JP2007024684A - Automatic analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic analyzer capable of calculating absorbance of high resolving power in a short time by a simple constitution. <P>SOLUTION: The automatic analyzer 1 is constituted so as to irradiate a liquid 7 with light to calculate the optical characteristics of the liquid 7 and has a light source part 2 for emitting light changed in wavelength with the elapse of time, a detection part 3 for detecting the light emitted from the light source part 2 and transmitted through the liquid 7 held to a cuvette 5 and an absorbance operating part 41 for operating the optical characteristics of the liquid 7 by utilizing the quantity of light detected in the detection part 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an automatic analyzer that irradiates a liquid with light and calculates the absorbance of the liquid based on absorbed light absorbed by the liquid and non-absorbed light not absorbed.

  Conventionally, an automatic analyzer that analyzes a sample by mixing and stirring a sample such as blood and urine and a reagent in a container (cuvette), irradiating light of a predetermined wavelength emitted from a light source, and measuring the absorbance of this light It has been known. For example, there is disclosed a technique for performing high-resolution absorbance measurement by changing the amount of transmitted light from an integral type to a successive approximation type and increasing the number of measurements (Patent Document 1).

Japanese Patent Laid-Open No. 9-80055

  In recent years, the cuvette has been downsized to analyze a large number of specimens. When the cuvette is downsized, the optical path length through which light passes through the cuvette decreases, the light amount difference between incident light and transmitted light becomes weak, and absorbance measurement cannot be performed. As described above, the conventional measurement circuit cannot measure the absorbance, and there is a problem that an expensive high-resolution measurement circuit is required.

  For example, when the optical path length is 10 mm and the incident light voltage is 2 V, the measurement resolution needs to be 460 μV in order to make the absorbance resolution 1 / 10,000. When the measurement circuit voltage is ± 10 V and a 16-bit A / D converter is used, the measurement resolution is 305 μV, so measurement is possible. However, when the optical path length is 1 mm, the required measurement resolution is 46 μV, and the measurement circuit does not have enough measurement resolution, so the absorbance resolution cannot be reduced to 1 / 10,000.

  The present invention has been made in view of the above, and an object thereof is to provide an automatic analyzer capable of calculating absorbance without using a high-resolution measurement circuit.

  In order to achieve the above object, an automatic analyzer according to claim 1 emits light whose wavelength changes over time in an automatic analyzer that irradiates a liquid with light and calculates the optical characteristics of the liquid. A light source unit, a detection unit that detects light emitted from the light source unit and transmitted through the liquid held in a container, and an optical component of the liquid using the amount of light detected by the detection unit. And an arithmetic means for calculating the target characteristic.

  In the automatic analyzer according to claim 2, in the above invention, the light source unit includes at least a first wavelength at which the liquid has absorption and a second wavelength at which the liquid has no absorption. It is characterized by emitting light whose wavelength changes.

  Further, in the automatic analyzer according to claim 3, in the above invention, the light source unit includes: a light source that emits light including light of the first wavelength and light of the second wavelength; and the light source. Wavelength selection means for selecting the wavelength of the emitted light and emitting the light.

  The automatic analyzer according to claim 4 is characterized in that, in the above invention, the wavelength selecting means is disposed between the light source and the container, or between the container and the detection unit. To do.

  The automatic analyzer according to claim 5 is characterized in that, in the above invention, the wavelength selecting means is an acousto-optic element.

  In the automatic analyzer according to claim 6, in the above invention, the light source unit includes a first light source that emits light of the first wavelength and a second light source that emits light of the second wavelength. And a light source.

  According to a seventh aspect of the present invention, in the above invention, in the above invention, the detection unit receives a light emitted from the light source and transmitted through the container, and a light receiving element that outputs a signal corresponding to the received light. And amplifying means for amplifying the AC component of the signal output from the light receiving element at the first wavelength and the second wavelength.

  The automatic analyzer according to claim 8 is characterized in that, in the above invention, the calculation means calculates the absorbance of the liquid based on the alternating current component amplified by the amplification means.

  In the automatic analyzer according to the present invention, the wavelength of light applied to the liquid is changed with the passage of time, so that the amount of change in the amount of light at each wavelength can be amplified. Furthermore, since the amount of change in the amount of light can be amplified, the absorbance can be calculated even when the amount of change in the amount of light is small.

  Exemplary embodiments of an automatic analyzer according to the present invention will be described below in detail with reference to the accompanying drawings.

(Embodiment)
FIG. 1 is a block diagram showing a schematic configuration of an automatic analyzer 1 according to the present invention. As shown in FIG. 1, the automatic analyzer 1 includes a light source unit 2 that emits light, a detection unit 3 that detects transmitted light, a light source unit 2 and a detection unit 3, and a control unit that calculates absorbance. 4, a cuvette 5 that contains the liquid 7, and a cuvette holder 6 that holds the cuvette 5.

  The light source unit 2 includes a light source 20 that emits light and an acoustooptic element (AOTF) 21 that selects a wavelength of the light emitted from the light source 20. The detection unit 3 receives the slit 30, the light that has passed through the slit 30, outputs a current corresponding to the received light amount, and IV conversion that converts the current output from the light receiving element 31 into a voltage. 32, a smoothing unit 33 that smoothes the voltage output from the IV conversion unit 32, an A / D conversion unit 35a that converts the smoothed voltage output from the smoothing unit 33 into a digital value, and I− The AC amplifier 34 amplifies the AC component of the voltage output from the V converter 32 at a predetermined magnification, and the A / D converter 35 b converts the voltage amplified by the AC amplifier 34 into a digital value. The control unit 4 includes an AOTF control unit 42 that controls the AOTF 21, an amplification control unit 40 that controls the AC amplification unit 34, and an absorbance calculation unit 41 that calculates the absorbance of the liquid 7.

  Here, an operation in which the automatic analyzer 1 calculates the absorbance of the liquid 7 will be described. First, the control unit 4 outputs a control signal S1 to the light source 20 to cause the light source 20 to emit light, and outputs a control signal S2 to the AOTF 21 so that the AOTF 21 emits light of a predetermined wavelength.

  FIG. 2 is a schematic diagram showing a temporal change in the wavelength of light emitted from the AOTF 21. As shown in FIG. 2, the AOTF 21 changes the wavelength of light to be selected with time. At time t0, the wavelength λ1 that is the wavelength that the liquid 7 has absorption is selected, and at time t1, the wavelength λ2 that is the wavelength that the liquid 7 does not absorb is selected. Note that the light intensity is controlled to be the same even if the wavelength of the light emitted from the AOTF 21 is different. Alternatively, the spectral characteristics of the light source may be stored in advance and correction may be added later.

  Light emitted from the AOTF 21 passes through the liquid 7 accommodated in the cuvette 5, sequentially passes through the cuvette holder 6 and the slit 30, and is received by the light receiving element 31. The light receiving element 31 outputs a current corresponding to the intensity of the received light, the IV conversion unit 32 converts the voltage into a voltage corresponding to the current, and outputs this voltage to the smoothing unit 33 and the AC amplification unit 34. To do.

  FIG. 3 is a schematic diagram illustrating a time change of the voltage output from the IV conversion unit 32. As illustrated in FIG. 3, the IV conversion unit 32 outputs the voltage V2 at time t0 and outputs the voltage V1 at time t1. The IV conversion unit 32 outputs the voltages V <b> 2 to V <b> 1 to the smoothing unit 33 and the AC amplification unit 34 in response to the time change (λ <b> 1 to λ <b> 2) of the wavelength of the light emitted from the AOTF 21.

  The smoothing unit 33 calculates an average value of the voltages V1 to V2 output from the IV conversion unit 32 and outputs the average value to the A / D conversion unit 35a. FIG. 4 is a schematic diagram illustrating the voltage output from the smoothing unit 33. As illustrated in FIG. 4, the smoothing unit 33 outputs an average voltage value Vdc = (V1 + V2) / 2 of the voltages V1 to V2. The A / D conversion unit 35 a converts the input analog value into a digital value, and outputs the smoothed signal S 4 to the control unit 4.

  On the other hand, the AC amplifying unit 34 amplifies only the AC part of the voltages V1 to V2 output from the IV conversion unit 32 according to the amplification signal S3, and outputs the amplified signal to the A / D conversion unit 35b. FIG. 5 is a schematic diagram showing the voltage output from the AC amplifier 34. As shown in FIG. 5, the AC amplifier 34 outputs an AC voltage (+ Vac / 2 to −Vac / 2) obtained by amplifying only the AC part shown in FIG. The A / D conversion unit 35 b converts the input analog value into a digital value, and outputs an AC signal S <b> 5 to the control unit 4.

Here, a method in which the absorbance calculation unit 41 of the control unit 4 calculates the absorbance will be described. In general, the absorbance Va of the liquid 7 is obtained by the following equation (1) when the incident light amount V ₀ and the transmitted light amount V _X are used.
Va = log (V _O / V _X ) (1)
By the way, the incident light quantity V _O corresponds to the voltage (Vdc + Vac / 2A) when the light of wavelength λ2 is emitted, and the transmitted light quantity V _X is the voltage (Vdc−Vac /) when the light of wavelength λ1 is emitted. 2A). Therefore, the expression (1) expressed by the amount of light becomes the expression (2) expressed by the voltage.
Va = log (Vdc + Vac / 2A) / (Vdc−Vac / 2A) (2)

  The absorbance calculation unit 41 calculates an average voltage: Vdc based on the smooth signal S4, an AC voltage: ± Vac based on the AC signal S5, and an amplification factor: A based on the amplified signal S3 in the formula (2). The absorbance Va can be calculated by substituting.

  That is, when the cuvette 5 is downsized and the light amount difference between the incident light and the transmitted light is weak, the difference between the voltage corresponding to the light amount of the incident light and the voltage corresponding to the light amount of the transmitted light is expressed by the A / D conversion unit 35b. The absorbance is calculated by amplifying the voltage to fall within the resolution range.

  In this embodiment, the AOTF 21 selects and emits light having a wavelength that the liquid 7 does not absorb and light having a wavelength that the liquid 7 does not absorb, so that the AC amplifying unit 34 outputs the light emitted from the light source 20. The change at each wavelength can be amplified to a value that can be converted by the A / D converter 35b. Therefore, the absorbance can be calculated even when the change in the amount of light is small.

(Modification 1)
Next, a first modification of the embodiment according to the present invention will be described. In the embodiment, the AOTF 21 is disposed between the light source 20 and the cuvette 5. However, in the first modification, the AOTF 21 is disposed between the cuvette 5 and the light receiving element 31.

  FIG. 6 is a block diagram showing a schematic configuration of an automatic analyzer 1A which is the first modification. As shown in FIG. 6, the light source unit 2 is replaced with a light source unit 2A, and the detection unit 3 is replaced with a detection unit 3A. Other configurations are the same as those of the automatic analyzer 1 described in the embodiment, and the same components are denoted by the same reference numerals.

  The light source unit 2A includes a light source 20 and an AOTF 21, and drives and lights light according to a control signal S1. The drive-lighted light passes through the liquid 7 stored in the cuvette 5 and enters the AOTF 21. The AOTF 21 is controlled by the AOTF control unit 42 and emits light having a wavelength that is absorbed by the liquid 7 and light having a wavelength that is not absorbed by the liquid 7.

  The transmitted light is converted into a voltage via the light receiving element 31 and the IV conversion unit 32 and input to the smoothing unit 33 and the AC amplification unit 34. The smoothing unit 33 outputs a voltage corresponding to the average value of the transmitted light to the control unit 4 via the A / D conversion unit 35a, and outputs a smoothing signal S4. The AC amplifier 34 amplifies the AC component of the transmitted light and outputs an AC signal S5 to the controller 4 via the A / D converter 35b. The control unit 4 calculates the absorbance Va based on the smooth signal S4 and the AC signal S5.

(Modification 2)
Next, a second modification of this embodiment will be described. In the embodiment, the wavelength is selected using the AOTF 21. However, in the second modification, both the light source that emits monochromatic light with the wavelength λ2 and the light source that emits monochromatic light with the wavelength λ1 are provided in place of the AOTF21. The device is simplified.

  FIG. 7 is a block diagram showing a schematic configuration of an automatic analyzer 1B which is the second modification. As shown in FIG. 7, the light source unit 2 shown in the embodiment is replaced with a light source unit 2B, and the control unit 4 is replaced with a control unit 4B. Other configurations are the same as those of the automatic analyzer 1 described in the embodiment, and the same components are denoted by the same reference numerals.

  The light source unit 2B includes a light source 20A that emits light having a wavelength λ1 and a light source 20B that emits light having a wavelength λ2. In addition, the control unit 4B includes a light source control unit 43, and controls lighting of the light sources 20A and 20B by a control signal S5. The light sources 20A and 20B can be realized by LEDs or the like.

  The configuration of the light source unit 2B can be simplified and made inexpensive. In the second modification, the light source unit 2B includes the two light sources 20A and 20B. However, the light source unit 2B may include three or more light sources according to the number of absorption wavelengths of the liquid 7.

It is a block diagram which shows schematic structure of the automatic analyzer concerning embodiment of this invention. It is a schematic diagram which shows the time-dependent change of the incident light which injects into the cuvette concerning embodiment of this invention. It is a schematic diagram which shows the time-dependent change of the voltage which the IV conversion part concerning embodiment of this invention outputs. It is a schematic diagram which shows the time-dependent change of the smoothing voltage which the smoothing part concerning embodiment of this invention outputs. It is a schematic diagram which shows the time-dependent change of the alternating voltage which the alternating current amplifier concerning embodiment of this invention outputs. It is a block diagram which shows schematic structure of the automatic analyzer which is the modification 1 of embodiment of this invention. It is a block diagram which shows schematic structure of the automatic analyzer which is the modification 2 of embodiment of this invention.

Explanation of symbols

1, 1A, 1B Automatic analyzer 2, 2A, 2B Light source unit 3, 3A Detection unit 4, 4B Control unit 5 Cuvette 6 Cuvette holder 7 Liquid 20, 20A, 20B Light source 21 AOTF
DESCRIPTION OF SYMBOLS 30 Slit 31 Light receiving element 32 IV conversion part 33 Smoothing part 34 AC amplification part 35a, 35b A / D conversion part 40 Amplification control part 41 Absorbance calculating part 42 AOTF control part 43 Light source control part

Claims (8)

In an automatic analyzer that irradiates a liquid with light and calculates the optical characteristics of the liquid,
A light source unit that emits light whose wavelength changes over time;
A detection unit that detects light emitted from the light source unit and transmitted through the liquid held in a container;
A computing means for computing the optical characteristics of the liquid using the amount of light detected by the detection unit;
The automatic analyzer characterized by having.   The light source unit emits light whose wavelength changes in a range including at least a first wavelength at which the liquid has absorption and a second wavelength at which the liquid does not absorb. The automatic analyzer described. The light source unit is
A light source that emits light including light of the first wavelength and light of the second wavelength;
Wavelength selecting means for selecting the wavelength of the light emitted from the light source and emitting the light;
The automatic analyzer according to claim 2, further comprising:   The automatic analyzer according to claim 3, wherein the wavelength selection unit is disposed between the light source and the container, or between the container and the detection unit.   The automatic analyzer according to claim 3, wherein the wavelength selection unit is an acousto-optic element. The light source unit is
A first light source that emits light of the first wavelength;
A second light source that emits light of the second wavelength;
The automatic analyzer according to claim 2, further comprising: The detector is
A light receiving element that receives light emitted from the light source and transmitted through the container, and outputs a signal corresponding to the received light;
Amplifying means for amplifying an alternating current component of the signal output from the light receiving element at the first wavelength and the second wavelength;
The automatic analyzer according to claim 2, further comprising:   8. The automatic analyzer according to claim 7, wherein the calculating means calculates the absorbance of the liquid based on the alternating current component amplified by the amplifying means.

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