Macro Observation Device

Abstract

To provide a macro observation device combining telecentricity and compactness of the device at a high level.SOLUTION: A macro observation device comprises an image pick-up device and a macro optical system 30 for projecting a sample at a reduction rate of β. The macro optical system 30 comprises, in order from an object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, the second lens group G2 having the maximum light beam height less than half of the maximum light beam height of the first lens group G1; an aperture diaphragm AS; and a third lens group G3 having positive refractive power. The macro observation device meets the conditional expressions below, where d is the overal length of the macro optical system 30, L is a diameter of the visual field of the macro optical system 30, and α is an incident angle of the most off-axis principal ray of the macro optical system 30 on the object plane. 1.0<d / L<4.0 (1), |tan(α)|<0.23 (2)SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The disclosure of this specification relates to a macro observation device.

Background Art

[0002] In the field of life science research, digitalization of microscopes is required to reduce the opportunities for complex microscope operations and the burden on users. One of the typical tasks that impose a burden on users is sample searching. Macro observation is known as an effective means for sample searching. [[ID=*13]] [[ID=*14]]

[0003] [[ID=*15]] By providing a digital microscope capable of macro observation, it is possible to efficiently search for samples, and it is expected that the burden on users can be reduced. Patent Document 1 describes a microplate imaging system configured in a compact manner.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] <* By the way, the optical system of a microscope is generally configured as a telecentric optical system. However, in macro observation for a wide field of view, since telecentricity and lens diameter generally have a trade-off relationship, it is difficult to ensure high telecentricity with a compact device while securing a wide field of view.

[0006] Note: There are some tags marked with * that seem to be incomplete or incorrect in the original. This translation is based on the provided text as accurately as possible.In macro observation devices, prioritizing compactness at the expense of telecentricity can lead to problems such as the walls of the sample container appearing in the image during sample retrieval. This is undesirable considering that macro observation is used as a means to reduce the user's workload.

[0007] Based on the circumstances described above, one aspect of the present invention is to provide a macro observation device that achieves a high level of both telecentricity and compactness. [Means for solving the problem]

[0008] A macro observation device according to one aspect of the present invention comprises an image sensor and a macro optical system for projecting a sample onto the image sensor at a reduced magnification. The macro optical system consists of, in order from the object side, a first lens group having positive refractive power, a second lens group having negative refractive power, wherein the maximum ray height in the first lens group is less than or equal to half the maximum ray height in the first lens group, an aperture diaphragm, and a third lens group having positive refractive power. The macro observation device satisfies the following condition: where d is the total length of the macro optical system, L is the diameter of the field of view of the macro optical system, and α is the incident angle of the outermost principal ray of the macro optical system on the object plane. 1.0 <d / L<4.0 (1) |tan(α)|<0.23 (2) [Effects of the Invention]

[0009] According to the above embodiment, it is possible to provide a macro observation device that achieves a high level of both telecentricity and compactness. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram illustrates the configuration of a macro observation device 1 according to one embodiment. [Figure 2] This is a diagram illustrating the configuration of the macro optical system 30. [Figure 3]This diagram illustrates the conditions that the macro optical system 30 must satisfy. [Figure 4] This is a cross-sectional view of the macro optical system 31 according to Example 1. [Figure 5] Figure 4 shows the aberration diagram of the macro optical system 31. [Figure 6] This is a cross-sectional view of the macro optical system 32 according to Example 2. [Figure 7] Figure 6 shows the aberration diagram of the macro optical system 32. [Figure 8] This is a cross-sectional view of the macro optical system 33 according to Example 3. [Figure 9] Figure 8 shows the aberration diagram of the macro optical system 33. [Figure 10] This is a cross-sectional view of the macro optical system 34 according to Example 4. [Figure 11] Figure 10 shows the aberration diagram of the macro optical system 34. [Figure 12] This is a cross-sectional view of the macro optical system 35 according to Example 5. [Figure 13] Figure 12 shows the aberration diagram of the macro optical system 35. [Modes for carrying out the invention]

[0011] Figure 1 is a diagram illustrating the configuration of a macro observation device 1 according to one embodiment. The macro observation device 1 comprises an optical device 10 and a control device 100 that controls the optical device 10. The macro observation device 1 is, for example, a microscope device. The optical device 10 is, for example, an optical microscope, and the control device 100 is, for example, a microscope control device that controls the optical microscope.

[0012] In Figure 1, the optical device 10 is an inverted microscope, but the optical device 10 is not limited to an inverted microscope; it may also be an upright microscope. Furthermore, the optical device 10 may be an optical microscope that supports any microscopy method, such as one or more of the following: fluorescence microscopy, bright-field microscopy, dark-field microscopy, differential interference contrast microscopy, and phase contrast microscopy.

[0013] The control device 100 is a computer including at least a processor and a memory, and may control the optical device 10 by executing a control program. Further, the control device 100 may include a display device, and may display the digital image acquired by the optical device 10 on the display device. The display device is not particularly limited, and examples thereof include a liquid crystal display, an organic electroluminescence display, and the like.

