JP2015184544A - Catadioptric optical system and imaging device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a catadioptric optical system that corrects various aberrations over a broad wavelength and a broad filed of view area, and is resistant against even a deviation of an image pickup element in an optical direction.SOLUTION: A catadioptric optical system comprises, in order from an object side to an image side: a first optical element (M1) that has a first light transmission unit (M1T) transmitting light from an object in a first area including an optical axis, and a first light reflection unit (M1R) reflecting the light in a surface on the object side of a second area further away from the optical axis than the first area; and a second optical element (M2) that has an aperture stop (AS), a second light transmission unit (M2T) transmitting the light in a third area including the optical axis, and a second light reflection unit (M2R) reflecting the light in a surface on the image side of a fourth area further away from the optical axis than the third area. The aperture stop is configured to be arranged at a position where an angle formed with a principal ray of a principal wavelength of light incident upon the image surface and the optical axis is equal to or less than 0.5°.

Description

  The present invention relates to a catadioptric optical system, and more particularly to a catadioptric optical system used when a sample (object) is magnified and observed.

  In recent years, a so-called virtual microscope that takes a pathological specimen as image data and observes it on a display has been used. In a virtual microscope, image data of a pathological specimen can be observed on a display, so that a plurality of persons can observe it simultaneously. In addition, the use of this virtual microscope has many advantages such as sharing image data with a distant pathologist for diagnosis. However, this method has a problem that it takes time to capture a pathological specimen and capture it as image data.

  One of the causes of time consuming is that a pathological specimen in a large imaging range must be captured as image data using a narrow imaging region of a microscope. When the imaging area of the microscope is small, it is necessary to capture a plurality of times or to capture a single image by connecting the images while scanning. An optical system (imaging optical system) having a wide imaging area is required in order to reduce the number of times of imaging than before and to shorten the time for capturing image data.

  In addition to this, when observing a pathological specimen, a wide imaging region is required, and at the same time, an optical system having a high resolving power in the visible region (wide wavelength region) is desired. Optical systems having high resolving power are required not only for pathological diagnosis but also in various fields. A microscope objective lens suitable for observation of a living cell or the like that is composed of a refractive optical system and has excellent aberrations reduced over the entire visible light region is known (Patent Document 1).

  In addition, there is known an ultra-wideband ultraviolet microscope imaging system having a high resolving power over a wide ultraviolet wavelength band using a catadioptric optical system for inspecting defects existing in an integrated circuit or a photomask (Patent Document 2). ). Further, a catadioptric optical system suitable for manufacturing a semiconductor element by exposing a fine pattern over a wide area is known (Patent Document 3).

Japanese Examined Patent Publication No. 60-034737 Special table 2007-514179 gazette International Publication No. 00/039623

  Although the microscope objective lens disclosed in Patent Document 1 reduces various aberrations well over the entire visible light region, the size of the observation region is not always sufficient. Moreover, although the wide-band microscope catadioptric imaging system disclosed in Patent Document 2 reduces aberrations well over a wide wavelength band and has high resolution, the size of the field of view is not always sufficient.

  Further, the catadioptric imaging optical system disclosed in Patent Document 3 has high resolution over a wide area, but the width of the wavelength range in which aberrations are well corrected is not necessarily sufficient.

  A microscope lens for enlarging and observing a sample is required to have a large observation region and high optical performance over a wide wavelength range. Further, it is desirable that the imaging apparatus has a characteristic that the magnification does not change even when an imaging element for capturing an image is displaced in the optical axis direction.

  The present invention provides a catadioptric optical system that corrects various aberrations satisfactorily over a wide wavelength range and a wide visual field range and that is resistant to displacement in the optical axis direction of an image sensor, and an imaging apparatus having the same. With the goal.

  The catadioptric optical system according to one aspect of the present invention includes, in order from the object side to the image side, a first light transmission unit that transmits light from the object in the first region including the optical axis, and the first region. A first optical element having a first light reflecting portion that reflects the light on the object-side surface of the second region away from the optical axis, an aperture stop, and a third region including the optical axis. A second optical transmission unit including: a second optical transmission unit configured to transmit the light; and a second optical reflection unit configured to reflect the light on the image-side surface of the fourth region farther from the optical axis than the third region. And the aperture stop is arranged at a position where an angle formed between a principal ray of a principal wavelength of light incident on an image plane and the optical axis is 0.5 degrees or less. .

