JPH0486614A - Illuminating device for microscope - Google Patents

Abstract

PURPOSE:To facilitate the execution of alternate illumination and simultaneous illumination by different illumination systems with simple constitution and to obtain a sufficient illuminating light quantity by selecting an arbitrary illuminating optical path from plural illuminating optical paths and shutting off the other illuminating optical paths by an optical path shutting off means. CONSTITUTION:A sector 25 is inserted between a light source 21 and a collector lens 23 to shut off the incident of the light from the light source 21 to the dark field illuminating optical path in the case of execution of vertical bright field illumination. In addition, the image of the light source 21 is projected to the pupil of a bright field condenser lens 28 and a sample S is subjected to vertical bright field illumination when a sector 24 is removed from between the light source 21 and the collector lens 22. The setting of the sectors 24, 25 is reversed from the case of the vertical bright field illumination in the case of vertical dark field illumination. The alternate illumination and simultaneous illumination of the vertical bright field illumination and vertical dark field illumination are exectued by selectively inserting and removing the sectors 24, 25 in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a microscope illumination device, and more particularly to a microscope illumination device capable of alternate illumination or simultaneous illumination using a plurality of illumination methods.

[Conventional technology]

Traditionally, as a method for illuminating specimens during microscopic observation,
Epi-illumination methods for observing reflected light from a specimen and transmitted illumination methods for observing transmitted light from a specimen are known, and each illumination method further includes bright-field illumination, dark-field illumination, phase contrast illumination, It is classified into polarized illumination, fluorescent illumination, differential interference illumination, etc.

Some illumination devices for illuminating specimens to be observed under a microscope are capable of using a plurality of these illumination methods in combination.

Combined illumination that uses multiple illumination methods includes selectively and alternately observing a single specimen using multiple illumination methods;
Simultaneous lighting may be performed using multiple lighting methods. For example, an example of using a combination of epi-illuminated bright-field illumination and epi-illuminated dark-field illumination is surface inspection of an IC wafer. This can improve inspection accuracy and inspection workability by selectively using observation of direct reflected light using epi-illuminated bright-field illumination and observation of scattered reflected light using epi-illuminated dark-field illumination depending on the wafer pattern. Furthermore, an example of applying the combination of epifluorescence illumination and transmitted phase contrast illumination is observation of cultured cells. This allows the observation of cell nuclei stained with fluorescent dyes using epifluorescence illumination, and the clear observation of cell outlines (cell membranes) using transmitted phase contrast illumination, making it possible to clearly separate and observe the positions of both. .

The optical system of the illumination device that enables this kind of combined illumination is the fifth
As shown in FIG.

The illumination device shown in FIG. 5 is an apparatus that realizes combined illumination of epi-illuminated bright-field illumination and epi-illuminated dark-field illumination.

This illumination device uses a luminous flux near the center of a luminous flux emitted from one light source 1 for bright-field illumination, and uses a peripheral ring-shaped luminous flux for dark-field illumination. Therefore, when bright-field illumination is performed, the light beam emitted from the light source 1 is made incident on the half mirror 4 arranged on the optical path between the objective lens 2 and the eyepiece lens 3, and the light beam reflected here is transmitted to the objective lens 2. bright-field illumination of the specimen S. In addition, when performing dark field illumination, a ring-shaped perforated mirror 5 with a hole formed in the center is placed in place of the half mirror 4, and the luminous flux near the center of the luminous flux emitted from the light source is The light beam is transmitted and only the peripheral part of the light beam is reflected and made to enter the objective lens 2.
The specimen S is illuminated with dark field illumination.

Switching between the half mirror 4 and the perforated mirror 5 is performed by a dedicated switching mechanism provided separately.

Further, FIG. 6 shows an illumination device that enables both epi-illumination and transmitted illumination.

This illumination device emits light from a light source 1 and a collector lens 1.
The light beam focused at 0 is separated by a half mirror 11 into reflected light and transmitted light. The light beam reflected by the half mirror 11 is reflected by the mirror 12 and enters the half mirror 15 arranged on the optical axis of the eyepiece lens 13 and the objective lens 14. The light reflected by this half mirror 15 enters the objective lens 14 to epi-illuminate the sample S.

On the other hand, the light beam transmitted by the half mirror 11 is reflected by the mirror 16 and illuminates the specimen S from the back surface, and the transmitted light enters the objective lens 14 and is observed by the eyepiece lens 13.

