JPS6239731A - Apparatus for measuring photo-physical properties of membrane - Google Patents

Abstract

PURPOSE:To enable measurement with high sensitivity, by providing an exciting light source for emitting exciting light allowed to irradiate the area to be measured of the membrane provided from the part below the surface of a liquid to the part thereabove at an incident angle totally reflected from the surface of the liquid and a detector for detecting the deflection quantity of probe light passed through the area to be measured. CONSTITUTION:The exciting light 1 emitted from an exciting light source 10 is modulated to intermittent light by a light intensity modulator 12 and the area to the measured area of the membrane 4 above the surface 3 of liquid in a liquid tank 1 is irradiated with the intermittent light through a first mirror 13a while the irradiated light is totally reflected from the surface 3 of the liquid to pass through the liquid 2 and issued to the outside of the tank 1 to be again reflected by a second mirror 13b. The re-reflected light 11 advances in parallel to the surface 3 of the liquid to be again reflected by the mirror 13a to irradiate the membrane 4 and the irradiated light is similarly totally reflected from the surface 3 of the liquid and reflected by a third mirror 13c to irradiate the membrane 4 through the mirror 13a. Prove light 6 emitted from a probe light source 5 passes through a measuring vicinity intermittently changed in refractivity by the irradiation of the light 11 and a light path is deflected as shown by a dotted line. A detector 7 receives this light 6 to send the same to a measuring controller 14 through a driver 8 and a lock-in amplifier 9 and the spectral absorption characteristics of the membrane 4 are obtained in the controller 14.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an apparatus for optically measuring the characteristics of a thin film spread on a liquid surface, and more specifically, to an apparatus for optically measuring the characteristics of a thin film spread on a liquid surface. The present invention relates to a measuring device for light absorption characteristics, which is the basis of
It is used to analyze the characteristics of monomolecular films spread on the liquid surface for accumulation.

[Prior art J] Conventionally, as a device for measuring the light absorption characteristics of a certain sample,
There is a device that determines light absorption characteristics from transmittance or reflectance.

However, when a sample is irradiated with light, there is scattered light in addition to transmitted light and reflected light, and in order to achieve even higher accuracy, it is important to directly measure the absorption component of light in evaluating light absorption characteristics. .

One of the various methods for directly measuring the absorption components of light is a photothermal deflection spectrometer (Phototer+5alDe
Reflection Spectrogcopy: P
There is a device called DS. This PDS device utilizes the fact that as heat is generated due to light absorption by the sample, a temperature distribution occurs within the sample and in the vicinity of the sample, causing a change in the refractive index, which deflects the light incident thereon. That is, the measurement site of the sample is irradiated with excitation light that generates a temperature distribution due to heat generation when the light is absorbed and changes the refractive index, and probe light that measures the amount of deflection caused by the excitation light. The light absorption characteristics of the sample are measured from the wavelength and the amount of deflection of the probe light. This device allows the sample and detection system to be set independently and is suitable for on-site measurement and remote measurement, and the basic principle of the present invention is also the same as this PDS device.

Depending on the arrangement of excitation light and probe light, PDS devices can be of transverse type or longitudinal type.
As mentioned above, both measure the amount of deflection of the probe light according to the amount of excitation light absorbed by the sample, and the detector is a position sensitive detector (PDS).
) is often used.

FIG. 15(a) shows an example of a vertical type, in which excitation light 11 emitted from an excitation light source 10 is turned into intermittent light by a chopper 12, focused by a lens 34, and irradiated onto a sample 4'. The probe light 6 emitted from the probe light source 5 passes through a lens 35 and an optical path adjuster 17 such as a mirror to a sample 4 irradiated with excitation light 11.
' and reaches the detector 7, where the amount of deflection is measured as shown by the dotted line. Figure 15 (
b) is an example of the horizontal type, which is the same as the vertical type except that the globe light 5 is irradiated parallel to the surface of the sample 4'.

