JPH1151769A - Radiation thermometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a radiation thermometer where self-diagnostics can be made by applying light to an object to be measured from a light source via an optical system for indicating a measurement position, obtaining the radiation energy of the light source entering a sensing element, and performing self- diagnostics based on the change. SOLUTION: A driving means 14 is activated with a processing means 9 by an operation means 13, light for a spot marker is applied to an object 1 to be measured from a light source 15 through a beam splitter 4 and a lens 21 or the like, and a site to be measured can be visually verified. One part of the light of the light source 15 is applied to a sensitive element 7 via the beam splitter 4, a reflection mirror 5, and the beam splitter 4. The light source 15 is turned on and off before starting measurement, a radiation energy constituent L0 being reflected by the mirror 5 owing to/the difference of the detection output is obtained, a measurement value L2 is obtained in the same manner if required, the difference is compared with measurement accuracy by the processing means 9, and a self state is diagnosed based on the change state. Error information is indicated on a display means 11 and is informed to a host computer by a communication means 12, and self calibration is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation thermometer for measuring the temperature of an object using radiant energy.

[0002]

2. Description of the Related Art When a radiation thermometer is used for a long time, each part of the radiation thermometer, such as an optical system and a detecting element, is deteriorated, causing a measurement error. For this reason, it is desired to grasp this state of deterioration. Usually, the reference blackbody furnace is aimed at the radiation thermometer periodically or when necessary, and the radiation thermometer is calibrated.

[0003]

However, when calibrating the radiation thermometer using the reference black body furnace, the radiation thermometer should be removed from the installation location and brought into the place where the reference black body furnace was installed. Alternatively, the standard black body furnace must be brought into the place where the radiation thermometer is installed, and the radiation thermometer must be compared with the black body furnace each time, and the equipment becomes large-scale. It requires a lot of work and is complicated.

An object of the present invention is to provide a radiation thermometer capable of performing self-diagnosis with a simple configuration in view of the above points.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a radiation thermometer for measuring the temperature of an object to be measured, and a light source for projecting light to the object to be measured via an optical system to indicate a measurement position, and this light source. The radiation thermometer includes a detection element to which the light is incident, and a processing unit that obtains radiant energy of the light source incident on the detection element and performs self-diagnosis based on a change in the energy.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 (a) is a structural explanatory view showing an embodiment of a radiation thermometer according to the present invention. In the figure,
The radiant energy from the measurement target 1 is a lens 21, a slit 3, a beam splitter 4 such as a half mirror, and a lens 2.
2. The light enters the detection element 7 through an optical system such as a filter 6. The radiation energy is converted into an electric signal by the detection element 7, amplified by a predetermined factor by the amplifier A1, converted into a digital signal by the AD converter 8, and input to the processing means 9 such as a μCPU. The processing means 9 performs calculations such as conversion to temperature by referring to a table or the like in the memory 10, and can display the temperature on the display 11 or transmit a temperature signal to a personal computer or the like via the communication means 12.

When necessary, the processing means 9 operates the driving means 14 by operating the operating means 13 to emit light from a semiconductor element light source such as a light emitting diode LED or a laser diode LD or a light source 15 such as an incandescent lamp. Light for a spot marker is projected onto the measurement target 1 through an optical system such as the beam splitter 4 and the lens 21 to indicate a measurement position, and a measurement site can be visually recognized by a human.

Here, a part of the light L2 of the light from the light source 15 passes through the beam splitter 4, is reflected by the reflection mirror 5, is reflected by the beam splitter 4 again, and is incident on the detecting element 7. .

That is, the radiant energy component from the measurement target 1 is L1, and the radiant energy component from the light source 15 is L2.
The output of the detection element 7 when the light source 15 is turned on is V1, and the output of the detection element 7 when the light source 15 is off is V1.
Assuming that 2, the following equation holds.

V1 = L1 + L2 (1) V2 = L1 (2) That is, when the light source 15 is on, the radiant energy component L1 of the measurement target 1 of the detection element 7 and the radiant energy component L2 reflected by the reflection mirror 5 are detected. When the light source 15 is off, only the radiant energy component L1 of the measurement target 1 is included.

Thus, L2 is obtained by the following equation, and the component L1 from the object 1 is removed.

L2 = V1−V2 (3) That is, the light source 15 is turned on / off before the start of the measurement, the L2 is measured in the equation (3), and the initial reference value (L0) is stored in the memory. 10 is stored. And
When necessary or at predetermined time intervals, the light source 15 is turned on and off, and the measured value L2 at this time is obtained. The processing means 9 compares the difference between the two L0 and L2, and diagnoses its own state based on a change such as a case where the difference exceeds the measurement accuracy or a case where the difference is increasing, and displays it as error information. Means 1
1 or can be notified to a host computer such as a personal computer by the communication means 12 and can be self-calibrated.

In addition to turning on and off the light source 15 itself to interrupt the light, a shutter (not shown) is provided in the optical path to the measurement target 1 (for example, before and after the lens 21) to provide the shutter to the measurement target 1. If the light of the light source 15 is intermittently detected and the light incident only on the detection element 7 when the shutter is closed is detected, the light component L2 of the light source 15 can be directly obtained. It can be carried out. The same applies to a case where a region having sufficiently large radiant energy such as a light source is used.

