JP2008051822A - Chemical analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the amounts of a sample to be tested and a reagent to trace amounts, and to improve measurement accuracy, in a chemical analyzer. <P>SOLUTION: In the chemical analyzer that has the light from a light source 21 made incident on a reaction tube 4 containing a mixed liquid of the sample to be tested and the reagent, the light transmitted through the reaction tube 4 is separated into a spectrum, is detected, and performs measurements on prescribed items on the basis of detection results, the chemical analyzer is provided with both an optical lens 24 that is arranged between the light source 21 and the reaction tube 4, and a slit 22 arranged between the light source 21 and the optical lens 24, at a position separated from the optical lens 24 by its focal distance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a chemical analyzer that analyzes components contained in a liquid, and more particularly to a chemical analyzer that automatically analyzes chemical components contained in human blood, urine, and the like.

  The automatic chemical analyzer dispenses a predetermined amount of the sample to be tested and the reagent corresponding to the measurement item into the reaction tube, reacts at a constant temperature after stirring and mixing, and measures the change in color tone caused by this reaction. The concentration / activity of the analyte or enzyme in the test sample is measured.

  The color tone is measured by irradiating light from a light source onto a reaction liquid in which a test sample and a reagent in a reaction tube are mixed, and then splitting the light obtained through the reaction liquid and receiving it with a photodetector. The change of the specific wavelength component absorbed in is detected. At this time, the magnitude of the light beam incident on the reaction tube from the light source is set to be smaller than the height of the reaction solution in the reaction tube. That is, the filament image of the light source irradiated to the reaction tube is set to be smaller than the height of the reaction solution in the reaction tube.

  On the other hand, in order to keep the running cost of the automatic chemical analyzer low, it is desired to reduce the amount of reagent dispensed into the reaction tube. In order to reduce the amount of this reagent, there are conventionally the following methods.

  First, the first method is to reduce the volume of the reaction tube. For example, when 150 μL of reagent is dispensed into a reaction tube having a bottom area of 5 mm × 6 mm, the liquid height is 5 mm, but when the bottom area of the reaction tube is 4 mm × 5 mm, 150 μL of reagent is dispensed. A liquid height of 5 mm can be obtained. As described above, in order to obtain an accurate measurement result, it is necessary to make the filament image of the light source irradiated to the reaction tube smaller than the height of the reaction solution in the reaction tube, but to reduce the bottom area of the reaction tube. Thus, the height of the reaction solution can be made sufficiently larger than the filament image of the light source irradiated to the reaction tube, an accurate measurement result can be obtained, and the required amount of reagent can be reduced. Is possible. However, since this method reduces the bottom area of the reaction tube, operations such as dispensing of a test sample or reagent, stirring, photometry, and washing and drying of the reaction tube are restricted. Further, there is a problem that the optical path length for photometry is shortened and the measurement accuracy is lowered.

  A second method is to reduce the light incident on the reaction tube. In order to reduce the amount of reagent without changing the volume of the reaction tube, it is necessary to reduce the filament image of the light source irradiated to the reaction tube as the liquid height in the reaction tube decreases. For this reason, as the second method, a small filament lamp is used as a light source, or a method of providing a light shielding plate for restricting the transmission of light rays on either the front or back of the reaction tube through which the light rays pass (for example, There is a method in which the filament image projected by tilting the lamp filament is reduced (see, for example, Patent Document 2). However, in the method using a small filament lamp, it is necessary to make the winding very dense in order to obtain a desired luminance, and it is difficult to obtain a desired life. In addition, in the method of providing a light shielding plate, the light wave characteristic causes diffraction of light near the boundary between the light transmitting part and the light shielding part, so that a sufficient light shielding effect cannot be obtained, and the light incident on the reaction tube is made sufficiently small. It ’s difficult. Furthermore, the method of tilting the lamp filament suppresses the amount of light applied to the test sample, and the light source is dispersed in the direction of the optical axis, resulting in blurring of the light beam at the focal position.

  In the measurement of the color tone, a diffraction grating and a light detection element array are generally used to split light transmitted through the reaction solution and receive the light with a photodetector. In this case, the diffraction grating and the light detection element are used. If multiple reflections occur between the arrays, unnecessary light (stray light) enters the photodetector and causes measurement errors. As one method for avoiding this, there is a method of providing a plurality of filter members having different spectral characteristics along the arrangement direction of the light receiving elements on the front surface of the light detecting element array (see, for example, Patent Document 3 and Patent Document 4). .

