JP2010088556A - Medication apparatus and wavelength variable filter used therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a medication apparatus which is noninvasive for measuring a distribution of drug concentration in a living body accurately and quickly, and controlling the medication amount based on the measured result. <P>SOLUTION: The medication apparatus 1 includes a medicine administration device 2, a light source 3 for applying a light, and a liquid crystal filter 4 (wavelength variable filter) where the light is emitted from a labeling agent out of a living body when the labeling agent is applied with the light to make the light income, an area sensor 5 (light detecting means) for detecting the strength of the incident light through the liquid crystal filter 4 and obtaining the strength distribution of the light emitted from a plurality of positions to be measured, and DSP6 (control means) for calculating the concentration of the medicine administrated with the labeling agent from the light strength distribution obtained by the area sensor 5 and controlling the medication amount from the calculated result. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a dosing device and a tunable filter used therefor.

  In the medical field, when a drug is administered to a patient, it is required to obtain information on the concentration of the drug in the patient's body in order to minimize side effects caused by the drug and obtain a sufficient therapeutic effect. For example, there are some drugs whose dosage is difficult to control when the dose is easily increased just because the concentration is low, and the blood concentration immediately enters the poisoning zone. Conventionally, as a most general technique, a method for analyzing pharmacokinetics in the body by collecting blood from a patient's vein, measuring the blood concentration, and analyzing the data has been adopted. However, in order to know accurate pharmacokinetics, it is necessary to perform blood concentration measurement at, for example, 5 to 6 time points or more, and it is practically impossible to measure blood concentration as much in daily clinical practice. In the sense of guaranteeing the therapeutic effect and safety, it is limited to the measurement at 1 to 2 time points. Accordingly, there is a need for a method capable of obtaining a drug concentration distribution in a living body by a non-invasive method.

Conventionally, the following methods have been proposed for knowing the concentration of a drug in a living body. Patent Document 1 listed below discloses a drug concentration measuring device including an organic sensor that measures the in-vivo drug concentration of a drug such as aspirin and a body temperature sensor that measures body temperature. Patent Document 2 listed below discloses a system for adaptively adjusting drug administration. In this system, changes in blood pressure, heart rate, body temperature, etc., which are physiological actions of a patient when a drug is administered, are changed over time. A method of detecting the drug concentration by measuring the concentration of the drug is used. In addition, although it is not a method for measuring the concentration, in Patent Document 3 below, a contrast agent is administered to a lymphatic vessel, and then a laser beam is irradiated to an observation site, and near infrared rays emitted from the contrast agent at that time are detected. A lymphatic vessel observation device that can percutaneously observe lymphatic vessels by detection is disclosed.
JP 2007-294214 A Special table 2007-519487 JP-A-2005-212355

However, none of the techniques of Patent Documents 1 to 3 described above can satisfy the above requirements.
In the method of Patent Document 1, when using an organic sensor, it is necessary to puncture a fingertip or the like and attach blood to a test paper. That is, the method of Patent Document 1 cannot measure the drug concentration distribution non-invasively. Moreover, since the method of patent document 2 is a method of measuring the physiological effect of a patient when a drug is administered, individual differences occur in the measurement results, the reproducibility of the measurement results is inferior, and the measurement takes a long time. There was a problem such as. Moreover, although the apparatus of Patent Document 3 can observe a lymphatic vessel, it cannot measure a drug concentration distribution.

  The present invention has been made to solve the above-described problems, and a dosing device capable of accurately and rapidly measuring a drug concentration distribution in a living body in a non-invasive manner and capable of performing appropriate dosing based on the measurement result. An object of the present invention is to provide a tunable filter used in the above.

  The dosing device of the present invention includes a dosing unit for dosing the living body, a light source for irradiating light to the living body to be measured, and the labeling agent when the light is irradiated from outside the living body to the labeling agent. Light emitted outside the living body is incident, transmits light in a predetermined wavelength range out of the entire wavelength range of incident light, and enters through the wavelength tunable filter capable of changing the wavelength range, and the wavelength tunable filter. A light detecting means for detecting the intensity of the emitted light and obtaining an intensity distribution of the light emitted from the plurality of positions of the measurement object; and a light intensity distribution at the plurality of positions of the measurement object obtained by the light detection means. And a control means for calculating the concentration of the drug administered together with the labeling agent based on the above and controlling the dosage by the dosing means based on the concentration calculation result of the drug.

  The dosing device of the present invention is a device that measures the concentration distribution of a drug in a living body to which a labeling agent having a contrast function and the drug are administered, and performs dosing based on the measurement result. When the labeling agent is irradiated with light from a living body using a light source, light having a wavelength of about 600 nm or less is absorbed by hemoglobin, and light having a wavelength of about 1500 nm or more is absorbed by water. And is irradiated to the labeling agent in the blood vessel. Then, in the labeling agent having a contrast function, light is emitted using the irradiated light as excitation light, or a part of the light is absorbed and the remaining light is reflected, and light with a wavelength of about 700 to 1400 nm is emitted from the living body. Released outside.

  Here, since the light intensity generally increases as the concentration of the labeling agent increases, the light detecting means detects the intensity of light incident through the wavelength tunable filter while changing the transmission wavelength range of the wavelength tunable filter. The intensity distribution (spectrum) of light emitted from a plurality of positions to be measured is acquired. The control means has data on the correlation between the light intensity distribution and the concentration of the labeling agent and the correlation between the drug concentration in advance, and the labeling is performed based on the light intensity distribution at a plurality of positions of the measurement target acquired by the light detection means. Calculate the concentration of the drug administered with the drug. At this time, in the apparatus of the present invention, the drug concentration is calculated not from the intensity value of light of a specific wavelength alone but from the light intensity distribution in a predetermined wavelength band such as about 700 to 1400 nm. The concentration can be calculated with high accuracy. Then, the dosage by the medication means is precisely controlled based on the highly accurate drug concentration calculation result. Thus, according to the dosing device of the present invention, the concentration distribution of the drug can be measured accurately and quickly by detecting the light emitted from the living body by a non-invasive method without collecting blood or the like. Based on this, an appropriate dosage can be administered.

  According to another dosing device of the present invention, there is provided a dosing unit for dosing a living body, a light source for irradiating light on a living body to be measured, and the medicine when the light is irradiated from outside the living body. Light emitted outside the living body is incident, transmits light in a predetermined wavelength range out of the entire wavelength range of incident light, and enters through the wavelength tunable filter capable of changing the wavelength range, and the wavelength tunable filter. A light detecting means for detecting the intensity of the emitted light and obtaining an intensity distribution of the light emitted from the plurality of positions of the measurement object; and a light intensity distribution at the plurality of positions of the measurement object obtained by the light detection means. Control means for calculating the concentration of the drug based on the drug and controlling the dosage by the dosing means based on the concentration calculation result of the drug.

