-correcting lens group 4, the first spherical surface is close to the digital micromirror device 2, and the thirteenth spherical surface is close to the microscope body 8. The diagonal length X of the digital micromirror device 2 is selected to be 7.5 mm, the center of the digital micromirror device 2 is placed at the front focus position of the aberration-correcting lens group 4, the distance from the first spherical surface is 40.4 mm, the focal length f of the aberration-correcting lens group 4 is 60 mm, and the specific parameters of the aberration-correcting lens group 4 are shown in Table 3.

[0031] In Table 3, the first spherical surface is the light incident surface of the first lens 41, the second spherical surface is the light exit surface of the first lens 41, the third spherical surface is the light incident surface of the first single lens L1, the fourth spherical surface is the light incident surface of the second single lens L2, the fifth spherical surface is the light incident surface of the third single lens L3, the sixth spherical surface is the light exit surface of the third single lens L3, the seventh spherical surface is the light incident surface of the fourth single lens L4, the eighth spherical surface is the light incident surface of the fifth single lens L5, the ninth spherical surface is the light exit surface of the fifth single lens L5, the tenth spherical surface is the light incident surface of the second lens 44, the eleventh spherical surface is the light exit surface of the second lens 44, the twelfth spherical surface is the light incident surface of the third lens 45, and the thirteenth spherical surface is the light exit surface of the third lens 45.

[0032] Table 3

[0033] This example 3 only includes a digital micromirror device 2 and an aberration-correcting lens group 4, and the rear part can be directly connected to the microscope body 8 if space permits, or can be connected to an optical path extension structure 7. After the light enters the objective lens 82, it irradiates the sample surface on the sample stage 81. The light emitted from the sample surface is imaged on the camera 85 through the imaging system 84, and illumination within a 25.0 mm field of view can be achieved.

[0034] Example 4: Figure 6 As shown, along the light propagation direction, the first spherical surface to the thirteenth spherical surface describe the lens structure of the aberration-correcting lens group 4, the first spherical surface is close to the digital micromirror device 2, and the thirteenth spherical surface is close to the microscope body 8. The diagonal length X of the digital micromirror device 2 is selected as 9.0 mm, the center of the digital micromirror device 2 is placed at the front focus position of the aberration-correcting lens group 4, the distance from the first spherical surface is 55.2 mm, the focal length f of the aberration-correcting lens group 4 is 70 mm, and the specific parameters of the aberration-correcting lens group 4 are shown in Table 4.

[0035] In Table 4, the first spherical surface is the light incident surface of the first lens 41, the second spherical surface is the light exit surface of the first lens 41, the third spherical surface is the light incident surface of the first single lens L1, the fourth spherical surface is the light incident surface of the second single lens L2, the fifth spherical surface is the light incident surface of the third single lens L3, the sixth spherical surface is the light exit surface of the third single lens L3, the seventh spherical surface is the light incident surface of the fourth single lens L4, the eighth spherical surface is the light incident surface of the fifth single lens L5, the ninth spherical surface is the light exit surface of the fifth single lens L5, the tenth spherical surface is the light incident surface of the second lens 44, the eleventh spherical surface is the light exit surface of the second lens 44, the twelfth spherical surface is the light incident surface of the third lens 45, and the thirteenth spherical surface is the light exit surface of the third lens 45.

[0036] Table 4

[0037] This example 4 is only a digital micromirror device 2 and an aberration-correcting lens group 4, and the rear part can be directly connected to the microscope body 8 if space permits, or can be connected to the optical path extension structure 7. After the light enters the objective lens 82, it irradiates the sample surface on the sample stage 81. The light emitted from the sample surface is imaged on the camera 85 through the imaging system 84, and the illumination of the field of view range of 25.7mm can be achieved.

Claims

1. An illumination system for a structured light microscope, comprising a light source and a digital micromirror device for generating different phase modulated images, characterized in that: An aberration-correcting combined lens is arranged between the digital micromirror device and the microscope body, the digital micromirror device is arranged at the front focal position of the aberration-correcting combined lens, the rear focal point of the aberration-correcting combined lens coincides with the focal point of the objective lens of the microscope body in the direction toward the digital micromirror device, the aberration-correcting combined lens is used to correct the position deviation of the modulated image of the digital micromirror device projected on the sample surface on the sample stage of the microscope body at different wavelengths within the visible light range, the aberration-correcting combined lens comprises an aberration-correcting lens group, the focal length f of the aberration-correcting lens group is 45 mm to 70 mm, and the focal length f of the aberration-correcting lens group and the diagonal length X of the digital micromirror device meet the following relationship: X≥0.125×f.

2. The illumination system for a structured light microscope according to claim 1, characterized in that: The aberration-correcting combined lens is a single aberration-correcting lens group, the digital micromirror device is arranged at the front focal position of the aberration-correcting lens group, and the rear focal point of the aberration-correcting lens group coincides with the focal point of the objective lens of the microscope body in the direction toward the digital micromirror device.

3. The illumination system for a structured light microscope according to claim 1, characterized in that: The aberration-correcting combined lens is composed of the aberration-correcting lens group and an optical path extension structure arranged between the aberration-correcting lens group and the microscope body, the optical path extension structure is composed of a first lens group and a second lens group, the digital micromirror device is arranged at the front focus position of the aberration-correcting lens group, the front focus of the first lens group coincides with the rear focus of the aberration-correcting lens group, and the rear focus of the second lens group coincides with the focus of the objective lens of the microscope body in the direction toward the digital micromirror device.

4. The illumination system for a structured light microscope according to claim 3, characterized in that: The rear focus of the first lens group and the front focus of the second lens group coincide with a coincidence point, and the first lens group and the second lens group are symmetrical about the coincidence point.

5. The illumination system for a structured light microscope according to claim 4, characterized in that: A reflector for bending the light path is arranged between the first lens group and the second lens group.

6. The illumination system for a structured light microscope according to any one of claims 1 to 5, characterized in that: The aberration-correcting lens group is composed of a first lens, a triplet lens, a doublet lens, a second lens and a third lens arranged in sequence from the digital micromirror device to the microscope body. The optical focal powers of the first lens, the second lens and the third lens are all positive, and the optical focal powers of the triplet lens and the doublet lens are all negative.

7. The illumination system for a structured light microscope according to claim 6, characterized in that: The triplet lens is composed of a first single lens with a negative focal length, a second single lens with a positive focal length, and a third single lens with a negative focal length, which are arranged in sequence from the digital micromirror device to the microscope body, and the doublet lens is composed of a fourth single lens with a negative focal length and a fifth single lens with a positive focal length, which are arranged in sequence from the digital micromirror device to the microscope body.

8. The illumination system for a structured light microscope according to claim 7, characterized in that: The first single lens is a meniscus lens with a convex surface facing the digital micromirror device, the second single lens is a double convex lens, and the third single lens is a double concave lens.

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