Device and method for assembling and adjusting front focusing large objective lens group of zoom lens

Abstract

The invention belongs to the technical field of installation and adjustment, and particularly relates to an installation and adjustment device and method for a front focusing large objective lens group of a zoom lens. The method comprises the following steps: S1, establishing an adjusting device of a front focusing large objective lens group of the zoom lens; s2, controlling each motor to enable the optical axis of the first lens to be coaxial with the optical axis of the zoom lens; s3, controlling each motor according to an acquisition result of the aberration Zernike coefficient acquisition unit, and adjusting the position of the first lens base by using each motor until the aberration Zernike coefficient is the minimum value; and S4, controlling each motor according to an acquisition result of the aberration Zernike coefficient acquisition unit, and adjusting the angle of the first lens base by using each motor until the aberration Zernike coefficient is the minimum value. According to the invention, the adjustment of the front focusing large objective lens group can be rapidly and accurately completed.

Description

Technical Field

[0001] The invention belongs to the technical field of installation and adjustment, and in particular relates to an installation and adjustment device and method for a front focusing large objective lens group of a zoom lens. Background Art

[0002] With the vigorous development of my country's scientific undertakings, zoom optical lenses are increasingly used in various fields such as aerospace and national defense. Zoom optical lenses have the problem of insufficient parfocality, which leads to a decrease in the imaging quality of close-range targets. In order to achieve close-range parfocality of zoom optical lenses, the front group focusing method will be used to solve this problem. The traditional front group focusing zoom structure requires high installation accuracy, and the installation method is complex and difficult. Summary of the invention

[0003] In view of this, the invention aims to provide a device and method for adjusting the front focusing large objective lens group of a zoom lens, so as to solve the problems of high difficulty of traditional manual adjustment, inappropriate accessories and the like during the adjustment process, long adjustment time, and the inability to complete the adjustment work with high adjustment precision without certain experience. The adjustment method of the invention is not only efficient, but also greatly reduces the adjustment experience and ability requirements of the adjustment personnel, and the adjustment can be completed quickly only according to the inherent process.

[0004] To achieve the above object, the technical solution created by the present invention is implemented as follows: The invention discloses an adjustment device for a front focusing large objective lens group of a zoom lens, comprising a control unit and two tooling units, wherein the tooling unit comprises a grating ruler, a motor, a mounting seat and a fixing member, wherein the grating ruler and the motor are both fixedly mounted on the mounting seat, and the output shaft of the motor passes through the fixing member, and the fixing member is also fixed to a first lens seat by bolts. The control unit adjusts the control parameters of the motor based on feedback information of the grating ruler and the aberration Zernike coefficient of the front focusing large objective lens group, so that the motor drives the fixing member to move, and the fixing mechanism drives the first lens seat to move, thereby realizing the adjustment of the front focusing large objective lens group.

[0005] Furthermore, the front focusing large objective lens group also includes a lens barrel and a second lens mount, the first lens mount and the second lens mount are sequentially assembled in the lens barrel, a mounting groove is provided on the lens barrel relative to the position of the first lens mount, the first lens mount is equipped with a first lens, the second lens mount is sequentially equipped with a second lens and a third lens, the second lens is located between the first lens and the third lens, and the first lens is close to the object plane of the zoom lens.

[0006] Furthermore, the number of the mounting grooves is the same as the number of the tooling units, the mounting grooves are symmetrically arranged on the lens barrel, and the fixing member passes through the mounting grooves and contacts the first lens seat.

[0007] Furthermore, the control unit includes a motor control unit, a grating scale acquisition unit and an aberration Zernike coefficient acquisition unit. The grating scale acquisition unit acquires the position and angle of the first lens fed back by the grating scale, the aberration Zernike coefficient acquisition unit acquires the aberration Zernike coefficient of the front group of focusing large objective lens groups, and the motor control unit adjusts the control parameters of the motor.

