JP2008309805A - Light measuring instrument and light measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive light measuring instrument for accurately measuring light transmitted or reflected by an object even by a light-sensitive element with a narrow dynamic range. <P>SOLUTION: A substance quantity measuring instrument 100 is equipped with: a light source 2 for irradiating the light to a specimen placed on a specimen placement part 1; a light varying part 3 for varying intensity of the light irradiated to the specimen; an area sensor 6 for receiving the light transmitted or reflected by the specimen; and a computer 7 for outputting a state of the light intensity by the varying part 3 and a measurement result corresponding to a light quantity of the light received by the area sensor 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical measurement apparatus and an optical measurement method for irradiating an object with light and measuring light transmitted or reflected through the object.

  In a device that measures the amount of substances using optical measurement, light is radiated from a light source to an object to be placed horizontally, the reflected light is converted into an electrical signal by a light receiving element, and this is converted into a logarithm. A density value is obtained, and a substance amount is obtained from the optical density value.

  Moreover, in an optical measuring device for clinical examination, a slide in which a reagent is applied on a transparent support is used as an object to be measured, and a liquid sample such as blood is deposited on the slide, and the reaction with the reagent layer is performed. An optical density value is obtained by measuring a change in the optical density. The optical density value is converted into a clinical value, and the target analysis is performed.

  In clinical examinations and the like, it is necessary to measure optical densities of a plurality of components contained in blood. For this reason, in the optical measurement device, blood of the same person is dripped onto a plurality of slides coated with different reagents, and the above measurement is performed on all the slides (see, for example, Patent Document 1).

JP 05-018895 A

  In general, the amount of a substance is proportional to its optical density. On the other hand, the amount of light received by the light receiving element is inversely proportional to the optical density because its common logarithm is proportional to the optical density. In other words, since the amount of reflected light from each of the plurality of slides differs depending on the component to be inspected, the conventional optical measurement device has a light receiving element having a wide dynamic range that can accurately receive the reflected light from all the slides. It was necessary. Since a light receiving element having a wide dynamic range is expensive, an increase in manufacturing cost is inevitable in the conventional optical measuring device.

  The present invention has been made in view of the above circumstances, and is an inexpensive optical measurement device and optical measurement capable of accurately measuring light transmitted or reflected through an object even with a light receiving element having a narrow dynamic range. It aims to provide a method.

  An optical measurement device of the present invention includes an irradiating unit that irradiates light on an object, a light variable unit that changes an intensity of light irradiated on the object, a light receiving element that receives light transmitted or reflected by the object, Control means for controlling the light variable means to change the intensity of light applied to the object, the state of the light variable means, and the optical density of the object based on the amount of light received by the light receiving element. Output means, and the control means selects a light intensity to be used for measurement from a plurality of types of intensity in a sequence preset in accordance with the object, and selects the light of the selected intensity. The sample is irradiated.

  With this configuration, it is possible to adjust the amount of light received by the light receiving element by changing the intensity of the light irradiated to the object. Therefore, even if the dynamic range of the light receiving element is narrow, the light transmitted or reflected by the object Can be measured with high accuracy. In addition, since an inexpensive light receiving element having a narrow dynamic range can be used, the manufacturing cost of the apparatus can be reduced.

  According to the present invention, it is possible to provide an inexpensive optical measurement device that can accurately measure light transmitted or reflected through an object even with a light receiving element having a narrow dynamic range.

FIG. 1 is a diagram showing a schematic configuration of a substance amount measuring apparatus for explaining an embodiment of the present invention.
The substance amount measuring apparatus 100 includes a sample setting unit 1 for setting a sample to be measured, a light source 2 using a light emitting element such as a halogen lamp for irradiating the sample with light, and an intensity of light emitted from the light source 2. The variable light section 3 to be changed, the variable wavelength section 4 to change the wavelength of light emitted from the light source 2, the lenses 5a and 5b for collimating and collecting the light irradiated from the light source 2, and the reflection from the specimen A lens 5c for condensing light, an area sensor 6 as a light receiving element for receiving reflected light collected by the lens 5c, a state of the light variable section 3 and the light received by the area sensor 6 while controlling each part And a computer 7 for obtaining a measurement result corresponding to the amount of light and outputting the result to a display or the like. Here, the computer 7 is configured to control each unit, but a computer that performs overall control of each unit may be prepared separately.

