JP2569641Y2 - Microscope illumination optics - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microscope illumination optical system, and more particularly to a transmission illumination optical system used for observing a transparent sample.

[0002]

2. Description of the Related Art Among Koehler illuminations used as a transmission illumination optical system of a microscope, those configured as a telecentric system project a filament image of a light source onto an aperture stop to form a secondary light source, and a condenser lens. The specimen is illuminated with substantially parallel light so that the front focal point coincides with the secondary light source, and an image of the secondary light source is formed at the rear focal point of the objective lens. The field stop is disposed at a position conjugate with the sample surface. With this configuration, ideal illumination with a small numerical aperture and a large numerical aperture is realized for a low-magnification objective lens with less illumination unevenness for a low-magnification objective lens.

Conventionally, when using Koehler illumination for practical use, the filament size is too small or the filament image is not accurately projected on the aperture stop.
There may be a case where illumination unevenness occurs or it is desired to converge the illumination light of the light source more efficiently. In these cases, a diffuser plate for scattering light or an optical element formed by integrating micro prisms or micro lenses on one surface of a parallel flat plate is arranged in the optical path to obtain a bright and uniform field of view.

[0004]

However, the deterioration of illumination caused by the restrictions on various dimensions such as the lens diameter and the optical path length of the illumination optical system, especially the shortage of the numerical aperture for the high-magnification objective lens. It could not be prevented. For example, the effective diameter of the collector lens closest to the light source cannot be secured, and an illumination optical system satisfying a predetermined numerical aperture of the high-magnification objective lens may not be realized. In this case, if the diffusing plate is arranged in the optical path with a high degree of diffusion, the predetermined numerical aperture can be satisfied, but the brightness is insufficient, and
If an optical element in which micro lenses and the like are integrated is arranged in the optical path, the light source is divided into an infinite number of small light source images, which is effective for illumination unevenness, but is effective for increasing the numerical aperture. Has no effect.

[0005] The present invention has been made in view of the above-mentioned problems of the prior art, and it is an object of the present invention to provide a high-magnification objective lens that has no illumination unevenness for a low-magnification objective lens. On the other hand, it is an object of the present invention to provide a microscope illumination optical system capable of securing a large numerical aperture.

[0006]

In order to achieve the above object, a microscope illumination optical system according to the present invention is arranged such that a first relay lens disposed on an exit side of a collector lens has a lens center area including an optical axis. And an outer peripheral region thereof have different powers.
In addition, the "diffusion element" in the claims of the utility model registration means:
A light scattering member or element, such as an optical element in which minute prisms or minute lenses are integrated on one surface of a ground glass or the above-mentioned parallel flat plate.

[0007]

When illuminating a high-magnification objective lens, the positive power of the outer peripheral region of the relay lens refracts the illumination light from the light source passing through the collector lens so that the effective diameter of the collector lens becomes apparently larger. At least, a critical illumination is constituted by the illumination light passing through the area,
When illuminating the low-magnification objective lens, Koehler illumination is constituted by the central region of the relay lens. Therefore,
An appropriate numerical aperture corresponding to the use magnification can be secured, and a bright visual field without illumination unevenness can be obtained.

[0008]

Embodiments will be described below with reference to the drawings. FIG. 1 is a view showing an optical system and an optical path of illumination light according to a preferred embodiment of the present invention, wherein (a) illuminates a high-magnification objective lens and (b) illuminates a low-magnification objective lens. Each case is shown. In the figure, 1 is a light source composed of a filament, 2 is a sample surface, L1 is a collector lens for converting illumination light from the light source 1 into substantially parallel or convergent light, and P1 is a heat ray absorbing glass. L2 is a first relay lens for relaying the illumination light from the collector lens L1. As shown in the figure, the outer peripheral region Lo is more illuminating light than the central lens region Li including the optical axis O as shown. Is formed so that the power for converging is increased. P2 is a diffusion plate glass for scattering light, Fs is a field stop, L3 is a second relay lens for relaying an image of the field stop Fs, As is an aperture stop,
L4 is an interchangeable condenser lens for forming an image of the field stop Fs on the sample surface 2. It is assumed that the high-magnification objective lens shown in (a) illuminates with NA = 1.4, and the low-magnification objective lens shown in (b) illuminates with NA = 0.4.

