A wideband collimator lens

Abstract

The present application relates to a kind of wide-band collimating lens, the lens is sequentially arranged by first lens, second lens, third lens, fourth lens, fifth lens, sixth lens along optical axis, aperture diaphragm is coaxially arranged in the rear of sixth lens;Wherein first lens, third lens, fourth lens, sixth lens are double convex lens, third lens, fifth lens are double concave lens;Target is set on the front focal point of lens group, and the 300-1000nm waveband radiation light emitted by it is collimated into parallel light after passing through lens group, and is received at aperture diaphragm by the multispectral imaging system to be measured.The present application can collimate the 300-1000nm waveband radiation emitted by target, simulate a wide-band test pattern with exit field angle ±3.5°, and provide a kind of lens device with light weight, small size, high efficiency for the assembly and debugging of multispectral imaging lens.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of optical lens, and relates to an optical lens capable of collimating and outputting target radiation in a 300-1000nm wave band. BACKGROUND

[0002] A multi-spectral imaging system can simultaneously acquire images of a target in multiple spectral wave bands, and the images can reflect optical information that cannot be revealed by a conventional imaging system after information fusion. For multiple imaging channels in the multi-spectral system, the consistency of optical axes needs to be well adjusted, which requires a wide-spectrum collimation system with a common optical axis and covering the spectral channels, and an optical collimation lens is a core component.

[0003] A conventional scheme of the wide-spectrum collimation lens is to use an off-axis parabolic mirror or a Cassegrain reflective lens. Although these schemes are based on a reflective optical path and are suitable for a relatively wide working wave band, they all have defects of small field of view angle, large volume or existence of central obstruction. SUMMARY

[0004] The application aims to solve the technical problem of providing a wide-band collimation lens, which is a transmissive collimation lens for a working wave band of 300-1000nm, and can solve the limitations of small field of view angle, large volume or existence of central obstruction of a reflective wide-band collimation lens.

[0005] In order to solve the above technical problem, the wide-band collimation lens comprises a lens group composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged along an optical axis in sequence, and an aperture diaphragm coaxially arranged at the rear of the sixth lens; wherein the first lens, the third lens, the fourth lens and the sixth lens are double convex lenses, and the second lens and the fifth lens are double concave lenses; a target is arranged at the front focal point of the lens group, and the 300-1000nm wave band radiation light emitted by the target is collimated into parallel light after passing through the lens group and is received by a multi-spectral imaging system to be detected at the aperture diaphragm.

[0006] The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are respectively made of calcium fluoride, JGS1, calcium fluoride, calcium fluoride, JGS1 and calcium fluoride.

[0007] The first lens, the second lens and the third lens form a front lens group, and the fourth lens, the fifth lens and the sixth lens form a rear lens group, and the total focal length ratio of the front lens group to the rear lens group is 1: (1.15-1.25).

[0008] The total focal length of the front lens group is 75mm, and the total focal length of the rear lens group is 90mm.

[0009] The focal length distribution ratio of the first lens, the second lens and the third lens is 2: (-0.9~ -1.1): (0.9~1.1); the focal length distribution ratio of the fourth lens, the fifth lens and the sixth lens is 1.5: (-0.9~ -1.1): (1.65~1.75).

[0010] The focal length of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens is 67.03mm, -30.97mm, 34.22mm, 43.24mm, -30.02mm and 49.65mm respectively.

[0011] The lens parameters are shown in Table 1, wherein Ri is the curvature radius of the i-th optical surface, ti is the thickness of the i-th lens, and di is the air gap between the i-th lens and the next optical surface.

[0012] Table 1

[0013]

[0014] Beneficial effects:

[0015] The application utilizes the transmission type wide waveband collimating lens, can collimate the 300~1000nm waveband radiation emitted by the target, simulates a wide waveband test pattern with an exit field angle of ±3.5°, and provides a light weight, small size, efficient lens device for the assembly and debugging of the multi-spectrum imaging lens. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a structural schematic diagram of the application.

[0017] Figure 2 is a modulation transfer function curve diagram of the embodiment of the application.

[0018] In the figure: 1. target, 2. first lens, 3. second lens, 4. third lens, 5. fourth lens, 6. fifth lens, 7. sixth lens, 8. aperture stop. DETAILED DESCRIPTION

[0019] The application will be further described in detail below in combination with the drawings and embodiments, and it can be understood that the specific embodiments described herein are only used to explain the application, but not to limit the application. In addition, it should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings, but not all the structures.

[0020] In the description of the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, it can be the internal communication of two elements or the interaction relationship of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0021] In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0022] In the description of the present embodiment, the terms "up", "down", "left", "right" and other orientation or position relationship are based on the orientation or position relationship shown in the drawings, which is only for the convenience of description and simplification of operation, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0023] As shown in Figure 1 The wide-band collimator lens of the present application is composed of a first lens 2, a second lens 3, a third lens 4, a fourth lens 5, a fifth lens 6, a sixth lens 7 and an aperture stop 8 arranged in sequence along the optical axis; a target 1 is located on the front focal point of the lens group composed of the first lens 2, the second lens 3, the third lens 4, the fourth lens 5, the fifth lens 6 and the sixth lens 7; the target 1 emits 300-1000nm band radiation light after being illuminated by a light source, which is collimated into parallel light after passing through the lens group, and is received by a multi-spectral imaging system to be tested at the aperture stop 8.

[0024] The first lens, the second lens and the third lens constitute a front lens group, and the total focal length is 75mm; the focal length distribution ratio of the first lens, the second lens and the third lens is about 2:-1:1. The fourth lens 5, the fifth lens 6 and the sixth lens 7 constitute a rear lens, and the total focal length is 90mm, and the focal length distribution ratio of the fourth lens 5, the fifth lens 6 and the sixth lens 7 is about 1.5:-1:1.7.

[0025] The first lens 2 adopts calcium fluoride material, has positive focal power, is a biconvex lens; the second lens 3 adopts JGS1 material, has negative focal power, is a biconcave lens; the third lens 4 adopts calcium fluoride material, has positive focal power, is a biconvex lens; the fourth lens 5 adopts calcium fluoride material, has positive focal power, is a biconvex lens; the fifth lens 6 adopts JGS1 material, has negative focal power, is a biconcave lens; the sixth lens 7 adopts calcium fluoride material, has positive focal power, is a biconvex lens.

[0026] The wave band selected by the system design of the present application is 300nm~1000nm; the object plane size, i.e. the effective size of the target 1 is 6.1mm; the total focal length of the collimating light path is 50mm; the diameter of the aperture stop 8 is 18mm; the exit field angle of the system is ±3.5°.

[0027] Specifically, the focal lengths of the first lens 2, the second lens 3, the third lens 4, the fourth lens 5, the fifth lens 6 and the sixth lens 7 are 67.03mm, -30.97mm, 34.22mm, 43.24mm, -30.02mm and 49.65mm respectively; the specific parameters of each lens are shown in Table 1, in which Ri represents the curvature radius of the i-th optical surface, ti represents the thickness of the i-th lens, and di represents the air gap from the rear surface of the i-th lens to the next optical surface. The modulation transfer function curves of the present embodiment at the exit half field angles of 0°, 2° and 3.5° are shown in Figure 2 The modulation transfer function values of each field in the figure are all higher than 0.6 at 1cy / mrad, which indicates that the projection image of the lens in the wave band of 300~1000nm has high spatial resolution.

[0028] Table 1

[0029]

[0030] The present application aims to provide a transmission type collimating lens with a working wave band of 300nm~1000nm, which can produce the required 300nm~1000nm large field image in cooperation with a target and an illumination light source, and is used for the assembly and detection of a multi-spectral imaging system. The working wave band is relatively wide, and good quality projection images can be obtained from ultraviolet to near infrared wave band.

Claims

1. A wide-band collimator lens, characterized by The lens group is composed of a first lens (2), a second lens (3), a third lens (4), a fourth lens (5), a fifth lens (6) and a sixth lens (7) arranged along the optical axis in sequence, and an aperture stop (8) is coaxially arranged behind the sixth lens (7); wherein the first lens (2), the third lens (4), the fourth lens (5) and the sixth lens (7) are double convex lenses, and the second lens (3) and the fifth lens (6) are double concave lenses; the target (1) is arranged on the front focal point of the lens group, and the 300-1000nm waveband radiation light emitted by the target is collimated into parallel light after passing through the lens group and is received by the multi-spectral imaging system to be detected at the aperture stop (8).

2. The wide-band collimator lens of claim 1, wherein The materials of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are calcium fluoride, JGS1, calcium fluoride, calcium fluoride, JGS1 and calcium fluoride respectively.

3. The wide-band collimator lens of claim 1, wherein The first lens, the second lens and the third lens constitute a front lens group, and the fourth lens, the fifth lens and the sixth lens constitute a rear lens group, and the total focal length ratio of the front lens group to the rear lens group is 1: (1.15-1.25).

4. The wide-band collimator lens of claim 3, wherein The total focal length of the front lens group is 75mm, and the total focal length of the rear lens group is 90mm.

5. The wide-band collimator lens of claim 3, wherein The focal length distribution ratio of the first lens, the second lens and the third lens is 2: (-0.9--1.1): (0.9-1.1), and the focal length distribution ratio of the fourth lens, the fifth lens and the sixth lens is 1.5: (-0.9--1.1): (1.65-1.75).

6. The wide-band collimator lens of claim 5, wherein The focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are 67.03mm, -30.97mm, 34.22mm, 43.24mm, -30.02mm and 49.65mm respectively.

7. The wide-band collimator lens of claim 1, wherein The lens parameters are shown in Table 1, wherein Ri is the curvature radius of the i-th optical surface, ti is the thickness of the i-th lens, and di is the air gap between the i-th lens and the next optical surface. Table 1 。

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