JPH07243916A - Radiation thermometer - Google Patents

Abstract

PURPOSE:To position a radiation thermometer at the measurement region easily, correctly, and quickly and improve its operability. CONSTITUTION:This radiation thermometer is constituted of a fitting section 1, an optical system section 2, a detection section 3 having a sensor section 33, and a finder section 4. The detection section 3 and the finder section 4 can be selectively fitted to or removed from the optical system section 2, and they have nearly the same optical axis as that of the optical system section 2. The optical system section 2 has a visual field frame 24 for setting the visual field wider than the measurement region near the image forming face of an objective optical system section 20 and the index for indicating the measurement region. The measurement region is made to coincide with the index while the finder section 4 is peeped, and the fastening separation lengths between the fitting section 1 and the optical system section 2 can be adjusted in the circumferential direction via screws at multiple positions of a flange 23 portion respectively. The detection section 3 has a shielding member regulating the incidence of the radiation energy from regions other than the measurement region in front of the sensor section 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation thermometer which receives radiant energy (infrared rays) radiated by a measuring object and remotely measures the temperature of the measuring object from the amount of received light.

[0002]

2. Description of the Related Art A radiation thermometer for remotely measuring the temperature of an object to be measured has been proposed which is equipped with a finder optical system for aligning the measuring position (Japanese Patent Laid-Open No. 62-62).
-106327). This radiation thermometer is a detection optical system in which a sensor is arranged on the optical axis of a Cassegrain type optical system consisting of a concave mirror and a convex mirror, behind which is a condenser lens, and an objective arranged on the optical axis. A mirror that is arranged behind the lens at an angle of 45 ° and forms another optical axis by branching the optical axis in the middle, and further, an index plate arranged at an image forming position via a pentaprism, and behind the index plate. And a viewfinder optical system including an eyepiece arranged. Then, the alignment is performed by adjusting the direction of the thermometer so that the center of the measurement area by the detection optical system matches the index position of the index plate of the finder optical system. The measurement area is generally set to a very small solid angle of about 0.3 ° to 2 ° in order to set the position at which the temperature should be measured reliably. Therefore, accurate alignment is required. By doing so, accurate temperature measurement for the measurement position can be ensured.

However, the above conventional radiation thermometer has the following problems. (1) Two optical axes, that is, the optical axis of the detection optical system and the optical axis of the finder optical system are required, which is disadvantageous in terms of space and cost. (2) Very fine adjustment work is separately required to match both optical axes. (3) When the radiation thermometer is fixedly installed and used, the finder is required only when positioning the thermometer when positioning the thermometer. Then, once the measurement area is set and the thermometer is fixed, no finder is required. Therefore, it is wasteful to have the finder optical system inside the thermometer. Considering the above (1) and (2), it is desirable that the optical axis passing through the detection optical system and the optical axis of the finder optical system are the same.

Therefore, in recent years, a radiation thermometer has been proposed in which the optical axis passing through the detection optical system and the optical axis of the finder optical system are the same (Japanese Utility Model Publication No. 5-26509). In this radiation thermometer, a connector receiver 21 having a small hole is attached to the rear of the condenser lens 20 at the focal position thereof, and the light beam condensed in the small hole is guided to the detection portion 4 at the rear portion thereof. The connector 31 for connecting the optical fiber 3 is detachably provided. Further, the connector receiver 21
In the rear part, the eyepiece device 6 is detachably provided on the same optical axis. According to this radiation thermometer,
The problems of (1) and (2) can be solved.

[0005]

However, since both optical axes are made the same, the following points become a new problem.
That is, in the radiation thermometer, generally, a light shielding member for limiting the light flux so that only the light flux from the measurement area is incident on the sensor is provided to ensure the measurement accuracy. In the latter radiation thermometer, the small hole on the connector 21 and the fiber 3 following the small hole play the role.

If the eyepiece device 6, that is, the finder is attached to such a thermometer in an exchangeable manner, the field of view of the finder is limited to the measurement area. That is, even if you look through the viewfinder,
Only a very narrow range of 0.3 ° to 2 ° can be seen. Since the purpose of the finder of the radiation thermometer is to set and check the measurement area, the viewfinder field covers a much wider range than the measurement area, and the index that indicates the measurement area is provided in the center of the finder field to measure. It is convenient to perform the position adjustment so as to match with the index, and by doing so, the quick and accurate position adjustment becomes possible. However, with the finder used in the latter thermometer, although the state inside the measurement area can be confirmed, the state outside the area, especially the surrounding area, cannot be confirmed at all, which makes it extremely inconvenient when performing position adjustment. Will be things.