That is, the light source 15, the beam splitter 4, the lens 22, the filter 6
Can detect abnormalities in the optical system, the detection element 7, etc., and can perform self-diagnosis of each part of the radiation thermometer. The output of the detecting element 7 may be converted to a temperature, and the apparent temperature at the initial stage may be compared with the apparent temperature at the time of the check to detect an abnormality.

By the way, particularly when the light source 15 is a semiconductor element light source such as an LED or an LD, the temperature dependency is large, and the radiated energy varies depending on the temperature. Therefore, FIG.
A light source 15 and a temperature sensor 16 are provided on a metal block 17 as shown in FIG. 2B, and the temperature near the light source 15 is detected by the temperature sensor 16, amplified by an amplifier A2, and converted into a digital signal by an AD converter 8. , To the processing means 9. Then, the light source 1 corresponding to the temperature previously obtained and stored in the memory 10 is obtained.
The radiant energy component L2 from the light source 15 is corrected by the correction value of the output of 5, and the temperature is compensated so as to be a correct component. When a temperature sensor is incorporated in the light source 15 of the semiconductor element, temperature compensation can be performed using the output of the temperature sensor.

For example, if the output of the light source 15 is high when the temperature is high, it is sufficient to multiply and divide the coefficient by a factor that reduces the output to a constant value. The output L2a before correction with respect to T is correct according to the following equation.

L2 = F (T) · L2a = F ′ (T, L2a) (4) The compensated output may be compared with an initial value L0.

Further, as shown in FIG.
By controlling the driving means 14, the driving current i to the light source 15 is changed to i1 and i2, and the change of the output L2 of the above equation (3) at this time is obtained, and the output L21 at each current value i1 and i2 is obtained. , L22, a coefficient ki is obtained by the following equation.

Ki = (L22−L21) / (i2-i1) (5) Then, as shown in FIG.
, T2, T3,..., Coefficients k1, k2,
.., and the correction function G is stored in the memory 10. At the time of self-diagnosis, the driving means 14 is controlled by the processing means 9 to change the driving current of the light source 15 to i1 and i2, and the coefficient ki is obtained from the change in the output L2 of the above equation (3). The temperature T is obtained by using the correction function G as shown in FIG. Based on the temperature T, compensation as shown in equation (4) is performed, and a correct self-diagnosis is performed.

When the light source 15 is a semiconductor device, the voltage-current characteristics of the driving voltage and the flowing current have temperature dependence. Therefore, the temperature is obtained by using the voltage-current characteristics with respect to this temperature, and the temperature is compensated. You may.

The type of the detecting element, the type of the light source, the configuration of the optical system, etc. may be any other than the above-described embodiment of the radiation thermometer, and the self-diagnosis can be performed easily and easily.

[0022]

As described above, the present invention relates to a radiation thermometer for measuring the temperature of a measurement object, a light source for projecting light to the measurement object via an optical system to indicate a measurement position, The radiation thermometer includes a detection element to which the light of the light source is incident, and processing means for obtaining radiant energy of the light source incident on the detection element and performing self-diagnosis based on a change in the energy. In other words, the light source for the spot marker is used to detect abnormalities in each part of the radiation thermometer, such as the optical system, based on changes in the output of the light source. , Can perform self-calibration. Further, by intermittently connecting the light source, the influence from the object to be measured can be easily removed, and only the radiant energy of the light source can be taken out, so that an accurate self-diagnosis can be performed. Normally, the fluctuation of the light source is small and the stability is good, but when the light source has a temperature coefficient of a semiconductor element light source or the like, the temperature of the light source provided on the metal block is detected by the temperature sensor to compensate, or the driving current to the light source is The self-diagnosis and abnormality diagnosis can be performed with higher accuracy by obtaining the temperature of the light source from the change in the output of the detection element and the voltage-current characteristics when the temperature is changed, and performing the diagnosis with higher accuracy. Or send it to a host computer to perform comprehensive diagnosis and abnormality detection, further improving the reliability of the system. In addition, it is possible to grasp in advance abnormality information such as that the self is becoming abnormal, and to predict and predict in advance.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing one embodiment of the present invention.

FIG. 2 is an operation explanatory diagram showing one embodiment of the present invention.

[Description of Signs] 1 Measurement target 21, 22 Lens 3 Slit 4 Beam splitter 5 Reflection mirror 6 Filter 7 Detection element 8 A / D converter 9 Processing means 10 Memory 11 Display means 12 Communication means 13 Operation means 14 Driving means 15 Light source 16 Temperature sensor 17 Metal block A1, A2 Amplifier

Claims (4)

[Claims] 1. A radiation thermometer for measuring a temperature of a measurement object, a light source for projecting light to the measurement object via an optical system to indicate a measurement position, and a detection element to which light from the light source is incident. And a processing means for obtaining radiant energy of the light source incident on the detection element and performing self-diagnosis based on the change. 2. The radiation thermometer according to claim 1, wherein the processing means obtains the radiation energy of the light source from the output of the detection element when the light of the light source is interrupted. 3. A semiconductor device as a light source, wherein the light source is provided on a metal block, and the temperature of the light source is detected by a temperature sensor provided on the metal block or a temperature sensor incorporated in the light source itself, and temperature compensation is performed by processing means. Claim 1.
Or the radiation thermometer according to claim 2. 4. The light source according to claim 1, wherein the processing means compensates for the light source based on a change in the output of the detection element when the drive current to the light source is changed or from a voltage-current characteristic. The radiation thermometer according to any one of the above.