JP3048418B2 - Infrared total reflection absorption measuring device and crystal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared total reflection absorption measuring apparatus and a crystal which can be used for local analysis, line analysis, and surface analysis of a sample surface using infrared rays.

[0002]

[Prior art]

(Background) A crystalline material having a high relative refractive index (the refractive index of the substance divided by the refractive index of air; hereinafter simply referred to as “refractive index”) is brought into close contact with a sample to be measured having a low refractive index. When infrared light is incident on the interface from the crystal side at an angle greater than the critical angle, the infrared light enters the sample side at a certain depth at the interface and is totally reflected, so if the sample has the property of absorbing infrared light The intensity of the total reflected light decreases according to the intensity of the absorption. By spectrally detecting and detecting this total reflection light, an infrared total reflection spectrum unique to the sample is observed. The infrared total reflection absorption measuring device obtains information on the chemical composition of a few μm layer from the surface of the sample by analyzing such a spectrum, and obtains a polymer material (rubber, coating film, etc.) having a relatively low refractive index. , Plastic, etc.) are widely used for surface analysis.

(Prior Art) A typical example of a conventional infrared total reflection absorption measuring apparatus is a multiple total reflection type infrared total reflection absorption measuring apparatus shown in FIG. In this apparatus, infrared light is condensed by a condenser mirror 1 on an incident surface 3 of a crystal 2 for total reflection and made incident, and the total reflection of the crystal 2 is performed in the process of multiple total reflection inside the crystal 2. A plurality of infrared total reflections are performed at the interface between the sample 5 to be measured and the crystal body 2 adhered to the reflection surface 4 to improve the surface analysis sensitivity.
Is transmitted to a detector (not shown) via the objective mirror 7.

On the other hand, in a conventional infrared total reflection absorption measuring apparatus, as shown in FIGS. 16 (1) to 16 (3), a total reflection crystal having a parallelogram or trapezoidal cross section is used.

[0005]

[Problems to be solved by the invention]

(Problems of the prior art) By the way, the demand for micro-analysis of a sample in recent years is severe, and for example, a surface analysis of a minute area on the order of 10 μm on a sample surface has been required.

[0006] However, in the above-mentioned multiple total reflection type infrared total reflection absorption measuring apparatus, the infrared light condensed on the incident surface of the crystal diverges inside the crystal, and the infrared light is efficiently reflected on the sample surface. from such that hardly is converged manner, since it is difficult enhanced light quantity utilization in a micro area to be measured, 100 [mu] m
Analysis of small samples of the order is the limit. Then, even provisionally selected infrared light from a sample surface area of the particular 10μm order by a slit, an effective infrared total reflection spectra lack of infrared light intensity of the specimen surface area based on a lack of light quantity utilization Cannot be obtained, and the analysis of the sample surface area cannot be performed.

Next, in accordance with the above-mentioned requirement of micro analysis,
For example, there is a demand to perform a line analysis divided into minute areas of the order of 10 μm on a band-shaped sample surface area. However, the conventional infrared total reflection absorption measurement apparatus has such a problem in terms of analysis capability as described above. In addition to the inability to meet the requirements, the multiple total reflection method originally obtains an average analysis value of multiple sample surface areas corresponding to multiple infrared total reflections. It is incompatible with the request.

Further, there is a demand for a surface analysis in which a sample surface area of a fixed area is divided into small areas of the order of 10 μm. For the same reason as in the case of line analysis, a conventional infrared total reflection absorption measuring apparatus is used. Cannot respond to such demands.

In the conventional multiple total reflection type infrared total reflection absorption measuring apparatus, the focus of the objective mirror is usually set to the exit surface of the crystal in order to obtain the strongest infrared information. Therefore, point analysis, line analysis, and surface analysis cannot be performed while visually observing a specific measurement point using an objective mirror, and even if a visual observation function using an objective mirror is provided, it has no meaning.

In the conventional total reflection crystal, FIG.
As shown by a broken line therein, a shift occurs in the optical axis between the incident light and the outgoing light. Therefore, since the converging mirror 1 and the objective mirror 7 cannot be arranged on the same axis (see FIG. 17), a condensing optical system in which the condensing mirror and the objective mirror, which are conventionally frequently used, are arranged on the same axis is provided. There is the inconvenience that an infrared microscope cannot be used.

(First problem) A first problem of the present invention is to provide an infrared total reflection absorption measuring apparatus capable of analyzing the surface of a minute area of the order of 10 μm under visual observation with an objective mirror. is there.

(Second Problem) A second problem of the present invention is as follows.
10 μm on the sample surface under visual observation with an objective mirror
An object of the present invention is to provide an infrared total reflection absorption measuring apparatus that can easily perform line analysis divided for each minute area of order.

(Third Problem) A third problem of the present invention is as follows.
10 μm on the sample surface under visual observation with an objective mirror
An object of the present invention is to provide an infrared total reflection absorption measuring device capable of performing a surface analysis divided for each minute area of an order.

(Fourth Problem) A fourth problem of the present invention is as follows.
For the total reflection such that an infrared microscope having a condensing optical system in which a condensing mirror and an objective mirror, which are widely used in the past, are arranged on the same axis can be easily used to constitute an infrared total reflection absorption measuring apparatus. It is to provide a crystal.

(Fifth Problem) The fifth problem of the present invention is as follows.
By applying the crystal to the infrared total reflection absorption measurement apparatus capable of analyzing the micro area, the first to
An object of the present invention is to provide an infrared total reflection absorption measuring device that can respond to all the fourth problems.

