JP3466360B2 - Moisture content detection device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water content detection device for detecting the water content of an object to be detected.

[0002]

2. Description of the Related Art Since the physical and scientific properties of an object change depending on the amount of water contained in the object, it is necessary to detect the water content of the object in quality control of products and various process controls. Many. The method of detecting the water content of an object is to irradiate the object with infrared light in the wavelength range that water absorbs and infrared light in the wavelength range with little change in water absorption, and There is a method of detecting the moisture content of a detected object from the intensity of each reflected infrared light, and a moisture content detection device that implements this method is also known.

In this moisture-containing detector, infrared light having two wavelengths, that is, infrared light in a wavelength range absorbed by water and infrared light in a comparative wavelength range in which water absorption is small, are emitted from a light source. It suffices to irradiate the object to be detected, receive the reflected light at the light receiving section consisting of a light receiving element, and judge the water content of the object to be detected from the output signal of the light receiving section. In order to correct the above, infrared light with two or more wavelengths, for example, light in the absorption wavelength range of water, light on the shorter wavelength side than the absorption wavelength range of water, and light on the longer wavelength side than the absorption wavelength range of water are corrected from the light source. There is a method of irradiating and receiving the reflected light separately by the light receiving unit and determining the water content of the detected object from the output signal of the light receiving unit.

Further, in Japanese Patent Application Laid-Open No. 55-29726, a turret type sector having a plurality of filters is rotated so that light from a common light source is sequentially separated into light of each wavelength by the plurality of filters. , A method of measuring water content by infrared rays in which light of each of these separated wavelengths is received by a light receiving section and the water content of an object to be detected is judged from an output signal of the light receiving section. In this moisture measuring method, when light in the intermediate wavelength range is required, a filter for separating the light in the intermediate wavelength range is added in the turret type sector.

Further, in a moisture-containing detecting device having a plurality of light emitting parts having different emission wavelengths for sequentially irradiating the object to be detected with light and a light receiving part for receiving reflected light from the object to be detected,
Control for fetching a plurality of light receiving signals from the light receiving unit based on the sequential light emitting operation of the plurality of light emitting units and judging the moisture content of the detected object based on a preset value from the comparison of the plurality of light receiving signals. There has been proposed a moisture content detection device characterized by including a portion.

[0006]

In the above-described moisture-containing detector, the light receiving section must be selected so as to have uniform light receiving sensitivity for all comparison wavelengths before and after the absorption wavelength range of water. It was difficult to accurately determine the water content of the detected object due to the factors. Further, in the above-mentioned infrared moisture measuring method, since it is carried out by a device having a turret type sector having a plurality of filters and a movable part, the whole device tends to be large, and it is difficult to speed up moisture measurement.

In the moisture-containing detection device in which the plurality of light emitting units sequentially emit light, when light having a different wavelength from the light emitted from the plurality of light emitting units to the object to be detected is required, the light emitting unit is provided each time. Had to expand.

Further, in the above-mentioned water content detecting device, in order to correct the influence of factors other than the water content of the object to be detected, infrared light of two or more wavelengths, for example, light in the water absorption wavelength range and water absorption Light with a wavelength shorter than the wavelength range and light with a wavelength longer than the absorption wavelength range of water are radiated, and the reflected light is received separately by the light receiving section, and the moisture content of the detected object is detected from the output signal of the light receiving section. When making a decision, it is desirable to select two light emitting parts that radiate light on both sides of the water absorption wavelength range so as to have an emission distribution with the same wavelength difference. Is different for each component, and it is difficult to select by combining two light-emitting units that have the same emission difference as the emission distribution of the emission unit that irradiates light in the absorption wavelength range of water. It was

According to the present invention, the moisture content of a detected object can be quickly and accurately determined without being affected by factors other than the moisture content of the detected object, thereby enabling downsizing and cost reduction. An object is to provide a detection device.

