JPS63139316A - Vertical illuminating device for dark field of microscope - Google Patents

Abstract

PURPOSE:To eliminate the light quantity shortage in the vicinity of an observation field, and to improve the focusing performance by placing a ring-shaped parallel deflecting member for reducing the diameter of a ring-shaped parallel illuminating luminous flux, between a perforated mirror of a field illuminating device and a ring-shaped lens or a ring-shaped mirror. CONSTITUTION:An infinity correcting and observing optical system is applied to a microscope, an objective lens 6 is placed in the center part of its objective lens barrel 5, and in its peripheral part, a ring-shaped condensing lens 7 is placed. Also, on the lens 7, a perforated mirror 8 is placed, and an illuminating light from a light source 4 is deflected to the upper part of the lens 7. Moreover, by a light shielding cylinder 9 placed in the center hole of the mirror 8, mixing of a ring-shaped observing light into an observing optical path is prevented, and the generation of a flare is prevented by a diaphragm 10. Between this mirror 8 and the lens 7 a ring-shaped parallel deflecting part 15 is placed, and two reflecting surfaces 15a, 15b opposed in parallel to each other to said part are provided. In such a way, the diameter of a ring-shaped parallel illuminating optical flux is reduced, and the light quantity in the periphery of an observing field is compensated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an epi-dark field illumination device for a microscope equipped with an infinity corrected observation optical system.

[Prior Art and Problems to be Solved by the Invention] It is well known that the observation optical system of a metallurgical microscope should be an infinity correction optical system.

In other words, by adopting an infinity correction optical system, the light beam between the objective lens and the imaging lens becomes a parallel light beam, and even if an attachment or half mirror is inserted between them, it will not affect the magnification and imaging performance. It has the advantage of not coming out.

Although the infinity correcting optical system has various advantages as described above, the objective lens is equipped with a helmet N in order to further improve the resolution performance.
, A. As the number of microscopes has increased, and it has become necessary to attach a large number of attachments for special microscopy, the problem of insufficient light around the observation field has arisen.

To explain this based on the principle diagram in Fig. 4, 1 is the object plane, 2 is the objective lens, and 3 is the diaphragm. In the case of an infinity correction optical system, the rays emitted from the center of the observation field are 4a and 4b. ,
4c, the rays travel parallel to the optical axis O, but the rays emitted from the periphery of the observation field are 5a.

The light travels obliquely to the optical axis O as shown in 5b and 5c.

Therefore, if there is an aperture 3 in the middle, all the light rays from the center of the field of view will pass through, but most of the light rays at the periphery of the field of view will be vignetted by the aperture 3, so the image will become darker towards the periphery of the field of view, so-called peripheral illumination. There will be a shortage. and,
This tendency becomes stronger as the position of the aperture 3 moves away from the objective lens 2 (comparison of shapes la and b), and the N of the objective lens 2.

Even if Δ becomes large, this tendency will become stronger.

Therefore, in order to solve this problem, it is possible to increase the aperture diameter and make the observation optical path thicker, but as will be explained in detail below, it is extremely difficult to do so in this type of conventional epi-illumination dark-field illumination device.

FIG. 5 shows the optical system of this type of conventional epi-illuminated dark-field illumination device, where 5 is an objective lens barrel, the objective lens 6 is located at the center of the barrel, and the ring-shaped condenser is located at the periphery. Lenses 7 are arranged respectively. 8 is a ring-shaped perforated mirror arranged above the ring-shaped condensing lens 7 and deflects the illumination light toward the condensing lens 7; 9 is the center hole of the perforated mirror 8 above the objective lens 5; a light-shielding tube that is placed in the observation optical path to prevent ring-shaped illumination light from entering the observation optical path;
Reference numeral 10 denotes a diaphragm that is provided within the light-shielding tube 9 and prevents flare from occurring within the light-shielding tube 9.

