JP3039569B2 - Prism for total internal reflection measurement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prism for total reflection measurement suitable for a microscopic system for qualitative analysis by irradiating a minute area of a sample with light.

[0002]

2. Description of the Related Art In a total reflection measurement of a minute sample, light from a light source is narrowed down by a beam condenser and made incident on a prism on which the sample is adhered, and light absorbed by the sample is detected. However, since the light beam incident on the prism is diffused in the prism,
There is a problem that the measurement results for the entire sample cannot be obtained and analysis that specifies a minute area of the sample cannot be performed. In order to solve such a problem, a prism formed in a cross-shaped “<” shape is used, and a sample is brought into close contact with the prism for measurement. According to this method, it is possible to select a portion to be irradiated with infrared rays. On the other hand, in addition to the problem of requiring four times of total reflection before emission, the optical path length is inevitably increased and attenuation is caused. However, application to a sample having a high refractive index such as carbon is difficult.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to specify a measurement area of a sample, and to further specify an optical path length from incidence to emission. It is an object of the present invention to provide a novel prism for measuring total internal reflection, which makes it possible to reduce the attenuation by reducing the angle of incidence, and to make it possible to perform measurement at a plurality of large and small incident angles with the same prism.

[0004]

In order to solve such a problem, according to the present invention, an incident surface and an outgoing surface are formed so as to face each other, and the incident light from the incident surface is totally reflected. A first reflecting surface, a second reflecting surface facing the first reflecting surface and totally reflecting the light, and a second reflecting surface facing the second reflecting surface and adjacent to the first reflecting surface. A third reflecting surface for total reflection of the first, second,
Each of the three reflecting surfaces was used as a sample contact surface .

[0005]

The first and third reflecting surfaces receive light at a relatively large incident angle with respect to incident light, and the second reflecting surface receives light at a relatively small incident angle. When the sample is brought into close contact with and fixed to the third reflecting surface, measurement with a relatively large incident angle becomes possible. When the sample is brought into close contact with and fixed to the first reflecting surface, measurement with a relatively small incident angle becomes possible. In addition, by changing the position where the light from the light source is incident, part of the light does not reach the third reflecting surface and does not enter the detector, so that it is possible to perform measurement while selecting the sample area. Becomes

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows an embodiment of the present invention. In the drawing, reference numeral 1 denotes an M-shaped cross section made of an optical material capable of transmitting infrared rays, for example, KRS-5, ZnSe, or ZnS. In the infrared micro total reflection measurement prism, a first reflection surface 3 is formed at an angle at which total reflection is performed on infrared light incident on the incident surface 2. The reflecting surface 3 has a reflecting surface set at an angle of 30 degrees with respect to the incident surface 2 so that infrared light is incident at an angle of 60 degrees. On the side opposite to the first reflecting surface 3, the second angle is perpendicular to the incident surface 2 and is an angle for totally reflecting infrared rays from the first reflecting surface 3, for example, an incident angle of 45 degrees. On the side adjacent to the first reflecting surface 3 is formed a reflecting surface 4 at which the infrared light reflected by the second reflecting surface 4 is totally reflected with respect to the emitting surface 6, for example, an incident angle of 60 degrees. The third reflecting surface 5 is formed so as to form a corner.

In this embodiment, when measuring a sample requiring a relatively small incident angle, the sample S ₁ is brought into close contact with the first reflection surface 2 as shown in FIG. Fix it. In this state, the infrared light incident from the incident surface 2 is reflected by the first reflecting surface 3 and is incident on the second reflecting surface 4 at a relatively small incident angle of about 45 degrees. This allows the second
An infrared ray enters the sample S1 fixed at a relatively small angle on the reflecting surface 4 of the third reflecting surface 4 so as to absorb a component having a wavelength corresponding to the characteristics of the sample, and reflect other wavelength components to form a third reflecting surface. The light is reflected by 5 and exits from the exit surface 6. As a result, a total reflection measurement of a sample that requires the incidence of infrared light at a relatively small incident angle is performed.

On the other hand, when a measurement at a large incident angle is required, the sample S is brought into close contact with and fixed to the first reflecting surface 3 as shown in FIG. because they have a relatively large incident angle with respect to, will be incident at a large incident angle of 60 degrees to the sample S _2. Some of the wavelength components are absorbed according to the characteristics of the sample, and
Are reflected by the reflection surface 4 and the third reflection surface 5 and are emitted to the outside from the emission surface. As shown in FIG. 3 (c), by attaching and fixing the sample to the plurality of reflection surfaces 3 and 5, the sample can be subjected to multiple times of absorption and measurement with high sensitivity is possible.

By the way, when it is desired to measure a part of the sample attached to the reflecting surface, the position on the incident surface 2 where the light beam from the light source is incident is shifted as shown in FIG. Part of the infrared light reflected by the second reflecting surface 4 does not reach the third reflecting surface 5 and does not enter the detector. As a result, it is possible to perform measurement in which the region of the sample is specified.

In this embodiment, an example of measurement using infrared light has been described. However, it is apparent that the present invention can be applied to analysis using visible light by using a visible light transmitting material.

[0011]

As described above, in the present invention,
A first reflecting surface which is formed so that the incident surface and the emitting surface face each other and totally reflects the incident light from the incident surface; and a second reflecting surface which faces the first reflecting surface and totally reflects the light. When,
A third reflecting surface that faces the second reflecting surface and that is totally reflected on the exit surface on a side adjacent to the first reflecting surface; and any one of the first, second, and third reflecting surfaces is provided. Contact of sample
Having a surface, because the reflection surface of the first or third light is incident at a relatively large angle of incidence with respect to the incident light, and the second reflecting surface the light is incident at relatively small angles of incidence, First,
When the sample is brought into contact with the third reflecting surface, measurement at a relatively large incident angle is performed, and the sample is brought into contact with the second reflecting surface .
Thus, the measurement can be performed with a relatively small incident angle, and the incident angle to the sample can be changed by selecting one of the three surfaces on which the sample is mounted. Further, by changing the position where the light from the light source is incident, a part of the light does not reach the third reflecting surface and does not enter the detector, so that the measurement can be performed while selecting the sample area.

[Brief description of the drawings]

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

FIGS. 2A, 2B, and 2C are explanatory views showing states of use of the prism.

FIG. 3 is an explanatory diagram showing an operation when a specific region of a sample is selected and measured.

[Explanation of symbols]

Reference Signs List 1 prism main body 2 entrance surface 3 first reflection surface 4 second reflection surface 5 third reflection surface 6 exit surface S ₁ , S ₂ sample

Claims (1)

(57) [Claims] A first surface which is formed so that an incident surface and an outgoing surface face each other, and which is totally reflected with respect to incident light from the incident surface;
A second reflecting surface facing the first reflecting surface and totally reflecting, and a second reflecting surface facing the second reflecting surface and adjacent to the first reflecting surface with respect to the emission surface. A third reflecting surface that reflects the light, and the first, second, and third reflecting surfaces
All are prisms for measuring total internal reflection with a sample contact surface .