JP2813331B2 - Radiation thermometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation thermometer, and more particularly to a radiation thermometer system that does not use a preheating device in a main body.

[0002]

2. Description of the Related Art As a thermometer, for example, a pen-type electronic thermometer instead of a glass thermometer has recently become widespread.

The characteristics of this electronic thermometer are that it is not broken, it is easy to read, and there is a buzzer for terminating the temperature measurement. However, the time required for the temperature measurement is about 5 to 10 minutes, which is almost the same as a glass thermometer. This is the reason that the temperature measurement is troublesome. This has a problem in the method of inserting the sensor part into the armpit or in the mouth and bringing it into contact with the measurement site for measurement. There are two reasons why the measurement time is long.

[0004] First, the skin temperature of the armpit and the mucous membrane temperature in the mouth are lower than the body temperature before the start of the temperature measurement, and the body temperature gradually approaches the body temperature by closing the armpit and the mouth.

Second, the thermometer sensor section is cooled to the ambient temperature, and when inserted into the measurement site, the temperature of the measurement site is further reduced, and it takes more time to equilibrate to the original body temperature.

This state will be described with reference to FIG.

FIG. 14 is a temperature measurement curve of a contact-type electronic thermometer with the horizontal axis representing the temperature measurement time and the vertical axis representing the measurement temperature, H being the temperature curve of the armpit as a measurement site, and M being the measurement temperature curve of the thermometer. is there.

That is, at the time t ₁ at the start of the temperature measurement, the underarm skin temperature is 36 ° C. or less, and the temperature of the thermometer sensor section is also cooled to 30 ° C. or less. When the thermometer sensor section is inserted into the armpit from this state and the armpit is closed, the measured temperature M of the thermometer sensor section rapidly rises, but the temperature H of the armpit is cooled by the thermometer sensor section until t _2. After processing, begin to rise to true body temperature. When the sensor of the thermometer is warmed to the temperature of the armpit skin, the point t
_{From 3 on} , the two temperature curves H and M rise in unison, but it takes about 5 to 10 minutes to rise to the true body temperature as described above.

As is well known, an actual body temperature measuring method measures at a fixed interval from the time t ₁ , compares the measured values and sequentially stores the maximum value,
Determining the difference between the measured value, when the difference between the measured value is smaller than a predetermined value, and at the same time to stop the temperature measuring at the point t _4, the operator displays the maximum value at that time as the body temperature (For example, JP-A-50-31888).

Considering the conditions for performing the body temperature measurement in a short time in consideration of the first and second reasons, a site where the body temperature has been attained before the start of the temperature measurement is selected, and the temperature of the cooled sensor is selected. If the measurement can be performed without contacting the sample, the measurement can be performed in a short time.

In view of this, a radiation thermometer has been proposed in which the eardrum is selected as a site having a body temperature before the start of the temperature measurement, and the temperature of the site is measured in a non-contact manner (for example, Japanese Unexamined Patent Publication No. Sho 6 (1994)).
1-1117422).

Next, the principle of the radiation thermometer which is the basis of the radiation thermometer will be described. "All objects are
The surface emits infrared radiation, and the amount and spectral characteristics of the infrared radiation energy are determined by the absolute temperature of the object, and also depend on the properties of the object and the finished surface condition. ] This is based on the laws of physics. The rule indicating this will be described.

First, Planck's law expresses the relationship among the radiation intensity, spectral distribution, and temperature of a black body.

[0014]

(Equation 1) FIG. 15 illustrates Planck's law. It can be seen that the radiant energy increases as the temperature of the blackbody increases. Further, the radiant energy changes depending on the wavelength, and the peak value of the distribution shifts to the short wavelength side as the temperature increases, but it can be seen that the radiant energy is radiated over a wide wavelength band.

The total energy emitted from the black body is expressed as follows: W (λ, T) given by equation (1) is expressed as follows.
It is obtained by integrating up to ∞. This is Stefan-Boltzmann's law.

[0016]

(Equation 2) As is apparent from the equation (2), the total radiation energy W ₁ is proportional to the fourth power of the absolute temperature T of the black body light source. Also,
It should also be noted that equation (2) is an equation obtained by integrating infrared radiation emitted from a black body for all wavelengths.

All the above rules are derived for a black body having an emissivity of 1.00. However, in practice most objects are not perfect radiators and the emissivity of the objects is 1.00
Less than. Therefore, it is necessary to correct by multiplying the emissivity. Thus, the radiant energy W ₂ of most objects that are not black bodies can be expressed as in equation (3).

[0018]

(Equation 3) Equation (3) represents the infrared radiation energy emitted from the object and incident on the infrared sensor. The infrared sensor itself emits infrared radiation according to the same rule. Therefore, if the temperature of the infrared sensor itself and T _0, results in that the infrared radiant energy of oT ₀ ^4, the energy W obtained by subtracting the radiation from the entrance is (4).

[0019] ^{W = σ (εT 4 + γT} 0 4 -T 0 4) ... (4) Ta: Ambient temperature of the object gamma: Since the transmittance of the reflectance measured object of an object can be regarded as zero γ = 1-ε is Holds.

In equation (4), it is assumed that the infrared sensor is ideally manufactured and the emissivity of the infrared sensor is 1.00.

If the infrared sensor has been left in the environment of the ambient temperature Ta for a long time, and the infrared sensor temperature T ₀ is equal to the ambient temperature Ta, the equation (4) becomes the following equation (5). become.

[0022] ^{W = σ (εT 4 + γT} 0 4 -T 0 4) = εσ (T 4 -T 0 4) ... (5) Figure 18 is a basic configuration diagram of a conventional radiation thermometer, based on the following figures The configuration will be described.

The radiation thermometer 7 comprises an optical system 2, a detection unit 3, an amplification unit 4, an operation unit 5, and a display device 6.

The optical system 2 comprises a light guiding means 2a for efficiently condensing infrared radiation from the measured object L and a filter 2b having a transmission wavelength characteristic. As the light guide means 2a, a cylinder whose inner surface is gold-plated is used. Filter 2
For b, a silicon filter is used.

The detecting section 3 comprises an infrared sensor 3a and a temperature sensor 3b. The infrared sensor 3a converts infrared radiation energy obtained by subtracting radiation from the infrared sensor 3a itself from incident infrared radiation energy or the like condensed by the optical system 2 into an electric signal, that is, an infrared voltage Vs. Further, the temperature sensor 3b is disposed near the infrared sensor 3a to measure the temperature T ₀ of the infrared sensor 3a and the temperature near the infrared sensor 3a, and outputs a temperature-sensitive voltage Vt. A thermopile is used for the infrared sensor 3a, and a temperature-sensitive diode such as a thermistor is used for the temperature-sensitive sensor 3b.

The amplifier 4 includes an infrared sensor 3a, that is, an amplifier circuit for amplifying an infrared voltage Vs output from the thermopile, and an A / A converter for converting the output voltage of the amplifier circuit into digitized infrared data Vd. An infrared amplifier 4a composed of a D conversion circuit, an amplifier circuit for amplifying the temperature sensor 3b, that is, a temperature sensing voltage Vt which is a forward voltage of the temperature sensing diode, and an output voltage of the amplifier circuit being digitized. It consists configured thermosensitive amplifier 4b by the a / D converter circuit for converting the temperature-sensitive data T ₀ has.

