JP5477058B2 - Component measuring device - Google Patents

Description

  The present invention relates to a component measuring apparatus, and more particularly to an improvement of a component measuring apparatus that measures the concentration of a component with laser light.

  Conventionally, for example, when measuring the concentration of blood sugar or other components in blood, blood is collected from a human body with a syringe or punctured with a fingertip or earlobe, and blood is actually collected to obtain blood. Often the concentration of glucose in the medium.

  In general, blood glucose levels vary greatly depending on measurement conditions such as before and after meals and after exercise. Therefore, blood glucose levels must be measured frequently in order to obtain accurate blood glucose level data. The conventional method has a problem that the pain given to the subject is great.

  Therefore, the applicant does not invade the living body and collect blood, but irradiates the living body with laser light to detect reflected light from the living body, and the degree to which the laser light is absorbed by the living body (absorbance). ), A biological component measuring apparatus using a confocal optical system that measures the concentration of a target component (for example, glucose in blood) has been filed (see Patent Document 1).

FIG. 6 is a configuration diagram of the biological component measuring apparatus described in Patent Document 1.
In FIG. 6, the laser light output from the laser diode 1 is shaped into parallel light by the collimating lens 2, and is applied to the half mirror 3 disposed in a state having an inclination of approximately 45 ° with respect to the optical axis of the collimating lens 2. Incident. As the laser diode 1, for example, a variable wavelength laser that can output laser light in a wavelength region of 1600 nm to 1700 nm that is relatively large in glucose absorption is used.

  The parallel light transmitted through the half mirror 3 is condensed by the objective lens 4 and irradiated to the internal tissue of the living body LB. The laser light reflected by the internal tissue of the living body LB is again incident on the objective lens 4 and shaped into parallel light, and is incident on the half mirror 3 and is subjected to optical path conversion so as to be reflected in a direction of approximately 90 °.

  The laser light reflected by the optical path change by the half mirror 3 is condensed by the lens 5 and incident on the pinhole 6. The laser light that has passed through the pinhole 6 enters the light receiving element 7 and is converted into an electrical signal. Here, the laser diode 1, the objective lens 4, the pinhole 6 and the light receiving element 7 constitute a confocal optical system.

  The light receiving element 7 converts it into an electric signal whose intensity and size increase or decrease in accordance with the amount of received laser light, and inputs it to the A / D converter 8. The A / D converter 8 converts the electrical signal input from the light receiving element 7 into digital data and inputs the digital data to the data analysis unit 9.

  The data analysis unit 9 performs quantitative analysis of the components of the living body LB based on a plurality of electrical signals converted and output from the light receiving element 7 when each of the two or more laser beams having different wavelengths is irradiated onto the living body LB.

  Specifically, when quantifying the blood sugar level, that is, the glucose concentration in the blood, the data analysis unit 9 stores a calibration curve between the glucose concentration in the blood measured in advance and the absorbance of the laser beam, and the data The analysis unit 9 quantifies the glucose concentration in the blood of the living body LB based on the calibration curve.

JP 2008-301944 A

  However, such a conventional biological component measuring apparatus forms a predetermined spatial light path designed in advance so as to be in an optimum optical condition when attaching various optical components constituting the irradiation system and the light receiving system of the apparatus. Since they must be arranged in a positional relationship and the degree of freedom during assembly and adjustment work is limited, there are problems that work efficiency is reduced and miniaturization is difficult to achieve.

  The present invention solves such problems, and an object of the present invention is to realize a component measuring apparatus that has a high degree of freedom in assembling and adjusting various optical components and can be easily miniaturized.