  A slide in which a single layer of reagent is applied on a transparent support is placed in the specimen setting unit 1, and a specimen such as blood is dripped onto the slide during measurement.

  The light variable section 3 is irradiated from the light source 2 to the specimen by mechanically inserting and removing a metal mesh plate material such as stainless steel with a hole and a neutral density filter such as an ND filter between the light source 2 and the specimen. It changes the intensity of light. In the initial setting, the neutral density filter is inserted between the light source 2 and the specimen. In the following description, the metal mesh is a stainless steel mesh. Moreover, a stainless steel mesh plate with a hole and a neutral density filter such as an ND filter may be manually inserted and removed.

  The wavelength variable unit 4 changes the wavelength of light emitted from the light source 2 to the specimen by mechanically inserting or removing one of a plurality of types of interference filters between the light source 2 and the specimen. In the present embodiment, the wavelength variable unit 4 is installed between the light variable unit 3 and the specimen installation unit 1, but may be installed between the light source 2 and the light variable unit 3. Further, a plurality of types of interference filters may be manually inserted and removed.

  The area sensor 6 is a solid-state imaging device such as a CCD, and receives light reflected by light emitted from the light source 2 when a reagent on a slide installed in the sample setting unit 1 reacts with a sample such as blood. The received light is converted into an electrical signal and output to the computer 7. The area sensor 6 can receive light reflected from the slide in units of planes. For this reason, in the present embodiment, the slide is divided into a plurality of areas, different types of reagents are applied to each area, and reflected light from the reaction between the plurality of types of reagents and blood is detected by the area sensor 6. It is also possible to receive light simultaneously.

  The computer 7 converts an electrical signal corresponding to the amount of received light output from the area sensor 6 into an optical density value based on calibration curve data stored in a built-in memory or the like, and uses the optical density value as a sample. The content of various components contained in the product is obtained and output to a display or the like. As described above, when using a slide coated with a plurality of types of reagents, the computer 7 extracts an electrical signal corresponding to the amount of received light output from the area sensor 6 for each of a plurality of areas of the slide, and includes it in the specimen. The content of the ingredients to be obtained is determined for each of the multiple areas. Further, the computer 7 controls the light variable unit 3 and the wavelength variable unit 4 according to the amount of reflected light from the sample received by the area sensor 6 and the type of reagent to be reacted with the sample, and the amount of light from the light source 2 is controlled. Change the wavelength or change its wavelength.

  In the substance amount measuring apparatus 100 configured as described above, when the amount of reflected light from the specimen is so small that it does not fall within the dynamic range of the area sensor 6, the light variable section 3 moves between the light source 2 and the specimen from the stainless steel. The mesh plate or ND filter is removed, and the intensity of light emitted from the light source 2 is increased. As a result, the amount of reflected light from the specimen increases, and the amount of reflected light falls within the dynamic range of the area sensor 6. For this reason, even if the dynamic range of the area sensor 6 is narrow, the reflected light can be received with high accuracy, and the measurement accuracy of the content of the component contained in the specimen is improved.

  For example, when using a slide coated with four types of reagents A, B, C, and D, the substance amount measuring apparatus 100 obtains the amount of reflected light from each area where the reagents A to D are applied. When any of the reflected light amounts does not fall within the dynamic range of the area sensor 6, the light variable section 3 inserts and removes a stainless mesh plate or ND filter at regular intervals. In addition, since the wavelengths of light reflected from each area are different, the wavelength variable unit 4 switches a plurality of interference filters according to the wavelength.

  For example, the amount of reflected light from the area where A and B are applied is so small that it does not fall within the dynamic range of the area sensor 6, and the amount of reflected light from the area where C and D are applied falls within the dynamic range of the area sensor 6. A case where the wavelengths of light emitted when the reagents A to D react with blood are different from each other will be described.

