A miniaturized continuous zoom lens and its design method

Abstract

The present invention discloses a design method for a miniaturized continuous zoom lens, which solves the problems of existing floating aperture zoom lenses such as rapid changes in image brightness throughout the zoom range, high requirements for optical machine parts processing, large aperture of the front fixed group, non-compact structure, great design difficulty, and inability to achieve miniaturization. The design method of the present invention selects a positive group compensating zoom optical path structure with miniaturization potential, and the aperture diaphragm is located on the compensating group or the intermediate fixed group. Unlike the traditional positive group compensating aperture floating zoom lens, the zoom lens designed by the present invention is different in that during the zoom process, the incident light beam fills the aperture diaphragm in any field of view within a preset focal length range, and the aperture of the optical system at each focal length position can be kept constant, thereby overcoming the shortcomings of the traditional positive group compensating aperture floating zoom lens, and the resulting continuous zoom lens has the advantages of a more compact structure and appearance, low cost, miniaturization, and excellent imaging.

Description

Technical Field

[0001] The present invention relates to an optical imaging system and a design method thereof, and in particular to a miniaturized continuous zoom lens and a design method thereof. Background Art

[0002] Zoom lenses are widely used in navigation, search, tracking, and reconnaissance. Traditional fixed-focus lenses have a fixed focal length, limiting the ability to observe targets within a specific field of view, making them difficult to search and observe. Continuous zoom lenses, on the other hand, offer a continuously variable focal length. Short focal lengths with a large field of view allow for wide-area searches, increasing the probability of target capture. Long focal lengths with a narrow field of view allow for identification and tracking of detected targets. Continuous zoom systems are typically installed in electro-optical domes or pods, where limited space necessitates a compact and lightweight system.

[0003] Traditional zoom lenses often use optical system aperture floating (F-number change) to achieve miniaturization. The aperture diaphragm needs to be set between the moving components so that the optical system aperture can change during the magnification process. The focusing group is located in the front fixed group. The floating aperture design means that the short-focus zoom lens often has a larger aperture than the long-focus one, which increases the difficulty of optical design on the one hand; on the other hand, in infrared systems, non-uniformity correction is usually required, and the illumination of the detector target surface is different at different apertures, which increases the burden of non-uniformity correction; secondly, the larger aperture at short focus may cause the image brightness of the zoom lens to change dramatically throughout the zoom range, and the image may be saturated at short focus; in addition, the different apertures of long and short focus result in different focal depths of the long and short focus optical systems. If the focusing group is placed in the rear fixed group to reduce the overall size, the zoom lens may have poor image consistency throughout the zoom range due to errors in the later assembly, which not only places high requirements on the processing accuracy of optical and mechanical parts, but also increases the cost. At the same time, the floating aperture requires the focusing group to be located in the front fixed group of the zoom lens. Due to the presence of components such as the focusing structure and focusing motor, the overall size of the lens front end will be greatly increased.

[0004] Placing the aperture diaphragm in the fixed rear group of a zoom lens can achieve a constant aperture, resolving the aforementioned issues. The focusing group can also be placed at the rear. However, this type of zoom lens generally has larger dimensions than a floating aperture zoom lens. For example, in a cooled infrared zoom lens, the detector cold stop serves as the optical system aperture diaphragm. Using a secondary or multiple imaging system, the zoom system is long and requires many lenses. This structure is widely used in the medium-wave band. For visible or long-wave infrared zoom lenses, using a multiple imaging optical path results in excessive system size and a less compact design. In a single imaging optical path, to achieve a fixed aperture, the aperture diaphragm is typically located in the fixed rear group of the zoom lens. This results in a larger diameter for the fixed front group of lenses. Due to the limitations of the zoom structure, zoom lenses with this structure are generally larger than floating aperture zoom lenses, hindering miniaturization. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of existing floating aperture zoom lenses such as rapid changes in image brightness during zooming, high requirements for the processing of optical and mechanical parts, large aperture of the front fixed group, non-compact structure, great design difficulty, and inability to be miniaturized, and to provide a miniaturized continuous zoom lens and a design method thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for designing a miniaturized continuous zoom lens is characterized in that it includes the following steps:

