JP5573776B2 - Oxygen concentration measuring device - Google Patents

Description

  The present invention relates to an oxygen concentration measuring apparatus, and in particular, a fluorescent paint is applied to a measurement target region, and fluorescence is generated by irradiating excitation light on the fluorescent paint surface, and the fluorescent intensity distribution is photographed, thereby measuring the measurement target. The present invention relates to an oxygen concentration measurement device that measures an oxygen concentration distribution in a region.

In recent years, global environmental problems have been greatly highlighted. A fuel cell not only has high energy conversion efficiency but also contributes to the reduction of CO ₂ emissions, and is also a clean cell that emits almost no NOx, SOx, dust, etc. that cause acid rain and air pollution. It is. Furthermore, there is an advantage that silence is also high. Therefore, some fuel cells are being put into practical use as an energy conversion device that is optimal for the 21st century. In particular, a polymer electrolyte fuel cell (PEFC) among fuel cells has an advantage that it can be miniaturized because of its low operating temperature and high output density.

FIG. 4 is a cross-sectional view showing an example of a polymer electrolyte fuel cell.
The solid polymer fuel cell has a configuration in which a polymer solid electrolyte membrane 101 is sandwiched between an oxygen electrode 102 and a hydrogen electrode 103. The polymer solid electrolyte membrane 101 is, for example, an ion exchange membrane obtained by applying a slurry containing a polymer solid electrolyte on a carbon fiber porous cloth substrate and then baking the slurry. The outside of the oxygen electrode 102 is carried on the current collector 106, and the outside of the hydrogen electrode 103 is carried on the current collector 107.

  The outer peripheral edge of the oxygen electrode 102 is in contact with the inside of the frame-shaped gasket 104, and the outer peripheral edge of the gasket 104 is in contact with the protruding peripheral edge of the separator plate 108 having a plurality of recesses inside. Yes. Thus, a plurality of oxygen electrode chambers 109 are formed between the inside of the separator plate 108 and the outside of the oxygen electrode 102 so as to correspond to the plurality of recesses. The separator plate 108 includes an oxygen gas supply port 112 connected to the oxygen electrode chamber 109 so as to penetrate the inner side and the outer side, and an unreacted oxygen gas connected to the oxygen electrode chamber 109 so as to penetrate the inner side and the outer side. And a generated water outlet 113.

  On the other hand, the outer periphery of the hydrogen electrode 103 is in contact with the inside of the frame-shaped gasket 105, and the outer periphery of the gasket 105 is in contact with the protruding periphery of the separator plate 110 having a plurality of recesses on the inside. doing. Thus, a plurality of hydrogen electrode chambers 111 are formed between the inside of the separator plate 110 and the outside of the hydrogen electrode 103 so as to correspond to the plurality of recesses. The separator plate 110 includes a hydrogen gas supply port 114 connected to the hydrogen electrode chamber 111 so as to penetrate the inner side and the outer side, and an unreacted hydrogen gas connected to the hydrogen electrode chamber 111 so as to penetrate the inner side and the outer side. And an outlet 115.

  Next, the operation of the polymer electrolyte fuel cell will be described. When hydrogen flows through the plurality of hydrogen electrode chambers 111 in order from the hydrogen gas supply port 114 and oxygen flows through the plurality of oxygen electrode chambers 109 in turn from the oxygen gas supply port 112, hydrogen is converted into hydrogen ions by the hydrogen electrode 103. Separated into electrons. Hydrogen ions generated at the hydrogen electrode 103 selectively permeate the polymer solid electrolyte membrane 101. The permeated hydrogen ions react with oxygen at the oxygen electrode 102 to become water. At this time, electrons generated at the hydrogen electrode 103 flow from the hydrogen electrode 103 toward the oxygen electrode 102 through an external load (not shown). That is, current flows to the external load.

  By the way, in order to spread the polymer electrolyte fuel cell, it is necessary to solve various technical problems including cost. For example, since the polymer performance of a solid polymer fuel cell deteriorates with the passage of operating time, the battery life associated with the deterioration is an important issue. In order to solve such a technical problem, how oxygen flows from the oxygen gas supply port 112 to the plurality of oxygen electrode chambers 109 and how it reacts in the plurality of oxygen electrode chambers 109 is determined. It is necessary to analyze.