  Other objects and features of the present invention are illustrated in the following examples.

  According to the present invention, it is possible to obtain a catadioptric optical system that corrects various aberrations satisfactorily over a wide wavelength region and a wide field of view, and that is resistant to displacement of the image sensor in the optical axis direction.

It is a schematic sectional drawing of the imaging device common to all the Examples of this invention. 1 is a schematic diagram of a main part of a catadioptric optical system of Example 1. FIG. FIG. 3 is an aberration diagram of the catadioptric optical system of Example 1. FIG. 6 is a schematic diagram of a main part of a catadioptric optical system of Example 2. FIG. 6 is an aberration diagram of the catadioptric optical system of Example 2.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same members are denoted by the same reference numerals, and redundant description is omitted.

  The catadioptric optical system 104 of the present invention includes a first imaging optical system G1 including a catadioptric unit that collects a light beam from an object (sample) 103 and forms an intermediate image IM of the object, and an intermediate image IM. And a second imaging optical system G2 including a refracting part that forms an image on the surface (imaging element surface) 105. The imaging apparatus 1000 of the present invention includes a light source 101, an illumination optical system 102 that illuminates an object 103 with a light beam from the light source 101, and a catadioptric optical system 104 that forms an image of the object 103. Further, the image pickup apparatus 1000 is generated by an image pickup element 105 that photoelectrically converts an object image formed by the catadioptric optical system 104, an image processing system 106 that generates image data from data from the image pickup element 105, and an image processing system 106. Display means 107 for displaying image data.

  In the first imaging optical system G1 constituting the catadioptric optical system 104 of the present invention, the central part around the optical axis is a light transmitting part, and a reflecting film is provided on the object side surface in the peripheral part around the central part. And has a first optical element M1 as a back-surface reflecting portion. Further, a central portion around the optical axis has a light transmitting portion, and a second optical element M2 is formed by applying a reflective film to the image-side surface of the peripheral portions around the central portion to form a back reflecting portion.

  Further, the catadioptric optical system 104 has an aperture stop AS in the optical path between the first optical element M1 and the second optical element M2. Here, the aperture stop AS may be provided on the second imaging optical system G2 side. The position of the aperture stop AS on the optical axis is determined so that the angle formed by the principal ray of the principal wavelength incident on the image plane on the magnification side (image side) and the optical axis is 0.5 degrees or less.

FIG. 1 is a schematic diagram of a main part of an imaging apparatus according to the present invention. FIG. 2 is a schematic view of the essential portions of Embodiment 1 of the catadioptric optical system of the present invention. FIG. 3 is an aberration diagram of Example 1 of the catadioptric optical system of the present invention. FIG. 4 is a schematic view of the essential portions of Embodiment 2 of the catadioptric optical system of the present invention. FIG. 5 is an aberration diagram of Example 2 of the catadioptric optical system of the present invention.
[Example 1]
Hereinafter, the configuration of the imaging apparatus 1000 having the catadioptric optical system 104 of the present invention will be described in detail with reference to FIG. Here, FIG. 1 is a schematic sectional view of an imaging apparatus 1000 according to the present invention. The imaging apparatus 1000 condenses the light from the light source 101 by the illumination optical system 102 and uniformly illuminates the sample (object) 103. The light used at this time is visible light (for example, wavelength 400 nm to wavelength 700 nm). Visible light only needs to contain a light beam in the wavelength range of 486 nm to 656 nm. The catadioptric optical system 104 forms an image of the sample (object) 103 on the image sensor 105. In other words, the imaging apparatus 1000 includes a light source 101 that emits visible light, an illumination optical system 102 that illuminates the object 103 with light from the light source, a catadioptric optical system 104 that receives light from the object, An image sensor 105 that photoelectrically converts light emitted from the catadioptric optical system. The image processing system 106 generates image data based on data (image information) acquired by the image sensor 105. The generated image data is displayed on the display means 107 or the like. In addition, the generated image data may be recorded on a recording medium (recording unit) (not shown). In the image processing system 106, aberrations that cannot be corrected by the catadioptric optical system 104 are corrected, or image data with different imaging positions (imaging regions) are connected to be combined into a single piece of image data. Processing according to the application is performed.