[0008] A method for assembling and adjusting a front focusing large objective lens group of a zoom lens is implemented by using an assembling and adjusting device for the front focusing large objective lens group of the zoom lens, and specifically comprises the following steps: S1: Build the installation and adjustment device of the front focusing large objective lens group of the zoom lens; S2: According to the position and angle of the first lens acquired by the grating ruler acquisition unit, control each motor to make the optical axis of the first lens coaxial with the optical axis of the zoom lens; S3: using an interferometer to measure the aberration Zernike coefficient of the front focusing large objective lens group, and controlling each motor according to the collection result of the aberration Zernike coefficient collection unit, and using each motor to adjust the position of the first lens seat until the aberration Zernike coefficient is the minimum value; S4: Controlling each motor according to the collection result of the aberration Zernike coefficient collection unit, and using each motor to adjust the angle of the first mirror mount until the aberration Zernike coefficient is a minimum value.

[0009] Furthermore, in step S3, each motor drives each fixing member to move synchronously in the same direction to adjust the position of the first mirror mount.

[0010] Furthermore, in step S4, each motor drives each fixing member to move synchronously in opposite directions to adjust the angle of the first mirror mount.

[0011] Further, in step S3 and step S4, when the aberration Zernike coefficient is at a minimum value, the aberration Zernike coefficient is less than 0.5λ.

[0012] Furthermore, λ is the wavelength of the laser emitted by the interferometer.

[0013] Compared with the prior art, the invention can achieve the following beneficial effects: (1) The method for assembling and adjusting the front focusing large objective lens group of the zoom lens created by the present invention can not only solve the problem of insufficient parfocality of the zoom lens at close range, but also greatly improve the optical and mechanical assembly accuracy and work efficiency.

[0014] (2) The present invention creates a method for assembling and adjusting the front focusing large objective lens group of the zoom lens, which is a high-precision and high-efficiency optical lens adjustment device and control method. The present invention is based on the real-time feedback mechanism of the grating ruler and the interferometer to achieve fine adjustment of the position and angle of the first lens, meeting the requirements for the continuous improvement of the accuracy of the optical system. The device of the present invention is simple and easy to use, suitable for the needs of focusing and aberration correction of various optical devices, and improves the performance and stability of optical devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 A schematic diagram of the structure of the mounting device of the front focusing large objective lens group of the zoom lens according to the embodiment of the present invention; Figure 2 The present invention is a flowchart of a method for assembling and adjusting a front focusing large objective lens group of a zoom lens according to an embodiment of the present invention.

[0016] Description of reference numerals: 1. Grating ruler; 2. Motor; 3. Mounting seat; 4. Fixing part; 5. First mirror seat; 6. First lens. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0018] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0020] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0021] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0022] like Figure 1 As shown, the present invention provides an adjustment device for a front group focusing large objective lens group of a zoom lens, comprising a control unit and two tooling units, the tooling unit comprising a grating ruler 1, a motor 2, a mounting seat 3 and a fixing member 4, the grating ruler 1 and the motor 2 are both fixedly mounted on the mounting seat 3, the output shaft of the motor 2 passes through the fixing member 4, and the fixing member 4 is also fixed to the first lens seat 5 by bolts, the control unit adjusts the control parameters of the motor 2 based on the feedback information of the grating ruler 1 and the aberration Zernike coefficient of the front group focusing large objective lens group, so that the motor 2 drives the fixing member 4 to move, and the fixing mechanism drives the first lens seat 5 to move, thereby realizing the adjustment of the front group focusing large objective lens group.

[0023] The front focusing large objective lens group also includes a lens barrel and a second lens seat. The first lens seat 5 and the second lens seat are assembled in sequence in the lens barrel. A mounting groove is provided on the lens barrel relative to the first lens seat 5 (the mounting groove can be a rectangular mounting groove, so that the fixing member 4 will not shake in directions other than the output shaft direction of the motor 2 during movement). The fixing member 4 is fixed to the first lens seat 5 through the mounting groove. The width of the fixing member 4 is smaller than the width of the mounting groove, ensuring that the fixing member 4 drives the first lens seat 5 to move along the output shaft direction of the motor 2 (inward or outward) in the mounting groove. The first lens seat 5 is equipped with a first lens 6, and the second lens seat is equipped with a second lens and a third lens in sequence. The second lens is located between the first lens 6 and the third lens, and the first lens 6 is close to the object plane of the zoom lens.

