Graph card, evaluation device and method for adjusting and evaluating imaging optical system

Abstract

The invention provides an information graphic card, an evaluation device, and a method for adjusting and evaluating an imaging optical system, which can appropriately evaluate the imaging optical system without changing the graphic card. The graphic card (100) has a graphic card pattern (100p) for evaluating the imaging optical system. The graphic card pattern (100p) comprises a plurality of closed areas (110) with the same shape, and the outline of each closed area comprises two sides perpendicular to each other. Each of the plurality of closed regions (110) is configured from a bright portion having a circular shape and a dark portion surrounding the bright portion. The plurality of closed regions include a central closed region placed at the center (101) of the card pattern (100p) and a plurality of peripheral closed regions disposed radially from the center (101) on a concentric circle (150) centered on the center (101).

Description

Technical Field

[0001] The disclosure of this specification relates to a chart, a method for adjusting an imaging optical system, a method for evaluating an imaging optical system, and an evaluation device. Background Art

[0002] The imaging optical system used in optical devices such as microscopes and cameras is composed of a plurality of lenses, and these lenses are arranged as designed to fully exert their performance. Therefore, in the assembly step of the imaging optical system, it is evaluated whether the imaging optical system exerts the expected performance. If the performance is not fully exerted, it is determined that the lenses constituting the imaging optical system are not arranged as designed, and the eccentricity of the lenses and the lens intervals are adjusted.

[0003] As one of the methods for evaluating the imaging optical system in the assembly step, there is known a method using a flat plate (hereinafter referred to as a chart) formed with a predetermined pattern. In this method, the imaging optical system is evaluated based on the image of the chart formed by the imaging optical system as the evaluation object.

[0004] A chart used for evaluating an imaging optical system is described in, for example, Patent Document 1. Patent Document 1 describes a technique for calculating MTF from an image of an edge portion of a pattern using a chart.

[0005] In addition, among typical evaluation methods of an imaging optical system using a chart, in addition to a method using image contrast as described in Patent Document 1, a method using the shape of a pinhole image is also known.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2002-350285 Summary of the invention

[0009] Problems to be solved by the invention

[0010] In the evaluation of the imaging optical system based on the above two evaluation methods, dedicated charts are generally used respectively. Therefore, in order to comprehensively evaluate the imaging optical system using the two evaluation methods, it is necessary to switch the charts.

[0011] However, the chart used for evaluation requires a higher accuracy than the performance of the imaging optical system to be evaluated. When switching such a chart requiring high accuracy, even if each is manufactured with sufficiently high accuracy, the error between the charts makes it difficult to correctly evaluate the imaging optical system.

[0012] In view of the above-mentioned actual situation, an object of one aspect of the present invention is to provide a technology capable of appropriately evaluating an imaging optical system without replacing a chart.

[0013] Means for solving problems

[0014] A chart of one embodiment of the present invention has a chart pattern for evaluating an imaging optical system, wherein the chart pattern includes a plurality of closed areas having the same shape, wherein the outline of each closed area includes two sides perpendicular to each other, and wherein each of the plurality of closed areas is composed of a bright portion having a circular shape and a dark portion surrounding the bright portion, and wherein the plurality of closed areas include: a central closed area placed at the center of the chart pattern; and a plurality of peripheral closed areas arranged radially from the center on concentric circles centered on the center.

[0015] A method for adjusting an imaging optical system according to one embodiment of the present invention comprises the following steps: configuring the chart described in the above-mentioned embodiment so that a bright portion of a closed area set in the center of a chart pattern possessed by the chart is located on the optical axis of the imaging optical system; photographing the chart with an imaging element via the imaging optical system to obtain a camera image of the chart; generating a plurality of enlarged images obtained by enlarging portions of a plurality of closed areas included in the chart pattern based on the camera image, and displaying the enlarged images corresponding to different closed areas in a plurality of display areas arranged two-dimensionally, respectively; and adjusting the eccentricity of the imaging optical system, the inclination of an image plane formed by the imaging optical system, and the flatness of the image plane based on information displayed in the plurality of display areas.

[0016] Another embodiment of the method for adjusting an imaging optical system of the present invention includes the following steps: configuring the chart described in the above embodiment so that the bright portion of a closed area set in the center of a chart pattern possessed by the chart is located on the optical axis of the imaging optical system; photographing the chart with an imaging element via the imaging optical system to obtain a camera image of the chart; displaying images of multiple closed areas included in the chart pattern in the camera image; calculating evaluation results of the imaging optical system at each of the multiple closed areas based on the camera image; displaying the evaluation results at the corresponding closed areas near each of the images of the multiple closed areas; and adjusting the eccentricity of the imaging optical system, the inclination of the image plane formed by the imaging optical system, and the flatness of the image plane based on the displayed evaluation results.

[0017] A method for evaluating an imaging optical system according to one embodiment of the present invention comprises the following steps: configuring the chart described in the above-mentioned embodiment so that a bright portion of a closed area set in the center of a chart pattern possessed by the chart is located on the optical axis of the imaging optical system; photographing the chart with an imaging element via the imaging optical system to obtain a camera image of the chart; generating a plurality of enlarged images obtained by enlarging parts of a plurality of closed areas included in the chart pattern based on the camera image, and displaying the enlarged images corresponding to different closed areas in a plurality of display areas arranged two-dimensionally, respectively; and determining the necessity of adjusting the eccentricity of the imaging optical system, the inclination of an image plane formed by the imaging optical system, and the flatness of the image plane based on information displayed in the plurality of display areas.

[0018] Another embodiment of the method for evaluating an imaging optical system of the present invention includes the following steps: configuring the chart described in the above embodiment so that the bright portion of a closed area set in the center of the chart pattern of the chart is located on the optical axis of the imaging optical system; photographing the chart with an imaging element via the imaging optical system to obtain a camera image of the chart; displaying images of multiple closed areas included in the chart pattern in the camera image; calculating evaluation results of the imaging optical system at each of the multiple closed areas based on the camera image; displaying the evaluation results at the corresponding closed areas near each of the images of the multiple closed areas; and determining the necessity of adjusting the eccentricity of the imaging optical system, the inclination of the image plane formed by the imaging optical system, and the flatness of the image plane based on the displayed evaluation results.

[0019] An evaluation device according to one embodiment of the present invention comprises: a microscope including an imaging optical system; an imaging element that photographs a chart described in the above embodiment via the imaging optical system; and a processor that calculates evaluation results of the imaging optical system at each of a plurality of closed areas included in a chart pattern possessed by the chart based on an image of the chart captured by the imaging element, i.e., a photographic image, and determines whether the imaging optical system needs to be adjusted based on a plurality of evaluation results of the imaging optical system corresponding to the plurality of closed areas.

[0020] Effects of the Invention

[0021] According to the above aspect, it is possible to provide a technology that can appropriately evaluate the imaging optical system without replacing the chart. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a diagram illustrating a microscope system according to one embodiment of the present invention.

[0023] Figure 2This is a diagram of a picture card illustrating one embodiment of the present invention.

[0024] Figure 3 Yes Figure 1 The chart shown contains an enlarged view of the enclosed area.

[0025] Figure 4 It is photographed by an imaging optical system Figure 3 An example of an image obtained by closing the area shown.

[0026] Figure 5 It is a diagram for explaining the adjustment operation of the imaging optical system.

[0027] Figure 6 This is a flowchart showing an example of the procedure of the method for adjusting the imaging optical system according to the first embodiment.

[0028] Figure 7 This is an example of a screen displayed in the adjustment method of the imaging optical system according to the first embodiment.

[0029] Figure 8 It is magnified Figure 7 A plot of the contrast information is shown.

[0030] Fig. 9 This is an example of a screen displayed in the adjustment method of the imaging optical system according to the second embodiment.

[0031] Fig.10 This is an example of a screen displayed in the adjustment method of the imaging optical system according to the third embodiment.

[0032] Fig.11 This is an example of a screen displayed in the adjustment method of the imaging optical system according to the fourth embodiment.

[0033] Fig.12 This is a flowchart showing an example of the process of the evaluation method of the imaging optical system according to the fifth embodiment.

[0034] Fig.13 This is an example of a screen displayed in the evaluation method of the imaging optical system according to the fifth embodiment.

[0035] Fig.14 This is an example of a screen displayed in the evaluation method of the imaging optical system according to the sixth embodiment.

[0036] Description of Reference Numerals

[0037] 1Microscope system

[0038] 10. Microscope

[0039] 11 Objective lens

[0040] 20 Camera device

[0041] 30 Computer

[0042] 31 processors

[0043] 32 Memory

[0044] 40 Display

[0045] 41~49 display area

[0046] 100 picture cards

[0047] 100p card pattern

[0048] 101 Central

[0049] 110~119 Closed area

[0050] 120 pinholes

[0051] 130 Surrounding Area

[0052] 150~155 concentric circles

[0053] 210, 220, 230 images

[0054] 311~319Enlarged image

[0055] 411~419 images

[0056] C. C1 to C9 contrast information

[0057] E, E1~E9 shape information DETAILED DESCRIPTION

[0058] Figure 1 This is a diagram illustrating a microscope system according to one embodiment of the present invention. Figure 1 The microscope system 1 shown is a system for evaluating an imaging optical system using a chart 100 , and includes a microscope 10 , an imaging device 20 , a computer 30 , and a display 40 .

[0059] The microscope 10 includes an imaging optical system as an evaluation object. An imaging device 20 is installed on the lens barrel of the microscope 10. The imaging optical system projects an image of a chart 100 placed on the stage of the microscope 10 onto the imaging device 20. The imaging device 20 includes an imaging element, and acquires an image of the chart 100 (hereinafter referred to as a photographed image) by photographing the chart 100 through the imaging optical system of the microscope 10. The chart 100 has a chart pattern for evaluating the imaging optical system. Therefore, the performance of the imaging optical system between the chart 100 and the imaging device 20 is appropriately reflected in the photographed image.

[0060] The microscope 10 may be an upright microscope or an inverted microscope. In addition, in the microscope 10, either transillumination or epiillumination may be used. Hereinafter, the microscope 10 is described as an upright microscope that projects the image of the chart 100 onto the imaging device 20 using transillumination.

[0061] The computer 30 is, for example, a personal computer having a processor 31 and a memory 32. Since the performance of the imaging optical system is reflected in the captured image, the computer 30 processes the captured image obtained by the imaging device 20 and generates information useful for evaluating the imaging optical system. The computer 30 also causes the display 40 to display the generated information useful for evaluating the imaging optical system. These processes are performed by the processor 31 executing a program stored in the memory 32.

[0062] The user of the microscope system 1 evaluates the imaging optical system and determines whether the imaging optical system is properly assembled to exhibit designed performance by checking the information displayed on the display 40. If the user determines that the imaging optical system is not properly assembled, the user adjusts the imaging optical system.

[0063] The imaging optical system includes the objective lens 11 and other lenses (imaging lens, adapter lens, etc.) When the other lenses are sufficiently adjusted in advance, the objective lens 11 can be substantially evaluated by evaluating the imaging optical system.

[0064] Figure 2 This is a diagram of a picture card illustrating one embodiment of the present invention. Figure 3 Yes Figure 1 The chart shown contains an enlarged view of the enclosed area. Figure 4 It is photographed by an imaging optical system Figure 3 An example of an image obtained by closing the area shown. Figure 5 FIG. 1 is a diagram for explaining the adjustment operation of the imaging optical system. Figures 2 to 5 , a chart 100 used in the microscope system 1 is described.

[0065] The chart 100 includes a chart pattern 100p for evaluating an imaging optical system, and the chart pattern 100p can comprehensively evaluate the imaging optical system from two aspects: the contrast and the shape of the image. Figure 2 As shown, the chart pattern 100 p includes a plurality of closed areas 110 .

[0066] like Figure 2 and Figure 3As shown, the plurality of closed areas 110 each have the same shape including two vertical sides in the outline. The shape of the closed area 110 is a square in this example, but any shape may be a rectangle or a sector with two vertical sides as long as it has two vertical sides.

[0067] The two vertical sides that make up the contour are suitable for evaluating Figure 4 The contrast of the image 210 of the closed area 110 (the image 230 of the peripheral area 130 described later) shown in FIG. 1 can also be evaluated by processing by the computer 30, for example, Figure 4 The concentration distribution of the portion (line) spanning both sides of the image 230 shown is differentiated to calculate the LSF (Line Spread Function), and the MTF (Modulation Transfer Function) is calculated by Fourier transforming the LSF. In addition, as a method for evaluating the contrast of the image, the difference in the brightness values ​​of adjacent pixels in the X and Y directions may be squared and the accumulated value (Brenner gradient) may be used as an evaluation value.

