Broadband spectrum laser beam shrinking lens

Abstract

The utility model discloses a wide-spectrum laser beam shrinking lens, which relates to the technical field of laser beam shrinking and comprises a window mirror, a front lens group with positive focal power and a rear lens group with negative focal power. The front lens group comprises a meniscus lens A, a meniscus lens B, a biconvex positive lens C and a plano-concave negative lens D which are arranged in sequence, the meniscus lens A, the meniscus lens B and the plano-concave negative lens D all have negative focal power, the biconvex positive lens C has positive focal power, the object side surfaces of the meniscus lens A and the meniscus lens B are convex surfaces, and the image side surfaces of the meniscus lens A and the meniscus lens B are concave surfaces; the object side surface and the image side surface of the biconvex positive lens C are convex surfaces; the object side surface of the plano-concave negative lens D is a concave surface, and the image side surface is a plane; and the rear lens group comprises a meniscus lens E with negative focal power. The objective of the utility model is to solve the technical problems that the conventional optical beam shrinking system cannot meet the calibration processing of light beams from visible light to infrared band, and the number of used lenses is large.

Description

Technical Field

[0001] This utility model relates to the field of laser beam shrinking technology, specifically to a broadband laser beam shrinking lens. Background Technology

[0002] In complex optomechanical systems such as laser communication and laser rangefinders, there are laser emission and imaging optical systems with the same aperture. These systems have many catadioptric and reflective circuits and long optical paths. In order to achieve accurate aiming and emission, it is necessary to calibrate the pupils of the emission and imaging systems. By using a laser beam-shrinking lens, the beams of the laser emission and imaging optical paths can be reduced and incident on the detector target surface, which is the calibration.

[0003] Currently, there are many technologies related to laser beam-shrinking lenses. For example, patent document CN117192789A discloses an infrared large-aperture optical beam-shrinking system, which includes: a first lens, a second lens, a first cemented lens, a third lens, a fourth lens, and a second cemented lens arranged sequentially along the main optical axis. The first, second, third, and fourth lenses are all spherical lenses, and the first and second cemented lenses are also spherical lenses. This optical beam-shrinking system has the advantage of improving optical quality. However, careful analysis reveals that in a laser emission and imaging co-aperture system, the beam requiring calibration covers the visible to infrared band. This optical beam-shrinking system can only process portions of the beam with wavelengths of 1.06 μm and 0.633 μm, meaning it cannot fully meet the calibration requirements for beams in the visible to infrared band. Furthermore, this optical beam-shrinking system requires eight lenses, resulting in a large number of lenses, higher production costs, and a more complex manufacturing process. Utility Model Content

[0004] To overcome the aforementioned problems in the prior art, this utility model provides a broadband laser beam-shrinking lens, which aims to solve the technical problems that existing optical beam-shrinking systems cannot fully meet the calibration processing requirements of beams from the visible to infrared bands, and that require a large number of lenses.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A broadband laser beam-shrinking lens includes a window mirror, a front lens group with positive optical power, and a rear lens group with negative optical power.

[0007] The window mirror, the front lens group, and the rear lens group are arranged sequentially from the object side to the image side along the optical axis;

[0008] The front lens group includes a meniscus lens A, a meniscus lens B, a biconvex positive lens C, and a plano-concave negative lens D arranged sequentially. Meniscus lenses A, B, and D all have negative optical power, while the biconvex positive lens C has positive optical power. The object-side surfaces of meniscus lenses A and B are both convex, and the image-side surfaces are both concave. The object-side surface and image-side surface of the biconvex positive lens C are both convex. The object-side surface of the plano-concave negative lens D is concave, and the image-side surface is planar.

[0009] The rear lens group includes a meniscus lens E with negative optical power. The object side of the meniscus lens E is convex, and the image side is concave.

[0010] Furthermore, the ratio of the incident beam diameter D to the outgoing beam diameter d of the broadband laser beam shrinking lens satisfies 19.5 < D / d < 20.5.

[0011] Furthermore, the ratio of the focal length f1 of the front lens group to the focal length f2 of the rear lens group satisfies -20.5 < f1 / f2 < -19.5.

