JP2003279853A - Design method for optical system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a design method for an optical system suitable for execution in a computer, for efficiently designing the optical system in which the performance change of the optical system by manufacture errors is suppressed in addition to the optical design of various aberrations or the like. <P>SOLUTION: In the design method for the optical system using an evaluation function, at least one evaluation item relating to the manufacture error is used as the evaluation function. The evaluation item includes a manufacture error sensitivity coefficient and the manufacture error sensitivity coefficient is indicated by the fine change of optical performance caused at the time of finely changing the component of the optical system. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system design method, and more particularly to an optical system design method suitable for execution by a design processing device such as a computer. The present invention also relates to a recording medium having an optical system design program recorded therein, and an optical system and an optical device designed by using the present optical system design method or the optical system design program.

[0002]

2. Description of the Related Art A steepest descent method, a conjugate gradient method, a least squares method and the like are used as an optical system designing method. Both methods are called optimization methods, and an evaluation function having a plurality of variables is used. When these optimization methods are used for designing an optical system, evaluation items (for example, aberration coefficients) correspond to variables of the evaluation function.

This evaluation item is the radius of curvature of the optical action surface,
It is calculated based on the values of the constituent elements of the optical system such as the surface spacing and the refractive index. Therefore, the value of the evaluation item changes when the value of the component changes, and the value of the evaluation function changes when the value of the evaluation item changes. Therefore, the values of the constituent elements are gradually changed to perform the process of obtaining the optimum value (for example, the minimum value or the minimum value) of the evaluation function. In this way, when the optimum value of the evaluation function is obtained, the combination of the values of the constituent elements at that time represents the optimum optical system. As a result, the values of the constituent elements of the optical system which are close to the ideal state can be obtained. When obtaining the optimum value of the evaluation function, the evaluation items are simultaneously brought close to the desired target value.

As described above, the design of the optical system seeks the constituent elements of the optical system such that the evaluation function becomes the optimum value and the evaluation items reach the range of the target value. As described above, when designing an optical system, it is common to use the radius of curvature of the optically active surface, the surface spacing, and the refractive index as basic variables. However, in the conventional optical system design, since the optical system was designed in an ideal state, there is a tendency for the design to ignore the influence of the manufacturing error of the optical system. Therefore, it is difficult to obtain an optimum combination (design value) of the values of the constituent elements of the optical system in consideration of the change in the performance of the optical system due to the manufacturing error.

In the conventional technology, based on the experience and knowledge of the designer, etc., the designer's own hand is calculated from the design value obtained by the computer so that the change in the performance of the optical system due to the manufacturing error is reduced. Depending on the work, some modifications may be made to the design values, or some of the optical system variables may be set to fixed values, and the number of variables may be limited to obtain the optimum optical system design values for manufacturing. I had to do it. Therefore, despite the increase in computer calculation speed, the conventional optical system design requires manpower and time,
We could not design an efficient optical system. Further, it is difficult to suppress the change in performance due to manufacturing error to a small extent and obtain the optimum design value of the optical system such that the design performance has a desired value.

In recent years, in view of the above problems, Japanese Patent Laid-Open No. 11-
30746, JP-A-11-23764, JP-A-11-223769, and Japanese Patent No. 3006611.
A new design method has been proposed in Japanese Patent Publication.

[0007]

[Patent Document 1] Japanese Patent Application Laid-Open No. 11-3074
In the method disclosed in No. 6, attention is paid to a manufacturing error called decentering of the optical group. Therefore, there is a problem that it is difficult to obtain a lens system that is not easily affected by the manufacturing error in an optical system in which the performance deterioration due to the manufacturing error other than decentering is dominant.

JP-A-11-23764, JP-A-11-
The method disclosed in No. 223769 pays attention to the performance index in an ideal state without error. Therefore, it is difficult to intuitively understand the causal relationship with the deterioration of the optical performance due to the manufacturing error, and there is a problem in terms of design efficiency.

The present invention has been made in view of the above problems, and an object thereof is to be suitable for execution by a computer, and to suppress a change in performance of an optical system due to a manufacturing error in addition to an optical design such as various aberrations. It is an object of the present invention to provide an optical system design method for efficiently designing the optical system.

