Design method of deformable optical system

Abstract

The invention relates to the technical field of optical design, in particular to a design method of a deformable optical system, which comprises the following steps of: calculating focal lengths of the deformable optical system on an XOZ plane and a YOZ plane respectively according to a deformation ratio of the deformable optical system, and selecting a combination form of lenses as a combination of a rotational symmetric lens and a double-conical-surface lens; the method comprises the following steps: designing a double-conical-surface lens in a lens combination, determining the position of the double-conical-surface lens in the lens combination, designing a first optical subsystem on an XOZ plane and a second optical subsystem on a YOZ plane respectively, combining the first optical subsystem and the second optical subsystem to obtain a deformed optical system, and performing system optimization on the deformed optical system to obtain a final deformed optical system. The deformable optical system designed by the invention has the advantages of high optimization degree of freedom, strong aberration correction capability, no additional lens, light structure and space saving.

Description

Technical Field

[0001] The present invention relates to the technical field of optical design, and in particular provides a design method for an anamorphic optical system. Background Art

[0002] Optical systems can be divided into rotationally symmetric optical systems, biplane symmetric optical systems, and single-plane symmetric optical systems based on their symmetry. Biplane symmetric optical systems are symmetrical in both the XOZ and YOZ planes, and the vertical magnifications on the two symmetry planes can be designed to be different. Therefore, this type of optical system can form unique distorted images, and is therefore also called an anamorphic optical system. The image distortion ratio is the ratio of the vertical magnifications in the two symmetry planes of the optical system.

[0003] The imaging properties of anamorphic optical systems offer unique advantages in specific applications. Anamorphic optical systems can effectively increase the field of view (FOV) within a specific direction, expanding the imaging range without increasing the sensor area or changing the sensor ratio. For example, anamorphic lenses are widely used in the film and television industry, enabling them to capture 16:9 widescreen scenes on a 4:3 camera sensor.

[0004] Nowadays, optical systems are developing in the direction of miniaturization and lightweight, and are more often carried on small platforms such as mobile phones, sports cameras, and small civilian photography drones. Compared with interchangeable lens cameras, mobile phones, sports cameras, and small civilian photography drones have higher requirements for the miniaturization of cameras and the lightness of weight. The design configuration of existing anamorphic optical systems is mostly to add an afocal anamorphic attachment on the basis of a conventional optical system. The afocal anamorphic attachment consists of two cylindrical lenses, which are usually placed in front of the optical system (common configuration for fixed-focus anamorphic systems), behind (common configuration for zoom optical systems), or in the middle (no essential difference from the above two configurations). The above design method results in the anamorphic optical system being too large and too heavy. When using cylindrical lenses to design an anamorphic optical system, according to the sagittal height equation of the cylindrical lens: .

[0005] in, Indicates Yagao, It represents the horizontal distance from the lens vertex (or reference point) in a plane perpendicular to the optical axis and parallel to the direction of expansion of the cylindrical surface of the cylindrical lens. Represents the radius of curvature. From the above sag equation, we can see that there is only one parameter in the cylindrical lens. Variable, resulting in low utilization of element design freedom and the need to correct more aberrations. Summary of the Invention

[0006] To solve the above problems, the present invention provides a design method for an anamorphic optical system, which adopts a biconical lens instead of a cylindrical lens and utilizes the multi-focal power characteristics of the biconical lens to improve the aberration correction capability. No additional lenses are required, and the structure is compact and small.

[0007] The design method of the anamorphic optical system provided by the present invention includes: S1: Calculate the focal length of the anamorphic optical system on the XOZ plane and the YOZ plane according to the deformation ratio of the anamorphic optical system; S2: Selecting a lens combination of an anamorphic optical system, the lens combination including a rotationally symmetric lens and a biconical lens; determining the position of the biconical lens in the lens combination; S3: Designing the first optical subsystem on the XOZ plane and the second optical subsystem on the YOZ plane based on the lens combination and the focal lengths of the anamorphic optical system on the XOZ plane and the YOZ plane, respectively; and calculating in real time the third-order aberration coefficients of the anamorphic optical system formed by combining the first optical subsystem and the second optical subsystem. S4: combining the first optical subsystem and the second optical subsystem to obtain an anamorphic optical system; S5: Perform system optimization on the anamorphic optical system.