[0016]

[Means for Solving the Problems]

(Focusing point) As a result of experimentally and rigorously determining the sensitivity of the latest infrared light detector and the intensity of infrared light that can be converged on the sample surface, the present inventor found that red light was measured in infrared total reflection absorption measurement. By effectively increasing the utilization rate of external light, it is possible to design an infrared total reflection absorption measurement apparatus that effectively performs surface analysis of a small area of the order of 10 μm by only one total reflection. It has been found that the above disadvantages based on the reflection method, such as the inability to utilize the visual observation function using an objective mirror, can be solved.

(Means for Solving the First Problem) The configuration of the first invention of the present application (the invention described in claim 1) for solving the above first problem has the following elements (a) to (e): And the optical path length is set such that the focal point of the infrared light is located on the total reflection surface of the crystal of (c), and the optical axis of the condenser mirror and the objective mirror is , Are arranged on the same axis. (B) placed on the collector mirror for focusing infrared light (b) a sample holder for holding the measurement specimen (c) the sample holding portion, the infrared light from the focusing mirror is incident A crystal body having an incident surface, a total reflection surface for bringing the sample to be measured into contact with the sample to perform total reflection measurement of infrared light only once, and an emission surface from which infrared light is finally emitted. A) an objective mirror which is arranged to face the emission surface of the crystal and is capable of focusing on the measurement point of the sample to be measured brought into contact with the total reflection surface; e) selecting infrared light emitted from the emission surface. Slit

(Means for Solving the Second Problem) The structure of the second invention of the present application (the invention of claim 2) for solving the above second problem is the same as that of the first invention, except that The sample holding unit of (b) is a columnar body whose input surface, total reflection surface and output surface are formed as planes parallel to the column axis, and are provided in a direction perpendicular to the output optical axis. Is an infrared total reflection absorption measurement apparatus having a drive mechanism capable of moving the crystal in parallel along at least the column axis direction of the crystal.

(Means for Solving the Third Problem) The structure of the third invention of the present application (the invention according to claim 3) for solving the above third problem is the same as that of the first invention, except that The body is a columnar body in which the incident surface, the total reflection surface, and the emission surface are formed as planes parallel to the column axis, and is provided so as to be oriented in a direction perpendicular to the emission optical axis. It has a drive mechanism that can arbitrarily translate the crystal in a three-dimensional direction, and this drive mechanism predicts a deviation from the focal point of a measurement point when the crystal is translated in a direction different from the column axis direction. A control system comprising: means for calculating; then means for calculating a correction movement amount along the emission optical axis required to eliminate the deviation based on the predicted value; and control means for driving the drive mechanism in accordance with the results of these calculations. Has infrared total reflection absorption A constant apparatus.

(Means for Solving the Fourth Problem) The structure of the fourth invention (the invention described in claim 4) for solving the fourth problem is that a sample to be measured is provided in an infrared total reflection absorption measuring apparatus. A crystal placed on a sample holding unit for holding the sample, the incident surface on which the infrared light from the condenser mirror is incident, and the sample to be measured are brought into contact with each other to perform a total reflection measurement of the infrared light. A total reflection surface for performing the operation, at least three reflection surfaces (including the total reflection surface) for changing the direction of incident light, and an emission surface from which infrared light is finally emitted; Is a crystal in which the mutual angles of the respective reflection surfaces are configured so that the optical axis of the light beam and the optical axis of the emitted light coincide with each other.

(Means for Solving the Fifth Problem) The structure of the fifth invention (the invention described in claim 5) for solving the fifth problem is one of the first invention to the third invention. Among the infrared total reflection absorption measurement apparatus described in, the infrared total reflection absorption measurement apparatus in which the converging mirror and the objective mirror are arranged on the same axis, the crystal used in the apparatus, In the crystal according to the fourth aspect of the present invention, a columnar body whose incident surface, total reflection surface, and emission surface are formed as planes parallel to the column axis, and which is provided so as to be directed in a direction perpendicular to the emission optical axis. It is a reflection absorption measurement device.

[0022]

[Action]

(Operation of the First Invention) In the first invention, infrared light having passed through the condenser mirror is incident on the crystal from the incident surface of the crystal, and the infrared light is collected on the total reflection surface in contact with the sample to be measured. Light and totally reflected once. Thereafter, of the infrared light emitted from the emission surface, only the emission light that is totally reflected from the measurement point on the sample surface is selected and taken out by the slit, thereby measuring the infrared total reflection absorption spectrum of the sample surface to be measured. I do.
Further, in the method of the present invention, it is reasonable to keep the focus of the objective mirror at the point where the strongest infrared information can be obtained, that is, at the measurement point on the sample surface. Can be performed in parallel.

Even if only the outgoing light that is totally reflected from the measuring point of the order of 10 μm on the sample surface out of the infrared light emitted from the outgoing surface is selected and extracted by the slit, multiple total reflection on the sample surface is not performed. Because the divergence of infrared light inside the crystal body is small, and the infrared light is collected on the total reflection surface, etc., the utilization rate of light per unit area of the sample surface is high,
Even at the current level of the infrared light detector, the measurement of the infrared total reflection absorption spectrum can be effectively performed.

(Function of the Second Invention) In the second invention, by moving the crystal in contact with the sample to be measured in parallel in the column axis direction, an extremely small area of the order of 10 μm is formed along the moving direction. A separate line analysis is performed. At this time, since the optical path length of the infrared light inside the crystal and the relative position of the total reflection surface of the crystal do not change at all, the focal point of the infrared light is always located on the total reflection surface of the crystal. . That is,
Since the total reflection condition is constant even when the crystal is moved in parallel in the column axis direction, accurate line analysis is achieved. In the line analysis, observation of the sample surface with an objective mirror may be performed in parallel.

