JP5818038B2 - Concentration determination apparatus, concentration determination method, and program - Google Patents

Description

  The present invention relates to a concentration quantification apparatus, a concentration quantification method, and a program for non-invasively and accurately quantifying the concentration of a target component in an arbitrary layer among observation targets composed of a plurality of light scattering medium layers. It is.

In recent years, Japan is in the age of satiety, and the number of diabetic patients continues to increase every year. For this reason, the number of patients with diabetic nephritis will continue to increase every year. As a result, the number of patients with chronic renal failure continues to increase by 10,000 each year, and the number of patients exceeds 280,000.
On the other hand, with the arrival of an aging society, the importance of metabolic rate management in individuals is rapidly increasing in response to increasing demand for preventive medicine. Among them, blood glucose level measurement is known to be able to understand the reaction of glucose metabolism by measuring the blood glucose level before and after meals, and by evaluating the reaction of glucose metabolism at the very early stage of diabetes, Early treatment based on early diagnosis becomes possible.

Conventionally, the blood sugar level is measured by collecting blood from a vein such as an arm or a fingertip and measuring the enzyme activity for glucose in the blood. However, such a blood glucose level measurement method has various problems such as complicated blood collection, pain associated with blood collection, and risk of infection.
In addition, as a method for continuously measuring blood glucose level, an instrument that continuously measures glucose corresponding to blood glucose level with a needle inserted into a vein has been developed in the United States. is there. However, since the injection needle is left pierced in the vein, there is a risk that the needle may come off during the measurement of the blood glucose level and a risk of infection.
Therefore, development of a blood glucose level measuring apparatus that can measure blood glucose level frequently without blood collection and that is free from the risk of infectious diseases is demanded. Furthermore, there is a demand for the development of a blood glucose level measuring device that can be easily and always worn and can be miniaturized.

As a device for non-invasively measuring blood glucose levels using near-infrared continuous light, a device applying a general spectroscopic measurement principle using the principle of molecular absorption has been proposed (for example, a patent) References 1 and 2).
This device corresponds to the fact that when the biological component concentration is quantified using the infrared spectrum of the skin, there is an error in the quantification of the biological component concentration due to the influence of subcutaneous fat. More specifically, It is an apparatus that irradiates the skin with near-infrared continuous light and calculates the glucose concentration from the amount of light absorption.
In this device, a calibration curve indicating the relationship between the glucose concentration, the wavelength of near infrared light to be irradiated and the amount of light absorbed is prepared in advance, and the skin is irradiated with continuous light of near infrared, The return light is scanned in a certain wavelength range using a monochromator, etc., the amount of light absorbed for each wavelength in the wavelength range is obtained, and the amount of light absorbed at each wavelength is compared with a calibration curve, thereby Glucose concentration, that is, blood glucose level is calculated.

Further, skin properties are classified from the absorbance at the specific absorption wavelength of subcutaneous fat selected from the wavelength range of 1700 nm to 1800 nm, and a calibration formula is selected as a substitute characteristic of “skin thickness”.
Further, the “skin thickness” estimated as a preliminary distance between the near-infrared light receiving portion and the light emitting portion is 650 μm is determined to be 1.2 mm or more and less than 1.2 mm, and the light receiving portion and the light emitting portion are determined. The calibration formula is selected after selecting the interval between 650 μm and 300 μm.

On the other hand, for biodiagnosis using near-infrared light, for example, the amount of absorption of near-infrared light in the main component of skin is measured by biological tissue imaging using a time-resolved measurement method, and the main skin is determined based on this absorption amount. Methods are known for determining the proportion of each component, for example, the glucose concentration corresponding to blood sugar.
Since the absorption amount of the skin main component is wavelength-dependent, usually, a plurality of spectra are prepared in advance by varying the variable factors that affect the quantification of the skin main component at a plurality of ratios by multivariate analysis. The method of estimating each ratio of the skin main component by comparing the spectrum of the measurement result of the absorption amount of near infrared light in the skin main component with the above plurality of spectra and selecting a spectrum that matches from these spectra. It is taken.

Japanese Patent No. 3931638 Japanese Patent No. 3994588

However, a conventional device that measures blood glucose level non-invasively using near-infrared continuous light cannot measure only the amount of light absorbed in a path that passes through a specific depth. There is a problem that the glucose concentration corresponding to blood glucose in the skin main component cannot be accurately quantified.
In the device of Patent Document 1, the depth from the skin surface to the subcutaneous fat is defined as “skin thickness”, and the skin properties are classified from the absorbance at the specific absorption wavelength of the subcutaneous fat. To substitute the depth to fat as “skin thickness”, (1) the boundary between the dermis and subcutaneous tissue of the skin is not uniform as the depth from the surface of the skin; There is a sweat gland that secretes fat and stores fat secretions. (3) When categorizing skin properties from the absorbance at the specific absorption wavelength of subcutaneous fat, fat is contained in cells and interstitial fluid of the dermis. Because it is contained, there is a problem because it is difficult to distinguish between dermis and subcutaneous fat.

In general, when the concentration of biological components is quantified using the infrared spectrum of the skin, the depth of the optical path from the skin surface in the skin is roughly estimated by the banana shape characteristic determined by the distance between the light receiving part and the light emitting part. The For example, if the distance between the light receiving part and the light emitting part is 650 μm, the depth of the light path from the skin surface is estimated to be 325 μm, and if the distance between the light receiving part and the light emitting part is 300 μm, the skin surface of the light path Is estimated to be 150 μm.
However, in the apparatus of Patent Document 1, for the above-mentioned reasons, it is not possible to specify a site where the biological component concentration is quantified using the infrared spectrum of the skin, and therefore, one of the interstitial components in the dermis. As a specific part of the reticular layer where glucose is present (Stratum reticulare), it is not possible to selectively measure the absorbance in the optical path that passes through the specific part.

  The present invention has been made in order to solve the above-described problem, and among the observation objects configured by a plurality of layers, backscattered light from an arbitrary layer which is a specific portion to be quantified is transmitted to another layer. It is an object of the present invention to provide a concentration quantification apparatus, a concentration quantification method, and a program capable of non-invasively and accurately quantifying the concentration of a target component in an arbitrary layer by distinguishing from the light from the light.

In order to solve the above problems, the present invention employs the following concentration determination apparatus, concentration determination method, and program.
That is, the concentration quantification device of the present invention is a concentration quantification device for quantifying the concentration of a target component in an arbitrary layer among observation targets composed of a plurality of layers, and irradiates the observation target with short-time pulsed light. An irradiating unit, a light receiving unit that receives light scattered back from the observation target by irradiation of the short-time pulsed light, and each of the plurality of layers of short-time pulsed light irradiated to the observation target An optical path length distribution storage unit that stores a model of an optical path length distribution in the layer; an optical path length acquisition unit that acquires an optical path length of each of the plurality of layers at a predetermined time of the optical path length distribution model; and A time-resolved waveform storage unit that stores a model of a time-resolved waveform of short-time pulsed light that is irradiated to an observation target; and a light intensity model acquisition unit that acquires a light intensity at the predetermined time of the model of the time-resolved waveform A light intensity acquiring unit that acquires the intensity of the light received by the light receiving unit; a light intensity distribution of the light intensity acquired by the light intensity acquiring unit; and the plurality of layers acquired by the optical path length acquiring unit. Based on the optical path length of each layer and the light intensity model acquired by the light intensity model acquisition unit, an integration interval that is a time range of an area corresponding to the light intensity distribution of the arbitrary layer from the light intensity distribution An integration interval calculation unit that calculates a light absorption coefficient calculation unit that calculates a light absorption coefficient of a target component in the arbitrary layer by changing the integration interval calculated by the integration interval calculation unit, and the light absorption coefficient calculation And a concentration calculation unit that calculates the concentration of the target component in the arbitrary layer based on the light absorption coefficient of the target component acquired by the unit.
That is, the concentration quantification device of the present invention is a concentration quantification device for quantifying the concentration of a target component in an arbitrary layer among observation targets composed of a plurality of layers, and irradiates the skin layer to be observed with light. An irradiating unit, a light receiving unit that receives light scattered from the observation target by the light irradiation, an optical path length acquiring unit that acquires an optical path length of the skin layer, and an intensity of light received by the light receiving unit. Based on the light intensity acquisition unit to acquire, the light intensity distribution of the received light intensity acquired by the light intensity acquisition unit, and the optical path length of the skin layer acquired by the optical path length acquisition unit An integration interval calculation unit that calculates an integration interval that is a time range of an area corresponding to the light intensity distribution of the skin layer from the distribution, and calculates the light absorption coefficient of the biological component in the skin layer by changing the integration interval Light absorption coefficient calculator and previous Based on the estimated error rate is stored in advance in the optical absorption coefficient and the skin layer of the biological component, and characterized by being provided with a concentration calculator that calculates the concentration of the target component.

In the concentration quantification device of the present invention, the irradiation unit irradiates the observation target with the short-time pulsed light, and the light receiving unit receives light scattered back from the observation target by the irradiation of the short-time pulsed light. The light intensity acquisition unit acquires the intensity of light received by the light receiving unit, and the integration interval calculation unit acquires the light intensity distribution acquired by the light intensity acquisition unit and the plurality of optical path length distribution storage units acquired A time range of a region corresponding to the light intensity of the arbitrary layer from the light intensity distribution based on the optical path length of each of the layers and the light intensity acquired by the time-resolved waveform storage unit. Calculate the integration interval.
Thus, based on the integration interval calculated by the integration interval calculation unit, it is a specific part to be quantified by obtaining the light intensity in the time zone corresponding to the integration interval from the light intensity received by the light receiving unit. Light from any layer can be measured separately from light from other layers, and the influence of light from other layers on light from any layer can be reduced. Therefore, the light absorption amount of the target component in any layer, that is, the concentration of the target component can be accurately measured. As a result, the concentration of the target component in any layer is quantified noninvasively and with high accuracy. be able to.

  In the concentration quantification device of the present invention, the light absorption coefficient calculation unit calculates a light absorption coefficient of the arbitrary layer based on the integration interval calculated by the integration interval calculation unit, and the light absorption A light absorption coefficient distribution storage unit that calculates and stores a light absorption coefficient distribution in the integration interval based on the light absorption coefficient of the arbitrary layer calculated by the coefficient calculation unit, and a light absorption coefficient acquired by the light absorption coefficient distribution storage unit And a light absorption coefficient acquisition unit that acquires a light absorption coefficient of the target component in the arbitrary layer based on the distribution.

In the concentration determination apparatus of the present invention, the light absorption coefficient calculation unit calculates the light absorption coefficient of an arbitrary layer based on the integration interval calculated by the integration interval calculation unit, and the light absorption coefficient distribution storage unit calculates the light absorption coefficient. The light absorption coefficient distribution in the integration interval is calculated and stored based on the light absorption coefficient of an arbitrary layer calculated by the unit.
Thus, by calculating the light absorption coefficient distribution in the integration section based on the light absorption coefficient of the arbitrary layer calculated based on the integration section, the light absorption coefficient of the target component in the arbitrary layer, that is, the concentration of the target component Can be measured with higher accuracy.

から任意の層の光吸収係数を算出する、ことを特徴とする。 In the concentration determination apparatus of the present invention, the light intensity acquisition unit acquires light intensity at a plurality of times t _{1 to} t _{m that} are equal to or greater than the number n of the observation target layers in the integration interval (where n is A natural number of 1 or more, m is a natural number of n or more), the light absorption coefficient calculating unit is ln (·) indicating a natural logarithm, and I () indicating the light intensity received by the light receiving unit at time t within the integration interval. t), N (t) indicating the light intensity at the time t in the integration interval of the model of the time-resolved waveform of the short-time pulsed light, and the i-th layer at the time t in the integration interval of the model of the optical path length distribution Li (t) indicating the optical path length of, and μ _i indicating the light absorption coefficient of the i-th layer,

The light absorption coefficient of an arbitrary layer is calculated from the above.

In the concentration quantification device of the present invention, the light intensity acquisition unit acquires the light intensity at a plurality of times t _{1 to} t _{m that} are equal to or more than the number n of the observation target layers in the integration interval, and the light absorption coefficient calculation unit The light absorption coefficient of an arbitrary layer is calculated from the above equation (1).
In this way, by measuring the time-resolved backscattered light, backscattered light from layers other than any layer can be reduced as noise, and the influence of the layer other than any layer on the concentration of the target component can be reduced. Can be reduced. Therefore, the concentration of the target component can be measured with higher accuracy.

  The concentration determination apparatus of the present invention is characterized in that the plurality of times when the light intensity acquisition unit acquires the light intensity includes a peak time of the optical path length distribution of each of the plurality of layers.

  In the concentration quantification device of the present invention, the plurality of times at which the light intensity acquisition unit acquires the light intensity includes the peak time of the optical path length distribution of each layer of the plurality of layers, so that the plurality of layers being observed Any layer can be selected efficiently. Therefore, the concentration of the target component in any layer can be measured with higher accuracy.

