JPH0720383A - Transmission type confocal laser microscope - Google Patents

Abstract

PURPOSE:To easily and accurately focus the transmission side objective lens of a transmission type confocal laser microscope in a stable state. CONSTITUTION:The transmission side objective lens 10 under the sample table of the transmission type confocal laser microscope is constituted of an objective lens part 10a capable of moving in an optical axis direction and a relay lens part 10b fixedly arranged, and has such structure that the movement of the lens part 10a does not cause change on an optical path behind the lens part 10b. Then, an optical path switching device 24 switching the optical path to a direction different from the optical path to a concave mirror 11 is provided on the optical path on the backside of the lens 10. A target 25 irradiated by a light source 18 for focusing a transmission side objective lens is provided at a position equivalent to the concave mirror 11 on another switched optical path.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission type confocal laser microscope for picking up a transmitted light image from a material.

[0002]

2. Description of the Related Art Generally, a confocal laser microscope scans a material surface with a laser beam spot that is narrowed down to about 1 micron, receives light and dark information at individual positions (points) with a photoelectric conversion sensor, and electrically converts the information. The bright and dark information is collected and observed on an enlarged screen of a monitor TV. This is because only individual positions are always illuminated, unnecessary and harmful light is not mixed, and light is received at a conjugate position with the material surface through a pinhole of a size similar to the light scanning light on the material surface,
There is a feature that defocused light and harmful light can be excluded.
Therefore, compared with the conventional optical microscope, high resolution and high contrast can be obtained even if the same objective lens is used.

There are two types of confocal laser microscopes, a reflective type that captures a reflected light image from a material and a transmissive type that captures a transmitted light image. A typical configuration of a conventional transmissive confocal laser microscope is shown in FIG. The general structure shown in is generally used. This laser microscope emits polarized laser light from a light source 1, thickens the light flux by an expander 2, transmits it through a polarizing beam splitter 3, and transmits it through a galvanometer mirrors 4 and 5, which are galvanometers with mirrors, in the horizontal direction (X), vertically. Direction (Y). Then, the relay lens 6 converges the field stop 7 at a position (corresponding to the image forming position of the objective lens) to a position corresponding to each scanning direction once,
The document 9 is scanned by the spot light through the irradiation side objective lens 8.

Then, the laser beam transmitted through the material 9 is passed through a transmission-side objective lens 10 equivalent to the irradiation-side objective lens 8 to form an image on the surface of the concave mirror 11. The concave mirror 11 has a spherical surface centered on the pupil position of the transmission-side objective lens 10 as a reflecting surface, and the light flux irradiated on the spherical surface is returned through exactly the same optical path. By providing the quarter-wave plate 12 that changes the polarization direction by 45 ° between the concave mirror 11 and the transmission-side objective lens 10, the reflected laser light returned to the polarization beam splitter 3 described above is Only the reflected light passing back and forth through the quarter-wave plate 12 is reflected and bent at a right angle, passes through the condenser lens 13, and the pinhole 1
Material information detection sensor 15 consisting of a light receiving element through
Then, photoelectric conversion is performed and an electric signal is sent to the memory.

In the figure, 16 is a binocular barrel, 17 is an optical path switching device when the binocular barrel is used, 18 is a light source for vertical epi-illumination, and 19 is a relay lens for the same light source.

[0006]

In use of this conventional transmission type confocal laser microscope, as shown in FIG. 3, a slide 21 is placed on a material table 20 and an illumination side objective lens 8 is attached to the surface of the material 9. Get burned. At this time, in order to focus the transmission-side objective lens 10 on the focal point, the slide 2
Since the position of the material surface differs depending on the thickness of No. 1, it is necessary to shift the transmission-side objective lens 10 by a slight amount (ΔL) each time. Usually when you exchange the slides,
There is a variation of about ± 0.3 m / m in the thickness of the glass portion.

Therefore, conventionally, as shown in FIG. 2, the optical path switching device 17 is switched to the optical microscope portion on the side of the binoculars barrel 16 and is illuminated by the light source 18 for vertical epi-illumination to focus the irradiation side objective lens 8. At the same time, a method is adopted in which the transmission side objective lens 10 is focused by dubbing it with the image of the reflected light from the concave mirror 11, and then the optical path switching device 17 is switched to the laser light side.