[0012] Furthermore, the ratio of the focal length of the meniscus lens A to the focal length of the front lens group satisfies -15. <fA / f1<-14;

[0013] The ratio of the focal length of the meniscus lens B to the focal length of the front lens group satisfies -1.5. <fB / f1<-1.4;

[0014] The ratio of the focal length of the biconvex positive lens C to the focal length of the front lens group satisfies 0.3. <fC / f1<0.5;

[0015] The ratio of the focal length of the plano-concave negative lens D to the focal length of the front lens group satisfies -0.7. <fD / f1<-0.6;

[0016] The ratio of the focal length of the meniscus lens E to the focal length of the rear lens group satisfies -0.1. <fE / f2<-0.01。

[0017] The refractive index Nd of the meniscus lens A A And Abbe number Vd A The following condition must be met: 1.51 < Nd A <1.54, 64.1 <Vd A <64.5;

[0018] The refractive index Nd of the meniscus lens B B And Abbe number Vd B The following condition must be met: 1.90 < Nd B <1.95, 35.1 <Vd B <35.5;

[0019] The refractive index Nd of the biconvex positive lens C CAnd Abbe number Vd C The following condition must be met: 1.41 < Nd C <1.45, 94.3 <Vd C <94.8;

[0020] The refractive index Nd of the plano-concave negative lens D D And Abbe number Vd D The following condition must be met: 1.47 < Nd D <1.53, 70.1 <Vd D <71.2;

[0021] The refractive index NdE and Abbe number VdE of the meniscus lens E satisfy the following conditions: 1.50 < NdE < 1.55, 64.0 < VdE. E <64.5.

[0022] The advantages of using this utility model are:

[0023] 1. The beam-shrinking lens provided by this utility model can meet the beam calibration from visible light to near-infrared bands using only 5 lenses. Compared with the prior art, the calibration coverage is wide, the number of lenses used is small, and the lens materials are all common colorless glass, which not only reduces costs and simplifies the production process, but also makes it more adaptable to the environment.

[0024] 2. Through the specific combination of the above 5 lenses, as well as the specific beam diameter ratio and focal length ratio, this utility model is also conducive to improving the beam reduction ratio of the lens, specifically enabling the beam reduction ratio of the lens to reach about 20 times.

[0025] 3. Each lens of this invention uses a specific refractive index NdE and Abbe number VdE, which is beneficial to improving the quality of the beam. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the planar structure of this utility model;

[0027] Figure 2 It is a point array diagram of the image plane after the light beam passes through the laser beam-contracting lens of this utility model;

[0028] Figure 3 It is a phase-plane wavefront aberration diagram of the beam after passing through the laser beam-contracting lens of this utility model;

[0029] Figure 4 It is the image plane light trace diagram after the light beam passes through the laser beam-contracting lens of this utility model.

[0030] The markings in the diagram are: 1. Window mirror, 2. Meniscus lens A, 3. Meniscus lens B, 4. Biconvex positive lens C, 5. Plano-concave negative lens D, 6. Meniscus lens E. Detailed Implementation

[0031] As Figure 1 shown, the present utility model provides a wide-spectrum laser beam reducing lens, which includes a window lens 1, a front lens group, and a rear lens group sequentially arranged from the object side to the image side along the optical axis. The window lens 1 is used to protect the lens group. The front lens group has a positive optical power and is used to converge light. The rear lens group has a negative optical power and is used to collimate the light beam. Among them,

[0032] The front lens group includes a meniscus lens A2, a meniscus lens B3, a biconvex positive lens C4, and a plano-concave negative lens D5 arranged in sequence. The meniscus lens A2, the meniscus lens B3, and the plano-concave negative lens D5 all have negative optical powers, and the biconvex positive lens C4 has a positive optical power. The object sides of the meniscus lens A2 and the meniscus lens B3 are both convex surfaces, and the image sides are both concave surfaces; the object side and the image side of the biconvex positive lens C4 are both convex surfaces; the object side of the plano-concave negative lens D5 is a concave surface, and the image side is a plane; the rear lens group includes a meniscus lens E6 with a negative optical power. The object side of the meniscus lens E6 is a convex surface, and the image side is a concave surface.