  Another dosing device of the present invention is a device that measures the concentration distribution of a drug in a living body to which a drug having a contrast function is administered, and performs dosing based on the measurement result. That is, if a drug having a contrast function can be administered to a living body, it is not necessary to use a labeling agent having a contrast function. In this dosing device, the same actions and effects as described above can be obtained, the drug concentration distribution can be measured accurately and quickly by a non-invasive method, and an appropriate dose is administered based on the measurement result. Can do.

In the present invention, the wavelength tunable filter includes a liquid crystal cell including a pair of polarizers, a liquid crystal layer sandwiched between the pair of polarizers, and an electrode for applying a voltage to the liquid crystal layer. It is desirable to have multiple sets.
When a filter with multiple sets of liquid crystal cells is used as a wavelength tunable filter, the transmission wavelength range can be optimized and the transmission wavelength range can be optimized by setting the cell thickness when manufacturing each liquid crystal cell and adjusting the applied voltage during use. Can be easily changed.

In the present invention, it is desirable that an optical filter for blocking light having a wavelength of 650 nm or less is provided on the incident side of the light detection means.
According to this configuration, light having a wavelength of 650 nm or less generated when a wavelength tunable filter using a liquid crystal cell is used can be blocked, and light intensity detection accuracy can be improved by removing noise components.

The wavelength tunable filter of the present invention is used in a device that measures the concentration distribution of a drug in a living body to which a labeling agent having a contrast function and a drug or a drug having a contrast function is administered, and that dispenses based on the measurement result. A plurality of liquid crystal cells each including a pair of polarizers, a liquid crystal layer sandwiched between the pair of polarizers, and an electrode for applying a voltage to the liquid crystal layer. The transmission axes of the pair of polarizers are parallel to each other, the liquid crystal layer has liquid crystal molecules that are homogeneously aligned, and the angle formed by the transmission axes of the pair of polarizers and the alignment direction of the liquid crystal molecules is 45. The liquid crystal layer satisfies the following formula (1), where Δn is the optical anisotropy of the liquid crystal layer with respect to light having a wavelength of 590 nm, and d is the layer thickness of the liquid crystal layer.
2 ^m (1.034 × Δn ^−0.90 ) <d <2 ^m (2.266 × Δn ^−0.82 ) (1)
(However, m = 0, 1, 2, 3, 4, 5)

  According to this configuration, the maximum wavelength of the peak value that can be detected by the wavelength tunable filter can be in the range of 800 nm to 1400 nm. Thereby, for example, a wavelength tunable filter suitable for using a labeling agent that emits light in the vicinity of a wavelength of 1100 nm can be obtained. Details will be described later.

Furthermore, in the present invention, it is more desirable to satisfy the following formula (2), where Δn is the optical anisotropy of the liquid crystal layer with respect to light having a wavelength of 590 nm, and d is the thickness of the liquid crystal layer.
^{2 m (1.245 × Δn -0.89)} <d <2 m (1.865 × Δn -0.83) ... (2)
(However, m = 0, 1, 2, 3, 4, 5)

  According to this configuration, the maximum wavelength of the peak value that can be detected by the wavelength tunable filter can be in the range of 900 nm to 1300 nm. Thereby, for example, a more tunable filter can be obtained by using a labeling agent that emits light in the vicinity of a wavelength of 1100 nm. Details will be described later.

The present invention further includes a pair of polarizers, a liquid crystal layer sandwiched between the pair of polarizers, and an electrode for applying a voltage to the liquid crystal layer, wherein the transmission axes of the pair of polarizers are The liquid crystal layer is a liquid crystal layer in which liquid crystal molecules are homogeneously aligned, and an angle between the transmission axis of the pair of polarizers and the alignment direction of the liquid crystal molecules is 45 ° ± 5 °. It is desirable to have.
According to this configuration, light that becomes a noise component can be removed by the correction liquid crystal cell.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The dosing device 1 of this embodiment is an example of a device that measures the concentration distribution of a drug in a living body to which a labeling agent having a contrast function and the drug are administered, and performs dosing based on the measurement result. The subject to be measured may be a human or an animal such as a rat or a mouse that is often used in pharmacological experiments, but in the present embodiment, description will be made assuming a human (patient).
FIG. 1 is a block diagram showing a schematic configuration of a dosing device 1 of the present embodiment. FIG. 2 is a perspective view showing an image of the usage state of the medication apparatus 1.

[Device configuration]
As shown in FIG. 1, the dosing device 1 of the present embodiment includes a drug administration device 2 (dosing unit), a light source 3, a liquid crystal filter 4 (wavelength variable filter), an area sensor 5 (light detection unit), A signal processor 6 (Digital Signal Processor, DSP) (control means) and an external memory 7 are provided. The light source 3 irradiates light to a living body that is a measurement target. The liquid crystal filter 4 receives light emitted from the labeling agent when the labeling agent in the living body is irradiated with light, and transmits light in a specific wavelength region in the entire wavelength region of incident light. The area sensor 5 detects the intensity of light incident through the liquid crystal filter 4. The DSP 6 calculates the concentration of the medicine based on the light intensity distribution at a plurality of positions of the measurement target acquired by the area sensor 5. The external memory 7 stores image data obtained by the DSP 6.

  Prior to measurement of the concentration distribution of the drug, a mixture of a labeling agent having a contrast function and the drug is administered to the human body. In order to obtain in vivo information using light, it is necessary to use light having a wavelength other than the wavelength absorbed by the constituents of the living body. Light having a wavelength of about 600 nm or less is absorbed by hemoglobin, and light having a wavelength of about 1500 nm or more is absorbed by water. Therefore, light in these wavelength ranges cannot be used, and light having a wavelength of about 600 to 1500 nm is a living tissue. It penetrates relatively well. From this viewpoint, a labeling agent having a characteristic of receiving light in a wavelength region of about 600 to 1500 nm and emitting light in this wavelength region can be used for the concentration distribution measurement.

