JP2001112742A - Method and apparatus for evaluating skin condition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow even an ordinary person to noninvasively and easily evaluate the condition of her skin, such as the degree of fatigue, etc. SOLUTION: Laser beams are made to simultaneously impinge on a plurality of measuring points on the skin, and the laser beams reflected from the skin are received and converted into blood flow signals. Signals corresponding to two or more specific frequency bandwidths are extracted from the blood flow signals, and the signal strengths which correspond to the different frequency bandwidths are compared with each other to evaluate the condition of the skin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating a skin condition which allows a laser beam to be incident on the skin and frequency-analyze the reflected light to easily examine the degree of skin fatigue and the like, and to be used therefor. To a device that

[0002]

2. Description of the Related Art Conventionally, in order to evaluate the degree of fatigue of the skin, a method of visual or palpation judgment by a professional judge or a method of measuring physical property values of a skin over many items has been performed.

[0003] In addition, the degree of skin fatigue is also evaluated using an excitatory state of the sympathetic nerve of the skin which affects the tone of the skin blood vessels and the secretory action of sweat glands as an index. In order to measure this index, skin sympathetic nerve activity and muscle sympathetic nerve activity are measured by the Microneurography method.

[0004]

The determination by visual inspection or palpation and the measurement of the physical properties of the skin over many items require experience and specialized knowledge, and cannot be easily performed by ordinary people.

In the measurement of sympathetic nervous activity, a needle electrode must be inserted from above the skin into nerves distributed on the skin and muscles, and this measuring method cannot be easily performed by ordinary people.

Accordingly, an object of the present invention is to make it possible for non-invasive and simple evaluation of the skin condition such as the degree of fatigue to be easily and non-invasively performed, and to display the evaluation result in a visually easy-to-understand manner.

[0007]

SUMMARY OF THE INVENTION We have developed a multi-channel laser tissue flowmeter.
A skin condition is obtained by obtaining a blood flow signal using a detection mechanism of a skin blood flow signal in a pler tissue blood flowmeter, extracting two or more specific frequency bands from the blood flow signal, and taking a ratio between them. The inventors have found that it is possible to easily evaluate the degree of skin fatigue and the like by using this index, and have completed the present invention.

That is, according to the present invention, laser light is simultaneously incident on a plurality of measurement points on the skin, the reflected light of the laser light from the skin is received and converted into a blood flow signal. This is a method of extracting a signal of the above frequency band and comparing the signal strength of each frequency band to evaluate a skin condition.

Further, the present invention provides (i) a laser light source, (ii)
An optical splitter that divides laser light emitted from a laser light source into a plurality of light beams, (iii) a light transmitting terminal and a light transmitting terminal that simultaneously emit light beams of a plurality of light beams to a plurality of measurement points on the skin (Iv) a photodetector that converts light received at the light-receiving terminal into a blood flow signal, and (v) blood. The skin condition evaluation device includes a band-pass filter that extracts signals of at least two frequency bands from a flow signal, and (vi) a signal analysis unit that outputs a ratio of signal strength of each extracted frequency band.

[0010]

FIG. 1 is a block diagram of one embodiment of the skin condition evaluation apparatus of the present invention.

In this apparatus, a laser light source 1, a light splitter 2 for dividing a laser beam emitted from the laser light source 1 into a plurality of light beams, and light beams of the plurality of light beams are simultaneously incident on a plurality of measurement points on the skin. A sensor unit 5 including a light transmitting terminal 3 and a plurality of light receiving terminals 4 for receiving reflected light of light incident on the skin from the light transmitting terminal 3; A signal detector, a band-pass filter 7 for extracting signals in at least two frequency bands from the blood flow signal, and a signal analyzer 8 for outputting a ratio of the signal intensities of the extracted frequency bands. A monitor 9 and a printer 10 are connected to 8.

In this apparatus, a laser light source 1, an optical splitter 2, a sensor unit 5, and a photodetector 6 are composed of a conventional multi-channel laser dosimeter.
ppler tissue blood flowmeter) (JP-A-8-1826)
No. 58, etc.) can be used. However, on the end face of the sensor unit 5 on the side of contact with the skin, laser light is simultaneously incident on a plurality of measurement points on the skin, and the reflected light can be detected simultaneously for each measurement point. As shown in the frame, a large number of sensor elements 5a each including one light transmitting terminal 3 and one light receiving terminal 4 are arranged.

More specifically, the light transmitting terminal 3 and the light receiving terminal 4 are composed of optical fibers connected to the optical splitter 2 and the photo detector 6, respectively. In FIG. 1, for simplicity of description, only the uppermost row of the sensor elements 5 a arranged in the sensor unit 5 is shown as being connected to the optical splitter 2 and the photodetector 6. , Actually all the sensor elements 5
a, the light transmitting terminal 3 and the light receiving terminal 4 are connected to the light splitter 2 and the light detector 6, respectively. Light is input. The number of the sensor elements 5a shown here is an example, and there is no particular limitation.

