JP4939831B2 - Stereo microscope - Google Patents

Description

  The present invention relates to a stereomicroscope capable of observing a specimen three-dimensionally and having a wide workable range of magnification from low to high magnification and good workability.

  Conventionally, stereomicroscopes have been widely used in manufacturing and biological experiments. FIG. 12 is a diagram illustrating a general configuration of an optical system included in the single-objective binocular stereomicroscope. As shown in this figure, the stereomicroscope includes an objective lens 22, a zoom lens body 23, and a lens barrel 24 above the specimen SP ′ placed on the glass plate 21. The zoom lens body 23 has two zooming optical systems 23L and 23R capable of zooming zooming, and the lens barrel 24 displays a specimen image of the specimen SP ′ corresponding to each of the zooming optical systems 23L and 23R. It has imaging optical systems 24L and 24R for imaging. The imaging optical systems 24L and 24R are configured using imaging lenses 24La and 24Ra, prisms 24Lb and 24Rb, and eyepiece lenses 24Lc and 24Rc, respectively.

The variable magnification optical systems 23L and 23R receive light emitted from the specimen SP ′ in different directions via the objective lens 22, respectively. The imaging lenses 24La and 24Ra receive the light emitted from the variable magnification optical systems 23L and 23R, respectively, and form sample images. The prisms 24Lb and 24Rb respectively convert sample images as inverted images formed by the imaging lenses 24La and 24Ra into erect images. Each sample image converted into an erect image is observed through the eyepieces 24Lc and 24Rc.
JP 10-26729 JP 2004-54259 A

By the way, in recent years, cases of observing experimental animals such as mice, nematodes, zebrafish, medaka, and Drosophila are increasing. In these experimental animals, there are many cases where fluorescent proteins such as GFP are expressed and observed. In this case, both the low-magnification observation to check the whole laboratory animal and pick up the solid that fluoresces from many solids and the high-magnification observation to check the fluorescence at the cell level of the experimental animal are required. .
In addition, these experimental organisms are often observed alive, and the experimental organisms may move, so there is a case where an individual who has been observed may be lost if switching from low magnification to high magnification is not performed instantaneously.

  In the fluorescence observation of the stereomicroscope, the fluorescence of the experimental animal is checked by visual observation. Therefore, it is possible to select the specimen more efficiently if a bright fluorescence image is obtained. Therefore, for example, in the stereomicroscope shown in FIG. 2, it is necessary to increase the numerical aperture (NA) determined by the lens diameters of the objective lens 2 and the variable magnification optical system 3a so that the specimen can be observed more brightly. If an objective lens having a short focal length is used, the NA can be increased. Therefore, if an objective lens having a plurality of magnifications is prepared, observation can be performed with a high NA from a low magnification to a high magnification.

  Japanese Patent Laid-Open No. 10-26729 discloses different objective lenses having the same magnification and the same magnification. If the focal length is the same for objective lenses with different magnifications, it is not necessary to refocus when the objective lens is switched by a revolver or the like, and the workability is greatly improved. However, the magnification of the objective lens with the same focal distance disclosed in JP-A-10-26729 is 1 × objective lens and 0.5 × objective lens, and the magnification exceeding 1 × necessary for the fluorescence check at the cell level. There is no disclosure of a confocal distance objective lens.

Japanese Patent Application Laid-Open No. 2004-54259 discloses a stereomicroscope objective lens that has a high magnification and is observed without vignetting. However, Japanese Patent Laid-Open No. 2004-54259 does not mention anything about the focal distance between the objective lenses.

The present invention has been made in view of the above, and an object of the present invention is to provide a stereomicroscope capable of observing a bright image with good operability and the same focal length with a plurality of objective lenses from low magnification to high magnification. And

In order to solve the above-described problems and achieve the object, an objective lens that converts light from an object into an afocal beam and two zoom observation optics that receive the light emitted from the objective lens and form left and right images In a single-objective binocular stereomicroscope equipped with a system, an objective lens switching mechanism capable of mounting at least two objective lenses is provided,
The focal distance of at least two objective lenses is constant,
The following conditions (1), that satisfy (2), (3) meets, parfocal distance the diameter of the distal end portion of the lens on the most short focal length objective lens at a constant is less than the condition (5) A feature stereo microscope.
(1) fa / fb ≧ 2
(2) 1.4 <| L / fav | <2.2
(3) D / fb ≧ 0.6
(5) R <1.9 × sin (α + θ) × WD
Here, fa represents the focal length of the objective lens having the longest focal length among the objective lenses having the constant focal length, and fb represents the focal length of the objective lens having the shortest focal length among the objective lenses having the constant focal length. L is parfocal distance, Retweeted average focal length of fa and fb, D will indicate the effective diameter of the most objective side lens of the zoom observation optical system, R represents the lens radius of the cutting edge portion, WD is the This is the working distance of the objective lens with the shortest focal length.
θ and α are expressed by the following equations.
(6) θ = sin −1 (NA / n)
(7) α = sin −1 (l / (2 × fb))
l is the distance between the optical axes of the variable magnification optical system, and NA is the NA of the objective lens with the shortest focal length. n represents the refractive index of the medium between the objective lens and the sample.

A stereomicroscope according to claim 2 is characterized in that, in the above invention, the stereomicroscope according to claim 1 satisfies the following conditional expression: (4) fa / fb ≧ 2.5

  According to the stereomicroscope according to the present invention, it is possible to perform observation with good workability with a constant focal distance of the objective lens in a wide magnification range from low magnification to high magnification.

Preferred embodiments of a stereomicroscope according to the present invention will be described below in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments. In the description of the drawings, the same parts are denoted by the same reference numerals. Furthermore, in the drawings to be referred to, an XY coordinate system set for convenience with respect to the stereomicroscope according to the present invention is appropriately attached and shown.

(Embodiment)
First, a stereomicroscope according to an embodiment of the present invention will be described. FIG. 1 is a diagram illustrating a main configuration of a stereomicroscope according to the present embodiment. As shown in FIG. 1, the stereomicroscope of the present embodiment includes two low-magnification objective lenses 2, a high-magnification objective lens 11, and two objective lenses on an illumination base 1 having an illumination optical system inside. A switchable revolver 9, a zoom lens body 3 as a zoom unit, a focusing mechanism 4, a binocular body lens barrel 5 as a lens barrel unit, and a binocular eyepiece 6 are provided.

  The zoom lens body 3 is provided on the illumination base 1 via the focusing mechanism 4, the objective lens 2 is attached to the bottom, and the binocular stereo barrel 5 and the eyepiece 6 are mounted on the top. In addition, the zoom lens body 3 is provided with two variable power optical systems, and the variable power optical system is interlocked with the rotation operation of the zoom handle 3h protruding from the side surface of the zoom lens body 3. And zoomed.

  The focusing mechanism 4 is configured by using a fixed portion 4a fixed to a support portion 7 protruding on the illumination base 1 and a movable portion 4b attached to the fixed portion 4a so as to be movable up and down. . The fixed portion 4a and the movable portion 4b are engaged by a rack and pinion (not shown), and the movable portion 4b is interlocked with the turning operation of the focusing handle 4c projecting from the side surface thereof, and is fixed to the fixed portion 4a. Move up and down. As a result, the focusing mechanism 4 moves the objective lens 2, the binocular stereo barrel 5 and the eyepiece lens 6 together with the zoom lens body 3 attached to the movable portion 4b to perform focusing on the specimen SP.

  The specimen SP is placed on the glass plate 8 fitted on the upper surface portion of the illumination base 1 and is arranged in the vicinity of the optical axis OA of the objective lens 2 and is provided in the illumination base 1 and is not shown. Transmission illumination is performed using an optical system. The illuminated specimen SP is observed through the objective lens 2, the zoom lens body 3, the binocular stereo barrel 5 and the eyepiece lens 6.

  Next, an optical system provided in the stereomicroscope of the present embodiment will be described. FIG. 2 is a diagram illustrating a configuration of a main part of an optical system provided in the zoom lens body 3 and the binocular stereo barrel 5.