[0014] As shown in FIG. 1, the optical device 10 includes a stage 20, a macro optical system 30, a micro optical system 40, and an imaging device 50. The optical device 10 may include other configurations not shown.

[0015] A container for accommodating a sample is disposed on the stage 20. The stage 20 is, for example, a motorized stage and is movable at least back and forth on the optical axis of the macro optical system 30 and on the optical axis of the micro optical system 40. The stage 20 may move by driving a stepping motor connected to a ball screw. Note that the actuator of the stage 20 is not limited to the combination of a ball screw and a stepping motor. For example, an ultrasonic motor or the like may be used instead of the stepping motor. Further, the actuator may be provided with an encoder for detecting the amount of movement. Also, the stage 20 may be a manual stage instead of a motorized stage.

[0016] The container for the sample disposed on the stage 20 is, for example, a multi-well plate 21 having a plurality of wells 22 as shown in FIG. 1. However, the container is not limited to the multi-well plate 21, and any container such as a dish or a flask may be adopted. Further, the sample may be placed on a slide glass, or may be sandwiched between a slide glass and a cover glass to form a preparation. In this case, the slide glass and the cover glass can be regarded as a container for the sample.

[0017] The macro optical system 30 projects the sample onto the image sensor 50 at a reduced magnification. The macro optical system 30 has a magnification of less than 1x, preferably 0.1x or less. On the other hand, the micro optical system 40 has a magnification of 1x or more. The micro optical system 40 projects the sample onto the image sensor 50 at 1x or magnified magnification. In Figure 1, an example is shown in which the image sensor 50 is shared for macro observation using the macro optical system 30 and micro observation using the micro optical system 40, but the image sensor 50 may be provided separately for macro observation and micro observation.

[0018] The image sensor 50 converts incident light into an electrical signal. The image sensor 50 is, for example, a two-dimensional image sensor, and may be a CCD (Charge Coupled Device), CMOS (Complementary Metal Oxide Semiconductor), etc. The optical device 10 outputs a digital image based on the signal output from the image sensor 50 to the control device 100.

[0019] In the macro observation device 1 configured as described above, the observation position can be determined by macro observation using the macro optical system 30, and then the sample can be observed in detail by micro observation using the micro optical system 40. Therefore, the user can observe the sample with high work efficiency.

[0020] Furthermore, the macro observation device 1 features a compact macro optical system 30 with high telecentricity. Therefore, the macro observation device 1 achieves a high level of both telecentricity and compactness.

[0021] Figure 2 illustrates the configuration of the macro optical system 30. Figure 3 illustrates the conditions that the macro optical system 30 must satisfy. Below, the macro optical system 30 will be described in more detail with reference to Figures 2 and 3.

[0022] As shown in Figure 2, the macro optical system 30 has a positive-negative-positive three-group configuration. The macro optical system 30 consists of a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, an aperture diaphragm AS, and a third lens group G3 with positive refractive power, arranged in this order from the object side. The maximum ray height in the second lens group G2 is less than half of the maximum ray height in the first lens group G1. The boundary between the first lens group G1 and the second lens group G2 can be identified by this characteristic.

[0023] The first lens group G1 may consist of one lens or two or more lenses. An aspherical lens may be used in the first lens group G1. Using an aspherical lens can suppress aberrations and improve telecentricity. Alternatively, a Fresnel lens may be used in the first lens group G1. Using a Fresnel lens allows for thinner individual lenses.

[0024] The first lens group G1 is preferably composed of at least two lenses. Furthermore, it is preferable that at least one of the at least two lenses included in the first lens group G1 has a strong positive refractive power on the object side. More specifically, this at least one lens includes an image-side surface and a convex object-side surface, and it is preferable that the object-side surface has a greater refractive power than the image-side surface. The image-side surface is, for example, a plane, but it may be convex or concave. This configuration is effective in correcting pupil aberration well and configuring the macro optical system 30 as an object-side telecentric optical system. Here, an object-side telecentric optical system refers to an optical system that satisfies condition (2) described later.

[0025] The second lens group G2 is preferably composed of at least two lenses. Furthermore, it is preferable that at least one of the at least two lenses included in the second lens group G2 has a strong negative refractive power on the image plane side. More specifically, this at least one lens includes an object-side surface and a concave image-side surface, and it is preferable that the image-side surface has a greater refractive power than the object-side surface. The object-side surface is, for example, a plane, but may be convex or concave. This configuration is effective in correcting pupil aberration well and configuring the macro optical system 30 as an object-side telecentric optical system.

[0026] The third lens group G3 preferably consists of at least two lenses, including a lens with positive refractive power (positive lens) and a lens with negative refractive power (negative lens).

