KR20200048364A - Method for Evaluating Improvement Ability of Skin Tone and Method for Screening Improvement Active Materials of Skin Tone - Google Patents

Abstract

The present invention relates to a method for evaluating skin tone improvement efficacy and a screening method of materials having skin tone improvement activity. According to the present invention, provided are an accurate evaluation method and screening method capable of improving a cognitive skin tone compared to a conventional measurement method which does not conform to a consumer trend by using a new evaluation index which is highly correlated with the cognitive skin tone which a consumer actually sees and feels.

Description

Method for Evaluating Improvement Ability of Skin Tone and Method for Screening Improvement Active Materials of Skin Tone}

The present invention relates to a method for evaluating skin tone improving efficacy and a method for screening a substance having skin tone improving activity, and more specifically, comprising calculating a new evaluation index highly correlated with cognitive skin tone actually seen and felt by a consumer. It relates to a method for evaluating skin tone improving efficacy and a method for screening a substance having skin tone improving activity.

In the era of low growth, the competition of beauty-related companies is becoming more intense, and consumers' sensitivity and sensitivity are becoming more diverse. The representative product group that most sensitively reflects this market trend is base makeup products related to skin tone expression. If you look at the consumer trends of related products, it is analyzed that you prefer products that reproduce skin tones that are more suitable for you, and recently conducted a survey (Korea Cosmetics Industry Research Institute, In-depth Survey of Foreign Cosmetic Consumers, 2014, pp. 24 ~ 411) According to the results, regardless of nationality or race, light skin tones are preferred.

Evaluating the efficacy of a product (eg, artificial synthetic compound, natural extract, etc.) or product that exhibits or is expected to exhibit a skin tone improvement effect capable of realizing a light skin tone by reflecting the consumer's product preference is a skin tone improvement functionality It is also considered important in the research and development process of cosmetics. In order to provide objective information about skin tones, it is generally used to analyze and evaluate skin tones by measuring the brightness and saturation of skin tones using a colorimeter.

In order to secure the objectivity of analyzing and evaluating skin tone using a colorimeter, Korean Patent Publication No. 10-2011-0082227 also provides a method for evaluating skin tone grades using a colorimeter to substantially reflect a subject's condition. . However, the above method of evaluating a subject's skin tone grade based only on the measured skin tone still has a problem that the skin tone preferred by the consumer is not properly reflected.

There is a difference between the perceived skin tone that consumers actually see and feel and the actual skin tone measured using a colorimeter. Therefore, not only the actual skin tone, but also the actual skin tone and cognitive skin tone are reflected to develop cosmetics, especially functional and color cosmetics for skin tone improvement, and development of technology to guide makeup based on the product developed to consumers. This is a demand.

Republic of Korea Patent Publication No. 10-2011-0082227

The present invention has been devised to solve the above problems, and the object of the present invention is to provide a new evaluation index that can reflect the preference for cognitive skin tone while having high correlation with cognitive skin tone that consumers actually see and feel. will be. In addition, the present invention provides an accurate efficacy evaluation method and screening method for a cosmetic material and / or product having functionality capable of actually improving skin tone while meeting the trend of skin tone preference of consumers using this new evaluation index. will be. Therefore, the present invention is useful for verifying the efficacy of skin tone improving substances and products, and is very useful in developing functional or color cosmetics that properly and immediately reflect the cognitive skin tone trend preferred by consumers.

As a result of earnest research by the present inventors to achieve the above object, the ratio (S) of the reflectance (S) measured in the violet, blue, or violet to blue wavelength region relative to the reflectance (Rt) measured in the entire visible light wavelength region (S / Rt) was found to have a significant correlation with the cognitive skin tone that the subject actually sees and feels, and the present invention provides visible light for (a) before and after applying the test substance to a predetermined area of the subject's skin. Measuring the reflectance in the wavelength range and storing the measured value, (b) processing the measured value stored in the step (a) in the calculation unit set in Equation 1 below, and the skin tone index (T _b ) before application of the test substance and Skin comprising the step of calculating the skin tone index (T _a ) after application and (c) outputting the skin tone index increase rate (T _a -T _b ) * 100 / T _b before and after application of the test substance. Tone improvement efficacy It provides a screening method of a substance having a skin-tone method and improved activity.

