An illumination system for a structured light microscope

Abstract

The present invention discloses an illumination system for a structured light microscope, which includes a light source and a digital micromirror device for generating images with different phase modulations. An aberration-corrected combined lens is disposed between the digital micromirror device and the microscope main body. The digital micromirror device is disposed at the front focal position of the aberration-corrected combined lens, and the rear focal point of the aberration-corrected combined lens coincides with the focal point in the direction of the objective lens of the microscope main body facing the digital micromirror device. The aberration-corrected combined lens includes an aberration-corrected lens group, and the focal length f of the aberration-corrected lens group is 45 mm to 70 mm. The f and the diagonal length X of the digital micromirror device satisfy the following relationship: X ≥ 0.125 × f. The advantage is that while stably realizing the switching of images with different phase modulations by using the digital micromirror device, a larger area can be imaged in a single imaging, which helps to more accurately analyze and measure.

Description

Technical Field

[0001] The present invention relates to an illumination system for a microscope, and particularly to an illumination system for a structured light microscope. Background Art

[0002] For a structured light microscope, its working principle is to modulate an illumination light source to generate a set of modulated lights with different phases and irradiate them on a sample. Then, by calculating the images modulated by this set of modulated lights with different phases, information on the focal plane is extracted from the data to reconstruct sectional images and three-dimensional images. The generated images have higher quality than conventional microscopes and are close to confocal microscopes. Moreover, it has a simple structure and a fast imaging speed, and has great advantages in terms of cost performance.

[0003] There are mainly two types of devices for modulating the illumination light source of structured light microscopes on the market. One is a grating used as a spatial light modulator, and the other is a digital micromirror device used as a spatial light modulator. The spatial light modulator with a grating structure is relatively convenient to process, easy to make large in size, and easier to achieve large-field illumination. However, when changing the modulated images with different phases, a piezoelectric ceramic is required to drive the grating to shift. This structure is relatively unstable and prone to generating black and white stripes during the image reconstruction process. The spatial light modulator using a digital micromirror device is relatively easy to stably switch the modulated images with different phases, but it is difficult to make large in size due to processing difficulties. 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 that can stably switch the modulated images with different phases and has large-field illumination.

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

[0006] Compared with the prior art, the advantages of the present invention are as follows: by providing an aberration-corrected combined lens between the digital micromirror device and the microscope body, which can correct the position offset of the modulated image projected on the sample surface of the sample stage of the microscope body by the digital micromirror device at different wavelengths within the visible light range, and by selecting the focal length of a specific aberration-corrected lens group and a specific relationship between the focal length of the aberration-corrected lens group and the diagonal length of the digital micromirror device, while stably realizing the switching of modulated images with different phases using the digital micromirror device, the range of a single image is increased, a larger area can be imaged in a single imaging, more comprehensive spatial information can be provided, the number of movements of the sample or the lens is reduced and the efficiency is improved, the scanning speed can be increased in fast-scanning stitching applications, it is convenient to observe the overall structure of the sample and the correlation of different regions, so as to obtain more comprehensive information and clearer details, which helps to analyze and measure more precisely.

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

[0008] In another embodiment, the aberration-corrected combined lens may also be composed of the aberration-corrected lens group and an optical path extension structure disposed between the aberration-corrected 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 disposed at the front focal point position of the aberration-corrected lens group. The front focal point of the first lens group coincides with the rear focal point of the aberration-corrected 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 towards 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 part of the frame of the microscope body, an optical path extension structure is usually required for the illumination system to extend the optical path.

[0009] Preferably, the rear focal point of the first lens group and the front focal point of the second lens group coincide at a coincidence point, and the first lens group and the second lens group are symmetric about the coincidence point. The symmetric design can reduce the part cost as much as possible.

[0010] Preferably, a reflecting mirror for bending the optical path is disposed between the first lens group and the second lens group. Using a reflecting mirror to realize the bending of the optical path can avoid the situation of too long one-way optical path.

[0011] Preferably, the anastigmatic 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 towards the microscope body. The first lens, the second lens, and the third lens all have positive optical powers, and the triplet lens and the doublet lens both have negative optical powers.

