JPS585621A - Optical temperature measuring method - Google Patents

Abstract

PURPOSE:To facilitate the separation of excited light and luminescence and to make it possible to measure the temperature at a high speed by irradiating a constant excited light pulses on a phosphorescent and fluorescent substance and measuring an attenuatin delay time. CONSTITUTION:A light emitting device 1 emits the excited light pulses based on an electric signal of a control circuit 2. The light is transmitted through a beam splitter 11 and irradiated on the phosphorescent and fluorescent substance 4 placed in an atmosphere 5. The light which is emitted from the phosphorescent and fluorescent substance 4 are inputted in a light receiving device 7 through an optical fiber 10 and the beam splitter 11. The delay time of the attenuation starting time of the afterglow with respect to the excited pluse stopping time is measured by a control circuit 2. Thus, the separation of the excited light and the afterglow are naturally performed. Since the delay time of the attenuation starting time of the agterglow depends on the temperature, the temperature measurement is performed at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical temperature measurement method for measuring IL changes in a body to be measured by utilizing the fact that photoluminescence of a phosphor caused by light stimulation depends on temperature.

As is well known, when optical stimulation is applied to a phosphor placed in the temperature atmosphere of a temperature-measuring object, phosphor photoluminescence is generated. Figure 1 shows the relationship between an excitation light pulse A as a light stimulus and photoluminescence B resulting from this. have.

A conventional optical temperature measurement method using a phosphor as a temperature sensor includes a method of measuring the emission intensity It of the phosphor during the duration of an excitation light pulse A.

In this case, the excitation light pulse must be *11. However, measurements need to be made in real time. Furthermore, if the excitation light and its photoluminescence have similar wavelengths, it is difficult to separate and detect them, which requires special filters and complicates the optics and system of the detector. There is a drawback.

Therefore, as a method to eliminate this drawback, the decay time Tdt-
A method for measuring this has been proposed. According to this method, the excitation light pulse A and the photoluminescence B can be easily detected separately. However, the decay time Td depends on the material of the phosphor (
Depending on the situation, the measurement time can be on the order of several tens of hours (some even extend), so the disadvantage is that the measurement time is long.

This invention was made in view of the drawbacks and traps of the conventional technology, and the attenuation delay time from when the phosphor is stopped once to when the afterglow intensity of photoluminescence starts to attenuate is also temperature dependent. To provide an optical temperature measurement method that facilitates separate detection of excitation light and photoluminescence and enables high-speed electro-electric measurement by measuring this decay delay time. The purpose is to

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

FIG. 1 and FIG. 2 are diagrams showing one embodiment of the present invention. In FIG. 1, a constant excitation light pulse A is generated based on an electric signal from a control circuit 2 of a light emitter, and the excitation light pulse A is irradiated onto a phosphor 4 via an optical system 3. (It has become.

Four phosphor phosphors are placed in an atmosphere 5 that is affected by the temperature of the object to be measured, and photoluminescence B generated by an excitation pulse AK is guided to a light receiver 7 via an optical system 6. At this time, the photoluminescence B has emission characteristics that depend on the temperature of the atmosphere 5, and the photoluminescence B has a luminescence characteristic that depends on the temperature of the atmosphere 5, and is
An electrical signal as shown in the figure (converted and input to the control circuit 2).

In the control circuit 2, the decay delay time Tddl and T4d exposure are determined by well-known sampling and hold technology.
This attenuation delay time Tdd1. Tddt
The corresponding temperatures [Tt and Tt] are respectively determined.

The decay delay times Tddt and Tddl are measured based on a fixed reference excitation stop, in this example, the falling edge of the excitation light pulse that excites the phosphorescent material, and the afterglow intensity of the photoluminescent filter B decays from a fixed level. is the time up to the point where . It is a well-known technology that this afterglow intensity begins to attenuate from a certain level.

For example, a sampling technique (therefore, it can be easily detected) may be used. Note that the falling edge of the electric signal pulse of the control circuit 2 that drives the excitation/stop light emitting device 1, which is a fixed reference, may also be used.

Since the attenuation delay time Tdd of the afterglow of photoluminescence B is generally 411 times longer than the attenuation time Td explained in FIG. Since the characteristics are utilized, excitation light and photoluminescence can be separated naturally.

Therefore, as shown in FIG. It is sufficient to separate it from photoluminescence B.

Next, FIG. 5 is a diagram showing another embodiment of the present invention.

In the first embodiment, the repetition period of the excitation light pulse A is longer than the afterglow time, but since the attenuation delay time of the afterglow is measured, the repetition period of the excitation light pulse A is
If the return cycle is made slightly longer than the attenuation delay time, the attenuation delay time Tddt −Tddn
can be measured repeatedly. Therefore, the decay delay time T'dd ti and the re-excited T(1
(It is obtained as the average value of 1t~'rcid=, Tdd-1Tddk i-1, and the accuracy of measurement can be improved.

As detailed above, according to the present invention, it is possible to measure the decay delay time of photoluminescence emitted by a phosphorescent material, which makes it possible to easily separate excitation light from the light emitted by it, and at a high speed. Therefore, it is possible to provide an optical temperature measurement method that can perform accurate temperature measurement.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is an explanatory diagram of the afterglow characteristics of photoluminescence of a phosphorescent material, Figs. 2 and 4 are schematic configuration diagrams showing the optical temperature measuring device according to the present invention, and Fig. 3 The figure is an explanatory diagram showing one embodiment of the optical temperature measuring method according to the present invention, and 5th vA is an explanatory diagram showing another embodiment of the present invention. 4-... Phosphorescent material A... Excitation light Hals B... Photoluminescence () (Lus emission) Tddl, Tdd@,...・-・Tddn””・・
・Attenuation delay time patent applicant Tateishi Electric Co., Ltd. Figure 1 d Figure 2 Figure 3 Procedural amendments dated 8A14, 1980 Director General of the Japan Patent Office Shima 1) Haruki Tonol Case Indication Patent Application No. 103745 No. 1988 2 , Name of the invention Optical temperature measurement method 3, Relationship to the case of the person making the amendment Patent applicant address 10 Hanazono Tsuchido-cho, Ukyo-ku, Kyoto City Name (2)
94) Tateishi Electric Co., Ltd. Representative: Takao Tateishi 4, Agent address: 1-15-16-6 Uchikanda, Chiyoda-ku, Tokyo.
In column 7 of the detailed description of the invention in the specification subject to amendment, in the third line of page 3 of the specification of contents of the amendment, [several tens of hours -1]
[Corrected to several tens of msJ.

Claims (1)

[Claims] U) In an optical temperature measurement method that utilizes the temperature dependence of the luminescence characteristics of a phosphorescent material due to optical stimulation. A phosphor is placed at a position that is affected by the temperature of the body to be measured, and a constant excitation light pulse is irradiated onto it to cause it to emit pulsed light.After the excitation of the phosphor is stopped, the pulsed light is emitted. An optical temperature measurement method characterized in that the attenuation delay time until the luminescence intensity starts to attenuate is measured. c) The above-mentioned phosphor is continuously irradiated with a constant excitation light pulse, and the decay delay time is repeatedly measured. optical temperature measurement method.