JP2013138720A - Measuring apparatus and measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quantify a fluorescent material only existing on epidermis and dermis.SOLUTION: A measuring apparatus includes: an irradiation part 100 for irradiating a living body with excitation light guided from an excitation light source; a fluorescent spectrum measuring part 102 for measuring a fluorescent spectrum related to fluorescence generated by the irradiation of the excitation light; and an angle change mechanism for changing an irradiation angle of the excitation light to the living body.

Description

  The present invention relates to a measuring apparatus and a measuring method using fluorescence characteristics obtained using excitation light.

  Conventionally, anti-glycation (anti-aging) cosmetics have been commercialized for the purpose of reducing AGEs (Advanced Glycation End products) accumulated in the skin. These AGEs are final products formed by a non-enzymatic sugar addition reaction (Maillard reaction) between proteins and carbohydrates or lipids, exhibiting a yellowish brown color, and some of them are fluorescent substances. In addition, AGEs have a property of forming a crosslink by binding to a nearby structural protein. In particular, the cross-linking of AGEs with collagen constituting the dermis lowers the elasticity of the skin, which is a problem as a cause of wrinkles and dullness.

  In addition to AGEs, there are substances that exhibit fluorescence other than AGEs, for example, fluorescent substances such as hydroxyproline, riboflavin, nicotinamide adenine dinucleotide (NADH), protoporphyrin, tyrosine, tryptophan, and elastin. Evaluation of these substances is useful from the viewpoint of obtaining information for obtaining a guideline that influences beauty and health, and for the purpose of grasping an inhibiting factor other than AGEs.

  In this regard, as a technique applicable to measuring AGEs and other fluorescent substances in the skin, for example, there is a technique disclosed in Patent Document 1 below.

  Further, regarding AGEs and other fluorescent substances present in the skin, there are different types depending on a specific depth region in the skin, and the existing amounts are also different.

  For example, AGEs in the epidermis region (surface to depth of about 0.2 mm) or in the dermis region (depth of about 0.2 to 2.2 mm) reduce skin elasticity and cause wrinkles and dullness. Therefore, it is a bad factor from a cosmetic point of view. A commercially available cream or the like for eliminating this cause of badness works to reduce AGEs in the epidermis and dermis.

  Furthermore, AGEs are also present in the blood vessel region (depth of about 2.2 mm or less). In the case of diabetes, AGEs increase with an increase in blood glucose, and therefore, early detection or progress of diabetes can be grasped by monitoring AGEs. In addition, as means for reducing AGEs in blood, there are antidiabetic drugs and functional foods, which directly control the amount of AGEs in blood.

  Thus, it is extremely useful to grasp the amount of AGEs in a specific depth region (skin region, dermis region, blood vessel region) in the skin.

JP 2004-290234 A (released on October 21, 2004)

  However, the technique disclosed in Patent Document 1 is insufficient in terms of quantifying fluorescent substances present only in the epidermis and dermis for various AGEs.

  This is because Patent Document 1 does not describe at all that the types and amounts of AGEs differ depending on the skin depth. That is, Patent Document 1 does not disclose a problem that it is necessary to quantify fluorescent substances existing only in the dermis and epidermis for various types of AGEs.

  In view of the above-described conventional problems, the present invention can provide a measuring apparatus and a measuring method capable of quantifying a fluorescent substance existing only in the epidermis and dermis with a simple configuration.

  In order to solve the above problems, the measuring apparatus of the present invention irradiates a living body with excitation light guided from an excitation light source, and fluorescence spectrum measurement that measures a fluorescence spectrum related to fluorescence generated by the irradiation of the excitation light. And an angle changing mechanism for changing the irradiation angle of the excitation light to the living body.

  When the irradiation angle of the excitation light with respect to the living body (the angle formed by the normal direction of the surface irradiated with the excitation light in the living body and the irradiation direction of the excitation light) is small, the excitation light is not so strong when traveling in the living body. Does not decay. That is, the excitation light is irradiated to both the fluorescent substance (referred to as fluorescent substance A) present in the epidermis and dermis region and the fluorescent substance (referred to as fluorescent substance B) present in the blood vessel region. Thereby, in the fluorescence spectrum measured by the fluorescence spectrum measuring unit, the peak of the fluorescent substance A is hidden behind the peak of the fluorescent substance B, and the peak of the fluorescent substance A may not be recognized.

  However, since the present invention includes the angle changing mechanism, the irradiation angle of the excitation light with respect to the living body can be changed. Thereby, the irradiation angle of the excitation light with respect to the living body can be increased. When the irradiation angle is increased in this way, the propagation distance of the excitation light traveling in the living body becomes larger than when the irradiation angle is small.

  That is, when the irradiation angle is increased, the intensity of the excitation light applied to the fluorescent material A becomes larger than the intensity of the excitation light applied to the fluorescent material B than when the irradiation angle is small. Thereby, in the fluorescence spectrum measured by the fluorescence spectrum measuring unit, the peak value corresponding to the fluorescent substance A appears more clearly than the peak value corresponding to the fluorescent substance B. Recognized reliably

  As described above, according to the present invention, the fluorescent substance existing only in the epidermis and the dermis can be quantified with a simple configuration in which an angle changing mechanism is provided.

  Furthermore, the measurement apparatus of the present invention is the measurement apparatus having the above-described configuration, wherein the fluorescence spectrum measurement unit calculates the fluorescence spectrum for each of a plurality of irradiation angles set by changing the irradiation angle by the angle changing mechanism. In addition to measuring, the fluorescence spectrum that maximizes the peak intensity at a specific wavelength among the plurality of measured fluorescence spectra is obtained as the peak intensity generation fluorescence spectrum, and the irradiation angle at which the peak intensity generation fluorescence spectrum is obtained is determined as the peak intensity. It is preferable to determine the generated irradiation angle.

  According to the above configuration, the fluorescence spectrum measurement unit obtains a fluorescence spectrum having the maximum peak intensity at a specific wavelength among the measured plurality of fluorescence spectra as a peak intensity generation fluorescence spectrum.

  Thus, for example, if the wavelength at which the fluorescence peak corresponding to the fluorescent substance A appears is a specific wavelength, the fluorescence corresponding to the fluorescent substance A present in the dermis and epidermis among the fluorescence spectra measured for each of the plurality of irradiation angles. The fluorescence spectrum having the maximum intensity is obtained as the peak intensity generation fluorescence spectrum.

  If the peak intensity generation irradiation angle is obtained as the irradiation angle at which the peak intensity generation fluorescence spectrum is obtained, it is only necessary to set the excitation light irradiation angle to the peak intensity generation irradiation angle when measuring the fluorescence spectrum thereafter. A fluorescence spectrum with the maximum fluorescence peak corresponding to the fluorescent substance A can be easily obtained. Thereby, the quantification of the fluorescent substance A existing only in the epidermis and dermis can be performed with high reproducibility.

  The peak intensity generation fluorescence spectrum is a fluorescence spectrum in which the peak intensity at a specific wavelength is maximized. Therefore, even if there is a fluorescent substance that exhibits a fluorescent peak at a wavelength other than the specific wavelength, the presence of the fluorescent substance that exhibits a fluorescent peak at the specific wavelength can be clearly grasped by measuring the peak intensity generation spectrum. In this regard, according to the above-described configuration, the measurement relating to the fluorescent substance existing only in the epidermis and the dermis can be selectively performed without being influenced by other fluorescent substances.

  Furthermore, the measuring apparatus of the present invention is the measuring apparatus having the above-described configuration, wherein the irradiation angle is defined as an angle formed by a normal direction of a surface of the living body irradiated with the excitation light and an irradiation direction of the excitation light. In this case, the intensity of the specific wavelength relating to the peak intensity generation fluorescence spectrum does not occur when the irradiation angle is small, but corresponds to the peak value of the fluorescence intensity generated when the irradiation angle is large. preferable.

  According to the above configuration, the fluorescence spectrum measurement unit does not occur when the irradiation angle is small, and the fluorescence intensity peak value generated when the irradiation angle is large is the maximum among the plurality of measured fluorescence spectra. The spectrum is determined as the peak intensity generation fluorescence spectrum.

  This makes it possible to accurately grasp the presence of the fluorescent substance present in the dermis and epidermis.

  Furthermore, the measurement apparatus of the present invention is the measurement apparatus having the above-described configuration, in which the fluorescence spectrum measurement unit obtains a fluorescence spectrum of fluorescence generated when the living body is irradiated with the excitation light at a first irradiation angle. Measuring as a fluorescence spectrum, measuring a fluorescence spectrum of fluorescence generated when the living body is irradiated with the excitation light at a second irradiation angle that is different from the first irradiation angle, It is preferable to perform a relative comparison between the first fluorescence spectrum and the second fluorescence spectrum.

  According to the above configuration, the first fluorescence spectrum measured when the excitation light is irradiated at the first irradiation angle and the second fluorescence spectrum measured when the excitation light is irradiated at the second irradiation angle. And you can get Thereby, the peak value of the first fluorescence spectrum measured at the first irradiation angle and the peak value of the second fluorescence spectrum measured at the second irradiation angle can be relatively compared.

  Then, using the peak value of the fluorescence spectrum corresponding to the known fluorescent substance and the magnitude relationship between the first irradiation angle and the second irradiation angle as a clue, the existence area of the unknown fluorescent substance relative to the existing area of the known fluorescent substance is determined. The relative depth can be determined.