[0024] The number of the mounting grooves is the same as the number of the tooling units. The mounting grooves are symmetrically arranged on the lens barrel. The fixing member 4 passes through the mounting grooves and contacts the first lens seat 5 .

[0025] The control unit includes a motor 2 control unit, a grating scale 1 acquisition unit and an aberration Zernike coefficient acquisition unit. The grating scale 1 acquisition unit acquires the position and angle of the first lens 6 fed back by the grating scale 1, the aberration Zernike coefficient acquisition unit acquires the aberration Zernike coefficient of the front group of focusing large objective lens groups, and the motor 2 control unit adjusts the control parameters of the motor 2.

[0026] like Figure 2 As shown, the present invention provides a method for assembling and adjusting a front focusing large objective lens group of a zoom lens, which is implemented by using an assembling and adjusting device for a front focusing large objective lens group of a zoom lens, and specifically comprises the following steps: S1: Build the mounting device for the front focusing large objective lens group of the zoom lens.

[0027] S2: According to the position and angle of the first lens 6 acquired by the acquisition unit of the grating ruler 1, each motor 2 is controlled to make the optical axis of the first lens 6 coaxial with the optical axis of the zoom lens.

[0028] S3: using an interferometer (the interferometer is placed at one end close to the first lens 6) to measure the aberration Zernike coefficient of the front focusing large objective lens group, and controlling each motor 2 according to the collection result of the aberration Zernike coefficient collection unit, and using each motor 2 to adjust the position of the first lens holder 5 until the aberration Zernike coefficient is the minimum value; In step S3 , each motor 2 drives each fixing member 4 to move synchronously in the same direction (along the output shaft direction of the motor 2 ) to adjust the position of the first mirror holder 5 .

[0029] S4: controlling each motor 2 according to the collection result of the aberration Zernike coefficient collection unit, and using each motor 2 to adjust the angle of the first lens holder 5 until the aberration Zernike coefficient reaches a minimum value.

[0030] In step S4 , each motor 2 drives each fixing member 4 to move synchronously in the opposite direction (along the output shaft direction of the motor 2 ) to adjust the angle of the first mirror holder 5 .

[0031] In step S3 and step S4, when the aberration Zernike coefficient is at a minimum value, the aberration Zernike coefficient is less than 0.5λ, where λ is the wavelength of the laser emitted by the interferometer.

[0032] The adjustment method of the present invention divides the automatic adjustment into two parts. One part is to adjust and fix the first lens 6 by using a tooling unit, and the tooling unit includes a motor 2 for providing driving force and a position feedback element-a grating ruler 1; the other part is an embedded control system-a control unit, including a motor 2 control unit, a grating ruler 1 acquisition unit and an aberration Zernike coefficient acquisition unit. The control unit includes a host computer and FGGA, etc.

[0033] Principle of automatic adjustment: the control unit determines the position and angle of the first lens 6 through the grating ruler 1, first adjusts the first lens 6 to 0 degrees, so that the first lens 6 is perpendicular to the optical path, and then controls the two motors 2 to adjust synchronously, so as to adjust the entire optical path of the front group focusing large objective lens group, measures the aberration Zernike coefficient through the interferometer, and records the corresponding relationship between the position of the first lens 6 (the feedback information of the grating ruler 1) and the aberration Zernike coefficient value of the entire stroke, and uses the control unit to adjust the first lens 6 to the position with the minimum aberration Zernike coefficient value, and the automatic adjustment of this position is completed; similarly, according to different types of lenses, the two motors 2 are controlled to perform reverse synchronous adjustment, and the lens is offset at the position with the minimum aberration Zernike coefficient value, and the control unit records the relationship between the lens angle (the difference between the grating ruler 1 and the optimal position) and the aberration Zernike coefficient value. At this time, the control unit adjusts the first lens 6 to the angle with the minimum aberration Zernike coefficient value, and the position and angle adjustment are completed. At this time, the aberration Zernike coefficient value has also reached the minimum, reaching the optimal position for adjustment, and the fine adjustment of the front group focusing large objective lens group is automatically completed.