[0010]

In order to achieve the above object, an optical system designing method of the present invention is an optical system designing method using an evaluation function, wherein the evaluation function is an evaluation item associated with a manufacturing error. At least one, the evaluation item includes a manufacturing error sensitivity coefficient, the manufacturing error sensitivity coefficient is represented by a minute change in optical performance that occurs when the constituent elements of the optical system is slightly changed. And

In the above design method, a process of calculating various quantities of paraxial rays in a predetermined state of the optical system,
And a step of calculating an aberration coefficient in the state, and a step of calculating a manufacturing error sensitivity coefficient from the state.

Further, in the above design method, a step of calculating a power sum of manufacturing error sensitivity coefficients from a plurality of manufacturing errors is provided, and the evaluation item includes a power sum of manufacturing error sensitivity coefficients. .

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. In the description, in this embodiment, two different optical systems are used. One is an optical system obtained when the optical design is completed. This optical system is an optical system on the assumption that the lens is manufactured and arranged as designed. This optical system is an ideal optical system because it is manufactured and arranged ideally. In addition,
In this ideal optical system, each aberration is small in a balanced manner, but it is not zero.

The other is an optical system in which a lens is actually manufactured based on an ideal optical system and the lens is held by a holding member. Since the lens is mounted, this optical system is referred to as a mounting optical system. In mounting optics,
The lens is not manufactured according to design values, and is not ideally placed. Therefore, an aberration different from that of the ideal optical system occurs in the mounting optical system.

The reason why the mounting optical system produces an aberration different from that of the ideal optical system is that the mounting optical system includes a manufacturing error. Here, there are two possible manufacturing errors. One is an error in the lens itself, which is a difference between the lens in the design stage and the lens in the actually manufactured stage. The other is the error in the entire lens system, which is the position of the lens at the design stage,
This is the difference between the position of the lens and the position where the lens is actually held by the holding member. Thus, manufacturing error is one of the factors that make it difficult to obtain ideal optical system performance.

Based on the above points, in the present invention, a new evaluation item called "manufacturing error sensitivity coefficient" is used in addition to the manufacturing error in expressing the aberration generated in the mounting optical system. By using this manufacturing error sensitivity coefficient, the aberration generated in the mounting optical system is expressed as follows.

[0017]

[Equation 1]

Next, the manufacturing error sensitivity coefficient will be described. The manufacturing error sensitivity coefficient in the present invention refers to the rate of change of aberration due to the change of each element constituting the optical system.
The types of aberration generally include Seidel's five aberrations expressed in the range of the third-order approximation, the respective aberrations expressed in the range of the fifth-order approximation, and the spherical aberration expressed in the range of the seventh-order approximation. Are known. In addition, the elements that make up the optical system have a curvature (or,
(Curvature radius), surface spacing, glass refractive index, and the like.
The method of deriving the above-mentioned aberration is "aberration theory" (written by Yoshiya Matsui,
(Published by Japan Optomechatronics Association, 1989)
Omitted because it is described in. Here, only the definition of the manufacturing error sensitivity coefficient using these quantities will be described.

In general, the lateral aberration of an optical system composed of N optical action surfaces is expressed by the following equation within the range of the third approximation.

[0020]

[Equation 2] However, I, II, III, P, and V are spherical aberration coefficient, coma aberration coefficient, astigmatism coefficient, Petzval aberration coefficient, and distortion aberration coefficient, respectively. Also, αN '
Is the converted tilt angle of the exit ray of the Nth surface. Further, R is the pupil ray height, and H is an amount represented by H = n ₁ tan Ω depending on the incident ray angle Ω and the refractive index n ₁ of the medium on the object side.

These aberrations will change due to manufacturing errors. The rate of change of the aberration caused by the manufacturing error δe is calculated by using the aberration ΔY (0 + δe _i ) when a small manufacturing error δe _i occurs in a certain manufacturing error factor e _i and the aberration ΔY (0) in the ideal state. , Is expressed as follows.

[0022]

[Equation 3]

If the manufacturing error δe is sufficiently small,
This is the partial differentiation of ΔY (0) due to the error factor e _i . Therefore, the partial expression of the aberration definition equation with the error factor e _i is expressed by the following equation.

[0024]

[Equation 4] However, C _I , C _II , C _III , C _P , and C _V are a spherical aberration error sensitivity coefficient, a coma aberration error sensitivity coefficient, an astigmatism error sensitivity coefficient, and a distortion error sensitivity coefficient in this order.

Each sensitivity coefficient is defined by the following equation.

[0026]

[Equation 5] However, abe in the formula is any of I, II, III, P, and V.