  Specifically, indocyanine green, gold nanorods, fluorescent contrast agent SF64 (trade name, manufactured by Fuji Film) or the like can be used as a labeling agent. Indocyanine green is a substance that is excited by irradiation with light having a wavelength of 750 to 780 nm and emits near infrared light having a wavelength of about 800 to 1200 nm. Examples of substances that can replace indocyanine green include patent blue and indigo carmine. Gold nanorods are rod-shaped gold nanoparticles, have strong absorbency in the near-infrared region, and can be used as a contrast agent when using near-infrared light. The fluorescent contrast agent SF64 has a characteristic of generating strong fluorescence in the near infrared region.

  The method of administering the mixture of the labeling agent and the drug includes intradermal injection, subcutaneous injection, intramuscular injection, (peripheral infusion) intravenous injection, central intravenous injection, rectal administration, transdermal administration, transpulmonary administration, nasal administration Any of invasive and non-invasive methods such as administration and intraoral administration may be used. In this embodiment, intravenous injection using the drip method is used. In that case, as the drug administration device 2, a drug administration micropump or the like capable of adjusting the dose and the administration rate of the drug can be used. In addition, for example, for transpulmonary administration, a mask or the like that covers the patient's nose and mouth can be used.

  As the light source 3, for example, a xenon lamp is used. Light having a continuous spectral spectrum from the visible region (blue region) to the infrared region is emitted from the light source 3 of the xenon lamp, and is irradiated to the human body that is the measurement target. At this time, since the pre-administered labeling agent and drug are distributed in the patient's body, when light of a part of the light from the light source is transmitted through the human body and irradiated to the labeling agent, Near infrared light is emitted from the labeling agent. For example, when indocyanine green is used as the labeling agent, the labeling agent is excited by light having a wavelength of 750 to 780 nm out of the light emitted from the light source 3, and the wavelength is about 800 to 1200 nm depending on the concentration of the labeling agent. Near infrared light is emitted. Indocyanine green is excited by near-infrared light and emits near-infrared light, but does not necessarily have to emit near-infrared light. It is sufficient that absorption or reflection in an amount corresponding to the light intensity occurs and that a predetermined amount of near infrared light is emitted.

  As will be described in detail later, the liquid crystal filter 4 has a pair of substrates, a pair of polarizers disposed on the outer surfaces of the pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, and an inner surface of the pair of substrates. The liquid crystal cell includes a plurality of sets of liquid crystal cells that are arranged and have a pair of electrodes that apply a voltage to the liquid crystal layer. In the case of the present embodiment, the area sensor 5 described later does not detect the light quantity at a certain wavelength, but needs to detect the light quantity at a plurality of wavelengths and acquire the spectrum of the emitted light. Therefore, a tunable filter capable of scanning the transmission wavelength region on the incident side of 5 is required. The liquid crystal filter 4 functions as such a wavelength variable filter. Some configuration examples of the liquid crystal filter 4 will be described later.

  As the area sensor 5, a two-dimensional imaging sensor composed of a CCD, a CMOS sensor or the like is used. In general, an imaging sensor such as a CCD or CMOS sensor has a sensitivity region including near infrared light having a wavelength of about 800 to 1200 nm. Since light is incident on the area sensor 5 through the liquid crystal filter 4, only light of a predetermined wavelength band is received at a certain time, but light of different wavelength bands is received according to scanning of the transmission wavelength band of the liquid crystal filter 4. Light is received, and the light intensity distribution (spectrum) can be acquired as the entire scanning time. The area sensor 5 transmits the intensity of the received near-infrared light as an electrical signal to the DSP 6 described later. In this example, a two-dimensional imaging sensor is used, but a one-dimensional imaging sensor, a so-called linear sensor may be used. In that case, for example, a linear sensor may be scanned over the measurement region to detect the light intensity in the two-dimensional measurement region.

  Further, although not shown in FIG. 1, an optical filter that blocks light unnecessary for the main concentration distribution measurement, for example, light having a wavelength of 700 nm or less, is arranged on the incident side of the area sensor 5 within the sensitivity region of the area sensor 5. You may do it. As this type of optical filter, an ultraviolet / visible light cut filter R-72 (trade name: manufactured by Edmund) can be used.

  The DSP 6 receives the electrical signal from the area sensor 5, calculates the concentration of the labeling agent based on the light intensity distribution at each point on the measurement target, and calculates the concentration of the drug from the concentration of the labeling agent. Thus, by calculating the concentration of the drug at each point on the measurement target, it is possible to know the drug concentration distribution in the living body as a whole. As shown in FIG. 2, the measurement data of the obtained drug concentration distribution is sent from the DSP to an arbitrary output device 9 such as a liquid crystal monitor, and the magnitude of the drug concentration is expressed by a color or its density. Users such as nurses and nurses can visually check.

[Liquid crystal filter-1]
Here, a first configuration example of the liquid crystal filter 4 will be described with reference to FIGS.
FIG. 3 is a perspective view showing the liquid crystal filter of this configuration example in an exploded state. FIG. 4 is a cross-sectional view of one liquid crystal cell constituting the liquid crystal filter. FIG. 5 is a graph showing the relationship between the voltage applied to each liquid crystal cell and the transmission peak wavelength. FIG. 6 is a diagram showing the spectral characteristics of the liquid crystal filter.
The specific numerical values such as the voltage applied to the liquid crystal cell and the transmission wavelength shown below are based on the simulation results performed by the present inventors.

  As shown in FIGS. 3 and 4, the liquid crystal filter 4 of this configuration example is disposed on a pair of glass substrates 12 and 13 bonded via a sealant 11 and on the outer surfaces of the pair of glass substrates 12 and 13. A pair of polarizing plates 14 and 15, a liquid crystal layer 16 sandwiched between the pair of glass substrates 12 and 13, and a pair of electrodes disposed on the inner surfaces of the pair of glass substrates 12 and 13 and applying a voltage to the liquid crystal layer 16 Three sets of liquid crystal cells 21a, 21b, and 21c each including electrodes 17 and 18 and alignment films 19 and 20 on each electrode are laminated. However, for the polarizing plate located between adjacent pairs of liquid crystal cells, one polarizing plate is shared by these two liquid crystal cells. In the following description, for the sake of convenience, they will be referred to as “first liquid crystal cell 21a”, “second liquid crystal cell 21b”, “third liquid crystal cell 21c”,...