The two signals V from the amplifier 4
d and T ₀ are converted into temperature data T by the arithmetic unit 5 and displayed on the display device 6. Here, the calculating unit 5 is configured to set an emissivity ε of the measured object L by using an emissivity input unit 5a.
And an arithmetic circuit 5c for performing an arithmetic operation based on the equation (5).

With the above arrangement, the temperature of the object to be measured L can be measured by the non-contact method. How it operates will be described.

First, the measured object L emits infrared light,
The wavelength spectrum distribution covers a wide wavelength range as shown in FIG. Then, the infrared radiation is transmitted to the light guide 2a.
And passes through the filter 2b having a transmission wavelength characteristic to reach the infrared sensor 3a.

There is another infrared radiation energy that reaches the infrared sensor 3a. One is that infrared radiation is emitted from an object around the measured object L, which is
Is the infrared radiant energy transmitted through the filter 2b after being reflected by In addition, infrared radiation is emitted from the infrared sensor 3a or an object around the infrared sensor 3a, and the infrared radiation is reflected by the filter 2b. is there.

The infrared radiation energy from the infrared sensor 3a can be expressed by the following equation (3). Where ε =
1.00. That is, measuring the temperature of the infrared sensor 3a itself indirectly measures the infrared radiation energy from the infrared sensor 3a. Therefore, the temperature sensor 3b is disposed near the infrared sensor 3a,
a and its surrounding temperature T ₀ are measured.

Then, the infrared sensor 3a converts the infrared radiation energy W obtained by subtracting the infrared radiation energy radiated from the incident infrared radiation energy into an electric signal. Infrared sensor 3
Since a is a thermopile, an infrared voltage Vs proportional to the infrared radiation energy W is output.

Here, the infrared voltage Vs, which is the output voltage of the infrared sensor 3a, is equal to the infrared radiation energy W per unit area.
And the light receiving area S of the infrared sensor 3a multiplied by the sensitivity R. The infrared data Vd, which is the output voltage of the infrared amplifier 4a, is obtained by multiplying the infrared voltage Vs of the infrared sensor 3a by the amplification factor A of the infrared amplifier 4a.

Vs = R · W · S Vd = A · Vs Since the above relation holds, the equation (5) can be expressed as the equation (6).

Vd = ε · σSRA (T ⁴ −T ₀ ⁴ ) (6) Vd: output voltage of infrared amplifier 4 a S: light receiving area of infrared sensor 3 a R: sensitivity of infrared sensor A: infrared amplifier In general, the equation (6) is arranged with K ₁ = σSRA, and the temperature T of the measured object L is calculated based on the equation (7).

[0036]

(Equation 4) However, the thermal infrared sensor used in the conventional radiation thermometer itself has no wavelength dependency, but a silicon filter or a quartz filter is used as a window material in front of the can package in which the infrared sensor is mounted. And the like. This is because the infrared radiation from the object has a wavelength spectrum distribution as shown in FIG. 15, so that only the radiating wavelength band is mainly transmitted and the influence of external light is reduced. is there. Each of the transmission materials has a specific transmission wavelength characteristic, and an appropriate transmission material is selected according to the temperature of the measured object, the workability of the transmission material, the price of the material, and the like.

FIG. 16 shows the transmittance of a silicon filter which is one of the transmission materials. It can be seen that the silicon filter shown in FIG. 16 transmits only the wavelength band of about 1 to 18 [μm]. And its transmittance is about 54%.

As described above, the filter-equipped infrared sensor itself is of a thermal type and has no wavelength dependence, but has a wavelength dependence of transmitting only a specific wavelength band by the filter as a window material.

Therefore, equation (5) obtained by integrating the infrared radiation energy input to the infrared sensor with a filter over all wavelengths holds true for an infrared sensor with a filter that transmits only a specific wavelength band. There will be no
As a result, the error is included.

Further, in the conventional configuration, the sensitivity R of the infrared sensor is treated as a constant, but the actual sensitivity R of the infrared sensor fluctuates depending on the infrared sensor temperature T _0. The state is shown in FIG.

That is, FIG. 19 shows the sensitivity R obtained by actually measuring the output voltage Vs of a thermopile used as an infrared sensor using a black body, and changing the infrared sensor temperature T ₀ to obtain the sensitivity R at each temperature. It is a plot of the change in R. As a result, it has been found that the temperature dependence of the sensitivity R can be approximated on a straight line as shown in equation (8).

R = α {1 + β (T ₀ −T _m )} (8) Here, α is a sensitivity R serving as a reference when T ₀ = T _m . _Tm is a representative temperature of the infrared sensor temperature, for example,
This is the temperature of the infrared sensor when measuring the sensitivity of the infrared sensor at the factory. β represents the degree of fluctuation, and 1 [deg]
The fluctuation rate per unit was -0.3 [% / deg].

It is natural that the fluctuation of the sensitivity R as described above causes an error.

The above-mentioned fluctuation rate β depends on the manufacturing conditions of the thermopile, and can be reduced by increasing the purity and processing accuracy. However, in the case of a commercially available thermopile considering mass productivity, The above values are obtained.

However, ordinary radiation thermometers are intended to measure high temperatures, and the measurement range is 0 to 300.
Since the measurement accuracy is about ± ° C. and the measurement accuracy is about ± (2 to 3) ° C., the error due to the filter characteristics and the fluctuation of the sensitivity of the infrared sensor is negligible, and the countermeasures are omitted.

Considering the measurement conditions as a thermometer, the temperature measurement range may be as narrow as about 33 ° C. to 43 ° C., but ± 0.1 ° C. is required as the temperature measurement accuracy.

Therefore, when the radiation thermometer is used as, for example, a thermometer, it is necessary to improve the accuracy of temperature measurement by taking some measures against errors due to the filter characteristics and the fluctuation of the sensitivity of the infrared sensor.

As a countermeasure against this, Japanese Patent Laid-Open Publication No.
The radiation thermometer disclosed in Japanese Patent Publication No. 22 has the following method.

That is, the probe unit has an infrared sensor, a chopper unit having a target, and a charging unit.

A heating control means for preheating the infrared sensor and the target to a reference temperature (36.5 ° C.) of the external ear canal is provided, and the heating control means is driven by charging energy from the charging unit. I have.

At the time of measuring the body temperature, the probe unit is set on the chopper unit, and the probe having the infrared sensor and the target are calibrated by preheating the probe and the target by the heating control means. Body temperature is measured by detecting the infrared radiation emitted from the eardrum by inserting it into the ear canal and comparing it with the infrared radiation emitted from the target.

Next, the reason why the accuracy of temperature detection is improved by the above method will be described.

This method eliminates various error factors by preheating a probe having an infrared sensor and a target to a reference temperature (36.5 ° C.) close to normal body temperature by a heating control means. .

That is, by heating the probe to a reference temperature higher than room temperature, the infrared sensor is kept at a constant temperature irrespective of the ambient temperature, so that the sensitivity of the infrared sensor does not fluctuate, and the error can be ignored. Further, after performing calibration with the body temperature to be measured and the reference temperature of the target being close to each other, a comparative measurement is performed, so that the error due to the filter characteristics and the like can be ignored.

Furthermore, since the probe is preheated to a temperature close to the body temperature, when a conventional cold probe is inserted into the ear canal, the temperature of the ear canal and the eardrum is lowered by the probe, and correct body temperature measurement is not performed. The problem has also been solved.

[0056]

However, Japanese Patent Application Laid-Open No.
The radiation thermometer disclosed in 1-1117422 is extremely excellent in the accuracy of temperature measurement, but on the other hand, requires a heating control device with high control accuracy, so that its structure and circuit configuration become complicated and cost increases. Problem. In addition, a long stabilization time was required to preheat the probe and the target and control them at a constant temperature. Furthermore, since the energy for driving the heating control device is relatively large power, a large-sized charging unit having a power cord is required. Therefore, a portable thermometer using a small battery as an energy source includes: It can be said that it is impossible to adopt this method.

An object of the present invention is to solve the above-mentioned problems and to provide a radiation thermometer which is portable and miniaturized at low cost while maintaining the accuracy of temperature measurement as a thermometer.

[0058]

The gist of the present invention to achieve the above object is as follows.

That is, according to the present invention, the light guide means for condensing the heat radiation from the object to be measured, and the infrared light for receiving the heat radiation condensed through the light guide means and outputting an electric signal. A sensor, a temperature-sensitive sensor that measures an absolute temperature serving as a reference, and outputs an electric signal, the infrared sensor, and infrared data and temperature data digitized based on the electric signal from the temperature sensor. Signal processing means for outputting temperature data; temperature calculating means for calculating temperature data of the object to be measured based on the infrared data and temperature-sensitive data; and light guiding means for the infrared sensor.
Detects the comparison infrared data being directed to a reference comparison plane of reflective plate positioned on the distal end side of this comparative red
Judgment that the value of outside data is zero or minute and compare
A comparison detection circuit having a zero detection circuit that outputs an output signal ;
Display temperature according to the temperature data and detect zero
The measurement is turned on by the comparison detection signal output from the circuit.
A display device provided with a fixed permission mark, and a radiation thermometer based on comparison infrared data obtained by measuring the temperature of the reference comparison surface.
There is an irregular heat balance between the light guide means and the infrared sensor.
Temperature until the heat balance reaches the desired state of equilibrium.
The measurement is suspended .

Therefore, according to the present invention, even when the heat balance is irregular between the light guide means and the infrared sensor, this can be detected as comparative infrared data,
Using the comparative infrared data, the temperature measurement is suspended until the thermal balance reaches a desired equilibrium state, or the comparative infrared data is used for various temperature measurement processes, such as using the comparative infrared data for calculating temperature data. It becomes possible. As a result,
ADVANTAGE OF THE INVENTION According to this invention, the temperature detection accuracy of a radiation thermometer can be maintained suitably.

[0061]

[0062] Further, according to the present invention, it is possible to determine the state of the heat balance by the presence or absence of comparative infrared data,
When the heat balance is within the predetermined region, accurate temperature measurement can be reliably performed.

Further , according to the present invention, the temperature is measured by the display circuit.
There is an advantage that it is possible to easily recognize the possibility .

Further , according to the present invention, since the reference comparison surface for detecting the comparative infrared data is provided on the tip side of the light guide means of the radiation thermometer, the detection of the comparative infrared data is extremely easy. There is a point.

Further, according to the present invention, the light guide means is located on the tip side .
The reflecting plate is provided in a case that houses the radiation thermometer.

Therefore, according to the present invention, it is possible to detect the comparative infrared data while the thermometer itself is housed in the case when performing the temperature measurement by the radiation thermometer.

[0067]

[0068]

[0069]

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

(Basic Example) FIG. 11 is a block diagram showing a basic configuration of a radiation thermometer according to the present invention. In this basic example, a thermopile having good manufacturing conditions is used to obtain a sensitivity R. This is a basic example in which the fluctuation is negligible and the filter characteristics are corrected.

In FIG. 11, the same numbers as those in FIG. 18 indicate the same components, and a description thereof will be omitted. 18 is different from FIG. 18 in that the temperature of the eardrum of the ear as the object L to be measured is measured and the arithmetic unit 5 is described below.

The operation unit 5 of the radiation thermometer 70 includes emissivity input means 5a for setting the emissivity ε of the measured object L,
It comprises a filter correction means 5b for setting information on the transmission wavelength characteristic of the filter 2b, and a temperature calculation circuit 5c.

Therefore, the calculating section 5 calculates the measured temperature Tb based on the emissivity set value from the emissivity input means 5a and the filter correction value from the filter correction means 5b.

First, a description will be given of a temperature calculation formula in consideration of the wavelength dependence of the filter-equipped infrared sensor according to this basic example.

As described above, the infrared sensor 3a converts the infrared radiation energy W obtained by subtracting the radiation from the incident light into the infrared voltage Vs. The energy W is represented by the following equation (9).

[0076]

(Equation 5) The first term of the equation (9) is the energy radiated from the measured object L having the emissivity ε and transmitted through the filter.
The second term is the energy radiated from the surrounding object at the temperature T ₀ by infrared radiation, reflected by the measured object L, and transmitted through the filter 2b. The third term is infrared radiation from the infrared sensor 3a at the temperature T ₀ or an object around the infrared sensor 3a, and the filter 2b
Or the energy reached by infrared radiation from the filter 2b at the temperature T ₀ . Here, there is a relationship that "the sum of the transmittance, the reflectance, and the emissivity of the transmissive material is equal to 1." The third term is a term in which reflection or radiation by the filter 2b is considered. It should also be noted that this reflection reflects infrared radiation from the infrared sensor 3a side by the filter 2b. Finally, the fourth term is the energy radiated from the infrared sensor 3a itself at the temperature T ₀ , and the negative sign is negative.

Equation (9) can be rewritten as equation (10).

[0078]

(Equation 6) That is, the infrared radiation energy W obtained by subtracting radiation from the incidence of the infrared sensor 3a having the filter 2b is "proportional to the difference of the absolute temperature to the fourth power as shown in the equation (5). ], But it must be an expression that takes into account the transmission wavelength characteristic of the filter 2b as in Expression (10). In other words, a new equation is required instead of the Stefan-Boltzmann law shown in equation (2).

Then, assuming that the infrared radiation energy radiated from the black body at the absolute temperature T and transmitted through the filter having the transmittance η (λ) is F (T), it can be expressed as in equation (11).

[0080]

(Equation 7) Here, the temperature range of the absolute temperature T is from Tmin to Tmax.
And any absolute temperature T ₁ in that section,
Table 1 summarizes the calculation results of the equation (11) for T ₂ , T _3, ..., T _n .