Thus, the manufacturing error coefficient relating to the third-order aberration can be calculated as described above. 3
It goes without saying that the manufacturing error sensitivity coefficient can be similarly obtained for higher-order aberrations of the next and higher orders. In addition to the above analytically obtained method, a solution can be approximately obtained by numerical differentiation using a computer or the like.

Next, a method of designing the optical system according to the embodiment of the present invention will be described. The evaluation function f in the embodiment of the present invention is represented by the following formula.

[0029]

[Equation 6] However, f _o is an evaluation function in the ideal optical system (conventional evaluation function). Further, f _err is an evaluation function having at least one manufacturing error sensitivity coefficient as an evaluation item among the manufacturing error sensitivity coefficients.

[0030] can be taken into account in such an evaluation By using the function f, design change component of conventional evaluation function f _o optical performance caused by manufacturing error in not considered.
Therefore, it is possible to obtain the optimum design value of the optical system in which the deterioration of the performance of the optical system caused by the manufacturing error is suppressed and the ray aberration is small in the ideal state without the manufacturing error.

Further, it is preferable that f _err has a sum of powers of absolute values of manufacturing error sensitivity coefficients as an evaluation item.
By using such an evaluation function, it is possible to reduce the absolute value of the manufacturing error sensitivity coefficient even if there is a component having a large absolute value of the manufacturing error sensitivity coefficient. Moreover, at the same time, it is possible to prevent the absolute value of the manufacturing error sensitivity coefficient in other components from increasing. Therefore, the designing means of the present invention can design more efficiently than the conventional designing method. It should be noted that the manufacturing error sensitivity coefficient is caused by an error of a constituent element of an optical element alone (for example, a radius of curvature of an optical action surface, a surface interval, a refractive index, etc.), and a constituent element of optical elements (for example, an optical element). The distance between the elements, the group distance between the optical element groups, and the like) are caused by an error.

Here, an example of f _err is shown. It is assumed that it is known that a manufacturing error easily occurs in the curvature in the manufacturing process. In this case, the spherical aberration becomes worse due to the error in the radius of curvature. Therefore, in designing an optical system, it is important to suppress fluctuations in spherical aberration performance as much as possible. Assuming that the optical system is composed of an n-side optical action surface, the evaluation function f _err is the manufacturing error sensitivity coefficient C of the curvature r _i of the i-th surface of the spherical aberration coefficient I.
It is preferable to use (I, r _i ) as in the following equation.

[0033]

[Equation 7] However, k in the formula is an arbitrary real number.

By using such an evaluation function, it is possible to reduce the absolute value of the manufacturing error sensitivity coefficient on the optical action surface where the absolute value of the manufacturing error sensitivity coefficient of the spherical aberration coefficient is large. This makes it possible to reduce fluctuations in spherical aberration performance even in the manufacturing process in which a manufacturing error is likely to occur in the curvature. At the same time, it is possible to prevent the absolute value of the manufacturing error sensitivity coefficient from becoming large in the process of optimization even for an optical action surface whose absolute value of the manufacturing error sensitivity coefficient is already sufficiently small. As a result, it is possible to design more efficiently than the conventional design method.

In the above example, the case where the manufacturing error sensitivity coefficient is based on the spherical aberration coefficient is described, but the same effect can be obtained even if the coma aberration coefficient, the astigmatism coefficient, and the Petzval aberration coefficient are changed. Needless to say.

The evaluation item term (variable) of the evaluation function f _err may be the sum of powers of the absolute values of the manufacturing error sensitivity coefficients of one type of aberration coefficient. It can also be the power of the absolute value of the sum of, or the power of the sum of the absolute values. In this case, it is needless to say that the same effect as described above can be obtained, and further, it is possible to reduce the aberration change due to each manufacturing error in the optical system in a well-balanced manner, which is preferable.

Further, it is preferable that an arbitrary real number satisfy the condition of 1 <k <4. If the above conditions are not satisfied, it will be difficult to achieve both optimization of the aberration value and suppression of changes in the performance of the optical system due to manufacturing errors. It is preferable that k = 2. By doing so, the method of designing the optical system in the present invention can be operated most effectively. In addition, the speed of computer calculation can be further increased.

The procedure of the optical system designing method according to this embodiment will be described with reference to the flowchart shown in FIG.

First, in step 1, initial data of the optical system is prepared. This initial data is data of the ideal optical system. Next, in step 2, parameters related to the conventional evaluation function such as target values and weights of various aberrations and parameters related to the evaluation function introduced by the present design method are set. Then, in step 3, the damping factor is set. Here, the default value of the damping factor is usually set. The evaluation function is determined by the above steps.