Theoretical handling in this PDS device is to solve the heat conduction equation within the sample, and the amount of deflection measured as the deflection angle φ is determined by the excitation light intensity and the temperature coefficient of the refractive index (a n/δT).
, the temperature gradient in the region through which the probe light passes (υT/δx
) will be proportional to the shade. A term proportional to the light absorption coefficient of the sample is included in (δThf)x ). Also (υn/D
T) can take either positive or negative values depending on the sample,
This shows that the deflection angle can be both positive and negative.

[Problems to be Solved by the Invention] However, if this PDS device is directly applied to the measurement of a thin film spread on the liquid surface, the sample thin film
Since the pattern is extremely thin, the following problems occur. Here, the thin film spread on the liquid surface refers to a thin film, such as a middle molecular film, that is spread on the liquid surface without floating or sinking.

In the case of a thin film spread on the liquid surface, the area through which the excitation light irradiates the thin film is short, so the excitation light is affected by the external environment before reaching the liquid surface.1For example, it is affected by the effects of dust and fluctuations in the air. Cheap. Further, the influence of unnecessary reflected light and transmitted light after the excitation light reaches the thin film also causes a decrease in the S/N ratio, making it difficult to perform measurements with good accuracy and sensitivity. In particular, in systems that use a special gas in the gas phase above the liquid surface and utilize interaction with a thin film on the liquid surface, it is necessary to make the gas region through which the excitation light passes as short as possible, but this is difficult to achieve. It is.

The present invention aims to solve the problem of making it possible to measure the light absorption characteristics of a thin film spread on a liquid surface, which is extremely thin and under a unique environment, with high precision and sensitivity. That is.

Means for Solving Problem L] The means taken to solve the above problems in the present invention include a liquid tank containing a liquid that spreads a thin film on the liquid surface, and a An excitation light source is located below the liquid surface and emits excitation light that is irradiated to the measurement site of the VjIIU at an incident angle that is totally reflected at the liquid surface. an optical system that makes the light enter the measurement site at an angle that causes total reflection on the liquid surface; a light intensity modulator that modulates the intensity of the excitation light before it reaches the measurement site; and a globe light source that emits the probe light that passes through the measurement site or its vicinity. , and a detector for detecting the amount of deflection of the probe light that has passed through the measurement site or its vicinity.

The above optical system is composed of a set of at least two mirrors, and an excitation light entrance window is provided in a required part of one of the mirrors, or at least two surfaces of a prism are mirrored. Particularly suitable are mirrors configured as such, with an excitation light entrance window provided at a required portion of any one of the mirrors.

In the light intensity modulator described in E, for example, a chopper is used to intermittent light, and a variable filter or the like is used to vary the intensity of light.

[Function] When the excitation light is absorbed by the thin film that is the sample, the refractive index of the measurement site and its vicinity changes between when the excitation light is irradiated and when it is not irradiated, so this is detected as the amount of deflection of the probe light. By this, the light absorption characteristics can be measured. This principle itself is similar to the conventional PO3 method.

In the present invention, the sample is a thin film spread on a liquid surface, and the excitation light is irradiated from the liquid side so as to be totally reflected on the liquid surface on which the thin film is spread. Since the excitation light passes through the liquid and is irradiated onto the thin film, it is not affected by dust or fluctuations in the air, unlike when the excitation light is irradiated through the air. The excitation light irradiated to the thin film is totally reflected by the liquid surface, and the transmitted light that passes into the gas phase on the liquid surface is very small, on the order of the wavelength as an evanescent wave at the time of total reflection. There is no need to worry about the light affecting the measured values, and since the excitation light is regularly reflected on the liquid surface, there is no need to worry about irregular reflected light. #
It does not produce any sound. Furthermore, the excitation light is reflected many times on the liquid surface and mirror surface, and the measurement site is irradiated with the excitation light multiple times, increasing the total excitation light intensity and the probe light deflection area. The larger the angle, the more sensitive detection can be performed.

