JPH0235322A - radiation thermometer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radiation thermometer, and particularly to a radiation thermometer system that does not use a heating device.

[Conventional technology]

In recent years, pen-shaped electronic thermometers have become popular as an alternative to glass thermometers.

The features of this electronic thermometer are that it is unbreakable and easy to read.
Although there is a buzzer to indicate the end of the temperature measurement, it takes about 5 to 10 minutes to measure the temperature, which is almost the same as a glass thermometer, which is why it is so troublesome to measure the temperature. This is because there are two reasons why the measurement time is long, and there is a problem with the method of inserting the sensor part into the armpit or mouth and bringing it into contact with the measurement area.

First, the skin temperature in the armpit and the mucous membrane temperature during the day do not reach body temperature before the temperature measurement starts, but by closing the armpit and mouth, the temperature gradually approaches body temperature.

Second, the thermometer sensor part is cooled to the surrounding density (・te,
This is because inserting the probe into the measurement site further lowers the temperature of the measurement site, which takes more time.

Considering the above reasons 1 and 2, consider the conditions for determining body temperature in a short period of time. Before starting temperature measurement, select an area that has a body temperature, and touch a cold sensor. If measurements can be made without shaking, short-time measurements will be possible.

Therefore, a radiation thermometer has been proposed that selects the eardrum as the part where body temperature is measured before the temperature measurement starts, and measures the temperature of that part without contact. (For example, JP-A-61-1174
Publication No. 22) Next, the principle of the radiation thermometer, which is the basis of the radiation thermometer described above, will be explained.

``All objects emit infrared radiation from their surfaces, and the amount of infrared radiation energy and spectral characteristics are determined by the object's absolute temperature, and also depend on the object's properties and finished surface condition.'' This physics It is based on the law of The law that shows this will be explained.

First, Blank's (Pβanck) law expresses the relationship between the radiation intensity, spectral distribution, and temperature of a black body.

W(λ, T): Monochromatic radiant emittance (3pectralra
diant emittance) CW/c cancellation/
[μm] T: Absolute temperature of black body [K] N: Wavelength of emitted radiation [μm] C: Speed of light 2998×10I0 [1cc] h Blank constant 6.625X10'-” CW-3e♂]k: Boltzmann constant 1..380X10-”” [W-seC
/40 FIG. 8 illustrates this Blank's law. It can be seen that the radiant energy increases as the temperature of the black body increases. Furthermore, the radiation energy changes depending on the wavelength, and the peak value of the distribution shifts toward shorter wavelengths as the temperature increases, but it can also be seen that the radiation is radiated over a wide wavelength band.

The total energy emitted from the black body is obtained by integrating W(λ, T) given by equation (1) with respect to λ from λ=0 to λ2 (9). This is Stefan Boltzmann (5t
efan-Bolzmann) law.

W, -fTW(λ+'r) dλ-σT4
...(2) W, = total radiant energy of blackbody C
W/cm] σ: Stefan-Boltzmann constant 5.673X10-12 [W/cm-deg'] (
2) As is clear from the equation, the total radiant energy W.

is proportional to the fourth power of the absolute temperature T of the blackbody light source.

It should also be noted that equation (2) is an equation obtained by integrating infrared radiation emitted from a black body over all wavelengths.

All of the above laws were derived for a blackbody with an emissivity of 1.00. However, in reality, most objects are not perfect radiators, and their emissivity is less than ]900. Therefore, it is necessary to correct it by multiplying it by the emissivity. Therefore, the radiant energy W2 of an object that is not a blackbody can be expressed as shown in equation (3).

Bijiεf”: W(;', T) dλ=εσT4
...(3) ε: Emissivity of the object Equation (3) expresses the infrared radiation energy emitted from the object and incident on the infrared sensor, but the same law applies to the infrared radiation from the infrared sensor itself. It's radiating. Therefore, the temperature of the infrared sensor itself is T. If it deviates from this, it means that an energy of σT is emitted in the infrared rays, and the energy W obtained by subtracting the radiation from the incident becomes Equation (4).

W=a (εT4+r T'a4-T,")
-(4) Ta: Ambient temperature of object γ: Measurement of reflectance of object Since the transmittance of the object can be regarded as zero, γ=1−ε holds true.

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

Furthermore, the infrared sensor has been installed in an environment with an ambient temperature Ta for a long time, and the infrared sensor temperature T. Assuming that is equal to the ambient temperature Ta, equation (4) becomes equation (5).

