JPH09210848A - Method and apparatus for measurement of transmission and scattering capability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the transmission and scattering characteristic of a sample as separate information separated from an absorption characteristic while a simple apparatus is used. SOLUTION: The transmission and scattering capability of a sample 1 is found in such a way that parallel light L0 at a constant intensity is made incident on the sample 1 and that the quanitity of light of transmitted and scattered light L1 by the sample 1 is detected by using an integrating sphere 2 having a hole 2h on an optical axis L and by using a detector 4 which is connected to the integrating sphere. In this case, the ratio I1 /I2 of the quantity of detected light I1 of the transmitted and scattered light, at a time when the distance between the sample 1 and the integrating sphere 2 is d1 , to the quantity of detected light I2 of the transmitted and scattered light, at a time when the distance between the sample 1 and the integrating sphere 2 is d2 , is found as a straight advance ratio, and the straight advance ratio I1 /I2 is evaluated as the transmission and scattering capability of the sample 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring transmission / scattering ability, which enables easy evaluation of transmission / scattering characteristics of a sample.

[0002]

2. Description of the Related Art Generally, when the light transmission characteristics of a sample are evaluated, when the sample does not have a problem of scattering like plate glass having a smooth surface, parallel light is incident on the sample so that the transmitted light of the sample is also parallel. Since it becomes light, the light transmittance is measured by introducing the transmitted light of the sample into the detector. In this case, when introducing the transmitted light of the sample into the detector, a lens or a mirror is used if necessary.

On the other hand, suspensions, translucent films,
When a clouded glass plate or the like is used as the sample, even if parallel light is incident, the light is scattered at the time of incidence on the sample, so the intensity of the transmitted scattered light of the sample is averaged using an integrating sphere. Introduced into the detector. For example, as shown in FIG. 5, the sample 1 is closely attached to the integrating sphere 2, the parallel light L ₀ is made incident on the sample 1 from the light source 3, and the transmitted scattered light L ₁ of the sample ₁ is detected by the detector 4. Has been done.

In order to examine the scattering angle distribution of the intensity of the transmitted scattered light of the sample in which direction and which intensity, as shown in FIG. Using the detector 4 installed and capable of varying the angle θ with respect to the optical axis L, the light source 3 to the sample 1 is used.
It has been made to detect a different angle θ with respect to the optical axis L of the transmitted scattered light L _1, the detector 4 from the sample 1 when is incident parallel light L ₀ in.

[0005]

However, when the transmitted scattered light L ₁ is detected using the integrating sphere 2 as shown in FIG. 5, from the detected value, the amount of light absorbed by the sample 1 and the forward scattered light are detected. There is a problem in that only the information regarding the total value of the amount of light that has been obtained can be obtained, and the transmission and scattering characteristics of the sample 1 cannot be obtained as separate information that is separate from the light absorption characteristics.

Further, in the detector angle variable type device shown in FIG. 6, in order to change the angle θ of the detector 4, the optical element group associated therewith must be moved, which causes a measurement error or an error. There is a problem that light amount loss occurs, and there is also a problem that the device becomes complicated and expensive.

The present invention is intended to solve the above-mentioned problems of the prior art, and the transmission and scattering characteristics of the sample are
The purpose is to be able to obtain it as separate information separate from the absorption characteristics using a simple device.

[0008]

The present inventor, when obtaining the transmission and scattering characteristics of a sample using an integrating sphere, detects the amount of detected light I ₁ obtained when the sample is separated from the integrating sphere and the integrating sphere. By taking the ratio I ₁ / I ₂ of the detected light amount I ₂ obtained when the sample and the integrating sphere are brought into close contact with each other, it is possible to obtain an index of the transmission / scattering characteristic independent of the absorption characteristic of the sample. It is possible to obtain this index by a simple measurement operation, and therefore, the ratio I ₁ / I
The inventors have found that the object of the present invention can be achieved by evaluating ₂ as the transmission and scattering ability, and have completed the present invention.

That is, parallel light having a constant intensity is incident on the sample, and the amount of transmitted scattered light of the sample at that time is detected using an integrating sphere having a hole on the optical axis and a detector connected to the integrating sphere. a transmissive scattering power measurement method, detecting the light quantity I ₁ of transmitted scattered light when the distance between the sample and an integrating sphere is d ₁
And the distance between the sample and the integrating sphere is d ₂ (however, d ₁ > d ₂ ).
Ratio of the transmitted scattered light to the detected light amount I ₂ I ₁ /
A method for measuring transmission / scattering ability is provided, wherein I ₂ is calculated as a rectilinear movement rate, and the transmission / scattering ability of a sample is evaluated based on the rectilinear movement rate.