"Embodiments" The present invention will be described in detail below with reference to embodiments and drawings thereof.

FIG. 1 is a schematic diagram of one embodiment of the present invention.

In FIG. 1, 1 is a liquid tank containing a liquid 2, and a thin film 4, which is a sample, is developed on the liquid surface 3J:. The illustrated thin film 4 is a schematic representation of an rIi molecular film.

A probe light source 5 is provided on the side of the liquid tank 1. The probe light source 5 emits probe light 6 directly below the liquid surface 3 in a direction parallel to the liquid surface 3. Further, a detector 7 for detecting the position of the probe light 6 sent is provided at a position facing the probe light source 5 with the liquid tank 1 in between.

The signal from this detector 7 is sent to a lock-in amplifier 9 via a driver 8.

An excitation light source 1o is provided slightly below the probe light source 5. The excitation light source 10 has an incident angle that is totally reflected by the liquid surface 3 on which the thin film 4 is developed. Excitation light 11 is irradiated toward the thin film 4 from the side. A light intensity modulator 12 is provided at a position along the optical path of the excitation light 11 before entering the liquid tank 1 for irradiating the excitation light 11 as intermittent light.

First, the excitation light 11 emitted from the excitation light source 10 is modulated into intermittent light by the light intensity modulator 12, and then passes through the first mirror 13a with an open window, and is transmitted through the liquid level of the liquid tank 1. The measurement site of the thin film 4 spread on the liquid surface 3 is irradiated from below the liquid level 3. At this time, the excitation light 11 is incident at an angle of incidence greater than the critical angle of the liquid 2, and when it is totally reflected at the liquid surface 3, it passes through the liquid 2 and passes through the liquid 411! ! 1. Go outside.
The light is reflected again by the second mirror 13b, travels parallel to the liquid surface 3, is reflected again by the mirror surface of the first mirror 13a, and irradiates the thin film 4. The excitation light 11 that was totally reflected by the liquid surface 3 as before was reflected by the third mirror 13c, which is parallel to the second mirror 13b and whose position is slightly shifted, and travels parallel to the liquid surface 3. Thereafter, the light is reflected by another portion of the mirror surface of the first mirror 13a, and the thin film 4 is irradiated. In this way, the liquid level 3 → the mirror 1 of the second mirror 13b-+il
3a-+liquid level 3→third mirror 13c→first mirror 1
By repeating the reflection in the order of 3a, the measurement site of the thin film 4 is irradiated with the excitation light 11 multiple times. In the area on each measurement site where the intermittent excitation light 11 is totally reflected, the thin II layer 4 on the liquid surface 3 absorbs the light and intermittently generates heat due to a non-radiative radiation process, which causes the nearby Changes in refractive index occur intermittently.

The light intensity modulator 12 is connected to the lock-in amplifier 9, and the signal from the detector 7 can be synchronously detected using a signal indicating the intermittent state of the excitation light 11 sent from the light intensity modulator 12 as a reference signal. It has become. Probe light source 5, excitation light source 1O5 light intensity modulator 12, and lock-in amplifier 9
are each connected to the measurement controller 14. The measurement controller 14 controls the optical path and wavelength of the probe light 6 and the excitation light 11 and the intermittent interval of the excitation light 11 by the optical intensity modulator 12, and calculates the optical absorption characteristics based on the signal from the lock-in amplifier 9. It is.

Note that the liquid tank 1 receives at least the probe light 6 and the excitation light 11.
If a transparent window is provided in the part that becomes the optical path, there is no need to make the entire part transparent. In addition, if the liquid 2 has a small absorption of the excitation light 11, the probe light 6
It is preferable that the material be transparent, although it will not have much of an adverse effect on the measurement even if it has a direct effect on the material.