W2σ(εT4+γT o4 T [14)εσ(T
'-TO') ・
(5) FIG. 7 is a basic configuration diagram of a conventional radiation thermometer, and the configuration will be explained below based on the drawing.

The radiation thermometer 7 includes an optical system 2, a detection section 6, a detection signal processing section 4, a calculation section 5, and a display device 6.

The optical system 2 includes a condensing means 2a for efficiently condensing infrared radiation from a measurement object and a filter 2b having transmission wavelength characteristics. A cylindrical light guide tube whose inner surface is gold-plated is used as the light condensing means 2a. Also, filter 2
A silicon filter is used for b.

The detection section 6 includes an infrared sensor 6a and a temperature sensor 3b. The infrared sensor 6a detects the infrared sensor 6a from the incidence of infrared radiant energy collected by the optical distribution system 2.
The infrared radiation energy after subtracting the radiation from itself is converted into an electrical signal, that is, an infrared voltage VS. In addition, the temperature sensor 6
b is the temperature T of the infrared sensor 6a and its vicinity. It is placed near the infrared sensor 6a to measure the temperature, and outputs a temperature-sensitive voltage Vt. A thermopile is used for the infrared sensor filter a, and a diode is used for the temperature sensor 6b.

The detection signal processing unit 4 includes an amplification circuit that amplifies the infrared voltage ■s that is the output of the infrared sensor 6a, that is, the thermopile;
An infrared signal processing section 4a constituted by an A/D conversion circuit that converts the output voltage of the amplification circuit into digitized infrared data (d), and a temperature sensor 6b-'') f, s, diode. An increase d that amplifies the temperature-sensitive voltage Vt, which is the forward voltage of
] Temperature sensing data T that digitizes the output voltage of the circuit and its amplification circuit. It consists of a temperature-sensitive signal processing section 4b constituted by an A/D conversion circuit that converts the temperature into a temperature-sensitive signal.

The two signals d from the detection signal processing section 4,
To is converted into temperature data T by the calculation unit 5 and displayed on the display device B. Here, the calculation unit 5 includes an emissivity input means 5a for setting the emissivity ε of the measuring object, and (5)
It is composed of an arithmetic circuit 5C that performs arithmetic operations based on formulas.

With the above configuration, the temperature of the object to be measured can be measured in a non-contact manner, but how it works will be explained below.

First, the measurement object emits infrared radiation, and its wavelength spectrum distribution covers a wide wavelength range as shown in FIG. The infrared radiation is collected by the focusing means 2a, passes through the filter 2b having transmission wavelength characteristics, and reaches the infrared sensor 6a.

There is also other infrared radiation energy that reaches the infrared sensor 6a. One is the infrared radiation energy that is emitted from objects around the measurement object, and is reflected by the measurement object and then transmitted through the filter 2b. In addition, infrared radiation is emitted from the infrared sensor 6a or objects around it, and is reflected by the filter 21], and infrared radiation is emitted from the filter 21] and reaches the infrared radiation. There is energy.

The infrared radiation energy from the infrared sensor 6a can be expressed as equation (3). However, ε=1. ．． Let it be OO. That is, measuring the temperature of the infrared sensor 6a itself indirectly measures the infrared radiation energy from the infrared sensor 6a. For this purpose, the temperature sensor 6b is placed near the infrared sensor 6a, and the temperature T of the infrared sensor 6a and its surroundings is the same. is being measured.

The infrared sensor 6a then converts the infrared radiant energy W obtained by subtracting the emitted infrared radiant energy from the incident infrared radiant energy into an electrical signal. Since the infrared sensor 6a uses a thermopile, an infrared voltage VS proportional to this infrared radiant energy W is output.

Here, the infrared voltage ■s which is the output voltage of the infrared sensor 6a
is the product of the infrared radiation energy W per unit area and the light receiving area S of the infrared sensor 6a multiplied by the sensitivity R. In addition, infrared data V which is the output voltage of the infrared signal processing section 4a
d is the infrared voltage VS of the infrared sensor 6a multiplied by the amplification factor A of the infrared signal processing section 4a.

V8=R-W-8 Vd=A・■s Since the above relationship holds, equation (5) can be expressed as equation (6).