[0010]

In order to achieve the above object, the invention according to claim 1 is to provide a plurality of light emitting portions having different emission wavelengths for sequentially irradiating the object to be detected with light and reflection from the object to be detected. A plurality of light emitting units, which are arranged at a predetermined angle with respect to the object to be detected and perform a lighting operation of sequentially irradiating the object with light, A moisture-containing detection device comprising: a first light emitting portion having a light emission distribution in an absorption wavelength region, and a second light emitting portion having a light emission distribution in a shorter wavelength side or a longer wavelength side than an absorption wavelength region of water. Output signal of the light receiving unit during the lighting operation of the light emitting unit, output signal of the light receiving unit during the lighting operation of the first light emitting unit and the second light emitting unit, and lighting of the second light emitting unit Perform predetermined calculation based on the output signal of the light receiving part during operation It is equipped with a control unit that determines the moisture content of the object to be detected based on the calculation result and a preset value, and a large number of light receiving signals can be obtained from the light receiving unit with a small number of light emitting units. The moisture content of the object to be detected can be quickly and accurately determined without being affected by factors other than the moisture content of the object to be detected, and downsizing and cost reduction can be achieved.

According to a second aspect of the present invention, a plurality of light emitting portions having different emission wavelengths for sequentially irradiating the detected object with light and a light receiving portion for receiving the reflected light from the detected object are provided. The first light emitting unit is disposed at a predetermined angle with respect to the light receiving unit with respect to the detected object, performs a lighting operation of sequentially irradiating the detected object with light, and has a light emission distribution in the absorption wavelength range of water. And a second emission distribution with a shorter wavelength side than the absorption wavelength range of water
And a third light emitting part having a light emission distribution on a wavelength side longer than the absorption wavelength range of water,
An output signal of the light receiving unit during the lighting operation of the first light emitting unit, an output signal of the light receiving unit during the lighting operation of the first light emitting unit and the second light emitting unit, and the second light emission An output signal of the light receiving section during the lighting operation of the section,
A predetermined signal is output based on the output signal of the light receiving unit during the lighting operation of the second light emitting unit and the third light emitting unit and the output signal of the light receiving unit during the lighting operation of the third light emitting unit. It is equipped with a control unit that performs a calculation and determines the moisture content of the object to be detected based on the calculation result and a preset value. It is possible to obtain many light reception signals from the light reception unit with a small number of light emission units. As a result, the moisture content of the detected object can be quickly and accurately determined without being affected by factors other than the moisture content of the detected object, and downsizing and cost reduction can be achieved.

According to a third aspect of the present invention, in the moisture content detecting apparatus according to the second aspect, the first light emitting portion has a light emission distribution having a spectral sensitivity peak at 1.45 μm in a water absorption wavelength range. The second light emitting portion has a light emitting portion having a light emission distribution having a peak of spectral sensitivity at 1.3 μm on the shorter wavelength side than the absorption wavelength range of water, and the third light emitting portion absorbs water. It is composed of a light emitting portion having a light emission distribution having a peak of spectral sensitivity at 1.55 μm on the longer wavelength side than the wavelength range, and a large number of light receiving signals can be obtained from the light receiving portion with a small number of light emitting portions, and the detected object can be detected. The moisture content of the object to be detected can be quickly and accurately determined without being affected by factors other than the moisture content, and downsizing and cost reduction can be achieved.

The invention according to claim 4 is the invention according to claim 2 or 3.
In the moisture content detection device according to the description, the light irradiation angle of the plurality of light emitting units is such that the optical axis angle becomes larger as the light on the longer wavelength side, and the light having different emission wavelengths from the plurality of light emitting units is the same light. Even if the longer-wavelength side light penetrates into the object to be detected when the object to be detected is irradiated at the axial angle, the influence can be minimized even if there is a difference in the amount of reflected light.