[0027] Macro observation device 1 satisfies the following conditions (1) and (2). 1.0 <d / L<4.0 (1) |tan(α)|<0.23 (2)

[0028] However, d is the total length of the macro optical system 30. L is the diameter of the field of view of the macro optical system 30. α is the angle between the outermost principal ray of the macro optical system 30 on the object plane and the optical axis of the macro optical system 30. The total length of the macro optical system 30 refers to the distance along the optical axis from the object plane to the image plane when the lenses constituting the macro optical system are arranged in a single line. The outermost principal ray is the ray that passes through the center of the aperture diaphragm AS among the rays that pass through the edge of the field of view of the macro optical system 30.

[0029] Condition (1) specifies the conditions for constructing a compact macro optical system. When d / L is 4.0 or greater, the overall length of the macro optical system becomes too long relative to the field of view. This results in the device becoming too long in the optical axis direction, or the device configuration becoming complicated due to folding in the optical path. On the other hand, when d / L is 1.0 or less, L becomes small, making it difficult to secure the field of view necessary for macro observation. By satisfying condition (1), a compact macro optical system can be constructed.

[0030] Condition (2) defines the telecentricity of the macro optical system. When |tan(α)| is greater than 0.23, the angle of the principal ray becomes too sharp. As a result, the container wall is largely reflected in the field of view. In particular, with multi-well plates with relatively small well diameters, the proportion of the wall reflected relative to the well size becomes too large, hindering the observation of the sample. By satisfying condition (2), the proportion of the container wall reflected in the field of view can be reduced. More specifically, even when using a 96-well multi-well plate (for example, as shown in Figure 3, with a well diameter t of 5.17 mm and a wall height h of 11.4 mm), the proportion of the wall reflected in the well image can be reduced to less than half.

[0031] By satisfying the above-mentioned conditions (1) and (2), the macro observation device 1 can achieve a high level of both telecentricity and compactness.

[0032] Furthermore, the macro observation device 1 may satisfy condition (1-1) instead of condition (1). This makes it possible to achieve an even higher level of balance between telecentricity and the compactness of the device. 1.5 <d / L<2.5 (1-1)

[0033] The macro observation device 1 may also satisfy at least one of the following conditions (3) to (5). 0.4 < (d12 + d2s) / f1 < 1.0 (3) 0.35 < (d12 + d2s) / d < 0.65 (4) 0.6 < |f23 / (f1×β)| < 1.2 (5)

[0034] However, f1 is the focal length of the first lens group G1. f23 is the combined focal length of the second lens group G2 and the third lens group G3. β is the magnification of the macro optical system 30. d12 is the distance along the optical axis from the image-side lens surface of the first lens group G1 to the object-side lens surface of the second lens group G2. d2s is the distance along the optical axis from the image-side lens surface of the second lens group G2 to the aperture diaphragm AS.

[0035] Condition (3) defines the relationship between the distances between the components of the macro optical system 30 and the focal length of the first lens group G1. In the paraxial region, a perfectly object-side telecentric optical system satisfies (d12+d2s) / f1=1.0. As (d12+d2s) / f1 decreases, the telecentricity deteriorates, and when it falls below 0.4, it becomes difficult to ensure sufficient telecentricity without sacrificing a wide field of view and compactness of the device. By satisfying condition (2), a good balance between a wide field of view, telecentricity, and compactness of the device can be achieved.

[0036] Condition (4) defines the relationship between the total length of the macro optical system 30 and the distances between its components. If (d12+d2s) / d is 0.35 or less, the components from the first lens group G1 to the aperture diaphragm AS must be made excessively compact, making it difficult to design lenses that ensure telecentricity. If (d12+d2s) / d is 0.65 or more, the components from the aperture diaphragm AS to the third lens group G3 must be made excessively compact, making lens design difficult. By satisfying condition (4), the components from the first lens group G1 to the third lens group G3 can be arranged with a relatively high degree of freedom, thus achieving a better balance between wide field of view, telecentricity, and compactness of the device.

[0037] Condition (5) defines the relationship between the magnification of the macro optical system 30, the focal length of the front group (first lens group G1), and the focal lengths of the rear group (second lens group G2, third lens group G3). In the paraxial region, a perfectly bilateral telecentric optical system satisfies |f23 / (f1×β)|=1.0. If |f23 / (f1×β)| is 0.6 or less or 1.2 or more, the telecentricity deteriorates on both the object and image sides, making it difficult to obtain high imaging performance. By satisfying condition (5), a better balance of wide field of view, telecentricity, and compactness of the device can be achieved.

[0038] Furthermore, the macro observation device 1 may satisfy conditions (3-1) to (5-1) instead of conditions (3) to (5). This allows for a better balance between wide field of view, telecentricity, and compactness of the device. 0.62 < (d12 + d2s) / f1 < 0.79 (3-1) 0.38 < (d12 + d2s) / d < 0.5 (4-1) 0.75<|f23 / (f1×β)|<0.95 (5-1)

[0039] The macro observation device 1 may satisfy the following condition (6) if the third lens group G3 consists of at least two lenses, including a positive lens and a negative lens. 15 < ν3p - ν3n < 50 (6)

[0040] However, ν3p is the Abbe number of any positive lens included in the third lens group G3, and ν3n is the Abbe number of any negative lens included in the third lens group G3.