On the other hand, the probe light 6 emitted from the probe light source 5 is
The excitation light 11 passes directly below the liquid surface 3 in parallel to the liquid surface 3.
The beam passes near the measurement site where the refractive index changes intermittently due to the irradiation. The region where this intermittent change in refractive index occurs is detected by the globe light 6 emitted from the probe light source 5.
, the optical path will be deflected as shown by the dotted line in accordance with the changed refractive index distribution.

The detector 7 continuously receives the probe light 6 and sends the receiving position of the probe light 6 to the lock-in amplifier 9 via the driver 8 . The lock-in amplifier 9 receives the signal from the detector 7 and the signal from the light intensity modulator 12 at the same time, and by synchronizing both signals, the lock-in amplifier 9 determines the receiving position of the probe light 6 when the excitation light 11 is irradiated. Signal and excitation light 1
1. The light reception position signal of the Bloby light 6 during non-irradiation is divided into S/N ratios and sent to the measurement controller 14. Measurement controller 14
is the excitation light 1 at that time based on this sent signal.
The amount of deflection of the probe light 6 for one wavelength is determined, and the light absorption characteristics are calculated based on this. Further, by performing similar measurements while sequentially changing the wavelength of the excitation light 11, the spectral absorption characteristics of the fJ thin film can be obtained.

In this measurement, the flooded area can be freely selected by adjusting the optical path of the excitation light 11 with the measurement controller 14, and the optical path of the globe light 6 can also be selected with the measurement controller 14 depending on the position of the liquid level 3. can be adjusted for accuracy. Also,
It is also possible to automatically make all necessary adjustments to the probe light source 5, excitation light source 10, and light intensity modulator 12 by the measurement controller 14, thereby simplifying the operation.

The light energy absorbed by the thin film 4 is determined from the light intensity distribution of the excitation light 11 at the measurement site, the characteristics of the refractive index change due to heat of the liquid 2, the incident beam position of the probe light 6, and the amount of deflection at that time. Therefore, by monitoring the irradiation energy of the excitation light 11 onto the thin film 4 using a photosensor or the like, the absolute light absorption characteristics of the thin film 4 can be obtained from both of them.

Then, by changing the wavelength of the excitation light 11, absolute spectral absorption characteristics can be obtained. Further, the relative spectral absorption characteristics can be obtained by simply determining the relative intensity of the excitation light 11 at each wavelength in advance and determining the amount of deflection of the probe light 6 corresponding to the wavelength. The relative value and absolute value of the light absorption characteristic may be appropriately selected depending on the purpose of measurement.

FIGS. 2 and 3 are explanatory diagrams of the basic principle of the present invention. In FIG. 2, a thin film 4 as a sample is spread on a liquid surface 3, and the excitation light 11 is incident from below the liquid surface 3 at an angle such that it is totally reflected by the liquid surface.
The light is reflected in a direction parallel to the liquid surface 3, and is reflected again by the mirror 13a to illuminate the thin film 4 on the liquid surface 3. At this time, as shown in FIG. 3, the total reflection position of the liquid surface 3 is N, the reflection position of the mirror 13b is R1, the intersection position of the mirror surface and the liquid surface is B, the reflection position of the mirror 13a is L, If the intersection position of the mirror surface and the liquid surface is A, then the incident angle of the excitation light is <
If LNA is 0, the total reflection angle < RNB will also be θ,
If the mounting angle of the mirror 13b is set so that the reflected light 11 of the mirror 13b is parallel to the liquid surface N1, the reflection position ii\t
The angle between the normal M2 in R and the excitation light ratio 1 is 0/2, and the angle between the mirror 13b and the liquid surface is < RBN is 9
θ−θ/2. Also, the excitation light 11 parallel to the liquid surface is
In order for the excitation light 11 to be reflected again in the direction of the N point at the point, the angle between the normal Ml of the mirror 13a and the excitation light 11 should be set to θ/2.
The angle made with < LAN is 90-0/2.

