JP2014119286A - Method of evaluating translucency - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for evaluating translucency of an object with a higher degree of precision than the conventional method.SOLUTION: Ratios r/Iand r/Iof irradiation light quantity I,Ifor each of a first radiation area and a second radiation area to emission light quantity r,remitted by each of the first radiation area and the second radiation area are calculated, and translucency of an object is evaluated on the basis of difference of a value of 1-(r/I)/(r/I). Emission light quantity rand rat the time when light is irradiated on a reference white board is used as emission light quantity I,I. A board which has a reflectance ratio larger than 0.5 and has a region of 0.2 mm or smaller in thickness containing a light receiving surface is used as the reference white board.

Description

  The present invention relates to a method for evaluating translucency for the surface of an object.

  The applicant has so far made various proposals regarding a method of evaluating translucency for the surface of an object such as human skin (see, for example, Patent Documents 1 to 3). In these documents, the first irradiation region in the target part and the second irradiation region including the first irradiation region and wider than the first irradiation region are respectively irradiated with light, and the first irradiation is performed. Light emitted from the region and the second irradiation region is received. Then, the semi-transparency is evaluated by comparing the amount of light irradiated to each of the first irradiation region and the second irradiation region with the amount of light emitted from each of the first irradiation region and the second irradiation region. ing. In these documents, the evaluation of the object is referred to as “transparency”. However, in light of the principle of the method described in these documents, “transparency” means that light irradiated to an object It does not mean the degree of transmission, but means the degree of spread of the reflected light among the light irradiated to the object, that is, “translucency”.

JP 2004-305558 A JP 2006-102365 A JP 2010-14708 A

  By the way, in each of the above-mentioned documents, as the amount of light irradiated to each of the first irradiation area and the second irradiation area, instead of the actual object, when the light is irradiated to the common standard white plate attached to the apparatus The amount of emitted light was used. The regular standard white plate is originally used for calibration of the reflectance of the measurement object as a reference for the reflectance when measurement is performed in a predetermined irradiation region and measurement region. However, if the irradiation region and the measurement region change, the reflectance of the regular standard white plate itself changes due to the translucency of the regular standard white plate, and the reflectance of the measurement target cannot be calibrated correctly. As a result, in the method of measuring the reflectance under a plurality of irradiation areas, measurement areas, and calculating the values to evaluate the optical properties of the object, as in the translucency measurement in each document described above However, the standard is not set correctly. Therefore, the semi-transparency zero standard is not set correctly in the measurement of translucency. Furthermore, even when the semi-transparency value is obtained using the evaluation method described in each of the above-mentioned documents, and the absorption coefficient and effective scattering coefficient of the evaluation object are calculated based on the obtained translucency value. In some cases, there is a discrepancy between the calculated value and the actually measured value.

  Such a difference between the calculated value and the actually measured value can be resolved by using a semi-transparent substance as a reference. However, there is no material that can be easily obtained as a semi-transparent substance, and even if it is found, it is not easy to actually show that the semi-transparency is zero.

  Accordingly, an object of the present invention is to provide a translucency evaluation method in which the accuracy of evaluation is further improved as compared with the above-described prior art.

  The present inventor has diligently studied to solve the above-mentioned problem. Instead of the regular standard white plate, a material having a specific thickness and reflectance is used as a reference white plate, and the material is used as a semi-transparency = 0 standard. It has been found that the above problem can be solved by calibrating to the above.

That is, the present invention irradiates light to the first irradiation region in the object and the second irradiation region including the first irradiation region and wider than the first irradiation region,
Receiving the emitted light returning from each of the first irradiation region and the second irradiation region;
Irradiation light amounts I _S and I _L to the first irradiation region and the second irradiation region, respectively, and emission light amounts r _{S, S} , r _{S, L} emitted from the first irradiation region and the second irradiation region, respectively. R _{S, S} / I _S and r _{S, L} / I _L are calculated, and based on the magnitude of the translucency T _S expressed by the following formula (1), A semi-transparency evaluation method for evaluating translucency,
Translucency T _S = 1− (r _{S, S} / I _S ) / (r _{S, L} / I _L ) (1)
As each irradiation light quantity I _S , I _L , the emission light quantity r _{P, S} and r _{P, L} when the reference white plate is irradiated with light is used.
A semi-transparency evaluation method using a reference white plate having a reflectance of more than 0.5 and a thickness including a light receiving surface of 0.2 mm or less is provided.