[0068] In addition, if Figure 2 as well as Figure 3 As shown in FIG. 1 , it is preferred that the two vertical sides of the closed area 110 are inclined relative to the XY direction of the pixel arrangement of the captured image. The reason for this is that by differentiating the concentration distribution of multiple lines crossing the inclined side (edge) and synthesizing the obtained multiple LSFs, it is possible to calculate a synthetic LSF that virtually makes the sampling pitch finer. In addition, the inclination of the edge is not particularly limited, and is, for example, about 1.5° to 3°.

[0069] like Figure 3 As shown, each of the multiple closed areas 110 is composed of a pinhole 120 and a peripheral area 130 surrounding the pinhole 120. The pinhole 120 is an example of a bright portion having a circular shape. The pinhole 120 can be, for example, an opening (through hole) provided in the chart 100, and can be composed of a transmissive component that allows illumination light to pass through. The peripheral area 130 is an example of a dark portion surrounding the bright portion, and has the above-mentioned two vertical sides. The peripheral area 130 can be, for example, a shading component provided on the surface of the chart 100. In addition, the shading component is formed of a metal film. The thickness of the shading component is, for example, less than 0.1 μm, and does not have a substantial thickness.

[0070] The pinhole 120 as a bright part surrounded by the peripheral area 130 as a dark part is suitable for evaluating the shape of the image (pinhole image 220). In order to evaluate the shape of the image (pinhole image 220), for example, the direction ( Figure 4 The angle θ), the length of the tail ( Figure 4 ΔP) etc.

[0071] As described above, each closed area 110 in which the pinhole 120 is provided in the dark portion (peripheral area 130) having vertical edges (two sides) is suitable for both evaluation of the contrast of the image and evaluation of the shape of the pinhole image. Therefore, by using the chart 100, the imaging optical system can be comprehensively evaluated based on both the contrast and shape of the image. In addition, since the chart pattern 100p has a plurality of closed areas 110, the imaging optical system can be evaluated individually at each position corresponding to each closed area 110 in the field of view without moving the chart 100 relative to the imaging optical system.

[0072] And, if Figure 2 As shown, the multiple closed areas 110 include: a closed area 110 placed at the center 101 of the card pattern 100p (referred to as the central closed area); and multiple closed areas 110 (referred to as the peripheral closed areas) radially from the center 101 and arranged on concentric circles 150 centered on the center 101. That is, the card pattern 100p has multiple closed areas 110 (peripheral closed areas) on each circle (concentric circle 151, concentric circle 152, concentric circle 153, concentric circle 154, concentric circle 155) constituting the concentric circle 150 centered on the center 101, and the multiple closed areas 110 (peripheral closed areas) on each circle are arranged in the same orientation relative to the center 101 as the corresponding closed areas 110 (peripheral closed areas) on other circles. In this way, the plurality of closed areas 110 are arranged in the radial direction and the circumferential direction around the center 101 , and thus, by comparing the evaluations at positions corresponding to the respective closed areas 110 , it is possible to understand how the evaluations change in the radial direction and the circumferential direction.

[0073] By using the chart 100 having the chart pattern 100p, it is possible to comprehensively evaluate whether the imaging optical system exhibits the expected performance based on the contrast and shape of the image for each position in the field of view (more strictly speaking, the position corresponding to each closed area 110). During the evaluation, it is not necessary to replace the chart 100, so it is possible to avoid the adverse effects of errors and differences between the charts 100 on the evaluation. In addition, it is not necessary to move the chart 100 used to evaluate different positions in the field of view, so it is possible to avoid the influence of errors in position and inclination caused by movement. Furthermore, by comparing the evaluations of each position in the field of view, it is also possible to understand the deviation of the performance of the imaging optical system.

[0074] The user can also make adjustments required for the imaging optical system (objective lens 11) based on this information. Figure 5As shown, the eccentricity of the lens 14 fixed to the lens frame 15 can also be adjusted by using an adjustment rod to touch the lens group 16 from the hole 13 provided in the main body part 12 of the objective lens 11. In addition, the lens interval can also be adjusted by reassembling the objective lens 11. In this way, the imaging optical system can be adjusted to exert the designed performance.

[0075] In addition, in order to accurately evaluate the periphery of the optical system, it is preferred to specify the inclination direction of the chart pattern 100p and the radius D of the outermost concentric circle 155 constituting the concentric circle 150 so that the closed area is photographed around the four corners of the field of view of the camera device used (a rectangle obtained by projecting the camera element onto the object plane), that is, the closed area is arranged in the diagonal direction of the field of view of the camera device.

[0076] For example, when the aspect ratio of the imaging device 20 (imaging element) is 4:3, it is preferable to arrange the closed area 110 so that the closed area 110 is located around the four corners of the image card pattern 100p, regardless of whether the imaging device 20 is arranged in the longitudinal direction or the transverse direction. Thus, the field of view of the imaging device 20 can be accurately evaluated regardless of whether the imaging device 20 is arranged in the longitudinal direction or the transverse direction.

[0077] Specifically, if Figure 2 As shown, it is preferable that the closed area 110 is arranged in four inclined directions (±36° direction and ±54° direction) in addition to the longitudinal and lateral directions. Figure 2 Rectangles 20a and 20b respectively represent the field of view of the camera when the camera is arranged in the vertical direction and the horizontal direction. The chart 100 is configured such that closed areas 110 are arranged at the four corners of either of the rectangles 20a and 20b.

[0078] When the aspect ratio of the imaging device 20 (imaging element) is 1:1, the closed region 110 may be arranged in two oblique directions (±45° directions) in addition to the longitudinal and lateral directions.

[0079] Next, a more preferred structure of the chart pattern 100 p will be described. First, a preferred structure of the closed regions 110 included in the chart pattern 100 p will be described, and then a preferred structure of the intervals between the closed regions 110 will be described.

[0080] like Figure 3As shown, the pinhole 120 of each closed area 110 is preferably located near the center of gravity of the closed area 110. For example, it is preferred that the center of gravity of the closed area 110 is located inside the pinhole 120. In addition, the diameter of the pinhole 120 is preferably less than one-fifth of the short side of the closed area 110. That is, in the chart 100, when the diameter of the pinhole 120 is P and the length of the short side of the two vertical sides included in the outline of the closed area 110 is L1, it is preferred that the following conditional formula (1) is satisfied.

[0081] P≤L1 / 5···(1)

[0082] Since the pinhole 120 is located near the center of gravity of the closed area 110 and the conditional expression (1) is satisfied, the imaging optical system can be more appropriately evaluated from both the contrast and shape of the image by using the chart 100 .

[0083] Although the pinhole 120 is surrounded by the peripheral area 130, if the adjustment of the imaging optical system is insufficient, for example Figure 4 As shown, the shape of the image 220 of the pinhole 120 is deformed. At this time, in order to correctly recognize the shape of the image 220 of the pinhole 120, it is preferable that the image 220 of the pinhole 120 is contained within the image 230 of the peripheral area 130 which is a dark portion. This is because if the image 220 exceeds the image 230, it is difficult to correctly grasp the shape of the pinhole image 220, and thus the sensitivity to the under-adjustment (e.g., decentering, etc.) of the imaging optical system is reduced.

[0084] If the pinhole 120 is located at a position greatly offset from the center of gravity of the closed area 110, the image 220 of the pinhole 120 is likely to protrude from the image 230 of the peripheral area 130, which is not preferable. In addition, even if the pinhole 120 is located near the center of gravity of the closed area 110, if the pinhole 120 is too large relative to the closed area 110, the image 220 of the pinhole 120 is likely to protrude from the image 230 of the peripheral area 130, which is not preferable. Therefore, in order to appropriately evaluate the shape of the image 220 of the pinhole 120, it is preferable that the pinhole 120 is located near the center of gravity of the peripheral area 130 and satisfies the conditional expression (1).

[0085] In addition, if the image 220 of the pinhole 120 protrudes from the image 230 of the peripheral area 130, there is a possibility that the contrast evaluation of the edge of the peripheral area 130 is adversely affected. Therefore, in order to appropriately evaluate the contrast of the image 230 of the peripheral area 130, it is also preferable that the pinhole 120 is located near the center of gravity of the peripheral area 130 and satisfies the conditional expression (1).

[0086] The conditional expression (1) indicates a condition that the pinhole 120 is not too large relative to the peripheral area 130 , but it is also undesirable that the pinhole 120 is too small relative to the peripheral area 130 .

[0087] The pinhole 120 preferably has a size such that the shape of the image 220 of the pinhole 120 magnified by the imaging optical system can be visually recognized. That is, it is preferred that a user who observes the image 220 of the pinhole 120 can recognize the degree of deviation from the circular shape. In addition, the diameter of the pinhole 120 is preferably at least larger than the resolution (Rayleigh resolution, Abbe resolution, Hopkins resolution, etc.) of the imaging optical system. Specifically, when the wavelength of light used for the evaluation of the imaging optical system is set to λ and the numerical aperture on the object side of the imaging optical system is set to NA, the chart 100 preferably satisfies the following conditional equation (2). It should be noted that when the evaluation is performed by visual observation by a person, since visible light (400nm to 700nm) is used, the wavelength λ is, for example, 550nm, which has a high relative visibility.

[0088] P ≥ 1·5×λ / NA···(2)

[0089] By making it possible to visually recognize the image 220 of the pinhole 120 and satisfying the conditional expression (2), the image forming optical system can be more appropriately evaluated based on the shape of the pinhole image using the chart 100 .

[0090] For example, in the case of evaluating an objective lens of NA 0.70, as an example, the closed region 110 of the chart 100 may be configured to have the following dimensions.

[0091] Pinhole diameter P = 2 μm

[0092] The length of both sides L = 30 μm (= L1 = L2)

[0093] It is preferred that the closed area 110 is smaller than one tenth of the maximum image height evaluated using the chart pattern 100p. Furthermore, it is preferred that there is a gap between the closed areas 110 adjacent in the image height direction (radial direction) to a degree that at least another closed area 110 can enter. That is, when the length of the longer side of the two vertical sides included in the outline of the closed area 110 is set to L2, the radius of the outermost concentric circle 155 constituting the concentric circle 150 is set to D, and the minimum gap between the closed areas 110 adjacent in the radial direction of the concentric circle 150 is set to G, the chart 100 preferably satisfies the following conditional expressions (3) and (4).

[0094] L2≤D / 10···(3)

[0095] G≥L2···(4)

[0096] The evaluation of the imaging optical system is often performed with an image height ratio of 0.1. When the size of the closed area 110 is larger than one tenth of the maximum image height, the closed areas 110 arranged at positions corresponding to the image height of 0.1 may overlap each other. Therefore, in order to correctly evaluate each image height, it is preferable to satisfy conditional expression (3).

[0097] In addition, if the closed area 110 itself is too large, it is difficult to regard the four corners of the closed area 110 as points of the same image height. In particular, when the gap between the closed areas 110 adjacent in the radial direction is small, and the gap is smaller than the length of the closed area 110 (for example, the diagonal length, L2, etc.), it is difficult to say that it is appropriate to treat the evaluation of the imaging optical system at each closed area 110 as an evaluation at a specific image height. Therefore, it is preferable to satisfy both conditional expressions (3) and (4).

[0098] In the following, in each embodiment, a specific example of an adjustment method and an evaluation method of an imaging optical system using the above-mentioned chart 100 will be described.

[0099] <First Embodiment>

[0100] Figure 6 This is a flowchart showing an example of the procedure of the method for adjusting the imaging optical system according to the present embodiment. Figure 7 This is an example of a screen displayed in the adjustment method of the imaging optical system according to the present embodiment. Figure 8 It is magnified Figure 7 A plot of the contrast information is shown.

[0101] In the adjustment method of the imaging optical system of this embodiment, Figure 6 As shown, first, the chart 100 is arranged on the stage of the microscope system 1 (step S1). Here, the chart 100 is arranged so that the pinhole 120 in the closed area 110 provided in the center 101 of the chart pattern 100p is located on the optical axis of the imaging optical system. This arrangement can be performed manually by the user of the microscope system 1, or automatically by the electric part of the microscope system 1.

[0102] Next, the microscope system 1 captures the chart 100 with the imaging device 20 via the imaging optical system to obtain a captured image of the chart 100 (step S2). Then, the microscope system 1 displays an image of the closed area 110 on the display 40 based on the captured image obtained in step S2 (step S3).

[0103] In step S3, the microscope system 1 first generates a plurality of magnified images (magnified images 311 to 319) by magnifying parts of the plurality of closed areas 110 included in the chart pattern 100p based on the captured image. The plurality of magnified images can be generated by selecting two or more closed areas 110 from all the closed areas 110 included in the chart pattern 100p. For example, each magnified image is generated by cutting out a part of the closed area 110 from the captured image and magnifying the part.

[0104] Afterwards, if Figure 7As shown, the microscope system 1 displays a plurality of magnified images (magnified images 311 to 319) on the screen 40a of the display 40. More specifically, the microscope system 1 displays magnified images corresponding to different closed areas in a plurality of display areas (display areas 41 to 49) arranged two-dimensionally on the screen 40a of the display 40. The magnified image may be displayed on the display 40 at a display magnification higher than the magnification when the entire captured image is displayed on the display 40.

[0105] Which enlarged image is displayed in which display area is determined according to the positional relationship between the display area and the closed area. That is, step S3 includes the following steps: determining the enlarged images to be displayed in the plurality of display areas respectively according to the positional relationship between the display area and the closed area.

[0106] Specifically, the microscope system 1 is Figure 7 The center display area 45 of the nine display areas shown may display an enlarged image 315 corresponding to the central closed area placed at the center 101 of the chart pattern 100p (or an enlarged image corresponding to the peripheral closed area close to the central closed area). Figure 7 In the remaining 8 display areas shown, the display areas located in the upper, lower, left, and right directions relative to the center can display the enlarged images corresponding to the peripheral closed areas located in the upper, lower, left, and right directions relative to the center 101. In the display areas located in the upper left, lower left, upper right, and lower right directions relative to the center, the enlarged images corresponding to the peripheral closed areas located in the upper left, lower left, upper right, and lower right directions relative to the center 101 can be displayed. In addition, Figure 7 The enlarged images 311 to 319 displayed in the display areas 41 to 49 respectively include Figure 2 The enclosed areas 111 to 119 are shown.

[0107] When step S3 is completed, the microscope system 1 calculates the evaluation results of the imaging optical system at each of the plurality of closed areas corresponding to the plurality of display areas based on the camera image obtained in step S2 (step S4). The evaluation results calculated in step S4 are, for example, information indicating the contrast of the enlarged image of the closed area (hereinafter referred to as contrast information).

[0108] When the evaluation result is calculated, the microscope system 1 displays the evaluation result calculated in step S4 on the screen 40a of the display 40 (step S5). Specifically, the microscope system 1 displays the evaluation result calculated in step S4 on the screen 40a of the display 40 (step S5). Figure 7 As shown, contrast information (contrast information C1 to contrast information C9 ) as evaluation results in corresponding closed areas are displayed in the plurality of display areas, respectively.

[0109] Contrast information C (a general term for contrast information C1 to contrast information C9) is, for example, Figure 8 The strip chart shown can intuitively grasp the contrast level. The strip chart displays, for example, the area R1 from 0 to the current value Vc of the contrast and the area R2 of the current value Vc and the peak value Vp in different colors. In addition, the peak value Vp is the peak value of the contrast in the corresponding closed area. For example, when evaluating the imaging optical system while focusing, the peak value Vp can be regarded as the contrast value in the best focusing state.

[0110] The execution order of the above steps S3 to S5 is not particularly limited. Figure 7 As shown, the enlarged images and evaluation results of the corresponding closed areas may be displayed in the plurality of display areas respectively.

[0111] After the magnified image and the evaluation result are displayed, the imaging optical system is adjusted according to the information (magnified image and contrast information) displayed in the plurality of display areas (step S6). More specifically, the user of the microscope system 1 adjusts the eccentricity of the imaging optical system, the inclination of the image plane formed by the imaging optical system, and the flatness of the image plane by adjusting the eccentricity of the lens of the imaging optical system and the lens interval.

[0112] According to the above description Figure 6 In the method for adjusting the imaging optical system using the chart 100 shown, the user can evaluate the shape of the pinhole image based on the enlarged image displayed on the display 40, and further evaluate the contrast of the image based on the contrast information displayed on the display 40. Therefore, the imaging optical system can be comprehensively evaluated based on the shape and contrast of the image, and necessary adjustments can be made to the imaging optical system.

[0113] In addition, the enlarged images and evaluation results of the corresponding multiple closed areas are displayed in the multiple display areas of the divided screen 40a. Since the enlarged images and evaluation results of the closed areas displayed in each display area are determined based on the positional relationship between the display area and the closed area, the user can understand at a glance how the performance of the imaging optical system changes within the field of view based on the information displayed in the multiple display areas.

[0114] <Second Embodiment>

[0115] Fig. 9 This is an example of a screen displayed in the imaging optical system adjustment method of this embodiment. The procedure of the imaging optical system adjustment method using the chart 100 of this embodiment is the same as that of the first embodiment except that the evaluation result calculated in step S4 and displayed in step S5 is different.

[0116] In this embodiment, in step S4, the microscope system 1 calculates, as an evaluation result, shape information indicating the shape of the pinhole image in addition to the contrast information of the enlarged image of the closed area corresponding to the evaluation result. The shape information indicating the shape of the pinhole image includes, for example, the direction in which the tail of the pinhole image extends (e.g. Figure 4 The angle θ) and the length of the tail of the pinhole image (e.g. Figure 4 length ΔP).

[0117] When the evaluation result is calculated in step S4, in step S5, the microscope system 1 displays the evaluation result calculated in step S4 on the display 40. Fig. 9 The screen 40b is different from the screen 40a of the first embodiment in that contrast information (contrast information C1 to contrast information C9) and shape information (shape information E1 to shape information E9) as evaluation results of corresponding closed areas are displayed in a plurality of display areas.

[0118] The shape information E (a general term for shape information E1 to shape information E9) may be any information that can intuitively grasp the degree of deterioration of the shape of the pinhole image, for example Fig. 9 In this case, the size (thickness, length) and color density of the arrow may indicate the length of the tail, and the direction of the arrow may indicate the direction of the tail.