11, 12, and 13 are illumination lenses, and 14 is a light source. The illumination light emitted from the light source 14 is transmitted to the illumination lens 13.12.
．． 11, the illumination light becomes a parallel beam of light and enters the perforated mirror 8, and after being reflected by the perforated mirror 8, it becomes a ring-shaped parallel beam of illumination light that enters the ring-shaped condensing lens 7 and is directed onto the object surface 1. The condensed light emitted from the object plane l is converted into a parallel beam by the substitute lens 6, passes through the light-shielding tube 9, and is made incident on an imaging lens (not shown).

direction, the attachment is inserted into the parallel beam part,
As a result, if the distance between the objective lens 6 and the diaphragm 10 increases, an insufficient amount of light will occur around the observation field of view based on the principle shown in FIG.

As mentioned above, the optical system of a conventional epi-illuminated darkfield illumination device is
Since the ring-shaped illumination optical path and the observation optical path are separated to prevent the ring-shaped illumination light from entering the observation optical path, the observation optical path 11 is restricted by the inner diameter of the perforated mirror 8, and the observation optical path is It was extremely difficult to make it thicker.

In order to avoid the phenomenon of insufficient light intensity around the observation field of view, it is necessary to adopt a finite distance correction optical system or to
It is conceivable to use a configuration in which the illumination light intersects behind the objective lens, as in the device described in Japanese Patent No. 5483, but adopting a finite correction optical system is not only a step backward in technology; There is a problem that the magnification becomes incorrect when the optical path length is increased by inserting an attachment, and various restrictions occur when the illumination light is crossed, making it difficult to design a device that can fully demonstrate its performance.

In view of the above-mentioned problems, the present invention employs an infinity correction optical system having various advantages as an observation optical system, while also reducing the high N and A of the objective lens. The object of the present invention is to provide an epi-illuminated dark-field illumination device that does not cause insufficient light intensity around the observation field even when a large number of attachments are installed for special microscopy or special microscopy.

[Means and effects for solving the problem] The epi-illuminated dark field illumination device according to the present invention is applied to a microscope equipped with an infinity corrected observation optical system, and has a hole provided with a center hole through which the observation light beam from the objective lens passes. In an epi-illuminated dark-field illumination device in which a ring-shaped collimated illumination beam is deflected toward a ring-shaped lens or a ring-shaped mirror disposed around an objective lens by a perforated mirror, the perforated mirror and the ring-shaped lens or A ring-shaped parallel deflection member for reducing the diameter of the ring-shaped parallel illumination beam is disposed between the ring-shaped mirror and the center hole of the perforated mirror can be configured to have a large diameter.

(Embodiment) Hereinafter, the present invention will be described in detail based on the illustrated embodiment, with the same reference numerals given to the same members as in the conventional example shown in FIG.

FIG. 1 shows a first embodiment, in which reference numeral 15 denotes a ring-shaped parallel deflection member such as a ring-shaped prism placed between the perforated mirror 8 and the ring-shaped condensing lens 7. Two reflective surfaces 15a in the shape of truncated conical sides facing in parallel
, 15b, which have the function of reducing the diameter of the ring-shaped parallel illumination beam from the perforated mirror 8 and allowing the ring-shaped parallel illumination beam to enter the ring-shaped condenser lens 7 as it is.

Therefore, with this configuration, the center hole of the perforated mirror can be configured to have a large diameter, so that the light-shielding tube 9 and the aperture 10 can be
By increasing the diameter of the observation optical path, the observation optical path can be made thicker. As a result, the objective lens 6 has a high N.

A. Even if many attachments are installed between the objective lens 6 and the diaphragm 10 for special microscopy, there will be no shortage of light around the observation field.The ring-shaped parallel deflection member 15 is made of optical resin. It can be manufactured by injection molding.