  Therefore, an oxygen concentration measurement method for measuring the oxygen concentration distribution of the plurality of oxygen electrode chambers 109 has been disclosed (see, for example, Patent Document 1). In such an oxygen concentration measurement method, the separator plates 108 of the plurality of oxygen electrode chambers 109 to be measured regions are made of a transparent material, and a ruthenium complex paint (fluorescent paint) is sprayed or brushed on the separator plate 108. A simulated fuel cell coated by using this is produced. Then, the fluorescent paint surface is irradiated with excitation light (wavelength 470 nm) to generate fluorescence (about 600 nm), and this fluorescence intensity distribution is photographed. At this time, the fluorescent paint surface generates fluorescence by excitation light, but the fluorescence is quenched by oxygen at a location where the oxygen concentration is high. Thereby, the oxygen concentration distribution of the plurality of oxygen electrode chambers 109 can be measured based on the photographed fluorescence intensity distribution.

Furthermore, an oxygen concentration measuring apparatus for using such an oxygen concentration measuring method has been developed. FIG. 3 is a schematic configuration diagram showing an example of a conventional oxygen concentration measuring apparatus.
The oxygen concentration measurement device 51 includes a light irradiation unit 10, an imaging unit 20, an arrangement unit 30 on which an inspection object S to which a fluorescent paint is applied is arranged, and a computer 90 that controls the entire oxygen concentration measurement device 51. Prepare. One direction horizontal to the ground is defined as an X direction, a direction horizontal to the ground and perpendicular to the X direction is defined as a Y direction, and a direction perpendicular to the X direction and the Y direction is defined as a Z direction.

The light irradiation unit 10 includes a laser light source 15 that emits excitation light (wavelength 470 nm), an electronic shutter 12, a diffusion filter 13, a lens 14, a power meter 11 that detects the intensity I of the excitation light, and excitation light. And a half mirror 16 divided in two directions.
In such a configuration of the light irradiation unit 10, the excitation light emitted from the laser light source 15 is divided into two directions by the half mirror 16. One of the two directions in which the excitation light divided by the half mirror 16 travels passes through the electronic shutter 12, the diffusion filter 13, and the lens 14 in this order, and the measurement target region of the placement unit 30. It comes to be irradiated. On the other hand, the intensity I of the remaining one of the two directions in which the excitation light divided by the half mirror 16 travels is detected by the power meter 11.
The laser light source 15 can adjust the intensity I of the excitation light to be emitted and is controlled by a control signal from the computer 90.

The imaging unit 20 includes a high-speed photographing camera (imaging device) 21 having a lens 21a. The high-speed photographing camera 21 has a plurality of light detection elements arranged in a row direction and a column direction, and fluorescence of a luminance value corresponding to each position is incident on each light detection element. Therefore, the output signal of each photodetecting element represents the luminance value of the fluorescence for each position of the measurement target region of the placement unit 30.
The high-speed photographing camera 21 can adjust the aperture value F and the exposure time T, and is controlled by a control signal from the computer 90.

  Further, in order to irradiate the inspection object S with the excitation light from the X direction and detect the fluorescence traveling in the −X direction, a flat plate-shaped mirror 31 that transmits the excitation light and reflects the fluorescence is disposed. Thereby, the excitation light traveling in the X direction passes through the mirror 31 and is irradiated to the measurement target region of the placement unit 30, and the fluorescence generated in the measurement target region of the placement unit 30 travels in the −X direction. Thus, the traveling direction is changed by the mirror 31, and the traveling direction is further changed by the mirror 32 so as to be incident on the high-speed photographing camera 21.

  The computer 90 includes a CPU (control unit) 91 and a memory (storage unit) 94, and a monitor (display device) 42 and an operation unit (input device) 43 are connected to each other. Further, the functions processed by the CPU 91 will be described in a block form. The CPU 91 includes a light source control unit 91 a that controls the laser light source 15 and an imaging device control unit 91 b that controls the high-speed photographing camera 21.

When the desired aperture value F and the desired exposure time T are input from the operation unit 43, the imaging device control unit 91b controls the high-speed imaging camera 21 so that the input aperture value F and the exposure time T are obtained. Thereafter, control for acquiring a fluorescence intensity distribution image from the high-speed photographing camera 21 is performed.
When the desired intensity I of the excitation light is input from the operation unit 43, the light source controller 91a is configured to be a laser light source based on the intensity I detected by the power meter 11 so that the intensity I of the input excitation light is obtained. 15 is controlled.