  In this case, in the substance amount measuring apparatus 100, the light source 2 irradiates the slide with light, the reflected light from each area of the slide is received by the area sensor 6, and the reflected light amount from each area is within the dynamic range of the area sensor 6. It is determined by the computer 7 whether or not Here, since the amount of reflected light from the area where A and B are applied is so small that it does not fall within the dynamic range of the area sensor 6, the computer 7 controls the light variable section 3 after light is emitted from the light source 2 for a certain period of time. Then, the ND filter is removed from between the light source 2 and the specimen. After irradiating light for a certain time in this state, the computer 7 controls the light variable section 3 to insert an ND filter between the light source 2 and the specimen. By repeating this operation, a plurality of types of measurement components can be accurately measured with one slide.

  The computer 7 controls the optical variable unit 3, while controlling the wavelength variable unit 4 according to the types of reagents A to D, and sequentially switches the four types of interference filters. While the optical variable unit 3 removes the ND filter, the wavelength variable unit 4 alternately switches between the interference filter corresponding to the reagent A and the interference filter corresponding to the reagent B, and the optical variable unit 3 inserts the ND filter. During the operation, the interference filter corresponding to the reagent C and the interference filter corresponding to the reagent D are switched alternately. Thereby, even when the wavelengths of light emitted from a plurality of types of components contained in the specimen are different from each other, the contents of the plurality of types of measurement components contained in the specimen can be measured with one slide.

  The substance amount measuring apparatus 100 can measure with high accuracy even with a CCD having a narrow dynamic range by changing the intensity of light from the light source 2, but without changing the intensity of light, the computer 7. By changing the exposure time (receiving time of reflected light) in the CCD by controlling the above, high-accuracy measurement can be performed as described above.

  In this embodiment, the sample is irradiated with light from the light source 2 and the content of the component contained in the sample is obtained from the reflected light. However, the content of the component contained in the sample from the transmitted light that has passed through the sample. You may ask for.

  In this embodiment, reflected light from the specimen is received using an area sensor such as a CCD. However, the present invention is not limited to the area sensor, and a line sensor may be used.

  In the CCD used in this embodiment, light receiving portions such as photodiodes are arranged vertically and horizontally on a semiconductor substrate at predetermined intervals, and the light receiving portions included in adjacent light receiving portion rows are mutually within the light receiving portion row. It is desirable to use a so-called honeycomb type CCD that is shifted in the direction of about ½ row of the pitch between the light receiving portions in FIG.

  In addition, the substance amount measuring apparatus 100 is capable of accurately measuring the concentration of components contained in a specimen for an environmental substance test or a food test, as well as a biochemical test specimen such as blood. Is possible.

  In the above description, the substance amount measuring apparatus 100 changes the light intensity in real time according to the amount of reflected light from the specimen, but the measurement is performed in a sequence set in advance according to the measurement component contained in the specimen. You may make it measure the content of a component. The operation in this case will be described below.

  When the sample is set in the sample setting unit 1 and the measurement item is set, the substance amount measuring apparatus 100 starts measurement with a pattern corresponding to the measurement item. First, the computer 7 selects light intensity used for measurement from a plurality of types of intensity, and irradiates the specimen with light of the selected intensity. When the area sensor 6 receives the reflected light reflected from the specimen, the computer 7 outputs a measurement result corresponding to the amount of the reflected light received by the area sensor 6 and the intensity of the selected light. By this series of operations, it is possible to accurately measure the measurement component contained in the specimen.

  When changing the exposure time of the CCD without changing the light intensity, the substance amount measuring apparatus 100 measures the pattern according to the measurement item when the sample is set in the sample setting unit 1 and the measurement item is set. To start. First, the computer 7 irradiates the specimen with light. Then, the area sensor 6 receives the reflected light reflected from the specimen for an exposure time selected by the computer 7 from a plurality of types of exposure times. Finally, the computer 7 outputs a measurement result corresponding to the amount of reflected light received by the area sensor 6 and the selected exposure time. By this series of operations, it is possible to accurately measure the measurement component contained in the specimen.