[Invention or problem to be solved]

However, when a switching mechanism is required to switch the illumination optical path according to the lighting method, as in the above-mentioned lighting device, the structure becomes complicated and the cost increases. However, if a switching mechanism is required, there is a problem that the switching mechanism cannot simultaneously illuminate various types of lights.

Further, as shown in FIG. 6, a plurality of half mirrors 11,
Since the optical path is divided by 15, it is not possible to obtain a sufficient amount of illumination light, which may become an obstacle to good microscopic observation.

The present invention has been made in view of the above-mentioned circumstances, and provides a microscope illumination device that has a simple configuration, can perform alternate illumination or simultaneous illumination using different illumination methods, and can easily obtain a sufficient amount of illumination light. The purpose is to provide

[Means to solve the problem]

In order to achieve the above object, a microscope illumination device according to the present invention is compatible with a plurality of illumination methods used in a microscope illumination device that alternately or simultaneously illuminates a specimen to be observed under a microscope using a plurality of illumination methods. a plurality of light condensing members arranged around the light source, a plurality of illumination optical paths each guiding the light beams condensed by the light condensing members to the specimen as illumination light, and each of the illumination light paths being appropriately shielded from light. It is equipped with a plurality of optical path blocking means.

[For production]

By taking the above measures, the present invention selects an arbitrary illumination optical path from a plurality of illumination optical paths and blocks the other illumination optical paths with the optical path shading means, so that illumination by any illumination method can be performed. It will be done. Furthermore, simultaneous illumination is possible by selecting any two illumination optical paths and blocking the other illumination optical paths. Therefore, since the light from the light source is not divided into a plurality of illumination optical paths, a sufficient amount of light can be obtained.

Further, since any illumination method can be used by simply blocking a predetermined illumination optical path, there is no need for a switching mechanism for switching between a half mirror and a perforated mirror, simplifying the configuration.

〔Example〕

Examples of the present invention will be described below.

As a first embodiment of the present invention, an illumination device that uses both epi-illuminated bright-field illumination and epi-illuminated dark-field illumination of a microscope will be described.

FIG. 1 is a diagram showing a first embodiment. Code 2 shown in the same figure
0 is the lamp house. Inside the lamp house 20, there is a light source 21 made of, for example, a halogen lamp, and two collector lenses 22.2 arranged around the light source 21.
3 are arranged. Furthermore, in lamp house 20,
A sector 24 serving as a light shielding means is removably installed between the light source 21 and the collector lens 22, and a sector 25 is removably installed between the light source 21 and the collector lens 23. Note that when each sector 24.25 is inserted between the light source 20 and each collector lens 24.25, the incidence of light to each corresponding collector lens 24.25 is blocked.

The collector lens 22 has a diameter necessary for the illumination numerical aperture of bright field illumination. This collector lens 22 serves as an incident end of a bright-field illumination optical path, and the light beam condensed by the collector lens 22 is incident on an illumination lens group 26 for realizing Koehler illumination. A half mirror 27 is arranged opposite to the exit end of this lens group 26. The half mirror 27 is arranged on the optical axis of the bright field condenser lens 28 and the eyepiece lens 29 of the microscope, and
The bright field condenser lens 28 is arranged such that a reflected component of the luminous flux from the bright field condenser lens 28 enters the bright field condenser lens 28.

On the other hand, the collector lens 23 has a diameter necessary for the illumination numerical aperture of dark field illumination. The collector lens 23 serves as the incident end of the dark-field illumination optical path, and focuses the light emitted from the light source 21 onto the incident end of the light guide 30. The output end of the light guide 30 is formed in a ring shape,
It is arranged opposite to a ring-shaped lens 32 that has a light-condensing function. The ring-shaped lens 32 is disposed at one end of the objective lens 33 and acts to cause dark-field illumination light to enter a dark-field mirror 34 provided near the other end within the objective lens 33. The dark field mirror 34 is formed to ensure the necessary illumination according to the observation field and the numerical aperture of the objective lens 33, and is adjusted so that the incident dark field illumination light is projected onto the specimen S. There is.

The reflected light from the sample S passes through the bright field condenser lens 28 and enters the half mirror 27. The light transmitted through the half mirror 27 passes through the imaging lens 35. The light is guided to the eyepiece lens 29 via the barrel prism 36.

Next, the operation of the lighting device configured in this way will be explained.