[0014]

1 shows an embodiment of the invention according to claims 2-4. Moisture-containing detector 1 of this embodiment
Is a detection unit 7 including a plurality of light emitting units 2 to 4 each configured of a light emitting diode that emits near infrared light, a light receiving unit 5, and an amplifier circuit 6 that amplifies a light receiving signal from the light receiving unit 5. , Light emission drive unit 8, control unit 9, input unit 10, output unit 1
1 and the display unit 12 are provided to detect the moisture content (moisture content) of the detection object 13 at the detection position. The control unit 9 includes a CPU 14,
The ROM 15, the RAM 16, and the I / O 17 are used. By housing the plurality of light emitting units in one case, the size and cost of the detection unit 7 can be reduced.

As shown in FIG. 2, the light emitting diodes 2 to 4 have different emission wavelengths from each other, and the light emitting diode 2 has a light emission distribution on a shorter wavelength side than a wavelength range where water is absorbed (water absorption wavelength range). It has a spectral sensitivity peak at 0.3 μm.
The light emitting diode 3 has an emission distribution in the wavelength range absorbed by water and has a spectral sensitivity peak at 1.45 μm, and the light emitting diode 4 has an emission distribution in the longer wavelength side than the wavelength range absorbed by water. It has a peak of spectral sensitivity at 1.55 μm. The light receiving portion 5 is composed of an InGaAs light receiving element and has a light receiving sensitivity of 0.7 μm to 1.7 μm.

The light receiving portion 5 is arranged so as to receive the reflected light of different optical axis angles from the light emitting diodes 2 to 4 on the normal line of the detection surface of the object to be detected 13. The light emitting diodes 3 are arranged so that the optical axis angle with respect to the normal line of the detection surface of the detected object 13 is about 30 degrees, and the light emitting diodes 2 and 4 have the optical axis angle with respect to the normal line of the detection surface of the detected object 13. One container 7 at 25-35 degrees
It is placed in a. The light emitting diodes 2 and 4 have the same optical axis angle in a predetermined one direction with respect to the normal line of the detection surface of the object to be detected 13 as shown in FIG. 1, and as shown in FIG. The optical axis angles θ ₁ and θ _{2 in} a direction perpendicular to the normal to the detection surface of the object 13 are different.

The light emitting diodes 2 to 4 are sequentially driven by the light emission drive section 8 to irradiate the detected object 13 at the detection position with light, and the light receiving section 5 receives the reflected light from the detected object 13 at the detection position. . The output signal of the light receiving unit 5 is amplified by the amplifier circuit 6 and input to the A / D conversion unit of the control unit 9 to be converted into A / D.
D converted. 4 to 6 show the operation flow of this embodiment, and FIG. 7 shows the operation timing of this embodiment. In FIG. 7, LED indicates a light emitting diode and PD indicates a light receiving portion.

In the present embodiment, when the power is turned on as shown in FIG. 4, the control section 9 carries out an initial setting diagnostic process in accordance with a program stored in the ROM 15, and the result is output to the output section 10. The detected object 13 is displayed as being detectable or abnormal. According to the moisture content detection program, the control unit 9 takes in the output signal of the light receiving unit 5 via the amplifier circuit 6 based on the moisture content detection start signal from the input unit 10 without operating the light emitting units 2 to 4. A / D conversion is carried out and is used as a detection signal PD0.

Subsequently, the control unit 9 gives a light emission signal to the light emission drive unit 8 to sequentially cause the light emission units 2 to 4 to emit light, and outputs the output signal of the light reception unit 5 to the amplification circuit 6 in synchronization with the light emission signal. Take in intermittently through. That is, the control unit 9 first turns on the light emitting unit 2 and outputs the output signal of the light receiving unit 5 with respect to the light emitted from the light emitting unit 2 and received by the light receiving unit 5, to the amplifier circuit 6.
Captured via A, converted into A / D, and detected as PD
The detection signal PD0 which has been immediately fetched and A / D converted is set to 1 and PD1 = PD1−PD0 is set.

