Method for designing microscope lenses that extend depth of field and method for manufacturing the same.

Abstract

This invention provides a method for designing a microscope lens capable of extending the depth of focus in the optical axis direction, and a method for manufacturing the same. [Solution] The microscope lens design method is a method for designing a depth of field extension lens 4 inserted between an objective lens 2 and an imaging lens 3, wherein the depth of field extension lens 4 is made by a predetermined coefficient C n Using this, the section function H(x,y) is used to model the light around the focusing position f0, and the wave function of the light irradiated from the object under test, passing through the objective lens 2 and the depth of field extension lens 4 to the image plane C of the imaging lens 3 is calculated. Based on the wave function, a point image distribution function I(x,y,z) representing the brightness value at the image plane C of the imaging lens 3 is calculated, and an evaluation function E(C) is used to represent the ratio of the brightness value at the periphery to the brightness value around the optical axis. n A predetermined coefficient C is formulated so that the ratio of luminance values ​​is minimized in a predetermined range around the focus position f0. n By calculating this, the cross-sectional function of the depth-of-focus extension lens 4 is determined.

Description

[Technical Field]

[0001] This invention relates to a method for designing and manufacturing a microscope lens that extends the depth of field. [Background technology]

[0002] Generally, in optical microscopes having an objective lens and an imaging lens, it is preferable to increase the numerical aperture of the objective lens to improve resolution. However, in this case, the depth of focus in the optical axis direction is inversely proportional to the numerical aperture and is therefore known to become shorter.

[0003] On the other hand, when observing three-dimensional tissues with thickness in the optical axis direction using flow cytometry and / or light sheet microscopy, it is necessary to extend the depth of focus of the microscope while maintaining resolution.

[0004] In contrast, Non-Patent Document 1 discloses a microscope having a stepped lens in which multiple discs of different diameters are stacked in the optical axis direction, as a depth-of-focus extension lens placed between the objective lens and the imaging lens of the microscope.

[0005] Non-patent document 2 discloses a microscope having a conical axicon lens as the depth-of-focus extension lens that can obtain a depth of focus of several tens of micrometers. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] A new approach to extended focus for high-speed high-resolution biological microscopy. In Three-Dimensional and Multidimensional Microscopy: Image Acquisition and Processing XIII; SPIE: Washington, DC, USA, 2006. [Non-Patent Document 2] Two-photon scanned light sheet fluorescence microscopy with axicon imaging for fast volumetric imaging, Journal of Biomedical Optics, Vol. 26, Issue 11, 116503(November 2021) [Overview of the project] [Problems that the invention aims to solve]

[0007] There is a need for even greater depth of field extension in this type of lens.

[0008] The object of this invention is to provide a method for designing a microscope lens capable of extending the depth of focus in the optical axis direction, and a method for manufacturing the same. [Means for solving the problem]

[0009] One aspect of the present invention is, A method for designing a depth-of-focus extension lens to be inserted between an objective lens and an imaging lens, The depth-of-focus extension lens is modeled using a cross-sectional function that represents the surface position in the optical axis direction, with the position of the cross-sectional shape in a direction perpendicular to the optical axis direction being a variable, using a predetermined coefficient. The wave function of light emitted from the object to be measured, passing through the objective lens and the depth-of-focus extension lens to the image plane of the imaging lens, is calculated using the position in the optical axis direction and the position in a direction perpendicular to the optical axis direction as variables, around the focal position. Based on the wave function, calculate a point image distribution function that represents the brightness value at the image plane of the imaging lens. By calculating the luminance values ​​of the central and peripheral parts around the optical axis using the point image distribution function, and formulating an evaluation function that represents the ratio of the luminance value of the peripheral part to the luminance value of the central part, The cross-sectional function of the depth-of-focus extension lens is determined by numerically calculating a predetermined coefficient such that the ratio of the luminance values ​​calculated by the evaluation function is minimized in a predetermined range around the focusing position. This invention provides a method for designing microscope lenses that extend the depth of field, including the following:

[0010] Other aspects of the present invention include: A method for manufacturing a depth-of-focus extension lens inserted between an objective lens and an imaging lens, The depth-of-focus extension lens is modeled using a cross-sectional function that represents the surface position in the optical axis direction, with the position of the cross-sectional shape in a direction perpendicular to the optical axis direction being a variable, using a predetermined coefficient. Around the focal position, the wave function of light irradiated from the object to be measured and reaching the image plane of the imaging lens via the objective lens and the depth of field extension lens is calculated, with the position in the optical axis direction and the position in a direction perpendicular to the optical axis direction around the focal position as variables. Based on the wave function, a point image distribution function representing the brightness value at the image plane of the imaging lens is calculated. The luminance values ​​of the central and peripheral parts around the optical axis are calculated using the point image distribution function, and an evaluation function is formulated that represents the ratio of the luminance value of the peripheral part to the luminance value of the central part. Calculating the predetermined coefficient by numerical calculation so that the ratio of the luminance values calculated by the evaluation function is minimized in a predetermined range around the in-focus position, thereby determining the cross-sectional function of the depth of focus extension lens, manufacturing a depth of focus extension lens based on the cross-sectional function, Provided is a method for manufacturing a microscope lens that extends the depth of focus.

