The present invention relates to a reaction cell for use in an automatic biochemical analyzer and an automatic biochemical analyzer using the same.
An automatic biochemical analyzer is an apparatus for automatically performing absorption spectroscopy of blood serum components. The absorption spectroscopy of blood serum components is a technique for estimating contents of components such as carbohydrates, proteins, and minerals present in a serum, by mixing and reacting a reagent with the serum, allowing various wavelengths of light to penetrate the obtained mixture, and measuring absorbance at the wavelengths, and used in health checkup and other examinations.
A container in which the serum and the reagent are mixed is called a reaction cell 904. For transmitting a light beam, the reaction cell 904 desirably has high transmittances in a band of from 100 nm to 1000 nm including visual light. As such, an optical material is used as a material for a reaction cell. In addition, from the viewpoint of the analytical efficiency, parallel rays are used as a transmitted beam for the purpose of collecting the transmitted beam on one position without dispersion to perform the analysis, and the reaction cell is generally in a box shape in which flat plates are assembled. Amounts of the serum and reagent required for achieving highly reliable analysis are several microliters to several tens of microliters, and a typical size of a reaction cell is several tens of square millimeters in cross section and several tens of millimeters in height. A region used for the photometry in the analysis is restricted at a height several millimeters from the cell bottom.
Automatic biochemical analyzers are sometimes designed in the following manner from the viewpoint of automatically analyzing a large number of serums at high speed. Reaction cells are arranged on the periphery of a disk or the like, a light source is placed on the center of the circle and a diffraction grating is placed in a direction of a radius vector, and the disk is rotated to perform photometry of the reaction cells one by one.
Here, reaction cells are basically consumable, and thus high productivity is required to response daily huge number of biochemical examinations. For this reason, a reaction cell is molded and fabricated into a box by injection molding from an optical resin or an optical glass. In addition, from the viewpoint of enhancing productivity and reducing cost, a reaction cell in which several to several tens of cells are integrally molded (hereinafter referred to as a serial cell) may be used in some cases. Molding of such a serial cell is disclosed in PTL 1.
PTL 1: JP-A-2005-283539
In molding and manufacturing reaction cells, molding failure is often a problem. Molding failure includes weld and foreign matter. Weld among them is an uncharged portion solidified and forms a micro notch shape. When weld is present in a beam transmission part, light scattering occurs in the photometry to decrease the analytical efficiency, sometimes resulting in a measurement error. For this reason, when weld is recognized in a beam transmission part in inspection after molding, such a product is eliminated from the products to be shipped as a defective. In particular, as for the serial cell mentioned above, even when only one cell among the plural cells is failed in molding, the entire serial cell including the other cells integrated therewith becomes a defective product. Accordingly, in such a serial cell, the effect of weld generation in a beam transmission part on the yield is larger than that in single cell molding, and weld becomes a more serious problem.
If weld is present, furthermore, when the cell receives an impact, for example, upon careless falling in conveyance or upon contact with a nozzle in dispensing a specimen (serum), a stress concentration on a notch tip of the weld possibly triggers cell fracture. It is therefore desirable that no weld is present over the entire cell. It is desirable that no weld is present at least in the beam transmission part.
Thus, an object of the present invention is to provide a reaction cell for automatic biochemical analyzer in which weld generation in beam transmission parts is prevented to reduce scattering of transmitted beam, thereby having a stable transmissivity to achieve high analytical efficiency.
It has been found that, in the weld generation, a position and a merging angle of a merging section of a resin in molding depend on the resin charging pattern, and that the resin charging pattern substantially depends on the size and shape of a cavity. Accordingly, it can be said that it is important to design the size and shape of a cavity so that no resin merging is produced on charging.
However, it is actually difficult to avoid resin merging in many cases. As a countermeasure, devises are conceivable such as providing a vent (exhaust opening of a mold cavity) in the vicinity of the resin merging position and forcing to produce weld in a position that does not impair performance of the product. In the case of a serial cell, however, since intervals between cells are as small as several millimeters, it is difficult to provide a vent for each cell.
For solving the above problem, the reaction cell of the present invention has the following characteristics.
The reaction cell of the invention is a bottomed reaction cell having an opening formed at one end. The reaction cell comprises a tube wall including a pair of walls facing to each other and two side walls each connected to each of the pair of walls via a corner portion. The pair of walls each have a thickness larger than thicknesses of the corner portions that are connected to the wall, and have a uniform thickness over the entire wall. Alternatively, when each wall has a maximum value in thickness in a part of the wall, the wall thickness monotonically decreases from the part having the maximum value to the corner portion.
According to the present invention, it is possible to provide a reaction cell for automatic biochemical analyzer in which weld generation in a beam transmission part is prevented, whereby stable transmissivity can be achieved.
