JPH063262A - Microscopic total reflection absorption spectrum measuring device - Google Patents

Abstract

PURPOSE:To visually confirm the analyzing point of a sample with a simple structure. CONSTITUTION:In a microscopic total reflection absorption spectrum measuring device, between an objective reflecting mirror and a sample, a visually confirming aperture 4 having a hole in the center part and an ATR measuring ring aperture 3 having an ATR prism 1 concentrically arranged below it are held in such a manner as to be rotatable with an axis parallel to the optical axis of objective reflection. The two apertures are switched between visual confirming time and ATR measuring time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a total reflection absorption spectrum measuring device using a reflection microscope system.

[0002]

2. Description of the Related Art Total reflection absorption spectrum measurement method (ATR)
Touch the sample surface with a transparent material having a higher refractive index than the sample (when infrared light is used, it should be transparent to infrared light), and from this high refractive index transparent material side, the boundary with the sample A method of measuring the absorption characteristics of a sample by injecting measurement light at an incident angle where total reflection occurs on the surface and detecting the absorption and extinction of the total reflected light by the sample. In the case of performing, a device using an infrared microspectroscopic device configured by a reflection optical system is used.

A conventional example will be described with reference to FIG. 1 showing an embodiment of the present invention. The objective mirror is a concave primary mirror 8B with a hole in the center.
And a convex sub-mirror 8A coaxial with the concave main mirror 8B. Monochromatic light emitted from a spectroscope (not shown) illuminates the optical axis of the objective mirror in the right half of the optical axis downward and parallel to the optical axis. The light is made incident on the system, and its light is reflected by the concave primary mirror 8B and the convex secondary mirror 8A and is condensed at the focal point 0 of the objective mirror optical system. The sample S is brought into contact with the lower surface of the hemispherical ATR prism 1 whose center is 0 point on the surface. In this case, the light condensed at the 0 point is
The light is not refracted by the ATR prism 1, is focused on the point 0 as it is, is totally reflected by the sample surface, goes up the left half of the optical axis of the objective optical system, and is detected.

Total reflection absorption spectrum measurement method (ATR)
Uses the total reflection, so that all the light is reflected by the bottom surface of the ATR prism as it is, and the sample cannot be visually observed. Therefore, as shown in FIG. 3 and FIG.
In an objective lens system using a hemispherical lens at the tip, the peripheral part of the uppermost objective lens 10 of the tip hemispherical lens is used as a convex secondary mirror 8A of the Cassegrain type catoptric objective optical system.
At the time of TR measurement, as shown in FIG.
The aperture 13 for measurement is arranged on the optical axis so that the measuring light is irradiated to the convex secondary mirror 8A, and at the time of visual measurement,
As shown in FIG. 4, a visual aperture 11 having a circular opening is arranged on the optical axis so that the measuring light is irradiated to the objective lens 10 so that the sample can be visually observed in the objective optical system. As shown in FIG. 5, the ATR prism 1 is made movable, and at the time of visual measurement, the ATR prism 1 is lifted in the optical axis direction by the lever 14 with the lens barrel as a fulcrum.
There is an example in which the R prism 1 is removed from the measurement optical path so that the measurement light does not pass through the ATR prism 1. However, as shown in FIG. 4, when a single lens is used for the objective optical system and the reflective optical system, it is difficult to manufacture a special lens and an aperture switching mechanism, and there is a problem that the cost is high. As shown in FIG. 5, if the ATR prism is made movable, the ATR prism moves in the optical axis direction. Therefore, when the ATR prism is pressed against the sample during the ATR measurement, the position of the ATR prism is not reproducible. There was a problem to say.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to make the analysis point of a sample visible by a simple mechanism.

[0006]

In a microscopic total reflection absorption spectrum measuring apparatus, an ATR is provided coaxially with a visual aperture having a hole in the center between an objective reflecting mirror and a sample, and is coaxial with the visual downward aperture.
A ring-shaped aperture for ATR measurement in which a prism is arranged is rotatably held on an axis parallel to the optical axis of the above-mentioned objective reflection, and two apertures are switched during visual observation and during ATR measurement.

[0007]

According to the present invention, two apertures, an aperture that transmits ambient light and an aperture that transmits paraxial light, are provided so as to be driven in conjunction with the ATR prism, and the movement direction of the prism is perpendicular to the optical axis. Then, for ATR measurement, an aperture that transmits ambient light is driven and arranged on the optical axis so that the light transmitted through the aperture is transmitted through the ATR prism and focused on the sample analysis point. Aperture that transmits only light is placed on the optical axis,
The light transmitted through the aperture is directly focused on the analysis point of the sample. Since the condensing point of the measurement light is the center of the hemispherical ATR prism 1 and the measurement light travels toward the center of the ATR prism 1, the optical path does not change. Does not need to be moved even when switching the measurement light during ATR measurement and visual measurement. As a result, since only paraxial light is used in visual observation, the aberration is very small and the image can be clearly observed. Since the sample was not moved during the ATR measurement and the visual measurement, the analysis point became more accurate. Further, as an optical system used, a combination of spherical mirrors has made it possible to obtain required performance.