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a design method and a manufacturing method for a microscope lens capable of extending the depth of focus in the optical axis direction.

Brief Description of the Drawings

[0012] [Figure 1] Schematic diagram of a microscope including a depth of focus extension lens designed by the design method of the microscope lens according to the present invention. [Figure 2] Flowchart of the design method of the microscope lens according to the present invention. [Figure 3] Flowchart for obtaining each wave function on the object plane, pupil plane, and image plane. [Figure 4] Cross-sectional function of the depth of focus extension lens. [Figure 5] Point image distribution on the image plane when using the designed depth of focus extension lens. [Figure 6] Point image distribution on the image plane when using an axicon lens as a comparative example. [Figure 7A] Point image distribution on the image plane when using the designed depth of focus extension lens and changing to another objective lens. [Figure 7B] Point image distribution on the image plane when using the designed depth of focus extension lens and further changing to another objective lens. [Figure 8] Point image distribution on the image plane when using the designed depth of focus extension lens and changing the fluorescence wavelength of the sample.

Embodiments for Carrying Out the Invention

[0013] Embodiments of the present invention will be described below with reference to the drawings. The following description is essentially illustrative and is not intended to limit the present invention, its applications, or its uses.

[0014] Figure 1 shows a microscope system 1 according to one embodiment of the present invention. As shown in Figure 1, the microscope system 1 has an objective lens 2, an imaging lens 3 positioned opposite the objective lens 2, and a depth-of-focus extension lens 4 positioned between the objective lens 2 and the imaging lens 3. The objective lens 2, the imaging lens 3, and the depth-of-focus extension lens 4 are positioned with their optical axes aligned. An optical axis is a hypothetical straight line that passes through the center of the lens and intersects the lens surface perpendicularly.

[0015] In the following explanation, the optical axis direction is defined as the Z direction, the vertical direction in Figure 1 of each lens perpendicular to the Z direction is defined as the X direction, and the direction perpendicular to the Z direction and the X direction is defined as the Y direction. In the following formulas, the x, y, and z coordinates are defined as the position of the optical axis being 0 in the x and y coordinates, and the focal position f0 being 0 in the z coordinate. Furthermore, the direction toward objective lens 2 from the focal position f0 is defined as the positive z direction, and the direction away from objective lens 2 is defined as the negative z direction. The focal position f0 is the position where the image is in focus. The focal position f0 is the position of a point object relative to the lens when a point object is imaged as a point on the image plane through the lens.

[0016] A sample (object to be measured) S is positioned on the opposite side of the objective lens 2 of the microscope system 1 from the imaging lens 3. The sample S is positioned at the focusing position f0 of the objective lens 2. Because the sample S is positioned at the focusing position f0, for example, light emitted by the fluorescent sample S (on the object surface A) does not form an image in the objective lens 2, but enters the imaging lens 3 as parallel light at infinity, and is focused on the side of the imaging lens 3 opposite the objective lens 2 to form the image plane C.

[0017] In this embodiment, the microscope system 1 employs a so-called 4F optical system. Therefore, the objective lens 2 and the imaging lens 3 are arranged such that, if the focal length of the objective lens 2 is f1 and the focal length of the imaging lens 3 is f2, the distance between the object plane A and the image plane C is 2f1 + 2f2.

[0018] The depth of focus extension lens 4 is positioned on the pupil plane B of the microscope system 1. The pupil plane B is the position where the focal point on the imaging lens 3 side of the objective lens 2 coincides with the focal point on the objective lens 2 side of the imaging lens 3. The depth of focus extension lens 4 positioned on the pupil plane B modulates the phase of the light incident on lens 4. Because the depth of focus extension lens 4 extends the depth of focus (DOF) of the objective lens 2, it becomes possible to observe a sample S that has thickness in the optical axis direction.

[0019] Depth of focus (DOF) is the range in which light remains within the acceptable circle of confusion diameter at positions shifted along the optical axis, with the focal position f0 of objective lens 2 being defined as 0. In the context of microscopic observation, DOF refers to the range in which an image remains clearly visible even when the focal plane is shifted before or after the focal position f0.