(Example)
Hereinafter, examples of the substance amount measuring apparatus 100 will be described.
First, a method for creating calibration curve data stored in the built-in memory of the computer 7 will be described. The calibration curve data is created by using a plurality of standard density plates with known reflection optical density values, instead of slides, in the substance amount measuring apparatus 100.

The following components were used for each part constituting the substance amount measuring apparatus 100.
Area sensor 6: CCD (8 bit monochrome camera module XC-7500 manufactured by SONY Corporation)
Light source 2: Luminer Ace LA-150UX manufactured by Hayashi Clock Industry Co., Ltd.
Interference filter: Filter monochromatized to 625 nm Neutral filter: Glass filter ND-25 manufactured by HOYA Co., Ltd. and homemade filter computer 7 having a hole in a stainless mesh plate

  As the standard concentration plate, a standard concentration plate (ceramic specification) manufactured by Fuji Kikai Kogyo Co., Ltd. was used. This standard density plate is A00 having a reflection optical density of 0 to 0.05, A05 having a reflection optical density of 0.5, A10 having a reflection optical density of 1.0, A15 having a reflection optical density of 1.5, and reflection optics. Six types of A20 having a density of 2.0 and A30 having a reflection optical density of 3.0 were used.

In the following, a region of received light amount (range of received light amount of 50 to 200) that can be measured with an 8-bit monochrome CCD with high accuracy is defined as a range of a calibration curve, and a calibration curve is created according to the following flow.
(1) Using the standard density plate A00, a stainless steel plate is inserted so that the amount of reflected light from the standard density plate A00 is about 200, and the light quantity from the light source 2 is adjusted. Is used to determine the relationship between the amount of reflected light and the reflected optical density. At this time, the amount of light from the light source 2 was 96 μW / cm ² on the standard density plate.
(2) Next, the stainless steel mesh plate is removed, and the relationship between the amount of reflected light and the reflected optical density is determined using the above six types of standard density plates. At this time, the amount of light from the light source 2 was 492 μW / cm ² on the standard density plate.
(3) Graph the relationship between the amount of reflected light and the reflected optical density determined in (1) and (2) above, and create a calibration curve.

FIG. 2 is a diagram showing a calibration curve created by the above procedure.
As shown in the figure, two calibration curves are created for the case where the amount of light is large and the case where the amount of light is small. The computer 7 displays the calibration curve a in the region X (the reflection optical density of the specimen is 0 to 0.9) until the amount of reflected light from the specimen on the slide becomes less than 50 with the stainless mesh plate inserted. The calibration curve b is used in the region Y (the reflected optical density of the specimen is 0.9 to 1.8) until the amount of reflected light from the specimen on the slide becomes less than 50 with the stainless steel mesh plate removed. By using this, it is possible to measure the content of the measurement components contained in the specimen having a reflection optical density of 0 to 1.8 with high accuracy.

  Subsequently, for the three standard density plates A05, A10, and A15, the results obtained by measuring the standard deviation of the reflected optical density 10 times are shown in Table 1 below. Here, the measurement was performed using both a stainless mesh plate and an ND filter as the neutral density filter.

  As shown in Table 1, when the standard deviation of the reflection optical density of the standard density plate is obtained with the neutral density filter inserted, the reflected light quantity of A05 falls within the dynamic range of the CCD, so the standard deviation is It becomes 10 / 10,000 or less, and it can be seen that the measurement can be performed with high accuracy. However, the accuracy of A10 and A15 is not good because the amount of reflected light does not fall within the dynamic range of the CCD. Therefore, it can be seen that the accuracy is improved by removing the neutral density filter and increasing the amount of light.

  Thus, in any of the standard density plates A05, A10, and A15, a standard deviation of the reflection optical density of 10 / 10,000 or less was achieved, and the measurement was possible with high accuracy. In addition, the effect was not changed regardless of whether the ND filter or the stainless mesh plate was used. Therefore, by using a stainless steel mesh that is less expensive and less time-dependent than the ND filter, the substance amount measuring device 100 can be manufactured at a lower cost.

