JPH01229940A - Cuvet for optical analysis - Google Patents

Abstract

PURPOSE:To obtain a stable measured value even when a light transmitting part is moved, by keeping the distance between the light source part of the probe mounted to a cuvet and a light detection part constant. CONSTITUTION:Pipes 24, 25 are mounted to pipes 10, 11 through opening and closing cocks 22, 23 and a cuvet 30 is fixed in a vertically erected state. The probe of an analyzer is engaged with a notch part 21 to mount the light emitting part 31 of the probe to the light transmitting part 16 of the central part of a rigid plate 1 and a light detection part 32 is mounted to the central part of a rigid plate 7. Herein, opening and closing cocks 22, 23, 26 are fully opened to inject a specimen in the cuvet 30 and, when a specimen tank 15 is filled with a specimen, the cocks 22, 26 are closed while the cock 23 is opened and, when the pipe having elasticity is picked by fingertips to be pressed, an elastic plate 4 is bent by the pressure of the specimen and returned to the original state when pressure is released. When this operation is repeatedly performed, the thickness of the specimen tank 15 varies as if by pulsating arterial blood and the light emitted from the light emitting part 31 to reach the light detection part during this variation is photoelectrically converted and the analytical result of the specimen can be displayed on the analyzer.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is directed to receiving light emitted from a light source section through a sample to a light receiving section, and detecting the above-mentioned light according to the intensity of the transmitted light. The present invention relates to a cuvette for optical analysis used in an analyzer that performs optical analysis of the sample based on the output of a light receiving section. Specifically, the above-mentioned analyzer is a device such as a pulse oximeter that uses pulsations in the internal pressure of the sample and performs optical analysis based on changes in the amount of transmitted light according to changes in the thickness of the sample layer, or This is an apparatus that changes the amount of transmitted light by changing the thickness of the sample N tank for a sample whose internal pressure does not pulsate, and performs optical analysis based on the change in the amount of transmitted light of the sample.

(Prior art) A pulse oximeter irradiates living tissue with light of multiple different wavelengths and detects the arc of transmitted light of each wavelength that changes as the thickness of the blood layer of arterial blood changes due to pulsation. The oxygen saturation level of arterial blood is determined from these measurements.Calibration of such a pulse oximeter is absolutely necessary for actual use.The calibration is performed by the manufacturer, for example, on the pulse oximeter produced by the pulse oximeter. It is necessary to evaluate the performance of the oximeter, it is necessary for the user to check the accuracy before use, and it is necessary in the event of failure or repair. This can be done by comparing the measured values obtained by applying an oximeter to a living body and the values obtained by collecting arterial blood from that living body.However, as mentioned above, calibration may be required. This type of calibration method is inconvenient because it requires a large number of tests, and it must be performed at any location and time any number of times, and over a sufficiently wide range of oxygen saturation values.Alternatively, Blood is placed in a sample tank whose walls are made up of two parallel, light-transmitting plates, and a cuvette is constructed in which the distance between the two plates is changed by the pulsation of the blood internal pressure using an elastic tube. Can be used.

However, if the probe of the device to be calibrated is directly attached to such a cuvette, the positional relationship between the light emitting part and the light receiving part changes when the sample layer is pulsated, resulting in measurement errors. For example, periodic deviations in the optical axes between the light emitting part and the light receiving part, as well as periodic deviations in the mounting positions of the light emitting part and the light receiving part installed on each flat plate, occur, resulting in various errors. come.

On the other hand, in general, optical analysis of the components of a sample involves placing the sample in a sample tank with two transparent flat plates, transmitting light through these transparent plates and the sample interposed between them, and measuring the degree of light attenuation. Analyzing samples. In this type of conventional general method, it is necessary that the distance between the two plates be accurately measured in advance, and if there is light absorption in the two plates, it is necessary to correct it. However, if a sample is analyzed using the principle of a pulse oximeter, the distance between the two plates does not necessarily need to be measured correctly, and the two plates themselves may have light attenuation characteristics. However, when conducting analysis using this method, there were no suitable cuvettes to be used.

(Problems to be Solved by the Invention) In optical analysis using a conventional cuvette, when the probe of an analyzer is attached to the cuvette, the distance between the light source section and the light receiving section and the mutual positional relationship are Because of this change, the output of the light receiving section was not a correct measurement value, causing a large error in the analysis results. The present invention was made in view of these problems, and it is an object of the present invention to provide a cuvette for optical analysis that allows accurate optical analysis.