Vd-ε・σSR, A(T'-T”)
...(6)■d: Output voltage S of the infrared signal processing section 4a: Light receiving area R of the infrared sensor 3a: Sensitivity A of the infrared sensor: Amplification factor of the infrared signal processing section 4a Generally, K, = Assuming σSRA, the temperature T of the measuring object is calculated based on formula (6) and formula (7).

Vd-ε, (T'-T') However, the thermal infrared sensor temperature used in conventional radiation thermometers has no wavelength dependence, but the can package in which the infrared sensor is mounted A transparent filter made of silicon filter or quartz filter is placed in front of the window as a window material. This is because infrared radiation from an object has a wavelength spectral distribution as shown in Figure 8, so in order to reduce the influence of external light by transmitting only the wavelength band that is mainly emitted. Each of the above-mentioned transmission materials has unique transmission wavelength characteristics, and an appropriate transmission material is selected depending on the temperature of the object to be measured, the workability of the transmission material, the price of the material, etc.

FIG. 9 shows the transmittance of a silicon filter, which is one of the transmitting materials. It can be seen that the silicon filter shown in FIG. 9 transmits only a wavelength band of about 1 to 18 [μm]. And its transmittance is about 54%.

As mentioned above, an infrared sensor with a filter is a thermal type sensor and has no wavelength dependence, but it has a wavelength dependence that allows only a specific wavelength band to pass through the filter.

Therefore, equation (5) obtained by integrating the infrared radiant energy input to the infrared sensor with a filter over all wavelengths does not hold true for an infrared sensor with a filter that transmits only a specific wavelength band. Therefore, the result includes an error corresponding to this amount.

Furthermore, in the conventional configuration, the sensitivity R of the infrared sensor was treated as a constant, but the actual sensitivity R of the infrared sensor is the infrared sensor temperature T. According to the inventor's experiments, the output voltage (8) of the thermopile used as the infrared sensor 6a is actually measured using a blackbody to determine the sensitivity R, and the infrared sensor temperature T0 is As a result of plotting the change in sensitivity R at each temperature, the sensitivity R
The temperature dependence of is expressed by equation (8) (it was found that it can be approximated on a straight line).

R-α(1+β(To-T, n)) =-
(8) Here, α is T. This is the reference sensitivity R at 2 Tm. Tm is a representative temperature of the infrared sensor temperature, and is, for example, the infrared sensor temperature when the infrared sensor sensitivity is measured at a factory. β represents the degree of variation, 1 (
The fluctuation rate per deg) was -03 [%/deg].

It is half-heated that the above-mentioned fluctuation in sensitivity R results in an error.

Furthermore, the energy W shown in equation (5) is a value based on the assumption that the infrared sensor 3a and the condensing means 2a are in thermal balance, but in reality, the infrared sensor 6a and condensing means 2a are The temperature may be different from that of the optical means 2a, and in this case, infrared radiation from the condensing means 2a results in measurement errors.

As mentioned above, radiation thermometers have various error factors, but
However, ordinary radiation thermometers are intended to measure high temperatures, and their measurement range is about 0 to 300'C, and the measurement accuracy is about ±(2 to 3)0C. Errors due to sensitivity fluctuations of the infrared sensor, heat balance, etc. were considered negligible and no countermeasures were taken.

However, considering the measurement conditions as a thermometer, the temperature measurement range may be as narrow as about 33°C to 43°C, but the temperature measurement accuracy is required to be ±01°C.

Therefore, when the radiation thermometer is used as a thermometer, it is necessary to improve the accuracy of temperature measurement by taking some measures against errors caused by the filter characteristics, sensitivity fluctuations of the infrared sensor, heat balance, etc.

As a countermeasure against this problem, the radiation thermometer disclosed in Japanese Unexamined Patent Publication No. 61-11.7422 employs the following method.

That is, it has a three-unit configuration: a probe unit equipped with an infrared sensor, a chopper unit equipped with a target, and a charging unit.

A heating control means is provided for preheating the infrared sensor and the target to a reference temperature of the external ear canal (365° C.), and this heating control means is driven by charging energy from the charging unit.

When measuring body temperature, the probe unit is set in the chopper unit and the calibration plate is performed with the probe and target having an infrared sensor preheated by the heating control means, and then the probe unit is removed and inserted into the external ear canal. Body temperature is measured by inserting the device and detecting the infrared radiation emitted from the eardrum and comparing it with the infrared radiation emitted from the target.

