A fixed-focus wide-spectrum objective applied to a large target surface detector

Abstract

The utility model discloses a kind of fixed focus wide-spectrum objectives applied to large target detector, including objective body, the objective body adopts ten-piece lens combination, fixed arrangement on same optical axis, first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens, ninth lens, tenth lens, detector are sequentially arranged from object image side to detector side along optical axis.The utility model features are: ten-piece lens combination is used, positive and negative optical power distribution reduces the incidence angle of off-axis beam and chief ray on each lens surface, reduces coma, astigmatism and other optical aberration influence, clear real image can be presented on detector;Adhesive lens adopts heavy crown glass and heavy flint glass combination, which constitutes achromatic lens, compact structure, convenient to carry;Lens all adopt standard spherical lens for easy processing, which reduces manufacturing cost under the condition of mass production, improves the consistency of product performance.

Description

Technical Field

[0001] This utility model relates to the field of optical imaging technology, specifically to a fixed-focus broadband objective lens for use in large-target detectors. Background Technology

[0002] Existing fixed-focus lenses are typically only suitable for visible light detectors, resulting in poor imaging performance in low-light conditions, especially at dusk. Furthermore, 100mm focal length lenses usually have an F-number of 3.5 or higher, leading to limited light intake. They are also mostly designed to fit only 1 / 1.5-inch target surfaces, resulting in a small field of view and difficulty in meeting the flat image field requirements of large target surfaces, leading to insufficient field curvature control.

[0003] Traditional lenses are generally only optimized for the visible light spectrum range (486-656 nm), resulting in poor imaging performance in the evening (600-900 nm) conditions.

[0004] At the same time, the light intensity is lower at night, and with a higher F number, the detector receives even less light, resulting in lower image contrast. Utility Model Content

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a fixed-focus broadband objective lens for large target detectors. Its working spectral range is 460-900 nm, which improves the imaging effect of the lens in the evening. The lens has an F-number of 1.4, which allows it to receive higher light intensity and increases the contrast of the evening imaging. Considering that the larger the target surface, the larger the field of view, a 1-inch detector is selected for the design. The maximum imaging diameter of the lens can reach 16 mm, enabling the system to achieve clear imaging at a large angle both during the day and at night.

[0006] The technical solution adopted by this utility model to achieve the above objectives is as follows: A fixed-focus broadband objective lens for use in large-area detectors includes an objective lens body. The objective lens body is composed of a ten-lens assembly, fixedly arranged on the same optical axis. Along the optical axis from the image side to the detector side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and a detector are arranged sequentially. The first lens, the second lens, and the seventh lens are meniscus lenses with their convex surfaces facing the object side. The third lens, the sixth lens, the eighth lens, and the ninth lens are biconvex lenses, and the fourth lens, the fifth lens, and the tenth lens are biconcave lenses.

[0007] The focal lengths of each lens along the optical axis from the image side to the display screen side are as follows: 200 mm ≤ focal length of the first lens ≤ 300 mm, 200 mm ≤ focal length of the second lens ≤ 300 mm, 50 mm ≤ focal length of the third lens ≤ 100 mm, -100 mm ≤ focal length of the fourth lens ≤ -50 mm, -50 mm ≤ focal length of the fifth lens ≤ -21 mm, 20 mm ≤ focal length of the sixth lens ≤ 50 mm, 50 mm ≤ focal length of the seventh lens ≤ 100 mm, -100 mm ≤ focal length of the eighth lens ≤ -50 mm, 50 mm ≤ focal length of the ninth lens ≤ 100 mm, and -50 mm ≤ focal length of the tenth lens ≤ -20 mm.

[0008] All ten lenses in the objective lens body are spherical lenses.

[0009] The third lens is cemented with the fourth lens, the fifth lens is cemented with the sixth lens, and the seventh lens is cemented with the eighth lens.

[0010] The cemented lens uses a combination of crown glass and heavy flint glass.

[0011] The objective lens has an optical length of 150 mm, a field of view of 10°, an F number of 1.4, a focal length of 93 mm, and a working spectral range of 460-900 nm.