[Structure of the Invention] (Means for Solving the Problems) Therefore, in the first invention of the present application, the wall portions at two predetermined locations that accommodate the sample and face each other are light transmitting portions having light transmitting properties. and a sample tank provided with an opening that serves as an entrance and exit for the sample, and a sample tank that supports the light source section and the light receiving section while maintaining a predetermined distance between them, and the light source section and the light receiving section. A support means is provided between them and the sample tank in a state where the two light transmitting parts face each other, and when the sample tank is applied with a predetermined force, at least one of the two light transmitting parts It is configured to move in a direction toward or away from the adjacent light source section or light receiving section.

Furthermore, in a second aspect of the present application, a collimator is added to the configuration of the first aspect described above, which is disposed between the light source section or the light receiving section and the moving light transmitting section.

Here, a collimator is a light guide path that allows only parallel light to pass through and blocks other light, and specifically,
It consists of a long and thin conduit made of light-absorbing material or an optical fiber.

Furthermore, in a third invention of the present application, a mask provided between the light source section and the sample tank or between the light receiving section and the sample tank is added to the configuration of the first invention. The structure is as follows.

Furthermore, in a fourth invention of the present application, a sample temperature holding means for keeping the sample at a predetermined temperature is added to the structure of the first invention.

Furthermore, in a fifth invention of the present application, in the first invention, the light transmitting portion on the non-moving side is made light scattering.

(Function) In the first invention, the light source section and the light receiving section of the probe mounted on the present cuvette are supported by the supporting means so that the distance between them is maintained constant.

Therefore, even if the light transmitting section moves due to a predetermined force applied from the outside, the distance between the light source section and the light receiving section remains constant, and the mounting positions thereof will not shift.

In the second invention, the following effects can be obtained in addition to the effects of the first invention. When the light is scattering, when the light transmitting part moves relative to the light source part in contact with the collimator, the intensity of the light per unit area that hits the light transmitting part changes if there is no collimator during this period.

However, in the present invention, since the collimator is provided between the light source section and the light transmitting section, the intensity of light per unit area is not affected by the movement of the collimator. Similarly, even if the light transmitting part moves relative to the light receiving part in contact with the collimator, the intensity of light per unit area received by the light receiving part is not affected by the movement because the collimator is provided between them.

In the third invention, in addition to the effect of the first invention, there is an effect of selecting only light convenient for measurement from among the light immediately after the mask is irradiated from the light source section or the light immediately before the light receiving section receives it. is obtained.

In the fourth invention, the sample inside the cubera 1 is maintained at a predetermined temperature. Therefore, the optical analysis device can be calibrated accurately.

In the fifth invention, the light transmitted through the light transmitting portion on the non-moving side becomes scattered light.

(Example) Fig. 2 is a perspective view showing the concept of the cuvette of the present invention, Fig. 1 is a sectional view taken along the line A-A shown in Fig. 2, and Fig. 3 is an exploded perspective view of the cuvette of the present invention. Illustrated.

As shown in these figures, this cuvette is made up of a plurality of plate-like parts fixed together with screws. 1 in the diagram is 1111
2 is a mask, 3 is a spacer, 4 is an elastic plate, 5 is a spacer, 6 is a collimator, and 7 is a rigid plate. These are arranged in the above order and secured by screws 8 and nuts 9 in a closely overlapping state.

The rigid plate 1 is provided with two holes, into which tubes 10.11 are fitted and implanted, respectively. The rigid plate 1 is light-transmissive and light-scattering, and is made of acrylic resin. The tubes 10 and 11 are also made of acrylic resin.

The mask 2 is provided with holes 2a and 2b at its center and at positions corresponding to the two holes in the rigid plate 1, respectively. The mask 2 may be one in which a light-blocking paint is applied to the back side of the rigid plate 1.

The spacer 3 is to serve as a sample tank, and has a hole 3a extending from the center in the longitudinal direction.

The material is synthetic rubber.

The elastic plate 4 is a film-like member having elasticity, and is made of plastic.

The spacer 5 is for securing the space necessary for the bending of the elastic plate 4, and is provided with a hole 5a for this purpose.

The collimator 6 is a light-absorbing plate-like member provided with a hole 6a. The material is acrylic resin.

Like the rigid plate 1, the rigid plate 7 is light-transmissive and light-scattering. The material is acrylic resin.

In the Htl configured in this way, the rigid plate 1, the mask 2, the spacer 3, and the elastic plate 4 form a sample tank 15, and the central part of the rigid plate 1 and the elastic plate 4 opposite to this central part form a sample tank 15.
The portions become the light transmitting parts 16 and 17 of the sample tank 15, respectively.