The present invention will be described in detail herein below with reference to examples.
a1>b1, a1>b2, a2>b3, and a2>b4
From the top opening of the reaction cell 100 shown in the bird's-eye view
The reaction cell 100 filled with the specimen is irradiated with light beam, and the beam is transmitted. from the flat plate 120 to the flat plate 110, or from 110 to 120 shown in
Thus, the aforementioned shape according to the present invention is adopted, whereby weld generation in a beam transmission part can be prevented to achieve stable transmissivity. The reason is described below in comparison with a conventional shape.
Schematic diagrams of explaining the mechanism of weld generation are shown in
As shown in
As a result, in resin charging in molding, the corner portions are charged earlier than the beam transmission parts. The reason is that resin flows preferentially into a part having a smaller flow resistance. Flow resistance is directly proportional to the cube of the thickness, and the smaller the thickness, the larger the flow resistance. For this reason, the charging rate in the beam transmission part having a smaller thickness is lower than that in the corner portions, and resin merging occurs in the beam transmission part.
For verifying this phenomenon, a resin charging process was computed using a molding simulation software. The results are shown in
On contrary, in the cell shape of the present invention shown in
The flow rate in the short side flat plate portions which are beam transmission parts are increased relative to the corner portions, and as a result, resin merging is not recognized in the short side flat plate portions, and weld generation can be prevented. Incidentally, the thicknesses of the short side corner portions are not required to be the same. The reason is described with reference to
Generally in a reaction cell, in view of the parallel property of the transmitted beam, flat plates each having a constant thickness are used for the short side walls. However, it is difficult to make a flat plate having a strictly constant thickness for the precision limit of the molding processing or other reasons. Nevertheless, when the variation of the thickness by position in a beam transmission part is within 10 μm and the thicknesses of the corner portions are smaller than the thickness of the beam transmission part including the variation, the present invention is advantageous.
If the parallel property of the transmitted beam is sacrificed to some extent, the thickness is not necessarily required to be constant. In this case, for the reason mentioned above, when a shape is adopted in which the tube wall thickness of the reaction cell has a maximum value in a part and the thickness monotonically decreases from the part having the maximum value to a short side corner portion, merging does not occur when a resin flows into the mold, and no weld is generated.
In the case of
The case of
In the case of
In
From
According to this embodiment, therefore, it is possible to prevent weld generation in the beam transmission parts to thereby provide a reaction cell for automatic biochemical analyzer having high analytical efficiency in which scattering of a transmitted beam is reduced to achieve a stable transmissivity.
In the reaction cell shown in
In this embodiment, by adopting a shape in which the cell thickness gradually varies as shown in
During the analysis, the cell is immersed in a liquid with a controlled temperature for the purpose of controlling the serum temperature, but air bubbles, if deposited on the surface for the photometry, may induce a measurement error. However, by adopting the shape shown in this embodiment, deposition and remaining of air bubbles can be reduced, and therefore inducement of a measurement error can be advantageously prevented.
The reaction cell 700 comprises two pairs of flat plates 710 and 720, and 730 and 740, each pair facing to each other, a corner portion 750 connecting the flat plates 710 and 730, a corner portion 760 connecting the flat plates 710 and 740, a corner portion 770 connecting the flat plates 720 and 730, a corner portion 780 connecting the flat plates 720 and 740, and a bottom 790, and has a gate 791 in the center of the rear surface of the bottom 790.
This cell satisfies the following relationships between the thicknesses d1 and d2 of the short sides at a height from the cell bottom and the thicknesses e1 and e2 of the long sides at the same height h:
d1>e1, d1>e2, d2>e1, and d2>e2
Accordingly, also in the shape shown in this example, no resin merging is recognized in the short side flat plate portions which are beam transmission parts, and weld generation can be prevented. Unlike in Example 1, the effect of avoiding resin merging in the beam transmission parts is limited to a certain height from the cell bottom having the gate in this example. However, since the range used for photometry during the analysis can be made within the range where the effect is given, there is no problem in practice.
This embodiment relates to an automatic biochemical analyzer which automatically performs absorption spectroscopy using a reaction cell according to any one of Embodiments 1 to 3.
As shown in
The reaction cell is filled with a test liquid in which a serum is mixed and reacted with a reagent. The reaction cell is then irradiated with a light beam having wavelengths in a band of from 100 nm to 1000 nm including visual light to allow the light beam to transmit through the test liquid. The absorbance at the wavelengths of the transmitted beam are measured to estimate contents of components, such as carbohydrates, proteins, and minerals, present in the serum.
In the reaction cells according to the Embodiments described above, no weld is generated at least in the beam transmission parts.
Since the decrease of analytical efficiency due to light scattering in the photometry therefore does not occur and no measurement error occurs, it is possible to provide an automatic biochemical analyzer having high analytical precision which is equipped with reaction cells having stable transmissivity.
In addition, the configuration of the present invention is realized not only in the beam transmission parts but also over a wide range of the beam transmission surface, and still over the entire beam transmission surface. This is obviously preferable.
Number | Date | Country | Kind |
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2014-031886 | Feb 2014 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2015/053608 | 2/10/2015 | WO | 00 |