JPH07198597A - Photoelectric measuring instrument - Google Patents

Abstract

PURPOSE:To provide a compact photoelectric measuring instrument which enables the obtaining of correct measuring information as for a subject moving or changing in condition at a high speed without causing measuring errors owing to changes in ambient temperature nor generating errors in measured values with respect to changes in the distance to the subject and those in angle thereto. CONSTITUTION:Light which is projected onto a subject and incident from the subject is branched off into two optical systems separately corresponding to photoelectrical transducers 15a and 15b by an optical path branching optical system 31 arranged in a box body 16 of photoelectrical transducers fixed. These photoelectrical transducers 15a and 15b are fixed on the same plane close to each other coupled thermally on a fixing member 16b of the photoelectrical transducer fixing part 16. The light branched off with the optical branching optical system 31 has an equal optical path length and admitted separately into the photoelectrical transducers 15a and 15b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric measuring device for separating light incident from an object to be measured and detecting information contained in the object to be measured. Electricity is obtained by dispersing light with light having a specific wavelength.
Converted into electric signals with a light conversion element, and from these converted electric signals, measure the film thickness, water content, component concentration, temperature, etc. of the coating material applied to high-speed moving plastic film, paper sheet, steel plate, etc. To a photoelectric measuring device.

[0002]

2. Description of the Related Art Generally, light is projected onto an object to be measured and the intensity of transmitted light or reflected light on the object to be measured is measured.
The degree of absorption of light of the characteristic absorption wavelength is detected to perform qualitative and quantitative measurements such as the thickness, component concentration, or water content of the measurement object, and the intensity of radiated light from the measurement object itself is measured. It is well known to measure the temperature of an object to be measured.

Conventionally, in this type of measurement in a production line or the like, a discontinuous spectroscopic element such as an interference filter is used for the purpose of spectral separation of the characteristic absorption wavelength. In addition, the light from the measurement object is divided into a wavelength (measurement wavelength) that has a correlation with the characteristics to be measured and a wavelength (reference wavelength) that is slightly different from it, in a time-division manner, and then condensed on the sensor surface. Or, by irradiating the measurement object with light that has been split into each wavelength in advance, collecting the returned light on the sensor surface and making it incident, and comparing and calculating the measured wavelength intensity and the reference wavelength intensity, the fluctuation of the light source An optoelectronic measuring device has been put into practical use, which performs measurement using a plurality of wavelengths so as to eliminate errors, fluctuations in sensitivity of the sensor element itself, changes in optical system, and errors due to stray light due to surface reflection of a measurement target.

An example of the photoelectric measuring device is shown in FIG.
And that shown in FIG. 10 have been proposed (see, for example, Japanese Patent Laid-Open No. 49-10782). The photoelectric measurement device of FIG. 9 passes through the measurement object 1 or the measurement object 1
In the optical path of the light receiving side of the reflection to the light reaching the photodetector 2 from arrow A ₁ holds a plurality of interference filters 3, 3, ... a
The rotating disk 4 which rotates as shown in FIG. 2 is arranged, and a slit (not shown) or the like provided in the rotating disk 4 is detected so that the light from the measuring object 1 causes the interference filters 3 and 3 to be detected. A timing detector 5 for detecting the timing of passing through. Then, the rotating disk 4 is rotated to detect the intensity of light passing through each interference filter 3 from one of the photodetectors 2 in time series and output from the timing detector 5 to the interference filter 3. , 3, ... From the recognition signals of the switching positions, the intensity signals of light of specific wavelengths corresponding to the individual interference filters 3 are separated, and the intensity signals of these separated lights are arithmetically processed to detect the absorbance. The measurement target 1 based on this absorbance
Qualitatively and quantitatively such as the thickness, component concentration, and water content of the product.

Further, the one shown in FIG.
The optical paths on the light-receiving side from the photodetectors 2a and 2b to the photodetectors 2a and 2b are formed by a plurality of optical paths 7a,
The interference filters 8 and 9 are arranged in the middle of the branched optical paths 7a and 7b. The intensity of light transmitted through each interference filter 8 and 9 is determined by the individual photodetectors 2a and 2a.
Each of the intensity signals of these lights detected in step b is subjected to arithmetic processing to detect the absorbance, and in the same manner as described above, the qualitative information such as the thickness, the component concentration, or the water content of the measurement target 1 can be obtained. Quantify.

[0006]

By the way, in the photodetector of FIG. 9, the light of the characteristic absorption wavelength and the light of the reference wavelength are sampled by the rotation of the rotary disk 4 and measured by the so-called time division method. Therefore, correct measurement is possible when the measurement object 1 is stationary or when the characteristics of the measurement object 1 do not change with time. However, when the measurement target 1 moves at a high speed, the timings at which the light of the characteristic absorption wavelength and the light of the reference wavelength are measured are different, so that when the measurement target 1 moves, the measurement positions of the respective wavelengths differ.