Next, the reason why temperature measurement accuracy is improved by the above method will be explained.

This method eliminates various error factors by preheating a probe having an infrared sensor and a target to a reference temperature (365° C.) close to normal body temperature using a heating control means.

That is, by heating the glove to a reference temperature higher than room temperature, the infrared sensor is kept at a constant temperature regardless of the ambient temperature, thereby eliminating fluctuations in the sensitivity of the infrared sensor and making the error negligible. Further, by performing a calibration with the body temperature to be measured and the reference temperature of the target as values close to each other, and then performing a comparative measurement, the error due to the heat balance and the error due to the filter characteristics can be ignored.

Furthermore, since the glove is preheated to a temperature close to body temperature, if a conventional cold probe is inserted into the external ear canal, the temperature of the external ear canal and eardrum will drop due to the glove, and accurate body temperature measurement may not be possible. The problem is also resolved.

[Problem to be solved by the invention]

However, although the radiation thermometer disclosed in JP-A-61-3.174.22 is extremely superior in terms of temperature measurement accuracy,
On the other hand, since a heating control device with high control accuracy is required, there is a problem that the structure and circuit configuration thereof become complicated, resulting in an increase in cost. In addition, a long stabilization time was required to preheat the glove and target and control them to a constant temperature. Furthermore, since the energy used to drive the heating control device is relatively large, it is large in size and requires a charging unit with a power supply cord. It can be said that it is impossible to adopt this method.

The purpose of the present invention is to solve the above problems, thereby maintaining temperature measurement accuracy as a thermometer, making it portable and compact, and providing a radiation thermometer that eliminates the waiting time for measurements based on heat balance at a low cost. It is about providing.

[Failure to solve the problem]

The gist of the present invention for achieving the above object is as follows.

First, a light guide tube for collecting infrared radiation from a measurement object, an infrared sensor for converting the infrared radiation energy into an electrical signal, and a first temperature sensor for detecting the temperature of the infrared sensor and its surroundings. a sensor, a detection signal processing means that inputs the electric signal of the infrared sensor and the electric signal of the first temperature sensor and outputs digitized infrared data and temperature sensing data, respectively, and a body temperature that calculates body temperature data. In the radiation thermometer equipped with a calculation means and a display device that displays body temperature according to the body temperature data, a second temperature sensor for detecting the surface temperature of the light guide tube is provided, and the body temperature calculation means is red. Calculating body temperature data by inputting infrared data from an external sensor, first temperature data and second temperature data from the first temperature sensor and the second temperature sensor, The second temperature sensing sensor is provided in close contact with the surface of the light guide tube, and thirdly, the first temperature sensing data and the second temperature sensing data are inputted and the temperature difference therebetween is determined. A temperature difference measuring circuit is provided for determining the temperature difference, and the temperature difference measuring circuit outputs a detection signal when determining that the temperature difference is smaller than a predetermined measurement limit temperature difference,
Fourthly, the display device is provided with a measurement permission mark that is lit by a detection signal output from the temperature difference measuring circuit, and fifthly, the body temperature calculating means is configured to detect a temperature difference from the temperature difference measuring circuit. It is characterized by allowing the display of body temperature data based on the detection signal of.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 6 is a block diagram showing the basic configuration of the radiation thermometer according to the present invention, and the same elements as in FIG. 7 are given the same numbers.
The explanation will be omitted.

The measurement object in the radiation thermometer 1 is the eardrum of the ear, and the detection part B includes the surface of the light collecting means 2a in addition to the first temperature sensor 6b for detecting the ambient temperature of the infrared sensor 6a. A second temperature sensor 6c is provided for detecting temperature. The detection signal processing section 50 also includes a second temperature sensor 6c.
A temperature-sensitive signal processing section for processing the detection signal t is provided, and converts the detection signal Vt into temperature-sensing data Tp and outputs the same.

Furthermore, the calculation unit 60 uses the infrared data Vd, the temperature sensing data T
. In addition, temperature sensing data Tp based on the surface temperature of the condensing means 2a is input, body temperature data Tb corrected for the thermal balance of the optical system 2 is calculated from these data, and the body temperature is displayed on the display device B. Reference numeral 66 denotes a temperature difference measuring circuit, which measures the two temperature sensing data T. , Tp and determine the temperature difference. and the temperature difference T. -Tp is the measurement limit temperature difference T
d (.), a detection signal S is output to light up the measurement permission mark 6b provided on the display device 6 and permit the calculation operation of the calculation unit 60.

That is, the radiation thermometer 1 includes two temperature sensors 6b, 6.
The thermal balance of the optical system 2 is determined by C and the temperature difference measuring circuit 66, and if the temperature difference is too large to be measured, a detection signal S is sent. Prohibits output and prohibits body temperature measurement. However, if the temperature difference falls within a certain range, body temperature measurement is permitted without waiting until the heat balance is completely achieved, and the body temperature data is calculated by adding heat balance correction to the measured value. That's what I do.

Next, a specific configuration of the radiation thermometer 1 according to the present invention will be explained.

2 and 3 are a back view and a side view of the radiation thermometer 1. FIG. The radiation thermometer 1 is composed of a body temperature 1o and a head part 11. The display device 6 for displaying the body temperature is on the back side of the body temperature 1o, the check button 12 with a push button structure is on the front side, and there is a check button 12 on the side. A power switch 16 having a sliding structure and measure buttons 14 and 15 having a push button structure are provided.

Further, the head portion 11 is provided to protrude in a dogleg shape from the end of the body temperature 1o, and the tip of the head portion 11 is a probe 16, which is shown in FIG. It is composed of an optical system 2 and a detection section 6.

The radiation thermometer 1 is operated by turning the power switch 16 to
While inserting the probe 16 into the subject's external ear canal in the N position, simply turning on one or both of the measure buttons 14 and 15 instantly completes the temperature f411 determination, and the result is The body temperature is displayed on the display device 6.

FIG. 4 is a sectional view of the head portion 11, and the casing body 17
．． 18 is made of a clear resin molded body with extremely low thermal conductivity. The portion of the case body 17 that forms the globe 16 is a cylindrical tube portion 17a, and a metal housing 19 made of a lightweight metal with good heat conductivity, such as aluminum, is fitted into the tube portion 17a. There is. The metal housing 19 is provided with a cylindrical portion 19a having a through hole 19f for embedding a temperature sensing element, a hollow portion 19b communicating with the cylindrical portion 19a, and a base 19d having a recess 19C for embedding the temperature sensing element. Furthermore, a stepped portion 19e for attaching a filter is provided at the tip of the cylindrical portion 19a.And the cylindrical portion 19a is made of brass (Bu) and gold (A, U) on the inner periphery of the pipe.
A plated light guide tube 20 is fitted, and a hard cap 21 that allows selective passage of infrared rays and has a dustproof function is fixed to the stepped portion 19e at the tip. Furthermore, the base 1
A thermopile serving as the infrared sensor 6a is embedded in the hollow portion 19b of 9d, and the temperature sensor 6b is embedded in the recessed portion 19C with a sealing resin 22, 26, respectively.

Further, the temperature sensor 6C is fixed to the exposed portion of the light guide tube 20 exposed through the through hole 19f provided in the cylindrical portion 192 using molding resin.

The infrared sensor 6a and the temperature sensors 6b and 6C are connected to the wiring pattern of the circuit board 26 by lead wires 24, 25, and 27, respectively, and guided to an amplification circuit to be described later.

According to the above configuration, the infrared sensor 6a, the light guide tube 20, and the hard camp 21 are connected by the metal housing 19 with good thermal conductivity, so that a thermal balance can always be obtained. Even if the thermal balance is disrupted for some reason, the temperature of each part can be detected by the temperature sensors 6b and 3CK.

Further, 28 is a temperature measuring cover detachably attached to the probe 16, and is made of resin with poor thermal conductivity.
The tip portion 28a is made of a material that transmits infrared rays.

FIG. 5 is an enlarged sectional view of the tip of the probe 16, and the tip 28a of the temperature measuring cover 28 covers the tip of the probe 16 to prevent the probe 16 from coming into contact with the inner wall of the external ear canal. There is.

FIG. 1 is a block diagram of the radiation thermometer 1 shown in FIG. 2, which is a more specific version of the configuration shown in FIG. 6.