[0020] In the microscope system 1 equipped with a 4F optical system as described herein, for example, a sample S is fluoresced by a laser or the like, and the light emitted by the fluoresced sample S is incident on the objective lens 2. Since the sample S is positioned at the focus position f0 of the objective lens 2, the light incident on the objective lens 2 is emitted as parallel light toward the rear of the objective lens 2.

[0021] When parallel light emitted from objective lens 2 enters depth-of-focus extension lens 4, the amplitude and / or phase of the light are modulated by depth-of-focus extension lens 4, thereby controlling the convergence and divergence of the light. As a result, the depth of focus is extended both before and after the focusing position f0.

[0022] Light that passes through the depth-of-focus extension lens 4 enters the imaging lens 3 and is focused at the image plane C behind the imaging lens 3.

[0023] This document explains the design method for lenses with extended depth of field.

[0024] As shown in Figure 2, in the design method for the depth of field extension lens 4, first in step S1, the depth of field extension lens 4 is made by a predetermined coefficient C n Using this, the surface position in the optical axis direction is represented by the section function H(x,y), where the position in the direction perpendicular to the optical axis direction of the cross-sectional shape is a variable.

[0025] In step S2, the wave function of light emitted from the object to be measured S, passing through the objective lens 2 and the depth of field extension lens 4 to the image plane C of the imaging lens 3, is calculated around the focusing position f0, using the position in the optical axis direction and the position in a direction perpendicular to the optical axis direction as variables.

[0026] In step S3, a point image distribution function I(x,y,z) representing the brightness value at the image plane C of the imaging lens 3 is calculated based on the wave function.

[0027] In step S4, the luminance values ​​of the central and peripheral parts around the optical axis are calculated using the point image distribution function I(x,y,z), and an evaluation function E(C) is used to represent the ratio of the luminance value of the peripheral part to the luminance value of the central part. n ) will be formulated.

[0028] In step S5, the evaluation function E(C) n A predetermined coefficient C is determined by numerical calculation so that the ratio of luminance values ​​calculated by ) is minimized in a predetermined range around the focus position f0. n By calculating this, the cross-sectional function H(x,y) of the depth-of-focus extension lens 4 is determined.

[0029] In step S1, the modeling of the depth-of-focus extension lens 4 involves a predetermined coefficient C. nUsing this, the section function H(x,y) is determined, which represents the surface position in the optical axis direction (Z direction), with the position of the cross-sectional shape in a direction perpendicular to the optical axis direction as a variable. The section function H(x,y) is rotationally symmetric with respect to the optical axis and is set by a polynomial. In this embodiment, the polynomial is a 4th-degree polynomial, as shown in Equation 1. The section function H(x,y) determines the position in the optical axis direction (Z direction position, lens thickness) of the depth of focus extension lens 4 at a position perpendicular to the optical axis direction.

[0030]

number

[0031] Next, we will explain the calculation of the wave function of the light emitted from the object S in step S2. Figure 3 is a flowchart illustrating the calculation of the wave function of the light emitted from the object in step S2, which passes through each lens and reaches the image plane.

[0032] As shown in Figure 3, the following steps are performed: step S11 to calculate the first wave function Q1 generated from the sample S; step S12 to calculate the second wave function Q2 at the pupil plane B after passing through the objective lens 2, which is calculated based on the first wave function Q1; step S13 to calculate the third wave function Q3 at the pupil plane B after the phase shift due to the depth of focus extension lens 4 has been multiplied based on the second wave function Q2; and step S14 to calculate the fourth wave function Q4 at the image plane C after passing through the imaging lens 3, based on the third wave function Q3.

[0033] The first wave function Q1 in step S11 can be expressed using Scalar Debye theory as shown in the following equation 2, representing the fluorescence of the excited sample S. The first wave function Q1 indicates the phase and amplitude of the light wave emitted from the sample S around the focal position f0. Note that the first wave function Q1 describes the point image distribution function due to a high numerical aperture (NA) lens. The point image distribution function is a function that describes how a point source spreads due to diffraction.

[0034]

number

[0035] Here, scalar Debye theory is obtained by approximating the solution to the scalar wave equation, derived from Maxwell's equations (electric field E, magnetic field H, magnetic flux density B, and electric flux density D), with a function that can be expressed using the Rayleigh-Sommerfeld diffraction integral equation.

[0036] In this embodiment, scalar Debye theory was used to calculate the first wavefunction Q1, but the invention is not limited to this; for example, Fresnel's diffraction formula and / or vector Debye theory may be used.