However, in FIG. 3, in the mirror 13a, the transmission position of the excitation light and the re-reflection position of the reflected light from the liquid surface overlap, and it is impossible to increase both transmission and reflection. It is not possible to increase the excitation light intensity. Therefore, by slightly shifting the mounting position of the mirror 13b while keeping the mounting angle the same, the height of the excitation light parallel to the liquid surface changes, and as in the embodiment shown in FIG. They no longer overlap.

FIG. 4 is an explanatory diagram showing another embodiment of the present invention, showing only the portion where the excitation light 11 is irradiated onto the thin film 4 on the liquid surface. The excitation light 11 passes through the open window of the mirror 13a at an angle at which it is totally reflected on the liquid surface 3, and after being totally reflected on the liquid surface 3,
The light is reflected by the mirror 13b so as to irradiate the mirror 13a at a position offset from the liquid surface 3 and the aperture window. The excitation light is reflected again by the mirror 13a, enters the liquid surface 3 at the same angle of incidence as before, is reflected again by the mirror 13b in a direction opposite to the liquid surface 3, and this time passes through the aperture window. When this transmitted light is vertically reflected by the mirror 13d, the transmitted excitation light II returns in the opposite direction along the same optical path, thereby making it possible to irradiate the thin film 4 on the liquid surface four times in total.

5 and 6 are explanatory diagrams of still another embodiment of the present invention. FIG. 5 shows the structure of the part where the excitation light 11 is irradiated onto the thin film 4 on the liquid surface 3, and FIG. shows the principle in which the excitation light 11 totally reflected on the liquid surface 3 is repeatedly irradiated onto the thin film 4 on the liquid surface 3. In this embodiment, the mounting angle of the second mirror 13b shown in FIGS. 2 and 3 is shifted by a small angle (Δθ/2 in the normal direction) from that shown in FIGS. 2 and 3. Therefore, the position at which the reflected light is incident on the first mirror 13a also shifts by that amount. With this configuration, as shown in FIG. 6, the first excitation light irradiation position N
If the angle between the liquid surface 3 and the excitation light 11 is set to 0 at l, the incident angle at the excitation light irradiation position N2 for the second time is 0 - Δθ, and for the third time it becomes 0 again. A thin M4 beam can be irradiated.

7 and 8 are explanatory diagrams of still another embodiment of the present invention, in which FIG. 7 shows the configuration of a portion where the excitation light 11 is irradiated onto a thin layer @4 of the liquid surface 3L, and FIG. The figure shows the principle in which the excitation light 11 totally reflected on the liquid surface 3 is repeatedly irradiated onto a thin layer 4 on the liquid surface 3. This embodiment is different from the one shown in FIGS. 2 and 3. Same mirror arrangement, excitation light L' 1
is incident on the thin film 4 by shifting Δθ from θ to 0−
It is set to Δ0. With this configuration, as shown in FIG. 8, if the angle between the liquid level 3 and the excitation light 11 at the first excitation light irradiation position N1 is 0 - Δθ, then the second excitation light irradiation position N2 The incident angle at is θ+Δ0.The third time it becomes 0- again
The value becomes Δ0, and thereafter the thin film 4 on the liquid surface 3 can be irradiated by repeating θ−Δθ, 0+Δ0 every other time.

9 and 10 are explanatory diagrams of still another embodiment of the present invention, and FIG. 9 shows the structure of the part where the excitation light 11 is irradiated onto the thin film 4 on the liquid surface 3 in a longitudinal section. , FIG. 10 shows the positional relationship between the excitation light 11 and the probe light 6 in a cross section. This embodiment has the same mirror arrangement as shown in FIGS. 2 and 3, but the excitation light 11 and the probe light 6 are An optical system is used in which the incident angle of the light 11 can be varied in the horizontal direction, as shown in FIG.

Therefore, in the vertical cross-sectional view of No. 9I54, the excitation light 11 appears to follow the same optical path at the same irradiation position, but on the actual liquid surface 3, the excitation light 11 is repeatedly reflected while gradually moving the irradiation position of the thin layer 14. It turns out. A large amount of deflection can be obtained by passing the Boulop light 6 directly under the temporary line connecting these moving irradiation positions, as shown by the chain line in FIG.