By providing a large number of sensor elements 5a in the sensor section 5 and simultaneously detecting blood flow signals at a large number of measurement points on the skin, the skin condition can be evaluated with a two-dimensional spread. Become.

The band-pass filter 7 extracts signals in at least two frequency bands from the blood flow signal in order to read out information such as the sway of the blood vessel, the heart rate, and the nerve tension on the blood flow signal. Yes, it has a characteristic configuration with respect to the original multi-channel laser tissue blood flow meter that analyzes the blood flow of the tissue.

In the band pass filter 7, for example, when reading out information on the excitation state of the skin sympathetic nerve and the degree of skin fatigue, when the sample rate of the blood flow signal is 1 to 10 Hz, 0.04 Hz or more and less than 0.15 Hz; More preferably, a low frequency range of 0.06-0.11 Hz and 0.15H
z or higher frequency range, more preferably 0.15 to 0.50
The high frequency range of Hz is extracted.

In the present embodiment, the signal analyzing means 8 is realized by a personal computer,
The ratio of the signals in at least two frequency bands extracted in step (1) is calculated, and the skin condition is analyzed.

For example, the signal intensity (L
F) and the ratio (LF / H) of the signal strength (HF) in the high frequency range.
F) is an index of the excitation state of the skin sympathetic nerve, and the larger the value, the higher the excitation of the skin sympathetic nerve.

(LF / HF) is an index of the degree of skin fatigue, and the larger the value, the higher the degree of skin fatigue.

The signal ratio obtained in this way is not affected by fluctuations in the respiration rate during natural respiration or movements of the chest and the like, and is a highly reliable index of the skin condition.

After extracting a signal of a specific frequency band from the blood flow signal, frequency analysis may be performed by a fast Fourier transform (FFT) or a maximum entropy method (MEM) to obtain a power spectrum or the like of the specific frequency band. .

The signal analyzing means 8 may store a signal in a specific frequency band extracted from the blood flow signal, if necessary, and perform an analysis using the stored signal.

The computer including the signal analyzing means 8 includes:
A display means such as a monitor 9 or a printer 10 is connected to display the evaluation result of the skin condition obtained by the signal analysis means 8. As the display mode, the evaluation results of many measurement points
It is preferable to arrange the evaluation values in a dimensional manner and visualize each evaluation numerical value by shading or the like, since it becomes extremely easy to grasp the skin condition. As a display mode, the evaluation result of the skin condition may be displayed in a moving image over a certain time interval, or the average value of the evaluation result of the skin condition in that time (for example, one minute) may be displayed in a still image. You may.

The method of evaluating the skin condition of the present invention is performed as follows using the above-described apparatus of the present invention.

First, as in the case of measuring blood flow with a conventional multi-channel laser tissue blood flow meter, the sensor unit 5 is used.
To the skin, and simultaneously irradiate the skin with laser light from the light transmitting terminals 3 of each of the large number of sensor elements 5a, and receive the reflected light at the light receiving terminals 4 of each of the sensor elements 5a. At step 6, it is converted into a blood flow signal. Thereby, a blood flow signal of the dermis up to about 2 mm from the surface can be obtained.

There is no particular limitation on the site of the skin to be measured, but it is preferable that the site where the sympathetic nerve of the cutaneous blood vessels predominantly acts, such as the forehead or the palm, is measured.

The measuring time depends on the sampling interval and the like, but is preferably about several minutes. This makes it possible to evaluate not the instantaneous state of the skin but a steady state.

After the blood flow signal is obtained by the photodetector 6, signals in two or more specific frequency bands are extracted by the band-pass filter 7, and the signal intensity of each frequency band is compared by the signal analyzing means 8. The result is displayed on a monitor or a display device such as a printer. Thus, the skin condition can be easily evaluated noninvasively.

[0029]

EXAMPLE 1 Twenty healthy women in their forties were divided into two groups, Group A and Group B,
Group A was subjected to a 20-minute massage of the whole body once a day, and Group B was a control group that did not perform the massage. Using the apparatus of FIG. 1 (light source: semiconductor laser, wavelength: 830 nm), the blood flow signal of the skin at the corner of the mouth was measured before and 4 weeks after the treatment, and 0.06 to 0.1 extracted from the blood flow signal
The signal strength (LF) in the low frequency range of 1 Hz is 0.15 to
The signal strength (HF) in the high frequency range of 0.50 Hz was measured. As an index of the degree of skin fatigue at the measurement site, LF / HF,
The beam index, moisture index, dullness index and wrinkle index were determined.

Here, the beam index is defined as 1 from the state where there is no beam to the state where each subject is palpated by five professional judges.
Judgment values in the case of judging in 10 steps were obtained, and the average value was used as a beam index.