The detection signal processing unit 50 increases the infrared voltage Vt output from the infrared sensor 6a, the infrared amplifying circuit 51, the temperature sensor 61, and the temperature sensing voltage Vt output from the infrared sensor 6C. temperature-sensitive amplification circuits 52 and 57, a peak hold circuit 56 for holding the peak value of the output voltage Vs of the infrared multiplication circuit 51, and an output voltage ■s of the peak hold circuit 56.
A/D converting p into digitized infrared data vd
Temperature sensing data T obtained by digitizing the output voltage Vt of the conversion circuit 55 and the temperature sensing amplification circuit 52.57. and A/D conversion circuits 56 and 58 for converting the infrared voltage (3) and temperature-sensitive voltage (Vt) inputted from the detection unit 6 into digitized infrared data (d) and temperature-sensing data. T. and Tp
Convert and output.

The calculation section 60 includes an emissivity input means 5a, a filter correction means 5b, a body temperature calculation circuit 61, and the detection signal processing section 50.
Temperature sensing data T output from. a sensitivity correction calculation circuit 64 for calculating and outputting the sensitivity R according to the above equation (8), and a circuit for determining the light receiving area S of the infrared sensor 6a and the infrared increase 1] shown in the above equation (6). and a sensitivity data input means 65 for outputting a value input and set from the outside as sensitivity data D based on the amplification factor A of 51, and the emissivity input means 5a has an emissivity εp of the light guide tube 20. is set.

Note that since the external auditory foramen is surrounded by the same temperature and its cavity can be regarded as a black body, the emissivity ε can be treated as ε=1. is set.

Reference numeral 62 denotes a display/drive circuit that inputs the body temperature data Tb calculated by the body temperature calculation circuit 61 and displays the body temperature on the body temperature display section 6a of the display device 6.

90 is a switch circuit, which is a major switch SW operated by major buttons 14 and 15 shown in FIG.
m is connected to a check switch SWc operated by the check button 12, and when the measure button 14 or 15 is pressed, the measure switch SWm is turned OFF.
N, and the major signal Sm is output from the M terminal. Also, when the check button 12 is pressed, the check switch S
Wc is turned ON and a check signal Sc is output from the C terminal.

The measure signal Sm output from the switch circuit 900M terminal is supplied to each enable terminal E of the body temperature calculation circuit 61 and the sensitivity correction calculation circuit 64, thereby setting both circuits to calculation mode.

Also, the check signal Sc output from the C terminal of the switch circuit 90 is supplied to the reset terminal R of the peak hold circuit 56.

The temperature difference measuring circuit 66 includes two temperature sensors 3b and 3c.
Temperature data T detected by the infrared sensor 6a. Then, the temperature sensing data Tp of the light guide tube 20 is input, and a temperature difference judgment is performed for a predetermined measurement limit temperature difference Td. , that is, the temperature difference is smaller than the limit temperature difference (-), the detection signal So is output to light up the measurement permission mark 6b of the display device B, and the display permission terminal ED of the body temperature calculation circuit 61 is output.
By supplying the data to Tb, the calculation operation is permitted or the calculated body temperature data Tb is permitted to be displayed. Furthermore, this detection signal S
o as indicated by the dotted line (it can also be supplied to the display drive circuit 62 to permit display.

Next, the operation of the radiation thermometer 1 will be explained.

First, in the initial state when the power switch 16 shown in FIG. Both Sm are output (・な（・.

As a result, in the calculation section 60, the body temperature calculation circuit 61 and the sensitivity correction calculation circuit 64 are set to the non-calculation mode.

Further, the detection signal processing section 50 is in an operating state by canceling the reset of the peak hold circuit 56, and as a result, the detection signal processing section 50 performs a peak hold operation from the infrared voltage VSO outputted from the infrared amplification circuit 51. The peak voltage Sp held in the circuit 56 is supplied to the A/D conversion circuit 55, which outputs infrared data Vd obtained by digitizing this peak voltage Vsp, and also outputs two temperature sensing data To.
and Tp are output. As a result, the temperature difference measurement circuit 66 immediately starts temperature difference determination by inputting the temperature sensing data To and Tp, and this temperature difference determination operation continues while the power switch 16 is turned on.

However, as explained in FIG. 4, the infrared sensor 6a and the light guide tube 20 are thermally integrated by the metal housing 19, so in the normal state, the two temperature sensing data ToS
Tp is Toyuki Tp, and the temperature difference i+111
A detection signal So is output from the 1 constant circuit 66. As a result, the measurement permission mark 6b of the result display device 6 lights up to indicate that measurement is possible, and at the same time, the ED of the body temperature calculation circuit 61
The terminal becomes enabled.