11 and 12 are explanatory diagrams of still another embodiment of the present invention, in which the excitation light 11 is applied to the thin film 4 on the liquid surface 3.
FIG. 12 shows the configuration of the portion irradiated with a vertical section, and FIG. 12 shows the positional relationship between the excitation light 11 and the probe light 6 in a cross section. This embodiment is composed of a pair of mirrors 13g and 13h, which are partially bent or curved toward opposite sides of the pair of mirrors 13e and 13f shown in FIGS. 9 and 10. Therefore, the irradiation position of the excitation light 11 on the thin film 4 on the liquid surface 3 initially shifts slightly in one direction as in the case of FIG.
When g' and 13h' are reached, the angle of one reflection changes,
The excitation light irradiation position of the thin film 4 moves in the opposite direction and returns to the initial position again. As a result, it becomes possible to limit the area of the excitation light irradiation position to a local area that is not very wide. In addition,
Serious bends or curvatures can be provided on both sides of the shooting point of the mirrors 13g and 13h, and can be further localized.

413 and 14 are explanatory diagrams of still another embodiment of the present invention, and FIG. 13 is a longitudinal section showing the structure of the part where the excitation light 11 is irradiated onto the thin film 4 at the liquid surface 31. 14 shows the positional relationship between the excitation light 11 and the probe light 6 in a cross section. This embodiment shows a pair of mirrors 13e and 13f in the configuration shown in FIGS. 9 and 10. Instead, two surfaces lea and 18b of the prism 16 are replaced, and the excitation light 11 is transmitted through the prism 16.

This method replaces the mirror surface by forming the side surface of the prism into a reflective surface, integrating the optical system and making adjustment easier. It goes without saying that the present invention can be applied not only to this embodiment but also to other parts of the present invention already described.

In the measurement of optical properties according to the present invention, it is advantageous to use a liquid bath as shown in FIGS. 16 and 17 when obtaining a monomolecular cumulative film.

A monolayer accumulation method (hereinafter referred to as the LB method) is called the Langmuir-Prodgett method after the inventor.

In the New Experimental Chemistry Course Vol. 18, pp. 488-507 Maruzen), the monomolecular film formed on the liquid surface 3 is transferred onto the surface of the substrate 20 and layered one by one to form an ultra-thin film. The characteristics of the thin film above 3 are important.

It goes without saying that the structure and molecular orientation of the cumulative film transferred onto the substrate 20 by the LB method are based on the state of the developed monomolecular film on the liquid surface 3, but it is also true that the structure and molecular orientation of the cumulative film transferred onto the substrate 20 by the LB method are based on the state of the developed monomolecular film on the liquid surface 3. There is a question as to whether or not it has been done. In the present invention, the monomolecular film developed on the liquid surface 3 is transferred to the substrate 20 while it is intact.
This can be used to analyze whether it can be transferred to the top. Below, the liquid tank 1 and its procedure for obtaining the vehicle molecule cumulative film will be explained.

As shown in Figure i18 and Figure 17, an inner frame 21 made of, for example, polypropylene is suspended horizontally inside a shallow and wide rectangular liquid tank l containing liquid 2, and the water surface 3,
It separates 3'. As the liquid 2, pure water is usually used. A film forming frame 22 made of, for example, polypropylene is floated inside the inner frame 21 . Film forming frame 22
is a rectangular parallelepiped whose width is slightly shorter than the inner width of the inner frame 21, and is capable of two-dimensional piston movement in the left-right direction in the figure. A weight 23 for pulling the film forming frame 22 to the right in the figure is tied to the film forming frame 22 via a pulley 24.

In addition, a magnet 25 fixed on the film forming frame 22 and a magnet 25 fixed on the film forming frame 22
A pair of magnets 26 is provided above 2, which can be moved left and right in the figure and repel each other when approaching the magnet 25, so that the film forming frame 22 can be moved left and right in the figure and can be stopped. It becomes. Instead of such a weight 23 or a set of magnets 25, 28, there is also a system in which a rotary motor or a pulley is used to directly move the film forming frame 22.