  For example, it is assumed that the first fluorescence spectrum shows a peak value A1 corresponding to a known fluorescent substance and a peak value B1 corresponding to an unknown fluorescent substance. Similarly, it is assumed that the second fluorescence spectrum shows a peak value A2 corresponding to a known fluorescent substance and a peak value B2 corresponding to an unknown fluorescent substance. Further, when the peak value A1 and the peak value A2 are normalized so as to have the same magnitude, the peak value B2 is larger than the peak value B1, and the second irradiation angle is larger than the first irradiation angle. Assume that there is.

  In this case, it can be determined that many unknown fluorescent substances are present in a shallower area than the known fluorescent substance, for example, in the epidermis or dermis area.

  As described above, according to the above configuration, it is possible to grasp the depth at which the fluorescent substance existing in the living body exists from the measured first fluorescence spectrum and second spectrum.

  Furthermore, the measurement apparatus of the present invention is the measurement apparatus having the above-described configuration, wherein the fluorescence spectrum measurement unit has a wavelength at which the fluorescence intensity in the first fluorescence spectrum has a peak value, and the fluorescence intensity in the second fluorescence spectrum has a peak value. In the case where the same wavelength region exists in the same wavelength region, it is preferable to obtain a differential fluorescence spectrum obtained by subtracting the first fluorescence spectrum and the second fluorescence spectrum.

  According to the above configuration, a differential fluorescence spectrum obtained by subtracting the first fluorescence spectrum and the second fluorescence spectrum is obtained. Thereby, it is possible to obtain a fluorescence spectrum of a fluorescent substance existing at a specific depth in a living body and having a reduced influence of the fluorescent substance existing in another region as a difference spectrum.

  For example, similarly to the above-mentioned assumption, it is assumed that the first fluorescence spectrum shows a peak value A1 corresponding to a known fluorescent substance and a peak value B1 corresponding to an unknown fluorescent substance. Similarly, it is assumed that the second fluorescence spectrum shows a peak value A2 corresponding to a known fluorescent substance and a peak value B2 corresponding to an unknown fluorescent substance. Further, when the peak value A1 and the peak value A2 are standardized to have the same magnitude, the peak value B2 is larger than the peak value B1, and the second irradiation angle is larger than the first irradiation angle. Assume that

  In this case, it can be seen that many unknown fluorescent substances exist in a shallower region than the known fluorescent substances. That is, if the known fluorescent substance is a fluorescent substance present in the blood vessel region, it can be determined that many unknown fluorescent substances are present in the epidermis or dermis region. Then, the difference between the first fluorescence spectrum and the second fluorescence spectrum is obtained to obtain a differential fluorescence spectrum, thereby reducing the influence of unknown fluorescent substances existing in the epidermis and dermis area, and corresponding to known fluorescent substances existing in the blood vessel area. A fluorescence spectrum can be obtained.

  Furthermore, the measurement apparatus of the present invention preferably includes a light source that emits excitation light having a plurality of different wavelengths as the excitation light source in the measurement apparatus having the above configuration.

  According to the above configuration, it is possible to select a plurality of optimum wavelengths for exciting each of the various fluorescent substances existing in the living body, and to emit excitation light of the selected plurality of wavelengths from the light source. Thereby, it is possible to obtain a fluorescence spectrum in which the peak value corresponding to each fluorescent substance clearly appears, and to measure the fluorescent substance in the living body more accurately.

  Further, in the measurement apparatus of the present invention, when the plurality of wavelengths of the excitation light emitted by the excitation light source are the first wavelength and the second wavelength in the measurement apparatus having the above configuration, the fluorescence spectrum measurement unit includes the The first correlation which is a correlation between the irradiation angle of the excitation light related to the first wavelength and the intensity of the fluorescence generated by the irradiation of the excitation light, the irradiation angle of the excitation light related to the second wavelength, and the excitation light It is preferable to make a relative comparison with the second correlation which is a correlation with the intensity of the fluorescence generated by the irradiation.

  According to the above configuration, it is possible to more accurately determine the relative depth between different fluorescent substances present in the living body.

  Further, in the measuring apparatus of the present invention, it is preferable that the excitation light has a wavelength range suitable for measuring AGEs (Advanced Glycation End products).

  According to the said structure, the latter stage saccharification reaction product as a fluorescent substance can be quantified more correctly.

  Furthermore, the measuring apparatus of the present invention preferably includes a collimating lens in the optical path from the excitation light source to the living body in the measuring apparatus having the above configuration.

  According to the said structure, the excitation light irradiated to a biological body turns into a substantially parallel light by a collimating lens. Thereby, the irradiation angle with respect to the living body of the light traveling in the center of the optical axis in the excitation light and the irradiation angle of the light traveling in a portion other than the center of the optical axis in the excitation light are substantially equal.

  That is, since it is possible to irradiate the living body with the excitation light at a uniform irradiation angle, the fluorescence spectrum can be measured stably and can be measured with high accuracy.

  Further, in order to solve the above-described problem, the measurement method of the present invention is configured to irradiate a living body with excitation light guided from an excitation light source, and to change the irradiation angle of the excitation light with respect to the living body. For each of the irradiation angles, a fluorescence spectrum measuring step of measuring a fluorescence spectrum related to fluorescence generated by the irradiation of the excitation light is included.

  According to the measuring method including the above steps, the same effect as that of the measuring apparatus of the present invention can be obtained.

  According to the present invention, fluorescent substances existing only in the epidermis and dermis can be quantified.

FIG. 1 is a conceptual diagram for explaining a skin condition measuring apparatus according to an embodiment of the present invention. FIG. 2 is an optical simulation result showing the ratio of the excitation light intensity just below the skin surface and the excitation light intensity in the deepest dermis layer in relation to the value of the irradiation angle θ. FIG. 3 is a diagram showing the irradiation angle (θ1) of excitation light, the angle (θ2) in the light traveling direction in the skin, and the depth (t) from directly below the skin surface. FIG. 4A is a diagram showing a fluorescence spectrum measured when the excitation light irradiation angle θ is small, and FIG. 4B is a fluorescence spectrum measured when the excitation light irradiation angle θ is large. FIG. 4C is a diagram for explaining the definition of “peak intensity at a specific wavelength”. It is a figure which shows the state which sets the irradiation angle of excitation light to 80 degree | times, and irradiates skin with excitation light. FIG. 6A is a diagram showing a state in which excitation light is irradiated while diffusing to the skin surface, and FIG. 6B is a state in which excitation light is irradiated while converging on the skin surface. FIG. Fig.7 (a) is a schematic diagram which shows the whole apparatus structure of a skin condition measuring apparatus, FIG.7 (b) is sectional drawing in a surface parallel to the paper surface of a probe. FIG. 8A is a diagram showing a fluorescence spectrum obtained by setting the irradiation angle of the excitation light to an irradiation angle close to approximately 0 degrees, and FIG. 8B shows the irradiation angle as the first irradiation angle. It is a figure which shows the fluorescence spectrum obtained by setting to 2nd irradiation angle larger than this. FIG. 9 is a diagram showing a fluorescence spectrum measured by irradiating a test piece with excitation light having a wavelength of 365 nm (vertical irradiation) at an irradiation angle of approximately 0 degrees. FIG. 10 is a diagram illustrating a fluorescence spectrum measured by irradiating a test piece with excitation light having a wavelength of 290 nm (vertical irradiation) in a state where the irradiation angle is approximately 0 degrees. FIG. 11A shows a fluorescence spectrum obtained when the skin is irradiated with excitation light having a wavelength of 365 nm when the irradiation angle θ is large, and FIG. 11B shows a case where the irradiation angle θ is large. It is a figure which shows the fluorescence spectrum obtained when an excitation light with a wavelength of 290 nm is irradiated to skin. FIG. 12A is a diagram showing a fluorescence spectrum measured by irradiating the skin with excitation light having a wavelength of 365 nm. FIG. 12B is a diagram showing a fluorescence spectrum measured by irradiating the skin with excitation light having a wavelength of 290 nm. FIG. 12C is a graph showing how the peak intensity of the fluorescence spectrum shown in FIG. 12A changes when the irradiation angle is changed. FIG. 12D is a graph showing how the peak intensity of the fluorescence spectrum shown in FIG. 12B changes when the irradiation angle is changed. It is a figure which shows the definition of irradiation angle (theta) and depth T in skin. FIG. 14 is a graph showing the result of simulating the correlation between the peak intensity of the fluorescence spectrum and the irradiation angle. FIG. 15A is a diagram showing a measured fluorescence spectrum (first fluorescence spectrum) after setting the irradiation angle θ to be almost 0 degrees and a small value. FIG. 15B is a diagram showing a fluorescence spectrum (second fluorescence spectrum) measured after setting the irradiation angle θ not to 0 degrees but to a somewhat large value (about 60 degrees). It is a figure which shows the difference spectrum obtained by subtracting a fluorescence spectrum to FIG.11 (b) from the fluorescence spectrum shown to Fig.11 (a). FIG. 17 is a view for explaining a modification of the angle changing mechanism according to the measuring apparatus of the present invention. FIG. 18 is a view showing a modification according to the measuring apparatus of the present invention. FIG. 19A and FIG. 19B are diagrams showing a modification of the skin condition measuring apparatus of the present invention.

[1. Basic principle〕
FIG. 1 is a conceptual diagram for explaining a skin condition measuring apparatus (measuring apparatus) 100 according to an embodiment of the present invention. As shown in FIG. 1, the skin condition measuring apparatus 100 includes an irradiation unit 101 that irradiates a part of skin 103 with excitation light guided from an excitation light source, and a part of the skin that is irradiated with excitation light. And a fluorescence spectrum measuring unit 102 that measures a fluorescence spectrum related to the fluorescence generated by this.

