JP2014160175A - Linear polarization purity improving unit, linear polarization purity improving device, optical measurement device and medical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a new method for improving the purity of linear polarization.SOLUTION: A linear polarization purity improving unit 1A comprises a circular polarization section 40, and a linear polarization section 50 that converts outgoing light from the circular polarization section 40 into linear polarization. The linear polarization purity improving unit 1A causes the linear polarization made incident upon the circular polarization section 40 to be ejected from the linear polarization section as linear polarization with higher linear polarization purity than the incident light.

Description

  The present invention relates to an apparatus for improving the purity of linearly polarized light.

  By measuring the light that has passed through the substance, the components of the substance can be known without touching the substance directly. For example, when the optical rotation is examined, the concentration of a predetermined component contained in the measurement object can be estimated. Optical rotation refers to the property of rotating the plane of polarization when linearly polarized light passes through an optically active substance such as glucose.

  As a technique using this optical rotatory power, for example, Patent Document 1 discloses that transmitted light in which linearly polarized light is transmitted through a measurement object is orthogonally separated by a polarization beam splitter, and each of the orthogonally separated polarized light components is separated by two light receiving elements. A technique for receiving light and measuring the optical rotation based on the difference between the received light levels is disclosed.

International Publication No. 99/30132

  In the conventional technique represented by Patent Document 1, it is assumed that the linearly polarized light incident on the measurement target is completely linearly polarized light. However, in general, the polarization state of light emitted from a light source (hereinafter referred to as “light source light”) always fluctuates. For example, the angle formed by the polarization plane of the light source light always vibrates slightly. For this reason, depending on the optical element having the polarization characteristics, the transmittance and the reflectance vary due to the variation of the polarization state of the light source light, and the polarization purity is reduced.

  Here, the polarization purity is the ratio between the linearly polarized light component and the non-linearly polarized light component in the case of linearly polarized light. In order to perform high-accuracy measurement, measurement is performed using linearly polarized light with high polarization purity. Is needed. Therefore, when an optical element having a polarization purity not exceeding a certain level is used, a measurement error may occur due to the optical element itself.

  In order to prevent this, an optical element whose characteristics hardly depend on or hardly changes the polarization state of the light source light, or a light source that hardly changes or hardly changes the polarization state is used. There is a need. However, none of them are ideal, and the polarization state may fluctuate slightly. Therefore, it is convenient if the polarization purity can be improved.

  The present invention has been made in view of the above-described problems, and an object thereof is to propose a new technique for improving the purity of linearly polarized light.

  A first invention for solving the above-described problems includes a circularly polarized light portion and a linearly polarized light portion that linearly polarizes light emitted from the circularly polarized light portion, and is linearly polarized light incident on the circularly polarized light portion. Is a linearly polarized light purity improver that emits from the linearly polarized light section with linearly polarized light having a higher linearly polarized purity than the incident light.

  According to the first aspect of the invention, the linearly polarized light incident on the circularly polarizing part is circularly polarized by the circularly polarizing part. And the emitted light from a circularly-polarizing part is linearly polarized by the linearly-polarizing part. Incident light is converted into isotropic circularly polarized light having a constant electric field intensity by the circularly polarizing portion. For this reason, even if there is a fluctuation in the original linearly polarized light, the output light from the circularly polarized light part is linearly polarized by the linearly polarized light part. Can be obtained.

  Further, as a second invention, the linear polarization purity improver of the first invention further includes a front-stage linear polarization section provided in a front stage of the circular polarization section that linearly polarizes light incident on the circular polarization section. The circularly polarized light part has a quarter wave plate, and the angle formed by the optical axis direction of the preceding linearly polarized light part and the optical axis direction of the quarter wave plate is 45 °. It is good also as comprising a purity improver.

  According to the second aspect of the invention, the light incident on the circularly polarized light portion is linearly polarized by the linearly polarized light portion provided in the previous stage of the circularly polarized light portion. Here, the circularly polarizing part has a quarter-wave plate. In order to appropriately convert linearly polarized light into circularly polarized light by the quarter wave plate, it is necessary to determine the angle of the circularly polarized light portion so that the fast axis component and the slow axis component of the light incident on the circularly polarized light portion are equal. is there. Therefore, in the second aspect of the invention, the angle formed by the optical axis direction of the front-stage linearly polarizing portion and the optical axis direction of the quarter-wave plate is set to 45 °. As a result, the linearly polarized light is appropriately circularly polarized in the circular polarization portion.

  Further, as a third invention, the circularly polarizing section in the linear polarization purity improver of the first or second invention has a plurality of types of quarter-wave plates that can be replaced according to the wavelength of incident light, and is a straight line. A polarization purity improver may be configured.

  According to the third aspect of the invention, the circular polarization unit in the linear polarization purity improver has a plurality of types of quarter-wave plates that can be replaced according to the wavelength of incident light. In general, a quarter wave plate has wavelength dependency. For this reason, by making it possible to replace a plurality of types of quarter-wave plates according to the wavelength of incident light, it is possible to obtain high-purity linearly polarized light that matches the wavelength of incident light.