As shown in FIG. 2, the zoom lens body 3 includes two afocal variable magnification optical systems 3L and 3R capable of zoom variable magnification. The variable magnification optical systems 3L and 3R are both configured using lenses 3a to 3c, and each incident parallel light beam is converted into a parallel light beam having a different light beam diameter and emitted. The variable magnification optical systems 3L and 3R are arranged in parallel in the X-axis direction symmetrically with respect to the optical axis OA of the objective lens 2, and the distance L1 between the optical axes OL1 and OR1 is the observation of the specimen SP. For example, the value is set at 32 mm as a value suitable for stereoscopic viewing.

In a stereomicroscope, the NA is maximized when the magnification of the zoom optical system is maximum, and the NA at that time is expressed by the following equation.
(8) NA = D / (2 × f)
Here, D is the effective diameter of the lens closest to the objective lens for zoom magnification, and corresponds to the effective diameter of 3a in FIG. f indicates the focal length of the objective lens. As shown in equation (6), in order to secure a large NA for bright image observation, it is necessary to increase the lens diameter of the zoom variable power optical system or shorten the focal length of the objective lens. However, if the lens diameter of the zoom variable-power optical system is made too large, the diameter of the objective lens becomes large and the workability on the specimen deteriorates, so there is a limit to increasing D. Therefore, in order to widen the zooming range and perform bright image observation with good workability, it is desirable to switch the objective lens having a plurality of focal lengths while increasing D to some extent.

In the present embodiment, objective lenses having the following magnifications can be used, and the same in-focus state is the same, so there is no need to refocus when attached to a revolver and converted in magnification. Since the high-power objective lens has a short working distance, the operability of the sample tends to deteriorate. For this reason, the high-magnification objective lens 11 has a tapered tip, which improves the workability of the specimen. In the embodiment, the focal length of the 1 × objective lens is 100 mm. The focal length of each objective lens is 180 mm, and the lens diameter of the front lens of the variable power lens is designed to be Φ31.25.

Table 1. Objective lens of embodiment

表３．１×対物レンズのレンズデータ

表４．１．６×対物レンズのレンズデータ

表５．２×対物レンズのデータ

本実施の形態では０．５×対物レンズと１×対物レンズ、１．６×対物レンズと２×対物レンズの同焦がすべて揃っているため、標本全体の観察から細胞レベルまでの高倍率観察まで対物レンズの倍率を切替えたときのピント合わせが必要なく、作業性の良い観察が可能となる。 Lens data of the objective lens according to the present embodiment is shown below. Each is tracking data from the specimen surface. 3 to 6 are external views of the lens, and FIGS. 7 to 10 are lateral spherical aberration diagrams at the respective zoom maximum magnifications. In the aberration diagrams, a solid line represents 587.56 nm, a dotted line represents 656.27 nm, a one-dot chain line represents 486.13 nm, and a broken line represents an aberration having a wavelength of 435.84 nm.

Table 2. Lens data of 0.5 × objective lens

Table 3.1 Lens data of objective lens

Table 4. Lens data of 1.6 × objective lens

Table 5.2 x Objective lens data

In this embodiment, the 0.5 × objective lens and 1 × objective lens, and the 1.6 × objective lens and 2 × objective lens are all in focus. It is not necessary to focus when the magnification of the objective lens is switched, and observation with good workability is possible.