から任意の層の光吸収係数を算出する、ことを特徴とする。 In the concentration quantification device according to the present invention, the light intensity acquisition unit acquires light intensity from a predetermined time in the integration interval to at least a predetermined time τ, and the light absorption coefficient calculation unit indicates a natural logarithm. ln (·), I (t) indicating the light intensity received by the light receiving unit at time t within the integration interval, and light intensity at time t within the integration interval of the time-resolved waveform model of the short-time pulsed light N (t) indicating the optical path length of the i-th layer at time t within the integration interval of the model of the optical path length distribution, n (t) indicating the number of layers to be observed, n, Using μi indicating the light absorption coefficient,

The light absorption coefficient of an arbitrary layer is calculated from the above.

In the concentration determination apparatus of the present invention, the light intensity acquisition unit acquires the light intensity between a predetermined time in the integration interval and at least the predetermined time τ, and the light absorption coefficient calculation unit calculates the light absorption coefficient of an arbitrary layer. Is calculated from the above equation (2).
In this way, by measuring the time-resolved backscattered light, backscattered light from layers other than any layer can be reduced as noise, and the influence of the layer other than any layer on the concentration of the target component can be reduced. Can be reduced. Therefore, the concentration of the target component can be measured with higher accuracy.

から前記任意の層における前記目的成分の濃度を算出する、ことを特徴とする。 In the concentration determination apparatus of the present invention, the irradiation unit irradiates light having a plurality of wavelengths 1 to q, and the light absorption coefficient calculation unit includes a plurality of light irradiation coefficients irradiated by the irradiation unit in the arbitrary layer. Calculated for each wavelength, the concentration calculation unit is μa (i) indicating the light absorption coefficient of the wavelength i in the a-th layer which is the arbitrary layer, and gj indicating the molar concentration of the j-th component forming the observation target. , Εj (i) indicating the light absorption coefficient for the wavelength i of the jth component, p indicating the number of main components forming the observation object, and q indicating the number of types of wavelengths irradiated by the irradiation unit,

From the above, the concentration of the target component in the arbitrary layer is calculated.

In the concentration determination apparatus of the present invention, the irradiation unit irradiates light having a plurality of wavelengths 1 to q, and the light absorption coefficient calculation unit calculates the light absorption coefficient in an arbitrary layer for each of the plurality of wavelengths irradiated by the irradiation unit. Then, the concentration calculation unit calculates the concentration of the target component in an arbitrary layer from the above equation (3).
In this way, by measuring the time-resolved backscattered light, backscattered light from layers other than any layer can be reduced as noise, and the influence of the layer other than any layer on the concentration of the target component can be reduced. Can be reduced. Therefore, the concentration of the target component can be measured with higher accuracy.

  In the concentration quantification device according to the present invention, the plurality of lights irradiated by the irradiation unit includes light having a wavelength that increases a light absorption coefficient of the target component.

  The concentration quantification apparatus of the present invention is characterized in that the plurality of lights emitted by the irradiating unit includes light having a wavelength at which the orthogonality of the absorption spectrum distribution of each component of the main component constituting the observation target is increased. To do.

The concentration quantification method of the present invention includes an irradiation unit that irradiates light to the skin layer, and a light receiving unit that receives light scattered from the skin layer by the light irradiation, and the concentration of biological components in the skin layer is determined. A concentration quantification method using a concentration quantification device for quantifying, wherein the irradiation unit irradiates the skin layer with the light, and the light receiving unit receives light scattered from the skin layer by the light irradiation. The light intensity acquiring unit acquires the intensity of light received by the light receiving unit at a predetermined time after the time when the irradiating unit irradiated the light, and the optical path length of the skin layer is acquired by the optical path length acquiring unit. Based on the light intensity distribution of the intensity of the received light acquired by the light intensity acquisition unit and the optical path length of the skin layer acquired by the optical path length acquisition unit by the integration interval calculation unit , When the area corresponds to the light intensity distribution of the skin layer Calculating the integral interval in the range of, by the light absorption coefficient calculating unit, said integration interval is changed to calculate the optical absorption coefficient of a biological component in the skin layer, the concentration calculator, the optical absorption coefficient of the biological component And the concentration of the biological component is calculated based on the pre-stored estimated error rate of the skin layer.
The concentration quantification method of the present invention includes an irradiation unit that irradiates an observation target composed of a plurality of layers with a short-time pulsed light, and a light receiving unit that receives light scattered back from the observation target by the irradiation of the short-time pulsed light. An optical path length distribution storage unit for storing a model of an optical path length distribution in each of the plurality of layers of short-time pulse light irradiated to the observation target, and a short irradiation to the observation target A time-resolved waveform storage unit that stores a time-resolved waveform model of time-pulsed light, and a concentration quantification method using a concentration quantification device that quantifies the concentration of a target component in any layer of the observation target, The irradiation unit irradiates the observation target with a short-time pulse light, the light receiving unit receives light scattered back from the observation target by the irradiation of the short-time pulse light, and the light intensity acquisition unit The irradiation unit acquires the intensity of light received by the light receiving unit at a predetermined time after the time when the pulsed light is irradiated for a short time, and the optical path length distribution unit acquires the optical path length distribution from the optical path length distribution storage unit. The optical path length of each of the plurality of layers at the predetermined time of the model is acquired, and the model of the time-resolved waveform model of the short-time pulse light is acquired from the time-resolved waveform storage unit by the light intensity model acquisition unit. The light intensity at the predetermined time is acquired, and the light intensity distribution acquired by the light intensity acquisition unit and the optical path of each of the plurality of layers acquired by the optical path length distribution acquisition unit by an integration interval calculation unit Based on the length and the light intensity acquired by the time-resolved waveform acquisition unit, an integration interval that is a time range of a region corresponding to the light intensity distribution of the arbitrary layer is calculated from the light intensity distribution, By the absorption coefficient calculator The integration interval calculated by the integration interval calculation unit is changed to calculate the light absorption coefficient of the target component in the arbitrary layer, and based on the light absorption coefficient calculated by the light absorption coefficient calculation unit by the concentration calculation unit, The concentration of the target component in the arbitrary layer is calculated.

  In the concentration determination method of the present invention, the irradiation unit irradiates the observation target with short-time pulse light, the light receiving unit receives light scattered back from the observation target due to the short-time pulse light irradiation, and the light intensity acquisition unit The light intensity distribution acquired by the light intensity acquisition unit by the integration interval calculation unit by acquiring the intensity of light received by the light receiving unit at a predetermined time after the time when the irradiation unit irradiated the short-time pulsed light And the arbitrary layer from the light intensity distribution based on the optical path length of each of the plurality of layers acquired by the optical path length distribution acquisition unit and the light intensity acquired by the time-resolved waveform acquisition unit. An integration interval of a region corresponding to the light intensity of is calculated.

  In this way, the integration interval calculation unit calculates the integration interval of the region corresponding to the light intensity of an arbitrary layer from the light intensity distribution, and based on the integration interval calculated by the integration interval calculation unit, the light receiving unit Can obtain the light intensity in the time zone corresponding to the integration interval from the received light intensity, can measure the light from any layer separately from the light from other layers, from any layer It is possible to reduce the influence of light from other layers on the light. Therefore, the light absorption amount of the target component in any layer, that is, the concentration of the target component can be accurately measured. As a result, the concentration of the target component in any layer can be accurately and efficiently noninvasively. It can be quantified.

The program of the present invention includes an irradiation unit that irradiates light to the skin layer, and a light receiving unit that receives light scattered from the skin layer by irradiation of the light, and quantifies the concentration of biological components in the skin layer An irradiation procedure for irradiating the skin layer with the light, a light receiving procedure for receiving light scattered from the skin layer due to the light irradiation, and a predetermined time after the light irradiation time to the computer of the concentration determination device A light intensity acquisition procedure for acquiring the intensity of the received light, an optical path length acquisition procedure for acquiring the optical path length of the skin layer, a light intensity distribution of the intensity of the received light acquired by the light intensity acquisition procedure , and An integration interval calculation procedure for calculating an integration interval that is a time range of an area corresponding to the light intensity distribution of the skin layer based on the optical path length of the skin layer acquired by the optical path length acquisition unit , the integration interval calculation procedure By Light absorption coefficient calculating step of calculating the light absorption coefficient of the calculated integral interval by changing the biological component in the skin layer and on the estimated error rate the light absorption coefficient of the biological component is previously stored in said skin layer Based on this, a concentration calculation procedure for calculating the concentration of the biological component is executed.
The program of the present invention includes an irradiation unit that irradiates an observation target composed of a plurality of layers with a short-time pulsed light, and a light-receiving unit that receives light backscattered from the observation target due to the irradiation of the short-time pulsed light. An optical path length distribution storage unit for storing a model of an optical path length distribution in each of the plurality of layers of the short-time pulse light applied to the observation target; and a short-time pulse applied to the observation target A time-resolved waveform storage unit that stores a model of a time-resolved waveform of light, and a computer for a concentration quantification device that quantifies the concentration of a target component in an arbitrary layer of the observation target; An irradiation procedure for irradiating light, a light receiving procedure for receiving light scattered back from the observation object by irradiation of the short-time pulsed light, a predetermined time after the time of irradiating the short-time pulsed light A light intensity acquisition procedure for acquiring the intensity of light received at intervals, and acquiring an optical path length of each of the plurality of layers at the predetermined time of the optical path length distribution model from the optical path length distribution storage unit Obtained from the optical path length acquisition procedure, the time-resolved waveform storage unit, the light intensity model acquisition procedure for acquiring the light intensity at the predetermined time of the model of the time-resolved waveform of the short-time pulsed light, and the light intensity acquisition procedure Based on the light intensity distribution, the optical path length of each of the plurality of layers acquired by the optical path length acquisition procedure, and the light intensity acquired by the light intensity model acquisition procedure, the light intensity distribution To an integration interval calculation procedure for calculating an integration interval which is a time range of an area corresponding to the light intensity distribution of the arbitrary layer, and the integration interval calculated by the integration interval calculation procedure is changed to change the arbitrary interval Light absorption coefficient calculation procedure for calculating the light absorption coefficient of the target component in the layer, concentration calculation procedure for calculating the concentration of the target component in the arbitrary layer based on the light absorption coefficient calculated by the light absorption coefficient calculation procedure , Is executed.

  In the program of the present invention, an irradiation procedure for irradiating the observation target with a short-time pulse light on the computer of the concentration quantification apparatus, a light-receiving procedure for receiving light scattered back from the observation target by the irradiation of the short-time pulse light, and a short-time pulse After executing the light intensity acquisition procedure for acquiring the intensity of light received at a predetermined time after the light irradiation time, the light intensity distribution acquired by the light intensity acquisition unit and the optical path length distribution storage unit Based on the optical path length of each of the acquired multiple layers and the light intensity acquired by the time-resolved waveform storage unit, the integration interval of the region corresponding to the light intensity of any layer is calculated from the light intensity distribution Calculated by the integration interval calculation procedure, the light absorption coefficient calculation procedure for calculating the light absorption coefficient of the target component in an arbitrary layer based on the integration interval calculated by the integration interval calculation procedure, and the light absorption coefficient calculation procedure. Was based on the optical absorption coefficient, density calculation step of calculating the concentration of the target component in any layer, is allowed to sequentially execute.

  Thus, based on the light intensity acquired by the light intensity acquisition procedure, the optical path length of each of the plurality of layers acquired by the optical path length acquisition procedure, and the light intensity acquired by the light intensity model acquisition procedure Then, by executing the integration interval calculation procedure for calculating the integration interval of the region corresponding to the light intensity of an arbitrary layer from the light intensity distribution, the light receiving unit is based on the integration interval calculated by the integration interval calculation unit. Only the intensity of light in the time zone corresponding to the integration interval can be acquired from the intensity of received light, and the influence of light from other layers on the light from any layer can be reduced. Therefore, the light absorption amount of the target component in any layer, that is, the concentration of the target component can be accurately measured. As a result, the concentration of the target component in any layer can be accurately and efficiently noninvasively. It can be quantified.

It is a schematic block diagram which shows the structure of the blood glucose level measuring apparatus of the 1st Embodiment of this invention. It is a schematic diagram which shows the cross section of a human skin tissue. It is a figure which shows the optical path length distribution of each layer which the simulation part computed. It is a figure which shows the time-resolved waveform which the simulation part computed. It is a figure which shows the absorption spectrum of the main component of skin. It is a flowchart which shows the operation | movement which the blood glucose level measuring apparatus of the 1st Embodiment of this invention measures a blood glucose level. It is a flowchart which shows the operation | movement which the blood glucose level measuring apparatus of the 2nd Embodiment of this invention measures a blood glucose level. It is a schematic block diagram which shows the structure of the blood glucose level measuring apparatus of the 3rd Embodiment of this invention. It is a schematic block diagram which shows the structure of the blood glucose level measuring apparatus of the 4th Embodiment of this invention. It is a figure which shows the time-resolved waveform of the light intensity N (t) at the time of non-absorption obtained in the simulation part. It is the figure which showed the time-resolved waveform of light intensity I (t) at the time of absorption obtained in the simulation part with the linear scale. It is the figure which showed the time-resolved waveform of the light intensity I (t) at the time of absorption obtained in the simulation part on the log scale. It is a flowchart which shows the operation | movement which the blood glucose level measuring apparatus of the 4th Embodiment of this invention measures a blood glucose level. It is a flowchart which shows the operation | movement which the blood glucose level measuring apparatus of the 4th Embodiment of this invention measures a blood glucose level. It is a figure which shows the relationship between the light absorption coefficient in a dermis layer, and an integration area. It is a flowchart which shows the operation | movement which the blood glucose level measuring apparatus of the 5th Embodiment of this invention measures a blood glucose level. It is a flowchart which shows the operation | movement which the blood glucose level measuring apparatus of the 5th Embodiment of this invention measures a blood glucose level. It is a schematic block diagram which shows the structure of the blood glucose level measuring apparatus of the 6th Embodiment of this invention. It is a schematic block diagram which shows the structure of the blood glucose level measuring apparatus of the 7th Embodiment of this invention.