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

[0013] Preferably, the first singlet lens is a meniscus lens with a convex surface facing the digital micromirror device, the second singlet lens is a biconvex lens, and the third singlet lens is a biconcave lens. Description of the Drawings

[0014] Figure 1 is a schematic structural diagram of the structured light microscope of the present invention;

[0015] Figure 2 is a partial schematic structural diagram of the illumination system and the microscope body of the structured light microscope in Example 1 of the present invention;

[0016] Figure 3 is an enlarged structural diagram of the digital micromirror device and the anastigmatic lens group in Example 1 of the present invention;

[0017] Figure 4 is a partial structural diagram of the digital micromirror device, the anastigmatic lens group, and the microscope body in Example 2 of the present invention;

[0018] Figure 5 is a structural diagram of the digital micromirror device and the anastigmatic lens group in Example 3 of the present invention;

[0019] Figure 6 is a structural diagram of the digital micromirror device and the anastigmatic lens group in Example 4 of the present invention.

[0020] Description of the Reference Numerals:

[0021] 1. Light source; 2. Digital micromirror device; 4. Aberration-corrected lens group; 41. First lens; 42. Triplet lens; L1. First singlet lens; L2. Second singlet lens; L3. Third singlet lens; 43. Doublet lens; L4. Fourth singlet lens; L5. Fifth singlet lens; 44. Second lens; 45. Third lens; 7. Optical path extension structure; 71. First lens group; 72. Second lens group; 73. Reflecting mirror; 8. Microscope body; 81. Sample stage; 82. Objective lens; 83. Beam splitter; 84. Imaging system; 85. Camera. Detailed implementation mode

[0022] The present invention will be further described in detail below in conjunction with the embodiments with reference to the drawings.

[0023] In this embodiment, the term "front" refers to the direction close to the digital micromirror device 2, and the term "rear" refers to the direction close to the microscope body 8.

[0024] Embodiment: As Figure 1 shown, an illumination system of a structured light microscope includes a light source 1 and a digital micromirror device 2 for generating different phase modulation images. An aberration-corrected combined lens is provided between the digital micromirror device 2 and the microscope body 8. The microscope body 8 includes a sample stage 81, an objective lens 82, a beam splitter 83, an imaging system 84 and a camera 85. The aberration-corrected combined lens is used to correct the position offset of the modulated image on the sample surface projected by the digital micromirror device 2 on the sample stage 81 of the microscope body 8 at different wavelengths within the visible light range. The aberration-corrected combined lens includes an aberration-corrected lens group 4. The focal length f of the aberration-corrected lens group 4 is 45 mm to 70 mm. The focal length f of the aberration-corrected lens group 4 and the diagonal length X of the digital micromirror device 2 satisfy the following relationship: X≥0.125×f.

[0025] The aberration-corrected combined lens can be a single aberration-corrected lens group 4, or an aberration-corrected lens group 4 plus an optical path extension structure 7. Figure 1 The aberration-corrected combined lens of the present embodiment shown is composed of an aberration-corrected lens group 4 and an optical path extension structure 7 provided between the aberration-corrected lens group 4 and the microscope body 8. The optical path extension structure 7 is composed of a first lens group 71 and a second lens group 72. A reflecting mirror 73 for bending the optical path is provided 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 symmetric about the coincidence point. The front focal point of the first lens group 71 coincides with the rear focal point of the aberration-corrected lens group 4. The rear focal point of the second lens group 72 coincides with the focal point in the direction of the objective lens 82 facing the digital micromirror device 2. The digital micromirror device 2 is arranged at the front focal point position of the aberration-corrected lens group 4. From Figure 1As can be seen, the light emitted from the second lens group 72 is incident on the beam splitter 83, reflected into the objective lens 82, and then irradiates the surface of the sample on the sample stage 81. The light emitted from the surface of the sample is imaged on the camera 85 through the imaging system 84.

[0026] The aberration-corrected lens group 4 is composed of a first lens 41, a cemented lens 42, a doublet lens 43, a second lens 44, and a third lens 45 arranged in sequence from the digital micromirror device 2 towards the microscope body 8. The focal powers of the first lens 41, the second lens 44, and the third lens 45 are all positive, and the focal powers of the cemented lens 42 and the doublet lens 43 are both negative. The cemented lens 42 is composed of a first singlet lens L1 with a negative focal length, a second singlet lens L2 with a positive focal length, and a third singlet lens L3 with a negative focal length arranged in sequence from the digital micromirror device 2 towards the microscope body 8. The first singlet lens L1 is a meniscus lens with a convex surface facing the digital micromirror device 2, the second singlet lens L2 is a biconvex lens, and the third singlet lens L3 is a biconcave lens. The doublet lens 43 is composed of a fourth singlet lens L4 with a negative focal length and a fifth singlet lens L5 with a positive focal length arranged in sequence from the digital micromirror device 2 towards the microscope body 8.