Next, in step 4, a determinant for the evaluation function, that is, a simultaneous equation is created to obtain a solution. In the following step 5, the solution obtained in step 4 is evaluated. A specific example of evaluation is aberration.

That is, the aberration in the optical system before step 4 (aberration before correction) and the aberration in the optical system obtained after step 4 (aberration after correction) are compared. Here, when the value of the post-correction aberration is smaller than the value of the pre-correction aberration and the value changes greatly, it is determined that further improvement can be expected. In this case, the degree of improvement is large, and the process returns to step 3. If the value of the post-correction aberration is smaller than the value of the pre-correction aberration, but the value does not change significantly, it is determined that further improvement cannot be expected. In this case, the degree of improvement is small, and the process proceeds to step 6.

In step 6, if the obtained design value satisfies the design target, the design is finished. If not satisfied, the process returns to step 2, the design condition is changed and the design is continued.

In the above flow, steps 3 to 5 are suitable for the computer program.

Examples will be shown below. Example 1 The optical system of this example is an optical system including three lenses. In this embodiment, it is assumed that a manufacturing error occurs in the curvature in the manufacturing process. The design specification that gives the error of the radius of curvature on the optical action surface by the number of Newtons and is uniformly ± 20 on each surface is image height 21.6mm, focal length 50mm, FNO =
It is 4.0. In addition, the performance is evaluated by MTF (spatial frequency 35 line pairs / mm) at the center of the screen and radial (R) and tangential (T) direction MTF (spatial frequency) at the peripheral image height of 15.12 mm.
Evaluate with 20 line pairs / mm).

First, Table 1 shows lens data (ideal optical system) in the case of designing without considering manufacturing errors.

[0046] [Table 1] Surface number Curvature radius Spacing Refractive index Abbe number Object plane ∞ ∞    1 19.6999 6.8878 1.73400 51.47    2 218.2422 3.1040    3 -44.5881 1.5830 1.69895 30.13    4 18.9753 0.3814 Aperture surface ∞ 3.4306    6 91.6942 5.6837 1.88300 40.76    7 -38.2543 36.4824 Image plane ∞

Table 2 shows the performance of this ideal optical system and the performance when an error is given to each surface. Table 2
In, the numerical values next to the central performance and peripheral performances (R) and (T) are MTF values. (R) means radial direction, and (T) means tangential direction. Also, the numerical value below ± 20 shows the amount of change in MTF as a percentage. +20 or -20 Newton on the surface after each surface number.
This is the value when the book error is given.

[0048] [Table 2]           Core performance 55.46 Peripheral performance (R) 14.51 Peripheral performance (T) 66.49  Face number +20 -20 -20 +20 -20 +20 -20   1 -1.61 1.39 -0.29 0.71 1.25 -1.43   2 -1.60 1.30 -8.67 11.47 6.64 -17.92   3 -4.41 2.33 -5.48 9.15 3.94 -11.87   4 -3.36 2.47 -6.26 11.78 7.92 -13.91   6 -1.75 1.87 -8.65 11.57 7.13 -16.25   7 -1.77 1.54 -0.63 0.91 -0.97 0.47

Table 3 shows the maximum value, the minimum value, and the variance of the amount of change in MTF in the central performance and peripheral performances (R) and (T).

[0050]

Also, the third, fifth, and
The square sum of the manufacturing error sensitivity coefficient of the 7th-order spherical aberration coefficient and 3
Table 4 shows the sum of squares of the manufacturing error sensitivity coefficient of the fifth-order and fifth-order coma aberration coefficients.

[Table 4] Third-order spherical aberration 0.00318 5th order spherical aberration 0.00031 7th-order spherical aberration 0.000012 Third-order coma aberration 0.01054 5th-order coma aberration 0.00031

Next, with the lens data of Table 1 as initial data, the evaluation function f _err was set to design the optical system. The evaluation items of the evaluation function f _err are the sum of squares of manufacturing error sensitivity of third-order, fifth-order, and seventh-order spherical aberration coefficients and the square sum of manufacturing error sensitivity of third-order and fifth-order coma aberration coefficients. . The lens data obtained as a result are shown in Table 5.

[0054] [Table 5] Surface number Curvature radius Spacing Refractive index Abbe number Object plane ∞ ∞    1 21.7918 7.5000 1.73400 51.47    2 203.4786 3.9221    3 -40.9492 1.7126 1.69895 30.13    4 21.1934 0.5959 Aperture surface ∞ 3.3196    6 86.1305 5.9747 1.88300 40.76    7 35.9098 36.5710 Image plane ∞

The performance when an error is given to each surface is as follows.
It becomes like Table 6.

