JP2009186365A - Optical unit, manufacturing method therefor, and water quality analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical unit manufacturing method capable of heightening measurement accuracy of water-quality analyzers. <P>SOLUTION: In the method for manufacturing optical units 10, an opening part is formed in a housing 11 for lenses with a transparent cell window 11b, and a lens 12 is housed in the housing for lenses, in such a way that the lens 12 is located close to the transparent cell window 11b, and after the optical unit 11b is heated, a tightening ring 13 is tightened to the housing 11 for lenses housing the lens 12 with a prescribed torque to fix and has the lens fixed to the housing 11 for lenses. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical unit including a lens and a transparent cell window, and a manufacturing method thereof. The present invention also relates to a water quality analyzer that includes an optical unit and analyzes water quality such as turbidity or chromaticity of water.

In order to analyze water quality such as turbidity and chromaticity, light absorbance (transmittance) and scattered light intensity are sometimes measured. In the water quality analysis, specifically, light generated by a light source is passed through a measurement cell filled with sample water, received by a light receiver, and the amount of light received is measured, thereby transmitting light. Obtain the turbidity and chromaticity by calculating the scattered light intensity.
Usually, a light source optical unit that emits light generated by a light source into the measurement cell and a light receiver optical unit that causes light that has passed through the measurement cell to enter the light receiver are attached to the measurement cell. Conventionally, as an optical unit, an optical unit including a lens that comes into contact with sample water and a housing that stores the lens has been used. In addition, as a measure for condensation and lens protection, a transparent cell window was sometimes attached to the measurement cell side. However, when a transparent cell window was attached, the effect of a decrease in measurement accuracy in water quality analysis due to temperature changes was significant. .

In general, it is known that the measurement accuracy of a water quality analyzer varies depending on a temperature change around a light source or a temperature change of sample water. For example, as the ambient temperature of the light source increases, the amount of light emitted from the light source decreases. Therefore, when the ambient temperature of the light source varies, turbidity and chromaticity vary. In addition, when the sample water includes one that changes the absorbance, such as iron or manganese, the absorbance changes when the temperature of the sample water fluctuates. Therefore, when the temperature of sample water fluctuated, turbidity and chromaticity fluctuated.
For example, in the measurement of turbidity and chromaticity of tap water using a conventional water quality analyzer, the maximum value of turbidity change due to fluctuations in environmental temperature and sample water temperature is 0.02 degrees / ° C, and the maximum value of chromaticity change is It was 0.05 degree / ° C.

In order to solve the problem, Patent Document 1 proposes a method of measuring the temperature of the sample water and adjusting the output of the light source according to the temperature of the sample water. Further, Patent Document 2 proposes a method of correcting a measurement result according to a change in environmental temperature. Patent Document 3 proposes a method in which the light source and the light receiver are supported by the same member and the temperature around the light source and the light receiver is made constant.
Japanese Utility Model Publication No. 56-117342 Japanese Utility Model Publication No. 61-143050 Japanese Patent Laid-Open No. 4-212044

However, the methods described in Patent Documents 1 to 3 cannot sufficiently solve the tendency of measurement accuracy to decrease due to changes in environmental temperature and sample water temperature.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical unit capable of increasing the measurement accuracy of a water quality analyzer and a method for manufacturing the same. It is another object of the present invention to provide a water quality analyzer with high measurement accuracy.

As a result of studying the cause of the decrease in the measurement accuracy of the water quality analyzer due to changes in the environmental temperature and the sample water temperature, the present inventor has formed a gap between the lens and the transparent cell window, and the gap causes interference. It was found that stripes were formed. Further, since the lens was loosely fixed, the position was displaced due to vibration, impact, etc., and the distance between the lens and the transparent cell window was changed, and as a result, it was found that the fringe number and shape of the interference fringes were changed. It was also found that when the temperature of the measurement environment changes, the transparent cell window expands or contracts, so that the distance between the lens and the transparent cell window changes, and as a result, the fringe number of the interference fringes changes. . Further, it has been found that when the fringe number of the interference fringes varies, the amount of light emitted into the measurement cell and the amount of light incident from the measurement cell also vary, so that the turbidity and chromaticity vary.
Based on these findings, as a result of studying means for suppressing fluctuations in measurement results, the following optical unit, manufacturing method thereof, and water quality analyzer were invented.