[0027] The following are four specific examples of the embodiments of the present invention. In each example, the value of the radius of curvature R of the spherical surface convex towards the light source 1 direction is positive, and the value of the radius of curvature R of the spherical surface convex towards the microscope body 8 direction is negative.

[0028] Example 1: As Figure 2 and Figure 3 shown, along the light propagation direction, the lens structure of the aberration-corrected lens group 4 is described by the first spherical surface to the thirteenth spherical surface. 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 as 5.7 mm, the center of the digital micromirror device 2 is placed at the front focal point position of the aberration-corrected lens group 4, and the distance from the first spherical surface is 25.1 mm. The focal length f of the aberration-corrected lens group 4 is 45 mm. The specific parameters of the aberration-corrected lens group 4 are shown in Table 1.

[0029] 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 singlet lens L1, the fourth spherical surface is the light incident surface of the second singlet lens L2, the fifth spherical surface is the light incident surface of the third singlet lens L3, the sixth spherical surface is the light exit surface of the third singlet lens L3, the seventh spherical surface is the light incident surface of the fourth singlet lens L4, the eighth spherical surface is the light incident surface of the fifth singlet lens L5, the ninth spherical surface is the light exit surface of the fifth singlet 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.

[0030] Table 1

[0031]

[0032] The anastigmatic combined lens of the first example consists of an anastigmatic lens group 4 and an optical path extension structure 7. Both the first lens group 71 and the second lens group 72 of the optical path extension structure 7 are lenses with a cemented doublet structure, and the lens thickness is 6 mm. Among them, the distance from the front focal point 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 rear focal point of the first lens group 71 to the center of the rear surface of the first lens group 71 is 177.4 mm, the distance from the front focal point of the second lens group 72 to the center of the front surface of the second lens group 72 is 177.4 mm, the distance from the rear focal point of the second lens group 72 to the center of the rear surface of the second lens group 72 is 178.8 mm, and the optical path of the entire illumination system is extended by 724.4 mm. After the light passes through the optical path extension structure 7, it enters the objective lens 82 and then irradiates on the surface of the sample on the sample stage 81. The light emitted from the surface of the sample is imaged on the camera 85 through the imaging system 84, and illumination within a field of view range of 25.3 mm can be achieved.

[0033] Example 2: As Figure 4 shown, along the light propagation direction, the lens structures of the anastigmatic lens group 4 are described from the first spherical surface to the thirteenth spherical surface. The first spherical surface is close to the digital micromirror device 2, and the thirteenth spherical surface is close to the microscope main 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 focal point position of the anastigmatic lens group 4, where the distance from the first spherical surface is 29.6 mm. The focal length f of the anastigmatic lens group 4 is 50 mm, and the specific parameters of the anastigmatic lens group 4 are shown in Table 2.

[0034] 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 singlet lens L1, the fourth spherical surface is the light incident surface of the second singlet lens L2, the fifth spherical surface is the light incident surface of the third singlet lens L3, the sixth spherical surface is the light exit surface of the third singlet lens L3, the seventh spherical surface is the light incident surface of the fourth singlet lens L4, the eighth spherical surface is the light incident surface of the fifth singlet lens L5, the ninth spherical surface is the light exit surface of the fifth singlet 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.

[0035] Table 2

[0036]

[0037] The aberration-corrected combined lens in this second example is a single aberration-corrected lens group 4 without using an optical path extension structure. Light enters the objective lens 82 and irradiates the surface of the sample 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 field of view range of 24.8 mm can be achieved.

[0038] Example 3: As Figure 5 shown, along the light propagation direction, the lens structure of the aberration-corrected lens group 4 is described from the first spherical surface to the thirteenth spherical surface. The first spherical surface is close to the digital micromirror device 2, and the thirteenth spherical surface is close to the microscope main 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 focal position of the aberration-corrected lens group 4, and the distance from the first spherical surface is 40.4 mm. The focal length f of the aberration-corrected lens group 4 is 60 mm. The specific parameters of the aberration-corrected lens group 4 are shown in Table 3.

[0039] 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 singlet lens L1, the fourth spherical surface is the light incident surface of the second singlet lens L2, the fifth spherical surface is the light incident surface of the third singlet lens L3, the sixth spherical surface is the light exit surface of the third singlet lens L3, the seventh spherical surface is the light incident surface of the fourth singlet lens L4, the eighth spherical surface is the light incident surface of the fifth singlet lens L5, the ninth spherical surface is the light exit surface of the fifth singlet 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.