  According to the present invention, it is possible to evaluate the translucency of an object with higher accuracy than the conventional methods. Therefore, the absorption coefficient and effective scattering coefficient of the object can be determined with higher accuracy than the conventional methods.

FIG. 1 is a diagram schematically showing one embodiment of the translucency evaluation apparatus of the present invention. FIG. 2A is a schematic diagram showing irradiation / light reception conditions in the first irradiation region in the translucency evaluation apparatus of the present invention, and FIG. 2B is an evaluation of translucency of the present invention. It is a schematic diagram which shows the irradiation and light reception conditions in the 2nd irradiation area | region in an apparatus. FIG. 3A is a schematic diagram showing an iris diaphragm as one embodiment of the diaphragm of the translucency evaluation apparatus of the present invention, and FIG. 3B is a diaphragm of the translucency evaluation apparatus of the present invention. It is a schematic diagram which shows the slide type aperture_diaphragm | restriction as one form. FIGS. 4A and 4B are schematic views showing the state of scattering of light incident on a reference white plate having different scattering properties. FIGS. 5A to 5D are schematic views showing how light incident on a reference white plate having different thicknesses is scattered. FIG. 6 is a schematic diagram illustrating a state of scattering of light incident on a reference white plate having a pointing portion. FIG. 7 is a diagram illustrating the coordinates of the point spread function. 8A and 8B are graphs showing the relationship between the effective scattering coefficient and absorption coefficient obtained in Example 1 and the pigment concentration. FIGS. 9A and 9B are graphs showing the relationship between the effective scattering coefficient and absorption coefficient obtained in Example 2 and the pigment concentration. 10A and 10B are graphs showing the relationship between the effective scattering coefficient and absorption coefficient obtained in Comparative Example 1 and the pigment concentration. FIGS. 11A and 11B are graphs showing the relationship between the effective scattering coefficient and absorption coefficient determined in Comparative Example 2 and the pigment concentration.

  The present invention will be described below based on preferred embodiments with reference to the drawings. FIG. 1 schematically shows an apparatus suitably used in the evaluation method of the present invention. In the figure, reference numeral 1 denotes an evaluation device. The evaluation apparatus 1 includes a measurement apparatus main body 2 and a computer system 3 connected to the measurement apparatus main body 2 via an input / output interface 20 via a cable 200.

  The measurement apparatus main body 2 irradiates light to an irradiation area A (see FIG. 2) to be described later via the integrating sphere 21 including the incident window 211, the irradiation window 212, and the light receiving window 213, and the incident window 211 and the irradiation window 212. A light source 22 that receives light emitted from the irradiation area A through the light receiving window 213, a diaphragm 24 that changes the irradiation area A and a measurement area M (see FIG. 2) described later, and computation. And a control unit 25.

  The integrating sphere 21 is one in which a white diffuse reflection paint such as MgO is applied to the inner wall. The integrating sphere 21 diffuses and reflects the light incident through the incident window 211, and a part of the light is irradiated onto the irradiation area of the measurement target section through the irradiation window 212, and the emitted light returning from the irradiation area is reflected on the integrating sphere 21. The light receiver 23 can receive light through the light receiving window 213. In the present embodiment, the incident window 211, the irradiation window 212, and the light receiving window 213 are emitted and received by an optical system of d / 8 ° (d is diffused light) as expressed in JIS Z8722 (irradiation angle / light reception angle). It is arranged to satisfy the conditions.

