JPH0572976B2 - - Google Patents

Description

Detailed Description of the Invention (Field of the Invention) The present invention is directed to irradiating a measurement surface of a sample with irradiation light, receiving the reflected light from the measurement surface with a light receiver having an optical sensor, and detecting the measurement surface. The present invention relates to a reflection density measuring device for measuring the reflection density of.

(Prior Art and Technical Background of the Invention) In recent years, it has become possible to quantitatively analyze specific chemical components or formed components contained in a sample liquid such as blood or urine by simply applying small droplets of the sample liquid. Dry-type chemical analysis slides that can be used for
It has been put into practical use.

In order to analyze the chemical components in a sample liquid using such a chemical analysis slide, the sample liquid is dotted onto the chemical analysis slide, and then kept at a constant temperature for a predetermined period of time in an incubator (incubator). ) to cause a coloring reaction (dye-forming reaction), and optically measure the coloring optical density. This chemical analysis slide is irradiated with measuring irradiation light containing a selected wavelength and its reflected optical density is measured, thereby quantitatively analyzing the content of the substance to be measured mainly based on the principle of colorimetry. .

The reflection optical density is measured using a reflection density measuring device. In such a reflection density measuring device, a sample, that is, the chemical analysis slide described above is mounted on the device, the measurement surface of the sample is irradiated with the measurement irradiation light, and the light reflected from the measurement surface is sent to the optical sensor. The reflection density of the measurement surface is measured by receiving the light with a light receiver.

However, when measuring reflection density using such a reflection density measuring device, the mounting accuracy of the sample,
The measurement surface of the sample deviates from the reference position for each measurement due to dimensional accuracy of the sample itself or flexural deformation of the sample. In other words, there is a risk that the measurement surface of the sample may move vertically (perpendicular to the measurement surface) from the reference position.
If the measurement surface subsequently fluctuates up and down, the positional relationship between the measurement surface and the optical sensor changes, resulting in a problem in that the measured concentration changes.

(Object of the Invention) In view of the above-mentioned circumstances, an object of the present invention is to provide a reflection density measuring device in which even if the measurement surface of a sample changes slightly up and down, the fluctuation in the measured density due to the change is extremely small.

(Structure of the Invention) In order to achieve the above object, the reflection density measuring device according to the present invention measures a sample from the center of an optical element on the measurement surface side of a light receiver that has an optical sensor that receives reflected light from the sample measurement surface. The distance r to the optical axis of the irradiation light is r ₀ , the height h from the center of the optical element to the sample measurement surface is h ₀ , and the angle θ between the optical element and the sample measurement surface is θ ₀ In this case, the above
h ₀ is an output curve showing the variation in the output of the optical sensor when h is varied under the above combination of r ₀ and θ ₀ , that is, h when r is r ₀ and θ is θ ₀ . It is characterized by being the height h (including the distance near the height h and considered to be substantially the height h) when the output takes a peak value in the output curve showing the relationship between the shall be.

That is, in the present invention, if a certain appropriate r and θ are selected, the output curve showing the relationship between h under r and θ usually becomes a parabolic curve, and at a predetermined h, the output curve shows the relationship between h and r and θ. When constructing an actual device, the r, θ, and h of the device are
By setting h to take a peak value under appropriate r and θ, even if the sample measurement surface moves up and down a little, that is, even if h fluctuates a little, the resulting output (measured concentration) will remain the same. It is characterized by being configured so that it does not fluctuate much.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a conceptual longitudinal cross-sectional view showing one embodiment of the reflection density measuring device according to the present invention.

The illustrated apparatus includes a sample holder 12 that holds a sample 10, a light source 14 that emits irradiation light suitable for measuring the reflection density of a measurement surface 10a of the sample, and a light source 14 that guides the irradiation light emitted from the light source 14 to Sample measurement surface 10
an optical fiber 1 which is made to enter perpendicularly to a
6, a condensing lens 18 that condenses the irradiation light emitted from the optical fiber 16, and an optical sensor 20 such as a silicon photodiode that receives the reflected light reflected from the sample measurement surface 10a. It consists of:

In addition, in the illustrated device, the optical fiber 1
6. When the condensing lens 18, the sample holder 12, and the optical sensor 20 are used to hold the sample 10 of regular size on the sample holder 12 in a normal state, the distance from the center 20a of the optical sensor to the measurement surface 10a of the sample is The height h up to is h ₀ , the angle θ between the measurement surface 10a of the sample and the optical sensor 20 is θ ₀ , and the center 20 of the optical sensor
They are arranged in a positional relationship such that the distance r from a to the optical axis 22 of the irradiation light is r ₀ , and furthermore, the h ₀ is determined by the combination of r ₀ and θ ₀ . The above optical sensor 20 when the above h is varied
The output curve is arranged so that h is the peak value of the output in the output curve representing the fluctuation of the output.

That is, in the optical system shown in FIG. 1, if appropriate r and θ are selected, the output curve showing the relationship between h and h under the combination of r and θ will normally be arch-shaped. A curve is formed, and the output of the optical sensor 20 reaches a peak value at a predetermined h. In the above device, r ₀ and θ ₀ are values that are appropriately selected so that the output curve showing the relationship with h becomes an arch-shaped curve, and
h ₀ is set to be the value when the output takes the peak value in the arched output curve.