[0033] Furthermore, the wide-spectrum laser beam reducing lens provided by the present utility model is applicable to a spectral range of 630 nm - 1064 nm. The ratio of the incident beam diameter D to the outgoing beam diameter d satisfies 19.5 < D / d < 20.5, and the ratio of the focal length f1 of the front lens group to the focal length f2 of the rear lens group satisfies -20.5 < f1 / f2 < -19.5. Preferably, the ratio D / d of the incident beam diameter D to the outgoing beam diameter d is 20, and the ratio f1 / f2 of the focal length f1 of the front lens group to the focal length f2 of the rear lens group is -20.

[0034] In the present utility model, the ratio of the focal length of the meniscus lens A2 to the focal length of the front lens group satisfies -15 < fA / f1 < -14; the ratio of the focal length of the meniscus lens B3 to the focal length of the front lens group satisfies -1.5 < fB / f1 < -1.4; the ratio of the focal length of the biconvex positive lens C4 to the focal length of the front lens group satisfies 0.3 < fC / f1 < 0.5; the ratio of the focal length of the plano-concave negative lens D5 to the focal length of the front lens group satisfies -0.7 < fD / f1 < -0.6; the ratio of the focal length of the meniscus lens E6 to the focal length of the rear lens group satisfies -0.1 < fE / f2 < -0.01.

[0035] Preferably, the ratio of the focal length of the meniscus lens A2 to the focal length of the front lens group is -14.5; the ratio of the focal length of the meniscus lens B3 to the focal length of the front lens group is -1.45; the ratio of the focal length of the biconvex positive lens C4 to the focal length of the front lens group is 0.4; the ratio of the focal length of the plano-concave negative lens D5 to the focal length of the front lens group is -0.65; the ratio of the focal length of the meniscus lens E6 to the focal length of the rear lens group is -0.05.

[0036] In the present utility model, the refractive index Nd of the meniscus lens A2A And Abbe number Vd A The following condition must be met: 1.51 < Nd A <1.54, 64.1 <Vd A <64.5; Refractive index Nd of meniscus lens B3 B And Abbe number Vd B The following condition must be met: 1.90 < Nd B <1.95, 35.1 <Vd B <35.5; the refractive index Nd of the biconvex positive lens C4 C And Abbe number Vd C The following condition must be met: 1.41 < Nd C <1.45, 94.3 <Vd C <94.8; Refractive index Nd of plano-concave negative lens D5 D And Abbe number Vd D The following condition must be met: 1.47 < Nd D <1.53, 70.1 <Vd D <71.2; The refractive index NdE and Abbe number VdE of the meniscus lens E6 satisfy the following conditions: 1.50 < NdE < 1.55, 64.0 < VdE. E <64.5.

[0037] Preferably, the refractive index Nd of the meniscus lens A2 is... A The Abbe number Vd is 1.52. A The refractive index Nd of meniscus lens B3 is 64.3. B The Abbe number Vd is 1.93. B The refractive index Nd of the biconvex positive lens C4 is 35.3. C The Abbe number Vd is 1.43. C The refractive index Nd of the plano-concave negative lens D5 is 94.5. D The Abbe number Vd is 1.5. D The refractive index NdE of the meniscus lens E6 is 1.52, and the Abbe number VdE is 64.2.

[0038] The following are a set of specific embodiments of this utility model. The parameters of the broadband laser beam-shrinking lens are shown in Table 1 below:

[0039]

[0040] As shown in Table 1 above, after the light beam passes through the lens represented by the parameters shown in Table 1, the resulting point array on the image plane is as follows: Figure 2 As shown, the light spot is basically within the diffraction-limited range, with an RMS radius of 0.248 mr, which is smaller than the diffraction limit of 0.3881 mr. The wavefront aberration of the beam on the image side is as follows: Figure 3As shown, its wavefront PV is 0.2981. @632.8nm, wavefront RMS is 0.09 @632.8nm, the beam trace on the side of the image is as follows Figure 4 As shown; by Figure 2 , Figure 3 and Figure 4 It is known that this broadband laser beam-shrinking lens can shrink a laser beam with a wavelength of 630nm~1064nm and a beam diameter of 40mm into a collimated laser beam with a maximum diameter of 2.03mm. The front and rear lens groups, which play the main role, consist of five lenses, all of which use commonly used colorless optical glass.