  In addition, as a fourth invention, a linear polarization purity improving apparatus including a plurality of linear polarization purity improvers according to the first invention may be configured.

  In general, the linearly polarizing section has a property of transmitting light slightly in the axial direction other than the transmission axis direction. However, as in the fourth aspect of the invention, a linear polarization purity improving apparatus including a plurality of linear polarization purity improvers is configured, and by repeating circular polarization and linear polarization, axial directions other than the transmission axis direction Accordingly, it is possible to reduce the amount of transmitted light in a stepwise manner and to obtain linearly polarized light with higher purity.

  In addition, as a fifth invention, the linear polarization purity improver of the first invention is provided in a plurality of stages, and the circular polarization portion of the linear polarization purity improver of the first stage is provided in the front stage of the linear polarization purity improver of the first stage. It is good also as comprising the linear polarization | polarized-light purity improvement apparatus further equipped with the front | former stage linearly-polarized-light part which makes incident light linearly polarized light.

  According to the fifth aspect of the invention, not only the linear polarization purity improvers are provided in a plurality of stages, but also enter the circular polarization portion of the first stage linear polarization purity improver before the first stage linear polarization purity improver. By providing a linearly polarizing portion that linearly polarizes light, it becomes possible to obtain linearly polarized light with even higher purity.

  Further, as a sixth invention, in the linear polarization purity improving apparatus according to the fourth or fifth invention, the circularly polarized light portion of the linear polarization purity improver at each stage has a quarter wavelength plate, and the circularly polarized light A linear polarization purity improving apparatus may be configured in which an angle formed by the optical axis direction of the linearly polarizing unit located immediately before the optical axis direction and the optical axis direction of the ¼ wavelength plate is 45 °.

  According to the sixth aspect of the invention, the circular polarization unit of each stage of the linear polarization purity improver has the quarter wavelength plate, the optical axis direction of the linear polarization unit located immediately before the circular polarization unit, and the The angle formed with the optical axis direction of the quarter-wave plate is 45 °. Thereby, in the circular polarization part of each linearly polarized light purity improver, it becomes possible to appropriately circularly polarize the incident linearly polarized light by the quarter wavelength plate.

  Further, as a seventh invention, the linear polarization purity improver of any one of the first to third inventions, or the linear polarization purity improver of any of the fourth to sixth inventions (hereinafter collectively referred to as “ A linear polarization purity improver "), an optical measurement device that transmits the light emitted from the linear polarization purity improver to the measurement object and measures the optical rotation of the measurement object based on the transmitted light. It is good also as comprising.

  According to the seventh aspect of the invention, there is provided an optical measurement device that transmits the light emitted from the linear polarization purity improver of the above invention to the measurement target and measures the optical rotation of the measurement target based on the transmitted light. Can be configured. Since the highly purified linearly polarized light can be obtained by using the linearly polarized light purity improver of the present invention, the optical rotation of the measurement object can be measured with high accuracy by using the emitted light. .

  Further, as an eighth invention, the measurement object is measured by the optical measurement device according to the seventh invention that measures the optical rotation as a predetermined part having the permeability of the living body or a body fluid of the living body, and the optical measurement device. It is good also as comprising the medical device provided with the component concentration calculation part which measures the component concentration of a predetermined substance using an optical rotation.

  According to the eighth aspect of the invention, the optical rotation is measured using the measurement object as a predetermined part having permeability of the living body or a body fluid of the living body. Then, the component concentration of the predetermined substance is calculated using the measured optical rotation. This makes it possible to correctly measure the component concentration of the predetermined substance contained in the living body or body fluid.

The figure which shows the example of 1 structure of a linearly polarized light purity improver. The figure which shows the other structural example of a linearly polarized light purity improver. (1) Explanatory drawing of the polarization state of incident light. (2) Explanatory drawing when incident light is linearly polarized. (1) The figure which shows the polarization state of incident light. (2) Explanatory drawing when incident light is circularly polarized. (3) Explanatory drawing when circularly polarized light is linearly polarized. (1) The figure which shows the structural example of a blood glucose level measuring apparatus. (2) The figure which shows the structural example of an optical apparatus. The figure which shows the example of 1 structure of a linearly polarized light purity improvement apparatus. The figure which shows the other structural example of a linearly polarized light purity improvement apparatus. The figure which shows the structural example of the light source in a modification.

  Hereinafter, an example of a preferred embodiment of the present invention will be described with reference to the drawings. However, it goes without saying that embodiments to which the present invention can be applied are not limited to the embodiments described below.

1. 1st Embodiment FIG. 1: is a figure which shows the structure of 1 A of linear polarization purity improvers in 1st Embodiment. The linear polarization purity improver 1 </ b> A includes a circular polarization unit 40 and a linear polarization unit 50.