In order to achieve such a problem, the invention according to claim 1 of the present invention is:
A laser output light is applied to the internal tissue of the measurement target via a confocal optical system including an objective lens, and the reflected light reflected by the internal tissue of the measurement target is detected via the confocal optical system . In the component measuring apparatus having a data analysis unit that measures the component to be measured based on the data output from the light receiving element of
The laser comprising a wavelength tunable light source;
The first light receiving element provided so that at least the light receiver in the central region and the light receiver in the outer peripheral region are electrically separated;
A movement drive mechanism for moving the confocal optical system and the measurement object relatively three-dimensionally;
An optical fiber for irradiating the measurement target surface with the output light of the laser;
A second light receiving element for detecting reflected light on the surface of the measurement object based on irradiation of the optical fiber;
A laser driving circuit for driving the laser so that the output light intensity of the laser is maintained at a predetermined value based on a detection signal of the second light receiving element;
At least one end of the optical fiber is provided with a gradient index lens,
The data analysis unit divides the detection signal of the first light receiving element that detects the reflected light reflected by the internal tissue of the measurement target by the detection signal of the second light receiving element through the confocal optical system. The variation due to the surface reflection of the measurement object is compensated by measuring the component of the measurement object based on the normalized data .

Claim 2 is the component measuring apparatus according to claim 1,
Using a built-in third light receiving element for monitoring the output light as the laser,
The data analysis unit
A first normalized signal obtained by dividing the detection signal of the light receiving element that detects the reflected light reflected by the internal tissue of the measurement target by the detection signal of the second light receiving element through the confocal optical system; A second normalized signal obtained by dividing the detection signal of the light receiving element that detects the reflected light reflected by the internal tissue of the measurement target by the detection signal of the third light receiving element through the confocal optical system is linear. The component to be measured is measured based on the combined data .

  With this configuration, the mounting position of each optical component can be changed relatively freely, and the entire component measuring apparatus can be downsized.

It is a block diagram which shows one Example of this invention. It is a block diagram which shows the other Example of this invention. It is a block diagram which shows the other Example of this invention. It is a block diagram which shows the other Example of this invention. It is a block diagram which shows the other Example of this invention. It is a block diagram which shows an example of the conventional biological component measuring apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, and the same reference numerals are given to portions common to FIG. The difference between the apparatus of FIG. 1 and the apparatus of FIG. 6 is that in the apparatus of FIG. 1, the spatial optical path other than the periphery of the half mirror 3 is replaced with an optical fiber.

  In FIG. 1, laser light emitted from a laser diode 1 is incident on a gradient index lens 10, and is coupled and incident on one end of an optical fiber 11 via the gradient index lens 10.

  The parallel light transmitted through the optical fiber 11 is incident on the gradient index lens 12 connected to the other end of the fiber 11, once converted into condensed light, then shaped again into parallel light and incident on the half mirror 3. Is done.

  The parallel light that has passed through the half mirror 3 is incident on the gradient index lens 13, once converted into condensed light, shaped again into parallel light, and incident on one end of the optical fiber 14.

  The parallel light transmitted through the optical fiber 14 is incident on the gradient index lens 15 connected to the other end of the fiber 14, once converted into condensed light, then shaped again into parallel light and incident on the objective lens 4. Is done.

  The objective lens 4 collects parallel light and irradiates the internal tissue of the living body LB. The parallel light reflected by the internal tissue of the living body LB is again incident on the objective lens 4 and shaped into parallel light, and again through the optical path of the gradient index lens 15 → the optical fiber 14 → the gradient index lens 13. The light path is changed so as to be incident on the half mirror 3 and reflected in a direction of approximately 90 °.

  The parallel light that has been subjected to optical path conversion by the half mirror 3 and reflected is incident on the gradient index lens 16 to be condensed and incident on the pinhole 6. The condensed light that has passed through the pinhole 6 is incident on one end of the optical fiber 17.

  The parallel light transmitted through the optical fiber 17 is incident on a gradient index lens 18 connected to the other end of the fiber 17, once converted into parallel light, shaped again into condensed light, and incident on the light receiving element 7. And converted into an electrical signal.

  The light receiving element 7 converts the received light into an electrical signal whose intensity and size increase or decrease in accordance with the amount of received laser focused light, and inputs the electrical signal to the A / D converter 8. The A / D converter 8 converts the electrical signal input from the light receiving element 7 into digital data and inputs the digital data to the data analysis unit 9. Here, the laser diode 1, the objective lens 4, the pinhole 6 and the light receiving element 7 constitute a confocal optical system.

  As in the conventional case, the data analysis unit 9 uses the plurality of electrical signals converted and output from the light receiving element 7 when each of the two or more laser beams having different wavelengths is irradiated on the living body LB. Perform quantitative analysis.

  In such a configuration, paying attention to the optical path of the apparatus, only the peripheral part of the half mirror 3 is configured by a spatial optical path, and most of the other is configured by an optical fiber. Therefore, the laser diode 1 and the objective lens constituting the apparatus 4. The mounting position of each optical component such as the light receiving element 7 with respect to the half mirror 3 can be changed relatively freely, and the design freedom of the structural position is maintained.

  As a result, the degree of freedom in assembling and adjusting various optical components is increased, and the mounting positions of the optical components such as the laser diode 1, the objective lens 4, and the light receiving element 7 with respect to the half mirror 3 in the housing of the apparatus are appropriately selected. By doing so, the mounting density of apparatus component parts can be increased, and the whole component measuring apparatus can be miniaturized.

  In the above embodiment, stable measurement can be performed by driving the laser diode 1 with an automatic output control loop so as to maintain the light intensity irradiated from the laser diode 1 to the measurement target at a predetermined value.

FIG. 2 is a block diagram showing an example in which such a configuration is applied to the embodiment of FIG. In the embodiment of FIG. 2, a part of the output light of the laser diode 1 is irradiated onto the surface of the living body LB to be measured via the optical fiber 19 and the reflected light is detected by the second light receiving element 20. The output signal of the second light receiving element 20 is given to the laser diode drive circuit 21 to drive the output light intensity of the laser diode 1 so as to maintain a predetermined value.

  Thereby, the output light intensity change resulting from the temperature change and spatial intensity fluctuation of the laser diode 1 can be suppressed, and a stable component measurement result can be obtained.

  Further, the output signal of the second light receiving element 20 is added to the data analysis unit 9 via the A / D converter 22, and the output signal of the first light receiving element 7 is divided by the output signal of the second light receiving element 20. By normalizing, the output fluctuation of the laser diode 1 and the fluctuation due to the surface reflection of the measurement target LB can be compensated.

  FIG. 3 is a block diagram showing an embodiment in which the laser diode 1 shown in FIG. 2 is incorporated with a third light receiving element (not shown) for monitoring the output light. The output signal of the third light receiving element is also input to the laser diode drive circuit 21 and is driven so as to maintain the output light intensity of the laser diode 1 at a predetermined value.

  The output signal of the third light receiving element is also input to the data analyzing unit 9 via the A / D converter 23, and the output signal of the first light receiving element 7 is divided by the output signal of the third light receiving element. Standardize. As a result, the data analysis unit 9 linearly combines the two normalized signals to obtain a coupling coefficient by multivariate analysis, and based on these values, the output fluctuation of the laser diode 1 and the fluctuation due to the surface reflection of the measurement target LB. Is compensated with high accuracy.

  FIG. 4 shows a half mirror 23 disposed in the optical path between the gradient index lens 15 and the objective lens 4 in the embodiment of FIG. A fourth light receiving element 24 for detecting light and an A / D converter 25 for converting an output signal of the fourth light receiving element 24 into a digital signal are added.

  With this configuration, the fourth light receiving element 24 detects the amount of spatial variation in the output light of the laser diode 1 in the optical path to the half mirror 23. The output signal of the fourth light receiving element 24 is also input to the laser diode drive circuit 21 and is driven so as to maintain the output light intensity of the laser diode 1 at a predetermined value.

  The output signal of the fourth light receiving element 24 is also input to the data analysis unit 9 via the A / D converter 25, and the output signal of the first light receiving element 7 is divided by the output signal of the fourth light receiving element 24. And standardize. As a result, the data analysis unit 9 linearly combines the three standardized signals to obtain a coupling coefficient by multivariate analysis, and based on these values, the output variation and spatial variation of the laser diode 1 and the surface of the measurement target LB Compensates for fluctuations due to reflection more accurately.

  FIG. 5 is obtained by omitting the signal system including the optical fiber 19, the second light receiving element 20, and the A / D converter 22 from the embodiment of FIG. According to the configuration of FIG. 5, the laser diode driving circuit 21 is driven so as to maintain the output light intensity of the laser diode 1 at a predetermined value based on the output signals of the third light receiving element and the fourth light receiving element 24. To do. Then, the data analysis unit 9 outputs the normalized signal obtained by dividing the output signal of the first light receiving element 7 by the output signal of the third light receiving element and the output signal of the first light receiving element 7 to the output of the fourth light receiving element 24. Based on the normalized signal divided by the signal, the output fluctuation and spatial fluctuation of the laser diode 1 are compensated with high accuracy.

  In the above-described embodiment, an example in which the optical paths of the laser diode 1, the objective lens 4, and the light receiving element 7 are configured by optical fibers has been described. However, in these optical paths, a portion that contributes greatly to miniaturization or a spatial optical path. Only a part of the optical path portion that is structurally unstable may be selectively configured with an optical fiber.

  Moreover, although the example which uses a variable wavelength laser as a light source was demonstrated in the said Example, when a measurement component is specified, a single wavelength laser may be sufficient.

  Moreover, although the example which measures the blood glucose level in the blood of a human body was demonstrated in the said Example, it is effective also for the quantitative measurement of blood components other than a blood glucose level, or a tissue fluid component.

  In addition, the measurement target is not limited to the human body, and is effective for quantitative measurement of internal substances such as animals and plants.

  In addition, the measurement target is not limited to a living body, but is also effective for nondestructive inspection of structures and compositions of agricultural products, marine products, food, organic materials, and quantitative measurement of chemical substances.

  As described above, according to the present invention, it is possible to realize a component measuring apparatus that has a high degree of freedom during assembly and adjustment of various optical components and can be easily miniaturized, including blood sugar levels in human blood. It is suitable for various component measurements.

DESCRIPTION OF SYMBOLS 1 Laser diode 3, 23 Half mirror 4 Objective lens 6 Pinhole 7, 20, 24 Light receiving element 8, 22, 23, 25 A / D converter 9 Data analysis part 10, 12, 13, 15, 16, 18 Refractive index Distributed lens 11, 14, 17, 19 Optical fiber

Claims (2)

A laser output light is applied to the internal tissue of the measurement target via a confocal optical system including an objective lens, and the reflected light reflected by the internal tissue of the measurement target is detected via the confocal optical system. In the component measuring apparatus having a data analysis unit that measures the component to be measured based on the data output from the light receiving element of
The laser comprising a wavelength tunable light source;
The first light receiving element provided so that at least the light receiver in the central region and the light receiver in the outer peripheral region are electrically separated;
A movement drive mechanism for moving the confocal optical system and the measurement object relatively three-dimensionally;
An optical fiber for irradiating the measurement target surface with the output light of the laser;
A second light receiving element for detecting reflected light on the surface of the measurement object based on irradiation of the optical fiber;
A laser driving circuit for driving the laser so that the output light intensity of the laser is maintained at a predetermined value based on a detection signal of the second light receiving element;
At least one end of the optical fiber is provided with a gradient index lens,
The data analysis unit divides the detection signal of the first light receiving element that detects the reflected light reflected by the internal tissue of the measurement target by the detection signal of the second light receiving element through the confocal optical system. Then, the component measurement apparatus compensates for the variation due to the surface reflection of the measurement object by measuring the component of the measurement object based on the normalized data. Using a built-in third light receiving element for monitoring the output light as the laser,
The data analysis unit
A first normalized signal obtained by dividing the detection signal of the light receiving element that detects the reflected light reflected by the internal tissue of the measurement target by the detection signal of the second light receiving element through the confocal optical system; A second normalized signal obtained by dividing the detection signal of the light receiving element that detects the reflected light reflected by the internal tissue of the measurement target by the detection signal of the third light receiving element through the confocal optical system is linear. The component measuring apparatus according to claim 1 , wherein the component to be measured is measured based on the combined data .

Images