The present invention includes the following aspects.
[1] An optical unit comprising: a lens housing having an opening formed therein and having a transparent cell window; and a lens housed in the lens housing in the vicinity of the transparent cell window,
In the lens, the fringe number of interference fringes formed by a gap between the transparent cell window is 10 or more at 40 ° C., and the variation rate at −5 to 60 ° C. is within ± 50%. An optical unit fixed to a lens housing.
[2] A method of manufacturing an optical unit in which an opening is formed and a lens is housed in a lens housing having a transparent cell window so as to be close to the transparent cell window,
A method for manufacturing an optical unit, comprising: heating a transparent cell window; and tightening a tightening ring to a lens housing that houses a lens with a predetermined torque to fix and store the lens in the lens housing.
[3] A method of manufacturing an optical unit in which an opening is formed and a lens is housed in a lens housing having a transparent cell window so as to be close to the transparent cell window,
When the lens is fixedly stored, the fringe number of the interference fringes formed by the gap between the transparent cell window is 10 or more at 40 ° C., and the variation rate at −5 to 60 ° C. is ± A method of manufacturing an optical unit, wherein a lens is fixedly housed in a lens housing so that it is within 50%.
[4] The method for manufacturing an optical unit according to [3], wherein the lens is fixed to the lens housing after the transparent cell window is heated.
[5] A measurement cell filled with sample water, a light source, a light receiver, a light source optical unit that emits light generated by the light source into the measurement cell, and a light receiver that passes through the measurement cell An optical unit for a receiver to be incident on
One or both of the optical unit for light source and the optical unit for light receiver are optical units manufactured by the method for manufacturing an optical unit according to any one of [2] to [4], and the transparent cell window of the optical unit is A water quality analyzer, which is arranged so as to be in contact with sample water in a measurement cell.
[6] A light source unit temperature measurement device that measures the ambient temperature of the light source and a calculation unit are further provided, and the calculation unit analyzes the water quality based on the ambient temperature of the light source measured by the light source unit temperature measurement device. The water quality analyzer according to [5], wherein the measured value is corrected.
[7] A sample water temperature measuring device for measuring the temperature of the sample water and a calculation unit are further provided. In the calculation unit, measurement of water quality analysis is performed based on the temperature of the sample water measured by the sample water temperature measuring device. The water quality analyzer according to [5] or [6], wherein the value is corrected.

The optical unit of the present invention can increase the measurement accuracy of the water quality analyzer.
According to the method for manufacturing an optical unit of the present invention, an optical unit capable of increasing the measurement accuracy of a water quality analyzer is obtained.
The water quality analyzer of the present invention has high measurement accuracy.

<Optical unit>
An embodiment of the optical unit of the present invention will be described.
FIG. 1 shows an optical unit of this embodiment. The optical unit 10 of the present embodiment includes a lens housing 11 (hereinafter abbreviated as “housing 11”), one lens 12 housed in the housing, and a tightening ring 13 for fixing the lens 12. .

(housing)
The housing 11 accommodates the lens 12, and includes a housing body 11a in which openings 11c and 11d (see FIG. 2) are formed, and a transparent cell window 11b attached to the housing body 11a so as to close the opening 11c. Have
The inner diameter of the housing body 11 a is larger than the diameter of the lens 12.
Moreover, as shown in FIG. 2, the thread groove 11e is formed in the opening part 11d side which is the edge part side to which the transparent cell window 11b is not attached of the internal peripheral surface of the housing main body 11a.