Further, the present invention is an apparatus capable of carrying out the method for measuring transmission and scattering power of the present invention, which is a light source capable of making parallel light of a constant intensity incident on a sample, and an integral having a hole on the optical axis. It has a sphere, a detector connected to the integrating sphere to detect the amount of transmitted scattered light from the sample, and a sample stand that holds the sample in a variable position on the optical axis between the light source and the integrating sphere. The present invention provides a device for measuring transmission and scattering power.

According to the method of the present invention, the ratio I ₁ / I ₂ of the detected light amounts when the distance between the sample and the integrating sphere is different is determined as the transmission and scattering ability of the sample. This ratio was newly found by the present inventor as an index of transmission and scattering characteristics, and shows a value that does not depend on the absorption characteristics of the sample. That is, when parallel light with a constant intensity is incident on the sample and the transmitted scattered light from the sample is detected using the integrating sphere, the incident light on the sample is detected in two cases where the distance between the sample and the integrating sphere is different. The amount of light is considered to be the same in both cases, and the amount of light reflected on the sample surface can also be considered to be the same in both cases. Therefore, although the ratio I ₁ / I ₂ of the detected light amounts in both cases changes depending on the distance between the sample and the integrating sphere and the size of the hole of the integrating sphere,
It can be considered to represent a transmission / scattering characteristic value that does not depend on the absorption characteristic of the sample such as the amount of the absorbing substance contained in the sample or the absorption wavelength.

For example, when the transmitted light of the sample is scarcely scattered and has the same parallelism as the incident light, the ratio I ₁ / I of the detected light amounts is irrespective of the distance between the sample and the integrating sphere. ₂
Is considered to be a value close to 1, but when the scattering power of the sample is large, the detected light amount decreases as the distance between the sample and the integrating sphere increases. That is, the amount of light detected when the distance between the sample and the integrating sphere is d ₁ is I _1, and the amount of light detected when the distance between the sample and the integrating sphere is d ₂ is I ₂ (where d ₁ >
When d ₂₎ that, when the scattering power of the sample is large is considered as detected light intensity I ₁ a distance d ₁ between the sample and an integrating sphere is large becomes small and the ratio I ₁ / I ₂ of detected light is reduced . Therefore, in the present invention, this ratio I ₁ / I ₂
Is referred to as a straight traveling rate, and the transmission / scattering characteristic of the sample is evaluated by this straight traveling rate. In particular, the detection light quantity I ₁ of the straight ratio I ₁ / I _2, when the the sample and an integrating sphere which is a certain distance d ₁
By calculating as the ratio of the detected light amount I ₂ when the sample and the integrating sphere are brought into close contact with each other, the transmission and scattering characteristics of various samples can be easily compared and evaluated. Provides the straightness rate as a preferable indicator of the transmission and scattering characteristics of the sample.

As an apparatus for carrying out such a method, a light source capable of making parallel light of a constant intensity incident on a sample, a sample stage for holding the sample, and an integrating sphere having a hole on the optical axis. , It is sufficient if there is a detector connected to an integrating sphere to detect the amount of transmitted scattered light from the sample, but in the apparatus of the present invention, when changing the distance between the sample and the integrating sphere,
It is assumed that the sample stage moves on the optical axis in a variable position. As a result, compared with the case where the installation positions of the integrating sphere and the detector are moved, the optical system associated with the integrating sphere and the detector is not moved, so that an error accompanying the movement does not occur, and the moving means itself. Can be easily configured.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail with reference to the drawings. In addition, in each figure, including the above-mentioned conventional example,
The same reference numerals represent the same or equivalent components.

FIG. 1 is a schematic configuration diagram of the apparatus of the present invention. This device comprises a light source 3 for making parallel light incident on a sample 1.
And an integrating sphere 2 having a hole 2h on the optical axis L.
Connected to the detector ₁ to detect the amount of transmitted scattered light L 1 from the sample 1, and a sample table 5 that holds the sample 1 positionally on the optical axis L between the light source 3 and the integrating sphere 2, It is composed of a base portion 6 that movably holds the sample table 5.

In this apparatus, the light source 3 is not particularly limited as long as it is capable of allowing parallel light to enter the sample 1, and a light source used in a normal transmittance measuring device or the like can be used. However, it is particularly preferable that the light source has a spectral power capable of emitting light of a predetermined wavelength.
This is preferable because it is possible to investigate the transmission / scattering ability of the sample at the incident wavelength and the relationship between the incident wavelength and the transmission / scattering ability.