At this time, in the case where the object 1 to be measured is a light having a characteristic absorption wavelength and a light having a reference wavelength with little spatial change in transmittance or absorbance, a value close to a correct measured value is set. Although it can be obtained, it is difficult to obtain correct measurement data as described below when the local change of the transmittance or the absorbance is large or when the moving speed of the measuring object 1 is high. become.

Now, in FIG. 9, the output including the light sensitivity of the photodetector 1 is A _p for the light having the characteristic absorption wavelength at the position P of the measuring object 1, and is the light having the reference wavelength. On the other hand, it is assumed that B _p . The output of the photodetector 2 is A _q for the light of the characteristic absorption wavelength at the position Q of the measurement object 1 and B _q for the intensity of the light of the reference wavelength.
Suppose Since it takes time to switch the interference filters 3, 3, ..., The intensity of the light having the characteristic absorption wavelength is measured at the position P of the measurement target 1, and the intensity of the light having the reference wavelength is measured at the position Q. If the measurement is performed, the measured absorbance is represented by the following mathematical expression 1.

[0009]

## EQU1 ## −log (A _p / B _q ).

On the other hand, the true value of the absorbance is expressed by the following equation 2 for the position P of the measuring object 1.

[0011]

[Equation 2] −log (A _p / B _p ).

Regarding the position Q of the measuring object 1,
It is expressed by the following equation 3.

[0013]

[Equation 3] −log (A _q / B _q )

As is clear from the comparison of the equations (2) and (3) with the equation (1), when the measuring object 1 has a large change in transmittance or absorbance locally or when the moving speed of the measuring object 1 is fast. , Bq ≠ Bp, and Ap ≠ Aq. Therefore, the measured absorbance represented by Formula 1 is different from the true value represented by Formula 2 or Formula 3.

In the production of plastic films and papers to which the above photoelectric measuring device is applied, a moving speed of 100 m / min or more is common. Further, also in the case where the state of the measurement target changes with time, such as a chemical reaction, the same problem as described above occurs.

Further, in the photoelectric measuring apparatus of FIG. 9, the beat due to the interference between the sampling frequency of the light of the characteristic absorption wavelength and the light of the reference wavelength due to the rotation of the rotating disk 4 and the frequency of the unevenness of the measuring object 1 is generated. There was also a problem that it would occur.

On the other hand, in the photoelectric measuring apparatus of FIG. 10, the light from the measuring object 1 is branched to perform the simultaneous measurement, so that the interference filters 3, 3, as in the photoelectric measuring apparatus of FIG.
The problem associated with the switch of ... is solved. However, FIG.
In the photoelectric measurement device of No. 0, since a plurality of photodetectors 2a and 2b are used, there is a difference between the photodetectors 2a and 2b in relation to the light intensity due to an external factor and its output signal, that is, a change in sensitivity. However, there is a problem that correct absorbance measurement is difficult.

In particular, the sensitivity of the photodetectors 2a and 2b is related to the temperature. Light having a constant light intensity is detected by the photodetector 2
When incident on a and 2b, these photodetectors 2a,
If the temperature of 2b is constant, a constant output signal is obtained, but the outputs of the photodetectors 2a and 2b change due to so-called temperature drift when the temperature changes.

This temperature drift is caused by the photodetectors 2a and 2b.
In the photoelectric measurement device of FIG. 10, the measurement accuracy is greatly affected by the temperature change.
For example, the temperature changes due to the heat generated by the photoelectric measuring device itself when the power is turned on, the temperature changes in the early morning of the day, the daytime and the middle of the night, etc., or the temperature changes of each season in a year, etc. There is a temperature change that changes with time, and a temperature drift based on this temperature change appears as an error over time in the measurement result by the photoelectric measurement device.

It is an object of the present invention to perform simultaneous photometry using a plurality of photoelectric conversion elements on a measurement object that moves or changes its state at a relatively high speed without causing a measurement error due to a change in ambient temperature. It is an object of the present invention to provide a photoelectric measurement device capable of obtaining accurate measurement information about a measurement object without causing an error in a measurement value even when the distance and the angle of the measurement object change.

Another object of the present invention is to provide a compact photoelectric measuring device having an outer case having a cooling air circulation structure in which the temperatures of a plurality of photoelectric conversion elements are equal to each other.

[0022]

In order to achieve the above object, a photoelectric measuring device according to a first aspect of the present invention disperses light incident from an object to be measured, and electrically separates the light having a spectroscopically separated wavelength. A photoelectric conversion device for converting an electric signal by a light conversion element, processing the converted electric signal by a processing means, and detecting information contained in the measurement object, which is a fixing member of the photoelectric conversion element. The photoelectric conversion element fixed housing for fixing the photoelectric conversion element in the thermal coupling state close to each other on the same plane, and arranged inside the photoelectric conversion element fixed housing, the light incident from the measurement object is provided. While branching into a plurality of optical paths respectively corresponding to each of the photoelectric conversion elements, an optical path branching optical system for causing the branched light to enter each of the photoelectric conversion elements with an equal optical path length, That.

In order to achieve the above object, a photoelectric measuring device according to a second aspect of the present invention disperses light incident from an object to be measured and electrically separates the light having a spectroscopically separated specific wavelength.
A photoelectric conversion device for converting information into an electric signal with a light conversion element and processing the converted electric signals with a processing means to detect information contained in the measurement object, wherein light is applied to the measurement object. A light source for projecting, a light source housing for housing the light source, and a photoelectric conversion element fixing housing for fixing the photoelectric conversion elements close to each other in a thermally coupled state on the same plane by including a fixing member of the photoelectric conversion element. , Arranged inside the photoelectric conversion element fixed housing, and splits the light projected from the light source and reflected or transmitted by the measurement object to be incident on a plurality of optical paths corresponding to the photoelectric conversion elements. At the same time, an optical path branching optical system that makes the branched light enter the photoelectric conversion elements with the same optical path length is provided.

In order to achieve the above object, the photoelectric measuring device according to claim 3 is the photoelectric measuring device according to claim 1 or 2, wherein the fixing member of the photoelectric conversion element of the photoelectric conversion element fixing housing is a heat sink. Is characterized by.

In order to achieve the above object, a photoelectric measuring device according to a fourth aspect of the present invention is the photoelectric measuring device according to any one of the first to third aspects, in which a photoelectric conversion element fixing member of a photoelectric conversion element fixing housing is fixed to the photoelectric conversion element fixing member. It is characterized in that a temperature control element for controlling the temperature is attached.

In order to achieve the above object, a photoelectric measuring device according to a fifth aspect of the present invention is the photoelectric measuring device according to any one of the first to fourth aspects, wherein the optical path branching optical system is incident from an object to be measured. It is characterized by comprising a beam splitter arranged in the incident light path of light, and a reflection mirror arranged in a position where the distance from the beam splitter on each optical path branched by the beam splitter is equal.

In order to achieve the above-mentioned another object, a photoelectric measuring device according to a sixth aspect disperses light incident from an object to be measured, and separates the light having a spectroscopic specific wavelength into an electro-optical conversion element. In the photoelectric measurement device for converting the electric signals in, and processing the converted electric signals by the processing means to detect the information that the measurement object has, the outer case and the measurement object having the light A light source that projects the light source, a light source housing that houses the light source, and a cooling air circulation space between the light source housing and the light source housing, and the photoelectric conversion element is provided with a fixing member for the photoelectric conversion element. A photoelectric conversion element fixed housing that is fixed to the same plane in the thermal coupling state so as to be close to each other, and arranged inside the photoelectric conversion element fixed housing, projected from the light source and reflected or transmitted by the measurement object and incident. You An optical path branching optical system for branching light into a plurality of optical paths corresponding to the photoelectric conversion elements, respectively, and making the branched light enter the photoelectric conversion elements with the same optical path length, and the light source housing While supporting the photoelectric conversion element fixed housing and the optical path branching optical system in the outer case, the inside of the outer case is the light source housing, the photoelectric conversion element fixed housing and the housing space of the photoelectric conversion element fixed housing and the processing. And a communication hole that communicates from the circulation space of the cooling air to the accommodation space of the circuit board and a communication hole that communicates from the accommodation space of the circuit board to the light source accommodation housing. The outer case, the introduction hole of the cooling air communicating from the outside to the circulation space,
And a discharge hole for the cooling air communicating from the light source housing to the outside of the outer case, the cooling air reaching the accommodation space of the circuit board through the circulation space of the cooling air, and further the circuit board. A circulation passage for cooling air, which extends from the housing space through the light source housing to the outside of the outer case, is formed inside the outer case.

In order to achieve the another object, the photoelectric measuring device according to claim 7 is the photoelectric measuring device according to any one of claims 1 to 6, wherein the optical path branching optical system is provided inside the photoelectric element fixing housing. Is hermetically sealed.

[0029]

According to the photoelectric measuring device of the first aspect of the present invention, the plurality of photoelectric conversion elements are fixed to the fixing member of the photoelectric conversion element fixing housing in the thermal coupling state so as to be close to each other and fixed on the same plane. Light incident from the measurement object is branched into a plurality of optical paths corresponding to each photoelectric conversion element by an optical path branching optical system arranged in the conversion element fixed housing, and the light after branching has an equal optical path length. Since each photoelectric conversion element is incident on each photoelectric conversion element, even if the ambient temperature changes, the temperature drifts of the photoelectric conversion elements that are fixed to the fixing member in a thermally coupled state are equal to each other and the effect is canceled out, and the ambient temperature changes. The measurement error caused by is suppressed, the optical path length of each optical path after the branch of the light incident from the measurement object is equal, the diameter of the light beam incident on each photoelectric conversion element is equal, There is no error in the measured values due to distance fluctuations and angle fluctuations, and simultaneous photometry using multiple photoelectric conversion elements makes it possible to obtain accurate measurements for objects that move or change states at relatively high speeds. Measurement information can be obtained.

According to a second aspect of the photoelectric measuring apparatus, a light source having a light source, and light projected from the light source to the measuring object and incident from the measuring object is disposed on the photoelectric conversion element fixing housing in an optical path branching. The optical system branches the light into a plurality of optical paths corresponding to the respective photoelectric conversion elements, and the light beams after branching have the same optical path length and are close to each other in a thermally coupled state to the fixing member of the photoelectric conversion element fixing housing. Since each of them is incident on a plurality of photoelectric conversion elements that are fixed on the same plane, even if the ambient temperature changes, the temperature drift of each photoelectric conversion element that is fixed to the fixing member in a thermally coupled state is equal. The effects are canceled out, the measurement error caused by the change in ambient temperature is suppressed, and the optical path length of each optical path after the branching of the light entering from the measurement object is equal, and the optical beam entering each photoelectric conversion element is Since the diameters of the beams are equal, there is no error in the measured values even when the distance and angle of the measurement object are changed, and the light from the measurement object based on the light projected onto the measurement object from the light source Simultaneous photometry in each photoelectric conversion element makes it possible to obtain accurate measurement information about a measurement object that moves or changes its state at a relatively high speed.

According to the photoelectric measuring device of the third aspect, since each photoelectric conversion element is fixed to the heat sink, the temperature of each photoelectric conversion element becomes more uniform, and the influence of temperature drift is greatly reduced. be able to.

Further, according to the photoelectric measuring device of the fourth aspect, the temperature of the fixing member of the photoelectric conversion element of the photoelectric conversion element fixing housing is controlled to be constant by the temperature control element, so that the temperature of each photoelectric conversion element is controlled. Drift is suppressed, and highly accurate photoelectric measurement can be performed.

Further, according to the photoelectric conversion device of the fifth aspect, the light which is incident on the beam splitter from the object to be measured and is branched off is reflected by the reflecting mirrors arranged at the same distance from the beam splitter. Since it is incident on each photoelectric conversion element, the beam splitter and the reflection mirror are used, and the light after the branch of the incident light is arranged in close proximity with an equal optical path length by a simple and compact structure. It can be incident on the photoelectric conversion element.

According to a sixth aspect of the photoelectric conversion device of the present invention, the interior of the outer case has a light source accommodating housing, a photoelectric conversion element fixing housing, a photoelectric conversion element fixing housing and a circuit board housing space of the processing means. And cooling air passes through the accommodation space of the photoelectric conversion element fixing housing inside the outer case to the accommodation space of the circuit board, and further passes from the accommodation space of the circuit board to the outside of the outer case through the light source accommodation housing. Since the circulation passage of the cooling air to reach is formed, the heat generated by the light source is not transmitted to the photoelectric conversion element. Can always be maintained at a substantially constant temperature, and therefore, the photoelectric measurement device incorporating the light source can be realized compactly.

Furthermore, according to the photoelectric conversion device of the seventh aspect, since the inside of the photoelectric element fixing housing is hermetically sealed, the photoelectric element and the optical path branching optics housed inside the photoelectric element fixing housing. Since cooling air does not flow into the system, it is possible to prevent the influence of moisture contained in the cooling air on the light path branching optical system, the light incident surface of the photoelectric conversion element, and the like.

[0036]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The internal configuration of the photoelectric measurement device according to the present invention is shown in FIGS. 1 and 2.

The photoelectric measuring device 11 includes a light source 13 for projecting light to an object to be measured (not shown), a light source housing 14 for accommodating the light source 13, and light from the object to be measured, inside one outer case 12. Photoelectric conversion element 1 on which light is incident
The photoelectric conversion element fixing housing 16 to which 5a and 15b are fixed is housed.

The outer case 12 has a rectangular parallelepiped shape,
Inside the partition member 22 in which the light source 13, the light source accommodating housing 14 and the photoelectric conversion element fixing housing 16 are accommodated, the rectangular partition member 22 is fixed in parallel to the bottom plate 21 so as to face the bottom plate 21. Space and the photoelectric conversion element 15
It is divided into a space on the other side in which the circuit board 23 (see FIG. 5) of the amplifier circuit for amplifying the signals from a and 15b and supplying them to the processing circuit (not shown) is housed.

The light source housing 14 rises in the space on one side from the partition member 22 so as to surround one corner of the partition member 22 and at a right angle from one end side of the bottom plate 21 of the outer case 12. The side plate portion 14a forming a right angle with the side plate 24, the side plate portion 14b parallel to the side plate 24, and the inclined side plate portion 14c inclined with respect to the side plate 24, the partition member 22, and the side plate 24 of the outer case 12. , 25 and a cover plate 26. The light source housing 14 houses therein a lamp house 13a of the light source 13 including, for example, a halogen lamp. It is desired that the side wall of the lamp house has a high heat release efficiency, and it is preferably made of a material that is easy to heat and cool, such as stainless steel, and it is more preferable that the outer surface has a fin-shaped structure. Furthermore, the contact area of the support part and the partition member 22 is made small so that the heat generated by the light source 13 transmitted to the partition member 22 is made as small as possible. Further, a light projecting optical system 27 for projecting the light emitted from the light source 13 onto an object to be measured (not shown) is attached to the inclined side plate portion 14c of the light source housing 14. This projection optical system 27
As shown by the arrow A ₂ in FIG. 1, the light source housing 1
Light is emitted in a direction perpendicular to the inclined side plate portion 14c of No. 4.

On the other hand, the photoelectric conversion element fixing housing 16 has a space 18 for cooling air, which will be described later, between the photoelectric conversion element fixing housing 16 and the light source housing housing 14, and is parallel to the side plate 24 of the exterior case 12 from the partition member 22. The side plate member 16a that rises to the one side of the partition member 22, and the bottom plate 21 from the other end of the bottom plate 21 of the outer case 12 from the tip of the side plate member 16a.
To the other side plate 28 that rises at a right angle with respect to the flat plate fixing member 16b of the photoelectric conversion elements 15a and 15b and the side plate 25 of the outer case 12,
It is composed of 29.

The fixing members 16b of the photoelectric conversion elements 15a and 15b of the photoelectric conversion element fixing housing 16 are made of a material having good thermal conductivity such as aluminum or copper. Then, photoelectric conversion elements 15a and 15b such as photodiodes are attached to the fixing member 16b in a good thermal coupling state with the fixing member 16b, and
Fixed close to each other. Inside the photoelectric conversion element fixed housing 16, an optical path branching optical system 31 is arranged on the partition member 22. The structure of this optical path branching optical system 31 is shown in FIG.

The optical path branching optical system 31 includes an optical path branching block 32. As shown in FIG. 3, the optical path branching block 32 has an L-shape including two optical path block portions 32a and 32b which are connected to each other at right angles to each other. Inside the optical path branching block 32, a half mirror as a beam splitter is formed in the coupling portion of the two optical path block portions 32a and 32b with an angle of 45 degrees with respect to each optical axis of the optical path block portions 32a and 32b. 33 is arranged, and reflection mirrors 34a and 34b are arranged at positions equidistant from the half mirror 33, respectively. These reflection mirrors 34a, 34
Each of b is the two optical path block portions 34a and 34b.
Is inclined at an angle of 45 degrees with respect to the plane including the optical axis of
The respective lights that are respectively incident after being branched by the half mirror 33 are reflected in the same direction in the direction perpendicular to the surface.

Therefore, the light source 1 shown in FIGS. 1 and 2 is used.
When the light projected from 3 and reflected or transmitted by an object to be measured (not shown) enters the optical path branching block 32 through the entrance opening 35 provided in the optical path branching block 32, as shown by an arrow A ₃ in FIG. The light from the object to be measured travels by the half mirror 33 along the optical path along the optical axis of one optical path block portion 32a as shown by arrow A ₄ , and the optical axis of the other optical path block portion 32b. It is branched into a light traveling as indicated by arrow a ₅ along. Then, the light traveling along the optical path along the optical axis of one optical path block portion 32b is reflected by the reflecting mirror 34a by an arrow A ₆ in a direction perpendicular to the surface including the optical axes of the two optical path block portions 32a and 32b. It is reflected in the direction shown. Further, light traveling the optical path along the optical axis of the optical path block portion 32b of good enough, at the reflecting mirror 34b, is reflected in the direction indicated by the arrow A ₇ in the same direction as the light reflected by the reflecting mirror 34a.

The light reflected by the reflection mirror 34a is
The light enters the photoelectric conversion element 15a fixed to the fixing member 16b of the photoelectric conversion elements 15a and 15b of the photoelectric conversion element fixing housing 16 shown in FIGS. 1 and 2 through the emission opening 36a provided in the optical path branching block 32. Similarly, the light reflected by another reflection mirror 34b passes through another emission opening 34b provided in the optical path branch block 32,
The light is incident on another photoelectric conversion element 15b fixed to the fixing member 16b shown in FIGS. Photoelectric conversion element 1
5a and 15b are two optical path block parts 32a and 32b.
Of the fixing member so that the centers of the photoelectric conversion surfaces thereof are aligned with the optical axes passing through the emission openings 36a and 36b of the optical path branching block 32 at positions equidistant from the surface including the optical axes of. It is fixed to 16b.

With the above configuration of the optical path branching optical system 31,
The light branched by the half mirror 33 enters the photoelectric conversion elements 15a and 15b with the same optical path length. FIG. 4 schematically shows this. Although not specifically shown, a bandpass filter and a reference for transmitting light of the measurement wavelength to the middle of the optical path from the half mirror 33 to the photoelectric conversion elements 15a and 15b or to the photoelectric conversion elements 15a and 15b themselves. Bandpass filters that transmit light of a wavelength are arranged.

Referring back to FIGS. 1 and 2, the partition member 22 for partitioning the inside of the outer case 12 into a space on one side and a space on the other side accommodates the photoelectric conversion element fixing housing 16. There is a communication hole 41 communicating from the circulation space of the cooling air in the space on the one side to the space on the other side in which the circuit board 23 (see FIG. 5) is accommodated, and the light source accommodation from the space on the other side. A communication hole 42 that communicates with the housing 14 is provided. In addition, as shown in FIG.
A cooling air introduction hole 43 for introducing cooling air from the outside into the distribution space is provided, and the cooling air introduced into the outer case 12 is provided in the outer case 12.
A cooling air discharge hole 44 for discharging the cooling air to the outside.

Inside the outer case 12, as shown by arrows A ₁₁ to A ₁₇ in FIG. 5, the cooling air introduced into the outer case 12 through the cooling air introduction hole 43 is fixed to the photoelectric conversion element fixing housing 16. While being cooled, the cooling air is introduced into the circulation space 18 on one side of the partition member 22, and the communication hole 41
And the partition member 2 that passes through the circuit board and accommodates the circuit board 23.
2 to the space on the other side, and further from this space on the other side to the inside of the light source housing 14 through the communication hole 42 formed in the partition member 22, and after cooling the light source 13, the cooling air is exhausted. A circulation passage for the cooling air discharged to the outside of the outer case 12 through the hole 44 is formed.

Due to the circulation passage of the cooling air, the heat generated by the light source 13 is not transmitted to the photoelectric conversion elements 15a and 15b. Therefore, the photoelectric conversion elements 15a and 15b
Even if the light source 13 is incorporated in the same outer case 12, the temperature of the photoelectric conversion elements 15a and 15b can always be maintained at a substantially constant temperature due to the contact of the cooling air introduced into the outer case 12.

40 l / min and 55 l / min of cooling air are circulated in the cooling air circulation passage to turn on the light source 13, and the outer case 1 is turned on.
The measurement result of measuring the temperature of each part of No. 2 is shown in FIG. In FIG. 6, a curve h ₁ is a temperature measurement value of a temperature sensor installed near the side wall of the lamp house 13 a indicated by a cross mark 51, and a curve h ₂ is a lamp indicated by a cross mark 52. The curve h ₃ is the temperature measurement value of the temperature sensor installed in the partition member 22 near the support portion of the house 13a, and the curve h ₃ is in the space on the other side of the partition member 22 in which the circuit board 23 in the outer case 12 is accommodated. The temperature measurement value of the temperature sensor arranged at the position indicated by a cross mark 53 is shown, and the curve h ₄ is indicated by a cross mark in the cooling air circulation space on one side of the partition member 22 in the outer case 12. It is the temperature measurement value of the temperature sensor arranged at the position shown with 54. The material of the lamp house 13a is stainless steel having a thickness of 0.1 mm, and the outer case 12 has dimensions of height × width × depth = 100 mm.
It was × 130 mm × 60 mm.

From FIG. 6, even when the power source of the light source 13 is turned on or off, the cross mark 5 in the cooling space of the outer case 12 is used.
It can be seen that at the position of 4, there is almost no temperature change.
Therefore, it can be seen that the temperature drift of the photoelectric conversion elements 15a and 15b is suppressed. Moreover, since the photoelectric conversion elements 15a and 15b are fixed to the same fixing member 16b in a thermally coupled state with each other, their temperature drifts become equal and their influences are canceled out, so that the temperature drifts are suppressed as described above. Combined with the above, the measurement error is reduced.

Also, the photoelectric conversion element 1 is projected from the measuring object by projecting it from the light source 13 onto the measuring object (not shown).
The light beams 5a and 15b respectively have the same optical path length as the light beams after being branched by the half mirror 33 of the optical path branching optical system 31 and have the above-mentioned photoelectric conversion elements 15a and 15b.
b. Therefore, the diameters of the light beams incident on the photoelectric conversion elements 15a and 15b become equal,
There is no error in the measured value even when the distance to the measurement object changes or the angle changes.

As a result, the two photoelectric conversion elements 15a,
Each photoelectric conversion element 15 of the light from the measuring object based on the light projected from the light source 13 onto the measuring object using 15 b
Since it is possible to perform simultaneous photometry in a and 15b, accurate measurement can be performed on a measurement object that moves or changes its state at a relatively high speed without being affected by distance fluctuations, angle fluctuations, or temperature fluctuations with the measurement object. You can get information.

In the above embodiment, the light split by the half mirror 33 is reflected by the reflecting mirrors 34a and 34b as shown in FIG.
The two optical path block portions 32a and 32b are reflected in the directions perpendicular to the planes including the optical axes in the directions indicated by the arrows A ₆ and A ₇ , but the reflection mirrors 34a and 34b and the photoelectric conversion elements 15a, In the fixing member 16b of 15b, the light branched by the half mirror 33 is in the plane including the optical axes of the two optical path block portions 32a and 32b (see FIG. 3), and the arrow A ₆ ′ in FIG. As indicated by A ₇ ′, they may be arranged so as to enter the photoelectric conversion elements 15 a and 15 b. In this case, the reflection mirrors 34a and 34b
The photoelectric conversion elements 15a and 15b are the half mirror 3
It is set so that the optical paths of the light that is branched at 3 and enters the photoelectric conversion elements 15a and 15b are equal.

Further, in the above embodiment, one half mirror 33 is used to split the light from the object to be measured into two lights, which are measured by the two photoelectric conversion elements 15a and 15b. However, for example, as shown in FIG. 8, using two (or more) half mirrors 33a, 33b (and 33c) and three (or more) photoelectric conversion elements 15a, 15b, 15c, It is also possible to perform photoelectric measurement of the measurement light and the reference light.

Further, in the above-mentioned embodiment, the photoelectric conversion elements 15a and 15b are fixed to the plate-shaped fixing member 16b of the photoelectric conversion element fixing housing 16, but instead of the fixing member 16b, a large number of heat radiations are used. The photoelectric conversion elements 15a and 15b may be incorporated in a heat sink having fins. By doing so, the photoelectric conversion elements 15a,
The temperature of 15b is more effectively controlled by the cooling air having a substantially constant temperature through the heat sink, so that the temperature drift of the photoelectric conversion elements 15a and 15b is significantly suppressed.

Furthermore, in the above-described embodiment, a temperature control element such as a Peltier element is attached to the flat plate-shaped fixing member 16b of the photoelectric conversion element fixing housing 16 or the heat sink, and is attached to the fixing member 16b and the heat sink. Alternatively, the temperatures of the photoelectric conversion elements 15a and 15b may be controlled to be constant. By doing so, the temperature drift of the photoelectric conversion elements 15a and 15b can be further suppressed.

In the above embodiment, the light source 1 is placed in the outer case 12.
Although the photoelectric measurement device having the built-in 3 has been described, the present invention can be applied to a device in which the light source is not built in the outer case when measuring the radiation temperature or the like of the measurement target. Also in this case, an error does not occur in the measurement value due to the distance variation and the angle variation with the object to be measured, and the temperature drift of the photoelectric conversion element is canceled to perform the photoelectric measurement with less measurement error due to the temperature variation. be able to.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an internal structure of an embodiment of a photoelectric measurement device according to the present invention.

FIG. 2 is a partially cutaway perspective view of the photoelectric measurement device viewed from a direction different from FIG.

FIG. 3 is a perspective view of an optical path branching optical system.

FIG. 4 is a schematic diagram for explaining the optical path branching optical system of FIG.

5 is an explanatory diagram of a circulation path of cooling air that circulates inside the photoelectric measurement device of FIGS. 1 and 2. FIG.

FIG. 6 is measurement data of the temperature of a portion indicated by a mark X in FIG.

FIG. 7 is an explanatory diagram of a modified example of the branch optical system of the photoelectric measurement device according to the present invention.

FIG. 8 is an explanatory diagram of a branch optical system of a photoelectric measurement device according to the present invention when performing photoelectric measurement using three photoelectric conversion elements.

FIG. 9 is an explanatory diagram of a conventional photoelectric measurement device.

FIG. 10 is an explanatory view of another conventional photoelectric measurement device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Photoelectric measuring device 12 Outer case 13 Light source 14 Light source housing 15a Photoelectric conversion element 15b Photoelectric conversion element 16 Photoelectric conversion element fixed housing 16a Side plate member 16b Fixing member 18 Distribution space 21 Bottom plate 22 Partition member 23 Circuit board 27 Projection optical system 31 Optical path branching optical system 32 Optical path branching block 32a Optical path block part 32b Optical path block part 33 Half mirror 34a Reflecting mirror 34b Reflecting mirror 41 Communication hole 42 Communication hole 43 Cooling air introducing hole 44 Cooling air discharging hole 44

Claims (7)

[Claims] 1. A light incident from a measurement object is dispersed, each of the separated light having a specific wavelength is converted into an electric signal by an electro-optical conversion element, and the converted electric signal is processed by a processing means. A photoelectric conversion device for detecting information contained in the object to be measured, comprising a fixing member for the photoelectric conversion element, and fixing the photoelectric conversion elements in proximity to each other in a thermally coupled state on the same plane. The photoelectric conversion element fixed housing to be, and is disposed inside the photoelectric conversion element fixed housing, the light incident from the measurement object is branched into a plurality of optical paths corresponding to the photoelectric conversion elements, respectively, after branching An optical path branching optical system for causing light to enter the photoelectric conversion elements with the same optical path length. 2. Light incident from a measurement object is dispersed, each of the separated light having a specific wavelength is converted into an electric signal by an electro-optical conversion element, and the converted electric signal is processed by a processing means. A photoelectric conversion device for detecting the information that the measurement object has, a light source that projects light onto the measurement object, a light source housing that houses the light source, and the photoelectric conversion element fixed A photoelectric conversion element fixed housing that is provided with a member and fixes the photoelectric conversion elements in the thermal coupling state to be close to each other and fixed on the same plane, and is disposed inside the photoelectric conversion element fixed housing and projected from the light source to perform the measurement. The light reflected or transmitted by the object and incident on it is branched into a plurality of optical paths corresponding to the photoelectric conversion elements, respectively, and the branched light is incident on the photoelectric conversion elements with the same optical path length. Photoelectric measuring apparatus characterized by comprising an optical path branching optical system for. 3. The photoelectric measurement device according to claim 1, wherein the fixing member of the photoelectric conversion element of the photoelectric conversion element fixing housing is a heat sink. 4. The temperature control element for controlling the temperature of the photoelectric conversion element fixing member of the photoelectric conversion element fixing housing is attached to the fixing member.
The photoelectric measurement device according to any one of 1. 5. The optical path branching optical system comprises a beam splitter arranged in an incident optical path of incident light entering from an object to be measured, and a distance from the beam splitter on each optical path branched by the beam splitter. The photoelectric measuring device according to claim 1, wherein the photoelectric measuring device comprises reflection mirrors arranged at the same position. 6. The light incident from the object to be measured is dispersed, the dispersed light having a specific wavelength is converted into an electric signal by an electro-optical conversion element, and the converted electric signal is processed by a processing means. And is a photoelectric measurement device for detecting the information that the measurement object has, an outer case, a light source that projects light on the measurement object,
A light source housing that houses the light source and a cooling air circulation space are arranged between the light source housing and the light source housing, and the photoelectric conversion element is provided with a fixing member so that the photoelectric conversion elements are close to each other in a thermally coupled state. Then, the photoelectric conversion element fixing housing fixed on the same plane, and arranged inside the photoelectric conversion element fixing housing, the light projected from the light source and reflected or transmitted by the measurement object is incident on each of the photoelectric conversion elements. While branching into a plurality of optical paths respectively corresponding to the conversion element, an optical path branching optical system that makes the branched light respectively incident on the photoelectric conversion element with an equal optical path length, and the light source housing.
The photoelectric conversion element fixing housing and the optical path branching optical system are supported in the outer case, and the inside of the outer case is the light source accommodating housing, the photoelectric conversion element fixing housing and the accommodating space of the photoelectric conversion element fixing housing, and the processing means. And a communication hole that communicates from the circulation space of the cooling air to the accommodation space of the circuit board and a communication hole that communicates from the accommodation space of the circuit board to the light source accommodation housing. And a partition member that is
The cooling air has an introduction hole that communicates with the circulation space from the outside, and a discharge hole for the cooling air that communicates with the outside of the exterior case from the light source housing, and the cooling air is the cooling air. A circulation passage of cooling air is formed inside the exterior case, which reaches the accommodation space for the circuit board through the circulation space, and further extends from the accommodation space for the circuit board to the outside of the exterior case through the light source accommodation housing. A photoelectric measurement device characterized by the above. 7. The photoelectric measuring device according to claim 1, wherein the inside of the photoelectric element fixing housing is hermetically sealed.