The transparent cell window 11b in the present embodiment is plate-shaped, and its diameter is substantially the same as the outer diameter of the housing body 11a.
The material of the transparent cell window 11b may be either glass or transparent resin, but transparent resin is preferred from the viewpoint of workability and impact resistance. Examples of the transparent resin used for the transparent cell window 11b include acrylic resin, polycarbonate, polystyrene, styrene-acrylic copolymer, and polycycloolefin. Among these, acrylic resin is preferable from the viewpoint of optical characteristics, moldability, and price.

(lens)
The lens 12 is disposed close to the transparent cell window 11b, the surface on the transparent cell window 11b side is a convex surface, and the opposite surface is a flat surface. The lens 12 is fixed to the housing body 11a so that a gap is formed between the transparent cell window 11b.

(Tightening ring)
The tightening ring 13 has a thread groove 13 a formed on the outer peripheral surface, and a recess 13 b formed on the lens 12 side in which the lens 12 is fitted.
Here, the screw groove 13a corresponds to the screw groove 11e of the housing body 11a. Therefore, the tightening ring 13 can be screwed to the housing body 11a.

(Fixing of lens and transparent cell window)
The lens 12 has a variation rate of a fringe number of interference fringes formed by a gap between the lens 12 and the transparent cell window 11b at a constant temperature within ± 50%, preferably within ± 30%, more preferably within ± 10%. It is being fixed to the housing main body 11a so that it may become. Here, the fluctuation rate of the number of fringes at −5 to 60 ° C. is a value obtained by (number of fluctuations of fringe number) / (number of fringes before fluctuation) × 100 (%). Moreover, -5-60 degreeC is the range of the external temperature in case the optical unit 10 is normally used.

In order to reduce the influence of fluctuation of the fringe number of interference fringes, the initial fringe number of interference fringes (that is, immediately after the lens 12 is fixed to the housing 11) is set to 10 or more at 40 ° C. Here, 40 ° C. is slightly higher than the temperature around the optical unit when the optical unit is normally used (for example, the temperature inside the analyzer). The fringe number is a value when counted under natural light.
If the initial fringe number of the interference fringes is as large as 10 or more, even if the fringe number of the interference fringes fluctuates due to a temperature change, the fluctuation ratio with respect to the fringe number of the interference fringes before the fluctuation becomes small. The effect of fluctuations in the number of fringes is reduced. Therefore, fluctuations in measurement results can be further suppressed.

The fringe number of the interference fringes varies depending on the thermal expansion of the transparent cell window 11b.
For example, when the transparent cell window 11b is made of an acrylic resin, it has a thermal expansion coefficient of about 0.7 mm / m per 10 ° C. If the initial thickness of the transparent cell window 11b is 1 mm and the environmental temperature changes by 40 ° C., the thickness of the transparent cell window 11b changes by 2.8 μm. Therefore, the distance between the transparent cell window 11b and the lens 12 changes under the influence of temperature, and the fringe number of the interference fringes changes.

(Function and effect)
In the optical unit 10 described above, the lens 12 is fixed to the housing body 11a so that the fringe number of interference fringes is 10 or more at 40 ° C., and the variation rate at −5 to 60 ° C. is within ± 50%. Since it is difficult to be displaced due to vibration or impact, it is possible to suppress a decrease in measurement accuracy due to fluctuations in the fringe number and shape of interference fringes. Also, when the lens 12 is fixed by increasing the fringe number of interference fringes, the influence of fluctuations in the fringe number of interference fringes due to changes in the environmental temperature can be reduced. Therefore, the water quality analyzer using the optical unit 10 can sufficiently suppress the variation in the measurement result due to the relative variation in the fringe number of the interference fringes, and can increase the measurement accuracy.
Such an optical unit 10 can be used as an optical unit attached to a light source such as a light emitting diode or an optical unit attached to a light receiver.

<Optical unit manufacturing method>
An embodiment of a manufacturing method for manufacturing the optical unit 10 will be described.
In the manufacturing method of the optical unit 10 of this embodiment, first, the transparent cell window 11b is attached to the housing body 11a so as to close the opening 11c.
As a method of attaching the transparent cell window 11b, for example, a method of adhering with an adhesive, a method of adhering by heat welding or ultrasonic welding, or the like can be applied.
Next, the lens 12 is housed in the housing main body 11a, and the lens 12 is fitted into the recess 13b of the tightening ring 13, and the tightening ring 13 is screwed into the housing main body 11a, thereby pushing the lens 12 toward the transparent cell window 11b. .

  The tightening torque for screwing the tightening ring 13 to the housing body 11a is appropriately selected depending on the number of fringes of interference fringes to be formed, the size, material and shape of the transparent cell window 11b, the curvature of the lens 12, and the like. For example, when the material of the transparent cell window 11b is acrylic resin and the thickness of the transparent cell window 11b is 1 mm, in order to form 10 or more interference fringes, the tightening torque may be 15 cN · m or more. In terms of preventing breakage, the tightening torque is preferably 30 cN · m or less.

When the fastening ring 13 is screwed to the housing body 11a and the lens 12 is fixed to the housing body 11a, the lens 12 is previously stored in the housing body 11a and the fastening ring 13 is loosely screwed, that is, Although it is preferable to heat the optical unit 10 in a temporarily assembled state, at least the transparent cell window 11b is heated. Heating the transparent cell window 11b can cause thermal expansion. After tightening the tightening ring 13 with a predetermined torque with the transparent cell window 11b thermally expanded to push the lens 12, the housing body 11a and the transparent cell window 11b are contracted to the original shape by cooling to room temperature. The gap between the lens 12 and the transparent cell window 11b is kept constant.
The method of fixing the lens 12 and the transparent cell window 11b by heating in this way is particularly suitable when the transparent cell window 11b is made of a resin having a large thermal expansion coefficient.

The heating temperature and heating time in the heating are appropriately selected according to the materials of the housing body 11a and the transparent cell window 11b and the ambient temperature at the time of use.
When the material of the transparent cell window 11b is an acrylic resin, the heating temperature is preferably 30 ° C. or higher. If the heating temperature is 30 ° C. or higher, the gap between the lens 12 and the transparent cell window 11b can be further widened when cooled to room temperature, and the fringe number of interference fringes can be increased more easily.
Moreover, it is preferable that heating temperature is 60 degrees C or less. If heating temperature is 60 degrees C or less, the irreversible deformation | transformation by plasticization of the transparent cell window 11b can be prevented.
The heating time is preferably 30 minutes or longer. If the heating time is to some extent, heat can be transferred to the inside of the housing main body 11a and the transparent cell window 11b, and the heat can be sufficiently expanded, the inside can be homogenized, and the shape of the fringe can be stabilized. it can.

After the tightening ring 13 is screwed to the housing main body 11a with a predetermined torque, the tightening ring 13 is fixed to the housing main body 11a with an adhesive so that the screwing position does not shift.
In this way, the optical unit 10 is obtained in which the lens 12 is fixed to the housing body 11a so that the fringe number and shape of the interference fringes do not vary.

  In the optical unit manufacturing method described above, the transparent cell window 11b is heated, and then the fastening ring 13 is fastened to the housing body 11a with a predetermined torque to fix the lens 12 to the housing body 11a. However, it is difficult to shift the position, and a decrease in measurement accuracy due to fluctuations in the fringe number and shape of the interference fringes can be suppressed. In addition, when the number of interference fringes is increased and the lens 12 is fixed, the influence of fluctuations in the fringe number of the interference fringes due to changes in the environmental temperature can be reduced. Therefore, in the water quality analyzer using the optical unit 10 obtained by this manufacturing method, fluctuations in the measurement result due to fluctuations in the fringe number and shape of the interference fringes can be sufficiently suppressed, and the measurement accuracy can be increased.

<Water quality analyzer>
An embodiment of the water quality analyzer of the present invention will be described.
FIG. 3 shows the water quality analyzer of this embodiment. The water quality analyzer 1 of the present embodiment is a turbidity analyzer, and the measurement cell 20 filled with sample water, the light source 30, the light receiver 40, and the light generated by the light source 30 in the measurement cell 20. The light source optical unit 10a to be emitted, the light receiver optical unit 10b for causing the light passing through the measurement cell 20 to enter the light receiver 40, and the light emitted from the light source optical unit 10a to be reflected toward the light receiver optical unit. And a calculating unit 60 that obtains turbidity based on the amount of light received by the light receiver 40.
In addition, the water quality analyzer 1 of the present embodiment includes a light source unit temperature measuring device 70 that measures the temperature around the light source 30 and a sample water temperature measuring device 80 that measures the temperature of the sample water. Here, the light source unit refers to the light source 30 and an accessory device around the light source 30.

The measurement cell 20 in the water quality analyzer 1 of this embodiment includes a bottomed cylindrical cell body 21 filled with sample water, an introduction part 22 for introducing the sample water into the cell body 21, and the cell body 21. And a discharge portion 23 for discharging the sample water. Here, the introduction part 22 is provided below the peripheral surface of the measurement cell 20, and the discharge part 23 is provided above the peripheral surface of the measurement cell 20.
In the present embodiment, both the light source optical unit 10 a and the light receiver optical unit 10 b are the optical unit 10 described above, and the transparent cell windows 11 f and 11 g are in contact with the sample water in the measurement cell 20. It is installed on the peripheral surface of the cell body 21.
As the light source 30, a light emitting diode is used. The wavelength of light emitted from the light source 30 for measuring turbidity is, for example, 660 nm.
As the light receiver 40, a photodiode corresponding to the wavelength of light to be received is used.

  In this embodiment, the periphery of the light source 30 and the light source optical unit 10a and the periphery of the light receiver 40 and the light receiver optical unit 10b are covered with a heat insulating material. Abrupt temperature changes are prevented from occurring due to the covering of the heat insulating material. Although there is no restriction | limiting in particular as a heat insulating material, Since the heat conductivity is low and it is excellent in heat insulation, the thing made from a fluororesin is preferable.

In the calculation unit 60, the amount of received light measured by the light receiver 40 is input, and based on the amount of received light, the transmittance of light generated by the light source 30 is obtained to obtain turbidity.
By the way, in general, the light emission amount of the light source varies depending on the ambient temperature of the light source (specifically, the higher the ambient temperature of the light source, the smaller the light emission amount). Therefore, accurate turbidity cannot be obtained. Sometimes. However, in the calculation unit 60 of the present embodiment, the light emission amount of the light source 30 corresponding to the temperature is stored in advance, and the ambient temperature of the light source measured by the light source unit temperature measuring device 70 is input, and the ambient temperature The turbidity can be corrected in consideration of the light emission amount change of the light source 30 due to the change.
The sample water may contain ions that affect turbidity measurement. When such ions are contained in the sample water, the absorbance of the sample water may change due to a change in the temperature of the sample water, and the turbidity may vary. However, in the calculation unit 60 of the present embodiment, data obtained by measuring the absorbance of the same sample water while changing the temperature is stored in advance, and the sample water temperature measured by the sample water temperature measuring device 80 is input. The turbidity can be corrected in consideration of changes in absorbance due to changes in the sample water temperature.

  In the water quality analyzer 1, first, sample water is introduced from the introduction unit 22 into the cell body 21 and is discharged from the discharge unit 23 to flow. Thus, the light emitted from the light source 30 in a state where the sample water is flowed is sequentially passed through the lens 12 of the light source optical unit 10a and the transparent cell window 11f, and is emitted into the cell body 21 of the measurement cell 20. The light emitted from the light source optical unit 10a passes through the sample water in the cell main body 21, is reflected by the reflecting mirror 50, passes through the sample water again, and passes through the transparent cell window 11g and the lens 12 of the light receiver optical unit 10b. And sequentially enter the light receiver 40. Then, since the received light amount of the incident light is measured by the light receiver 40, the light transmittance is obtained by the calculation unit 60 based on the received light amount, and the turbidity is obtained. At this time, the calculation unit 60 corrects the turbidity value to be calculated in consideration of the change in the light emission amount of the light source 30 due to the change in the environmental temperature and the change in absorbance due to the temperature change in the sample water.

In the water quality analyzer 1 described above, since the lens 12 includes the light source optical unit 10a and the light receiver optical unit 10b fixed to the housing body 11a, fluctuations in measurement results due to fluctuations in the fringe number and shape of interference fringes. Can be sufficiently suppressed, and the measurement accuracy can be increased.
Moreover, the calculation unit 60 corrects the turbidity in consideration of the change in the light emission amount of the light source 30 due to the change in the environmental temperature and the change in absorbance due to the change in the temperature of the sample water.
In addition, the light source unit temperature measuring device 70 and the calculation unit 60 grasp the light emission amount change of the light source 30 due to the environmental temperature change and reflect the result on the turbidity, so that the temperature around the light source 30 is kept constant. Thus, it is not necessary to adjust the temperature. By not adjusting the ambient temperature of the light source 30, condensation of the optical unit can be prevented and power consumption can be reduced. Moreover, when a desiccant is provided, the lifetime of a desiccant can be extended.

In addition, this invention is not limited to the said embodiment. For example, in the water quality analyzer of the present invention, only one of the light source optical unit 10a and the light receiver optical unit 10b may be the optical unit of the present invention.
Further, in the present invention, the light source temperature measuring device 70 is not provided, and the measurement result variation due to the light source temperature variation need not be corrected.
In the present invention, the sample water temperature measuring device 80 is not provided, and the measurement result variation due to the sample water temperature variation need not be corrected.
The light source optical unit 10a, the light receiver optical unit 10b, the light source 30, and the light receiver 40 may not be covered with a heat insulating material.
The water quality analyzer may be a chromaticity analyzer. The chromaticity can be measured by changing the wavelength of light generated by the light source 30 to, for example, 370 nm.

Moreover, the water quality analyzer 1 does not need to be equipped with the reflective mirror 50, In that case, scattered light can be measured. In the case of absorbance measurement, the reflecting mirror 50 is unnecessary if the light source optical unit 10a and the light receiver optical unit 10b are arranged at opposing positions.
The arrangement of the light source optical unit 10a and the light receiver optical unit 10b with respect to the measurement cell 20 is not particularly limited as long as the transparent cell windows 11f and 11g are in contact with each other and an optical path is secured. For example, an optical unit for a light source is attached to one end of a tubular measurement cell so that the transparent cell window is in contact with the liquid, and an optical unit for a light receiver is attached to the other end of the measurement cell so that the transparent cell window is in contact with the liquid. It may be.
Furthermore, the shape of the measurement cell 20 is not limited to a cylindrical shape.
The light source 30 and the light receiver 40 may be housed in the housing body 11a of the optical units 10a and 10b.

In the optical unit of the above embodiment, the housing main body 11a and the transparent cell window 11b are separately formed and then attached by an adhesive or the like, but the housing main body 11a and the transparent cell window 11b are integrally formed. It may be formed. Moreover, although the lens 12 was fixed by screwing the fastening ring 13 to the housing main body 11a, it may be fixed by other methods. For example, the lens 12 may be fixed only with an adhesive without using the tightening ring 13.
Furthermore, although the optical unit of the above embodiment includes one lens, a plurality of lenses, for example, two, three, four, etc., may be used.