  The circular polarization unit 40 is a polarization element that circularly polarizes incident light, and is configured to include a quarter wavelength plate. The quarter-wave plate is a birefringent element that is constituted by, for example, a quartz wavelength plate and gives a phase difference of ¼ wavelength (= π / 2) between orthogonal polarization components of incident light. Sometimes referred to as a phase plate (retardation plate).

  The linear polarization unit 50 is a polarization element that linearly polarizes the light emitted from the circular polarization unit 40, and includes a linear polarizer. As the linear polarizer, for example, a polarizing optical element such as a calcite prism having birefringence such as a Gran type Thomson prism can be used.

  In order to appropriately convert linearly polarized light into circularly polarized light by the quarter wavelength plate, the angle of the circularly polarizing unit 40 is determined so that the fast axis component and the slow axis component of the light incident on the circularly polarizing unit 40 are equal. There is a need. This can be realized by inclining the polarization direction of the linearly polarized light incident on the circularly polarizing unit 40 by 45 ° with respect to the fast axis or the slow axis of the quarter-wave plate.

  3 and 4 are explanatory diagrams of the principle of improving the purity of linearly polarized light using the linearly polarized light purity improver 1A. In each of these drawings, the Z axis indicates an axis in the light traveling direction, and the X axis and the Y axis indicate axes orthogonal to the Z axis. The Z-axis is shown as an axis perpendicular to the paper surface, the X-axis is shown as a left-right axis toward the paper surface, and the Y-axis is shown as an up-down axis toward the paper surface. In FIGS. 3 and 4, some graphs are exaggerated to help understanding.

FIG. 3 is an explanatory diagram in the case of generating linearly polarized light using a conventional method. Here, a case where light source light emitted from a predetermined light source (for example, a semiconductor laser) is incident on a linear polarizer and converted into linearly polarized light is illustrated. The light source light will be described as elliptically polarized light that is close to linearly polarized light.
The light source light is elliptically polarized light, but when the tip of the electric field vector is projected onto the XY plane, it changes so as to draw an ellipse with the Z axis as the center. The problem is that the light source light has a slight fluctuation, and the tip of the ellipse vibrates slightly.

  FIG. 3 (2) shows a change in polarization state when the light source light of FIG. 3 (1) is incident on the linear polarizer. The light source light is elliptically polarized light, and its polarization state is indicated by a one-dot chain line. Further, in order to express the intensity of the electric field of the light source light (hereinafter referred to as “electric field intensity”), an electric field vector is drawn with a dashed line in the major axis direction of the ellipse for convenience. The length of the electric field vector is the electric field strength, which will be described as “E”. Further, the angle formed by the X axis and the electric field vector (the angle formed by the polarization plane of the light source light) will be described as a “deflection angle”.

  The linear polarizer has one transmission axis with respect to the traveling direction of light, and linearly polarized light is generated by passing polarized light through this transmission axis. However, light is actually transmitted slightly in directions other than the transmission axis direction. The light transmitted in a direction other than the transmission axis direction is referred to as “leakage light”. The leakage light is minimized with respect to the direction of an axis orthogonal to the transmission axis of the linear polarizer (hereinafter referred to as “transmission orthogonal axis”). The ratio between the polarization component in the transmission axis direction and the polarization component in the transmission orthogonal axis direction is called “extinction ratio”, and this extinction ratio represents the performance of the linear polarizer.

  As shown in FIG. 3 (2), the light source light, which is elliptically polarized with an electric field intensity E, has a polarization direction inclined by an angle Δθ with reference to the transmission axis of a linear polarizer inclined by an angle φ from the XY axis. Consider the case of transmission. As described with reference to FIG. 3A, minute fluctuations are generated in the light source light, and the deflection angle of the light source light represented by elliptically polarized light fluctuates. Therefore, the angle Δθ based on the transmission axis when the light source light is incident on the linear polarizer changes depending on the variation of the deflection angle of the light source light.

In this case, the electric field strength in the transmission axis direction of the transmitted light that passes through the linear polarizer is expressed as “E · cos Δθ”, and the electric field strength in the transmission orthogonal axis direction is expressed as “E · sin Δθ”. When this transmitted light is orthogonally separated along the XY axis, the X component and the Y component of the electric field vector can be expressed by the following equations (1) and (2), respectively.

At this time, when the azimuth angle χ of linearly polarized light is calculated using the X component and Y component of the electric field vector, the following equation (3) is obtained.

  From Equation (3), it can be seen that the azimuth angle χ of linearly polarized light depends on the angle Δθ. As described above, since the angle Δθ changes depending on the fluctuation of the light source light, it can be seen that the azimuth angle χ also changes depending on the fluctuation of the light source light. When the optical property (for example, optical rotation) of the measurement object is measured using such linearly polarized light, the measurement accuracy is lowered.

  FIG. 4 is an explanatory diagram when linearly polarized light is generated using the linearly polarized light purity improver 1A of FIG. FIG. 4A shows the polarization state of the light source light incident on the circular polarization unit 40, which is expressed by elliptically polarized light as in FIG.

  The light source light that is elliptically polarized light is circularly polarized by the circular polarization unit 40. Since the circular polarization unit 40 has a quarter wavelength plate, the phase of one of the orthogonal components of the light source light is advanced (or delayed) by a quarter wavelength. The light source light (ideally, linearly polarized light) incident on the circular polarization unit 40 can be regarded as a combination of left and right circularly polarized light. At this time, the deflection angle of the light source light is the phase difference between the left and right circularly polarized light. For this reason, when the phase difference of the left and right circularly polarized light varies, the deflection angle of the light source light also varies. However, circularly polarized light is either left-right polarized light. Therefore, even if the phase of the circularly polarized light is changed by circularly polarizing the light source light by the circularly polarizing unit 40, the electric field fluctuation having azimuth does not occur in the plane orthogonal to the traveling direction of the light. Accordingly, the light source light is converted into circularly polarized light having an isotropic electric field intensity “α · E” by passing through the circularly polarizing portion 40 (where 0 ≦ α ≦ 1).

  Next, the outgoing light from the circular polarization unit 40 enters the linear polarization unit 50. At this time, let us consider a case where the light emitted from the circularly polarizing unit 40 is transmitted with a displacement of the angle Δθ with reference to the transmission axis of the linearly polarizing unit 50 inclined by the angle φ from the XY axis. At this time, as described above, the change in the phase difference of the left and right circularly polarized light, which was the cause of the change in the deflection angle in the light source light, results in the change in the phase of either the left or right circularly polarized light due to circular polarization, In polarization, the concept of deflection angle disappears. That is, the electric field intensity has no orientation in a plane orthogonal to the light traveling direction axis. For this reason, the electric field intensity of the light transmitted through the transmission axis direction of the linear polarization unit 40 is “α · E”, and the electric field intensity of the light transmitted through the transmission orthogonal axis direction is “R · α · E” (however, 0 ≦ α ≦ 1). However, “R” is an extinction ratio, and is expressed as “R = transmission light amount on the transmission orthogonal axis / transmission light amount on the transmission axis”.

In this case, when the outgoing light from the linear polarization unit 50 is separated into orthogonal components along the XY axis, the X component and the Y component of the electric field vector are expressed by the following equations (4) and (5), respectively.

At this time, when the azimuth angle χ of linearly polarized light is calculated using the X component and Y component of the electric field vector, the following equation (6) is obtained.

  From equation (6), it can be seen that the azimuth angle χ of linearly polarized light does not depend on the angle Δθ but is determined by the transmission axis angle φ. The fact that the azimuth angle χ does not depend on the angle Δθ means that the linearly polarized light emitted from the linear polarization unit 40 does not depend on the fluctuation of the light source light. Therefore, by using the linearly polarized light purity improver 1A shown in FIG. 1, high-purity linearly polarized light that does not depend on the fluctuation of the light source light can be obtained.

  The configuration of the linear polarization purity improver 1 in the present embodiment is not limited to the configuration of the linear polarization purity improver 1A shown in FIG. For example, the linear polarization purity improver 1 is configured so that the light source light is not directly incident on the circular polarization unit 40 but is linearly polarized by a linear polarizer and then incident on the circular polarization unit 40. Also good.

FIG. 2 is a diagram showing the configuration of the linear polarization purity improver 1B in this case.
The linear polarization purity improver 1 </ b> B includes a front-stage linear polarization unit 30, a circular polarization unit 40, and a linear polarization unit 50. 1 is different from the linear polarization purity improver 1A in FIG. 1 in that a front linear polarization unit 30 that linearly polarizes light incident on the circular polarization unit 40 is provided in a front part of the circular polarization unit 40.

  The front-stage linear polarization unit 30 is a polarization element that linearly polarizes the light source light before the circular polarization unit 40. Like the linear polarization unit 50, the pre-stage linear polarization unit 30 includes a linear polarizer using a polarization optical element such as a Glan-Thompson prism.

  The linear polarizer and circularly polarized light included in the front linear polarization unit 30 are set so that the angle formed by the optical axis direction of the front linear polarization unit 30 and the optical axis direction of the quarter-wave plate included in the circular polarization unit 40 is 45 °. The arrangement angle with the quarter-wave plate of the unit 40 is adjusted. This is because the fast axis component and the slow axis component of the linearly polarized light incident on the circular polarization unit 40 are equalized so that the light source light incident on the circular polarization unit 40 is appropriately converted to circular polarization.

  The light transmitted through the front-stage linear polarization unit 30 is reduced in polarization components in directions other than the transmission axis by the extinction ratio of the front-stage linear polarization unit 30 compared to the original light source light. This light is circularly polarized by the circular polarization unit 40 and is allowed to pass through the linear polarization unit 50 again, whereby the polarization component in the direction other than the transmission axis can be further reduced by the extinction ratio of the linear polarization unit 50. For this reason, the linearly polarized light purity improver 1B can obtain higher-purity linearly polarized light than the linearly polarized light purity improver 1A.

2. Second Embodiment Next, an embodiment of a blood glucose level measuring apparatus 3 will be described as an apparatus that includes the linear polarization purity improver 1 described above and measures an optical characteristic of a measurement object. The blood glucose level measuring device 3 of the present embodiment is a kind of medical device that measures the component concentration of a predetermined known substance contained in a living body or in a body fluid of the living body, and non-invasively determines the glucose concentration in the blood of a subject. It is a device that measures automatically.

2-1. Functional Configuration FIG. 5A is a diagram illustrating a configuration example of the blood sugar level measuring apparatus 3.
The blood glucose level measuring device 3 includes, as main components, an optical device 5, a control unit 100, an operation unit 200, a display unit 300, a sound output unit 400, a communication unit 500, and a storage unit 600. Configured.

FIG. 5B is a diagram illustrating a configuration example of the optical device 5.
The optical device 5 includes a light source 10, a light conversion unit 20, a linear polarization purity improver 1 </ b> B, a polarization unit 60, a light detection unit 70, and a signal processing unit 80. The measuring object S is disposed between the linear polarization purity improver 1 </ b> B and the polarization unit 60. In the present embodiment, the measurement object S is the subject's earlobe, fingertip, hand skin, or the like.

  The light source 10 is a light generation device configured to generate and emit measurement light having a plurality of wavelengths, and is configured as a multi-wavelength laser light source, for example. The light source 10 generates and emits measurement light having an instructed wavelength under the control of the control unit 100.

  The light conversion unit 20 is a converter that converts measurement light emitted from the light source 10 into parallel light, and includes, for example, a collimator lens.

  The linear polarization purity improver 1 </ b> B linearly polarizes the measurement light emitted from the light source 10 and converted into parallel light by the light conversion unit 20. In the linear polarization purity improver 1B of the present embodiment, the circular polarization unit 40 includes a plurality of types of quarter-wave plates 42 (42-1, 42-2, 42-3,...) Corresponding to the wavelength of the measurement light. ) Is configured to be replaceable.

  In general, the refractive index of a quarter wavelength plate changes depending on the wavelength of incident light, and the phase difference provided by the quarter wavelength plate is wavelength dependent. In this embodiment, in order to measure the concentration of glucose (blood glucose level) contained in blood of a living body, the optical rotation is measured using measurement light having a plurality of wavelengths. Therefore, in order to make it possible to measure the optical rotation using a suitable quarter-wave plate 42 for each wavelength (hereinafter referred to as “measurement wavelength”) used for measuring the glucose concentration, A plurality of types of ¼ wavelength plates 42 can be replaced.

  The polarization unit 60 is a polarizer that polarizes the transmitted light that is transmitted from the measurement object S by the linearly polarized light emitted from the linear polarization purity improver 1B. As the polarization unit 60, an optical element having an orthogonal separation function for separating transmitted light into orthogonal components, that is, polarized components different from each other by 90 degrees can be used. For example, a Wollaston prism can be applied.

  The light detection unit 70 is a light receiving element that receives the transmitted light polarized by the polarization unit 60 and includes a photodetector such as a photodiode. The light detection unit 70 includes, for example, two light detectors, and receives the mutually orthogonal polarization components (P polarization component and S polarization component) that are orthogonally separated by the polarization unit 60. In this case, it is preferable to use the photodetectors of the same standard as the two photodetectors.

  The signal processing unit 80 includes a circuit (signal processing circuit) that performs signal processing on the light detection signal output from the light detection unit 70. When the light detection unit 70 is configured to output a detection signal having a voltage corresponding to the amount of received light, for example, the voltage is amplified at a predetermined amplification rate and then output to the control unit 100. When the light detection unit 70 is configured to output a detection signal of a current corresponding to the amount of received light, the current-voltage conversion is performed to convert the current into a voltage, which is then amplified and the control unit 100 Output to.

  The control unit 100 is a control device and an arithmetic device that comprehensively control each unit of the blood glucose level measuring device 3, and is a microprocessor such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor) or an ASIC (Application Specific Integrated Circuit). ) And the like.

  The control unit 100 controls the light source 10 to emit measurement light having the measurement wavelength for each of the plurality of measurement wavelengths. In this case, the measurement light of the measurement wavelength is emitted to the light source 10 with the quarter wavelength plate 42 corresponding to the measurement wavelength inserted. The replacement of the quarter wave plate 42 can be performed manually or automatically.

  When the quarter-wave plate 42 is manually replaced, each time measurement is performed using measurement light having a different wavelength, the operator uses the quarter-wave plate 42 corresponding to the wavelength of the measurement light as the optical device. 5 is inserted at a fixed position to perform measurement.

  When the quarter wavelength plate 42 is automatically replaced, the optical device 5 is provided with an advance / retreat mechanism that slides the quarter wavelength plate 42 forward and backward to a fixed position of the optical device 5. 100 may control the advance / retreat mechanism so that the quarter-wave plate 42 corresponding to the measurement wavelength is advanced / retreated by the advance / retreat mechanism.

  The control unit 100 calculates the optical rotation of the measurement target S at the measurement wavelength using the processing result of the signal processing unit 80 when the measurement target S (biological body) is irradiated with measurement light having a plurality of measurement wavelengths. To do. Then, the concentration of glucose contained in the blood of the living body is calculated and measured using the optical rotation calculated for each measurement wavelength. Since the blood sugar level measuring apparatus 3 of the present embodiment has a function of measuring the optical rotation, it can be said that the blood glucose measuring apparatus 3 includes an optical measuring apparatus that measures the optical rotation of the measurement object S. In addition, since a conventionally well-known method can be applied about the calculation method of optical rotation, description is abbreviate | omitted in this specification.

In general, it is known that the optical rotation of a substance having optical activity is proportional to the concentration. Α _i (λ) [(° · g) / (dm · ml)] and component concentration c for specific rotation (wavelength 10 cm = 1 dm, optical rotation angle per concentration 1 g / ml) at wavelength λ _{When i} [g / dl] and the length parallel to the optical axis of the measuring object S are d [mm], the optical rotation θ (λ) [°] of the measuring object S composed of a plurality of components is 7).

In this embodiment, the concentration of glucose (blood glucose level) contained in blood is calculated. Therefore, the specific rotation α _i (λ) of the known substance contained in the blood is obtained in advance and stored in the storage unit 600, and the same number as the number of known substances desired to be distinguished in the blood or The glucose concentration is obtained by solving simultaneous equations obtained by simultaneous equations (7) for the measurement wavelengths longer than that. The blood glucose level measurement result is notified to the subject by, for example, displaying the blood glucose level on the display unit 300 in a numerical value or graph format.

  The operation unit 200 is an input device that includes a button switch and the like, and outputs a signal of a pressed button to the control unit 100. By the operation of the operation unit 200, an instruction operation such as start of blood glucose level measurement or end of measurement is performed.

  The display unit 300 is a display device that performs various displays based on display signals input from the control unit 100. Information such as the measured blood glucose level is displayed on the display unit 300.

  The sound output unit 400 is a sound output device that outputs various sounds based on a sound output signal input from the control unit 100. For example, notification sounds such as measurement start, measurement end, and error occurrence are output.

  The communication unit 500 is a communication device for transmitting / receiving information used inside the device to / from an external information control device under the control of the control unit 100. As a communication method of the communication unit 500, various methods such as a wired connection via a cable compliant with a predetermined communication standard and a wireless connection using short-range wireless communication can be applied. The communication method may be wired / wireless.

  The memory | storage part 600 memorize | stores the various programs, data, etc. for implement | achieving various functions, such as the system program of the blood glucose level measuring device 3, an optical rotation measuring function, and a blood glucose level measuring function. In addition, it has a work area for temporarily storing data being processed and results of various processes.

2-2. In the blood glucose level measuring device 3, the optical device 5 includes the light source 10, the light conversion unit 20, the linear polarization purity improver 1B, the polarization unit 60, the light detection unit 70, and the signal processing unit 80. Configured. The circular polarization unit 40 of the linear polarization purity improver 1B is configured to be able to replace a plurality of types of quarter wave plates 42 according to the wavelength of the measurement light emitted from the light source 10, and each of the plurality of measurement wavelengths. The optical rotation of the measuring object S can be measured using the optimum quarter wavelength plate 42 corresponding to the measurement wavelength.

  The high-purity linearly polarized light output from the linearly polarized light purity improver 1 </ b> B is transmitted through the measurement object S, and the transmitted light is polarized by the polarization unit 60 and detected by the light detection unit 70. Then, the detection result of the light detection unit 70 is signal-processed by the signal processing unit 80, and the optical rotation is calculated using the processing result, whereby the optical rotation of the measurement object S can be measured with high accuracy. Then, by using the optical rotation obtained for each of the plurality of measurement wavelengths, for example, by calculating the glucose concentration according to the equation (7), the blood glucose level of the subject can be measured with high accuracy. It becomes.

3. Modifications Embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be changed as appropriate without departing from the spirit of the present invention. Hereinafter, modified examples will be described. In addition, about the structure same as the said embodiment, the same code | symbol is attached | subjected and repeated description is abbreviate | omitted.

3-1. Linear Polarization Purity Improvement Device As an application example of the linear polarization purity improver 1 of the above embodiment, a linear polarization purity improvement device 2 described below may be configured.

FIG. 6 is a diagram illustrating a configuration of a linearly polarized light purity improving apparatus 2 </ b> A that is an example of the linearly polarized light purity improving apparatus 2.
The linearly polarized light purity improving apparatus 2A includes linearly polarized light purity improvers 1A (1) and 1A (2). In this configuration, the linear polarization purity improver 1A is provided in two stages in series. The circular polarization unit 40 of the linear polarization purity improver 1A at each stage is configured to have a quarter wavelength plate. Further, the optical axis direction of the linear polarizer included in the linear polarization unit 50 (1) of the first-stage linear purity improver 1A (1) and the circular polarization unit of the second-stage linear purity improver 1A (2). The angle formed by the optical axis direction of the quarter wavelength plate of 40 (2) is 45 °.

  Since the linear polarization unit 50 transmits light slightly in directions other than the transmission axis direction, it is difficult to obtain complete linear polarization. However, in the linear polarization purity improving apparatus 2A, the linear polarization purity improver 1A has two stages, and the circular polarization and the linear polarization of the measurement light are repeated twice. When the circularly polarized light passes through the linear polarization unit 50, the amount of light transmitted through the transmission orthogonal axis is reduced by the extinction ratio with respect to the light transmitted through the transmission axis direction of the linear polarization unit 50. For this reason, it becomes possible to obtain higher-purity linearly polarized light by repeating circular polarization and linear polarization.

FIG. 7 is a diagram illustrating a configuration of a linearly polarized light purity improving apparatus 2 </ b> B that is another example of the linearly polarized light purity improving apparatus 2.
The linearly polarized light purity improving apparatus 2B includes a front-stage linearly polarized light unit 30 and linearly polarized light purity improvers 1A (1) and 1A (2). That is, the linear polarization purity improver 1A is provided in two stages, and the light incident on the circular polarization unit 40 of the first stage linear polarization purity improver 1A is linearly polarized before the first stage linear polarization purity improver 1A. This is a configuration in which a front linear polarization unit 30 is added.

  The optical axis direction of the linear polarizer included in the front linear polarization unit 30 and the optical axis direction of the quarter wavelength plate included in the circular polarization unit 40 (1) of the linear polarization purity improver 1A (1) in the first stage. The formed angle is 45 °. Further, the optical axis direction of the linear polarizer included in the linear polarization unit 50 (1) of the first stage linear polarization purity improver 1A (1) and the circular polarization of the second stage linear polarization purity improver 1A (2). The angle formed with the optical axis direction of the quarter-wave plate included in the portion 40 (2) is configured to be 45 °.

  In the linear polarization purity improving apparatus 2B, since the incident light is linearly polarized by the previous stage linear polarization unit 30, circular polarization and linear polarization are repeated twice. Compared to the linear polarization purity improvement apparatus 2A in FIG. Even higher purity linearly polarized light can be obtained.

  6 and 7, the linear polarization purity improvement devices 2A and 2B are described as examples of the linear polarization purity improvement device 2 having the two-stage linear polarization purity improver 1A. Of course, the linearly polarized light purity improving apparatus 2 having the purity improver 1A may be configured.

3-2. Optical Measurement Device In the second embodiment described above, the optical measurement device including the linear polarization purity improver 1B of FIG. 2 has been described as an example of the optical measurement device that measures the optical rotation of the measurement object. However, instead of the linear polarization purity improver 1B, the optical polarization device may be provided with the linear polarization purity improver 1A of FIG. Moreover, the linear polarization purity improving apparatus 2A in FIG. 6 and the linear polarization purity improving apparatus 2B in FIG. 7 may be provided in the optical measuring device.

  In addition, the optical measuring device is not limited to a device that measures the optical rotation of a measurement object. For example, it may be an apparatus that performs various optical measurements, such as an absorption measurement apparatus that measures the absorbance of a light-absorbing substance and a polarization polarization plane analysis apparatus that analyzes the polarization polarization plane.

  In addition to the blood glucose level measuring device of the above embodiment, for example, an optical measuring device that measures the optical rotation using the measurement object as a fruit, and the sugar content of the fruit using the optical rotation measured by the optical measuring device. It is also possible to configure a sugar content measuring device including a sugar content measuring unit for measuring.

3-3. Measurement Object In the second embodiment, the measurement object is a predetermined part having biological permeability, such as a living earlobe, fingertip, or finger skin, but the measurement object may be a body fluid of the living body. The body fluid in this case is not limited to blood, but may be lymph fluid, interstitial fluid, body cavity fluid, or the like. When the measurement target is a body fluid, the body fluid is sealed in a sample container such as a cuvette, and linearly polarized light from the sample container is incident, and the blood optical rotation is measured in the same procedure as in the above embodiment. Good.

3-4. In the second embodiment, the embodiment of the blood sugar level measuring device that measures the concentration of glucose contained in blood has been described as the medical device. However, the medical device is not limited to this. is there. For example, it is possible to configure a medical device that measures the concentration of hemoglobin contained in blood. When the body fluid is an interstitial fluid, it is also possible to configure a medical device that measures the concentration of components such as proteins, amino acids, and fatty acids contained in the interstitial fluid.

3-5. Light Source It is also possible to construct a light source that generates and emits high-purity linearly polarized light by incorporating the linearly polarized light purity improver 1 and the linearly polarized light purity improving apparatus 2 of the above-described embodiment in a light source.

FIG. 8 is a diagram illustrating a configuration example of the light source 12 in this case.
The light source 12 includes a light generation unit 14 and a linear polarization purity improver 1A. In this configuration, a linear polarization purity improver 1A is provided at the output stage of the emitted light.

  The light generation unit 14 is a generation device that generates laser light having a predetermined wavelength, and includes, for example, a laser oscillator. The laser beam generated by the light generator 14 enters the linear polarization purity improver 1A.

  The linearly polarized light purity improver 1A generates high-purity linearly polarized light according to the above principle using the laser light emitted from the light generation unit 14 as incident light. That is, the incident light emitted from the light generation unit 14 and incident on the circular polarization unit 40 is emitted from the linear polarization unit 50 with linearly polarized light having a higher linear polarization purity than the incident light.

  For example, the light source 12 can be included in an optical measurement device such as the blood glucose level measurement device described in the above embodiment. In this case, what is necessary is just to comprise an optical measurement apparatus so that the emitted light from the light source 12 may be directly irradiated to a measurement object.

  Instead of the linear polarization purity improver 1A, the light source 12 includes the linear polarization purity improver 1B of FIG. 2, the linear polarization purity improver 2A of FIG. 6, and the linear polarization purity improver 2B of FIG. Of course, it is good.

3-6. Polarization Optical Element In the above embodiment, the pre-stage linear polarization unit 30 and the linear polarization unit 50 are described as having, for example, a Glan-Thompson prism, but as a configuration having other polarization optical elements. Of course, it is also good. For example, it is good also as a structure which has the Grand Taylor prism which is the optical element for polarization | polarized-light of the same gran type.

  In the above-described embodiment, the polarizing unit 60 has been described as having a Wollaston prism, for example. However, the polarizing optical element forming the polarizing unit 60 can be changed as appropriate. For example, it is good also as a structure which has the optical element for polarization | polarized-light which has orthogonal separation function, such as a grand laser prism and a lotion prism.

  DESCRIPTION OF SYMBOLS 1 Linear polarization purity improvement device, 2 Linear polarization purity improvement apparatus, 3 Blood glucose level measurement apparatus, 5 Optical apparatus, 10, 12 Light source, 14 Light generation part, 20 Light conversion part, 30 Pre-stage linear polarization part, 40 Circular polarization part, 50 linear polarization unit, 60 polarization unit, 70 light detection unit, 80 signal processing unit, 100 control unit, 200 operation unit, 300 display unit, 400 sound output unit, 500 communication unit, 600 storage unit

Claims (8)

A circular polarization section;
A linear polarization unit that linearly polarizes the light emitted from the circular polarization unit;
A linearly polarized light purity improver that emits linearly polarized light incident on the circularly polarized light portion from the linearly polarized light portion as linearly polarized light having a higher linear polarization purity than the incident light. A pre-stage linear polarization unit provided in a stage before the circular polarization unit that linearly polarizes light incident on the circular polarization unit;
The circular polarization unit has a quarter wavelength plate, and an angle formed between the optical axis direction of the front linear polarization unit and the optical axis direction of the quarter wavelength plate is configured to be 45 °.
The linearly polarized light purity improver according to claim 1. The circularly polarizing unit has a plurality of types of quarter wave plates that can be replaced according to the wavelength of incident light,
The linearly polarized light purity improver according to claim 1 or 2.   A linear polarization purity improving apparatus comprising the linear polarization purity improver according to claim 1 in a plurality of stages. The linear polarization purity improver according to claim 1 is provided in a plurality of stages,
The front stage of the linear polarization purity improver in the first stage further comprises a front stage linear polarization section that linearly polarizes light incident on the circular polarization section of the first stage linear polarization purity improver.
Linear polarization purity improvement device. The circular polarization part of the linear polarization purity improver at each stage has a quarter wavelength plate, the optical axis direction of the linear polarization part located immediately before the circular polarization part, and the optical axis of the quarter wavelength plate. The angle formed with the direction is 45 °,
The linearly polarized light purity improving apparatus according to claim 4 or 5.   The linearly polarized light purity improver according to any one of claims 1 to 3, or the linearly polarized light purity improver according to any one of claims 4 to 6 (hereinafter collectively referred to as "linearly polarized purity improvement"). An optical measurement device that transmits the light emitted from the linear polarization purity improver to the measurement object and measures the optical rotation of the measurement object based on the transmitted light. The optical measurement device according to claim 7, wherein the optical rotation is measured using the measurement object as a predetermined part having permeability of a living body or a body fluid of the living body,
A component concentration calculator that measures the component concentration of a predetermined substance using the optical rotation measured by the optical measurement device;
With medical equipment.

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