Moreover, the passages of the tubes 10.11 are openings 18.19 that serve as inlets and outlets for the sample, respectively. Incidentally, since the supporting means consists of the rigid plate 1 and the rigid plate 7, means for keeping the distance between them constant, and means for supporting the sample tank 15, among the members used here, the tube 10. It is composed of all except 11.

Furthermore, the structure with the notch 21 as shown in FIG. 2 is such that when a probe is attached to this cuvette,
This is to make it easier to position the light emitting part and the light receiving part in the center of the rigid plate 1.7, and to ensure that the contact area of each plate member is large so that the sample does not leak from the cuvette. It's for a reason.

Next, the function of the cuvette thus constructed will be explained along with how to use it. When using this cuvette,
The operator first attaches the tubes 24 and 25 to the tubes io and 1i via the open/close cocks 22 and 23 as shown in FIG. 4, and then attaches the tube 27 to the tube 25 via the open/close cock 26. Then, the cuvette 30 is fixed vertically. The reason why the cuvette 30 is set vertically in this way is that the air inside the sample tank 15 can be easily removed. Next, the operator fits the probe of the analyzer into the notch 21 shown in FIG. The light receiving section 32 is attached to the center of the rigid plate 7 facing the light transmitting section 16 . When the probe is attached to the cuvette 30 in this way, the light emitted from the light emitting section 31 is directed to the rigid plate 1 and the mask 2, as shown by the arrow X in FIG.
hole 2a of spacer 3, elastic plate 4, hole 5a of spacer 5, hole 6a of collimator 6, and rigid plate 7.
The light reaches the light receiving section 32 through the.

The operator operates the opening/closing cock 22.23°26 shown in Fig. 4.
The sample is injected into the cuvette 30 with all doors open.

When the sample tank 15 shown in FIG. 1 is filled with a sample, the open/close cock 22 and the open/close cock 26 are closed. The opening/closing cock 23 is open. The tube 25 is made of an elastic material, and the operator pinches and compresses the tube 25 with his fingertips. At this time, the sample tank 15 is sealed and the sample is pressed against it, so that the elastic plate 4 is bent toward the hole 5a of the spacer 5 due to the pressure of the sample. When the operator releases this pressure, the elastic plate 4 returns to its original state due to its elasticity.

If such an operation is repeated, the elastic plate 4 will change, and the thickness of the sample tank 15 will change as if it were caused by pulsating arterial blood. The light that reaches the light receiving section 32 during this fluctuation is photoelectrically converted into an electrical signal, and the signal is sent to the analyzer. The analyzer then displays the analysis results of the sample.

Here, if we talk about the case where a cuvette is used to calibrate a pulse oximeter, the oxygen saturation level of the blood in the cuvette 30 can be accurately measured using, for example, a CO oximeter. By determining the relationship between the value displayed by the meter and the oxygen saturation of the blood in the cuvette 30, the calibration can be performed.

According to this embodiment, since light-scattering materials are used for both the rigid plates 1 and 7, the light-emitting parts 31 attached to each
Even if the position of the light receiving section 32 shifts somewhat during measurement, the influence of the shift can be reduced.

Further, according to this embodiment, the collimator 6 is arranged between the elastic plate 4 and the rigid plate 7. In this embodiment, the light emitting section 31
Since the rigid plate 1 to which the sample tank 1 is attached is light-scattering,
The incident light of 5 is scattered light, and the transmitted light of sample tank 15 is also scattered light. The light transmitted through the elastic plate 4 is sent to a collimator 6,
The light reaches the light-receiving surface of the light-receiving section 32 via the rigid plate 7, but if there is no collimator 6, the amount of light that enters the light-receiving surface will not accurately change depending on the thickness of the sample tank 15. This is because the scattered light attenuates with distance, which causes errors in the amount of scattered light received due to variations in the distance between the source of the scattered light, that is, the elastic plate 4, and the light receiving surface. The collimator 6 is provided to correct this error. That is, from the light transmitted through the elastic plate 4, only parallel light is extracted by the collimator 6 and reaches the light receiving section 32 via the rigid plate 7. In this way, even if the light transmitted through the elastic plate 4 is scattered light, the light receiving section 32 can accurately receive the amount of light according to the thickness of the sample in the sample tank 15.

