JPH0337529A - Radiation thermometer - Google Patents

Abstract

PURPOSE:To clarify the size required for a material to be measured for accurate temperature measurement by measuring a distance to the material to be measured, and displaying a temperature measuring region determined by the measuring distance by utilizing a finder based on the measured result. CONSTITUTION:Two concentric circular indexes 40 and 41 are marked in a field of a view 36 of a finder of a focal point plate 33. A region corresponding to the small-diameter index 40 is a range indicated by broken lines V0 and V0. The lines V0 and V0 are overlapped with lines T1 and T2 of a target cone at a focal distance L0 wherein a temperature measuring distance becomes the minimum value. Meanwhile, a region corresponding to the large-diameter index 41 is a range indicated by dashed lines V1 and V2. The lines V1 and V2 and lines T1 and T2 are intersected at a specified front defocus distance L1 and a rear defocus distance L2. When, temperature is measured, the required size of a material to be measured viewed through the finder is set as follows: When the measuring distance (x) is the focal distance L0, the size is made to be the size of the index 40. When L1<=x<L0 and L0<x<=L2, the size is made to be the size of the index 41. In this way, the required measuring size can be judged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an IR thermometer that receives infrared rays emitted from an object to be measured and determines the temperature of the object from the amount of received light.

[Conventional technology]

The temperature of the object to be measured can be measured without contact by concentrating infrared radiation from the object to be measured using a condenser such as a lens, and receiving the light with a temperature sensor using a photoelectric conversion element. Radiation thermometers are generally known. In such radiation thermometers, it is necessary to confirm the temperature measurement area of the object to be measured, especially when the humidity measurement optical system is of a fixed focus type and is configured to be able to measure temperature in a relatively small area. be done.

Conventionally, in this type of radiation thermometer, for example, Japanese Patent Application Laid-Open No. 63
As shown in Publication No. 145929, in addition to the temperature measurement optical system that collects and receives infrared rays emitted from the object to be measured, there is also an aiming system that emits a parallel beam of visible light to the measuring point of the object to be measured. By providing an optical system, the measurement location can be easily
There is something that allows you to do this.

In addition, as shown in Japanese Patent Application Laid-open No. 63-255630, a temperature measuring optical system is also used that uses a spora 1 to a marker device that irradiates a light beam from a light source onto an object to be measured through a mask and an objective lens. By attaching it to the system unit I~ and adjusting the position and distance of the temperature measuring optical system unit to the object to be measured until the image of the tip from this spot marker device appears sharply on the object to be measured, There are also known devices that allow the user to confirm the measurement location and adjust the focus.

[Problem to be solved by the invention]

According to the former of the conventional devices shown in the above publications, although it is possible to aim, it is not possible to adjust the focus, and it is not possible to check the temperature measurement area if the focus is out of focus. It becomes difficult to confirm whether the temperature is being measured properly. In other words, with this type of radiation thermometer, if the object to be measured is smaller than the temperature measurement area, radiation from the background other than the object will also be received, making the temperature measurement inaccurate. In order to confirm whether the object is in a warm state, it is necessary to know the relationship between the size of the object and the temperature measurement area.

However, as will be explained in detail later, the temperature measurement area changes depending on the distance between the radiation thermometer and the object to be measured, and if the temperature measurement area deviates from the focused distance, the temperature measurement area will become larger. However, the temperature measurement area could not be confirmed with the above device.
This may result in incorrect temperature measurement.

In addition, with the latter device, it is possible to check the temperature measurement area at the focused distance by focusing, but it is necessary to adjust the position of the optical system unit relative to the object to be measured in order to adjust the focus. Because of this, the work is troublesome. Moreover, since the image of the light irradiated onto the object to be measured from the spot marker device is visually inspected, it is not easy to focus, and the image becomes difficult to see, especially if the object to be measured itself is bright. There is a problem that it becomes difficult to focus and check the humidity measurement area.

The present invention has been made in view of the above, and it is possible to easily confirm the temperature measurement area according to the distance based on the measurement of the distance to the object to be measured, and even at a distance that is out of focus. An object of the present invention is to provide an OA thermometer that allows a user to clearly recognize whether or not the temperature is being measured properly.