The moisturizing index is a judgment value obtained when five expert judges determine each subject by a palpation by classifying the subject from unmoistened state to moistened state in 1 to 10 steps, and average the average value. The index was used.

[0032] The dullness index is defined as a score from 1 to 5 when a professional expert visually judges each subject from dullness to dullness.
Judgment values obtained when the judgment was made in 10 steps were obtained, and the average value was used as the dullness index.

The wrinkle index is a wrinkle index obtained by visually judging each subject from a wrinkled state to a wrinkle-free state in 1 to 10 steps, and the average value thereof is obtained. The index was used.

The results are shown in FIGS. FIG. 4-
FIG. 7 shows the effect of improving the skin condition by massage for each of the judgment items, but it can be seen from FIGS. 2 and 3 that LF / HF decreases after massage. Therefore, it can be seen that LF / HF is an index of the degree of skin fatigue.

Example 2 Twenty healthy women in their twenties were divided into two groups, Group A and Group B.
From 6:00 am to the end of the measurement on the next day, the acclimation was performed in a temperature and humidity environment of 25 ° C. and 50%. Group A was allowed to sleep overnight, and Group B was allowed to sleep for 8 hours from 10 pm to 6 am the next day, and was used as a control group. The skin on the cheek was used as a measurement site, and LF / HF, beam index, and dullness index were used as indices of the degree of skin fatigue at the measurement site in the same manner as in Example 1 at 8:00 am on the first day and morning on the second day. I asked at 8 o'clock.

The results are shown in FIGS. FIG.
0 and FIG. 11 show the fatigue of the skin due to staying up all night for each of the judgment items. However, FIGS. 8 and 9 show that LF / HF increases after all night. Therefore, it can be seen that LF / HF is an index of the degree of skin fatigue.

[0037]

According to the method for evaluating the skin condition of the present invention, or by using the evaluation device of the present invention, the skin condition such as the degree of fatigue can be easily and non-invasively evaluated by ordinary people, Further, it is possible to display the evaluation result visually in an easily understandable manner. Therefore, the present invention is useful for evaluation of products that improve skin fatigue such as care agents, proposal of concepts, and the like.

[Brief description of the drawings]

FIG. 1 is a block diagram of the device of the present invention.

FIG. 2 is a two-dimensional display of LF / HF of skin before the start of treatment.

FIG. 3 is a two-dimensional display of LF / HF of the skin four weeks after the start of the treatment.

FIG. 4 is a graph showing skin swelling indices before and 4 weeks after the start of treatment.

FIG. 5 is a diagram showing the skin moisture index before and 4 weeks after the start of treatment.

FIG. 6 is a graph showing the dullness index of the skin before and 4 weeks after the start of the treatment.

FIG. 7 is a diagram showing wrinkle indexes of skin before and 4 weeks after the start of treatment.

FIG. 8 is a two-dimensional display of LF / HF of the skin on the first day.

FIG. 9 is a two-dimensional display of LF / HF of the skin on the second day.

FIG. 10 is a diagram showing the skin index on the first day and the second day.

FIG. 11 is a diagram showing the dullness index of the skin on the first day and the second day.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser light source 2 Optical splitter 3 Light transmission terminal 4 Light reception terminal 5 Sensor part 5a Sensor element 6 Photodetector 7 Bandpass filter 8 Signal analysis means

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Yukihiro Yada 2-1-3 Bunka, Sumida-ku, Tokyo F-term in Kao Corporation Research Laboratories (reference) 4C038 VA04 VB22 VC01 VC02

Claims (4)

[Claims] 1. A laser beam is incident on a plurality of measurement points on the skin at the same time, a reflected light of the laser beam from the skin is received and converted into a blood flow signal, and two or more specific frequency bands are converted from the blood flow signal. A method of extracting skin signals and comparing the signal strength of each frequency band to evaluate the skin condition. 2. The method according to claim 1, wherein the signal strength ratio is displayed two-dimensionally.
The evaluation method of the described skin condition. 3. A laser light source, (ii) an optical splitter for dividing a laser beam emitted from the laser light source into a plurality of light beams, and (iii) a plurality of skin light beams simultaneously measured by the plurality of light beams. A sensor unit comprising a light transmitting terminal to be incident on a point and a plurality of light receiving terminals for receiving reflected light of light incident on the skin from the light transmitting terminal, and (iv) light received by the light receiving terminal. (V) a band-pass filter for extracting signals of at least two frequency bands from the blood flow signal, and (vi) a signal analyzing means for outputting a ratio of the extracted signal intensities of the respective frequency bands. , A skin condition evaluation device. 4. The evaluation of skin condition according to claim 3, wherein the light source, the optical splitter, the sensor unit and the photodetector comprise a light source, an optical splitter, a sensor unit and a photodetector of a multichannel laser tissue blood flow meter. apparatus.