  FIG. 2 is a schematic diagram for explaining the configuration of the catadioptric optical system 104 of FIG. 2, 104A (104B in another embodiment) is a catadioptric optical system, 103 is an object plane on which an object (sample) is arranged, and 105 is an image plane on which an image sensor is arranged. AX is the optical axis of the catadioptric optical system 104A.

  The catadioptric optical system 104A has a first imaging optical system G1 that includes the reflecting surfaces M1R and M2R that condense the light beam from the object 103 and form an intermediate image IM on a predetermined surface, and an aperture stop AS.

  A field lens portion FL is disposed at a position where the intermediate image IM is formed. The field lens unit FL efficiently guides the light beam from the intermediate image IM to the second imaging optical system G2. The field lens portion FL may be omitted.

  The catadioptric optical system 104 </ b> A includes a second imaging optical system G <b> 2 including a refractive surface that forms the intermediate image IM on the image plane 105.

  The first imaging optical system G1 includes, in order from the object side, a first optical element (Mangin mirror) M1, an aperture stop AS, and a second optical element (Mangin mirror) M2.

  FIG. 2 shows a light flux from the object plane 103 to the image plane 105. The first optical element M1 of the first imaging optical system G1 has a surface M1a on the object 103 side having a convex shape and a vicinity of the optical axis (that is, a first region including the optical axis of the catadioptric optical system, in other words, the center. Part) is formed of a light transmission part M1T (first light transmission part) having a positive refractive power. In addition, a reflective film M1R (first light reflecting portion) is applied to the object-side surface M1a in the peripheral portion (that is, the second region away from the optical axis (outside) from the first region) to form a back surface reflecting portion. Yes. The surface M1a has an aspherical shape. M1b is an image side surface of the first optical element M1.

  The second optical element M2 has a meniscus shape with a concave surface directed toward the object side, and light having a negative refractive power in the vicinity of the optical axis (that is, the third region including the optical axis of the catadioptric optical system, in other words, the central portion). The transmission part M2T (second light transmission part) is formed. In addition, a reflective film M2R (second light reflecting portion) is applied to the image-side surface M2b of the peripheral portion (that is, the fourth region away from the optical axis (outside) than the third region) to form a back surface reflecting portion. Yes. M2a is the object side surface of the second optical element M2. The surface M2b has an aspheric shape. The first optical element M1 and the second optical element M2 are arranged so that the back surface reflecting portions M1R and M2R face each other. An aperture stop AS is disposed between the first optical element M1 and the second optical element M2.

  In other words, the catadioptric optical system 104A includes the first optical element M1, the aperture stop AS, and the second optical element M2 in order from the object plane to the image plane. In the first optical element M1, a first light transmission portion M1T that transmits light from the object 103 disposed on the object plane is formed in a first region including the optical axis AX. In addition, a first light reflecting portion M1R that reflects light from an object is formed on the object-side surface M1a of the second region that is further away from the optical axis than the first region. In the second optical element M2, a second light transmission portion M2T that transmits light from the object 103 is formed in a third region including the optical axis AX. A second light reflecting portion M2R that reflects light from the object is formed on the image-side surface M2b of the fourth region that is further away from the optical axis than the third region.

  In the catadioptric optical system 104A shown in FIG. 2, the light beam illuminated from the illumination optical system 102 and emitted from the object 103 passes through the central transmission part M1T of the first optical element M1. Thereafter, the light passes through the aperture stop AS and enters the refractive surface M2a of the second optical element M2. Thereafter, the light is reflected and condensed by the back surface reflection portion M2R, passes through the refractive surface M2a and the aperture stop AS, and enters the refractive surface M1b of the first optical element M1. Then, it reflects with the back surface reflection part M1R of the 1st optical element M1. Then, the light passes through the refractive surface M1b and the aperture stop AS, passes through the central transmission part M2T of the second optical element M2, and exits toward the second imaging optical system G2. Thereafter, an intermediate image IM of the object 103 is formed in the vicinity of the field lens portion FL.