[0081]

[Table 1] Then, it was examined how the relationship between the absolute temperature T shown in Table 1 and the infrared radiation energy F (T) transmitted through the filter relates to Stefan-Boltzmann's law. FIG. 17 is a graph showing the examination process. This will be described with reference to FIG.

The horizontal axis of the graph is absolute temperature, the unit is [K], and the vertical axis is radiant energy, the unit is [W / cm ² ]. Curve A in FIG. 17 is a characteristic curve of Expression (2) showing Stefan-Boltzmann's law, and curve B is a characteristic curve of the present basic example in consideration of the filter characteristics.

The curve B represents the absolute temperatures T ₁ to T ₁ shown in Table 1.
Blot each point at T _n to create a curve B ′,
The curve A is deformed and moved and superimposed on the curve B '. The type of the deformation and movement is determined by the coefficient a of the fourth-order term of the curve A, the moving amount b in the horizontal axis direction, and the vertical axis direction. By selecting the moving amount c of the above, it becomes possible to superimpose.

From the results, the above equation (11) was approximated to the equation (12) using the three types of set values a, b, and c.

F (T) = a · (T−b) ⁴ + c (12) From the values shown in Table 1, a
The optimal values of b and c are obtained by a method such as the least square method,
Substituting this value into equation (12) gives an approximate equation.

Here, for a, b, and c, Stephan
This will be described in comparison with Boltzmann's law (2).

A is the coefficient of the fourth order of the absolute temperature T, which corresponds to the Stefan-Boltzmann constant σ of the curve A, the unit is [W / cm ² · deg ⁴ ], and b is the symmetry axis temperature. In the curve A, the absolute temperature is 0 [K], whereas in the curve B, the absolute temperature b [K] is set as the axis of symmetry.

C indicates a minimum value. In the curve A, 0 [W / cm ² ], but in the curve B, C [W / cm ² ].
cm ² ] as the offset.

Then, using the approximate expression (12), (1
Rewriting equation (0) gives equation (13).

W = ε [a · (T−b) ⁴ + c] −ε [a · (T ₀ −b) ⁴ + c] = ε · a [(T−b) ⁴ − (T ₀ −b) ⁴ (13) As can be seen from the above equation (13), the minimum value c is canceled.

Here, the infrared data Vd based on the infrared light radiated from the eardrum is given by K ₂ = aSRA according to the light receiving area S of the infrared sensor 3a, the sensitivity R, and the amplification factor A of the infrared amplifier 4a (13) The equation becomes the equation (14), and the body temperature Tb of the eardrum is calculated by the equation (15) based on the equation (14).

[0092]

(Equation 8) That is, when a filter having a transmission wavelength characteristic is used for an optical system member, “the infrared radiation energy is equal to the absolute temperature T.
Is proportional to the fourth power of. Instead of using the rule "", the infrared radiation energy is required to be calculated based on the equation (14), "The infrared radiation energy is proportional to the fourth power of (absolute temperature T-symmetric axis temperature b)." is there.

From this result, the symmetric axis temperature b is output from the filter correction means 5b shown in FIG. 11, and the arithmetic circuit 5c calculates the body temperature Tb of the measured object L, that is, the eardrum, based on the equation (15). .

Next, an approximate expression considering a silicon filter actually used as the filter 2b will be described.

FIG. 16 shows the transmission wavelength characteristics of the silicon filter.
However, in order to simplify the calculation, "the transmission wavelength band of the silicon filter is 1 to 18 [μm], and its transmittance is 54 [%]. ].

[0096]

(Equation 9) W (λ, T) is calculated by substituting equation (1).

Since the measurement environment and the measurement temperature range of the object to be measured are within the range of 0 ° C. to 50 ° C.,
Tmin was 273 [K] and Tmax was 323 [K]. Table 2 shows the calculation results of equation (16).

From the data shown in Table 2, a, b, and c when approximated by the equation (12) are obtained by the least square method.

A = 4.104 × 10 ⁻¹² [W / cm ² · deg ⁴ ] b = 45.96 [K] c = −6.144 × 10 ⁻⁴ [W / cm ² ] That is, it is determined here. The fourth-order term coefficient a and symmetry axis temperature b
Is a value indicating the transmission wavelength characteristic of the silicon filter, and the value of the coefficient a and the symmetry axis temperature b of the fourth order is output from the filter correction means 5b. The filter correction means 5b is a part of the operation program memory of the operation unit 5, in which the coefficient a of the fourth-order term and the symmetric axis temperature b are written.

[0100]

[Table 2] That is, when the silicon filter is used as a window material for measurement of the infrared sensor, when calculating the temperature T of the object to be measured, instead of using the equation (5),
By performing the calculation using the expression (14), a highly accurate temperature calculation can be performed.

As is clear from the above description, according to this basic example, even if a transmission material having transmission wavelength characteristics is used as the window material of the infrared sensor, the temperature of the object to be measured can be measured with high accuracy. Can be.

Also, in the case of changing the material of the transmission material which is the window material of the infrared sensor, the temperature can be measured with high accuracy by rewriting the value of the filter correction means 5b which is a part of the program memory.

In this basic example, as a new equation replacing the Stefan-Boltzmann's law, 4
Although the approximation formula of the following term was adopted, as shown in FIG. 17, the thermometer uses only a part of the curve as the measurement range such as Tmin to Tmax, so that the approximation of the fourth term is not necessarily required. Even if it is approximated, sufficient accuracy as a thermometer can be obtained. For example, the expression (14) ′ can be adopted as an approximate expression of the quadratic term.

Vd = εK ′ ₂ ｛(Tb−b ′) ² − (T ₀ −b ′) ² … (14) ′ (First Embodiment) Next, as a first embodiment of the present invention, mass production is performed. A specific configuration of a radiation thermometer actually manufactured using a commercially available thermopile considering the above will be described. In practice, the radiation thermometer of the present embodiment is used as a thermometer.

FIGS. 2 and 3 are a rear view and a side view of the radiation thermometer according to the present embodiment. Reference numeral 1 denotes a radiation thermometer, which includes a main body 10 and a head 11, a display device 6 for displaying temperature on the back of the main body 10, a check button 12 having a push button structure on the front, and a side surface. Are provided with a power switch 13 having a slide structure and measure buttons 14 and 15 having a push button structure.

The head portion 11 is provided so as to protrude from the end portion of the main body portion 10 in a "L" shape, and the tip of the head portion 11 is a probe 16.
Reference numeral 6 denotes a light guiding means including the optical system 2 shown in FIG.

That is, this optical system is provided with a light guiding means for condensing infrared radiation from an object to be measured and a filter having a transmission wavelength characteristic.

The operation method of the radiation thermometer 1 is as follows. A check operation to be described later is performed in a state where the power switch 13 is turned on, and after that, while the probe 16 is inserted into the outer ear hole of the subject, the measurement button 14 is operated. , 15 are turned on, the temperature measurement is instantly completed, and the result is displayed on the display device 6 as the temperature.