[0037] The second wave function Q2 in step S12 is the wave function at pupil plane B, and is calculated by performing a Fourier transform on the first wave function Q1. If x' and y' are the coordinates at pupil plane B, λ is the wavelength fluoresced by sample S, and F is the focal length of objective lens 2, then it is expressed as shown in Equation 3. The second wave function Q2 represents the phase and amplitude of the light wave transmitted through objective lens 2 from sample S around the focal position f0 at pupil plane B.

[0038]

number

[0039] Generally, the wave function from one focal point to the other of a lens can be obtained by performing a Fourier transform on the wave function at one focal point of the lens. In this embodiment, the focal point on the sample S side of the objective lens 2 coincides with the sample position (object plane) A, and the focal point on the image plane C side of the objective lens 2 coincides with the pupil plane B. Therefore, by performing a Fourier transform on the first wave function Q1, the wave function at the pupil plane B (second wave function) Q2 is obtained.

[0040] In this embodiment, the Fourier transform was used to calculate the second wave function Q2, but it is not limited to this; for example, Fresnel's diffraction formula may be used.

[0041] The third wave function Q3 in step S13 can be calculated by multiplying the second wave function Q2 by the phase shift P due to the depth-of-focus extension lens 4, and can be expressed by equation 4. The third wave function Q3 represents the phase and amplitude of the light wave emitted from the sample S around the focal position f0 at the pupil plane B position, transmitted through the objective lens 2 and the depth-of-focus extension lens 4.

[0042]

number

[0043] The phase shift P is, This is represented in TIFF2026049543000008.tif645. The phase shift P depends on the shape and / or material of the depth-of-focus extension lens 4, etc. The parameters of the phase shift P include, for example, the thickness and / or curvature of the depth-of-focus extension lens 4 at each point, and these parameters modulate the phase, amplitude, and optical path of the light.

[0044] The fourth wave function Q4 in step S14 can be calculated by performing a Fourier transform on the third wave function Q3, for the same reasons as the relationship between the first wave function Q1 and the second wave function Q2, and can be expressed by equation 5. The fourth wave function Q4 represents the phase and amplitude of the light wave emitted from the sample S around the focal position f0 at position C on the image plane, and transmitted through the objective lens 2, the depth of field extension lens 4, and the imaging lens 3.

[0045]

number

[0046] In this embodiment, the Fourier transform was used to calculate the fourth wave function Q4, but the method is not limited to this; for example, Fresnel's diffraction formula may be used. With this, the calculation of the wave function in step S2 is completed.

[0047] Next, step S3 in the design method for the depth-of-focus extension lens 4 will be explained. In step S3, the point image distribution function I(x,y,z) representing the brightness value at the image plane C of the imaging lens 3 is calculated by squaring the absolute value of the fourth wave function Q4 calculated in step S2, and the point image distribution function I(x,y,z) at the image plane C can be calculated and expressed by equation 6. In step S3, the point image distribution function I(x,y,z) around the focusing position f0, which includes the desired depth of focus range, is calculated.

[0048]

number

[0049] Next, we will explain step S4 in the design method for the depth-of-focus extension lens 4. In step S4, the luminance values ​​of the central and peripheral parts around the optical axis are calculated using the point image distribution function I(x,y,z) calculated in step S3, and an evaluation function E(C) is used to represent the ratio of the luminance value of the peripheral part to the luminance value of the central part. n ) will be formulated. Evaluation function E(C n ) can be represented by the number 7.

[0050] [Number]

[0051] In this embodiment, it is preferable that the central part of the point image distribution function I(x, y, z) generally coincides with the resolution defined by the numerical aperture of the objective lens 2. For example, when the specifications of the objective lens 2 are a magnification of 16 times and a numerical aperture NA of 0.8, a resolution of 400 nm can be obtained. In this case, the central part of the point image distribution function may be set to 300 nm or less. The peripheral part of the point image distribution function may be any region outside the central part in the radial direction. For example, when the above objective lens 2 is applied, it is a region larger than 300 nm.

[0052] Finally, step S5 in the design method of the depth of focus extension lens 4 will be described. In step S5, the ratio of the luminance values calculated by the evaluation function E(C n ) is minimized in a predetermined range around the in-focus position f0 by numerical calculation to calculate a predetermined coefficient C n , thereby determining the cross-sectional function H(x, y) of the depth of focus extension lens 4.

[0053] The predetermined range around the in-focus position f0 is preferably a range including the required depth of focus. More specifically, the predetermined range around the in-focus position f0 may be a range of 50 times the depth of focus when the objective lens 2 with the same numerical aperture is applied without using the depth of focus extension lens 4. In this embodiment, when the objective lens 2 with a numerical aperture NA of 0.8 is applied, the depth of focus without using the depth of focus extension lens 4 is 2 μm. Therefore, the predetermined range around the in-focus position f0 is set to a range where the Z-direction position is -100 μm or more and 100 μm or less with the in-focus position f0 being 0.

[0054] Also, minimizing the ratio of the luminance values means that in the calculation of ADAM, it is judged by a typical convergence judgment method in the optimization method. For example, when the change in the evaluation function becomes 10 -n or less, or when the change in the parameter Cn becomes 10 -nThis setting is applied when the following conditions are met. Note that n is arbitrary, but for example, it may be set to 6 or more and 10 or less.

[0055] In Step S5, the coefficient C of the polynomial (section function) from Math 1. n To optimize this, the optimization method calculation process is performed. In this embodiment, the global optimization method ADAM (Adaptive moment estimation) is applied to the optimization method calculation process. For more details, see C n By changing the phase-shifted term of the third wavefunction Q3, the fourth wavefunction Q4 and the point image distribution function I(x,y,z) at the image plane C change. n The optimization method is then performed so that the brightness value at the periphery of the point distribution function I(x,y,z) is minimized relative to the brightness value at the center.

[0056] In the specific calculation of ADAM, a subset of parameters (mini-batch) is used in each iteration to perform stochastic gradient descent using Equation 8, progressing in small steps along the negative gradient of the parameters to minimize the value of the evaluation function. In this embodiment, ADAM is applied as the computational process for the optimization method, but it is not limited to this, and for example, steepest descent, stochastic gradient descent (SDG), and mini-batch learning SGD may also be applied.

[0057]

number

[0058] The termination conditions for the calculation process can be set as appropriate, and may be determined, for example, by comparison with a predetermined threshold or by the number of calculations.

[0059] Figure 4 shows the coefficient C obtained from the above steps. nAnd a depth-of-focus extension lens 4 designed by a polynomial is shown. In this embodiment, the cross-sectional shape of the objective lens 2 side of the depth-of-focus extension lens 4 is concave, with the thickness decreasing towards the radially inward direction. The cross-sectional shape of the depth-of-focus extension lens 4 shows that the amount of increase in lens thickness increases from the radially inward direction. Although the cross-sectional shape of the depth-of-focus extension lens 4 has been described as concave, it may also be convex, with the thickness increasing towards the radially inward direction. In this case, the cross-sectional function shown in Figure 4 can be used to ensure that the amount of decrease in lens thickness increases from the radially inward direction to the radially outward direction.

[0060] [Examples] Figure 5 shows the numerical calculation results of the point image distribution on the image plane of a microscope using the depth-of-focus extension lens 4 formed using the design and manufacturing methods described above.

[0061] Figure 5(a) shows an image with maximum intensity projection in the Y direction. 0 μm coincides with the center of the thickness direction of objective lens 2. Within the region between -100 μm and 0 μm, located on the sample S side of objective lens 2, the depth of focus extension region extends in front of and behind the optical axis, centered around the focus position f0, where the light intensity (luminance) is highest, at approximately the midpoint (50 μm).

[0062] Figure 5(b) shows the change in light intensity (vertical axis) when the Z position (horizontal axis) along the optical axis is changed. As shown in Figure 5(b), a depth of focus of 46.6 μm was obtained with the depth of focus extension lens 4. Here, the depth of focus was measured using the full width at half maximum of the luminance value.

[0063] Figure 5(c) shows the change in light intensity (vertical axis) when the radial X position (horizontal axis) is changed. The center 0 of the X position coincides with the position of the optical axis. As shown in Figure 5(c), a central side lobe ratio of 0.166 was obtained with the depth of field extension lens 4. The central side lobe ratio is the ratio of the light intensity of the side lobes extending in front of and behind the optical axis position to the light intensity of the main lobe that occurs at the optical axis position. Here, the main lobe is the peak at the center of the optical axis, as shown in Figure 5(c), and the side lobes are the peaks around the main lobe.

[0064] As shown in Figures 5(a) to (c), the depth-of-focus extension lens 4 designed using the above design method resulted in an extended depth of field while suppressing side lobes.

[0065] Figure 6 shows experimental results when a conical lens (axicon lens) is used instead of the depth-of-focus extension lens 4, as a comparative example. Figure 6(a) shows an image with maximum intensity projection in the Y direction. 0 μm coincides with the center in the thickness direction of objective lens 2. Within the region between -100 μm and 0 μm, located on the sample S side of objective lens 2, the depth-of-focus extension region extends in the negative direction from the focal position with the highest light intensity, which is approximately at the midpoint (50 μm).

[0066] Figure 6(b) shows the change in light intensity (vertical axis) when the Z position (horizontal axis) along the optical axis is changed. As shown in Figure 6(b), a depth of focus of 39.1 μm was obtained with the conical lens. Here, the depth of focus was measured using the full width at half maximum of the luminance value.

[0067] Figure 6(c) shows the change in light intensity (vertical axis) when the radial X position (horizontal axis) is changed. The center of the X position 0 coincides with the position of the optical axis. As shown in Figure 6(c), a central sidelobe ratio of 0.237 was obtained with the conical lens. It was confirmed that the central sidelobe ratio worsened with the conical lens compared to the depth of field extension lens 4.

[0068] Figures 7A and 7B show the verification results of the point image distribution function (PSF) when the specifications of the objective lens 2 are changed in a microscope to which the depth of field extension lens 4 is applied. The specifications of the objective lenses verified are (a) magnification 16, numerical aperture 0.8, n=1.33, (b) magnification 16, numerical aperture 0.6, n=1.33, (c) magnification 20, numerical aperture 0.6, n=1.33, and (d) magnification 16, numerical aperture 0.8, n=1.5. As shown in Figures 7A and 7B, in all cases using the objective lens, the depth of field is extended while suppressing side lobes.

[0069] Figure 8 shows the verification results of the point image distribution function (PSF) when the wavelength of fluorescence of the excited sample is changed in a microscope to which the depth of focus extension lens 4 is applied. The wavelengths verified were (a) 475 nm, (b) 520 nm, and (c) 600 nm. As shown in Figure 8, in all cases, the depth of focus is extended while suppressing side lobes.

[0070] The design and manufacturing methods for microscope lenses according to this embodiment provide the following effects.

[0071] The design method for microscope lenses is: A method for designing a depth-of-focus extension lens 4 to be inserted between an objective lens 2 and an imaging lens 3, The depth of field extension lens 4 is subjected to a predetermined coefficient C n Using this, the surface position in the optical axis direction is represented by the section function H(x,y), where the position in the direction perpendicular to the optical axis direction of the cross-sectional shape is a variable. The wave function of light emitted from the object under measurement and transmitted through the objective lens 2 and depth-of-focus extension lens 4 to the image plane C of the imaging lens 3 is calculated, using the position in the optical axis direction and the position in a direction perpendicular to the optical axis direction as variables, around the focusing position f0. Based on the wave function, calculate the point image distribution function I(x,y,z) that represents the brightness value at the image plane C of the imaging lens 3. The luminance values ​​of the central and peripheral parts around the optical axis are calculated using the point image distribution function I(x,y,z), and the evaluation function E(C) represents the ratio of the luminance value of the peripheral part to the luminance value of the central part. n ) to formulate, Evaluation function E(C n A predetermined coefficient C is determined by numerical calculation so that the ratio of luminance values ​​calculated by ) is minimized in a predetermined range around the focus position f0. n By calculating this, the cross-sectional function H(x,y) of the depth-of-focus extension lens 4 is determined. Includes.

[0072] According to the present invention, by appropriately setting the cross-sectional shape of the depth-of-focus extension lens 4, the ratio of the luminance value at the periphery to the luminance value at the center of the point image distribution function on the image plane C can be minimized in a predetermined range around the focusing position f0, thereby enabling the design of a microscope lens with a desired depth of focus.

[0073] The cross-sectional shape of the depth-of-focus extension lens 4 may be rotationally symmetric with respect to the optical axis and may also be defined by a polynomial.

[0074] With this configuration, coefficient C n By optimizing this, it is possible to design microscope lenses with the desired depth of field.

[0075] The polynomial may be a 4th-degree polynomial.

[0076] This configuration allows for the design of microscope lenses with the desired depth of field while suppressing excessive computation time.

[0077] A predetermined coefficient C nTo optimize this, you may perform calculations using an optimization method.

[0078] This configuration uses the computational processing of the optimization method to obtain a predetermined coefficient C n It is possible to find this.

[0079] The computational process for the optimization method may be the global optimization method ADAM.

[0080] This configuration allows for the design of microscope lenses with a desired depth of field using the global optimization method ADAM.

[0081] In calculating the wave function of light, Calculation of the first wave function Q1 generated from the object S under test, which is positioned on the opposite side of the imaging lens 3 of the objective lens 2, Based on the first wavefunction Q1, the second wavefunction Q2 after passing through the objective lens is calculated, Based on the second wavefunction Q2, the third wavefunction Q3 after passing through the depth-of-focus extension lens 4 is calculated, The method may also include calculating the fourth wave function Q4 at the image plane C after transmission through the imaging lens 3, based on the third wave function Q3.

[0082] With this configuration, the wave function of light irradiated from the object under measurement and transmitted through the objective lens 2 and depth-of-focus extension lens 4 to the image plane C of the imaging lens 3 can be calculated using the first to fourth wave functions Q1, Q2, Q3, and Q4, around the focal position f0.

[0083] The method for manufacturing microscope lenses is: A method for manufacturing a depth-of-focus extension lens 4, which is inserted between an objective lens 2 and an imaging lens 3, The depth of field extension lens 4 is subjected to a predetermined coefficient C n Using this, the surface position in the optical axis direction is represented by a cross-sectional function, where the position in the direction perpendicular to the optical axis direction of the cross-sectional shape is a variable. Around the focusing position f0, the wave function of light emitted from the object under test S, passing through the objective lens 2 and the depth of field extension lens 4 to the image plane C of the imaging lens 3, is calculated using the position in the optical axis direction and the position in a direction perpendicular to the optical axis direction around the focusing position f0 as variables. Based on the wave function, the point image distribution function I(x,y,z) representing the brightness value at the image plane C of the imaging lens 3 is calculated. The luminance values ​​of the central and peripheral parts around the optical axis are calculated using the point image distribution function I(x,y,z), and an evaluation function E(C) is used to represent the ratio of the luminance value of the peripheral part to the luminance value of the central part. n ) formulated, Evaluation function E(C n A predetermined coefficient C is determined by numerical calculation so that the ratio of luminance values ​​calculated by ) is minimized in a predetermined range around the focus position f0. n By calculating this, the cross-sectional function H(x,y) of the depth-of-focus extension lens 4 is determined. A depth-of-focus extension lens 4 is created based on the aforementioned cross-sectional function H(x,y).

[0084] This configuration provides a method for manufacturing a microscope lens as described in claim 1.

[0085] In this embodiment, the method for designing microscope lenses has been described in the case of application to an optical microscope, but the method for designing microscope lenses can be applied to microscope lenses for flow cytometry and / or light sheet microscopes, etc.

[0086] Furthermore, the design and manufacturing methods for microscope lenses of the present invention are not limited to the configuration of the embodiments described above, and various modifications are possible.

[0087] [Note] This disclosure includes the following aspects.

[0088] [Aspect 1] A method for designing a depth-of-focus extension lens to be inserted between an objective lens and an imaging lens, The depth-of-focus extension lens is modeled using a cross-sectional function that represents the surface position in the optical axis direction, with the position of the cross-sectional shape in a direction perpendicular to the optical axis direction being a variable, using a predetermined coefficient. The wave function of light emitted from the object to be measured, passing through the objective lens and the depth-of-focus extension lens to the image plane of the imaging lens, is calculated using the position in the optical axis direction and the position in a direction perpendicular to the optical axis direction as variables, around the focal position. Based on the wave function, calculate a point image distribution function that represents the brightness value at the image plane of the imaging lens. The luminance values ​​of the central and peripheral parts around the optical axis are calculated using the point image distribution function, and an evaluation function is formulated that represents the ratio of the luminance value of the peripheral part to the luminance value of the central part. The cross-sectional function of the depth-of-focus extension lens is determined by numerically calculating a predetermined coefficient such that the ratio of the luminance values ​​calculated by the evaluation function is minimized in a predetermined range around the focusing position. A method for designing microscope lenses that extend the depth of field, including [specific feature / method].

[0089] [Aspect 2] The cross-sectional shape of the depth-of-focus extension lens is rotationally symmetric with respect to the optical axis and is defined by a polynomial. A method for designing a microscope lens as described in Embodiment 1.

[0090] [Aspect 3] The aforementioned polynomial is a polynomial of degree 4. A method for designing a microscope lens as described in Embodiment 2.

[0091] [Aspect 4] To optimize the predetermined coefficients, the calculation process of the optimization method is executed. A method for designing a microscope lens according to any one of embodiments 1 to 3.

[0092] [Aspect 5] The computational process of the aforementioned optimization method is the global optimization method ADAM. A method for designing a microscope lens as described in Embodiment 4.

[0093] [Aspect 6] In calculating the wave function of light, Calculation of the first wave function generated from a sample positioned on the opposite side of the objective lens from the imaging lens, Based on the first wavefunction, the calculation of the second wavefunction after transmission through the objective lens, Based on the second wavefunction, the third wavefunction after passing through the depth-of-focus extension lens is calculated, The calculation of the fourth wave function at the image plane after transmission through the imaging lens, based on the third wave function, is included. A method for designing a microscope lens according to any one of embodiments 1 to 5.