Suction nozzles 28 connected to a suction pump (not shown) via a suction vibrator 27 are provided on both sides of the inner frame 21.
are lined up. This suction nozzle 28 removes unnecessary monomolecular films, etc. from the previous process on the liquid level 3.3' in order to prevent impurities from being mixed into the monomolecular film or monomolecular layer v1@. It is used for quick removal. Note that 20 is a board that is attached to a board holder 29 and is vertically lowered.

First, the film forming frame 22 is moved to sweep up unnecessary monomolecular films and the like on the liquid surface 3.3' while sucking them out from the suction nozzle 28 to purify the liquid surface 3.3'. The film forming frame 22 is brought to the left end of the liquid surfaces 3 and 3' thus cleaned, and the film forming material dissolved in a volatile solvent such as benzene or chloroform at a concentration of, for example, z 5 x 10-'5 of L/fL is deposited. Drop a few drops of this solution onto the liquid surface 3 using a dropper etc.
When this solution spreads on the liquid surface 31 and the solvent evaporates, a monomolecular film is left on the liquid surface 3.

The above-mentioned monomolecular film is called a gas film of a secondary gas when the areal density of molecules exhibiting two-dimensional system behavior on the liquid surface 3 is low, and there is a difference between the occupied area per molecule and the surface pressure. The equation of state for a dimensional ideal gas holds.

Next, from this state of gas film, the film forming frame 22 is gradually moved to the right to gradually reduce the area of the liquid surface 3 where the monomolecular film is developed and increase the areal density, thereby increasing the intermolecular interaction. It becomes stronger and changes from a liquid film of a two-dimensional liquid to a solid film of a two-dimensional solid. In this solid film, the arrangement and orientation of each molecule is perfectly aligned, resulting in a highly ordered and uniform ultra-thin film. At this time, the monomolecular film that has become a solid film can be attached to the surface of the substrate 20 and transferred.

Further, the monomolecular film aPt1 can be obtained by stacking and transferring the monomolecular film multiple times onto the same substrate. Note that, as the substrate 20, for example, glass, synthetic resin, ceramic, metal, etc. are used.

There are roughly two types of methods for transferring the monomolecular film from above the liquid level 3 to the surface of the substrate 20. - is the vertical immersion method, and the others are the horizontal attachment method. The vertical immersion method means that a model of a single molecule on the liquid level 3 is
A is a method of transferring a monomolecular film by lowering the substrate 20 in a direction across the film, that is, in a vertical direction, while applying a constant surface pressure suitable for the transplantation operation. What is the horizontal attachment method?
This method involves holding the substrate 20 horizontally, moving it as close to the liquid surface 3 as possible, tilting it slightly, and touching the monomolecular film from one end to attach it.

The surface pressure of the monomolecular film is measured in order to perform the transfer operation under conditions of the monomolecular film suitable for transferring to the substrate 20 described above. In general, the surface pressure of a monomolecular film suitable for transfer is 15 to 30 db, which tends to disturb the arrangement and orientation of the molecules and cause the film to peel off. However, in special cases, for example, the chemical structure of membrane constituents,
Depending on the temperature conditions, etc., the suitable value of the surface pressure may exceed the above range, so the above range is only a rough guide.

The surface pressure of the monomolecular film is measured manually and continuously using a surface pressure measuring device (not shown). Surface pressure measuring instruments include those that apply a method of indirectly determining the surface tension from the difference in surface tension between the liquid surface 3' that is not covered with a monomolecular film and the liquid surface 3 that is covered with a medium molecular film; There are methods that directly measure the two-dimensional pressure applied to the floating film forming frame 22, which separates the liquid surface 3' that is not covered with a monomolecular film from the liquid surface 3 that is covered with a monomolecular film. , each with its own characteristics. Further, the surface pressure, the area occupied per molecule of the monomolecular film, and the amount of change thereof are usually determined from the left and right movement of the film forming frame 22.