(T: skin tone index,

S: reflectance measured in the violet, blue, or violet to blue wavelength range,

Rt: reflectance measured over the entire visible wavelength range).

According to the present invention, by using a new skin tone evaluation index that is highly correlated with the perceived skin tone actually seen and felt by the consumer, it is possible to replace the conventional measurement method that does not conform to the consumer makeup trend. In addition, according to the present invention, it is possible to provide an active substance capable of improving skin tone and a cosmetic using the same by objectively reflecting the correlation between the measured skin tone and the perceived skin tone. According to the present invention, a method and screening method for accurately evaluating the efficacy of a cosmetic material and / or product having functionality capable of actually improving the skin tone while reflecting the skin tone preferred by the consumer and in line with the market trend and makeup trend Can provide.

1 is a flow chart of a method according to an embodiment of the present invention.
2 is a flowchart of a method according to another embodiment of the present invention.
FIG. 3 is a diagram showing a correlation analysis result between analysis indexes including an analysis index and cognitive skin tone according to an embodiment of the present invention.
4 is a view showing the results of correlation analysis between cognitive skin tone and skin reflection spectrum according to an embodiment of the present invention.
5 is a diagram showing the results of a correlation analysis between a cognitive skin tone according to an embodiment of the present invention and a skin tone index as an index according to the present invention.

Hereinafter, the present invention will be described in detail with reference to examples and drawings.

In the present invention, the term 'cognitive skin tone' refers to the overall skin color, brightness, and condition that a subject actually sees and feels in a makeup or non-make-up state (e.g., uniformity, presence or absence of skin problems such as acne, rashes, blotch, etc.) Meaning, in one embodiment of the present invention, the subject's cognitive skin tone-related information may be obtained by an expert's questionnaire for the subject and a subject's self-question. Expert interviews and subject self-questions are not required to be performed, and any one of these methods can be used to obtain subject's skin tone related information.

In the present invention, the material to be tested means a substance having or presumed to have skin tone improvement efficacy, unless otherwise defined, and this substance is used as a main component of a functional cosmetic composition for improving skin tone, or of other main components. It can also be used as an auxiliary ingredient to improve the skin tone improving function.

1 is a flowchart illustrating a method for evaluating skin tone improvement efficacy or a method for screening a substance having skin tone improving activity according to an embodiment of the present invention. As shown in FIG. 1, a method for evaluating skin tone improving efficacy or a method for screening a substance having skin tone improving activity according to an embodiment of the present invention includes: (a) applying a substance to be tested to a predetermined area of the subject's skin For each of the before and after, measuring the reflectance in the visible light wavelength range and storing the measured values (S100), (b) processing the measured values stored in the above step (a) in the calculation unit with the following equation 1 set to test Steps (S200) and (c) of calculating the skin tone index (T _b ) before application of the target substance and the skin tone index (T _a ) after application (T _a -T _b) ) * 100 / T _{b It} is characterized in that the configuration comprises a step (S300) for output.

In step (S100) of the present invention, before and after applying the test substance to a predetermined area of the subject's skin, the reflectance is measured in the visible light wavelength range to store the measured value.

In the present invention, the reflectance is measured in the visible light wavelength region, which is a region of light that can be perceived by the human eye in order to objectively reflect the perceived skin tone that a consumer actually sees and feels. Specifically, the visible light wavelength region may be a wavelength region of 400 to 700 nm. A halogen lamp, a xenon lamp, a deuterium lamp or a white light emitting diode is used as the light source emitting the visible light, but is not limited thereto.

The visible light emitted from the light source is reflected in a predetermined area of the subject's skin, and the visible light spectrometer receives the reflected light and spectralizes the received light to output a reflectance as a function of a function of wavelength or frequency. The visible light spectrometer includes a light-receiving unit such as a photodiode, a phototransistor, or an electronic coupling element, and may include the light source.

In the step (b) of the present invention (S200), the measured value stored in the step (S) of (a) is processed by the calculation unit in which Equation 1 below is set, and the skin tone index (T _b ) before application of the test substance and skin after application Calculate the tone index (T _a ).

[Equation 1]

(T: skin tone index,

S: reflectance measured in the violet, blue, or violet to blue wavelength range,

Rt: reflectance measured over the entire visible wavelength range).