FIG. 2 shows the optical system of the second embodiment, which has the same structure as the first embodiment, but also includes a ring-shaped parallel deflection member 16 which is the same as the ring-shaped parallel deflection member 15, and a perforated mirror in the opposite direction. 8 to enlarge the diameter of the ring-shaped parallel illumination light beam incident on the perforated mirror 8.

Therefore, according to this configuration, the illumination lenses 11, 12.1
3 can be made smaller.

FIG. 3 shows the optical system of the third embodiment, which is similar to the second embodiment.
In a configuration similar to that of the embodiment, a ring-shaped parallel deflection member 1
5, two reflective surfaces 17a facing each other and consisting of parts of the side surfaces of two parabolic rotating bodies whose focal points coincide;
17b is disposed, and in place of the ring-shaped parallel deflection member 16, a similar ring-shaped parallel deflection member 18 whose ring width is wider toward the center is disposed. Therefore, the ring-shaped parallel deflection member 1
7, since the two reflecting surfaces 17a and 17b have a condensing function in addition to a parallel deflection function, the ring width of the perforated mirror 8 can be increased, and as a result, the illumination lenses 11, 12.
Since the effective cross-sectional area of the collimated illumination beam passing through 13 increases, the observation field can be brightened. Furthermore, since the ring width of the ring-shaped parallel deflection member 18 is wider toward the center, it becomes possible to utilize the light beam closer to the center of the parallel illumination light beam passing through the illumination lens 11, 12, 13, and as a result, the observation The field of view can be made even brighter, and the diameters of the illumination lenses 11, 12, 13 can also be made smaller.

In any of the embodiments described above, other ring-shaped lenses may be used in place of the ring-shaped condensing lens 7, or a ring-shaped mirror having a truncated conical side surface-shaped reflective surface may be used.

〔Effect of the invention〕

As mentioned above, the epi-illuminated dark-field illumination device according to the present invention is based on the premise that an infinity correction optical system is adopted as the observation optical system, and also has a number of features such as high N and A of the objective lens and special microscopy. It has a practically important advantage of not causing insufficient light amount around the 1tlt viewing field even if an attachment is attached.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the optical system of the first embodiment of the epi-illuminated dark field illumination device according to the present invention, FIGS. 2 and 3 are diagrams showing the optical system of the second and third embodiments, respectively, and FIG. This figure shows the principle of occurrence of insufficient light amount around the ttU observation field in the infinity corrected observation optical system, and FIG. 5 is a diagram showing a conventional optical system. 1...Object plane, 5...Objective lens barrel, 6...
...Objective lens, 7..., ring-shaped condensing lens, 8.
...Perforated mirror, 9...Shading tube, 10...
Aperture, 11.12.13...Illumination lens, 14...
...Light source, 15.16.17.18...Ring-shaped parallel deflection member. 1PI Illustration 2 Figure 1F3 Figure 1F4 Figure 1-5

Claims (4)

[Claims] (1) Applicable to a microscope equipped with an infinity-corrected observation optical system, a ring-shaped parallel illumination beam is arranged around the objective lens using a perforated mirror with a central hole through which the observation beam from the objective lens passes. In an epi-illuminated dark field illumination device that is deflected toward a shaped lens or a ring shaped mirror,
An epi-illumination dark-field illumination device characterized in that a ring-shaped parallel deflection member for reducing the diameter of the ring-shaped parallel illumination beam is disposed between the perforated mirror and the ring-shaped lens or ring-shaped mirror. (2) The epi-illumination dark-field illumination device according to claim (1), further comprising another ring-shaped parallel deflection member arranged in front of the perforated mirror to enlarge the diameter of the parallel illumination beam. (3) The epi-illumination dark-field illumination device according to claim (2), wherein the ring width of the ring-shaped parallel deflection member disposed in front of the perforated mirror is widened toward the center. (4) The epi-illumination dark-field illumination device according to any one of claims (1) to (3), wherein the ring-shaped parallel deflection member also has light condensing properties.