Using the water quality analyzer shown in FIG. 3, changes in turbidity and chromaticity with respect to changes in environmental temperature and sample water temperature were measured using tap water as a sample to be measured. As described above, the light source optical unit 10a and the light receiver optical unit 10b in the water quality analyzer 1 are the lens units shown in FIG. The light source optical unit 10a and the light receiver optical unit 10b fixed the lens 12 by heating the transparent cell window 11b at 40 ° C. for 3 hours or more and then tightening the tightening ring 13 to the housing body 11a with a torque of 15 cN · m. Is. Further, the wavelength of light in the measurement of turbidity is 660 nm, and the wavelength of light in the measurement of chromaticity is 370 nm.
In the water quality analyzer of this example, as shown in FIGS. 4 and 5, the maximum value of turbidity change was 0.006 degrees / ° C., and the maximum value of chromaticity change was 0.043 degrees / ° C. This is sufficiently small with respect to full scale (turbidity: 0 to 4 degrees, chromaticity: 0 to 20 degrees), and smaller than the value of the conventional water quality analyzer (the maximum value of turbidity change is The maximum value of the change in chromaticity was 0.05 degrees / ° C. Therefore, it was confirmed that high measurement accuracy could be obtained even if the environmental temperature or the sample water temperature fluctuated.

It is sectional drawing which shows one Embodiment of the optical unit of this invention. It is sectional drawing which shows the housing which comprises the optical unit shown in FIG. It is a schematic diagram which shows one Embodiment of the water quality analyzer of this invention. It is a graph which shows the measurement result of turbidity in an Example. It is a graph which shows the measurement result of chromaticity in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water quality analyzer 10, 10a, 10b Optical unit 11 Housing 11a Housing main body 11b, 11f, 11g Transparent cell window 11c, 11d Opening part 11e Screw groove 12 Lens 13 Tightening ring 13a Screw groove 13b Recess 20 Measurement cell 21 Cell main body 22 Introduction Section 23 Discharge section 30 Light source 40 Light receiver 50 Reflector 60 Calculation section 70 Light source section temperature measuring instrument 80 Sample water temperature measuring instrument

Claims (7)

An optical unit comprising: a lens housing having an opening formed therein and having a transparent cell window; and a lens housed in the lens housing adjacent to the transparent cell window,
In the lens, the fringe number of interference fringes formed by a gap between the transparent cell window is 10 or more at 40 ° C., and the variation rate at −5 to 60 ° C. is within ± 50%. An optical unit fixed to a lens housing. A method of manufacturing an optical unit in which an opening is formed and a lens is housed in a lens housing having a transparent cell window so as to be close to the transparent cell window,
A method for manufacturing an optical unit, comprising: heating a transparent cell window; and tightening a tightening ring to a lens housing that houses a lens with a predetermined torque to fix and store the lens in the lens housing. A method of manufacturing an optical unit in which an opening is formed and a lens is housed in a lens housing having a transparent cell window so as to be close to the transparent cell window,
When the lens is fixed and stored, the fringe number of interference fringes formed by the gap between the transparent cell windows is 10 or more at 40 ° C., and the variation rate at −5 to 60 ° C. is ± 50%. A method of manufacturing an optical unit, wherein the lens is fixedly housed in a lens housing so as to be within the range.   The method of manufacturing an optical unit according to claim 3, wherein the lens is fixed to the lens housing after the transparent cell window is heated. A measurement cell filled with sample water, a light source, a light receiver, a light source optical unit that emits light generated by the light source into the measurement cell, and light that has passed through the measurement cell is incident on the light receiver. An optical unit for the receiver,
One or both of the optical unit for light source and the optical unit for light receiver is an optical unit manufactured by the method for manufacturing an optical unit according to any one of claims 2 to 4, and the transparent cell window of the optical unit is a measurement cell. The water quality analyzer is arranged so as to be in contact with the sample water inside.   A light source temperature measuring device for measuring the ambient temperature of the light source; and a computing unit, wherein the computing unit measures the water quality analysis based on the ambient temperature of the light source measured by the light source temperature measuring device. The water quality analyzer according to claim 5, wherein   A sample water temperature measuring device for measuring the temperature of the sample water and a calculation unit are further provided, and the calculation unit corrects the measured value of the water quality analysis based on the temperature of the sample water measured by the sample water temperature measuring device. The water quality analyzer according to claim 5 or 6.

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