(Operation of the Third Invention) In the third invention, when the crystal body in contact with the sample to be measured is moved in parallel in the column axis direction, the same operation as in the second invention occurs.
Also, when the parallel movement of the crystal includes the amount of movement in the direction perpendicular to the column axis, a focus shift from the measurement point occurs according to the numerical aperture of the objective mirror and the focusing mirror and the refractive index of the crystal. The control system instructed with the expected movement value predicts and calculates this deviation, and then calculates the corrected movement amount along the emission optical axis necessary for eliminating the deviation, and the focal point does not deviate from the measurement point according to the calculation result. Drive mechanism to move the crystal as described above. Since the above-described correction movement is along the emission optical axis, there is no displacement of the measurement point. This enables automatic surface analysis of the sample surface. In addition, since the focal point of the objective mirror always coincides with the measurement point in the surface analysis, observation of the sample surface by the objective mirror may be performed in parallel.

(Operation of the Fourth Invention) In the fourth invention, the infrared incident light is irradiated on at least three reflection surfaces (total reflection surfaces with which the sample to be measured is brought into contact) formed with a specific angle relationship. ), And is emitted coaxially with the incident light by being reflected at least three times.

(Operation of the fifth invention) In the fifth invention,
Since all the features of the first to fourth inventions are provided, all the functions of the first to fourth inventions are performed.

[0028]

【The invention's effect】

(Effect of the First Invention) According to the first invention, the surface analysis of a minute area of the order of 10 μm on the sample surface can be performed under visual observation with an objective mirror.

(Effects of the Second Invention) According to the second invention, the crystal in contact with the sample to be measured is moved along the axis of the column by a simple operation to move the crystal on the sample surface.
Line analysis divided into micro areas on the order of μm can be performed under visual observation with an objective mirror.

(Effects of the Third Invention) According to the third invention, the sample to be measured is divided into small areas of the order of 10 μm on the sample surface without deviation of the focal point of the objective mirror from the measurement point on the sample surface. Line analysis and surface analysis can be performed under visual observation with an objective mirror.

(Effect of the Fourth Invention) Since the coincidence of the optical axes of the incident light and the outgoing light can be ensured only by using the crystal according to the fourth invention, the converging mirror and the objective mirror which have been frequently used in the prior art can be used. Can be used as it is to use an infrared microscope having a converging optical system in which the infrared ray is arranged on the same axis, to configure an infrared total reflection absorption measuring apparatus.

(Effect of Fifth Invention) According to the fifth invention, all the effects of the first to fourth inventions can be obtained simultaneously.

[0033]

[Embodiment 1]

(Structure of Embodiment 1) This embodiment is one embodiment of the fourth invention. FIGS. 1A to 1D show examples of columnar crystals configured so that the optical axis of incident light and the optical axis of outgoing light coincide with each other. FIG. 1C shows that the shape viewed from the column axis direction is 5.
As shown in the figure, an incident surface, three reflecting surfaces including a total reflecting surface to which the sample to be measured is brought into contact, and an emitting surface, as shown in FIG. And
A light reflection processing film 11 is formed on one of the reflection surfaces. Next, FIG. 1 (d) shows a hexagonal prism having a shape viewed from the column axis direction, and the incident surface and the sample to be measured are indicated by broken arrows in FIG. It has four reflecting surfaces including a total reflecting surface to be brought into contact, and an emitting surface. The numbers in FIGS. 1C and 1D indicate the ratio of the length of each side of the crystal. FIG. 1 (c) and FIG.
The incident surface, the reflecting surface and the emitting surface in (d) are all formed as planes parallel to the column axis. In these crystals, the incident light is reflected three times and four times inside the crystal as shown by the broken optical path, and is emitted on the same optical axis as the incident light. In FIG. 1 (c) or FIG. 1 (d), which one of the reflecting surfaces is used as the total reflecting surface for contacting the sample depends on the relationship with the overall configuration of the infrared ray total reflection absorption measuring device and the like. And can be arbitrarily selected.

Further, a general formula is shown in the case where a crystal having an arbitrary shape whose number of reflections is four in the optical system is arranged in an optical system in which incident light and outgoing light are coaxial. FIG.
(A) shows an optical path when the incident surface 8 and the outgoing surface 13 of the crystal are parallel to each other and arranged perpendicular to the optical axis of the incident light. Here, assuming that the respective reflecting surfaces inside the crystal body are reflecting surfaces 9, 10, 11 and 12 from the incident surface side, and the angles between the incident light and the reflected light on the respective reflecting surfaces are α, β, γ and δ. The shape of the crystal is composed of four reflecting surfaces and an input and output surface inside the crystal satisfying the following formula.

Α + δ = β + γ (1) However, at least one of α, β, γ and δ is at least twice the critical angle and satisfies the condition of total reflection. On the other hand, as shown in FIG.
3 are not parallel to each other and have an arbitrary inclination with respect to the optical axis of the incident light, the left side of the equation (1) is corrected by the terms of the incident angle and the refraction angle at the entrance / exit surfaces.
It can be expressed as in equation (2). That is, the shape of the crystal in this case is determined by the four reflection surfaces inside the crystal satisfying the expression (2), provided that the input / output angles at the input / output surfaces and the refractive index of the crystal are defined.