[0008] Preferably, all optical elements of the first optical subsystem and the second optical subsystem are rotationally symmetric lenses.

[0009] Preferably, the first optical subsystem and the second optical subsystem have exactly the same number of optical elements, lens spatial positions, lens thicknesses, and distances between lenses.

[0010] Preferably, in the first optical subsystem and the second optical subsystem, the curvature radii of the lenses corresponding to the biconical lenses of the anamorphic optical system are different.

[0011] Preferably, in the first optical subsystem and the second optical subsystem, the surface parameters of the lenses corresponding to the rotationally symmetric lenses of the anamorphic optical system are the same.

[0012] Preferably, the method for calculating the third-order aberration coefficient is: tracing the main ray data and marginal ray data of the first optical subsystem and the second optical subsystem, combining the surface parameters of the first optical subsystem and the second optical subsystem, establishing an analytical expression for the third-order aberration coefficient, and calculating the third-order aberration coefficient of the anamorphic optical system.

[0013] Preferably, the method for establishing the analytical expression of the third-order aberration coefficient is: establishing the aberration contribution model of the first optical subsystem and the second optical subsystem, analyzing the correlation between the main light data, the marginal light data and the surface parameters of the first optical subsystem and the second optical subsystem, and obtaining the analytical expression of the third-order aberration coefficient.

[0014] Preferably, the analytical expression of the third-order aberration coefficient is: ; in, Indicates that the light After the surface is refracted, the refractive index of the space is, The light of XOZ plane is After refraction on the surface, the tangent value of the angle between the light and the Z axis is, Denotes the anamorphic optical system The component on the Y axis of the difference between the intersection point of the paraxial ray and the intersection point of the real ray at each surface is: It represents the component on the X-axis of the difference between the intersection point of the paraxial ray and the intersection point of the real ray at the image plane of the anamorphic optical system. represents the refractive invariant of the anamorphic optical system in the YOZ plane, and Represents the edge rays of the XOZ plane and the YOZ plane and the The distance from the intersection of the two surfaces to the Z axis, and Represents the edge rays of the XOZ plane and the YOZ plane in the The tangent value of the angle between the surface and the Z axis after refraction, and Represents the surface The curvature in the X-axis direction and the curvature in the Y-axis direction, represents the Y Lagrange invariant, Indicates the distance between the principal ray of the YOZ plane and the Z axis at the intersection of the jth surface, Indicates the amount of change, and They represent the conic coefficient of surface j in the X-axis direction and the conic coefficient in the Y-axis direction, represents the normalized field of view coordinates, Indicates the The tangent value of the angle between the edge ray of the YOZ plane and the Z axis at each surface, Indicates the difference in the Y direction between the position of the aberrated ray on the system image plane and the ideal position of the ray.

[0015] Preferably, the method for merging the first optical subsystem and the second optical subsystem is: keeping the rotationally symmetric lens unchanged; using the curvature and cone coefficient of the first optical subsystem and the curvature and cone coefficient of the second optical subsystem as the curvature and cone coefficient of the biconical lens respectively.

[0016] Preferably, the method for optimizing the anamorphic optical system is to balance the low-order aberrations and high-order aberrations of the anamorphic optical system.