When performing epi-illuminated bright field illumination, the sector 25 is connected to the light source 21.
The sector 24 is inserted between the light source 21 and the collector lens 23 to block the light from the light source 21 from entering the dark-field illumination optical path, and the sector 24 is removed from between the light source 21 and the collector lens 22. As a result, the light emitted from the light source 21 enters only the collector lens 22, which is the incident end of the incident bright field illumination optical path, and the image of the light source 21 is brightened by the illumination lens group 26 and half mirror 27 that achieve Koehler illumination. The light is projected onto the pupil of the field condenser lens 28, and the specimen S is illuminated by epi-illuminated bright field illumination.

When using epi-illumination dark-field illumination, the settings of sectors 24 and 25 are reversed to those for epi-illumination bright-field illumination.

As a result, the light from the light source 21 is focused by the collector lens 23 and enters the light guide 30 whose incident end is disposed near the rear polarized light focusing point of the collector lens 23 . The light emitted from the ring-shaped output end 31 of the light guide 30 is condensed by the ring-shaped lens 32 and projected onto the dark field mirror 34. The specimen S is subjected to epi-dark field illumination by the dark field illumination light that is deflected and condensed by the dark field mirror 34 .

In the epi-illuminated bright-field illumination, the direct reflected light from the specimen S, and in the epi-illuminated dark-field illumination, the scattered light passes through the bright-field condenser lens 28, the half mirror 27, and the imaging lens 35.
．． After passing through the lens barrel prism 36, the image is formed and observed through the eyepiece lens 29.

Furthermore, simultaneous illumination is possible by removing sectors 24 and 25 at the same time.

As described above, according to this embodiment, the light emitted from the light source 21 is transmitted to the collector lens 22 disposed around the light source 21.
By #23, the illumination is directly taken in for each illumination optical path, so it is possible to obtain a sufficient amount of illumination light, and in particular, the brightness during dark field illumination can be greatly improved, and the observation ability of the microscope can be improved. . Further, by selectively inserting and removing the sectors 22 and 23, epi-illuminated bright-field illumination and epi-illuminated dark-field illumination can be alternately or simultaneously illuminated.

Therefore, there is no need to provide a complicated switching mechanism for switching between the half mirror and the perforated mirror, and alternate illumination and simultaneous illumination can be realized with a simple configuration.

Furthermore, in semiconductor inspection, the illumination method for obtaining the optimum contrast of a wafer image differs depending on the circuit pattern of the wafer. Therefore, if this embodiment is applied to Proper, which is a semiconductor inspection device, it is possible to perform alternate illumination and simultaneous illumination of bright field illumination and dark field illumination, so image processing can be performed by switching between bright field illumination and dark field illumination. This makes it possible to select the optimal illumination method and shorten processing time for wafer positioning and surface inspection. Furthermore, since simultaneous bright-field and dark-field illumination is possible, it is possible to observe the surface shape and flaws of low-reflectance specimens such as ceramics with good contrast.

In the above embodiment, by replacing the half mirror 27 with a dichroic mirror and using epi-fluorescent illumination, simultaneous illumination with epi-fluorescent illumination and epi-illuminated dark-field illumination becomes possible. Therefore, when inspecting the resist contamination on the surface of a semiconductor wafer, the fluorescent image of the resist and the dark field image of the IC pattern portion can be superimposed and observed simultaneously. Therefore, it is possible to eliminate the inconvenience of conventionally being able to see only fluorescent images in a dark observation field.

Note that by electrifying the switching of sectors 24 and 25, high-speed switching between bright field illumination and dark field illumination becomes possible.

Figure 2 shows the electric switching mechanism between bright field illumination and dark field illumination. Two rotating plates 42 and 43 are disposed facing each other at a predetermined distance from a rotating shaft 41 of a DC motor 40 having a built-in stepping motor or rotary encoder. Openings 44° 45 are formed in each rotary plate 42.4 at positions 180 degrees apart from each other, and both rotary plates 42.4
The light source 21 is placed between the three rotating plates 42, 43, and the collector lenses 22, 23 are placed with each rotary plate 42, 43 in between.

In such a configuration, by rotating the rotation shaft 41, the opening and closing of the optical path between the light source 21 and the collector lenses 22 and 23 is sequentially switched, and high-speed switching is possible.

A signal synchronized with the rotation axis 41 opens and closes the illumination optical path and
It is possible to obtain the timing for capturing image signals into the V camera.

Next, as a second embodiment of the present invention, an illumination device that enables combined illumination of epi-illuminated bright-field illumination and transmitted bright-field illumination will be described.

FIG. 3 is a diagram showing a lighting device according to a second embodiment.

Note that parts having the same functions as those of the apparatus shown in FIG. 1 are given the same reference numerals.