JP 2006-331733 A

By the way, in order to acquire a fluorescence intensity distribution image with the oxygen concentration measuring apparatus 51 as described above, it is necessary to appropriately adjust the aperture value F, the exposure time T, the intensity I of excitation light, and the like of the high-speed photographing camera 21.
For example, regarding the adjustment of the aperture value F of the high-speed camera 21, it is desired to secure the necessary depth of focus d and open the aperture value F as much as possible to brighten the acquired image.

Regarding the adjustment of the exposure time T of the high-speed photographing camera 21, it is desired that the maximum luminance value obtained when the fluorescent paint surface is not quenched by oxygen is, for example, about half the luminance value that can be photographed.
Furthermore, regarding the adjustment of the intensity I of the excitation light, when the fluorescent paint is irradiated with excitation light having a strong intensity I, the luminance value of the fluorescence increases, but the fluorescent paint itself may be deteriorated by the excitation light, and the intensity is as weak as possible. I want to irradiate I excitation light.

However, it takes time to appropriately adjust the aperture value F, the exposure time T, the excitation light intensity I, and the like of the high-speed photographing camera 21, and the adjusted value may differ depending on the user.
SUMMARY OF THE INVENTION An object of the present invention is to provide an oxygen concentration measuring apparatus that can easily adjust the aperture value F, exposure time T, excitation light intensity I, and the like of a high-speed photographing camera.

The oxygen concentration measuring device of the present invention made to solve the above-mentioned problems is a light irradiation unit having a light source that irradiates excitation light to a measurement target region to which a fluorescent paint having an oxygen quenching property is applied, and the measurement target An imaging unit having an imaging device that captures the fluorescence intensity distribution of the fluorescent paint surface applied to the region, and a control unit that measures the oxygen concentration distribution of the measurement target region based on the fluorescence intensity distribution, it becomes possible to adjust the aperture value F and an exposure time T of the image pickup device of the apparatus, an oxygen concentration measuring device capable of adjusting the intensity I of the excitation light emitted from the light source, the a storage unit for storing the initial intensity I _s of the exciting light emitted from the light source, further comprising an input device input operation is performed, the control unit, the fluorescence intensity of the fluorescent paint surface by the measurer by the input device Min By inputting the depth of focus d that ensures the acquisition of the cloth image, the aperture value F of the imaging device is set using the relational expression between the depth of focus d and the aperture value F, and the input device in the measurement time interval t which is input by the measurer as the initial exposure time T _S of the image pickup apparatus, when the luminance value of the captured fluorescence intensity distribution image is high, to change the exposure time T of the image pickup device, On the other hand, when the luminance value of the fluorescence intensity distribution image is low, the intensity I of the excitation light is changed .

Here, as the “fluorescent paint having oxygen quenching properties”, for example, a polymer material having oxygen permeability such as polystyrene is used as a binder, and the dye reacts with ultraviolet to blue excitation light such as platinum porphyrin or ruthenium. And the like using a material that emits light and has an oxygen quenching property.
The “measurement time interval” refers to a measurement time interval (time resolution) of the oxygen concentration distribution to be measured.

According to the oxygen concentration measuring apparatus of the present invention, when the depth of focus d and the measurement time interval t are input by the input device, for example, using the relational expression between the depth of focus d and the aperture value F, the depth of focus d is expressed in the relational expression. By substituting, the aperture value F is automatically set. Further, based on the luminance value of the fluorescence intensity distribution image captured by the initial exposure time interval T _S of the image pickup apparatus the measurement time interval t which is input by the input device, the exposure time T is automatically in the imaging apparatus Is set.

  As described above, according to the oxygen concentration measuring apparatus of the present invention, the aperture value F and the exposure time T of the high-speed camera can be easily adjusted.

(Means and effects for solving other problems)
Further, in the above invention, a storage unit that stores the following formula (1) is provided, and the control unit substitutes the depth of focus d input by the measurer with the input device into the formula (1). the aperture value F of the device may be Unishi due to set the.
d = ± (ε × F) (1)
Here, ε is an allowable circle of confusion .