  There is no restriction | limiting in particular in the wavelength of the light which the light source 22 emits. In the case of making the measurement correspond to the appearance of the object, it is desirable that light including a visible light region (wavelength 360 to 740 nm) can be emitted. In order to align the dynamic range of each wavelength, those capable of emitting white light are desirable. For example, a xenon lamp is used as the light source 22. Further, when paying attention to a specific wavelength component, a spectroscope is interposed between the light source 22 and the incident window 211 so that light of the wavelength component can be incident. In the case of measuring skin coated with photochromic cosmetics, a light source capable of emitting light including ultraviolet light may be used.

  The light receiver 23 includes a spectroscopic lens, a spectroscope, and an array sensor in which a plurality of light receiving elements are arranged. The light receiver 23 splits the emitted light incident through the light receiving window 213 by the spectroscopic lens and introduces the light into the spectroscope, and outputs the value of the emitted light amount for each wavelength component of the array sensor to the arithmetic control unit 25. When measurement is performed by turning on a monochromatic light such as a light emitting diode as a light source or sequentially turning on a plurality of monochromatic lights, the light receiver does not have to include a spectroscope.

  FIGS. 2A and 2B are diagrams schematically showing irradiation / light reception conditions of irradiation light and emission light of the optical system in the measurement apparatus main body 2. The diaphragm 24 changes the irradiation area by changing the size of the opening 240. Further, the light receiving area can be changed by changing the size of the light receiving window 213. When the light receiving area M is larger than the irradiation area A, the entire irradiation area becomes the measurement area. In this case, a portion of the light receiving region M that is not included in the irradiation region (= measurement region) A is made of a black material having a low reflectance on the inner surface of the diaphragm 24 in order to suppress reflection from the portion. Is preferred. The diaphragm 24 has a so-called iris diaphragm (lens diaphragm mechanism employed in a camera or the like) that rotates the knob 24a to change the irradiation area, as shown in FIG. It is preferable to use a slide diaphragm that slides the plate to change the irradiation area. Alternatively, the diaphragm 24 may be one that attaches and detaches a plurality of diaphragm members with different sizes of the opening 240.

  The arithmetic control unit 25 shown in FIG. 1 includes a so-called microcomputer unit, and includes an arithmetic processing unit (CPU), a main storage device, a trigger device, and a bus connecting these devices. A program is stored in the main storage device. When the arithmetic control unit 25 receives a trigger signal from the trigger device in a state where the program is activated, the arithmetic control unit 25 captures and holds the emission light amount of each wavelength output from the array sensor in the main storage device. Then, as will be described later, it functions to transmit the emitted light quantity held in accordance with a command from the computer system 3 to the main body 31 in a predetermined format.

  The computer system 3 includes a main body 31, an input device 32, and an output device 33. The input device 32 and the output device 33 are connected to the main body 31 via an interface (not shown). In this embodiment, the main body 31 functions as an evaluation processing unit, and the output device 33 functions as an evaluation result output unit.

  The main body 31 includes an arithmetic processing unit (CPU), a main storage device (RAM), an auxiliary (external) storage device, an interface for connecting the input device and the output device, and a bus connecting them. . In the main storage device or the auxiliary storage device, a program for taking in the amount of emitted light from the measuring device main body 2 and evaluating it is stored. In a state where this program is activated, the main body 31 functions as an evaluation processing unit that evaluates translucency.

  In the evaluation method of the present embodiment, when light is irradiated onto a translucent object that is an object to be evaluated, the fact that the reflectance changes when the area of the irradiation region changes is used. Specifically, it utilizes that the amount of change in reflectance reflects the translucency of the object. The specific evaluation procedure is as follows.

As shown in FIGS. 2A and 2B, the first irradiation area A1 and the second irradiation area including the first irradiation area A1 in the evaluation target part and wider than the first irradiation area A1. A2 is irradiated with light from the light source 22, respectively. Then, light emitted from the first irradiation area A1 and the second irradiation area A2 is received by the light receiver 23. Further, the irradiation light amounts I _S and I _L to the first irradiation area A1 and the second irradiation area A2, respectively, are measured, and the respective emission emitted from the first irradiation area A1 and the second irradiation area A2. The light amounts r _{S, S} , r _{S, L} are measured. Therefore, the reflectance in the first irradiation area A1 is represented by r _{S, S} / I _S. On the other hand, the reflectivity at the second irradiation area A2 is expressed by r _{S, L} / I _L.