[0041] The above description is only a specific embodiment of the present utility model. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All features or steps in all methods or processes disclosed may be combined in any way except for mutually exclusive features and / or steps.

Claims

1. A wide-spectrum laser beam-reducing lens, characterized in that: The window mirror (1), the front lens group with positive optical power and the rear lens group with negative optical power are sequentially arranged along the optical axis from the object side to the image side. The window mirror (1), the front lens group and the rear lens group are sequentially arranged along the optical axis from the object side to the image side. The front lens group comprises a meniscus lens A (2), a meniscus lens B (3), a biconvex positive lens C (4) and a plano-concave negative lens D (5) sequentially arranged, the meniscus lens A (2), the meniscus lens B (3) and the plano-concave negative lens D (5) all have negative optical power, the biconvex positive lens C (4) has positive optical power, the object side surface of the meniscus lens A (2) and the meniscus lens B (3) are both convex, and the image side surfaces are both concave; the object side surface and the image side surface of the biconvex positive lens C (4) are both convex; the object side surface of the plano-concave negative lens D (5) is concave, and the image side surface is a plane. The rear lens group comprises a meniscus lens E (6) with negative optical power, the object side surface of the meniscus lens E (6) is convex, and the image side surface is concave.

2. A wide-spectrum laser beam shrinking lens according to claim 1, characterized in that: The ratio of the incident beam diameter D to the exit beam diameter d of the wide-spectrum laser beam expander satisfies 19.5 < D / d < 20.

5.

3. A wide-spectrum laser beam shrinking lens according to claim 1 or 2, characterized in that: The ratio of the focal length f1 of the front lens group to the focal length f2 of the rear lens group satisfies -20.5 < f1 / f2 < -19.

5.

4. The wide-spectrum laser beam shrinking lens according to claim 1, wherein: The ratio of the focal length of the meniscus lens A (2) to the focal length of the front lens group satisfies -15 < fA / f1 < -14. The ratio of the focal length of the meniscus lens B (3) to the focal length of the front lens group satisfies -1.5 < fB / f1 < -1.

4. The ratio of the focal length of the biconvex positive lens C (4) to the focal length of the front lens group satisfies 0.3 < fC / f1 < 0.

5. The ratio of the focal length of the plano-concave negative lens D (5) to the focal length of the front lens group satisfies -0.7 < fD / f1 < -0.

6. The ratio of the focal length of the meniscus lens E (6) to the focal length of the rear lens group satisfies -0.1 < fE / f2 < -0.

01.

5. A wide spectrum laser beam shrinking lens according to any one of claims 1, 2 or 4, characterized in that: The refractive index Nd of the meniscus lens A (2) A and the Abbe number Vd A satisfies the following conditions: 1.51 < Nd A < 1.54, 64.1 < Vd A < 64.5; The refractive index Nd of the meniscus lens B (3) B and the Abbe number Vd B satisfies the following conditions: 1.90 < Nd < 1.95, 35.1 < Vd < 35.5 B < 1.95, 35.1 < Vd < 35.5 B < 35.5; The refractive index Nd of the lenticular convex lens C (4) C and the Abbe number Vd C satisfies the following conditions: 1.41 < Nd C < 1.45, 94.3 < Vd C < 94.8; The refractive index Nd of the plano-concave negative lens D (5) D and the Abbe number Vd D satisfies the following conditions: 1.47 < Nd D < 1.53, 70.1 < Vd D < 71.2; The refractive index NdE and the Abbe number VdE of the meniscus lens E (6) satisfy the following conditions: 1.50 < NdE < 1.55, 64.0 < VdE < 64.

5. E <64.5.

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