[0041] Conditional equation (6) specifies a desirable range for the difference in Abbe numbers between the positive and negative lenses included in the third lens group G3. By satisfying conditional equation (6) for the lenses, axial chromatic aberration and lateral chromatic aberration can be effectively corrected through the achromatic effect of the combination of a low-dispersion (high Abbe number) positive lens and a high-dispersion (low Abbe number) negative lens.

[0042] Note that the macro observation device 1 may also satisfy condition (6-1) instead of condition (6). This allows for even better correction of chromatic aberration. 24.26 < ν3p - ν3n < 46.45 (6-1)

[0043] The macro observation device 1 may also satisfy both of the following conditions (7) and (8). |Dt×I| <ls / (2×βs) (7) -1.3<(d12+d2s) / f1+d2s / f2+d3s / f3<0.2 (8)

[0044] However, Dt is the optical distortion of the macro optical system 30. Optical distortion is expressed as the difference between the ideal image height Y and the actual image height y divided by the ideal image height (Yy / Y). I is the maximum object height within the shooting range of the macro optical system 30. βs is the magnification of the micro optical system 40. ls is the diagonal length of the imaging plane of the image sensor 50. f2 is the focal length of the second lens group G2. f3 is the focal length of the third lens group G3. d3s is the distance on the optical axis from the aperture diaphragm AS to the lens surface of the third lens group G3 closest to the object.

[0045] Condition (7) defines the acceptable magnitude of distortion in the macro optical system 30. By satisfying condition (7), the magnitude of distortion occurring in the macro optical system 30 becomes smaller than the field of view of the micro optical system. Therefore, when switching from the macro optical system 30 to the micro optical system 40, it is possible to avoid the designated point of interest using the macro optical system 30 moving outside the field of view of the micro optical system 40.

[0046] Condition (8) defines the balance of power generated in the lens groups before and after the aperture diaphragm AS. By satisfying condition (8), the amount of distortion can be suppressed from the low image height region to the high image height region.

[0047] Note that the macro observation device 1 may satisfy condition (8-1) instead of condition (8). This will further suppress distortion. -1.02<(d12+d2s) / f1+d2s / f2+d3s / f3<0.10 (8-1)

[0048] When the macro observation device 1 is used to observe a sample placed in a well, it may satisfy the following condition (9). |h × tan(α)| <t / 2 (9)

[0049] However, h is the height of the wall of the well 22 that contains the sample, and t is the diameter of the well 22.

[0050] Condition (9) defines the telecentricity of the macro optical system in relation to the sample container. By satisfying condition (9), it is possible to avoid the wall of well 22 appearing in more than half of the field of view.

[0051] The following describes in detail an embodiment of the macro optical system 30 mentioned above. [Example 1] Figure 4 is a cross-sectional view of the macro optical system 31 according to this embodiment. The macro optical system 31 consists of, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture diaphragm AS, and a third lens group G3 having positive refractive power. The macro optical system 31 is an optical system that projects the image of the object surface (surface number s1) onto the image plane (surface number s10).

[0052] The first lens group G1 consists of lens L1, which is a plano-convex lens with a convex surface facing the object. The second lens group G2 consists of lens L2, which is a plano-concave lens with a flat surface facing the object. The third lens group G3 consists of a cemented lens CL1, which is composed of lens L3, a biconvex lens, and lens L4, a meniscus lens with a concave surface facing the object, arranged in order from the object side.

[0053] The various data for the macro optical system 31 are as follows: f1=161mm, f2=-15.7mm, f3=16.4mm, d12=87.31mm, d23=24.862mm, d2s=2.862mm, d3s=2mm, f23=9.51mm, Dt=0.69%, d=219.57mm, L=119.3901998mm, β=0.074713, Maximum ray height of lens group G1=51.70457mm, Maximum ray height of lens group G2=5.99998mm, Aperture NA=0.0041

[0054] The lens data for macro optical system 31 is as follows. Note that INF in the lens data indicates infinity (∞). Macro Optical System 31 srdn vd 1 INF 45.0000 2 83.4862 27.0000 1.51633 64.14 3 INF 87.3064 4 INF 3.5000 1.48749 70.23 5 7.6640 22.8620 6 INF 2.0000 7 19.5000 4.0000 1.56883 56.36 8 -4.7288 2.5000 1.67270 32.10 9 -11.7818 25.3984 10 INF

[0055] Here, s represents the surface number, r represents the radius of curvature (mm), d represents the interplanar spacing (mm), nd represents the refractive index with respect to line d, and νd represents the Abbe number. These symbols are the same in subsequent examples. The surfaces indicated by surface numbers s1, s6, and s10 are the object surface, the aperture diaphragm AS surface, and the image surface, respectively.