Next, the control section 9 turns on the light emitting section 3,
The output signal of the light receiving unit 5 with respect to the light emitted from the light emitting units 2 and 3 and received by the light receiving unit 5 is taken in through the amplifier circuit 6 and A / D converted, and is immediately taken in first as the detection signal PD2. The A / D-converted detection signal PD0 is subtracted to set PD2 = PD2-PD0. Next, the control unit 9
The light emitting unit 2 is turned off, and the light receiving unit 5 is irradiated by the light emitting unit 3.
The output signal of the light-receiving unit 5 for the light received by is taken in through the amplifier circuit 6 and A / D converted, and this is detected signal P.
Immediately as D3, the detection signal PD0 which has been previously fetched and A / D converted is subtracted to set PD3 = PD3-PD0.

Next, the control section 9 turns on the light emitting section 4,
The output signal of the light receiving portion 5 for the light emitted from the light emitting portions 3 and 4 and received by the light receiving portion 5 is taken in through the amplifier circuit 6 and A / D converted, and is immediately taken in first as the detection signal PD4. The A / D-converted detection signal PD0 is subtracted to set PD4 = PD4-PD0. Next, the control unit 9
The light emitting section 3 is turned off, and the light receiving section 5 is illuminated by the light emitting section 4.
The output signal of the light-receiving unit 5 for the light received by is taken in through the amplifier circuit 6 and A / D converted, and this is detected signal P.
Immediately as D5, the detection signal PD0 which has been previously fetched and A / D converted is subtracted to set PD5 = PD5-PD0.

Next, the control section 9 turns off the light emitting section 4,
After that, the same operation is repeated to generate an n-th time signal indicating how many times the light emitting units 2 to 4 are sequentially turned on.
The control unit 9 controls the light-emitting units 2 to 4 to sequentially turn on n times,
When the turn signal becomes n, the detection signals from PD1 to PD5 are stored in the RAM 16. Six detection signals PD0 to PD5 are obtained as data every time the moisture content detection process of the object to be detected 13 is repeated n times of the moisture content detection process. That is, 6n
Data are obtained. The control unit 9 stores the 6n pieces of data in the RAM 16 when the moisture content detection process is repeated n times.

The moisture content of the object to be detected 13 is detected n times and averaged to improve the detection accuracy. The control unit 9
PD1 to P5 by averaging the detection signals PD1 to PD5
D5 average values ΣPD1 / n, ΣPD2 / n, ΣPD3
/ N, ΣPD4 / n, ΣPD5 / n are obtained, and the average value of them is set as PD1n to PD5n [{(PD1n + PD5n) / 2} / PD3n] × (P
D2n / PD4n) is used to execute the operation, and the ROM is calculated from the operation result.
Moisture content% of the detected object 13 preset in 15
And the moisture content% of the object to be detected 13 are determined and determined based on table data showing the relationship between the calculation result of the above calculation formula.

In this case, the control section 9 controls the PDs 1n to P above.
D5n is the detection result for the moisture content of the detected object 13 (the detection result that can be determined by determining the moisture content% of the detected object 13 based on the table data).
It is determined whether or not PD1n to PD5n are the detected objects 1
If the detection result is not for the water content of 3, the display unit 1
Display the abnormality on 2.

Further, the controller 9 controls the PD1n to PD5.
When n is the detection result for the moisture content of the detected object 13, the moisture content% of the detected object 13 is determined and determined from the above PD1n to PD5n based on the table data (PD1n to PD5n and the above). The moisture content% of the object to be detected 13 is judged and determined by comparison with the table data).

The control unit 9 judges whether or not the determined moisture content% of the detected object 13 is within a predetermined range to determine whether or not the moisture content% of the detected object 13 is normal. If the moisture content% of the object to be detected 13 is not within the predetermined range, an abnormality is displayed on the display unit 12. PD1n to P
When D5n is not the detection result for the moisture content of the detected object 13 or when the moisture content% of the detected object 13 is not within the predetermined range, the distance between the detected object 13 and the light emitting units 2 to 4 is appropriate. If the reflected light from the object to be detected 13 cannot be received by the light receiving section 5 or the output signal of the light receiving section 5 is saturated due to strong ambient light, the water content of the object to be detected 13 is repeatedly detected n times. It is possible that the distance between the object to be detected 13 and the light emitting units 2 to 4 changes and the output signal of the light receiving unit 5 changes significantly.