In the present embodiment, the light emission amounts I _S and I _L to the first irradiation area A1 and the second irradiation area A2 are emitted when light is irradiated on the reference white plate instead of the object to be evaluated. The light amounts r _{P, S} and r _{P, L} are used.

  In addition, what is necessary is just to change the magnitude | size of the opening part of the aperture_diaphragm | restriction 24, when changing an irradiation area | region. At this time, it is preferable that the irradiation region A1 is included in the light receiving region M and A2 includes the light receiving region M. A portion of the light receiving region M that is not included in the irradiation region is preferably made of a black material having a low reflectance in order to suppress reflection from the portion.

The value of r _{S, S} / I _S that is the reflectance in the first irradiation region A1 and the value of r _{S, L} / I _L that is the reflectance in the second irradiation region A2 are used, and in this embodiment, it is translucent. The property T _S can be defined by the following equation (1).
Translucency T _S = 1− (r _{S, S} / I _S ) / (r _{S, L} / I _L ) (1)
As is clear from this equation, the value of the translucency T _S takes a value from 0 to 1.

In Expression (1), as I _S and I _L, as described above, the amounts of emitted light r _{P, S} and r _{P, L} when the reference white plate is irradiated with light are used. r _{P, S} is the amount of light emitted when the reference white plate is irradiated with light in the first irradiation area A1. r _{P, L} is the amount of light emitted when light is irradiated on the same reference white plate in the second irradiation area A2. When these r _{P, S} and r _{P, L} are used, the formula (1) can be expressed as the following formula (1 ′).
Translucency T _S = 1− (r _{S, S} / r _{P, S} ) / (r _{S, L} / r _{P, L} ) (1 ′)
Here, in order to obtain the reflectances at A1 and A2, it is necessary to correctly divide r _{P, S} and r _{P, L} by the reflectance of the reference white plate, but the translucency calculation is used for each ratio. This operation can be omitted.

In the present embodiment, when calculating the translucency T _S from said formula (1 '), a semi-transparent material is used as a reference white plate is advantageously calibrated so that 0. The details of this calibration are as follows.

When the reflectance in the first irradiation area A1 is expressed as R _{S, S} and the reflectance in the second irradiation area A2 is expressed as R _{S, L} , R _{S, S} and R _{S, L} are expressed by the following equations. It is defined as (2) and (3).

Using the above formulas (2) and (3), the target translucency T _S is expressed by the following formula (1 ″).

The technical meanings of the above formulas (2) and (3) are as follows. In equations (2) and (3), r _{B, S} and r _{B, L} are correction terms for correcting reflection from a region not included in the irradiation region. This correction term represents the amount of light emitted when the first irradiation region A1 and the second irradiation region A2 are irradiated with light in a state where there is no target. These corrected emission light amounts r _{B, S} and r _{B, L} are subtracted from the emission light amounts r _{S, S} , r _{S, L} and the emission light amounts r _{P, S} , r _{P, L} to correct the value of each emission light amount. Thus, the value of each irradiation light quantity can be brought close to an actual value. As a result, the evaluation can be performed with higher accuracy.

Also, in the formulas (2) and (3), the reason for multiplying the term (r _{P, L} −r _{B, L} ) is that when the translucency is measured for a reference white plate, the translucency This is because when the value is 0 and the reflectance of the reference white plate is measured, the reflectance is calibrated to be the reflectance of the reference white plate (in the normal measurement). By performing such calibration, the translucency value of the reference white plate with the semi-transparency = 0 reference becomes 0, and the reflectance of the reference white plate with the semi-transparency = 0 reference becomes r _{P, L} That is, the reflectance of the reference white plate in the second irradiation area A2 is obtained. If calibration is performed correctly, r _{B, L} = 0.