(Α ± θ _I ) + (δ ± θ _E ) = β + γ (2) where θ _I = θ _Ii −θ _Ir θ _E = θ _Er −θ _Ei θ _Ii : incidence surface 8 Θ _Ir : refraction angle from the incident surface 8 θ _Er : refraction angle from the exit surface 13 θ _Ei : incident angle on the exit surface 13.

In equation (2), the terms in parentheses on the left side are:
When each theta _a and theta _b optical axis and a third angle between the optical axis and the incident and emitting axis of the reflected light of the first reflected light, when _{α> θ a, (α-} θ I) α <θ a when a case of _{(α + θ I) δ>} θ b, when the _{(δ-θ E) δ <} θ b, (δ + θ E).

As described above, taking the case where the light is reflected four times inside the crystal as an example, the incident light that has entered the inside of the crystal is 360
Although the conditions for emitting light in the direction of ° have been theoretically described, the same can be obtained for the case of three or more reflections. The incident surface and the reflective surface of the above crystal are
In order to suppress the reflection loss of light on each surface, it is desirable that the surfaces are perpendicular to the optical axes of the incident light and the reflected light. Further, the shape of such a crystal is desirably a simple structure such that total reflection conditions can be easily obtained inside the crystal and the crystal can be easily manufactured. It is desirable that the angle formed between the one reflecting surface and the exit surface and the final reflecting surface is 30 ° to 60 °, and that the number of reflecting surfaces inside the crystal be as small as possible.

(Operation of Embodiment 1) Next, the operation in the case where the light is reflected four times inside the crystal body and the final reflection surface is the total reflection surface will be described with reference to FIG. The infrared light incident on the inside of the crystal through the reflector is first reflected on the first reflection surface at a reflection angle α / 2, the reflected light propagates inside the crystal body, and further reflected on the second reflection surface at a reflection angle β / 2. reflect. Next, this infrared light is reflected by the third reflection surface at a reflection angle γ.
/ 2, and reaches the final reflection surface. The infrared light incident on the final reflection surface satisfies the condition of total reflection at an incident angle of 30 to 60 °, and is totally reflected at a reflection angle δ / 2. The infrared light totally reflected has the optical axis coincident with the incident light, and is emitted in a direction of 360 ° with respect to the incident light having entered the inside of the crystal. At this time, by bringing the measured surface of the sample into close contact with the total reflection surface of the final reflection surface, infrared total reflection absorption measurement can be performed.

(Effect of Embodiment 1) By using the crystal of the present embodiment, infrared light incident on the crystal can be emitted on the same axis as its optical axis. For this reason, an infrared total reflection absorption measuring apparatus can be configured by using, as it is, an infrared microscope having a condensing optical system in which a condensing mirror and an objective mirror, which are conventionally frequently used, are arranged on the same axis.

[Embodiment 2] (Structure of Embodiment 2) This embodiment is one embodiment in which the crystal of the fourth invention is applied to the first invention. FIGS. 2, 3 (a) and 3 (b) show examples of the infrared total reflection absorption measuring device constituted by using the crystal of the first embodiment.
Shown in The crystal body 14 is the one shown in FIG. 1D described above and is a hexagonal columnar body having a cross-sectional shape bent in a substantially “<” shape. The crystal body 14 has an entrance surface 8, a first reflection surface 9, a final reflection surface 12, and an exit surface 13, and the final reflection surface 12 has a sample holder 16 to be measured by a sample holder 15.
Is abutted.

The crystal body 14 is placed in a holder (not shown).
Fig. 3 (a)
It is shown in FIG. The crystal 14 attached to the holder is placed on a sample stage 17 (three-dimensional stage) constituting a sample holding unit, and an objective mirror 18 is provided on the upper part thereof, and a condensing mirror 19 is provided on the lower part thereof on the same axis. Have been. Objective mirror 18
Are focused on the final reflecting surface 12 and the crystal 1
The length of each side of 4 is adjusted so that the focal point of the condenser mirror coincides with the focal point of the objective mirror when attached to the infrared microscope. The sample stage 17 may be a fixed type, a movable type along the column axis direction (depth direction in FIG. 3 (a) or FIG. 3 (b)) of the arranged crystal, or an arbitrary three-dimensional direction. It may be movable. The infrared microscope is provided with a movable slit 20 so that only light reflected from a measured portion on the sample surface can be sent to a detector attached to the infrared microscope. Although not shown, the condenser mirror 19 can be arbitrarily irradiated with either infrared light or visible light via a movable reflecting mirror for switching.

(Effect of Embodiment 2) Any one of the total reflection surfaces of the crystal 14 (the final reflection surface 12 in this embodiment)
The sample 16 is brought into close contact with the sample, and the incident surface 8 is irradiated with infrared light from a condenser mirror 19. The incident light is reflected inside the crystal body 14 as shown in FIG. 2 and is condensed on the final reflection surface 12, enters the sample side to a certain depth, and is totally reflected. The total reflection light is sorted by a slit to obtain 10
An infrared total reflection absorption spectrum of a micro area on the order of μm is measured. By analyzing this spectrum, a minute area on the sample surface is analyzed.