In the detection of the moisture content of the object to be detected 13, the control section 9 controls the amplifier circuit 6 to output the output signal of the light receiving section 5 when the light emitting sections 2 to 4 do not irradiate the object to be detected 13 with light. It is detected as a detection signal PD0 via
Output signals of the light receiving section 5 in each state in which one or two of the four light emitting sections irradiate the detected object 13 with light are detected as detection signals PD1 to PD5 via the amplifier circuit 6 and detected. Since the detection signal PD0 is subtracted from PD1 to PD5, the influence of ambient light, the influence of temperature, and the like can be eliminated.

Further, the controller 9 controls the ROM 1 as described above.
5, the moisture content% of the object to be detected 13 is determined based on the table data set in advance, and it is determined by an experiment, and the PD1n to PD5n and the object to be detected 13 shown in FIG. Input unit 10 is used to determine whether or not there is an external setting of a mathematical expression and coefficient set by regression analysis based on the relationship with the moisture content%.
Judgment based on the input signal from.

Then, the control unit 9 inputs the P value obtained from the experiment, which is input from the input unit 10 when there is an external setting.
D1n to PD5n and the moisture content% of the object to be detected 13 are taken in by the data of the formula and the coefficient set by the regression analysis, and if the data is abnormal, the abnormality is displayed on the display unit 12, and the data is abnormal. If not, the PD1n to PD5n are calculated based on the data of the mathematical expression and the coefficient, and the moisture content% of the detected object 13 is obtained.

Further, the control section 9 causes the display section 12 to display the moisture content% of the detected object 13 determined in accordance with an instruction input from the outside through the input section 10, or the output section 1.
1 to output to the outside. The control unit 9 repeats the above operation each time a moisture content detection start signal is input from the input unit 10 until the power is turned off.

Here, the moisture content% of the detected object 13 is 4%.
In the following low moisture content state, the change amount of the detection signals PD1n to PD5n becomes a small value in proportion to the moisture content of the detected object 13. There is a time lag in the timing of detecting the water content of the detected object 13, and the detection signals PD1n to PD5n are set to n.
Although an attempt has been made to reduce the error by retrieving and averaging, the detection signal P is obtained by using light of different wavelengths.
Since D1n to PD5n are detected, the influence of noise and the influence of the surface of the detected object 13 can be minimized. Further, the light emitting parts 2 and 4 are housed in one container 7a,
The light emitting units 2 and 4 may be separately arranged.

As described above, this embodiment is an embodiment of the invention according to claim 2, and includes a plurality of light emitting portions 2 to 4 having different emission wavelengths for sequentially irradiating the detection object 13 with light.
A plurality of light emitting units 2 to 4 are arranged at a predetermined angle with respect to the object 13 to be detected, and the object to be detected 13 is provided. The first light emitting section 3 having a light emission distribution in the water absorption wavelength range and the second light emitting section 2 having a light emission distribution in the shorter wavelength side than the water absorption wavelength range And a third light emitting section 4 having a light emission distribution on the longer wavelength side than the absorption wavelength range of water, wherein the first light emitting section 3 is provided.
Output signal of the light receiving section 5 during the lighting operation, the output signal of the light receiving section 5 during the lighting operation of the first light emitting section 3 and the second light emitting section 2, and the second light emitting section 2
Output signal of the light receiving section 5 during the lighting operation of the second light emitting section 3, the output signal of the light receiving section 5 during the lighting operation of the second light emitting section 3 and the third light emitting section 4, and the third light emitting section 4.
A predetermined calculation is performed on the basis of the output signal of the light receiving unit 5 during the lighting operation of, and the calculation result and a preset value (table data, a mathematical expression set by regression analysis,
Since the control unit 9 for determining the moisture content of the detected object 13 based on the coefficient data) is provided, a large number of light reception signals can be obtained from the light receiving section with a small number of light emitting sections, and other than the moisture content of the detected object. The moisture content of the object to be detected can be quickly and accurately determined without being affected by the above factor, and downsizing and cost reduction can be achieved.