The movement of the film forming frame 22 described above is controlled based on the surface pressure of the monomolecular film measured by the measuring device. That is, a driving device (not shown) for moving the counter magnet 2B from side to side is controlled by a surface pressure measuring device so that the monomolecular film always maintains a constant surface pressure selected within a range suitable for the transfer operation. It is controlled based on the measured surface pressure of the monolayer. This movement control of the film forming frame 22 is performed not only after dropping the solution of the film constituent material until the start of the monomolecular film transfer operation, but also continuously during the transfer operation. In the operation, as the monomolecular film is transferred to the substrate 20, the surface density of the monomolecular film molecules on the liquid surface 3L decreases, and the surface pressure also decreases. Therefore,
Move the film forming frame 22 to reduce the surface area of the monomolecular film,
It is necessary to maintain a constant surface pressure by correcting the decrease in surface pressure.

As mentioned above, various delicate aiI adjustments are required to obtain a monomolecular cumulative film. However, what conditions are optimal has to be determined through various experiments, and whether the monomolecular film on the liquid level 3 is in a state suitable for accumulation depends on the surface pressure. It can only be confirmed indirectly through methods such as methods, and it lacks accuracy. By the way, if the present invention is used in place of the surface pressure measuring device,
It is possible to detect the characteristics of the monomolecular film on the liquid surface 3 on the spot, and to accumulate it under optimal conditions each time.

[Effects of the Invention] According to the present invention, when measuring the light absorption characteristics of a thin film spread on a liquid surface, it is possible to eliminate the influence of reflected light and transmitted light as well as the adverse effects of passing an excitation beam through the air. , it is possible to perform measurements with high sensitivity and high precision.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of one embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams of the basic principle of the present invention, FIGS. 4 to 14 are explanatory diagrams of other embodiments, and FIG. The figure is an explanatory diagram of a conventional example, and FIGS. 16 and 17 are explanatory diagrams of a liquid tank and procedure for obtaining a monomolecular stacked film. 1: Liquid tank, 2: Liquid, 3.3': Liquid level, 4: fiI
Membrane, 5 nib lobe light source, 6: probe light, 7: detector, 8 nib driver, 9: lock-in amplifier, lO: excitation light source, 11: excitation light, 12: light intensity modulator, 13: mirror, 14: measurement Controller °, 16: Prism, 20: Substrate, 2
1: Inner frame, 22: Film forming frame, 23: Weight, 24: Pulley, 2
5: Magnet, 28 pairs of magnets, 27: Absorption pipe, 2nd: Suction nozzle. Figure 2 Basic configuration diagram Figure 3 Figure 4 Configuration diagram of applied array Figure 5 Figure 6 Figure 7 Configuration diagram of applied example Figure 8 Principle diagram of applied example Figure 9 Figure 10 Plane of applied example Figure 11: Configuration diagram of the applied example A. Figure 12: Plan view of the applied example. Figure 13: Configuration diagram of the applied example. Figure 14. Plan view of the applied example. Figure 1b. Explanatory diagram of each cumulative film

Claims (1)

[Claims] 1) A liquid tank containing a liquid that spreads a thin film on the liquid surface;
An excitation light source that emits excitation light that is irradiated from below the liquid surface to the measurement site of the thin film on the liquid surface at an incident angle that is totally reflected by the liquid surface; an optical system that makes the excitation light enter the measurement site again at an angle at which it is totally reflected by the liquid surface; a light intensity modulator that modulates the intensity of the excitation light before it reaches the measurement site; and a probe light that passes through the measurement site or its vicinity. 1. An apparatus for measuring optical physical properties of a thin film, comprising: a probe light source that emits light; and a detector that detects the amount of deflection of the probe light that has passed through the measurement site or its vicinity.