In general, the perceived brightness and measured brightness of the skin are related to the entire spectrum of light reflected from the light source, and the present inventors found that there is a significant correlation between the cognitive skin tone and the spectrum of the wavelength range of 400 to 490 nm. . Therefore, in Equation 1, the purple region is 400 to 455 nm, the blue region is 455 to 490 nm, and the purple to blue wavelength region is preferably a wavelength region of 400 to 490 nm. In particular, the present inventors have found that there is a significant correlation between the reflectance measured in a continuous region of the entire purple-blue wavelength and the perceived skin tone of the subject, and accordingly, compared to the respective regions of purple or blue, the purple-blue wavelength It is preferable to use the entire continuous area. When each region of the purple or blue is used instead of the continuous region of the purple to blue wavelength, the purple region is preferably 400 to 450 nm, and the blue region is more preferably 460 to 490 nm.

In step (c) (S300), the skin tone index increase rate (T _a -T _b ) * 100 / T _b before and after application of the test substance is output.

As shown in Figure 2, the skin tone improvement efficacy evaluation method according to another embodiment of the present invention or a screening method of a material having a skin tone improving activity, the step (c) (S300) before application of the test substance, When the skin tone index increase rate (T _a -T _b ) * 100 / T _b is 1.03% or more after, it may be determined as having skin tone improvement efficacy and outputting the determination result (S310). The reference value of 1.03% corresponds to a lower limit derived when calculating with a 95% confidence interval in the embodiment of the present invention. The skin tone improvement efficacy evaluation result may be output in a visual or audible manner, and if the device is capable of outputting a skin tone improvement efficacy evaluation result or a screening result of a substance having skin tone improvement activity in this manner, the output unit is not limited. Can be implemented as

{Example}

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are provided by way of example only to help understanding of the present invention, and the contents of the present invention are not limited to the following examples.

<Reference Example 1> Correlation analysis between cognitive skin tone and actual skin tone

1. Survey of cognitive skin tone through survey

61 healthy Korean women with an average age of 33.8 ± 7.8 years were selected as subjects. The questionnaire was conducted in the form of self-response, and among the three questions, '1) bright, 2) red, and 3) yellow, the skin tone was checked by checking the items I think.

2. Measurement of actual skin tone using a spectrophotometer

Before measurement, the faces of all subjects were washed with cleansing foam (Foam) and then waited for 15 minutes in constant temperature and humidity conditions (22 ± 2 ° C, 45 ± 5% RH).

Skin color was measured using a spectrophotometer (Spectrophotometer, CM2600d, Minolta, Japan), and the blank value of the spectrophotometer was corrected to 0 and 99 before measurement to start measurement. Measure the front cheek area using a spectrophotometer to determine the skin brightness (lightness, L * parameter values), skin redness (a * parameter values) and skin yellowness (b * parameter values). I got it.

Significant correlation was analyzed using a statistical analysis program (ANOVA (SPSS 20.0)) after measuring skin tone.

3. Correlation analysis result between cognitive skin tone and actual skin tone

The results of correlation analysis between cognitive skin tone and actual skin tone are shown in Table 1 below.

division Actual skin tone L * parameter value a * parameter value b * parameter value Cognitive skin tone bright Correlation coefficient 0.383 -0.169 -0.424 p-value 0.002 0.194 0.001 Red Correlation coefficient -0.455 0.619 -0.462 p-value 0.000 0.000 0.000 Yellow Correlation coefficient -0.076 -0.156 0.689 p-value 0.560 0.231 0.000

From Table 1, when the subjects themselves perceived the skin to be bright, the L * parameter value was found to have a significant correlation with a correlation coefficient of 0.383, and the b * parameter value was also found to have a significant correlation with a correlation coefficient of -0.424.

<Reference Example 2> Derivation of indicators that are significantly correlated with cognitive skin tone

From the analysis results of Reference Example 1, which was found to have a significant correlation between the L * parameter value and the b * parameter value and cognitive skin tone, the following experiment was performed to derive an index having a higher correlation with cognitive skin tone .

1. Derivation of indicators expected to correlate with cognitive skin tone

The spectrum of the skin brightness value (lightness, L * parameter value), skin redness value (aness, a * parameter value), skin yellowness value (yellowness, b * parameter value) and reflected light measured in Reference Example 1 alone or In combination, we derived an index that is expected to correlate with the perceived skin tone that the subject actually saw and felt, and then analyzed the actual correlation. Significant correlation was analyzed using ANOVA (SPSS 20.0) after skin tone measurement.