Further, according to the invention, and it is possible to adjust the intensity I of the excitation light emitted from the light source, a storage unit for storing the initial intensity I _s of the exciting light emitted from the light source comprising Rutotomoni, wherein, based on the luminance value of the fluorescence intensity distribution image taken by irradiating the excitation light of the initial intensity I _s, sets the intensity I of the excitation light emitted from the light source Can

1 is a schematic configuration diagram showing an example of an oxygen concentration measuring apparatus according to an embodiment of the present invention. The flowchart for demonstrating the adjustment method of this invention. The schematic block diagram which shows an example of the conventional oxygen concentration measuring apparatus. Sectional drawing which shows an example of a polymer electrolyte fuel cell.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and it goes without saying that various aspects are included without departing from the spirit of the present invention.

FIG. 1 is a schematic configuration diagram showing an example of an oxygen concentration measuring apparatus according to an embodiment of the present invention. In addition, the same code | symbol is attached | subjected about the thing similar to the conventional oxygen concentration measuring apparatus 51 mentioned above.
The oxygen concentration measuring device 1 includes a light irradiation unit 10, an imaging unit 20, an arrangement unit 30 on which an inspection object S coated with a fluorescent paint is arranged, and a computer 40 that controls the entire oxygen concentration measuring device 1. Prepare. One direction horizontal to the ground is defined as an X direction, a direction horizontal to the ground and perpendicular to the X direction is defined as a Y direction, and a direction perpendicular to the X direction and the Y direction is defined as a Z direction.

The computer 40 includes a CPU (control unit) 41 and a memory (storage unit) 44, and a monitor (display device) 42 and an operation unit (input device) 43 are connected to each other. In addition, the functions processed by the CPU 41 will be described as a block. A light source control unit 41a that controls the laser light source 15, an imaging device control unit 41b that controls the high-speed photographing camera 21, a light source control unit 41a, and an imaging device control unit 41b. And a calculation unit 41c that outputs an instruction signal.
In addition, the memory 44 stores a relational expression storage area 44a that stores the relation (1) indicating the relation between the focal depth d and the aperture value F, and the initial intensity I _{s of the} excitation light emitted from the laser light source 15 (for example, emission An initial data storage area 44b for storing an intensity of 10% of the maximum possible intensity, and an optimum range luminance value (for example, a luminance value of 40% to 60% of the maximum imageable luminance value of the high-speed camera 21). And an optimum range luminance value storage area 44c.
d = ± (ε × F) (1)
Here, ε is an allowable circle of confusion .

When the depth of focus d and the measurement time interval t are input by the operation unit 43, the calculation unit 41c substitutes the depth of focus d input by the operation unit 43 into Expression (1), thereby and calculates and sets the aperture value F, an instruction signal to the initial intensity I _s of the intensity I of the excitation light with the measurement time interval t which is input by the operation unit 43 as the initial exposure time T _S of the high-speed imaging camera 21 First, control to output to the light source control unit 41a and the imaging device control unit 41b is performed. Thereafter, based on the luminance value of the photographed fluorescence intensity distribution image, an instruction signal for calculating and setting the exposure time T and the intensity I of the excitation light of the high-speed photographing camera 21 is set as the light source control unit 41a and the imaging device control unit. Next, the control to output to 41b is performed.

When the instruction signal from the calculation unit 41c is input, the imaging device control unit 41b controls the high-speed photographing camera 21 based on the instruction signal, and then performs control for acquiring a fluorescence intensity distribution image from the high-speed photographing camera 21. .
When the instruction signal from the calculation unit 41 c is input, the light source control unit 41 a controls the laser light source 15 based on the instruction signal and the intensity I detected by the power meter 11.

Here, an adjustment method for adjusting the aperture value F, the exposure time T, the intensity I of the excitation light, and the like of the high-speed photographing camera 21 with the oxygen concentration measuring apparatus 1 will be described. FIG. 2 is a flowchart for explaining the adjustment method.
First, in the process of step S <b> 101, the measurer places the inspection body S to which the fluorescent paint is applied on the placement unit 30.
Next, in the process of step S <b> 102, the measurer inputs the focal depth d and the measurement time interval t with the operation unit 43. That is, in the oxygen concentration measuring apparatus 1, a desired aperture value F, a desired exposure time T, and a desired intensity I of excitation light are not input.