  In the first to third liquid crystal cells 21a, 21b, and 21c, the pair of glass substrates 12 and 13 are parallel to each other and have opposite orientation directions, and exhibit so-called antiparallel orientation. As a result, the liquid crystal molecules constituting the liquid crystal layer 16 of each liquid crystal cell 21a, 21b, 21c are in a homogeneous alignment state. In addition, the pair of polarizing plates 14 and 15 disposed with the pair of glass substrates 12 and 13 interposed therebetween have their transmission axes parallel to each other, and the direction of the transmission axis is 45 ° with respect to the orientation direction of one substrate. They are arranged at an angle of ± 5 °. As the polarizing plates 14 and 15, an iodine-based polarizing film is not preferable because it does not have a polarizing property in the near infrared region, and a laminated reflective polarizer or a wire grid in which retardation layers and isotropic layers are alternately stacked. It is preferable to use a type reflective polarizer. Further, a drive circuit 22 for applying a voltage to these electrodes 17 and 18 is connected between the pair of electrodes 17 and 18 of each liquid crystal cell 21a, 21b and 21c.

  Over all of the first to third liquid crystal cells 21a, 21b, and 21c, the value of the optical anisotropy Δn with respect to light having a wavelength of 590 nm of the liquid crystal layer 16 of each of the liquid crystal cells 21a, 21b, and 21c is set to 0.201. . On the other hand, the layer thickness of the liquid crystal layer 16 (cell gap between the pair of substrates) is different in each of the first to third liquid crystal cells 21a, 21b, and 21c, the liquid crystal layer thickness of the first liquid crystal cell 21a is 6.5 μm, and the second The liquid crystal cell 21b has a liquid crystal layer thickness of 12.9 μm, and the third liquid crystal cell 21c has a liquid crystal layer thickness of 25.8 μm. In the liquid crystal filter 4 of this configuration example, 15 levels of spectral spectra are selected in the wavelength range of 830 to 1098 nm. Therefore, the DSP 6 controls the drive circuit so as to supply any one of the 15 levels of applied voltages to the liquid crystal cells 21a, 21b, and 21c of the liquid crystal filter 4. The DSP 6 applies substantially the same voltage to the first to third liquid crystal cells 21a, 21b, and 21c, but corrects a minute voltage with reference to correction data stored in advance in a memory.

  When capturing the intensity of light emitted from the measurement object as image data, first, the voltage applied to the first to third liquid crystal cells 21a, 21b, and 21c is set to 0V. Then, the liquid crystal filter 4 exhibits a transmission characteristic having a peak at 1098 nm, transmits light with a wavelength of 1098 nm, and this light is incident on the arrayed pixel surface of the area sensor 5. Here, the area sensor 5 sequentially detects the intensity of incident light for each pixel, reads the entire image for one screen in 30 msec, converts it into an electrical signal, and outputs it to the DSP 6. The DSP 6 stores image data for one screen at a wavelength of 1098 nm in the external memory 7. Thus, the selected image data capturing process in the first cycle is completed.

  Next, the voltage applied to the first to third liquid crystal cells 21a, 21b, and 21c is set to 1.0V. Then, the liquid crystal filter 4 exhibits a transmission characteristic having a peak at 1077 nm, and light having a wavelength of 1077 nm enters the area sensor. The area sensor reads an image for one screen in 30 msec, converts it into an electrical signal, and outputs it to the DSP 6. The DSP 6 stores image data for one screen at a wavelength of 1077 nm in the external memory 7. Thus, the selected image data capturing process in the second cycle is completed.

Hereinafter, as shown in Table 1, the voltage applied to the first to third liquid crystal cells 21a, 21b, and 21c is 1.10V, 1.15V, 1.18V, 1.21V, 1. 23V, 1.26V, 1.28V, 1.30V, 1.32V, 1.34V, 1.35V, 1.37V, 1.39V (only the first liquid crystal cell 21a is corrected to 1.42V in the last cycle) ) And change. Then, the transmission peak wavelength changes to 1057 nm, 1018 nm, 999 nm, 980 nm, 962 nm, 944 nm, 927 nm, 910 nm, 893 nm, 877 nm, 861 nm, 845 nm, and 830 nm according to this voltage change. This completes the selection image data fetching process for all 15 cycles.

  FIG. 5 is a graph showing the data in Table 1. That is, FIG. 5 is a graph showing the relationship between the voltage applied to each of the liquid crystal cells 21a, 21b, and 21c and the transmission peak wavelength. The vertical axis represents the applied voltage (V), and the horizontal axis represents the transmission peak wavelength (nm). Show. FIG. 6 shows the spectral characteristics of the liquid crystal filter based on these transmission peak wavelength values. That is, according to this configuration example, it is possible to realize a liquid crystal filter having a spectral wavelength characteristic shown in FIG. 6 and having a transmission wavelength range of a wavelength of 800 to 1100 nm. In addition, in the spectrum of FIG. 6, a wavelength component of 700 nm or less becomes a noise component unnecessary for this concentration distribution measurement, and therefore it is desirable to remove it using the above-described optical filter.

[Liquid crystal filter-2]
A second configuration example of the liquid crystal filter will be described with reference to FIGS.
FIG. 7 is a perspective view showing the liquid crystal filter of this configuration example in an exploded state. FIG. 8 is a diagram showing the spectral characteristics of the liquid crystal filter. In FIG. 7, the same components as those in FIG. 3 of the first configuration example are denoted by the same reference numerals, and detailed description thereof is omitted.

  Whereas the liquid crystal filter of the first configuration example has a configuration in which three sets of liquid crystal cells 21a, 21b, and 21c are stacked, the liquid crystal filter of the configuration example has four sets of liquid crystal cells 21a, 21b, 21c, and 21d. The difference is in the configuration. In the liquid crystal filter of this configuration example, as shown in FIG. 7, a fourth liquid crystal cell 21d is stacked below the third liquid crystal cell 21c. The alignment direction of the fourth liquid crystal cell 21d and the transmission axis direction of the polarizing plate are the same as those of the first to third liquid crystal cells 21a, 21b, and 21c. However, the liquid crystal layer thickness is different, the liquid crystal layer thickness of the first liquid crystal cell 21a is 6.5 μm, the liquid crystal layer thickness of the second liquid crystal cell 21b is 12.9 μm, the liquid crystal layer thickness of the third liquid crystal cell 21c is 25.8 μm, The liquid crystal layer thickness of the fourth liquid crystal cell 21d is 51.6 μm.

The relationship between the applied voltage and the transmission peak wavelength for each of the liquid crystal cells 21a, 21b, 21c, and 21d is as shown in Table 2. The applied voltages to the first to third liquid crystal cells 21a, 21b, and 21c are the same, and the applied voltages to the fourth liquid crystal cell 21d are substantially the same as the applied voltages to the first to third liquid crystal cells 21a, 21b, and 21c. Make some adjustments.