[0008] Step 1. Select the initial structure of the zoom lens

[0009] An optical path structure with the potential for miniaturized zooming is selected as the initial structure of the zoom lens; the optical path structure is a primary imaging optical path structure with a positive group compensating floating aperture, comprising a front fixed group, a zoom group, a compensating assembly, and a rear fixed group arranged in sequence along the optical axis; and also comprising an aperture stop, which is located in the compensating assembly;

[0010] Step 2: Control the height of the light at the edge of the field of view at each focal length on the aperture stop surface

[0011] In the optical design software, the basic parameters of the initial structure of the zoom lens are adjusted to control the height of the marginal light of the incident light beam at different fields of view at each focal length position on the aperture stop surface, so that the marginal light of the on-axis and off-axis fields of view at different focal length positions at the same F number fills the aperture stop diameter; the F number of the zoom lens remains constant at each focal length position throughout the zoom range;

[0012] Step 3: Determine whether the height of the light at the edge of the field of view at each focal length position meets the requirements on the aperture stop surface

[0013] Calculate the height of the light at the edge of the field of view at each focal length position on the aperture stop surface, and determine whether the deviation between the height and the semi-diameter of the aperture stop is less than a preset threshold. If so, proceed to step 4; otherwise, return to step 2 and readjust the basic parameters of the initial structure of the zoom lens.

[0014] Step 4: Zoom lens pupil aberration control

[0015] Constrain the height of the off-axis maximum field of view beam at the telephoto position on the front fixed group to determine whether the light aperture of the front fixed group meets the preset requirements. If so, proceed to step 5; otherwise, return to step 2 and readjust the basic parameters of the initial structure of the zoom lens.

[0016] Step 5: Optimize image quality

[0017] Evaluate the image quality at each focal length of the zoom lens. If the image quality meets the requirements, the design of the miniaturized continuous zoom lens is completed. Otherwise, return to step 2 and readjust the basic parameters of the initial structure of the zoom lens.

[0018] Furthermore, in step 1, the compensation component is a compensation group, and the aperture stop is located in the compensation group and changes position as the compensation group moves.

[0019] Furthermore, in step 1, the compensation assembly includes a compensation group and an intermediate fixing group;

[0020] The compensation group is arranged on the optical axis behind the zoom group, and an intermediate fixed group is arranged between the two moving groups of the zoom group and the compensation group; the aperture diaphragm is located in the intermediate fixed group, and the position of the aperture diaphragm remains unchanged during the zoom process.

[0021] Furthermore, in step 2, when the front fixed group, the zoom group, the compensation group, and the rear fixed group contain aspheric lenses or diffractive lenses, the number of fields of view at each focal length position is ≥4.

[0022] Furthermore, in step 3, the preset threshold is 2% of the semi-diameter of the aperture stop.

[0023] Furthermore, in step 4, the preset requirement is that the ratio of the maximum clear aperture of the front fixed group to the entrance pupil diameter of the optical system at the telephoto position is 1-1.3.

[0024] Furthermore, in step 5, the imaging quality of each focal length position of the zoom lens is evaluated using the optical transfer function MTF or wavefront aberration.

[0025] Furthermore, in step 2, the optical design software is CODEV or ZEMAX.

[0026] Furthermore, in step 2, the basic parameters of the initial structure of the zoom lens are adjusted by adjusting the curvature radius, optical material, lens spacing, lens thickness, number of lenses and surface parameters of the front fixed group, the zoom group, the compensation group and the rear fixed group.

[0027] A miniaturized continuous zoom lens, which is special in that it includes a front fixed group, a zoom group 2, a compensation group, and a rear fixed group arranged in sequence along the optical axis; its optical parameters are as follows:

[0028] The front fixed group includes a first lens made of Ge; the front surface of the first lens is spherical, with a radius of curvature of 141.061 mm and a center thickness of 10.731 mm; the rear surface of the first lens is an even aspheric surface, with a radius of curvature of 285.961 mm, and the center distance from the zoom group is Z1. The even aspheric coefficients are A4=1.4678519e-008, A6=-1.1068265e-013, and A8=2.2172281e-017;

[0029] The zoom group includes a second lens made of Ge and having a center thickness of 2 mm; the front surface of the second lens is an even aspheric surface with a curvature radius of -148.618 mm, and the even aspheric coefficients are A4=9.9826539e-007 and A6=-1.5097001e-010; the rear surface of the second lens is a spherical surface with a curvature radius of 134.592 mm, and the center distance from the compensation assembly is Z2;