[0056] [Table 6]           Core performance 41.7715 Peripheral performance (R) 19.23 Peripheral performance (T) 58.44  Face number +20 -20 -20 +20 -20 +20 -20   1 -1.06 1.01 0.19 -0.21 -0.09 0.19   2 -1.20 1.21 -6.03 7.28 8.49 -15.79   3 -3.86 3.01 -4.02 6.19 6.57 -12.06   4 -3.06 2.88 -3.97 7.07 5.28 -9.98   5 0.00 0.00 0.00 0.00-0.00 -0.00   6 -1.48 1.63 -6.25 8.23 8.23 -16.17   7 -1.71 1.66 -0.18 0.04-0.17 -0.01

Table 7 shows the maximum value, the minimum value, and the variance of the amount of change in the MTF in the central performance and the peripheral performances (R) and (T).

[0058]

Comparing Table 2 and Table 6, the MTF values in the central performance and the peripheral performance (T) are slightly smaller than those in the ideal optical system. On the other hand, MTF in peripheral performance (R)
The value of is slightly larger. Then, comparing Table 3 and Table 7, the variation in the change in MTF value, that is, the variance is about 4% from 2.27 to 2.18 at the center and 7.58 at the periphery (R).
To 5.09, about 33%; around (T) from 9.11 to 8.72, about 4
It is as small as%. That is, even if there is an error in the radius of curvature of the optical action surface, it is possible to obtain an optical system that is less affected by the error.

The third, fifth, and
The square sum of the manufacturing error sensitivity coefficient of the 7th-order spherical aberration coefficient and 3
Table 8 shows the sum of squares of the manufacturing error sensitivity coefficient of the fifth-order and fifth-order coma aberration coefficients. The value is smaller than that in Table 4. As described above, the fact that the error sensitivity is small shows that the optical system in Table 5 is an optical system that is less affected by manufacturing errors.

[Table 8] Third-order spherical aberration 0.00147 5th-order spherical aberration 0.00012 7th-order spherical aberration 0.000004 Third-order coma aberration 0.00559 5th-order coma aberration 0.00018

<Embodiment 2> In this embodiment, it is assumed that a manufacturing error occurs in the surface spacing in the manufacturing process. The ideal optical system of the present embodiment is the optical system shown in Table 1 of the first embodiment.
In this embodiment, it is assumed that the surface spacing changes by ± 0.2 mm due to manufacturing error. Therefore, the performance when an error is given to each interval is as shown in Table 9.

[0063] [Table 9]           Core performance 55.46 Peripheral performance (R) 14.51 Peripheral performance (T) 64.99  Surface number + 0.2mm -0.2mm + 0.2mm -0.2mm + 0.2mm -0.2mm   1 -3.22 2.51 7.29 -7.14 -8.96 5.71   2 -6.61 4.48 4.00 -2.99 -2.48 -2.31   3 -0.36 0.37 18.98 -14.45 -36.72 1.01   4 -0.55 0.54 14.07 -11.93 -21.15 3.80   6 0.12 -0.12 6.53 -6.04 -10.84 5.45   7 -0.21 0.21 -0.15 0.32 0.38 -0.48

Table 10 shows the maximum value, the minimum value, and the variance of the amount of change in the MTF in the central performance and the peripheral performances (R) and (T).

[0065]

The third, fifth, and
The square sum of the manufacturing error sensitivity coefficient of the 7th-order spherical aberration coefficient and 3
Table 11 shows the sum of squares of the manufacturing error sensitivity coefficient of the fifth-order and fifth-order coma aberration coefficients.

[Table 11] Third-order spherical aberration 0.00233 5th-order spherical aberration 0.00016 7th-order spherical aberration 0.000006 Third-order coma aberration 0.00808 5th-order spherical aberration 0.00032

Next, with the lens data of Table 1 as initial data, the evaluation function f _err was set to design the optical system. The evaluation items of the evaluation function f _err are the sum of squares of manufacturing error sensitivity of third-order, fifth-order, and seventh-order spherical aberration coefficients and the square sum of manufacturing error sensitivity of third-order and fifth-order coma aberration coefficients. . Table 12 shows the lens data obtained as a result.