  The fluorescence spectrum measuring unit 102 is configured by collecting optical devices such as a condensing lens, an optical fiber, and a spectroscope, but is schematically illustrated as one block in FIG. Further, the fluorescence spectrum measuring unit 102 has not only a function of measuring a fluorescence spectrum but also a function of performing various analyzes and operations on the measured fluorescence spectrum.

  Further, when the angle formed by the irradiation direction of the excitation light irradiated from the irradiation unit 101 and the normal direction of the surface irradiated with the excitation light in the skin 103 is an irradiation angle θ, the skin condition measuring apparatus 100 is zero. The skin 103 is irradiated with excitation light from the irradiation unit 101 at an irradiation angle θ set as a non-existing (greater than 0) value. The skin condition measuring apparatus 100 can measure the fluorescence spectrum related to the fluorescence generated by the irradiation of the excitation light as described above by the fluorescence spectrum measuring unit 102.

  The excitation light emitted from the irradiation unit 101 is used to excite the fluorescent substance in the skin 103. Further, the fluorescence spectrum measuring unit 102 is used for detecting fluorescence from the excited fluorescent substance. Substances that exhibit fluorescence in the skin include late-stage glycation end products (AGEs), hydroxyproline, riboflavin, nicotinamide adenine dinucleotide (NADH), protoporphyrin, tyrosine, tryptophan, and elastin. To do. And as a wavelength of the excitation light irradiated to skin, it is preferable to set it as 315-600 nm which is a wavelength range suitable for the measurement of the above-mentioned late saccharification reaction product, More preferably, if it shall be the range of 315-400 nm. Good.

  FIG. 2 is an optical simulation result showing the ratio of the excitation light intensity just below the skin surface and the excitation light intensity in the deepest dermis layer in relation to the value of the irradiation angle θ.

  More specifically, the vertical axis according to FIG. 2 represents the ratio of the excitation light intensity absorbed from directly under the skin surface to the deepest dermis layer and the excitation light intensity absorbed deeper than the deepest dermis layer. A relative value is shown with a value at 1 at an irradiation angle of 0 °. 2 represents the irradiation angle θ of the excitation light.

  As shown in FIG. 2, the numerical value on the vertical axis increases as the irradiation angle of the excitation light increases. This indicates that the excitation light intensity directly below the skin surface is relatively higher than that of the deepest dermis layer.

  In the optical simulation, the structure inside the skin surface was uniform, that is, the refractive index (real part) and the absorption coefficient were constant. Also, as shown in FIG. 3, the irradiation angle of the excitation light is θ1, the angle of the light traveling direction in the skin is θ2, the depth from just below the skin surface is t, the refractive index (real part) in the skin is n, The absorption coefficient is α, and the following equation is used as the excitation light intensity A.

  Using the above formula, the optical power absorbed from directly under the skin to the lowest layer of the dermis is

  Can be expressed as

  Also, the optical power absorbed deeper than the lowest layer of the dermis is

Can be expressed.
From these equations, the value on the vertical axis in FIG.

It calculated from the expression expressed as follows. The skin refractive index was 1.4, the absorption coefficient was 35 to 50 [cm ⁻¹ ], and the depth of the deepest dermis was 0.22 [cm].

  From FIG. 2, the relative value of the excitation light intensity from the skin surface to the deepest dermis layer with respect to the excitation light intensity below the deepest dermis layer when the θ is, for example, 60 degrees is 6 to 20 compared with the case of 0 degree. It has doubled. That is, when the excitation light is incident at an angle of θ1 = 60 degrees compared to the case where the excitation light is incident perpendicular to the skin surface (when θ = 0 degrees), the region from the skin surface to the deepest dermis layer is relatively 6 to 20 times stronger. Thereby, by using the skin condition measuring apparatus 100, information from the skin surface to a predetermined depth can be obtained.

  FIG. 4A and FIG. 4B are schematic conceptual diagrams of fluorescence spectra obtained using the skin condition measuring apparatus 100. In particular, FIG. 4A shows a fluorescence spectrum measured by the fluorescence spectrum measuring unit 102 when the irradiation angle θ of the excitation light is small (when θ is close to 0 degree), and two fluorescence peaks ( The first peak and the second peak) are measured. On the other hand, FIG. 4B shows a fluorescence spectrum measured by the fluorescence spectrum measuring unit 102 when the irradiation angle θ of the excitation light is large (when θ is close to 90 degrees). Peaks (first peak, second peak) are measured.

  Note that the first peak is defined as a peak on the shorter wavelength side than the second peak. Also, in both fluorescence spectra of FIG. 4A and FIG. 4B, the vertical axis value (relative light intensity) related to the fluorescence spectrum is normalized so that the height of the second peak is the same. It is carried out. Further, it is assumed that the center wavelength related to the first peak in FIG. 4A and the center wavelength related to the first peak in FIG. 4B are the same. Furthermore, it is assumed that the center wavelength related to the second peak in FIG. 4A and the center wavelength related to the second peak in FIG. 4B are the same.

  4B shows that the relative light intensity of the first peak with respect to the second peak is increased compared to FIG. 4A. In other words, it can be said that the first peak does not occur when the irradiation angle is small, but occurs when the irradiation angle is large. As described with reference to FIG. 2, as the excitation light irradiation angle θ increases, the excitation light intensity directly below the skin surface increases relatively. Therefore, the first peak is a layer relatively close to the skin surface. It can be seen that the second peak is fluorescence emitted from a relatively deep layer.

  As described above, the skin condition measurement apparatus 100 according to the present embodiment uses the property that the peak value of the fluorescence spectrum changes by changing the irradiation angle θ, so that the fluorescent substance existing only in the epidermis and dermis is quantified. Is possible. That is, the skin condition measuring apparatus 100 according to the present embodiment includes an angle changing mechanism that changes the irradiation angle of the excitation light with respect to the skin 103 in the configuration shown in FIG. The configuration will be described later.

  And the skin state measuring apparatus 100 can enlarge irradiation angle | corner (theta) of the excitation light with respect to a biological body by providing the angle change mechanism. When the irradiation angle θ is increased in this way, the propagation distance of the excitation light traveling in the living body becomes larger than when the irradiation angle θ is small. When the irradiation angle θ is increased, the intensity of the excitation light irradiated to the fluorescent substance (tryptophan AGEs or the like) existing only in the epidermis / dermis is greater than the fluorescent substance ( It becomes a value larger than the intensity of excitation light irradiated to collagen AGEs and the like.

  Thereby, in the fluorescence spectrum measured by the fluorescence spectrum measuring unit 102, the peak value corresponding to tryptophan AGEs or the like appears more clearly than the peak value corresponding to collagen AGEs.

  That is, as shown in FIG. 4A, when the irradiation angle θ is small, the peak value corresponding to tryptophan AGEs is hidden behind the peak value corresponding to collagen AGEs and does not appear clearly. This is because the intensity of the excitation light irradiated to the tryptophan AGEs present in the epidermis / dermis and the intensity of the excitation light irradiated to the collagen AGEs present in the blood vessel region are not so different.

  However, if the irradiation angle θ is set to a large value using the angle changing mechanism of the skin condition measuring apparatus 100, the peak value corresponding to tryptophan AGEs is smaller than that when the irradiation angle θ is small, as shown in FIG. Can be obtained.

  As described above, the skin condition measuring apparatus 100 according to the present embodiment measures the fluorescence spectrum by the fluorescence spectrum measuring unit 102 at each irradiation angle while changing the irradiation angle θ by the angle changing mechanism. Then, the fluorescence spectrum measuring unit 102 has a fluorescence spectrum that maximizes the peak value (peak intensity of a specific wavelength) of a fluorescent substance existing only in the epidermis / dermis such as tryptophan AGEs among the plurality of measured fluorescence spectra ( An irradiation angle θ (peak intensity generation irradiation angle) at which a peak intensity generation fluorescence spectrum) is obtained is determined. In this way, the skin condition measuring apparatus 100 can grasp the presence of tryptophan AGE and the like, and thus it is possible to quantify fluorescent substances existing only in the epidermis and dermis.

  The definition of the term “peak intensity at a specific wavelength” will be described more specifically. As shown in FIG. 4C, it is assumed that the valley 1 adjacent to the peak exists on the short wavelength side related to the fluorescence peak and the valley 2 adjacent to the peak exists on the long wavelength side related to the fluorescence peak. If the difference in light intensity between the fluorescence peak and the valley 1 adjacent to the peak is the intensity difference 1, and the difference in light intensity between the fluorescence peak and the valley 2 adjacent to the peak is the intensity difference 2, then the intensity difference 2 When the intensity difference is smaller than the intensity difference 1, the “peak intensity at the specific wavelength” indicates the intensity difference 2.

  That is, when there are troughs of fluorescence intensity on both the short wavelength side and the long wavelength side with respect to the fluorescence peak, the intensity difference between the fluorescence peak and the light intensity related to the trough on the short wavelength side, the fluorescence peak and the long Of the intensity differences between the light intensities associated with the valleys on the wavelength side, the smaller intensity difference corresponds to the “peak intensity at a specific wavelength”.

  In addition, when the valley does not exist on one side or both sides of the short wavelength side and the long wavelength side of the fluorescence peak, the light intensity of the valley is assumed to be zero.

  In addition, the present inventors also examined a method for measuring the distribution of the fluorescence intensity in the skin depth direction from the function between the displacement amount and the fluorescence intensity in the direction parallel to the skin surface. It was judged as difficult.

That is, as shown in FIG. 5, assuming that the irradiation angle of the excitation light is 80 degrees that is a practically realizable upper limit value, the skin has a refractive index of about 1.4. The excitation light is refracted at the interface. And from Snell's law, excitation light advances at an angle of about 45 degrees (= Sin ⁻¹ (sin 80 ° ÷ 1.4)) from the normal surface of the skin. For example, since the dermis / blood vessel interface exists in the vicinity of 2.2 mm from the skin surface, the irradiated region of the dermis (the region where the excitation light is irradiated) and the irradiated region of the blood vessel are approximately in the direction parallel to the skin surface. The distance is 2.2 mm.

  Furthermore, the fluorescence generated by irradiating the blood vessel region with the excitation light is irradiated in all directions and scattered in the skin structure before reaching the skin surface. The irradiation beam diameter has a finite size.

  As described above, in order to measure the depth direction distribution of the fluorescence intensity in a spatially separated direction parallel to the skin surface, for example, between the irradiated region of the dermis and the irradiated region of the blood vessel. The distance in the direction parallel to the skin surface between them must be taken into account. Furthermore, it is necessary to consider the scattering of fluorescence in the skin structure and the irradiation beam diameter. Therefore, it can be seen that it is extremely difficult to measure the distribution of the fluorescence intensity in the depth direction spatially separated in a direction parallel to the skin surface.

  In addition, in order to confirm that the relative intensity ratio in the first peak and the second peak has changed depending on the incident angle as shown in FIGS. 4A and 4B, the irradiation angle shown in FIG. In the relationship between θ and the excitation light intensity ratio, when two different angles (first irradiation angle and second irradiation angle) are selected as the irradiation angle, the excitation light intensity ratio corresponding to the first irradiation angle; The excitation light intensity ratio corresponding to the second irradiation angle needs to differ by at least 1.3 times. The value of 1.3 times is a value that can be changed according to the noise level at the time of fluorescence spectrum measurement.

  According to FIG. 2, the above conditions are satisfied if the two excitation light irradiation angles are different by 5 degrees or more, preferably 10 degrees or more, more preferably 20 degrees. It is good that they are different. However, when the irradiation angle is larger than 80 degrees, the value on the vertical axis in FIG. 2 shows a tendency to saturate, and the irradiation area of the excitation light is widened and is easily affected by unevenness of the skin surface and body hair. The measurement reproducibility is considered to be low. Therefore, it is desirable to set the irradiation angle to 80 degrees or less.

  In the present embodiment, the fluorescence spectrum showing the wavelength dependence of the fluorescence intensity is obtained as the measurement result in the fluorescence spectrum measurement unit 102, but other than this may be obtained as the measurement result. For example, a light intensity value obtained by measurement using a filter that selectively transmits the peak wavelength of a specific fluorescent substance and a photodetector (for example, a photodetector) that detects light intensity may be obtained as a measurement result. . It goes without saying that fluorescent substances existing only in the epidermis / dermis region can also be quantified by evaluation using such measurement results.

  FIG. 6A is a diagram showing a state in which excitation light is irradiated to the skin surface while diffusing, and FIG. 6B is a diagram in which excitation light is irradiated to the skin surface while being converged. FIG. The diffusion state as shown in FIG. 6A is realized by, for example, irradiating the skin with excitation light as it is from the end face of the optical fiber. Moreover, the convergence state as shown in FIG. 6B is realized, for example, by transmitting excitation light through a condenser lens.

  And in any case of Fig.6 (a) and FIG.6 (b), the irradiation angle of the excitation light with respect to the skin surface is distributed within the range of (theta) a- (theta) b. Both values of θa and θb can be easily grasped by performing geometric calculation from the structural parameters. If the average value of θa and θb is the center of the optical axis, and the angle formed by the center of the optical axis and the normal of the skin surface satisfies the condition related to θ described above, it exists in the epidermis or dermis region. Quantification of fluorescent substances can be performed.

  However, if the difference between θa and θb is increased, the accuracy of detecting the presence of the fluorescent substance existing in the epidermis or dermis region may be lowered. Therefore, it is desirable that the difference between θa and θb is small. More specifically, it is desirable that | θa−θb | ≦ 10 degrees. More desirably, | θa−θb | ≦ 5 degrees, and more desirably θa≈θb, that is, it is desirable that the excitation light is substantially parallel light. In order to make the excitation light substantially parallel light, a convex lens or the like for the purpose of collimation can be arranged in the optical path from the light source to a part of the skin irradiated with the excitation light.

  Further, when the diffusion state shown in FIG. 6A is realized by, for example, emitting the excitation light as it is from the end face of the optical fiber, the value of Δθ = | θa−θb | is NA (Numerical Aperture) = It can be calculated from sin Δθ / 2. Further, when the convergence state shown in FIG. 6B is realized by, for example, transmitting the excitation light through the condenser lens, the value of Δθ = | θa−θb | is the focal length f of the lens and the lens radius. r can be used to calculate tan (Δθ / 2) = r / f.

[2. Specific configuration example of angle changing mechanism)
Hereinafter, a specific configuration of the angle changing mechanism provided in the skin condition measuring apparatus 100 according to the present embodiment will be described. The skin condition measuring apparatus 100 shown in FIG. 1 schematically shows only the irradiation unit 101 and the fluorescence spectrum measuring unit 102, which are the main components of the apparatus. If a configuration other than the main configuration is understood, the specific configuration of the angle changing mechanism can be understood more clearly. Therefore, a specific configuration according to skin condition measuring apparatus 100 will be described with reference to FIGS. 7 (a) and 7 (b).

  First, FIG. 7A is a schematic diagram showing an overall apparatus configuration of the skin condition measuring apparatus 100. The measuring apparatus main body 113 including the light source 111 and the spectroscope 112 and the skin for measuring the skin condition are shown. The probe 114 in contact with the surface, the bundle fiber 115 optically connecting the measuring device main body 113 and the probe 114, and the spectrometer 112 are arranged so as to be electrically connected to display the measurement result. And display means 116. Further, both ends of the bundle fiber 115 are branched into two fibers, one being an excitation side optical fiber 117 and the other being a light receiving side optical fiber 118.

  FIG. 7B is a cross-sectional view of the probe 114 on a plane parallel to the paper surface. As shown in FIG. 7B, two arms 120 are connected to the housing 119 of the probe 114. Both of these two arms 120 rotate along a rail 123 processed inside the casing 114 with a straight line in the direction perpendicular to the paper passing through the approximate center of the area irradiated to a part 121 of the skin as the rotation center axis 122. It is a mechanism that can.

  An excitation side optical fiber 117 and a light reception side optical fiber 118 are mechanically fixed to each of the two arms 120. A collimating lens 125 is disposed at the tip of the excitation-side optical fiber 117, and a condenser lens 126 is disposed at the tip of the end surface of the light-receiving side optical fiber 118.

  7B, the excitation-side optical fiber 117, the arm 120 to which the fiber 117 is connected, and the collimating lens 125 correspond to the irradiation unit 101 shown in FIG. 7B, the light receiving side optical fiber 118, the arm 120 connected to the fiber 118, and the condenser lens 126 correspond to the fluorescence spectrum measuring unit 102 shown in FIG.

  With the above configuration, the excitation light 127 emitted from the excitation-side optical fiber 117 becomes substantially parallel light through the collimator lens and is irradiated onto a part 121 of the skin. Further, the fluorescence 128 generated by exciting the fluorescent substance in the skin by the excitation light is coupled to the end face of the light receiving side optical fiber 118 through the condenser lens 126.

  Moreover, the housing | casing 114 has the structure where the contact part 129 which contacts a part of skin protrudes. Further, as the light source 111, a near-ultraviolet LED light source having a central wavelength of 365 nm is used, and various optical fibers and lenses are all for near-ultraviolet light.

  With the above configuration, the skin condition measuring apparatus 100 changes the irradiation angle of the excitation light 127 to the part 121 of the skin by rotating the arm 120 connected to the excitation side optical fiber 117 along the rail 123. It can be done. That is, it can be said that the arm 120 and the rail 123 realize an angle changing mechanism that changes the irradiation angle of the excitation light to the skin.

  Thus, skin state measuring apparatus 100 can irradiate a part of skin with excitation light 127 at a non-zero irradiation angle by providing arm 120 and rail 123 as an angle changing mechanism. The skin condition measuring apparatus 100 is used to excite a part of the skin for 10 subjects who have applied a cream that reduces AGEs in the epidermis and dermis and 10 subjects who have not been applied the cream. The spectrum of fluorescence generated by irradiating light at a non-zero irradiation angle was measured (case A). As a result, a significantly smaller amount of AGEs was detected in the subject who applied the cream compared to the subject who did not apply the cream.

  On the other hand, when the fluorescence spectrum was measured in a state where the excitation light was applied to a part of the skin at an irradiation angle of approximately 0 degrees (referred to as case B), the subject who applied the cream and the cream were applied. There was no significant difference in the amount of AGEs among subjects who had not. In case B, not only AGEs (tryptophan AGEs) existing in the epidermis and dermis region of the skin but also the amount of AGEs (collagen AGEs etc.) in the blood vessel region are detected together, thereby reducing AGEs It can be said that the effect of the cream is not grasped.

  On the other hand, in case A, by irradiating the skin with the excitation light at a non-zero irradiation angle, that is, by irradiating the skin with the excitation light from an oblique direction, it is not affected by AGEs existing in the blood vessel region. The amount of fluorescent material (such as tryptophan AGEs) present only in the epidermis and dermis regions is detected. Thus, it can be said that the effect of reducing the AGEs by the cream can be clearly understood in Case A.