[0030] The compensation assembly is a compensation group, including a third lens and a fourth lens. The third lens is made of Ge, has a center thickness of 2.971 mm, a front surface that is an even aspheric surface, and is provided with an aperture stop. The radius of curvature is 117.543 mm, and the even aspheric coefficients are A4=-1.4823481e-007, A6=-5.9830651e-011, and A8=6.8977705e-014. The rear surface of the third lens is spherical, with a radius of curvature of 359.052 mm, and the center spacing from the fourth lens is 0.227 mm. The fourth lens is made of ZnSe, has a center thickness of 2 mm, a front surface that is spherical, and a radius of curvature of 133.292 mm. The rear surface of the fourth lens is spherical, with a radius of curvature of 81.128 mm, and the center spacing from the rear fixed group is Z3.

[0031] The rear fixed group includes a fifth lens and a sixth lens. The material of the fifth lens is IRG207, the center thickness is 4mm, the front surface is spherical, and the radius of curvature is 63.019mm. The rear surface of the fifth lens is an even aspheric surface with a radius of curvature of 136.049mm. The even aspheric coefficients are A4=1.3895618e-007, A6=-9.9224337e-011, and A8=1.0038968e-013. The center spacing of the fifth lens and the sixth lens is 1.3895618e-007, A6=-9.9224337e-011, and A8=1.0038968e-013. The sixth lens is made of Ge, has a center thickness of 2.556 mm, an even aspheric front surface with a radius of curvature of 27.654 mm, and even aspheric coefficients of A4 = -1.8862382e-006, A6 = -5.3959853e-009, and A8 = -2.6492025e-011. The rear surface of the sixth lens is a spherical surface with a radius of curvature of 31.721 mm and is spaced 10.954 mm from the center of the image plane.

[0032] The range of Z1 is 6.39mm~46.78mm~51.56mm;

[0033] The range of Z2 is 62.59mm~28.77mm~1mm;

[0034] The Z3 variation range is 7.575mm~1mm~23.99mm.

[0035] Beneficial effects of the present invention:

[0036] (1) The present invention provides a miniaturized continuous zoom lens and a design method thereof, wherein a positive group compensating zoom optical path structure with miniaturization potential is selected, and an aperture diaphragm is located on the compensating group or the intermediate fixed group. Unlike a conventional positive group compensating aperture floating zoom lens, the zoom lens designed by the present invention is configured such that during the zooming process, the incident light beam fills the aperture diaphragm in any field of view within a preset focal length range, thereby enabling the aperture of the optical system to remain constant at each focal length position, thereby overcoming the shortcomings of conventional positive group compensating aperture floating zoom lenses. The resulting continuous zoom lens has the advantages of a more compact structure, low cost, miniaturization, and excellent imaging.

[0037] (2) The present invention provides a miniaturized continuous zoom lens and its design method, which overcomes the disadvantage of conventional floating aperture zoom lenses, where only the front fixed group can be used as the focusing group, resulting in a larger front fixed group. Furthermore, the design further reduces the aperture of the front fixed group by controlling pupil aberration.

[0038] (3) The present invention provides a miniaturized continuous zoom lens and a design method thereof. The zoom lens has a constant aperture, which is also helpful in reducing the difficulty of zoom lens design and has universal applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flow chart of a first embodiment of a method for designing a miniaturized continuous zoom lens according to the present invention;

[0040] Figure 2 This is a schematic diagram of the initial structure of the zoom lens in Embodiment 1 of a method for designing a miniaturized continuous zoom lens according to the present invention;

[0041] Figure 3 This is a schematic diagram of the optical path structure of the uncooled long-wave infrared continuous zoom system at a short focal length of 20 mm designed in Example 2 of a miniaturized continuous zoom lens of the present invention;

[0042] Figure 4 This is a schematic diagram of the optical path structure of the uncooled long-wave infrared continuous zoom system at a medium focal length of 85 mm designed in Example 2 of a miniaturized continuous zoom lens of the present invention;

[0043] Figure 5 This is a schematic diagram of the optical path structure of the uncooled long-wave infrared continuous zoom system at a telephoto focal length of 140 mm designed in Example 2 of a miniaturized continuous zoom lens of the present invention;