FIG. 4 is a sectional view of the head section 11.
The case bodies 17 and 18 are formed of a resin molded body having extremely low thermal conductivity. And the probe 1 of the case body 17
The portion forming 6 is a cylindrical tubular portion 17a, and a metal housing 19 made of a lightweight and highly heat-conductive metal such as aluminum is fitted into the tubular portion 17a. The metal housing 19 has a cylindrical portion 19a, a hollow portion 19b communicating with the cylindrical portion 19a, and a concave portion 19c for embedding a temperature sensing element.
And a base portion 19d provided with
At the end of 9a, a step 19e for mounting a filter is provided. The cylindrical portion 19a is fitted with a light guide tube 20 in which the inner periphery of a brass (Bu) pipe is plated with gold (Au), and the step 19e at the tip has a selective passage of infrared rays and a dustproof function. The hard cap 21 is fixed. Further, a thermopile as the infrared sensor 3a is buried in the hollow portion 19b of the base 19d, and the temperature sensor 3b is buried in the concave portion 19c by sealing resins 22 and 23, respectively.

The infrared sensor 3a and the temperature sensor 3b are connected to the wiring pattern of the circuit board 26 by lead wires 24 and 25, respectively, and are led to an amplifier circuit described later.

According to the above configuration, since the infrared sensor 3a, the light guide tube 20, and the hard cap 21 are connected by the metal housing 19 having good heat conductivity, a thermal balance is always obtained, and the common use is achieved. The temperature is detected by the temperature sensor 3b.

A temperature detecting cover 28 is detachably attached to the probe 16 and is made of a resin having poor heat conductivity. The tip 28a is made of a material which allows infrared rays to pass therethrough.

FIG. 5 is an enlarged cross-sectional view of the tip of the probe 16. The tip 28a of the temperature detecting cover 28 covers the tip of the probe 16 to prevent the probe 16 from contacting the inner wall of the outer ear hole. doing.

FIG. 6 shows the radiation thermometer 1 in a storage case 30.
FIG. 4 is a side view showing a state where the main body 10 is mounted on the storage case 30. The storage case 30 includes a mounting portion 30a for mounting the main body 10 and a storage portion 30b for storing the probe 16.
At a position corresponding to the tip of the probe 16 on the bottom surface 30c of the storage portion 30b, a reflection plate 31 forming a reference comparison surface in the present invention is fixed.

[0115] Further, the storage case 30 is provided with a button pressure portion 30d at a position corresponding to the check button 12. When the radiation thermometer 1 is set in the storage case 30 as shown in FIG. 6 with the power switch 13 turned on, the tip of the probe 16 is set on the reflection plate 31 and the check button is pressed by the button pressure unit 30d. 12 turns ON. This state is a function check state to be described later, and it is possible to know from the display state of the display device 6 whether or not temperature measurement is possible.

FIG. 7 is a sectional view of an ear showing a state in which temperature is being measured by the radiation thermometer 1, wherein 40 is an auricle, 41 is an ear canal, 42 is an eardrum, and Numerous hairs 43 grow on the inner wall. Further, earwax 44 may accumulate on the inner wall of the outer ear hole 41.

As shown, the probe 16 of the radiation thermometer 1
Is inserted into the external ear hole 41, and the temperature can be measured instantaneously by pressing the measure buttons 14 and 15 with the distal end directed toward the eardrum 42.

FIG. 1 is a block diagram of the radiation thermometer 1 shown in FIG. 2. The same members as those in FIG. 11 are denoted by the same reference numerals, and description thereof will be omitted.

Description of portions different from FIG. 11 is a detection signal processing unit 50 corresponding to the amplification unit 4 shown in FIG. 11 and showing a specific configuration. That is, the infrared amplifier circuit 5 amplifies the infrared voltage Vs output from the infrared sensor 3a.
1. a temperature-sensitive amplifier 52 for amplifying the temperature-sensitive voltage Vt output from the temperature-sensitive sensor 3b; and a peak hold circuit 5 for holding the peak value of the output voltage Vs of the infrared amplifier 51.
3. The output voltage Vs of the infrared amplifier circuit 51 and the output voltage Vsp of the peak hold circuit 53 are input to input terminals I ₁ and I ₂ respectively, and the output terminal 0
, An A / D conversion circuit 55 for converting the infrared voltage Vs or Vsp output from the switching circuit 54 into digitized infrared data Vd, and an output of the temperature-sensitive amplifier 52. An A / D conversion circuit 55 for converting the voltage Vt into digitized temperature-sensitive data T ₀ , wherein the infrared voltage Vs and the temperature-sensitive voltage V input from the detection unit 3 are provided.
t is digitized infrared data Vd and temperature-sensitive data T ₀
And output.

The calculating section 60 corresponds to the calculating section 5 in FIG. 11, but includes a temperature calculating circuit 61 corresponding to the emissivity input means 5a, the filter correcting means 5b, and the calculating circuit 5c.
Temperature data Tb calculated by the temperature calculation circuit 61
₁ is input and the display drive circuit 62 for displaying the temperature on the temperature display section 6a of the display device 6 and the comparison infrared data Vd output from the detection signal processing section 50 at the time of temperature measurement processing such as function check are input; zero detecting circuit 63 for outputting a detection signal S ₀ to turn on the measurement permission mark 6b of the display device 6 when the comparison infrared data Vd is detected to be zero, the detection signal processing section 50 The sensitivity correction arithmetic circuit 6 for inputting the temperature-sensitive data T ₀ output from the CPU and calculating and outputting the sensitivity R according to the equation (8) shown in FIG.
4 and a sensitivity data input for outputting a value externally input as sensitivity data D based on the light receiving area S of the infrared sensor 3a and the amplification factor A of the infrared amplifier circuit 51 shown in the above equation (6). Means 65.

A switch circuit 90 is connected to the major switch SWm operated by the major buttons 14 and 15 and the check switch SWc operated by the check button 12 shown in FIG. When pressed, major switch SW
m is turned on, and a major signal Sm is output from the M terminal.

When the radiation thermometer 1 is set in the storage case 30 as shown in FIG. 6, the check button 12 is pressed, the check switch SWc is turned on, and the check signal Sc is output from the C terminal.

The major signal Sm output from the M terminal of the switch circuit 90 is supplied to the enable terminals E of the temperature calculation circuit 61 and the sensitivity correction calculation circuit 64, thereby setting both circuits to the calculation mode and at the same time. The zero detection circuit 63 is reset.

The check signal Sc output from the C terminal of the switch circuit 90 is supplied to the enable terminal E of the zero detection circuit 63, the control terminal C of the switching circuit 54, and the reset terminal R of the peak hold circuit 53.

Next, the operation of the radiation thermometer 1 having the above configuration will be described.

First, in the initial state where the power switch 13 of the radiation thermometer 1 shown in FIG. 2 is turned on, both the check switch SWc and the major switch SWm are turned off. Neither Sc nor the major signal Sm is output.

As a result, the operation section 60 is operated by the temperature operation circuit 6
1 and the sensitivity correction operation circuit 64 are set to the non-operation mode,
Zero detection circuit 63 is also set to the non-operation mode.