[0119] According to the adjustment method of the imaging optical system of this embodiment, the user can also comprehensively evaluate the imaging optical system based on the shape and contrast of the image and make necessary adjustments as in the first embodiment. In particular, in this embodiment, in addition to the enlarged image (enlarged image 311 to enlarged image 319) displayed on the display 40, the shape of the pinhole image can also be evaluated based on the shape information (shape information E1 to shape information E9).

[0120] <Third Embodiment>

[0121] Fig.10 This is an example of a screen displayed in the imaging optical system adjustment method of this embodiment. The process of the imaging optical system adjustment method using the chart 100 of this embodiment is the same as that of the first embodiment except that the evaluation result calculation step S4 and the evaluation result display step S5 are omitted.

[0122] In this embodiment, the microscope system 1 displays on the display 40 Fig.10The user evaluates both the shape of the pinhole image and the contrast of the image based on the enlarged image displayed on the display 40. Therefore, according to the adjustment method of this embodiment, the imaging optical system can be comprehensively evaluated based on the shape and contrast of the image and necessary adjustments can be made.

[0123] <Fourth Embodiment>

[0124] Fig.11 This is an example of a screen displayed in the method for adjusting the imaging optical system of the present embodiment. The process of the method for adjusting the imaging optical system using the chart 100 of the present embodiment is the same as that of the second embodiment, except that the enlarged image is not displayed in step S3 but the image itself (image 411 to image 419) cut out from the captured image is displayed, and the evaluation result (contrast information C) is not displayed for each display area but for each image displayed in the display area in step S5.

[0125] In this embodiment, in step S3, the microscope system 1 displays images of multiple closed areas included in the chart pattern 100p in the captured image. Multiple images can be generated by selecting two or more closed areas 110 from all closed areas 110 included in the chart pattern 100p. For example, each image is generated by cutting out a portion of the closed area 110 from the captured image.

[0126] In this embodiment, in step S3, the microscope system 1 displays images of multiple closed areas included in the card pattern 100p in the camera image. Specifically, the microscope system 1 first selects two or more closed areas 110 from all the closed areas 110 included in the card pattern 100p, and cuts out parts of the selected closed areas 110 from the camera image to generate multiple images. Fig.11 As shown, the microscope system 1 displays different images (images 411 to 419) in a plurality of display areas (display areas 41 to 49) arranged two-dimensionally on the screen 40d of the display 40. Each image may contain at least one closed area or may contain a plurality of closed areas.

[0127] When step S3 is completed, the microscope system 1 calculates contrast information C and shape information E based on the camera image obtained in step S2 as evaluation results of the imaging optical system at each of the plurality of closed areas displayed in the plurality of display areas (step S4). In addition, the shape information E is an example of first evaluation information indicating the direction in which the bright part included in the image of the corresponding closed area extends and the length of the bright part, and the contrast information C is an example of second evaluation information indicating the contrast of the image of the corresponding closed area.

[0128] When the evaluation result is calculated in step S4, the microscope system 1 displays the evaluation result calculated in step S4 on the screen 40d of the display 40 (step S5). Fig.11 As shown, the microscope system 1 displays the evaluation results (contrast information C, shape information E) at the corresponding closed areas near each of the images of the multiple closed areas. That is, when the image contains multiple closed areas as in the image 411, the evaluation results of each closed area are displayed near the image of the closed area.

[0129] According to the adjustment method of the imaging optical system of the present embodiment, the user can also comprehensively evaluate the imaging optical system based on the shape and contrast of the image and make necessary adjustments, as in the above-mentioned embodiment. In addition, in the present embodiment, by displaying an image cut out from the camera image, it is possible to display more images of closed areas than when an enlarged image is displayed, thereby enabling the performance of a larger range within the field of view to be confirmed. In addition, by not using an enlarged image, it is difficult to grasp the shape of the pinhole image from the image compared to when an enlarged image is displayed, but by displaying the shape information E in addition to the image, it is possible to appropriately evaluate the shape of the pinhole image in the same manner as when an enlarged image is displayed.

[0130] In the first to fourth embodiments, an example is shown in which the user determines whether the imaging optical system needs to be adjusted while observing the screen displayed on the display 40, but the microscope system 1 may determine whether the imaging optical system needs to be adjusted, and the determination result may be displayed on the display 40. Hereinafter, an example is described in which the microscope system 1 operates as an evaluation device that determines whether the imaging optical system needs to be adjusted and displays the determination result.

[0131] <Fifth Embodiment>

[0132] Fig.12 This is a flowchart showing an example of the procedure of the evaluation method of the imaging optical system according to the present embodiment. Fig.13 This is an example of a screen displayed in the evaluation method of the imaging optical system according to the present embodiment.

[0133] In the evaluation method of the imaging optical system of this embodiment, if Fig.12As shown, first, the chart 100 is arranged on the stage of the microscope system 1 (step S11). Thereafter, the microscope system 1 obtains a camera image of the chart 100 (step S12), and based on the camera image, displays enlarged images corresponding to different closed areas in a plurality of display areas arranged two-dimensionally on the screen 40a of the display 40 (step S13). Furthermore, the microscope system 1 calculates the evaluation results of the imaging optical system at each of the plurality of closed areas corresponding to the plurality of display areas based on the camera image obtained in step S2 (step S14), and displays the evaluation results at the corresponding closed areas in the plurality of display areas based on the evaluation results calculated in step S4 (step S15). In addition, the processing of steps S11 to S15 is the same as the processing of steps S1 to S5 of the adjustment method of the imaging optical system of the second embodiment.

[0134] After that, the microscope system 1 determines whether the imaging optical system needs to be adjusted (step S16). Here, the microscope system 1 determines the necessity of adjusting the eccentricity of the imaging optical system, the inclination of the image plane formed by the imaging optical system, and the flatness of the image plane based on the information displayed in the plurality of display areas. The determination method is not particularly limited. For example, the eccentricity of the imaging optical system can be determined based on whether the evaluation results (contrast information C, shape information E) of each closed area converge within the allowable range of the expected performance. Furthermore, the inclination and flatness of the image plane of the imaging optical system can also be determined based on whether there is a deviation in the evaluation results of the closed areas within the field of view.

[0135] Finally, the microscope system 1 displays the determination result as to whether the imaging optical system needs to be adjusted (step S17). The method of displaying the determination result is not particularly limited, but the microscope system 1 may also display the determination result as follows, for example: Fig.13 As shown, a new window W1 including the determination result is popped up and displayed on the screen 40a of the display 40. In addition, the user may adjust the imaging optical system after confirming the determination result.