In addition to this, the transmission-side objective lens 10 is
It is adjusted in advance to the position when using a standard thickness preparation, and after focusing on the optical microscope part using the irradiation side objective lens 8, it is switched to laser light and the resolution is best while watching the image on the composite monitor. A method of finely adjusting the transmission-side objective lens 10 so that

In such a conventional apparatus, the focusing of the transmission-side objective lens is particularly troublesome, and the focusing accuracy is low, which makes it difficult to obtain high resolution.

In view of such conventional problems, the present invention makes it easy and accurate to focus the transmission-side objective lens.
The purpose of the invention is to provide a transmission type confocal laser microscope which can be operated in a stable state.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems and achieve the intended purpose, the gist of the present invention is to provide a laser spot light focused through an objective lens. Is provided at the position where the laser spot light transmitted to the back side of the material passes through a transmission-side objective lens equivalent to the irradiation-side objective lens and is imaged by the lens. In a transmission-type confocal laser microscope of a type in which the light is reflected by a concave mirror to make it go backwards and the retrograde light is received by a light-receiving element, a direction different from the optical path to the concave mirror is switched behind the transmission-side objective lens. An optical path switch is provided, and a target illuminated by a light source for focusing the transmission-side objective lens is provided at a position equivalent to the concave mirror in another optical path switched by the optical path switch. And a transmission-type confocal lens microscope (claim 1). Secondly, in the microscope, the transmission-side objective lens is composed of an objective lens unit that can move in the optical axis direction and a relay lens unit that is fixedly arranged. This is because the movement of the objective lens unit for focusing does not cause a change in the optical path after the relay lens unit (claim 2).

[0012]

In the transmission type confocal laser microscope of the present invention, the objective lens of the irradiation side is focused by moving the sample table (stage) while illuminating with the optical microscope part similar to the conventional one. When focusing on the transmission-side objective lens, the optical path from the objective lens to the concave mirror is switched to the target side, the light source for focusing is used to illuminate, and the transmission-side objective lens is adjusted while looking at the optical microscope to adjust the target. By focusing, both objective lenses can be made completely confocal (claim 1).

Further, according to the second aspect of the present invention, since the transmission-side objective lens is composed of the objective lens unit for moving and the relay lens unit of fixed arrangement, the focusing operation can be performed by moving only the objective lens unit. Therefore, the concave mirror after the relay lens, the optical path switching device, and the target can be built in a stable fixed block.

[0014]

EXAMPLE An example of the present invention will be described with reference to FIG. The same parts as those in the conventional example described above are designated by the same names and the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, the optical system from the light source 1 for emitting polarized laser light to the material 9 and the structure of the optical microscope portion from the light source 18 for vertical epi-illumination and the binocular barrel 17 to the material 9 are as follows. This is similar to the conventional example of FIG.

In the embodiment, the transmission-side objective lens 10 provided below the material table 20 is incorporated so that the relay lens portion 10b whose position is fixed and the relay lens portion 10b can be moved in the optical axis direction. Objective lens unit 10
and a. The objective lens unit 10a is equivalent to an infinite telescope barrel-length objective lens, and the objective lens unit 1
The objective lens unit 0b has the same characteristics as an imaging lens similar to a telescope objective lens.
Even if the distance between 0a and the relay lens portion 10b is changed, the optical performance after the relay lens portion 10b does not change.

An optical path switch 24 is provided behind the quarter-wave plate 12 in the optical path after the objective lens 10 on the transmission side. The optical path switch 24 comprises total reflection prisms 24a and 24b for switching the optical path in two directions at right angles. The one total reflection prism 24a bends the optical path at a right angle toward the concave mirror 11, and the other total reflection prism 24b bends the optical path at a right angle toward the focusing target 25 side.

The concave mirror 11 has a concave surface at the position where the laser beam reflected by the prism 24a is imaged by the transmission-side objective lens 10, and the pupil position of the objective lens 10 is the center of the concave surface.

Further, the target 25 is provided at the image forming position by the transmission-side objective lens like the reflecting surface of the concave mirror 11, and is constituted by a circular ring, for example. Then, the light is emitted from the light source 27 through the relay lens 26. The parts below the relay lens 26 are fixed in the fixed block 30. Also, the prism 2
4a and 24b may be shared by rotating one prism.