（５）式は同焦距離が等しい対物レンズのうち最も高倍率の対物レンズの先端部を細くして作業性を向上させるための条件である。高倍率の対物レンズは作動距離が短くなるため、標本の作業性や標本の視認性が悪くなる。実体顕微鏡では最も標本側のレンズの径はズーム変倍光学系を最低倍率にしたときの光線径にて決まる。（５）式の範囲に入ると、ズームレンズの最低倍率の光線径よりも先端部のレンズの径が小さくなり、ズーム最低倍率で視野がけられることとなる。しかし、本実施の形態は同焦距離が一致した低倍率の対物レンズを切替可能なため、低倍率観察は例えば０．５×対物レンズで観察し、高倍率での観察は２×対物レンズで観察するようにすれば問題ない。
２×対物レンズの先端部の断面図を図１１に示す。図１１の先端部の接合レンズ25はそれより像側の単レンズ26に比べ外径を小さくして先端部が細くなるようにしている。また対物レンズ先端部にはテーパー状のカバー27が取り付けられており、カバー27により先端部の凹凸がなく標本面への作業性を向上させる。 The objective lens according to the present embodiment satisfies the following conditional expression.
(1) fa / fb ≧ 2
(2) 1.4 <| L / fav | <2.2
(3) D / fb ≧ 0.6
The formula (1) is, for example, 2 when 0.5 × objective lens and 1 × objective lens are used, and 4 when 0.5 × objective lens and 2 × objective lens are used. Below this conditional expression, the difference in magnification at the time of switching of the objective lens decreases, and it becomes impossible to deal with a wide range from low magnification to high magnification.
If the range of the expression (1) is wide, the difference in conversion magnification at the time of switching of the objective lens becomes large, so it is desirable to satisfy the following expression (4).
(4) fa / fb ≧ 2.5

In the formula (2), L = 180, and fav is an average focal length of 0.5 × objective lens and 2 × objective lens, which is 125, which is 1.44. If the lower limit of this conditional expression is not reached, confocality becomes shorter with respect to the focal length, and it becomes difficult to achieve the same focal point in a low-magnification objective lens having a long focal length. Exceeding the upper limit is advantageous in securing the working distance of the objective lens and designing a low-magnification objective lens, but the position of the eyepiece due to the length of the objective lens itself becomes too higher than the desk surface, resulting in poor workability.
For the same reason, it is desirable to satisfy the following conditional expression.
(2 ′) 1.3 <| L / fav | <1.7
Equation (3) is a condition that enables bright observation. In the present embodiment, D = 31.25 mm, and fb is 2 × the focal length of the objective lens is 50 mm, which is 0.625. Below this lower limit, the NA of the objective lens cannot be increased, and the effect of switching the magnification of the objective lens is reduced.


Further, the 2 × objective lens of the present embodiment satisfies the following conditional expression.
(5) R <1.9 × sin (α + θ) × WD
Here, R is the lens radius of the foremost part, α is the inward angle of the objective lens, and θ is the light beam capture angle determined by the NA of the objective lens, and is expressed by the following equation.
(6) θ = sin −1 (NA / n)
NA is the NA of the objective lens, n is the refractive index of the medium between the objective lens and the sample surface, and is usually 1 in a stereomicroscope. In this embodiment, since NA is 0.3, θ is 17.46 degrees.
The inward angle α is expressed by the following formula.
(9) α = sin −1 ( l / (2 × fob))
l is the distance between the optical axes, 32 in the present embodiment, fob is the focal length of the objective lens, 50 in the present embodiment is 2 × the focal length of the objective lens, and α is 18.66 degrees. Become. For this reason, in this Embodiment, the left side of (5) Formula is 21.43 and R is 25.5 mm.

Table 6. 2 × objective lens data of this embodiment

Expression (5) is a condition for improving workability by narrowing the tip of the objective lens with the highest magnification among objective lenses having the same focal distance. Since the high-power objective lens has a short working distance, the workability of the specimen and the visibility of the specimen deteriorate. In the stereomicroscope, the diameter of the lens on the most specimen side is determined by the light beam diameter when the zoom magnification optical system is set to the minimum magnification. When entering the range of the expression (5), the diameter of the lens at the tip is smaller than the diameter of the light beam at the minimum magnification of the zoom lens, and the field of view can be set at the minimum zoom magnification. However, since the low magnification objective lens having the same focal distance can be switched in this embodiment, the low magnification observation is performed with, for example, a 0.5 × objective lens, and the high magnification observation is performed with a 2 × objective lens. There is no problem if you observe.
A cross-sectional view of the tip of the 2 × objective lens is shown in FIG. The cemented lens 25 at the distal end in FIG. 11 has a smaller outer diameter than the single lens 26 on the image side so that the distal end is thinner. Further, a tapered cover 27 is attached to the distal end portion of the objective lens, and the cover 27 has no irregularities on the distal end portion and improves workability on the specimen surface.