In this embodiment, the sample table 17 is driven to move the crystal 14 in parallel, so that the infrared total reflection absorption spectrum of the sample surface is continuously measured, and line analysis and surface analysis on the sample surface are performed. You can also. When the line analysis is performed along the column axis direction of the crystal 14, the focal point of the objective 18 does not deviate from the measurement point. When performing line analysis or surface analysis in other directions, the focus of the objective mirror 18 deviates from the measurement point. Therefore, the movement of the sample stage 17 is appropriately adjusted to correct the deviation. In addition, with the adjustment movement, the focus of the objective mirror 18 is adjusted if necessary. If the observation of the sample surface by the objective mirror 18 is performed in parallel, the movement of the sample 16 for line analysis or surface analysis can be performed more quickly and accurately.
In this observation, a clearer image is observed as the adhesion of the sample 16 to the crystal 14 is better and the absorption coefficient of the sample 16 for visible light is higher.

(Effect of Second Embodiment) The infrared total reflection absorption spectrum of a small area of the order of 10 μm in the sample to be measured can be measured. The information obtained by the infrared total reflection absorption measurement device is
This is an infrared absorption spectrum based on the bending vibration, whereby a chemical change of a chemical composition or a component of a surface layer can be specified, and a temporal change or deterioration of a surface can be analyzed. In addition, since the difference in chemical composition and chemical change of each component on the sample surface can be analyzed by line analysis and surface analysis, the difference in the way of time-dependent change and deterioration or the way of influence by the part can be analyzed. It can be applied as an effective means of developing and improving products and materials.

[0046][Reference Example 1] (Configuration of Reference Example 1)  BookReference exampleIn the first invention, the converging mirror and the objective mirror
Of two or three cases where it is not necessary to arrange on the same axis
For aspects. In these descriptions, the objective 18, the collection
The optical mirror 19 and the sample stage 17 are in the case of the second embodiment.
Therefore, detailed description is omitted.

In the embodiment shown in FIGS. 4A to 4C, the columnar crystal 14 having a parallelogram cross section is shown.
a, 14b, and 14c are used, respectively. Each crystal 14
a, 14b and 14c are one incident surface 8a and 8 respectively.
b, 8c, one first reflecting surface 10a, 10b, 10c,
It has one final reflection surface 12a, 12b, 12c and one emission surface 13a, 13b, 13c. The focusing mirror and the objective mirror schematically shown in the figure are respectively on the optical path indicated by the arrow,
That is, they are arranged on axes that are parallel but offset from each other. The sample 16 to be measured is placed on the final reflection surface 12 as shown in FIG.
In addition to the case of contact with the first reflective surfaces a, 12b, and 12c, the measurement can be performed by contacting the first reflective surfaces 10a, 10b, and 10c. The acute angle among the internal angles in the parallelogram of the cross-sectional shape of each crystal body 14a, 14b, 14c
a, 10b, 10c, 12a, 12b, and 12c, which correspond to the incident angle and the reflection angle, and satisfying the total reflection condition, from 30 ° shown in FIG. 4A to 60 ° shown in FIG.
Any angle can be used in the range of FIG.
Of about 45 ° shown in FIG.

In the reference example shown in FIG. 5A, a columnar crystal 14d having a right-angled triangular cross section is used.
The crystal 14d has one incident surface 8d, one total reflection surface 12d, and one exit surface 13d. According to the shape of the crystal 14d, the condenser mirror and the objective mirror, which are schematically shown in the figure, are arranged on axes perpendicular to each other. The sample 16 is brought into contact with the total reflection surface 12d for measurement.

In the reference example shown in FIG. 5 (b), a columnar precrystal 14d having a right-angled triangle in cross section is used, and a plane mirror 21 for reflecting infrared light is equilibrated with the total reflection surface 12d. The plane mirror 21 is arranged, and is integrally formed with the crystal 14d by a suitable connecting means (not shown). Therefore, this plane mirror 21 corresponds to the first reflective surface 10b in substantially the crystals 14b, this reference
The example is substantially the same as the above-described reference example of FIG.

[0050](Operation of Reference Example 1)  BookReference exampleIs basically the same as that of the second embodiment.
It is. However, if the number of reflections inside the crystal is one or
Is only twice, the incident optical axis and the reflected optical axis are shifted
The points are different. When performing surface analysis or line analysis in a certain direction
Of the focal point from the reflective surface at
Movement of the sample stage 17 for
Embodiment 2 also describes the necessity of adjusting the focus of the objective mirror 18.
Is the same as

[0051](Effect of Reference Example 1)  BookReference exampleIs basically the same as the effect of the second embodiment.
It is like. Note that a columnar crystal with a relatively simple cross-section
To change the total reflection condition (incident angle of infrared light)
Infrared light can be guided to any part of the sample surface without
There is an advantage that can be.

[Embodiment 3 ] (Structure of Embodiment 3) This embodiment is one embodiment of the third invention. Sample table 17 in the infrared total reflection absorption measuring apparatus of the second embodiment.
The following control system can be added to the drive mechanism described above to automatically adjust the movement of the sample stage 17 in line analysis or surface analysis. Although not described in detail, the infrared total reflection reflection measuring apparatus of Reference Example 1 can be similarly applied. This system predicts and calculates the shift of the focal point of the objective mirror 18 from the measurement point when the crystal 14 is translated in an arbitrary direction, and then calculates the outgoing light necessary to eliminate the shift based on the predicted value. The correction movement amount along the axis is calculated, and the drive mechanism is driven according to the calculation results.