  As the reference white plate used in the present embodiment, it is preferable to use a semi-transparency that is as close to 0 as possible from the viewpoint of improving the accuracy of evaluation. A translucency of 0 means that all of the irradiated light returning from the reflection returns from the incident point. The return position is important and it is not required that all irradiated light be returned. In order to make the translucency as close to 0 as possible, it is desirable that the reference white plate has (a) a high scattering property and (b) is thin. This will be described with reference to FIGS.

  4A and 4B show light scattering states in two reference white plates W having different scattering properties. Among these figures, in FIG. 4A, it can be seen that the position from which the emitted light R is emitted is far from the position of the irradiated light I, and the emitted light is spread laterally. On the other hand, in FIG. 4B, the emission light R is emitted from a position near the position of the irradiation light I. Therefore, FIG. 4B is more highly scattered and preferable than FIG. 4A.

  FIGS. 5A to 5D show light scattering states in four reference white plates W having different thicknesses. It is assumed that the four reference white plates W shown in these drawings have the same degree of scattering. As is clear from these figures, when the scattering property of the reference white plate W is the same, as the thickness of the reference white plate W becomes thinner, the light that spreads to the side becomes easier to pass through the reference white plate W. The emitted light R that spreads laterally and exits is reduced. As a result, the thinner the reference white plate W is, the more the emission light R is emitted from the position near the position of the irradiation light I. Therefore, in order to bring the translucency closer to 0, FIG. 5B is preferable to FIG. 5A, FIG. 5C is more preferable than FIG. 5B, and FIG. FIG. 5D is preferable to c). However, if the thickness of the reference white plate W is reduced, the amount of the emitted light R is reduced, so that the measurement sensitivity tends to decrease. Therefore, it is preferable that the thickness of the reference white plate W is thin and the reflectance is high.

  In consideration of the above, it is advantageous to use a reference white plate having a reflectance of more than 0.5, preferably 0.6 or more, more preferably 0.65 or more as the reference white plate used in the present embodiment. As a result of the study by the present inventor, it has become clear. In addition, it is advantageous that the thickness of the portion including the light receiving surface as the reference white plate is 0.2 mm or less, preferably 0.15 mm or less, more preferably 0.1 mm or less. It became clear as a result of examination. There is no particular limitation on the upper limit value of the reflectance, and the closer the value is to 1, the better. Similarly, there is no particular limitation on the lower limit value of the thickness. The thinner the thickness, the better (for example, 0.01 mm). The lower limit of the upper limit value is about 0.15 mm, and the object of the present invention is sufficiently achieved. In particular, in consideration of the operability used for the measurement, it is preferable that some reinforcement is performed in the case of 0.05 mm or less. Moreover, it is preferable that a reference | standard white board does not contain the fluorescent agent which emits the light of the wavelength range to be used.

  The reflectance of the reference white plate is a value obtained by using the apparatus shown in FIGS. 1 and 2 and irradiating the target white plate with light. It is preferable that the wavelength of the irradiated light has the same spectrum as the light irradiated to the target object to be evaluated.

  Examples of a preferable reference white plate that satisfies the above-described conditions include various white papers. Specifically, it is preferable to use PPC paper (copy paper plain paper) because it is simple and economical. Commercially available PPC paper may be used. When PPC paper is used as the reference white plate, the basis weight is not particularly limited as long as the thickness and the reflectance satisfy the above values.

  If the thickness of the reference white plate is reduced, the rigidity may be reduced depending on the material, and it may be difficult to handle by itself. In such a case, as shown in FIG. 6, as the reference white plate W, a white thin layer portion 41 including the light receiving surface 40 and having a thickness of 0.2 mm or less is adjacent to the thin layer portion 41. It is advantageous to use one having a support portion 42 located on the opposite side of the light receiving surface 40. The reference white plate W preferably has a reflectance measured from the light receiving surface 40 side of more than 0.5.

  When the reference white plate W shown in FIG. 6 is used, when the thickness of the thin layer portion 41 is reduced, the amount of light transmitted through the thin layer portion 41 in the irradiation light I is increased. At this time, if the light transmitted through the thin layer portion 41 is scattered in the support portion 42 and is incident on the thin layer portion 41 again, the emission light R is emitted in a state of spreading laterally. Therefore, the reference white plate W does not become low translucent. Therefore, when the reference white plate W shown in FIG. 6 is used, it is preferable to use a material that does not allow the light transmitted through the thin layer portion 41 to enter the thin layer portion 41 again as the support portion 42. As the support portion 42, it is preferable to use a cardboard having a low reflectance. As a specific example of the reference white board W, a sheet in which a white paper as the thin layer portion 41 is attached to a thick board such as a cardboard (so-called white cardboard) can be used. Commercially available white cardboard may be used.

  In the present embodiment, the area ratio (A1 / A2) between the first irradiation region A1 and the second irradiation region A2 is preferably 0.05 or more, and more preferably 0.1 or more. The upper limit is preferably 0.5 or less, and more preferably 0.3 or less. For example, the area ratio A1 / A2 is preferably 0.05 or more and 0.5 or less, and more preferably 0.1 or more and 0.3 or less. By setting the area ratio A1 / A2 within this range, the amount of received light in the measurement of the first irradiation area A1 is secured to some extent, and the measurement of the first irradiation area A1 and the measurement of the second irradiation area A2 are performed. Difference in the amount of received light and the semi-transparency can be evaluated with higher accuracy.

The area ratio between the first irradiation region A1 and the second irradiation region A2 is as described above. The area of the first irradiation region A1 itself is preferably 5 mm ² or more, and more preferably 7 mm ² or more. More preferably. The upper limit of the area is preferably 40 mm ² or less, and more preferably 20 mm ² or less. For example the area of the first irradiation area is preferably 5 to 40 mm ^2, further preferably 7~20mm ^2. On the other hand, the area of the second irradiation region A2 itself is preferably 30 mm ² or more, and more preferably 60 mm ² or more. The upper limit value of the area is preferably 250 mm ² or less, and more preferably 150 mm ² or less. For example the area of the second irradiation area is preferably 30～250Mm ^2, and further preferably from 60～150Mm ^2. By setting the area of each irradiation region A1, A2 within this range, it becomes easier to closely contact the diaphragm with the object. In addition, the amount of wraparound light with respect to the amount of received light can be detected more accurately. As a result, the translucency of the object can be evaluated with higher accuracy.

  There is no restriction | limiting in particular in the shape of 1st irradiation area | region A1. In general, a circular shape is preferred. The shape of the second irradiation area A2 is preferably concentric with the first irradiation area A1.

  As described above, the translucency of the object can be accurately evaluated. Examples of the object to be evaluated include human skin, teeth, silicone resin, prosthesis and the like. When targeting human skin, there is no particular limitation on the target part, and for example, each part of the human body including the face, hands and feet can be evaluated, and makeup skin is not limited to bare skin. It can also be.

  In the present embodiment, the absorption coefficient and the effective scattering coefficient of the object can be obtained using the translucency value of the object obtained by the evaluation method of the present embodiment. This procedure will be described below.

It is known that the point spread function I (r) shown in FIG. 7 has the following relationship with the absorption coefficient μ _a and the effective scattering coefficient μ _s ′ (for example, Medical Physics 19 (4) 879-888). In the equation, r is a distance from the incident point, and I (r) is a reflection intensity distribution.

The point spread function I (r) and the above-described R _{S, S} , R _{S, L} and T _S have the following relationship (see, for example, Journal of Biomedical Optics 16 (11) 117003). about.).

Using the above equation, the absorption coefficient μ _a and the effective scattering coefficient μ _s ′ can be solved by numerical calculation from R _{S, L} and T _S obtained by measurement.

Based on the values of the absorption coefficient μ _a and the effective scattering coefficient μ _s ′ obtained by the method as described above, it is possible to know the degree of light absorption and scattering for the evaluation object. Then, based on these values and the previously obtained value of translucency T _S , when the object is human skin, for example, it is possible to objectively evaluate the so-called “skin transparency”. . It can also be applied to the evaluation of “skin transparency” of skin, makeup skin, tanned skin and the like after use of various beauty creams.

As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, in the embodiment, when calculating the reflectance R _{S, S} in the first irradiation area A1 and the reflectance R _{S, L} in the second irradiation area A2, from the area not included in the irradiation area Although r _{B, S} and r _{B, L} which are correction terms for correcting reflection of the light are introduced, the reflectances R _{S, S} and R _{S, L} can be calculated without introducing these correction terms. good. In this case, the expressions (2) and (3) are represented by the following expressions (2 ′) and (3 ′).

  Further, for the purpose of further improving the accuracy of the evaluation, the operation of light irradiation and light reception of the emitted light is alternately performed a plurality of times for both irradiation areas A1 and A2, and the comparison between the irradiation light quantity and the emitted light quantity is performed. You may perform about the operation of each time in multiple times. Details of such an operation are described in JP-A-2006-102365.

  For the same purpose, the area ratio of the measurement region of the emitted light from the second irradiation region A2 to the second irradiation region A2 (the area of the measurement region / the area of the irradiation region) is set to the first irradiation region A1. You may make it small compared with the area ratio (area of a measurement area / area of an irradiation area | region) of the measurement area | region of the emitted light from 1st irradiation area | region A1. Details of such an operation are described in Japanese Patent Laid-Open No. 2010-14708.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples.

[Example 1]
Using the following measuring apparatus main body, the irradiation amount was measured five times for each of the following reference white plate and the following evaluation object by changing the aperture and changing the irradiation area as described below. White light was used as the light source. Next, in a commercially available personal computer system connected to the apparatus main body, the color management software “CM-S9w” for the spectral colorimeter CM series is started, and the measured emission light amount is transferred from the measuring apparatus to the computer system in the CSV format. I took it in. Then, after statistically processing these emitted light quantities on a commercially available spreadsheet (“Excel” manufactured by Microsoft Corporation in the United States), the reflectivity R _{S, S} and the above-described formulas (2) and (3) are used. R _{S, L} was determined, and further translucency T _S was determined. Based on the calculated values of R _{S, L and} T _S , the absorption coefficient μ _a and the effective scattering coefficient μ _s ′ were calculated by numerical calculation (here, “MATLAB” manufactured by Massworks, USA) was used as software. . The result is shown in FIG.

<Measurement conditions>
Main unit: manufactured by Minolta Co., Ltd., spectral colorimeter “CM-2600d”
Irradiation / light reception conditions: d / 8 ° (JIS Z8722)
Irradiation area A1: Circular shape with a diameter of 4 mm Irradiation area A2: Circular shape with a diameter of 11 mm substantially concentric with the irradiation area A1 Reference white plate: PPC paper (thickness 0.091 mm, reflectance 0.69 (wavelength 550 nm) under a D65 light source) L * = 86.8, a * = − 0.143, b * = − 0.333)
Measurement: Measurement was performed 5 times for each sample and each measurement region 5 times.
Interval of each measurement: about 10 seconds Evaluation object: 4 types of silicone samples (transparent room temperature curable silicone and pigment (mixture of titanium oxide, iron oxide, etc.) at 5 different concentrations (0.10, 0.15, 0.20, 0.50 mass%) and kneaded and cured)

[Example 2]
As a reference white plate, 0.081 mm thick white paper is used and 0.492 mm thick cardboard (L * = 91.73, a * = 0.012, b * = 1.492 under D65 light source) The one pasted on (white ball) was used. The reflectance of this reference white plate measured from the white paper side was 0.80 (wavelength 550 nm). Other than this, the values of R _{S, S} and R _{S, L and} T _S were determined in the same manner as in Example 1, and the absorption coefficient μ _a and the effective scattering coefficient μ _s ′ were determined from these values by numerical calculation. The result is shown in FIG.