In addition, this embodiment is an embodiment of the invention according to claim 3, wherein in the moisture content detecting device according to claim 2, the first light emitting portion 3 has a water absorption wavelength range of 1 The second light emitting unit 2 has an emission distribution having a spectral sensitivity peak at 1.3 μm, which is shorter than the absorption wavelength range of water. The third light emitting unit 4 includes a light emitting unit.
Is composed of a light emitting part having a light emission distribution having a peak of spectral sensitivity at 1.55 μm on the longer wavelength side than the absorption wavelength range of water, so a large number of light receiving signals can be obtained from the light receiving part with a small number of light emitting parts. The moisture content of the object to be detected can be quickly and accurately determined without being affected by factors other than the moisture content of the object, and downsizing and cost reduction can be achieved.

Further, this embodiment is an embodiment of the invention according to claim 4, and in the moisture content detecting device according to claim 2 or 3, the light irradiation angle θ of the plurality of light emitting portions 2 and 4 is. ₁ and θ ₂ are set so that the longer the light on the longer wavelength side, the larger the optical axis angle (θ ₁ > θ ₂ ), so that light with different emission wavelengths from multiple light emitting parts has the same optical axis angle. Even if the longer wavelength light penetrates into the object to be detected and the difference in the reflected light amount occurs, the influence can be minimized.

In the above embodiment, the light emitting units 2 to
The moisture content of the detected object was detected with the light of 3 wavelengths from 4,
In one embodiment of the invention according to claim 1, in the above embodiment, the light emitting unit 2 or the light emitting unit 4 is omitted, and the water content of the detected object is detected with light of two wavelengths. Furthermore, the control unit 9
Are the detection signals PD1n to PD3n as in the above embodiment.
Alternatively, PD3n to PD5n are obtained, and these detection signals P
From D1n to PD3n or PD3n to PD5n, a calculation is executed by the calculation formula PD1n / PD3n or PD5n / PD3n, and from this calculation result, the ROM is read.
Moisture content% of the detected object 13 preset in 15
And the moisture content% of the object to be detected 13 are determined and determined based on table data showing the relationship between the calculation result of the above calculation formula.

Further, the control unit 9 inputs the above-mentioned PD obtained by experiments, which is input from the input unit 10 when there is an external setting.
1n to PD3n or PD3n to PD5n and the moisture content% of the object to be detected 13 are taken in from the above PD1n to PD3n or PD3n to PD5n based on the data of the equations and coefficients set by regression analysis. The moisture content% of the detected object 13 is obtained.

As described above, in one embodiment of the invention according to claim 1, a plurality of light emitting portions having different emission wavelengths for sequentially irradiating the object to be detected 13 with light and the light reflected by the object to be detected 13 are received. The plurality of light emitting units are arranged at a predetermined angle with respect to the light receiving unit 5 with respect to the object to be detected 13 and perform a lighting operation of sequentially irradiating the object to be detected 13 with light. First light emitting portion 3 having an emission distribution in the absorption wavelength region of
And a second light emitting part 2 or 4 having a light emission distribution on the short wavelength side or the long wavelength side of the absorption wavelength range of water, wherein the first light emitting part 3 is operated during lighting operation. Output signal of the light receiving unit 5, output signal of the light receiving unit 5 at the time of lighting operation of the first light emitting unit 3 and the second light emitting unit 2 or 4, and lighting of the second light emitting unit 2 or 4. A control unit 9 is provided for performing a predetermined calculation based on the output signal of the light receiving unit 5 during operation and determining the water content of the object to be detected 13 based on the calculation result and a preset value. Therefore, many light receiving signals can be obtained from the light receiving unit with a small number of light emitting units, and the moisture content of the detected object can be quickly and accurately determined without being affected by factors other than the moisture content of the detected object, It is possible to reduce the size and cost.

[0038]

As described above, according to the first aspect of the present invention, a plurality of light emitting portions having different emission wavelengths for sequentially irradiating the object to be detected with light and a light receiving device for receiving the reflected light from the object to be detected. The plurality of light emitting units are arranged at a predetermined angle with the light receiving unit with respect to the object to be detected, perform a lighting operation of sequentially irradiating the object to be detected, and emit light in a water absorption wavelength range. In a moisture-containing detection device having a first light emitting portion having a distribution and a second light emitting portion having a light emission distribution on a short wavelength side or a long wavelength side of an absorption wavelength range of water, lighting of the first light emitting portion An output signal of the light receiving portion during operation, an output signal of the light receiving portion during lighting operation of the first light emitting portion and the second light emitting portion, and the light reception during light emitting operation of the third light emitting portion Perform a predetermined calculation based on the output signal of the section,
Since the control unit that determines the moisture content of the detected object based on the calculation result and the preset value is provided, many light receiving signals can be obtained from the light receiving section with a small number of light emitting sections, and The moisture content of the object to be detected can be quickly and accurately determined without being affected by factors other than the moisture content, and downsizing and cost reduction can be achieved.

According to the invention of claim 2, a plurality of light emitting portions having different light emission wavelengths for sequentially irradiating the object to be detected with light,
A light-receiving unit for receiving reflected light from the object to be detected, wherein the plurality of light-emitting units are arranged at a predetermined angle with the light-receiving unit with respect to the object to be detected and sequentially illuminate the object to be detected. A first light emitting part that operates and has a light emission distribution in the water absorption wavelength range, a second light emitting part that has a light emission distribution in the shorter wavelength side than the water absorption wavelength range, and a longer wavelength than the water absorption wavelength range In a moisture content detection device having a third light emitting portion having a light emission distribution on the side, an output signal of the light receiving portion during the lighting operation of the first light emitting portion, the first light emitting portion and the second light emitting portion. Output signal of the light receiving section during lighting operation of the light emitting section, output signal of the light receiving section during lighting operation of the second light emitting section, and lighting operation of the second light emitting section and the third light emitting section The output signal of the light receiving section at the time and the lighting operation of the third light emitting section Since a predetermined calculation is performed on the basis of the output signal of the light receiving section, and a control section for judging the moisture content of the detected object based on the calculation result and a preset value is provided, a small number of light emitting sections are provided. Since many light receiving signals can be obtained from the light receiving part, the moisture content of the detected object can be quickly and accurately determined without being affected by factors other than the moisture content of the detected object, and the size and cost can be reduced. Can be realized.

According to the third aspect of the present invention, in the moisture content detector according to the second aspect, the first light emitting portion has an emission distribution having a spectral sensitivity peak at 1.45 μm in the water absorption wavelength range. The second light emitting portion has a light emitting portion having a light emission distribution having a peak of spectral sensitivity at 1.3 μm on the shorter wavelength side than the absorption wavelength range of water.
The light emitting part of is 1.55 μm on the longer wavelength side than the absorption wavelength range of water
Since it consists of a light emitting part having a light emission distribution having a peak of spectral sensitivity, it is possible to obtain a large number of light receiving signals from the light receiving part with a small number of light emitting parts, and to be detected without being affected by factors other than moisture content of the detected object. It is possible to quickly and accurately determine the water content of an object, which enables downsizing and cost reduction.

According to the fourth aspect of the present invention, in the moisture content detecting apparatus according to the second or third aspect, the light irradiation angles of the plurality of light emitting portions are set such that the light on the longer wavelength side has a larger optical axis angle. Therefore, when light with different emission wavelengths is emitted from a plurality of light emitting parts to the detected object at the same optical axis angle, the longer wavelength light penetrates into the detected object and the amount of reflected light varies. Can minimize the effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the invention according to claims 2-4.