The above control system is specifically, for example,
In the infrared total reflection absorption measurement performed by moving the measurement point and focusing on the moved measurement point, the refractive index of the columnar crystal and the exit aperture angle in the air of the luminous flux reflected by the total reflection surface (exit from the crystal First calculating means for calculating the exit aperture angle of the light beam in the crystal body from the angle of the light beam to the objective mirror), the normal line on the total reflection surface, and the emission optical axis of the total reflection light on the total reflection surface The first to memorize the angle made with
The storage optical means, and the emission optical axis direction of the total reflection light is the z-axis direction, and the column direction of the crystal body that is orthogonal to the z-axis direction is the y-axis direction, and is orthogonal to the y-axis direction and the z-axis direction. Second storage means for storing an x component of a vector from a measurement point before movement to a measurement point after movement when the direction is the x-axis direction;
Second calculating means for calculating a distance by which the crystal is moved in the z-axis direction based on an exit aperture angle in the air and the crystal and an x-component of the vector, and an x-component of the vector and a z-axis direction Means for controlling the driving of the sample holder based on the movement of the sample holder.

Further, the above-mentioned control system may include, for example, the y component of the vector from the measurement point before the movement to the measurement point after the movement described above (the component in the column axis direction of the crystal 14).
May be added to a third storage means for storing the information.

(Effect of Embodiment 3 ) In the case where the measurement point is shifted on the xz plane as shown in FIG. 6 using the crystal 14 shown in FIG. think of. When the measurement point on the sample 16 is shifted by moving the crystal body 14 in the direction of the arrow 22 in parallel, the incident position of the infrared light on the crystal body also changes, so that the light beam 23 before the movement is indicated by the light beam 24 after the movement. To the focal point of the condenser mirror (the focal point of the objective mirror)
Will not fit. This displacement can be eliminated by moving the crystal 14 in parallel in the z-axis direction by a required distance.

In order to eliminate this deviation, the first calculating means performs a calculation using the refractive index of the crystal and the exit aperture angle of the light beam reflected by the total reflection surface in the air, and outputs the light beam in the crystal. The aperture angle is obtained and output to the second calculating means. The first storage means stores an angle (reflection angle) between a normal line on the sample-measuring total reflection surface and an emission optical axis of the total reflection light on the total reflection surface, and stores the angle in the second storage device. Output to arithmetic means. Further, the second storage means stores the x component of the vector from the measurement point before movement to the measurement point after movement, and outputs this to the second calculation means.
The second calculating means performs a calculation using these three values, and sets the converging point of the converging mirror (focal point of the objective mirror) at the measurement point after the movement.
Find the moving distance in the z-axis direction necessary to match
Output to means for controlling the driving of the sample holding unit.

In the case where the above-mentioned third storage means is added, this storage means stores the moving distance in the y-axis direction and outputs it to the means for controlling the driving of the sample holding unit.

(Effect of Third Embodiment) According to the third embodiment, the light-collecting point of the light-collecting mirror (the focal point of the objective mirror) when the measurement point is displaced in a direction other than the column axis direction of the crystal body.
Can be automatically eliminated by moving the sample holder. Therefore, in addition to the case where the line analysis is performed along the column axis direction of the crystal body 14 in the section of the second embodiment, the line analysis in an arbitrary direction on the sample surface by the infrared total reflection absorption or a combination of these line analysis is performed. Surface analysis of an arbitrary area on the sample surface can be performed simply and quickly.

[Embodiment 4 ] This embodiment relates to the design of the material of the reflecting crystal and the design of the optical path length of infrared light in the first to fifth inventions.

In order to prevent a decrease in the amount of infrared light incident on the crystal, a reflection surface that does not come into contact with the sample to be measured is coated with a surface treatment film such as aluminum or gold (for example, the light reflection treatment film 11). ). As a result, it is possible to prevent a decrease in the reflectance on the reflection surface, and to suppress the dissipation of the infrared light to the outside of the crystal.

As a material of the crystal, infrared rays are transmitted,
And those having a refractive index of 2 or more, for example, zinc selenide, KRS-5, which is generally used for infrared total reflection absorption measurement,
Although germanium, silicon, or the like can be used, zinc selenide or KRS-5, which has good transparency to visible light, is particularly preferable in order to enable the observation of the sample with the naked eye.

The setting of the optical path length so that the infrared light is focused on the total reflection surface is performed by selecting the crystal constituting material using the refractive index as an index, setting the shape and size of the crystal, and setting the incident aperture angle (incident angle). The angle can be arbitrarily determined by appropriately combining various factors such as setting of the angle of the light beam to be focused on the condenser mirror and the exit aperture angle, and setting of the relative positions of the crystal, the condenser mirror, and the objective mirror. As an example, the cross section of the crystal is a parallelogram, the acute angle of which is 45 °, the entrance aperture angle and the exit aperture angle are each 60 °, and the thickness and the refractive index of the crystal in the optical axis direction are each 6 mm. And 2.4, the appropriate optical path length inside the crystal is 16.3 mm.

Example 1 In this example, a crystal made of zinc selenide and having the sectional shape shown in FIG. 2 was used. In this cross-sectional shape, the bending angle of the central bending portion was 90 °, the total length in the vertical direction of the crystal was 6 mm, the lengths of the bottom and top sides were 5.15 mm, and the lengths in the column axis direction were 15 mm. The crystal is attached to a holder (not shown) and placed in an optical system of an infrared microscope as shown in FIG. 3, and the sample to be measured is held in a state of being in contact with the total reflection surface as shown in the figure. The objective mirror was focused on this total reflection surface.
In this embodiment, the entrance aperture angle and the exit aperture angle are each 60 °, and the optical path length inside the crystal is set so that the focal point of the condenser mirror and the focal point of the objective mirror are located on the total reflection surface. Is set.