The switching circuit 54 of the detection signal processing unit 50
_The voltage Vsp input to the _two terminals is selectively output to the output terminal 0, and the reset of the peak hold circuit 53 is released, and the peak hold circuit 53 is in an operating state. The above is the initial state. Next, the function check mode will be described.

When the radiation thermometer 1 is mounted on the storage case 30 as shown in FIG. 6, the check button 12 is pressed against the button pressing portion 30d of the storage case 30 to turn on the check switch SWc of FIG. The tip of the probe 16 is set at the position of the reflection plate 31.

As a result, the switch circuit 90 of FIG. 1 outputs the check signal Sc from the terminal C when the check switch SWc is turned on, and the peak hold circuit 5
3, supply to the switching circuit 54 and the zero detection circuit 63. Detection signal processing section by the check signal Sc is supplied 50 the voltage Vs is the peak hold circuit 53 switching circuit 54 at the same time is reset to be supplied to the input terminal I ₁
Is switched to a state of selectively outputting to the output terminal 0, and the A /
The D conversion circuit 55 digitally converts the infrared voltage Vs and outputs infrared data Vd.

In the operation section 60, the temperature operation circuit 61 and the sensitivity correction operation circuit 64 are set to the non-operation mode, and only the zero detection circuit 63 is in operation. The above is the state of each part in the function check mode. In this function check mode, the operation of the radiation thermometer 1 is as follows: the infrared light reflected by the reflector 31 forming the reference comparison surface is reflected by the infrared sensor 3a and the infrared amplifier circuit. The comparison infrared data Vd converted by the switching circuit 54, the A / D conversion circuit 55 is determined by the zero detection circuit 63. If the comparison infrared data Vd is zero, the zero detection circuit 63 detects the output terminal 0. outputs a signal S _0, to turn on the measurement permission mark 6b of the display device 6.

Here, the contents of the function check mode will be described.

As described above, in FIG. 4, the infrared sensor 3a, the light guide tube 20, and the hard cap 21 are connected to each other by the metal housing 19 having good heat conductivity, thereby achieving a thermal balance. The function check is a mode for confirming that the heat balance is well maintained.

That is, the infrared radiation energy radiated from the light guide tube 20 and the hard cap 21 at the temperature T is reflected by the reflection plate 31 and enters the infrared sensor 3a. The infrared radiation energy is also radiated from the infrared sensor 3a at the temperature T ₀ , and the energy W obtained by subtracting the radiation from the incident light is W = εσ (T ⁴ −T ₀ ⁴ ), and if T = T ₀ , there is no energy W, and FIG.
Are zero, and the zero detection circuit 63 outputs a detection signal S ₀ .

That is, it is confirmed by the lighting of the measurement permission mark 6b that the heat source serving as noise does not exist in the portion of the optical system 2 and the heat balance is in an equilibrium state and accurate temperature measurement is possible. .

The zero detection circuit 63 determines the value of the comparison infrared data Vd as a digital value, and the determination value does not need to be strictly zero, and if it is smaller than a predetermined determination value, as negligible, and outputs a detection signal S _0.

However, if T ≠ T ₀ in the equation (5), that is, if there is a temperature difference between the infrared sensor 3a, the light guide tube 20 and the hard cap 21, the energy W of the difference exists. Therefore, the value of the comparison infrared data Vd becomes higher than the determination level of the zero detection circuit 63. As a result, the detection signal S
₀ is not output and the measurement permission mark 6b is not turned on.

When the radiation thermometer 1 is actually used, the state of T ≠ T ₀ occurs as described above in the following case. That is, when is suddenly changed radiation thermometer 1 of ambient temperature, the or thermal capacity between each element in this case, becomes T ≠ T ₀ by a difference in responsiveness, heat balance is an irregular, of the difference Since the measurement error occurs only in the value of the comparison infrared data Vd based on the energy W, the measurement is not possible.

In this state, if the metal housing 19 is left at a certain environmental temperature for a while,
, Heat stability is performed through this, and eventually the heat balance state is stabilized, and the measurement is permitted. However, this stabilization time may require tens of minutes.

As described above, according to the present invention, comparative infrared data obtained by measuring the temperature of the reference comparative surface is used for a function check, and the measurement is permitted in a state where the heat balance state is stable. However, in the present invention, this comparative infrared data can be used for any temperature measurement processing, for example, the infrared data itself even when the heat balance exceeds a predetermined value.

The above is the function check mode. Next, the temperature measurement mode will be described.

After confirming that the measurement permission mark 6b is lit in the function check mode, the radiation thermometer 1 is removed from the storage case 30.

When the radiation thermometer 1 is removed from the storage case 30, the check switch SWc is turned off by releasing the pressing of the check button 12, and the check signal Sc output from the C terminal of the switch circuit 90 is output.
Disappears.

[0144] As a result the peak hold circuit switching circuit 54 at the same time the reset is released 53 returns to the selection state of the input terminal I _2, also be zero detection circuit 63 returns to the non-operating state.

As a result, the detection signal processing unit 50 converts the peak voltage Vsp held by the peak hold circuit 53 from the infrared voltage Vs output from the infrared amplifier circuit 51 through the switching circuit 54 into an A / D converter. The peak voltage Vsp is supplied to a circuit 55 to output infrared data Vd obtained by digitizing the peak voltage Vsp.

The zero detection circuit 63 of the arithmetic unit 60 returns to the non-operating state, but the detection signal S ₀ is held by the storage circuit provided in the zero detection circuit 63, so that the measurement of the display device 6 is permitted. The mark 6b keeps the lighting state.

The detection signal S ₀ of the zero detection circuit 63
Remains until the storage circuit is reset by the supply of the major signal to the reset terminal R.

The measurement standby state has been described above. In this state, the probe 16 of the radiation thermometer 1 is inserted into the outer ear hole 41 as shown in FIG.

That is, when the major buttons 14 and 15 are pressed, the major switch SWm in FIG.
The signal becomes N, and the major signal Sm is output from the M terminal of the switch circuit 90.

As a result, at the same time as the temperature calculating circuit 61 and the sensitivity correction calculating circuit 64 are set to the calculating mode, the zero detecting circuit 63 is reset and the measurement permission mark 6b of the display device 6 is turned off.

The probe 1 inserted into the outer ear hole 41
6 (the optical system 2 and the detection unit 3 in FIG. 1)
Is converted into an infrared voltage Vs by the infrared sensor 3a of the detection unit 3,
After being amplified to the voltage Vs at 1, the peak hold circuit 53
Holds the peak voltage Vsp.

Further, the peak voltage Vsp is converted into infrared data Vd by the A / D conversion circuit 55 and supplied to the arithmetic unit 60.

The temperature sensor 3b buried in the metal housing 19 shown in FIG. 4 detects the temperature of the infrared sensor 3a, converts the temperature into a temperature-sensitive voltage Vt, and then outputs the temperature-sensitive data T ₀ by the A / D conversion circuit 56. And supplies it to the arithmetic unit 60.

[0154] The arithmetic unit 60 by the infrared data Vd and the temperature-sensitive data T ₀ is supplied, first sensitivity correction calculation circuit 64 is based on temperature-sensitive data T ₀ and 19 that is supplied (8) To calculate the value of the sensitivity R. Note that the fluctuation rate β is β = −0.003.

