JPS61181436A - Method and apparatus for measuring viscoelasticity of skin - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and a device for measuring the mechanical properties of the skin, in particular the viscoelasticity of the skin.

[Conventional technology]

Measuring the mechanical properties of the skin was performed primarily by dermatological clinicians using excised skin, targeting abnormal winds. These types of skin have obvious differences in morphology when viewed with the naked eye, and are relatively easy to measure as they have large differences as measurement targets.

On the other hand, the skin that cosmetics technicians deal with is normal skin with small differences in morphology, and it is impossible to remove the skin for measurement.

Cosmetics and the physiological properties of the skin are closely related, and the skin has long been a subject of study for cosmetic engineers.

We aim to improve the accuracy of the physiological effects of cosmetics on the skin, which have been understood intuitively, such as smoothing the skin, making the skin supple, or firming the skin. In order to quantify it and demonstrate its effectiveness, it is desirable to measure the mechanical properties of the skin in living organisms.

Conventionally, the mechanical properties of the skin, especially the viscoelasticity of the skin, have been measured without removing the skin (several methods are known in living organisms, but the equipment is large, the burden on the person being measured, the reproducibility, the measurement It wasn't accurate enough.

One of the relatively advanced methods is the so-called 2.■ cylinder method. The double cylinder method uses the outer cylinder to hold the skin surface while rotating the inner cylinder in a certain direction with a constant torque, and calculates the viscoelasticity of the skin from the rotation angle when the stress and torque combine and the rotation stops. It is something. Another method is the suction cup method, in which a cup with a circular cross section is placed on the measurement area, and the viscoelasticity is measured from the height of the lifted skin by vacuuming the inside of the pump at a constant speed. This is the way to do it.

[Problem that the invention seeks to solve]

The conventional double cylinder method or suction cup method is an extremely advanced method in terms of measuring the mechanical properties of skin in a living body compared to measurements using cut skin in terms of understanding the actual properties of the skin. However, both methods are static measurements in which the skin is displaced in only a certain direction.

Such static measurements provide less information than dynamic measurements that apply periodic displacement to the skin, and have not yet been able to provide satisfactory measurement results.

This invention solves the problems seen in the double cylinder method and the suction cup method, and makes it possible to perform dynamic skin measurements in living organisms using an extremely simple method.

[Means for solving problems]

In order to solve the above problems, the measurement method of the specified invention takes measures such as fixing the periphery of the measurement site, applying periodic force to the measurement site, and responding to the applied periodic force. The method is characterized in that the stress from the skin is measured, and the mechanical properties of the skin are measured based on the waveform of the applied force and the waveform of the stress from the skin.

Further, the measuring device of the second invention includes: a cylindrical attachment that contacts the periphery of the measurement site and fixes the skin; a means for applying a periodic force to the skin within a range defined by the attachment; and means for detecting stress from the skin corresponding to the periodic force applied.

[Effect]

While fixing the area around the measurement site and defining the measurement area, periodic force is applied to the measurement site to perform dynamic measurements of the skin, and the mechanical properties of the skin are measured.

〔Example〕

Preferred embodiments of the invention will be described below with reference to the drawings.

The measurement method of the present invention applies periodic force to the skin measurement site while holding the area around the measurement site so as not to be displaced by the periodic force applied to the measurement site. and measure the cyclic stress from the skin.

Regarding the obtained measurement data, viscosity, elasticity, phase difference (t
anδ), maximum stress/amplitude (D, S, R,), area of lisanoyu, and their respective fractions and standard deviations are calculated to know the mechanical properties of the skin. Note that the measurement data contains unnecessary signals caused by the subject's body movements, blood flow, breathing, heartbeat, etc., which degrades measurement accuracy and reproducibility, so it is necessary to remove unnecessary signals. preferable. The unnecessary signal contains many high frequency components compared to the original response, so for example, 100Hz.
is removed using a low-pass filter with a cutoff of For the remaining unnecessary signals, a determination function for determining the waveform is set, and based on these values, the quality of the data is determined, and defective data is rejected. Figure 1 schematically shows the measurement method and apparatus, in which the periphery of the measurement site is held down with a cylindrical attachment (1), and the disc (2) inside the attachment (1) is held down.
) is pressed against the skin surface and rotated and vibrated periodically using an electromagnetic vibrator (3). The stress from the skin caused by this rotation is measured with a torque meter (4) installed coaxially with the rotation axis of the disk (2). The electromagnetic exciter (3) is an amplifier (5)
This oscillator (6) is driven by an oscillator (6) amplified by
) and the torque signal measured by the torque meter (4) are input to the A/D humbator (7), converted, and input to the computer (8).The computer (8) converts the given waveform and From the stress waveform, the viscoelasticity of the skin is analyzed using, for example, the Malfwitz analysis method.