(Appendix 1)
The stereomicroscope according to appendix 1, characterized in that there are three or more types of objective lenses having a constant focal distance (appendix 2)
The stereomicroscope according to appendix 1, wherein a stereomicroscope characterized by satisfying the following conditions: (2 ″) 1.3 <| L / fav | <1.7
(Appendix 3)
The stereomicroscope according to appendix 3, wherein a tip portion of the objective lens having the shortest focal length is provided with a tapered portion with a thin specimen side and a thick image side.

It is a figure which shows the structure of the stereomicroscope concerning embodiment of this invention. It is a figure which shows the structure of the optical system with which the stereomicroscope shown in FIG. 1 is provided. It is sectional drawing of the 0.5 * objective lens of embodiment of this invention. It is sectional drawing of the 1 * objective lens of embodiment of this invention. It is sectional drawing of the 1.6 * objective lens of embodiment of this invention. It is sectional drawing of the 2 * objective lens of embodiment of this invention. FIG. 5 is a longitudinal spherical aberration diagram at the maximum zoom magnification of 0.5 × objective lens. FIG. 6 is a longitudinal spherical aberration diagram when the zoom of the 1 × objective lens is at the maximum magnification. FIG. 6 is a longitudinal spherical aberration diagram at the time of 1.6 × objective lens zoom maximum magnification. FIG. 3 is a longitudinal spherical aberration diagram of the 2 × objective lens at the maximum zoom magnification. It is sectional drawing of the front-end | tip part of 2x objective lens. It is a figure which shows the structure of a stereomicroscope.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Illumination stand 2,11 Objective lens 3 Zoom lens body 3L, 3R Variable magnification optical system 3a-3c Lens 3h Zoom handle 4 Focusing mechanism 4a Fixed part 4b Movable part 4c Focusing handle 5 Binocular stereo barrel 5La, 5Ra Imaging Lens 6 Eyepiece 7 Support unit 8 Glass plate 21 Glass plate 23 Zoom lens body 24 Lens barrel 24L, 24R Imaging optical system 24La, 24Ra Imaging lens 24Lb, 24Rb Prism 24Lc, 24Rc Eyepiece lens L Optical axis distance OA, OL1 , OL2, OR1, optical axis SP, SP ′ sample 25 2 × objective lens tip lens 26 2 × single lens of objective lens 27 2 × objective lens cover

Claims (4)

In a single objective binocular stereomicroscope having an objective lens that converts light from an object into an afocal beam and two zoom observation optical systems that receive the light emitted from the objective lens and form left and right images, at least 2 It has an objective lens switching mechanism that can be equipped with two objective lenses,
The focal distance of at least two objective lenses is constant,
The following conditions (1), that satisfy (2), (3) meets, parfocal distance the diameter of the distal end portion of the lens on the most short focal length objective lens at a constant is less than the condition (5) A feature stereo microscope.
(1) fa / fb ≧ 2
(2) 1.4 <| L / fav | <2.2
(3) D / fb ≧ 0.6
(5) R <1.9 × sin (α + θ) × WD
Here, fa represents the focal length of the objective lens having the longest focal length among the objective lenses having the constant focal length, and fb represents the focal length of the objective lens having the shortest focal length among the objective lenses having the constant focal length. L is parfocal distance, Retweeted average focal length of fa and fb, D will indicate the effective diameter of the most objective side lens of the zoom observation optical system, R represents the lens radius of the cutting edge portion, WD is the This is the working distance of the objective lens with the shortest focal length.
θ and α are expressed by the following equations.
(6) θ = sin −1 (NA / n)
(7) α = sin −1 (l / (2 × fb))
l is the distance between the optical axes of the variable magnification optical system, and NA is the NA of the objective lens with the shortest focal length. n represents the refractive index of the medium between the objective lens and the sample. The stereomicroscope according to claim 1, wherein the following conditional expression is satisfied .
・ Fa / fb ≧ 2.5 2. The stereomicroscope according to claim 1, wherein there are three or more types of objective lenses having a constant focal distance. 2. The stereomicroscope according to claim 1, wherein a tip portion of the objective lens having the shortest focal length is provided with a tapered portion with a thin specimen side and a thick image side.

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