(Means for Solving the Problems) The present invention provides a temperature measurement optical system in which a light condenser that collects 111% light from an object to be measured and a temperature measurement sensor consisting of a photoelectric conversion element are provided in a fixed arrangement. , a distance measuring means for measuring the distance to the object to be measured, and a finder system for observing the object to be measured, and displaying the area whose temperature is measured by the temperature measuring optical system according to the output of the distance measuring means. and area display means for displaying the area.

In this configuration, the distance measuring means includes means for irradiating the measured object with a beam of light in a wavelength range different from the wavelength range in which the temperature is measured by the temperature sensor, and means for condensing the reflected light onto a predetermined surface. It is preferable that the image forming apparatus comprises an image forming means and a position sensor located on the predetermined plane to detect the image forming position.

In addition, the area display means provides a plurality of indicators of different sizes in the finder, and indicates in accordance with the output of the distance measuring means which indicator range the temperature measurement area is within. It is preferable that the temperature be indicated by indicating means separately provided in the finder, or that the size of the index indicating the area to be measured may be changed in accordance with the output of the distance measuring means.

Further, it is preferable to use an optical distance measuring means and to arrange the temperature measuring optical system, the distance measuring means, and the finder system incorporating the area display means so that their respective optical axes coincide with each other.

[Effect]

According to the present invention, based on the measurement of the distance to the object to be measured,
The area whose temperature is to be measured is appropriately displayed, and the required size of the object to be measured for accurate temperature measurement is clarified by this display.

Furthermore, if a distance measuring means is used that detects the imaging position of the reflected light by projecting a beam of light in a wavelength range different from that measured by the temperature sensor onto the measured object, the temperature measurement will be affected. without affecting
The distance to the object to be measured is measured optically.

In addition, the area display means indicates in which of the plurality of indicators provided in the finder the temperature measurement area is located, or changes the size of the indicator depending on the distance measurement result. If the temperature is changed according to the index, the area whose temperature is measured at various distances can be confirmed by the index.

When the temperature measuring optical system, the distance measuring means, and the finder system including the area display means are arranged with their optical axes aligned, their optical paths are aligned.

<Example> First, the principle applied to the present invention will be explained with reference to FIGS. 1 to 3.

Figure 1 shows the basic configuration of a fixed focus type temperature measurement optical system, and
It conceptually shows temperature measurement areas according to the distance to the object to be measured. In this figure, 1 is a condensing lens, 2 is a light receiving surface of a temperature sensor, and emitted light from an object to be measured 3 is collected by the lens 1 and received by the temperature sensor. The distance between the lens 1 and the light-receiving surface 2 is constant, and the light-receiving surface 2 receives light that has passed through a mask (fixed aperture) of a certain size (not shown). The area where the emitted light is received by the light-receiving surface 2 on the surface where the measurement object 3 is located changes depending on the distance from the measurement object 3 to the lens 1, and corresponds to the line T1. This is the area between T2. A figure showing a temperature measurement area according to such a distance is hereinafter referred to as a target cone. Also, with reference to the positions of the lens 1 and the light-receiving surface 2, the object-side surface at the in-focus position is the focus plane FO, and the object-side surface at the out-of-focus position is the telefocus plane D. , the distance between the lens 1 and the focus surface FO is called a focus distance Lo, and the distance between the lens A and the defocus surface DF is called a defocus distance 1i111L.

The focus distance 111Lo and the measurement diameter (diameter of the temperature measurement area) D at this distance are specified by the temperature measurement optical system, and the measurement diameter d as the defocus distance is determined by the focus distance 1tilLo and the measurement diameter at this distance. It is determined as follows from the measurement diameter and the diameter of the lens 1.

d-(D+A)XL/Lo-A (when L≧10)
d=A-(A-D)XL/Lo (when L≦[0)
Therefore, the target cone can be determined in advance. As is clear from the above formula and diagram, the measurement diameter becomes the minimum (d>D>) at the focus distance.