The above is the measurement standby state, and from this state the radiation thermometer 1
After inserting the glove 16 into the external ear canal of the person to be measured, the body temperature is measured by pressing the measure button 14 or 15.

That is, when the measure buttons 14 and 15 are pressed, the measure switch S W m shown in FIG. 1 is turned on, and the measure signal Sm is output from the switch circuit 900M terminal.

As a result, in the calculation section 60, the body temperature calculation circuit 61 and the sensitivity correction calculation circuit 64 are set to the calculation mode.

The infrared radiation energy from the eardrum that enters the probe 16 (optical system 2 and detection unit 3 in FIG. 1) inserted into the external ear canal is detected by the infrared sensor 6a of the detection unit 6 to an infrared voltage Vs.
After being amplified to the voltage VS by the infrared amplification circuit 51, the peak voltage VS is converted to the peak voltage by the peak hold circuit 56.
p is held.

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

Furthermore, the temperature sensing sensors 61] and 6C embedded in the metal housing 19 in FIG. At 56 and 58, the temperature sensing data TO and Tp are converted and supplied to the calculation section 60.

By being supplied with the infrared data (d) and the temperature sensing data To and Tp, the calculation section 60 first calculates the value of the sensitivity R5 by the sensitivity correction calculation circuit 64 using the supplied temperature sensing data To and equation (8). calculate.

In addition, when a filter with transmission wavelength characteristics is used as an optical system member, it is necessary to
It is proportional to the fourth power of ” and (・Rather than calculating using the 5 law, the 4 of Stefan Boltzmann's characteristic curve
Calculation is performed using an approximation formula for radiant energy obtained by selecting the coefficient a in the next term, the amount of movement in the horizontal axis direction, and the amount of movement C in the vertical axis direction.

In other words, the coefficient a of the fourth-order term and the symmetry axis temperature S obtained here are values indicating the transmission wavelength characteristics of the filter 2b, and these four
The values of the coefficient a and the symmetry axis temperature 1 in the next terms are output from the filter correction means 5b.

The filter correction means 5b is a part of the calculation program memory of the calculation section 60, and the coefficient a of the fourth order term and the symmetry axis temperature are written therein.

Next, the body 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 term of the filter correction means 5b, and the system 4 to the sensitivity coefficient of 4 = aRD
Calculate by

Next, 4 is input into the calculated sensitivity coefficient, the emissivity εp from the emissivity input means 5a, and the symmetry axis temperature 1] from the filter correction means 5b are input, and body temperature data Tb is calculated by equation (8).

...(8) Also, a silicon filter is used as the filter 2b,
The axis of symmetry is set as l) = 45.95 CKj, and the emissivity of the light guide tube 20 is set as εp = 0.05.

This body temperature data Tb is obtained by correcting the temperature difference by calculation, and is displayed on the body temperature display section 6a of the display device 6 via the display drive circuit 62.

This completes one body temperature measurement, but the time required for this second measurement is about 2 seconds, and the body temperature measurement is instantaneous. If the body temperature is to be measured again (5), it is necessary to confirm that the measurement permission mark 6b is lit and then operate the check button 12 to reset the peak halt circuit 56.

τ2 Next, in the radiation thermometer 1, infrared sensor 6a and light guide tube 20
We will examine the conditions under which the heat balance is disrupted and To+Tp. When the radiation thermometer 1 is actually used, the conditions TO to Tp as described above occur in the following cases. In other words, this is a case where the usage environment range of the radiation thermometer 1 suddenly changes. In this case, the difference in heat capacity and response between each element causes To to Tp, and the infrared data ■d based on the energy W of the difference. Measurement may become impossible because a measurement error occurs in the value.

In other words, when the temperature suddenly changes, the exposed light guide tube 20
0 surface immediately follows the outside air flow, but the temperature sensing sensor 6b embedded in the metal housing 19 has a large sudden change in density because the tracking is delayed due to the heat capacity and thermal conductivity of the metal housing 19 and the infrared sensor 6a. Immediately after, 1To
-Tpl>Td, and measurement may become impossible.

If this state occurs, if you leave it for a while at a certain environmental temperature, heat conduction will occur through the metal housing 19, and the state will eventually stabilize to a thermal balance state, allowing measurement. , this stabilization time may require several tens of minutes.

