KR20180021956A - Optical wave guide using parabolic reflectors and an Infrared gas sensor containing the same - Google Patents

Abstract

The present invention relates to an optical waveguide having a long optical path length by geometrically arranging a reflector and having a high optical efficiency, comprising a first parabolic reflector including a first reflective surface, a second parabolic reflector including a second reflective surface, a third parabolic reflector including a third reflective surface, and at least one planar reflector positioned between the first parabolic reflector and the second parabolic reflector. The first parabolic reflector, the planar reflector, and the second parabolic reflector are disposed so that the first reflective surface, the reflective surface of the planar reflector, and the second reflective surface are opposed to the third reflective surface.

Description

TECHNICAL FIELD [0001] The present invention relates to an optical waveguide using parabolic reflectors and an infrared gas sensor including the parabolic reflector and an infrared gas sensor,

The present invention relates to an optical waveguide using a parabolic reflector and an infrared gas sensor having the optical waveguide.

Nondispersive infrared (NDIR) gas sensors, one of the optical gas sensors, use the property that gas molecules absorb light of a specific wavelength. In order to fabricate a highly sensitive non-dispersive infrared gas sensor, it is necessary to maximize the light absorption of gas molecules. To this end, the length of the optical path, which is the distance that the light emitted from the light source reaches the photodetector, must be lengthened. However, when the optical path length is increased, the amount of light reaching the photodetector decreases in proportion to the square of the distance.

Generally, the optical path consists of an optical waveguide in which the reflector is geometrically designed and arranged so that the light emitted from the light source is reflected by the reflector and reaches the photodetector.

For example, as described above, the nondispersive infrared gas detection utilizes the property that the gas molecules absorb light of a specific wavelength, and the light absorption rate differs from one gas molecule to another. For example, carbon dioxide has a strong light absorptivity (about 99%) at a center wavelength of about 4.26 μm, and carbon monoxide has a weak light absorption rate (about 30%) at a center wavelength of about 4.64 μm. In addition, the CO2 sensor has a relatively high concentration of the measurement area, while the measurement area of the carbon monoxide sensor is a relatively low concentration area. Due to these characteristics, a non-dispersive IR type carbon monoxide sensor requires a light source with strong emittance, a sensitive photodetector, and an optical waveguide having a long optical path length and a high optical efficiency.

According to at least one embodiment of the present invention, there is an object to provide an optical waveguide having a long optical path length and high optical efficiency by geometrically arranging the reflector.

According to at least one embodiment of the present invention, there is an object to provide an infrared gas sensor comprising a reflector geometrically arranged to provide an optical waveguide having a long optical path length and high optical efficiency.

A light pipe according to at least one embodiment of the present invention includes a first parabolic reflector including a first reflector, a second parabolic reflector comprising a second reflector, a third parabolic reflector comprising a third reflector, And at least one planar reflector positioned between the first parabolic reflector and the second parabolic reflector. The first parabolic reflector, the planar reflector, and the second parabolic reflector are arranged so that the first reflective surface, the reflective surface of the planar reflector, and the second reflective surface are opposed to the third reflective surface.

According to at least one embodiment of the present invention, the first parabolic reflector and the second parabolic reflector each have a first optical axis and a second optical axis, wherein the first optical axis and the second optical axis are parallel to each other.

According to at least one embodiment of the present invention, the planar reflector is arranged so that the reflective surface of the planar reflector is located at the focal position of the third parabolic reflector, and the light traveling to the first area is reflected from the first area, To the reflective surface of the planar reflector.

According to at least one embodiment of the present invention, a light detector is disposed at the focus position of the second parabolic reflector, and light traveling to the reflective surface of the planar reflector is reflected by the reflective surface of the planar reflector, Light proceeding to the second area is reflected from the second area and travels along the second optical axis to the second reflection surface, and light traveling to the second reflection surface is transmitted from the second reflection surface And converge to the photodetector.

According to at least one embodiment of the present invention, the first reflective surface, the reflective surface of the planar reflector, and the second reflective surface are located on the same spatially same plane.

According to at least one embodiment of the present invention, the first reflective surface, the reflective surface of the planar reflector, and the second reflective surface are located on different surfaces spatially.

According to at least one embodiment of the invention, the length of the first optical axis and the length of the second optical axis are the same.

According to at least one embodiment of the present invention, the length of the first optical axis and the length of the second optical axis are different.