[0136] According to the evaluation method of the imaging optical system of the present embodiment, the microscope system 1 can comprehensively evaluate the imaging optical system based on the shape and contrast of the image, and determine whether the imaging optical system needs to be adjusted. In addition, the microscope system 1 evaluates the imaging optical system according to a fixed reference, thereby being able to perform adjustment operations based on whether the imaging optical system needs to be adjusted determined based on a fixed reference without relying on the user of the microscope system 1. In addition, the microscope system 1 displays the enlarged image of each closed area and the evaluation result on the screen 40a, so the user himself can confirm whether the determination made by the microscope system 1 is appropriate based on the enlarged image and the evaluation result. Therefore, the determination made by the microscope system 1 will not be black-boxed, so the user can accept the determination and adjust the imaging optical system as needed.

[0137] <Sixth Embodiment>

[0138] Fig.14 This is an example of a screen displayed in the imaging optical system evaluation method of this embodiment. The processing of steps S11 to S15 of the imaging optical system evaluation method using the chart 100 of this embodiment is the same as the processing of steps S1 to S5 of the imaging optical system adjustment method of the fourth embodiment.

[0139] Then, the microscope system 1 determines whether the imaging optical system needs to be adjusted (step S16), and displays the determination result on whether the imaging optical system needs to be adjusted (step S17). The method of displaying the determination result is not particularly limited, but the microscope system 1 may also display the determination result as follows, for example: Fig.14 As shown, a new window W2 including the determination result is popped up and displayed on the screen 40d of the display 40. In addition, the user may also adjust the imaging optical system after confirming the determination result.

[0140] According to the imaging optical system evaluation method of this embodiment, the microscope system 1 can also comprehensively evaluate the imaging optical system based on the shape and contrast of the image and determine whether the imaging optical system needs to be adjusted, similarly to the evaluation method of the fifth embodiment. In addition, the microscope system 1 evaluates the imaging optical system according to a fixed reference, so that the user can perform adjustment work based on whether the imaging optical system needs to be adjusted based on the fixed reference; and the user can confirm whether the determination made by the microscope system 1 is appropriate based on the image and the evaluation result, which is also the same as the fifth embodiment.

[0141] The above-mentioned embodiments show specific examples for easy understanding of the invention, and the present invention is not limited to these embodiments. It may include a deformation method after the above-mentioned embodiments are deformed and an alternative method replacing the above-mentioned embodiments. That is, each embodiment can deform the constituent elements within the scope of its purpose and scope. In addition, by appropriately combining multiple constituent elements disclosed in more than one embodiment, a new embodiment can be implemented. In addition, several constituent elements can be deleted from the constituent elements shown in each embodiment, or several constituent elements can be added to the constituent elements shown in the embodiment. Moreover, the processing procedures shown in each embodiment can also be performed in a reversed order as long as there is no contradiction.

[0142] In the above-mentioned embodiment, the chart 100 including one pinhole 120 in one closed area 110 is exemplified, but the chart for evaluating the imaging optical system may include a plurality of pinholes 120 in one closed area 110. In this case, the pinhole 120 also satisfies the conditional expression (1), but a stricter condition such as P≤L1 / 10 may be imposed on the diameter P of the pinhole 120 depending on the number of pinholes 120 included in the closed area 110.

[0143] In addition, the sizes of the plurality of pinholes 120 included in one closed area 110 may be the same or different. In different cases, the pinhole diameters may be set according to the specifications of the imaging optical system such as NA and magnification.

[0144] Furthermore, when a plurality of pinholes 120 are included in one closed region 110 , the bright portion corresponding to the pinholes 120 may not be located at the center of gravity of the closed region 110 .

[0145] In the above-mentioned embodiment, the chart 100 shows an example of having the pinhole 120 for transmitting light as a circular bright portion, but the bright portion is not limited to the pinhole 120. In a microscope system using epi-illumination, the chart may include a structure for reflecting light as a circular bright portion, or may be configured as a dark portion surrounding the bright portion through which light is transmitted.

[0146] In the above-mentioned embodiment, an example in which a plurality of closed areas 110 are arranged radially is shown, but they do not need to be arranged radially as long as they are arranged in a plurality of directions relative to the center 101. However, the radial arrangement is preferred in that the imaging optical system can be evaluated based on the evaluation results of a plurality of closed areas 110 arranged on different concentric circles for each direction.

[0147] In the above-described embodiment, an example is shown in which the same number of multiple closed areas 110 are arranged on each concentric circle. However, as long as multiple closed areas 110 are arranged on each concentric circle, the same number of closed areas 110 do not necessarily need to be arranged.

[0148] Although not particularly mentioned in the above-mentioned embodiment, the evaluation of the imaging optical system is preferably performed in a state where the image chart 100 is in focus. Figure 6 as well as Fig.12 The steps after image acquisition of the method shown can also be performed at each z position during focus adjustment. That is, image acquisition, evaluation calculation, image and evaluation result display can also be repeated in real time during focus adjustment. In addition, in this case, the contrast information C displayed in each display area can also be used to determine whether the focus is achieved.

[0149] In the above-mentioned embodiment, an example is shown in which the multiple display areas are of the same size, but the multiple display areas may also include display areas of different sizes. Fig.11 In the example shown, the display area 45 in which the range of the displayed image is relatively narrow may be configured to be smaller than the surrounding display areas. This allows the space in the screen 40d to be used more efficiently.

[0150] In this specification, the expression "based on A" does not mean "based only on A", but means "based at least on A", and also means "based at least partially on A". That is, "based on A" may be based on B in addition to A, or may be based on a part of A.

Claims

1. A chart having a chart pattern for evaluating an imaging optical system, characterized in that: The card pattern includes a plurality of closed areas having the same shape, and the outline of each closed area includes two sides perpendicular to each other. Each of the plurality of closed areas is composed of a bright portion having a circular shape and a dark portion surrounding the bright portion, The multiple closed areas include: a central enclosed area, which is placed in the center of the card pattern; and A plurality of peripheral closed areas are arranged radially from the center on concentric circles centered on the center.