[0056] The macro optical system 31 satisfies conditions (1) through (9) as shown below. Conditions (7) and (9) were calculated under the conditions I=59.69509mm, ls=8.92mm, βs=4, h=11.4mm, and t=5.17mm. (1) d / L = 1.839095674 (2) tan(α) = -0.08745 (3) (d12+d2s) / f1=0.684298137 (4) (d12+d2s) / d=0.500781818 (5) |f23 / (f1×β)|=0.790603014 (6) ν3p-ν3n=24.26 (7) Left side |Dt × I| = 0.232213 mm (7) Right side: ls / (2×βs) = 1.115 mm (8) (d12+d2s) / f1+d2s / f2+d3s / f3=-0.893831427 (9) Left side |h × tan(α)| = 0.9804 mm (9) Right side t / 2=2.585mm

[0057] Figure 5 is an aberration diagram of the macro optical system 31 shown in Figure 4, illustrating aberrations at the image plane. Figure 5(a) is a spherical aberration diagram. Figure 5(b) is an astigmatism diagram. Figure 5(c) is a distortion aberration diagram. Figure 5(d) is a chromatic aberration diagram. Figures 5(e) and 5(f) are coma aberration diagrams at an image height of 3.13 mm and 4.48 mm, respectively. In the figures, "M" represents the meridional component and "S" represents the sagittal component. Similar aberration diagrams are shown in subsequent embodiments. Figure 5 demonstrates that the various aberrations have been well corrected.

[0058] [Example 2] Figure 6 is a cross-sectional view of the macro optical system 32 according to this embodiment. The macro optical system 32 consists of, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture diaphragm AS, and a third lens group G3 having positive refractive power. The macro optical system 32 is an optical system that projects the image of the object surface (surface number s1) onto the image plane (surface number s16).

[0059] The first lens group G1 includes lenses L1 and L2, arranged in order from the object side. Lens L1 is a plano-convex lens with a convex surface facing the object. Lens L2 is a plano-convex lens with a convex surface facing the object. The second lens group G2 includes lenses L3 and L4, arranged in order from the object side. Lens L3 is a meniscus lens with a concave surface facing the image side. Lens L4 is a meniscus lens with a concave surface facing the image side. The third lens group G3 includes lenses L5 and a cemented lens CL1, arranged in order from the object side. Lens L5 is a plano-convex lens with a flat surface facing the object side. The cemented lens CL1 consists of a biconvex lens L6 and a meniscus lens L7 with a concave surface facing the object side, arranged in order from the object side.

[0060] The various data for the macro optical system 32 are as follows: f1=154mm, f2=-12.5mm, f3=14.54mm, d12=88.62mm, d23=17.89mm, d2s=13.89mm, d3s=4mm, f23=9.45mm, Dt=-2.69%, d=219.63mm, L=119.0698668mm, β=0.074914, Maximum ray height of lens group G1=52.46471mm, Maximum ray height of lens group G2=6.77301mm, Aperture NA=0.0044

[0061] The lens data for the macro optical system 32 is as follows. Note that INF in the lens data indicates infinity (∞). Also, the planes indicated by plane numbers s1, s10, and s16 are the object plane, the aperture diaphragm AS plane, and the image plane, respectively. Macro Optical System 32 srdn vd 1 INF 45.0000 2 157.0946 13.0000 1.51633 64.14 3 INF 0.0 4 157.0946 13.0000 1.51633 64.14 5 INF 88.6232 6 15.0000 3.5000 1.48749 70.23 7 7.1993 2.0000 8 26.1050 3.5000 1.48749 70.23 9 7.1993 13.8888 10 INF 4.0000 11 INF 4.5000 1.51633 64.14 12 -10.8040 0.2000 13 18.6950 4.0000 1.48749 70.23 14 -10.9230 2.5000 1.72825 28.46 15 -41.1550 21.9100 16 INF

[0062] The macro optical system 32 satisfies conditions (1) through (9), with the exception of condition (7), as shown below. Conditions (7) and (9) were calculated under the conditions I=59.53493mm, ls=8.92mm, βs=4, h=11.4mm, and t=5.17mm. (1) d / L = 1.844547289 (2) tan(α) = -0.08894 (3) (d12+d2s) / f1=0.665649351 (4) (d12+d2s) / d=0.465954545 (5) |f23 / (f1×β)|=0.819121077 (6) ν3p-ν3n=41.77 (7) Left side |Dt × I| = 1.488373 mm (7) Right side: ls / (2×βs) = 1.115 mm (8) (d12+d2s) / f1+d2s / f2+d3s / f3=-0.720653813 (9) Left side |h × tan(α)| = 1.0032 mm (9) Right side t / 2=2.585mm

[0063] Figure 7 shows the aberration diagrams of the macro optical system 32 shown in Figure 6, illustrating aberrations at the image plane. Figure 7(a) is a spherical aberration diagram. Figure 7(b) is an astigmatism diagram. Figure 7(c) is a distortion aberration diagram. Figure 7(d) is a chromatic aberration diagram. Figures 7(e) and 7(f) are coma aberration diagrams at an image height of 3.13 mm and 4.48 mm, respectively. Figure 7 shows that the various aberrations are well corrected.