According to at least one embodiment of the present invention, the first parabolic reflector, the planar reflector, and the second parabolic reflector are formed so that the first reflective surface, the reflective surface of the parabolic reflector, and the second reflective surface are continuous.

According to at least one embodiment of the present invention, the first parabolic reflector, the planar reflector, and the second parabolic reflector have a predetermined spacing between each of the first reflective surface, the reflective surface of the parabolic reflector, and the second reflective surface, .

An infrared gas sensor in accordance with at least one embodiment of the invention includes a light source that emits light, an optical waveguide according to at least one embodiment of the present invention for directing light, and an optical waveguide for detecting light guided through the optical waveguide And a photodetector.

The infrared gas sensor according to at least one embodiment of the present invention further comprises an analyzer for analyzing the output from the photodetector to calculate the concentration of the specific gas in the optical waveguide.

According to at least one embodiment of the present invention, the specific gas comprises carbon monoxide (CO).

According to at least one embodiment of the invention, the light source comprises an incandescent light source and detects the concentration of the specific gas in the light waveguide in a non-dispersive manner using light from the incandescent light source.

According to at least one embodiment of the present invention, the photodetector comprises at least one of a photoelectric element, a superconducting element, and a thermoelectric element.

As described above, according to at least one embodiment of the present invention, the reflector is geometrically arranged to provide an optical waveguide having a long optical path length and high optical efficiency.

The optical system of the optical waveguide according to at least one embodiment of the present invention can solve the chromatic aberration and the spherical aberration problem on the optical path generated in the conventional lens and can realize the miniaturization of the optical system because the optical efficiency is higher than that using the conventional lens. .

The optical system of the optical waveguide according to at least one embodiment of the present invention can configure the optical system of the desired optical path length by appropriately adjusting the position of each parabolic reflector. For example, when the present invention is applied to a gas sensor of a non-dispersion infrared type, a gas sensor having a smaller optical path length can be constructed at the time of gas detection with a high light absorptivity such as carbon dioxide, An effective gas sensor can be constituted by configuring the optical path length to be long at the time of low gas detection.

1 is a graph showing a basic form of a parabolic function.
2 is a conceptual diagram showing an example of condensing using a parabolic reflector.
3 is a top view of an optical waveguide according to at least one embodiment of the present invention.
4 is an enlarged view of a first parabolic reflector (light source side parabolic reflector) and a second parabolic reflector (detection side parabolic reflector) of an optical waveguide according to at least one embodiment of the present invention.
5 is a conceptual diagram of an infrared gas sensor having an optical waveguide according to at least one embodiment of the present invention.

Hereinafter, an optical waveguide using a parabolic reflector according to at least one embodiment of the present invention and a non-dispersion infrared gas sensor having the same will be described in detail with reference to the accompanying drawings.

In a broad sense, a reflector is included in a lens, and unlike a transmissive lens, it can be said to be a reflective lens. However, in the present specification, the scope of a lens of a conventional concept is limited to a transmissive lens, and a reflective lens is called a reflector.

The optical waveguide according to at least one embodiment of the present invention is an optical system having a plurality of parabolic reflectors as a basic constitution. The parabolic reflector has one focal point, and the light emitted from the focal point is reflected from the reflection surface of the parabolic reflector and travels parallel to the optical axis.

1 is a graph showing a basic form of a parabolic function. The light source is located at the origin (O) and the x-axis including the origin is the optical axis.

, 광원에서 방출된 광의 진행하는 방향의 단위 벡터를

, 포물 반사체의 반사면의 법선 단위 벡터를

, 광축인 x축과 평행한 벡터의 단위 벡터를

라 하면 각 벡터는 식(1)~식(4)와 같이 구해진다.The light emitted from the light source is reflected at an arbitrary reflection plane A (x, y) of the parabolic reflector and travels in parallel with the x-axis which is the optical axis. Function of the parabolic reflector

, The unit vector of the traveling direction of the light emitted from the light source

, The normal unit vector of the reflection surface of the parabolic reflector

, A unit vector of a vector parallel to the x axis which is an optical axis

(1) to (4), respectively.

+

식(1)

+

Equation (1)

식(2)

Equation (2)

식(3)

Equation (3)

식(4)

Equation (4)

,

는 각각 x축, y축의 단위벡터이다. 도 1에서 각 벡터의 내적은 식(5) 및 식(6)과 같다.In Equations (1) - (3), ∇ is a differential operator,

,

Are unit vectors of the x-axis and the y-axis, respectively. In Fig. 1, the inner product of each vector is expressed by equations (5) and (6).