However, the spectral wavelength range required by the analyzer is a very narrow band of about 10 nm. In particular, when multiple reflection occurs between the diffraction grating and the photodetector array as described above, a filter is used. It is difficult to obtain a sufficient suppression effect of stray light by the provided method. In addition, when the filter disposed on the front surface of the photodetecting element array is composed of a plurality of filter members having different spectral characteristics along the arrangement direction of the light receiving elements, reflection of light at the joining end face of each filter member, The stray light is generated by the propagation of light due to multiple reflection at the light source, causing measurement errors.
JP-A-12-180368 Japanese Patent Laid-Open No. 13-183290 Japanese Patent Publication No. 2-39726 JP-A-9-222358

An object of the present invention is to reduce the amount of a test sample or reagent used in a chemical analyzer and to improve measurement accuracy.

  In order to achieve the above object, the present invention takes the following measures.

  The viewpoint of the present invention is that light from a light source is irradiated to a reaction tube containing a mixed solution of a test sample and a reagent, the light transmitted through the reaction tube is dispersed and detected by a photodetector, and the detection result is used. A chemical analyzer for measuring a predetermined item, wherein the photodetector includes a plurality of light receiving elements arranged along a light receiving surface of the light detector and a light receiving surface of the light detector. A plurality of transmission wavelength selective filters that filter light incident on the plurality of light receiving elements, and a plurality of light shielding layers that are disposed between the adjacent transmission wavelength selective filters and have light shielding properties and antireflection properties And a chemical analyzer characterized by comprising:

  According to the present invention, it is possible to reduce the amount of the test sample and the reagent used and to improve the measurement accuracy.

  Hereinafter, a chemical analyzer according to the present invention will be described with reference to the drawings according to preferred embodiments. In the present embodiment, a slit is disposed in front of the light source, and the size of the light beam transmitted through the sample is reduced by focusing the lens between the slit and the reaction tube on the slit. Moreover, it is a plurality of filters arranged on the front surface of the light detection element array (photodiode array), and stray light is suppressed by sandwiching a layer having a light shielding property and an antireflection property between the adjacent filters. This stray light is further suppressed by disposing a mask having light shielding and antireflection properties on at least one of the front surface and the back surface of the filter.

  In addition, the light incident surface of the photodetector with respect to the optical axis of the reflecting surface of the diffraction grating is prevented so that the reflected light generated when the light beam dispersed by the diffraction grating enters the photodiode array does not return to the diffraction grating. Are arranged to be inclined (non-90 °).

  Furthermore, when there is a scatterer in the reaction solution in the color tone measurement, the measurement accuracy decreases due to detection of light with different effective optical path lengths when calculating the absorbance by multiple scattering of light. In order to suppress detection of unnecessary scattered light from the scatterer, an optical lens is arranged between the light source and the reaction tube, and the focal point of the optical lens is separated from the center of the reaction tube, that is, from the center of the reaction tube. The optical lens restricts the aperture of the incident light beam to the reaction tube and the aperture for detecting the light transmitted through the reaction tube to the desired value. To do. As a result, a small amount and improvement in measurement accuracy are achieved.

  FIG. 1 is a diagram showing a configuration of a chemical analyzer according to an embodiment of the present invention. This chemical analyzer comprises reagent containers 2 and 3 in which a reagent rack 1 containing a plurality of reagent bottles containing reagents that react with various components of a test sample can be installed, and a plurality of reaction tubes 4 on the circumference. It has the arranged reaction disk 5 and the disk sampler 6 in which the test sample container in which the test sample is stored is set. The reagent containers 2 and 3, the reaction disk 5, and the disk sampler 6 are each rotated by a driving device. Reagents necessary for the measurement are transferred from the reagent bottle 7 stored in the reagent rack 1 of the reagent storage 2 or the reagent storage 3 to the reaction tube 4 on the reaction disk 5 using the dispensing arm 8 or the dispensing arm 9 respectively. It is dispensed.

  The test sample stored in the test sample container 17 disposed on the disk sampler 6 is dispensed into the reaction tube 4 on the reaction disk 5 using the sampling arm 10. The reaction tube 4 into which the test sample and the reagent are dispensed moves to the stirring position by the rotation of the reaction disk 5, and the mixed solution of the test sample and the reagent is stirred by the stirring unit 11. Thereafter, the photometric unit 13 performs component analysis of the test sample by irradiating the reaction tube 4 moved to the photometric position with light and measuring the change in absorbance of the mixed solution. Then, the mixed liquid in the reaction tube 4 that has been analyzed is discarded, and then the reaction tube 4 is washed by the washing unit 12.