  FIG. 8 shows the spectral characteristics of the liquid crystal filter based on the transmission peak wavelength values in Table 2. According to this configuration example, it is possible to realize a wavelength tunable filter having a spectral wavelength characteristic illustrated in FIG. 8 and having a wavelength range of 800 to 1100 nm. In addition, compared with the first configuration example, by changing the liquid crystal cell from three layers to four layers, the half width of the transmission wavelength region is as wide as 70 to 90 nm in the first configuration example. It was as narrow as 50 nm. Thereby, the detection accuracy of the labeling agent concentration can be improved.

[Liquid crystal filter-3]
A third configuration example of the liquid crystal filter will be described.
The liquid crystal filter of this configuration example has a configuration in which four sets of liquid crystal cells 21a, 21b, 21c, and 21d are stacked as in the liquid crystal filter of the second configuration example. The alignment directions of the liquid crystal cells 21a, 21b, 21c, and 21d and the transmission axis direction of the polarizing plate are the same as those in the second configuration example. However, the liquid crystal layer thickness is different, the liquid crystal layer thickness of the first liquid crystal cell 21a is 6.5 μm, the liquid crystal layer thickness of the second liquid crystal cell 21b is 12.9 μm, the liquid crystal layer thickness of the third liquid crystal cell 21c is 51.6 μm, The liquid crystal layer thickness of the fourth liquid crystal cell 21d is 51.6 μm. That is, in this configuration example, the same third liquid crystal cell 21c as the fourth liquid crystal cell 21d is used.

Table 3 shows the relationship between the voltage applied to each of the liquid crystal cells 21a, 21b, 21c, and 21d and the transmission peak wavelength. The same voltage is applied to the first and second liquid crystal cells 21a and 21b, and a voltage higher than that of the first and second liquid crystal cells 21a and 21b is applied to the third liquid crystal cell 21c. The applied voltage to the fourth liquid crystal cell 21d is substantially the same as that of the first and second liquid crystal cells 21a and 21b, but is slightly adjusted.

  Although not shown, also in the case of this configuration example, a wavelength tunable filter having substantially the same spectral characteristics as the liquid crystal filter of the second configuration example can be realized. In the case of this configuration example, unlike the second configuration example, the third liquid crystal cell 21c having the same specifications as the fourth liquid crystal cell 21d can be used, so that there is an advantage that the liquid crystal filter can be easily manufactured.

[Liquid crystal filter-4]
A fourth configuration example of the liquid crystal filter will be described.
The liquid crystal filter of this configuration example has a configuration in which four sets of liquid crystal cells 21a, 21b, 21c, and 21d are stacked, like the liquid crystal filters of the second and third configuration examples. The alignment directions of the liquid crystal cells 21a, 21b, 21c, and 21d and the transmission axis direction of the polarizing plate are the same as those in the second and third configuration examples. However, the liquid crystal layer thickness is different, the liquid crystal layer thickness of the first liquid crystal cell 21a is 12.9 μm, the liquid crystal layer thickness of the second liquid crystal cell 21b is 12.9 μm, the liquid crystal layer thickness of the third liquid crystal cell 21c is 51.6 μm, The liquid crystal layer thickness of the fourth liquid crystal cell 21d is 51.6 μm. That is, the same thing as the 2nd liquid crystal cell 21b was used for the 1st liquid crystal cell 21a, and the same thing as the 4th liquid crystal cell 21d was used for the 3rd liquid crystal cell 21c.

The relationship between the applied voltage and the transmission peak wavelength for each liquid crystal cell 21a, 21b, 21c, 21d is as shown in Table 4. A voltage higher than that of the second liquid crystal cell 21b is applied to the first liquid crystal cell 21a. The applied voltage to the third liquid crystal cell 21c is substantially the same as that of the first liquid crystal cell 21a, and the applied voltage to the fourth liquid crystal cell 21d is substantially the same as that of the second liquid crystal cell 21b, but both are slightly adjusted.

  Although illustration is omitted, also in the case of this configuration example, a wavelength tunable filter having substantially the same spectral characteristics as the liquid crystal filters of the second and third configuration examples can be realized. In the case of this configuration example, the first liquid crystal cell 21a can have the same specifications as the second liquid crystal cell 21b, and the third liquid crystal cell 21c can have the same specifications as the fourth liquid crystal cell 21d. Compared to the example, there is an advantage that the manufacture of the liquid crystal filter becomes easier.

[Liquid crystal filter-5]
A fifth configuration example of the liquid crystal filter will be described.
In the first to fourth configuration examples, the value of the optical anisotropy Δn with respect to light having a wavelength of 590 nm of each of the liquid crystal cells 21a, 21b, 21c, and 21d is set to 0.201. The value of the optical anisotropy Δn with respect to light having a wavelength of 590 nm of 21b, 21c, and 21d was set to 0.136. The liquid crystal layer thickness is also changed in accordance with the change in the value of the optical anisotropy Δn, the liquid crystal layer thickness of the first liquid crystal cell 21a is 9.0 μm, the liquid crystal layer thickness of the second liquid crystal cell 21b is 18.0 μm, The liquid crystal layer thickness of the 3 liquid crystal cell 21c was 36.1 μm, and the liquid crystal layer thickness of the fourth liquid crystal cell 21d was 72.1 μm.

  Although illustration is omitted, also in the case of this configuration example, a wavelength tunable filter having substantially the same spectral characteristics as the liquid crystal filters of the second to fourth configuration examples can be realized. That is, it has been found that even if the value of the optical anisotropy Δn of the liquid crystal layer is changed, a wavelength tunable filter suitable for the present invention can be obtained if an appropriate liquid crystal layer thickness d is set accordingly.

[Relationship between Δn and d in liquid crystal filter]
Next, spectral characteristics when the optical anisotropy Δn (hereinafter referred to as Δn (590 nm)) and the liquid crystal layer thickness d of the liquid crystal cell with respect to light having a wavelength of 590 nm were changed were examined. The result will be described.
Here, the liquid crystal layer thickness dm of the m-th liquid crystal cell satisfies the relationship of dm = 2 ^m × d0, where d0 is the liquid crystal layer thickness of the first liquid crystal cell.

  The optical anisotropy Δn (590 nm) of the liquid crystal cell and the liquid crystal layer thickness d were changed to various values to obtain the maximum value λmax of the transmission peak wavelength of the liquid crystal filter. FIG. 9 shows the relationship between the optical anisotropy Δn (590 nm) and the liquid crystal layer thickness d0 of the first liquid crystal cell for each maximum value λmax of the transmission peak wavelength of the liquid crystal filter. In FIG. 9, the horizontal axis represents the optical anisotropy Δn (590 nm) [nm], and the vertical axis represents the liquid crystal layer thickness d0 [μm] of the first liquid crystal cell.

When the maximum value λmax of the transmission peak wavelength of the liquid crystal filter is 800 nm or less, near-infrared light emitted from the labeling agent cannot pass through the liquid crystal filter, making it difficult to detect the concentration of the labeling agent. Therefore, the lower limit of the maximum value λmax is set to 800 nm. Therefore, when the relational expression between Δn (590 nm) and the liquid crystal layer thickness d is obtained from the relation between Δn (590 nm) and d0 in the curve of λmax: 800 nm in FIG. 9, the following expression (3) is obtained.
d = 2 ^m (1.034 × Δn− ^0.90 ) (3)
(However, m = 0, 1, 2, 3, 4, 5)
That is, the optimum liquid crystal layer thickness needs to be larger than d expressed by the equation (3).

On the other hand, when the maximum value λmax of the transmission peak wavelength of the liquid crystal filter is 1400 nm or more, a high voltage of 2 to 3 V must be applied in order to detect near-infrared light having a wavelength of 1200 nm or less, resulting in poor spectral characteristics. It becomes stable. Therefore, the upper limit of the maximum value λmax is set to 1400 nm. Therefore, when the relational expression between Δn (590 nm) and the liquid crystal layer thickness d is obtained from the relation between Δn (590 nm) and d0 in the curve of λmax: 1400 nm in FIG. 9, the following expression (4) is obtained.
d = 2 ^m (2.266 × Δn− ^0.82 ) (4)
(However, m = 0, 1, 2, 3, 4, 5)
That is, the optimal liquid crystal layer thickness needs to be thinner than d expressed by the equation (4).

Therefore, the optimal liquid crystal layer thickness d is calculated from the equations (3) and (4).
2 ^m (1.034 × Δn ^−0.90 ) <d <2 ^m (2.266 × Δn ^−0.82 ) (5)
(However, m = 0, 1, 2, 3, 4, 5)
It becomes.

Basically, it is sufficient to satisfy equation (5), but more desirable conditions are obtained as follows.
When the maximum value λmax of the transmission peak wavelength of the liquid crystal filter is 900 nm or more, the noise component of the near infrared light emitted from the labeling agent can be removed, and the intensity detection becomes easier. Therefore, when the optimum liquid crystal layer thickness d is obtained by the above-described procedure using the curve of λmax: 900 nm in FIG. 9, the following equation (6) is obtained.
d = 2 ^m (1.245 × Δn− ^0.89 ) (6)
(However, m = 0, 1, 2, 3, 4, 5)
That is, the optimum liquid crystal layer thickness needs to be larger than d expressed by the equation (6).

On the other hand, when the maximum value λmax of the transmission peak wavelength is 1300 nm or less, near infrared light having a wavelength of 1200 nm or less can be detected more stably without applying a high voltage. Therefore, when the optimum liquid crystal layer thickness d is obtained by the above-described procedure using the curve of λmax: 1300 nm in FIG. 9, the following equation (7) is obtained.
d = 2 ^m (1.865 × Δn− ^0.83 ) (7)
(However, m = 0, 1, 2, 3, 4, 5)
That is, the optimal liquid crystal layer thickness needs to be thinner than d expressed by the equation (7).

Therefore, the optimum liquid crystal layer thickness d is obtained from the equations (6) and (7):
^{2 m (1.245 × Δn -0.89)} <d <2 m (1.865 × Δn -0.83) ... (8)
(However, m = 0, 1, 2, 3, 4, 5)
It becomes.

  The value of “m” in the above formula is preferably 0, 1, 2, 3, 4, or 5. When the numerical range of the liquid crystal layer thickness d in the above formula is obtained from such a numerical range of “m”, it is approximately several μm to 100 μm. The reason why the above numerical range is preferable is that when the value of “m” exceeds 5, the transmission wavelength region as a bandpass filter becomes too small, the transmittance starts to decrease, and the liquid crystal layer thickness d becomes 100 μm or more. This is because the liquid crystal cell is difficult to manufacture.

[Liquid crystal filter-6]
A sixth configuration example of the liquid crystal filter will be described with reference to FIGS.
FIG. 10 is a perspective view showing the liquid crystal filter of this configuration example in an exploded state. FIG. 11 is a graph showing the relationship between the voltage applied to each liquid crystal cell and the transmission peak wavelength. FIG. 12 is a diagram showing the spectral characteristics of the liquid crystal filter. In FIG. 10, the same components as those in FIG. 3 of the first configuration example are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 10, the liquid crystal filter of this configuration example includes a correction liquid crystal cell 24 in the fourth layer of the liquid crystal filter of the first configuration example. In the correction liquid crystal cell 24, the pair of glass substrates 12 and 13 are in anti-parallel alignment, and the liquid crystal molecules constituting the liquid crystal layer are in homogeneous alignment. The pair of polarizing plates 14 and 15 have their transmission axes orthogonal to each other, and the direction of the transmission axis of one polarizing plate (the lower polarizing plate 15 in FIG. 10) is relative to the orientation direction of one substrate. They are arranged to form an angle of 135 ° ± 5 °. Similarly to the first configuration example, the liquid crystal layer thickness of the first liquid crystal cell 21a is 6.5 μm, the liquid crystal layer thickness of the second liquid crystal cell 21b is 12.9 μm, and the liquid crystal layer thickness of the third liquid crystal cell 21c is 25.8 μm. The liquid crystal layer thickness of the correction liquid crystal cell 24 is 16.1 μm.

According to this configuration example, it is possible to realize a liquid crystal filter having a spectral characteristic shown in FIG. 12 and having a transmission wavelength range of a wavelength of 800 to 1200 nm. Compared with the spectrum of FIG. 6 of the first configuration example, it can be seen that a noise component of 700 nm or less is reduced.
As mentioned above, although the structural example of the liquid crystal filter was shown to [liquid crystal filter-1]-[liquid crystal filter-6], the order which laminates a plurality of sets of liquid crystal cells may be arbitrary.

[Concentration distribution calculation method]
Next, a density calculation method by the DSP 6 will be described.
The DSP 6 reads out the image data for each wavelength stored in the external memory 7 and detects the concentration of the labeling agent from the image data and a previously stored data table. This data table corresponds to a calibration curve, and the light intensity distribution of each pixel constituting the image data is collated with the correlation between the light intensity and the labeling agent concentration in the data table to obtain the concentration of the labeling agent. The correlation between the light intensity and the labeling agent concentration is obtained by a preliminary experiment, and a data table is prepared. Instead of the method using the data table, the multi-variate analysis may be performed based on the light intensity distribution data at each point to obtain the labeling agent concentration. Thereafter, the DSP 6 calculates the concentration of the drug from the concentration of the labeling agent.

When the drug concentration is Cx, the labeling agent concentration is Cm, and the elapsed time after administration is t, the drug concentration Cx can be regarded as a function of the labeling agent concentration Cm and the elapsed time t. That is,
Cx = f (Cm, t) (9)
It is.
Specifically, for example,
Cx = k (t) · Cm + 1 (t) (10)
It becomes. In this case, after the mixture of the labeling agent and the drug is administered to the living body, blood is collected at a plurality of time points, and the correlation between the elapsed time t, the concentration Cm of the labeling agent and the concentration Cx of the drug is examined. Find k (t) and l (t) in the equation. Thereafter, if the concentration of the labeling agent can be determined by the above method, the concentration of the drug can be calculated from the equation (10).

  For example, when a mixture of a labeling agent and a drug is administered to a living body every few hours by intravenous injection, it is estimated that the labeling agent and the drug change in concentration as shown in FIG. 13 at a predetermined position in the living body. That is, when it is desired to control the drug concentration within the concentration control range Cmin to Cmax effective for treatment without causing side effects, the concentration Cm of the labeling agent is obtained by the above method, If the concentration Cx is calculated, the change in the drug concentration Cx in the living body can be measured as shown in FIG. 13, and it can be determined whether or not the drug concentration is within the concentration management range. Similarly, when a mixture of a labeling agent and a drug is orally administered every several hours, a trend as shown in FIG. 14 is shown.

  Therefore, the DSP 6 controls the dosage by the drug administration device 2 based on the calculation result of the drug concentration Cx. For example, assuming that the calculated drug concentration Cx is below the lower limit value Cmin of the concentration management range, the drug administration device such as a drug administration micropump is controlled to increase the dose and administration rate of the drug.

  In the dosing device 1 of the present embodiment, the drug concentration is not calculated only by the light intensity value of the specific wavelength, but is calculated from the light intensity distribution of a predetermined wavelength band such as about 800 to 1200 nm. Therefore, the drug concentration can be calculated with high accuracy. Thus, according to the dosing device of the present embodiment, the drug concentration distribution can be accurately and quickly measured by detecting the emitted light from the living body by a non-invasive method without collecting blood or the like, and the measurement result Based on the above, an appropriate dosage can be administered.

  A medical technique called therapeutic drag monitoring (TDM) is known in which the dosage and dosage are designed so that the effective therapeutic concentration is achieved by measuring the blood drug concentration of each individual patient. The dosing device of this embodiment can measure the drug concentration in real time, so that it is not only a route of administration having a long dosing interval (for example, 3 to 6 hours) such as an internal medicine, but also nasal administration, pulmonary administration, intravenous injection, etc. It can also be used for TDM technology in the fast-acting administration route. In addition, what can be obtained with only one point of concentration data in the vein by the conventional blood sampling method can be obtained as two-dimensional concentration distribution data, and the range of information obtained is widened to greatly increase the measurement accuracy. The range of application will be greatly expanded.

  Furthermore, it is possible to apply the TDM concept even to drugs that have not been measured and administered in the past because it is time-consuming and uneconomical. In this way, the effects of various drugs can be greatly extracted without causing side effects. Therefore, although the pharmacological effect is large, it is easy to use a drug that is difficult to use due to a large side effect and a narrow effective concentration range. In this way, according to the present invention, it is possible to improve the quality of medical care and reduce medical costs, which can greatly contribute to society.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, an example in which a mixture of a labeling agent and a drug is administered to a living body has been described. However, if a drug having a contrast function can be administered to a living body, it is not necessary to use a labeling agent. In this case, if a data table describing the correlation between light intensity and drug concentration is created, the drug concentration distribution can be directly obtained from the data of the light intensity distribution of each pixel on the measurement target using the data table. Can do.

In the above embodiment, an example in which a mixture of one type of labeling agent and a drug is used has been described. However, the labeling agent is not limited to one type, and a mixture of a plurality of types of labeling agents and drugs may be used. good. For example, when two kinds of labeling agents are used, two data tables (calibration data table of light intensity distribution for the first labeling agent-labeling agent concentration data table and light intensity distribution for the second labeling agent-labeling agent concentration data table) Line). When the drug concentration is Cx, the first labeling agent concentration is Cm1, the second labeling agent concentration is Cm2, and the elapsed time after administration is t, the drug concentration Cx is the first labeling agent concentration. It can be grasped as a function of the concentration Cm1, the concentration Cm2 of the second labeling agent, and the elapsed time t. That is,
Cx = f (Cm1, Cm2, t) (11)
It is.

Specifically, for example,
Cx = k (t) · Cm1 + 1 (t) · Cm2 + m (t) (12)
It becomes. In this case, after the mixture of the first and second labeling agents and the drug is administered to the living body, blood is collected at a plurality of time points, the elapsed time t, the concentrations Cm1 and Cm2 of the first and second labeling agents, and the drug concentration The correlation with Cx is examined, and k (t), l (t), and m (t) in equation (12) are obtained from the result. Thereafter, if the concentration of the labeling agent is obtained by the method of the above embodiment, the concentration of the drug can be calculated from the equation (12).

  For example, when a mixture of the first and second labeling agents and the drug is administered to a living body by intravenous injection every several hours, the first and second labeling agents and the drug are shown in FIG. It is estimated that the concentration change as shown in FIG. That is, when it is desired to control the drug concentration within the concentration management range Cmin to Cmax effective for treatment without causing any side effects, the concentration Cm1 and Cm2 of the first and second labeling agents are obtained by the above method. For example, if the drug concentration Cx is calculated from the equation (12), the change in the drug concentration Cx in the living body can be calculated as shown in FIG. 15, and whether or not the drug concentration Cx is within the concentration management range Cmin to Cmax. Can be judged. Similarly, when the mixture of the first and second labeling agents and the drug is orally administered every several hours, the trend shown in FIG. 16 is exhibited.

  For example, it is fully expected that the behavior in the living body such as in which position in the living body is likely to be accumulated differs between the labeling agent and the drug. In consideration of this point, it is possible to calculate a drug concentration in a form closer to the actual situation by calculating the drug concentration from a plurality of types of labeling agent concentrations than calculating the drug concentration from one type of labeling agent concentration.

