JPH04301744A - Prism for micro-total refection measurement - Google Patents

Abstract

PURPOSE:To enable micro total-reflection measurement with the two kinds, large and small, of incident angles by the use of the same prism without attenuation. CONSTITUTION:A device is provided with a first reflecting surface 3 by which incident light is totally reflected, a second reflecting surface 4 which faced to the first reflecting surface 3 while incident light is totally reflected, and with a third reflecting surface 5 which is faced to the second reflecting surface 4 while light is totally reflected to a light emission surface, and the device is so designed that specimens can be adhered and fixed onto the second reflecting surface 4 and the first reflecting surface 3. Since incident light comes in the first and the third reflecting surfaces 3 and 5 at a comparatively large incident angle, and since light comes in the second reflecting surface 4 at a comparatively small incident angle, if the specimens are adhered and fixed onto the first and the third reflecting surfaces 3 and 5, measurement by the comparatively large incident angle can thereby be made, and if the specimen is adhered and fixed onto the second reflecting surface 4, measurement by the comparatively small incident angle can thereby be made. Furthermore, when a position from which light is radiated to the plane of incidence 2, is changed, a part of light does not come in the third reflecting surface 5 while no light comes in a detector, measurement can thereby be made while the range of the specimen is being selected.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prism for measuring total reflection, which is suitable for a microscopic method in which qualitative analysis is performed by irradiating light onto a minute area of a sample.

0002

[Prior Art] In total reflection measurement for a minute sample, light from a light source is focused by a beam condenser and incident on a prism with the sample in close contact with it, and the light absorbed by the sample is detected. However, since the light beam incident on the prism is diffused within the prism,
There is a problem in that the measurement results are for the entire sample, making it impossible to analyze a specific micro region of the sample. To solve this problem, a prism with a dogleg-shaped cross section is used, and the sample is brought into close contact with the prism for measurement. According to this, while it is possible to select the location where infrared rays are irradiated, there is the problem that the optical path length inevitably increases because it requires four total reflections before it is emitted, causing attenuation. However, it was difficult to apply this method to samples with a high refractive index, such as those containing carbon.

0003

[Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances, and its purpose is to make it possible to specify the measurement area of a sample, and to reduce the optical path length from input to output. It is an object of the present invention to provide a new prism for microscopic total internal reflection measurement, which can reduce attenuation by reducing the angle of incidence, and further enables measurement with a plurality of large and small types of incident angles using the same prism.

0004

[Means for Solving the Problems] In order to solve such problems, the present invention includes a first reflective surface that totally reflects incident light, and a surface that faces the first reflective surface and that completely reflects the incident light. a second reflecting surface that performs total reflection, and a third reflecting surface that faces the second reflecting surface and performs total reflection on the output surface, and a sample is placed on at least the second, first, or third reflecting surface. The structure is designed to allow for close contact and fixation.

[0005]

[Operation] Since light enters the first and third reflecting surfaces at a relatively large angle of incidence relative to the incident light, and light enters the second reflecting surface at a relatively small angle of incidence, the first and third reflecting surfaces When the sample is closely attached and fixed to the third reflecting surface, measurement can be performed at a relatively large angle of incidence, and when the sample is closely attached and fixed to the first reflecting surface, measurement can be carried out at a relatively small angle of incidence. In addition, by changing the incident position of the light from the light source, some of the light no longer reaches the third reflective surface and enters the detector, making it possible to select and measure areas of the sample. becomes.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be explained below based on illustrated embodiments. FIG. 1 shows an embodiment of the present invention, in which reference numeral 1 is made of an optical material that can transmit infrared rays, such as KRS-5, ZnSe, or ZnS, and has an "M"-shaped cross section. This is a prism for infrared microscopic total reflection measurement, and a first reflecting surface 3 is formed at an angle that causes total reflection of infrared rays incident from an incident surface 2. The reflective surface 3 is set to form an angle of 30 degrees with respect to the incident surface 2, so that the infrared light is incident at an angle of 60 degrees. On the side facing the first reflective surface 3, there is a second surface at a right angle to the incident surface 2 and at an angle that totally reflects the infrared rays from the first reflective surface 3, for example, at an incident angle of 45 degrees. A reflective surface 4 is formed, and further, on the side adjacent to the first reflective surface 3, there is an incident angle, for example, 60 degrees, for total reflection of the infrared light reflected by the second reflective surface 4 toward the output surface 6. A third reflective surface 5 is formed to form a corner.