The results of the correlation analysis between the cognitive skin tone and the measured value derived from Reference Example 1 and the spectrum of reflected light alone or in combination are shown in FIG. 3 below.

2. Results of deriving indicators that have a significant correlation with cognitive skin tone

As shown in FIG. 3, the reflectance (Rt) measured in the entire visible light wavelength region, in particular, the skin tone index (T), which is the ratio occupied by the reflectance measured in the purple or blue wavelength region, has a correlation coefficient of 0.56, 0.51. , Showed a significant correlation.

<Reference Example 3> Correlation analysis between cognitive skin tone and skin reflection spectrum 1

The analysis result of Reference Example 2, which shows a significant correlation between the skin tone index (T) and the perceived skin tone, which is the ratio of the reflectance measured in the violet or blue wavelength region among the reflectance (Rt) measured in the entire visible light wavelength region In order to compare in more detail, the following experiment was performed.

1. Measurement of actual skin tone using a spectrometer

Before measurement, the faces of all subjects were washed with cleansing foam (Foam) and then waited for 15 minutes in constant temperature and humidity conditions (22 ± 2 ° C, 45 ± 5% RH). The skin reflection spectrum was measured using a spectrometer (CM-2600d, Konica Minolta), the optical resolution of the used spectrometer is 0.01%, and the measurable wavelength range is 360-740 nm. The spectrum of the reflected light was obtained by measuring the front cheek area using a spectrometer. Significant correlation was analyzed using ANOVA (SPSS One-way) after skin tone measurement. The results of correlation analysis between cognitive skin tone and actual skin tone are shown in FIG. 4 below.

2. Correlation analysis result between cognitive skin tone and skin reflection spectrum

As shown in FIG. 4, it was shown that there was a significant correlation between the reflectance measured in the continuous region of the entire purple to blue wavelength and the perceived skin tone of the subject. Among the continuous regions of the entire purple to blue wavelength, it was found to have a high correlation with the subject's cognitive skin tone, particularly in the continuous wavelength region of 400 to 490 nm.

<Reference Example 4> Correlation analysis between cognitive skin tone and skin reflection spectrum 2

From the analysis results of Reference Example 3, in order to compare the correlation between the skin tone index (T) which is an index according to the present invention and cognitive skin tone in more detail, the following experiment was performed.

1. Cognitive skin tone evaluation

Eight experts evaluated the brightness of the images obtained by photographing the faces of all subjects, and set the grade using a 9-point scale from 1 of very dark to 9 of very bright.

2. Measurement of actual skin tone using a spectrometer

Before measurement, the faces of all subjects were washed with cleansing foam (Foam) and then waited for 15 minutes in constant temperature and humidity conditions (22 ± 2 ° C, 45 ± 5% RH). The skin reflection spectrum was measured using a spectrometer (CM-2600d, Konica Minolta), the optical resolution of the used spectrometer is 0.01%, and the measurable wavelength range is 360-740 nm. The spectrum of the reflected light was obtained by measuring the front cheek area using a spectrometer. Significant correlation was analyzed using ANOVA (SPSS One-way) after skin tone measurement. The results of correlation analysis between cognitive skin tone and actual skin tone are shown in FIG. 5 below (p = 0.33).

3. Correlation analysis result between cognitive skin tone and skin reflection spectrum

As shown in FIG. 5, in response to the increase in the cognitive grade from 3 to 7, the cognitive skin tone was also found to increase from 18.81 to 20.38, which is an index according to the present invention. Through this, it can be confirmed that it has a significant correlation between the skin tone index (T), which is an index according to the present invention, and the perceived skin tone.

<Test Example 1> Skin tone improvement efficacy evaluation test of skin tone improvement products

The following experiments were performed to evaluate the skin tone improvement efficacy of the skin tone improvement products using the skin tone index (T), which was found to have a significant correlation with the cognitive skin tone in Reference Examples 1 to 4.

As an experimental method, the face of a healthy Korean woman was washed with cleansing foam (Foam) and then waited for 15 minutes in constant temperature and humidity conditions (22 ± 2 ° C, 45 ± 5% RH). The skin tone and skin reflection spectrum of the front cheek area of the subject's face were measured in the same manner as in Reference Examples 2 to 4 to calculate the skin tone index (T).