Next, the temperature calculation circuit 61 inputs the sensitivity R calculated by the sensitivity correction calculation circuit 64, the sensitivity data D from the sensitivity data input means 65, and the coefficient a of the fourth order from the filter correction means 5b. The sensitivity coefficient K ₃ of the lever system is calculated by K ₃ = aRD.

Next, the calculated sensitivity coefficient K ₃ , the emissivity ε from the emissivity input means 5a, and the symmetric axis temperature b from the filter correction means 5b are input, and the calculation of the equation (17) is performed.

[0157] _{Vd = εK 3 {(Tb 1} -b) 4 - (T 0 -b) 4} ... (17) still (17) calculates the temperature data Tb ₁ shown in (18) by organizing formula I do. Note that the outer ear canal is surrounded at the same temperature, and the emissivity ε is set to ε = 1 since the cavity can be regarded as a black body.

[0158]

(Equation 10) Then, the temperature data Tb ₁ is displayed on the numeral display section 6a of the display device 6 via the display drive circuit 62.

The above is one temperature measurement operation. This series of operations will be described with reference to the flowchart of FIG.

First, when the probe 16 is inserted into the outer ear canal 41 (step 1), the radiated infrared energy from the eardrum 42 becomes the infrared voltage Vs, and the peak voltage Vsp is held by the peak hold circuit 53 (step 2). . Next, the presence or absence of the major signal Sm is determined (step 3).
If the measure buttons 14 and 15 are not pressed, the result is NO, and only the peak value hold operation of step 2 is performed.

When the measure buttons 14 and 15 are pressed, the result is YES, and the zero detection circuit 63 is activated by the measure signal Sm.
There is reset (Step 4) the sensitivity correction calculation circuit 64 together performs the calculation of the temperature-sensitive data T ₀ read in (step 5) sensitivity R (Step 6).

The temperature calculating circuit 61 reads the emissivity ε, the coefficient a, the sensitivity R, and the sensitivity data D (step 7),
a, R, and calculates the sensitivity coefficient K ₃ with D (Step 8).

Further, the temperature calculation circuit 61 calculates the symmetry axis temperature b
A peak-held read infrared data Vd (step 9) calculates the temperature data Tb ₁ (Step 1
0).

[0164] The display drive circuit 62 performs the temperature displayed on the display device 6 to input the temperature data Tb ₁ (step 11) that the temperature measurement operation is terminated by the.

Next, the role of the peak hold circuit 53 shown in FIG. 1 will be described with reference to FIG.

FIG. 9 shows a temperature measurement curve of the radiation thermometer 1 according to the present invention, which is compared with the temperature measurement curve of the conventional electronic thermometer shown in FIG.

The horizontal axis is the temperature measurement time, the vertical axis is the measured temperature, and the measurement site is the outer ear hole 41. The temperature curve Hs of the outer ear hole 41 and the measured temperature curve Ms of the radiation thermometer 1 coincide.

As described above, the hair growth 43 and earwax 44 are present in the outer ear hole 41 of the ear shown in FIG.
3 and the earwax 44 are heated to a temperature very close to that of the eardrum 42 in the same manner as the eardrum 42, and this state is shown in FIG.
At time t ₁ .

That is, the moment when the probe 16 is inserted into the outer ear hole 41 is the time point t _1. At this moment, the temperature inside the outer ear hole 41 is almost at the temperature Tb _1. The radiant energy enters and is stored in the peak hold circuit 53 of FIG. 1 as the peak voltage Vsp.

However, immediately after the probe 16 is inserted, the temperature in the outer ear hole 41 is rapidly cooled by the probe 16 as shown by a temperature curve Hs. With the decrease, the infrared voltage Vs detected by the infrared sensor 3a
Also falls to the level of the temperature measurement curve Ms, and cannot exceed the peak voltage Vsp. Therefore, the peak voltage Vsp at the time point t ₁ is stored in the peak hold circuit 53.

[0171] Then but the reduced temperature curve Hs is restored to the original temperature level Tb ₁ are those requiring approximately 10 minutes to the time, the reason will be explained by FIG.

That is, although the temperature of the eardrum 42, the hair growth 43, the earwax 44, etc. all decrease due to the insertion of the probe 16 into the outer ear hole 41, the eardrum 42 among the above-mentioned parts is relatively quickly owing to heat conduction from the body. it is possible to return to the level of temperature Tb _1.

[0173] However low downy 43 or earwax 44 having adhesiveness between the body results in requiring a time of about 10 minutes to return to the level of the temperature Tb ₁ for low thermal conductivity from the body.

Therefore, the internal temperature of the outer ear hole 41 becomes the temperature Tb ₁
At the moment when the probe 16 is inserted.
Only at _one point. Since a series of arithmetic processing of the radiation thermometer 1 cannot be performed with this short-time infrared radiation energy, the instantaneous peak voltage Vs as shown by a dotted line in FIG.
p is stored in the peak hold circuit 53 as analog data, and A / D is stored using the stored peak voltage Vsp.
The temperature can be measured by performing the conversion and a series of arithmetic processing.

That is, in a radiation thermometer having no preheating device as in the present invention, a peak hold circuit 53 is required. By using the peak hold circuit 53, the temperature Tb ₁ at the time point t ₁ can be extremely short. It becomes possible to measure.

FIG. 10 is a specific configuration diagram of the peak hold circuit 53. An input buffer 80, an output buffer 81, a diode 82 for preventing backflow, a capacitor 83 for charging a signal, and a voltage charged in the capacitor 83 are stored. A switch transistor 84 for discharging, receives an infrared voltage Vs, outputs a peak value as a peak voltage Vsp, and outputs a reset terminal R
When the switch transistor 84 is turned on by the check signal Sc supplied to the capacitor 83, the charged voltage of the capacitor 83 is discharged.

(Other Embodiments) FIG. 12 is a sectional view of a head section 110 according to another embodiment of the present invention. The same members as those in FIG.

12 differs from FIG. 4 in that the light guide tube 20 is exposed by providing a through hole 19f in the cylindrical portion 19a of the metal housing 19, and the temperature-sensitive sensor 3c is provided on the exposed portion of the light guide tube 20. Has been fixed.

The temperature sensor 3c is the same as the temperature sensor 3b.
The fixing method is the same as that of the first embodiment.

That is, the difference from the first embodiment is as follows.
This is a method for correcting the heat balance in the probe 16. While the first embodiment employs a method in which the heat balance is confirmed in the function check mode and measurement is permitted, the measurement is not permitted while the heat balance is not obtained, whereas this embodiment is different from the first embodiment. By providing two temperature-sensitive sensors 3b and 3c, the temperature difference between the infrared sensor 3a and the light guide tube 20 is detected. If the temperature difference is abnormally large, the measurement is not permitted. If the temperature difference is smaller than a predetermined set value, the temperature measurement is permitted even if the heat balance is not taken, and the temperature data is calculated by performing a calculation in which the temperature difference is corrected to the measured value. The measurement conditions of the radiation thermometer are widened.