[3. Measurement of fluorescence spectra at two different irradiation angles]
In addition, the skin condition measuring apparatus 100 according to the present embodiment includes the angle changing mechanism as described above, thereby measuring the fluorescence spectrum at two different irradiation angles (first irradiation angle and second irradiation angle). This can be performed by the fluorescence spectrum measurement unit 102. Thus, the existing region of the unknown fluorescent material relative to the existing region of the known fluorescent material, based on the peak value of the fluorescence spectrum corresponding to the known fluorescent material and the magnitude relationship between the first irradiation angle and the second irradiation angle. The relative depth of can be determined. This point will be described in detail below.

  FIG. 8A shows a fluorescence spectrum (first emission angle) obtained by setting the irradiation angle of the excitation light to an irradiation angle (first irradiation angle) close to approximately 0 degrees using the angle changing mechanism of the skin condition measuring apparatus 100. It is a figure which shows a 1st fluorescence spectrum. FIG. 8B is a diagram showing a fluorescence spectrum (second fluorescence spectrum) obtained by setting the irradiation angle to a second irradiation angle larger than the first irradiation angle.

  In both FIG. 8 (a) and FIG. 8 (b), fluorescence peaks appear at two wavelengths. Of the two fluorescent peaks that appear in FIGS. 8 (a) and 8 (b), the second peak on the long wavelength side is a fluorescent peak corresponding to a known substance (collagen AGEs, etc.), and has a short wavelength. The first peak on the side is assumed to be a fluorescence peak corresponding to tryptophan AGEs or the like. Note that the fluorescence spectra shown in FIGS. 8A and 8B are normalized so that the values of the fluorescence peaks corresponding to the known substances are the same.

  8A and FIG. 8B, the fluorescence peak value of tryptophan AGEs in FIG. 8B is higher than the fluorescence peak value of tryptophan AGEs in FIG. 8A. It is getting bigger. From the relative comparison results of the fluorescence peak values, it can be said that for tryptophan AGEs, fluorescence having a greater intensity is generated by setting a large irradiation angle.

  That is, it can be said that tryptophan AGEs are present in a shallower region than the skin region where collagen AGEs are present. Since collagen AGEs are known to be fluorescent substances existing in the vascular region, it can be understood that a large amount of tryptophan AGEs are present in regions shallower than the vascular region, for example, the epidermis / dermis region.

  In this way, by comparing the fluorescence spectra obtained at two different irradiation angles with the fluorescence spectrum measurement unit 102, it is possible to determine the relative depth of the existing region of the unknown fluorescent material with respect to the existing region of the known fluorescent material. it can.

[4. (Configuration using excitation light with optimal wavelength for fluorescent substance)
Moreover, the accuracy of measuring the fluorescent substance in the skin can be further improved by using an excitation light source that emits excitation light having an optimum wavelength for exciting each of the various fluorescent substances contained in the skin. This point will be described more specifically below.

  First, FIG. 9 is a diagram showing a fluorescence spectrum measured by irradiating the test piece with excitation light having a wavelength of 365 nm (vertical irradiation) at an irradiation angle of approximately 0 degrees (vertical irradiation). In addition, the test piece is produced by artificially synthesizing tryptophan AGEs. Tryptophan AGEs were synthesized by mixing tryptophan (4.5 g / dl) and ribose (0.5 M) in a 1/15 M phosphate buffer and reacting in an incubator set at 40 ° C. is there.

  In the fluorescence spectrum shown in FIG. 9, the fluorescence peak of tryptophan AGEs appears in the wavelength region near 390 nm, although it is not clear. Further, a Raman peak of water appears in a wavelength region near 420 nm. The fluorescence peak of tryptophan AGEs does not appear clearly because the influence of the Raman peak of water greatly affects the fluorescence peak of tryptophan AGEs, and the fluorescence peak of tryptophan AGEs is hidden behind the Raman peak of water. It is considered to be a body.

  FIG. 10 is a diagram illustrating a fluorescence spectrum measured by irradiating a test piece with excitation light having a wavelength of 290 nm (vertical irradiation) in a state where the irradiation angle is approximately 0 degrees. In the fluorescence spectrum shown in FIG. 10, a tryptophan fluorescence peak clearly appears in the wavelength region near 350 nm. In addition, a fluorescence peak of tryptophan AGEs clearly appears in the wavelength region near 390 nm.

  9 and 10 are both measured using a commercially available fluorometer (manufactured by Horiba, Ltd.).

  As is clear from the comparison between the fluorescence spectrum shown in FIG. 9 and the fluorescence spectrum shown in FIG. 10, the fluorescence peak of tryptophan AGEs is clearer when the wavelength of the excitation light is 290 nm than when the wavelength of excitation light is 365 nm. Has appeared. That is, it can be said that excitation light having a wavelength of 290 nm is suitable for exciting tryptophan AGEs. For fluorescent substances other than tryptophan AGEs, such as collagen AGEs, a clear fluorescent peak appears by using excitation light having a wavelength of 365 nm, for example.

  Thus, each fluorescent substance contained in the skin has a wavelength of excitation light suitable for causing each fluorescent peak to appear. Therefore, as shown in FIG. 11A, when the irradiation angle θ is as large as about 60 degrees, excitation light having a wavelength of 365 nm is guided from the light source 111 to the probe 114 and irradiated as shown in FIG. 11B. When the angle θ is about 60 degrees and large, excitation light having a wavelength of 290 nm is guided from the light source 111 to the probe 114.

  When the fluorescence spectrum is measured by changing the wavelength of the excitation light in this way, as shown in FIG. 11A, when the wavelength of the excitation light is 365 nm, the fluorescence peak of collagen AGEs and the fluorescence peak of tryptophan AGEs are obtained. Both appear clearly. On the other hand, when the wavelength of the excitation light is 290 nm, only the fluorescence peak of tryptophan AGEs appears as shown in FIG.

  Therefore, when measuring the fluorescence spectrum by increasing the irradiation angle θ, if the skin is irradiated with excitation light having a wavelength suitable for exciting fluorescent substances (tryptophan AGEs, etc.) present in a large amount in the epidermis / dermis region, A fluorescence spectrum in which the fluorescence peak of the fluorescent substance clearly appears can be obtained. Thereby, the quantitative determination of the fluorescent substance existing only in the epidermis and dermis regions can be performed more accurately.

  In order to emit excitation light having a plurality of different wavelengths in the light source, various configurations can be employed. For example, a tube type such as a halogen or xenon light source, an LED, an LD, or the like can be used.

  And the relationship of the relative depth between different fluorescent substances can also be grasped | ascertained from the relationship between the fluorescence spectrum and irradiation angle which are obtained about each of several different wavelengths emitted from a light source. This will be described below.

  First, as shown in FIG. 12A, it is assumed that a fluorescence spectrum having a fluorescence center in the vicinity of 460 nm is obtained by irradiating the skin with excitation light having a wavelength of 365 nm (first wavelength). Further, as shown in FIG. 12B, it is assumed that a fluorescence spectrum having a fluorescence center near 350 nm is obtained by irradiating the skin with excitation light having a wavelength of 290 nm (second wavelength).

  In addition, it is thought that the fluorescence spectrum shown to Fig.12 (a) is a fluorescence spectrum corresponding to collagen AGEs. Further, the fluorescence spectrum shown in FIG. 12B is considered to be a fluorescence spectrum corresponding to tryptophan AGEs.

  Further, FIG. 12C shows how the peak intensity of the fluorescence spectrum shown in FIG. 12A changes when the irradiation angle is changed by the angle changing mechanism provided in the skin measuring apparatus 100. It is a graph (1st correlation). FIG. 12D shows how the peak intensity of the fluorescence spectrum shown in FIG. 12B changes when the irradiation angle is changed by the angle changing mechanism provided in the skin measuring apparatus 100. It is a graph (2nd correlation).

  As can be seen from a relative comparison between the graph shown in FIG. 12C and the graph shown in FIG. 12D, in the graph shown in FIG. 12C, the peak intensity increases sharply when the irradiation angle is increased. However, in the graph shown in FIG. 12 (d), the peak intensity gradually decreases as the irradiation angle is increased. As described above, the difference in the shape in which the peak intensity decreases between the graph shown in FIG. 12C and the graph shown in FIG. 12D is because the tryptophan AGEs are shallower than the collagen AGEs (epidermis / dermis). This is probably because it exists in the area.

  As described above, the procedure for grasping the relative depth relationship between different fluorescent materials using the property that the correlation between the peak intensity and the irradiation angle is different depending on the fluorescent material is described below. It is as follows.

  That is, assuming that the depth of the region in which the fluorescent substance is distributed in the skin is sufficiently thin, the excitation light intensity at the skin surface is A, the irradiation angle of the excitation light is θ1, the refraction angle is θ2, and the absorption coefficient at the excitation wavelength λ Is α (λ), the excitation light intensity at the depth T of the distribution region can be expressed by the following equation.

(The irradiation angle θ1, the refraction angle θ2, and the depth T are shown in FIG. 13)
Further, θ1 and θ2 can be expressed by the following equation using the refractive index n in the skin from Snell's law.

  Considering the above equation, as for the graph showing the correlation between the peak intensity and the irradiation angle, as the value of α (λ) or T increases, the value of the peak intensity at a smaller irradiation angle θ as shown in FIG. Becomes asymptotic to the horizontal axis. In FIG. 14, the graph relating to discrete 1 to discrete 4 is obtained by simulation in which the absorption coefficient α and the depth T are set as follows.

discrete1: α = 35 [/ cm], T = 0.22 [cm]
discrete2: α = 50 [/ cm], T = 0.22 [cm]
discrete3: α = 70 [/ cm], T = 0.22 [cm]
discrete4: α = 100 [/ cm], T = 0.22 [cm]
Therefore, the absorption coefficient α (λ) with respect to the excitation wavelength λ is referred to from the literature value, and the actual measurement results relating to the relationship between the peak intensity of the fluorescence spectrum and the irradiation angle are expressed in the above [Expression 5] and [Expression 6] If the depth T is obtained so as to coincide with the simulation result performed based on this, the depth relating to the fluorescent substance to be measured can be grasped.

  For example, when the graph shown in FIG. 12C is compared with the graph shown in FIG. 12D, the graph shown in FIG. 12C is smaller in irradiation than the graph shown in FIG. The value of the peak intensity at the angle is asymptotic to the horizontal axis. This is because the depth T of the fluorescent substance (collagen AGEs) corresponding to the graph of FIG. 12C is larger than the depth T of the fluorescent substance (tryptophan AGEs) corresponding to the graph of FIG. I mean. In other words, when the graph of FIG. 12C is compared with the graph of FIG. 12D, it can be understood that tryptophan AGEs are present in a shallower region (skin / dermis region) than collagen AGEs.

  In this way, by comparing the relationship between the fluorescence spectrum obtained for each of a plurality of different wavelengths emitted from the light source and the irradiation angle in the fluorescence spectrum measurement unit 102, the relative comparison between the different fluorescent substances is performed. It is also possible to grasp the relationship of depth.

[5. Difference between two fluorescence spectra]
Furthermore, the skin condition measuring apparatus 100 of the present embodiment may obtain fluorescence spectra for each of two different irradiation angles and subtract one fluorescence spectrum from the other fluorescence spectrum. As a result, a fluorescence spectrum of a fluorescent substance existing at a specific depth and having a reduced influence of the fluorescent substance existing in another region can be obtained as a difference spectrum. This point will be described more specifically below.

  FIG. 15A is a diagram showing a measured fluorescence spectrum (first fluorescence spectrum) after setting the irradiation angle θ to almost 0 degrees using the angle changing mechanism of the skin condition measuring apparatus 100 and setting it to a small value. is there. FIG. 15B is a diagram showing a fluorescence spectrum (second fluorescence spectrum) measured after setting the irradiation angle θ not to 0 degrees but to a somewhat large value (about 60 degrees).

  When the fluorescence spectrum shown in FIG. 15 (a) is compared with the fluorescence spectrum shown in FIG. 15 (b), two peaks of the first peak and the second peak appear in FIG. 15 (a). Also, in FIG. 15B, two peaks of the first peak and the second peak appear, but the value of the second peak in FIG. 15B is the same as in FIG. It is much smaller than the value of the second peak. Note that the fluorescence spectra according to FIG. 15A and FIG. 15B are normalized so that the values of the first peaks are the same.

  From the above measurement results, the first peak is mainly fluorescence from the fluorescent substance distributed more than the skin surface, and the second peak is mainly from the fluorescent substance distributed more deeply from the skin surface. It turns out that it is fluorescence.

  For example, assume that the second peak is a fluorescent peak corresponding to late saccharification reaction products (AGEs), and the first peak is a fluorescent peak corresponding to an unknown substance. In this case, since AGEs are known to be distributed in any region from the epidermis region to the blood vessel region, the fluorescent material that is the source of the second peak is at least a position deeper than the average distribution depth of AGEs. It can be seen that That is, it can be seen that a large amount of the fluorescent material that is the source of the second peak is distributed in the blood vessel or a position close thereto.

  FIG. 15C is a diagram showing a difference spectrum obtained by subtracting the fluorescence spectrum shown in FIG. 15B from the fluorescence spectrum shown in FIG. By subtracting the two fluorescence spectra in this way, information on the fluorescent substance existing between the skin surface and the blood vessel is canceled. Therefore, it can be said that the difference spectrum shown in FIG. 15C mainly depends on the density of the fluorescent substance existing in the blood vessel. By using such a difference spectrum, the density of the substance present in the blood vessel can be accurately measured.

  In addition, as an application example of concentration measurement relating to a fluorescent substance in blood, measurement of AGEs in blood can be mentioned. Measuring AGEs in the blood in this way is very useful in that early detection and progress of diabetes can be grasped.

  That is, when oxidative stress is applied in an environment where an abnormal amount of sugar or lipid is present in the blood, the protein reacts with the sugar or lipid to produce a glycated protein. When this further repeats dehydration and condensation, AGEs are generated, and the generated AGEs deposit and invade the blood vessel wall, or act on macrophages that are part of the immune system to release cytokines, which are a type of protein. Along with this, inflammation of blood vessels and arteriosclerosis develop, and it is said that when such symptoms progress, diabetes is induced. Therefore, it can be said that it is very useful to measure AGEs in blood and to detect early detection or progress of diabetes.

  FIG. 15C shows the result of canceling the information on the fluorescent substance existing between the skin surface and the blood vessel. However, the present invention is not limited to this, and as long as the fluorescent substance is distributed in a region shallower than the region having a depth of 0.2 mm from the skin surface, FIGS. The information can be canceled by a method similar to the method of subtracting the fluorescence spectrum described using c).

  That is, the epidermis layer is present in a region shallower than the region having a depth of 0.2 mm from the skin surface, and the dermis layer is present in a region deeper than the region having a depth of 0.2 mm from the skin surface. doing. For example, the fluorescence spectrum relating to fluorescent substances such as AGEs, hydroxyproline, riboflavin, nicotinamide adenine dinucleotide (NADH), protoporphyrin, tyrosine, tryptophan, and elastin in the dermis layer is an angle changing mechanism of the skin condition measuring apparatus 100. Can be measured by irradiating excitation light with the irradiation angle set to about 60 degrees.

  Then, the fluorescence spectrum measured in this way is differentiated from the fluorescence spectrum measured by setting the irradiation angle to approximately 0 degrees, so that the fluorescent substance distributed in the region shallower than the region of 0.2 mm can be obtained. Such a fluorescence spectrum can be canceled.

  In the fluorescence peak shown in FIG. 15B, the second peak clearly appears as a peak having a certain peak value. Therefore, when the fluorescence spectrum shown in FIG. 15B is subtracted from the fluorescence spectrum shown in FIG. 15A, the peak value related to the second peak shown in FIG. It is reduced by an amount corresponding to the peak value related to the second peak. Therefore, in the difference spectrum shown in FIG. 15C, there is a possibility that the peak value related to the second peak does not appear clearly.

  In order to reduce this possibility and clearly grasp the existence of the second peak in the difference spectrum, the wavelength of the excitation light when the irradiation angle is small and the wavelength of the excitation light when the irradiation angle is large Change it. That is, when the irradiation angle is as small as 0 degree, the skin is irradiated with excitation light having a wavelength suitable for exciting the fluorescent substance existing in the blood vessel region, while the irradiation angle θ is not a large value (60 degrees). In this case, the skin may be irradiated with excitation light having a wavelength suitable for excitation of the fluorescent substance existing only in the epidermis and dermis regions.

  For example, as shown in FIGS. 11A and 11B, the skin may be irradiated with excitation light having a wavelength of 365 nm and excitation light having a wavelength of 290 nm. As a result, as shown in FIG. 11 (a), a fluorescence spectrum in which fluorescence peaks such as collagen AGEs that are present in a large amount in the blood vessel region clearly appear can be obtained. On the other hand, as shown in FIG. 11 (b), it is possible to obtain a fluorescence spectrum in which the fluorescence peak of tryptophan AGEs present only in the epidermis and dermis regions appears clearly.

  Therefore, by subtracting the fluorescence spectrum shown in FIG. 11 (b) from the fluorescence spectrum shown in FIG. 11 (a), a difference spectrum as shown in FIG. 16 can be obtained, and the influence of the epidermis and dermis regions can be accurately removed. In addition, a fluorescence spectrum corresponding only to the fluorescent substance existing in the blood vessel region can be obtained. Thereby, the quantitative determination of the fluorescent substance existing in the blood vessel region can be performed more accurately.

[6. Supplementary items regarding physical configuration of skin condition measuring device)
As described above, the skin condition measuring apparatus 100 has various effects by including an angle changing mechanism. In addition, since the skin condition measuring apparatus 100 has various physical structural features in addition to the angle changing mechanism, it will be described below.

  First, the optical fiber used for the skin condition measuring apparatus 100 will be described. As shown in FIG. 7B, the excitation side optical fiber 117 and the light receiving side optical fiber 118 used in the skin condition measuring apparatus 100 are both fixed to the arm 120 inside the probe 114 and movable together with the arm 120. It has a structure to do.

  Therefore, it is desirable to select the excitation-side optical fiber 117 and the light-receiving-side optical fiber 118 having a small radius of curvature so as not to break inside the skin condition measuring apparatus 100.

  However, the radius of curvature is approximately inversely proportional to the cladding diameter and core diameter, and the core diameter is approximately proportional to the coupling efficiency from the light source 111 to the excitation-side optical fiber 117 and the coupling efficiency of fluorescence to the light-receiving side optical fiber 118. is there. That is, since there is a trade-off relationship between a small radius of curvature and an increase in fluorescence detection intensity, there is an optimum value for the radius of curvature of the optical fiber. Specifically, it is desirable that the core diameter is 50 to 1,000 μm and the cladding diameter is 60 to 1,200 μm.

  Moreover, as shown in FIG.7 (b), the contact part 129 with the skin in the skin state measuring apparatus 100 comprises the substantially single plane. It is desirable that the measurement is performed in a state where the skin surface coincides with the plane formed by the contact portion 129. However, if the area of the contact portion 129 is small, the area constituting the plane also decreases, and the skin surface is reduced. Measurement in an inclined state is allowed.

  Furthermore, when the probe 114 is pressed against the skin, the skin swells inside the contact portion 129, and therefore the irradiation angle of the excitation light to the skin surface changes every measurement, which may lead to a decrease in measurement reproducibility. is there. For this reason, it is desirable that the area of the contact portion 129 has an area of at least a circular shape having a radius of 1 cm. More preferably, the area of the contact portion 129 is preferably a circular area having a radius of 2 cm or more. However, if the area of the contact portion 129 is too large, there is a problem that the measurement target region becomes unclear. Therefore, the area of the contact portion 129 is desirably an area having a radius of 10 cm or less.

  In addition, in FIG.7 (b), although excitation light is described as substantially parallel light, this invention is not limited to this. That is, the excitation light may not be substantially parallel light. For example, even if the excitation light is convergent light or divergent light, the center of the optical axis of the lens that converges or diverges the excitation light and the normal of the skin surface. By changing the angle with respect to the direction (irradiation angle), as described above, the fluorescent substance relating to a specific region of the skin can be selectively quantified.

  However, as described above, the excitation light is more preferably parallel light. In addition, the light emitted from the end face of the excitation-side optical fiber 117 may be used as excitation light without using the collimating lens 125. In this case, the excitation-side optical fiber 117 has a NA to reduce the divergence angle of the excitation light. It is desirable to use one having a low value.

  In FIG. 7B, the light receiving side optical fiber 118 is disposed in the normal direction of the skin surface, but it is not always necessary. That is, the light receiving side optical fiber 118 may be arranged so as to be inclined with respect to the normal direction of the skin surface. In FIG. 7B, the arm 120 to which the light receiving side optical fiber 118 and the condensing lens 126 are connected is movable. However, this is not always necessary, and is manufactured integrally with the probe housing 119. May be.

  In FIG. 7B, the fluorescence is connected to the light receiving side optical fiber 118 using the condensing lens 126, but the condensing lens 126 is not essential for the skin condition measuring apparatus 100. For example, the end face of the light receiving side optical fiber 118 may be arranged near the skin surface so that the fluorescence is directly coupled to the end face of the light receiving side optical fiber 118.

  Further, in FIG. 7B, the arm 120 has a structure in which the collimator lens 125 and the condenser lens 126 are continuously movable around the rotation center axis 122, but this is not essential. For example, the collimating lens 125 and the condensing lens 126 may be configured to be fixed to the probe housing at discrete angles.

[7. Variation of angle change mechanism)
FIG. 17 is a view for explaining a modification of the angle changing mechanism according to the measuring apparatus of the present invention. The overall apparatus configuration is the same as that shown in FIG.

  First, an excitation side lens holder 202 and a light receiving side lens holder 203 are fixed to the probe housing 201. A collimating lens (not shown) that incorporates excitation light guided from the excitation-side optical fiber 204 as convergent light is incorporated inside the excitation-side lens holder 202. In addition, a condensing lens (not shown) for condensing the fluorescence generated by the irradiation of excitation light is incorporated in the light receiving side lens holder 203.

  An excitation side optical fiber 204 is connected to the excitation side lens holder 202, and a light reception side optical fiber 205 is connected to the light reception side lens holder 203. Then, the excitation light 206 emitted from the excitation side lens holder 202 is applied to the movable mirror 208 arranged to be inclined with respect to the optical axis of the excitation light and the skin surface 207, so that the irradiation angle is not 0 degrees. In this way, the skin surface is irradiated.

  In the configuration shown in FIG. 17, the excitation side lens folder 202, the excitation side optical fiber 204, and the movable mirror 208 correspond to the irradiation unit 101 in FIG. Further, the light receiving side lens folder 203 and the light receiving side optical fiber 205 correspond to the fluorescence spectrum measuring unit 102 in FIG. A mechanism in which the movable mirror 208 rotates about the rotation shaft 209 is employed as an angle changing mechanism for changing the irradiation angle of the excitation light to the skin.

  The movable mirror 208 has a structure in which degrees of freedom are provided in the rotation direction around the rotation axis 209 and the optical axis direction of the excitation side lens holder 202. The rotation angle of the movable mirror 208 is determined by the irradiation angle of the excitation light on the skin surface. That is, when the irradiation angle of the excitation light with respect to the normal direction of the skin surface is θ, the movable mirror 208 may be set so as to be inclined by θ / 2 with respect to the normal direction of the skin surface. It can be determined by geometric optics calculation.

  Further, with respect to the rotation center axis of the movable mirror 208, the position of the excitation light in the optical axis direction is determined so that the excitation light is irradiated to the approximate center of the contact portion 210 with the skin surface of the probe housing 201. For example, when the irradiation angle of the excitation light to the skin surface 207 is θ, it is movable at the intersection of a straight line inclined by θ in the optical plane from the normal direction of the skin surface and the optical axis of the excitation side lens holder 206. The rotation center axis of the mirror 208 is determined so as to be arranged.

  Then, according to the probe configured as shown in FIG. 17, the irradiation angle of the excitation light with respect to the skin surface 207 can be changed by rotating the movable mirror 208 with respect to the rotation center axis 209. Therefore, the fluorescence spectrum measured by the skin condition measuring apparatus 100 shown in FIGS. 7A and 7B can be obtained by the skin condition measuring apparatus having the configuration shown in FIG.

  In FIG. 17, the excitation light is described as convergent light, but the present invention is not limited to this. That is, even if the excitation light is parallel light or divergent light, by changing the angle between the optical axis center of the lens that makes the excitation light parallel light or divergent light and the normal direction of the skin surface, The quantitative determination of the fluorescent substance relating to a specific region of the skin can be performed selectively.

  However, as described above, the excitation light is more preferably parallel light. The light emitted from the end face of the fiber may be used as the excitation light without using a lens. In this case, an excitation side optical fiber having a low NA may be used so that the divergence angle of the excitation light is reduced. desirable.

  In FIG. 17, the light-receiving side lens holder 203 is arranged so that the central axis of the light-receiving side lens holder 203 coincides with the normal direction of the skin surface, but this is not always necessary. For example, the light receiving side lens holder 203 may be arranged so that the central axis of the light receiving side lens holder 203 is inclined with respect to the normal direction of the skin surface.

  Further, in FIG. 17, fluorescence is connected to the light receiving side optical fiber 205 using a condensing lens provided inside the light receiving side lens holder 203, but the condensing lens is not necessarily required. For example, the end face of the light receiving side optical fiber 205 may be disposed in the vicinity of the skin surface 207 so that the fluorescence is directly coupled to the end face of the light receiving side optical fiber 205.

[8. (Configuration in which the fluorescence spectrum measurement unit is provided in the probe housing)
Further, as a modification of the skin condition measuring apparatus 100, a fluorescence spectrum measuring unit can be provided in the probe housing, and will be described with reference to FIG.

  As shown in FIG. 18, an LED light source 302, a collimator lens 303, and a movable mirror 304 are arranged inside the probe housing 301. With these configurations, the excitation light emitted from the LED light source 302 is reflected by the movable mirror 304 after passing through the collimating lens 303, and is applied to the part 306 of the skin that contacts at the contact portion 305. Further, the fluorescence emitted from the part 306 of the skin is converted into parallel light through the condenser lens 307 and then introduced into the half mirror 308.

  The half mirror 308 divides the fluorescent power into two parts, and one of the divided fluorescent powers is introduced into the filter 309 and the photodiode 311. The other of the divided fluorescence power is introduced into the filter 310 and the photodiode 312. The filters 309 and 310 are designed to selectively transmit fluorescence having different wavelengths as centers.

  In the configuration example shown in FIG. 18, the irradiation unit including the LED light source 302 and the fluorescence spectrum measurement unit including the filters 309 and 310 and the photodiodes 311 and 312 are all incorporated in the probe housing 301. It is characterized by the structure.

  As with the movable mirror 208 shown in FIG. 17, the movable mirror 304 has a structure in which degrees of freedom are provided in the rotation direction around the rotation axis 313 and the optical axis direction of the excitation light. The rotation angle of the movable mirror 304 is determined by the irradiation angle of the excitation light to the skin surface. That is, when the irradiation angle of the excitation light with respect to the normal direction of the skin surface is θ, the movable mirror 304 may be set to be inclined by θ / 2 with respect to the normal direction of the skin surface. It can be determined by geometric optics calculation.

  As for the rotation center axis of the movable mirror 304, the position of the excitation light in the optical axis direction is determined so that the excitation light is irradiated to the approximate center of the contact portion 305 of the probe housing 301 with the skin surface. For example, if the irradiation angle of the excitation light with respect to the skin surface 306 is θ, the movable mirror 304 is located at the intersection of the straight line inclined by θ in the optical surface from the normal direction of the skin surface and the optical axis of the excitation light. The rotation center axis is determined to be arranged.

  Further, the center wavelength of the fluorescence spectrum transmitted by the filter 309 in the configuration example shown in FIG. 18 is λ1, and the center wavelength of the fluorescence spectrum transmitted by the filter 310 is λ2. The electrical signal intensities obtained from the photodiodes 311 and 312 at the irradiation angle θ1 are A1 and A2, respectively, and the electrical signals obtained from the photodiodes 311 and 312 at the irradiation angle θ2 (> θ1), respectively. The strengths are B1 and B2, respectively.

  In this case, if A2 / A1> B2 / B1, the fluorescent material that generates fluorescence transmitted by the filter 310 is distributed at a deeper position than the fluorescent material that generates fluorescence transmitted by the filter 309. It can be said that. If A2 / A1 <B2 / B1, the fluorescent material that generates fluorescence transmitted through the filter 310 is distributed at a shallower position than the light-emitting material that generates fluorescence transmitted through the filter 310. I can say that. Furthermore, if A2 / A1≈B2 / B1, the fluorescent material that generates fluorescence transmitted by the filter 310 is distributed at substantially the same depth as the fluorescent material that generates fluorescence transmitted by the filter 309. Judgment can be made.

[9. Comparison of measured fluorescence spectrum and database)
FIG. 19A and FIG. 19B are diagrams showing a modification of the skin condition measuring apparatus. As shown in FIG. 19A, a skin condition measuring apparatus 400 includes a main body 403 including a light source 401 and a spectroscope 402, a probe 404 that is in contact with the skin surface for measurement, and a main body 403 and a probe 404. A bundle fiber 405 that is optically connected, and a display unit 406 that is electrically connected to the spectroscope 402 of the main body 403 and displays a measurement result.

  Further, both ends of the bundle fiber 405 are branched into two fibers, one being an excitation side optical fiber 407 and the other being a light receiving side optical fiber 408. Further, the display unit 406 includes a comparison unit 411 that compares the fluorescence spectrum 409 that is a measurement result of the spectrometer 402 with data registered in the database 410 (details will be described later), and a display unit 412 that displays the comparison result. Is included.

  FIG. 19B is a cross-sectional view of the probe 404 in a plane parallel to the paper surface. As shown in FIG. 19B, an excitation side optical fiber 414 and a fluorescence side optical fiber 415 are introduced into the probe housing 413. Then, the excitation light emitted from the excitation-side optical fiber 414 is irradiated through the collimator lens 416 to a part of the skin 418 that has contacted the contact part 417. Further, the fluorescence emitted by the irradiation of the excitation light is introduced into the light receiving side optical fiber 415 disposed in the vicinity of a part of the skin (within 5 mm from the skin) without using a condensing lens. Then, it is introduced into a spectroscope 402 provided inside the main body 403.

  The skin condition measuring apparatus 400 shown in FIG. 19A is characterized in that the fluorescence spectrum obtained as a result of the measurement is compared with data registered in the database 410. In the database 410, data related to the fluorescence spectrum measured by causing the excitation light to enter the skin surface of a large number of people perpendicularly is registered. More specifically, in the data registered in the database 410, information on gender, age, height, weight, ethnicity, skin melanin content, etc. is stored in a state associated with each measurement subject. Yes.

  Then, by comparing the data registered in the database 410 with the measured fluorescence spectrum in this way, the depth of the fluorescent material that becomes the light emission source of a plurality of fluorescence peaks existing in the measured fluorescence spectrum is determined. , Can be relatively grasped.

  The configuration of the probe shown in FIG. 19B fixes the irradiation angle of the excitation light to the skin. Of course, the irradiation angle as shown in FIGS. 7B, 17 and 18 is used. The fluorescence spectrum measured using the changeable probe may be compared with data registered in the database 410.

  The measuring device of the present invention includes a light source that irradiates a part of the skin with light and a light detection unit that detects light generated by irradiating the part of the skin with light. At least a step of measuring at a first angle that a non-zero angle is formed between a direction of light irradiated to the part and a vertical direction of a part of the skin, and obtaining a first measurement result from the skin surface. It can also be expressed as a measuring device that obtains information up to depth.

  Further, the predetermined depth is preferably 0.2 mm or more.

  Furthermore, the measurement apparatus includes at least a step of measuring the second angle at a second angle different from the first angle to obtain a second measurement result, and from the first measurement result and the second measurement result, It is preferable to obtain depth direction distribution information of the skin state.

  Furthermore, the wavelength of the light emitted from the light source is preferably within a range in which the late saccharification reaction product can be detected.

  Furthermore, it is preferable that the measuring apparatus includes a surface that is in contact with a part of the skin and has an area equal to or larger than a circular shape having a radius of 1 cm substantially parallel to the contact portion.

  Furthermore, the measuring apparatus preferably includes at least one convex lens in an optical path from the light source to a part of the skin irradiated with light.

  Furthermore, it is preferable that both the first measurement result and the second measurement result are wavelength dependency of light intensity.

  Furthermore, it is preferable that the measuring apparatus includes a mechanism that can change an angle formed by a direction of light applied to a part of the skin and a vertical direction of a part of the skin.

  Furthermore, it is preferable that the first angle and the second angle differ by 10 degrees or more.

  Further, the measuring device may be any one centered on the same wavelength in the wavelength dependence of the light intensity as the first measurement result and the wavelength dependence of the light intensity as the second measurement result. It is preferable to obtain depth direction distribution information of the skin state by performing normalization by peak intensity and comparing other peak intensities.

  Furthermore, it is preferable that the depth direction distribution information of the skin state is a concentration of the fluorescent substance in a region at least 0.2 mm deeper than the skin surface. Furthermore, the region is preferably inside a blood vessel.

  The measurement apparatus of the present invention further includes a light source that irradiates a part of the skin with light and a light detection unit that detects light generated by irradiating the part of the skin with light. A mechanism in which an angle formed by a direction of light applied to the part and a vertical direction of a part of the skin is fixed, and includes at least a step of measuring the angle at a first angle to obtain a first measurement result The first measurement result and the database result measured at an angle different from the first angle may be compared to express the skin state depth direction distribution information.

  Furthermore, the measurement method of the present invention includes a step of irradiating a part of the skin with light, a step of detecting light generated by irradiating the part of the skin with light, and irradiating a part of the skin. At least a step of obtaining a first measurement result by measuring at a first angle that a non-zero angle is formed between a direction of the emitted light and a vertical direction of the part of the skin, and includes a step from the skin surface to a predetermined depth. It can also be expressed as a method of obtaining information.

  Furthermore, the measurement method of the present invention includes the step of obtaining the second measurement result by measuring the second angle different from the first angle, and the first measurement result and the second measurement result, It preferably includes obtaining depth direction distribution information of the skin condition.

  According to the present invention, since fluorescent substances existing only in the epidermis and dermis can be quantified, it can be applied to beauty / health appliances for preventing wrinkles, dullness, etc., and to grasp the early detection and progress of diabetes. Can also be used.

100 Skin condition measuring device (measuring device)
101 Irradiation unit 102 Fluorescence spectrum measurement unit 111 Light source 120 Arm (angle changing mechanism)
123 rail (angle changing mechanism)
125 collimating lens

Claims (10)

An irradiation unit for irradiating the living body with excitation light guided from an excitation light source;
A fluorescence spectrum measuring unit for measuring a fluorescence spectrum related to fluorescence generated by irradiation of the excitation light;
An angle changing mechanism that changes an irradiation angle of the excitation light to the living body. The fluorescence spectrum measuring unit is
While measuring the fluorescence spectrum for each of a plurality of irradiation angles set by changing the irradiation angle by the angle change mechanism,
Obtain the fluorescence spectrum that maximizes the peak intensity of a specific wavelength among the measured fluorescence spectra as the peak intensity generation fluorescence spectrum,
The measurement apparatus according to claim 1, wherein an irradiation angle at which the peak intensity generation fluorescence spectrum is obtained is determined as a peak intensity generation irradiation angle. When the irradiation angle is defined as the angle formed by the normal direction of the surface irradiated with the excitation light in the living body and the irradiation direction of the excitation light,
The intensity of the specific wavelength relating to the peak intensity generation fluorescence spectrum does not occur when the irradiation angle is small, but corresponds to the intensity of a peak generated when the irradiation angle is large. 2. The measuring apparatus according to 2. The fluorescence spectrum measuring unit is
A fluorescence spectrum of fluorescence generated when the excitation light is irradiated on the living body at a first irradiation angle, is measured as a first fluorescence spectrum;
Measuring the fluorescence spectrum of the fluorescence generated when the living body is irradiated with the excitation light at a second irradiation angle different from the first irradiation angle, as a second fluorescence spectrum;
The measuring apparatus according to claim 1, wherein the first fluorescence spectrum and the second fluorescence spectrum are relatively compared. The fluorescence spectrum measuring unit is
When the wavelength at which the fluorescence intensity in the first fluorescence spectrum exhibits a peak value and the wavelength at which the fluorescence intensity in the second fluorescence spectrum exhibits a peak value are present in the same wavelength region, the first fluorescence spectrum and the first fluorescence spectrum The measurement apparatus according to claim 4, wherein a difference fluorescence spectrum obtained by subtracting two fluorescence spectra is obtained.   The measurement apparatus according to claim 1, further comprising a light source that emits excitation light having a plurality of different wavelengths as the excitation light source. When the plurality of different wavelengths of the excitation light emitted by the excitation light source are the first wavelength and the second wavelength,
The fluorescence spectrum measuring unit is
A first correlation which is a correlation between the irradiation angle of the excitation light according to the first wavelength and the intensity of fluorescence generated by the irradiation of the excitation light;
The measurement according to claim 6, wherein a relative comparison is made between an irradiation angle of the excitation light related to the second wavelength and a second correlation that is a correlation between the intensity of fluorescence generated by the irradiation of the excitation light. apparatus.   The measurement apparatus according to claim 1, wherein the excitation light has a wavelength range suitable for measuring AGEs (Advanced Glycation Endproducts).   The measuring apparatus according to claim 1, further comprising a collimating lens in an optical path from the excitation light source to the living body. An irradiation step of irradiating a living body with excitation light guided from an excitation light source;
A measurement method comprising a fluorescence spectrum measurement step of measuring a fluorescence spectrum related to fluorescence generated by irradiation of the excitation light for each of a plurality of irradiation angles while changing the irradiation angle of the excitation light to the living body. .

Images