[0044] Figure 6 This is an optical transfer function diagram of the uncooled long-wave infrared continuous zoom system designed in Example 2 of a miniaturized continuous zoom lens of the present invention at a short focal length of 20 mm;

[0045] Figure 7 This is an optical transfer function diagram of an uncooled long-wave infrared continuous zoom system designed in Example 2 of a miniaturized continuous zoom lens of the present invention at a medium focal length of 85mm;

[0046] Figure 8 This is an optical transfer function diagram of the uncooled long-wave infrared continuous zoom system designed in Example 2 of a miniaturized continuous zoom lens of the present invention at a telephoto focal length of 140 mm.

[0047] In the figure, 1-front fixation group; 2-zoom group; 3-compensation group; 4-back fixation group. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the accompanying drawings and embodiments. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] Example 1

[0050] A design method for a miniaturized continuous zoom lens, such as Figure 1As shown, the following steps are included:

[0051] Step 1. Select the initial structure of the zoom lens

[0052] The selection of zoom lens structure is crucial to achieving miniaturization. In this embodiment, an optical path structure with miniaturized zoom potential is selected as the initial structure of the zoom lens; wherein the optical path structure is a primary imaging optical path structure with a positive group compensation floating aperture, such as Figure 2 As shown, the optical system includes a front fixed group 1, a zoom group 2, a compensation group 3, and a rear fixed group 4, which are sequentially arranged along the optical axis. Both the zoom group 2 and the compensation group 3 are movable groups, and an intermediate fixed group can be provided between the two movable groups. The optical system also includes an aperture stop, which is located in either the compensation group 3 or the intermediate fixed group. When the aperture stop is located in the intermediate fixed group, its position remains unchanged during zooming. When the aperture stop is located in the compensation group 3, its position changes with the movement of the compensation group 3. In this embodiment, the diameter of the aperture stop remains unchanged.

[0053] Step 2: Control the height of the light at the edge of the field of view at each focal length on the aperture stop surface

[0054] In the optical design software CODEV or ZEMAX, while meeting the basic design index requirements of the zoom lens (such as focal length and F-number), adjust the basic parameters of the initial structure of the zoom lens, that is, adjust the curvature radius, optical material, lens spacing, lens thickness, number of lenses and surface parameters of the front fixed group 1, magnification group 2, compensation group 3 and rear fixed group 4, control the height of the edge light of the incident light beam in different fields of view at each focal length position on the aperture stop surface, so that the on-axis and off-axis edge light of the field of view at different focal length positions at the same F-number fills the aperture stop, and the F-number of each focal length position of the zoom lens remains constant throughout the zoom range.

[0055] In this embodiment, the aperture of the aperture stop at the telephoto position is used as a reference to control the aperture of the light beam incident on the aperture stop at other zoom positions; the F number of the zoom lens remains consistent at all focal length positions throughout the zoom range.

[0056] When the front fixed group 1, the zoom group 2, the compensation group 3, and the rear fixed group 4 include aspheric lenses or diffractive lenses, in step 2, during the process of controlling the heights of the marginal rays of the incident light beams of multiple fields of view at each focal length position on the aperture stop surface, the number of fields of view at each focal length position must be ≥ 4. The marginal rays of the on-axis fields of view at different focal length positions fill the aperture stop diameter, while the marginal rays of the off-axis fields of view fill the aperture stop diameter. During this process, the aperture stop diameter remains constant.

[0057] Step 3: Determine whether the height of the light at the edge of the field of view at each focal length position meets the requirements on the aperture stop surface

[0058] Calculate the height of the light at the edge of the field of view at each focal length on the aperture stop surface, and determine whether the deviation between this height and the semi-diameter of the aperture stop is within 2% of the semi-diameter of the aperture stop. If so, proceed to step 4; otherwise, return to step 2 and readjust the basic parameters of the initial structure of the zoom lens.

[0059] Step 4: Zoom lens pupil aberration control

[0060] First, the maximum clear aperture of the optical system's front fixed group in the short-focus position is smaller than that of the optical system's front fixed group in the long-focus position. In other words, the maximum clear aperture of the front fixed group is determined by the height of the optical system's maximum field of view beam in the long-focus position. Using the software's built-in macros in the optical design software, constrain the height of the telephoto position's off-axis maximum field of view beam at the front fixed group 1. By constraining the height of the off-axis maximum field of view beam at the front fixed group, we can prevent excessive pupil aberration from causing the front fixed group lens to oversize.