Further, in this embodiment, a mask 2 is provided between the rigid plate 1 and the spacer 3. This mask 2 is provided so that the incident light passes through the center of the cuvette, and with this mask 2, the deflection of the elastic plate 4 is large at the center, and the influence of such non-uniformity is reduced at the periphery. This makes it possible to measure only the central part.

FIG. 5 is an exploded view of another embodiment of the invention.

As shown in this figure, the structure of this cuvette is similar to the first one above.
It is the same as the embodiment. However, in this cuvette, a light emitting section is attached to the rigid plate 7 side, and a light receiving section is attached to the rigid plate 1 side. Therefore, the light emitted from the light emitting section passes through the rigid plate 7, collimator 6, spacer 5, elastic plate 4, spacer 3, mask 2, and rigid plate 1, and reaches the light receiving section, as shown by arrow Y in FIG. . In the case of this embodiment, the light before entering the elastic plate 4 is converted into only parallel light by the collimator 6. In this way, even if the elastic plate 4 changes, the amount of light hitting the elastic plate 4 will remain constant. In this embodiment, the mask 2 allows only the light passing through the center of the rigid plate 1 to reach the light receiving section.

In this cuvette as well, a sample is filled in a sample tank, and the internal pressure of the sample is changed to cause the elastic plate 4 to vary, thereby changing the thickness of the sample tank.

In the embodiment shown in FIG. 6, the elastic plate 4 is displaced by a handle 40 attached to the elastic plate 4. In this embodiment, the same components as shown in FIG. 1 are given the same numbers and their explanations will be omitted. This handle 40 is made of a rod-like member formed in a U-shape, and both ends thereof are fixed to the elastic plate 4. The portion perpendicular to the elastic plate 4 is inserted through two holes bored in the collimator 6 and the rigid plate 7. A knob 42 is provided in a portion of the handle 40 that is parallel to the elastic plate 4.

To use this embodiment, first the sample tank 15 is filled with a sample. In this case as well, as shown in Figure 4, if the cock and sedge hat are connected to the tubes 10 and 11 and used vertically, the sample tank 15
You can completely expel the air inside. However, in this case, sample tank 1
5 is used in a state where it is opened to the outside via a pipe 10 or a pipe 11. The operator then turns the knob 42 on the handle 40.
When the handle 40 is moved in a direction perpendicular to the elastic plate 4 while holding the elastic plate 4, the elastic plate 4 is also moved accordingly. At this time, the thickness of the sample tank 15 changes in the same manner as the change due to the internal pressure of the sample.

In the embodiment shown in FIG. 7, a piston 50 is provided in place of the elastic plate 4 in the embodiment shown in FIG. This piston 50 is light-transmissive and light-scattering. In this embodiment, the same components as shown in FIG. 1 are given the same numbers and their explanations will be omitted. and the first
The hole 5a of the spacer 5 in the illustrated embodiment is a cylinder 51. The piston 50 is configured to move within this cylinder 51. The piston 50 is mounted with a handle 40 similar to that shown in FIG. 6 inserted through two holes 41 formed in the collimator 6 and the rigid body 7. Even with such a structure, the same operation and effect as the embodiment shown in FIG. 6 can be obtained.

In addition, in order to calibrate devices such as pulse oximeters that measure light-absorbing substances in blood using the pulsations of transmitted light based on the arterial blood of a living body, the blood in the sample tank must have a high S degree. Add albumin solution. This is due to the following reason. Compared to the light scattering of red blood cells in a cuvette, the light scattering of red blood cells in living tissue is weaker. The reason for this is probably that red blood cells in biological tissues are extremely thinly distributed within the tissue, and many of the red blood cells are in direct contact with the tissue, causing little reflection and refraction of light at the interface. In order to simulate this condition in a cuvette, a fluid with a high refractive index is introduced into the blood. Albumin liquid is one example of such a fluid.

Also, light-absorbing substances in the blood, such as hemog. Since a bottle has different light absorption characteristics depending on its temperature, in each example, if the temperature is set to 37°C, which is equal to body temperature, it is possible to accurately calibrate a device that performs optical analysis of blood, such as a pulse oximeter. Can be done.

The embodiment shown in FIG. 8 is a diagram showing a cuvette provided with sample temperature holding means for maintaining the temperature of the sample. Since the cuvette main body in this embodiment is similar to that shown in FIG. 5, each part is given the same number and a description thereof will be omitted. The sample temperature maintaining means in this embodiment is tube 10.1.
a heat exchanger 61 provided so as to cover the surface of the cuvette body except for 1 and the space necessary for mounting the probe;
It consists of a pipe 63 connected to both ends of the heat exchange part 61 for guiding a thermal energy medium 62 such as hot water, a pump 64 and a temperature control part 65 provided in the middle of the pipe 63. The temperature control section 65 controls the thermal energy key medium 62 sent from the pump 64 to a predetermined temperature and supplies it to the heat exchange section 61 .