Hereinafter, the circuit configuration and operation will be described with reference to FIG. 13. The same members as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

The detection section 3 is provided with a temperature sensor 3c for measuring the temperature Tp of the light guide tube 20, as shown in FIG. The detection signal processing unit 50 includes a switching circuit 5
4, the output voltage Vs of the peak hold circuit 53
p is directly supplied to the A / D conversion circuit 55, and a temperature-sensitive amplification circuit 57 and an A / D conversion circuit 58 are newly provided to output the temperature-sensitive data Tp.

In the operation section 60, the emissivity input means 5a shown in FIG. 1 has the emissivity .epsilon.p of the light guide tube 20 set therein, and a temperature difference detection circuit 67 is provided in place of the zero detection circuit 63. The temperature difference detection circuit 67 receives the temperature data T ₀ of the infrared sensor 3a detected by the two temperature sensors 3b and 3c shown in FIG. The temperature difference is determined for the obtained measurement limit temperature difference Td.

When | T ₀ −Tp | <Td, that is, when the temperature difference is smaller than the limit temperature difference, the detection signal S ₀ is output to turn on the measurement permission mark 6 b of the display device 6. This temperature difference determination operation is always performed while the power switch 13 shown in FIG. 3 is ON.
The operation of the check button 12 as in the first embodiment is not required.

When the measurement permission mark 6b is turned on, the operation enters the temperature measurement mode as in the first embodiment.
The difference is that the temperature calculation circuit 61 receives the temperature-sensitive data Tp of the light guide tube 20 in addition to the data described with reference to FIG. to calculate the temperature data Tb _2.

[0186]

[Equation 11] The temperature data Tb ₂ is obtained by correcting the temperature difference by calculation, and is displayed on the temperature display section 6a of the display device 6 via the display drive circuit 62.

Further, the check signal Sc output from the switch circuit 90 according to the present embodiment is
Reset only. Therefore, when re-measuring the temperature, it is necessary to reset the peak hold circuit 53 by operating the check button 12 after confirming the lighting of the measurement permission mark 6b.

As described above, according to the present embodiment, the temperature can be measured without waiting for each part of the probe 16 to be completely thermally balanced, so that the interval between repeated measurements can be shortened. Since a function check by infrared radiation is not required, a switching circuit and a storage case are not required, and the configuration can be simplified.

In the present embodiment, the configuration in which the second temperature-sensitive sensor 3c is brought into close contact with the light guide tube 20 has been described as an optimal embodiment, but the present invention is not limited to this. That is, the purpose of the second temperature sensor 3c is to make the light guide tube 2 more sensitive to the ambient temperature than the embedded portion of the temperature sensor 3b.
The temperature sensor 3c is mounted on a circuit board on which an IC chip for measurement is mounted, considering that the surface temperature of the light guide tube 20 is substantially equal to the surface temperature of the light guide tube 20. Then, the ambient temperature is measured, and this can be sufficiently used as the surface temperature of the light guide tube 20.

[0190]

As described above, according to the present invention, at the time of temperature measurement, comparative infrared data is detected with the infrared sensor of the radiation thermometer facing a predetermined reference comparison surface, and the light guide means and the red light are detected. The thermal balance of the outside sensor can be checked, and various temperature measurement processes, for example, disabling or obtaining a temperature measurement operation in a state where the heat balance is irregular, using the comparative infrared data obtained at the time of this function check. It is possible to easily perform temperature calculation correction and the like using the obtained infrared data. As a result, a small battery can be driven, and a small and inexpensive radiation thermometer with a short measurement time can be realized.

[Brief description of the drawings]

FIG. 1 is an overall block diagram of a radiation thermometer showing a first embodiment of the present invention.

FIG. 2 is a back view of the radiation thermometer according to the first embodiment.

FIG. 3 is a side view of the radiation thermometer shown in FIG.

FIG. 4 is a sectional view showing a main part of a head of the radiation thermometer shown in the first embodiment.

FIG. 5 is an enlarged sectional view of a distal end portion of the probe according to the first embodiment.

FIG. 6 is a side view showing a state where the radiation thermometer according to the first embodiment is mounted on a storage case.

FIG. 7 is a sectional view of an ear showing a measurement state.

8 is a flowchart showing the operation of the radiation thermometer shown in FIG.

FIG. 9 is a diagram showing a temperature measurement curve of the radiation thermometer of the present invention.

FIG. 10 is a configuration diagram of a peak hold circuit shown in FIG. 1;

FIG. 11 is an overall block diagram showing a basic example of a radiation thermometer according to the present invention.

FIG. 12 is a cross-sectional view of a head section showing another embodiment of the present invention.

FIG. 13 is an overall block diagram of a radiation thermometer according to another embodiment.

FIG. 14 is a temperature measurement curve diagram of a conventional contact-type electronic thermometer.

FIG. 15 is a wavelength spectrum characteristic diagram of infrared radiation energy of an object.

FIG. 16 is a transmission wavelength characteristic diagram of a silicon filter.

FIG. 17 is a characteristic diagram showing a relationship between absolute temperature and radiant energy.

FIG. 18 is a block diagram of a conventional radiation thermometer.

FIG. 19 is a temperature characteristic diagram of a conventional infrared sensor sensitivity.

[Explanation of symbols]

1, 70 radiation thermometer, 2 optical system, 3a infrared sensor, 3b, 3c temperature sensor, 5, 60 arithmetic unit, 5b
Filter correction means, 16 probes, 20 light guide tubes,
30 storage case, 31 reflector, 50 detection signal processing unit, 53 peak hold circuit, 61 temperature calculation circuit,
63 Zero detection circuit, 64 Sensitivity correction operation circuit.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01J 5/10

Claims (2)

(57) [Claims] A light guide for condensing heat radiation from an object to be measured; an infrared sensor for receiving the heat radiation condensed through the light guide and outputting an electric signal; A temperature sensor for measuring an absolute temperature and outputting an electric signal; a detection signal processing for outputting the infrared data and the temperature data which are digitized based on the electric signal from the infrared sensor and the temperature sensor; Means, temperature calculating means for calculating temperature data of the object to be measured based on the infrared data and temperature-sensitive data, and whether the infrared sensor is a reflector located on the tip side of the light guiding means.
The comparative infrared data is detected in a state facing the reference comparison surface composed of
Zero detection circuit that determines that there is and outputs a comparison detection signal
A comparison detection circuit having a function of displaying temperature according to the temperature data and detecting zero
The measurement is turned on by the comparison detection signal output from the circuit.
And a display device provided with a fixed permission mark, and the comparison infrared data obtained by measuring the temperature of the reference comparison surface .
Thermal balance between the light guiding means of a radiation thermometer and an infrared sensor
Heat balance reaches the desired equilibrium state.
A radiation thermometer that suspends temperature measurement until the temperature is measured . 2. The reflecting plate located on the tip side of the light guide means,
The radiation thermometer according to claim 1 , wherein the radiation thermometer is provided in a case that stores the radiation thermometer .