[0061] Secondly, determine whether the ratio of the maximum clear aperture of the front fixed group 1 to the entrance pupil diameter of the optical system at the telephoto position is 1 to 1.3. If so, execute step 5; otherwise, return to step 2 and readjust the basic parameters of the initial structure of the zoom lens.

[0062] The maximum light aperture of the front fixed group 1 is as close as possible to the entrance pupil diameter of the optical system at the telephoto position, and preferably, the maximum light aperture of the front fixed group 1 is equal to the entrance pupil diameter of the optical system at the telephoto position.

[0063] Step 5: Optimize image quality

[0064] The imaging quality of each focal length of the zoom lens is evaluated using the optical transfer function (MTF) or wavefront aberration. If the image quality requirements are met, the design of the miniaturized continuous zoom lens is completed. Otherwise, return to step 2 to readjust the basic parameters of the initial structure of the zoom lens.

[0065] Example 2

[0066] An infrared continuous zoom lens is designed using a miniaturized continuous zoom lens design method according to this embodiment. The operating band is 8um to 12um. The basic design index requirements of the zoom lens are: the focal length of the infrared zoom lens is 20mm to 140mm, the aperture (F number) is constant at 1.4, the number of pixels of the uncooled detector is 640×512, and the pixel size is 17um×17um.

[0067] The infrared zoom lens consists of a front fixed group 1, a zoom group 2, a compensation group 3 and a rear fixed group 4. The aperture diaphragm is connected to the side of the compensation group 3 close to the zoom group 2, and the aperture diaphragm diameter remains constant. The rear fixed group 4 serves as a focusing group, and the image plane is located on the side of the rear fixed group 4 away from the compensation group 3.

[0068] In this embodiment, the initial structure of the zoom lens adopts a positive group compensation method. The zoom group 2 realizes focal length zooming, the compensation group 3 performs motion compensation to keep the image plane position fixed, and the rear fixed group 4 is used to correct residual aberrations to ensure the imaging quality of each focal length of the zoom system.

[0069] During the optimization process, CODEV optical software was used to control the height difference between the short-focus position (focal length 20mm) on the aperture stop and the long-focus position on the aperture stop, so that the height difference is ≤0.2mm. Figure 3 As shown; Figure 4 and Figure 5 As shown, the height difference between the on-axis field edge light at the mid-focus position (focal length 85mm) and the on-axis field edge light at the telephoto position (focal length 140mm) on the aperture stop is controlled to be ≤0.2mm. The system aperture stop diameter is 36.6mm. In this embodiment, the aperture stop size is determined by the on-axis field edge light at the telephoto position. The F-number at each focal length position of the zoom lens is 1.4.

[0070] This embodiment also provides a miniaturized continuous zoom lens, wherein the optical parameters of the front fixed group 1, the zoom group 2, the compensation group 3, and the rear fixed group 4 are as follows:

[0071] Table 1

[0072]

[0073] In Table 1, * indicates the position of the aperture stop.

[0074] The three zoom positions correspond to focal lengths of 20mm, 85mm, and 140mm, respectively. Among the three intervals, the Z1 range is 6.39mm to 46.78mm to 51.56mm, the Z2 range is 62.59mm to 28.77mm to 1mm, and the Z3 range is 7.575mm to 1mm to 23.99mm.

[0075] Pupil aberration control is achieved by controlling the semi-aperture of the light at the edge of the maximum field of view at the telephoto position on the front fixed group 1 in the CODEV optical software. This semi-aperture should be larger than the semi-aperture of the light at the edge of the maximum field of view at the short focal position on the front fixed group 1. The semi-aperture of the light at the edge of the maximum field of view at the telephoto position on the front fixed group 1 determines the maximum aperture of the front fixed group 1. In order to minimize the maximum clear aperture of the front fixed group 1, the semi-aperture of the light at the edge of the maximum field of view at the telephoto position on the front fixed group 1 is constrained to be as close to the entrance pupil diameter as possible.