[0069] [Table 12] Surface number Curvature radius Spacing Refractive index Abbe number Object plane ∞ ∞    1 20.6056 7.1750 1.73400 51.47    2 171.2749 3.4372    3 -45.4040 1.6212 1.69895 30.13    4 19.8138 0.0939 Aperture surface ∞ 4.0494    6 78.6995 5.8624 1.88300 40.76    7 -38.9327 36.6634 Image plane ∞

The performance when an error is given to each surface is
It becomes like Table 13.

[0071] [Table 13]           Core performance 46.64 Peripheral performance (R) 15.63 Peripheral performance (T) 63.24  Surface number + 0.2mm -0.2mm + 0.2mm -0.2mm + 0.2mm -0.2mm   1 -2.78 2.57 6.25 -5.98 -7.09 3.82   2 -5.24 4.60 5.46 -5.41 -1.92 -1.55   3 -0.29 0.24 14.89 -10.77 -31.99 1.45   4 -0.66 0.66 10.48 -8.61 -17.49 6.73   6 0.12 -0.13 4.92 -4.49 -10.56 6.03   7 -0.20 0.21 -0.15 0.30 0.20 -0.19

Table 14 shows the maximum value, the minimum value, and the variance of the amount of change in the MTF in the central performance and the peripheral performances (R) and (T).

[Table 14] Maximum 4.60 14.89 6.73 Min -5.24 -10.77 -31.99 Variance 2.31 7.62 10.67

Comparing Table 9 and Table 13, the MTF values in the central performance and the peripheral performance (T) are slightly smaller than those in the ideal optical system. On the other hand, MT in peripheral performance (R)
The value of F is slightly larger. Then, comparing Table 10 and Table 14, the variation in the change in the MTF value, that is, the variance is about 11% from 2.59 to 2.31 at the center, and the peripheral (R)
21% from 9.62 to 7.62, 11.95 to 1 in the surrounding area (T)
It has decreased to 0.67, which is about 11%. That is, even if there is an error in the surface spacing of the optical action surfaces, it is possible to obtain an optical system that is less affected by the error.

The third order, the fifth order, and the seventh order due to the variation of the surface spacing.
Next, the sum of squares of the manufacturing error sensitivity coefficient of the spherical aberration coefficient and 3
Table 15 shows the sum of squares of the manufacturing error sensitivity coefficient of the next-order and fifth-order coma aberration coefficients. The value is smaller than that in Table 11. As described above, the fact that the error sensitivity is small also indicates that the optical system in Table 12 is an optical system that is less affected by the manufacturing error.

[Table 15] Third-order spherical aberration 0.00145 5th-order spherical aberration 0.00008 7th-order spherical aberration 0.000003 Third-order coma aberration 0.00650 5th-order coma 0.00014

The present invention has been described above, but the present invention includes the following.

[1] In the method of designing an optical system using an evaluation function, the evaluation function has at least one evaluation item associated with a manufacturing error, and the evaluation item includes a manufacturing error sensitivity coefficient, A program for designing an optical system, wherein the sensitivity coefficient is represented by a minute change in optical performance that occurs when a component of the optical system is slightly changed. [2] An optical system design program characterized by recording the design program of [1] above. [3] An optical system designed using the design method according to any one of claims 1 to 3 or the design program for the optical system according to [2].

[4] An optical device which is designed by using the design method according to any one of claims 1 to 3 or the design program for the optical system according to the above [2].

[0080]

As described above, according to the present invention, it is possible to efficiently design an optical system which is suitable for execution by a computer and which suppresses a change in performance of the optical system due to a manufacturing error in addition to an optical design such as various aberrations. It is possible to provide a designing method of an optical system for

[Brief description of drawings]

FIG. 1 is a flowchart showing a procedure of a design method of the present invention.

Claims (3)

[Claims] 1. A method of designing an optical system using an evaluation function, wherein the evaluation function has at least one evaluation item associated with a manufacturing error, the evaluation item including a manufacturing error sensitivity coefficient, and the manufacturing error sensitivity. The coefficient is represented by a minute change in optical performance that occurs when a component of the optical system is minutely changed. 2. A step of calculating paraxial ray quantities in a predetermined state of the optical system, a step of calculating an aberration coefficient in the state, and a step of calculating a manufacturing error sensitivity coefficient from the state. The optical system designing method according to claim 1, further comprising: 3. A method for calculating a power sum of manufacturing error sensitivity coefficients from a plurality of manufacturing errors, wherein the evaluation item includes a power sum of manufacturing error sensitivity coefficients.
Design method of the optical system described.