The sample to be measured has a thickness of 12 μm
A cross section of the polyvinylidene fluoride film was used, and the cross section was brought into close contact with the crystal to measure the infrared total reflection absorption spectrum of infrared light reflected from a 10 μm square visual field. FIG. 7 shows the measurement results. A clear infrared total reflection absorption spectrum was measured for the section having a width of 12 μm.
This shows that measurement of an extremely small area on the order of μm is sufficiently possible.

[Embodiment 2] As shown in FIG.
Asbestos on the same total reflection surface using the same crystal 14 as
The surface of the composite material composed of resin and cashew dust was brought into close contact with a sample 16 to be measured, and line analysis was performed in the direction of the arrow in the figure, to thereby obtain 160 infrared total reflection absorption spectrum diagrams sequentially. From this, select the characteristic absorption band specific to each component of asbestos, resin and cashew dust,
The absorption intensity was plotted against the measurement position. FIG. 9 shows the result. In the figure, 25 (dotted line graph) is a resin,
26 (solid line graph) shows asbestos distribution, and 27 (dashed line graph) shows cashew dust distribution on the sample surface. Thus, the distribution state of each component on the composite material surface could be clearly discriminated.

Example 3 Using the same crystal as in Example 1,
Fine particles of red ink were applied to the same total reflection surface and visually observed with an infrared microscope. Although the image of the ink particles was flattened because the observation surface was inclined by 45 °, the image was clearly observed, and the infrared total reflection absorption spectrum of the ink particles could be measured as it was. As described above, by focusing the objective mirror on the total reflection surface, the infrared total reflection absorption spectrum can be measured while observing an extremely small object.

[Embodiment 4] In the infrared total reflection absorption measuring apparatus of Embodiment 1, a control system shown in FIG. 10 was added as a drive mechanism control means for automatically performing line analysis and surface analysis. The control system includes a means 28 for storing a refractive index n, a first storage means 29 for storing an angle i of a half of the exit aperture angle of the totally reflected light beam in the air, a normal line on the sample surface, an output optical axis, Means 30 for calculating an angle r of a half of the exit aperture angle of the totally reflected light beam in the crystal body, and second means for storing a moving distance lx in the x-axis direction. A storage means 32, a second calculation means 33 for calculating a moving distance lz in the z-axis direction,
It includes a control unit 34 for the sample holding unit and a motor 35 for driving the sample holding unit. The x-, y-, and z-axis directions in FIG. 10 correspond to those in FIG.

The calculation of the moving distance lz in the z direction performed by the second calculating means 33 is performed as follows. As shown in FIG. 11, while the focal point of the infrared light and the focal point of the objective mirror are located on the total reflection surface 12, the reflected light flux 36 to the objective mirror before the measurement point is moved.
However, when the reflected light flux 37 to the objective mirror after the movement of the measurement point is shifted, the distance from the emission surface 13 before and after the movement of the measurement point to the focal point of the objective mirror in the air is l _zb1 , l _za1 , and the distance before and after the movement of the measurement point. _Assuming that the distances from the exit surface 13 to the focal point in the crystal of the objective mirror are l _zb2 and l _za2 , it is necessary to set l _zb1 to adjust the focal point of the objective mirror before the movement to the measurement point on the total reflection surface 12 after the movement. The sample holder may be moved in the z-axis direction by −l _za1 = l _z .

Then, the relationship of FIG. 11 is _expressed by an equation: l _za1 · tan i = l _za2 · tan r (3) l _zb1 · tan i = l _zb2 · tan r (4) l _zb2 -l _za2 = l _x · tan θ (5) n = sin i / sin r (6)

The moving distance l _z = l _{zb1 in the z} -axis direction to be obtained
Substituting (3) and (4) the -l _za1, by substituting _{l z = (l zb2 -l za2} ) · tan r / tan i This equation (5), l _z = l _x · tan θ · tan r / tani tan r is given by equation (6) if i is given.
_z can be determined if θ, i, and n are given.

In this embodiment, an objective mirror having an exit aperture angle of 60 ° in air and a crystal having a refractive index of 2.4 and an angle of 45 ° between the normal to the total reflection surface and the exit optical axis are used. , When the moving distance l _x of the measuring point in the x-axis direction is 100 μm, the moving distance l _z of the measuring point in the z-axis direction is calculated.
Was determined as 37 μm. The sample holding unit was driven based on this numerical value, and a line analysis in the x-axis direction was performed.

[Embodiment 5] FIG.
It was added a third storage means 38 for storing the moving distance l _y in the y-axis direction of the system (see Figure 12). This system enables line analysis and surface analysis in any direction. Further, an actuator controller 39 is arranged between the control means 34 of the sample holding unit and the driving motor 35 of the sample holding unit, and a position sensor 40 for detecting a moving distance is provided in the sample holding unit. Actuator controller 39
Can drive the drive motor 35 of the sample holder based on the command of the control means 34 of the sample holder. The drive motor 35 can be driven by directly inputting the moving distance of the measurement point.
Can also be driven. Further, the signal of the position sensor 40 may be fed back to the control unit 34 of the sample holding unit or the actuator controller 39 to move the sample holding unit accurately. According to this embodiment, it is possible to configure a high-precision automatic system with almost no focus shift at each measurement point.