  FIG. 2 is a top view of the photometric unit 13. A pre-lamp slit 22 is disposed at a position away from the light source 21 such as a tungsten halogen lamp by a desired distance, for example, immediately before the light source 21. The hole through which the light in the lamp front slit 22 transmits is set to a desired size according to the test sample dispensed into the reaction tube 4 and the minimum amount of reagent. The hole through which the light of the slit 22 transmits is formed in a square having a side of 1 mm, for example. The light that has passed through the hole in the pre-lamp slit 22 has the heat component removed by the heat ray absorption filter 23, and the light from which the heat component has been removed by the heat ray absorption filter 23 is collected by the condenser lens 24.

  The distance between the pre-lamp slit 22 and the condensing lens 24 is set so that the optical focus of the condensing lens 24 is positioned at or near the pre-lamp slit 22. In other words, the slit 22 is disposed between the light source 21 and the condenser lens 24 and at a position away from the condenser lens 24 by its focal length. In other words, the condenser lens 24 is arranged at a position away from the slit 22 by the focal length. As a result, the light irradiated to the test sample and reagent mixture becomes a light image with less blur reflecting the size of the hole that passes through the slit 22 in front of the lamp, regardless of the size of the filament of the light source 21. . Therefore, it is possible to effectively collect the light emitted from the light source 21 and to irradiate the mixed liquid of the test sample and the reagent with a desired size.

  The light condensed by the condensing lens 24 is irradiated to the mixed solution of the test sample and the reagent in the reaction tube 4 through the light transmission window 25 disposed on the side wall portion of the reaction disk 5. At this time, the condensing lens 24 and the reaction tube are arranged such that the optical focal position of the condensing lens 24 on the reaction tube 4 side is behind the center of the reaction tube 4 by a desired distance, for example, about 5 mm to 10 mm. 4 is set to be shorter than the focal length of the condenser lens 24. In other words, the reaction tube 4 is disposed closer to the condenser lens 24 side than the focal position of the condenser lens 24.

  The light transmitted through the reaction tube 4 is collected by the condenser lens 28 through the light transmission window 26 disposed on the side wall portion of the reaction disk 5. The optical focal point of the condensing lens 28 is matched to the optical focal position of the condensing lens 24 on the reaction tube 4 side, that is, the position shifted backward by a predetermined distance from the center of the reaction tube 4 or the vicinity thereof. Thereby, the light which permeate | transmitted the reaction tube 4 can be condensed effectively, and the light absorbency of the liquid mixture of a test sample and a reagent can be measured with a sufficient precision.

  That is, the test sample dispensed into the reaction tube 4 by shifting the optical focal positions of the condenser lenses 24 and 28 arranged before and after the reaction tube 4 by a predetermined distance from the center of the reaction tube 4. Detection of light that is scattered by a scatterer contained in the mixture of the reagent and the reagent and deviates from the desired ray trajectory can be suppressed. Similarly, by adjusting the apertures (NA) of the condensing lenses 24 and 28, it is possible to suppress detection of scattered light that causes an error in absorbance measurement. The shutter 27 is opened when measuring the test sample.

  The light collected by the condensing lens 28 is narrowed down to a predetermined width by a slit 29 disposed at or near the other optical focal position of the condensing lens 28 and then irradiated to the concave diffraction grating 30.

  The concave diffraction grating 30 diffracts incident light in a desired direction for each wavelength. This diffracted light is detected for each wavelength component by the photodetector 33. The photodetector 33 includes a wavelength-selective filter array 31 with a mask and a photodiode array 32.

  FIG. 3 is a side view showing the configuration of the photometry unit 13. The concave diffraction grating 30 is arranged such that its central axis is inclined downward by θ1 with respect to the optical axis. The photodetector 33 is arranged such that the center vertical axis of the light receiving surface is inclined by θ2 with respect to the optical axis of the diffracted light. Thereby, multiple reflection between the concave diffraction grating 30 and the photodetector 33 can be prevented, and detection of stray light due to multiple reflection can be prevented.

  4A shows a sectional view of the photodetector 33, and FIG. 4B shows a top view of the photodetector 33. FIG. The photodiode array 32 includes a substrate 41 and a plurality of photodiodes (light receiving detection elements) 42 formed on the substrate 41. The plurality of photodiodes 42 are arranged in a line along the spectral direction. A filter array 31 is disposed on the front surface (light incident side) of the photodiode array 32.

  The filter array 31 includes a plurality of wavelength selective filters 43 having different wavelength selection characteristics. The plurality of filters 43 are arranged along the arrangement direction of the plurality of photodiodes 42. A light shielding layer 44 having a light shielding property and a light reflection suppressing property is disposed between adjacent filters 43. The light shielding layer 44 is formed of a material in which a black paint is mixed with an epoxy adhesive. By adopting this material, it is possible to have an adhesion function for bonding the plurality of filters 43 together.