[0094] [Aspect 7] A method for manufacturing a depth-of-focus extension lens inserted between an objective lens and an imaging lens, The depth-of-focus extension lens is modeled using a cross-sectional function that represents the surface position in the optical axis direction, with the position of the cross-sectional shape in a direction perpendicular to the optical axis direction being a variable, using a predetermined coefficient. Around the focal position, the wave function of light irradiated from the object to be measured and reaching the image plane of the imaging lens via the objective lens and the depth of field extension lens is calculated, with the position in the optical axis direction and the position in a direction perpendicular to the optical axis direction around the focal position as variables. Based on the wave function, a point image distribution function representing the brightness value at the image plane of the imaging lens is calculated. The luminance values ​​of the central and peripheral parts around the optical axis are calculated using the point image distribution function, and an evaluation function is formulated that represents the ratio of the luminance value of the peripheral part to the luminance value of the central part. The cross-sectional function of the depth-of-focus extension lens is determined by calculating a predetermined coefficient by numerical calculation such that the ratio of the luminance values ​​calculated by the evaluation function is minimized in a predetermined range around the focusing position. A depth-of-focus extension lens is created based on the aforementioned cross-sectional function. This invention provides a method for manufacturing microscope lenses that extend the depth of field. [Explanation of Symbols]

[0095] 2. Objective lens 3. Imaging lens 4. Depth of Focus Extension Lens C image plane C n predetermined coefficient f0 focus position S Sample (object to be measured)

Claims

1. A method for designing a depth-of-focus extension lens to be inserted between an objective lens and an imaging lens, The depth-of-focus extension lens is modeled using a cross-sectional function that represents the surface position in the optical axis direction, with the position of the cross-sectional shape in a direction perpendicular to the optical axis direction being a variable, using a predetermined coefficient. The wave function of light emitted from the object to be measured, passing through the objective lens and the depth-of-focus extension lens to the image plane of the imaging lens, is calculated using the position in the optical axis direction and the position in a direction perpendicular to the optical axis direction as variables, around the focal position. Based on the wave function, calculate a point image distribution function that represents the brightness value at the image plane of the imaging lens. The luminance values ​​of the central and peripheral parts around the optical axis are calculated using the point image distribution function, and an evaluation function is formulated that represents the ratio of the luminance value of the peripheral part to the luminance value of the central part. The cross-sectional function of the depth-of-focus extension lens is determined by numerically calculating a predetermined coefficient such that the ratio of the luminance values ​​calculated by the evaluation function is minimized in a predetermined range around the focusing position. A method for designing microscope lenses that extend the depth of field, including [specific feature / method].

2. The cross-sectional shape of the depth-of-focus extension lens is rotationally symmetric with respect to the optical axis and is defined by a polynomial. A method for designing a microscope lens according to claim 1.

3. The aforementioned polynomial is a polynomial of degree 4. A method for designing a microscope lens according to claim 2.

4. To optimize the predetermined coefficients, the calculation process of the optimization method is executed. A method for designing a microscope lens according to any one of claims 1 to 3.

5. The computational process of the aforementioned optimization method is the global optimization method ADAM. A method for designing a microscope lens according to claim 4.

6. In calculating the wave function of light, Calculation of the first wave function generated from a sample positioned on the opposite side of the objective lens from the imaging lens, Based on the first wave function, the calculation of the second wave function after transmission through the objective lens, Based on the second wavefunction, the third wavefunction after passing through the depth-of-focus extension lens is calculated, This includes calculating the fourth wave function at the image plane after transmission through the imaging lens, based on the third wave function. A method for designing a microscope lens according to any one of claims 1 to 3.

7. A method for manufacturing a depth-of-focus extension lens inserted between an objective lens and an imaging lens, The depth-of-focus extension lens is modeled using a cross-sectional function that represents the surface position in the optical axis direction, with the position of the cross-sectional shape in a direction perpendicular to the optical axis direction being a variable, using a predetermined coefficient. Around the focal position, the wave function of light irradiated from the object to be measured and reaching the image plane of the imaging lens via the objective lens and the depth of field extension lens is calculated, with the position in the optical axis direction and the position in a direction perpendicular to the optical axis direction around the focal position as variables. Based on the wave function, a point image distribution function representing the brightness value at the image plane of the imaging lens is calculated. The luminance values ​​of the central and peripheral parts around the optical axis are calculated using the point image distribution function, and an evaluation function is formulated that represents the ratio of the luminance value of the peripheral part to the luminance value of the central part. The cross-sectional function of the depth-of-focus extension lens is determined by numerically calculating a predetermined coefficient such that the ratio of the luminance values ​​calculated by the evaluation function is minimized in a predetermined range around the focusing position. A depth-of-focus extension lens is created based on the aforementioned cross-sectional function. A method for manufacturing microscope lenses that extend the depth of field.

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