Next, in the process of step S103, the calculation unit 41c calculates and sets the aperture value F of the high-speed shooting camera 21 by substituting the depth of focus d input by the operation unit 43 into Equation (1).
Next, in the process of step S <b> 104, the calculation unit 41 c sets the measurement time interval t input by the operation unit 43 to be the initial exposure time T _S of the high-speed photographing camera 21.
Next, in the process of step S105, calculation unit 41c sets the intensity I of the excitation light to the initial intensity _{I s.}

Next, in the process of step S <b> 106, the imaging device control unit 41 b acquires a fluorescence intensity distribution image from the high-speed shooting camera 21.
Next, in the process of step S107, the calculation unit 41c determines that the maximum luminance value in the photographed fluorescence intensity distribution image is an optimal range luminance value (for example, a luminance that is 40% to 60% of the maximum imageable luminance value of the high-speed imaging camera 21). Value). When the maximum luminance value in the photographed fluorescence intensity distribution image is within the optimum range (for example, a luminance value of 40% to 60%), this flowchart is terminated as the adjustment is completed.

  On the other hand, when the maximum luminance value in the photographed fluorescence intensity distribution image exceeds the maximum luminance value in the optimum range (for example, the luminance value that is 60% of the maximum imageable luminance value of the high-speed imaging camera 21), in the process of step S108 The calculation unit 41c sets the exposure time T to be shorter than the current exposure time T, and returns to the process of step S106. At this time, for example, the calculation unit 41c calculates the exposure time T using a binary search method or the like, or calculates it to be 10% shorter, for example.

Further, when the maximum luminance value in the photographed fluorescence intensity distribution image is lower than the minimum luminance value in the optimum range (for example, the luminance value of 40% of the maximum imageable luminance value of the high-speed imaging camera 21), in the process of step S109. The calculation unit 41c determines whether or not the intensity I of the excitation light is the maximum intensity that can be emitted. When it is determined that the intensity I of the excitation light is the maximum intensity that can be emitted, this flow chart is terminated with the adjustment impossible.
On the other hand, if it is determined that the intensity I of the excitation light is not the maximum intensity that can be emitted, the calculation unit 41c sets, for example, 10% stronger than the intensity I of the current excitation light in the process of step S110, The process returns to step S106.

  As described above, according to the oxygen concentration measuring apparatus 1, the aperture value F, the exposure time T, the intensity I of excitation light, and the like of the high-speed photographing camera 21 can be easily adjusted.

  The present invention measures the oxygen concentration distribution in the measurement target area by applying fluorescent paint to the measurement target area, generating fluorescence by irradiating the fluorescent paint surface with excitation light, and photographing the fluorescence intensity distribution. It can be used for an oxygen concentration measuring device.

DESCRIPTION OF SYMBOLS 1 Oxygen concentration measuring device 10 Light irradiation part 15 Laser light source 20 Imaging part 21 High-speed imaging camera (imaging apparatus)
40 control unit 43 input device

Claims (2)

A light irradiation unit having a light source for irradiating excitation light to a measurement target region to which a fluorescent paint having oxygen quenching property is applied;
An imaging unit having an imaging device for photographing the fluorescence intensity distribution of the fluorescent paint surface applied to the measurement target region;
A controller that measures the oxygen concentration distribution in the measurement target region based on the fluorescence intensity distribution;
It is possible to adjust the aperture value (F) of the imaging device and the exposure time (T) of the imaging device, and to adjust the intensity (I) of excitation light emitted from the light source. A concentration measuring device,
A storage unit for storing the initial intensity (I _s ) of excitation light emitted from the light source ;
It further has an input device on which an input operation is performed,
The control unit receives the depth of focus (d) and the aperture value (F) by inputting the depth of focus (d), which is ensured by the measurer to acquire the fluorescence intensity distribution image of the fluorescent paint surface with the input device. ) And the aperture value (F) of the imaging device is set using a relational expression with
The measurement time interval (t) input by the measurer with the input device is the initial exposure time (T _S ) of the imaging device ,
When the luminance value of the captured fluorescence intensity distribution image is high, the exposure time (T) of the imaging device is changed, whereas when the luminance value of the fluorescence intensity distribution image is low, the intensity of the excitation light ( An oxygen concentration measuring apparatus characterized by changing I) . A storage unit for storing the following formula (1) is provided,
Wherein the control unit, wherein, wherein the benzalkonium set aperture value (F) of the imaging device by substituting the input depth of focus (d) by the measurer by the input device to the formula (1) Item 2. The oxygen concentration measuring device according to Item 1.
d = ± (ε × F) (1)
Here, ε is an allowable circle of confusion .

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