[0040] Table 3

[0041]

[0042] This Example 3 only includes the digital micromirror device 2 and the aberration-corrected lens group 4. At the rear, it can be directly connected to the microscope main body 8 if space permits, or an optical path extension structure 7 can be connected. Light enters the objective lens 82 and irradiates the surface of the sample 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 field of view range of 25.0 mm can be achieved.

[0043] Example 4: As Figure 6As shown in the figure, along the light propagation direction, the first spherical surface to the thirteenth spherical surface describe the lens structure of the anastigmatic 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 9.0 mm. The center of the digital micromirror device 2 is placed at the front focal point position of the anastigmatic lens group 4, and the distance from the first spherical surface is 55.2 mm. The focal length f of the anastigmatic lens group 4 is 70 mm. The specific parameters of the anastigmatic lens group 4 are shown in Table 4.

[0044] 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 singlet lens L1, the fourth spherical surface is the light incident surface of the second singlet lens L2, the fifth spherical surface is the light incident surface of the third singlet lens L3, the sixth spherical surface is the light exit surface of the third singlet lens L3, the seventh spherical surface is the light incident surface of the fourth singlet lens L4, the eighth spherical surface is the light incident surface of the fifth singlet lens L5, the ninth spherical surface is the light exit surface of the fifth singlet 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.

[0045] Table 4

[0046]

[0047] In this Example 4, there are only the digital micromirror device 2 and the anastigmatic lens group 4. At the rear part, it can be directly connected to the microscope body 8 if space permits, or an optical path extension structure 7 can be connected. The light enters the objective lens 82 and irradiates on 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 field of view range of 25.7 mm can be achieved.

Claims

1. An illumination system for a structured light microscope, comprising a light source and a digital micromirror device for generating images with different phase modulations, characterized in that, An anastigmatic combination lens is provided between the digital micromirror device and the microscope body. The digital micromirror device is disposed at the front focal position of the anastigmatic combination lens. The rear focal point of the anastigmatic combination lens coincides with the focal point of the objective lens of the microscope body in the direction towards the digital micromirror device. The anastigmatic combination lens is used to correct the position offset of the modulated image projected by the digital micromirror device onto the sample surface of the sample stage of the microscope body at different wavelengths within the visible light range. The anastigmatic combination lens includes an anastigmatic lens group, and the focal length f of the anastigmatic lens group is 45 mm to 70 mm. The focal length f of the anastigmatic lens group and the diagonal length X of the digital micromirror device satisfy the following relationship: X ≥ 0.125 × f.

2. The illumination system of a structured light microscope according to claim 1, characterized in that, The anastigmatic combination lens is a single anastigmatic lens group. The digital micromirror device is disposed at the front focal position of the anastigmatic lens group. The rear focal point of the anastigmatic lens group coincides with the focal point of the objective lens of the microscope body in the direction towards the digital micromirror device.

3. The illumination system of a structured light microscope according to claim 1, characterized in that, The anastigmatic combination lens is composed of the anastigmatic lens group and an optical path extension structure disposed between the anastigmatic 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 disposed at the front focal position of the anastigmatic lens group. The front focal point of the first lens group coincides with the rear focal point of the anastigmatic lens group. 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 towards the digital micromirror device.

4. The illumination system of a structured light microscope according to claim 3, characterized in that, The rear focal point of the first lens group and the front focal point of the second lens group coincide at a coincidence point, and the first lens group and the second lens group are symmetric about the coincidence point.

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

6. The illumination system of a structured light microscope according to any one of claims 1 to 5, characterized in that, The anastigmatic lens group is composed of a first lens, a triple cemented lens, a double cemented lens, a second lens, and a third lens arranged in sequence from the digital micromirror device towards the microscope body. The first lens, the second lens, and the third lens all have positive optical powers, and the triple cemented lens and the double cemented lens both have negative optical powers.

7. The illumination system of a structured light microscope according to claim 6, wherein, The triple cemented lens is composed of a first singlet lens with a negative focal length, a second singlet lens with a positive focal length, and a third singlet lens with a negative focal length arranged in sequence from the digital micromirror device towards the microscope body. The double cemented lens is composed of a fourth singlet lens with a negative focal length and a fifth singlet lens with a positive focal length arranged in sequence from the digital micromirror device towards the microscope body.

8. The illumination system of a structured light microscope according to claim 7, characterized in that, The first singlet lens is a meniscus lens with a convex surface facing the digital micromirror device. The second singlet lens is a biconvex lens. The third singlet lens is a biconcave lens.

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