The laser microscope constructed in this way is
As shown in FIG. 1, a polarized laser beam is emitted from a light source 1 and is connected to a document 9 through an expander 2, a polarization beam splitter 3, Galvano mirrors 4,5, a relay lens 6, a visual field and an irradiation side objective lens 8 as in the conventional case. The surface of the document 9 is scanned with the spot light thus imaged. The transmitted light passes through the transmission-side objective lens 10, the optical path is bent by the reflection prism 24a, and is reflected by the concave mirror 11. When the reflected light passes through the same optical path in reverse and reaches the polarization beam splitter 3, only the reflected light is reflected and the optical path is bent at a right angle, passes through the condensing lens 13, and reaches the material information detection sensor 15 including a light receiving element. To detect.

Focusing of the irradiation-side objective lens 8 is performed by moving the material table 20 up and down on the objective lens 8 while viewing the material 9 using the binoculars barrel 17 and the light source 18 for vertical epi-illumination as shown in FIG. To focus.

For focusing of the transmission side objective lens 10, the optical path switch 24 is switched to the optical path on the side of the target 25, the light source 27 is turned on, and the binocular barrel 17 is used without using the light source 18.
With the naked eye, only the objective lens unit 10a is moved to focus on the target 25.

After focusing the both objective lenses 8 and 10 in this way, the upper optical path switch 17 is switched from the optical microscope portion to the laser light emitting side optical path, and the lower switch 24 is connected to the concave mirror 11 side. Then, the fluoroscopy with the laser beam described above is performed.

The focusing of the material on the irradiation side objective lens 8 is performed without using the light source 18 for vertical epi-illumination.
You may go while illuminating.

[0025]

As described above, according to the present invention, the focusing target is placed at the same position as the concave mirror in the rear optical path of the transmission side objective lens, and the focusing target is focused using the optical microscope section. By doing so, focusing of the transmission-side objective lens can be performed easily, quickly, and with high accuracy.

Further, the transmission-side objective lens is composed of the objective lens section and the relay lens section, and the movement of only the objective lens section does not cause a change in the optical path after the relay lens section. The concave mirror and the optical members reaching the target after that can be built in a fixed block that does not move in common. Therefore, a highly accurate transmissive confocal lens with the optical axes above and below the sample table perfectly aligned. A laser microscope can be easily obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a conventional example.

3A and 3B are diagrams comparing the movement of the objective lens unit of the conventional transmission type confocal laser scanning microscope.

[Explanation of symbols]

 1 Laser light 3 Polarizing beam splitter 4,5 Galvano mirror 6 Relay lens 8 Irradiation side objective lens 9 Material 10 Transmission side objective lens 10a Objective lens part 10b Relay lens part 11 Concave mirror 12 Wave plate 13 Condensing lens 14 Pinhole 15 Material information detection Sensor 17 Binocular barrel 18, 27 Light source 19 Relay lens 20 Data base 21 Preparation 24 Optical path switching device 24b, 24b Reflecting prism 25 Focusing target 26 Relay lens 30 Fixed block

Claims (2)

[Claims] 1. A laser spot light focused through an objective lens is irradiated from the front surface side of a material to be scanned, and transmitted light of the laser spot light to the back side of the material is a transmission side equivalent to the irradiation side objective lens. In a transmission-type confocal laser microscope of a type in which a light is passed through an objective lens, reflected by a concave mirror provided at a position where an image is formed by the lens and made to go backward, and the backward light is received by a light-receiving element, a transmission-side objective An optical path switch that switches the optical path to the concave mirror in a direction different from the optical path to the concave mirror is provided, and the same position as the concave mirror of another optical path switched by the optical path switch is illuminated by a light source for focusing the transmission-side objective lens. A transmission type confocal lens microscope, which is characterized by having a target. 2. The transmission-side objective lens is composed of an objective lens part that can move in the optical axis direction and a relay lens part that is fixedly arranged, and the movement of the objective lens part for focusing changes to the optical path after the relay lens part. The transmission type confocal laser microscope according to claim 1, wherein the transmission type confocal laser microscope is configured so as not to generate.