A large zoom ratio high-definition zoom lens

Abstract

The application belongs to the technical field of vehicle optical instruments, and discloses a high-magnification-ratio high-definition zoom lens, which comprises a positive-power front fixed lens group, a negative-power zoom lens group, a negative-power compensation lens group, an aperture diaphragm and a positive-power rear fixed lens group arranged in sequence from an object side to an image side. The application meets the requirements of large magnification ratio optical zoom, ultra-low astigmatism and distortion in a very small space, and can obtain high-precision image target directivity under the harsh environment conditions of military vehicles.

Description

Technical Field

[0001] This invention belongs to the field of vehicle optical instrument technology, and in particular relates to a high-resolution zoom lens with a large zoom ratio. Background Technology

[0002] Existing military vehicle-mounted visible light zoom lenses have a maximum zoom ratio of 6x, which cannot simultaneously meet the needs of target observation and search in a large market with short focal lengths, and target aiming and tracking in a small field of view with long focal lengths. Moreover, as the optical zoom ratio increases, many problems are exposed: poor target pointing accuracy during zooming; and high tolerance requirements leading to poor product manufacturability. Summary of the Invention

[0003] The technical problem to be solved by this invention is that, when the optical zoom magnification increases, the target pointing accuracy of existing military vehicle-mounted visible light zoom lenses is poor during the zoom process; and the high tolerance requirements lead to poor product manufacturability.

[0004] To solve the above-mentioned technical problems, the specific technical solution of the present invention is as follows:

[0005] A high-resolution zoom lens with a large zoom ratio includes a front fixed lens group with positive optical power, a zoom lens group with negative optical power, a compensation lens group with negative optical power, an aperture stop, and a rear fixed lens group with positive optical power arranged sequentially from the object side to the image side.

[0006] Furthermore, the positive optical power front fixed lens group includes a first positive optical power lens, a first negative optical power lens group, and a second positive optical power lens arranged sequentially.

[0007] Furthermore, the negative optical power zoom lens group includes a third positive optical power lens group, a second negative optical power lens, and a third negative optical power lens arranged sequentially.

[0008] Furthermore, the negative optical power compensation lens group includes a fourth positive optical power lens group, a fourth negative optical power lens, and a fifth negative optical power lens arranged sequentially.

[0009] Furthermore, the positive optical power fixed lens group includes a fifth positive optical power lens group, a sixth positive optical power lens group, a sixth negative optical power lens group, a seventh negative optical power lens group, and a seventh positive optical power lens arranged sequentially.

[0010] Furthermore, the aperture stop has a constant size, is fixed at the front end of the rear fixed lens group, and is fixed together with it.

[0011] Furthermore, the negative optical power zoom lens group includes at least one meniscus lens, which has a negative optical power.

[0012] Furthermore, the negative optical power zoom lens group includes at least one lens with a surface curvature radius of 0.

[0013] Furthermore, the surface with a radius of curvature of 0 is coated with a narrow-band cutoff filter film.

[0014] Furthermore, the lens's F-number remains constant throughout the zoom process, satisfying F# = 4.15.

[0015] The present invention has the following advantages:

[0016] 1. High-definition resolution, maintaining an optical transfer function (MTF) of 110 / mm above 0.4 throughout 15x continuous zoom.

[0017] 2. The F-number is fixed throughout the entire range, satisfying F# = 4.15, which can provide sufficiently high energy for long-focus aiming optical systems.

[0018] 3. Ultra-low astigmatism and ultra-low distortion at the telephoto end provide sufficiently clear and reliable images for target aiming and tracking. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the high zoom ratio high-definition zoom lens structure of the present invention;

[0020] The markings in the diagram are as follows: 1 is the first positive power lens, 2 is the first negative power lens group, 3 is the second positive power lens, 4 is the third positive power lens group, 5 is the second negative power lens, 6 is the third negative power lens, 7 is the fourth positive power lens group, 8 is the fourth negative power lens, 9 is the fifth negative power lens, 10 is the fifth positive power lens group, 11 is the sixth positive power lens, 12 is the sixth negative power lens group, 13 is the seventh negative power lens, and 14 is the seventh positive power lens. Detailed Implementation

[0021] To better understand the purpose, structure, and function of this invention, the invention will be described in further detail below with reference to the accompanying drawings.

[0022] like Figure 1 As shown, the high zoom ratio high-definition zoom lens of the present invention includes a positive optical power front fixed lens group, a negative optical power zoom lens group, a negative optical power compensation lens group, an aperture stop, and a positive optical power rear fixed lens group arranged sequentially from the object side to the image side.

[0023] The lens's F-number remains constant throughout the zoom process, satisfying F# = 4.15.

[0024] The positive power front fixed lens group includes: a first positive power lens and a first negative power lens group that can be cemented together to form a cemented lens group, arranged in sequence, and a second positive power lens.

[0025] The negative optical power zoom lens group includes: a third positive optical power lens group, a second negative optical power lens, and a third negative optical power lens arranged sequentially and cemented together to form a cemented lens group.

[0026] The negative optical power compensation lens group includes: a fourth positive optical power lens group, a fourth negative optical power lens, and a fifth negative optical power lens, which can be cemented together as a cemented lens group, arranged sequentially.

[0027] The positive optical power fixed lens group includes: a fifth positive optical power lens group, a sixth positive optical power lens, a sixth negative optical power lens group, a seventh negative optical power lens, and a seventh positive optical power lens, which can be cemented together as a cemented lens group, arranged sequentially.

[0028] The aperture stop has a constant size and is fixed at the front end of the rear fixed lens group and is fixed together with it.

[0029] All of the above lenses are spherical lenses.

[0030] The negative optical power zoom lens group includes at least one meniscus lens with negative optical power; at least one lens surface has a radius of curvature of 0. The surface with a radius of curvature of 0 is coated with a narrow-band cutoff filter for laser protection.

[0031] Table 1 shows the lens parameters and positional relationships in the embodiments of the present invention. Numbers 1-14 in the table represent... Figure 1 The corresponding number indicates the lens group; the radius of curvature represents the radius of curvature of each surface in the lens group from left to right; glass thickness / air gap indicates the thickness of the glass material or the center spacing of the lens position; glass material lists the glass material of each lens; and aperture indicates the optical light transmission size of each surface.

[0032] Compared with the prior art, the present invention has the following technical effects:

[0033] 1. High-definition resolution, maintaining an optical transfer function (MTF) of 110 / mm above 0.4 throughout 15x continuous zoom.

[0034] 2. The F-number is fixed throughout the entire range, satisfying F# = 4.15, which can provide sufficiently high energy for long-focus aiming optical systems.

[0035] 3. Ultra-low astigmatism and ultra-low distortion at the telephoto end provide sufficiently clear and reliable images for target aiming and tracking.

[0036] It achieves high-magnification optical zoom, ultra-low astigmatism and distortion in a very small space, and can obtain high-precision image target directionality under the harsh environment of military vehicles. Furthermore, by setting the size and position of the aperture stop, the diffraction limit at the telephoto end is improved, so that the lens can still provide high-resolution images during 15x optical zoom.

[0037] Table 1

[0038]

[0039] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art will be able to make various modifications and improvements without departing from the principles of the present invention, and these modifications and improvements should also be considered to fall within the scope of protection of the present invention.

Claims

1. A high-resolution zoom lens with a large zoom ratio, characterized in that, It includes a positive optical power front fixed lens group, a negative optical power zoom lens group, a negative optical power compensation lens group, an aperture stop, and a positive optical power rear fixed lens group arranged sequentially from the object side to the image side. The positive power front fixed lens group includes a first positive power lens, a first negative power lens group, and a second positive power lens arranged sequentially. The negative power zoom lens group includes a third positive power lens group, a second negative power lens, and a third negative power lens arranged sequentially. The negative power compensation lens group includes a fourth positive power lens group, a fourth negative power lens, and a fifth negative power lens arranged sequentially. The positive optical power fixed lens group includes a fifth positive optical power lens group, a sixth positive optical power lens group, a sixth negative optical power lens group, a seventh negative optical power lens group, and a seventh positive optical power lens arranged sequentially.

2. The high-resolution zoom lens with a large zoom ratio according to claim 1, characterized in that, The aperture stop has a constant size and is fixed at the front end of the rear fixed lens group, and is fixed together with it.

3. The high-resolution zoom lens with a large zoom ratio according to claim 1, characterized in that, The negative power zoom lens group includes at least one meniscus lens, which has a negative power.

4. The high-resolution zoom lens with a large zoom ratio according to claim 1, characterized in that, The negative optical power zoom lens group includes at least one lens with a surface curvature radius of 0.

5. The high-resolution zoom lens with a large zoom ratio according to claim 4, characterized in that, The surface with a radius of curvature of 0 is coated with a narrow-band cutoff filter.

6. The high-resolution zoom lens with a large zoom ratio according to any one of claims 1-5, characterized in that, The lens's F-number remains constant throughout the zoom process, satisfying F-number = 4.15.

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