In this embodiment, when measuring a sample that requires a relatively small angle of incidence, the sample S1 is fixed in close contact with the first reflective surface 2 as shown in FIG. do. In this state, the infrared light that enters from the incident surface 2 is reflected by the first reflective surface 3 and enters the second reflective surface 4 at a relatively small incident angle of about 45 degrees. This allows the second
Infrared rays are incident at a relatively small incident angle on the sample S1, which is closely fixed to the reflective surface 4 of 5 and exits from the exit surface 6. As a result, total reflection measurement of the sample, which requires the incidence of infrared rays at a relatively small angle of incidence, can be performed.

On the other hand, when measurement at a large angle of incidence is required, the sample S is tightly attached and fixed to the first reflective surface 3 as shown in (b) of FIG. Since it has a relatively large incident angle with respect to the sample S2, it will be incident on the sample S2 at a large incident angle of 60 degrees. Depending on the characteristics of the sample, some of the wavelength components are absorbed, and the remaining components are absorbed by the second wavelength component.
The light is reflected by the reflective surface 4 and the third reflective surface 5, and is emitted to the outside from the output surface. By the way, as shown in FIG. 3C, by closely contacting and fixing the sample to a plurality of reflective surfaces 3 and 5, the sample can absorb multiple times, making it possible to perform measurements with high sensitivity.

By the way, when it is desired to measure a part of the sample attached to the reflective surface, as shown in FIG. A part of the infrared rays reflected by the second reflecting surface 4 no longer reaches the third reflecting surface 5 and is no longer incident on the detector. This makes it possible to measure a specific region of the sample.

Although this embodiment has been explained by taking an example of measurement using infrared rays, it is obvious that it can also be applied to analysis using visible light by constructing it from a material that transmits visible light.

[0011]

[Effects of the Invention] As explained above, in the present invention,
A first reflective surface that totally reflects the incident light; a second reflective surface that faces the first reflective surface and that totally reflects the incident light; and a second reflective surface that faces the second reflective surface and totally reflects the incident light. Since the sample is configured to be able to be closely attached and fixed to at least the second, first, or third reflecting surface, the first or third reflecting surface is not exposed to the incident light. On the other hand, light is incident on the second reflecting surface at a relatively large incident angle, and light is incident on the second reflecting surface at a relatively small incident angle.
When the sample is closely attached and fixed to the second reflecting surface, measurements can be made at a relatively large angle of incidence, and when the sample is attached and fixed to the second reflecting surface, measurements can be made at a relatively small angle of incidence.
The angle of incidence on the sample can be changed simply by changing the surface on which the sample is mounted. Additionally, by changing the incident position of the light from the light source, a portion of the light no longer reaches the third reflective surface and enters the detector, making it possible to select and measure areas of the sample. .

[Brief explanation of drawings]

FIG. 1 is a side view showing one embodiment of the present invention.

FIG. 2A, FIG. 2B, and FIG. 2C are explanatory diagrams each showing how the prism is used.

FIG. 3 is an explanatory diagram showing the operation when selecting and measuring a specific region of a sample.

[Explanation of symbols]

1 Prism body 2　Incidence surface 3 First reflective surface 4 Second reflective surface 5 Third reflective surface 6 Output surface S1, S2 samples

Claims (1)

[Claims] Claim 1: a first reflective surface that totally reflects incident light; a second reflective surface that faces the first reflective surface and that performs total internal reflection; and a second reflective surface that faces the second reflective surface and that 1. A prism for microscopic total internal reflection measurement, comprising a third reflecting surface that performs total reflection on an output surface, and configured such that a sample can be brought into close contact with and fixed to at least the second, first, or third reflecting surface.