[0064] [Example 3] Figure 8 is a cross-sectional view of the macro optical system 33 according to this embodiment. The macro optical system 33 consists of, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture diaphragm AS, and a third lens group G3 having positive refractive power. The macro optical system 33 is an optical system that projects the image of the object surface (surface number s1) onto the image plane (surface number s17).

[0065] The first lens group G1 includes lenses L1 and L2, arranged in order from the object side. Lens L1 is a plano-convex lens with a convex surface facing the object. Lens L2 is a plano-convex lens with a convex surface facing the object. The second lens group G2 consists of lens L3, which is a plano-concave lens with a concave surface facing the image side. The third lens group G3 includes lens L4, cemented lens CL1, and cemented lens CL2, arranged in order from the object side. Lens L4 is a meniscus lens with a concave surface facing the object side. Cemented lens CL1 consists of lens L5, which is a plano-concave lens with a flat surface facing the object side, and lens L6, which is a biconvex lens, arranged in order from the object side. Cemented lens CL2 consists of lens L7, which is a biconvex lens, and lens L8, which is a plano-concave lens with a concave surface facing the object side, arranged in order from the object side.

[0066] The various data for the macro optical system 33 are as follows: f1=129mm, f2=-9mm, f3=12mm, d12=95.12mm, d23=9.8mm, d2s=6.34mm, d3s=3.47mm, f23=9.2mm, Dt=-1.27%, d=220.01mm, L=118.9333333mm, β=0.075, Maximum ray height of lens group G1=47.81166mm, Maximum ray height of lens group G2=1.96287mm, Aperture NA=0.0053

[0067] The lens data for macro optical system 33 is as follows. Note that INF in the lens data indicates infinity (∞). Also, the planes indicated by plane numbers s1, s8, and s17 are the object plane, the aperture diaphragm AS plane, and the image plane, respectively. Macro Optical System 33 srdn vd 1 INF 35.0000 2 128.9891 20.0000 1.51633 64.14 3 INF 1.0000 4 128.9891 20.0000 1.51633 64.14 5 INF 95.1214 6 INF 3.0000 1.48749 70.23 7 4.4276 6.3390 8 INF 3.4781 9 -76.1313 4.0064 1.57135 52.95 10 -9.5614 0.4000 11 INF 2.5000 1.67270 32.10 12 12.8867 4.5000 1.56883 56.36 13 -21.2939 0.4000 14 21.2939 4.5000 1.56883 56.36 15 -12.8867 2.5000 1.67270 32.10 16 INF 17.2648 17 INF

[0068] The macro optical system 33 satisfies conditions (1) through (9) as shown below. Conditions (7) and (9) were calculated under the conditions I=59.46666mm, ls=8.92mm, βs=4, h=11.4mm, and t=5.17mm. (1) d / L = 1.849859865 (2) tan(α) = 0.00873 (3) (d12+d2s) / f1=0.786511628 (4) (d12+d2s) / d=0.461181818 (5) |f23 / (f1×β)|=0.950904393 (6) ν3p-ν3n=24.26 (7) Left side |Dt × I| = 0.74928 mm (7) Right side: ls / (2×βs) = 1.115 mm (8) (d12+d2s) / f1+d2s / f2+d3s / f3=-0.207099483 (9) Left side |h × tan(α)| = 0.057 mm (9) Right side t / 2=2.585mm

[0069] Figure 9 shows the aberration diagrams of the macro optical system 33 shown in Figure 8, illustrating aberrations at the image plane. Figure 9(a) is a spherical aberration diagram. Figure 9(b) is an astigmatism diagram. Figure 9(c) is a distortion aberration diagram. Figure 9(d) is a chromatic aberration diagram. Figures 9(e) and 9(f) are coma aberration diagrams at an image height of 3.36 mm and 4.03 mm, respectively. Figure 9 shows that the various aberrations are well corrected.

[0070] [Example 4] Figure 10 is a cross-sectional view of the macro optical system 34 according to this embodiment. The macro optical system 34 consists of, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture diaphragm AS, and a third lens group G3 having positive refractive power. The macro optical system 34 is an optical system that projects the image of the object surface (surface number s1) onto the image plane (surface number s12).

[0071] The first lens group G1 consists of lens L1, which is a plano-convex lens with its convex surface facing the object. The second lens group G2 consists of lens L2, which is a plano-concave lens with its flat surface facing the object. The third lens group G3 consists of lens L3 and cemented lens CL1, arranged in order from the object side. Lens L3 is a meniscus lens with its concave surface facing the object. The cemented lens CL1 consists of lens L4, which is a biconvex lens, and lens L5, which is a meniscus lens with its concave surface facing the object, arranged in order from the object side.