However, as is well known, the temperature curve from when the thermal balance is disrupted to when it returns to the thermal balance state changes exponentially, so the time required for stabilization is 5/10, which is impossible to measure. The time for l > T d is about 1 to 2 minutes at most, and the remaining time is for measurable I.
It can be seen that the state is To-Tpl (Td).

Furthermore, considering that when the temperature change is small or gradual, measurement is almost always possible, the radiation thermometer 1 of the present invention can perform measurement almost all the time, except in very special cases. Moreover, it does not require troublesome calibration.

In this embodiment, a configuration in which the second temperature sensor 6C is brought into close contact with the light guide tube 20 is shown as an optimal embodiment, but the configuration is not limited to this. The purpose of the temperature sensor 6C is to detect the surface temperature of the light guide tube 200, which responds more sensitively to the ambient temperature than the buried portion of the temperature sensor 6b, and the surface temperature of the light guide tube 200 and the ambient temperature are approximately the same. Considering that the temperature sensor 6C is
It is possible to measure the ambient temperature by mounting a measurement IC chip on a circuit board, and to use this as the surface temperature of the light guide tube 200.

〔Effect of the invention〕

As described above, according to the present invention, two temperature sensors are provided in the probe, and body temperature data is calculated by correcting the temperature difference, and when the temperature difference measuring circuit determines the limit temperature difference of moromi, By prohibiting body temperature display, body temperature can be measured without waiting until each part of the probe is completely thermally balanced, which shortens the interval between repeated measurements and eliminates the need for troublesome calibration. We were able to obtain temperature measurement accuracy as a thermometer.

Also, 1lJt without using a conventional heating device.
Since it is possible to satisfy the one-constant accuracy, it is possible to drive it with a small battery, and it is possible to realize a radiation thermometer that takes a short measurement time and is small and inexpensive.

As a result, the present invention has a great effect in popularizing radiation thermometers, which were conventionally used only for medical purposes, for general household use.

[Brief explanation of the drawing]

1 and 6 are block diagrams of the radiation thermometer of the present invention, and FIGS. 2 to 5 show the structure of the radiation thermometer of the present invention. FIG. 2 is a back view, and FIG. (・Side view,
Figure 4 is a sectional view of the head, Figure 5 is an enlarged sectional view of the tip of the globe, Figure 7 is a block diagram of a conventional radiation thermometer, and Figure 8 is the wavelength spectrum characteristics of the infrared radiant energy of an object. FIG. 9 is a transmission wavelength characteristic diagram of a silicon filter. 1...Radiation thermometer, 6a...Infrared sensor, 3b, 3c...Temperature sensor, 5.60...Calculation unit, 16... ...Glove, 4.50...Detection signal processing section, 56...
・Peak hold circuit, 61...Body temperature calculation circuit, 66...Temperature difference measurement circuit.

Claims (5)

[Claims] (1) A light guide tube for concentrating infrared radiation from a measurement object, an infrared sensor for converting infrared radiation energy into an electrical signal, and a first temperature sensor for detecting the temperature of the infrared sensor and its surroundings. a sensor, a detection signal processing means that inputs the electric signal of the infrared sensor and the electric signal of the first temperature sensor and outputs digitized infrared data and temperature sensing data, respectively; and a body temperature that calculates body temperature data. In a radiation thermometer equipped with a calculation means and a display device that displays body temperature according to the body temperature data, a second temperature sensor for detecting the surface temperature of the light guide tube is provided, and the body temperature calculation means is configured to use infrared radiation. A radiation thermometer that calculates body temperature data by inputting infrared data from a sensor and first and second temperature data from the first and second temperature sensors. . (2) The radiation thermometer according to claim 1, wherein the second temperature sensor is provided in close contact with the surface of the light guide tube. (3) A temperature difference measuring circuit is provided which inputs the first temperature sensing data and the second temperature sensing data and determines the temperature difference therebetween, and the temperature difference measuring circuit is configured such that the temperature difference is a predetermined measurement limit temperature. The radiation thermometer according to claim 1, wherein the radiation thermometer outputs a detection signal when determining that the difference is smaller than the difference. (4) The radiation thermometer according to claim 3, wherein the display device is provided with a measurement permission mark that is lit by the detection signal output from the temperature difference measurement circuit. (5) The radiation thermometer according to claim 3, wherein the body temperature calculation means allows display of body temperature data based on a detection signal from the temperature difference measuring circuit.