As the integrating sphere 2, one having a hole 2h on the optical axis L for introducing the transmitted scattered light from the sample 1 is used. In this case, the hole 2h is centered on the optical axis L in particular. A perfect circle is preferred. Also, if the diameter is too small, the accuracy becomes low, and if it is too large, the sensitivity becomes low.
It is preferably about 20 mm.

The sample table 5 may be any one that holds the sample 1 movably on the optical axis L. For example, an angle movably attached to a base 6 such as a rail and a grip for fixing the sample. Alternatively, it can be composed of a frame material. In particular, the sample table 5 is the sample 1 as shown by the broken line in the figure.
So that the position can be brought into close contact with the integrating sphere 2,
It is preferable that the movable range from there is usually about 0 to 300 mm.

In the present invention, when carrying out the method of the present invention using such an apparatus, first, the sample 1 is installed at a position at a distance d ₁ from the integrating sphere 2 and the light source 3 is parallel to the sample 1. Light is made incident and the amount of detected light I ₁ in the detector 4 at that time is obtained. Further, the distance between the sample 1 and the integrating sphere 2 is made different, and the detected light amount I ₂ when the distance between them is d ₂ (however, d ₁ > d ₂ ), and these ratios I ₁ / I
₂ is obtained as the straight traveling rate, and the value of this straight traveling rate is evaluated as the transmission and scattering ability of the sample 1.

In this case, the distance d ₂ between the sample 1 and the integrating sphere ₂
Is set to 0, that is, by bringing the sample 1 into close contact with the integrating sphere 2, the integrating sphere 2 causes the transmitted scattered light L of the sample 1 to pass.
₁ can be collected over all angles. On the other hand, when the sample 1 is separated from the integrating sphere 2 by a constant distance (d ₁ ), the angle α corresponding to the hole 2h on the phantom sphere at that distance
The integrating sphere 2 collects the transmitted scattered light of. Therefore, as described above, the straight-forward rate I ₁ / I _{2 is} calculated as the transmission / scattering ability.
When seeking, as I _2, by using a value when brought into close contact with the sample 1 and the integrating sphere ₂ (d 2 = 0), transmission scattering power of the present invention with respect to the scattering properties of the sample (i.e., straight ahead ratio The sensitivity of I ₁ / I ₂ ) can be increased.

As the apparatus of the present invention, the amount of light detected by the detector 4 is stored, and when the distance between the sample 1 and the integrating sphere 2 is different, the straight traveling rate I ₁ / I ₂ (however, d ₁ > d ₂ ), A personal computer, a display or the like may be incorporated as the calculation means and the output means for outputting the calculation result.

The transmission and scattering ability obtained by the present invention can be used as an evaluation index for various light scattering substances. For example, it can be used to evaluate the transmission and scattering characteristics of suspensions, coating films, light-shielding films, frosted glass plates, and the like.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments.

Example 1 In the apparatus configuration shown in FIG. 1, a deuterium lamp was used as a light source, an integrating sphere 2 having a diameter of 5 cm and a hole 2h having a diameter of 10 mm was used. A photomultiplier tube was used as the container 4.

On the other hand, as sample 1, colorless cloudy glass or brown cloudy glass was attached to the sample table 5, the sample table 5 was moved to bring the sample 1 into close contact with the integrating sphere 2, and light was made incident on the sample 1 from the light source 3 for detection. The light intensity I ₂ was measured by the instrument 4. In this case, the light from the light source 3 to the sample 1 was changed at a wavelength of 350 to 700 nm, and the light amount I ₂ was measured at each wavelength. Next, the distance between the sample 1 and the integrating sphere was set to 50 mm, the wavelength of the incident light was changed in the same manner, and the light amount I ₁ was measured by the detector 4. Then, the ratio I ₁ / I ₂ of the _two was determined as the straight traveling rate. The result is shown in FIG. Further, the amount of light measured by the detector 4 when the sample 1 and the integrating sphere 2 are brought into close contact with each other is 100, and the amount of light measured by the detector 4 when the sample 1 is removed from the optical path is taken as 100. It was calculated as the hourly transmittance (%). The result is shown in FIG.

From FIG. 2, the transmittances of the brown frosted glass and the colorless frosted glass are greatly different, and the colorless frosted glass has a transmittance of 350 to 70.
It can be seen that the brown frosted glass has strong absorption on the short wavelength side, while it has no large absorption in the wavelength range of 0 nm. However, it can be seen from FIG. 3 that the straight traveling rates of the brown frosted glass and the colorless frosted glass are substantially constant regardless of the presence or absence of absorption. Therefore, it can be seen that the straightness rate of the present invention is a characteristic value obtained as separate information that is separate from the light absorption characteristics of the sample, and is an index of transmission and scattering ability.

Example 2 Using a commercially available transparent film for window glass, a blinding film for window glass, and shoji paper as samples, their straightness rates were determined in the same manner as in Example 1. The result is shown in FIG.

On the other hand, the transmission / scattering ability of the window glass film and the shoji paper was visually evaluated in three grades of transparent, semi-transparent and opaque.

[Visual Evaluation Results] Transparent film for window glass: transparent Blinding film for window glass: translucent Shoji paper: opaque

From the results of the visual evaluation and the results of the straight running rate shown in FIG. 4, the higher the straight running rate of the sample, the higher the transparency evaluated by visual observation, and the straight running rate is effective as an index of the transmission and scattering ability. Recognize.

[0031]

According to the straightness rate obtained by the method of the present invention, the transmission / scattering characteristic of the sample can be obtained as separated information separate from the absorption characteristic, and the straightness rate can be obtained by using a simple device. You can get it.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an apparatus of the present invention.

FIG. 2 is a relationship diagram of incident wavelength and transmittance for colorless frosted glass and brown frosted glass.

FIG. 3 is a relationship diagram between an incident wavelength and a straight traveling rate for colorless frosted glass and brown frosted glass.

FIG. 4 is a diagram showing the relationship between the incident wavelength and the straight advance rate for a transparent film for window glass, a blinding film for window glass, and shoji paper.

FIG. 5 is a schematic configuration diagram of a conventional measuring apparatus for transmission / scattering characteristics.

FIG. 6 is a schematic configuration diagram of a conventional detector angle variable type device.

[Explanation of symbols]

 1 sample 2 integrating sphere, 2h hole of integrating sphere 3 light source 4 detector 5 sample stage 6 base part

Claims (9)

[Claims] 1. A parallel light beam having a constant intensity is incident on a sample, and the amount of transmitted scattered light of the sample at that time is detected using an integrating sphere having a hole on the optical axis and a detector connected to the integrating sphere. In the method for measuring transmission and scattering power, the detected light amount I ₁ of transmitted and scattered light when the distance between the sample and the integrating sphere is d ₁ and the distance between the sample and the integrating sphere is d ₂ (however, d ₁ > d ₂ ), the ratio I ₁ / I ₂ of the transmitted scattered light to the detected light amount I ₂ is obtained as a straight traveling rate, and the transmission scattering ability of the sample is evaluated based on this straight traveling rate. Noh measurement method. 2. The straightness ratio I ₁ / I ₂ is defined as the detected light amount I ₁ when the distance between the sample and the integrating sphere is d ₁ and the detected light amount I ₂ when the sample and the integrating sphere are in close contact with _each other. The method for measuring transmission and scattering power according to claim 1, which is obtained as a ratio. 3. The transmission / scattering power measuring method according to claim 1, wherein parallel light having a predetermined wavelength is incident on the sample, and the rectilinear rate I ₁ / I ₂ of the detected light amount is obtained for each incident wavelength. 4. The method for measuring transmission and scattering power according to claim 1, wherein the hole of the integrating sphere is a perfect circle centered on the optical axis. 5. A light source capable of making parallel light of a constant intensity incident on a sample, an integrating sphere having a hole on the optical axis, and a detector connected to this integrating sphere to detect the amount of transmitted scattered light from the sample. And a sample holder for holding the sample in a variable position on the optical axis between the light source and the integrating sphere. 6. The transmission / scattering power measuring device according to claim 5, wherein the light source emits light of a predetermined wavelength. 7. The transmission / scattering power measuring device according to claim 5, wherein the hole of the integrating sphere is a perfect circle centered on the optical axis. 8. The amount of light I ₁ detected by the detector when the distance between the sample and the integrating sphere is d ₁ and the distance between the sample and the integrating sphere is d ₂ (where d ₁ > d ₂ ). 6. The transmission / scattering power measuring device according to claim 5, further comprising a calculating means for calculating a ratio I ₁ / I ₂ of the detector to the detected light amount I ₂ and an output means for outputting the calculation result. 9. A ratio I between the amount of light I ₁ detected by the detector when the distance between the sample and the integrating sphere is d ₁ and the amount of light I ₂ detected by the detector when the sample and the integrating sphere are brought into close contact with each other.
The transmission / scatterability measuring device according to claim 8, wherein ₁ / I ₂ is calculated as a straight traveling rate.