[0072] The various data for the macro optical system 34 are as follows: f1=130mm, f2=-15mm, f3=14mm, d12=77.36mm, d23=18.7mm, d2s=12mm, d3s=6.74mm, f23=9.04mm, Dt=4.08%, d=179.8mm, L=104.2056075mm, β=0.0856, Maximum ray height of lens group G1=46.91435mm, Maximum ray height of lens group G2=3.0925mm, Aperture NA=0.0063

[0073] The lens data for the macro optical system 34 is as follows. Note that INF in the lens data indicates infinity (∞). Also, the planes indicated by plane numbers s1, s6, and s12 are the object plane, the aperture diaphragm AS plane, and the image plane, respectively. Macro Optics 34 srdn vd 1 INF 30.0000 2 67.3610 21.8000 1.51633 64.14 3 INF 77.3628 4 INF 2.0000 1.84666 23.78 5 12.7582 11.9990 6 INF 6.7384 7 -12.0245 2.5000 1.66672 48.32 8 -8.0393 0.4000 9 15.4211 5.0000 1.48749 70.23 10 -8.7816 2.0000 1.84666 23.78 11 -18.2080 20.0000 12 INF

[0074] The macro optical system 34 satisfies conditions (1) through (9) as shown below. Conditions (7) and (9) were calculated under the conditions I=52.10280mm, ls=8.92mm, βs=4, h=11.4mm, and t=5.17mm. (1) d / L = 1.725434978 (2) tan(α) = -0.04637 (3) (d12+d2s) / f1=0.687384615 (4) (d12+d2s) / d=0.406181818 (5) |f23 / (f1×β)|=0.812365205 (6) ν3p - ν3n = 46.45 (7) Left side |Dt × I| = 1.609976 mm (7) Right side: ls / (2×βs) = 1.115 mm (8) (d12+d2s) / f1+d2s / f2+d3s / f3=-0.594043956 (9) Left side |h × tan(α)| = 0.6156 mm (9) Right side t / 2=2.585mm

[0075] Figure 11 is an aberration diagram of the macro optical system 34 shown in Figure 10, illustrating aberrations at the image plane. Figure 11(a) is a spherical aberration diagram. Figure 11(b) is an astigmatism diagram. Figure 11(c) is a distortion aberration diagram. Figure 11(d) is a chromatic aberration diagram. Figures 11(e) and 11(f) are coma aberration diagrams at an image height of 3.60 mm and 4.50 mm, respectively. Figure 11 shows that the various aberrations are well corrected.

[0076] [Example 5] Figure 12 is a cross-sectional view of the macro optical system 35 according to this embodiment. The macro optical system 35 consists of, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture diaphragm AS, and a third lens group G3 having positive refractive power. The macro optical system 35 is an optical system that projects the image of the object surface (surface number s1) onto the image plane (surface number s12).

[0077] The first lens group G1 consists of lens L1, which is a plano-convex lens with its convex surface facing the object. The second lens group G2 consists of lens L2, which is a plano-concave lens with its flat surface facing the object. The third lens group G3 consists of lens L3 and cemented lens CL1, arranged in order from the object side. Lens L3 is a plano-convex lens with its flat surface facing the object. The cemented lens CL1 consists of lens L4, which is a biconvex lens, and lens L5, which is a meniscus lens with its concave surface facing the object, arranged in order from the object side.

[0078] The various data for the macro optical system 35 are as follows: f1=134mm, f2=-15.95mm, f3=11.5mm, d12=79.59mm, d23=6.72mm, d2s=2.72mm, d3s=4mm, f23=11.53mm, Dt=1.06%, d=180mm, L=83.74564607mm, β=0.106513, Maximum ray height of lens group G1=35.17873mm, Maximum ray height of lens group G2=2.81192mm, Aperture NA=0.0091

[0079] The lens data for the macro optical system 35 is as follows. Note that INF in the lens data indicates infinity (∞). Also, the planes indicated by plane numbers s1, s6, and s12 are the object plane, the aperture diaphragm AS plane, and the image plane, respectively. Macro Optics 35 srdn vd 1 INF 35.0000 2 69.3684 26.0000 1.51633 64.14 3 INF 79.5861 4 INF 3.5000 1.48749 70.23 5 7.7760 2.7154 6 INF 4.0000 7 INF 4.5000 1.51633 64.14 8 -8.1173 0.2000 9 49.7571 4.0000 1.48749 70.23 10 -6.2192 2.5000 1.72825 28.46 11 -12.0622 18.0000 12 INF

[0080] The macro optical system 35 satisfies conditions (1) through (9) as shown below. Conditions (7) and (9) were calculated under the conditions I=41.87282mm, ls=8.92mm, βs=4, h=11.4mm, and t=5.17mm. (1) d / L = 2.149365471 (2) tan(α) = -0.06887 (3) (d12+d2s) / f1=0.614253731 (4) (d12+d2s) / d=0.457277778 (5) |f23 / (f1×β)|=0.807833561 (6) ν3p-ν3n=41.77 (7) Left side |Dt × I| = 0.35968 mm (7) Right side: ls / (2×βs) = 1.115 mm (8) (d12+d2s) / f1+d2s / f2+d3s / f3=0.095894729 (9) Left side |h×tan(α)|=0.7866mm (9) Right side t / 2=2.585mm

