JPH11197117A - Radiation thermometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a measurement error due to the temperature change of a probe inserted to the external auditory meatus or the like and to accurately detect a temperature in to a radiation thermometer for measuring the temperature of the eardrum without contact. SOLUTION: This radiation thermometer is composed of a signal processing means 22 for computing the output of a light receiving part 18 for receiving only infrared rays directly radiated from the eardrum and the vicinity to the temperature and a reporting mean 23 for reporting the temperature of a computed result. Since the influence of heat radiation from parts other than the eardrum and the vicinity is not received, the temperature change of the probe 2 is not turned to a measurement error factor and the temperature is accurately detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation thermometer for measuring the body temperature of a living body by detecting the amount of infrared radiation radiated from an ear canal.

[0002]

2. Description of the Related Art Conventionally, this kind of radiation thermometer is disclosed in
Nos. 6,385,851, JP-B-8-16629, and JP-A-9-105668 were common. FIG. 8 shows a radiation thermometer described in Japanese Patent Publication No. 6-63851. Reference numeral 1 denotes a cylindrical waveguide whose inner and outer surfaces are smooth and mirror-like. Reference numeral 2 denotes a removable protective cover, and reference numeral 3 denotes an infrared sensor. This operation will be described. When inserted into the external auditory meatus 4 with the protective cover 2 attached, infrared rays emitted from the eardrum 5 and its vicinity enter the infrared sensor 3 while reflecting on the inner surface of the waveguide 1. The inner and outer surfaces of the waveguide 1 are
Is processed into a smooth mirror surface so that the infrared sensor 3 does not receive the heat radiation.

FIG. 9 shows a configuration of a radiation thermometer described in Japanese Patent Publication No. Hei 8-16629. FIG. 9 is a configuration diagram of a probe to be inserted into the ear canal, 6 is an opening at the tip of the probe, 7 is a lens, and 8 is an aperture for further narrowing the radiated light collected by the lens 7. Reference numeral 9 denotes a thermistor for measuring the temperature of the infrared sensor 3, which is embedded in the isothermal block 10. Reference numeral 11 denotes a thermal insulator (thin cap) attached to the tip of the probe, which has an air gap 12 between itself and the outer surface of the probe. Reference numeral 13 denotes a thermistor for measuring the temperature at the tip of the probe, and solid line 14 denotes radiated infrared light incident on the infrared sensor 3 from the back of the ear canal. Dotted line 15
Is emitted from the inner surface of the probe tip and the infrared sensor 3
Shows the infrared light incident on. This operation will be described.
When the probe is inserted into the ear canal, infrared rays emitted from the vicinity of the eardrum are condensed by the lens 7 and incident on the infrared sensor 3 as shown by a dotted line 15. However, at this time, the temperature at the tip of the probe rises due to heat conduction from the ear canal.
Since this causes a measurement error, a thin cap 11 made of a thermal insulator is attached to the tip of the probe, and the probe is insulated by an air gap 12.
The heat conduction from the ear canal to the tip of the probe hardly occurs. In this publication, when the temperature at the tip of the probe rises, as shown by a dotted line 15, thermal radiation from the inner surface of the tip of the probe is incident on the infrared sensor 3 via the lens 7, so that the measurement accuracy is further improved. As a means for improving, a thermistor 13 is attached to the tip of the probe,
Even if the temperature at the tip of the probe rises, the temperature is corrected by the thermistor 13 to improve the measurement accuracy of the body temperature. FIG. 10 shows a configuration of an infrared sensor described in Japanese Patent Application Laid-Open No. 9-105668. An infrared sensor 3 and a lens 7 are provided.
Is arranged on the lens 7 side of the focal point 16.

[0004]

However, in the configuration of the radiation thermometer disclosed in Japanese Patent Publication No. 6-63851, the infrared radiation emitted from the vicinity of the eardrum 5 shown in FIG. In this configuration, the light is incident on the sensor 3. In this case, the viewing angle of the infrared sensor is as wide as about 180 degrees. That is, the infrared light entering the waveguide 1 at all angles repeatedly reflects on the inner surface of the waveguide 1 and enters the infrared sensor 3. This means that not only the infrared radiation radiated from the eardrum 5 but also the radiated infrared radiation of the entire external auditory canal 4 is made incident on the infrared sensor, so that there is a problem that an accurate eardrum temperature cannot be detected. Furthermore, when heat is transferred from the ear canal to the waveguide when inserted into the ear, the infrared sensor receives thermal radiation infrared rays from the waveguide, which increases the measured body temperature. Become. For this purpose, the inner and outer surfaces of the waveguide are processed into a smooth mirror surface to prevent heat radiation.
Mirror finishing with a reflectance of 1 and no thermal radiation is impossible.
Further, as shown in FIG. 11, even if a mirror surface processing with an emissivity close to zero is performed, heat radiation in the vertical direction from the mirror surface can be suppressed, but heat radiation in the horizontal direction cannot be suppressed. FIG.
Reference numeral 1 denotes a directional emissivity characteristic of aluminum, for example, where Φ = 0 ° in the vertical direction with respect to the mirror surface and 90 ° in the horizontal direction. The emissivity. Therefore, the infrared sensor receives heat radiation infrared rays from the inner surface of the waveguide, and there is a problem that a measurement error is generated by the amount of the received infrared rays.

In the configuration of the radiation thermometer described in Japanese Patent Publication No. Hei 8-16629, although the infrared ray radiated from the vicinity of the eardrum is condensed by the lens 7 and made incident on the infrared sensor 3, the probe Since heat radiation infrared rays from the inner surface of the tip also enter the infrared sensor, it is necessary to correct the temperature by attaching a heat insulating thin cap to the tip of the probe or by attaching a thermistor for measuring the temperature of the tip of the probe. However, absolute insulation of the probe tip is impossible, and if the probe is repeatedly inserted into the ear canal and measured, the temperature of the probe tip rises, and the measured body temperature rises with an error. In addition, the thermistor itself has variations such as thermal responsiveness and B constant, so that there is a problem that a measurement error is caused by the variation. further,
The fact that the probe is affected by the heat radiation from the inner surface of the probe tip means that the infrared sensor does not have a configuration in which the infrared sensor only looks at the eardrum and its vicinity in a spot-like manner. Therefore, there was a problem that an accurate eardrum temperature could not be detected.

In the configuration of the infrared sensor described in Japanese Patent Application Laid-Open No. 9-63851, the installation position of the infrared sensor is set closer to the lens than the focal point of the lens in order to widen the field of view of the infrared sensor. When a radiation thermometer is configured with this configuration, it is difficult to detect only infrared radiation from the eardrum and its vicinity in a spot-like manner.When a probe is mounted, heat radiation from the inner surface of the probe is detected by infrared radiation. It is easily conceivable that the sensor receives light.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a light receiving section for receiving only infrared rays directly radiated from the eardrum and its vicinity, and a signal processing for calculating an output of the light receiving section into a temperature. And an informing means for informing the output of the signal processing means, and is configured not to be affected by heat radiation from portions other than the eardrum and its vicinity.

According to the above invention, the temperature of the output from the light receiving section that receives only the infrared radiation directly radiated from the eardrum and its vicinity is calculated by the signal processing means and is notified by the notification means. The temperature of the eardrum can be accurately detected without being affected by the heat radiation of the horn.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A radiation thermometer according to a first aspect of the present invention includes a light receiving section for receiving only infrared rays directly radiated from the eardrum and its vicinity, and a signal processing means for calculating an output of the light receiving section into a temperature. And an informing means for informing the output of the signal processing means, so as not to be affected by heat radiation from areas other than the eardrum and its vicinity.

Then, the output from the light receiving section which receives only the infrared radiation directly radiated from the eardrum and its vicinity is calculated into the temperature by the signal processing means and is notified by the notification means, so that the heat radiation from the area other than the eardrum and its vicinity is notified. An accurate eardrum temperature can be detected without being affected.

According to a second aspect of the present invention, there is provided a radiation thermometer which is inserted into an external auditory canal, fixes a direction of the eardrum, and allows infrared rays emitted from the eardrum and its vicinity to pass therethrough;
A light receiving unit that receives the infrared light that has passed through the probe, a signal processing unit that calculates the output of the light receiving unit to a temperature, and a notifying unit that notifies the output of the signal processing unit, wherein the light receiving unit includes at least a probe. A light-collecting element that collects the infrared light that has passed through, and an infrared light-receiving element that receives the infrared light that has been collected by the light-collecting element, and separates the infrared light-receiving element backward from the focal position of the light-collecting element. The light receiving area is limited by installing the light receiving device.

The light receiving section receives only infrared rays radiated from the eardrum and the vicinity thereof and passed through the probe, the signal processing means calculates an output from the light receiving section to a temperature, and the notifying means notifies the temperature of the calculation result. . The infrared light condensed by the light-collecting element enters the infrared light-receiving element of the light-receiving section, and the infrared light-receiving element is located away from the focal position of the light-collecting element, so that it is collected from the inner wall of the probe. Infrared rays incident on the element can be advanced to positions other than the infrared light receiving element,
The light receiving area can be limited. As a result, it is possible to spot-detect only the radiation emitted from the eardrum and its vicinity and passed through the probe.