[0012] The objective lens body is suitable for a 1-inch detector with dimensions of 13.14 mm × 8.76 mm, and can be adapted to detectors with a maximum diameter of 8 mm.

[0013] The objective lens body has a central field-of-view optical transfer function greater than 0.5 and an edge field-of-view optical transfer function greater than 0.3 at a spatial frequency of 0~100 lp / mm.

[0014] The RMS spot radius of the objective lens body is 5 μm in the main field of view and 6 μm in the peripheral field of view.

[0015] The maximum distortion of the objective lens body is 0.02%.

[0016] The features of this invention are: the use of a ten-lens combination and positive and negative optical power distribution reduces the incident angle of off-axis beams and principal rays on the surfaces of each lens, reducing the influence of optical aberrations such as coma and astigmatism, enabling it to present a clear real image on the detector; the cemented lens uses a combination of crown glass and heavy flint glass to form an achromatic lens, which is compact and easy to carry; all lenses are made of standard spherical lenses that are easy to process, which reduces manufacturing costs and improves the consistency of product performance in mass production. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the optical structure of the fixed-focus broadband objective lens of this invention, which is applied to a large target detector. Figure 2 The optical transfer function curve of the fixed-focus broadband objective lens of this invention, applied to a large target detector; Figure 3 This is an optical dot diagram of the fixed-focus broadband objective lens of this invention, applied to a large target detector; Figure 4 This is a field curvature distortion diagram of the fixed-focus broadband objective lens of this invention, applied to a large target detector.

[0018] Among them: 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens; 7. Seventh lens; 8. Eighth lens; 9. Ninth lens; 10. Tenth lens; 11. Detector. Detailed Implementation

[0019] like Figure 1As shown, this utility model is a fixed-focus broadband objective lens for a large-target detector, comprising an objective lens body with a total optical length of 150mm, a field of view of 10°, an F-number of 1.4, a focal length of 93mm, and a working spectral range of 460-900 nm. It is suitable for a 1-inch detector 11, which has dimensions of 13.14 mm × 8.76 mm, and can accommodate detectors with a maximum diameter of 8mm. Specifically, the objective lens body employs a ten-lens assembly, fixedly arranged on the same optical axis. Along the optical axis from the image side to the detector side, the following lenses are arranged sequentially: first lens 1, second lens 2, third lens 3, fourth lens 4, fifth lens 5, sixth lens 6, seventh lens 7, eighth lens 8, ninth lens 9, tenth lens 10, and detector 11. Preferably, the focal lengths of each lens along the optical axis from the image side to the display screen side are: 200 mm ≤ first lens focal length ≤ 300mm, 200 mm ≤ second lens focal length ≤ 300mm, 50 mm ≤ first lens focal length ≤ 300mm, 50 mm ≤ second lens focal length ≤ 300mm, 50 mm ≤ third ... -100 mm ≤ third lens focal length ≤ 100 mm, -100 mm ≤ fourth lens focal length ≤ -50 mm, -50 mm ≤ fifth lens focal length ≤ -21 mm, 20 mm ≤ sixth lens focal length ≤ 50 mm, 50 mm ≤ seventh lens focal length ≤ 100 mm, -100 mm ≤ eighth lens focal length ≤ -50 mm, 50 mm ≤ ninth lens focal length ≤ 100 mm, -50 mm ≤ tenth lens focal length ≤ -20 mm mm; the first lens 1, the second lens 2, and the seventh lens 7 are meniscus lenses with their convex surfaces facing the object side; the third lens 3, the sixth lens 6, the eighth lens 8, and the ninth lens 9 are biconvex lenses; the fourth lens 4, the fifth lens 5, and the tenth lens 10 are biconcave lenses; the third lens 3 and the fourth lens 4 are cemented together; the fifth lens 5 and the sixth lens 6 are cemented together; the seventh lens 7 and the eighth lens 8 are cemented together; the cemented lenses are made of a combination of crown glass and heavy flint glass, forming an achromatic lens, making the structure compact and easy to carry; by using a combination of ten lenses and the distribution of positive and negative optical power, the incident angle of off-axis beams and principal rays on the surfaces of each lens is reduced, reducing the influence of optical aberrations such as coma and astigmatism, so that it can present a clear real image on the detector; all ten lenses of the objective lens body are spherical lenses, which reduces manufacturing costs and improves the consistency of product performance in mass production.