  In this embodiment, the intermediate image IM may be formed without the field lens portion FL. The divergent light beam from the intermediate image IM passes through the second imaging optical system G2 composed of a plurality of lenses and enters the image plane 105. Then, the image of the object 103 is enlarged on the image plane 105. The image of the object 103 formed on the image sensor 105 is processed by the image processing system 106 and displayed on the display unit 107.

  The characteristics of the first imaging optical system G1 that forms the intermediate image IM of this embodiment will be described. An aperture stop AS is disposed between the optical paths of the first optical element M1 made of a Mangin mirror and the second optical element M2 made of a Mangin mirror. Accordingly, the position of the aperture stop AS is determined so that the telecentricity is completely satisfied on the image plane 105 side. In this embodiment, the aperture stop AS is disposed at a position closer to the first optical element M1 than to the second optical element M2. In the present invention, “telecentricity is completely satisfied on the image plane 105 side” means that the angle formed with the optical axis when the principal ray at the principal wavelength is incident on the image plane 105 is 0. It means that it is 5 degrees or less. In other words, the aperture stop AS is disposed at a position where the angle formed between the principal ray of the principal wavelength of light incident on the image plane 105 on the image side and the optical axis is 0.5 degrees or less. In order to completely satisfy telecentricity, it is preferable that the aperture stop AS has an angle formed between the principal ray of the principal wavelength of light incident on the image plane 105 on the image side and the optical axis is 0.1 degrees or less. It is good to arrange at the position. More preferably, the position of the aperture stop AS is at a position where the angle formed by the principal ray of the principal wavelength of light incident on the image plane 105 on the image side and the optical axis is 0.05 degrees or less. The principal ray is assumed to be a ray that goes out from the object point and passes through the center of the aperture stop AS. Since this optical system is an optical system with a central shield, there is actually no light beam passing through the center of the aperture stop, but it can be virtually considered and calculated. In the first imaging optical system G1, the light beam passes through the position of the aperture stop AS a total of three times, but the AS functions as an aperture stop that restricts the light beam during the second pass. . Therefore, the light beam passing through the center of the aperture stop AS described above is the one when the AS passes the second time. In the present embodiment, the dominant wavelength is a wavelength within the range of visible light wavelengths. As used herein, the dominant wavelength refers to the wavelength of the most contained light among the light incident on the image plane 105. Specifically, the dominant wavelength is 587.6 nm of d-line, but an appropriate dominant wavelength may be selected depending on the purpose.

  By completely satisfying the telecentricity on the image plane side, light can be incident on the image sensor 105 perpendicularly, so that the aperture ratio of the image sensor becomes uniform in the entire area on the image plane. An image can be obtained. Further, since the magnification does not change even when the image sensor 105 is largely displaced in the optical axis direction, a high quality image can be obtained. Furthermore, it is possible to introduce only a spherical aberration (and axial chromatic aberration) in the entire area on the image plane by inserting a plane-parallel plate between the second imaging optical system G2 and the image sensor 105. In other words, a plane parallel plate may be disposed on the image side with respect to the second imaging optical system G2. This plane-parallel plate can be used for thickness correction of the cover glass.

  If the telecentricity on the image plane side is not perfect, in other words, if the angle formed by the optical axis when the chief ray at the principal wavelength is incident on the image plane 105 exceeds 0.5 degrees, Depending on the location, the aperture ratio varies, which is not preferable from the viewpoint of high quality images. In addition, since the magnification changes when the image sensor 105 is largely displaced in the optical axis direction, it is not preferable from the viewpoint of a high-quality image. In addition, if a plane-parallel plate is inserted between the second imaging optical system G2 and the image sensor 105, field curvature occurs, so that it cannot be used for applications in which only the plane aberration is changed by inserting a plane-parallel plate.