식(5)

Equation (5)

식(6)

Equation (6)

Equations (4) and (5) are based on the law of reflection, and the relationship between Eq. (7) and Eq.

식(7)

Equation (7)

Equation (1) - Equation (4) is used to summarize Equation (7) to derive Equation (8).

식(8)

Equation (8)

As shown in Fig. 1, the light reflected from the parabolic reflector in the light emitted from the origin O travels in parallel with the optical axis. Conversely, parallel to the optical axis, the light incident on the parabolic reflector converges to the origin (O). From the optical point of view, the origin (O) can be called the focal point. The closest distance between the focal point and the parabolic reflector is the focal length (f), which is -q / p. Using the focal length (f), Eq. (8) is summarized as Eq. (9).

식(9)

Equation (9)

Equation (9) is a function that serves as a reference for analyzing the parabolic reflector, and the focal length f is an important parameter when designing an optical system using the parabolic reflector. 2 is a conceptual diagram showing an example of condensing using a parabolic reflector.

A reflector is more advantageous than a lens in order to lengthen the optical path length and increase the light condensing property in the optical waveguide. This is because the lens has a limitation in increasing the light efficiency due to spherical aberration and chromatic aberration.

As described above, the optical waveguide according to at least one embodiment of the present invention can be applied to a non-dispersion infrared gas sensor. Non-dispersive infrared gas sensors can be interpreted by the Beer-Lambert Theory.

The light source and the photodetector are basically configured in the simplest form configured to measure the concentration of the gas by using the characteristic that the gas molecule absorbs light of a specific wavelength. The light emitted from the light source reaches the photodetector and uses an optical waveguide to increase the light efficiency reaching the photodetector. In this optical system, as the gas concentration increases, the amount of light absorbed by the gas molecules increases. As a result, the amount of light reaching the photodetector decreases and the electrical signal output from the photodetector decreases. The Beer-Lambertian theory expresses this correlation as Eq. (10).

식(10)

Equation (10)

In the equation (10), I is the quantity of light reaching the photodetector, I ₀ is the quantity of light reaching the photodetector when the gas concentration is 0, the maximum quantity of light, α is the proportionality constant according to the absorption rate of gas molecules, to be.

According to the Beer-Lambertian theory, if the optical path length L is increased for the same gas concentration change, the variation width of I becomes larger. This means that the longer the optical path length, the more precise the gas sensor can be manufactured. If the light absorptance of gas molecules is low relative to the same gas concentration change, the change width of I is small and it is difficult to produce a precise gas sensor. As a result, in order to manufacture a sensor for detecting a gas having a low light absorptance, the optical path length should be maximized.

If the light source is multi-wavelength, it is necessary to solve the spherical aberration and chromatic aberration basically in order to maximize the light efficiency by applying the lens. In particular, chromatic aberration can not be solved with one lens, and consequently, when light is condensed using one lens, a certain amount of light loss due to chromatic aberration may occur.

Despite spherical aberration and chromatic aberration, the focal length of the lens should be shortened and the size of the lens should be increased to increase the light efficiency. However, as the focal length is shortened and the size of the lens is increased, the problem of spherical aberration becomes larger, so that there is a limit to increase the light efficiency in this way. On the other hand, the parabolic reflector does not have the problem of chromatic aberration and spherical aberration, so that the focal distance can be made sufficiently small or the reflective surface of the reflector can be made sufficiently large.

Therefore, according to at least one embodiment of the present invention, an optical waveguide having a high optical efficiency and a long optical path length can be realized by using a parabolic reflector since the solid angle of the parabolic reflector can be made larger than the solid angle of the lens.

FIG. 3 is a plan view of an optical waveguide 300 according to at least one embodiment of the present invention, and FIG. 4 is a perspective view of a first parabolic reflector (light source side parabolic reflector) 305 ) And a second parabolic reflector (parabolic reflector on the detection side) 320. As shown in Fig.

3, the optical waveguide 300 according to at least one embodiment of the present invention includes a first parabolic reflector 310 that includes a first reflective surface 315, a second reflective surface 325 A third parabolic reflector 330 including a third parabolic reflector 320 and a third reflective surface 335 and at least one parabolic reflector 320 positioned between the first parabolic reflector 310 and the second parabolic reflector 320 And a flat reflector 340. In at least one embodiment of the present invention, the first parabolic reflector 310, the planar reflector 340, and the second parabolic reflector 320 comprise a first reflective surface 315, The reflecting surface 345 of the reflector, and the second reflecting surface 325 are disposed so as to face the third reflecting surface 335. [

The first parabolic reflector 310 and the second parabolic reflector 320 each have a first optical axis 311 and a second optical axis 321 and have a first optical axis 311 and a second optical axis 321, The second optical axes 321 are parallel to each other.

A light source 501 (see FIG. 5) is positioned at the focal point of the first parabolic reflector 310 so that the light emitted from the light source is reflected by the first reflection surface 315 and reflected by the third reflection surface 325 in the first area 325a.

In at least one embodiment of the present invention, the planar reflector 340 is positioned such that the reflective surface 345 of the planar reflector 340 is located at the focal point of the third parabolic reflector 330, and the first area 335a, Is reflected from the first area 335a and advances to the reflecting surface 345 of the planar reflector 340 at a predetermined angle.

In at least one embodiment of the present invention, a light detector 505 (see FIG. 5) is disposed at the focus position of the second parabolic reflector 320 and light traveling to the reflective surface 345 of the planar reflector 340 The light reflected by the reflective surface 345 of the planar reflector 340 travels to the second area 335b of the third reflective surface 335 at a predetermined angle and light traveling to the second area 335b is reflected by the second area 335b, The light reflected from the second reflection surface 325 is reflected by the second reflection surface 335b and travels along the second optical axis 321 to the second reflection surface 325. The light that has propagated to the second reflection surface 325 is reflected from the second reflection surface 325, 505, see Fig. 5).

5) is the dispersed light, the size of the first parabolic reflector 310 is set such that the size of the first parabolic reflector 310 is smaller than that of the first reflective surface 315 in order to minimize the loss of light emitted from the light source 501 It should be not less than spot size of light.

In at least one embodiment of the invention, the first reflective surface 315, the reflective surface 345 of the planar reflector 340, and the second reflective surface 325 are located on the same spatially same plane.

In at least one embodiment of the invention, the first reflective surface 315, the reflective surface 345 of the planar reflector 340, and the second reflective surface 325 are spatially on different planes.

In at least one embodiment of the invention, the length of the first optical axis 311 and the length of the second optical axis 321 are the same. By structuring the length of the first optical axis 311 and the length of the second optical axis 321 the same, it is possible to simplify the structure so that the optical waveguide can be easily manufactured.

In at least one embodiment of the invention, the length of the first optical axis 311 and the length of the second optical axis 321 are different. By configuring the length of the first optical axis 311 and the length of the second optical axis 321 to be different from each other, various structures can be used at the time of manufacturing the optical waveguide, thereby increasing the degree of freedom in manufacturing.

In at least one embodiment of the present invention, the first parabolic reflector 310, the planar reflector 340 and the second parabolic reflector 320 comprise a first reflective surface 315, a reflective surface 340 of the parabolic reflector 340 345, and the second reflecting surface 325 are formed to be continuous.

In at least one embodiment of the present invention, the first parabolic reflector 310, the planar reflector 340 and the second parabolic reflector 320 comprise a first reflective surface 315, a reflective surface 340 of the parabolic reflector 340 345, and the second reflecting surface 325 with a predetermined gap therebetween.

In order to increase the light path length and increase the light efficiency by using the optical waveguide, each parabolic reflector has a metal coating inside. The luster of metal is caused by the free electrons of the metal, and reflection occurs by the interaction of free electrons and electromagnetic waves. At this time, the reflectance of the metal coated reflective surface is determined by the conductivity of the metal. That is, a metal having a high conductivity generally has excellent light reflectance.

The metals used for the metal coating are aluminum (Al), silver (Ag), gold (Au), copper (Cu), etc. The reflectance of these metals is about 98.2%, 99.4%, 99.2% , 98.7%.

Reflectivity in Metal Coatings for Infrared Near 4 μm The next thing to consider is the robustness of the metal coating. That is, when a change in the coated surface occurs, the reflectance changes and the amount of light changes. Therefore, when the light amount is measured and converted into the density, an error occurs in the measured value. Considering the corrosion and the change in reflectivity with time, the optimum metal is gold, and in at least one embodiment of the present invention, gold is used for the metal coating.

The coating method is generally a vapor deposition or plating used for metal coating. The deposition is a method of depositing metal atoms in a gaseous state on a substrate by evaporating the metal to a high temperature, and the plating is a method of melting a compound containing metal and attaching it to the substrate through electrolysis.

When the electromagnetic wave is reflected from the surface of the metal, it penetrates to a certain depth from the surface of the metal. The depth until the intensity of the electromagnetic wave decreases to 1 / e is called the surface depth. That is, the electromagnetic wave is not reflected on the surface of the metal but is reflected in a form that penetrates to a certain depth of the metal. If the thickness of the metal is thin, a part of the electromagnetic wave is transmitted and the reflection loss as much as the transmitted is generated.

In an embodiment of the present invention, gold is coated on the parabolic reflector with a thickness of 0.3 占 퐉 or more by using a metal coating in consideration of the surface depth of gold (about 0.11 占 퐉).

Thus, in accordance with at least one embodiment of the present invention, there is provided a reflective optical system comprising a first parabolic reflector comprising a first reflector, a second parabolic reflector comprising a second reflector, a third parabolic reflector comprising a third reflector, And at least one planar reflector positioned between the first parabolic reflector and the second parabolic reflector, wherein the first parabolic reflector, the planar reflector, and the second parabolic reflector comprise a first reflector, a reflective surface of the planar reflector, And the second reflection surface is disposed so as to face the third reflection surface.

Therefore, according to at least one embodiment of the present invention, the reflector can be geometrically arranged to provide an optical waveguide having a long optical path length and high optical efficiency.

In addition, according to at least one embodiment of the present invention, chromatic aberration generated in a conventional lens and spherical aberration on an optical path can be solved, and optical efficiency is higher than that using a conventional lens, so that miniaturization of an optical system can be realized .

Further, according to at least one embodiment of the present invention, an optical system having a desired optical path length can be constructed by appropriately adjusting the position of each parabolic reflector. For example, when the present invention is applied to a gas sensor of a non-dispersion infrared type, a gas sensor having a smaller optical path length can be constructed at the time of gas detection with a high light absorptivity such as carbon dioxide, An effective gas sensor can be constituted by configuring the optical path length to be long at the time of low gas detection.

5 is a conceptual diagram of an infrared gas sensor 500 having an optical waveguide 300 according to at least one embodiment of the present invention.

5, an infrared gas sensor 500 according to at least one embodiment of the present invention includes a light source 501 for emitting light, an optical waveguide 300 for guiding light, And a photodetector 505 for detecting the light guided through the photodetector.

The infrared gas sensor 500 according to at least one embodiment of the present invention further comprises an analyzer 510 for analyzing the output from the photodetector 505 to calculate the concentration of a specific gas in the optical waveguide 300 .

In at least one embodiment of the present invention, the light source 501 includes an incandescent light source and uses the light from the incandescent light source to detect the concentration of a specific gas in the light pipe 300 in a non-dispersive manner.

In at least one embodiment of the present invention, the specific gas comprises carbon monoxide (CO).

In at least one embodiment of the present invention, the photodetector 505 includes at least one of a photoelectric element, a pyroelectric element, and a thermoelectric element.

Carbon monoxide (CO) is a gas that is often generated in incomplete combustion of fossil fuels. Its molecules are binary molecules composed of one carbon atom and one oxygen atom.

The non-dispersive infrared gas sensor is a gas sensor that measures the light absorption rate with respect to the gas concentration by using the characteristic that the gas molecule absorbs the light of a specific wavelength (infrared ray) to obtain the concentration.

Since the gas molecules react optically with respect to a specific wavelength, the light source used therein must be short wavelength. For this purpose, a single wavelength is selected through the use of a spectroscope such as a prism in a light having a plurality of wavelengths, or a light source of a short wavelength is used. Particularly, a method using a spectroscopic element is called a dispersion method. On the other hand, a gas molecule absorbs only light of a specific wavelength, so that light of various wavelengths is irradiated to gas molecules, and a method of filtering only light of a wavelength band absorbed by gas molecules by an optical filter is called a non-dispersion method.

In case of using a laser or an LED as a light source of short wavelength or a light source of short wavelength by using a dispersing device in a white light, it is necessary to separately develop a light source having a high or low wavelength and a dispersing device. On the other hand, the non-dispersion infrared method has merits such that the system is simple and the cost is low because only the optical filter which transmits only the corresponding wavelength is attached to the photodetector.

Therefore, according to at least one embodiment of the present invention, an efficient gas sensor can be constituted by arranging the reflectors geometrically and using an optical waveguide having a long optical path length and a high optical efficiency to construct a long optical path length.