[0008]

FIG. 1 shows an embodiment of the present invention. In the figure, 1 is an ATR prism, 2 is two notches 2A and 2B
2 is a switching plate having an aperture 3 and a viewing aperture 4 on the plate, as shown by the diagonal lines in FIG. 2 (the AA cross section in FIG. 1), and a Cassegeren type objective reflecting mirror 8 composed of a convex mirror 8A and a concave mirror 8B. It is rotatably held while being in sliding contact with the lower surface of the objective lens barrel K, which is rotatably supported by a shaft 5 standing on the lower surface of the objective lens barrel K in parallel with the optical axes of the (convex secondary mirror 8A and the concave primary mirror 8B). Is regulated by arranging the pins 6 and 7 standing on the lower surface of the lens barrel K at positions where the side surfaces of the cutouts 2A and 2B of the switching plate 2 come into contact with each other.
At the position (solid line) where the side surface of the notch 2A abuts on the ATR,
The center of the prism 1 and the optical axis of the Cassegrain mirror 8 coincide with each other, and at the position where the side surface of the notch 2B abuts the pin 7 (dashed line), the center of the visual aperture 4 and the Cassegrain mirror 8 The optical axes are aligned.

When performing measurement with this ATR objective mirror, first, the switching plate 2 is driven to align the center of the visual aperture 4 with the optical axis of the Cassegrain mirror 8. At this time, only paraxial rays that have passed through the visual aperture 4 are incident on the Cassegrain mirror 8, and it is possible to obtain a clear sample image with very little aberration and little distortion. In this state, the measurement point is searched while looking at the sample. Next, the switching plate 2 is driven again,
The center of the ATR prism 1 and the optical axis of the Cassegrain mirror 8 are aligned with each other, and the ATR measurement is performed. At this time, only the ambient light having the incident angle necessary for the ATR measurement is emitted from the Cassegrain mirror 8 and is totally reflected by the contact surface between the prism 1 and the sample. The reflected light is again cut off unnecessary light by the aperture 3, and only the necessary reflected light enters the Cassegrain mirror 8.

[0010]

According to the present invention, the prism movable ATR
In the objective reflection measurement device, the moving direction of the prism is perpendicular to the optical axis and the two apertures interlocking with the prism are provided, so that the sample can be visually observed and a good visual image can be obtained. The devices can now be made with spherical-only combinations that are easy to fabricate. In addition, since the structure is simple, the manufacturing cost is further reduced. In addition, the ATR objective reflection measurement device using the hemispherical prism is sensitive to the displacement of the position of the ATR prism in the optical axis direction, and even a slight displacement significantly deteriorates the performance. By making the prism moving direction perpendicular to the optical axis, even if the sample is pressed,
The TR prism does not move, and it is no longer necessary to make the machining accuracy too severe to obtain a highly accurate device.

[Brief description of drawings]

FIG. 1 is a side sectional view of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of driving an aperture in the above embodiment.

FIG. 3 is a side sectional view of a conventional example.

FIG. 4 is a side cross-sectional view of the above conventional example in a visual state.

FIG. 5 is a side sectional view of another conventional example.

[Explanation of symbols]

 K Objective reflecting mirror barrel 1 ATR prism 2 Switching plate 3 Aperture 4 Visual aperture 5 Axis 6 pin 7 pin 8 Objective reflecting mirror 8A Convex mirror 8B Concave mirror

Claims (1)

[Claims] 1. A total reflection absorption spectrum measuring apparatus having a reflective objective optical system composed of a concave primary mirror and a secondary mirror, and comprising a hemispherical ATR prism centered on a focal point of the optical system.
A switching plate is pivotally attached to the lower end surface of the lens barrel of the reflective objective optical system so as to be rotatable about an axis parallel to the optical axis of the optical system. When the switching plate is rotated, an image is formed on the switching plate. Two types of apertures are provided centered on the passage of the optical axis of the reflective objective optical system, one of which is a circular aperture that blocks the peripheral light flux of the reflective objective optical system and allows the central light flux to pass therethrough, and the other. Is a ring-shaped aperture for passing a peripheral light beam of the reflective objective optical system and blocking a central light beam, and an ATR prism is fixed under the latter aperture by the switching plate. .