  A mask 45 is disposed on the front surface of the filter 43. The mask 45 is a light shielding film, and a portion corresponding to the array of the photodiodes 42 is opened. Further, the mask 45 has a crosspiece portion 46 having the same light shielding property formed at a position corresponding to the light shielding layer 44.

  Detection of stray light can be suppressed by the light shielding layer 44 and the mask 45. Note that a mask having the same function and the same structure as the mask 45 may be disposed on the back surface of the filter 43 or the front surface of the photodiode 42, that is, between the filter 43 and the photodiode 42. With this mask, detection of stray light due to multiple reflection between the photodiode 42 and the filter 43 can be suppressed. Both the mask and the mask 45 may be provided, or only one of them may be provided.

  The photodiode 42 generates an electrical signal (light reception signal) corresponding to the amount of incident light. After this light reception signal is collected by the signal collection unit, it is used by the signal processing unit for calculation processing such as a change in absorbance of the test sample.

  As is clear from the above description, the automatic chemical analyzer of this embodiment reduces the amount of test sample and reagent used, and suppresses detection of stray light and scattered light, thereby reducing the desired test sample and reagent. The measurement accuracy of the change in absorbance of the mixed solution of can be improved.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention at the stage of implementation. For example, the present invention can be implemented with various modifications other than those described above, and can be applied not only to automatic chemical analyzers but also to various spectroscopic analyzers. Furthermore, the above embodiment includes various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, some constituent requirements may be deleted from all the constituent requirements shown in the embodiment.

  As described above, according to the present invention, it is possible to reduce the amount of the test sample and the reagent used and to improve the measurement accuracy.

The figure which shows the external appearance of the automatic chemical analyzer of one Embodiment of this invention. FIG. 2 is a top view showing a configuration of a photometric unit in FIG. 1. The side view which shows the structure of the photometry unit of FIG. 4A is a cross-sectional view of the photodetector of FIGS. 2 and 3, and FIG. 4B is a top view of the photodetector of FIGS.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reagent rack, 2 ... Reagent storage, 3 ... Reagent storage, 4 ... Reaction tube, 5 ... Reaction disc, 6 ... Disc sampler, 7 ... Reagent bottle, 8 ... Dispensing arm, 9 ... Dispensing arm, 10 ... Disc Sampler dispensing arm, 11 ... stirring unit, 12 ... washing unit, 13 ... photometric unit, 14 ... probe of first dispensing arm, 17 ... sample container, 21 ... light source, 22 ... slit before lamp, 23 DESCRIPTION OF SYMBOLS ... Heat ray absorption filter, 24 ... Condensing lens, 25, 26 ... Light transmission window, 27 ... Shutter, 28 ... Condensing lens, 29 ... Slit, 30 ... Concave diffraction grating, 32 ... Photodetector, 41 ... Photodiode array Substrate, 42 ... photodiode, 43 ... transmission wavelength selective filter, 44 ... light shielding layer, 45 ... mask, 46 ... mask crosspiece.

Claims (5)

The reaction tube containing the test sample and reagent mixture is irradiated with light from the light source, the light transmitted through the reaction tube is dispersed and detected by a photodetector, and measurement of a predetermined item is performed based on the detection result. A chemical analyzer to perform,
The photodetector is
A plurality of light receiving elements arranged along the light receiving surface of the photodetector;
A plurality of transmission wavelength selective filters arranged along the light receiving surface of the photodetector and filtering light incident on the plurality of light receiving elements;
A plurality of light shielding layers disposed between adjacent transmission wavelength selective filters and having light shielding properties and antireflection properties;
A chemical analysis apparatus comprising:   The chemical analyzer further comprising a mask disposed on at least one of a front surface and a back surface of the filter. An optical lens disposed between the light source and the reaction tube;
A slit disposed between the light source and the optical lens and disposed immediately before the light source;
The chemical analyzer according to claim 1 or 2, further comprising:   A diffraction grating that splits the light transmitted through the reaction tube; and a photodetector, wherein the photodetector is inclined so that a surface of the photodetector is inclined with respect to an optical axis of the diffraction grating. The chemical analysis apparatus according to claim 1, wherein the chemical analysis apparatus is disposed with respect to the first position.   5. The chemical analysis apparatus according to claim 1, wherein the reaction tube is disposed between a focal position of the optical lens opposite to the light source and the optical lens. .

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