[0076] In this embodiment, the clear aperture of the front fixed group 1 in the short focus position is 42mm, and the clear aperture of the front fixed group 1 in the long focus position is 125mm. The zoom lens has a long focus entrance pupil diameter of 100mm, while the clear aperture of the front fixed group 1 is only 125mm. The aperture stop diameter is 36.6mm, and the total lens length is 149.05mm.

[0077] The optical transfer function MTF or wave aberration is used to evaluate the imaging quality of each focal length position of the zoom lens obtained in step 4. The optical transfer function of the designed uncooled long-wave infrared continuous zoom system at a short focal length of 20mm is shown in the figure below. Figure 6 As shown in the figure, the optical transfer function of the designed uncooled long-wave infrared continuous zoom system at the middle focal length of 85mm is shown in the figure Figure 7 As shown in the figure, the optical transfer function of the designed uncooled long-wave infrared continuous zoom system at a telephoto focal length of 140mm is shown in the figure Figure 8 As shown, according to Figure 6 、 Figure 7 as well as Figure 8 It can be seen that the uncooled long-wave infrared continuous zoom system designed in this embodiment reaches or approaches the diffraction limit. Furthermore, it can be seen that the uncooled long-wave infrared continuous zoom system designed by the miniaturized continuous zoom lens design method of the present invention has high imaging quality during the zoom process.

[0078] The above description is merely a specific embodiment of the present invention, and a comparison of the effects of the specific embodiment with the relevant comparative examples. However, the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention shall be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope of protection of the claims.

Claims

1. A method for designing a miniaturized continuous zoom lens, characterized in that: The following steps are involved: Step 1. Select the initial structure of the zoom lens An optical path structure with miniaturized zoom potential is selected as the initial structure of the zoom lens; wherein the optical path structure is a one-shot imaging optical path structure with a positive group compensating floating aperture, comprising a front fixed group (1), a zoom group (2), a compensation component, and a rear fixed group (4) arranged in sequence along the optical axis; and further comprising an aperture stop, which is located in the compensation component; Step 2: Control the height of the light at the edge of the field of view at each focal length on the aperture stop surface In the optical design software, the basic parameters of the initial structure of the zoom lens are adjusted to control the height of the marginal light of the incident light beam at different fields of view at each focal length position on the aperture stop surface, so that the marginal light of the on-axis and off-axis fields of view at different focal length positions at the same F number fills the aperture stop; Step 3: Determine whether the height of the light at the edge of the field of view at each focal length position meets the requirements on the aperture stop surface Calculate the height of the light at the edge of the field of view at each focal length position on the aperture stop surface, and determine whether the deviation between the height and the semi-diameter of the aperture stop is less than a preset threshold. If so, proceed to step 4; otherwise, return to step 2 and readjust the basic parameters of the initial structure of the zoom lens. Step 4: Zoom lens pupil aberration control Constrain the height of the maximum field of view beam outside the long focus position on the front fixed group (1), and determine whether the light aperture of the front fixed group (1) meets the preset requirements. If yes, execute step 5, otherwise return to step 2 and readjust the basic parameters of the initial structure of the zoom lens; Step 5: Optimize image quality Evaluate the image quality at each focal length of the zoom lens. If the image quality meets the requirements, the design of the miniaturized continuous zoom lens is completed. Otherwise, return to step 2 and readjust the basic parameters of the initial structure of the zoom lens.

2. The method for designing a miniaturized continuous zoom lens according to claim 1, wherein: In step 1, the compensation component is a compensation group (3), and the aperture stop is located in the compensation group (3) and changes position as the compensation group (3) moves.

3. The method for designing a miniaturized continuous zoom lens according to claim 1, wherein: In step 1, the compensation assembly includes a compensation group (3) and an intermediate fixing group; The compensation group (3) is arranged on the optical axis behind the zoom group (2), and an intermediate fixed group is arranged between the two moving groups of the zoom group (2) and the compensation group (3); the aperture diaphragm is located in the intermediate fixed group, and the position of the aperture diaphragm remains unchanged during the zoom process.

4. The method for designing a miniaturized continuous zoom lens according to claim 2 or 3, wherein: In step 2, when the front fixed group (1), the zoom group (2), the compensation group (3) and the rear fixed group (4) contain aspheric lenses or diffractive lenses, the number of fields of view at each focal length position is ≥4.