  In this embodiment, when the absolute value of the lateral magnification of the catadioptric optical system 104A is β, the angle formed by the principal wavelength of the principal wavelength emitted from the object plane on the reduction side (object side) and the optical axis is β degrees. The aperture stop position is set so as to be as follows. In other words, when the absolute value of the lateral magnification of the catadioptric optical system 104A is β, the position of the aperture stop AS is the angle between the principal ray of the principal wavelength of the light emitted from the object on the object side and the optical axis is β It is in the position where it is below

  As a result, the change in magnification when the object plane is displaced in the optical axis direction can be kept relatively small. If it exceeds β degrees, the change in magnification is conspicuous, which is not preferable from the viewpoint of a high-quality image.

  In this embodiment, the aperture stop AS is a variable stop whose diameter can be changed.

  This makes it possible to control the resolution or depth of focus, and to select the resolution or depth of focus that suits the purpose and measurement target.

  The catadioptric optical system of the present embodiment has a visual field area of φ (diameter) of 3 mm or more when a numerical example described later is expressed in mm. If the field of view area (imaging area) is less than this, it is not preferable because the number of times of imaging when the entire object plane is divided and imaged increases, and the time taken for the entire imaging becomes longer.

  By setting the field of view to φ3 mm or more, the number of division imaging is reduced, so that the imaging time can be easily reduced. Further, it is more preferable that the visual field area is φ10 mm or more, and batch imaging of the object surface becomes easy, so that the imaging time can be greatly shortened.

  In the present embodiment, the reflecting portions on the back surfaces of the first and second optical elements M1 and M2 are both concave and aspheric. By using two aspheric shapes in this way, the occurrence of various aberrations such as spherical aberration and coma aberration is suppressed without increasing chromatic aberration.

  In the catadioptric optical system 104A of Example 1, the numerical aperture on the object side is 0.7, the magnification is 7.97 times, the object height is 7.2 mm, and the viewing area is φ14.4 mm. The visual field region satisfies φ3 mm or more and also satisfies φ10 mm or more.

  The angle formed by the optical axis of the principal ray at the principal wavelength (587.6 nm) is 0.6 degrees or less on the object plane and 0.03 degrees or less on the image plane. Further, the wavefront aberration in white light covering the visible wavelength range of 486 nm to 656 nm is suppressed to 50 mλrms or less.

  FIG. 3 shows lateral aberrations on the image plane (imaging device surface) of Example 1, and the aberrations are well corrected in a wide wavelength band in the visible range both on and off the axis. In the aberration diagram, Y is the object height.

According to the present embodiment, the catadioptric optics that corrects various aberrations well over a wide wavelength range (visible range) and a wide visual field range (imaging range) and is resistant to displacement of the image sensor in the optical axis direction. A system can be obtained.
[Example 2]
The catadioptric optical system 104B of Example 2 in FIG. 4 will be described. The parts not specifically mentioned are the same as those in the first embodiment. In the catadioptric optical system 104B of Example 2, the numerical aperture on the object side is 0.7, the magnification is 9.46 times, the object height is 7.2 mm, and the viewing area is φ14.4 mm. The visual field region satisfies φ3 mm or more and also satisfies φ10 mm or more.

  The angle formed by the optical axis of the principal ray at the principal wavelength (587.6 nm) is 0.6 degrees or less on the object plane and 0.03 degrees or less on the image plane. Further, the wavefront aberration in white light covering the visible wavelength range of 486 nm to 656 nm is suppressed to 50 mλrms or less.

  FIG. 5 shows lateral aberrations on the image surface (imaging device surface) of Example 2, and aberrations are well corrected in a wide wavelength band in the visible range both on and off the axis.