The present invention has been made in view of the above,
Both the optical axis of the detector and the viewfinder that are selectively removable in the main housing are made the same, and the index is provided and the field of view of the viewfinder is wider than the measurement area to improve workability and usability when adjusting the measurement area. The object is to provide a better radiation thermometer.

[0008]

According to the present invention, a detector for receiving radiant energy and outputting an electric signal according to the radiant energy, a finder portion having an eyepiece optical system, and a radiant energy from an object to be measured are converged. And a main housing including a connecting portion that selectively and removably attaches the detection portion and the finder portion, the detection portion and the finder portion being substantially different from the main housing. It is configured to have the same optical axis, and in the main housing, a field frame for setting a field of view wider than the measurement area in the vicinity of the image plane of the objective optical system and the measurement area for showing the measurement area. The indicator is provided, and the detection unit is provided with a light blocking member for restricting the incidence of radiant energy from a region other than the measurement region on the front surface of the light receiving sensor (claim). 1).

Further, the main casing is further provided with an adjusting portion for adjusting the optical axis of the main casing so that the measurement area coincides with the index (claim 2).

[0010]

According to the first aspect of the invention, the optical axis of the detection section and the optical axis of the finder section are substantially coincident with each other, and the index is provided and the finder field is wider than the measurement area.

According to the second aspect of the present invention, the main housing is provided with the adjusting portion for adjusting the optical axis so that the measurement area coincides with the index, so that the finder image is attached with the finder portion attached. After adjusting the optical axis so that the measurement area coincides with the index while looking at it, if the detection unit is attached, the light receiving sensor held by the detection unit will accurately receive the light flux from the measurement area, that is, the radiant energy. .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall side sectional view showing an example of a radiation thermometer according to the present invention. The radiation thermometer comprises a mounting portion 1 as a main housing, an optical system portion 2, a detection portion 3 that can be selectively connected to the main housing, and a finder system 4.

The mounting portion 1 has a cylindrical shape, and a front side mounting structure portion 11 for mounting the radiation thermometer at a measurement location.
A rear mounting structure 12 for mounting the optical system unit 2 is formed. The front-side mounting structure portion 11 is adapted to be fittable to a rear end cylinder portion of a fixing member (not shown) arranged at a measurement location. By turning the mounting portion 1 by a required amount in the fitted state, an engagement concave portion 111a that engages with the fixing member is formed to prevent coming off. Alternatively, the inner peripheral surface may be screwed so as to be screwed with a screwing portion of a fixing member (not shown). The rear mounting structure 12 has an inner diameter that is the same as the outer diameter of the front end of the optical system 2, so that the optical system 2 can be fitted securely. The inner peripheral diameter of the inner peripheral diameter portion 121 on the depth side in the longitudinal direction is reduced, and the stepped portion 121a regulates the fitting length of the optical system portion 2. Also,
Inside the thickness of the rear end surface of the rear side mounting structure 12, female screw holes 13 having predetermined lengths at predetermined intervals along the circumferential direction thereof.
However, for example, as shown in FIG. 5A when the mounting portion 1 is viewed from the rear end side, a plurality of screws are screwed.

The optical system 2 has a cylindrical shape, and an objective lens 20, a transparent or light-attenuating protection filter 21 and a lens fixing member 22 for fixing these in a cylinder are provided on the front end side. A flange 23 for mounting with the mounting portion 1 is provided around the outer peripheral surface thereof. In addition, an index plate 24, which will be described later, and an index plate holder 25 having the fitting recess 251 for fixing the index plate 24, which will be described later, are provided on the rear end side.
And a fitting portion 26 is formed at the rear end.

The objective lens 20 has an image forming position at the index plate 2 described above.
4 or the position of a measurement area limiting plate 334 described later is used, or substantially the same. The protection filter 21 is for mechanical protection of the objective lens 20 and also for protection of an optical sensor described later against high-level incident light such as sunlight. The fitting portion 26 selectively attaches a detecting portion 3 and a finder portion 4 described later to the optical system portion 2 in a detachable manner.

The detecting section 3 has a cylindrical body, and a fitting recess 251 as a connecting section of the optical system section 2 and a fitting section 2 are provided at the front end thereof.
A sensor holder 30 and a large-diameter portion 31 which are fitted to the sensor 6 are provided, and a circuit portion 32 that outputs the sensor output as an electric signal is internally provided behind the sensor holder 30. Further, inside the cylinder of the sensor holder 30, the sensor unit 3 that receives radiant energy is received.
3 is provided. The finder section 4 has a tubular body,
The fitting concave portion 251, the cylindrical portion 40 fitted to the fitting portion 26, and the large diameter portion 41 are provided at the front end portion, and a finder optical system such as an objective lens 42 and an eyepiece lens 43 is provided behind the fitting concave portion 251. It is set up.

As will be described later, the detecting portion 3 is manufactured in advance so that the optical axis L3 coincides with the optical axis L1 of the optical system portion 2 with the sensor holder 30 fitted in the fitting recess 251. ing.

FIG. 2 is a side sectional view showing a state in which the finder section 4 is attached to the optical system section 2. In the optical system part 2, the lens fixing member 22 and the index plate holder 25 are both attached by screwing the threaded part on the outer peripheral surface thereof to the threaded part on the inner peripheral surface of the cylinder of the optical system part 2.

The lens fixing member 22 positions the objective lens 20 on the central axis of the optical system section 2 and at the same time the optical axis L thereof.
1 is matched with an index 241 (see FIG. 3) of the index plate 24, which will be described later. Further, the index plate holder 25 has a predetermined thickness, and a fitting recess 251 having a large diameter is bored from the rear side in the thickness direction by a required dimension, and a small diameter hole 252 connecting to the front side is bored. There is. The center of the hole 252 is substantially aligned with the optical axis L1 of the optical system unit 2 in a state where the index plate holder 25 is fixedly mounted on the optical system unit 2.

A thin index plate 24 is provided at the bottom of the fitting recess 251. The index plate 24 is shown in FIG.
As shown in (a), the whole is light-shielded, or is made of a light-shielding member, and a light hole 24a is formed in the central portion thereof so that light can be transmitted. As shown in the partially enlarged view of FIG. 3B, the light hole 24a has a notched shape in which fans are arranged to face each other. Further, the notch remaining portions 241 and 241 facing each other are formed such that both end portions thereof are separated from each other with a slight gap 124a. The notch remaining portions 241 and the gap 124a are used as indexes when the light flux from the measurement region is accurately focused on the gap 124a in the optical axis adjustment work by adjusting the tightened state of the screw 5.

As shown in FIG. 5B, the flange 23 is in the circumferential direction of each of the female screw holes 13 of the mounting portion 1.
At a position corresponding to the screwing position (Fig. 5 (a)), a through hole 231 having the same or slightly larger diameter as the female screw hole 13 is provided, while the screwing position of each female screw hole 13 ( In FIG. 5 (a), female screw holes 232 are formed in the longitudinal direction, preferably at the positions of the intermediate plane portions. Then, as shown in FIGS. 5C and 5D, the screw 51 is screwed into the female screw hole 232, and the tip of the screw 51 is brought into contact with the rear end surface of the mounting portion 1 so that the flange 23 and the mounting portion 1 are connected to each other. Are dimensionally regulated so that they are separated by a predetermined length,
The optical system part 2 is fixedly attached to the attachment part 1 by inserting the screw 5 into the female screw hole 13 and tightening it while rotating the screw 5 via.

As described above, by adopting the structure and fixing method shown in FIGS. 5A to 5D, the screwing amount of the screw 51 in each of them (the distance between the flange 23 and the mounting portion 1) and the screwing amount thereof can be obtained. By finely adjusting the tightening amount of the screws 5 on both sides corresponding to the above-mentioned distance, the mounting portion 1 and the optical system portion 2 can be adjusted.
It is also possible to make a fine adjustment so that the objective lens 20, that is, the optical axis L1 of the optical system section 2 coincides with the mounting angle relative to the center axis L0 of the mounting section 1.

The above construction is particularly effective when the radiation thermometer is arranged horizontally. On the other hand, when the radiation thermometer is arranged vertically upward, the flange 23 of the optical system portion 2 is located on the head side of the screw 5 due to its own weight, so that the female screw hole 232 and the screw 51 are provided. The configuration of is not particularly necessary. In the case of arranging vertically downward, the screw 5 may be fitted between the female screw hole 13 and the flange 23, and a dimension adjusting member such as a spring may be sandwiched.

FIG. 5 (e) shows another example of the structure of the flange 23 portion. The flange 23 'is, for example, 6 pieces in the circumferential direction of the flange 23' on the rear end surface of the optical system portion 2. Six through holes 231 'having the same or slightly larger diameter as the female screw holes 13' are bored in the longitudinal direction at positions corresponding to the positions of the female screw holes 13 'screwed at intervals. ing. The optical system part 2 is fixedly attached to the attachment part 1 by inserting the screw 5 into the female screw hole 13 'while turning the screw 5 through the through hole 231' and tightening it. The female screw holes 13 'and the through holes 231' are provided at a plurality of positions in the circumferential direction at regular intervals or predetermined intervals, that is, by having a plurality of tightening positions, if the tightening amount of the screw 5 in each is finely adjusted, Mounting part 1
With respect to the mounting angle between the optical system unit 2 and the optical system unit 2, that is, with respect to the central axis L0 of the mounting unit 1,
It is also possible to make fine adjustments so that the optical axes L1 of the above are matched.

If a spring or a washer (to be exact, C-shaped and both ends are axially displaced) packing material is interposed between the female screw hole 13 'and the through hole 231', the tightening dimension becomes large. As much as it can be taken, the difference from the tightening dimensions at other tightening positions can be increased, and the amount of adjustment of the optical axis can be increased to ensure reliable optical axis adjustment. Instead of the screw 5 for adjusting the optical axis, the mounting portion 1 and the optical system portion 2
It is also possible to provide a flange on both sides and fasten with bolts and nuts and springs, washers, etc. interposed at a plurality of locations.

Further, the optical axis adjustment for setting the measurement region is performed by adjusting the optical axes of the plurality of screws 5 while the finder section 4 is attached to the optical system 2 while observing both the index 124a and the measurement region. It is performed so as to match the two by appropriately adjusting the tightening amount.

Next, the finder portion 4 is a cylinder portion 40 at the front end portion.
And a large diameter portion 41 are formed, the outer diameter of the tubular portion 40 matches the inner diameter of the fitting recess 251, and the outer diameter of the large diameter portion 41 matches the inner diameter of the fitting portion 26. ing. Also, the fitting portion 2
A plurality of female screw holes 261 are screwed at predetermined intervals in the circumferential direction of 6, while a concave portion 411 is formed on the outer peripheral surface of the large diameter portion 41 at a position corresponding to the female screw holes 261. Has been done.

Then, with the large diameter portion 41 fitted in the fitting portion 26 and the female screw hole 261 and the recess 411 facing each other, the screw 6 is inserted into the female screw hole 261 and tightened, The finder section 4 is attached to the optical system section 2. It can be easily removed by removing the screw 6.

Further, the finder section 4 is provided with a finder optical system in which an objective lens 42 is provided in the front part inside the cylinder, and an eyepiece lens 43 and an eyepiece opening 44 are provided behind it. The finder optical system is configured so that the index plate 24 is in focus. Further, the finder optical system is manufactured in advance such that the optical axis L2 of the finder section 4 substantially coincides with the optical axis L1 of the optical system section 2 with the tubular section 40 fitted in the fitting recess 251 of the optical system section 2. Has been done. Therefore, by looking into the eyepiece opening 44, it is possible to visually confirm the measurement object existing in front of the axis L0. Further, both the measurement target and the index 241 can be viewed in focus during alignment. In this case, as will be described later, in the visible image, the light hole 24a is notched wider than the measurable measurement area of the sensor 330, so that the visual field of the eyepiece lens 43 through the light hole 24a is the measurement area. It is comparatively wider than the above, and this makes it possible to easily grasp the periphery of the measurement area.

4A and 4B are views showing another embodiment of the index plate, in which FIG. 4A shows the center having a transparent treatment, and FIG. 4B shows the index in the center of the transparent material. Is. The periphery of the index plate 24 'in FIG. 7A is light-shielded, and the central light hole 24a' which is not light-shielded has a required diameter, that is, a circular shape having a diameter such that even the periphery of the measurement area can be used as a field of view. The light hole 24 'itself serves as an index. The index plate 24 ″ of FIG. (B) is almost or entirely made of a transparent material such as glass,
An index 24a ″ having a square shape with a predetermined size is written in the center. In this example, the field of view is the index 24a.
Since it is not limited to the shape of "a", it can be widely used.
In addition, all of these modifications can be manufactured easily and the cost can be reduced.

In FIGS. 4A and 4B, the shape as the central index is not limited to the circle or the square shown in FIG. 3, and the required field of view can be secured and the light for setting the measurement area can be secured. As long as the axis can be easily adjusted, various appropriate shapes such as a rectangle, a hexagon, and an ellipse can be adopted in consideration of the correspondence with the measurement target.

FIG. 6 is a side sectional view showing a state in which the detecting section 3 is attached to the optical system section 2, and FIG. 7 is an optical system section 2 and the detecting section 3.
It is a partially enlarged view of the coupling part with.

A recess 311 is formed on the outer peripheral surface of the large diameter portion 31 at a position corresponding to the female screw hole 261.

Then, the large-diameter portion 31 is fitted into the fitting portion 26, and the screw 6 is inserted and tightened in the female screw hole 261 with the female screw hole 261 and the recess 311 facing each other. The detection unit 3 is attached to the optical system unit 2 and the finder unit 4
It is designed to be installed in exactly the same posture as in the case of.
It can be easily removed by removing the screw 6.

The sensor portion 33 is provided with a support plate 331 for the light receiving sensor 330, and the support plate 331 is circumferentially provided with a sensor stopper 332 having a threaded portion formed on its peripheral surface.
The sensor holder 30 can be screwed onto a threaded portion 301 on the inner peripheral surface thereof. The recessed groove portion 302 formed on the inner peripheral portion of the sensor holder 30 is for escape against the contact with the sensor holder 331.

The sensor 330 has, for example, a disk shape having a head light-receiving surface, and is, for example, a silicon photodiode or the like which receives infrared rays in the vicinity of 1 μm without an absorption band.
The circuit unit 32 converts the level signal according to the amount of received light into an electric signal.
Is output to. This sensor 330 is a support plate 33.
The sensor 330 is fixed to the front surface of the sensor 330, and on the other hand, through the holes 331a formed at two predetermined positions of the support plate 331.
The output terminal 330a of the above is led to the circuit section 32. The circuit section 32 is for generating a linear level signal with respect to the temperature by amplifying the sensor output and further performing a predetermined calculation process, that is, a process in which the light receiving characteristic of the sensor 330 is added. A more accurate level signal can be generated by taking into consideration the emissivity of the object, the light transmittance of the object existing between the measurement object and the light receiving surface of the sensor 330, and the like.

The circuit portion 32 is movably supported at a predetermined position inside the cylinder by a rib (not shown) formed inside the detection portion 3 or another supporting member. Further, the circuit unit 32 may perform necessary processing, convert into analog or digital and output as an electric signal, and lead it to a thermometer main body side (not shown) to calculate and display temperature data there. Also, the temperature data is calculated in the circuit unit 32, and the calculated temperature data is displayed on the display unit at an appropriate external location.
Alternatively, a display unit may be provided at a proper place on the outer surface of the detection unit 3 and the display may be performed directly there.

A spectral sensitivity correction filter 333 having a predetermined thickness is provided on the light receiving surface which is the front surface of the sensor 330. The spectral sensitivity correction filter 333 is for limiting the measurement wavelength to the wavelength with the least disturbance.

The sensor holder 30 is a front portion of the spectral sensitivity correction filter 333, and a hole portion 303 having a predetermined diameter is formed at the center of the sensor holder 30. Large diameter cylindrical recess 3
04 are formed. A thin plate-shaped measurement region limiting plate 334 is disposed on the front surface of the recess 304. Further, the center of the measurement area limiting plate 334, that is, the sensor holder 30.
A circular small hole 334a is formed at a position corresponding to the center of the circle. This small hole 334a is relatively small compared to the diameter of the light hole 24a, and is for passing only a part of the light beam in the central portion of the light beam that has passed through the light hole 24a. Therefore, only the light flux from the measurement area in the range regulated by the small hole 334a is guided to the light receiving surface of the sensor 330.

A back cover 34 for shading is provided at the rear of the detecting section 3 to prevent stray light from entering the inside of the cylinder and ensure measurement accuracy.

In the structure of the detection unit 3, the small hole 334a of the measurement area limiting plate 334 is aligned with the axial center of the sensor holder 30 fitted in the fitting recess 25. Therefore, after the viewfinder portion 2 is seen through the eyepiece opening 44 and the measurement area is accurately aligned with the index center or the specific position of the index by finely adjusting the screws 5 and 51, the viewfinder portion 4 is moved to the optical system portion 2. When the detector 3 is detached and the detector 3 is attached, the measurement region exactly coincides with the position set by the fine unit 4, and the adjustment work is unnecessary. In addition, considering that the optical axis adjustment work is performed only at the time of the first attachment, the measurement area does not shift even if the detection unit 3 is subsequently attached or detached, so that the optical axis adjustment is forced each time it is detached. There is no complication.

In this embodiment, the main housing is provided with the adjusting portion, and the relative position (angle) of the main housing with respect to the mounting portion.
Although the measurement area is set by adjusting, the adjustment unit does not necessarily have to be provided in the main housing. For example, the adjustment unit may be provided in the mounting unit and the relative position (angle) of the mounting unit with respect to the measurement target may be adjusted. In this case, the radiation thermometer, which is the main body of the apparatus, does not need to be provided with an adjusting unit.

[0043]

As described above, according to the present invention, the detection unit capable of detecting only the radiant energy from the measurement region of the measurement object and the finder unit for aligning the measurement region can be selectively attached and detached. The main frame has a substantially same optical axis, and the main frame has a field frame for setting a field of view larger than the measurement region in the vicinity of the image plane of the objective optical system and the above-mentioned measurement. The indicator for indicating the area is provided, and further, since the detection section is provided with a light shielding member for limiting the incidence of the radiant energy from the area other than the measurement area, the alignment of the measurement area is performed. It can be done easily and quickly while looking at the index. Also, since the viewfinder field is wider than the measurement area, you can also check the periphery of the measurement area.
Positioning work by the adjusting unit can be performed extremely easily and accurately. Furthermore, since the detection unit and the finder unit can be selectively attached to and detached from the main housing, it is not necessary to perform the position adjustment each time the detector unit is attached or detached after the finder unit is aligned, which is convenient.

[Brief description of drawings]

FIG. 1 is an overall side sectional view showing an example of a radiation thermometer according to the present invention.

FIG. 2 is a side sectional view showing a state in which a finder section is attached to an optical system section.

3A and 3B are diagrams showing an example of the configuration of an index plate, FIG. 3A is a plan view, and FIG. 3B is an enlarged view of the central portion of FIG.

4A and 4B are views showing another embodiment of the index plate, in which FIG. 4A shows a transparent material in the center, and FIG. 4B shows an index in the center of the transparent material.

FIG. 5 is a diagram for explaining a structure and a mounting operation of a flange portion for mounting the optical system portion on the mounting portion,
(A) to (d) relate to the present embodiment, (a) is a view of the mounting portion from the rear end side, (b) is a view of the flange from the front end side, (c), (d) Mounting Partial side sectional view for explaining the operation, (e) is a view of the flange for explaining another structural example as seen from the tip side.

FIG. 6 is a side sectional view showing a state in which a detection unit is attached to the optical system unit.

FIG. 7 is a partially enlarged view of a coupling portion between an optical system and a detection unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mounting part 11 Front mounting structure part 12 Rear mounting structure part 13, 13 'Female screw hole (adjusting part) 2 Optical system 20 Objective lens 21 Protection filter 22 Lens fixing member 23, 23' Flange (adjusting part) 231,231 ′ Through hole (adjustment part) 232 Female screw hole (adjustment part) 24, 24 ′, 24 ″ Index plate 24a, 24a ′ Optical hole 241, 24a ″ Index 25 Index plate holder 251 Fitting recess (connecting part) 252 Small diameter Hole 26 Fitting part (connecting part) 261 Female screw hole 3 Detection part 30 Sensor holder 303 Hole part 31 Large diameter part 311,411 Recess 32 Circuit part 33 Sensor part 330 Sensor 331 Support plate 332 Sensor stopper 333 Spectral sensitivity correction filter 333 334 Measurement area limiting plate 334a Small hole 34 Back cover 4 Finder section 40 Cylindrical section 41 Large-diameter section 42 vs. Burrlet Lens 43 Eyepiece 44 Eyepiece aperture 5 Screw (adjustment part) 6 Screw L0 Central axis of mounting part L1 Optical axis of optical system L2 Optical axis of finder part L3 Optical axis of detecting part

Claims (2)

[Claims] 1. A detection unit for receiving radiant energy and outputting an electric signal according to the radiant energy, a finder unit having an eyepiece optical system, and an objective optical system for converging the radiant energy from the object to be measured. And a main housing having a connecting portion for selectively and removably attaching the detection portion and the finder portion, wherein the detection portion and the finder portion have substantially the same optical axis with respect to the main housing. The main casing is provided with a visual field frame for setting a visual field wider than the measurement region and an index for indicating the measurement region in the vicinity of the image plane of the objective optical system, A radiation thermometer, wherein the detection unit is provided with a light blocking member for restricting incidence of radiant energy from a region other than the measurement region on the front surface of the light receiving sensor. 2. The main housing is further provided with an adjusting section for adjusting an optical axis of the main housing so that a measurement region coincides with the index. Radiation thermometer.