[0020] like Figure 2 As shown, this invention exhibits excellent imaging quality with a central field-of-view optical transfer function greater than 0.5 and an edge field-of-view optical transfer function greater than 0.3 at spatial frequencies of 0~100 lp / mm.

[0021] like Figure 3 As shown, the RMS spot radius of the objective lens body is 5 μm in the main field of view and 6 μm in the peripheral field of view.

[0022] like Figure 4 As shown, the maximum distortion of this invention is 0.02%, which is almost no distortion.

[0023] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model shall still fall within the scope of the present utility model's technical solution.

Claims

1. A fixed-focus broadband objective lens for use in large-target detectors, characterized in that: Includes an objective lens body, which is a ten-lens assembly, fixedly arranged on the same optical axis, with the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens, ninth lens, tenth lens, and detector arranged sequentially along the optical axis from the image side to the detector side; The first, second, and seventh lenses are meniscus lenses with their convex surfaces facing the object side; the third, sixth, eighth, and ninth lenses are biconvex lenses; and the fourth, fifth, and tenth lenses are biconcave lenses.

2. The fixed-focus broadband objective lens for a large target detector according to claim 1, characterized in that: The focal lengths of each lens along the optical axis from the image side to the display screen side are as follows: 200 mm ≤ focal length of the first lens ≤ 300 mm, 200 mm ≤ focal length of the second lens ≤ 300 mm, 50 mm ≤ focal length of the third lens ≤ 100 mm, -100 mm ≤ focal length of the fourth lens ≤ -50 mm, -50 mm ≤ focal length of the fifth lens ≤ -21 mm, 20 mm ≤ focal length of the sixth lens ≤ 50 mm, 50 mm ≤ focal length of the seventh lens ≤ 100 mm, -100 mm ≤ focal length of the eighth lens ≤ -50 mm, 50 mm ≤ focal length of the ninth lens ≤ 100 mm, and -50 mm ≤ focal length of the tenth lens ≤ -20 mm.

3. The fixed-focus broadband objective lens for a large target detector according to claim 1, characterized in that: All ten lenses in the objective lens body are spherical lenses.

4. A fixed-focus broadband objective lens for a large target detector according to claim 1, characterized in that: The third lens is cemented with the fourth lens, the fifth lens is cemented with the sixth lens, and the seventh lens is cemented with the eighth lens.

5. A fixed-focus broadband objective lens for a large target detector according to claim 4, characterized in that: The cemented lens uses a combination of crown glass and heavy flint glass.

6. A fixed-focus broadband objective lens for a large target detector according to claim 1, characterized in that: The objective lens has an optical length of 150 mm, a field of view of 10°, an F number of 1.4, a focal length of 93 mm, and a working spectral range of 460-900 nm.

7. A fixed-focus broadband objective lens for a large target detector according to claim 1, characterized in that: The objective lens body is suitable for a 1-inch detector with dimensions of 13.14 mm × 8.76 mm, and can be adapted to detectors with a maximum diameter of 8 mm.

8. A fixed-focus broadband objective lens for a large target detector according to claim 1, characterized in that: The objective lens body has a central field-of-view optical transfer function greater than 0.5 and an edge field-of-view optical transfer function greater than 0.3 at a spatial frequency of 0~100 lp / mm.

9. A fixed-focus broadband objective lens for a large target detector according to claim 1, characterized in that: The RMS spot radius of the objective lens body is 5 μm in the main field of view and 6 μm in the peripheral field of view.

10. A fixed-focus wide-spectrum objective lens applied to a large-area detector according to claim 1, characterized in that: The maximum distortion of the objective lens body is 0.02%.

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