Patent Application
20130243657
The present invention relates to an automatic analyzing apparatus which automatically analyzes a biological sample component such as blood, and in particular to a temperature adjusting mechanism of a measuring unit using an LED (Light-Emitting Diode) as a light source.
In recent years, the technological developments have increased the light intensity of LEDs (Light-Emitting Diodes) and have expanded the wavelength variations thereof. Furthermore, by making use of advantages such as high energy efficiency for light emission and small size, the range of application thereof has been expanded in various industrial fields.
Also in the field of automatic analyzing apparatus for clinical laboratory tests, demands for energy and space savings and cost reduction of the apparatus are high, and as one of the means for responding to these, the apparatus using an LED as a light source has been increasing.
When an LED is used as a light source, it is the stabilization of the light intensity that becomes a problem. It is generally known that the LED gives off heat from itself when it is energized and the light intensity and wavelength thereof are changed when temperature of a P/N junction is changed.
An automatic analyzing apparatus measures a concentration of a blood sample by irradiating a sample to be measured with light to measure a change in light intensity. Therefore, stabilization of the light intensity as a base value is essential. Also, from the demands of the market, it is desired that the start-up time of the apparatus is more reduced, and the light intensity is required to be stabilized in a shorter time.
When an LED is used as a measurement light source of an automatic analyzing apparatus, for example, Patent Document 1 suggests to perform the temperature control by mounting the LED on a member with a large heat capacity in order to obtain a stable light intensity.
Japanese Patent Application Laid-Open Publication No. 2004-101295
Incidentally, when the junction temperature of the LED increases, the light emission amount thereof tends to decrease. Since the decrease in light intensity in a measurement system using light leads to the decrease in detection sensitivity, when the LED is used as a light source of an automatic analyzing apparatus for clinical laboratory test, heat generated in the ED is required to be efficiently removed. Also, the fluctuation of the LED light intensity due to temperature change has to be prevented. Furthermore, it is also necessary to achieve a stable state at a target temperature in a shorter time.
Heat of the LED is generated at a P/N junction, and is propagated by thermal conduction to either one of two leads that is connected to a light-emission lead. Therefore, by cooling down the lead to which heat is transmitted and stabilizing its temperature, the temperature of the P/N junction is stabilized to be low, so that the decrease in the light intensity is suppressed and the stable measurement can be achieved.
However, a lead has a cross section of about 0.5 mm to 1 mm square and is extremely thin in general, and a metal member with high thermal conductivity is required to be brought into contact with the lead in order to absorb heat by thermal conduction. On the other hand, a current which makes the LED emit light flows through a lead wire, and the lead wire is required to be electrically insulated. Thus, an insulating sheet is required to be provided between the lead and the metal member. Since a material with low electric conductivity generally has a low thermal conductivity, if an insulating sheet is provided between the lead and the metal member, the heat absorption amount from the LED is significantly decreased, and as a result, the temperature cannot be sufficiently adjusted and stabilization of the light intensity of the LED cannot be expected.
An object of the present invention is to provide an automatic analyzing apparatus capable of making an adjustment to a target temperature so as to stabilize the light intensity of an LED and also capable of making the adjustment to that temperature in a short time.
The above and other objects and novel characteristics of the present invention will be apparent from the description of the present specification and the accompanying drawings.
The following is a brief description of an outline of the typical invention disclosed in the present application.
More specifically, an automatic analyzing apparatus according to the present invention is an automatic analyzing apparatus including: a light-emitting diode light source; and a temperature adjusting mechanism for the light-emitting diode light source, and the temperature adjusting mechanism is made up of a metal member provided with the light-emitting diode light source; a water-flowing pipe buried in the metal member and allowing constant-temperature bath water to flow therein; and a small metal piece member bringing only a heat-generating lead of the light-emitting diode light source into direct contact with the metal member.
The effects obtained by typical embodiments of the invention disclosed in the present application will be briefly described below.
According to the present invention, in the automatic analyzing apparatus, since only the lead of the LED from which heat is generated is brought into direct contact with the metal member of the temperature adjusting mechanism, cooling is carried out by transmitting heat of the constant-temperature bath water only to the lead, which is a part required for temperature adjustment of the LED, from the metal member in a short time. In other words, the temperature adjusting mechanism can make an adjustment to a target temperature so as to stabilize the light intensity of the LED, and the adjustment to that temperature can be made in a short time.
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted as much as possible.
In the configuration of an automatic analyzing apparatus 1, while moving vertically and rotating, a sampling arm 20 of a sampling mechanism 10 sucks a test sample in a sample container 101 placed on a sample disk 102 rotating laterally by using a sample dispensing probe 105 attached to the sampling arm 20, and discharges the test sample to a reaction container 106. As can be seen from
The configuration of the automatic analyzing apparatus 1 in
An analytical item to be analyzed for each sample is inputted from an input device such as a keyboard 121 or a screen of a CRT 118. The operation of each unit in the automatic analyzing apparatus 1 is controlled by the computer 103.
Along with the intermittent rotation of the sample disk 102, the sample container 101 is transferred to a sample suction position, and the sample dispensing probe 105 descends into the sample container 101 at a stop. When the tip of the sample dispensing probe 105 is brought into contact with the liquid level of the sample as a result of the descending operation, a detection signal is outputted from a liquid level detection circuit 151, and the computer 103 controls to stop the descending operation of a driving unit of the sampling arm 20 based on the signal,
Next, after a predetermined amount of the sample is sucked into the sample dispensing probe 105, the sample dispensing probe 105 ascends to a top dead center. While the sample dispensing probe 105 is sucking a predetermined amount of the sample, the fluctuation in pressure in a flow path between the sample dispensing probe 105 and the sample syringe pump 107 during the sucking operation is monitored by a pressure detection circuit 153 by using a signal from a pressure sensor 152, if an anomaly is detected in the pressure fluctuation during the suction, there is a high possibility that a predetermined amount has not been sucked, and therefore an alarm is provided to analytical data in that case.
Next, the sampling arm 20 turns around in a horizontal direction, causes the sample dispensing probe 105 to descend at the position of the reaction container 106 on a reaction disk 109, and then discharges the retained sample into the reaction container 106. Next, the reaction container 106 containing the sample is moved to a reagent addition position. On a rotatable reagent disk 125, reagent bottles 112 corresponding to a plurality of analytic items to be analyzed are disposed. The reagent dispensing probe 110 attached to the sampling arm 20 dispenses a predetermined amount of the reagent from the reagent bottle 112 to the reaction container 106 A mixture in the reaction container 106 having the sample and the reagent added thereto is agitated by an agitator 113.
The reaction container 106 having the mixture accommodated therein is transferred to a position between a light source 114 and a photometer 115 serving as measuring means, and the light intensity is measured by the photometer 115 based on irradiated light from the light source 114 to the reaction container 106, A light measurement signal is outputted for print through an A/D converter 116 and via an interface 104 to a printer 117, or is outputted onto the screen of the CRT 118 and stored in a hard disk 122 serving as a memory. The reaction container 106 for which light measurement has been completed is cleaned at the position of a cleaning mechanism 119. A cleaning pump 120 supplies washing water to the reaction container 106 and discharges waste liquid from the reaction container 106. In the example of
As the light source 114, an LED (Light-Emitting Diode) light source is used. Also, in order to stabilize the changes in the light intensity of the LED due to the temperature and enable the measurement with high reproducibility, a temperature adjusting mechanism for the LED is provided.
As shown in
The entire metal member 202 is covered with a heat insulator 205. In the metal member 202, a portion of the metal pipe 203 bent in a U shape is buried, and water from a constant-temperature bath 206 (constant-temperature bath water) flows into this metal pipe 203 to adjust the metal member 202 to a target temperature, As a material of the metal member 202, for example, copper, iron, or the like is preferable because of high thermal conductivity.
The light source 114 is made up of a light-emitting unit 251 and leads 252 and 253 extending from the light-emitting unit 251, In the example of
More specifically, as particularly shown in
On the other hand, the non-heat-generating lead 253 is covered with a heat insulator (insulating member) 254 with insulating properties so as not to be influenced by the temperature change of the metal member 202, Note that preferable materials of the pins 204 are similar to those of the metal member 202.
With the structure described above, thermal resistance between the metal member 202 and the lead 252 is nearly eliminated, and therefore heat is transferred to the lead 252 in approximately the same time as the time in which heat of constant-temperature water is transferred to the metal member 202. A contact surface between the metal member 202 and the metal pipes 203 is taken as widely as possible, whereby heat transfer efficiency is further improved, and as a result, the temperature can be adjusted to the target temperature in a short time.
In this case, heat of constant-temperature water is transmitted to the metal member 202 in a short time, but a thermal conductivity of the thermally conductive sheet 260 described above is about 1/4000 to 1/6000 compared with that of a metal, and therefore thermal resistance is high after all. Moreover, since lead dimensions of a general LED are such that the cross-sectional area is about 0.5 mm and the length is about 20 mm, the heat transfer area is extremely small, and thermal conduction efficiency is low.
In other words, in the present invention, since the pins 204 that bring only the heat-generating lead 252 into direct contact with the metal member 202 are provided in the temperature adjusting mechanism of the LED, heat of the metal member 202 can be transmitted only to the lead 252 in a short time, and temperature adjustment for cooling to the target temperature can be made in a short time. This is particularly advantageous in the measurement of scattered light, in which values tend to vary due to that the measurement is carried out only with absolute values, because it is possible to promptly achieve the state in which desired reproducibility is obtained. Also, since influences due to temperature change of the light source 114 can be further decreased by covering the non-heat-generating lead 253 with the heat insulator 254, the light intensity of the LED can be further stabilized, and measurement with higher reproducibility can be made.
