JPH09264845A - Absorptiometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lightly and stably perform measurement even in the light by measuring absorbancy on the basis of electrical electronical modulation in the predetermined frequency of LED light. SOLUTION: A sample soln. is continuously allowed to flow through a tube 1 and a start key is operated to start measurement. An LED 32 flickers in frequency of 20kHz corresponding to the oscillation signal of an oscillation circuit 21 and a part of the light thereof is absorbed by the sample in the tube 1 and only transmitted light arrives at a photodiode 34 along with external light. Only a component with frequency of 20kHz in the detected luminous intensity of the arrival light passes through a BPF 23. The external light component from solar rays or a fluorescent lamp is removed because frequency is different. Then, absorbancy is calculated on the basis of the luminous intensity only of transmitted light. Even if the circumference is bright or dark and light and shade changes, absorbancy can be stably calculated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorptiometer, and more particularly to an absorptiometer capable of easily analyzing coloration, fading, colorimetry, sedimentation, suspension and turbidity even in a bright place.

[0002]

2. Description of the Related Art Conventionally, as shown in the basic block diagram of FIG. 5, an absorptiometer is an optical device that selects a light source such as a halogen lamp and a light of a specific wavelength range from the light from the light source and transmits it. A filter, a diaphragm that irradiates the transmitted light only on the sample at the measurement site, and a photodetector that photoelectrically converts the irradiation light that has arrived through the shutter to detect its intensity,
An amplifier for amplifying the detection signal and a display for displaying the detected / measured light intensity / absorbance are provided.

Further, there is provided a housing 2 which is a dark box for accommodating these optical systems and the like and shielding them from light. In the absorptiometer for continuous measurement, as shown in the schematic cross-sectional view of FIG. 6, a transparent tube 1 penetrating the inside of the housing 2 is arranged so as to pass through the optical axis. The absorbance of the sample is detected in a dark space by pouring the sample solution from the outside.

Further, in an absorptiometer that supports multi-wavelength measurement, a plurality of optical systems and measurement systems are provided, and photometry is performed in parallel with each set. Alternatively, a turret switching mechanism that rotates a circular turret equipped with at least a plurality of interference filters or slides a sliding turret is provided, and photometry is performed in a time division manner.

[0005]

However, in such a conventional absorptiometer, since the Tungstan halogen lamp or the discharge tube is used as the light source, the life of the lamp or the like is short and the high output is stabilized. There are drawbacks such as the need for a power supply. An interference filter or the like is used as the optical filter, but this is expensive. Moreover, the combination of the lamp and the interference filter requires a high-rigidity body because the aperture / slit, the shutter, and the lens system combined with them tend to be complicated and unstable due to the widening of the light source. In particular, when the cell has a curved surface and acts like a lens, design restrictions and difficulties increase. Further, since the heat generated by the lamp is large, there are various inconveniences such as that the heat radiation design is strict and the heat distribution must be stabilized before use.

Further, in order to avoid the influence of ambient light from the sun or fluorescent lamps, photometry is carried out in a dark box, but the sample introduction outlets (2a, 2b), the light source air cooling vents (2c, 2d), etc. It is difficult to completely block light. Further, it is difficult to eliminate stray light from the light source, the optical filter and the like. Inevitably, the housing has high rigidity, and the light shielding mechanism provided therein is complicated. Further, with respect to sample introduction tools such as tubes, cells, plates, etc., it is troublesome to perform operations such as setting and replacement, and there is an inconvenience that the diameter and shape of the tube are restricted.

It is possible to use a semiconductor laser instead of the lamp and the filter, but this involves a so-called mode jump phenomenon in which the wavelength changes irregularly with respect to the driving current, and a resonator for heat generation. There are peculiar phenomena such as frequency fluctuations due to expansion, and fluctuations and fluctuations of oscillation thresholds, which complicates the temperature compensation circuit, the power supply stabilization circuit, and the control circuit, making it difficult to operate stably. Moreover, the usable wavelength range is limited, and even if it can be used, there is a cost difficulty except for a specific one for an optical pickup.

On the other hand, unlike a spectrophotometer for elemental analysis, in the case of an absorptiometer for analyzing coloration, suspension, etc., the absorption sample type is known in advance and its absorption The spectrum width is often somewhat looser than the emission spectrum width of an interference filter or a semiconductor laser. For example, a coloring solution of potassium permanganate contained absorption maximums at 525 nm and 545 nm in its absorption spectrum.
There is a band showing sufficient absorption over a width of 0 nm or more.