According to a third aspect of the present invention, there is provided a radiation thermometer, wherein the infrared light receiving element is in contact with the inner wall of the probe on the same side as the edge of the light collecting element with respect to the optical axis from the edge of the light collecting element. An image of the virtual tip point by the light-collecting element passing through the edge of the light-collecting element on the same side as the virtual tip point with respect to the optical axis from a virtual tip point where the drawn straight line intersects the surface of the tip of the probe. It is configured to be installed in a region farther from the light-collecting element than an intersection of an optical path reaching the point and the optical axis and closer to the light-collecting element than an image point of the virtual tip point by the light-collecting element. .

The infrared light received by the light-collecting element is incident on the infrared light-receiving element, and the infrared light-receiving element passes through the edge of the light-collecting element on the same side as the virtual tip point and is condensed by the light-collecting element. The probe inner wall is installed in a region farther from the light-collecting element than the intersection of the optical path and the optical axis reaching the image point of the virtual tip point and closer to the light-collecting element than the image point of the virtual tip point by the light collecting element. Infrared light incident on the light-collecting element from the light-receiving element can travel to a position other than the infrared light receiving element, and the light receiving area can be limited. As a result, it is possible to spot-detect only the radiation emitted from the eardrum and its vicinity and passed through the probe. Further, the radiation thermometer according to claim 4 of the present invention is such that the infrared light receiving element is drawn from the edge of the light collecting element so as to be in contact with the inner wall of the probe on the same side as the edge of the light collecting element with respect to the optical axis. Passes through the edge of the light-collecting element on the same side as the virtual tip point with respect to the optical axis from the virtual tip point that intersects the tip surface of the probe, and reaches the image point of the virtual tip point by the light-collecting element A configuration is provided in a triangle in the meridional plane of the light-collecting element, which is formed by an intersection point of the optical path and the optical axis to be formed and two image points of the virtual tip point by the light-collecting element. It is what it was.

The infrared light condensed by the light condensing element is incident on the infrared light receiving element, and the infrared light receiving element passes through the edge of the light condensing element on the same side as the imaginary tip point and is condensed by the light condensing element. Being set in a triangle in the meridional plane of the light-collecting element formed by the intersection of the optical path and the optical axis reaching the image point of the virtual point and the two image points of the virtual point by the light-collecting element Thus, the infrared light incident on the light collecting element from the inner wall of the probe can be advanced to a position other than the infrared light receiving element, and the light receiving area can be limited. As a result, it is possible to spot-detect only the radiation emitted from the eardrum and its vicinity and passed through the probe.

In the radiation thermometer according to a fifth aspect of the present invention, the infrared light receiving element is arranged so that the infrared light receiving element is in contact with the inner wall of the probe on the same side as the edge of the light collecting element with respect to the optical axis from the edge of the light collecting element. In this configuration, the drawn straight line is located in a region farther from the light-collecting element than an image point formed by the light-collecting element at a virtual tip point intersecting the front end surface of the probe.

The infrared light condensed by the light-collecting element enters the infrared light-receiving element, and the infrared light-receiving element is moved from the edge of the light-condensing element to the optical axis with respect to the optical axis. By placing the straight line drawn so as to be in contact with the inner wall of the probe on the side farther from the light-collecting element than the image point of the light-collecting element at the virtual tip point intersecting with the surface of the tip of the probe, Infrared rays incident on the light-collecting element can be made to travel to positions other than the infrared light-receiving element, and the light-receiving area can be limited. As a result, it is possible to spot-detect only the radiation emitted from the eardrum and its vicinity and passed through the probe.

Further, in the radiation thermometer according to claim 6 of the present invention, the infrared light receiving element is arranged so that the infrared light receiving element is in contact with the inner wall of the probe on the same side as the edge of the light collecting element with respect to the optical axis from the edge of the light collecting element. The drawn straight line passes through the edge of the light-collecting element opposite to the virtual tip point across the optical axis from a virtual tip point that intersects the tip surface of the probe, and The light-collecting device is arranged in a region between two optical paths in a meridional plane reaching the image point.

The infrared light received by the light-collecting element is incident on the infrared light-receiving element, and the infrared light-receiving element is positioned at the same distance from the edge of the light-collecting element to the optical axis as the edge of the light-collecting element. A straight line drawn so as to be in contact with the inner wall of the side probe passes through the edge of the light-collecting element opposite to the virtual tip point across the optical axis from a virtual tip point intersecting the surface of the tip of the probe. The infrared light incident on the light-collecting element from the inner wall of the probe is placed in the area between the two optical paths in the meridional plane of the light-collecting element reaching the image point of the virtual tip point by the light-collecting element. The light can be moved to a position other than the light receiving element, and the light receiving area can be limited. As a result, it is possible to spot-detect only the radiation emitted from the eardrum and its vicinity and passed through the probe.

According to a seventh aspect of the present invention, in the radiation thermometer, the infrared light receiving element includes a focal length f of the light collecting element, a radius rS of the infrared light receiving element, and an optical axis extending from an edge of the light collecting element. The distance rα between a virtual tip point and an optical axis where a straight line drawn so as to be in contact with the inner wall of the probe on the same side as the edge of the light-collecting element intersects the surface of the probe tip, The distance Lα from the light-collecting element and the radius r3 of the light-collecting element
Using,

[0021]

(Equation 3)

The light source is set farther from the light collecting element than the focal point of the light collecting element by L3 given by

The infrared light condensed by the light condensing element is incident on the infrared light receiving element. The infrared light receiving element has a focal length f of the light condensing element, a radius rS of the infrared light receiving element, and a virtual tip. Using the distance rα between the point and the optical axis, the distance Lα between the virtual tip point and the light-collecting element, and the radius r3 of the light-collecting element, the light is condensed by L3 given by the above equation from the focal point of the light-collecting element. By installing the device far from the device, the infrared light incident on the light collecting device from the inner wall of the probe can travel to a position other than the infrared light receiving device, and the light receiving area can be limited. As a result, it is possible to spot-detect only the radiation emitted from the eardrum and its vicinity and passed through the probe.

In the radiation thermometer according to the eighth aspect of the present invention, the infrared light receiving element may include a focal length f of the light-collecting element, a radius rS of the infrared light-receiving element, and an optical axis extending from the edge of the light-collecting element. A distance rα between an optical axis and a virtual tip point at which a straight line drawn so as to be in contact with the inner wall of the probe on the same side as the edge of the light-collecting element intersects the surface of the tip of the probe; Using the distance Lα between the light-collecting element and the radius r3 of the light-collecting element,

[0025]

(Equation 4)

In this configuration, L3 is set farther from the light-collecting element than the focal point of the light-collecting element.

The infrared light condensed by the light-collecting element enters the infrared light-receiving element. The infrared light-receiving element has a focal length f of the light-collecting element, a radius rS of the infrared light-receiving element, and a virtual tip. Using the distance rα between the point and the optical axis, the distance Lα between the virtual tip point and the light-collecting element, and the radius r3 of the light-collecting element, the focal point of the light-collecting element is shifted by L3 represented by the above equation. By arranging the light-receiving element far from the light-collecting element, the infrared light incident on the light-collecting element from the inner wall of the probe can travel to a position other than the infrared light-receiving element, and the light-receiving area can be limited. As a result, it is possible to spot-detect only the radiation emitted from the eardrum and its vicinity and passed through the probe.

In the radiation thermometer according to a ninth aspect of the present invention, the light-collecting element is constituted by a refractive lens.

Then, the condensed infrared rays enter the infrared light receiving element by the refraction lens. Claim 1 of the present invention
In the radiation thermometer according to 0, the light-collecting element is constituted by a transmission type diffraction lens.

Then, the collected infrared rays enter the infrared light receiving element by the transmission type diffraction lens.

Further, in the radiation thermometer according to claim 11 of the present invention, the light-collecting element is constituted by a light-collecting mirror.

Then, the collected infrared light is incident on the infrared light receiving element by the light collecting mirror. Claim 1 of the present invention
In the radiation thermometer according to 2, the light-collecting element is constituted by a reflective diffraction lens.

The reflected infrared rays are incident on the infrared light receiving element by the reflection type diffraction lens.

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of the radiation thermometer of the present invention. FIG. 2 is a configuration diagram of the light receiving unit and the probe. In FIG. 1, reference numeral 2 denotes a probe which is inserted into the ear canal at the time of measuring the body temperature and has a shape which is thinner toward the distal end toward the eardrum, and the distal end portion 6 is open or an infrared ray passes therethrough for the purpose of dust protection. It has a film of material. The probe 2 is mounted on a main body 17, and the main body 17 incorporates a light receiving section 18 and the like.
The light receiving section 18 is composed of a pyroelectric infrared light receiving element 3 and a light condensing element 7, and only infrared light directly radiated from the eardrum passing through the probe 2 and its vicinity enters the infrared light receiving element 3. Reference numeral 19 denotes a chopper, at least the surface of which is made of a material that reflects infrared light such as a metal, and is driven by a motor 20 to intermittently intercept and intercept infrared light emitted from the eardrum and its vicinity from the eardrum. The pyroelectric infrared light receiving element 3 generates an electrical output correlated with a change in the amount of incident infrared light. Here, since the surface of the chopper 19 is made of a material that reflects infrared light, the infrared light emitted by the infrared light receiving element 3 itself is reflected and enters the infrared light receiving element 3 during light shielding. Accordingly, the infrared light radiated from the eardrum and its vicinity and the infrared light radiated by the infrared light-receiving element 3 are alternately incident on the infrared light-receiving element 3 by the operation of the chopper 19, so that the infrared light-receiving element 3 has the eardrum temperature and the red An electric output having a correlation with the temperature difference from the temperature of the external light receiving element 3 itself is generated.

A temperature sensor 21 for detecting the temperature of the infrared light receiving element 3 is, for example, a generally known thermistor. 22 is a signal processing means for calculating the temperature of the infrared light receiving element 3 from the output of the thermistor 21, calculating the temperature difference between the infrared light receiving element 3 and the eardrum from the output of the infrared light receiving element 3, and adding them. Can be used to calculate the temperature of the eardrum. Reference numeral 23 denotes a notification unit, which displays the temperature of the eardrum calculated by the signal processing unit, for example, by numerical display. The notification means 23 may display a temperature in degrees Celsius, a temperature in degrees Fahrenheit, a bar graph, or an audio notification. Further, these may be switched.

Here, since the light receiving section 10 receives only infrared rays emitted from the eardrum and the vicinity thereof and passed through the probe 2, the light receiving section 10 is not affected by the temperature fluctuation of the probe 2. Therefore, no waveguide is required, and there is no need to measure the temperature of the probe 2, and accurate body temperature measurement is possible.

The structure of the light receiving section 18 will be described with reference to FIG.
In FIG. 2, reference numeral 7 denotes a refracting lens which is a light collecting element, 3 denotes an infrared light receiving element, and 24 denotes a housing. A and A 'are intersections of a straight line drawn from the edge of the refractive lens 7 so as to be in contact with the inner wall of the probe 2 on the same side as the edge, and the surface of the tip of the probe 2;
In the case of a linear probe as shown in FIG. 2, this point is located on the inner wall of the distal end of the probe 2. B is a point on the inner wall of the probe 2, that is, a point in a region where light is not desired to be received, F is a focal point of the refraction lens 7, FA is an image point of A by the refraction lens 7, and FA '.
Is the image point of A 'by the refraction lens 7, and FB is the refraction lens 7
Is the image point of B, K1A is the optical path of light (marginal ray) traveling from A to the FA through the edge of the refractive lens 7 on the same side with respect to the optical axis, and K2A travels from A in parallel with the optical axis. The optical path of light passing through the focal point F and reaching the FA, K3A is A
K4A is an optical path of light passing through the center of the refraction lens 7 and arriving at the FA, and K4A is light (marginal ray) passing from A through the edge of the refraction lens 7 on the opposite side of the optical axis and reaching the FA.
Is the optical path. Similarly, K1A 'is an optical path of light (marginal ray) traveling from A' to the FA 'through the edge of the refractive lens 7 on the same side with respect to the optical axis, and K2A' is parallel to the optical axis from A '. K3A 'is an optical path of light that travels through the focal point F and reaches FA', K3A 'is an optical path of light that reaches FA' through the center of the refraction lens 7 from A ', and K4A' is an optical axis from A '. After passing through the edge of the refractive lens 7 on the opposite side
The optical path of light (marginal ray) reaching A ', K3B is the optical path of light passing from B through the center of the refraction lens 7 and reaching FB, and FX is the intersection of the optical paths K1A and K1A'.

An optical system is designed so that the infrared light receiving element 3 receives only infrared light emitted from the eardrum and its vicinity and passing through the probe 2.

The infrared light receiving element 3 is attached to the housing 24 so that the infrared light receiving element 3 does not receive infrared light that does not pass through the refractive lens 7. The following design is performed after a configuration is adopted in which only infrared light that has passed through the refraction lens 7 is received.

The light radiated from A is transmitted through optical paths K1A and K2.
A reaches the image point FA of A through A, K3A, K4A, and the like. As is well known in geometrical optics, the image point FA of A is formed on the opposite side of A with respect to the optical axis. As shown in FIG. 2, light passing through the optical path K2A passes through the refraction lens 7, crosses the optical axis at F, and reaches the FA while leaving the optical axis. Similarly, the light passing through the optical path K1A passes through the refraction lens 7, crosses the optical axis, and reaches the FA away from the optical axis. The light passing through the optical path K3A crosses the optical axis by the refraction lens 7 and then reaches the FA away from the optical axis. Optical path K4
The light passing through A crosses the optical axis, passes through the refractive lens 7,
After passing through the refractive lens 7, the light reaches the FA without crossing the optical axis. As described above, there is a region where the light radiated from A does not pass at a position farther from the refractive lens 7 than the point FX where the optical path K1A intersects the optical axis and closer to the refractive lens 7 than FA. This area is FX, FA and F
A 'is inside the triangle formed. By installing the infrared light receiving element 3 inside this triangle, a light receiving unit that does not receive light emitted from A and A ′ can be obtained.

It is well known that point B in the region of the inner wall of the probe 2 that does not want to receive light is farther from the optical axis than A, so that the image point FB of B by the refracting lens 7 is farther from the optical axis than FA. is there. Therefore, if the infrared light receiving element 3 is installed inside the triangle formed by the FX, FA and FA 'so as not to receive the infrared light radiated from A and A', the infrared light from B is automatically transmitted. The configuration does not receive light.

As described above, by disposing the infrared light receiving element 3 inside the triangle formed by the FX, FA and FA ', the area to receive light near the optical axis, that is, the eardrum passing through the probe 2 and its vicinity A light receiving portion that receives only infrared rays radiated from the light source is obtained.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a configuration diagram showing a light receiving unit and a probe of a radiation thermometer according to a second embodiment of the present invention. In FIG. 3, 7 is a refractive lens, 3 is an infrared light receiving element, and 24 is a housing. A and A 'are the intersections of a straight line drawn from the edge of the refractive lens 7 so as to be in contact with the inner wall of the probe 2 and the surface of the tip of the probe 2. If the probe is linear as shown in FIG. It is a point located on the inner wall. B is a point on the inner wall of the probe 2, that is, a point in an area where light is not desired to be received, F is a focal point of the refractive lens 7, FA is an image point of A by the refractive lens 7, FA 'is an image point of A' by the refractive lens 7, FB is the image point of B by the refraction lens 7, K1
A is an optical path of light (marginal ray) which travels from A to the FA through the edge of the refractive lens 7 on the same side with respect to the optical axis, and K
2A travels from A in parallel with the optical axis,
K3A is the optical path of the light from A passing through the center of the refraction lens 7 to the FA, and K4A is the FA from the A passing through the edge of the refraction lens 7 on the opposite side with respect to the optical axis.
K1A 'is the optical path of the light (marginal ray) that travels from A' to the FA 'through the edge of the refractive lens 7 on the same side with respect to the optical axis.
2A 'is an optical path of light that travels from A' in parallel with the optical axis and passes through the focal point F to reach FA ', and K3A' is a light path of light that reaches FA 'through the center of the refractive lens 7 from A'. Light path, K
4A 'is an optical path of light (marginal ray) passing through the edge of the refraction lens 7 on the opposite side of A' from the A 'and arriving at FA', and K3B is passing F through the center of the refraction lens 7 from B.
K4B is an optical path of light reaching B, K4B is an optical path of light (marginal ray) passing through the edge of the refraction lens 7 on the opposite side with respect to the optical axis and reaching the FB, and FX is an optical path K1A and an optical path K.
The intersection of 1A ', FY is the intersection of the optical path K4A and the optical path K4A'.

An optical system is designed so that only the infrared rays emitted from the eardrum and its vicinity and passing through the probe 2 are received by the infrared receiving element 3.

The infrared light receiving element 3 is mounted on the housing 24 so that infrared light not passing through the refractive lens 7 is not received by the infrared light receiving element 3. The following design is performed after a configuration is adopted in which only infrared light that has passed through the refraction lens 7 is received.

The light radiated from A is divided into optical paths K1A and K2.
A reaches the image point FA of A through A, K3A, K4A, and the like. As is well known in geometrical optics, the image point FA of A is formed on the opposite side of A with respect to the optical axis. As shown in FIG. 3, the light passing through the optical path K2A passes through the refractive lens 7, crosses the optical axis at F, reaches the FA, and moves away from the optical axis. Similarly, light passing through the optical path K1A passes through the refractive lens 7, crosses the optical axis, reaches the FA, and moves away from the optical axis. Optical path K
The light passing through 3A crosses the optical axis by the refraction lens 7, reaches the FA, and moves away from the optical axis. The light passing through the optical path K4A crosses the optical axis and passes through the refraction lens 7, and after passing through the refraction lens 7, reaches the FA without crossing the optical axis, and thereafter approaches or moves away from the optical axis. Go. Thus, A
There is an area where the light emitted from A does not pass at a position farther from the refraction lens than the image point FA. This area is
An optical path K4A at a portion farther from the refraction lens 7 than the FA;
Optical path K4A 'at a portion farther from refraction lens 7 than FA'
It is an area sandwiched by. By installing the infrared light receiving element 3 in this region, an optical system that does not receive infrared light emitted from A and A ′ can be realized.

It is well known that point B in the area of the inner wall of the probe 2 where light is not desired to be received is farther from the optical axis than A, so that the image point FB of B by the refracting lens 7 is farther from the optical axis than FA. is there. Therefore, by installing the infrared light receiving elements in a region sandwiched between the optical path K4A at a portion farther from the refracting lens 7 than the FA and the optical path K4A 'at a portion farther from the refracting lens 7 than the FA', A and A ' By not receiving the infrared rays radiated from B, the configuration is such that the infrared rays radiated from B are not automatically received.

As described above, the optical path K4A at a portion farther from the refraction lens 7 than the FA and the refraction lens 7
By installing the infrared light receiving element 3 in an area sandwiched between the optical paths K4A 'far from the optical axis, only the infrared light radiated from the area near the optical axis, that is, the eardrum and the vicinity thereof and passed through the probe 2 is received. Thus, a light receiving section as shown in FIG.

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a configuration diagram showing a light receiving unit and a probe of a radiation thermometer according to a third embodiment of the present invention. Here, unlike the above-described embodiment, the probe 2 has a rounded portion so that it can be more easily inserted into the ear canal.
In FIG. 4, 7 is a refractive lens, 3 is an infrared light receiving element, 2
4 is a housing. α and α ′ are virtual tip points where a straight line contacting the edge of the refractive lens 7 and the inner wall of the probe 2 on the same side with respect to this edge and the optical axis intersects the tip face of the probe 2, F is the focal point of the refractive lens 7, Fα, Fα ′ is an image point of α and α ′ by the refraction lens 7, respectively, K1α is an optical path of light (marginal ray) traveling from α to Fα through the edge of the refraction lens 7 on the same side with respect to the optical axis, and K2α. K3α is an optical path of light that travels from α in parallel with the optical axis, passes through the focal point F, and reaches Fα.
Is the optical path of light that reaches Fα from α through the center of the refraction lens 7, and K4α is the light (marginal ray) from α that passes through the edge of the refraction lens 7 on the opposite side of the optical axis and reaches Fα. K1α ′ is an optical path of light (marginal ray) traveling from α ′ to Fα ′ through the edge of the refractive lens 7 on the same side with respect to the optical axis, and K2α ′ is parallel to the optical axis from α ′. The optical path of the light that travels through the focal point F and reaches Fα ′, K
3α ′ passes through the center of the refractive lens 7 from α ′ and Fα ′
K4α ′ is the optical path of light (marginal ray) that passes through the edge of the refraction lens 7 on the opposite side of the optical axis from α ′ and reaches Fα ′, and FX is the optical path K1α and the optical axis. Is the intersection with

An optical system is designed so that only the infrared rays emitted from the eardrum and its vicinity and passing through the probe 2 are received by the infrared receiving element 3.

The infrared light receiving element 3 is mounted on the housing 24 so that only the infrared light passing through the refractive lens 7 is received by the infrared light receiving element 3. The following design is performed after a configuration is adopted in which only infrared light that has passed through the refraction lens 7 is received.

In order to receive only infrared light radiated from the eardrum and its vicinity and passed through the probe 2, infrared light radiated from the probe 2 may not be received. Therefore, a point located at the boundary between the region where light reception is desired and the region where light reception is not desired is imagined, and from this point, the refractive lens 7 on the same side with respect to the optical axis as the point located at this virtual boundary.
The probe 2 may be installed so as to be located farther from the optical axis than the optical path of the light (marginal ray) passing through the edge of. Therefore, a point located at the above-mentioned virtual boundary is defined as a position where the probe 2 on the same side as the edge and the optical axis from the edge of the refractive lens 7 is located.
The point α at which the straight line contacting the inner wall intersects the tip surface of the probe 2,
As α ′, the infrared light receiving element 3 is installed inside a triangle formed by Fα, Fα ′, and FX. As a result, the probe 2 is located farther from the optical axis than the optical paths K1α and K1α ′ between α and the refraction lens 7, so that an optical system that does not receive light from the probe 2 is obtained.

The above is described in detail below. The light emitted from α reaches the image point Fα of α through the optical paths K1α, K2α, K3α, K4α and the like. As is well known in geometrical optics, the image point Fα of α is formed on the opposite side of α with respect to the optical axis. As shown in FIG. 4, the light passing through the optical path K2α passes through the refractive lens 7, crosses the optical axis at F, and reaches Fα while leaving the optical axis. Similarly, the light passing through the optical path K1α passes through the refractive lens 7, crosses the optical axis, and then reaches Fα while leaving the optical axis. The light passing through the optical path K3α crosses the optical axis by the refractive lens 7 and then reaches Fα while leaving the optical axis. The light passing through the optical path K4α crosses the optical axis and passes through the refraction lens 7, and after passing through the refraction lens 7, reaches Fα without crossing the optical axis. As described above, there is a region where light emitted from α does not pass at a position farther from the refraction lens 7 than the point FX where the optical path K1α intersects the optical axis and closer to the refraction lens 7 than Fα. Similarly, the position of α ′ is farther from the refraction lens 7 than the point where the optical path intersects with the optical path K1α ′, and F ′
At a position closer to the refractive lens 7 than α ′, there is an area through which light emitted from α ′ does not pass. This Fα, F
By installing the infrared light receiving element 3 inside the triangle formed by α ′ and FX, a light receiving unit that does not receive light emitted from α and α ′ can be obtained. Light from a portion farther from the optical axis than the optical path K1α between α and the refracting lens 7 is replaced with light from a point whose distance from the optical axis is larger than α in the same plane as α. It is well known in geometrical optics that the image point at this point by the refraction lens 7 is farther from the optical axis than Fα. Therefore, if the light from α is not received,
It does not receive light from points farther from the optical axis than α, and therefore does not receive light from the probe 2. Similarly, light from a portion farther from the optical axis than the optical path K1α 'between α' and the refractive lens 7 is replaced with light from a point whose distance from the optical axis is larger than α 'in the same plane as α'. . Refraction lens 7 at this point
Is farther from the optical axis than Fα ′, as is well known in geometrical optics. Therefore, if light from α ′ is not received, light from a point farther from the optical axis than α ′ will not be received, and therefore no light from the probe 2 will be received. As described above, by disposing the infrared light receiving element 3 inside the triangle formed by Fα, Fα ′ and FX so as not to receive the infrared rays radiated from α and α ′, the probe 2 It does not receive infrared rays radiated from the camera.

Hereinafter, the position of the infrared light receiving element 3 which does not receive the light from α will be determined. The infrared light receiving element 3 is closer to the refractive lens 7 than Fα. At this time, the following equation is established.

LαF ≧ f + L3 (1) Therefore, L3 ≦ LαF−f (2) where f is the distance from the center of the LαF refracting lens 7 to the image point Fα of α, and f is the distance from the center of the refracting lens 7 to the focal point F. , L3 are distances from the focal point F to the infrared light receiving element 3.

As shown in FIG. 4, the light receiving surface is located between the points FX and Fα where the optical path K1α and the optical axis intersect.
K1α is the light path closest to the infrared light receiving element 3 on the light receiving surface among the optical paths up to α. Therefore, in order for the light from α to not be received by the infrared light receiving element 3, the following equation must be satisfied.

RαS1> rS (3) where rαS1 is the distance from the intersection FαS1 between the optical path K1α and the light receiving surface of the infrared light receiving element 3 to the optical axis, and rS is the radius of the infrared light receiving element 3. Also, let the radius of the refraction lens 7 be r
3. When the distance from the optical axis to the image point Fα is rαF,
As is well known in geometrical optics, r3, rαF, rαS1, L3,
f satisfies (Equation 4) as a geometric relationship.

[0058]

(Equation 5)

Therefore, (Equation 5) is satisfied.

[0060]

(Equation 6)

(Equation 6) is obtained by substituting (Equation 5) into (Equation 3).

[0062]

(Equation 7)

From (Equation 2) and (Equation 6), the condition for preventing the light radiated from α from being received by the infrared light receiving element 3 is (Equation 7).

[0064]

(Equation 8)

Further, the distance from α to the optical axis is rα, and the distance from the tip of the probe 2 to the center of the refractive lens 7 is Lα.
And, as is well known in geometrical optics, rα, Lα, r
αF and LαF satisfy (Equation 8) as a geometric relationship.

[0066]

(Equation 9)

Therefore, (Equation 9) is satisfied.

[0068]

(Equation 10)

By substituting (Equation 9) into (Equation 7), the condition for not receiving the light radiated from α by the infrared light receiving element 3 becomes (Equation 10).

[0070]

[Equation 11]

(Equation 11) holds from Gauss's formula.

[0072]

(Equation 12)

Therefore, (Equation 12) holds.

[0074]

(Equation 13)

By substituting (Equation 12) into (Equation 10), the condition for preventing the light radiated from α from being received by the infrared light receiving element 4 becomes (Equation 13).

[0076]

[Equation 14]

As described above, in order to prevent the light radiated from α at the tip of the probe 2 from being received by the infrared light receiving element 3,
It is necessary to design the optical system to satisfy (Expression 7), (Expression 10), or (Expression 13). (Equation 7), (Equation 1)
0), by displacing the infrared light receiving element 3 from the focal point of the refractive lens 7 by L3 given by (Equation 13),
The infrared light emitted from the probe 2 is not received by the infrared light receiving element 3 but is emitted from the eardrum and its vicinity.
Can be received by the infrared receiving element 3 only.

(Embodiment 4) Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a configuration diagram showing a light receiving unit and a probe of a radiation thermometer according to a fourth embodiment of the present invention. In FIG. 5, reference numeral 2 denotes a probe having a rounded portion as in the third embodiment. 7 is a refractive lens, 3 is an infrared light receiving element, and 24 is a housing. α and α ′ are virtual tip points where a straight line contacting the edge of the refractive lens 7 and the inner wall of the probe 2 on the same side with respect to this edge and the optical axis intersects the tip face of the probe 2, F is the focal point of the refractive lens 7, Fα, Fα '
Are the image points of α and α ′ by the refracting lens 7, respectively, K1α
Is the optical path of light (marginal ray) traveling from α to Fα through the edge of the refractive lens 7 on the same side with respect to the optical axis, K2
α is an optical path of light that travels from α in parallel with the optical axis and passes through the focal point F to reach Fα, K3α is an optical path of light that passes from α to Fα through the center of the refracting lens 7, and K4α is an optical path of α. The optical path of light (marginal ray) passing through the edge of the refractive lens 7 on the opposite side with respect to the optical axis and reaching Fα, K1α ′ is α ′
, An optical path of light (marginal ray) passing through the edge of the refractive lens 7 on the same side with respect to the optical axis and traveling to Fα ′, K2
α ′ proceeds from α ′ in parallel with the optical axis, passes through the focal point F, and
K3α ′ is the optical path of light reaching α ′, K3α ′ is the optical path of light reaching αα ′ through the center of the refraction lens 7, and K4
α ′ is an optical path of light (marginal ray) that passes through the edge of the refractive lens 7 on the opposite side of α ′ and reaches Fα ′, and FX is an intersection of the optical path K1α and the optical axis.

An optical system is designed such that only infrared rays emitted from the eardrum and its vicinity and passing through the probe 2 are received by the infrared receiving element 3.

The infrared light receiving element 3 is mounted on the housing 24 so that only the infrared light passing through the refractive lens 7 is received by the infrared light receiving element 3. The following design is performed after a configuration is adopted in which only infrared light that has passed through the refraction lens 7 is received.

In order to receive only infrared light radiated from the eardrum and its vicinity and passed through the probe 2, infrared light radiated from the probe 2 may not be received. Therefore, a point located at the boundary between the region where light reception is desired and the region where light reception is not desired is imagined, and from this point, the refractive lens 7 on the same side with respect to the optical axis as the point located at this virtual boundary.
The probe 2 may be installed so as to be located farther from the optical axis than the optical path of the light (marginal ray) passing through the edge of. Therefore, a point located at the above-mentioned virtual boundary is defined as a position where the probe 2 on the same side as the edge and the optical axis from the edge of the refractive lens 7 is located.
The point α at which the straight line contacting the inner wall intersects the tip surface of the probe 2,
As α ′, the infrared light receiving element 3 is installed in a region between the optical path K4α farther from the refractive lens 7 than Fα and the optical path K4α ′ farther from the refractive lens 7 than Fα ′. As a result, the probe 2 is located farther from the optical axis than the optical paths K1α and K1α ′ between α and the refraction lens 7, so that an optical system that does not receive light from the probe 2 is obtained.

The details will be described below. The light emitted from α reaches the image point Fα of α through the optical paths K1α, K2α, K3α, K4α and the like. As is well known in geometrical optics, the image point Fα of α is formed on the opposite side of α with respect to the optical axis. As shown in FIG. 5, the light passing through the optical path K2α passes through the refractive lens 7, crosses the optical axis at F, reaches Fα, and leaves the optical axis. Similarly, the light passing through the optical path K1α passes through the refractive lens 7, crosses the optical axis, reaches Fα, and moves away from the optical axis. The light passing through the optical path K3α crosses the optical axis by the refraction lens 7, reaches Fα, and moves away from the optical axis. Light passing through the optical path K4α crosses the optical axis and passes through the refractive lens 7, and after passing through the refractive lens 7, reaches Fα without crossing the optical axis, and then approaches or moves away from the optical axis. Go. As described above, there is a region where light emitted from α does not pass at a position farther from the refractive lens 7 than the image point Fα of α. Similarly, for α ′, there is a region where light emitted from α ′ does not pass at a position further from the refraction lens 7 than the image point Fα ′ of α ′. This, F
The optical path K4α at a portion farther from the refraction lens 7 than α, and F
By installing the infrared light receiving element in a region between the optical path K4α 'farther from the refraction lens 7 than α', a light receiving unit that does not receive the infrared rays emitted from α and α 'can be obtained. Light from a portion farther from the optical axis than the optical path K1α between α and the refracting lens 7 is replaced with light from a point whose distance from the optical axis is larger than α in the same plane as α. It is well known in geometrical optics that the image point at this point by the refraction lens 7 is farther from the optical axis than Fα. Therefore, if light from α is not received, light from a point farther from the optical axis than α will not be received, and therefore no light from probe 2 will be received. Similarly, the optical path K1 between α ′ and the refractive lens 7
Light from a portion farther from the optical axis than α ′ is replaced with light from a point greater than α ′ in the same plane as α ′. It is well known in geometrical optics that the image point at this point by the refraction lens 7 is farther from the optical axis than Fα ′. Therefore, if light from α ′ is not received, light from a point farther from the optical axis than α ′ will not be received, and therefore no light from the probe 2 will be received. Thus, F
The optical path K4α at a portion farther from the refraction lens 7 than α, and F
By placing the infrared light receiving element 3 in a region between the optical path K4α ′, which is farther from the refraction lens 7 than α ′, α,
If you do not receive infrared rays emitted from α ',
The configuration is such that infrared rays emitted from the probe 2 are not automatically received.

Hereinafter, the position of the infrared light receiving element 3 which does not receive the light from α will be obtained. The infrared light receiving element 3 is farther from the refraction lens 7 than Fα. At this time, the following equation is established.

LαF ≦ f + L3 (14) L3 ≧ LαF−f (15) where LαF is the distance from the center of the refractive lens 7 to the image point Fα of α, and f is the distance from the center of the refractive lens 7 to the focal point F. The distance L3 is the distance from the focal point F to the infrared light receiving element 3.

As shown in FIG. 5, since the light receiving surface is farther from the refracting lens 7 than Fα, K4α is the light receiving surface closest to the infrared light receiving element 3 in each of the optical paths from α to Fα. Therefore, in order for the light from α to not be received by the infrared light receiving element 3, the following equation must be satisfied.

RαS4> rS (16) where rαS4 is the distance from the intersection FαS4 between the optical path K4α and the light receiving surface of the infrared light receiving element 3 to the optical axis, and rS is the radius of the infrared light receiving element 3. Also, let the radius of the refraction lens 7 be r
3. When the distance from the optical axis to the image point Fα is rαF,
R3, rαF, LαF, rαS as is well known in geometrical optics
4, L3 and f satisfy (Equation 17) as a geometric relationship.

[0087]

(Equation 15)

Therefore, (Equation 18) is satisfied.

[0089]

(Equation 16)

By substituting (Equation 18) into (Equation 16), (Equation 19) is obtained.

[0091]

[Equation 17]

From (Equation 15) and (Equation 19), the condition for not receiving the light radiated from α by the infrared light receiving element 3 is (Equation 20).

[0093]

(Equation 18)

Further, the distance from α to the optical axis is rα, and the distance from the tip of the probe 2 to the center of the refractive lens 7 is Lα.
And, as is well known in geometrical optics, rα, Lα, r
αF and LαF satisfy the above (formula 8) as a geometric relationship. Therefore, the above (Equation 9) is satisfied.

By substituting (Equation 9) into (Equation 20), the condition for not receiving the light radiated from α by the infrared light receiving element 3 is (Equation 21).

[0096]

[Equation 19]

The above equation (Equation 1)
1) holds. Therefore, the above (Equation 12) holds.

By substituting (Equation 12) into (Equation 21), the condition for not receiving the light radiated from α by the infrared light receiving element 3 is (Equation 22).

[0099]

(Equation 20)

As described above, in order to prevent the light radiated from α from being received by the infrared light receiving element 3, the optical system must satisfy the condition of (Equation 20), (Equation 21), or (Equation 22). Need to be designed. (Equation 20), (Equation 21),
By disposing the light receiving element 3 from the focal point of the refractive lens 7 by L3 given by (Equation 22), the probe 2
Without receiving infrared rays emitted from the
Only infrared rays emitted from the eardrum and its vicinity and passed through the probe 2 can be received by the infrared receiving element 3.

In the above, an example in which a refraction lens is used as the light-collecting element of the light-receiving section has been described. However, even if a transmission-type diffractive lens is used, the infrared light-receiving element is similarly arranged to radiate light from the eardrum and its vicinity. The infrared light receiving element 3 can receive only the infrared light that has passed through the infrared light receiving element 2, and has an effect that the lens can be easily formed.

(Embodiment 5) Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a configuration diagram showing a light receiving unit and a probe of a radiation thermometer according to a fifth embodiment of the present invention. Here, the condensing element 7 uses a converging mirror unlike the above-described embodiment. In FIG. 6, 2 is a probe, 3
Is an infrared light receiving element, and 24 is a housing. α and α ′ are virtual tip points where a straight line contacting the edge of the condensing mirror 7 and the inner wall of the probe 2 on the same side with respect to this edge and the optical axis intersects the tip face of the probe 2, F is the focal point of the condensing mirror 7, Fα and Fα ′ are the image points of α and α ′ by the converging mirror 7, respectively, and K1α is reflected from α at the edge of the converging mirror 7 on the same side of the optical axis as F
The optical path of the light (marginal ray) traveling to α, K2α is α
K3α is the optical path of light that travels in parallel with the optical axis and passes through the focal point F to reach Fα, K3α is the optical path of light that reflects from α at the center of the condenser mirror 7 and reaches Fα, and K4α is the optical path that extends from α to α. K1α 'is an optical path of light (marginal ray) which is reflected at the edge of the condensing mirror 7 on the opposite side with respect to the optical axis and reaches Fα. And Fα '
K2α ′ is an optical path of light (marginal ray) that travels to α, an optical path of light that travels from α ′ in parallel with the optical axis and passes through the focal point F to reach Fα ′, and K3α ′ is an optical path of the focusing mirror 7 from α ′. K4α 'is an optical path of light (marginal ray) reflected from the center and reaching Fα' at an edge of the condensing mirror 7 on the opposite side of the optical axis from K '. , F
X is the intersection of the optical path K1α and the optical axis.

An optical system is designed so that the infrared light receiving element 3 receives only infrared light emitted from the eardrum and its vicinity and passing through the probe 2.

The infrared light receiving element 3 is mounted on the housing 24 so that only the infrared light reflected by the condenser mirror 7 is received by the infrared light receiving element 3. The following design is performed after a configuration in which only the infrared light reflected by the condenser mirror 7 is received.

In order to receive only the infrared light radiated from the eardrum and its vicinity and passed through the probe 2, the infrared light radiated from the probe 2 may not be received. Therefore, a point located at the boundary between the region where light reception is desired and the region where light reception is not desired is imagined, and the condensing mirror 7 on the same side of the optical axis as the point located at this virtual boundary is assumed.
The probe 2 may be installed so as to be located farther from the optical axis than the optical path of the light (marginal light ray) reflected at the edge of. Therefore, a point located on the virtual boundary is defined by moving the probe 2 from the edge of the condensing mirror 7 to the same side as the edge and the optical axis.
The point α at which the straight line contacting the inner wall intersects the tip surface of the probe 2,
As α ′, the infrared light receiving element 3 is installed inside a triangle formed by Fα, Fα ′, and FX. As a result, the probe 2 is located farther from the optical axis than the optical paths K1α and K1α ′ between α and the condensing mirror 7, so that an optical system that does not receive light from the probe 2 is obtained.

The above will be described in detail below. The light emitted from α reaches the image point Fα of α through the optical paths K1α, K2α, K3α, K4α and the like. As is well known in geometrical optics, the image point Fα of α is formed on the opposite side of α with respect to the optical axis. As shown in FIG. 6, the light passing through the optical path K2α is reflected by the condenser mirror 7, crosses the optical axis at F, and reaches Fα while leaving the optical axis. Similarly, light passing through the optical path K1α is reflected by the condenser mirror 7, crosses the optical axis, and then reaches Fα while leaving the optical axis. The light passing through the optical path K3α crosses the optical axis by the condenser mirror 7 and then reaches Fα while leaving the optical axis. The light passing through the optical path K4α crosses the optical axis and is reflected by the converging mirror 7, and after being reflected by the converging mirror 7, arrives at Fα without crossing the optical axis. As described above, there is a region where the light emitted from α does not pass at a position farther from the collecting mirror 7 than the point FX where the optical path K1α intersects with the optical axis and closer to the collecting mirror 7 than Fα. . Similarly, α ′ is also located at a position farther from the converging mirror 7 than at the point where the optical path intersects with the optical path K1α ′ and F
At a position closer to the condenser mirror 7 than α ′, there is a region through which light emitted from α ′ does not pass. This Fα, F
By installing the infrared light receiving element 3 inside the triangle formed by α ′ and FX, a light receiving unit that does not receive light emitted from α and α ′ can be obtained. Light from a portion farther from the optical axis than the optical path K1α between α and the condenser mirror 7 is replaced with light from a point whose distance from the optical axis is larger than α in the same plane as α. It is well known in geometrical optics that the image point of this point by the condenser mirror 7 is farther from the optical axis than Fα. Therefore, if the light from α is not received,
It does not receive light from points farther from the optical axis than α, and therefore does not receive light from the probe 2. Similarly, light from a portion farther from the optical axis than the optical path K1α 'between α' and the condensing mirror 7 is replaced with light from a point whose distance from the optical axis is larger than α 'in the same plane as α'. Can be Focusing mirror 7 at this point
Is farther from the optical axis than Fα ′, as is well known in geometrical optics. Therefore, if light from α ′ is not received, light from a point farther from the optical axis than α ′ will not be received, and therefore no light from the probe 2 will be received. As described above, by disposing the infrared light receiving element 3 inside the triangle formed by Fα, Fα ′ and FX so as not to receive the infrared rays radiated from α and α ′, the probe 2 It does not receive infrared rays radiated from the camera.

Hereinafter, the position of the infrared light receiving element 3 which does not receive the light from α will be obtained. The infrared light receiving element 3 is closer to the condenser mirror than Fα. At this time, (Equation 1) holds, and accordingly (Equation 2) holds. Here, LαF is the distance from the center of the condenser mirror 7 to the image point Fα of α, f is the distance from the center of the condenser mirror 7 to the focal point F, and L3 is the distance from the focal point F to the infrared light receiving element 3. .

As shown in FIG. 6, the light receiving surface is located between the points FX and Fα where the optical path K1α and the optical axis intersect.
K1α is the light path closest to the infrared light receiving element 3 on the light receiving surface among the optical paths up to α. Therefore, in order for the infrared light receiving element 3 not to receive the light from α, it is necessary to satisfy (Equation 3). Here, rαS1 is the distance from the intersection FαS1 between the optical path K1α and the light receiving surface of the infrared light receiving element 3 to the optical axis,
rS is the radius of the infrared light receiving element 3. In addition, the focusing mirror 7
Is r3, and the distance from the optical axis to the image point Fα is rαF, as is well known in geometrical optics, r3, rαF, rαS
1, L3, and f satisfy (Equation 4) as a geometric relationship, and thus satisfy (Equation 5). By substituting (Equation 5) into (Equation 3), (Equation 6) is obtained. (Equation 2), (Equation 6)
Therefore, the condition for not receiving light emitted from α by the infrared light receiving element 3 is (Equation 7).

Further, the distance from α to the optical axis is rα, and the distance from the tip of the probe 2 to the center of the focusing mirror 7 is Lα.
And, as is well known in geometrical optics, rα, Lα, r
αF and LαF satisfy (Equation 7) as a geometric relationship, and thus satisfy (Equation 9). By substituting (Equation 9) into (Equation 7), the light emitted from α
The condition for not receiving light is (Equation 10). (Equation 11) holds from Gauss's formula, and therefore,
(Equation 12) holds. By substituting (Equation 12) into (Equation 10), the light emitted from α
The condition for not receiving light is (Equation 13).

As described above, in order to prevent the light radiated from α at the tip of the probe 2 from being received by the infrared light receiving element 3,
It is necessary to design the optical system to satisfy (Expression 7), (Expression 10), or (Expression 13). (Equation 7), (Equation 1)
0), by displacing the infrared light receiving element 3 from the focal point of the condenser mirror 7 by L3 given by (Equation 13),
The infrared light emitted from the probe 2 is not received by the infrared light receiving element 3 but is emitted from the eardrum and its vicinity.
Can be received by the infrared receiving element 3 only.

(Embodiment 6) Next, a sixth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a configuration diagram showing a light receiving unit and a probe of a radiation thermometer according to a sixth embodiment of the present invention. In FIG. 7, 2 is a probe, 7 is a condenser mirror, 3 is an infrared light receiving element, and 24 is a housing. α and α ′ are virtual tip points where a straight line contacting the edge of the condensing mirror 7 and the inner wall of the probe 2 on the same side with respect to this edge and the optical axis intersects the tip face of the probe 2, F is the focal point of the condensing mirror 7, Fα, Fα '
Are the image points of α and α ′ by the focusing mirror 7, respectively, K1α
Is an optical path of light (marginal ray) reflected from the edge of the condenser mirror 7 on the same side of the optical axis from α and traveling to Fα, K2
α is an optical path of light traveling parallel to the optical axis from α and passing through the focal point F to reach Fα, K3α is an optical path of light which reflects from α at the center of the condensing mirror 7 and reaches Fα, and K4α is α K1α ′ is α ′, the optical path of the light (marginal ray) reflected from the edge of the condenser mirror 7 on the opposite side with respect to the optical axis and reaching Fα.
An optical path of light (marginal ray) that travels to Fα ′ through the edge of the condenser mirror 7 on the same side with respect to the optical axis, K2
α ′ proceeds from α ′ in parallel with the optical axis, passes through the focal point F, and
The optical path of light reaching α ′, K3α ′ is the optical path of light that reflects from α ′ at the center of the condenser mirror 7 and reaches Fα ′, K4
α ′ is an optical path of light (marginal ray) which is reflected by the edge of the condensing mirror 7 on the opposite side of α ′ with respect to the optical axis and reaches Fα ′, and FX is an intersection of the optical path K1α and the optical axis.

An optical system is designed so that only the infrared rays emitted from the eardrum and its vicinity and passing through the probe 2 are received by the infrared receiving element 3.

The infrared light receiving element 3 is mounted on the housing 24 so that only the infrared light reflected by the condenser mirror 7 is received by the infrared light receiving element 3. The following design is performed after a configuration in which only the infrared light reflected by the condenser mirror 7 is received.

In order to receive only the infrared light radiated from the eardrum and its vicinity and passed through the probe 2, the infrared light radiated from the probe 2 may not be received. Therefore, a point located at the boundary between the region where light reception is desired and the region where light reception is not desired is imagined, and the condensing mirror 7 on the same side of the optical axis as the point located at this virtual boundary is assumed.
The probe 2 may be installed so as to be located farther from the optical axis than the optical path of the light (marginal ray) reflected by the light source.
Therefore, the point located on the virtual boundary is referred to as the condensing mirror 7.
Points α and α ′ where a straight line that contacts the inner wall of the probe 2 on the same side as the optical axis from this edge intersects the distal end surface of the probe 2
And the optical path K at a portion farther from the focusing mirror 7 than Fα
The infrared light receiving element 3 is installed in a region between 4α and the optical path K4α ′ farther from the light collecting mirror 7 than Fα ′.
As a result, the probe 2 is located farther from the optical axis than the optical paths K1α and K1α ′ between α and the condensing mirror 7, so that an optical system that does not receive light from the probe 2 is obtained.

The details will be described below. The light emitted from α reaches the image point Fα of α through the optical paths K1α, K2α, K3α, K4α and the like. As is well known in geometrical optics, the image point Fα of α is formed on the opposite side of α with respect to the optical axis. As shown in FIG. 7, the light passing through the optical path K2α is reflected by the condenser mirror 7, crosses the optical axis at F, reaches Fα, and moves away from the optical axis. Similarly, light passing through the optical path K1α is reflected by the condenser mirror 7, crosses the optical axis, reaches Fα, and moves away from the optical axis. The light passing through the optical path K3α crosses the optical axis at the condenser mirror 7, reaches Fα, and moves away from the optical axis. The light passing through the optical path K4α crosses the optical axis and is reflected by the converging mirror 7, and after being reflected by the converging mirror 7, reaches Fα without crossing the optical axis and then approaches the optical axis or Go away. As described above, there is a region where light emitted from α does not pass at a position further from the light collecting mirror 7 than the image point Fα of α. Similarly, for α ′, there is a region where light emitted from α does not pass at a position further from the light collecting mirror 7 than the image point Fα of α. By setting the infrared light receiving element 3 in an area between the optical path K4α farther from the converging mirror 7 than Fα and the light path K4α ′ farther from the converging mirror 7 than Fα ′, α ,
A light receiving portion that does not receive the infrared radiation radiated from α ′ is obtained. Light from a portion farther from the optical axis than the optical path K1α between α and the condenser mirror 7 has a distance α from the optical axis within the same plane as α.
Replaced by light from a larger point. It is well known in geometrical optics that the image point of this point by the condenser mirror 7 is farther from the optical axis than Fα. Therefore, if light from α is not received, light from a point farther from the optical axis than α will not be received, and therefore no light from probe 2 will be received. Similarly, the optical path K1α ′ between α ′ and the condenser mirror 7
Light from a portion farther from the optical axis is replaced with light from a point greater than α ′ in the same plane as α ′. It is well known in geometrical optics that the image point at this point by the condenser mirror 7 is farther from the optical axis than Fα ′.
Therefore, if the light from α 'is not received,
It does not receive light from points farther from the optical axis than α ′, and therefore does not receive light from the probe 2. As described above, the optical path K4α at a portion farther from the converging mirror 7 than Fα and Fα ′
If the infrared light receiving element 3 is installed in a region between the optical paths K4α 'farther from the converging mirror 7 so as not to receive infrared rays emitted from α and α', the probe is automatically 2 does not receive the infrared rays radiated therefrom.

Hereinafter, the position of the infrared light receiving element 3 which does not receive the light from α will be obtained. The infrared light receiving element 3 is farther from the light collecting mirror 7 than Fα. At this time, (Equation 14) holds, and therefore (Equation 15) holds. Here, LαF is the distance from the center of the condenser mirror 7 to the image point Fα of α, f is the distance from the center of the condenser mirror 7 to the focal point F, and L3 is the distance from the focal point F to the infrared light receiving element 3. .

As shown in FIG. 7, since the light receiving surface is farther from the focusing mirror 7 than Fα, K4α is the light receiving surface closest to the infrared light receiving element 3 among the light paths from α to Fα. Therefore, in order for the light from α to not be received by the infrared light receiving element 3, it is necessary to satisfy (Equation 16). Here, rαS4 is the distance from the intersection FαS4 between the optical path K4α and the light receiving surface of the infrared light receiving element 3 to the optical axis, and rS is the radius of the infrared light receiving element 3. Assuming that the radius of the focusing mirror 7 is r3 and the distance from the optical axis to the image point Fα is rαF, r3, rαF, LαF, rαS4, L
3, f satisfies (Equation 17) as a geometric relationship, and thus satisfies (Equation 18). (Equation 19) is obtained by substituting (Equation 16) into (Equation 16). From (Equation 15) and (Equation 19), the condition for not receiving the light emitted from α by the infrared receiving element 3 is (Equation 20).

Further, the distance from α to the optical axis is rα, and the distance from the tip of the probe 2 to the center of the focusing mirror 7 is Lα.
And, as is well known in geometrical optics, rα, Lα, r
αF and LαF satisfy (Expression 8) as a geometric relationship, and therefore satisfy (Expression 9). By substituting (Equation 9) into (Equation 20), the light emitted from α
The condition for not receiving light is (Equation 21). Also, since (Equation 11) holds from Gauss's formula, (Equation 12)
Holds. By substituting (Equation 12) into (Equation 21), the condition for not receiving light emitted from α by the infrared light receiving element 3 is (Equation 22).

As described above, in order to prevent the light radiated from α from being received by the infrared light receiving element 3, the optical system must satisfy the condition of (Equation 20), (Equation 21), or (Equation 22). Need to be designed. (Equation 20), (Equation 21),
By disposing the infrared light receiving element 3 from the focal point of the condensing mirror 7 by L3 given by (Equation 22), the infrared light radiated from the probe 2 is not received by the infrared light receiving element 3 and the eardrum is received. Only infrared rays emitted from the vicinity and passing through the probe 2 can be received by the infrared receiving element 3.

In the above, an example in which a light-collecting mirror is used as the light-collecting element of the light-receiving section has been described. However, compared with the case of using a refractive lens, there is an effect of increasing the amount of received light without transmission loss. Similarly, the infrared light receiving element 3
In addition to the arrangement, only infrared rays emitted from the eardrum and its vicinity and passed through the probe 2 can be received by the infrared light receiving element 3, and the mirror can be easily formed.

[0121]

As described above, the radiation thermometer of the present invention has the following effects.

According to the radiation thermometer according to the first aspect of the present invention, the output from the light receiving section which receives only infrared rays directly radiated from the eardrum and its vicinity is calculated into the temperature by the signal processing means, and the information is notified by the notification means. Therefore, it is not affected by heat radiation from portions other than the eardrum and its vicinity. That is, since there is no influence of the radiation heat radiated from the probe, it is not necessary to measure the temperature of the probe, and it is not necessary to provide a waveguide for blocking the radiation heat from the probe, so that an accurate eardrum temperature can be detected.

According to the radiation thermometer according to the second aspect of the present invention, the light receiving section receives only infrared rays radiated from the eardrum and its vicinity and passed through the probe, and the signal processing means calculates the output from the light receiving section into temperature. Then, the notifying means notifies the temperature of the calculation result. The infrared light condensed by the light-collecting element enters the infrared light-receiving element of the light-receiving section, and the infrared light-receiving element is located away from the focal position of the light-collecting element, so that it is collected from the inner wall of the probe. Infrared rays incident on the element can be advanced to positions other than the infrared light receiving element, and the light receiving area can be limited. As a result, only the radiation emitted from the eardrum and its vicinity and passed through the probe can be detected as a spot, and the accurate eardrum temperature can be detected.

According to the radiation thermometer according to the third aspect of the present invention, the infrared light receiving element passes through the edge of the light collecting element on the same side as the virtual tip point and reaches the image point of the virtual tip point by the light collecting element. Infrared light incident on the light-collecting element from the inner wall of the probe by installing it in a region farther from the light-collecting element than the intersection of the optical path and the optical axis and closer to the light-collecting element than the image point of the virtual tip point by the light-collecting element Can be advanced to a position other than the infrared light receiving element, and the light receiving area can be limited. As a result, only the radiation emitted from the eardrum and its vicinity and passed through the probe can be detected as a spot, and the accurate eardrum temperature can be detected.

According to the radiation thermometer according to the fourth aspect of the present invention, the infrared light receiving element passes through the edge of the light-collecting element on the same side as the virtual point and reaches the image point of the virtual point by the light-collecting element. The light collector is located within a triangle in the meridional plane of the light collector, which is formed by two intersections of the optical path and the optical axis to be formed and the virtual image point of the light collector. Can be made to travel to positions other than the infrared light receiving element, and the light receiving area can be limited. As a result, only the radiation emitted from the eardrum and its vicinity and passed through the probe can be detected as a spot, and the accurate eardrum temperature can be detected.

According to the radiation thermometer according to the fifth aspect of the present invention, the infrared light receiving element is in contact with the inner wall of the probe on the same side as the edge of the light collecting element with respect to the optical axis from the edge of the light collecting element. By setting the straight line drawn in a region farther from the light-collecting element than the image point of the light-collecting element at the virtual tip point intersecting with the surface of the tip of the probe, infrared rays incident on the light-collecting element from the inner wall of the probe can be detected. The light can be moved to a position other than the infrared light receiving element, and the light receiving area can be limited. As a result, only the radiation emitted from the eardrum and its vicinity and passed through the probe can be detected as a spot, and the accurate eardrum temperature can be detected.

According to the radiation thermometer according to the sixth aspect of the present invention, the infrared light receiving element is in contact with the inner wall of the probe on the same side as the edge of the light collecting element with respect to the optical axis from the edge of the light collecting element. A straight line drawn from the virtual tip point intersects the surface of the tip of the probe, passes through the edge of the light-collecting element opposite to the virtual tip point across the optical axis, and the virtual tip point by the light-collecting element By placing it in a region between two optical paths in the meridional plane of the light-collecting element that reaches the image point of the above, the infrared light incident on the light-collecting element from the inner wall of the probe proceeds to a position other than the infrared light-receiving element And the light receiving area can be limited. As a result, only the radiation emitted from the eardrum and its vicinity and passed through the probe can be detected as a spot, and the accurate eardrum temperature can be detected.

According to the radiation thermometer according to the seventh aspect of the present invention, the infrared light receiving element has a focal length f of the light condensing element, a radius rS of the infrared light receiving element, and a distance rα between the virtual tip point and the optical axis.
Using the distance Lα between the virtual tip point and the light-collecting element and the radius r3 of the light-collecting element, L3 given by the above (Equation 13) is obtained.
Only by installing it farther from the light-collecting element than the light-focusing element, infrared light entering the light-collecting element from the inner wall of the probe can travel to positions other than the infrared light-receiving element, thereby limiting the light-receiving area. Can be. As a result, only the radiation emitted from the eardrum and its vicinity and passed through the probe can be detected as a spot, and the accurate eardrum temperature can be detected.

According to the radiation thermometer according to claim 8 of the present invention, the infrared light receiving element has a focal length f of the light collecting element, a radius rS of the infrared light receiving element, and a distance rα between the virtual tip point and the optical axis.
Using the distance Lα between the virtual tip point and the light-collecting element and the radius r3 of the light-collecting element, L expressed by the above (Equation 22) is used.
By installing the light collecting element 3 farther from the light collecting element than the focal point of the light collecting element, infrared rays incident on the light collecting element from the inner wall of the probe can be advanced to positions other than the infrared light receiving element, thereby limiting the light receiving area. can do. As a result, only the radiation emitted from the eardrum and its vicinity and passed through the probe can be detected as a spot, and the accurate eardrum temperature can be detected.

According to the radiation thermometer according to the ninth aspect of the present invention, the focused infrared rays enter the infrared light receiving element by the refraction lens, so that the light receiving area can be limited and the eardrum and its vicinity can be restricted. Only the emitted light that has been emitted and passed through the probe can be detected as a spot,
Accurate eardrum temperature can be detected.

According to the radiation thermometer according to the tenth aspect of the present invention, since the condensed infrared light enters the infrared light receiving element by the transmission type diffraction lens, the light receiving area can be limited, and the eardrum and its Only the radiation emitted from the vicinity and passing through the probe can be detected as a spot, which has the effect of being able to accurately detect the eardrum temperature and of being easily manufactured.

According to the radiation thermometer according to the eleventh aspect of the present invention, the condensed infrared rays are incident on the infrared light receiving element by the condensing mirror, so that the light receiving area can be limited, and the eardrum and its vicinity can be limited. In addition to being able to detect only the radiation emitted from the probe and passing through the probe as a spot, accurate eardrum temperature can be detected, and there is no transmission loss and the infrared light is effectively guided to the infrared light receiving element. is there.

Further, according to the radiation thermometer according to the twelfth aspect of the present invention, since the condensed infrared rays enter the infrared light receiving element by the reflection type diffraction lens, the light receiving area can be limited and the eardrum and the eardrum can be measured. Only the radiation emitted from the vicinity and passing through the probe can be detected as a spot, enabling accurate detection of the eardrum temperature and the effective transmission of infrared light to the infrared light receiving element without transmission loss Has an effect,
Further, there is an effect that manufacturing is easy.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a radiation thermometer according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of a light receiving unit of the embodiment.

FIG. 3 is an enlarged view of a main part of a light receiving unit according to a second embodiment of the present invention.

FIG. 4 is an enlarged view of a main part of a light receiving unit according to a third embodiment of the present invention.

FIG. 5 is an enlarged view of a main part of a light receiving unit according to a fourth embodiment of the present invention.

FIG. 6 is an enlarged view of a main part of a light receiving unit according to a fifth embodiment of the present invention.

FIG. 7 is an enlarged view of a main part of a light receiving unit according to a sixth embodiment of the present invention.

FIG. 8 is a configuration diagram of a radiation thermometer in the first conventional example.

FIG. 9 is a configuration diagram of a radiation thermometer in a second conventional example.

FIG. 10 is a configuration diagram of a light receiving unit of a radiation thermometer according to a third conventional example.

FIG. 11 is a characteristic diagram showing a relationship between a reflection angle and an emissivity of a reflection material.

[Explanation of symbols]

 2 Probe 3 Infrared light receiving element 7 Condensing element 18 Light receiving section 22 Signal processing means 23 Notification means

Continued on the front page (72) Inventor Makoto Shibuya 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Person Kanji Nishii 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture (72) Inventor Kazuma Takada 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (12)

[Claims] 1. A light receiving unit for receiving only infrared rays directly radiated from the eardrum and its vicinity, a signal processing unit for calculating an output of the light receiving unit to a temperature, and a notifying unit for notifying an output of the signal processing unit. A radiation thermometer with a configuration that is not affected by heat radiation from areas other than the eardrum and its vicinity. 2. A probe that is inserted into the ear canal, fixes the orientation of the eardrum, and passes infrared light radiated from the eardrum and its vicinity, a light receiving unit that receives the infrared light that has passed through the probe, and an output of the light receiving unit. A signal processing means for calculating the signal processing means, and a notifying means for notifying the output of the signal processing means, wherein the light receiving unit is a light-collecting element that collects at least the infrared light that has passed through the probe, and is collected by the light-collecting element. 2. A light receiving area is limited by having an infrared light receiving element for receiving infrared light, and installing the infrared light receiving element at a position rearward from a focal position of the light collecting element.
The described radiation thermometer. 3. A straight line drawn from the edge of the light-collecting element so as to be in contact with the inner wall of the probe on the same side as the edge of the light-collecting element with respect to the optical axis. Intersecting point between the optical path and the optical path that passes from the intersecting virtual tip point to the image point of the virtual tip point by the light collecting element through the edge of the light condensing element on the same side as the virtual tip point with respect to the optical axis The radiation thermometer according to claim 1, wherein the thermometer is located farther from the light-collecting element and closer to the light-collecting element than an image point of the virtual tip point by the light-collecting element. 4. A line formed by drawing an infrared light receiving element from the edge of the light-collecting element so as to be in contact with the inner wall of the probe on the same side as the edge of the light-collecting element with respect to the optical axis. Intersecting point between the optical path and the optical path that passes from the intersecting virtual tip point to the image point of the virtual tip point by the light collecting element through the edge of the light condensing element on the same side as the virtual tip point with respect to the optical axis The radiation thermometer according to any one of claims 1 to 3, wherein the radiation thermometer is provided within a triangle in a meridional plane of the light-collecting element formed by the light-collecting element and two image points of the virtual tip point. . 5. A straight line drawn from an edge of the light-collecting element so as to be in contact with the inner wall of the probe on the same side as the edge of the light-collecting element from the edge of the light-collecting element. The radiation thermometer according to claim 1, wherein the virtual thermometer is located in a region farther from the light converging element than an image point of the converging virtual tip point by the light converging element. 6. A straight line drawn from an edge of the light-collecting element so as to be in contact with the inner wall of the probe on the same side as the edge of the light-collecting element with respect to the optical axis from the edge of the light-collecting element. The meridian of the light-collecting element that passes through the edge of the light-collecting element on the opposite side of the virtual axis from the virtual point that intersects the optical axis and reaches the image point of the virtual point by the light-collecting element. 6. The radiation thermometer according to claim 1, wherein the radiation thermometer is installed in an area between two optical paths in a plane. 7. The infrared light receiving element is connected to a focal length f of the light collecting element.
And a radius rS of the infrared light receiving element, and a straight line drawn from the edge of the light collecting element so as to be in contact with the inner wall of the probe on the same side as the edge of the light collecting element with respect to the optical axis. Using the distance rα between the virtual tip point and the optical axis intersecting with the distance, the distance Lα between the virtual tip point and the light-collecting element, and the radius r3 of the light-collecting element, The radiation thermometer according to claim 1, wherein the radiation thermometer is installed farther from the light-collecting element than the focal point of the light-collecting element by L3 given by: 8. The infrared light receiving element is provided with a focal length f of a light collecting element.
A radius rS of the infrared light receiving element, and a straight line drawn from the edge of the light-collecting element so as to be in contact with the inner wall of the probe on the same side as the edge of the light-collecting element with respect to the optical axis. The distance rα between the virtual tip point intersecting the surface of
Using the distance Lα between the virtual tip point and the light-collecting element and the radius r3 of the light-collecting element, The radiation thermometer according to claim 1, wherein the radiation thermometer is disposed farther from the light-collecting element than the focal point of the light-collecting element by L3 represented by: 9. The radiation thermometer according to claim 1, wherein the light-collecting element is a refractive lens. 10. The radiation thermometer according to claim 1, wherein the light-collecting element is a transmission diffraction lens. 11. The radiation thermometer according to claim 1, wherein the light-collecting element is a light-collecting mirror. 12. The radiation thermometer according to claim 1, wherein the light-collecting element is a reflection type diffraction lens.