By the way, if the object to be measured 3 is smaller than the measurement diameter, the radiation from the back plate other than the object to be measured will also be received by the temperature sensor, making the temperature measurement inaccurate. In order to accurately measure the temperature by receiving only the light beam, it is necessary that the diameter of the object 3 to be measured is equal to or larger than the measurement diameter. Therefore, for the object to be measured 3 whose size is equal to the minimum measurement radius, the measurement distance must be set to the focus distance LO, and even if the object to be measured 3 is at the defocus distance ( The size is the measured diameter at that position 6
If the temperature is above, accurate temperature measurement can be performed.

Therefore, the present invention measures the measurement distance to the object to be measured 3,
Based on this measurement result, the temperature measurement area determined by the measurement distance is plotted using a finder.

Note that if the condition that the size of the object to be measured 3 is greater than or equal to the measurement diameter is satisfied, a temperature measurement value corresponding to the temperature of the object to be measured 3 will be obtained regardless of the measurement distance, and the output of the temperature measurement optical system will be There is no need to correct it by the measured distance.

To explain this principle, if synchrotron radiation in the range of a small solid angle dω emitted from a point radiator is irradiated onto a small area ds, then the radial flux P, the radiant intensity T, and the radial illuminance E The relationship between them is as follows: 1=dP/dω E=dP/ds= I-dω/ds, and if the distance between the radiator and the irradiation surface is (, and the inclination of the irradiation surface is θ, then [dω-ds- cos θ/(2), so E=I−cos θ/(2
) when viewed from an angle θ with respect to the normal line, the radiance B in this direction, the radiant intensity 1r in this direction, and the radial flux 1P are as follows: B=d I r/ (ci 5−CO3θ) =dP/(
There is a relationship of dω・ds−cosθ〉. If the radiator is a completely diffusing surface, the radiance B is constant regardless of direction.

In the temperature measurement optical system shown in Fig. 2, all the radiation flux passing through the mask 4 in front of the light reception surface 3 of the temperature measurement sensor is directed to the light reception surface 3, and the image of the object to be measured is is imaged at the position of the mask 4, if the radiance of the object to be measured (assumed to be negative) is 81, and the transmittance of the lens 2 is τ, then the radiance of the image at the mask position B2 is uniform within the paraxial range as [B2-τB1]. Therefore,
If the angle when looking at lens 2 from the mask position is constant,
The radiant flux P that passes through the mask 4 and reaches the light-receiving surface 3 has a value that corresponds to the radiance B1 of the object to be measured, regardless of the distance to the object. Furthermore, when the image formation position is shifted from the mask surface as shown in Fig. 3, it is sufficient to consider the image 5 as a new radiation source, and the irradiance E at any point A within the mask is determined by the minute area of the image. 2 ds2, the image radiance (-like) is 82, the distance between the image and point A is Q2, and the tilt with respect to the optical axis is θ, then E=fdi
−cosθ, / l 22 =, rB2 ◆ds2 cosθ◆ COSθ/'
Q22=B2 ・f (cos2 θ/ff22)
・It becomes ds2. Here, if the area of lens 1 with respect to ds2 is dso, and the distance from lens 1 to point A is (0), then [ds2/dso = lQ2/ao)2], so E=82・f(C082θ10o2)− ds(1=82
・Ω becomes (Ω is the solid angle when looking at the lens from point A). Therefore,
If Ω depending on the position of point A is constant, the irradiance E has a value corresponding to the radiance B2 of the image. If the size of the image is greater than or equal to the size corresponding to Ω at the imaging position, the above equation holds, and the radiance B2 of the image has a certain relationship with the radiance B1 of the object to be measured. (82-τ and 1>), so as long as the condition that the size of the object to be measured is greater than or equal to the measurement diameter is satisfied, the radiant flux of the light passing through the mask 4 and reaching the light-receiving surface 3 is Regardless of the distance from to the object to be measured, the value corresponds to the radiation degree B1 of the object to be measured.

Next, the specific structure of the radiation thermometer according to the embodiment of the present invention will be explained with reference to FIGS. 4 to 8.

Figure 4 shows the entire radiation thermometer. The iFI thermometer includes a temperature measuring optical system 10, a distance measuring system 20, and a finder system 30. The temperature measurement optical system 10 includes a condenser mirror 11 as a condenser, and a temperature measurement sensor 12 consisting of a photoelectric conversion element.
It is equipped with The condensing mirror 11 corresponds to the condensing lens 1 in FIG. 1, and is fixed to the casing 13 so as to face the object to be measured (not shown in FIG. 4). The temperature sensor 12 is arranged at a certain distance from the condensing mirror 11 so that its center is located on the optical axis, and is fixed to the condensing mirror side portion of the cylindrical body 14 provided inside the casing 13. has been done. Then, infrared radiation from the object to be measured, indicated by arrow a, is collected by a condenser mirror 11 and received by a temperature sensor 12, and the output of this temperature sensor 12 is amplified and amplified by an electric circuit (not shown). RI24 is arrayed and used as temperature information.

The distance measuring system 20 has an infrared LED 21 and a lens 22 for projecting light on the side of the object to be measured inside the cylinder 14, and also has an object inside a cylinder 26 installed parallel to the cylinder 14. A light receiving lens 23 and a position sensor 24 are installed on the side of the object to be measured.
It is equipped with The light projection lens 22 also serves as an objective lens for the finder system 30, and an infrared LED 21 is provided near the focal point of this lens 22, and an infrared LED 2
1 and the lens 22, a mirror (or half mirror) 25 that transmits infrared rays and reflects visible rays is arranged at an angle of 45° to the optical axis.

Then, as shown by the arrow, an infrared beam is projected from the infrared LED 21 onto the object to be measured through the lens 22, and the reflected light is focused by the light receiving lens 23 and formed into an image on the position sensor 24. The distance to the object to be measured is measured based on the imaging position.

The infrared rays emitted from the infrared LED 21 to the object to be measured are received by the temperature sensor 12.
By setting the wavelength range to be different from that of the temperature measuring optical system 10
Even if the temperature measurement by the distance measurement system 20 and the distance measurement by the distance measurement system 20 are performed at the same time, the two do not influence each other. It should be noted that if the timing of the light projection by the distance measuring system 20 and the timing of the temperature measurement are shifted, the infrared rays projected by the distance measuring system 20 and the infrared rays used to measure the temperature may be in the same wavelength range. Further, the distance measuring system is not limited to that shown in this embodiment, and may be one using other optical distance measuring means or known ultrasonic waves.

Further, the finder system 30 directs visible light from the object to be measured through the lens 22 and mirror 25 to the cylindrical body 2.
This portion is provided with a mirror 31 arranged at an angle of 45°, a relay lens 32, a focusing plate 33, and an eyepiece 34. Then, as shown by arrow C, the measurement point is confirmed by observing the image formed on the focusing plate 33 through the lens 22, the mirror 25° 31, and the relay lens 32 through the eyepiece 6. is now possible. The finder optical system is pan-focused.

The focusing plate 33 in the finder system 30 is provided with area display means for displaying the area where the temperature is to be measured, as will be described later. The area is displayed in accordance with the measured distance by a display control signal output from the control circuit 35 receiving the output of the position sensor 23 of the distance measuring system 20 to the area display means.

The light emitting side of the distance measuring system 20, that is, the portion consisting of the infrared ray ED 21, the mirror 25, and the lens 22, is arranged so that its optical axis coincides with the optical axis of the temperature measuring system 10, and the lens 22 also serves as the objective lens of the finder system 30, so that the optical axis of the finder system 30 also coincides with the optical axis of the temperature measuring system 10 in the range from the object to be measured to the lens 22 and the mirror 25. By aligning the optical axes in this way, it is possible to prevent errors in measurement by the distance measuring system 20 and area display in the finder system 20, and the overall structure is made compact.

FIG. 5 shows an example of area display means provided on the focus plate 33 of the finder system 30. This area display means includes a plurality of indicators written on the focus plate 33 and a plurality of LEDs as an indicator indicating which indicator the temperature measurement area is within. Two indicators 40.4 are arranged concentrically within the viewfinder field 36 of the plate 33.
1 is written, and a red LED 42, a green LED 43, and a red LED 44 are displayed below the viewfinder field of view 36.
Three LEDs are provided. In response to a signal from a control circuit 35 receiving an output from the position sensor 24, the LEDs 42 to 44 are selectively turned on depending on the distance of the object to be measured.

The visual field area corresponding to each index 40.41 above is carved on the target cone so that the relationship shown in FIG. 6 is obtained.
The size of each index 40.41 is set. That is, the area corresponding to the small diameter index 40 is the range shown by the broken lines Vo, Vo, and the focus distance "0" where the temperature measurement area is the minimum is the line VO, V.

8 and target cone lines T1 and T2 are set to overlap. On the other hand, the area corresponding to the large-diameter index 41 is a range indicated by dashed-dotted lines V+ and Vi, and has a predetermined front defocus distance 1llIL1 and rear defocus distance 1
1L2 and line V1. It is set so that V+ intersects with lines T+ and T2.

With this setting, if the measurement distance to the object to be measured x is the focus distance and 0, the temperature measurement area will be equal to the area corresponding to the index 40, and the measurement distance However, if [1≦X≦2], the temperature measurement area will be within the area corresponding to the index 41.Then, in order to measure the temperature, the size of the object to be measured will be within the temperature measurement area. The required measurement size of the object to be measured as seen in the finder can be determined by using the focus distance L of 11x for measurement.
o, the size of the index 40 is set, and [L+ ≦X〈“0
] and [Lo<x≦12], if the size of the index 41 is set, the required measurement size can be determined based on the index 40.41.

Therefore, depending on the measurement distance detected by the position sensor 24, for example, the ED42 is set as shown in Table 1 below.
By performing the display according to ~44, the index 40.41
It is designed to indicate which of the following criteria should be used to check the required size.

According to the radiation thermometer of this embodiment, the distance measuring system 20
Based on the distance measurement by
It becomes N. At this time, if the object to be measured viewed through the F0-inder completely includes the small-diameter index 40, the temperature of the object to be measured by the temperature measurement optical system 10 will be accurately measured (only the radiation from the object will be measured). light is being received). Therefore, at this time, temperature can be accurately measured using the minimum measurement diameter.

Also, if the measurement distance is [“1≦x<Lo] or [Lo<Lo]
In the range of x≦2, green LED43 and red LED
Either D42 or D44 turns ON, and at this time,
If the object to be measured viewed through the finder completely includes at least the large-diameter index 41, the temperature of the object to be measured by the measuring optical system 10 will be accurately measured. Therefore, if the measurement distance is within the above range, it can be determined whether accurate temperature measurement is possible even if the object is out of focus.

FIG. 7 shows another embodiment of the area display means incorporated into the finder system 30. In this embodiment, a plurality of concentric rings 50 to 53 are formed of liquid crystal as indicators provided within the viewfinder visual field 36. Then, by using this liquid crystal, one of the rings 50 to 53 is selectively displayed on its own according to the measured distance to the object to be measured, and by using the displayed ring as an index, the index can be set according to the measured distance. I am trying to change the size of the . In this case as well, an index is determined according to the measurement distance based on the relationship between the field of view corresponding to the ring and the target cone.
53 are shown in FIG. 6 by lines Vo, Vo, Vio, Vlo, l! ;lV2[+, V2O
, the lines V 30 , V 30 teso h are shown, and each of these includes the temperature measurement area.The measurement distance range is from Lo, Lu to L 12, "21 to L
22, L31 to 132, by displaying an index according to the measurement distance X as shown in Table 2 below, the displayed index becomes the required measurement size of the object to be measured as seen through the finder.

Table 2 The plurality of concentric rings made of the liquid crystal described above can more accurately indicate the required measurement size of the object to be measured according to the measurement distance, as the interval between them is reduced and the number thereof is increased.

Further, as another example of using a liquid crystal as the area display means, a large number of dot-shaped liquid crystals may be arranged, and a ring serving as an index may be displayed with a suitable driver depending on the measurement distance.

In addition, if an index is provided within the viewfinder field of view 12, as shown in FIG. When is within the focus distance, the LED 61 of a specific color is lit, and when it is out of the A-cus distance, the LED 61 of a specific color is lit, for example, in a range close to the focus distance so that the extent of the deviation can be determined. L of
It is also possible to adjust the measurement distance to the focus distance and find out the required measurement size by lighting up the ED or blinking the LED 61 at a period corresponding to the deviation from the focus distance. However, in this case, it is necessary to adjust the measurement distance so that it becomes the focus distance, and on the other hand, as in the embodiment shown in FIG. If the temperature measurement area is shown within which range, or if the size of the displayed index is changed as in the embodiment shown in FIG. Not only can you check the minimum measurement diameter, but you can also check the required measurement size 4 even at a defocus distance, and if the object to be measured is larger than the required size, you can accurately measure the temperature without adjusting the focus distance.

〔Effect of the invention〕

As described above, according to the radiation thermometer of the present invention, the distance to the object to be measured is measured by the distance measuring means, and the temperature measurement area is displayed on the output by the area display means. The corresponding temperature measurement area can be easily confirmed, and the necessary measurement size of the object to be measured for accurate temperature measurement can be known. Therefore, it is easily possible to accurately measure temperature using the minimum measurement diameter by measuring the distance that is in focus, and it is also possible to know the required measurement size even at a distance that is not in focus.

Furthermore, the distance can be measured by projecting a beam of light in a wavelength range different from the wavelength range measured by the temperature sensor onto the object to be measured, and detecting the imaging position of the reflected light using a position sensor. If this is done, the above distance can be detected with high accuracy without affecting the temperature measurement. In addition, a plurality of indicators may be provided in the finder 5 as the area display means to indicate which indicator the temperature measurement area is located in according to the distance measurement results, or the size difference of the indicators may be used to display the distance measurement results. If it is changed accordingly, the measured size can be clearly known at various measurement distances. In addition, while using optical distance measuring means,
By arranging the temperature measuring optical system, the distance measuring means, and the finder system incorporating the area display means so that their optical axes are aligned, the entire system can be made compact, and the distance measurement and area display means can be made more compact. This has effects such as being able to prevent errors from occurring in the display and improve accuracy.

[Brief explanation of drawings]

1 to 3 are explanatory diagrams of the principles applied to the present invention, FIG. 4 is a schematic sectional view of a radiation thermometer according to an embodiment of the present invention, and FIG. 5 is an illustration of the i\i area display means. A diagram showing an example,
FIG. 6 is an explanatory diagram of the relationship between the iFl area and the target cone corresponding to the index when using the area display means shown in FIG. 5, FIG. 7 is a diagram showing another example of the area display means, and FIG. FIG. 7 is an explanatory diagram of the relationship between the area corresponding to the index and the target cone when using the area display means shown in FIG. 7, and FIG. 9 is a diagram showing the case where there is only one index in the finder. 10... Temperature measurement optical system, 11... Condensing mirror (concentrator),
12...Temperature sensor, 20...Distance measurement system, 21...
Infrared LED, 22... Lens, 23... Light receiving lens, 24... Position sensor, 30... Finder system, 33... Focus plate, 40.41.50-53...
index.

Claims (1)

[Scope of Claims] 1. A temperature measurement optical system including a light condenser that collects emitted light from an object to be measured and a temperature measurement sensor consisting of a photoelectric conversion element in a fixed arrangement; A distance measuring means for measuring distance; and an area display means incorporated in a finder system for observing an object to be measured and displaying an area whose temperature is measured by the temperature measuring optical system according to the output of the distance measuring means. A radiation thermometer characterized by: 2. The distance measuring means includes a means for projecting a beam of light in a wavelength range different from that measured by the temperature sensor onto the object to be measured, and a means for condensing the reflected light to form an image on a predetermined surface. 2. The radiation thermometer according to claim 1, further comprising: a means for causing the image to be formed; and a position sensor located on the predetermined surface to detect the imaging position. 3. The area display means provides a plurality of indicators of different sizes in the finder, and according to the output of the distance measurement means,
2. The radiation thermometer according to claim 1, wherein the radiation thermometer is configured to indicate within which index the area whose temperature is being measured falls within. 4. A claim characterized in that indicating means for indicating within which index the area whose temperature is measured according to the output of the distance measuring means is provided in the finder separately from the index. 3. The radiation thermometer described in 3. 5. The radiation thermometer according to claim 1, wherein the area display means is configured to change the size of the indicator for displaying the area whose temperature is to be measured in accordance with the output of the distance measuring means. . 6. Arrange the temperature measuring optical system, the distance measuring means that optically measures the distance to the object to be measured, and the finder system incorporating the area display means so that their respective optical axes coincide. The radiation thermometer according to claim 1, characterized in that: