Wide-band complex-achromatic low-light-level flat-field telecentric microscope objective optical system

Abstract

The application discloses a wide-band complex-achromatic faint light flat-field telecentric microscopic objective optical system, which comprises lens groups G1, G2 and G3 arranged in sequence along the light path propagation direction; the lens group G1 comprises lenses L1, L2 and L3 arranged in sequence along the light path propagation direction; the light power of the lens L1 is positive, the light power of the lens L2 is negative, and the light power of the lens L3 is negative; the lens group G2 comprises lenses L4, L5 and L6 arranged in sequence along the light path propagation direction; the light power of the lens L4 is negative, the light power of the lens L5 is positive, and the light power of the lens L6 is negative; the lens group G3 comprises lenses L7 and L8 arranged in sequence along the light path propagation direction; the light power of the lens L7 is positive, and the light power of the lens L8 is negative. The wide-band complex-achromatic faint light flat-field telecentric microscopic objective optical system has the characteristics of good imaging quality, wide band, long object distance and high telecentricity, and the applicable band is 0.4 um to 1.7 um.

Description

Technical Field

[0001] This invention relates to a wide-band apochromatic micro-plan telecentric microscope objective optical system, belonging to the field of microscope objective technology. Background Technology

[0002] With the maturation of visible light microscopy, the market now requires wide-range microscopic imaging (400nm-1700nm) for dynamic spectral tracking and static spectral analysis to meet the needs of high-end material detection. These objectives are mainly suitable for microcircuit board inspection in the 3C industry, as well as for pharmaceuticals and food. They can quickly distinguish and identify different impurities or abnormal products, enabling screening of previously calibrated patterns. They can also penetrate and inspect packaged products made of synthetic fibers and nylon. Furthermore, they are widely used in life sciences for pathological diagnosis. However, current microscope objectives have a relatively narrow operating wavelength. For example, patent application number 201710113001.0 discloses a microscope objective and a wide-field, high-resolution imaging system with a first lens group, second lens group, third lens group, fourth lens group, fifth lens group, sixth lens group, seventh lens group, eighth lens group, ninth lens group, and tenth lens group arranged sequentially from left to right. However, this system can only image in the 460-650nm wavelength range. There are currently no suitable wide-band microscope objectives for 400-1700nm.

[0003] Against this background, the present invention provides a wide-band apochromatic micro-plan telecentric microscope objective optical system with a focal length of 200mm, a magnification of 1x, and an applicable wavelength range of 0.4um to 1.7um. It features a wide applicable wavelength range, high telecentricity, and long object distance, and is suitable for applications such as microcircuit board inspection, pharmaceutical and food inspection, medical imaging inspection, and spectral analysis. Summary of the Invention

[0004] This invention provides an optical system for a 1X wideband apochromatic telecentric microscope objective, suitable for the visible to near-infrared range, which is used with a 200mm tube lens. It features good imaging quality, wide band, long object distance, and high telecentricity.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A wideband apochromatic micro-plan telecentric microscope objective optical system includes lens group G1, lens group G2 and lens group G3 arranged sequentially along the optical path propagation direction.

[0007] The optical power of lens group G1 is positive, the optical power of lens group G2 is negative, and the optical power of lens group G3 is positive.

[0008] Lens group G1 includes lenses L1, L2 and L3 arranged sequentially along the optical path propagation direction; lens L1 has positive optical power, lens L2 has negative optical power, and lens L1 and lens L2 are combined to form a cemented lens; lens L3 has negative optical power.

[0009] Lens group G2 includes lenses L4, L5 and L6 arranged sequentially along the optical path propagation direction; lens L4 has a negative optical power, lens L5 has a positive optical power, and lens L4 and lens L5 are combined to form a cemented lens; lens L6 has a negative optical power.

[0010] Lens group G3 includes lens L7 and lens L8 arranged sequentially along the optical path propagation direction; lens L7 has a positive optical power and lens L8 has a negative optical power, and lens L7 and lens L8 are combined to form a cemented lens.

[0011] The applicable wavelength range for the wideband apochromatic micro-plan telecentric microscope objective optical system is 0.4µm to 1.7µm.

[0012] This optical system is an infinite tube microscope objective system.

[0013] The optical powers of the lens groups G1, G2, and G3 mentioned above are positive and negative positive, respectively, and they are symmetrical.

[0014] The aforementioned microscope objective optical system achieves wide-band imaging from 0.4µm to 1.7µm.

[0015] The aforementioned broadband apochromatic low-light plan telecentric microscope objective optical system simultaneously satisfies the following relationships: 0.3F < FG1 < 0.4F, -0.2F < FG2 < -0.05F, 0.1F < FG3 < 0.3F, where F is the system focal length of the broadband apochromatic low-light plan telecentric microscope objective optical system, FG1 is the focal length of lens group G1, FG2 is the focal length of lens group G2, and FG3 is the focal length of lens group G3.

[0016] To further improve imaging quality, the aforementioned wideband apochromatic low-light-plan telecentric microscope objective optical system simultaneously satisfies the following relationships: 0.1F < f1 < 0.2F, -0.6F < f2 < -0.5F, -0.2F < f3 < -0.1F, where F is the system focal length of the wideband apochromatic low-light-plan telecentric microscope objective optical system, f1 is the focal length of lens L1, f2 is the focal length of lens L2, and f3 is the focal length of lens L3.

[0017] To further improve imaging quality, the aforementioned wideband apochromatic low-light-plan telecentric microscope objective optical system simultaneously satisfies the following relationships: -0.1F < f4 < -0.02F, 0.02F < f5 < 0.04F, -0.1F < f6 < -0.06F, 0.1F < f7 < 0.3F, -0.6F < f8 < -0.4F, where F is the system focal length of the wideband apochromatic low-light-plan telecentric microscope objective optical system, f4 is the focal length of lens L4, f5 is the focal length of lens L5, f6 is the focal length of lens L6, f7 is the focal length of lens L7, and f8 is the focal length of lens L8.

[0018] The above-mentioned lens L1 is a biconvex spherical lens with positive optical power; lens L2 is a meniscus spherical lens with negative optical power; lens L3 is a meniscus spherical lens with negative optical power; the center thickness of lens L1 is 4.13±0.03mm, the center thickness of lens L2 is 1.50±0.03mm, and the center thickness of lens L3 is 1.30±0.03mm.

[0019] To better ensure imaging performance, along the optical path propagation direction, lens L1 has two surfaces that are, in sequence, the first object-side surface and the first image-side surface; lens L2 has two surfaces that are, in sequence, the second object-side surface and the second image-side surface; and lens L3 has two surfaces that are, in sequence, the third object-side surface and the third image-side surface. The radius of curvature of the first object-side surface is 14.223±0.005mm, and the radius of curvature of the first image-side surface is -25.390±0.005mm; the radius of curvature of the second object-side surface is -25.390±0.005mm, and the radius of curvature of the second image-side surface is -39.379±0.005mm; the radius of curvature of the third object-side surface is -15.280±0.005mm, and the radius of curvature of the third image-side surface is -38.242±0.005mm.

[0020] The above-mentioned lens L4 is a biconcave spherical lens with negative optical power; lens L5 is a biconvex spherical lens with positive optical power; lens L6 is a plano-concave spherical lens with negative optical power; the center thickness of lens L4 is 1.30±0.03mm, the center thickness of lens L5 is 4.29±0.03mm, and the center thickness of lens L6 is 1.30±0.03mm.

[0021] To better ensure imaging performance, along the light propagation direction, lens L4 has two surfaces that are the fourth object-side surface and the fourth image-side surface, lens L5 has two surfaces that are the fifth object-side surface and the fifth image-side surface, and lens L6 has two surfaces that are the sixth object-side surface and the sixth image-side surface. The radius of curvature of the fourth object-side surface is -24.156±0.005mm, the radius of curvature of the fourth image-side surface is 7.700±0.005mm, the radius of curvature of the fifth object-side surface is 7.700±0.005mm, the radius of curvature of the fifth image-side surface is -17.906±0.005mm, the radius of curvature of the sixth object-side surface is -11.373±0.005mm, and the radius of curvature of the sixth image-side surface is infinite.

[0022] Lens L7 is a biconvex spherical lens with positive optical power; lens L8 is a meniscus spherical lens with negative optical power; the center thickness of lens L7 is 6.64±0.03mm, and the center thickness of lens L8 is 1.80±0.03mm; along the direction of light propagation, the two sides of lens L7 are the seventh object-side and the seventh image-side, respectively, and the two sides of lens L8 are the eighth object-side and the eighth image-side, respectively; the radius of curvature of the seventh object-side is 245.500±0.005mm, the radius of curvature of the seventh image-side is -19.440±0.005mm; the radius of curvature of the eighth object-side is -19.440±0.005mm, and the radius of curvature of the eighth image-side is -26.490±0.005mm.

[0023] To better balance the overall performance of the optical system, the center spacing between lenses L1 and L2 is 0 mm; the center spacing between lenses L2 and L3 is 7.98 ± 0.03 mm; the center spacing between lenses L3 and L4 is 23.67 ± 0.03 mm; the center spacing between lenses L4 and L5 is 0 mm; the center spacing between lenses L5 and L6 is 17.58 ± 0.03 mm; the center spacing between lenses L6 and L7 is 18.61 ± 0.03 mm; and the center spacing between lenses L7 and L8 is 0 mm.

[0024] Any techniques not mentioned in this invention are based on existing technologies.

[0025] The broadband apochromatic micro-plan telecentric microscope objective optical system of this invention has the following beneficial effects:

[0026] 1) The optical system described in this invention achieves wide-band achromatic aberration of 0.4µm to 1.7µm, applicable to a long wavelength range.

[0027] 2) The optical system described in this invention has a large object distance of 18mm, a large space between the object surface and the lens, and a wide range of applications.

[0028] 3) The optical system described in this invention adopts an object-side telecentric design with a telecentricity of <0.7°. It has high telecentricity, stable magnification, and is suitable for optical measurement. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the optical principle system of the present invention;

[0030] Figure 2 This is a schematic diagram of the structure of the optical system according to a detailed embodiment of the present invention;

[0031] Figure 3 This is a transfer function curve of the optical system of the present invention;

[0032] Figure 4 This is a diagram showing the axial chromatic aberration of the optical system of the present invention.

[0033] Figure 5 This is a diagram showing the chromatic aberration curve of the optical system of the present invention.

[0034] Figure 6 This is a full-field distortion curve of the optical system of the present invention; Detailed Implementation

[0035] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0036] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following description is provided in conjunction with the appendix. Figure 1-6 Please provide a detailed explanation.

[0037] like Figure 1-2 As shown, a broadband apochromatic micro-plan telecentric microscope objective optical system is an infinite tube microscope objective system, such as... Figure 1 As shown, from infinite space to the object surface, it consists of lens group G1, lens group G2 and lens group G3 arranged sequentially along the direction of light propagation.

[0038] Lens group G1 has positive optical power and consists of lenses L1, L2 and L3 arranged sequentially along the direction of light propagation. Lens L1 and L2 are combined to form a cemented lens. Lens L1 is a biconvex spherical lens with positive optical power, lens L2 is a meniscus spherical lens with negative optical power, and lens L3 is a meniscus spherical lens with negative optical power. The system aperture is located on the outer surface of lens L1.

[0039] Lens group G2 has negative optical power and consists of lenses L4, L5 and L6 arranged sequentially along the direction of light propagation. Lens L4 and L5 are combined to form a cemented lens. Lens L4 is a biconcave spherical lens with negative optical power, lens L5 is a biconvex spherical lens with positive optical power, and lens L6 is a planoconcave spherical lens with negative optical power.

[0040] Lens group G3 has positive optical power and consists of lenses L7 and L8 arranged sequentially along the direction of light propagation. Lens L7 and L8 are combined to form a cemented lens. Lens L7 is a biconvex spherical lens with positive optical power, and lens L8 is a meniscus spherical lens with negative optical power.

[0041] Let the system focal length of the wideband apochromatic micro-plan telecentric microscope objective system be F, the focal length of group G1 be FG1, the focal length of group G2 be FG2, the focal length of group G1 be FG3, and the focal lengths of the first to eighth lenses be f1, f2, f3, f4, f5, f6, f7, and f8, respectively.

[0042] Among them, 0.3F < FG1 < 0.4F, -0.2F < FG2 < -0.05F, and 0.1F < FG3 < 0.3F;

[0043] Each lens has the following characteristics:

[0044] Lens L1 is a biconvex spherical lens with positive optical power, 0.1F < f1 < 0.2F;

[0045] Lens L2 is a meniscus spherical lens with negative optical power, -0.6F < f2 < -0.5F;

[0046] Lens L3 is a meniscus spherical lens with negative optical power, -0.2F < f3 < -0.1F;

[0047] Lens L4 is a biconcave spherical lens with negative optical power, -0.1F < f4 < -0.02F;

[0048] Lens L5 is a biconvex spherical lens with positive optical power, 0.02F < f5 < 0.04F;

[0049] Lens L6 is a plano-concave spherical lens with negative optical power, -0.1F < f6 < -0.06F;

[0050] Lens L7 is a biconvex spherical lens with positive optical power, 0.1F < f7 < 0.3F;

[0051] Lens L8 is a meniscus spherical lens with negative optical power, -0.6F < f8 < -0.4F;

[0052] Table 1 shows the technical specifications of the optical system described in this embodiment, and Table 2 shows the specific optical parameters of the optical system described in this embodiment.

[0053] Table 1 Technical Specifications of the Wideband Apochromatic Low-Light Plan Telecentric Microscope Objective System

[0054]

[0055] Table 2. Specific optical parameters of the broadband apochromatic low-light plan telecentric microscope objective optical system.

[0056]

[0057]

[0058] In Table 2, radius of curvature refers to the radius of curvature of each lens surface, thickness or spacing refers to the lens thickness or the distance between adjacent lens surfaces, material refers to the material used in the lens, and air refers to the medium between two lenses being air. Along the direction of light propagation, the two sides of lens L1 are, in order, the first object-side surface S1 and the first image-side surface S2; the two sides of lens L2 are, in order, the second object-side surface S2 (with the same radius of curvature as the first image-side surface and cemented together) and the second image-side surface S3; the two sides of lens L3 are, in order, the third object-side surface S4 and the third image-side surface S5; the two sides of lens L4 are, in order, the fourth object-side surface S6 and the fourth image-side surface S7; the two sides of lens L5 are, in order, the fifth object-side surface S7 (with the same radius of curvature as the fourth image-side surface and cemented together) and the fifth image-side surface S8; the two sides of lens L6 are, in order, the sixth object-side surface S9 and the sixth image-side surface S10; the two sides of lens L7 are, in order, the seventh object-side surface S11 and the seventh image-side surface S12; and the two sides of lens L8 are, in order, the eighth object-side surface S12 (with the same radius of curvature as the seventh image-side surface and cemented together) and the eighth image-side surface S1.

[0059] Figure 3 The transfer function curve of the above-mentioned wide-band apochromatic micro-light plan telecentric microscope objective optical system is shown. The full-field transfer function value is close to the diffraction limit, and the image quality is excellent. Figure 4 This is a graph showing the axial chromatic aberration of the aforementioned broadband apochromatic micro-plan telecentric microscope objective optical system. Figure 5 The transverse chromatic aberration curve of the aforementioned broadband apochromatic micro-plan telecentric microscope objective optical system is shown below. Figure 4 , 5 It can be seen that this invention achieves a wide-band apochromatic design of 0.4um-1.7um. From Figure 6 It can be seen that the distortion across the entire field of view is less than 0.2%.

Claims

1. A broadband apochromatic low-light plan telecentric microscope objective optical system, characterized in that: It includes lens group G1, lens group G2 and lens group G3 arranged sequentially along the direction of light propagation; The optical power of lens group G1 is positive, the optical power of lens group G2 is negative, and the optical power of lens group G3 is positive. Lens group G1 includes lenses L1, L2 and L3 arranged sequentially along the optical path propagation direction; lens L1 has a positive optical power, lens L2 has a negative optical power, and lens L1 and lens L2 are combined to form a cemented lens; lens L3 has a negative optical power. Lens group G2 includes lenses L4, L5 and L6 arranged sequentially along the optical path propagation direction; lens L4 has a negative optical power, lens L5 has a positive optical power, and lens L4 and lens L5 are combined to form a cemented lens; lens L6 has a negative optical power. Lens group G3 includes lens L7 and lens L8 arranged sequentially along the optical path propagation direction; lens L7 has a positive optical power and lens L8 has a negative optical power, and lens L7 and lens L8 are combined to form a cemented lens. The applicable wavelength range for the wideband apochromatic micro-plan telecentric microscope objective optical system is 0.4µm to 1.7µm.

2. The broadband apochromatic micro-plan telecentric microscope objective optical system as described in claim 1, characterized in that: Simultaneously satisfying the following relationships: 0.3F < FG1 < 0.4F, -0.2F < FG2 < -0.05F, 0.1F < FG3 < 0.3F, where F is the system focal length of the broadband apochromatic micro-plan telecentric microscope objective optical system, FG1 is the focal length of lens group G1, FG2 is the focal length of lens group G2, and FG3 is the focal length of lens group G3.

3. The broadband apochromatic micro-plan telecentric microscope objective optical system as described in claim 1 or 2, characterized in that: Simultaneously satisfying the following relationships: 0.1F < f1 < 0.2F, -0.6F < f2 < -0.5F, -0.2F < f3 < -0.1F, Wherein, F is the system focal length of the wideband apochromatic micro-planar telecentric microscope objective optical system, f1 is the focal length of lens L1, f2 is the focal length of lens L2, and f3 is the focal length of lens L3.

4. The broadband apochromatic micro-plan telecentric microscope objective optical system as described in claim 1 or 2, characterized in that: Simultaneously satisfying the following relationships: -0.1F < f4 < -0.02F, 0.02F < f5 < 0.04F, -0.1F < f6 < -0.06F, 0.1F < f7 < 0.3F, -0.6F < f8 < -0.4F, where F is the system focal length of the broadband apochromatic micro-plan telecentric microscope objective optical system, f4 is the focal length of lens L4, f5 is the focal length of lens L5, f6 is the focal length of lens L6, f7 is the focal length of lens L7, and f8 is the focal length of lens L8.

5. The broadband apochromatic micro-plan telecentric microscope objective optical system as described in claim 1 or 2, characterized in that: Lens L1 is a biconvex spherical lens with positive optical power; lens L2 is a meniscus spherical lens with negative optical power; lens L3 is a meniscus spherical lens with negative optical power; the center thickness of lens L1 is 4.13±0.03mm, the center thickness of lens L2 is 1.50±0.03mm, and the center thickness of lens L3 is 1.30±0.03mm.

6. The broadband apochromatic micro-plan telecentric microscope objective optical system as described in claim 1 or 2, characterized in that: Along the direction of light propagation, the two sides of lens L1 are the first object-side surface and the first image-side surface, the two sides of lens L2 are the second object-side surface and the second image-side surface, and the two sides of lens L3 are the third object-side surface and the third image-side surface, respectively. The radius of curvature of the first object-side surface is 14.223±0.005mm, and the radius of curvature of the first image-side surface is -25.390±0.005mm; the radius of curvature of the second object-side surface is -25.390±0.005mm, and the radius of curvature of the second image-side surface is -39.379±0.005mm; the radius of curvature of the third object-side surface is -15.280±0.005mm, and the radius of curvature of the third image-side surface is -38.242±0.005mm.

7. The broadband apochromatic micro-plan telecentric microscope objective optical system as described in claim 1 or 2, characterized in that: Lens L4 is a biconcave spherical lens with negative optical power; lens L5 is a biconvex spherical lens with positive optical power; lens L6 is a plano-concave spherical lens with negative optical power; the center thickness of lens L4 is 1.30±0.03mm, the center thickness of lens L5 is 4.29±0.03mm, and the center thickness of lens L6 is 1.30±0.03mm.

8. The broadband apochromatic micro-plan telecentric microscope objective optical system as described in claim 1 or 2, characterized in that: Along the direction of light propagation, the two sides of lens L4 are the fourth object side and the fourth image side, respectively; the two sides of lens L5 are the fifth object side and the fifth image side, respectively; and the two sides of lens L6 are the sixth object side and the sixth image side, respectively. The radius of curvature of the fourth object's lateral surface is -24.156±0.005mm, and the radius of curvature of the fourth image's lateral surface is 7.700±0.005mm; the radius of curvature of the fifth object's lateral surface is 7.700±0.005mm, and the radius of curvature of the fifth image's lateral surface is -17.906±0.005mm; the radius of curvature of the sixth object's lateral surface is -11.373±0.005mm, and the radius of curvature of the sixth image's lateral surface is infinite.

9. The broadband apochromatic micro-plan telecentric microscope objective optical system as described in claim 1 or 2, characterized in that: Lens L7 is a biconvex spherical lens with positive optical power; lens L8 is a meniscus spherical lens with negative optical power; the center thickness of lens L7 is 6.64±0.03mm, and the center thickness of lens L8 is 1.80±0.03mm. Along the direction of light propagation, the two sides of lens L7 are the seventh object-side and the seventh image-side, respectively, and the two sides of lens L8 are the eighth object-side and the eighth image-side, respectively. The radius of curvature of the seventh object-side is 245.500±0.005mm, the radius of curvature of the seventh image-side is -19.440±0.005mm, the radius of curvature of the eighth object-side is -19.440±0.005mm, and the radius of curvature of the eighth image-side is -26.490±0.005mm.

10. The broadband apochromatic micro-plan telecentric microscope objective optical system as described in claim 1 or 2, characterized in that: The center spacing between lenses L1 and L2 is 0 mm; the center spacing between lenses L2 and L3 is 7.98 ± 0.03 mm; the center spacing between lenses L3 and L4 is 23.67 ± 0.03 mm; the center spacing between lenses L4 and L5 is 0 mm; the center spacing between lenses L5 and L6 is 17.58 ± 0.03 mm; the center spacing between lenses L6 and L7 is 18.61 ± 0.03 mm; and the center spacing between lenses L7 and L8 is 0 mm.

Images