[Comparative Example 1]
As a reference white plate, a plastic plate (ordinary standard white plate) attached to the spectrocolorimeter “CM-2600d” was used. This plastic plate was a standard white plate, having a thickness of 5 mm and a reflectance of 0.93 (wavelength 550 nm). Other than this, the values of R _{S, S} and R _{S, L and} T _S were determined in the same manner as in Example 1, and the absorption coefficient μ _a and the effective scattering coefficient μ _s ′ were determined from these values by numerical calculation. The result is shown in FIG.

[Comparative Example 2]
Tracing paper was used as the reference white plate. The tracing paper had a thickness of 0.04 mm and a reflectance of 0.24 (wavelength 550 nm). Other than this, the values of R _{S, S} and R _{S, L and} T _S were determined in the same manner as in Example 1, and the absorption coefficient μ _a and the effective scattering coefficient μ _s ′ were determined from these values by numerical calculation. The result is shown in FIG.

As is apparent from the results shown in FIG. 8 to FIG. 11, the values of the absorption coefficient μ _a and the effective scattering coefficient μ _s ′ obtained in each example have different correlation coefficients with the concentration of the pigment added to the silicone resin. It turns out that it is higher than a comparative example. Therefore, by adopting the method of the present invention, it is possible to accurately predict the values of the absorption coefficient μ _a and the effective scattering coefficient μ _s ′.

DESCRIPTION OF SYMBOLS 1 Semitransparency evaluation apparatus 2 Measuring apparatus main body 20 Input / output interface 200 Cable 211 Incident window 212 Irradiation window 213 Light receiving window 21 Integrating sphere 22 Light source 23 Light receiver 24 Aperture 25 Operation control part 3 Computer system 31 Main body (Evaluation processing part)
32 Input device 33 Output device 40 Light receiving surface 41 Thin layer portion 42 Support portion A Irradiation region M Light reception region I Irradiation light R Emission light W Reference white plate

Claims (6)

Irradiating light to each of a first irradiation region and a second irradiation region that includes the first irradiation region and is wider than the first irradiation region;
Receiving the emitted light returning from each of the first irradiation region and the second irradiation region;
Irradiation light amounts I _S and I _L to the first irradiation region and the second irradiation region, respectively, and emission light amounts r _{S, S} , r _{S, L} emitted from the first irradiation region and the second irradiation region, respectively. R _{S, S} / I _S and r _{S, L} / I _L are calculated, and based on the magnitude of the translucency T _S expressed by the following formula (1), A semi-transparency evaluation method for evaluating translucency,
Translucency T _S = 1− (r _{S, S} / I _S ) / (r _{S, L} / I _L ) (1)
Using the emitted light amounts r _{P, S} and r _{P, L} when the light is irradiated on the reference white plate as the target light amounts I _S , I _L ,
A semi-transparency evaluation method using a reference white plate having a reflectance of more than 0.5 and a thickness including a light receiving surface of 0.2 mm or less.   When the translucency of the reference white plate is measured, it becomes 0, and when the reflectivity of the reference white plate is measured, the calibration of the formula (1) is performed so that the reflectivity of the reference white plate in the second irradiation area A2 is obtained. The evaluation method according to claim 1 to be performed.   The evaluation method according to claim 1, wherein PPC paper is used as the reference white plate.   A reference white plate having a thin layer portion including the light receiving surface and having a thickness of 0.15 mm or less, and a support portion located adjacent to the thin layer portion and opposite to the light receiving surface. The evaluation method according to claim 1 or 2 to be used.   The evaluation method according to claim 4, wherein a white ball is used as the reference white plate. Separately from the measurement of the emitted light amount r _{S, S} , r _{S, L} and the emitted light amount r _{P, S} , r _{P, L} , the first irradiated region and the second irradiated region are corrected and emitted without the object. The light amounts r _{B, S} , r _{B, L} are measured, and the emitted light amounts r _{S, S} , r _{S, L} and the emitted light amounts r _{P, S} , r _{P, L} are corrected as the corrected emitted light amounts r _{B, S} , r _{B. , L} is used to calculate translucency from the following equation corrected by _L.