  Moreover, although FIG. 2 of the said embodiment is drawn with the image which arrange | positions the comparatively large concentration distribution measuring apparatus in the position distant with respect to the biological body, it is a small apparatus which measures only a part of body. Alternatively, for example, a device equipped with a light source, a liquid crystal filter, a CCD, and the like may be directly attached to the skin in the form of a wristwatch.

It is a block diagram of the medication apparatus of the embodiment of the present invention. It is a perspective view which shows the image of the use condition of a medication apparatus. It is a perspective view shown in the state which decomposed | disassembled the liquid crystal filter of the 1st structural example. It is sectional drawing of one liquid crystal cell which comprises a liquid crystal filter. It is a graph which shows the relationship between the voltage applied to each liquid crystal cell, and a transmission peak wavelength. It is a figure which shows the spectral characteristic of a liquid crystal filter. It is a perspective view shown in the state which decomposed | disassembled the liquid crystal filter of the 2nd structural example. It is a figure which shows the spectral characteristic of a liquid crystal filter. It is a graph which shows the relationship between optical anisotropy (DELTA) n and the liquid crystal layer thickness d0 of a 1st liquid crystal cell for every maximum value of the transmission peak wavelength of a liquid crystal filter. It is a perspective view shown in the state which decomposed | disassembled the liquid crystal filter of the 6th structural example. It is a graph which shows the relationship between the voltage applied to each liquid crystal cell, and a transmission peak wavelength. It is a figure which shows the spectral characteristic of a liquid crystal filter. It is a graph which shows the relationship between the label | marker agent density | concentration at the time of administering by intravenous injection, and a chemical | medical agent density | concentration. It is a graph which shows the relationship between the labeling agent density | concentration at the time of performing oral administration, and a chemical | medical agent density | concentration. It is a graph which shows the relationship between the density | concentration of two types of labeling agents at the time of administering by intravenous injection, and a drug concentration. It is a graph which shows the relationship between two types of label | marker density | concentrations in case of oral administration, and a chemical | medical agent density | concentration.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Dosing apparatus, 3 ... Light source, 4 ... Liquid crystal filter (wavelength variable filter), 5 ... Area sensor (light detection means), 6 ... Signal processor (drug concentration calculation means), 7 ... External memory, 21a, 21b, 21c, 21d ... liquid crystal cell, 24 ... liquid crystal cell for correction.

Claims (7)

An apparatus for measuring a concentration distribution of the drug in a living body to which a labeling agent having a contrast function and the drug are administered, and performing a medication based on the measurement result,
A dosing means for dosing the living body;
A light source that irradiates light to a living body to be measured;
When the labeling agent is irradiated with the light from outside the living body, the light emitted from the labeling agent to the outside of the living body is incident, and transmits light in a predetermined wavelength region of the entire wavelength region of the incident light, A tunable filter capable of changing the wavelength range;
Light detecting means for detecting the intensity of light incident through the wavelength tunable filter and obtaining intensity distribution of light emitted from a plurality of positions of the measurement object;
The concentration of the drug administered together with the labeling agent is calculated based on the light intensity distribution at the plurality of positions of the measurement target acquired by the light detection unit, and the dosage by the dosing unit is calculated based on the concentration calculation result of the drug Control means for controlling the amount;
A dosing device comprising: An apparatus for measuring a concentration distribution of the drug in a living body to which a drug having a contrast function is administered, and performing a medication based on the measurement result,
A dosing means for dosing the living body;
A light source that irradiates light to a living body to be measured;
When the light is irradiated to the medicine from outside the living body, light emitted from the medicine to the outside of the living body is incident, and transmits light in a predetermined wavelength region out of the entire wavelength region of the incident light, and the wavelength A tunable filter that can change the frequency range,
Light detecting means for detecting the intensity of light incident through the wavelength tunable filter and obtaining intensity distribution of light emitted from a plurality of positions of the measurement object;
Control means for calculating the concentration of the medicine based on the light intensity distribution at the plurality of positions of the measurement object acquired by the light detection means, and for controlling the dosage by the medication means based on the concentration calculation result of the medicine When,
A dosing device comprising:   The wavelength tunable filter has a plurality of liquid crystal cells each including a pair of polarizers, a liquid crystal layer sandwiched between the pair of polarizers, and an electrode for applying a voltage to the liquid crystal layer. The dosing device according to claim 1 or 2, characterized in that   The administration device according to claim 3, wherein an optical filter for blocking light having a wavelength of 650 nm or less is provided on the incident side of the light detection means. A wavelength tunable filter used in a device for measuring a concentration distribution of the drug in a living body to which a labeling agent having a contrast function and a drug or a drug having a contrast function are administered, and performing administration based on the measurement result,
A plurality of liquid crystal cells each including a pair of polarizers, a liquid crystal layer sandwiched between the pair of polarizers, and an electrode for applying a voltage to the liquid crystal layer;
The transmission axes of the pair of polarizers are parallel to each other;
The liquid crystal layer is one in which liquid crystal molecules are homogeneously oriented,
The angle formed by the transmission axis of the pair of polarizers and the alignment direction of the liquid crystal molecules is 45 ° ± 5 °,
A wavelength tunable filter satisfying the following expression (1), where Δn is an optical anisotropy of the liquid crystal layer with respect to light having a wavelength of 590 nm, and d is a layer thickness of the liquid crystal layer.
2 ^m (1.034 × Δn ^−0.90 ) <d <2 ^m (2.266 × Δn ^−0.82 ) (1)
(However, m = 0, 1, 2, 3, 4, 5) The wavelength tunable according to claim 5, wherein when the optical anisotropy of the liquid crystal layer with respect to light having a wavelength of 590 nm is Δn and the thickness of the liquid crystal layer is d, the following formula (2) is satisfied. filter.
^{2 m (1.245 × Δn -0.89)} <d <2 m (1.865 × Δn -0.83) ... (2)
(However, m = 0, 1, 2, 3, 4, 5)   A pair of polarizers, a liquid crystal layer sandwiched between the pair of polarizers, and an electrode for applying a voltage to the liquid crystal layer, wherein the transmission axes of the pair of polarizers are orthogonal to each other, and the liquid crystal The layer has liquid crystal molecules in which liquid crystal molecules are homogeneously aligned, and has a correction liquid crystal cell in which an angle formed by a transmission axis of the pair of polarizers and an alignment direction of the liquid crystal molecules is 45 ° ± 5 °. The wavelength tunable filter according to claim 5 or 6.

Images