  Next, a quantification experiment in a clinical test was performed in a state in which calibration curve data created using a plurality of interference filters was stored in the memory of the computer 7. In this experiment, a dry clinical test used for Fuji Dry Chem Mount Slide GLU-P (measurement wavelength: 505 nm, measurement component: glucose) and TBIL-P (measurement wavelength: 540 nm, measurement component: total bilirubin) manufactured by Fuji Photo Film Co., Ltd. Each test piece of reagent is cut to about 2 mm × 4 mm, and loaded into a cell made of 5 mm × 5 mm transparent resin. From the upper part of the test piece, control serum (in this case, L 4 μL of 2 types of H) were added dropwise, and at room temperature, the measurement component in the serum was reacted with the reagent to develop a color.

  At this time, in order to calibrate the reflected optical density from the measurement component, the calibration object developed by stepwise solid exposure of the black and white photographic paper was cut into about 1.5 mm × 2 mm and four sheets (level 1 to level) 4) These were placed side by side and placed in the same field of view as the above two test pieces (CCD imageable range), and imaged with a CCD using light monochromated by an interference filter. In this case, the computer 7 receives the reflected light from the calibration object together with the reflected light from the other specimen, and performs an operation of correcting the optical density of the component contained in the other specimen based on the light quantity. In this experiment, the light quantity and wavelength of light irradiated on the slide were sequentially changed in the order shown in Table 2 below, and the reflection optical density of the calibration object was shown in Table 3.

  With respect to the measurement component having a reflected light quantity of 50 to 200 received by the CCD when light of wavelengths 505 nm and 540 nm is used with the neutral density filter inserted, the calibration curve a shown in FIG. The reflected optical density is obtained from the reflected light amount, and for the measurement component having a reflected light amount of less than 50, the reflected light using the calibration curve b shown in FIG. The concentration was determined. From the reflection optical density when the glucose and total bilirubin thus obtained are colored, and the calibration curve data stored in advance in the computer 7 in which the reflection optical density is associated with the content of the measurement component, Serum concentrations of glucose and total bilirubin were calculated. The calculation results are shown in Table 4 below.

  As shown in Table 4, since the actual measurement value and the control serum standard value are almost the same, the content of the measurement component in the serum can be accurately measured even with a CCD having a narrow dynamic range. Proved. Further, since two measurement components are measured at the same time, it is possible to perform measurement more efficiently than in the case where the two slides of GLU-P and TBIL-P are separately divided as in the prior art. In this embodiment, only two measurement components are measured. However, if two or more test pieces can be placed within the imaging range of the CCD, it is possible to simultaneously measure the concentration of two or more measurement components. is there.

  Next, with respect to the standard density plate imaged by the CCD, the reflection optical density is obtained by changing the area (measurement area) used when obtaining the reflection optical density, and the measurement is performed 10 times for each area. The standard deviation of was obtained. Here, the light from the light source 2 was monochromatized to 625 nm, and an experiment was conducted using the standard density plate A05 as a measurement target. In addition, the CCD lens system including the lens 5c was tested using both a 1 × magnification and a 0.33 × magnification. The experimental results are shown in Table 5 and Table 6 below, and FIG.

  As shown in Table 5, Table 6, and FIG. 3, when the area of the standard density plate for obtaining the reflection optical density is about 1000 pixels or more, the standard deviation of the reflection optical density becomes 10 / 10,000 or less. The measurement accuracy was found to improve. As described above, when four calibration objects and two test pieces are placed within the CCD imaging range, light is received in an area of 1000 pixels or more in each of the four calibration objects and two test pieces. By obtaining the reflection optical density based on the reflected light quantity, the measurement can be performed with higher accuracy.