The cylindrical 7-tantiment (1) presses the periphery of the measurement site to define the measurement range. The attachment (1) has a diameter that defines the periphery of the measurement site, and the attachment (1)
The distal end surface of is formed into a contact surface (9) with a high coefficient of friction in order to fix the skin. The contact surface (9) is, for example, the seventh
．． As shown in Figure 8, file-like uneven parts (10) and (11) are formed using the 7-oto etching method, and by pressing the attachment (1) with a light force, the periphery of the measurement site is It is best to securely fix it. Do not fix the attachment (1) to the skin with too much force (
When pressed, the skin deforms due to this stress, which affects the measured value and also increases the burden on the person being measured, so it is extremely effective to use a contact surface (9) with a high coefficient of friction.

The attachment (1) is fixed to the skin by using instant adhesive or other adhesive on the contact surface (9) instead of the contact surface (9) with a high coefficient of friction formed with the aforementioned file-like uneven portions (10) and (11). Although it may be possible to use double-sided tape to secure the device to the skin, this poses an inconvenience in that it places a burden on the person being measured and complicates the measurement procedure. Alternatively, a method of fixing the measurement site using reduced pressure by a vacuum may be considered, but this method increases the size of the device and has problems such as difficulty in adjusting the pressure.

A contact surface with a high coefficient of friction similar to that of the attachment (1) is also formed on the skin contact surface (12) of the disc (2) that applies rotational vibration to the skin.

The contact surface on which the above-mentioned file-like unevenness (to) Bt) is formed is formed by forming four parts (10) which are photo-etched irregularly or regularly using a sensitive resin on the surface of the metal plate. A large number of edge lines (10) are produced by filing. The recess (10) is 100-300
It has a diameter of microns and a depth of 10 to 80 microns, and the spacing between adjacent edge lines is 10 to 100 microns.

Figure 4 shows one modification, in which a triple cylinder is inserted, the skin is fixed with the outer cylinder (13), and the inner fi (1
4) is rotated and vibrated to give distortion to the skin, and the middle fi21 (
15), the displacement of the skin is detected and the efficacy is measured using a torque meter installed on the same axis.

Figure PA5.6 shows yet another embodiment, in which instead of the rotational vibrations rising on the disk (2), the arm (16
) is caused to vibrate sinusoidally in a linear direction to apply a sinusoidal mechanical strain to the skin. Then, stress from the skin is measured by stress detection means (17) such as a strain meter or a pressure-sensitive sensor provided on the arm (1B). The vibration of the arm (16) is generated by a sine wave oscillator (18) to generate a sine wave for driving, and an amplifier (
19) to amplify the voltage sufficient for driving and drive coil (
20). The arm (16) is linearly and sinusoidally vibrated by driving the fill (20). In addition, the arm (16
) is of course not limited to the method using such a sine wave oscillator, but there is also a method of mechanically generating vibration using a cam, a method of driving by a logic circuit using a stepping motor, a computer, etc. etc. are possible.

The stress received by the arm (16) is measured by stress detector 8. (1)
), amplified by an amplifier (21), and input to a computer (22). The computer (22) analyzes the viscoelasticity of the skin from the applied waveform and stress waveform in the same manner as described above.

Fixing the periphery of the measurement site with the attachment (1) is the same as in Figures 1 to 4 above, and the attachment (
Similarly, the contact surfaces of 1) and 7-m (16) with the skin are formed to have a high coefficient of friction.

〔Effect of the invention〕

According to this invention, since it is possible to dynamically measure a certain area of skin using a ring-shaped presser foot, it is possible to improve the reproducibility of measurement, and also to improve static measurement. Compared to lIl! Since a much larger amount of information can be obtained and there is less influence on the person being measured, it is advantageous to measure the viscoelasticity of the skin more accurately.

This makes it possible to more clearly separate and quantify the sensory properties of the subject, such as "swelling,""tightness," and "firmness." It also has the advantage of reducing the burden on the person being measured. Moreover, information in the depth direction can also be obtained by changing the measurement frequency.

[Brief explanation of drawings]

Fig. 1 is a block diagram schematically showing the present invention, Fig. 2 is a perspective view of the attachment, Fig. 3 is a bottom view thereof, Fig. 4 is a perspective view showing one modification, and Fig. 5 is a further modification. Fig. 6 is a block diagram schematically showing the deformation, Fig. 7 is an enlarged sectional view of the contact surface, and Fig. t148 is a plan view of the same. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (6)

[Claims] (1) While fixing the area around the measurement site, apply a periodic force to the measurement site, measure the stress from the skin corresponding to the applied periodic force, and compare the waveform of the applied force and the stress from the skin. A method for measuring skin viscoelasticity, comprising measuring the mechanical properties of the skin using a waveform. (2) The measuring method according to claim 1, wherein the periodic force applied is rotational vibration. (3) The measuring method according to claim 1, wherein the periodic force applied is a sinusoidal vibration in a linear direction. (4) A cylindrical attachment that comes into contact with the periphery of the measurement site and fixes the skin, a means for applying periodic force to the skin within the range defined by the attachment, and a skin corresponding to the applied periodic force. 1. A skin viscoelasticity measuring device comprising means for detecting stress from the skin. (5) Claim 4, characterized in that the means for applying periodic force to the skin comprises a disc member that rotates and vibrates.
Measuring device as described in section. (6) The measuring device according to claim 4, wherein the means for applying periodic force to the skin comprises a member that vibrates sinusoidally in a linear direction.