Reference Example 2 In this reference example , a columnar crystal 41 made of zinc selenide and having a parallelogram cross-sectional shape shown in FIG. 13 was used.
In this cross-sectional shape, the angle of the acute angle portion is 45 °, the total length in the vertical direction of the crystal is 6 mm, and the lengths of the base and long sides are 10.
3 mm, and the length in the column axis direction was 15 mm. Such a crystal was attached to a holder (not shown) and arranged in an optical system of an infrared microscope (not shown) as in the case shown in FIG. Note that the optical axis of the focusing mirror is 1 ° with respect to the optical axis of the objective mirror.
It was shifted by 0.3 mm. Then, the objective mirror was focused on this total reflection surface. Note that the entrance aperture angle and the exit aperture angle in this optical system were each set to 60 °, and the focal point of the condenser mirror and the focal point of the objective mirror were set on the total reflection surface.

As the sample 16, fine particles of red ink having a diameter of 50 μm were applied to the total reflection surface of the crystal 41 as shown in FIG. Infrared light reflected from a 10 μm square field of view of the fine particles was narrowed by a slit and sent to a detector, and an infrared total reflection absorption spectrum was measured. Fig. 15 shows the measurement results.
As shown in the figure, a clear infrared total reflection absorption spectrum was measured, indicating that measurement of a small area of the order of 10 μm was sufficiently possible.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are explanatory diagrams of a reflection angle for determining the shape of a crystal, FIGS. 1 (c) and 1 (b).
(D) is an illustration of a crystal.

FIG. 2 is a main part view showing a use state of a crystal.

FIGS. 3 (a) and 3 (b) are overall views showing a use state of a crystal.

FIGS. 4 (a) to 4 (c) are other exemplary views of a crystal.

FIGS. 5 (a) and 5 (b) are views showing a use state of a columnar crystal having a right triangular cross section.

FIG. 6 is a diagram showing a shift of a converging point when the crystal is moved in the x-axis direction.

FIG. 7 is an infrared total reflection absorption spectrum of polyvinylidene fluoride of Example.

FIG. 8 is a perspective view of a crystal body in contact with a composite material.

FIG. 9 is a diagram showing the results of infrared total reflection absorption measurement of a composite material.

FIG. 10 is a block diagram showing a control system.

FIG. 11 is a diagram for explaining calculations performed in the control system.

FIG. 12 is a block diagram showing another example of the control system.

FIG. 13 is a main part view showing a use state of the crystal.

FIG. 14 is a perspective view of a crystal to which a red ink as a sample to be measured is applied.

FIG. 15 is a diagram showing the results of infrared total reflection absorption measurement of fine particles of red ink.

16 (1) to 16 (3) are views showing a conventional crystal and a method of using the same.

FIG. 17 is a diagram showing a method of measuring total infrared reflection absorption in a conventional example.

[Explanation of symbols]

 Reference Signs List 8 entrance surface 9 reflection surface 10 reflection surface 11 reflection surface 12 reflection surface 13 emission surface 14 crystal 16 sample 17 sample stage 18 objective mirror 19 focusing mirror 20 slit

Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 21/00-21/61

Claims (5)

(57) [Claims] An optical path length is set so that the following light-emitting point is located on the total reflection surface of the crystal of (c), including the following elements (a) to (e): Wherein the optical axes of the condenser mirror and the objective mirror are arranged on the same axis. (B) placed on the collector mirror for focusing infrared light (b) a sample holder for holding the measurement specimen (c) the sample holding portion, the infrared light from the focusing mirror is incident A crystal body having an incident surface, a total reflection surface for bringing the sample to be measured in contact with the sample to perform total infrared reflection measurement only once, and an emission surface from which infrared light is finally emitted ( (2) an objective mirror that is arranged to face the emission surface of the crystal and is capable of focusing on a measurement point of the sample to be measured that is in contact with the total reflection surface; Slit to sort 2. The crystal of (c) is a columnar body in which the incident surface, the total reflection surface and the exit surface are formed as planes parallel to the column axis, and is provided in a direction perpendicular to the exit optical axis. 2. The infrared total reflection absorption measurement according to claim 1, wherein the sample holder of (b) has a driving mechanism capable of moving the crystal in parallel along at least the column axis direction of the crystal. apparatus. 3. The crystal of (c) is a columnar body in which the incident surface, the total reflection surface and the exit surface are formed as planes parallel to the column axis, and is provided in a direction perpendicular to the exit optical axis. And the sample holder of (b) has a drive mechanism capable of arbitrarily translating the crystal of (c) in a three-dimensional direction, and the drive mechanism further comprises: Means for predicting and calculating the deviation from the focal point of the measurement point when moving in parallel in different directions, and means for calculating a corrected movement amount along the emission optical axis required to eliminate the deviation based on the predicted value; The infrared total reflection absorption measuring apparatus according to claim 1, further comprising a control system including a control unit configured to drive the driving mechanism according to a result of the calculation. 4. A crystal body mounted on a sample holder for holding a sample to be measured in the infrared total reflection absorption measuring apparatus, wherein an incident surface on which infrared light from a condenser mirror is incident is provided. A total reflection surface for performing total reflection measurement of infrared light by bringing a measurement sample into contact with the sample, at least three reflection surfaces (including the total reflection surface) for changing the direction of incident light, and infrared light Has a light exit surface that finally emits light, and the mutual angle of each reflection surface is configured so that the optical axis of the incident light coincides with the light axis of the output light. . 5. The columnar body according to claim 1, wherein the crystal according to claim 4 is a columnar body in which the incident surface, the total reflection surface, and the exit surface are formed as planes parallel to a column axis. 4. A method as claimed in claim 1, wherein the converging mirror and the objective mirror are used as the crystal in the infrared total reflection absorption measuring apparatus in which the converging mirror and the objective mirror are arranged on the same axis. 2. The infrared total reflection absorption measurement device according to 1.