An embodiment for carrying out a concentration determination apparatus, a concentration determination method, and a program according to the present invention will be described.
In the present invention, a blood glucose level measuring device will be described as an example of a concentration determination device, the skin of a human palm as an observation target, and glucose as a target component.

[First Embodiment]
FIG. 1 is a schematic block diagram showing a configuration of a blood sugar level measuring apparatus according to the first embodiment of the present invention.
The blood glucose level measuring apparatus 100 includes a simulation unit 101, an optical path length distribution storage unit 102, a time-resolved waveform storage unit 103, an irradiation unit 104, a light receiving unit 105, a measured light intensity acquisition unit 106, an optical path length acquisition unit 107, and a non-absorbing light. An intensity acquisition unit (light intensity model acquisition unit) 108, a light absorption coefficient calculation unit 109, and a concentration calculation unit 110 are provided.
The blood glucose level measuring apparatus 100 measures the concentration of glucose (target component) contained in the dermis layer (arbitrary layer) of the skin (observation target).

The simulation part 101 performs the simulation which irradiates light with respect to the skin model whose light absorption coefficient is zero.
The optical path length distribution storage unit 102 stores an optical path length distribution of a skin model having a light absorption coefficient of zero.
The time-resolved waveform storage unit 103 stores a time-resolved waveform of a skin model having a light absorption coefficient of zero.
The irradiation unit 104 irradiates the skin with short-time pulsed light. The plurality of short-time pulse lights emitted by the irradiating unit 104 is light having a wavelength that increases the orthogonality of the absorption spectrum distribution of each component of the main components constituting the skin, that is, each of the main components constituting the skin. Among the components, the maximum value of the absorption spectrum of a specific component in a certain main component includes light having a wavelength that is significantly different from the maximum value of the absorption spectrum of another component.

The light receiving unit 105 receives light obtained by back-scattering the short-time pulse light by the skin.
Here, the short-time pulsed light is pulsed light whose pulse width is shorter than the time required for light to propagate directly from the irradiation unit 104 to the light receiving unit 105 in the air. 0.1 ps to 10 ps refers to pulsed light having a time interval of 1 ps to 100 ps between two pulsed lights.
The optical path length distribution is a distribution function representing the length (optical path length) of the movement path of light (photons) based on the time until the light (photons) reaches the light receiving unit 105.

The measurement light intensity acquisition unit 106 acquires the light intensity at a certain time of the light received by the light receiving unit 105.
The optical path length acquisition unit 107 acquires the optical path length at a certain time from the optical path length distribution storage unit 102.
The non-absorption light intensity acquisition unit 108 acquires a light intensity model when the light absorption coefficient at a certain time is set to zero (zero) from the time-resolved waveform storage unit 103.
The light absorption coefficient calculation unit 109 calculates a light absorption coefficient in the dermis layer of the skin irradiated with the short-time pulse light.
The concentration calculation unit 110 calculates the concentration of glucose contained in the dermis layer.

In the blood glucose level measuring apparatus 100, the irradiating unit 104 irradiates the skin with short-time pulsed light, and the light-receiving unit 105 receives light back-scattered by the skin with the short-time pulsed light.
Here, the structure of the human skin tissue to be observed will be described.
FIG. 2 is a schematic diagram showing a cross section of a human skin tissue. The skin 31 is composed of three layers of an epidermis layer 32, a dermis layer (arbitrary layer) 33, and a subcutaneous tissue 34.
The epidermis layer 32 is an outermost thin layer having a thickness of 0.2 mm to 0.3 mm, and is a layer containing about 60% of water, protein, lipid and glucose, and includes a stratum corneum, a granular layer, and a spiny layer. , Including bottom layer.
The dermis layer 33 is a layer formed under the epidermis layer 32 and having a thickness of 0.5 mm to 2 mm. The dermis layer 33 is a layer containing approximately 60% of water, protein, lipid, and glucose. , Hair roots, sebaceous glands, sweat glands, hair follicles, blood vessels, lymphatic vessels, and the like.
The subcutaneous tissue 34 is a layer having a thickness of 1 to 3 mm formed under the dermis layer 33. The subcutaneous tissue 34 is mostly made of subcutaneous fat containing approximately 90% or more of lipids and the balance being water.

  Capillaries and the like are developed in the dermis layer 33, mass transfer according to blood glucose occurs rapidly, and the glucose concentration in the dermis layer 33 follows the blood glucose concentration (blood glucose level). It is thought to change. Therefore, in the blood glucose level measuring apparatus 100, the irradiation unit 104 and the light receiving unit 105 are brought into close contact with the surface of the skin 31 with a predetermined inter-irradiation distance W, and light is emitted from the irradiation unit 104 to the surface of the skin 31 in this close contact state. The light is reflected by the tissue in the skin 31, and the light that is scattered toward the irradiation unit 104 and the light receiving unit 105 (back scattered light) is detected by the light receiving unit 105.

  Next, the measurement light intensity acquisition unit 106 acquires the intensity of light received by the light receiving unit 105 at time t. Next, the optical path length acquisition unit 107 acquires the optical path length of each layer of the skin at time t of the optical path length distribution in the skin model from the optical path length distribution storage unit 102, and the non-absorbing light intensity acquisition unit 108 calculates the time-resolved waveform. The intensity of light at time t of the time-resolved waveform of the short-time pulsed light in the skin model is acquired from the storage unit 103.

  Next, the light absorption coefficient calculation unit 109 obtains the light intensity acquired by the measurement light intensity acquisition unit 106, the optical path length of each layer of the skin acquired by the optical path length acquisition unit 107, and the light intensity acquired by the non-absorption light intensity acquisition unit 108. Based on the above, the light absorption coefficient of the dermis layer of the skin is calculated, and the concentration calculation unit 110 calculates the concentration of glucose in the dermis layer based on the light absorption coefficient calculated by the light absorption coefficient calculation unit 109.

  In this blood glucose level measuring apparatus 100, since the glucose concentration is calculated using the light absorption coefficient of the dermis layer 33, which is a layer having a specific depth of the skin 31, the influence of noise caused by layers other than the dermis layer 33 can be reduced. It is possible to calculate the concentration of glucose contained in the dermis layer 33 which is a layer having a specific depth. Therefore, the light absorption amount of glucose contained in the layer having a specific depth, that is, the glucose concentration can be measured noninvasively with high accuracy.

Next, the operation of the blood sugar level measuring apparatus 100 will be described.
The blood glucose level measuring apparatus 100 needs to calculate the optical path length distribution and the time-resolved waveform in each layer of the skin model before measuring the blood glucose level.
First, a method for calculating the optical path length distribution and time-resolved waveform of the skin model will be described.
First, the simulation unit 101 generates a skin model. The skin model is generated by determining the light scattering coefficient, light absorption coefficient, and thickness of each layer of the skin. Here, if the skin portion is specified, the scattering coefficient and thickness of each layer in the specified skin portion are small depending on the individual, so it may be determined by taking a sample in advance. The thickness of the epidermis layer 32 is approximately 0.3 mm, the thickness of the dermis layer 33 is approximately 1.2 mm, and the thickness of the subcutaneous tissue 34 is approximately 3.0 mm.
The light absorption coefficient of the skin model used here is zero. The reason is that the amount of light absorption is calculated using this skin model.

When the simulation unit 101 generates a skin model, the simulation unit 101 performs a simulation of irradiating the skin model with light. At this time, it is necessary to determine the distance W between the position of the irradiation unit 104 and the position of the light receiving unit 105. The simulation is performed using, for example, a Monte Carlo method.
The simulation by the Monte Carlo method is performed as follows, for example.

  First, the simulation unit 101 uses a model of light to be irradiated as a photon (light beam), and performs calculation to irradiate the skin model with the photon. Photons irradiated to the skin model move in the skin model. At this time, the photon determines the distance L and the direction θ to the next advancing point by the random number R. The simulation unit 101 calculates the distance L to the point where the photon advances next by Expression (4).

Here, ln (A) represents the natural logarithm of A, and μs represents the scattering coefficient of the s-th layer (any one of the epidermis layer, dermis layer, and subcutaneous tissue layer) of the skin model.
In addition, the simulation unit 101 calculates the direction θ up to the point where the photon advances next by Expression (5).

However, g shows the anisotropic parameter which is the average of cosine (cos) of a scattering angle, and the anisotropic parameter of skin is about 0.9.
The simulation unit 101 can calculate the movement path of photons from the irradiation unit 104 to the light receiving unit 105 by repeating the calculations of the above formulas (4) and (5) every unit time. The simulation unit 101 calculates a movement distance for a plurality of photons. For example, the simulation unit 101 calculates the movement distance for 10 ⁸ photons.

FIG. 3 is a diagram illustrating the optical path length distribution of each layer calculated by the simulation unit 101.
In FIG. 3, the horizontal axis is the elapsed time from photon irradiation, and the vertical axis is a logarithmic display of the optical path length.
The simulation unit 101 classifies each movement path of photons that reach the light receiving unit 105 for each layer through which the movement path passes. And the simulation part 101 calculates the optical path length distribution of each layer of a skin as shown in FIG. 3 by calculating the average length of the movement path | route of the photon which arrived for every unit time for every classified layer.

Moreover, the simulation part 101 calculates the time-resolved waveform of a skin model as shown in FIG. 4 by calculating the number of photons reaching the light receiving part 104 every unit time.
FIG. 4 is a diagram illustrating a time-resolved waveform calculated by the simulation unit 101. In FIG. 4, the horizontal axis represents the elapsed time from photon irradiation, and the vertical axis represents the number of photons detected by the light receiving unit 8.
Through the processing as described above, the simulation unit 101 calculates the optical path length distribution and time-resolved waveform of the skin model for a plurality of wavelengths. At this time, the simulation unit 101 uses light having a wavelength that increases the orthogonality of the absorption spectrum of the skin main components (water, protein, lipid, glucose, etc.), that is, the skin main components (water, protein, lipid, glucose, etc.). Among each component, it is preferable to calculate the optical path length distribution and the time-resolved waveform for light having a wavelength at which the maximum value of the absorption spectrum of a specific component in a certain main component is significantly different from the maximum value of the absorption spectrum of another component.

FIG. 5 is a graph showing the absorption spectrum of the main component of the skin. In FIG. 5, the horizontal axis represents the wavelength of light to be irradiated, and the vertical axis represents the absorption coefficient.
According to FIG. 5, it can be seen that the absorption coefficient of glucose is maximized when the wavelength is 1600 nm, and the absorption coefficient of water is maximized when the wavelength is 1450 nm.
Therefore, for example, the simulation unit 101 uses light having a wavelength that increases the orthogonality of the absorption spectrum distribution of each component of the main component constituting the skin, such as 1450 nm and 1600 nm, that is, each of the main component constituting the skin. Among the components, it is preferable to calculate the optical path length distribution and the time-resolved waveform for light having a wavelength at which the maximum value of the absorption spectrum of a specific component in a main component is significantly different from the maximum value of the absorption spectrum of another component.

  When the simulation unit 101 calculates the optical path length distribution and time-resolved waveform of the skin model for a plurality of wavelengths, the optical path length distribution storage unit 102 stores information on the calculated optical path length distribution, and the time-resolved waveform storage unit 103 Information on the calculated time-resolved waveform is stored. The simulation unit 101 may be configured not to be included in the blood glucose measurement device 100. In this case, the blood glucose measurement device 100 measures the blood glucose level by storing the result of the simulation performed by the external device in the optical path length distribution storage unit 102 and the time-resolved waveform storage unit 103.

Next, the operation in which the blood sugar level measuring apparatus 100 measures the blood sugar level will be described with reference to FIG.
First, when a user (a person to be measured) places the blood sugar level measuring device 100 on the skin such as a wrist and operates the blood sugar level measuring device 100 by pressing a measurement start switch (not shown) or the like, the irradiation unit 104 31 is irradiated with short-time pulsed light having a wavelength λ ₁ (step S1).

Here, the wavelength λ ₁ is _one of a plurality of wavelengths for which the simulation unit 101 has calculated the optical path length distribution and the time-resolved waveform.
For example, among the main components constituting the skin, light having a wavelength at which the light absorption coefficient of a specific component in one main component is larger than the light absorption coefficient of another component, that is, the minimum value of the light absorption coefficient of a specific component is It is preferable to calculate the optical path length distribution and the time-resolved waveform for light having a wavelength significantly different from the minimum value of the light absorption coefficient of the component.