5. The method for designing a miniaturized continuous zoom lens according to claim 1, wherein: In step 3, the preset threshold is 2% of the semi-diameter of the aperture stop.

6. The method for designing a miniaturized continuous zoom lens according to claim 1, wherein: In step 4, the preset requirement is that the ratio of the maximum aperture of the front fixed group (1) to the entrance pupil diameter of the optical system at the telephoto position is 1 to 1.

3.

7. The method for designing a miniaturized continuous zoom lens according to claim 1, wherein: In step 5, the imaging quality of each focal length position of the zoom lens is evaluated using the optical transfer function MTF or wave aberration.

8. The method for designing a miniaturized continuous zoom lens according to claim 1, wherein: In step 2, the optical design software is CODEV or ZEMAX.

9. The method for designing a miniaturized continuous zoom lens according to claim 2 or 3, wherein: In step 2, the basic parameters of the initial structure of the zoom lens are adjusted specifically by adjusting the curvature radius, optical material, lens spacing, lens thickness, number of lenses and surface parameters of the front fixed group (1), the zoom group (2), the compensation group (3) and the rear fixed group (4).

10. A miniaturized continuous zoom lens, characterized by: It comprises a front fixed group (1), a zoom group 2, a compensation group (3) and a rear fixed group (4) arranged in sequence along the optical axis; its optical parameters are as follows: The front fixed group (1) includes a first lens, the material of which is Ge; the front surface of the first lens is a spherical surface, the radius of curvature is 141.061 mm, and the center thickness is 10.731 mm; the back surface of the first lens is an even aspheric surface, the radius of curvature is 285.961 mm, the center distance between the first lens and the zoom group (2) is Z1, and the even aspheric coefficients are A4=1.4678519e-008, A6=-1.1068265e-013, and A8=2.2172281e-017; The zoom group (2) includes a second lens, made of Ge, with a center thickness of 2 mm; the front surface of the second lens is an even aspheric surface, with a curvature radius of -148.618 mm, and even aspheric coefficients of A4=9.9826539e-007 and A6=-1.5097001e-010; the rear surface of the second lens is a spherical surface, with a curvature radius of 134.592 mm, and the center distance from the compensation component is Z2; The compensation component is a compensation group (3), comprising a third lens and a fourth lens, wherein the third lens is made of Ge, has a center thickness of 2.971 mm, a front surface of an even aspheric surface, and is provided with an aperture stop, a curvature radius of 117.543 mm, and even aspheric coefficients of A4=-1.4823481e-007, A6=-5.9830651e-011, and A8=6.8977705e-014; the rear surface of the third lens is a spherical surface, has a curvature radius of 359.052 mm, and is spaced 0.227 mm from the center of the fourth lens; the fourth lens is made of ZnSe, has a center thickness of 2 mm, a front surface of a spherical surface, and a curvature radius of 133.292 mm; the rear surface of the fourth lens is a spherical surface, has a curvature radius of 81.128 mm, and is spaced Z3 from the center of the rear fixed group (4); The rear fixed group (4) includes a fifth lens and a sixth lens. The material of the fifth lens is IRG207, the center thickness is 4 mm, the front surface is spherical, and the radius of curvature is 63.019 mm. The rear surface of the fifth lens is an even aspheric surface, the radius of curvature is 136.049 mm, and the even aspheric coefficients are A4=1.3895618e-007, A6=-9.9224337e-011, and A8=1.0038968e-013. The distance between the fifth lens and the center of the sixth lens is 1.3895618e-007, A6=-9.9224337e-011, and A8=1.0038968e-013. The sixth lens is made of Ge, has a center thickness of 2.556 mm, a front surface that is an even aspheric surface with a radius of curvature of 27.654 mm, and even aspheric coefficients of A4 = -1.8862382e-006, A6 = -5.3959853e-009, and A8 = -2.6492025e-011. The rear surface of the sixth lens is a spherical surface with a radius of curvature of 31.721 mm and a center distance of 10.954 mm from the image plane. The range of Z1 is 6.39mm~46.78mm~51.56mm; The range of Z2 is 62.59mm~28.77mm~1mm; The Z3 variation range is 7.575mm~1mm~23.99mm.

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