The product (Product 1, Product 2 and Product 3) to evaluate the effect of improving skin tone on the front cheek area of the subject was used twice a day for 28 days. After 28 days, the skin color and the skin reflection spectrum were measured again in the same manner as above for the same area on the front face of the subject's face. The skin tone and skin reflection spectrum of the front cheek area of the subject's face were measured in the same manner as in Reference Examples 2 to 4 to calculate the skin tone index (T).

Table 2 shows the results of statistical analysis (SPSS 20.0) by paired T-test for the skin tone index increase rate (T _a -T _b ) * 100 / T _b before and after application of the test substance.

division Test personnel (T _a -T _b ) * 100 / T _b p-value Product 1 16 people 1.100 0.028 Product 2 23 people 1.787 0.007 Product 3 23 people 1.812 0.004

As shown in Table 3, as a result of the experiment using the skin tone index (T), which is an index according to the present invention, it was confirmed that the p-value was less than 0.05, showing a statistically significant difference. In addition, in light of the (T _a -T _b ) * 100 / T _b values of 1.100, 1.787, and 1.812, respectively, for Product 1, Product 2, and Product 3, objectively precisely improve the skin tone improvement efficacy of the product under test It was found that it was confirmed.

Although the invention has been described in connection with the preferred embodiments mentioned above, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the appended claims will include such modifications or variations as long as they belong to the subject matter of the present invention.

Claims (8)

(a) before and after applying the test substance to a predetermined area of the subject's skin, measuring reflectance in the visible light wavelength range and storing the measured value;
(b) calculating the skin tone index (T _b ) before application of the test substance and the skin tone index (T _a ) after application by processing the measured values stored in the step (a) in an operation unit in which Equation 1 below is set; And
(c) _a method for evaluating the efficacy of improving the skin tone of the test substance, comprising the step of outputting a skin tone index increase rate (T _a -T _b ) * 100 / T _b before and after application of the test substance:
[Equation 1]

(T: skin tone index,
S: reflectance measured in the violet, blue, or violet to blue wavelength range,
Rt: reflectance measured over the entire visible wavelength range). According to claim 1,
In the step (a), the visible light wavelength range is characterized in that the wavelength range of 400 to 700 nm, skin tone improvement efficacy evaluation method of the test substance. According to claim 1,
In the step (c), the skin tone index increase rate (T _a -T _b ) * 100 / T _b before and after application of the test substance is determined to be effective in improving skin tone, and the determination result is determined. Characterized in that the step of output, a method for evaluating the efficacy of the test substance to improve skin tone. According to claim 1,
The purple region is 400 to 455 nm, the blue region is 455 to 490 nm, and the purple to blue wavelength region is characterized in that the wavelength region of 400 to 490 nm, skin tone improvement efficacy evaluation method of the test substance . (a) before and after applying the test substance to a predetermined area of the subject's skin, measuring reflectance in the visible light wavelength range and storing the measured value;
(b) calculating the skin tone index (T _b ) before application of the test substance and the skin tone index (T _a ) after application by processing the measured values stored in the step (a) in an operation unit in which Equation 1 below is set; And
(c) _a method for screening a substance having a skin tone improving activity, comprising outputting a skin tone index increase rate (T _a -T _b ) * 100 / T _b before and after the application of the test substance:
[Equation 1]

(T: skin tone index,
S: reflectance measured in the violet, blue, or violet to blue wavelength range,
Rt: reflectance measured over the entire visible wavelength range). The method of claim 5,
In the step (a), the visible light wavelength range is characterized in that the wavelength range of 400 to 700 nm, screening method of a material having a skin tone improving activity. The method of claim 5,
In the step (c), the skin tone index increase rate (T _a -T _b ) * 100 / T _b before and after application of the test substance is determined to be effective in improving skin tone, and the determination result is determined. Characterized in that the step of outputting, a screening method for a material having a skin tone improving activity. The method of claim 5,
The purple region is 400 to 455 nm, the blue region is 455 to 490 nm, and the purple to blue wavelength region is a wavelength region of 400 to 490 nm, characterized in that the skin tone improving activity screening method .

Images