JP3149218B2 - Temperature measuring endoscope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature measuring endoscope capable of measuring a temperature distribution of a portion to be measured in a non-contact manner.

[0002]

2. Description of the Related Art In a conventional temperature measuring endoscope, an infrared fiber or an infrared image transmitting fiber bundle for transmitting infrared light radiated from a part to be measured (hereinafter referred to as an "infrared fiber") is used. , It is simply inserted through the endoscope insertion portion.

[0003]

The temperature distribution of the portion to be measured is finally detected by converting infrared energy into an electric signal by a thermography device or the like connected to a base end of an infrared fiber or the like. .

[0004] However, infrared fibers and the like have absorption, and infrared energy is also emitted from the infrared fibers and the like. Therefore, the infrared energy incident on the thermographic device or the like includes not only the energy radiated from the measured portion but also the energy radiated from the infrared fiber itself.

Therefore, when the temperature in the endoscope insertion portion in which the infrared fiber or the like is arranged changes, the temperature of the infrared fiber or the like changes, and the infrared energy incident on the thermographic device or the like changes, and the detected temperature decreases. Will change.

For this reason, when a temperature measuring endoscope is inserted into a device to be measured, such as the inside of a device or a human body, and the temperature distribution is measured, the measurement temperature is not changed even though the temperature of the measuring unit does not change. Changes, resulting in temperature measurement errors. In particular, a large error occurs in a low temperature range of 80 ° C. or lower.

Hereinafter, the degree of the error will be examined. The spectral radiance emitted from a black body without surface reflection is calculated by Planck's equation.

M (T _B , λ) = c ₁ [exp (c ₂ / λT _B ) −1] ⁻¹ λ ^-5 where M (T _B , λ): From unit surface area of black body to unit time Emitted energy per unit wavelength [W · cm
⁻² · μm ⁻¹ ] λ: wavelength [μm] T _B : black body temperature [K] c ₁ , c ₂ : first and second radiation constants An attenuation system between the light source and the infrared detector When the fiber enters, the transmittance, emissivity and reflectance of the fiber are τ,
Assuming that ε and ρ, the infrared energy U incident on the infrared detector is proportional to the sum of the energy transmitted through the fiber, the energy radiated from the fiber itself, and the energy reflected from the fiber end face.

[0009] _{U = K {τM (T B} , λ) + εM (T F, λ) + ρM (T RT, λ)} where, K: proportional constant T _F: Temperature Fiber T _RT: temperature of measurement environment thus When the temperature of the fiber changes, the measured temperature also changes.

FIG. 2 is a graph showing the result of measuring a change in measured temperature due to a change in fiber temperature. The measurement was performed by controlling the temperature of a black body furnace having an emissivity of 1 and having no influence of surface reflection by a controller, and measuring the temperature of the black body furnace with a temperature measuring endoscope.

The infrared image transmitting fiber bundle of the temperature measuring endoscope changes its surrounding temperature from 20.degree. C. to 50.degree. C., whereby the temperature of the black body furnace with respect to the temperature change of the infrared image transmitting fiber bundle is changed. Was measured.

As a result, for example, comparing the measured temperatures when the temperature of the infrared image transmitting fiber bundle is 20 ° C. and 50 ° C., about 3 ° C. at a black body temperature of 80 ° C. and about 6 ° C. at a black body temperature of 40 ° C. There is a difference. This is a very serious problem if precise temperature measurements are required.

In order to solve this problem, it has been studied to attach a temperature detector such as a thermocouple or a thermistor for measuring the temperature of the infrared fiber or the like itself and perform calibration. However, since such a temperature detector is a contact type, it may cause a breakage or breakage of flexibility, which is one of the advantages of an infrared fiber or the like. Further, when there is a temperature distribution along the longitudinal direction of an infrared fiber or the like, there is a problem that a large number of temperature detectors must be provided.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a temperature measuring endoscope capable of performing accurate and stable temperature measurement without causing a temperature change in an infrared fiber or the like.

[0015]

In order to achieve the above object, a temperature measuring endoscope according to the present invention is provided with an infrared transmitting means for transmitting infrared radiation radiated from a portion to be measured in an endoscope insertion portion. In the inserted temperature measuring endoscope, an air supply means for sending gas from the outside into the endoscope insertion section and an exhaust path for discharging gas from the inside of the endoscope insertion section to the outside are provided. It is characterized by.

In addition, one of an inlet gas discharge port for discharging gas into the endoscope insertion portion and an exhaust gas inlet port for taking gas for discharging from the endoscope insertion portion into the exhaust passage is provided. Provided near the end of the endoscope insertion section,
The other may be provided near the base end of the endoscope insertion section.

Further, a constant-temperature gas supply means for feeding a gas of a constant temperature into the endoscope insertion section may be provided in addition to the air supply means, and the temperature of the gas fed into the endoscope insertion section may be plural. Temperature setting means for setting the temperature of the gas to a plurality of different temperatures by setting the temperature of the gas to a plurality of different temperatures. The measurement of infrared rays emitted from the unit may be performed.

[0018]

An embodiment will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes an endoscope insertion portion to be inserted into the inside of a device or a body cavity or the like, and is hermetically sealed by a flexible tube 2.

An infrared image transmitting fiber bundle 3 capable of transmitting an infrared image is inserted into the endoscope insertion section 1. When an indium / antimony detector that detects mid-infrared light at a wavelength of 3 to 5.5 μm is used as an infrared detector of a thermographic device 20 described later, the infrared image transmitting fiber bundle 3 is used to reduce loss in the wavelength range.
For example, a chalcogenide fiber such as arsenic sulfide or a fluoride fiber may be used.

At the distal end 1a of the endoscope insertion section 1, an infrared objective lens 5 is directed forward so that an infrared ray of the measured section 100 is focused on the incident end face 3a of the infrared image transmitting fiber bundle 3. It is arranged. In addition, the endoscope eyepiece 6 formed further outward than the base end of the endoscope insertion portion 1 includes:
An infrared eyepiece 8 is arranged to face the emission end face 3b of the infrared image transmission fiber bundle 3.

The infrared objective lens 5 and the infrared eyepiece 8 are also formed of an infrared transmitting material such as chalcogenide glass, fluoride glass, zinc selenium, germanium or silicon, which transmits the detection wavelength range.

A visible image transmitting fiber bundle for transmitting a visible image is provided in the endoscope insertion section 1 so that the visible image of the measured section 100 can be transferred to the endoscope eyepiece section. Although it can be observed on the 6 side, its illustration is omitted.

A thermography device 20 is connected to the infrared eyepiece 8. An infrared camera 21 includes an infrared detector that detects an infrared image formed by the infrared eyepiece 8 and converts the infrared image into an electric signal. The detection signal output from the infrared camera 21 is a conversion unit. Image processing is performed at 22, and an infrared image of the measured section 100 is displayed on the display 23.

Outside the endoscope, a constant-temperature gas generator 10 for generating a gas of a constant temperature and a constant-temperature gas generated by the constant-temperature gas generator 10 are fed into the endoscope insertion section 1. And an air supply pump 11 are provided. The constant-temperature gas generator 10 may be configured to heat air to a constant temperature by a heater.

The constant-temperature gas sent from the air supply pump 11 is guided into the endoscope insertion section 1 by a highly flexible tube 12 such as a silicon tube. The introduced gas discharge port 12a at the distal end of the tube 12 is disposed inside the distal end portion 1a of the endoscope insertion section 1, from which the constant temperature gas is discharged into the endoscope insertion section 1 and filled.

Reference numeral 13 denotes an exhaust passage for exhausting the gas in the endoscope insertion portion 1 to the atmosphere, and an exhaust intake port 13 for introducing the gas in the endoscope insertion portion 1 to the exhaust passage 13.
a is provided at the base end of the endoscope insertion section 1.

Therefore, the constant temperature gas is supplied to the introduction gas outlet 1
After entering the distal end of the endoscope insertion portion 1 through the endoscope 2a and passing the entire length of the endoscope insertion portion 1, the exhaust intake port 13a
Is released into the atmosphere. The released gas may be returned to the constant temperature gas generator 10 and circulated.

In this way, the inside of the endoscope insertion section 1 is kept at a constant temperature, whereby the temperature of the infrared image transmitting fiber bundle 3 inserted through the inside of the endoscope insertion section 1 is kept constant. It is.

When the temperature measuring endoscope is used, if the environmental temperature at which the endoscope insertion section 1 is inserted is different from room temperature by only a few degrees, instead of using the constant temperature gas generator 10, indoor air is used. May be sent into the endoscope insertion section 1 by the air supply pump 11.

Conversely, when the ambient temperature differs from room temperature by several tens of degrees and the temperature changes drastically, the detection signal from the temperature detector 15 for detecting the temperature in the endoscope insertion section 1 is sent to the gas temperature controller 16. To the gas temperature controller 16
Controls the operation of the constant temperature gas generator 10 and the air supply pump 11 to control the temperature and flow rate of the gas fed into the endoscope insertion section 1.

By doing so, the temperature of the infrared image transmitting fiber bundle 3 in the endoscope insertion section 1 is kept constant and the error of the temperature measurement can be suppressed even in a bad environment for the measurement. Can be.

Further, the gas temperature controller 16 can control the state of the constant temperature gas generator 10 to set the temperature of the gas sent into the endoscope insertion section 1 to an arbitrary temperature. The infrared image transmitting fiber bundle 3 can be maintained at a plurality of different constant temperatures, and in each state, the infrared radiation emitted from the measured section 100 can be measured. By performing such a measurement, the absolute temperature of the measured section 100 can be measured even if the emissivity of the measured section 100 is not known in advance. This will be described below.

The spectral radiance emitted from a black body without surface reflection is calculated by Planck's equation.

M (T _B , λ) = c ₁ [exp (c ₂ / λT _B ) −1] ⁻¹ λ ^-5 (1) where M (T _B , λ) is a unit surface of a black body Energy per unit wavelength of energy released per unit time [Wcm ^-2 ·
μm ^-1 ] λ: wavelength [μm] T _B : temperature of black body [K] c ₁ , c ₂ : first and second radiation constants.

The transmittance of the infrared image transmitting fiber bundle 3;
Assuming that the absorptance and reflectivity are τ, α, and ρ, respectively, τ + α + ρ = 1. Since α = ε holds according to Kirchhoff's law, τ + ε + ρ = 1 (2).

The infrared energy U incident on the infrared camera 21 includes the energy transmitted through the infrared image transmitting fiber bundle 3, the energy radiated from the infrared image transmitting fiber bundle 3 itself, and the infrared image transmitting fiber bundle. It is proportional to the sum of the energy reflected from the three end faces.

U = K {τM (T _B , λ) + ε M (T _F , λ) + ρ M (T _RT , λ)} (3) where K: proportional constant T _F : infrared image transmission fiber bundle 3 temperature T _RT: temperature of measurement environment Therefore, the measurement temperature a temperature of the infrared image transmission fiber bundle 3 is changed also changes.

When measuring the temperature distribution of the measured portion 100, the infrared energy U _RT incident on the infrared camera 21 when the temperature of the infrared image transmitting fiber bundle 3 is the measurement environment temperature is (2) , (3) from the _{U RT = K {τM (T} B, λ) + (1-τ) M (T RT, λ)} ... (4).

The temperature of the infrared image transmitting fiber bundle 3 is set to T
Infrared energy U _F2 incident on the infrared camera 21 in the case of the _F2, likewise _{U F2 = K {τM (T} B, λ) + εM (T F2, λ) + ρM (T RT, λ)} ... (5 ). From equations (2), (4), and (5), U _RT −U _F2 = ε （M (T _RT , λ) −M (T _F2 , λ)｝ (6), and thus ε = ｛M (T _{RT, λ) -M (T F2} , λ) / (U RT -U F2) _{where, M (T RT, λ)} , M (T F2, λ), U RT, U
_{Since F2} is obtained, the emissivity ε can be known.

Therefore, since the emissivity can be determined by measuring the temperature of the infrared image transmitting fiber bundle 3 while changing it, the absolute temperature can be measured even if the emissivity of the measured section 100 is not known in advance, and the unknown temperature can be measured. There is an effect that accurate temperature measurement can be performed even for an object having an emissivity.

The present invention is not limited to the above embodiment. For example, in order to control the temperature inside the endoscope insertion section 1 more stably, some suitable holes are provided in the tube 12. Apart from that, it is also effective to make the gas flow out of the endoscope insertion portion 1 by making the gas come out therefrom, and it is also effective to provide a plurality of tubes having different lengths. . Further, an infrared image may be formed by scanning using an infrared transmission fiber array or the like instead of the infrared image transmission fiber bundle 3.

[0042]

According to the temperature measuring endoscope of the present invention, a gas having a stable temperature is sent from the outside to the inside of the endoscope insertion portion to maintain the temperature of the infrared image transmitting fiber bundle at a constant temperature. Therefore, accurate temperature measurement can be performed without being affected by environmental temperature changes.

Further, by measuring the infrared image transmitting fiber bundle at a plurality of different temperatures and measuring at each of the temperatures, the absolute temperature can be measured even if the emissivity of the measured portion is not known in advance, and the unknown temperature can be measured. Accurate temperature measurement can be performed even for emissivity objects.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment.

FIG. 2 is a diagram showing an experimental result illustrating an occurrence of a temperature measurement error due to a change in environmental temperature.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Endoscope insertion part 3 Infrared image transmission fiber bundle 11 Air supply pump 12 Tube 13 Exhaust path 100 Part to be measured

Claims (4)

(57) [Claims] 1. A temperature measuring endoscope having an infrared image transmitting means for transmitting an image by infrared rays radiated from a portion to be measured inserted through an endoscope insertion portion, wherein the infrared image transmission means is externally inserted into the endoscope insertion portion. An air supply means for feeding gas, an exhaust path for discharging gas from the inside of the endoscope insertion portion to the outside, and a gas sent into the endoscope insertion portion
Temperature setting for setting the gas temperature to several different temperatures
Means for determining the temperature of the gas
The infrared image transmission means is duplicated by setting
Number of different temperatures, and at each temperature the
Can measure infrared radiation emitted from the measuring unit
A temperature measuring endoscope characterized in that: 2. An exhaust gas inlet for discharging gas into the endoscope insertion portion, and an exhaust gas inlet for introducing gas to be discharged from the endoscope insertion portion into the exhaust passage, one of which is: The temperature measuring endoscope according to claim 1, wherein the temperature measuring endoscope is provided near a distal end of the endoscope insertion portion, and the other is provided near a base end of the endoscope insertion portion. 3. The temperature measuring endoscope according to claim 2, wherein intermediate outlets for discharging gas from an intermediate portion of the endoscope insertion portion are provided at a plurality of positions. 4. The temperature-measuring endoscope according to claim 1, wherein a constant-temperature gas supply means for feeding a gas at a constant temperature into the endoscope insertion portion is provided in addition to the air supply means.