Since the optical system for epi-illuminated bright-field illumination in this embodiment is the same as that in the first embodiment, only the configuration for transmitted bright-field illumination will be described in detail here. One collector lens 23 disposed around the light source 21 serves as an incident end of the transmission bright field illumination optical path. The light beam collected by the collector lens 23 is incident on one end of the light guide 50. A collector lens 51 is arranged at the output end of the light guide 50. An illumination lens 52 is arranged on the output side of the collector lens 51, and the light flux passing through the illumination lens 52 is
The light is incident on a condenser lens 56 by a mirror 53 placed on its optical axis. The condenser lens 56 illuminates the specimen S from the back surface by using the luminous flux as transmitted bright-field illumination light.

According to this embodiment, since the light of each illumination is directly taken in from the light source 21 in epi-illumination and transmitted illumination, it is possible to use a conventional illumination device that combines epi-illumination bright field illumination and transmitted bright field illumination. There is no need to divide the luminous flux from the light source as in , and a sufficient amount of illumination light can be obtained. This example enables simultaneous illumination of epi-illuminated bright field illumination and transmitted bright field illumination with sufficient illumination light intensity, so it can be used when photographing tissue specimens with colored backgrounds or when observing semi-transparent specimens with good contrast. It is particularly effective.

In addition, in the above embodiment, an example was shown in which the light guide 50 was used to guide the transmitted bright field illumination light to the specimen S, but the light guide 50 is not limited to such an optical member, and for example, a mirror or a relay lens may be combined. It may be a configuration.

Next, as a third embodiment of the present invention, an illumination device that enables combined illumination by epi-illuminated bright-field illumination, epi-illuminated dark-field illumination, and transmitted bright-field illumination will be described.

FIG. 4 shows the configuration of the optical system of the third embodiment. In addition, the first
Components having the same functions as those of the illumination device shown in the figures and FIG. 3 are given the same reference numerals. In this embodiment, epi-illuminated bright-field illumination and epi-illuminated dark-field illumination are realized with the configuration shown in FIG. Taffeta lenses 60 are arranged. A sector 61 that can be inserted and removed is provided between the light source 21 and the collector lens 60.

The light beam condensed by the collector lens 60 is transmitted to the light guide 6
The light is input to the incident end of No.2. At the output end of the light guide 62, a collector lens 63 is arranged on the optical axis of the objective lens 33.

A condenser lens 56 is disposed on the output side of the collector lens 63, and the specimen S is illuminated from the back side with transmitted bright field illumination light.

According to this embodiment, the first. The same effects as in the second embodiment can be obtained, and furthermore, it is possible to perform alternate illumination or simultaneous illumination by arbitrarily combining three illumination methods: epi-illuminated bright-field illumination, epi-illuminated dark-field illumination, and transmitted bright-field illumination. .

In addition, in each of the first to third embodiments, the lamp house 2
Although a configuration is shown in which light is blocked by inserting a shielding plate between the light source and the collector lens in the sector 24.25.61 provided at 0, the present invention is limited to such a configuration. Instead, the light shielding member may be placed anywhere between the light source and the specimen as long as it can shield any illumination optical path.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to provide a microscope illumination device that can perform alternate illumination or simultaneous illumination using different illumination methods with a simple configuration, and can also obtain a sufficient amount of illumination light.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the first embodiment of the present invention, Fig. 2 is a diagram showing the structure of an electric sector, Fig. 3 is a block diagram of the second embodiment, and Fig. 4 is a block diagram of the third embodiment. Fig. 5 is a block diagram of a conventional illumination device that enables epi-illuminated bright-field illumination and epi-illuminated dark-field illumination, and Fig. 6 shows a conventional illumination device that enables epi-illuminated bright-field illumination and transmitted bright-field illumination. be. 20...Lamp house, 21...Light source, 22゜23
...Collector lens, 24.25...Sector 26
...Illumination lens group, 27... Half mirror 28...
・Bright field condenser lens, 29...Eyepiece, 3
0...Light guide, 31...Ring-shaped output end, 3
2... Ring-shaped lens, 33... Objective lens, 34
...Dark field mirror 2nd figure =) -h: Medium ○

Claims (1)

[Claims] In a microscope illumination device that alternately or simultaneously illuminates a specimen to be observed under a microscope using a plurality of illumination methods, a plurality of illumination systems arranged around a light source corresponding to the plurality of illumination methods used are provided. a plurality of illumination optical paths each guiding the light beams condensed by the respective condensing members to the specimen as illumination light; and a plurality of optical path shading means for appropriately shielding each of the illumination optical paths. A microscope illumination device characterized by: