JP2002340680A - Infrared detector and radiation thermometer using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem in conventional infrared detector that precise temperature detection cannot be performed because of a wide visual field. SOLUTION: This infrared detector has a converging element 13 for converging the infrared ray radiated from a measuring object 3, an infrared receiving element 12 for receiving the infrared light converged by the converging element 13, a cylindrical probe 15 having an opening part 15a for passing the infrared light from the measuring object to the converging element 13, and a shielding body 14 for shielding the incidence of the infrared light out of the converging element 13 on the receiving element 12, and further has a moving means 24 for separating the light receiving element 12 backward from the focal position of the converging element 13 and moving the converging element 13. Accordingly, since the visual field is narrowed down by the converging element 13, and the temperature detection is performed while moving the converging element 13, this detector has the effect that the highest temperature can be precisely detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared detector for detecting infrared radiation emitted from an object, and a radiation thermometer using the infrared detector.

[0002]

2. Description of the Related Art Conventionally, an infrared detector of this type and a radiation thermometer using the infrared detector are disclosed in Japanese Patent Application Laid-Open No. 8-254466.
What was described in the gazette was common. The principle of detecting infrared rays by the infrared detector 1 will be described below with reference to FIG.

[0003] Every object emits infrared rays according to its absolute temperature, and the infrared detector 1 detects the infrared rays. The infrared detector 1 includes an infrared light receiving element 2 that receives infrared light and outputs a signal, and a waveguide 4 that guides infrared light emitted from the device under test 3 to the infrared light receiving element 2.
And The waveguide 4 is made of metal, and its inner surface is mirror-finished so as to enhance the reflection of infrared rays.

[0004] Infrared rays emitted from the device under test 3 are directly incident on the infrared light receiving element 2 as shown by a broken line A, or are received while repeating reflection on the inner surface of the waveguide 4 as shown by a dashed line B. Light enters the element 2. Accordingly, the light receiving area is wide, and a wide range of infrared light enters the infrared light receiving element 2.

The output signal voltage V of the infrared light receiving element 2 is such that when an infrared light receiving element 2 using a thermal element such as a pyroelectric element or a thermopile is used, the absolute temperature of the DUT 3 is Tt, Assuming that the absolute temperature of the element 2 is Ts, it is represented by (Equation 3) (K is a proportional constant).

[0006]

(Equation 3)

This is because the infrared light receiving element 2 is
Means that an output signal proportional to the fourth power of the absolute temperature of the infrared light receiving element 2 and the fourth power of the absolute temperature of the infrared light receiving element 2 itself is generated. Therefore, the temperature difference between the DUT 3 and the infrared light receiving element 2 itself can be detected from the output signal of the infrared light receiving element 2.

A conventional example in which the infrared detector 1 is applied to a radiation thermometer 5 will be described below with reference to FIG. The radiation thermometer 5 shown in FIG.
A temperature measuring element 6 such as a thermistor for detecting the temperature of the infrared detector 1, a probe 7 having an opening 7a through which infrared rays pass, and a body temperature calculated from an output signal of the infrared detector 1 and an output signal of the temperature measuring element 6. An electronic circuit (signal processing means) 8 including a microcomputer to perform the calculation, a liquid crystal display device 9 (display means) for displaying the calculated body temperature, and a main body case 10 for housing these. The probe 7 and the main body case 10 are generally formed of resin. At this time, the waveguide 4 is extended to the tip of the probe 7 so as to penetrate the probe 7.

When measuring the body temperature, the probe 1 is inserted into the ear canal 3a, whereby the infrared detector 1 receives infrared rays radiated from the eardrum 3b and its vicinity and outputs a signal. The signal processing means 8 relates to a signal relating to the temperature difference between the eardrum 3 b and its vicinity and the infrared light receiving element 2 output from the infrared light receiving element 2 and the temperature of the infrared light receiving element 2 output from the temperature measuring element 6. The temperature of the eardrum and its vicinity is calculated from both signals and displayed on the display means 9 as the body temperature.

The reason for measuring the body temperature in the eardrum 3b is as follows.
Near the eardrum 3b, there is an arterial blood flow to the hypothalamus, which is a center for controlling body temperature, and it is said that the temperature of the eardrum 3b well reflects the body temperature in the deep part of the human body. for that reason,
The radiation thermometer 5 is put into practical use as a type that is inserted into the external auditory meatus 3a and measures the temperature of the eardrum 3b and its vicinity.

Next, the reason why the waveguide 4 is penetrated to the tip of the probe 7 will be described. When measuring the body temperature, the probe 7 is inserted into the external auditory meatus 3a, so that the temperature of the probe 7 in contact with the external auditory meatus 3a increases. As described with reference to FIG. 9, since the light receiving area of the infrared detector 1 is wide, if the infrared ray radiated from the probe 7 whose temperature has risen enters the infrared light receiving element 2, it becomes a measurement error and an accurate measurement cannot be performed. Therefore, the waveguide 4 is prevented from entering unnecessary infrared rays from the probe 7 whose temperature rises.
Is penetrated to the tip of the probe 7, and the inner surface of the waveguide 4 is mirror-finished so as to suppress infrared radiation as much as possible to reduce the emissivity. As a result, even if the temperature of the ear canal 3a is transmitted to the waveguide 4 via the probe 7 and the temperature of the waveguide 4 rises, infrared radiation should be reduced.

However, it is difficult to make the inner surface of the waveguide 4 a perfect reflector (reflectance = 1), and since the waveguide 4 is installed close to the probe 7, its temperature rises. Inevitably, the radiation of infrared radiation from the inner surface of the waveguide 4 cannot be completely eliminated. Therefore, when the body temperature is measured, the infrared radiation radiated from the waveguide 4
And accurate measurement of the body temperature cannot be performed.

In the conventional example, in order to solve this problem, the waveguide 4 is made of a metal having a high thermal conductivity, and the waveguide 4, the infrared light receiving element 2 and the thermistor 6 are installed with good thermal coupling. . In this way, the heat from the external auditory canal 3a is hardly affected, and the received heat is quickly conducted to the infrared light receiving element 1 to eliminate the influence.

Further, in the radiation thermometer disclosed in Japanese Patent Application Laid-Open No. 8-191800, a temperature measuring element for detecting the temperature of the waveguide 4 is provided, and by making corrections, the influence of heat is removed. ing.

[0015]

However, in the above-mentioned conventional infrared detector and a radiation thermometer using the same,
In order to accurately measure the temperature of the eardrum and its vicinity in order to eliminate the effect of heat transmitted from the ear canal, which is the object to be measured, to the waveguide via the probe, none of the above methods is perfect, There is a problem that a measurement error occurs due to the influence of the temperature rise of the wave tube, and the accuracy of the body temperature measurement is lacking.

In the above-described conventional configuration, infrared rays from the eardrum and its vicinity to the ear canal enter the infrared receiving element. As a result, the measured value is an average value of the temperature in a wide range including the eardrum and the ear canal. The temperature inside the ear canal is the highest in the eardrum and its vicinity, and gradually decreases as it goes outside the ear canal due to the influence of external air and the like. Therefore, there is a problem that it is unclear whether the measured value indicates an accurate body temperature.

The present invention solves the above-mentioned conventional problems and eliminates the influence of the heat transmitted from the ear canal to the probe on the measured value, and makes it possible to measure a narrow range by condensing infrared light by a light condensing element. The provision of the moving means for moving the infrared light receiving element makes it possible to measure the temperature distribution inside the ear canal, thereby realizing accurate measurement of body temperature.

[0018]

In order to solve the above-mentioned problems, an infrared detector according to the present invention comprises at least a light-collecting element for collecting infrared rays radiated from an object to be measured, and a light-collecting element. An infrared light receiving element for receiving the emitted infrared light, a cylindrical probe through which infrared light from the object to be measured is transmitted to the light collecting element, and an infrared light from outside the light collecting element being incident on the infrared light receiving element. A light-shielding body that blocks light, moving the infrared light receiving element backward from the focal position of the light collecting element to limit a light receiving area, and moving the light collecting element at least in a direction perpendicular to an optical axis. Means.

According to the above invention, the infrared ray receiving element is set apart from the focal point of the light-collecting element, so that infrared rays entering the light-collecting element from an unnecessary area can be advanced to positions other than the infrared ray receiving element. Comes out.

Therefore, the light receiving area is limited, and is not affected by the probe whose temperature rises due to heat transmitted from the object to be measured.
A waveguide is not required, and a measurement error can be suppressed.

The temperature distribution of a non-measurement object can be measured by installing the light-collecting element so as to be movable at least in a direction perpendicular to the optical axis.

The infrared detector, a temperature measuring element for detecting the temperature of the infrared detector, signal processing means for calculating a body temperature from an output signal of the infrared detector and an output signal of the temperature measuring element, A radiation thermometer having a display means for displaying the calculated body temperature and a main body containing the infrared detector was provided.

According to the above invention, it is possible to provide a radiation thermometer which limits the light receiving area and does not receive infrared rays from the probe. Therefore, only infrared light from the eardrum, which is the object to be measured, and its vicinity can be made incident on the infrared light receiving element, and infrared light from the external auditory canal does not enter the infrared light receiving element. Even so, it is possible to realize a radiation thermometer capable of measuring an accurate temperature distribution.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An infrared detector according to a first aspect of the present invention comprises at least a light-collecting element for collecting infrared light radiated from an object to be measured, and an infrared light collected by the light-collecting element. An infrared light receiving element for receiving light, a cylindrical probe through which infrared light traveling from the object to be measured to the light-collecting element passes, and a light shield that blocks infrared light from outside the light-collecting element from entering the infrared light receiving element. Having a moving means for limiting the light receiving area by moving the infrared light receiving element backward from the focal position of the light collecting element, and moving the light collecting element at least in a direction perpendicular to the optical axis. did.

By arranging the infrared light receiving element away from the focal position of the light collecting element, light incident on the light collecting element from an unnecessary area can be advanced to a position other than the infrared light receiving element. Accordingly, since the light receiving area is limited and the infrared rays from the probe are condensed on points other than the light receiving element, it is possible to realize a configuration in which the temperature can be accurately detected without being affected by the temperature rise of the probe. In addition, the temperature distribution of the non-measurement object can be measured by providing a moving unit that moves the light-collecting element at least in a direction perpendicular to the optical axis.

According to a second aspect of the present invention, in the infrared detector, the infrared light receiving element is moved from an edge closest to the probe of the light-collecting element that has moved to the maximum with respect to an optical axis of the light-collecting element. From the point where a straight line drawn so as to be in contact with the inner wall of the probe on the same side intersects the front end surface of the probe, the collection of points passing through the edge of the light condensing element and intersecting the front end surface of the probe. The point which is farther from the light-collecting element than the intersection of the optical path reaching the image point by the optical element and the central axis of the probe, and intersects with the surface of the tip of the probe is more concentrated than the image point by the light-collecting element. It was configured to be installed in a region near the optical element.

Thus, since the light receiving area is limited and the infrared rays from the probe are condensed on points other than the light receiving element, it is possible to realize a structure capable of accurately detecting the temperature without being affected by a rise in the temperature of the probe. .

According to a third aspect of the present invention, in the infrared detector, the infrared light receiving element may be the same as the edge of the light collecting element with respect to the optical axis from the edge closest to the probe of the light collecting element that has been moved to the maximum. The light-collecting element at a point where a straight line drawn so as to be in contact with the inner wall of the probe at the side intersects the surface of the probe tip and passes through the edge of the light-collecting element and intersects the surface of the probe tip. A point at which the optical path reaching the two image points crosses the central axis of the probe, and a point at which the light converging element intersects the surface of the probe tip,
The image point is installed inside a triangle formed by a symmetrical point with respect to the center axis of the probe.

Thus, since the light receiving area is limited and the infrared rays from the probe are condensed on points other than the light receiving element, it is possible to realize a structure capable of accurately detecting the temperature without being affected by the temperature rise of the probe. .

According to a fourth aspect of the present invention, in the infrared detector, the infrared light receiving element is provided with a focal length f of the light collecting element.
A radius rs of the infrared light receiving element and an edge closest to the probe of the light-collecting element that has been moved to the maximum so as to contact 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 optical axis and the point where the straight line intersects the surface of the probe tip, and the same side as the edge of the light-collecting element with respect to the optical axis from the edge closest to the probe of the light-collecting element that has moved the maximum. The distance Lα between the point where the straight line drawn so as to be in contact with the inner wall of the probe and the surface of the tip of the probe and the light-collecting element, the radius r3 of the light-collecting element, and the probe of the light-collecting element Using the maximum movement distance d from the central axis of

[0031]

(Equation 4)

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

Thus, since the light receiving area is limited and the infrared rays from the probe are condensed on points other than the light receiving element, it is possible to realize a structure capable of accurately detecting the temperature without being affected by the temperature rise of the probe.

According to a fifth aspect of the present invention, in the infrared detector, the infrared light receiving element is arranged at the same position as the edge of the light-collecting element with respect to the optical axis from the edge closest to the probe of the light-collecting element that has been moved to the maximum. The point where the straight line drawn so as to be in contact with the inner wall of the probe on the side intersects the surface of the tip of the probe is located farther from the light-collecting element than the image point by the light-collecting element.

As a result, the light receiving area is limited and the infrared rays from the probe are condensed on points other than the light receiving element, so that the temperature can be accurately detected without being affected by the temperature rise of the probe. .

According to a sixth aspect of the present invention, in the infrared detector, the infrared light receiving element is located on the same side as the edge of the light-collecting element with respect to the optical axis from the edge closest to the probe of the light-collecting element that has moved as far as possible. From the point where the straight line drawn so as to be in contact with the inner wall of the probe intersects with the surface of the tip of the probe, passes through the opposite edge across the optical axis of the light-collecting element and intersects with the surface of the tip of the probe. The point at which the optical path reaching the image point by the light-collecting element intersects the center axis of the probe, the image point by the light-collecting element at the point intersecting the surface of the probe tip, and the image point of the image point The infrared light receiving element was installed inside a triangle formed by a point of symmetry with respect to the center axis of the infrared light receiving element.

As a result, since the light receiving area is limited and infrared rays from the probe are focused on points other than the light receiving element, it is possible to realize a structure capable of accurate temperature detection without being affected by a rise in the temperature of the probe. .

According to a seventh aspect of the present invention, in the infrared detector, the infrared light receiving element is provided with a focal length f of the light collecting element.
A radius rs of the infrared light receiving element and an edge closest to the probe of the light-collecting element that has been moved to the maximum so as to contact 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 optical axis and the point where the straight line intersects with the surface of the tip of the probe, and the edge of the light-collecting element that has moved the most from the edge of the light-collecting element closest to the probe is the same as the edge of the light-collecting element with respect to the optical axis The distance Lα between the point where the straight line drawn so as to be in contact with the inner wall of the probe on the side of the probe intersects the surface of the probe tip and the light-collecting element; the radius r3 of the light-collecting element; Using the maximum movement distance d from the central axis of

[0039]

(Equation 5)

The distance L3 is set farther from the light-collecting element than the focal point of the light-collecting element.

As a result, since the light receiving area is limited and the infrared rays from the probe are condensed on points other than the light receiving element, it is possible to realize a structure capable of accurately detecting the temperature without being affected by a rise in the temperature of the probe. .

By using a refraction lens, a transmission type diffraction lens, a condensing mirror or a reflection type diffraction lens as a condensing element of the infrared detector, it is possible to realize a structure capable of accurately detecting a temperature.

According to a twelfth aspect of the present invention, there is provided the radiation thermometer, wherein the infrared detector, a temperature measuring element for detecting a temperature of the infrared detector, an output signal of the infrared detector, and an output signal of the temperature measuring element. A radiation thermometer comprising a signal processing means for calculating a body temperature from a display, a display means for displaying the calculated body temperature, and a main body containing the infrared detector.

As a result, the infrared light receiving element is not affected by the probe whose temperature has increased due to the heat of the ear canal, so that a radiation thermometer capable of accurately measuring the body temperature can be realized.

Since the infrared detector capable of measuring the temperature distribution is used, the temperature distribution inside the ear canal can be measured.

According to a thirteenth aspect of the present invention, the radiation thermometer calculates the body temperature a plurality of times while the infrared light receiving element is moving, and displays the maximum value as the body temperature.

Thus, the eardrum temperature showing the highest temperature in the ear canal including the eardrum and the ear canal can be accurately measured.

[0048]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows an infrared detector 11 according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 12 denotes an infrared light receiving element, and reference numeral 13 denotes a refraction lens which is a condensing element, which moves in a direction perpendicular to the optical axis. Light-collecting element 1
Numeral 3 is adapted to move within a range of a distance -d to d with respect to the central axis of the probe 15. Although not shown, the moving means is, for example, a moving means combining a motor and a gear. Reference numeral 14 denotes a light shielding member for preventing infrared light which does not pass through the light collecting element 13 from being incident on the infrared light receiving element 12. Reference numeral 15 denotes a probe for fixing and pointing the infrared detector 11 to an area to receive light in a concave portion such as the inside of a hole, and α denotes a light from the edge of the refractive lens 13 which has moved to the maximum (distance d) from the edge close to the probe 15. The point at which a straight line contacting the inner surface of the probe 15 on the same side with respect to the axis intersects the tip surface of the probe 15, α ′ is defined as the distance from the edge of the refractive lens 13 moved to the maximum in the opposite direction (distance −d) near the probe 15. The point at which a straight line that contacts the inner surface of the probe 15 on the same side with respect to the optical axis intersects the tip surface of the probe 15, F is the focal point of the refractive lens 13, Fα and Fα ′ are the image points of α and α ′ by the refractive lens 13, respectively, K1α Is an optical path of light (marginal ray) that travels from α to the Fα through the edge of the refraction lens 13 on the same side with respect to the optical axis, and K2α travels from α in parallel with the optical axis, passes through the focal point F, and passes through Fα. The optical path of the light reaching the 3α is an optical path of light that reaches Fα from α through the center of the refractive lens 13, and K4α is light that reaches Fα from α through the edge of the refractive lens 13 on the opposite side of the optical axis (marginal ray). K1α ′ is an optical path of light (marginal ray) traveling from α ′ to Fα ′ through the edge of the refractive lens 13 on the same side with respect to the optical axis, and K2α ′ is parallel to the optical axis from α ′. K3α ′ is the optical path of the light that reaches Fα ′ after passing through the center of the refractive lens 13 from K ′, and K4α ′ is the optical axis from α ′. Passes through the edge of the refractive lens 13 on the opposite side with respect to
Is the optical path of the light (marginal ray) reaching the optical path, and FX is the optical path K
This is the intersection between 1α and the central axis of the probe 15. The center axis of the probe 15 and the center axis of the infrared light receiving element 12 are aligned.

Here, an optical system designed to receive only infrared rays radiated from a concave portion such as an inner wall of a hole is designed.

The infrared light receiving element 12 is attached to the light shield 14 so that only the infrared light passing through the refractive lens 13 is received by the infrared light receiving element 12. The following design is performed after a configuration is adopted in which only infrared light that has passed through the refractive lens 13 is received.

In order to receive only the infrared ray from the object to be measured, it is sufficient that the infrared ray emitted from the probe 15 is not received. Therefore, a point located at the boundary between the region to receive light and the region not to receive light is imagined, and from this point, the light passes through the edge of the refractive lens 13 on the same side as the point located at the virtual boundary with respect to the optical axis. The probe 15 may be installed so as to be located farther from the optical axis than the optical path of the light (marginal ray). Therefore, the points located at the above-mentioned virtual boundary are defined as points α and α ′ where a straight line contacting from the edge of the refractive lens 13 to the inner surface of the probe 15 on the same side with respect to this edge and the optical axis intersects the tip surface of the probe 15. And Fα '
Infrared receiving element 12 inside the triangle formed by
Is installed. As a result, the probe 15 is located farther from the optical axis than the optical paths K1α and K1α ′ between α and the refractive lens 13, so that an optical system that does not receive light from the probe 15 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. 1, the light passing through the optical path K2α passes through the refraction lens 13, crosses the optical axis of the light-collecting element 13 at F, and reaches Fα while moving away from the optical axis. Similarly, the light passing through the optical path K1α passes through the refractive lens 13, crosses the optical axis, and reaches Fα while leaving the optical axis. The light passing through the optical path K3α crosses the optical axis by the refraction lens 13 and then reaches Fα while leaving the optical axis. Optical path K
The light passing through 4α crosses the optical axis and passes through the refraction lens 13, and after passing through the refraction lens 13, reaches Fα without crossing the optical axis. As described above, the position F.sub.F which is farther from the refraction lens 13 than the point FX where the optical path K1.alpha.
At a position closer to the refractive lens 13 than α, there is a region through which light emitted from α does not pass. Similarly, for α ′, light radiated from α ′ passes at a position farther from the refractive lens 13 than at the point where the optical path K1α ′ intersects with the optical axis and closer to the refractive lens 13 than Fα ′. There are areas that do not. By arranging the infrared light receiving element 12 inside the triangle formed by Fα, Fα ′, and FX, the infrared detector 11 that does not receive light emitted from α and α ′ can be obtained. Optical path K between α and refractive lens 13
Light from a portion farther from the optical axis than 1α is replaced with light from a point at a distance from the optical axis larger than α in the same plane as α. It is well known in geometrical optics that the intersection of this point with the refractive lens 13 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 15 will be received. Similarly, light from a portion farther from the optical axis than the optical path K1α 'between α' and the refractive lens 13 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 1 at this point
It is well known in geometrical optics that the intersection of 3 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 15 will be received. As described above, by disposing the infrared light receiving element 12 inside the triangle formed by Fα, Fα ′, and FX so as not to receive the infrared rays radiated from α and α ′, The configuration is such that the emitted infrared light is not received.

Hereinafter, the position of the infrared light receiving element 12 which does not receive the light from α will be obtained.

The infrared light receiving element 12 is closer to the refractive lens 13 than Fα. At this time, (Equation 1) and (Equation 2) hold.

LαF ≧ f + L3 (Equation 1) ∴L3 ≦ LαF-f (Equation 2) As shown in FIG. 1, the light receiving surface is located between the point where the optical path K1α intersects the optical axis and Fα. Therefore, of the light paths from α to Fα, the one closest to the infrared light receiving element 12 on the light receiving surface is K
1α. Therefore, in order to prevent the light from α from being received by the infrared light receiving element 12, it is necessary to satisfy (Equation 3). Here, rs is the radius of the infrared light receiving element 12.

Rαs1> rs ··· (Equation 3) Here, as is well known in geometrical optics, r3, rαF, rαS
1, L3, f and d satisfy (Equation 6) and (Equation 7) as geometric relationships.

[0058]

(Equation 6)

[0059]

(Equation 7)

(Equation 8) is obtained by substituting (Equation 7) into (Equation 3).

[0061]

(Equation 8)

From (Equation 2) and (Equation 8), the condition for not receiving the light emitted from α by the infrared light receiving element 12 is (Equation 9).

[0063]

(Equation 9)

Further, as is well known in geometrical optics, rα, L
α, L2, rαF, and LαF are expressed as
0) and (Equation 11) are satisfied.

[0065]

(Equation 10)

[0066]

[Equation 11]

By substituting (Equation 11) into (Equation 9), the condition for preventing the light radiated from α from being received by the infrared light receiving element 12 becomes (Equation 12).

[0068]

(Equation 12)

The equations (Equation 13) and (Equation 14) hold from Gauss's formula.

[0070]

(Equation 13)

[0071]

[Equation 14]

By substituting (Equation 14) for (Equation 12), the condition for not receiving the light emitted from α by the infrared light receiving element 12 is (Equation 15).

[0073]

(Equation 15)

As described above, in order to prevent the light radiated from α at the tip of the probe 1 from being received by the infrared light receiving element 12, the optics must satisfy (Equation 9), (Equation 12), or (Equation 15). The system needs to be designed. (Equation 9),
By disposing the infrared light receiving element 12 from the focal point of the refractive lens 13 by L3 given by (Equation 12) and (Equation 15), the infrared light radiated from the probe 15 is not received by the infrared light receiving element 12. Since only the radiated light from the measured object 3 can be received by the infrared light receiving element 12, a measurement error caused by a temperature change of the probe 15 can be prevented.

The light shield 14 and the probe 15 may be integrated.

Although the present embodiment has been described using an example in which the tip of the probe 15 is curved outward and the tip of the probe 15 is widened, as shown in FIG. The same applies to the case where the inner diameter is the narrowest. In this case, the points α and α ′ coincide with the points inside the tip of the probe 15, but the operation, operation, and effect are the same as those described with reference to FIG.

Next, the operation and action when the light-collecting element 13 is moved will be described with reference to FIG. When the light-collecting element 13 is at the position 13a, it means that infrared light emitted from the range C in the measured object is received. Also, the light-collecting element 1
When 3 moves to the position 13b, it means that infrared rays emitted from the range D in the measured object have been received. That is, by moving the light condensing element 13, the temperature of each of the objects 3 is measured at different positions. Therefore, the temperature distribution of the device under test 3 can be measured.

In this embodiment, the light-collecting element 13 has been described as being moved by a motor. However, the structure of the present invention is not limited to this.
A similar effect can be expected even if the structure is moved manually.

In this embodiment, an example is described in which the center axis of the probe 15 and the center axis of the infrared light receiving element 12 are aligned with each other. However, the present invention is not limited to this. If they are set within the range indicated by, the same effect can be obtained even if the two central axes do not coincide.

In this embodiment, an example in which the refraction lens 13 is used as the light-collecting element has been described. However, the same effect can be obtained by using a transmission type diffraction lens.

In the present invention, the example in which the refractive lens 13 is moved only in the direction perpendicular to the optical axis has been described, but the refractive lens 13 may be rotated. For example, the rotational movement is performed around the infrared light receiving element 12 as a center of rotation. At that time, the refraction lens 13 moves in a direction perpendicular to the optical axis and also moves parallel to the optical axis. At this time, the same effect can be obtained by disposing the infrared light receiving element 12 from the focal point by L3 given by (Equation 15), which derives the maximum moving distance in the vertical direction as d. If the rotational movement radius of the refraction lens 13 is sufficiently large, the parallel movement distance with respect to the optical axis becomes so small that it can be ignored.

(Embodiment 2) FIG. 4 shows an infrared detector 11 according to Embodiment 2 of the present invention. The difference from the first embodiment is that the point located on the virtual boundary is
A point α at which a straight line that contacts the inner surface of the probe 15 on the same side as the edge and the optical axis from the edge of
As α ′, the infrared light receiving element 12 is disposed in a region between the optical path K4α farther from the refractive lens 13 than Fα and the optical path K4α ′ farther from the refractive lens 13 than Fα ′.
This is the point that was installed. Thereby, the probe 15 is moved between the α and the refraction lens 13 in the optical paths K1α and K1α ′.
Therefore, an optical system that does not receive the light from the probe 15 can be 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 13, crosses the optical axis at F, reaches Fα, and moves away from the optical axis. Similarly, light passing through the optical path K1α passes through the refractive lens 13, 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 13, reaches Fα, and moves away from the optical axis. The light passing through the optical path K4α crosses the optical axis and passes through the refraction lens 13, and after passing through the refraction lens 13, reaches Fα without crossing the optical axis and thereafter 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 further from the refraction lens 13 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 13 than the image point Fα of α.
This portion of the optical path K farther from the refractive lens 13 than Fα
By installing the infrared light receiving element 12 in the region between 4α and the optical path K4α ′ farther from the refraction lens 13 than Fα ′, the infrared detector 11 that does not receive the infrared light radiated from α and α ′ is obtained. Can be α and refractive lens 1
The light from the portion farther from the optical axis than the optical path K1α during the period 3 is
It 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 intersection of this point with the refractive lens 13 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 15 will be received. Similarly, light from a portion farther from the optical axis than the optical path K1α 'between α' and the refractive lens 13 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 intersection of this point with the refractive lens 13 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 15 will be received. As described above, the region between the optical path K4α farther from the refractive lens 13 than Fα and the optical path K4α ′ farther from the refractive lens 13 than Fα ′, that is, the intersection of Fα, Fα ′, and K4α and K4α ′. Infrared light receiving element 1 inside triangle formed by FY
If the infrared rays emitted from α and α ′ are not received by installing 2, the configuration is such that the infrared rays emitted from the probe 15 are not automatically received.

Hereinafter, the position of the infrared light receiving element 12 which does not receive the light from α will be obtained.

The infrared light receiving element 12 is farther from the refractive lens 13 than Fα. At this time, (Equation 4) and (Equation 5) hold.

LαF ≦ f + L3 (Equation 4) L3 ≧ LαF-f (Equation 5) As shown in FIG. 3, the light receiving surface is more refracting lens 13 than Fα.
K4α is the light path closest to the infrared light receiving element 12 on the light receiving surface 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 12, (Equation 6) must be satisfied.

Rαs4> rs (Equation 6) Here, as is well known in geometrical optics, r3, rαF, LαF,
rαS4, L3, f and d are expressed as
6), (Equation 17) is satisfied.

[0088]

(Equation 16)

[0089]

[Equation 17]

By substituting (Equation 17) into (Equation 6), (Equation 18) is obtained.

[0091]

(Equation 18)

From (Equation 5) (Equation 18), the condition for not receiving the light radiated from α by the infrared light receiving element 12 is (Equation 19).

[0093]

[Equation 19]

Further, as is well known in geometrical optics, rα, L
α, L2, rαF, and LαF are expressed as
0) and (Equation 21) are satisfied.

[0095]

(Equation 20)

[0096]

(Equation 21)

By substituting (Equation 21) into (Equation 19), the condition for not receiving the light radiated from α by the infrared light receiving element 12 becomes (Equation 22).

[0098]

(Equation 22)

Further, (Equation 23) and (Equation 24) are established from Gauss's formula.

[0100]

(Equation 23)

[0101]

(Equation 24)

By substituting (Equation 24) for (Equation 22), the condition for not receiving the light radiated from α by the infrared light receiving element 12 is (Equation 25).

[0103]

(Equation 25)

As described above, in order to prevent the light radiated from α from being received by the infrared light receiving element 12, the optical system must satisfy the conditions of (Equation 19), (Equation 22), or (Equation 25). Need to design. (Equation 19), (Equation 2)
2) By disposing the infrared light receiving element 12 from the focal point of the refraction lens 13 by L3 given by (Equation 25), the infrared light emitted from the probe 15 is measured without being received by the infrared light receiving element 12. Since only the radiated light from the object 3 can be received by the infrared light receiving element 12, the temperature can be accurately detected without being affected by the temperature change of the probe 15, as in the first embodiment.

The light shield 14 and the probe 15 may be integrated.

Next, the operation when the light-collecting element 13 is moved will be described with reference to FIG. The difference from the first embodiment is that the infrared light receiving element 12 has Fα, Fα ′ and Fα.
(Equation 19) or (Equation 22) in the triangle formed by Y
Or it is set in the range of (Equation 25).

Thus, the temperature distribution of the DUT 3 can be measured as in the first embodiment.

In this embodiment, an example in which a refraction lens is used as the light-collecting element has been described. However, a similar effect can be obtained by using a transmission type diffraction lens.

(Embodiment 3) FIG. 6 shows an infrared detector 11 according to Embodiment 3 of the present invention. A different point from the first embodiment is that a condenser mirror 16 is used as a condenser element. With this configuration, it is possible to cause the infrared light receiving element 12 to receive only the radiated light from the measured object 3 without receiving the infrared light radiated from the probe 15 with the infrared light receiving element 12. Without receiving
Accurate temperature detection is possible.

Further, as shown in FIG. 7, a moving means (not shown) for the converging mirror 16 is provided.
Move to 16a and 16b, respectively, receive infrared rays at the positions of C and D of the DUT 3, respectively. Therefore, Example 1
And 2, the temperature distribution of the DUT 3 can be measured.

In the present embodiment, an example in which a refraction lens is used as the light-collecting element has been described. However, similar effects can be obtained by using a reflection type diffraction lens.

(Embodiment 4) FIG. 8 shows an infrared detector 11 according to Embodiment 4 of the present invention. The difference from the second embodiment is that a condenser mirror 16 is used as a condenser element. With this configuration, it is possible to cause the infrared light receiving element 12 to receive only the radiated light from the measured object 3 without receiving the infrared light emitted from the probe 15 with the infrared light receiving element 12. No accurate detection of temperature.

Further, as shown in FIG. 9, since a moving means (not shown) for the light-collecting element 16 is provided, the temperature distribution of the DUT 3 can be measured.

In this embodiment, an example in which a refraction lens is used as the light-collecting element has been described. However, a similar effect can be obtained by using a reflection type diffraction lens.

(Embodiment 5) An embodiment in which the infrared detector 11 described in Embodiments 1 to 4 of the present invention is applied to a radiation thermometer 17 will be described below. FIG. 10 shows an example in which the infrared detector 11 of the present invention, in particular, the infrared detector 11 using a condenser mirror 16 as a condenser element is applied to a radiation thermometer 17.

The radiation thermometer 17 includes the infrared detector 11
And a temperature measuring element 18 for detecting a temperature near the infrared detector 11, a probe 15, a signal processing means 19, and a display means 20. The infrared light receiving element 12 and the temperature measuring element 18 are provided with good thermal coupling via thermal grease. Further, the chopper 22 for interrupting the infrared light incident on the infrared light receiving element 12 is connected to the infrared light receiving element 1 of the infrared detector 11.
The motor 23 for driving the chopper 22 is disposed at an appropriate position. The condenser mirror 16 is connected to the second motor 24 so that the position can be moved in a direction perpendicular to the optical axis. The components having the same reference numerals as those of the first to fourth embodiments or the conventional example have the same structure, and the description of the same operation and action will be omitted.

When the body temperature is measured by the radiation thermometer 17 of the present invention, the infrared light receiving element 12 is continuously moved by the second motor 24 during the measurement, and the body temperature is calculated a plurality of times during the movement. And the thing which showed the highest value among the calculated body temperatures is displayed as a body temperature.

The infrared detector 11 of the present invention is used as the radiation thermometer 1
By applying the present invention to 7, the infrared light receiving element 12 can be configured not to receive the infrared light from the probe 15 whose temperature has increased due to contact with the ear canal 3a. In addition, since the highest temperature among the values measured in the ear canal a plurality of times is displayed, the temperature of the eardrum 3b having the highest temperature in the ear canal can be measured, and the body temperature can be displayed more accurately. It is. Therefore, it is possible to realize the radiation thermometer 17 capable of measuring the body temperature accurately without measurement error.

In this embodiment, the infrared light receiving element 1
Since a pyroelectric element was used as 2, means for interrupting infrared light such as a chopper 22 was required. However, when a thermopile was used as the infrared light receiving element 12, the motor 23 for driving the chopper 22 and the chopper 25 was not used. The infrared detector 11 and the radiation thermometer 17 having the same operation and effect can be configured.

[0120]

As described above, the infrared detector according to any one of the first to eleventh aspects of the present invention is capable of accurately detecting a temperature distribution without being affected by a probe whose temperature rises due to heat transmitted from an object to be measured. It is possible to realize an infrared detector capable of performing the above.

The radiation thermometer according to the twelfth aspect of the present invention has no measurement error because the infrared light receiving element is not affected by the temperature rise of the probe due to the heat transmitted from the ear canal.
Further, since an infrared detector capable of measuring the temperature distribution is used, the temperature distribution in the ear canal can be measured.

The radiation thermometer according to the thirteenth aspect of the present invention can realize accurate measurement of the eardrum temperature, that is, accurate measurement of the body temperature.

[Brief description of the drawings]

FIG. 1 is a configuration diagram and an optical path diagram of an infrared detector according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram and an optical path diagram of an infrared detector having a different configuration in the embodiment.

FIG. 3 is a configuration diagram and an optical path diagram of an infrared detector in the embodiment.

FIG. 4 is a configuration diagram and an optical path diagram of an infrared detector according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram and an optical path diagram of an infrared detector in the embodiment.

FIG. 6 is a configuration diagram and an optical path diagram of an infrared detector according to a third embodiment of the present invention.

FIG. 7 is a configuration diagram and an optical path diagram of an infrared detector in the embodiment.

FIG. 8 is a configuration diagram and an optical path diagram of an infrared detector according to a fourth embodiment of the present invention.

FIG. 9 is a configuration diagram and an optical path diagram of an infrared detector in the embodiment.

FIG. 10 is a configuration diagram of a radiation thermometer in Embodiment 5 of the present invention.

FIG. 11 is a configuration diagram of an infrared detector in a conventional example.

FIG. 12 is a configuration diagram of a radiation thermometer in a conventional example.

[Explanation of symbols]

 Reference Signs List 3 DUT 11 Infrared detector 12 Infrared light receiving element 13 Refractive lens (light collecting element) 14 Light shield 15 Probe 15a Opening 16 Light collecting mirror (light collecting element) 17 Radiation thermometer 19 Signal processing means 20 Display means 21 Main body case 24 Second motor (condenser moving means) α probe tip point α 'probe tip point F lens focus Fα image point by Fα lens Fα image point by Fα' lens f focal length of light collection element rs Radius of infrared light receiving element rα Distance between probe tip point and probe center Lα Distance between probe tip point and light collecting element r3 Light collecting element radius d Maximum movement distance of light collecting element from probe center L3 Focus and infrared light Light receiving element distance

Continued on the front page (72) Inventor Tadashi Miki 1006 Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 2G066 AC13 BA01 BA08 BA09 BA22 BA25 BA35 BA57 BC30

Claims (13)

[Claims] At least a light collecting element for collecting infrared light radiated from an object to be measured, an infrared light receiving element for receiving infrared light collected by the light collecting element, and the light collecting element from the object to be measured A cylindrical probe through which infrared light traveling
A light-shielding body that blocks infrared rays from outside the light-collecting element from being incident on the infrared light-receiving element, and limiting the light-receiving area by moving the infrared light-receiving element backward from the focal position of the light-collecting element; And an infrared detector having moving means for moving the light-collecting element at least in a direction perpendicular to the optical axis. 2. The method according to claim 1, further comprising: a cylindrical probe having a direction fixed to the object to be measured and having an opening through which infrared rays from the object to the light-collecting element pass, and wherein the infrared light receiving element is moved to the maximum. From the point where the 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 with respect to the optical axis from the edge of the light-collecting element closest to the probe intersects the surface of the tip of the probe. A point passing through the edge of the light-collecting element and intersecting the surface of the tip of the probe farther from the light-collecting element than an intersection of an optical path reaching an image point by the light-collecting element and a central axis of the probe. 2. The device according to claim 1, wherein a point intersecting with a surface of the tip of the probe is located in a region closer to the light collecting element than an image point by the light collecting element.
The infrared detector according to 1. 3. A straight line drawn from an edge closest to the probe of the light-collecting element that has moved as far as possible to contact 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 optical path from the point intersecting the front end surface of the probe to the image point by the light condensing element passing through the edge of the light condensing element and crossing the front end surface of the probe is the central axis of the probe. And an image point by the light-collecting element of a point intersecting with the surface of the probe tip and a symmetrical point of the image point with respect to the center axis of the probe. Claim 2.
Infrared detector as described. 4. An infrared light receiving element is arranged such that the focal length f of the light-collecting element, the radius rs of the infrared light-receiving element, and the optical axis from the edge closest to the probe of the light-collecting element that has moved as far as possible with respect to the optical axis. The distance rα between the center axis of the probe and a point 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 optical element and the center axis of the probe, A point where a straight line drawn from the edge closest to the probe 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 intersects the tip surface of the probe and the light-collecting element Using the distance Lα, the radius r3 of the light-collecting element, and the maximum moving distance d of the light-collecting element from the center axis of the probe, 4. The infrared detector according to claim 3, wherein the light detecting element is disposed farther from the light collecting element than the focal point of the light collecting element by L3 given by: 5. A straight line drawn from the edge closest to the probe of the light-collecting element that has moved as far as possible so as to contact the inner wall of the probe on the same side of the optical axis as the edge of the light-collecting element. The infrared detector according to claim 1, wherein the infrared detector is located at a position farther from the light-collecting element than an image point of the light-collecting element at a point intersecting with a surface of the tip of the probe. 6. A straight line drawn from the edge closest to the probe of the light-collecting element that has moved as far as possible to contact the inner wall of the probe on the same side of the optical axis as the edge of the light-collecting element. From the point intersecting the front end surface of the probe to the image point by the light condensing element at the point intersecting the front end surface of the probe passing through the opposite edge across the optical axis of the light condensing element. A point where the reaching optical path intersects the center axis of the probe, an image point of the intersection point with the surface of the probe tip by the light-collecting element, and a symmetrical point of the image point with respect to the center axis of the infrared light receiving element. The infrared detector according to claim 5, wherein the infrared detector is installed inside a triangle formed. 7. The infrared light receiving element is arranged such that the focal length f of the light-collecting element, the radius rs of the infrared light-receiving element, and the optical axis from the edge closest to the probe of the light-collecting element that has been moved to the maximum. The distance rα between the point at which the straight line drawn so as to contact the inner wall of the probe on the same side as the edge of the optical element intersects the surface of the tip of the probe and the center axis of the probe, The distance between the point where a straight line drawn from the edge closest to the probe and 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 intersects the surface of the probe tip and the light-collecting element Using Lα, the radius r3 of the light-collecting element, and the maximum moving distance d of the light-collecting element from the central axis of the probe, 7. The infrared detector according to claim 6, wherein the light detector is disposed farther from the light-collecting element than the focal point of the light-collecting element by L3 represented by: 8. The infrared detector according to claim 1, wherein the light-collecting element is a refractive lens. 9. The infrared detector according to claim 1, wherein the light-collecting element is a transmission type diffraction lens. 10. The infrared detector according to claim 1, wherein the light-collecting element is a light-collecting mirror. 11. The infrared detector according to claim 1, wherein the light-collecting element is a reflective diffraction lens. 12. The infrared detector according to claim 1, a temperature measuring element for detecting a temperature of the infrared detector, an output signal of the infrared detector, and an output signal of the temperature measuring element. A radiation thermometer comprising: signal processing means for calculating a body temperature from a display; display means for displaying the calculated body temperature; and a main body containing the infrared detector. 13. The radiation thermometer according to claim 12, wherein the body temperature is calculated a plurality of times while the infrared light receiving element is moving, and the maximum value is displayed as the body temperature.