JPS61122547A - Measuring method of light absorption characteristic of thin film - Google Patents

Abstract

PURPOSE:To find light absorption characteristics of a thin film with high preci sion by providing the thin film expanded on a liquid surface and a mirror sur face below it, making exciting light incident on the thin film from the liquid side and reflecting its reflected light by the mirror surface, and passing probe light nearby the irradiated position and detecting the quantity of polarization. CONSTITUTION:The thin monomolecular layer film 4 is expanded on the liquid surface in a liquid tank 1. Further, the mirror surface 13 is provided under the thin film 4. Then, the exciting light 11 from an exciting light source 10 is made incident on the thin film 4 from the liquid side and reflected totally, and its reflected light is reflected totally by the mirror surface 13. Further, the probe light 6 is passed between the thin film 4 and mirror surface 13. At this time, the exciting light 11 is reflected multiply by the thin film 4 and mirror surfaces 13, so the probe light 6 is polarized greatly through a wide polarizing area and the quantity of polarization is detected 7 to find the light absorption characteristics of the thin film. Thus, the thin film is irradiated with the exciting light from the liquid side to form a multiple reflection area, so the light absorp tion characteristics of the thin film are measured with the high precision.

Description

Detailed Description of the Invention [Industrial Application Field 1] The present invention particularly relates to a method for optically measuring the characteristics of a thin film developed on a liquid surface. The present invention relates to a method for measuring light absorption characteristics that is the basis of analysis.1 For example, when forming a monomolecular cumulative film,
It is used to analyze the characteristics of monomolecular films spread on the liquid surface for accumulation. .

[Prior art] Conventionally, the method for measuring the light absorption characteristics of a certain sample is as follows:
There is a method of determining light absorption characteristics from transmittance or reflectance.

However, when a sample is irradiated with light, there is scattered light in addition to the 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. .

A method for directly measuring the absorption component of light is a measurement method that utilizes the fact that when a sample is irradiated with light intermittently, the light energy absorbed by the sample is intermittently converted into heat through a non-radiative relaxation process. Photoacoustic spectroscopy
ic Spectrogcopy (PAS) and Photothermal Radiation Spectroscopy (PAS)
etry: PTR).

The PAS method can be divided into the microphone method and the piezoelectric element method depending on the type of detector, but the microphone method requires the sample to be placed in a sealed sample chamber, while the piezoelectric element method poses problems with the placement of the detector and sample, and eventually It is also unsuitable for measuring thin films spread on the liquid surface. Furthermore, since the PTR method uses an infrared detector, it has the disadvantage of being susceptible to atmospheric changes such as water vapor.

On the other hand, as a method to directly measure the absorption component of light,
Photothermal deflection spectroscopy
ction 5pectroscopy: PDS
) There is a way to say. This PDS method utilizes the fact that as heat is generated due to absorption of light 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 method 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 based on this PDS method.

The PDS method described above is based on the arrangement of excitation light and probe light.
transverse ffl and vertical direction (
There are two types (callinear) type, and 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 a position sensitive detector (PSO) can be used as the detector. many.

FIG. 9(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.

The light is focused by a lens 34 and irradiated onto the sample 4'. The probe light 6 emitted from the probe light source 5 passes through the region of the sample 4' that is irradiated with the excitation light 11 by the lens 3≦ and the optical path adjuster 18 such as a mirror, and reaches the detector 7, as shown by the dotted line. The amount of deflection when the beam is deflected is measured. FIG. 9(b) shows an example of the horizontal type, which is the same as the vertical type except that the probe light 5 is irradiated parallel to the surface of the sample 4'.

The theoretical treatment of this PDS method 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 intensity of the excitation light, the temperature coefficient of refractive index (T), The term proportional to the light absorption coefficient of the sample is (T).
Included in one. Further, (an/&) can take either a positive or negative value depending on the sample, which indicates that the deflection angle can also be positive or negative.

However, if this PDS method is directly applied to the measurement of a thin film spread on a liquid surface, the following problems will occur because the thin film that is the sample is extremely thin. Here, the thin film spread on the liquid surface refers to a thin film, such as a monomolecular film, that is spread out 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 susceptible to the effects of the external environment before it reaches the liquid surface.1For example, it is susceptible to the effects of dust and fluctuations in the air. In addition, 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 1M degrees and high 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.

[Problems to be Solved by the Invention] The present invention solves the problem of thin I11. ．． The problem to be solved is to be able to measure the light absorption characteristics of extremely thin samples under unique environments with high precision and sensitivity.