When the irradiation unit 104 emits the short-time pulse light, the light receiving unit 105 receives the light emitted from the irradiation unit 104 and backscattered by the skin 31 (step S2).
At this time, the light receiving unit 105 records the received light intensity for each unit time (for example, every 1 picosecond) from the start of irradiation in an internal memory (not shown).

Next, when the light receiving unit 105 completes the light reception, the measurement light intensity acquisition unit 106 acquires the same amount of received light intensity I (t) at different time t stored in the internal memory as the number of skin layers ( Step S3).
In the flowchart of FIG. 6, a case where concentration measurement is performed using three types of wavelengths for three layers of skin will be described.
That is, when the measurement light intensity acquisition unit 106 performs concentration measurement using four types of wavelengths for the three layers of the skin, the received light intensity I (t ₁ ) to I at _three different times t _{1 to} t ₃ . (T ₃ ) is acquired. Here, the reason why the received light intensity is obtained in the same number as the number of skin layers is to calculate the absorption coefficient of each skin layer by simultaneous equations in the processing described later.

In addition, the times t ₁ to t _{3 at} which the measurement light intensity acquisition unit acquires the light intensity may be times when the optical path length distribution of each layer of the skin becomes a peak. In other words, the light intensity at the time obtained by adding the time when the optical path length of each layer of the skin is maximized in the graph shown in FIG.

When the measurement light intensity acquisition unit 106 acquires the received light intensities I (t ₁ ) to I (t ₃ ), the optical path length acquisition unit 107 calculates the time from the optical path length distribution of the wavelength λ ₁ stored in the optical path length distribution storage unit 102. t ₁ ~t optical path length of each layer of the skin at _{3 L 1 (t 1) ~L} 1 (t 3), L 2 (t 1) ~L 2 (t 3), L 3 (t 1) ~L 3 ( t ₃₎ to get (step S4).
When the measurement light intensity acquisition unit 106 acquires the received light intensities I (t ₁ ) to I (t ₃ ), the non-absorption light intensity acquisition unit 108 performs time resolution of the wavelength λ ₁ stored in the time-resolved waveform storage unit 103. from the waveform, the time _t 1 detected in ~t ₃ photon number _{N (t 1) ~N (t} 3) to get (step S5).

When the optical path length acquisition unit 107 acquires the optical path length of each layer of the skin and the non-absorption light intensity acquisition unit 108 acquires the number of detected photons, the light absorption coefficient calculation unit 109 calculates each layer of the skin based on Equation (6). to the calculated light absorption coefficient _μ 1 _{~μ 3} (step S6). Here, the light absorption coefficient μ ₁ indicates the light absorption coefficient of the epidermis layer, the light absorption coefficient μ ₂ indicates the light absorption coefficient of the dermis layer, and the light absorption coefficient μ ₃ indicates the light absorption coefficient of the subcutaneous tissue. .

However, ln (A) shows the natural logarithm of A, N (t) shows the light intensity at time t of the model of the time-resolved waveform of the short pulse light having a specific wavelength lambda _k. I _in indicates the light intensity of the short-time pulse light irradiated by the irradiation unit 7. N _in indicates the number of photons on which the simulation unit 2 has simulated irradiation.

When the light absorption coefficient calculation unit 109 calculates the light absorption coefficients μ _{1 to} μ ₃ of each layer of the skin, the light absorption coefficient calculation unit 109 calculates the light absorption coefficient μ with respect to the same number of wavelengths as the number of types of skin main components. It determines whether to calculate the _{1 ~μ 3} (step S7).
In this embodiment, since the blood sugar level is measured with four main components of skin, water, protein, lipid, and glucose, the light absorption coefficient calculation unit 109 performs light for four wavelengths λ _{1 to} λ ₄ . It is determined whether or not the absorption coefficients μ _{1 to} μ ₃ are calculated. Here, the wavelengths λ _{1 to} λ ₄ are selected from a plurality of wavelengths calculated by the simulation unit 101 for the optical path length distribution and the time-resolved waveform.

When the light absorption coefficient calculation unit 109 determines that there are wavelengths λ _{1 to} λ ₄ for which the light absorption coefficients μ _{1 to} μ ₃ are not calculated (step S7: NO), the process returns to step S1 and still has the light absorption coefficient μ. and calculates the light absorption coefficient _μ 1 _{~μ 3} wavelengths lambda ₁ to [lambda] _4, which is not calculated _{1 ~μ 3.}
On the other hand, when the light absorption coefficient calculation unit 109 determines that the light absorption coefficients μ _{1 to} μ ₃ of the wavelengths λ _{1 to} λ ₄ are calculated (step S7: YES), the concentration calculation unit 110 calculates the equation (7 ) To calculate the concentration of glucose contained in the dermis layer (step S8).

_{However, μ 2 (1) ~μ 2} (4) shows the optical absorption coefficient of the wavelength lambda ₁ to [lambda] ₄ in the dermis layer. Further, g ₁ to g ₄ shows the water respectively in the dermal layer is the main component of skin, proteins, lipids, the molar concentration of glucose. _{Further, ε 1 (1) ~ε 1} (4) shows a molar extinction coefficient of water with respect to the wavelength _{λ 1 ~λ 4, ε 2 (} 1) ~ε 2 (4) is for the wavelength lambda ₁ to [lambda] ₄ Indicates the molar extinction coefficient of the protein, ε _{3 (1) to} ε _{3 ( 4)} indicate the molar extinction coefficient of the lipid for wavelengths λ _{1 to} λ ₄ , and ε _{4 (1) to} ε _{4 (4)} indicate the wavelength The molar extinction coefficient of glucose with respect to λ _{1 to} λ ₄ is shown.
In other words, by calculating the g ₄ of the formula (7) can be obtained the molar concentration of glucose contained in the dermal layer.

Here, the reason why the molar concentration of glucose can be obtained by the equation (7) will be described.
Since the wavelength dependence of the skin scattering coefficient is small, changes in the number of detected photons N (t) and the optical path length Ln (t) with respect to the wavelength can be ignored. Further, it can be expressed as Absorbance = Molar extinction coefficient × Molar concentration according to the Beer-Lambert law. Thus, by eliminating the detected photon number N (t) from time-resolved measurement obtained at two wavelengths, the relational expression between the absorption coefficient difference obtained in the dermis layer and the molar absorption coefficient of each component forming the skin Equation (7) showing can be derived.

  According to this embodiment, short-time pulse light is irradiated, and the glucose concentration is quantified based on the intensity of light received at a predetermined time. Thus, the absorption coefficient of the dermis layer can be selectively calculated from the light received at a predetermined time. Thereby, the glucose concentration of a specific skin layer can be calculated, the influence of noise by other layers can be reduced, and a highly accurate blood sugar level can be calculated.

[Second Embodiment]
The second embodiment of the present invention will be described in detail.
The configuration of the blood glucose level measuring device in the second embodiment is the same as that of the blood glucose level measuring device 100 in the first embodiment, and the measurement light intensity acquisition unit 106, the optical path length acquisition unit 107, and the non-absorption light intensity acquisition. The operations of the unit 108 and the light absorption coefficient calculation unit 109 are different.

FIG. 7 is a flowchart showing the operation of the blood sugar level measuring apparatus for measuring the blood sugar level.
First, when the blood sugar level measuring apparatus 100 is operated, the irradiating unit 104 irradiates the skin with short-time pulsed light having a wavelength λ ₁ (step S11). Here, the wavelength λ ₁ is _one of a plurality of wavelengths for which the simulation unit 101 has calculated the optical path length distribution and the time-resolved waveform.

When the irradiation unit 104 emits the short-time pulse light, the light receiving unit 105 receives the light emitted from the irradiation unit 104 and backscattered by the skin (step S12). At this time, the light receiving unit 105 registers the received light intensity for each unit time (for example, every 1 picosecond) from the start of irradiation in the internal memory.
When the light receiving unit 105 completes the light reception, the measurement light intensity acquisition unit 106 acquires the time distribution of the received light intensity from a certain time to the time τ from the received light intensity stored in the internal memory (step S13).

When the measurement light intensity acquisition unit 106 acquires the time distribution of the received light intensity during the time τ, the optical path length acquisition unit 107 starts from the optical path length distribution of the wavelength λ ₁ stored in the optical path length distribution storage unit 102 from a certain time. Obtain the optical path length of each layer of skin during time τ.
In the flowchart of FIG. 7, a case where concentration measurement is performed on three layers of skin using four types of wavelengths will be described.
That is, when the measurement light intensity acquisition unit 106 performs concentration measurement using three types of wavelengths for the three layers of the skin, the optical path lengths L _{1 to} L ₃ of each layer of the skin between a certain time and the time τ. Is acquired (step S14).

When the measurement light intensity acquisition unit 106 acquires the time distribution of the received light intensity during the time τ, the non-absorption light intensity acquisition unit 108 uses the time-resolved waveform of the wavelength λ ₁ stored in the time-resolved waveform storage unit 103. The number of detected photons from a certain time to time τ is acquired (step S15).

When the optical path length acquisition unit 107 acquires the optical path length of each layer of skin and the non-absorption light intensity acquisition unit 108 acquires the number of detected photons, the light absorption coefficient calculation unit 109 calculates each layer of the skin based on Expression (8). to the calculated light absorption coefficient _μ 1 _{~μ 3} (step S16). Here, the light absorption coefficient μ ₁ indicates the light absorption coefficient of the epidermis layer, the light absorption coefficient μ ₂ indicates the light absorption coefficient of the dermis layer, and the light absorption coefficient μ ₃ indicates the light absorption coefficient of the subcutaneous tissue. .

Here, ln (A) represents the natural logarithm of A. Further, I (t) indicates the light reception intensity of the light receiving unit 105 at time t, and I _in indicates the light intensity of the short-time pulsed light irradiated by the irradiation unit 104. N (t) represents the number of detected photons at time t of the time-resolved waveform, and N _in represents the number of photons on which the simulation unit 101 has simulated the irradiation. L ₁ (t) to L ₃ (t) indicate the optical path length of each layer of the skin at time t.

When the light absorption coefficient calculation unit 109 calculates the light absorption coefficients μ _{1 to} μ ₃ of each layer of the skin, the light absorption coefficient calculation unit 109 calculates the light absorption coefficient μ with respect to the same number of wavelengths as the number of types of skin main components. It determines whether to calculate the _{1 ~μ 3} (step S17). In this embodiment, blood sugar levels are measured with four main components of skin, water, protein, lipid, and glucose, so that the light absorption coefficient calculation unit 109 performs light for _four wavelengths λ _{1 to} λ ₄ . It is determined whether or not the absorption coefficients μ _{1 to} μ ₃ are calculated. Here, the wavelengths λ _{1 to} λ ₄ are selected from a plurality of wavelengths calculated by the simulation unit 101 for the optical path length distribution and the time-resolved waveform.

If the light absorption coefficient calculation unit 109 determines that there are wavelengths λ _{1 to} λ ₄ for which the light absorption coefficients μ _{1 to} μ ₃ are not calculated (step S17: NO), the process returns to step S1 and still absorbs light. and calculates the light absorption coefficient _μ 1 _{~μ 3} wavelengths lambda ₁ to [lambda] _4, which is not calculated coefficient _μ 1 _{~μ 3.}
On the other hand, when it is determined that the light absorption coefficient calculation unit 109 has calculated the light absorption coefficients μ _{1 to} μ ₃ of the wavelengths λ _{1 to} λ ₄ (step S17: YES), the concentration calculation unit 110 calculates the equation ( Based on 7), the concentration of glucose contained in the dermis layer is calculated (step S18).

According to the present embodiment, the absorption coefficients μ _{1 to} μ ₃ are calculated by the integrated value of the optical path length during the time τ. Thus, it is possible to reduce the influence on the calculation result of the absorption coefficient μ ₁ ~μ ₃ by the error contained in the measured received light intensity I (t).

Although the first embodiment and the second embodiment have been described with reference to the drawings, the specific configuration is not limited to the above-described one, and various modifications can be made without departing from the gist of the present invention. It is possible to change the design.
For example, in the first embodiment and the second embodiment, the case where the concentration quantification method is implemented in the blood glucose level measuring apparatus 100 and the concentration of glucose contained in the dermis layer of the skin is measured has been described. Instead, the concentration quantification method may be used for another apparatus for quantifying the concentration of the target component in an arbitrary layer to be observed formed from a plurality of layers.

  In the first embodiment and the second embodiment, the blood sugar level measuring apparatus 100 includes the simulation unit 101, the optical path length distribution storage unit 102, and the time-resolved waveform storage unit 103. If the simulation result in the unit 101 is stored in the optical path length distribution storage unit 102 and the time-resolved waveform storage unit 103, it is not necessary to provide the simulation unit 101 separately.

  The blood glucose level measuring apparatus 100 described above may be configured to include a computer system inside. The operation of each processing unit described above or a part of the operation of each processing unit is stored in a computer-readable recording medium in the form of a program, and the computer reads and executes the program to execute the above processing. Is done. Here, the computer-readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, and the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

The program may be for realizing a part of the functions described above.
Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, what is called a difference file (difference program) may be sufficient.

[Third Embodiment]
FIG. 8 is a schematic block diagram showing the configuration of the blood sugar level measuring apparatus according to the third embodiment of the present invention.
The blood glucose level measuring apparatus 200 of the present embodiment is different from the blood glucose level measuring apparatus 100 of the first embodiment in that the blood glucose level measuring apparatus 200 of the present embodiment includes an irradiation unit 104, a light receiving unit 105, and a computer system. 201, the computer system 201 includes a storage unit 202 and a control unit (CPU) 203, and the storage unit 202 stores an optical path length distribution storage unit 102 that stores a simulation result in the simulation unit 101 and a time. The control unit (CPU) 203 executes the function of the decomposed waveform storage unit 103, and the measurement light intensity acquisition unit 106, the optical path length acquisition unit 107, the non-absorption light intensity acquisition unit 108, the light absorption coefficient calculation unit 109, and the concentration calculation unit. The point is that 110 functions are executed.

  Also in the blood sugar level measuring apparatus 200 of the present embodiment, the same actions and effects as the blood sugar level measuring apparatus 100 of the first embodiment can be achieved.

[Fourth Embodiment]
FIG. 9 is a schematic block diagram showing the configuration of the blood sugar level measuring apparatus according to the fourth embodiment of the present invention.
This blood glucose level measuring apparatus 300 is a device that non-invasively quantifies the concentration of glucose (target component) contained in the dermis layer (arbitrary layer) of a plurality of layers constituting skin (observation target) such as a palm. Yes, a simulation unit 301, an optical path length distribution storage unit 302, a time-resolved waveform storage unit 303, an irradiation unit 304, a light receiving unit 305, a measured light intensity acquisition unit (light intensity acquisition unit) 306, and an optical path length acquisition Unit 307, non-absorption light intensity acquisition unit (light intensity model acquisition unit) 308, integration interval calculation unit 309, light absorption coefficient calculation unit 310, light absorption coefficient distribution storage unit 311, and light absorption coefficient acquisition unit 312. And a density calculation unit 313.

The simulation part 301 performs the simulation which irradiates light with respect to the skin model whose light absorption coefficient is zero.
The optical path length distribution storage unit 302 stores a model of the optical path length distribution in each layer constituting the skin of short-time pulse light irradiated to the skin. Here, the optical path length distribution of the skin model with zero light absorption coefficient is stored.
Here, the short-time pulsed light is pulsed light whose pulse width is shorter than the time during which light travels directly from the irradiation unit 304 to the light receiving unit 305 in the air. 0.1 ps to 10 ps refers to pulsed light having a time interval of 1 ps to 100 ps between two pulsed lights.
The optical path length distribution is a distribution function representing the length (optical path length) of the movement path of light (photon) based on the time until the light (photon) reaches the light receiving unit 305.

  The optical path length acquisition unit 307 acquires from the optical path length distribution storage unit 302 the optical path length of each layer of the skin at a predetermined time of the optical path length distribution model. Here, the optical path length at a certain time is acquired from the optical path length distribution storage unit 302. The optical path length here refers to the length of the light path from when the short-time pulsed light emitted from the irradiation unit 304 enters the skin and is scattered in the skin and detected by the light receiving unit 305. As will be described later, the optical path length of each layer of the skin is estimated by setting the distance between the irradiation unit 304 and the light receiving unit 305.

The time-resolved waveform storage unit 303 stores a model of a time-resolved waveform of short-time pulsed light that is applied to the skin. Here, the time-resolved waveform of the skin model having zero light absorption coefficient is stored. Here, the time-resolved waveform of the short-time pulsed light is the intensity of light (photons) received by the light receiving unit 305 expressed as a distribution function based on the elapsed time from the irradiation of the short-time pulsed light. It is.
The non-absorptive light intensity acquisition unit 308 reads from the time-resolved waveform storage unit 303 when the light absorption coefficient at a predetermined time of the time-resolved waveform model of the short-time pulse light is zero (no absorption). Get the light intensity. Here, the non-absorption light intensity at a certain time is acquired from the time-resolved waveform storage unit 303.

The irradiation unit 304 irradiates the skin with short-time pulsed light. This light is scattered by the tissue in the skin and diffuses into the skin. Part of the diffused light reaches the light receiving unit 305 (backscattered light). The path through which the backscattered light that has reached the light receiving unit 305 has propagated in the skin is a banana-shaped path as shown in FIG. The plurality of short-time pulse lights emitted by the irradiating unit 304 is light having a wavelength that increases the orthogonality of the absorption spectrum distribution of each component of the main component constituting the skin, that is, each of the main component constituting the skin. Among the components, the maximum value of the absorption spectrum of a specific component in a certain main component includes light having a wavelength that is significantly different from the maximum value of the absorption spectrum of another component.
The light receiving unit 305 receives light obtained by backscattering short-time pulsed light by the skin. The light receiving unit 305 includes an internal memory (not shown) that records the light reception intensity. The internal memory may be replaced with an external memory that is electrically connected to the light receiving unit 305.

  There is a certain relationship between the distance W between the entrance and exit of the irradiation unit 304 and the light receiving unit 305 and the penetration depth of the light R entering the skin. Therefore, by defining the distance W between the light input and output between the irradiation unit 304 and the light receiving unit 305, the penetration depth of the light R entering the skin is also uniquely determined. For example, if the distance W between incident and outgoing is 10 mm, the penetration depth of the light R is 10 mm, and if the distance W between incoming and outgoing is 0.8 mm, the penetration depth of the light R is 0.8 mm.

When the light receiving unit 305 receives the backscattered light, the measurement light intensity acquisition unit 306 has a plurality of times t _{1 to} t _{m that} are equal to or more than the number n of each layer of the skin in the integration interval of the light received by the light receiving unit 305. Is obtained (where n is a natural number of 1 or more and m is a natural number of n or more). The plurality of times when the measurement light intensity acquisition unit 306 acquires the light intensity includes the peak time of the optical path length distribution of each layer of the skin.
The integration interval calculation unit 309 includes the optical path length of each skin layer of the model of the optical path length distribution acquired by the optical path length acquisition unit 307 and the time-resolved waveform of the short-time pulse light acquired by the non-absorption light intensity acquisition unit 308. Based on the light intensity at the time of non-absorption of the model and the light intensity distribution received by the light receiving unit 305 acquired by the measurement light intensity acquisition unit 306, the integration of the region corresponding to the light intensity of each layer of the skin from the light intensity distribution Calculate the interval.

Here, the integration interval is a time width of a region corresponding to the light intensity of an arbitrary layer in the light intensity distribution, and can be determined by the start time, the end time, and the increment time.
For example, (1) the light intensity output from the light receiving unit 305 that receives the backscattered light is detected with the light intensity equal to the minimum detection sensitivity from the time when the light intensity detected exceeds the minimum detection sensitivity of the measurement light intensity acquisition unit 306 Time to time, (2) time characteristics of non-absorbing light intensity acquired from the time-resolved waveform storage unit 303 storing the non-absorbing light intensity obtained by the simulation unit 301, and (3) a light receiving unit 305 in contact with the skin surface. (4) The start time of the integration interval using the size and optical characteristics (scattering coefficient, absorption coefficient, anisotropic parameter, or refractive index) of the skin model given to the simulation unit 301 Determine the end time and increment time.

The light absorption coefficient calculation unit 310 calculates the light absorption coefficient of each layer of the skin based on the integration interval calculated by the integration interval calculation unit 309.
Here, the light absorption coefficient and the estimated error rate of each layer of the skin in the integration interval determined by the integration interval calculation unit 309 are obtained, and the distribution of the light absorption coefficient and the estimated error rate of each layer of the skin with respect to the integration interval is calculated.
In this light absorption coefficient calculation unit 310, the light absorption coefficient of each layer in the skin is calculated from the following equation (9).

Where ln (A) is the natural logarithm of A, I (t) is the light intensity received by the light receiving unit 305 at time t, and N (t) is a model of the time-resolved waveform of the short-time pulsed light with the specific wavelength λk. The light intensity at time t, Li (t) represents the optical path length of the i-th layer at time t in the model of the optical path length distribution in each layer of the skin, and μi represents the light absorption coefficient of the i-th layer.
Here, the first layer is the epidermis layer, the second layer is the dermis layer, the third layer is the subcutaneous tissue, μ ₁ is the light absorption coefficient of the epidermis layer, μ ₂ is the light absorption coefficient of the dermis layer, and μ ₃ is the subcutaneous Shows the light absorption coefficient of tissue.

The light absorption coefficient distribution storage unit 311 stores the distribution of the light absorption coefficient and the estimated error rate of an arbitrary layer for the integration interval calculated by the light absorption coefficient calculation unit 310.
The light absorption coefficient acquisition unit 312 includes the distribution of the light absorption coefficient and the estimated error rate of an arbitrary layer with respect to the integration interval acquired from the light absorption coefficient distribution storage unit 311, the range of the light absorption coefficient variation rate with respect to the change in the integration interval, A light absorption coefficient based on the glucose concentration corresponding to blood glucose in the skin main component of the layer at a specific depth from the surface of the skin is obtained using the reference.

The concentration calculation unit 313 is included in the layer at the specific depth from the light absorption coefficient based on the glucose concentration corresponding to blood glucose in the skin main component of the layer at the specific depth from the skin surface acquired by the light absorption coefficient acquisition unit 312. The concentration of glucose is calculated.
In the concentration calculation unit 313, the glucose concentration in an arbitrary layer of the skin is calculated from the following equation (10).

Where μa is the light absorption coefficient in the a layer, which is an arbitrary layer of the skin, gj is the molar concentration of the jth component constituting the skin, εj is the light absorption coefficient of the jth component, and p is the main component constituting the skin Q represents the number of types of the specific wavelength λk.
Here, the first layer is the epidermis layer, the second layer is the dermis layer, the third layer is the subcutaneous tissue, μ ₁ is the light absorption coefficient of the epidermis layer, μ ₂ is the light absorption coefficient of the dermis layer, and μ ₃ is the subcutaneous Shows the light absorption coefficient of tissue.

In the blood glucose level measuring apparatus 300, the irradiation unit 304 irradiates the skin with a short-time pulse light, and the light receiving unit 305 receives the light back-scattered by the skin with the short-time pulse light, and the measurement light intensity acquisition unit. 306 acquires the light intensity received by the light receiving unit 305 at time t.
Next, the optical path length acquisition unit 5 acquires the optical path length of each layer of the skin at time t of the optical path length distribution in the skin model from the optical path length distribution storage unit 4, and the non-absorption light intensity acquisition unit 308 stores the time-resolved waveform memory. The light intensity at time t of the time-resolved waveform of the short-time pulse light in the skin model is acquired from the unit 303.

  Next, the integration interval calculation unit 309 includes the optical path length of each layer of the model skin of the optical path length distribution acquired by the optical path length acquisition unit 307, for example, the optical path length acquired from the optical path length distribution storage unit 302, and the non-absorbing light. The light intensity in the time-resolved waveform model of the short-time pulse light acquired by the intensity acquisition unit 308, for example, the light intensity acquired from the time-resolved waveform storage unit 303, and the light receiving unit 305 acquired by the measurement light intensity acquisition unit 306 receive light. Based on the light intensity distribution, an integration interval of a region corresponding to the light intensity of an arbitrary layer is calculated from the light intensity distribution.

  For example, (1) the light intensity output from the light receiving unit 305 that receives the backscattered light is detected with the light intensity equal to the minimum detection sensitivity from the time when the light intensity detected exceeds the minimum detection sensitivity of the measurement light intensity acquisition unit 306 Time to time, (2) time characteristics of non-absorbing light intensity acquired from the time-resolved waveform storage unit 303 storing the non-absorbing light intensity obtained by the simulation unit 301, and (3) a light receiving unit 305 in contact with the skin surface. (4) The size of the skin model given to the simulation unit 301 and the optical characteristics (scattering coefficient, absorption coefficient, anisotropic parameter, or refractive index), the start time of the integration interval, Determine the end time and increment time.

Next, the light absorption coefficient calculation unit 310 obtains the light absorption coefficient and estimated error rate of an arbitrary layer in the integration interval determined by the integration interval calculation unit 309, and calculates the light absorption coefficient and estimated error rate of the arbitrary layer with respect to the integration interval. The distribution of is calculated.
Next, the light absorption coefficient distribution storage unit 311 stores the distribution of the light absorption coefficient and the estimated error rate of an arbitrary layer for the integration interval calculated by the light absorption coefficient calculation unit 310.
Next, the light absorption coefficient acquisition unit 312 distributes the light absorption coefficient and the estimated error rate of an arbitrary layer with respect to the integration interval acquired from the light absorption coefficient distribution storage unit 311 and the range of the light absorption coefficient variation rate with respect to the change in the integration interval. Is used to obtain a light absorption coefficient based on a glucose concentration corresponding to blood glucose in the skin main component of the layer at a specific depth from the surface of the skin.

  Next, the concentration calculation unit 313 calculates the light absorption coefficient based on the light absorption coefficient based on the glucose concentration corresponding to blood glucose in the skin main component of the layer at the specific depth from the skin surface acquired by the light absorption coefficient acquisition unit 312. The concentration of glucose contained in the layer at the specific depth is calculated based on the above equation (10).

  As described above, in this blood glucose level measuring apparatus 300, the glucose concentration is calculated using the light absorption coefficient of the dermis layer which is a layer having a specific depth in the skin, so that the influence of noise caused by layers other than the dermis layer can be reduced. It is possible to accurately calculate the concentration of glucose contained in the dermis layer which is a layer having a specific depth.

  Further, based on the integration interval calculated by the integration interval calculation unit 309, the light absorption coefficient of glucose contained in the dermis layer that is a layer having a specific depth in the time zone corresponding to the integration interval is acquired. It is possible to reduce the influence of light from other layers on the light. Therefore, the light absorption amount of glucose contained in the layer having a specific depth, that is, the glucose concentration can be measured noninvasively with high accuracy.

Next, the operation of the blood sugar level measuring apparatus 300 will be described.
The blood glucose level measuring apparatus 300 needs to calculate the optical path length distribution and the time-resolved waveform in each layer of the skin model in advance before measuring the blood glucose level.
Here, a method for calculating the optical path length distribution and time-resolved waveform of the skin model will be described.
First, the simulation unit 301 generates a skin model. The skin model is generated by determining the light scattering coefficient, light absorption coefficient, and thickness of each layer of the skin. Here, if the skin portion is specified, the scattering coefficient and thickness of each layer in the specified skin portion are small depending on the individual, so it may be determined by taking a sample in advance. The thickness of the epidermis layer 32 is approximately 0.3 mm, the thickness of the dermis layer 33 is approximately 1.2 mm, and the thickness of the subcutaneous tissue 34 is approximately 3.0 mm.
The light absorption coefficient of the skin model used here is zero. The reason is that the amount of light absorption is calculated using this skin model.

When the simulation unit 301 generates a skin model, the simulation unit 301 performs a simulation of irradiating the skin model with light. At this time, it is necessary to determine the distance between the position of the irradiation unit 304 and the position of the light receiving unit 305. The simulation is performed using, for example, a Monte Carlo method.
The simulation by the Monte Carlo method is performed as follows, for example.

  First, the simulation unit 301 uses a model of light to be irradiated as a photon (light beam), and performs calculation to irradiate the skin model with the photon. Photons irradiated to the skin model move in the skin model. At this time, the photon determines the distance L and the direction θ to the next advancing point by the random number R. The simulation unit 301 calculates the distance L to the point where the photon advances next by Expression (11).

Here, ln (A) represents the natural logarithm of A, and μs represents the scattering coefficient of the s-th layer (any one of the epidermis layer, dermis layer, and subcutaneous tissue layer) of the skin model.
In addition, the simulation unit 301 calculates the direction θ up to the point where the photon advances next by Expression (12).

However, g shows the anisotropic parameter which is the average of the cosine (cos) of a scattering angle, and the anisotropic parameter of skin is about 0.9.
The simulation unit 301 can calculate the movement path of photons from the irradiation unit 304 to the light receiving unit 305 by repeating the calculations of the equations (11) and (12) every unit time. The simulation unit 301 calculates the movement distance for a plurality of photons. For example, the simulation unit 301 calculates the movement distance for 10 ⁸ photons.

The simulation unit 301 classifies the movement path of each photon that has reached the light receiving unit 305 for each layer through which the movement path passes. Then, the simulation unit 301 calculates the optical path length distribution of each layer of the skin as shown in FIG. 3 by calculating the average length of the moving path of the photons reached every unit time for each classified layer. To do.
Moreover, the simulation part 301 calculates the time-resolved waveform of the skin model as already shown in FIG. 4 by calculating the number of photons reaching the light receiving part 305 every unit time.

FIG. 10 is a diagram showing a time-resolved waveform of non-absorption light intensity (equal to the number of received photons) N (t) obtained by the simulation unit 301, and FIG. FIG. 12 is a diagram showing the time-resolved waveform of t) on a linear scale, and FIG. 12 is a diagram showing the time-resolved waveform on a log scale. 11 and 12, a three-layer skin model of the epidermis layer, the dermis layer, and the subcutaneous tissue is used, and the absorption coefficient of the epidermis is changed from 25% to 150% with respect to the absorption coefficient of the dermis. 11 and 12, A indicates 25%, B indicates 50%, C indicates 75%, D indicates 100%, E indicates 125%, and F indicates 150%.
10 to 12, it can be seen that the amplitude with respect to the value (peak value) at which the number of photons or the light intensity becomes maximum at about 30 ps is 5% or less, which is close to the true value.
Further, according to FIGS. 11 and 12, at about 50 ps, when the absorption coefficient of the epidermis is 25% with respect to the absorption coefficient of the dermis layer, the peak value is reduced by about three orders of magnitude. I understand.

  Through the processing described above, the simulation unit 301 calculates the optical path length distribution and time-resolved waveform of the skin model for a plurality of wavelengths. At this time, the simulation unit 301 may calculate an optical path length distribution and a time-resolved waveform for a wavelength having a large difference in absorption spectrum of skin main components (water, protein, lipid, glucose, etc.).

  Regarding the absorption spectrum of the main component of the skin, as already explained in FIG. 5, the absorption coefficient of glucose becomes maximum when the wavelength is 1600 nm, and the absorption coefficient of water becomes maximum when the wavelength is 1450 nm. . For this purpose, the simulation unit 301, for example, 1450 nm, 1600 nm, and the like, each of the light components having a wavelength that increases the orthogonality of the absorption spectrum distribution of each component of the main component constituting the skin, that is, each of the main components constituting the skin. Among these components, it is preferable to calculate the optical path length distribution and the time-resolved waveform for light having a wavelength at which the maximum value of the absorption spectrum of a specific component in a certain main component is significantly different from the maximum value of the absorption spectrum of another component.

  When the simulation unit 301 calculates the optical path length distribution and time-resolved waveform of the skin model for a plurality of wavelengths, the optical path length distribution storage unit 302 stores information on the calculated optical path length distribution, and the time-resolved waveform storage unit 303 Information on the calculated time-resolved waveform is stored.

Next, the operation of the blood glucose level measuring apparatus 300 for measuring the blood glucose level will be described with reference to FIGS.
First, when the measurement subject puts the blood sugar level measuring device 300 on the skin such as the wrist and operates the blood sugar level measuring device 300 by pressing a measurement start switch (not shown) or the like, the irradiation unit 304 is applied to the skin. irradiating the short pulse light having a wavelength lambda _k (step S21).
As the wavelength λ _k , for example, one of a plurality of wavelengths for which the simulation unit 301 has calculated the optical path length distribution and the time-resolved waveform is preferable.
For example, among the main components constituting the skin, light having a wavelength at which the light absorption coefficient of a specific component in one main component is larger than the light absorption coefficient of another component, that is, the minimum value of the light absorption coefficient of a specific component is It is preferable to calculate the optical path length distribution and the time-resolved waveform for light having a wavelength significantly different from the minimum value of the light absorption coefficient of the component.

When the irradiation unit 304 irradiates the short pulse light having a wavelength lambda _k, the light receiving portion 305 receives the light backscattered by the skin is irradiated from the irradiation unit 304 (step S22).
At this time, the light receiving unit 305 records the received light intensity for each unit time from the start of irradiation (for example, times t _{1 to} t _m every 1 picosecond) in an internal memory (not shown).

Next, the light absorption coefficient of the dermis layer is calculated by changing the integration interval (process A; step S23).
This step S23 is performed by the operation shown in FIG.
First, the integration interval calculation unit 309 (1) determines the minimum detection sensitivity from the time when the light intensity output from the light receiving unit 305 that receives the backscattered light exceeds the minimum detection sensitivity of the measurement light intensity acquisition unit 306. Time until time detected with equal light intensity, (2) time characteristics of non-absorption light intensity acquired from the time-resolved waveform storage unit 303 storing the non-absorption light intensity obtained by the simulation unit 301, (3) Using the distance between the light receiving unit 305 and the irradiation unit 304 in contact with the skin surface, and (4) the size and optical characteristics (scattering coefficient, absorption coefficient, anisotropic parameter, or refractive index) of the skin model given to the simulation unit 301 Calculate the integration interval. More specifically, the start time, end time, and increment time of the integration interval are calculated (step S31).

  FIG. 15 is a diagram showing the relationship between the light absorption coefficient and the integration interval in the dermis layer. In FIG. 15, a three-layer skin model of the epidermis layer, the dermis layer, and the subcutaneous tissue is used, and the absorption coefficient of the epidermis layer is changed from 25% to 150% with respect to the absorption coefficient of the dermis layer. In FIG. 15, A indicates 25%, B indicates 50%, C indicates 75%, D indicates 100%, E indicates 125%, and F indicates 150%.

  According to FIG. 15, in the range of 14 ps to 34 ps, when the values of the light absorption coefficient of the epidermis layer and the dermis layer approach, a value close to 0.55 / mm which is a value of the true light absorption coefficient given in advance. It can be seen that It can also be seen that there is a tendency to increase and have a peak in the range of 34 ps to 54 ps. Thus, it can be seen that as the integration interval becomes wider, the value of the light absorption coefficient of the dermis layer converges in a specific range (0.54 to 0.56 / mm in FIG. 15).

Next, when the light receiving unit 305 completes the light reception, the measurement light intensity acquisition unit 306 acquires the received light intensity at a certain time t by the same number as the number of skin layers from the received light intensity recorded in the internal memory (step). S32).
For example, when concentration measurement is performed on three layers of skin using four types of wavelengths, received light intensity I (t ₁ ) to I (t ₃ ) at _three different times t _{1 to} t ₃ is acquired. Here, the reason why the received light intensity is obtained in the same number as the number of skin layers is to calculate the absorption coefficient of each skin layer by simultaneous equations in the processing described later.

In addition, the times t ₁ to t _{3 at} which the measurement light intensity acquisition unit 306 acquires the light intensity may be a time at which the optical path length distribution of each layer of the skin becomes a peak. That is, the light intensity at the time obtained by adding the time when the optical path length of each layer of the skin in FIG.

When the measurement light intensity acquisition unit 306 acquires the light reception intensities I (t ₁ ) to I (t ₃ ), the optical path length acquisition unit 307 calculates the optical path length distribution of the wavelength λ ₁ stored in the optical path length distribution storage unit 302 from time _t 1 the optical path length of each layer of the skin at _{~t 3 L 1 (t 1)} ~L 1 (t 3), L 2 (t 1) ~L 2 (t 3), L 3 (t 1) ~L 3 (T ₃ ) is acquired (step S33).
In addition, when the measurement light intensity acquisition unit 306 acquires the received light intensity I (t ₁ ) to I (t ₃ ), the non-absorption light intensity acquisition unit 308 stores the time of the wavelength λ ₁ stored in the time-resolved waveform storage unit 303. light intensity at a predetermined time model from degradation waveform, time-resolved waveform of the short pulse light, for example, detecting the number of photons at a time _t 1 ~t ₃ (no absorption at the light _{intensity) N (t 1) ~N (} t 3 ) Is acquired (step S34).

When the optical path length acquisition unit 307 acquires the optical path length of each layer of the skin, and the non-absorption light intensity acquisition unit 308 acquires the number of detected photons (non-absorption light intensity) N (t ₁ ) to N (t ₃ ), the light absorption. The coefficient calculation unit 310 calculates the light absorption coefficients μ _{1 to} μ ₃ of each layer of the skin in a certain integration interval calculated by the integration interval calculation unit 309 based on the equation (13) (step S35). Here, the light absorption coefficient μ ₁ indicates the light absorption coefficient of the epidermis layer, the light absorption coefficient μ ₂ indicates the light absorption coefficient of the dermis layer, and the light absorption coefficient μ ₃ indicates the light absorption coefficient of the subcutaneous tissue layer. Show.

Here, ln (A) represents the natural logarithm of A, and N (t) represents the light intensity at the time t of the model of the time-resolved waveform of the short-time pulsed light with the specific wavelength λk. I _in indicates the light intensity of the short-time pulsed light irradiated by the irradiation unit 304. N _in indicates the number of photons on which the simulation unit 301 has simulated the irradiation.

When the light absorption coefficient calculation unit 310 calculates the light absorption coefficient μ _{1 to} μ ₃ of each skin layer in an integration interval, the light absorption coefficient distribution storage unit 311 calculates a certain integration interval calculated by the light absorption coefficient calculation unit 310. The light absorption coefficient μ _{1 to} μ ₃ of each layer of the skin is stored (step S36).

When the light absorption coefficient calculation unit 310 calculates the light absorption coefficient μ _{1 to} μ ₃ of each layer of the skin in an integration interval, the light absorption coefficient calculation unit 310 calculates the light absorption coefficient of the dermis layer 33 in the set integration interval. It is determined whether or not it has been calculated (step S37).
In this embodiment, blood sugar levels are measured with four main components of skin, water, protein, lipid, and glucose, so that the light absorption coefficient calculator 310 emits light for _four wavelengths λ _{1 to} λ ₄ . It is determined whether or not the absorption coefficients μ _{1 to} μ ₃ are calculated. Here, the wavelengths λ _{1 to} λ ₄ are selected from a plurality of wavelengths calculated by the simulation unit 301 for the optical path length distribution and the time-resolved waveform.

Here, when it is determined that there is a light absorption coefficient that is not calculated in the light absorption coefficient μ _{1 to} μ ₃ of the dermis layer in the integration interval set by the light absorption coefficient calculation unit 310 (step S37: NO), Returning to the acquisition of the received light intensity at a certain time (step S32), the light absorption coefficient of the dermis layer that has not yet been calculated is calculated, and it is determined again whether or not the light absorption coefficient of the dermis layer can be calculated in the set integration interval ( Step S37) is performed.
On the other hand, when it is determined that the light absorption coefficient μ _{1 to} μ ₃ of the dermis layer is calculated in the integration interval set by the light absorption coefficient calculation unit 310 (step S37: YES), light absorption is performed from the light absorption coefficient distribution of the dermis layer. A coefficient is acquired (step 38).

The light absorption coefficient acquisition unit 312 determines whether or not the light absorption coefficient having the number of wavelengths corresponding to the number of types of the main components of the skin has been calculated (step S24).
Here, when it is determined that the light absorption coefficient acquisition unit 312 has not calculated the light absorption coefficient of the number of wavelengths corresponding to the number of types of main components of the skin (step S24: NO), irradiation with short-time pulse light (step S24) Returning to S21), the light absorption coefficient of the number of wavelengths corresponding to the number of types of the main component of the skin that has not yet been calculated is calculated, and it is determined again whether or not the light absorption coefficient can be calculated (step S24).

On the other hand, when it is determined that the light absorption coefficient acquisition unit 312 has calculated the light absorption coefficient of the number of wavelengths corresponding to the number of types of the main components of the skin (step S24: YES), the concentration calculation unit 313 includes glucose contained in the dermis layer. Is calculated (step S25).
The concentration calculation unit 313 calculates the glucose concentration in the dermis layer by the following equation (14).

_{However, μ 2 (1) ~μ 2} (4) shows the optical absorption coefficient of the wavelength lambda ₁ to [lambda] ₄ in the dermis layer. Further, g ₁ to g ₄ shows the water respectively in the dermal layer is the main component of skin, proteins, lipids, the molar concentration of glucose. _{Further, ε 1 (1) ~ε 1} (4) shows a molar extinction coefficient of water with respect to the wavelength _{λ 1 ~λ 4, ε 2 (} 1) ~ε 2 (4) is for the wavelength lambda ₁ to [lambda] ₄ Indicates the molar extinction coefficient of the protein, ε _{3 (1) to} ε _{3 ( 4)} indicate the molar extinction coefficient of the lipid for wavelengths λ _{1 to} λ ₄ , and ε _{4 (1) to} ε _{4 (4)} indicate the wavelength The molar extinction coefficient of glucose with respect to λ _{1 to} λ ₄ is shown.
That is, the molar concentration of glucose contained in the dermis layer can be obtained by calculating g ₄ in the equation (14).

  Here, the reason why the molar concentration of glucose can be obtained from the equation (14) will be described. Since the wavelength dependence of the skin scattering coefficient is small, changes in the number of detected photons N (t) and the optical path length Ln (t) with respect to the wavelength can be ignored. Further, it can be expressed as Absorbance = Molar extinction coefficient × Molar concentration according to the Beer-Lambert law. Thus, by eliminating the detected photon number N (t) from time-resolved measurement obtained at two wavelengths, the relational expression between the absorption coefficient difference obtained in the dermis layer and the molar absorption coefficient of each component forming the skin Equation (14) showing can be derived.

The blood glucose level measuring apparatus 300 described above has a computer system (not shown) therein, and the processing operation of each step described above is stored in a computer-readable recording medium in the form of a program. Therefore, the computer can read out and execute this program to perform the above processing operation.
Here, examples of the computer-readable recording medium include a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, and a semiconductor memory.
Further, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

The program may be for realizing a part of the functions.
Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, what is called a difference file (difference program) may be sufficient.

As described above, according to the present embodiment, the integration interval calculation unit 309 performs the optical path length of each layer of the model skin of the optical path length distribution acquired by the optical path length acquisition unit 307 and the non-absorption light intensity acquisition unit. Based on the non-absorption light intensity of the model of the time-resolved waveform of the short-time pulse light acquired by 308 and the light intensity distribution received by the light receiving unit 305 acquired by the measurement light intensity acquisition unit 306, the light intensity distribution is used to determine the dermis. Since the integration interval of the region corresponding to the light intensity of the layer is calculated, based on the integration interval calculated by the integration interval calculation unit 309, the time zone corresponding to the integration interval is determined from the intensity of the light received by the light receiving unit 305. By obtaining the light intensity, light from the dermis layer can be measured separately from light from other layers, and the influence of light from other layers on the light from the dermis layer can be reduced. . Therefore, the glucose concentration in the dermis layer can be accurately measured, and as a result, the glucose concentration in the dermis layer can be quantified non-invasively and accurately.
Moreover, the measurement accuracy of the glucose concentration in the dermis layer can be increased by varying the integration interval.

  In the present embodiment, the simulation unit 301 performs a simulation of irradiating light to a skin model having a zero light absorption coefficient. However, the simulation unit 301 uses a skin model having a zero light absorption coefficient. If the simulation result of irradiating light is stored in the optical path length distribution storage unit 302 and the time-resolved waveform storage unit 303, the same operations and effects as the present embodiment can be obtained without the simulation unit 301. be able to.

[Fifth Embodiment]
FIGS. 16 and 17 are flowcharts showing an operation in which the blood sugar level measuring apparatus (concentration quantifying apparatus) according to the fifth embodiment of the present invention measures the blood sugar level.
The blood sugar level measuring apparatus of the present embodiment has the same configuration as the blood sugar level measuring apparatus 300 of the third embodiment, and includes an optical path length acquisition unit 307, a non-absorption light intensity acquisition unit 308, a measurement light intensity acquisition unit 306, and light. The operation of the absorption coefficient calculation unit 310 is different.

Next, the operation in which the blood sugar level measuring apparatus of this embodiment measures the blood sugar level will be described.
First, when the measurement subject puts the blood sugar level measuring device 300 on the skin such as the wrist and operates the blood sugar level measuring device 300 by pressing a measurement start switch (not shown) or the like, the irradiating unit 304 applies to the skin 31. Te is irradiated with short pulse light having a wavelength lambda _k (step S41).
As the wavelength λ _k , for example, one of a plurality of wavelengths for which the simulation unit 301 has calculated the optical path length distribution and the time-resolved waveform is preferable.

When the irradiation unit 304 irradiates the short pulse light having a wavelength lambda _k, the light receiving portion 305 receives the light backscattered by the skin 31 is irradiated from the irradiation unit 304 (step S42).
At this time, the light receiving unit 305 records the received light intensity for each unit time from the start of irradiation (for example, times t _{1 to} t _m every 1 picosecond) in an internal memory (not shown).

Next, the light absorption coefficient of the dermis layer is calculated by changing the integration interval (process B: step S43).
This step S43 is performed by the operation shown in FIG.
First, the integration interval calculation unit 309 (1) determines the minimum detection sensitivity from the time when the light intensity output from the light receiving unit 305 that receives the backscattered light exceeds the minimum detection sensitivity of the measurement light intensity acquisition unit 306. Time until time detected with equal light intensity, (2) time characteristics of non-absorption light intensity acquired from the time-resolved waveform storage unit 303 storing the non-absorption light intensity obtained by the simulation unit 301, (3) Using the distance between the light receiving unit 305 and the irradiation unit 304 in contact with the skin surface, and (4) the size and optical characteristics (scattering coefficient, absorption coefficient, anisotropic parameter, or refractive index) of the skin model given to the simulation unit 301 Calculate the integration interval. More specifically, the start time, end time, and increment time of the integration interval are calculated (step S51).

Next, when the light receiving unit 305 completes the light reception, the measurement light intensity acquisition unit 306 acquires the time distribution of the light reception intensity from a certain time to the time τ from the light reception intensity recorded in the internal memory of the light reception unit 305. (Step S52).
For example, when concentration measurement is performed for three layers of skin using four types of wavelengths, time distributions of received light intensity at _three different times τ _{1 to} τ ₃ are acquired.

When the measurement light intensity acquisition unit 306 acquires the time distribution of the received light intensity during the time τ, the optical path length acquisition unit 307 starts from the optical path length distribution of the wavelength λ ₁ stored in the optical path length distribution storage unit 302 from a certain time. The optical path length of each layer of the skin during time τ, for example, optical path lengths L ₁ (t ₁ ) to L ₁ (t ₃ ), L ₂ (t ₁ ) to L ₂ (t ₃ ), L ₃ (t ₁ ) ~L ₃ acquires _{(t 3)} (step S53).
In addition, when the measurement light intensity acquisition unit 306 acquires the time distribution of the received light intensity during the time τ, the non-absorption light intensity acquisition unit 308 uses the time-resolved waveform of the wavelength λ ₁ stored in the time-resolved waveform storage unit 303. The non-absorption light intensity between a certain time and the time τ, for example, the number of detected photons (non-absorption light intensity) N (t ₁ ) to N (t ₃ ) between the certain time and the time τ is acquired (step S54). ).

When the optical path length acquisition unit 307 acquires the optical path length of each layer of the skin, and the non-absorption light intensity acquisition unit 308 acquires the number of detected photons (non-absorption light intensity) N (t ₁ ) to N (t ₃ ), the light absorption. The coefficient calculation unit 310 calculates the light absorption coefficients μ _{1 to} μ ₃ of each layer of the skin in a certain integration interval calculated by the integration interval calculation unit 309 based on Expression (15) (step S55). Here, the light absorption coefficient μ ₁ indicates the light absorption coefficient of the epidermis layer, the light absorption coefficient μ ₂ indicates the light absorption coefficient of the dermis layer, and the light absorption coefficient μ ₃ indicates the light absorption coefficient of the subcutaneous tissue layer. Show.

Here, ln (A) represents the natural logarithm of A. Further, I (t) represents the light reception intensity of the light receiving unit 305 at time t, and I _in represents the light intensity of the short-time pulsed light irradiated by the irradiation unit 304. N (t) represents the number of detected photons at time t of the time-resolved waveform, and N _in represents the number of photons on which the simulation unit 301 has simulated the irradiation. L ₁ (t) to L ₃ (t) indicate the optical path length of each layer of the skin at time t.

When the light absorption coefficient calculation unit 310 calculates the light absorption coefficient μ _{1 to} μ ₃ of each skin layer in an integration interval, the light absorption coefficient distribution storage unit 311 calculates a certain integration interval calculated by the light absorption coefficient calculation unit 310. The light absorption coefficients μ _{1 to} μ ₃ of each layer of the skin are stored (step S56).

When the light absorption coefficient calculation unit 310 calculates the light absorption coefficient μ _{1 to} μ ₃ of each layer of the skin in an integration interval, the light absorption coefficient calculation unit 310 calculates the light absorption coefficient of the dermis layer in the set integration interval. It is determined whether or not it has been done (step S57).
In this embodiment, blood sugar levels are measured with four main components of skin, water, protein, lipid, and glucose, so that the light absorption coefficient calculator 310 emits light for _four wavelengths λ _{1 to} λ ₄ . It is determined whether or not the absorption coefficients μ _{1 to} μ ₃ are calculated. Here, the wavelengths λ _{1 to} λ ₄ are selected from a plurality of wavelengths calculated by the simulation unit 301 for the optical path length distribution and the time-resolved waveform.

Here, when it is determined that the light absorption coefficient μ _{1 to} μ ₃ of the dermis layer in the integration interval set by the light absorption coefficient calculation unit 310 is not calculated (step S57: NO), again, Returning to the acquisition of the received light intensity at a certain time (step S52), the light absorption coefficient of the dermis layer that has not been calculated yet is calculated, and it is determined again whether or not the light absorption coefficient of the dermis layer can be calculated in the set integration interval ( Step S57) is performed.
On the other hand, when it is determined that the light absorption coefficient μ _{1 to} μ ₃ of the dermis layer has been calculated in the integration interval set by the light absorption coefficient calculation unit 310 (step S57: YES), light absorption is performed from the light absorption coefficient distribution of the dermis layer. A coefficient is acquired (step 58).

The light absorption coefficient acquisition unit 312 determines whether or not the light absorption coefficient having the number of wavelengths corresponding to the number of types of skin main components has been calculated (step S44).
Here, when it is determined that the light absorption coefficient acquisition unit 312 has not calculated the light absorption coefficient of the number of wavelengths corresponding to the number of types of the main components of the skin (step S44: NO), irradiation with short-time pulse light (step S44) Returning to S41), the light absorption coefficient of the number of wavelengths corresponding to the number of types of the main component of the skin that has not been calculated yet is calculated, and it is determined again whether or not the light absorption coefficient can be calculated (step S44).

  On the other hand, when it is determined that the light absorption coefficient acquisition unit 312 has calculated the light absorption coefficient of the number of wavelengths corresponding to the number of types of main components of the skin (step S44: YES), the concentration calculation unit 313 calculates the above equation (14 ) To calculate the concentration of glucose contained in the dermis layer (step S45).

Thus, according to the present embodiment, the absorption coefficients μ _{1 to} μ ₃ are calculated by the integrated value of the optical path length during the time τ. Thus, it is possible to reduce the influence on the calculation result of the absorption coefficient μ ₁ ~μ ₃ by the error contained in the measured received light intensity I (t).

[Sixth Embodiment]
FIG. 18 is a schematic block diagram showing a configuration of a blood sugar level measuring apparatus (concentration quantifying apparatus) according to the sixth embodiment of the present invention.
The blood glucose level measuring apparatus 400 of the present embodiment is different from the blood glucose level measuring apparatus 300 of the fourth embodiment in that the blood glucose level measuring apparatus 400 includes an irradiation unit 304, a light receiving unit 305, and a computer system 401. The computer system 401 includes a storage unit 402 and a control unit (CPU) 403. The storage unit 402 stores an optical path length distribution storage unit 302 and a time-resolved waveform storage unit that store simulation results in the simulation unit 301. 303, the control unit (CPU) 403 includes an optical path length acquisition unit 307, a non-absorption light intensity acquisition unit 308, a measurement light intensity acquisition unit 306, an integration interval calculation unit 309, a light absorption coefficient calculation unit 310, a light The point is that the functions of the absorption coefficient distribution storage unit 311, the light absorption coefficient acquisition unit 312 and the concentration calculation unit 313 are executed.

  Also in the blood sugar level measuring apparatus 400 of the present embodiment, the same actions and effects as the blood sugar level measuring apparatus 300 of the first embodiment can be achieved.

[Seventh Embodiment]
FIG. 19 is a schematic block diagram showing the configuration of a blood sugar level measuring apparatus (concentration quantifying apparatus) according to the seventh embodiment of the present invention. The blood sugar level measuring apparatus 500 of this embodiment is the blood sugar level of the fourth embodiment. The difference from the measuring apparatus 300 is that an absorption light intensity acquisition unit (light intensity model acquisition unit) 501 is provided between the time-resolved waveform storage unit 303 and the integration interval calculation unit 309 in parallel with the non-absorption light intensity acquisition unit 308. It is a point.

  The absorption-time light intensity acquisition unit 501 stores a model of the time-resolved waveform of the short-time pulsed light from the time-resolved waveform storage unit 303 that stores the absorption-time light intensity obtained similarly to the non-absorption-time light intensity obtained by the simulation unit 301. The light intensity upon absorption at a predetermined time is acquired. Here, the light intensity at the time of absorption at a certain time is acquired from the time-resolved waveform storage unit 303.

  The integration interval calculation unit 309 includes the optical path length of each skin layer of the model of the optical path length distribution acquired by the optical path length acquisition unit 307 and the time-resolved waveform of the short-time pulse light acquired by the non-absorption light intensity acquisition unit 308. The light intensity at the time of non-absorption of the model, the light intensity at the time of absorption of the model of the time-resolved waveform of the short-time pulse light acquired by the absorption light intensity acquisition unit 501, and the light intensity received by the light receiving unit 305 acquired by the measurement light intensity acquisition unit 306 Based on the distribution, an integration interval of a region corresponding to the light intensity of an arbitrary layer is calculated from the light intensity distribution.

When the blood glucose level is measured using the blood glucose level measuring apparatus 500, the light absorption coefficient of the dermis layer is calculated by changing the integration interval.
In this case, the integration interval calculation unit 309 performs (1) the minimum detection sensitivity from the time when the light intensity output from the light receiving unit 305 that receives the backscattered light exceeds the minimum detection sensitivity of the measurement light intensity acquisition unit 306. (2) the time characteristic of the non-absorbing light intensity acquired from the time-resolved waveform storage unit 303 storing the non-absorbing light intensity obtained by the simulation unit 301, (3) ) Time characteristics of absorption light intensity acquired from the time-resolved waveform storage unit 303 storing the absorption light intensity obtained by the simulation unit 301, (4) the interval between the light receiving unit 305 and the irradiation unit 304 in contact with the skin surface, 5) Using the size and optical characteristics (scattering coefficient, absorption coefficient, anisotropic parameter, or refractive index) of the skin model given to the simulation unit 301, the integration section It is calculated. More specifically, the start time, end time, and increment time of the integration interval are calculated.

  Based on the integration interval calculated by the integration interval calculation unit 309, the light absorption coefficient calculation unit 310 to the concentration calculation unit 313 calculate the concentration and concentration of glucose contained in the layer having the specific depth. Since it is completely the same as the blood glucose level measuring apparatus 300 of the fourth embodiment, the description thereof is omitted.

In the present embodiment, similarly to the fourth embodiment, the light from the dermis layer can be measured separately from the light from other layers, and the influence of the light from other layers on the light from the dermis layer can be measured. Can be reduced. Therefore, the glucose concentration in the dermis layer can be accurately measured, and as a result, the glucose concentration in the dermis layer can be quantified non-invasively and accurately.
Moreover, the measurement accuracy of the glucose concentration in the dermis layer can be increased by varying the integration interval.

As described above, each embodiment of the present invention has been described with reference to the drawings. However, the specific configuration is not limited to the above-described one, and various design changes and the like can be made without departing from the scope of the present invention. Is possible.
For example, in each of the above embodiments, the blood sugar level measuring device is used as the concentration determination device, the skin of a human palm is used as the observation target, glucose is used as the target component, and short-time pulsed light is used as the pulsed light. Although the case of measuring the concentration of glucose contained in the dermal layer of the present invention is not limited to this, the concentration determination method is not limited to this, and the concentration of the target component in an arbitrary layer to be observed formed from a plurality of light scattering medium layers May be used in other devices for quantitative determination, and short-time pulsed light with a specific wavelength may be replaced with continuous light with a specific wavelength.
For example, when it is applied to a portable skin main component concentration measuring apparatus, it can be effectively used for examination, diagnosis and treatment of skin diseases.

  DESCRIPTION OF SYMBOLS 300 ... Blood glucose level measuring apparatus (concentration determination apparatus), 302 ... Optical path length distribution storage part, 303 ... Time-resolved waveform storage part, 304 ... Irradiation part, 305 ... Light receiving part, 306 ... Measurement light intensity acquisition part (light intensity acquisition part) , 307 ... Optical path length acquisition unit, 308 ... Non-absorption light intensity acquisition unit (light intensity model acquisition unit), 309 ... Integration interval calculation unit, 310 ... Light absorption coefficient calculation unit, 311 ... Light absorption coefficient distribution storage unit, 312 DESCRIPTION OF SYMBOLS ... Light absorption coefficient acquisition part, 313 ... Concentration calculation part, 31 ... Skin (observation object), 33 ... Dermal layer (arbitrary layer), 400 ... Blood glucose level measuring device (concentration quantification device), 500 ... Blood glucose level measuring device ( Concentration quantification device), 501... Absorption light intensity acquisition unit (light intensity model acquisition unit), S21 to S25, S31 to S38, S41 to S45, S51 to S58.

Claims (10)

A concentration quantification device for quantifying the concentration of a target component in an arbitrary layer among observation targets composed of a plurality of layers,
An irradiation unit for irradiating light to the skin layer to be observed;
A light receiving unit that receives light scattered from the observation target by the light irradiation;
An optical path length acquisition unit for acquiring the optical path length of the skin layer;
A light intensity acquisition unit for acquiring the intensity of light received by the light receiving unit;
Based on the light intensity distribution of the received light intensity acquired by the light intensity acquisition unit and the optical path length of the skin layer acquired by the optical path length acquisition unit, the light intensity of the skin layer from the light intensity distribution An integration interval calculation unit that calculates an integration interval that is a time range of an area corresponding to the distribution ;
A light absorption coefficient calculating unit that calculates the light absorption coefficient of a biological component in the skin layer by changing the integration interval;
A concentration calculator that calculates the concentration of the target component based on the light absorption coefficient of the biological component and the pre-stored estimated error rate of the skin layer;
A concentration quantification apparatus comprising: The light absorption coefficient calculator is
A light absorption coefficient calculation unit that calculates a light absorption coefficient of the arbitrary layer based on the integration interval calculated by the integration interval calculation unit;
A light absorption coefficient distribution storage unit that calculates and stores a light absorption coefficient distribution in the integration interval based on the light absorption coefficient of the arbitrary layer calculated by the light absorption coefficient calculation unit;
A light absorption coefficient acquisition unit that acquires the light absorption coefficient of the target component in the arbitrary layer based on the light absorption coefficient distribution acquired by the light absorption coefficient distribution storage unit. 1. The concentration determination apparatus according to 1. The light is short-time pulsed light,
The light intensity acquisition unit acquires light intensities at a plurality of times t _{1 to} t _{m that} are equal to or greater than the number n of the observation target layers in the integration interval (where n is a natural number of 1 or more, and m is n More natural numbers),
The light absorption coefficient calculator is
Ln (·) indicating the natural logarithm, I (t) indicating the light intensity received by the light receiving unit at the time t within the integration interval, and the time within the integration interval of the time-resolved waveform model of the short-time pulsed light N (t) indicating the light intensity at t, Li (t) indicating the optical path length of the i-th layer at time t within the integration interval of the model of the optical path length distribution of the skin layer, and the light absorption coefficient of the i-th layer Using μ _i shown,

Calculate the light absorption coefficient of any layer from
The concentration determination apparatus according to claim 2, wherein:   The concentration quantification apparatus according to claim 3, wherein the plurality of times at which the light intensity acquisition unit acquires the light intensity includes a peak time of an optical path length distribution of each of the plurality of layers. The light is short-time pulsed light,
The light intensity acquisition unit acquires the light intensity at least for a predetermined time τ from a predetermined time in the integration interval,
The light absorption coefficient calculator is
Ln (·) indicating the natural logarithm, I (t) indicating the light intensity received by the light receiving unit at the time t within the integration interval, and the time within the integration interval of the time-resolved waveform model of the short-time pulsed light N (t) indicating the light intensity at t, Li (t) indicating the optical path length of the i-th layer at time t within the integration interval of the model of the optical path length distribution of the skin layer, and the number of layers to be observed N shown, and μ i indicating the light absorption coefficient of the i-th layer,

Calculate the light absorption coefficient of any layer from
The concentration determination apparatus according to claim 2, wherein: The irradiation unit irradiates light having a plurality of wavelengths 1 to q,
The light absorption coefficient calculation unit calculates a light absorption coefficient in the arbitrary layer for each of a plurality of wavelengths irradiated by the irradiation unit,
The concentration calculator
Μa (i) indicating the light absorption coefficient of the wavelength i in the a-layer which is the arbitrary layer, gj indicating the molar concentration of the j-th component forming the observation target, and the light absorption coefficient of the j-th component relative to the wavelength i. Εj (i), p indicating the number of main components forming the observation object, q indicating the number of types of wavelengths irradiated by the irradiation unit,

Calculate the concentration of the target component in the arbitrary layer from
The concentration determination apparatus according to any one of claims 2 to 5, wherein   The concentration quantification apparatus according to claim 6, wherein the plurality of lights irradiated by the irradiation unit includes light having a wavelength that increases a light absorption coefficient of the target component.   The concentration determination according to claim 6, wherein the plurality of lights emitted by the irradiation unit include light having a wavelength at which the orthogonality of the absorption spectrum distribution of each of the main components constituting the observation target is increased. apparatus. A concentration quantification device comprising an irradiating unit for irradiating light to the skin layer and a light receiving unit for receiving light scattered from the skin layer by the irradiation of the light, and quantifying the concentration of biological components in the skin layer was used A concentration determination method,
By the irradiation unit, the skin layer is irradiated with the light,
The light receiving unit receives light scattered from the skin layer by the light irradiation,
The light intensity acquisition unit acquires the intensity of the light received by the light receiving unit at a predetermined time after the time when the irradiation unit irradiated the light,
The optical path length acquisition unit acquires the optical path length of the skin layer,
Based on the light intensity distribution of the intensity of the received light acquired by the light intensity acquisition unit and the optical path length of the skin layer acquired by the optical path length acquisition unit by the integration interval calculation unit, the light of the skin layer Calculate the integration interval, which is the time range of the region corresponding to the intensity distribution,
The light absorption coefficient calculation unit calculates the light absorption coefficient of the biological component in the skin layer by changing the integration interval,
The concentration calculation unit calculates the concentration of the biological component based on the light absorption coefficient of the biological component and the pre-stored estimated error rate of the skin layer.
Concentration determination method characterized by this. A computer for a concentration quantification apparatus comprising: an irradiating unit that irradiates light to a skin layer; and a light receiving unit that receives light scattered from the skin layer by irradiation of the light, and quantifies a concentration of a biological component in the skin layer. ,
An irradiation procedure for irradiating the skin layer with the light;
A light receiving procedure for receiving light scattered from the skin layer by the light irradiation;
A light intensity acquisition procedure for acquiring the intensity of light received at a predetermined time after the light irradiation time;
An optical path length acquisition procedure for acquiring the optical path length of the skin layer;
Corresponds to the light intensity distribution of the skin layer based on the light intensity distribution of the received light intensity acquired by the light intensity acquisition procedure and the optical path length of the skin layer acquired by the optical path length acquisition unit. Integration interval calculation procedure for calculating the integration interval that is the time range of the region,
A light absorption coefficient calculation procedure for calculating a light absorption coefficient of a biological component in the skin layer by changing the integration section calculated by the integration section calculation procedure;
A concentration calculation procedure for calculating the concentration of the biological component based on the light absorption coefficient of the biological component and the pre-stored estimated error rate of the skin layer;
A program characterized by having executed.

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