In the temperature adjusting mechanism 401, a portion of each metal pipe 203 buried in the metal member 202 is covered with an insulating member 402 in order to electrically insulate the metal pipes 203 and the metal member 202. As the insulating member 402, for example, a material similar to that of the thermally conductive sheet 260 can be suitably used. Note that the configuration other than that is similar to that of the temperature adjusting mechanism 201,
In this case, the insulating member 402 covering the metal pipes 203 serves as a heat resistance, but since a significantly wider heat transfer area can be taken compared with the case in which the thermally conductive sheet 260 is present between the leads 252 and 253 and the metal member 202 like in the temperature adjusting mechanism 301, thermal conduction efficiency is extremely high.
Thus, also when an element like this is used, temperature adjustment can be efficiently made in a short time compared with the case in which temperature adjustment is made in the state where the leads 252 and 253 are covered with the thermally conductive sheet 260.
In the foregoing, the invention made by the inventors of the present invention has been concretely described based on the embodiments, However, it is needless to say that the present invention is not limited to the foregoing embodiments and various modifications and alterations can be made within the scope of the present invention.
Thermal conduction efficiency of the temperature adjusting mechanism is modeled and verified.
(Verification 1)
In the configuration of a temperature adjusting mechanism 501 of this verification model, in order to make conditions uniform with those of verification of the temperature adjusting mechanism 401 shown in
The insulting member 402 is a thermally conductive sheet with a thermal conductivity of 0.8 W/m·K, and a thickness a thereof is 1 mm. The metal pipe 203 has a width b of 40 mm, a pipe diameter c of 4 mm, and a buried depth d into the metal member 202 of 20 mm. The thermally conductive sheet 260 is made of a material similar to that of the insulating member 402 and has a length e of 10 mm and a thickness f of 1 mm. Also, the leads 252 and 253 are formed to have a side g of 0.5 mm. As a temperature condition, the heat-generating lead 252 at 47° C. is assumed to be cooled down to 37° C.
The amount of thermal conduction per unit time (second) under the conditions described above is calculated by applying to the following equations.
Q (heat quantity)=λ(thermal conductivity)×S (thermally conductive area)×(T1×T2 (temperature change))/h (thickness)
λ (thermal conductivity)=thermally conductive sheet 260=0.8 W/m·K
S (thermally conductive area)=area in which the heat-generating lead 252 and the thermally conductive sheet 260 are in contact with each other=0.5 mm×10 mm×2 (because upper and lower parts of the lead 252 are in contact with the thermally conductive sheet 260)=10 mm2=10×10−6 m2
T
1
−T
2 (temperature change)=47−37=10 K
h (thickness)=thickness f of thermally conductive sheet 260 =1 mm=1×10−3 m
Accordingly, the thermal conduction efficiency in the configuration of
Q=0.8 W/m·K×10×10−6m2×10 K/1×10−3 m=8×10−2 W/S =0.08 J
(Verification 2)
Next, the temperature adjusting mechanism 401 of the present invention shown in
In the verification of this temperature adjusting mechanism 401, since the lead 252 and the metal member 202 are both made of metal, it is assumed that no thermal resistance is present and heat exchange occurs between the metal pipe 203 and the metal member 202.
λ (thermal conductivity)=thermally conductive sheet (insulating member) 402=0.8 W/m·K
S (thermally conductive area)=4 (pipe diameter)×π×½ (½ of a pipe circumference)×36×π×½+2+2 (length of pipe center part is used for simplification)×2 (because upper and lower parts of the metal pipe 203 are in contact with the thermally conductive sheet 402)=760.13 mm2=760×10−6 m2
T
1
−T
2 (temperature change)−47 37=10 K
h (thickness)=thickness f of the thermally conductive sheet 260=1 mm =1×10−3 m
Accordingly, thermal conduction efficiency in the configuration of
Q=0.8 W/m·K×760×10−6 m2 ×10 K/1×10−3 m=6.08 W/S=6.08 J
Although the verification described above is merely an example, while a thermal conductivity per second of the temperature adjusting mechanism 501 of
The present invention relates to an automatic analyzing apparatus which automatically analyzes a biological sample component such as blood, and can be widely applied to an apparatus or system having a temperature adjusting mechanism of a measuring unit using an LED (light-emitting diode) as a light source,
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-257446 | Nov 2010 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2011/073940 | 10/19/2011 | WO | 00 | 5/17/2013 |