The foregoing description is merely illustrative of the technical idea of the present embodiment, and various modifications and changes may be made to those skilled in the art without departing from the essential characteristics of the embodiments. Therefore, the present embodiments are to be construed as illustrative rather than restrictive, and the scope of the technical idea of the present embodiment is not limited by these embodiments. The scope of protection of the present embodiment should be construed according to the following claims, and all technical ideas within the scope of equivalents thereof should be construed as being included in the scope of the present invention.

300: optical waveguide 301: light source
310: first parabolic reflector 311: first parabolic reflector
315: first reflection surface 320: second parabolic reflector
321: second optical axis 325: second reflection surface
330: Third parabolic reflector 335: Third reflective surface
335a: first region 335b: second region
340: plane reflector 345:
370: Photodetector 500: Infrared gas sensor
510: Analyzer

Claims (15)

A first parabolic reflector comprising a first reflector;
A second parabolic reflector including a second reflective surface;
A third parabolic reflector including a third reflector; And
At least one planar reflector positioned between the first parabolic reflector and the second parabolic reflector
And,
Wherein the first parabolic reflector, the second parabolic reflector, and the second parabolic reflector are arranged so that the first reflective surface, the reflective surface of the planar reflector, and the second reflective surface are opposed to the third reflective surface,
Optical waveguide.
The method according to claim 1,
The first parabolic reflector and the second parabolic reflector each having a first optical axis and a second optical axis,
Wherein the first optical axis and the second optical axis are parallel to each other,
Wherein a light source is located at the focus of the first parabolic reflector so that light emitted from the light source is reflected by the first reflection surface and proceeds to the first area of the third reflection surface along the first optical axis.
Optical waveguide.
3. The method of claim 2,
Wherein the planar reflector is disposed such that the reflective surface of the planar reflector is located at a focal position of the third parabolic reflector,
The light traveling to the first area is reflected from the first area and advances to the reflecting surface of the plane reflector at an angle.
Optical waveguide.
The method of claim 3,
A photodetector is disposed at a focus position of the second parabolic reflector,
The light traveling to the reflection surface of the plane reflector is reflected by the reflection surface of the plane reflector and proceeds to the second region of the third reflection surface at the predetermined angle,
Wherein light traveling to the second region is reflected from the second region and travels to a second reflection surface along a second optical axis,
And the light reflected by the second reflecting surface is converged to the photodetector,
Optical waveguide.
5. The method according to any one of claims 1 to 4,
Wherein the first reflective surface, the reflective surface of the planar reflector, and the second reflective surface are located on a spatially identical plane,
Optical waveguide.
5. The method according to any one of claims 1 to 4,
Wherein the first reflective surface, the reflective surface of the planar reflector, and the second reflective surface are located on spatially different surfaces,
Optical waveguide.
5. The method according to any one of claims 1 to 4,
The length of the first optical axis is equal to the length of the second optical axis,
Optical waveguide.
5. The method according to any one of claims 1 to 4,
Wherein a length of the first optical axis and a length of the second optical axis are different from each other,
Optical waveguide.
5. The method according to any one of claims 1 to 4,
Wherein the first parabolic reflector, the second parabolic reflector, and the second parabolic reflector are formed so that the first reflective surface, the reflective surface of the planar reflector, and the second reflective surface are continuous,
Optical waveguide.
5. The method according to any one of claims 1 to 4,
Wherein the first parabolic reflector, the second parabolic reflector, the second parabolic reflector, and the second parabolic reflector are formed at predetermined intervals between the first reflective surface, the reflective surface of the parabolic reflector,
Optical waveguide.
A light source for emitting light;
An optical waveguide according to any one of claims 1 to 10 for guiding the light; And
And a photodetector for detecting the light guided through the optical waveguide.
Infrared gas sensor.
12. The method of claim 11,
Further comprising an analyzing device for analyzing an output from the photodetector to calculate a concentration of a specific gas in the optical waveguide,
Infrared gas sensor.
13. The method of claim 12,
Wherein the specific gas comprises carbon monoxide (CO)
Infrared gas sensor.
12. The method of claim 11,
Wherein the light source comprises an incandescent light source,
Detecting a concentration of a specific gas in the optical waveguide in a non-dispersion manner using light from the incandescent light source,
Infrared gas sensor.
12. The method of claim 11,
Wherein the photodetector comprises at least one of a photoelectric element, a pyroelectric element, and a thermoelectric element,
Infrared gas sensor.

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