As described above, according to each embodiment, various aberrations are reduced over a wide wavelength region (visible region) and a wide visual field region (imaging region), and reflection is also strong against displacement of the image sensor in the optical axis direction. A refractive optical system and an imaging apparatus using the same can be obtained. The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

Hereinafter, numerical examples of the respective examples will be shown. The surface number is an optical surface in the order in which light counted from the object surface (sample surface) to the image surface passes. r is the radius of curvature of the i-th optical surface. d is the i-th and (i + 1) -th interval (the sign is positive when measured from the object side to the image plane side (when light travels) and negative in the reverse direction). Nd and νd indicate the refractive index and Abbe number of the material for a wavelength of 587.6 nm, respectively. The shape of the aspheric surface is represented by a general aspherical expression shown in the following expression. In the following equation, Z is a coordinate in the optical axis direction, c is a curvature (the reciprocal of the radius of curvature r), h is a height from the optical axis, and k is a cone coefficient. A, B, C, D, E, F, G, H, J... Are 4th, 6th, 8th, 10th, 12th, 14th, 16th, 18th, 20th, respectively. The following are aspherical coefficients.

“ ^EX ” means “10 ^−X ”.
[Numerical Example 1]

Surface number r d Nd νd
Object plane ∞ 6.47
1 751.86 12.05 1.5163 64.1
2 -1126.91 76.87
3 -89.99 6.84 1.5163 64.1
4 -122.34 -6.84 1.5163 64.1 Reflecting surface
5 -89.99 -66.87
6 ∞ -10.00 Aperture stop
7 -1126.91 -12.05 1.5163 64.1
8 751.86 12.05 1.5163 64.1 Reflecting surface
9 -1126.91 76.87
10 -89.99 6.84 1.5163 64.1
11 -122.34 4.00
12 301.27 10.37 1.8040 46.6
13 -27.60 6.51 1.7174 29.5
14 -3489.31 0.51
15 95.08 7.58 1.5163 64.1
16 -92.56 0.50
17 125.41 7.00 1.4875 70.2
18 -249.24 5.41
19 45.90 13.36 1.7174 29.5
20 -110.11 24.96
21 -36.17 5.00 1.7380 32.3
22 -388.60 1.12
23 119.71 28.72 1.4875 70.2
24 -55.20 0.50
25 55.01 18.01 1.7170 47.9
26 -575.37 0.50
27 82.67 10.14 1.8044 39.6
28 106.75 1.79
29 42.65 8.06 1.7495 35.3
30 49.57 15.78
31 -43.98 5.00 1.8000 29.8
32 169.41 19.16
33 -36.98 5.00 1.5481 45.8
34 -1547.75 24.85
35 -184.01 29.79 1.8052 25.4
36 -98.54 0.50
37 343.81 20.62 1.8052 25.4
38 -161.90 18.44
Image plane

(Aspheric coefficient)
Face number
1, 8 k = 0.00E + 00 A = 1.44E-08 B = -1.28E-12 C = 7.34E-16 D = -2.07E-19
E = 5.12E-23 F = -7.25E-27 G = 4.64E-31 H = 0.00E + 00 J = 0.00E + 00
4, 11 k = 0.00E + 00 A = 1.21E-08 B = 9.97E-13 C = 5.89E-17 D = 8.62E-21
E = -6.17E-25 F = 1.04E-28 G = -4.33E-34 H = 0.00E + 00 J = 0.00E + 00
12 k = 0.00E + 00 A = -7.58E-06 B = -3.65E-09 C = 1.22E-11 D = 1.73E-14
E = -1.79E-23 F = -2.04E-27 G = -4.53E-29 H = 0.00E + 00 J = 0.00E + 00
15 k = 0.00E + 00 A = 3.43E-06 B = -4.55E-10 C = -1.33E-12 D = -2.76E-15
E = -1.91E-23 F = -2.14E-27 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
18 k = 0.00E + 00 A = 1.96E-06 B = 2.53E-09 C = -4.54E-13 D = -2.65E-15
E = -7.93E-18 F = -2.04E-27 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
20 k = 0.00E + 00 A = 1.10E-06 B = 1.66E-09 C = 3.13E-12 D = -4.12E-15
E = 7.14E-18 F = 0.00E + 00 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
22 k = 0.00E + 00 A = -3.80E-06 B = 1.54E-09 C = -2.87E-13 D = -2.64E-15
E = 3.74E-18 F = 5.36E-23 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
26 k = 0.00E + 00 A = 1.07E-06 B = -7.88E-10 C = 7.49E-13 D = -3.03E-16
E = 4.21E-20 F = 8.60E-24 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
28 k = 0.00E + 00 A = 8.57E-07 B = 1.40E-09 C = -1.10E-12 D = 4.08E-16
E = -2.62E-19 F = -3.09E-22 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
32 k = 0.00E + 00 A = 7.31E-06 B = -4.03E-09 C = -1.31E-12 D = 5.42E-15
E = -9.28E-19 F = -2.27E-21 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
34 k = 0.00E + 00 A = -4.98E-06 B = 3.12E-09 C = -2.81E-12 D = 1.54E-15
E = -5.36E-19 F = 0.00E + 00 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
38 k = 0.00E + 00 A = 1.71E-07 B = -5.85E-13 C = -7.84E-15 D = 4.72E-18
E = -1.41E-21 F = 2.21E-25 G = -1.44E-29 H = 0.00E + 00 J = 0.00E + 00