Since this embodiment is constructed as described above, when illuminating the high-magnification objective lens, the relay lens L
The illumination light having a large numerical aperture can be guided from the light source 1 side to the sample surface 2 by the positive power of the region Lo of the outer peripheral portion of the sample 2. In this case, since the vicinity of the light source 1 and the sample surface 2 are conjugate, such an illumination optical system forms a critical illumination, and can obtain a bright and clear visual field.

FIG. 2 shows the illumination optical system shown in FIG. 1 in which a parallel planar relay lens L2 'is arranged in place of the relay lens L2, and the same numerical aperture (NA) as in FIG.
= 1.4) and the optical path (indicated by a solid line and a symbol X in the figure) when the illumination light of this numerical aperture is traced backward from the sample surface 2 side. As is clear from FIG. 2, the reverse tracing light X does not reach the light source 1 because the effective diameter of the collector lens L1 is insufficient, and the illumination optical system in this case has an insufficient numerical aperture. In this embodiment, the illumination light from the light source 1 that passes through the collector lens L1 and enters the area Lo is caused by the positive diameter of the area Lo on the outer peripheral portion of the relay lens L2. Since the light is refracted so as to become larger, a desired numerical aperture can be secured. Therefore, in the case where the effective diameter of the collector lens L1 cannot be increased due to the structural limitation of the illumination optical system, it is effective in preventing the deterioration of the illumination caused by the above-described restriction conditions regarding various dimensions of the illumination optical system. It is.

When illuminating a low-magnification objective lens,
All illumination light satisfying a desired numerical aperture passes through the central region Li of the relay lens L2, and this illumination light illuminates the sample surface 2. In the illumination optical system in this case, since the vicinity of the light source 1 and the aperture stop As are conjugate, Koehler illumination can be configured, and a field of view without illumination unevenness can be obtained.

As described above, since the first relay lens L2 has different powers in the region Li at the center of the lens including the optical axis O and the region Lo at the outer periphery thereof, the illumination optical system has It is configured to perform Koehler illumination for the low-magnification objective lens and critical illumination for some of the light beams for the high-magnification objective lens, thereby ensuring a sufficient numerical aperture corresponding to the magnification used. it can. In general, critical illumination is an illumination method in which illumination unevenness is likely to occur. However, since a high-magnification objective lens has a very narrow illumination field, there is no particular problem. Further, according to the configuration of the present invention, not all the luminous flux when illuminating the high-magnification objective lens is critical illumination, but the illumination light for increasing the numerical aperture, that is, the area Lo of the outer peripheral portion of the relay lens L2.
Only the illumination light passing through is the critical illumination.

The area Li at the center of the relay lens L2 through which the illumination light from the light source 1 illuminates the low-magnification objective lens may have a positive or negative power as needed. Also, the relay lens L2 may be formed by a cemented lens.

[0014]

As described above, according to the microscope illumination optical system of the present invention, an appropriate numerical aperture corresponding to the magnification to be used can be secured, there is no illumination unevenness for the low-magnification objective lens, and there is no irregularity for the high-magnification objective lens. As a result, it is possible to obtain a bright visual field with a large numerical aperture and no illumination unevenness.

[Brief description of the drawings]

FIG. 1 is a diagram showing an optical system of an embodiment of a microscope illumination optical system according to the present invention and an optical path of illumination light, wherein (a) illuminates a high-magnification objective lens, and (b) shows a low-magnification objective lens. Are respectively illuminated.

FIG. 2 shows an optical system and a tracing ray when illuminating light is traced back from a sample surface side when a relay lens L2 'is arranged instead of the relay lens L2 in the illumination optical system shown in FIG. FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Light source 2 ... Sample surface As ... Aperture stop Fs ... Field stop L1 ... Collector lens L2 ... 1st relay lens L3 ... 2nd relay lens L4 ... -Condenser lens P1: Heat ray absorbing glass P2: Diffusion plate glass Li: Region at the center Lo: Region at the outer periphery L2 ': Relay lens

Claims (1)

(57) [Scope of request for utility model registration] 1. A light source, a collector lens for converting illumination light from the light source into substantially parallel or convergent light, a first relay lens for relaying illumination light from the collector lens, a field stop, A second relay lens for relaying the image of the field stop, and an exchangeable condenser lens for forming the image of the field stop on the sample surface are sequentially arranged, and the light source is connected to the field stop. In a microscope illumination optical system provided with a diffusing element in an optical path, the first relay lens has different powers in a central region including an optical axis and a peripheral region thereof. Optical system.