[0017] Compared with the prior art, the present invention can achieve the following beneficial effects: The present invention utilizes a biconical lens in the structural design of an anamorphic optical system. Compared to existing cylindrical lenses, biconical lenses possess optical power in both planes of symmetry, enabling a greater number of parameters to be optimized, a higher degree of freedom in optimization, and enhanced aberration correction capabilities, resulting in superior imaging quality. Furthermore, the biconical lens design eliminates the need for additional lenses, resulting in a compact and compact anamorphic optical system, helping to reduce system mass and overall length, saving space. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a flow chart of a method for designing an anamorphic optical system according to an embodiment of the present invention; Figure 2 2. Schematic diagram of a lens combination of an anamorphic optical system according to an embodiment of the present invention; Figure 3 is a schematic diagram of a lens combination of a first optical subsystem provided according to an embodiment of the present invention; Figure 4 is a schematic diagram of a lens combination of a second optical subsystem provided according to an embodiment of the present invention; Figure 5 2 is a schematic structural diagram of an anamorphic optical system provided in an embodiment of the present invention in an XOZ plane and a YOZ plane; Figure 6 4 is an MTF curve diagram of the imaging quality of the anamorphic optical system provided according to an embodiment of the present invention.

[0019] Reference numerals include: First lens 1, second lens 2, third lens 3, fourth lens 4, fifth lens 5, sixth lens 6, seventh lens 7, eighth lens 8, first optical subsystem 10, first subsystem first lens 11, first subsystem second lens 12, first subsystem third lens 13, first subsystem fourth lens 14, first subsystem fifth lens 15, first subsystem sixth lens 16, first subsystem seventh lens 17, first subsystem eighth lens 18, second optical subsystem 20, second subsystem first lens 21, second subsystem second lens 22, second subsystem third lens 23, second subsystem fourth lens 24, second subsystem fifth lens 25, second subsystem sixth lens 26, second subsystem seventh lens 27, second subsystem eighth lens 28. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present 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 herein are only used to explain the present invention and do not constitute a limitation to the present invention. Similar elements in different embodiments use associated similar element numbers. In the following embodiments, many detailed descriptions are intended to enable the present invention to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, or methods. In some cases, some operations related to the present invention are not shown or described in the specification. This is to avoid the core part of the present invention being overwhelmed by too much description. For those skilled in the art, it is not necessary to describe these related operations in detail. They can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0021] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other to form various implementation methods. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various orders in the description and the drawings are only for the purpose of clearly describing a certain embodiment and are not intended to be a required order, unless otherwise specified that a certain order must be followed.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" 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 the indicated technical features. Therefore, 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.

[0023] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art can understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0024] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0025] like Figure 1 As shown, an embodiment of the present invention provides a method for designing an anamorphic optical system, using a biconical lens instead of a cylindrical lens. The embodiment of the present invention is described by taking the design of a half-frame widescreen movie lens (hereinafter referred to as a movie lens) as an example, and the details are as follows: S1: Calculate the focal lengths of the anamorphic optical system on the XOZ plane and the YOZ plane based on the deformation ratio of the anamorphic optical system.

[0026] Taking a movie lens as an example, its aperture number is F1.8 and the distortion ratio is 1.33:1. The ratio of the focal length of the optical system of the movie lens on the XOZ plane to the YOZ plane is 1.33:1. The commonly used focal length of movie lenses, 35mm, is selected as the focal length on the YOZ plane. The focal length on the XOZ plane is 46.55mm. The matching sensor is a half-frame sensor, and the corresponding diagonal half-image height can be calculated as 14.06mm.

[0027] In the above parameters, the focal length on the YOZ plane is set as needed. The focal lengths of the anamorphic optical system on the XOZ and YOZ planes are calculated based on the distortion ratio of the anamorphic optical system. The distortion ratio of the anamorphic optical system is the ratio of the focal lengths on the XOZ and YOZ planes. For example, if the focal length on the XOZ plane is 50mm and the distortion ratio is 1.33, the focal length on the YOZ plane is 50 divided by 1.33, which is 37.59mm.

[0028] S2: Select the lens combination of the anamorphic optical system.

[0029] like Figure 2 As shown, the embodiment of the present invention uses an eight-lens combination to design the movie lens, namely a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7 and an eighth lens 8. The eight lenses include six rotationally symmetric lenses and two biconical lenses.

[0030] The embodiment of the present invention uses a biconical lens to replace the traditional cylindrical lens. The sag equation of the biconical lens is as follows:

[0031] in, Indicates Yagao, They represent the coordinate variables in two mutually perpendicular directions in the plane perpendicular to the optical axis, denote the curvatures of the biconical lens in the x and y directions, respectively. are the curvature radii of the biconical lens in the x and y directions, are the conic coefficients of the biconical lens in the x and y directions, respectively.

[0032] From the vector height equation, we can know that there are four variable parameters of the biconical lens, namely, the radius of curvature and the cone coefficient When designing and optimizing, the double cone surface of the double cone lens has more variable parameters than the cylindrical surface of the cylindrical lens, providing more degrees of freedom.

[0033] When designing an anamorphic optical system using a biconical lens, after determining the lens combination, it is necessary to determine the position of the biconical lens within the lens combination. This embodiment of the present invention includes two biconical lenses, namely the second lens 2 and the third lens 3. The remaining six lenses are all rotationally symmetric lenses. Furthermore, this embodiment of the present invention configures the remaining six lenses as rotationally symmetric lenses.

[0034] S3: Design the first optical subsystem 10 on the XOZ plane and the second optical subsystem 20 on the YOZ plane.

[0035] The anamorphic optical system designed in this invention has two planes of symmetry: the XOZ plane and the YOZ plane. Based on the selected lens combination and the focal lengths of the anamorphic optical system in the XOZ and YOZ planes, a first optical subsystem 10 in the XOZ plane and a second optical subsystem 20 in the YOZ plane are designed, respectively. For the cine lens designed in this embodiment of the invention, the focal length of the first optical subsystem 10 in the XOZ plane is 35 mm, and the focal length of the second optical subsystem 20 in the YOZ plane is 46.55 mm.

[0036] The anamorphic optical system is symmetrical about plane XOZ and plane YOZ. The first optical subsystem 10 and the second optical subsystem 20 are equivalent to the "projections" of the anamorphic optical system on plane XOZ and plane YOZ respectively. Figure 3 and Figure 4As shown, the lens combination form is the same as that of the anamorphic optical system. The designed first optical subsystem 10 and second optical subsystem 20 both include 8 lenses. The first optical subsystem 10 includes a first subsystem first lens 11, a first subsystem second lens 12, a first subsystem third lens 13, a first subsystem fourth lens 14, a first subsystem fifth lens 15, a first subsystem sixth lens 16, a first subsystem seventh lens 17, and a first subsystem eighth lens 18. The second optical subsystem 20 includes a second subsystem first lens 21, a second subsystem second lens 22, a second subsystem third lens 23, a second subsystem fourth lens 24, a second subsystem fifth lens 25, a second subsystem sixth lens 26, a second subsystem seventh lens 27, and a second subsystem eighth lens 28. The 8 lenses of the first optical subsystem 10 and the second optical subsystem 20 correspond one-to-one to the 8 lenses of the anamorphic optical system.

[0037] All optical elements of the first optical subsystem 10 and the second optical subsystem 20 are rotationally symmetric lenses, and the number of optical elements, lens spatial positions, lens thicknesses and distances between lenses of the first optical subsystem 10 and the second optical subsystem 20 are exactly the same.

[0038] In the first optical subsystem 10 and the second optical subsystem 20, the lenses corresponding to the biconical lenses of the anamorphic optical system have different curvature radii, i.e., the curvature radii of the second lens 12 of the first subsystem and the curvature radii of the second lens 22 of the second subsystem are different, and the curvature radii of the third lens 13 of the first subsystem and the curvature radii of the third lens 23 of the second subsystem are different. In the first optical subsystem 10 and the second optical subsystem 20, the surface parameters of the lenses corresponding to the rotationally symmetric lenses of the anamorphic optical system are the same, i.e., the surface parameters of the first lens 11 of the first subsystem and the first lens 21 of the second subsystem are the same, and the surface parameters of the fourth lens 14 of the first subsystem to the eighth lens 18 of the first subsystem are the same as the fourth lens 24 of the second subsystem to the eighth lens 28 of the second subsystem, respectively.

[0039] During the design process of the first optical subsystem 10 and the second optical subsystem 20, the "multiple structural forms" design function in the optical design software is used to simultaneously design the first optical subsystem 10 and the second optical subsystem 20. During the design process, the third-order aberration coefficients of the anamorphic optical system formed after the first optical subsystem 10 and the second optical subsystem 20 are calculated in real time. By tracing the principal ray data and the marginal ray data of the first optical subsystem 10 and the second optical subsystem 20, combining the surface parameters of the first optical subsystem 10 and the second optical subsystem 20, and establishing an analytical expression for the third-order aberration coefficient of the anamorphic optical system, the third-order aberration coefficients of the anamorphic optical system formed after the merger are calculated. The specific process is as follows: Based on the special geometric characteristics of the biconical lens, an aberration contribution model of each optical surface in the first optical subsystem 10 and the second optical subsystem 20 is established. The correlation between the main ray data, marginal ray data and the surface parameters of the first optical subsystem and the second optical subsystem is analyzed, and an analytical expression for the system-level aberration coefficient is derived.

[0040] Specifically, the embodiment of the present invention uses represents the number of optical surfaces in an anamorphic optical system. Its third-order aberration coefficient can be expressed as the linear superposition of the aberration contributions of each surface. The derivation process is as follows: , , , , , , , , , , , , , , .

[0041] in, Represents the total number of optical surfaces in the anamorphic optical system. It is the last surface of the anamorphic optical system, usually the image plane. represents any optical surface in an anamorphic optical system, represents the refractive index, Indicates the The refractive index of the space where the light is located in front of the surface, Indicates that the light The refractive index of the space after the surface is refracted, The light of XOZ plane is After refraction on the surface, the tangent value of the angle between the light and the Z axis is, Denotes the anamorphic optical system At the surface, the component on the Y axis of the difference between the intersection point of the paraxial ray and the intersection point of the real ray, It represents the component on the X-axis of the difference between the intersection point of the paraxial ray and the intersection point of the real ray at the image plane of the anamorphic optical system. Indicates the difference in the Y direction between the position of the aberrated light on the system image plane and the ideal position of the light. and They represent the refractive invariants of the principal ray of the anamorphic optical system in the XOZ plane and the YOZ plane, respectively. and Represents the edge rays of the XOZ plane and the YOZ plane and the The distance from the intersection of the two surfaces to the Z axis, and Represents the surface The curvature in the X-axis direction and the curvature in the Y-axis direction, and represent the X Lagrange invariant and the Y Lagrange invariant respectively, and Respectively represent the distances of the principal rays of the XOZ plane and the YOZ plane from the optical axis (Z axis), represents the normalized field of view coordinates, and Represents the edge rays of the XOZ plane and the YOZ plane in the The tangent value of the angle between the surface and the Z axis before refraction, and The principal rays of the XOZ plane and the YOZ plane are represented in the The tangent of the angle between the surface and the Z axis after refraction and The principal rays of the XOZ plane and the YOZ plane are represented in the The tangent value of the angle between the surface and the Z axis before refraction, and The principal rays of the XOZ plane and the YOZ plane are represented in the After the surface is refracted, the tangent value of the angle with the Z axis is, Indicates the The tangent value of the angle between the edge ray of the XOZ plane and the Z axis at each surface, Indicates the The tangent value of the angle between the edge ray of the YOZ plane and the Z axis at each surface, and Represents the surface The curvature in the X-axis and Y-axis directions, and Represents the surface Conic coefficients in the X-axis and Y-axis directions, represents the normalized pupil coordinates of the ray, Indicates the amount of change. Its specific meaning is related to the parameter that follows it, for example: Indicates that the light The difference in refractive index between a surface before and after refraction.

[0042] The above series of expressions are the expressions for the third-order aberration coefficients of the anamorphic optical system using a double-conical surface shape derived in this application. Optical design software such as ZEMAX, CodeV, GODAS, etc. can be used for ray tracing to obtain the propagation data of light in the optical system. The third-order aberration coefficients of the anamorphic optical system calculated using the above expressions can guide the optimization of the anamorphic optical system and participate in the system optimization as a constraint condition.

[0043] S4: Combining the designed first optical subsystem 10 and the second optical subsystem 20 to obtain an anamorphic optical system.

[0044] The first optical subsystem 10 and the second optical subsystem 20 have the same number of lenses, lens thicknesses, and relative positions. Except for the lens corresponding to the biconical lens, the surface parameters of the remaining lenses in the first optical subsystem 10 and the second optical subsystem 20 are completely consistent. That is, the surface parameters of the first lens 11 of the first subsystem and the first lens 21 of the second subsystem are the same, and the surface parameters of the fourth lens 14 of the first subsystem to the eighth lens 18 of the first subsystem are the same as the fourth lens 24 of the second subsystem to the eighth lens 28 of the second subsystem, respectively.

[0045] Furthermore, according to the surface parameters of the first optical subsystem 10 and the second optical subsystem 20, the first optical subsystem 10 and the second optical subsystem 20 are merged into a new optical system, and the new optical system is the anamorphic optical system to be designed. The anamorphic optical system formed by merging the remaining lenses except the biconical lens is no different from the first optical subsystem 10 and the second optical subsystem 20. In particular, for the lens whose surface is pre-set as a biconical surface, its curvature radius and cone coefficient come from the curvature radius and cone coefficient of the first subsystem second lens 12 and the first subsystem third lens 13 in the first optical subsystem 10 and the second subsystem second lens 22 and the second subsystem third lens 23 in the second optical subsystem 20, respectively. The curvature radius and the cone coefficient Coming to the first optical subsystem 10, , radius of curvature and the cone coefficient Coming to the second optical subsystem 20, All the surface parameters of the biconical lens have been determined, and further all the parameters of the anamorphic optical system are clear, and the final anamorphic optical system can be obtained.

[0046] S5: Perform system optimization on the obtained anamorphic optical system.

[0047] Because the third-order aberrations of the merged optical system have been calculated in real time in step S3 before the first optical subsystem 10 and the second optical subsystem 20 are merged in step S4, the high-order aberrations of the merged anamorphic optical system still exist. The low-order aberrations and high-order aberrations of the merged anamorphic optical system are balanced to achieve good image quality.

[0048] After the parameter design of the movie lens according to the embodiment of the present invention, the parameters of the anamorphic optical system obtained by combining the first optical subsystem 10 and the second optical subsystem 20 are shown in Table 1: Table 1 Parameters of anamorphic optical system

[0049] The parameters of the biconical lens are shown in Table 2: Table 2 Biconical lens parameters

[0050] It should be noted that the above lens surface numbers are the lens surfaces corresponding to the lens arrangement from left to right as shown in the accompanying drawings.

[0051] The aberration balance of the anamorphic optical system obtained in the above steps S1 to S5 is performed to further improve the imaging quality. Figure 5 The anamorphic optical system shown in FIG. 1 , XOZ and YOZ are two symmetry planes of the anamorphic optical system.

[0052] The cine lens of the present invention has a total lens length of less than 62mm, and a total length from the front end of the lens to the image plane of less than 76mm. The overall structure is more compact and uses eight lenses, including one set of doublets and two planar symmetrical elements. This method was used to design a catadioptric and transmissive optical system for this cine lens. The MTF graph of its imaging quality is shown below. Figure 6 As shown, it can be seen that the imaging quality is high and the effect is good. Figure 6 F1 to F7 refer to the field of view set in the optical design software for evaluating system performance. The field of view set in this system is the RIH (real image height). The horizontal axis represents spatial frequency (cycles / mm), the vertical axis represents contrast (modulation), Diff represents difference, and Limit represents limit.

[0053] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0054] The above specific embodiments of the present invention do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for designing an anamorphic optical system, characterized in that: include: S1: Calculating the focal lengths of the anamorphic optical system on the XOZ plane and the YOZ plane, respectively, based on the deformation ratio of the anamorphic optical system; S2: selecting a lens combination of the anamorphic optical system, wherein the lens combination includes a rotationally symmetric lens and a biconical lens; and determining a position of the biconical lens in the lens combination; S3: Designing a first optical subsystem on the XOZ plane and a second optical subsystem on the YOZ plane according to the lens combination and the focal length of the anamorphic optical system on the XOZ plane and the YOZ plane, respectively; calculating in real time the third-order aberration coefficients of the anamorphic optical system formed by combining the first optical subsystem and the second optical subsystem; S4: combining the first optical subsystem and the second optical subsystem to obtain an anamorphic optical system; S5: Perform system optimization on the anamorphic optical system.

2. The method for designing an anamorphic optical system according to claim 1, wherein: All optical elements of the first optical subsystem and the second optical subsystem are rotationally symmetric lenses.

3. The method for designing an anamorphic optical system according to claim 1, wherein: The first optical subsystem and the second optical subsystem are exactly the same in terms of the number of optical elements, the spatial position of lenses, the thickness of lenses and the distance between lenses.

4. The method for designing an anamorphic optical system according to claim 1, wherein: In the first optical subsystem and the second optical subsystem, the curvature radii of the lenses corresponding to the biconical lenses of the anamorphic optical system are different.

5. The method for designing an anamorphic optical system according to claim 1, wherein: In the first optical subsystem and the second optical subsystem, the surface parameters of the lenses corresponding to the rotationally symmetric lenses of the anamorphic optical system are the same.

6. The method for designing an anamorphic optical system according to claim 1, wherein: The method for calculating the third-order aberration coefficient is as follows: tracing the principal ray data and marginal ray data of the first optical subsystem and the second optical subsystem, combining the surface parameters of the first optical subsystem and the second optical subsystem, establishing an analytical expression for the third-order aberration coefficient, and calculating the third-order aberration coefficient of the anamorphic optical system.

7. The method for designing an anamorphic optical system according to claim 6, wherein: The method for establishing the analytical expression of the third-order aberration coefficient is: establishing the aberration contribution model of the first optical subsystem and the second optical subsystem, analyzing the correlation between the main light data, the marginal light data and the surface parameters of the first optical subsystem and the second optical subsystem, and obtaining the analytical expression of the third-order aberration coefficient.

8. The method for designing an anamorphic optical system according to claim 7, wherein: The analytical expression of the third-order aberration coefficient is: ； in, Indicates that the light After the surface is refracted, the refractive index of the space is, The light of XOZ plane is After refraction on the surface, the tangent value of the angle between the light and the Z axis is, Denotes the anamorphic optical system The component on the Y axis of the difference between the intersection point of the paraxial ray and the intersection point of the real ray at each surface is: It represents the component on the X-axis of the difference between the intersection point of the paraxial ray and the intersection point of the real ray at the image plane of the anamorphic optical system. represents the refractive invariant of the anamorphic optical system in the YOZ plane, and Represents the edge rays of the XOZ plane and the YOZ plane and the The distance from the intersection of the two surfaces to the Z axis, and Represents the edge rays of the XOZ plane and the YOZ plane in the The tangent value of the angle between the surface and the Z axis after refraction, and Represents the surface The curvature in the X-axis direction and the curvature in the Y-axis direction, represents the Y Lagrange invariant, Indicates the distance between the principal ray of the YOZ plane and the Z axis at the intersection of the jth surface, Indicates the amount of change, and They represent the conic coefficient of surface j in the X-axis direction and the conic coefficient in the Y-axis direction, represents the normalized field of view coordinates, Indicates the The tangent value of the angle between the edge ray of the YOZ plane and the Z axis at each surface, Indicates the difference in the Y direction between the position of the aberrated ray on the system image plane and the ideal position of the ray.

9. The method for designing an anamorphic optical system according to claim 1, wherein: The method for merging the first optical subsystem and the second optical subsystem is: keeping the rotationally symmetric lens unchanged; using the curvature, cone coefficient of the first optical subsystem and the curvature, cone coefficient of the second optical subsystem as the curvature and cone coefficient of the biconical lens respectively.

10. The method for designing an anamorphic optical system according to claim 1, wherein: The method for optimizing the anamorphic optical system is to balance the low-order aberrations and high-order aberrations of the anamorphic optical system.

Images