According to this configuration, the cuvette body has the same temperature as the thermal energy medium 62 in the heat exchange section 61, and the sample in the sample tank also has the same temperature. Therefore, if this example is used to calibrate a human blood analyzer, the temperature should be set to 37
Set to ℃. In this way, the sample in the cuvette can more closely resemble human blood, and the device can be calibrated accurately.

In the above embodiments, in the light transmitting portion of the sample tank shown in FIGS. 1, 5, 6, and 8, the elastic plate 4,
In the embodiment shown in FIG. 7, the piston 50) is manually displaced, but it may also be driven by a motor. For example, in the embodiment shown in FIG. 1, a circuit in which blood circulates using a pulsating pump driven by a motor may be created, and the present cuvette may be connected in series or in parallel to the circuit.

[Effects of the Invention] According to the present invention, since the distance between the light source section and the light receiving section of the probe of the optical analyzer is kept constant, stable measurement values can be obtained (
be qed. Further, since a collimator is used, when the thickness of the sample tank is changed, the light weight received by the light receiving section can be set to a value that corresponds to the thickness of the sample tank. Furthermore, since the mask is provided, only the light from the central part of the cuvette is used for measurement, making it possible to perform highly accurate measurements.

Furthermore, we provided a means to maintain the sample temperature at a predetermined temperature.
The blood in the cuvette can be made to more closely resemble the blood in living tissue, and the optical analyzer can be calibrated accurately.

Using the present invention, optical analysis of a sample with pulsating internal pressure can be performed correctly. Further, it is possible to calibrate an optical analyzer for arterial blood using the pulsation of arterial blood within a living tissue. In addition, even for samples whose internal pressure does not pulsate, optical analysis of the sample can be performed accurately by changing the thickness of the sample tank using an external force and using the same principle as a pulse oximeter. .

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the cuvette of the present invention, Fig. 2 is a perspective view thereof, Fig. 3 is an exploded perspective view thereof, Fig. 4 is a view showing the cuvette of the present invention in use, and Figs. 5 to 8 are It is a figure which shows another Example. 1... Rigid plate 2... Mask 3... Spacer 4... Elastic plate 5... Spacer 6...
・Collimator 7...Rigid plate 15...Sample tanks 16, 17...Light transmission part 18.19...Opening part 6
1...Heat exchange section 64...Pump 65...Temperature control section agent Patent attorney Book 1) Takashi Figure 1 Figure 2 Figure 4 Figure 5 Figure 6

Claims (5)

[Claims] (1) For optical analysis used in an analyzer that receives light irradiated from a light source section through a sample at a light receiving section, and performs optical analysis of the sample based on the output of the light receiving section according to the intensity of the transmitted light. In the cuvette, a sample tank that accommodates a sample and has walls at two predetermined locations facing each other as light-transmitting sections having light-transmitting properties and is provided with an opening that serves as an entrance and exit for the sample; and the light source. a support that supports the sample tank while maintaining a constant distance between the light source section and the light receiving section, and supports the sample tank with the light source section and the light receiving section facing each other; means, when the sample tank is applied with a predetermined force, at least one of the two light transmitting parts moves toward or away from the adjacent light source part or the light receiving part, and the sample tank A cuvette for optical analysis, characterized in that the thickness of the cuvette is variable. (2) A collimator that allows only parallel light to pass is disposed between the light transmitting section on the moving side and the light source section or light receiving section adjacent to the light transmitting section.
1) The cuvette for optical analysis described above. (3) A mask is provided between the light source section and the sample tank and at least one between the light receiving section and the sample tank, and a mask is provided between the light source section and the sample tank at a predetermined distance from the light source section or the light receiving section. The cuvette for optical analysis according to claim 1 or 2, characterized in that only light that comes into contact with a predetermined area on a plane perpendicular to the optical axis connecting the light receiving section is passed through. (4) The cuvette for optical analysis according to any one of claims (1) to (3), further comprising sample temperature holding means for keeping the sample at a predetermined temperature. (5) The cuvette for optical analysis according to any one of claims (1) to (4), wherein the light transmitting part on the non-moving side is light scattering.