[Means for Solving the Problems] The means taken to solve the above problems in the present invention is to perform the measurement while intermittently irradiating excitation light onto the measurement site of the thin film developed on the liquid surface. When irradiating probe light onto a site or its vicinity and measuring light absorption characteristics from the amount of deflection of this probe light, the excitation light is directed from the liquid side at an incident angle that is totally reflected by the liquid surface of the first measurement site. Along with irradiating
The object of the present invention is to provide a method for measuring light absorption characteristics of a thin film in which this reflected light is reflected below the liquid surface at an angle at which it is totally reflected by the liquid surface of at least a second measurement site.

[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 POS method.

By the way, in the present invention, the sample is an NF developed on the liquid surface.
M, and the excitation light is irradiated from the liquid side so that it is totally reflected on the liquid surface on which the thin film is developed. Since the excitation light passes through the liquid and irradiates the thin film, the excitation light irradiated onto the thin film is not affected by dust or fluctuations in the air, unlike when it is irradiated through the air.
The transmitted light that is totally reflected at the liquid surface and passes into the gas phase above the liquid surface is
Since it is very small, on the order of the wavelength of the Evanescent 7 cent wave during irradiation, there is no need to worry about the transmitted light affecting the measured value, and the excitation light is regularly reflected on the liquid surface. Therefore, there will be no adverse effects caused by irregularly reflected light. Furthermore, the excitation light is multiple-reflected between the liquid surface and below the liquid surface, and multiple measurement sites are irradiated with the excitation light, increasing the area where the probe light is deflected. The angle becomes larger, making it possible to perform highly sensitive detection.

[Example] In Fig. 1, l is a liquid tank containing liquid 2.

A thin film 4 as a sample is developed on the liquid surface 3. The thin film #f4 shown in the figure schematically represents a monomolecular film.

A probe light [5] is provided on the side of the liquid tank l. The probe light source 5 emits probe light 6 directly below the liquid surface 3 in a direction parallel to the liquid surface 3. In addition, at positions opposite to each other across the probe light [5 and liquid/fal,
A detector 7 is provided to detect the position of the probe light 6 sent.

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 irradiates excitation light 11 toward the thin film 4 from the liquid 2 side at an angle at which it is totally reflected by the liquid surface 3 on which the thin WA 4 is developed. A collar 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. Slightly below the optical path of the probe light 6 below the liquid level 3 is the liquid level 3.
A mirror surface 13 is provided in parallel with , which further reflects the excitation light 11 that has been totally reflected on the liquid surface 3 , multiple-reflects the excitation light 11 between the liquid surface 3 and the mirror surface 13 , and causes multiple reflections of the IiI film 4 . Excitation light 11 can be irradiated onto the measurement site. Further, an absorber 14 for absorbing the excitation light 11 is provided at a position where the excitation light 11 emitted from the excitation light source 1O and multiple-reflected between the liquid surface 3 and the mirror surface 13 exits the liquid tank l. ing.

The chopper 12 is connected to a lock-in amplifier 9, and the signals of all the detectors 7 can be synchronously detected using a signal indicating the intermittent state of the excitation light 11 sent from the chopper 12 as a reference signal. Probe light source5. The excitation light source lO, the chopper 12, and the lock-in amplifier 9 are each connected to a measurement controller 15. Measurement and measurement controller 15
are the optical path and wavelength of the probe light 6 and the excitation light 11, and the excitation light by the chopper 12! ! In addition to controlling the intermittent interval of the lock-in amplifier 9, the light absorption characteristics are calculated based on the signal from the lock-in amplifier 9.

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, it is not necessary to make the entire part transparent.Also, if the liquid 2 has a small absorption of the excitation light 11, it may have some direct influence on the probe light 6. Although it does not adversely affect the measurement so much, it is preferable that it be transparent.

First, the excitation light 11 emitted from the excitation light source 1o is modulated into intermittent light by the chopper 12, and is spread on the liquid surface 3 of the liquid ml. The first measurement site of 4 is irradiated from below the liquid level 3. At this time, the excitation light 11 has an incident angle of 2
It is incident on the liquid z so that it is larger than the critical angle of z, is totally reflected on the liquid surface 3, is further reflected on the mirror surface 13, and after repeating this process and irradiating the second, third, and so on measurement sites, the liquid z It passes through the inside and exits the liquid tank 1. Only a very small amount of light, on the order of a wavelength, seeps into the gas phase above the liquid surface 3 as evanescent or centrifugal waves during total reflection. Excitation light 11 emitted from liquid tank 1 is absorbed by absorber 14, and unnecessary light is cut off. In the area on each measurement site where the intermittent excitation light 11 is totally reflected, a thin! lI4 absorbs light and generates heat intermittently through a non-radiative radiation process, resulting in an intermittently changing refractive index in the vicinity. .

On the other hand, the probe light 6 emitted from the probe light source 5 is
Because it passes parallel to liquid level 3 directly below liquid level 3.

It passes through a region where the refractive index changes intermittently due to the irradiation of the excitation light 11. When the probe light 6 emitted from the probe light source 5 passes through the vicinity of each measurement site where the refractive index changes intermittently, the optical path is deflected as shown by the dotted line according to the changed refractive index distribution. Become.

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 chopper 12 at the same time it receives the signal from the detector 7, and by synchronizing both signals, the excitation light 11
Light reception position signal of probe light 6 during irradiation and excitation light! ! The light reception position signal of the probe light 6 during non-irradiation is divided into sections with a good S/N ratio and sent to the measurement controller 15. The measurement controller 15 is
Based on this sent signal, the amount of deflection of the probe light 6 with respect to the wavelength of the excitation light 11 at that time is determined, and the light absorption characteristics are calculated based on this. Furthermore, by performing similar measurements while sequentially changing the wavelength of the excitation light 11, the spectral absorption characteristics of the thin film 4 can be obtained.

In this measurement, the measurement site can be freely selected by adjusting the optical path of the excitation light 11 with the measurement control 4115, and the optical path of the probe light 6 can also be adjusted with the measurement controller 15 depending on the position of the liquid level 3. to ensure accuracy. Also,
It is also possible to automatically make all necessary adjustments to the probe light source 5, excitation light source 1O, and tipper 12 by the measurement controller I5, thereby simplifying the operation.

Assuming that the angle of incidence θ, the distance d between the mirror surface 13 and the liquid surface 3, and the reflection area are as follows, the number of times N of excitation light irradiation is expressed by the following equation.

That is, the relationship N=jL/(2dtanθ) is established.For example, intersection=30m, d−0,5×.

If it is θ-eo'', it becomes N''418, which makes it possible to increase the sensitivity by about 18 times.

The light energy absorbed by the thin beam 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. 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 characteristics are
It may be selected as appropriate depending on the purpose of the zero constant.

The probe light 6 is coupled to the excitation light 11 as shown in FIG.
At the same time, the light may be totally reflected at the measurement site. In this case, it is possible to pass through a portion of the liquid 2 where a large change in refractive index occurs, and there is an advantage that highly sensitive measurement can be performed.

As shown in FIG. 3, the probe light 6 can also be passed through a gas phase near the liquid surface 3 and placed under the influence of a change in the refractive index of the gas phase. In this case, the probe light 6 and the excitation light 11 do not intersect at all), so the influence of the excitation light 11 intersecting the probe light 6 can be eliminated.

As shown in FIG. 4, a part of the liquid surface 3 where thin M44 is deployed is partitioned off by a partition frame 1B, and a liquid surface 3 without thin M44 is separated.
It is also possible to form a liquid level 3' and measure this liquid level 3' as a reference liquid level. That is, the probe light 6 emitted from the probe light source 5 and the thiobium 1 emitted from the excitation light source 10
2, the excitation light 11 is passed through optical path splitting means such as a beam splitter or a half mirror! ? After the light is divided by , the probe light 6 and the excitation light 11 are simultaneously sent to the liquid surfaces 3 and 3' using an optical path FA adjusting means 18 such as a mirror. And liquid level 3.3
The amount of deflection of the probe light 6 corresponding to ' is detected by each detector 7, and measurement is performed based on the difference between the two. In this way, the difference due to the presence or absence of the thin film 84 can be measured, and other influences can be canceled out, making it possible to perform highly accurate measurements.

Furthermore, as shown in FIG. 5, the probe light 6 is applied to a medium ls with a large refractive index change, such as a lithium niobate crystal, a titanium oxide crystal, a silicon dioxide crystal, a glass, or a plastic, which is provided near the liquid surface 3. You can also pass it inside.

That is, the heat generated by light absorption by the thin film 4 on the liquid surface 3 is applied to a medium 13 with a large thermal refractive index change placed near the thin film 4 in parallel to the liquid surface 3, and converted into a refractive index change. By passing the probe light 6 through the medium IS, the amount of deflection of the probe light 6 can be expanded, and highly sensitive detection can be achieved.

The measurement of light absorption properties according to the present invention is useful when obtaining a monomolecular cumulative film as shown in FIGS. 6 and 7 in a liquid bath lt.

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

In the New Experimental Chemistry Course Vol. 18, pp. 438-507 Maruzen), the monomolecular film formed on the liquid level 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 is obvious 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 clear 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. The present invention can be used to analyze whether a monomolecular film developed on the liquid surface 3 can be transferred onto the substrate 20 as it is. less than.

The liquid tank I and its procedure for obtaining a monomolecular cumulative film will be explained.

As shown in FIGS. 6 and 7, an inner frame 21 made of, for example, polypropylene is suspended horizontally inside a shallow and wide rectangular liquid tank 1 containing a liquid 2. 3'
is in charge of 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 . The film forming frame 22 is 1
It 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 and right directions 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 . Further, a magnet 25 fixed on the film forming frame 22 and a counter magnet 2B which can be moved from side to side in the figure above the film forming frame 22 and repel each other when approaching the magnet 25 are provided. Accordingly, the film forming frame 22 can be moved to the left and right in the figure and can be stopped. like this! There is also a system in which the film forming frame 22 is directly moved using a one-rotation motor or a pulley instead of the lI weight 23 or the set of magnets 25,213.

Suction nozzles 28 connected to a suction pump (not shown) via a suction pipe 27 are provided on both sides of the inner frame 21.
are lined up. This suction nozzle 28 quickly removes unnecessary monomolecular films from the previous process on the liquid level 3.3' in order to prevent impurities from getting into the monomolecular film or monomolecular cumulative film. It is used to remove still,
Reference numeral 20 denotes a substrate that is attached to a substrate holder 29 and is vertically moved up and down.

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 2B to purify the liquid surface 3.3'. The film forming frame 22 is moved to the left end of the liquid surface 3.3' that has been cleaned in this way, and a film is prepared by dissolving it in a volatile solvent such as benzene or chloroform at ~5X10-)■an/1(7)W degrees. A few drops of the solution of the constituent substances are dropped onto the liquid surface 3 using a dropper or the like. When this solution spreads over the liquid surface 3 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 neatly aligned, resulting in a high degree of order and uniform ultra-thin film properties. At this time, the monomolecular film that has become a solid film can be attached to the surface of the substrate 20 and transferred. Furthermore, a monomolecular cumulative film can be obtained by stacking and transferring a monomolecular film multiple times onto the same substrate. still,
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 2o. - is the vertical immersion method, and the others are the horizontal attachment method. The vertical immersion method is a method in which the monomolecular film is transferred by moving the substrate 2G up and down in the direction across the film, that is, in the vertical direction, while applying a constant surface pressure suitable for cumulative operation to the monomolecular film on the liquid level 3. This is the way to take it. The horizontal adhesion method is a method in which the substrate 20 is held horizontally, brought as close as possible to the liquid surface 3 from above, and slightly tilted to touch the monomolecular film from one end for adhesion.

In order to carry out the transfer operation under conditions of the monomolecular film suitable for transfer to the substrate 20, the surface pressure of the monomolecular film is measured. Generally, the surface pressure of a monomolecular film suitable for transfer is 15 to 30 dyn/c. Outside this range, the arrangement and orientation of molecules may be disturbed and the film may easily peel off. However, in special cases 1, for example, depending on the chemical structure of the membrane constituents, temperature conditions, etc.
Since the preferred surface pressure value may be outside the above range, the above range is only a rough guide.

The surface pressure of the monomolecular film mentioned above is automatically and continuously measured by a surface pressure measuring device (not shown). There are methods that apply an indirect method of determining the surface tension from the difference in surface tension between the surface 3' and the liquid surface 3 covered with a monomolecular film, and those that apply the method of calculating the surface tension indirectly from the difference in surface tension between the surface 3' and the liquid surface 3 that is not covered with a monomolecular film. There are methods that directly measure the two-dimensional pressure applied to the film-forming frame 22, which floats in separation from the liquid surface 3 covered by the liquid surface 3, and each method has its own characteristics. Furthermore, in addition to the surface pressure, the occupied area per molecule of the monomolecular film and the amount of change thereof are also usually measured. The occupied area and the amount of change thereof are 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 26 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. The movement control of this film forming frame 22 is 1! ! ! After dropping the solution of the constituent substances, the monomolecular film transfer operation begins.This process is carried out not only during the salt application but also continuously during the transfer operation.For example, in the transfer operation, the monomolecular film is
As it is transferred to 0, the surface density of the monolayer molecules on the liquid level 3 decreases, and the surface pressure also decreases. Therefore, it is necessary to move the film forming frame 22 to reduce the area in which the monomolecular film is developed, and to correct the decrease in surface pressure to maintain a constant surface pressure.

As mentioned above, various delicate adjustments are required to obtain a monomolecular cumulative film. However, until now it has been necessary to conduct various experiments to find out what conditions are the optimal conditions, and whether the monomolecular film on the liquid level 3 is in a state suitable for accumulation depends on the surface pressure of 1. It can only be confirmed indirectly through methods such as methods, and it lacks accuracy. By the way 1
If the present invention is used in place of the surface pressure measuring device, the liquid level 3
The characteristics of the monomolecular film above can be detected on the spot, and can be accumulated under optimal conditions each time.

Next, an embodiment suitable for utilizing the present invention when obtaining monolayer molecules will be described with reference to FIG.

A support column 30 is erected on one side of the liquid tank l containing the liquid 2, and a substrate holder 29 holding the substrate 20 is mounted on the support column 30.
is attached so that the substrate 20 can be vertically moved up and down toward the liquid level 3.

An ascending/descending wave J31 is provided at the bottom of the liquid tank l, and a measuring unit 32 is installed above it.

The measurement unit 32 has a generally hollow donut shape, and its inner bottom side is a mirror surface 18, and the measurement unit 32 is arranged so that the mirror surface 13 is located directly below and parallel to the liquid level 3. The position is adjusted by the lifting device i31. This measurement unit 32 includes a probe light source 5. Detector 7. Optical path adjustment means 18 that guides the probe light 6 emitted from the probe light source 5 to the detector 7 through between the liquid surface 3 and the mirror surface 13
a-18c, excitation light source 10. 12. The excitation light 11 emitted from the excitation light source is made into intermittent light. Optical path adjustment means 18d, 1 that reflects the absorber 14 and the excitation light 11 multiple times between the liquid surface 3 and the mirror surface 18 and guides it to the absorber 14.
8e is provided.

Further, the lower portions of both sides of the inner peripheral side of the measurement unit 32 are arranged so that the inside of the measurement unit 32 is partitioned off from the liquid 2 and the probe light 6
This serves as a window portion 33 through which the excitation light 1G passes. still,
22 is a film forming frame for adjusting the surface pressure of the thin H4, which is a monomolecular film.

As explained in FIG. 1, according to the above embodiment, the light absorption characteristics of a thin A4 sheet can be measured with high sensitivity. In particular, according to this embodiment, the light absorption characteristics can be measured while forming the thin film 194 as a monomolecular film, and the characteristics of the monomolecular film that is being formed can be easily analyzed. A monomolecular cumulative film can be made with higher precision. In addition, since the measuring system is linear, it is possible to reduce the influence exerted on the measurement system from the outside world, and it is easy to take it out directly to the liquid tank l.

[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 showing one embodiment of the present invention, FIGS. 2 to 5 are explanatory diagrams of other embodiments, and FIGS. 6 and 7 are liquid tanks for obtaining a monomolecular cumulative film. and explanatory diagram of the procedure, No. 8
The figure is an explanatory diagram of an example suitable for use when obtaining a monomolecular cumulative film, FIG. 9(a). (b) is an explanatory diagram of the prior art. 1: liquid tank, 2: liquid, 3.3': liquid level, 4: thin film, 5 nib lobe light source. 6: Probe light, 7: Detector. 8 driver, 9: lock-in amplifier, 10: excitation light source, 11: excitation light, 12: chotsuno-113: mirror surface,
14: Absorber, 15: Measurement controller, IB = partition frame, 17
: Optical path division, 18, 18a to 18e: Optical path adjustment means, 19: Medium. 20: Substrate, 21: Inner frame, 22: Film forming frame, 23: Weight. 24: Pulley, 25: Magnet, 26 Two pairs of magnets. 27: Absorption pipe, 28: Suction nozzle. 23: Substrate holder, 30: Support column, 31: Lifting device. 32: Measurement unit, 33:! ! Department.

Claims (1)

[Claims] 1) Intermittently irradiating the measurement area of a thin film spread on the liquid surface with excitation light and irradiating the measurement area or its vicinity with probe light, and measuring the light absorption characteristics from the amount of deflection of this probe light. , the excitation light is irradiated from the liquid side at an incident angle such that it is totally reflected by the liquid surface of the first measurement site, and the reflected light is totally reflected by the liquid surface of at least the second measurement site below the liquid surface. A method for measuring the light absorption characteristics of a thin film, which is characterized by reflecting the light at a certain angle.