[0081] Figure 13 is an aberration diagram of the macro optical system 35 shown in Figure 12, illustrating aberrations at the image plane. Figure 13(a) is a spherical aberration diagram. Figure 13(b) is an astigmatism diagram. Figure 13(c) is a distortion aberration diagram. Figure 13(d) is a chromatic aberration diagram. Figures 13(e) and 13(f) are coma aberration diagrams at an image height of 3.13 mm and 4.48 mm, respectively. Figure 13 shows that the various aberrations are well corrected. [Explanation of Symbols]

[0082] 1. Macro observation device 10 Optical equipment 20 stages 21-well plate 22 wells 30-35 Macro Optics 40 Microoptical Systems 50 Image sensors 100 Control device G1 First Lens Group G2 Second Lens Group G3 3rd lens group AS aperture diaphragm

Claims

1. An imaging element; a macro optical system that projects a sample onto the imaging element at a reduced magnification; The macro optical system includes, in order from the object side, a first lens group having positive refractive power; a second lens group having negative refractive power, wherein a maximum ray height in the second lens group is equal to or less than half of a maximum ray height in the first lens group; An aperture stop, a third lens group having a positive refractive power, The macro observation device satisfies the following conditional expression: A macro observation device characterized by: 1.0<d / L<4.0 (1) |tan(α)|<0.23 (2) where d is the total length of the macro optical system, L is the diameter of the field of view of the macro optical system, and α is the angle of incidence of the most off-axis chief ray of the macro optical system on the object plane.

2. 2. The macro observation device according to claim 1, The macro observation device satisfies the following conditional expression: A macro observation device characterized by: 0.4<(d12+d2s) / f1<1.0 (3) Here, f1 is the focal length of the first lens group, d12 is the distance on the optical axis from the lens surface of the first lens group closest to the image to the lens surface of the second lens group closest to the object, and d2s is the distance on the optical axis from the lens surface of the second lens group closest to the image to the aperture stop.

3. 3. The macro observation device according to claim 1, The macro observation device satisfies the following conditional expression: A macro observation device characterized by: 0.35<(d12+d2s) / d<0.65 (4) Here, d12 is the distance on the optical axis from the lens surface of the first lens group closest to the image to the lens surface of the second lens group closest to the object, and d2s is the distance on the optical axis from the lens surface of the second lens group closest to the image to the aperture stop.

4. The macro observation device according to any one of claims 1 to 3, The macro observation device satisfies the following conditional expression: A macro observation device characterized by: 0.6<|f23 / (f1×β)|<1.2 (5) Here, f1 is the focal length of the first lens group, f23 is the combined focal length of the second and third lens groups, and β is the magnification of the macro optical system.

5. 5. The macro observation device according to claim 1, The third lens group is a positive lens having a positive refractive power; a negative lens having a negative refractive power, The macro observation device satisfies the following conditional expression: A macro observation device characterized by: 15<ν3p−ν3n<50 (6) Here, v3p is the Abbe number of the positive lens, and v3n is the Abbe number of the negative lens.

6. 6. The macro observation device according to claim 1, the first lens group is made up of at least two lenses, At least one lens of the at least two lenses included in the first lens group is an image-side surface; an object-side surface that has a refractive power greater than that of the image-side surface and is a convex surface; A macro observation device characterized by:

7. 7. The macro observation device according to claim 1, the second lens group is made up of at least two lenses, At least one lens of the at least two lenses included in the second lens group is the object-side surface, an image-side surface that has a refractive power greater than that of the object-side surface and is a concave surface; A macro observation device characterized by:

8. The macro observation device according to any one of claims 1 to 7, further comprising: a micro-optical system having a magnification of 1x or more; the macro optical system has a magnification of 0.1 times or less, The macro observation device satisfies the following conditional expression: A macro observation device characterized by: |Dt×I|<ls / (2×βs) (7) -1.3<(d12+d2s) / f1+d2s / f2+d3s / f3<0.2 (8) Here, Dt is the optical distortion of the macro optical system. I is the maximum object height within the shooting range of the macro optical system. βs is the magnification of the micro optical system. ls is the diagonal length of the imaging surface of the image sensor. f1 is the focal length of the first lens group. f2 is the focal length of the second lens group. f3 is the focal length of the third lens group. d12 is the distance on the optical axis from the lens surface of the first lens group closest to the image to the lens surface of the second lens group closest to the object. d2s is the distance on the optical axis from the lens surface of the second lens group closest to the image to the aperture stop. d3s is the distance on the optical axis from the aperture stop to the lens surface of the third lens group closest to the object.

9. 9. The macro observation device according to claim 1, The macro observation device satisfies the following conditional expression: A macro observation device characterized by: |h×tan(α)|<t / 2 (9) where h is the wall height of the well containing the sample, and t is the diameter of the well.

Images