[Numerical Example 2]

Surface number r d Nd νd
Object plane ∞ 6.36
1 742.92 11.76 1.5163 64.1
2 -1089.93 76.75
3 -90.05 6.87 1.5163 64.1
4 -122.52 -6.87 1.5163 64.1 Reflecting surface
5 -90.05 -66.75
6 ∞ -10.00 Aperture stop
7 -1089.93 -11.76 1.5163 64.1
8 742.92 11.76 1.5163 64.1 Reflecting surface
9 -1089.93 76.75
10 -90.05 6.87 1.5163 64.1
11 -122.52 3.83
12 381.53 8.96 1.7995 42.2
13 -27.22 5.45 1.7283 28.5
14 -258.64 2.39
15 244.10 7.17 1.5163 64.1
16 -72.51 0.50
17 61.22 6.23 1.4875 70.2
18 214.51 5.01
19 63.54 11.48 1.7495 35.3
20 -65.43 25.69
21 -36.84 5.01 1.7380 32.3
22 -379.12 1.57
23 142.83 25.18 1.4875 70.2
24 -53.47 3.15
25 54.13 19.47 1.6970 48.5
26 -505.98 0.50
27 82.07 10.46 1.8044 39.6
28 88.75 4.72
29 39.63 8.96 1.7234 38.0
30 50.12 16.01
31 -42.23 5.08 1.8340 37.2
32 208.10 18.08
33 -36.54 5.23 1.4875 70.2
34 2929.60 24.99
35 -197.90 30.00 1.7859 44.2
36 -90.83 18.44
37 380.08 30.00 1.7995 42.2
38 -214.76 4.50
Image plane

(Aspheric coefficient)
Face number
1, 8 k = 0.00E + 00 A = 1.34E-08 B = -1.29E-12 C = 7.44E-16 D = -2.07E-19
E = 5.01E-23 F = -7.10E-27 G = 4.62E-31 H = 0.00E + 00 J = 0.00E + 00
4, 11 k = 0.00E + 00 A = 1.21E-08 B = 9.69E-13 C = 5.95E-17 D = 7.33E-21
E = -2.96E-25 F = 6.16E-29 G = 1.56E-33 H = 0.00E + 00 J = 0.00E + 00
12 k = 0.00E + 00 A = -7.34E-06 B = -8.06E-09 C = 6.24E-11 D = -1.10E-13
E = -1.79E-23 F = -2.04E-27 G = -4.53E-29 H = 0.00E + 00 J = 0.00E + 00
15 k = 0.00E + 00 A = 4.96E-06 B = -6.12E-09 C = -2.06E-12 D = -6.61E-15
E = -1.91E-23 F = -2.14E-27 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
18 k = 0.00E + 00 A = 6.51E-06 B = 1.60E-09 C = 7.35E-14 D = -1.57E-14
E = -7.93E-18 F = -2.04E-27 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
20 k = 0.00E + 00 A = -8.63E-07 B = 1.52E-09 C = 2.49E-12 D = -2.08E-15
E = 7.14E-18 F = 0.00E + 00 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
22 k = 0.00E + 00 A = -4.08E-06 B = 1.82E-09 C = -6.40E-13 D = -2.42E-15
E = 3.74E-18 F = 5.36E-23 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
26 k = 0.00E + 00 A = 1.31E-06 B = -7.15E-10 C = 6.57E-13 D = -3.31E-16
E = 8.97E-20 F = -8.55E-24 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
28 k = 0.00E + 00 A = 9.11E-07 B = 1.22E-09 C = -8.29E-13 D = 2.68E-16
E = -6.07E-20 F = -3.09E-22 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
32 k = 0.00E + 00 A = 7.18E-06 B = -2.79E-09 C = -3.33E-12 D = 5.81E-15
E = -9.73E-19 F = -2.27E-21 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
34 k = 0.00E + 00 A = -4.88E-06 B = 2.91E-09 C = -2.44E-12 D = 1.27E-15
E = -4.25E-19 F = 0.00E + 00 G = 0.00E + 00 H = 0.00E + 00 J = 0.00E + 00
38 k = 0.00E + 00 A = 1.43E-07 B = -3.55E-11 C = 6.45E-16 D = 6.26E-18
E = -2.42E-21 F = 3.70E-25 G = -2.08E-29 H = 0.00E + 00 J = 0.00E + 00