The figure which shows schematic structure of the substance amount measuring apparatus for describing embodiment of this invention The figure which shows the calibration curve created with the substance amount measuring apparatus for describing embodiment of this invention The figure which shows the experimental result when changing the area | region (photometry area | region) used when calculating | requiring a reflection optical density about the standard density board imaged with CCD, and calculating | requiring a reflection optical density

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Substance amount measuring apparatus 1 Sample installation part 2 Light source 3 Light variable part 4 Wavelength variable part 5a, 5b, 5c Lens 6 Area sensor 7 Computer

Claims (16)

An irradiation means for irradiating the object with light;
A light variable means for changing the intensity of light irradiated to the object;
A light receiving element that receives light transmitted through or reflected by the object;
Control means for controlling the light variable means to change the intensity of light applied to the object;
An output means for outputting the optical density of the object based on the state of the light variable means and the amount of light received by the light receiving element;
The control means is an optical measurement device that selects light intensity used for measurement from a plurality of types of intensity in a sequence preset according to the object, and irradiates the specimen with light of the selected intensity. The optical measurement device according to claim 1,
The object has a plurality of regions with different optical densities,
The control means selects a plurality of light intensities to be used for measurement from a plurality of kinds of intensities in a pattern corresponding to a plurality of regions of the object, and selects the light with the selected plurality of intensities at regular intervals. To illuminate the object,
The output means outputs light density of the plurality of areas of the object based on the state of the light variable means and the amount of light from the plurality of areas of the object received by the light receiving element. Measuring device. The optical measurement device according to claim 1 or 2,
The light variable means is an optical measuring device that changes the intensity of the light by dimming light from the irradiation means with a plate material having a hole. The optical measurement device according to claim 3,
The optical measuring device whose said board | plate material is a metal mesh. The optical measurement device according to claim 1 or 2,
The said optical variable means is an optical measuring device which changes the intensity | strength of the said light by dimming the light from the said irradiation means with an ND filter. An irradiation means for irradiating the object with light;
A light receiving element that receives light transmitted through or reflected by the object;
Means for changing an exposure time of the light receiving element;
Control means for controlling the means for changing the exposure time to change the exposure time of the light receiving element;
An output unit that outputs the optical density of the object based on the exposure time and the amount of light received by the light receiving element;
The said control means is an optical measuring device which selects the exposure time utilized for a measurement from several types of exposure time in the sequence preset according to the said object, and makes the said light receiving element light-receive with the selected exposure time. The optical measurement device according to claim 6,
The object has a plurality of regions with different optical densities,
The control means selects a plurality of exposure times to be used for measurement from a plurality of types of exposure times in a pattern corresponding to a plurality of regions of the object, and receives the light at regular intervals within the selected plurality of exposure times. The element is made to receive light,
The output means outputs an optical density of a plurality of areas of the object based on the exposure time and the amount of light from the plurality of areas of the object received by the light receiving element. It is an optical measuring device in any one of Claims 1-7,
The object is obtained by dropping a specimen on the plurality of regions to which different reagents are applied,
The optical measurement apparatus, wherein the output means outputs an optical density corresponding to a plurality of types of measurement components of the specimen according to the reagent. The optical measurement device according to claim 1,
An optical measurement device comprising wavelength variable means for changing the wavelength of light from the irradiation means. The optical measurement device according to claim 1,
The irradiation means irradiates a plurality of calibration objects with known optical densities simultaneously with the light simultaneously with the objects,
The light receiving element receives light that has been transmitted or reflected through the calibration object,
The output means is an optical measurement device that corrects the optical density of the object based on the amount of light from the calibration object. It is an optical measuring device in any one of Claims 1-10, Comprising:
An optical measuring device in which the light receiving element is an area sensor. The optical measurement device according to claim 11,
An optical measurement device in which the area sensor is a solid-state imaging device. The optical measurement device according to claim 12,
In the solid-state imaging device, light receiving portions are arranged at predetermined intervals in the vertical and horizontal directions, and the light receiving portions included in adjacent light receiving portion rows are approximately ½ of the pitch between the light receiving portions in the light receiving portion row. An optical measuring device which is arranged to be shifted in the column direction. The optical measurement device according to claim 1,
An optical measurement device in which the object is a specimen for biochemical examination. The optical measurement device according to claim 1,
An optical measuring device in which the object is a specimen for environmental substance inspection. The optical measurement device according to claim 1,
An optical measuring device in which the object is a sample for food inspection.

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