In such a case, it is more important that the optical system such as the light source, the driving system and the like operate stably and at high speed than the narrow spectral width of the measurement wavelength. Furthermore, operability and cost are also important. Therefore, instead of this type of light source, etc., a light source with long life, high stability and low cost is adopted, and by making full use of the measurement technique with no or little difficulty due to light shielding, the mechanism / circuit is The challenge is to develop a device that is simple and easy to use without worrying about the surrounding brightness.

Further, provision of a turret switching mechanism for multi-wavelength measurement also requires an extra drive mechanism, control circuit, etc., which becomes a factor of complicating the apparatus and further a factor of cost increase. . Therefore, it is a further problem to devise a device that can stably and easily perform multi-wavelength measurement even with a simple configuration.

The present invention has been made in order to solve such a problem, and an object thereof is to realize an absorptiometer capable of easily and stably measuring absorbance even if it is bright with a simple structure. Another object of the present invention is to realize an absorptiometer having a simple structure, which can easily and stably perform multi-wavelength measurement even if it is bright.

[0012]

Means for Solving the Problems First to third solving means invented to solve such problems are as follows.
The configuration and operation and effect will be described below.

[First Solving Means] The absorptiometer of the first solving means (as described in claim 1 at the time of application) detects the luminous intensity of transmitted light by irradiating the sample with light from a light source. In an absorptiometer for determining the absorbance of the sample based on the detected light intensity, a light emitting diode provided as the light source and having an emission wavelength corresponding to the absorption wavelength range of the sample, and the light from the light emitting diode is optically measured at the time of photometry. An irradiation mechanism for directly irradiating the sample, a drive circuit for supplying a drive current containing an AC component of a predetermined frequency to the light emitting diode, and an extraction and output of the corresponding component of the predetermined frequency from the detected luminous intensity. A filter circuit is provided, and the absorbance of the sample is obtained based on the output of the filter circuit.

Here, "the emission wavelength corresponds to the absorption wavelength region of the sample" means that the peak wavelength in the emission spectrum of the light emitting diode (LED) coincides with the absorption maximum in the absorption spectrum of the sample. It may be surrounded by a plurality of absorption maxima or in the vicinity of these maxima. In addition, "optically directly" means not through an object such as an optical filter that intentionally changes the spectral distribution in the detection wavelength range, and simply protects the device from dirt and damage. The inclusion of a transparent protective film or the like is not excluded. Further, the “predetermined frequency” may be a frequency that is high enough to be discriminated from the frequency of changing sunlight and the frequency of blinking of a fluorescent lamp, but from the viewpoint of high-speed processing, it is several KHz or more, and the circuit is simple. From the standpoint of compatibility, several MHz or less is desirable. The "corresponding component" includes not only narrow band components that are separated and extracted by a bandpass filter, etc., but also harmonics that are separated and extracted by a highpass filter, etc. unless they are confused with the frequency components of external light or separately detected. It may be something like this.

In the absorptiometer of the first means as described above, the sample is placed at a position where the light from the light emitting diode is directly irradiated by the irradiation mechanism at the time of measuring the sample, and the sample is emitted from the LED. Is irradiated with light corresponding to the absorption wavelength range. At this time, the drive circuit supplies a drive current including an AC component of a predetermined frequency to the light emitting diode. Therefore, the intensity of the irradiation light on the sample changes at a predetermined frequency. Then, the intensity of the transmitted light from the LED is detected, which also changes at the same frequency. on the other hand,
The ambient light from the sunlight and the fluorescent lamp changes gently at a frequency lower than that, but as the detected luminosity, all of these lights are collectively detected.

Then, a filter circuit extracts a corresponding component of a predetermined frequency from the detected light intensity, and the absorbance of the sample is obtained based on the corresponding component. At this time, the ambient light has a different frequency and is removed by the filter circuit. As a result, the ambient light from sunlight and fluorescent lamps is LE
Even if it is detected together with the light from D, the absorbance of the sample can be obtained based on only the light of the LED. Therefore, the absorbance can be measured easily and accurately even when the dark box, the light-shielding mechanism, or the like is omitted or extremely simplified, or even under a bright day.

The LED is a light source of a substantially single wavelength having a spread of ± 20 to 30 nm with a peak wavelength as a center, and extends over a wide wavelength range from ultraviolet rays to visible rays to infrared rays. Inexpensive commercial products are supplied. Therefore, it is possible to obtain the measurement light of a desired wavelength without using an interference filter or the like. Moreover, since all the energy of the generated light is effectively used for measurement, there is no wasteful heat generation.

As a result, the problem of heat caused by the halogen lamp or the like and the problem of instability caused by the interference filter or the like are eliminated or greatly suppressed, and the absorbance measurement can be stably performed. Moreover, the lens system and the heat dissipation mechanism are simple, and the rigidity is low. Further, since the LED itself is a small point light source, even if the sample cell has a curved surface, sufficient focusing can be easily performed simply by bringing them close to each other.

Further, the LED has a relatively stable emission wavelength and a long life. Furthermore, the magnitude of the output with respect to the drive current and the light emission range are stable. Therefore, stable light emission can be easily performed by providing a drive current having a simple waveform in which only a sine wave is superimposed.
There are few distortion components such as harmonics. As a result, the drive circuit and the light receiving / detecting circuit can be simple. Moreover, the temperature compensating circuit, the power source stabilizing circuit, and the control circuit can be simple.

Therefore, according to the present invention, it is possible to realize an absorptiometer having a simple structure, which can easily and stably measure the absorbance even if it is bright.

[Second Solving Means] The absorptiometer of the second solving means (as described in claim 2 at the beginning of the application) is the absorptiometer of the first solving means described above. A main body portion housing a drive circuit, a probe portion provided separately from the main body and including at least the irradiation mechanism, and interposed between the main body portion and the probe portion and at least from the drive circuit to the light emitting diode. And a flexible cord for transmitting a drive current.

In the absorptiometer of the second means as described above, the probe section is provided separately from the main body with the flexible cord interposed, and therefore the probe section is used for measuring the absorbance. It can be moved freely. Further, since the drive circuit and the like are housed in the main body and the light emitting diode is supplied with the drive current through the cord, the probe unit is downsized. Therefore, such a probe has almost no restrictions on the place, direction, width, etc. when it is set on a sample tube or the like. Then, instead of setting the tube or the like on the main body, the probe unit is set on the sample tube or the like, whereby the absorbance measurement is performed.

As a result, the trouble of setting a tube or the like on the main body and restrictions are released. Also, it can be easily adapted to a hard tube or a thick tube.
Therefore, the absorbance can be easily measured. In addition,
Even if the probe unit is exposed to external light, the absorbance measurement can be accurately performed by the absorbance measurement based on the electric / electronic modulation of the LED light at the predetermined frequency as described above.

Therefore, according to the present invention, it is possible to realize an absorptiometer having a simple structure, which is capable of stably measuring the absorbance even if it is bright.

[Third Solving Means] The absorptiometer of the third solving means (as described in claim 3 at the beginning of the application) is the absorptiometer of the above first or second solving means. The light emitting diode includes a plurality of LEs that emit light at respective emission wavelengths corresponding to different absorption wavelength ranges of the sample.
The D chip is integrally incorporated, and the driving circuit includes an AC component having a frequency different from the frequency of the AC components included in the other driving currents when driving the light emitting diode. Generate multiple drive currents,
Each driving current is supplied to each of the plurality of LED chips, and the filter circuit discriminates and extracts corresponding components of the plurality of frequencies from the detected luminous intensity. is there.

In the absorptiometer of the third means as described above, a plurality of LED chips which emit light with different emission wavelengths are integrally incorporated, and therefore, in measuring the absorbance, there are a plurality of emission wavelengths. Light is simultaneously applied to the sample at the same measurement site. Moreover, the drive circuit modulates the light of each emission wavelength at a different frequency.
Then, the intensity of the transmitted light is detected by a single light receiver, and the filter circuit discriminates each modulation frequency to extract the luminous intensity of the corresponding component.

By performing frequency modulation / multiplexing based on electrical / electronic processing in this manner, it is possible to detect the luminous intensity separately for each emission wavelength without depending on optical processing such as spectroscopy. it can. Moreover, the absorbance of the sample in different absorption wavelength ranges can be measured in parallel without being affected by external light, that is, ambient light, or being affected by other emission wavelengths. Furthermore, since it is not necessary to provide a light receiver or the like for each absorption wavelength region, the circuit scale can be small.

Thus, even if there is no turret switching mechanism or the like that involves mechanical operation, the absorbance in a plurality of absorption wavelength regions of the subject is measured in parallel based on the drive circuit and the filter circuit that can be simply constructed. be able to.

Therefore, according to the present invention, it is possible to realize an absorptiometer having a simple structure which can easily and stably perform multi-wavelength measurement even if it is bright.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION A mode for carrying out the absorptiometer of the present invention achieved by the first to third means for solving the problems will be described.

[First Embodiment] In the first embodiment of the present invention, an absorptiometer of the first solving means for carrying out the above-mentioned first solving means, In order to measure the absorbance of a sample having a plurality of measurement sites or a sample divided into a plurality of measurement sites, each of the light emitting diodes has an emission wavelength corresponding to the absorption wavelength range of each sample at the plurality of measurement sites. A plurality of light emitting elements are provided, and the light emitting element holding device holds the plurality of light emitting diodes at positions such that the light emitting surfaces of the plurality of light emitting diodes face the plurality of measurement sites placed in the photometric state. A mechanism and a light emitting element switching circuit for sequentially selecting and switching a light emitting diode to which a drive current is to be supplied by the drive circuit from among the plurality of light emitting diodes. Than it is.

In the absorptiometer of the first embodiment as described above, a plurality of light emitting diodes are held by the light emitting element holding mechanism, and at the time of photometry, the light emitting surfaces of the respective light emitting diodes are a plurality of objects of the subject. Oppose each of the measurement sites. Therefore, the light from the light emitting diode is directly applied to the sample at the facing position. In addition, the light emitting element switching circuit sequentially selects and switches the light emitting diode to which the drive current is to be supplied from the plurality of light emitting diodes. And
Light having a wavelength corresponding to the absorption wavelength range of the sample at each measurement site, which is electrically and electronically frequency-modulated, is emitted from the light emitting diode to which the drive current is supplied by the drive circuit. Therefore, even when there are a plurality of light emitting elements, it is possible to perform measurement on the sample at each measurement site without being affected by each other even when exposed to external light or the like.

As a result, it is possible to easily and stably measure the absorbance even when it is bright based on the electrical / electronic frequency modulation of the LED light as described above, and in addition, to move the sample or the like with respect to the optical path. Even if neither the moving mechanism nor the XY scanning mechanism for swinging the optical path with a galvanometer is used, it is possible to measure a plurality of measurement sites of the subject based on electronic light emitting element switching. The electronic switching circuit is faster and more reliable than the moving / scanning mechanism involving mechanical operation, and has a simple structure.

Therefore, according to the present invention, it is possible to realize an absorptiometer having a simple structure which can easily and stably perform multipoint measurement even if it is bright.

[Second Embodiment] In a second embodiment of the present invention, the absorptiometer of the first embodiment described above is used, in which the plurality of measurement sites of the subject are matrix-shaped. The plurality of light-emitting diodes (or the plurality of light-emitting diodes and a plurality of light-receiving elements (such as photodiodes and phototransistors) paired with the light-emitting diodes corresponding to the light-emitting elements arranged in a line (or in a line) ) Are arranged in a matrix (or in a line) in the light emitting element holding mechanism (or the light emitting element holding mechanism and the light receiving element holding mechanism paired therewith).

[0036]

【Example】

[First Embodiment] A specific configuration of the first embodiment of the absorptiometer of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a main part thereof, and FIG. 2 is an outline view of a sandwiching body as a probe section thereof.

This absorptiometer has an LED 3 as a light source.
The light from the transparent tube 1 is radiated to the sample of the transparent tube 1, the amount of transmitted light is detected by the photodiode 34, and the absorbance of the sample is continuously measured.
In order to easily perform photometry with the device placed outside the device, the main body 20, the sandwiching body 30 as a probe unit to which the pair of LEDs 32 and the photodiode 34 are mounted,
Flexible cords 31, 33 interposed between these
It is composed of

For example, when the sample is a colored solution of potassium permanganate, the LED 32 is made of AlP whose emission wavelength peak is close to 535 nm, and the emission wavelength is in the absorption wavelength range of the sample in the tube 1. It corresponds to. The tube 1 is transparent in the wavelength range including this emission wavelength, and the photodiode 34 can detect light in the wavelength range including this emission wavelength.

In the main body 20, an oscillation circuit 21 for driving the LED 32, an amplifier 22 for detecting light intensity using a photodiode 34, a bandpass filter 23, and a detection circuit 24.
And an amplifier 25 are stored, and a display 26
Is also attached.

The oscillation circuit 21 has an sine wave as an oscillating waveform, an oscillating frequency of 20 KHz, and a peak voltage of 0.7 V.
It is an oscillating circuit of ˜5 V, and its voltage oscillation signal is converted into a current signal by a buffer amplifier (not shown), passed through a current limiting resistor, and then sent to the LED 32 via the code 31. As a result, this absorptiometer includes a drive circuit that supplies a drive current containing an AC component of a predetermined frequency to the light emitting diode, and a flexible cord that transmits the drive current from the drive circuit to the light emitting diode. It has become a thing.

The band-pass filter 23 is a filter that passes only a narrow band component having a center frequency of 20 KHz. The detection system around the filter 23 is
A light intensity signal photoelectrically converted and detected by the photodiode 34 is input to the amplifier 22 via the code 33,
After amplification by the amplifier 22, only the 20 KHz component is converted by the bandpass filter 23, envelope detection is further performed by the detection circuit 24, and finally amplified by the amplifier 25, and then displayed on the display 26. Although illustration is omitted, before or after the amplifier 25,
There is also provided computing means for calculating the absorbance and its secondary information according to the type of analysis such as coloration, fading, colorimetry, sedimentation, suspension, and turbidity. As a result, this absorptiometer is provided with a filter circuit that extracts and outputs a corresponding component of a predetermined frequency from the detected light intensity, and obtains the absorbance of the sample based on the output of this filter circuit.

The holding body 30 has a notch, and the LED 32 is inserted into the perforation of the lower portion of the notch with the light emitting surface of the LED 32 facing the notch side, and also the notch has a notch and the photodiode 34 has the light receiving surface. The sandwiching pieces 36 inserted into the perforations of the cutout lower portion toward the cutout side, and one end connected to the sandwiching piece 35 so that a sandwiching force is generated when the tube 1 is sandwiched in each cutout, and the other end In order to adjust the distance between the spring 37 connected to the sandwiching piece 36 and the sandwiching pieces 35, 36 so that a parallel state can be ensured, the sandwiching piece 36 is screwed and penetrated, and the tip end of the sandwiching piece 3 is formed.
5 and the screw 38 that abuts on 5. And the LED 32
The light emitted from the light source passes through the tube 1 and the sample and reaches the photodiode 34.

The holding body 30 provided separately from the main body 20 with the cords 31 and 32 interposed in this way includes an irradiation mechanism for optically irradiating the light from the light emitting diode directly to the sample at the time of photometry. Has become. In addition, LE
D32 and the photodiode 34 are provided with screws (not shown) so that the light receiving surface of the photodiode 34 can be aligned with the focal position of the LED light even if the focal position of the LED light changes depending on the diameter of the tube 1 or the refractive index of the sample. The insertion position in the hole can be adjusted by operation.

The operation and use mode of the absorptiometer having such a configuration will be described.

First, the clamping pieces 35 and 36 are opened, the tube 1 is clamped between these notches, and the screw 38 is clamped while the tube 1 is clamped by the pulling force of the spring 37.
To rotate the clamping pieces 35 and 36 in parallel. Then, the main body 20 is turned on. Then, light is emitted from the LED 32 toward the photodiode 34. Therefore, in the case of visible light, it is based on visual inspection or the like, and in the case of invisible light, the display 26
The position and the like of the photodiode 34 are adjusted so that the photodiode 34 can sufficiently receive the irradiation light based on the display value and the like. Now you are ready for continuous measurement.
No need to turn off lights or close doors.

Next, the sample solution is continuously flown into the tube 1. In this state, the start key or the like of the device is operated to cause the device to start measurement. Then, the LED 32 blinks at a frequency of 20 KHz according to the oscillation signal of the oscillator circuit 21, the light is partly absorbed by the sample of the tube 1, and only the transmitted light reaches the photodiode 34 together with the external light.

The frequency of the detected light intensity of the reaching light is 2
Only the 0 KHz component passes through the bandpass filter 23. The external light components from the sunlight and the fluorescent lamp have different frequencies and are removed. Alternatively, even if the frequency component is present, it is extremely small, and is reduced to a negligible level. Therefore, the absorbance is calculated based on the luminous intensity of only the transmitted light.
Absorbance can be stably obtained regardless of whether the surroundings are bright, dark or light. The resulting values and graphs are displayed on the display 2.
6 is displayed.

Thus, while the sample is flowing, the absorbance of the sample is continuously measured and the state change of the sample solution is displayed in real time. Therefore, by using this absorptiometer, the absorbance of the sample liquid flowing through the tube 1 can be easily and stably measured even if it is bright.

[Second Embodiment] The second embodiment of the absorptiometer of the present invention.
A specific configuration of the embodiment will be described with reference to the drawings. FIG. 3 is a block diagram showing the configuration of the main part, and FIG. 4 is a partial cross-sectional view showing the structure of the LED. The absorptiometer of the second embodiment is a partially duplicated version of the absorptiometer of the first embodiment, and therefore the differences will be mainly described below.

The basic difference is that the LED 32 shown in FIG.
The alternative LED is capable of emitting at two different wavelengths. Therefore, the LED is configured by embedding two LED chips 32a and 32b having different emission wavelengths in one element (see FIG. 4). The material of each chip is selected so that the respective emission wavelengths correspond to the two kinds of absorption wavelength regions of the sample. Specifically, deoxyhemoglobin in a deoxygenated state absorbs light having a wavelength of 555 nm, while oxyhemoglobin in an oxygen-bound state has a wavelength of 57 nm.
In order to measure the oxygen binding rate of hemoglobin based on the absorption of light of 7 nm, the LED chip 32a is a GaP chip having an emission wavelength peak at 555 nm, and the LED chip 32b is an emission wavelength peak of 574n.
m is an InGaAlP / GaAs chip.

On the driving side of the LED, the oscillation circuit 21
Of the LED chip 3
A frequency divider circuit 210 is provided for sending to the current limiting resistor 2b. As a result, the LED chip 32a is modulated and driven at a frequency of 20 KHz as in the first embodiment.
The ED chip 32b is modulated and driven at a frequency of 10 KHz. That is, the drive circuit including the oscillator circuit 21 is
When driving the light emitting diode, a plurality of drive currents containing an AC component having a frequency different from the frequency of the AC component contained in the other drive currents are generated, and the respective drive currents are respectively supplied to the plurality of LED chips 32a, 32b. Is to be supplied to.

Further, on the light intensity detecting side, a bandpass filter 230 which receives the output of the amplifier 22 and passes the 10 KHz component, and a detection circuit 2 which envelope-detects the output of the bandpass filter 230.
40 is provided in parallel with the bandpass filter 23 and the detection circuit 24. As a result, the LED chip 32
The 20 KHz component corresponding to the transmitted light from a is separated and extracted by the bandpass filter 23, while the 10 KHz component corresponding to the transmitted light from the LED chip 32 b is separated and extracted by the bandpass filter 230. That is, these filter circuits discriminate and extract corresponding components of a plurality of frequencies from the detected light intensity signal.

Then, the arithmetic circuit 250 provided subsequent to the detection circuits 24 and 240 calculates the ratio of the 20 KHz component and the 10 KHz component included in the detected light intensity signal, and the calculated result is displayed on the display unit 26. It is supposed to be displayed. By adopting such a configuration, since the photodiode 34 and the like are commonly used in this absorptiometer, compared to the case where a system for wavelength 555 nm and a system for wavelength 574 nm are provided in duplicate, they are small-scale and simple. It has become.

Using such an absorptiometer, the tube 1
When the absorbance is measured while flowing blood through the LED chip 32a, the light emitted from the LED chip 32a blinks at a frequency of 20 KHz and is partially absorbed by the deoxyhemoglobin in the deoxygenated state in the tube 1, and then the photodiode 34,
It is detected by the system of the amplifier 22, the bandpass filter 23, and the detection circuit 24.

On the other hand, in parallel with this, the LED chip 32b is provided.
The light emitted from the flicker at a frequency of 10 KHz is partially absorbed by the oxygen-bonded oxyhemoglobin in the tube 1 and then detected by the system of the photodiode 34, the amplifier 22, the bandpass filter 230, and the detection circuit 240. To be done. Then, the ratio of the absorbances obtained by both systems, that is, the ratio of deoxyhemoglobin and oxyhemoglobin is calculated by the calculation circuit 250 and displayed on the display 26.

In this way, the blood oxygen concentration of the observer during dialysis or surgery can be monitored in real time. Moreover, it can be easily performed without modification of the dialysis machine or the like.

[0057]

As is apparent from the above description, in the absorptiometer according to the first solution of the present invention, the absorbance is measured based on the electrical / electronic modulation of the LED light at a predetermined frequency. By doing so, even if external light is mixed, L
The absorbance is calculated based on only the ED light. Therefore, there is an advantageous effect that it is possible to realize an absorptiometer having a simple configuration, which can easily and stably measure the absorbance even if it is bright.

In the absorptiometer according to the second solution of the present invention, the absorbance is measured based on the electrical / electronic modulation of the LED light at a predetermined frequency, and the probe for detecting the luminosity is obtained. By making the part movable, the trouble of setting tubes etc. in the main body and the restrictions are released. Therefore, there is an advantageous effect that it is possible to realize an absorptiometer having a simple structure, which can perform stable and stable absorbance measurement even if it is bright.

Further, in the absorptiometer according to the third means of solving the problems of the present invention, frequency modulation and multiplexing are performed based on electrical / electronic processing so that optical processing such as spectroscopy does not occur. In addition, it is possible to measure the absorbances of the samples in different absorption wavelength ranges in parallel without being affected by external light or the like, by distinguishing each of the plurality of emission wavelengths. Therefore, there is an advantageous effect that it is possible to realize an absorptiometer having a simple configuration, which can easily and stably perform multi-wavelength measurement even if it is bright.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a main part of a first embodiment of an absorptiometer of the present invention.

FIG. 2 is an outline view of the holding body.

FIG. 3 is a block diagram showing a configuration of a main part of a second embodiment of the absorptiometer of the present invention.

FIG. 4 is a partial cross-sectional view showing the structure of the LED.

FIG. 5 is a block diagram of a conventional absorptiometer.

FIG. 6 is a schematic sectional view of a conventional absorptiometer.

[Explanation of symbols]

1 tube (sample container; measurement site; subject) 2 housing (body; dark box) 20 body 21 oscillation circuit 22, 25 amplifier 23 bandpass filter (BPF) 24 detection circuit 26 indicator 30 sandwiching body (probe; probe part) ; Probe section; separate body 31, 33 Code 32 LED (light emitting diode; light emitting element; light emitting body; light source) 34 Photodiode (light receiving element; light receiver; detection element) 35, 36 Clamping piece 37 Spring 38 Screw 210 minutes Circular circuit 230 Bandpass filter (BPF) 240 Detection circuit 250 Operation circuit 32a, 32b LED chip

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kunihiko Honda 1-1-1, Tanikaga-cho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd.

Claims (3)

[Claims] 1. An absorptiometer which irradiates a sample with light from a light source to detect the luminous intensity of transmitted light and obtains the absorbance of the sample based on the detected luminous intensity. A light emitting diode corresponding to the absorption wavelength region, an irradiation mechanism for optically directly irradiating the light from the light emitting diode to the sample at the time of photometry, and a drive current containing an alternating component of a predetermined frequency are supplied to the light emitting diode. An absorptiometer, comprising: a drive circuit for driving the filter; and a filter circuit for extracting and outputting the corresponding component of the predetermined frequency from the detected light intensity, and determining the absorbance of the sample based on the output of the filter circuit. 2. A main body section accommodating the drive circuit, a probe section provided separately from the main body and including at least the irradiation mechanism, and at least the drive circuit interposed between the main body section and the probe section. The absorptiometer according to claim 1, further comprising a flexible cord for transmitting a drive current from the light emitting diode to the light emitting diode. 3. The light emitting diode is one in which a plurality of LED chips that emit light at respective emission wavelengths corresponding to different absorption wavelength ranges of the sample are integrally incorporated, and the drive circuit is configured to emit the light emission. When driving the diode, a plurality of drive currents containing alternating current components having frequencies different from the frequencies of the alternating current components included in the other drive currents are generated, and the respective drive currents are supplied to the respective LED chips. The absorptiometer according to claim 1 or 2, wherein the filter circuit discriminates and extracts the corresponding components of the plurality of frequencies from the detected light intensity.