An example of the above-mentioned arch-shaped output curve is shown in FIG. The curve shown in FIG.
In the optical system shown in the figure, r=8.75mm,
This shows the fluctuation state of the optical sensor output when h is varied from about 5.0 mm to about 6.5 mm under θ=45°, and the output reaches a peak value at h≈5.7 mm.

In this embodiment, as described above, h ₀ is r ₀ ,
Since the output curve under θ ₀ is set to be h when the peak value is taken, the above h may change for each measurement due to, for example, the holding accuracy of the sample by the sample holder and the dimensional accuracy of the sample itself. Even if the above h changes due to bending of the sample itself during long-term measurement, the fluctuation in the optical sensor output due to the change in h will be Δ as shown in Figure 2.
₁ , which is much smaller than the variation Δ ₂ in the case where h ₀ is other than h at the peak value of the output curve.

Note that r ₀ and θ ₀ in the above embodiment have an arch-like output curve representing the relationship with h under their combination, but r ₀ and θ ₀ in the present invention are , the output curve under these combinations may have a peak value, in other words, it may be a curve having an inflection point, and is not necessarily limited to forming an arch-shaped curve.

3 and 4 are schematic vertical cross-sectional views showing other embodiments of the reflection density measuring device according to the present invention. In these drawings, elements having the same functions as those in the embodiment shown in FIG. 1 are denoted by the same reference numerals, and explanations thereof will be omitted. The embodiment shown in FIG.
is composed of an optical sensor 20 and a lens 24 arranged on the measurement surface side of the optical sensor 20. In this embodiment, the angle θ between the measurement surface 10a of the sample and the lens 24 is set to be θ ₀ , the distance r from the center 24a of the lens 24 to the optical axis 22 of the irradiation light is set to be r ₀ , and furthermore, this Under the combination of r ₀ and θ ₀ , lens 2
The height h from the center 24a of 4 to the measurement surface 10a is set to be the height h ₀ when the output of the optical sensor 20 takes a peak value. Further, in the embodiment shown in FIG. 4, the light receiver 30 is constituted by the optical sensor 20 and an optical diaphragm 26 provided with an aperture 28 disposed on the measurement surface side of the optical sensor 20. In this embodiment, the measurement surface 10a of the sample and the aperture 26
_{The angle θ} formed _by The height h from the center 24a of the diaphragm 24 to the measurement surface 10a is set to the height _h0 at which the output of the optical sensor 20 reaches its peak value.

In these embodiments as well, the height h from the center 24a of the lens 24 or the center 26a of the diaphragm 26 to the measurement surface 10a is set to h ₀ at which the output of the sensor 20 takes the peak value, so that the chance accuracy or the change over time is Therefore, even if h changes, the fluctuation in the output of the optical sensor 20 can be minimized.
In the above embodiment, the number of light receivers is one, but it is also possible to have two or more light receivers, in which case at least one light receiver satisfies the above conditions r ₀ , It is sufficient if it is positioned below θ ₀ and h ₀ .

The reflection density measuring device according to the present invention can be modified in various ways without departing from the gist thereof, and is not limited to the embodiments described above.

(Effects of the Invention) As described above, in the reflection density measuring device according to the present invention, the r, h, and θ in the device are r ₀ , h ₀ ,
θ ₀ , and they are selected such that h ₀ is h when the output of the output curve showing the relationship with the above h under the combination of r ₀ and θ ₀ takes a peak value. However, even if the measurement surface moves up and down due to various causes, the variation in the output of the optical sensor due to the up and down movement is extremely small, and therefore, it is possible to perform more accurate measurement with less measurement density error.

[Brief explanation of the drawing]

FIG. 1 is a conceptual longitudinal cross-sectional view showing one embodiment of the device according to the present invention, FIG. 2 is a diagram showing an example of the output curve under appropriate r and θ in the embodiment device shown in FIG. 3 and 4 are schematic vertical cross-sectional views showing other embodiments of the device according to the present invention. 10...Sample, 10a...Sample measurement surface, 14...
...Light source, 20... Optical sensor, 20a... Center of optical sensor, 24... Lens, 26... Optical aperture, 3
0... Light receiver.

Claims (1)

[Scope of Claims] 1 Reflection density in which the measurement surface of a sample is irradiated with irradiation light and the reflected light reflected from the measurement surface is received by a light receiver having an optical sensor to measure the reflection density of the measurement surface. In the measuring device, the distance r from the center of the optical element on the measurement surface side of the light receiver to the optical axis of the irradiation light is r ₀ , the height h from the center of the optical element to the measurement surface is h ₀ , and The angle θ between the optical element and the measurement surface is θ ₀ , and the height h ₀ is the height h when the height h is varied under the combination of the distance r ₀ and the angle θ ₀ . A radiation concentration measuring device characterized in that the output is at a height h when the output takes a peak value in an output curve representing fluctuations in the output of the optical sensor. 2. The reflection density measuring device according to claim 1, wherein the light receiver comprises only an optical sensor. 3. The reflection density measuring device according to claim 1, wherein the light receiver comprises an optical sensor and a lens disposed on the measurement surface side of the optical sensor. 4. The reflection density measuring device according to claim 1, wherein the light receiver comprises an optical sensor and an optical aperture disposed on the measurement surface side of the optical sensor.