2. The image card according to claim 1, characterized in that: The center of gravity of each of the plurality of closed areas is located within the bright portion, Satisfy the following conditions P≤L1 / 5···(1) Wherein, L1 is the length of the shorter side of the two sides included in the outline of the closed area, and P is the diameter of the bright part.

3. The picture card according to claim 2, characterized in that: Satisfy the following conditions P ≥ 1.5 × λ / NA (2) Here, λ is the wavelength of light used to evaluate the imaging optical system, and NA is the numerical aperture on the object side of the imaging optical system.

4. The picture card according to claim 1 or 2, characterized in that: Satisfy the following conditions L2≤D / 10···(3) G≥L2···(4) Among them, L2 is the length of the longer side of the two sides included in the outline of the closed area, D is the radius of the outermost circle constituting the concentric circles, and G is the minimum gap between the closed areas adjacent to each other in the radial direction of the concentric circles.

5. A method for adjusting an imaging optical system, characterized in that: The steps include: The chart of claim 1 is arranged so that a bright portion of a closed area provided at the center of the chart pattern possessed by the chart is located on the optical axis of the imaging optical system; photographing the picture card with a camera element via the imaging optical system to obtain a camera image of the picture card; generating a plurality of enlarged images by enlarging parts of a plurality of closed areas included in the card pattern according to the camera image, and displaying the enlarged images corresponding to different closed areas in a plurality of display areas arranged two-dimensionally; as well as The eccentricity of the imaging optical system, the inclination of an image plane formed by the imaging optical system, and the flatness of the image plane are adjusted according to the information displayed on the plurality of display areas.

6. The method according to claim 5, characterized in that The following steps are also included: calculating, based on the captured image, an evaluation result of the imaging optical system at each of a plurality of closed areas corresponding to the plurality of display areas; and The evaluation results at the corresponding closed areas are displayed in the plurality of display areas respectively.

7. The method according to claim 5 or 6, characterized in that: The step of displaying the enlarged image includes the step of determining the enlarged images to be displayed in the plurality of display areas, respectively, based on a positional relationship between the display area and the closed area.

8. A method for adjusting an imaging optical system, characterized in that: The steps include: The chart of claim 1 is arranged so that a bright portion of a closed area provided in the center of the chart pattern of the chart is located on the optical axis of the imaging optical system; photographing the picture card with a camera element via the imaging optical system to obtain a camera image of the picture card; Displaying images of a plurality of closed areas included in the card pattern in the camera image; calculating, based on the camera image, an evaluation result of the imaging optical system at each of the plurality of closed areas; displaying the evaluation result at the corresponding closed area near each of the images of the plurality of closed areas; as well as Based on the displayed evaluation result, the decentering of the imaging optical system, the inclination of the image plane formed by the imaging optical system, and the flatness of the image plane are adjusted.

9. The method according to claim 8, characterized in that The evaluation result includes first evaluation information and second evaluation information. The first evaluation information indicates a direction in which a bright portion included in the image of the corresponding closed area extends and a length of the bright portion. The second evaluation information indicates a contrast of an image of the corresponding closed area.

10. The method according to claim 8 or 9, characterized in that: The step of displaying the images of the plurality of closed areas includes the step of determining positions for displaying the images of the plurality of closed areas according to the positional relationship between the plurality of closed areas.

11. A method for evaluating an imaging optical system, characterized in that: The steps include: The chart of claim 1 is arranged so that a bright portion of a closed area provided in the center of the chart pattern of the chart is located on the optical axis of the imaging optical system; photographing the picture card with a camera element via the imaging optical system to obtain a camera image of the picture card; generating a plurality of enlarged images by enlarging parts of a plurality of closed areas included in the card pattern according to the camera image, and displaying the enlarged images corresponding to different closed areas in a plurality of display areas arranged two-dimensionally; as well as Based on the information displayed on the plurality of display areas, necessity of adjusting the decentering of the imaging optical system, the inclination of an image plane formed by the imaging optical system, and the flatness of the image plane is determined.

12. The method according to claim 11, characterized in that The following steps are also included: calculating, based on the captured image, an evaluation result of the imaging optical system at each of a plurality of closed areas corresponding to the plurality of display areas; and The evaluation results of the corresponding closed areas are displayed in the plurality of display areas respectively.

13. The method according to claim 11 or 12, characterized in that: The step of displaying the enlarged image includes the step of determining the enlarged images to be displayed in the plurality of display areas, respectively, based on a positional relationship between the display area and the closed area.

14. A method for evaluating an imaging optical system, characterized in that: The steps include: The chart of claim 1 is arranged so that a bright portion of a closed area provided in the center of the chart pattern of the chart is located on the optical axis of the imaging optical system; photographing the picture card with a camera element via the imaging optical system to obtain a camera image of the picture card; Displaying images of a plurality of closed areas included in the card pattern in the camera image; calculating, based on the camera image, an evaluation result of the imaging optical system at each of the plurality of closed areas; displaying the evaluation result at the corresponding closed area near each of the images of the plurality of closed areas; as well as Based on the displayed evaluation results, necessity of adjusting the decentering of the imaging optical system, the inclination of the image plane formed by the imaging optical system, and the flatness of the image plane is determined.

15. The method according to claim 14, characterized in that The evaluation result includes first evaluation information and second evaluation information. The first evaluation information indicates a direction in which a bright portion included in the image of the corresponding closed area extends and a length of the bright portion. The second evaluation information indicates a contrast of an image of the corresponding closed area.

16. The method according to claim 14 or 15, characterized in that The step of displaying the images of the plurality of closed areas includes the step of determining positions for displaying the images of the plurality of closed areas according to the positional relationship between the plurality of closed areas.

17. An evaluation device, characterized in that: have: a microscope comprising an imaging optical system; an imaging element that captures the image card according to claim 1 via the imaging optical system; and processor, The processor calculates the evaluation result of the imaging optical system at each of a plurality of closed areas included in a chart pattern of the chart based on the image of the chart captured by the imaging element, that is, the captured image. The processor determines whether the imaging optical system needs to be adjusted based on a plurality of evaluation results of the imaging optical system corresponding to the plurality of closed areas.

18. The evaluation device according to claim 17, characterized in that The evaluation result includes first evaluation information and second evaluation information. The first evaluation information indicates a direction in which a bright portion included in the image of the corresponding closed area extends and a length of the bright portion. The second evaluation information indicates a contrast of an image of the corresponding closed area.

Images