[0034] After finishing the fine adjustment, the motor 2 and the grating ruler 1 are separated from the fixing part 4, including the embedded control system. When automatic adjustment is needed later, the motor 2 and the grating ruler 1 only need to be installed on the new fixing part 4.

[0035] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0036] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A device for assembling and adjusting a front focusing large objective lens group of a zoom lens, characterized in that: The invention comprises a control unit and two tooling units, wherein the tooling units comprise a grating scale, a motor, a mounting seat and a fixing part, wherein the grating scale and the motor are both fixedly mounted on the mounting seat, and the output shaft of the motor passes through the fixing part, and the fixing part is also fixed to the first lens seat by bolts. The control unit adjusts the control parameters of the motor based on the feedback information of the grating scale and the aberration Zernike coefficient of the front group focusing large objective lens group, so that the motor drives the fixing part to move, and the fixing mechanism drives the first lens seat to move, thereby realizing the installation and adjustment of the front group focusing large objective lens group.

2. The device for assembling and adjusting the front focusing large objective lens group of the zoom lens according to claim 1, characterized in that: The front focusing large objective lens group also includes a lens barrel and a second lens seat, the first lens seat and the second lens seat are sequentially assembled in the lens barrel, a mounting groove is provided on the lens barrel relative to the position of the first lens seat, the first lens seat is equipped with a first lens, the second lens seat is sequentially equipped with a second lens and a third lens, the second lens is located between the first lens and the third lens, and the first lens is close to the object plane of the zoom lens.

3. The device for assembling and adjusting the front focusing large objective lens group of the zoom lens according to claim 2, characterized in that: The number of the mounting grooves is the same as the number of the tooling units, the mounting grooves are symmetrically arranged on the lens barrel, and the fixing member passes through the mounting grooves and contacts the first lens seat.

4. The device for assembling and adjusting the front focusing large objective lens group of the zoom lens according to claim 1, characterized in that: The control unit includes a motor control unit, a grating scale acquisition unit and an aberration Zernike coefficient acquisition unit. The grating scale acquisition unit acquires the position and angle of the first lens fed back by the grating scale, the aberration Zernike coefficient acquisition unit acquires the aberration Zernike coefficient of the front group of focusing large objective lens group, and the motor control unit adjusts the control parameters of the motor.

5. A method for assembling and adjusting a front focusing large objective lens group of a zoom lens, which is implemented by using the assembling and adjusting device for the front focusing large objective lens group of a zoom lens according to any one of claims 1 to 4, characterized in that: The specific steps include: S1: Build the installation and adjustment device of the front focusing large objective lens group of the zoom lens; S2: According to the position and angle of the first lens acquired by the grating ruler acquisition unit, control each motor to make the optical axis of the first lens coaxial with the optical axis of the zoom lens; S3: using an interferometer to measure the aberration Zernike coefficient of the front focusing large objective lens group, and controlling each motor according to the collection result of the aberration Zernike coefficient collection unit, and using each motor to adjust the position of the first lens seat until the aberration Zernike coefficient is a minimum value; S4: controlling each motor according to the acquisition result of the aberration Zernike coefficient acquisition unit, and using each motor to adjust the angle of the first lens mount until the aberration Zernike coefficient is a minimum value.

6. The method for assembling and adjusting the front focusing large objective lens group of the zoom lens according to claim 5, characterized in that: In step S3, each motor drives each fixing member to move synchronously in the same direction to adjust the position of the first mirror seat.

7. The method for assembling and adjusting the front focusing large objective lens group of the zoom lens according to claim 5, characterized in that: In step S4, each motor drives each fixing member to move synchronously in opposite directions to adjust the angle of the first mirror seat.

8. The method for assembling and adjusting the front focusing large objective lens group of the zoom lens according to claim 5, characterized in that: In step S3 and step S4, when the aberration Zernike coefficient is at a minimum value, the aberration Zernike coefficient is less than 0.5λ.

9. The method for assembling and adjusting the front focusing large objective lens group of the zoom lens according to claim 8, characterized in that: λ is the wavelength of the laser emitted by the interferometer.

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