FIG. 2 is a characteristic diagram showing spectral sensitivities of a light emitting unit and a light receiving unit in the same embodiment.

FIG. 3 is a cross-sectional view showing a part of the same embodiment.

FIG. 4 is a flowchart showing an operation flow of the same embodiment.

FIG. 5 is a flowchart showing in detail a part of the same operation flow.

FIG. 6 is a flowchart showing in detail another part of the above operation flow.

FIG. 7 is a timing chart showing the operation timing of the same embodiment.

FIG. 8 is a characteristic diagram showing the relationship between the detection signal obtained in the experiment of the same embodiment and the water content of the detected object.

[Explanation of symbols]

1 Moisture content detector 2-4 Light emitting part 5 Light receiving part 6 amplification circuit 7 Detector 8 Light emission drive 9 control unit 10 Input section 11 Output section 12 Display 13 Detected object

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields investigated (Int.Cl. ⁷ , DB name) G01N 21/00-21/61 Practical file (PATOLIS) Patent file (PATOLIS)

Claims (4)

(57) [Claims] 1. A plurality of light emitting portions having different emission wavelengths for sequentially irradiating the detected object with light, and a light receiving portion for receiving reflected light from the detected object, wherein the plurality of light emitting parts are The first light-emitting portion, which is arranged at a predetermined angle with respect to the object to be detected, performs a lighting operation of sequentially irradiating the object to be detected with light, and has an emission distribution in the absorption wavelength range of water, and an absorption wavelength of water. In a moisture-containing detection device having a second light emitting portion having a light emission distribution on a short wavelength side or a long wavelength side of a region, an output signal of the light receiving portion at the time of lighting operation of the first light emitting portion and the first light emitting portion, Predetermined calculation is performed based on the output signal of the light receiving unit during the lighting operation of the second light emitting unit and the light emitting unit and the output signal of the light receiving unit during the lighting operation of the second light emitting unit. , The moisture content of the detected object can be determined based on this calculation result and the preset value. Moisture content detecting apparatus characterized by comprising a control unit for. 2. A plurality of light emitting portions having different emission wavelengths for sequentially irradiating the detected object with light and a light receiving portion for receiving reflected light from the detected object, wherein the plurality of light emitting parts are provided. The first light-emitting portion, which is arranged at a predetermined angle with respect to the object to be detected, performs a lighting operation of sequentially irradiating the object to be detected with light, and has an emission distribution in the absorption wavelength range of water, and an absorption wavelength of water. In the moisture-containing detection device having a second light emitting portion having a light emission distribution on the shorter wavelength side than the wavelength range and a third light emitting portion having a light emission distribution on the longer wavelength side than the water absorption wavelength range, the first light emission Output signal of the light receiving section during the lighting operation of the light emitting section, output signals of the light receiving section during the lighting operation of the first light emitting section and the second light emitting section, and during the lighting operation of the second light emitting section The output signal of the light receiving unit and the points of the second light emitting unit and the third light emitting unit A predetermined calculation is performed based on the output signal of the light receiving section during operation and the output signal of the light receiving section during the lighting operation of the third light emitting section, and the calculation result and a preset value are also calculated. A water content detection device, further comprising a control unit for determining the water content of the object to be detected. 3. The water content detection device according to claim 2,
The first light emitting portion is composed of a light emitting portion having a light emission distribution having a peak of spectral sensitivity at 1.45 μm in the water absorption wavelength range, and the second light emitting portion is 1 on the shorter wavelength side than the water absorption wavelength range. A light emitting portion having a light emission distribution having a spectral sensitivity peak at 3 .mu.m, and the third light emitting portion having a light emission distribution having a spectral sensitivity peak at 1.55 .mu.m, which is a wavelength longer than the absorption wavelength range of water. A moisture content detecting device comprising: 4. The moisture content detecting device according to claim 2 or 3, wherein the light irradiation angles of the plurality of light emitting parts are such that the light on the longer wavelength side has a larger optical axis angle. Detection device.