  The present invention can be suitably used for a catadioptric optical system mounted on an imaging apparatus that images an enlarged sample.

104 Catadioptric optical system AS Aperture stop M1, M2 Mangin mirror

Claims (13)

From the object side to the image side,
A first light transmitting portion that transmits light from an object in a first region including the optical axis; and a second light that reflects the light on a surface of the second region that is further away from the optical axis than the first region. A first optical element having one light reflecting portion;
An aperture stop,
A second light transmitting portion that transmits the light in a third region including the optical axis, and a second light that reflects the light on the image-side surface of a fourth region farther from the optical axis than the third region. A second optical element having a reflection part,
The catadioptric optical system, wherein the aperture stop is disposed at a position where an angle formed between a principal ray having a principal wavelength of light incident on an image plane and the optical axis is 0.5 degrees or less.   When the absolute value of the lateral magnification of the catadioptric optical system is β, the aperture stop is at a position where the angle formed between the principal ray of the principal wavelength of the light emitted from the object and the optical axis is β degrees or less. The catadioptric optical system according to claim 1, wherein the catadioptric optical system is disposed. The catadioptric optical system is
A first imaging optical system having the first optical element, the aperture stop, and the second optical element, and condensing light from the object to form an intermediate image of the object;
The catadioptric optical system according to claim 1, further comprising: a second imaging optical system that forms the intermediate image on the image plane.   4. The catadioptric optical system according to claim 3, wherein a field lens is disposed at a position where the intermediate image is formed.   5. The catadioptric optical system according to claim 3, wherein a plane-parallel plate is disposed closer to the image side than the second imaging optical system.   6. The catadioptric optical system according to claim 1, wherein the dominant wavelength is in a visible light wavelength range.   The light from the object passes through the first light transmission portion, passes through the aperture stop, is reflected by the second light reflection portion, and the light reflected by the second light reflection portion is the aperture stop. The light reflected by the first light reflecting portion after passing through the first light reflecting portion passes through the aperture stop and passes through the second light transmitting portion. The catadioptric optical system according to any one of 1 to 6.   The catadioptric optical system according to claim 1, wherein the aperture stop is a variable stop.   The catadioptric optical system according to any one of claims 1 to 8, wherein the first light reflecting portion and the second light reflecting portion have a concave shape and an aspherical shape. . A light source;
An illumination optical system for illuminating an object with light from the light source;
The catadioptric optical system according to any one of claims 1 to 9, wherein light from the object is incident;
An image pickup apparatus comprising: an image pickup device that photoelectrically converts light emitted from the catadioptric optical system.   The imaging apparatus according to claim 10, further comprising an image processing system that generates image data from data acquired by the imaging element.   The imaging apparatus according to claim 10, wherein the light source emits visible light.   The imaging device according to claim 10, wherein a visual field region of the object is φ3 mm or more.